The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.
An aquatic genus of the family, Pipidae, occurring in Africa and distinguished by having black horny claws on three inner hind toes.
Proteins obtained from various species of Xenopus. Included here are proteins from the African clawed frog (XENOPUS LAEVIS). Many of these proteins have been the subject of scientific investigations in the area of MORPHOGENESIS and development.
Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).
The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.
Profound physical changes during maturation of living organisms from the immature forms to the adult forms, such as from TADPOLES to frogs; caterpillars to BUTTERFLIES.
A mature haploid female germ cell extruded from the OVARY at OVULATION.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
The developmental stage that follows BLASTULA or BLASTOCYST. It is characterized by the morphogenetic cell movements including invagination, ingression, and involution. Gastrulation begins with the formation of the PRIMITIVE STREAK, and ends with the formation of three GERM LAYERS, the body plan of the mature organism.
The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
Phospholipoglycoproteins produced in the fat body of egg-laying animals such as non-mammalian VERTEBRATES; ARTHROPODS; and others. Vitellogenins are secreted into the HEMOLYMPH, and taken into the OOCYTES by receptor-mediated ENDOCYTOSIS to form the major yolk proteins, VITELLINS. Vitellogenin production is under the regulation of steroid hormones, such as ESTRADIOL and JUVENILE HORMONES in insects.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
An early non-mammalian embryo that follows the MORULA stage. A blastula resembles a hollow ball with the layer of cells surrounding a fluid-filled cavity (blastocele). The layer of cells is called BLASTODERM.
Synthetic transcripts of a specific DNA molecule or fragment, made by an in vitro transcription system. This cRNA can be labeled with radioactive uracil and then used as a probe. (King & Stansfield, A Dictionary of Genetics, 4th ed)
A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
The complex processes of initiating CELL DIFFERENTIATION in the embryo. The precise regulation by cell interactions leads to diversity of cell types and specific pattern of organization (EMBRYOGENESIS).
The middle germ layer of an embryo derived from three paired mesenchymal aggregates along the neural tube.
The outer of the three germ layers of an embryo.
The process of germ cell development in the female from the primordial germ cells through OOGONIA to the mature haploid ova (OVUM).
Preparations of cell constituents or subcellular materials, isolates, or substances.
Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
Chromatophores (large pigment cells of fish, amphibia, reptiles and many invertebrates) which contain melanin. Short term color changes are brought about by an active redistribution of the melanophores pigment containing organelles (MELANOSOMES). Mammals do not have melanophores; however they have retained smaller pigment cells known as MELANOCYTES.
Constituent of the 50S subunit of prokaryotic ribosomes containing about 120 nucleotides and 34 proteins. It is also a constituent of the 60S subunit of eukaryotic ribosomes. 5S rRNA is involved in initiation of polypeptide synthesis.
One of several general transcription factors that are specific for RNA POLYMERASE III. It is a zinc finger (ZINC FINGERS) protein and is required for transcription of 5S ribosomal genes.
The processes occurring in early development that direct morphogenesis. They specify the body plan ensuring that cells will proceed to differentiate, grow, and diversify in size and shape at the correct relative positions. Included are axial patterning, segmentation, compartment specification, limb position, organ boundary patterning, blood vessel patterning, etc.
The entire nerve apparatus, composed of a central part, the brain and spinal cord, and a peripheral part, the cranial and spinal nerves, autonomic ganglia, and plexuses. (Stedman, 26th ed)
Transport proteins that carry specific substances in the blood or across cell membranes.
The development of anatomical structures to create the form of a single- or multi-cell organism. Morphogenesis provides form changes of a part, parts, or the whole organism.
A family of histone molecular chaperones that play roles in sperm CHROMATIN decondensation and CHROMATIN ASSEMBLY in fertilized eggs. They were originally discovered in XENOPUS egg extracts as histone-binding factors that mediate nucleosome formation in vitro.
A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.
The rate dynamics in chemical or physical systems.
ANIMALS whose GENOME has been altered by GENETIC ENGINEERING, or their offspring.
The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. (Dorland, 28th ed)
The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.
The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
In anatomical terms, "tail" is not used as a medical definition to describe any part of the human body; it is however used in veterinary medicine to refer to the distal portion of the spine in animals possessing tails.
A cartilaginous rod of mesodermal cells at the dorsal midline of all CHORDATE embryos. In lower vertebrates, notochord is the backbone of support. In the higher vertebrates, notochord is a transient structure, and segments of the vertebral column will develop around it. Notochord is also a source of midline signals that pattern surrounding tissues including the NEURAL TUBE development.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.
Proteins prepared by recombinant DNA technology.
Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Activins are produced in the pituitary, gonads, and other tissues. By acting locally, they stimulate pituitary FSH secretion and have diverse effects on cell differentiation and embryonic development. Activins are glycoproteins that are hetero- or homodimers of INHIBIN-BETA SUBUNITS.
Membrane transporters that co-transport two or more dissimilar molecules in the same direction across a membrane. Usually the transport of one ion or molecule is against its electrochemical gradient and is "powered" by the movement of another ion or molecule with its electrochemical gradient.
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
VERTEBRATES belonging to the class amphibia such as frogs, toads, newts and salamanders that live in a semiaquatic environment.
The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.
Elements of limited time intervals, contributing to particular results or situations.
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
Protein kinase that drives both the mitotic and meiotic cycles in all eukaryotic organisms. In meiosis it induces immature oocytes to undergo meiotic maturation. In mitosis it has a role in the G2/M phase transition. Once activated by CYCLINS; MPF directly phosphorylates some of the proteins involved in nuclear envelope breakdown, chromosome condensation, spindle assembly, and the degradation of cyclins. The catalytic subunit of MPF is PROTEIN P34CDC2.
A group of adenine ribonucleotides in which the phosphate residues of each adenine ribonucleotide act as bridges in forming diester linkages between the ribose moieties.
The fertilized OVUM resulting from the fusion of a male and a female gamete.
Undifferentiated cells resulting from cleavage of a fertilized egg (ZYGOTE). Inside the intact ZONA PELLUCIDA, each cleavage yields two blastomeres of about half size of the parent cell. Up to the 8-cell stage, all of the blastomeres are totipotent. The 16-cell MORULA contains outer cells and inner cells.
Proteins encoded by homeobox genes (GENES, HOMEOBOX) that exhibit structural similarity to certain prokaryotic and eukaryotic DNA-binding proteins. Homeodomain proteins are involved in the control of gene expression during morphogenesis and development (GENE EXPRESSION REGULATION, DEVELOPMENTAL).
Proteins which are found in eggs (OVA) from any species.
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
The fusion of a spermatozoon (SPERMATOZOA) with an OVUM thus resulting in the formation of a ZYGOTE.
Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)
A process of complicated morphogenetic cell movements that reorganizes a bilayer embryo into one with three GERM LAYERS and specific orientation (dorsal/ventral; anterior/posterior). Gastrulation describes the germ layer development of a non-mammalian BLASTULA or that of a mammalian BLASTOCYST.
Morphological and physiological development of EMBRYOS.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
The plasma membrane of the egg.
Detection of RNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
A large collection of DNA fragments cloned (CLONING, MOLECULAR) from a given organism, tissue, organ, or cell type. It may contain complete genomic sequences (GENOMIC LIBRARY) or complementary DNA sequences, the latter being formed from messenger RNA and lacking intron sequences.
Proteins containing a region of conserved sequence, about 200 amino acids long, which encodes a particular sequence specific DNA binding domain (the T-box domain). These proteins are transcription factors that control developmental pathways. The prototype of this family is the mouse Brachyury (or T) gene product.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.
An order of the class Amphibia, which includes several families of frogs and toads. They are characterized by well developed hind limbs adapted for jumping, fused head and trunk and webbed toes. The term "toad" is ambiguous and is properly applied only to the family Bufonidae.
Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.
Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.
The two longitudinal ridges along the PRIMITIVE STREAK appearing near the end of GASTRULATION during development of nervous system (NEURULATION). The ridges are formed by folding of NEURAL PLATE. Between the ridges is a neural groove which deepens as the fold become elevated. When the folds meet at midline, the groove becomes a closed tube, the NEURAL TUBE.
A type of CELL NUCLEUS division, occurring during maturation of the GERM CELLS. Two successive cell nucleus divisions following a single chromosome duplication (S PHASE) result in daughter cells with half the number of CHROMOSOMES as the parent cells.
Short fragments of DNA or RNA that are used to alter the function of target RNAs or DNAs to which they hybridize.
Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.
The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.
Bone-growth regulatory factors that are members of the transforming growth factor-beta superfamily of proteins. They are synthesized as large precursor molecules which are cleaved by proteolytic enzymes. The active form can consist of a dimer of two identical proteins or a heterodimer of two related bone morphogenetic proteins.
Natural hormones secreted by the THYROID GLAND, such as THYROXINE, and their synthetic analogs.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
The inner of the three germ layers of an embryo.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)
The relationship between the dose of an administered drug and the response of the organism to the drug.
A type of CELL NUCLEUS division by means of which the two daughter nuclei normally receive identical complements of the number of CHROMOSOMES of the somatic cells of the species.
General term for a number of inherited defects of amino acid metabolism in which there is a deficiency or absence of pigment in the eyes, skin, or hair.
A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
The family of true toads belonging to the order Anura. The genera include Bufo, Ansonia, Nectophrynoides, and Atelopus.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.
Short chains of RNA (100-300 nucleotides long) that are abundant in the nucleus and usually complexed with proteins in snRNPs (RIBONUCLEOPROTEINS, SMALL NUCLEAR). Many function in the processing of messenger RNA precursors. Others, the snoRNAs (RNA, SMALL NUCLEOLAR), are involved with the processing of ribosomal RNA precursors.
Wnt proteins are a large family of secreted glycoproteins that play essential roles in EMBRYONIC AND FETAL DEVELOPMENT, and tissue maintenance. They bind to FRIZZLED RECEPTORS and act as PARACRINE PROTEIN FACTORS to initiate a variety of SIGNAL TRANSDUCTION PATHWAYS. The canonical Wnt signaling pathway stabilizes the transcriptional coactivator BETA CATENIN.
The sum of the weight of all the atoms in a molecule.
The striated muscle groups which move the LARYNX as a whole or its parts, such as altering tension of the VOCAL CORDS, or size of the slit (RIMA GLOTTIDIS).
The material of CHROMOSOMES. It is a complex of DNA; HISTONES; and nonhistone proteins (CHROMOSOMAL PROTEINS, NON-HISTONE) found within the nucleus of a cell.
Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.
Cellular proteins encoded by the c-mos genes (GENES, MOS). They function in the cell cycle to maintain MATURATION PROMOTING FACTOR in the active state and have protein-serine/threonine kinase activity. Oncogenic transformation can take place when c-mos proteins are expressed at the wrong time.
A secreted matrix metalloproteinase that is believed to play a role in EXTRACELLULAR MATRIX remodeling and cell fate determination during normal and pathological processes. Matrix metalloproteinase 11 was originally isolated in primary BREAST NEOPLASMS and may be involved in the process of tumorigenesis.
The organ of sight constituting a pair of globular organs made up of a three-layered roughly spherical structure specialized for receiving and responding to light.
A post-MORULA preimplantation mammalian embryo that develops from a 32-cell stage into a fluid-filled hollow ball of over a hundred cells. A blastocyst has two distinctive tissues. The outer layer of trophoblasts gives rise to extra-embryonic tissues. The inner cell mass gives rise to the embryonic disc and eventual embryo proper.
The region in the dorsal ECTODERM of a chordate embryo that gives rise to the future CENTRAL NERVOUS SYSTEM. Tissue in the neural plate is called the neuroectoderm, often used as a synonym of neural plate.
Proteins that are preferentially expressed or upregulated during FETAL DEVELOPMENT.
Contractile tissue that produces movement in animals.
Ion channels that specifically allow the passage of SODIUM ions. A variety of specific sodium channel subtypes are involved in serving specialized functions such as neuronal signaling, CARDIAC MUSCLE contraction, and KIDNEY function.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
The process by which a DNA molecule is duplicated.
The relationships of groups of organisms as reflected by their genetic makeup.
Characteristic restricted to a particular organ of the body, such as a cell type, metabolic response or expression of a particular protein or antigen.
Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.
Complexes of RNA-binding proteins with ribonucleic acids (RNA).
DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.
Paired, segmented masses of MESENCHYME located on either side of the developing spinal cord (neural tube). Somites derive from PARAXIAL MESODERM and continue to increase in number during ORGANOGENESIS. Somites give rise to SKELETON (sclerotome); MUSCLES (myotome); and DERMIS (dermatome).
Biologically active DNA which has been formed by the in vitro joining of segments of DNA from different sources. It includes the recombination joint or edge of a heteroduplex region where two recombining DNA molecules are connected.
A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.
Goosecoid protein is a homeodomain protein that was first identified in XENOPUS. It is found in the SPEMANN ORGANIZER of VERTEBRATES and plays an important role in neuronal CELL DIFFERENTIATION and ORGANOGENESIS.
Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.
The physiological renewal, repair, or replacement of tissue.

Bcl-2 regulates amplification of caspase activation by cytochrome c. (1/11334)

Caspases, a family of specific proteases, have central roles in apoptosis [1]. Caspase activation in response to diverse apoptotic stimuli involves the relocalisation of cytochrome c from mitochondria to the cytoplasm where it stimulates the proteolytic processing of caspase precursors. Cytochrome c release is controlled by members of the Bcl-2 family of apoptosis regulators [2] [3]. The anti-apoptotic members Bcl-2 and Bcl-xL may also control caspase activation independently of cytochrome c relocalisation or may inhibit a positive feedback mechanism [4] [5] [6] [7]. Here, we investigate the role of Bcl-2 family proteins in the regulation of caspase activation using a model cell-free system. We found that Bcl-2 and Bcl-xL set a threshold in the amount of cytochrome c required to activate caspases, even in soluble extracts lacking mitochondria. Addition of dATP (which stimulates the procaspase-processing factor Apaf-1 [8] [9]) overcame inhibition of caspase activation by Bcl-2, but did not prevent the control of cytochrome c release from mitochondria by Bcl-2. Cytochrome c release was accelerated by active caspase-3 and this positive feedback was negatively regulated by Bcl-2. These results provide evidence for a mechanism to amplify caspase activation that is suppressed at several distinct steps by Bcl-2, even after cytochrome c is released from mitochondria.  (+info)

Angiotensin II type 1 receptor-mediated inhibition of K+ channel subunit kv2.2 in brain stem and hypothalamic neurons. (2/11334)

Angiotensin II (Ang II) has powerful modulatory actions on cardiovascular function that are mediated by specific receptors located on neurons within the hypothalamus and brain stem. Incubation of neuronal cocultures of rat hypothalamus and brain stem with Ang II elicits an Ang II type 1 (AT1) receptor-mediated inhibition of total outward K+ current that contributes to an increase in neuronal firing rate. However, the exact K+ conductance(s) that is inhibited by Ang II are not established. Pharmacological manipulation of total neuronal outward K+ current revealed a component of K+ current sensitive to quinine, tetraethylammonium, and 4-aminopyridine, with IC50 values of 21.7 micromol/L, 1.49 mmol/L, and 890 micromol/L, respectively, and insensitive to alpha-dendrotoxin (100 to 500 nmol/L), charybdotoxin (100 to 500 nmol/L), and mast cell degranulating peptide (1 micromol/L). Collectively, these data suggest the presence of Kv2.2 and Kv3.1b. Biophysical examination of the quinine-sensitive neuronal K+ current demonstrated a macroscopic conductance with similar biophysical properties to those of Kv2.2 and Kv3.1b. Ang II (100 nmol/L), in the presence of the AT2 receptor blocker PD123,319, elicited an inhibition of neuronal K+ current that was abolished by quinine (50 micromol/L). Reverse transcriptase-polymerase chain reaction analysis confirmed the presence of Kv2.2 and Kv3.1b mRNA in these neurons. However, Western blot analyses demonstrated that only Kv2.2 protein was present. Coexpression of Kv2.2 and the AT1 receptor in Xenopus oocytes demonstrated an Ang II-induced inhibition of Kv2.2 current. Therefore, these data suggest that inhibition of Kv2.2 contributes to the AT1 receptor-mediated reduction of neuronal K+ current and subsequently to the modulation of cardiovascular function.  (+info)

Molecular dynamics of the sodium channel pore vary with gating: interactions between P-segment motions and inactivation. (3/11334)

Disulfide trapping studies have revealed that the pore-lining (P) segments of voltage-dependent sodium channels undergo sizable motions on a subsecond time scale. Such motions of the pore may be necessary for selective ion translocation. Although traditionally viewed as separable properties, gating and permeation are now known to interact extensively in various classes of channels. We have investigated the interaction of pore motions and voltage-dependent gating in micro1 sodium channels engineered to contain two cysteines within the P segments. Rates of catalyzed internal disulfide formation (kSS) were measured in K1237C+W1531C mutant channels expressed in oocytes. During repetitive voltage-clamp depolarizations, increasing the pulse duration had biphasic effects on the kSS, which first increased to a maximum at 200 msec and then decreased with longer depolarizations. This result suggested that occupancy of an intermediate inactivation state (IM) facilitates pore motions. Consistent with the known antagonism between alkali metals and a component of slow inactivation, kSS varied inversely with external [Na+]o. We examined the converse relationship, namely the effect of pore flexibility on gating, by measuring recovery from inactivation in Y401C+E758C (YC/EC) channels. Under oxidative conditions, recovery from inactivation was slower than in a reduced environment in which the spontaneous YC/EC cross-link is disrupted. The most prominent effects were slowing of a component with intermediate recovery kinetics, with diminution of its relative amplitude. We conclude that occupancy of an intermediate inactivation state facilitates motions of the P segments; conversely, flexibility of the P segments alters an intermediate component of inactivation.  (+info)

Histone octamer transfer by a chromatin-remodeling complex. (4/11334)

RSC, an abundant, essential chromatin-remodeling complex related to SWI/SNF complex, catalyzes the transfer of a histone octamer from a nucleosome core particle to naked DNA. The newly formed octamer-DNA complex is identical with a nucleosome in all respects. The reaction requires ATP and involves an activated RSC-nucleosome intermediate. The mechanism may entail formation of a duplex displacement loop on the nucleosome, facilitating the entry of exogeneous DNA and the release of the endogenous molecule.  (+info)

KCNQ4, a novel potassium channel expressed in sensory outer hair cells, is mutated in dominant deafness. (5/11334)

Potassium channels regulate electrical signaling and the ionic composition of biological fluids. Mutations in the three known genes of the KCNQ branch of the K+ channel gene family underlie inherited cardiac arrhythmias (in some cases associated with deafness) and neonatal epilepsy. We have now cloned KCNQ4, a novel member of this branch. It maps to the DFNA2 locus for a form of nonsyndromic dominant deafness. In the cochlea, it is expressed in sensory outer hair cells. A mutation in this gene in a DFNA2 pedigree changes a residue in the KCNQ4 pore region. It abolishes the potassium currents of wild-type KCNQ4 on which it exerts a strong dominant-negative effect. Whereas mutations in KCNQ1 cause deafness by affecting endolymph secretion, the mechanism leading to KCNQ4-related hearing loss is intrinsic to outer hair cells.  (+info)

Phosphorylation of yeast TBP by protein kinase CK2 reduces its specific binding to DNA. (6/11334)

Protein kinase CK2 is a ubiquitous Ser/Thr kinase which phosphorylates a large number of proteins including several transcription factors. Recombinant Xenopus laevis CK2 phosphorylates both recombinant Saccharomyces cerevisiae and Schizosaccharomyces pombe TATA binding protein (TBP). The phosphorylation of TBP by CK2 reduces its binding activity to the TATA box. CK2 copurifies with the transcription factor IID (TFIID) complex from HeLa cell extracts and phosphorylates several of the TBP-associated factors within TFIID. Taken together these findings argue for a role of CK2 in the control of transcription by RNA polymerase II through the modulation of the binding activity of TBP to the TATA box.  (+info)

In vivo formation of Cu,Zn superoxide dismutase disulfide bond in Escherichia coli. (7/11334)

We have found that the in vivo folding of periplasmic Escherichia coli Cu,Zn superoxide dismutase is assisted by DsbA, which catalyzes the efficient formation of its single disulfide bond, whose integrity is essential to ensure full catalytic activity to the enzyme. In line with these findings, we also report that the production of recombinant Xenopus laevis Cu,Zn superoxide dismutase is enhanced when the enzyme is exported in the periplasmic space or is expressed in thioredoxin reductase mutant strains. Our data show that inefficient disulfide bond oxidation in the bacterial cytoplasm inhibits Cu,Zn superoxide dismutase folding in this cellular compartment.  (+info)

Cu(II) inhibition of the proton translocation machinery of the influenza A virus M2 protein. (8/11334)

The homotetrameric M2 integral membrane protein of influenza virus forms a proton-selective ion channel. An essential histidine residue (His-37) in the M2 transmembrane domain is believed to play an important role in the conduction mechanism of this channel. Also, this residue is believed to form hydrogen-bonded interactions with the ammonium group of the anti-viral compound, amantadine. A molecular model of this channel suggests that the imidazole side chains of His-37 from symmetry-related monomers of the homotetrameric pore converge to form a coordination site for transition metals. Thus, membrane currents of oocytes of Xenopus laevis expressing the M2 protein were recorded when the solution bathing the oocytes contained various transition metals. Membrane currents were strongly and reversibly inhibited by Cu2+ with biphasic reaction kinetics. The biphasic inhibition curves may be explained by a two-site model involving a fast-binding peripheral site with low specificity for divalent metal ions, as well as a high affinity site (Kdiss approximately 2 microM) that lies deep within the pore and shows rather slow-binding kinetics (kon = 18.6 +/- 0.9 M-1 s-1). The pH dependence of the interaction with the high affinity Cu2+-binding site parallels the pH dependence of inhibition by amantadine, which has previously been ascribed to protonation of His-37. The voltage dependence of the inhibition at the high affinity site indicates that the binding site lies within the transmembrane region of the pore. Furthermore, the inhibition by Cu2+ could be prevented by prior application of the reversible blocker of M2 channel activity, BL-1743, providing further support for the location of the site within the pore region of M2. Finally, substitutions of His-37 by alanine or glycine eliminated the high affinity site and resulted in membrane currents that were only partially inhibited at millimolar concentrations of Cu2+. Binding of Cu2+ to the high affinity site resulted in an approximately equal inhibition of both inward and outward currents. The wild-type protein showed very high specificity for Cu2+ and was only partially inhibited by 1 mM Ni2+, Pt2+, and Zn2+. These data are discussed in terms of the functional role of His-37 in the mechanism of proton translocation through the channel.  (+info)

"Xenopus laevis" is not a medical term itself, but it refers to a specific species of African clawed frog that is often used in scientific research, including biomedical and developmental studies. Therefore, its relevance to medicine comes from its role as a model organism in laboratories.

In a broader sense, Xenopus laevis has contributed significantly to various medical discoveries, such as the understanding of embryonic development, cell cycle regulation, and genetic research. For instance, the Nobel Prize in Physiology or Medicine was awarded in 1963 to John R. B. Gurdon and Sir Michael J. Bishop for their discoveries concerning the genetic mechanisms of organism development using Xenopus laevis as a model system.

"Xenopus" is not a medical term, but it is a genus of highly invasive aquatic frogs native to sub-Saharan Africa. They are often used in scientific research, particularly in developmental biology and genetics. The most commonly studied species is Xenopus laevis, also known as the African clawed frog.

In a medical context, Xenopus might be mentioned when discussing their use in research or as a model organism to study various biological processes or diseases.

"Xenopus proteins" refer to the proteins that are expressed or isolated from the Xenopus species, which are primarily used as model organisms in biological and biomedical research. The most commonly used Xenopus species for research are the African clawed frogs, Xenopus laevis and Xenopus tropicalis. These proteins play crucial roles in various cellular processes and functions, and they serve as valuable tools to study different aspects of molecular biology, developmental biology, genetics, and biochemistry.

Some examples of Xenopus proteins that are widely studied include:

1. Xenopus Histones: These are the proteins that package DNA into nucleosomes, which are the fundamental units of chromatin in eukaryotic cells. They play a significant role in gene regulation and epigenetic modifications.
2. Xenopus Cyclins and Cyclin-dependent kinases (CDKs): These proteins regulate the cell cycle and control cell division, differentiation, and apoptosis.
3. Xenopus Transcription factors: These proteins bind to specific DNA sequences and regulate gene expression during development and in response to various stimuli.
4. Xenopus Signaling molecules: These proteins are involved in intracellular signaling pathways that control various cellular processes, such as cell growth, differentiation, migration, and survival.
5. Xenopus Cytoskeletal proteins: These proteins provide structural support to the cells and regulate their shape, motility, and organization.
6. Xenopus Enzymes: These proteins catalyze various biochemical reactions in the cell, such as metabolic pathways, DNA replication, transcription, and translation.

Overall, Xenopus proteins are essential tools for understanding fundamental biological processes and have contributed significantly to our current knowledge of molecular biology, genetics, and developmental biology.

An oocyte, also known as an egg cell or female gamete, is a large specialized cell found in the ovary of female organisms. It contains half the number of chromosomes as a normal diploid cell, as it is the product of meiotic division. Oocytes are surrounded by follicle cells and are responsible for the production of female offspring upon fertilization with sperm. The term "oocyte" specifically refers to the immature egg cell before it reaches full maturity and is ready for fertilization, at which point it is referred to as an ovum or egg.

A nonmammalian embryo refers to the developing organism in animals other than mammals, from the fertilized egg (zygote) stage until hatching or birth. In nonmammalian species, the developmental stages and terminology differ from those used in mammals. The term "embryo" is generally applied to the developing organism up until a specific stage of development that is characterized by the formation of major organs and structures. After this point, the developing organism is referred to as a "larva," "juvenile," or other species-specific terminology.

The study of nonmammalian embryos has played an important role in our understanding of developmental biology and evolutionary developmental biology (evo-devo). By comparing the developmental processes across different animal groups, researchers can gain insights into the evolutionary origins and diversification of body plans and structures. Additionally, nonmammalian embryos are often used as model systems for studying basic biological processes, such as cell division, gene regulation, and pattern formation.

Biological metamorphosis is a complex process of transformation that certain organisms undergo during their development from embryo to adult. This process involves profound changes in form, function, and structure of the organism, often including modifications of various body parts, reorganization of internal organs, and changes in physiology.

In metamorphosis, a larval or juvenile form of an animal is significantly different from its adult form, both morphologically and behaviorally. This phenomenon is particularly common in insects, amphibians, and some fish and crustaceans. The most well-known examples include the transformation of a caterpillar into a butterfly or a tadpole into a frog.

The mechanisms that drive metamorphosis are regulated by hormonal signals and genetic programs. In many cases, metamorphosis is triggered by environmental factors such as temperature, moisture, or food availability, which interact with the organism's internal developmental cues to initiate the transformation. The process of metamorphosis allows these organisms to exploit different ecological niches at different stages of their lives and contributes to their evolutionary success.

An ovum is the female reproductive cell, or gamete, produced in the ovaries. It is also known as an egg cell and is released from the ovary during ovulation. When fertilized by a sperm, it becomes a zygote, which can develop into a fetus. The ovum contains half the genetic material necessary to create a new individual.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

A gastrula is a stage in the early development of many animals, including humans, that occurs following fertilization and cleavage of the zygote. During this stage, the embryo undergoes a process called gastrulation, which involves a series of cell movements that reorganize the embryo into three distinct layers: the ectoderm, mesoderm, and endoderm. These germ layers give rise to all the different tissues and organs in the developing organism.

The gastrula is characterized by the presence of a central cavity called the archenteron, which will eventually become the gut or gastrointestinal tract. The opening of the archenteron is called the blastopore, which will give rise to either the mouth or anus, depending on the animal group.

In summary, a gastrula is a developmental stage in which an embryo undergoes gastrulation to form three germ layers and a central cavity, which will eventually develop into various organs and tissues of the body.

Microinjection is a medical technique that involves the use of a fine, precise needle to inject small amounts of liquid or chemicals into microscopic structures, cells, or tissues. This procedure is often used in research settings to introduce specific substances into individual cells for study purposes, such as introducing DNA or RNA into cell nuclei to manipulate gene expression.

In clinical settings, microinjections may be used in various medical and cosmetic procedures, including:

1. Intracytoplasmic Sperm Injection (ICSI): A type of assisted reproductive technology where a single sperm is injected directly into an egg to increase the chances of fertilization during in vitro fertilization (IVF) treatments.
2. Botulinum Toxin Injections: Microinjections of botulinum toxin (Botox, Dysport, or Xeomin) are used for cosmetic purposes to reduce wrinkles and fine lines by temporarily paralyzing the muscles responsible for their formation. They can also be used medically to treat various neuromuscular disorders, such as migraines, muscle spasticity, and excessive sweating (hyperhidrosis).
3. Drug Delivery: Microinjections may be used to deliver drugs directly into specific tissues or organs, bypassing the systemic circulation and potentially reducing side effects. This technique can be particularly useful in treating localized pain, delivering growth factors for tissue regeneration, or administering chemotherapy agents directly into tumors.
4. Gene Therapy: Microinjections of genetic material (DNA or RNA) can be used to introduce therapeutic genes into cells to treat various genetic disorders or diseases, such as cystic fibrosis, hemophilia, or cancer.

Overall, microinjection is a highly specialized and precise technique that allows for the targeted delivery of substances into small structures, cells, or tissues, with potential applications in research, medical diagnostics, and therapeutic interventions.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

A larva is a distinct stage in the life cycle of various insects, mites, and other arthropods during which they undergo significant metamorphosis before becoming adults. In a medical context, larvae are known for their role in certain parasitic infections. Specifically, some helminth (parasitic worm) species use larval forms to infect human hosts. These invasions may lead to conditions such as cutaneous larva migrans, visceral larva migrans, or gnathostomiasis, depending on the specific parasite involved and the location of the infection within the body.

The larval stage is characterized by its markedly different morphology and behavior compared to the adult form. Larvae often have a distinct appearance, featuring unsegmented bodies, simple sense organs, and undeveloped digestive systems. They are typically adapted for a specific mode of life, such as free-living or parasitic existence, and rely on external sources of nutrition for their development.

In the context of helminth infections, larvae may be transmitted to humans through various routes, including ingestion of contaminated food or water, direct skin contact with infective stages, or transmission via an intermediate host (such as a vector). Once inside the human body, these parasitic larvae can cause tissue damage and provoke immune responses, leading to the clinical manifestations of disease.

It is essential to distinguish between the medical definition of 'larva' and its broader usage in biology and zoology. In those fields, 'larva' refers to any juvenile form that undergoes metamorphosis before reaching adulthood, regardless of whether it is parasitic or not.

Developmental gene expression regulation refers to the processes that control the activation or repression of specific genes during embryonic and fetal development. These regulatory mechanisms ensure that genes are expressed at the right time, in the right cells, and at appropriate levels to guide proper growth, differentiation, and morphogenesis of an organism.

Developmental gene expression regulation is a complex and dynamic process involving various molecular players, such as transcription factors, chromatin modifiers, non-coding RNAs, and signaling molecules. These regulators can interact with cis-regulatory elements, like enhancers and promoters, to fine-tune the spatiotemporal patterns of gene expression during development.

Dysregulation of developmental gene expression can lead to various congenital disorders and developmental abnormalities. Therefore, understanding the principles and mechanisms governing developmental gene expression regulation is crucial for uncovering the etiology of developmental diseases and devising potential therapeutic strategies.

Molecular cloning is a laboratory technique used to create multiple copies of a specific DNA sequence. This process involves several steps:

1. Isolation: The first step in molecular cloning is to isolate the DNA sequence of interest from the rest of the genomic DNA. This can be done using various methods such as PCR (polymerase chain reaction), restriction enzymes, or hybridization.
2. Vector construction: Once the DNA sequence of interest has been isolated, it must be inserted into a vector, which is a small circular DNA molecule that can replicate independently in a host cell. Common vectors used in molecular cloning include plasmids and phages.
3. Transformation: The constructed vector is then introduced into a host cell, usually a bacterial or yeast cell, through a process called transformation. This can be done using various methods such as electroporation or chemical transformation.
4. Selection: After transformation, the host cells are grown in selective media that allow only those cells containing the vector to grow. This ensures that the DNA sequence of interest has been successfully cloned into the vector.
5. Amplification: Once the host cells have been selected, they can be grown in large quantities to amplify the number of copies of the cloned DNA sequence.

Molecular cloning is a powerful tool in molecular biology and has numerous applications, including the production of recombinant proteins, gene therapy, functional analysis of genes, and genetic engineering.

Vitellogenins are a group of precursor proteins that are synthesized in the liver and subsequently transported to the ovaries, where they are taken up by developing oocytes. Once inside the oocyte, vitellogenins are cleaved into smaller proteins called lipovitellins and phosvitins, which play a crucial role in providing nutrients and energy to the developing embryo.

Vitellogenins are found in many oviparous species, including birds, reptiles, amphibians, fish, and some invertebrates. They are typically composed of several domains, including a large N-terminal domain that is rich in acidic amino acids, a central von Willebrand factor type D domain, and a C-terminal domain that contains multiple repeat units.

In addition to their role in egg development, vitellogenins have also been implicated in various physiological processes, such as immune function, stress response, and metal homeostasis. Moreover, the levels of vitellogenin in the blood can serve as a biomarker for environmental exposure to estrogenic compounds, as these chemicals can induce the synthesis of vitellogenins in male and juvenile animals.

Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.

A blastula is a stage in the early development of many animals, including mammals. It is a hollow ball of cells that forms as a result of cleavage, which is the process of cell division during embryonic development. The blastula is typically characterized by the presence of a fluid-filled cavity called the blastocoel, which is surrounded by a single layer of cells known as the blastoderm.

In mammals, the blastula stage follows the morula stage, which is a solid mass of cells that results from cleavage of the fertilized egg. During further cell division and rearrangement, the cells in the morula become organized into an inner cell mass and an outer layer of cells, called the trophoblast. The inner cell mass will eventually give rise to the embryo proper, while the trophoblast will contribute to the formation of the placenta.

As the morula continues to divide and expand, it forms a cavity within the inner cell mass, which becomes the blastocoel. The single layer of cells surrounding the blastocoel is called the blastoderm. At this stage, the blastula is capable of further development through a process called gastrulation, during which the three germ layers of the embryo (ectoderm, mesoderm, and endoderm) are formed.

It's important to note that not all animals go through a blastula stage in their development. Some animals, such as insects and nematodes, have different patterns of early development that do not include a blastula stage.

Complementary RNA refers to a single-stranded RNA molecule that is complementary to another RNA or DNA sequence in terms of base pairing. In other words, it is the nucleic acid strand that can form a double-stranded structure with another strand through hydrogen bonding between complementary bases (A-U and G-C). Complementary RNAs play crucial roles in various biological processes such as transcription, translation, and gene regulation. For example, during transcription, the DNA template strand serves as the template for the synthesis of a complementary RNA strand, known as the primary transcript or pre-mRNA. This pre-mRNA then undergoes processing to remove non-coding sequences and generate a mature mRNA that is complementary to the DNA template strand. Complementary RNAs are also involved in RNA interference (RNAi), where small interfering RNAs (siRNAs) or microRNAs (miRNAs) bind to complementary sequences in target mRNAs, leading to their degradation or translation inhibition.

In situ hybridization (ISH) is a molecular biology technique used to detect and localize specific nucleic acid sequences, such as DNA or RNA, within cells or tissues. This technique involves the use of a labeled probe that is complementary to the target nucleic acid sequence. The probe can be labeled with various types of markers, including radioisotopes, fluorescent dyes, or enzymes.

During the ISH procedure, the labeled probe is hybridized to the target nucleic acid sequence in situ, meaning that the hybridization occurs within the intact cells or tissues. After washing away unbound probe, the location of the labeled probe can be visualized using various methods depending on the type of label used.

In situ hybridization has a wide range of applications in both research and diagnostic settings, including the detection of gene expression patterns, identification of viral infections, and diagnosis of genetic disorders.

Sequence homology, amino acid, refers to the similarity in the order of amino acids in a protein or a portion of a protein between two or more species. This similarity can be used to infer evolutionary relationships and functional similarities between proteins. The higher the degree of sequence homology, the more likely it is that the proteins are related and have similar functions. Sequence homology can be determined through various methods such as pairwise alignment or multiple sequence alignment, which compare the sequences and calculate a score based on the number and type of matching amino acids.

Embryonic induction is a process that occurs during the development of a multicellular organism, where one group of cells in the embryo signals and influences the developmental fate of another group of cells. This interaction leads to the formation of specific structures or organs in the developing embryo. The signaling cells that initiate the process are called organizers, and they release signaling molecules known as morphogens that bind to receptors on the target cells and trigger a cascade of intracellular signals that ultimately lead to changes in gene expression and cell fate. Embryonic induction is a crucial step in the development of complex organisms and plays a key role in establishing the body plan and organizing the different tissues and organs in the developing embryo.

In medical and embryological terms, the mesoderm is one of the three primary germ layers in the very early stages of embryonic development. It forms between the ectoderm and endoderm during gastrulation, and it gives rise to a wide variety of cell types, tissues, and organs in the developing embryo.

The mesoderm contributes to the formation of structures such as:

1. The connective tissues (including tendons, ligaments, and most of the bones)
2. Muscular system (skeletal, smooth, and cardiac muscles)
3. Circulatory system (heart, blood vessels, and blood cells)
4. Excretory system (kidneys and associated structures)
5. Reproductive system (gonads, including ovaries and testes)
6. Dermis of the skin
7. Parts of the eye and inner ear
8. Several organs in the urogenital system

Dysfunctions or abnormalities in mesoderm development can lead to various congenital disorders and birth defects, highlighting its importance during embryogenesis.

Ectoderm is the outermost of the three primary germ layers in a developing embryo, along with the endoderm and mesoderm. The ectoderm gives rise to the outer covering of the body, including the skin, hair, nails, glands, and the nervous system, which includes the brain, spinal cord, and peripheral nerves. It also forms the lining of the mouth, anus, nose, and ears. Essentially, the ectoderm is responsible for producing all the epidermal structures and the neural crest cells that contribute to various derivatives such as melanocytes, adrenal medulla, smooth muscle, and peripheral nervous system components.

Oogenesis is the biological process of formation and maturation of female gametes, or ova or egg cells, in the ovary. It begins during fetal development and continues throughout a woman's reproductive years. The process involves the division and differentiation of a germ cell (oogonium) into an immature ovum (oocyte), which then undergoes meiotic division to form a mature ovum capable of being fertilized by sperm.

The main steps in oogenesis include:

1. Multiplication phase: The oogonia divide mitotically to increase their number.
2. Growth phase: One of the oogonia becomes primary oocyte and starts to grow, accumulating nutrients and organelles required for future development.
3. First meiotic division: The primary oocyte undergoes an incomplete first meiotic division, resulting in two haploid cells - a secondary oocyte and a smaller cell called the first polar body. This division is arrested in prophase I until puberty.
4. Second meiotic division: At ovulation or just before fertilization, the secondary oocyte completes the second meiotic division, producing another small cell, the second polar body, and a mature ovum (egg) with 23 chromosomes.
5. Fertilization: The mature ovum can be fertilized by a sperm, restoring the normal diploid number of chromosomes in the resulting zygote.

Oogenesis is a complex and highly regulated process that involves various hormonal signals and cellular interactions to ensure proper development and maturation of female gametes for successful reproduction.

Cell extracts refer to the mixture of cellular components that result from disrupting or breaking open cells. The process of obtaining cell extracts is called cell lysis. Cell extracts can contain various types of molecules, such as proteins, nucleic acids (DNA and RNA), carbohydrates, lipids, and metabolites, depending on the methods used for cell disruption and extraction.

Cell extracts are widely used in biochemical and molecular biology research to study various cellular processes and pathways. For example, cell extracts can be used to measure enzyme activities, analyze protein-protein interactions, characterize gene expression patterns, and investigate metabolic pathways. In some cases, specific cellular components can be purified from the cell extracts for further analysis or application, such as isolating pure proteins or nucleic acids.

It is important to note that the composition of cell extracts may vary depending on the type of cells, the growth conditions, and the methods used for cell disruption and extraction. Therefore, it is essential to optimize the experimental conditions to obtain representative and meaningful results from cell extract studies.

Complementary DNA (cDNA) is a type of DNA that is synthesized from a single-stranded RNA molecule through the process of reverse transcription. In this process, the enzyme reverse transcriptase uses an RNA molecule as a template to synthesize a complementary DNA strand. The resulting cDNA is therefore complementary to the original RNA molecule and is a copy of its coding sequence, but it does not contain non-coding regions such as introns that are present in genomic DNA.

Complementary DNA is often used in molecular biology research to study gene expression, protein function, and other genetic phenomena. For example, cDNA can be used to create cDNA libraries, which are collections of cloned cDNA fragments that represent the expressed genes in a particular cell type or tissue. These libraries can then be screened for specific genes or gene products of interest. Additionally, cDNA can be used to produce recombinant proteins in heterologous expression systems, allowing researchers to study the structure and function of proteins that may be difficult to express or purify from their native sources.

Deoxyribonucleic acid (DNA) is the genetic material present in the cells of organisms where it is responsible for the storage and transmission of hereditary information. DNA is a long molecule that consists of two strands coiled together to form a double helix. Each strand is made up of a series of four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - that are linked together by phosphate and sugar groups. The sequence of these bases along the length of the molecule encodes genetic information, with A always pairing with T and C always pairing with G. This base-pairing allows for the replication and transcription of DNA, which are essential processes in the functioning and reproduction of all living organisms.

Genetic transcription is the process by which the information in a strand of DNA is used to create a complementary RNA molecule. This process is the first step in gene expression, where the genetic code in DNA is converted into a form that can be used to produce proteins or functional RNAs.

During transcription, an enzyme called RNA polymerase binds to the DNA template strand and reads the sequence of nucleotide bases. As it moves along the template, it adds complementary RNA nucleotides to the growing RNA chain, creating a single-stranded RNA molecule that is complementary to the DNA template strand. Once transcription is complete, the RNA molecule may undergo further processing before it can be translated into protein or perform its functional role in the cell.

Transcription can be either "constitutive" or "regulated." Constitutive transcription occurs at a relatively constant rate and produces essential proteins that are required for basic cellular functions. Regulated transcription, on the other hand, is subject to control by various intracellular and extracellular signals, allowing cells to respond to changing environmental conditions or developmental cues.

Melanophores are specialized pigment-containing cells found in various organisms, including vertebrates and some invertebrates. In humans and other mammals, melanophores are primarily located within the skin's dermal layer and are part of the larger group of chromatophores.

Melanophores contain melanosomes, which are organelles that store and transport the pigment melanin. These cells play a crucial role in determining the coloration of an individual's skin, hair, and eyes by producing, storing, and distributing melanin granules within their cytoplasm.

In response to hormonal signals or neural stimulation, melanophores can undergo changes in the distribution of melanosomes, leading to variations in color intensity. This process is known as melanin dispersion or aggregation and is responsible for various physiological responses, such as skin tanning upon exposure to sunlight or the color-changing abilities observed in some animals like chameleons and cuttlefish.

It's important to note that while humans do not have the ability to change their skin color rapidly like some other animals, melanophores still play a significant role in protecting our skin from harmful ultraviolet radiation by producing melanin, which helps absorb and dissipate this energy, reducing damage to skin cells.

5S Ribosomal RNA (5S rRNA) is a type of ribosomal RNA molecule that is a component of the large subunit of the ribosome, a complex molecular machine found in the cells of all living organisms. The "5S" refers to its sedimentation coefficient, a measure of its rate of sedimentation in an ultracentrifuge, which is 5S.

In prokaryotic cells, there are typically one or two copies of 5S rRNA molecules per ribosome, while in eukaryotic cells, there are three to four copies per ribosome. The 5S rRNA plays a structural role in the ribosome and is also involved in the process of protein synthesis, working together with other ribosomal components to translate messenger RNA (mRNA) into proteins.

The 5S rRNA molecule is relatively small, ranging from 100 to 150 nucleotides in length, and has a characteristic secondary structure that includes several stem-loop structures. The sequence and structure of the 5S rRNA are highly conserved across different species, making it a useful tool for studying evolutionary relationships between organisms.

Transcription Factor IIIA (TFIIIA) is a specific type of transcription factor that plays a crucial role in the initiation of gene transcription, particularly for 5S ribosomal RNA (rRNA) genes. It is a complex of proteins, including the TATA-binding protein (TBP) and several other factors. TFIIIA recognizes and binds to the internal control region (ICR) of the 5S rRNA gene, helping to assemble the transcription preinitiation complex and promoting the accurate initiation of transcription by RNA polymerase III.

"Body patterning" is a general term that refers to the process of forming and organizing various tissues and structures into specific patterns during embryonic development. This complex process involves a variety of molecular mechanisms, including gene expression, cell signaling, and cell-cell interactions. It results in the creation of distinct body regions, such as the head, trunk, and limbs, as well as the organization of internal organs and systems.

In medical terminology, "body patterning" may refer to specific developmental processes or abnormalities related to embryonic development. For example, in genetic disorders such as Poland syndrome or Holt-Oram syndrome, mutations in certain genes can lead to abnormal body patterning, resulting in the absence or underdevelopment of certain muscles, bones, or other structures.

It's important to note that "body patterning" is not a formal medical term with a specific definition, but rather a general concept used in developmental biology and genetics.

The nervous system is a complex, highly organized network of specialized cells called neurons and glial cells that communicate with each other via electrical and chemical signals to coordinate various functions and activities in the body. It consists of two main parts: the central nervous system (CNS), including the brain and spinal cord, and the peripheral nervous system (PNS), which includes all the nerves and ganglia outside the CNS.

The primary function of the nervous system is to receive, process, and integrate information from both internal and external environments and then respond by generating appropriate motor outputs or behaviors. This involves sensing various stimuli through specialized receptors, transmitting this information through afferent neurons to the CNS for processing, integrating this information with other inputs and memories, making decisions based on this processed information, and finally executing responses through efferent neurons that control effector organs such as muscles and glands.

The nervous system can be further divided into subsystems based on their functions, including the somatic nervous system, which controls voluntary movements and reflexes; the autonomic nervous system, which regulates involuntary physiological processes like heart rate, digestion, and respiration; and the enteric nervous system, which is a specialized subset of the autonomic nervous system that controls gut functions. Overall, the nervous system plays a critical role in maintaining homeostasis, regulating behavior, and enabling cognition and consciousness.

Carrier proteins, also known as transport proteins, are a type of protein that facilitates the movement of molecules across cell membranes. They are responsible for the selective and active transport of ions, sugars, amino acids, and other molecules from one side of the membrane to the other, against their concentration gradient. This process requires energy, usually in the form of ATP (adenosine triphosphate).

Carrier proteins have a specific binding site for the molecule they transport, and undergo conformational changes upon binding, which allows them to move the molecule across the membrane. Once the molecule has been transported, the carrier protein returns to its original conformation, ready to bind and transport another molecule.

Carrier proteins play a crucial role in maintaining the balance of ions and other molecules inside and outside of cells, and are essential for many physiological processes, including nerve impulse transmission, muscle contraction, and nutrient uptake.

Morphogenesis is a term used in developmental biology and refers to the process by which cells give rise to tissues and organs with specific shapes, structures, and patterns during embryonic development. This process involves complex interactions between genes, cells, and the extracellular environment that result in the coordinated movement and differentiation of cells into specialized functional units.

Morphogenesis is a dynamic and highly regulated process that involves several mechanisms, including cell proliferation, death, migration, adhesion, and differentiation. These processes are controlled by genetic programs and signaling pathways that respond to environmental cues and regulate the behavior of individual cells within a developing tissue or organ.

The study of morphogenesis is important for understanding how complex biological structures form during development and how these processes can go awry in disease states such as cancer, birth defects, and degenerative disorders.

Nucleoplasmin is a major protein component of the nucleoplasm, the liquid matrix inside the nucleus of a eukaryotic cell. It plays a crucial role in the organization and dynamics of chromatin, which is the complex of DNA, RNA, and proteins that make up the chromosomes. Specifically, nucleoplasmin has high affinity for histone proteins, which are the core components of nucleosomes, the basic unit of chromatin structure. By binding to histones, nucleoplasmin helps to regulate the assembly and disassembly of nucleosomes during processes such as DNA replication, repair, and transcription. Additionally, nucleoplasmin has been implicated in the intracellular transport of proteins and RNA, contributing to the overall maintenance and function of the nuclear environment.

RNA (Ribonucleic Acid) is a single-stranded, linear polymer of ribonucleotides. It is a nucleic acid present in the cells of all living organisms and some viruses. RNAs play crucial roles in various biological processes such as protein synthesis, gene regulation, and cellular signaling. There are several types of RNA including messenger RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), small nuclear RNA (snRNA), microRNA (miRNA), and long non-coding RNA (lncRNA). These RNAs differ in their structure, function, and location within the cell.

Transcription factors are proteins that play a crucial role in regulating gene expression by controlling the transcription of DNA to messenger RNA (mRNA). They function by binding to specific DNA sequences, known as response elements, located in the promoter region or enhancer regions of target genes. This binding can either activate or repress the initiation of transcription, depending on the properties and interactions of the particular transcription factor. Transcription factors often act as part of a complex network of regulatory proteins that determine the precise spatiotemporal patterns of gene expression during development, differentiation, and homeostasis in an organism.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Genetically modified animals (GMAs) are those whose genetic makeup has been altered using biotechnological techniques. This is typically done by introducing one or more genes from another species into the animal's genome, resulting in a new trait or characteristic that does not naturally occur in that species. The introduced gene is often referred to as a transgene.

The process of creating GMAs involves several steps:

1. Isolation: The desired gene is isolated from the DNA of another organism.
2. Transfer: The isolated gene is transferred into the target animal's cells, usually using a vector such as a virus or bacterium.
3. Integration: The transgene integrates into the animal's chromosome, becoming a permanent part of its genetic makeup.
4. Selection: The modified cells are allowed to multiply, and those that contain the transgene are selected for further growth and development.
5. Breeding: The genetically modified individuals are bred to produce offspring that carry the desired trait.

GMAs have various applications in research, agriculture, and medicine. In research, they can serve as models for studying human diseases or testing new therapies. In agriculture, GMAs can be developed to exhibit enhanced growth rates, improved disease resistance, or increased nutritional value. In medicine, GMAs may be used to produce pharmaceuticals or other therapeutic agents within their bodies.

Examples of genetically modified animals include mice with added genes for specific proteins that make them useful models for studying human diseases, goats that produce a human protein in their milk to treat hemophilia, and pigs with enhanced resistance to certain viruses that could potentially be used as organ donors for humans.

It is important to note that the use of genetically modified animals raises ethical concerns related to animal welfare, environmental impact, and potential risks to human health. These issues must be carefully considered and addressed when developing and implementing GMA technologies.

Ribosomal RNA (rRNA) is a type of RNA molecule that is a key component of ribosomes, which are the cellular structures where protein synthesis occurs in cells. In ribosomes, rRNA plays a crucial role in the process of translation, where genetic information from messenger RNA (mRNA) is translated into proteins.

Ribosomal RNA is synthesized in the nucleus and then transported to the cytoplasm, where it assembles with ribosomal proteins to form ribosomes. Within the ribosome, rRNA provides a structural framework for the assembly of the ribosome and also plays an active role in catalyzing the formation of peptide bonds between amino acids during protein synthesis.

There are several different types of rRNA molecules, including 5S, 5.8S, 18S, and 28S rRNA, which vary in size and function. These rRNA molecules are highly conserved across different species, indicating their essential role in protein synthesis and cellular function.

Biological transport refers to the movement of molecules, ions, or solutes across biological membranes or through cells in living organisms. This process is essential for maintaining homeostasis, regulating cellular functions, and enabling communication between cells. There are two main types of biological transport: passive transport and active transport.

Passive transport does not require the input of energy and includes:

1. Diffusion: The random movement of molecules from an area of high concentration to an area of low concentration until equilibrium is reached.
2. Osmosis: The diffusion of solvent molecules (usually water) across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
3. Facilitated diffusion: The assisted passage of polar or charged substances through protein channels or carriers in the cell membrane, which increases the rate of diffusion without consuming energy.

Active transport requires the input of energy (in the form of ATP) and includes:

1. Primary active transport: The direct use of ATP to move molecules against their concentration gradient, often driven by specific transport proteins called pumps.
2. Secondary active transport: The coupling of the movement of one substance down its electrochemical gradient with the uphill transport of another substance, mediated by a shared transport protein. This process is also known as co-transport or counter-transport.

Gene expression is the process by which the information encoded in a gene is used to synthesize a functional gene product, such as a protein or RNA molecule. This process involves several steps: transcription, RNA processing, and translation. During transcription, the genetic information in DNA is copied into a complementary RNA molecule, known as messenger RNA (mRNA). The mRNA then undergoes RNA processing, which includes adding a cap and tail to the mRNA and splicing out non-coding regions called introns. The resulting mature mRNA is then translated into a protein on ribosomes in the cytoplasm through the process of translation.

The regulation of gene expression is a complex and highly controlled process that allows cells to respond to changes in their environment, such as growth factors, hormones, and stress signals. This regulation can occur at various stages of gene expression, including transcriptional activation or repression, RNA processing, mRNA stability, and translation. Dysregulation of gene expression has been implicated in many diseases, including cancer, genetic disorders, and neurological conditions.

In genetics, sequence alignment is the process of arranging two or more DNA, RNA, or protein sequences to identify regions of similarity or homology between them. This is often done using computational methods to compare the nucleotide or amino acid sequences and identify matching patterns, which can provide insight into evolutionary relationships, functional domains, or potential genetic disorders. The alignment process typically involves adjusting gaps and mismatches in the sequences to maximize the similarity between them, resulting in an aligned sequence that can be visually represented and analyzed.

In the context of human anatomy, the term "tail" is not used to describe any part of the body. Humans are considered tailless primates, and there is no structure or feature that corresponds directly to the tails found in many other animals.

However, there are some medical terms related to the lower end of the spine that might be confused with a tail:

1. Coccyx (Tailbone): The coccyx is a small triangular bone at the very bottom of the spinal column, formed by the fusion of several rudimentary vertebrae. It's also known as the tailbone because it resembles the end of an animal's tail in its location and appearance.
2. Cauda Equina (Horse's Tail): The cauda equina is a bundle of nerve roots at the lower end of the spinal cord, just above the coccyx. It got its name because it looks like a horse's tail due to the numerous rootlets radiating from the conus medullaris (the tapering end of the spinal cord).

These two structures are not tails in the traditional sense but rather medical terms related to the lower end of the human spine.

The notochord is a flexible, rod-shaped structure that is present in the embryos of chordates, including humans. It is composed of cells called chordocytes and is surrounded by a sheath. The notochord runs along the length of the body, providing support and flexibility. In human embryos, the notochord eventually becomes part of the discs between the vertebrae in the spine. An abnormal or absent notochord can lead to developmental problems with the spine and nervous system.

Membrane potential is the electrical potential difference across a cell membrane, typically for excitable cells such as nerve and muscle cells. It is the difference in electric charge between the inside and outside of a cell, created by the selective permeability of the cell membrane to different ions. The resting membrane potential of a typical animal cell is around -70 mV, with the interior being negative relative to the exterior. This potential is generated and maintained by the active transport of ions across the membrane, primarily through the action of the sodium-potassium pump. Membrane potentials play a crucial role in many physiological processes, including the transmission of nerve impulses and the contraction of muscle cells.

Protein biosynthesis is the process by which cells generate new proteins. It involves two major steps: transcription and translation. Transcription is the process of creating a complementary RNA copy of a sequence of DNA. This RNA copy, or messenger RNA (mRNA), carries the genetic information to the site of protein synthesis, the ribosome. During translation, the mRNA is read by transfer RNA (tRNA) molecules, which bring specific amino acids to the ribosome based on the sequence of nucleotides in the mRNA. The ribosome then links these amino acids together in the correct order to form a polypeptide chain, which may then fold into a functional protein. Protein biosynthesis is essential for the growth and maintenance of all living organisms.

Recombinant proteins are artificially created proteins produced through the use of recombinant DNA technology. This process involves combining DNA molecules from different sources to create a new set of genes that encode for a specific protein. The resulting recombinant protein can then be expressed, purified, and used for various applications in research, medicine, and industry.

Recombinant proteins are widely used in biomedical research to study protein function, structure, and interactions. They are also used in the development of diagnostic tests, vaccines, and therapeutic drugs. For example, recombinant insulin is a common treatment for diabetes, while recombinant human growth hormone is used to treat growth disorders.

The production of recombinant proteins typically involves the use of host cells, such as bacteria, yeast, or mammalian cells, which are engineered to express the desired protein. The host cells are transformed with a plasmid vector containing the gene of interest, along with regulatory elements that control its expression. Once the host cells are cultured and the protein is expressed, it can be purified using various chromatography techniques.

Overall, recombinant proteins have revolutionized many areas of biology and medicine, enabling researchers to study and manipulate proteins in ways that were previously impossible.

The cell nucleus is a membrane-bound organelle found in the eukaryotic cells (cells with a true nucleus). It contains most of the cell's genetic material, organized as DNA molecules in complex with proteins, RNA molecules, and histones to form chromosomes.

The primary function of the cell nucleus is to regulate and control the activities of the cell, including growth, metabolism, protein synthesis, and reproduction. It also plays a crucial role in the process of mitosis (cell division) by separating and protecting the genetic material during this process. The nuclear membrane, or nuclear envelope, surrounding the nucleus is composed of two lipid bilayers with numerous pores that allow for the selective transport of molecules between the nucleoplasm (nucleus interior) and the cytoplasm (cell exterior).

The cell nucleus is a vital structure in eukaryotic cells, and its dysfunction can lead to various diseases, including cancer and genetic disorders.

Activins are a type of protein that belongs to the transforming growth factor-beta (TGF-β) superfamily. They are produced and released by various cells in the body, including those in the ovaries, testes, pituitary gland, and other tissues. Activins play important roles in regulating several biological processes, such as cell growth, differentiation, and apoptosis (programmed cell death).

Activins bind to specific receptors on the surface of cells, leading to the activation of intracellular signaling pathways that control gene expression. They are particularly well-known for their role in reproductive biology, where they help regulate follicle stimulation and hormone production in the ovaries and testes. Activins also have been implicated in various disease processes, including cancer, fibrosis, and inflammation.

There are three main isoforms of activin in humans: activin A, activin B, and inhibin A. While activins and inhibins share similar structures and functions, they have opposite effects on the activity of the pituitary gland. Activins stimulate the production of follicle-stimulating hormone (FSH), while inhibins suppress it. This delicate balance between activins and inhibins helps regulate reproductive function and other physiological processes in the body.

A symporter is a type of transmembrane protein that functions to transport two or more molecules or ions across a biological membrane in the same direction, simultaneously. This process is called co-transport and it is driven by the concentration gradient of one of the substrates, which is usually an ion such as sodium (Na+) or proton (H+).

Symporters are classified based on the type of energy that drives the transport process. Primary active transporters, such as symporters, use the energy from ATP hydrolysis or from the electrochemical gradient of ions to move substrates against their concentration gradient. In contrast, secondary active transporters use the energy stored in an existing electrochemical gradient of one substrate to drive the transport of another substrate against its own concentration gradient.

Symporters play important roles in various physiological processes, including nutrient uptake, neurotransmitter reuptake, and ion homeostasis. For example, the sodium-glucose transporter (SGLT) is a symporter that co-transports glucose and sodium ions across the intestinal epithelium and the renal proximal tubule, contributing to glucose absorption and regulation of blood glucose levels. Similarly, the dopamine transporter (DAT) is a symporter that co-transports dopamine and sodium ions back into presynaptic neurons, terminating the action of dopamine in the synapse.

Species specificity is a term used in the field of biology, including medicine, to refer to the characteristic of a biological entity (such as a virus, bacterium, or other microorganism) that allows it to interact exclusively or preferentially with a particular species. This means that the biological entity has a strong affinity for, or is only able to infect, a specific host species.

For example, HIV is specifically adapted to infect human cells and does not typically infect other animal species. Similarly, some bacterial toxins are species-specific and can only affect certain types of animals or humans. This concept is important in understanding the transmission dynamics and host range of various pathogens, as well as in developing targeted therapies and vaccines.

Amphibians are a class of cold-blooded vertebrates that include frogs, toads, salamanders, newts, and caecilians. They are characterized by their four-limbed body structure, moist skin, and double circulation system with three-chambered hearts. Amphibians are unique because they have a life cycle that involves two distinct stages: an aquatic larval stage (usually as a tadpole or larva) and a terrestrial adult stage. They typically start their lives in water, undergoing metamorphosis to develop lungs and legs for a land-dwelling existence. Many amphibians are also known for their complex reproductive behaviors and vocalizations.

Sequence homology in nucleic acids refers to the similarity or identity between the nucleotide sequences of two or more DNA or RNA molecules. It is often used as a measure of biological relationship between genes, organisms, or populations. High sequence homology suggests a recent common ancestry or functional constraint, while low sequence homology may indicate a more distant relationship or different functions.

Nucleic acid sequence homology can be determined by various methods such as pairwise alignment, multiple sequence alignment, and statistical analysis. The degree of homology is typically expressed as a percentage of identical or similar nucleotides in a given window of comparison.

It's important to note that the interpretation of sequence homology depends on the biological context and the evolutionary distance between the sequences compared. Therefore, functional and experimental validation is often necessary to confirm the significance of sequence homology.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Electrophysiology is a branch of medicine that deals with the electrical activities of the body, particularly the heart. In a medical context, electrophysiology studies (EPS) are performed to assess abnormal heart rhythms (arrhythmias) and to evaluate the effectiveness of certain treatments, such as medication or pacemakers.

During an EPS, electrode catheters are inserted into the heart through blood vessels in the groin or neck. These catheters can record the electrical activity of the heart and stimulate it to help identify the source of the arrhythmia. The information gathered during the study can help doctors determine the best course of treatment for each patient.

In addition to cardiac electrophysiology, there are also other subspecialties within electrophysiology, such as neuromuscular electrophysiology, which deals with the electrical activity of the nervous system and muscles.

Maturation-Promoting Factor (MPF) is not a medical term per se, but it is commonly used in the field of cell biology and cancer research. MPF refers to a complex of two proteins that play a crucial role in regulating the cell cycle, specifically during the transition from the G2 phase to mitosis (M phase).

MPF is composed of a cyclin-dependent kinase (CDK1) and a regulatory subunit called cyclin B. During the late G2 phase, the levels of cyclin B increase, which leads to the activation of CDK1. Once activated, MPF triggers a series of events that promote mitosis, including chromosome condensation, nuclear envelope breakdown, and spindle formation.

In summary, Maturation-Promoting Factor (MPF) is a protein complex made up of CDK1 and cyclin B, which regulates the transition from the G2 phase to mitosis during the cell cycle.

"Poly A" is an abbreviation for "poly(A) tail" or "polyadenylation." It refers to the addition of multiple adenine (A) nucleotides to the 3' end of eukaryotic mRNA molecules during the process of transcription. This poly(A) tail plays a crucial role in various aspects of mRNA metabolism, including stability, transport, and translation. The length of the poly(A) tail can vary from around 50 to 250 nucleotides depending on the cell type and developmental stage.

A zygote is the initial cell formed when a sperm fertilizes an egg, also known as an oocyte. This occurs in the process of human reproduction and marks the beginning of a new genetic identity, containing 46 chromosomes - 23 from the sperm and 23 from the egg. The zygote starts the journey of cell division and growth, eventually developing into a blastocyst, then an embryo, and finally a fetus over the course of pregnancy.

Blastomeres are early stage embryonic cells that result from the initial rounds of cell division in a fertilized egg, also known as a zygote. These cells are typically smaller and have a more simple organization compared to more mature cells. They are important for the normal development of the embryo and contribute to the formation of the blastocyst, which is an early stage embryonic structure that will eventually give rise to the fetus. The process of cell division that produces blastomeres is called cleavage.

Homeodomain proteins are a group of transcription factors that play crucial roles in the development and differentiation of cells in animals and plants. They are characterized by the presence of a highly conserved DNA-binding domain called the homeodomain, which is typically about 60 amino acids long. The homeodomain consists of three helices, with the third helix responsible for recognizing and binding to specific DNA sequences.

Homeodomain proteins are involved in regulating gene expression during embryonic development, tissue maintenance, and organismal growth. They can act as activators or repressors of transcription, depending on the context and the presence of cofactors. Mutations in homeodomain proteins have been associated with various human diseases, including cancer, congenital abnormalities, and neurological disorders.

Some examples of homeodomain proteins include PAX6, which is essential for eye development, HOX genes, which are involved in body patterning, and NANOG, which plays a role in maintaining pluripotency in stem cells.

Egg proteins, also known as egg white proteins or ovalbumin, refer to the proteins found in egg whites. There are several different types of proteins found in egg whites, including:

1. Ovalbumin (54%): This is the major protein found in egg whites and is responsible for their white color. It has various functions such as providing nutrition, maintaining the structural integrity of the egg, and protecting the egg from bacteria.
2. Conalbumin (13%): Also known as ovotransferrin, this protein plays a role in the defense against microorganisms by binding to iron and making it unavailable for bacterial growth.
3. Ovomucoid (11%): This protein is resistant to digestion and helps protect the egg from being broken down by enzymes in the digestive tract of predators.
4. Lysozyme (3.5%): This protein has antibacterial properties and helps protect the egg from bacterial infection.
5. Globulins (4%): These are a group of simple proteins found in egg whites that have various functions such as providing nutrition, maintaining the structural integrity of the egg, and protecting the egg from bacteria.
6. Avidin (0.05%): This protein binds to biotin, a vitamin, making it unavailable for use by the body. However, cooking denatures avidin and makes the biotin available again.

Egg proteins are highly nutritious and contain all nine essential amino acids, making them a complete source of protein. They are also low in fat and cholesterol, making them a popular choice for those following a healthy diet.

A gene is a specific sequence of nucleotides in DNA that carries genetic information. Genes are the fundamental units of heredity and are responsible for the development and function of all living organisms. They code for proteins or RNA molecules, which carry out various functions within cells and are essential for the structure, function, and regulation of the body's tissues and organs.

Each gene has a specific location on a chromosome, and each person inherits two copies of every gene, one from each parent. Variations in the sequence of nucleotides in a gene can lead to differences in traits between individuals, including physical characteristics, susceptibility to disease, and responses to environmental factors.

Medical genetics is the study of genes and their role in health and disease. It involves understanding how genes contribute to the development and progression of various medical conditions, as well as identifying genetic risk factors and developing strategies for prevention, diagnosis, and treatment.

DNA-binding proteins are a type of protein that have the ability to bind to DNA (deoxyribonucleic acid), the genetic material of organisms. These proteins play crucial roles in various biological processes, such as regulation of gene expression, DNA replication, repair and recombination.

The binding of DNA-binding proteins to specific DNA sequences is mediated by non-covalent interactions, including electrostatic, hydrogen bonding, and van der Waals forces. The specificity of binding is determined by the recognition of particular nucleotide sequences or structural features of the DNA molecule.

DNA-binding proteins can be classified into several categories based on their structure and function, such as transcription factors, histones, and restriction enzymes. Transcription factors are a major class of DNA-binding proteins that regulate gene expression by binding to specific DNA sequences in the promoter region of genes and recruiting other proteins to modulate transcription. Histones are DNA-binding proteins that package DNA into nucleosomes, the basic unit of chromatin structure. Restriction enzymes are DNA-binding proteins that recognize and cleave specific DNA sequences, and are widely used in molecular biology research and biotechnology applications.

A plasmid is a small, circular, double-stranded DNA molecule that is separate from the chromosomal DNA of a bacterium or other organism. Plasmids are typically not essential for the survival of the organism, but they can confer beneficial traits such as antibiotic resistance or the ability to degrade certain types of pollutants.

Plasmids are capable of replicating independently of the chromosomal DNA and can be transferred between bacteria through a process called conjugation. They often contain genes that provide resistance to antibiotics, heavy metals, and other environmental stressors. Plasmids have also been engineered for use in molecular biology as cloning vectors, allowing scientists to replicate and manipulate specific DNA sequences.

Plasmids are important tools in genetic engineering and biotechnology because they can be easily manipulated and transferred between organisms. They have been used to produce vaccines, diagnostic tests, and genetically modified organisms (GMOs) for various applications, including agriculture, medicine, and industry.

Fertilization is the process by which a sperm cell (spermatozoon) penetrates and fuses with an egg cell (ovum), resulting in the formation of a zygote. This fusion of genetic material from both the male and female gametes initiates the development of a new organism. In human biology, fertilization typically occurs in the fallopian tube after sexual intercourse, when a single sperm out of millions is able to reach and penetrate the egg released from the ovary during ovulation. The successful fusion of these two gametes marks the beginning of pregnancy.

Nucleic acid hybridization is a process in molecular biology where two single-stranded nucleic acids (DNA, RNA) with complementary sequences pair together to form a double-stranded molecule through hydrogen bonding. The strands can be from the same type of nucleic acid or different types (i.e., DNA-RNA or DNA-cDNA). This process is commonly used in various laboratory techniques, such as Southern blotting, Northern blotting, polymerase chain reaction (PCR), and microarray analysis, to detect, isolate, and analyze specific nucleic acid sequences. The hybridization temperature and conditions are critical to ensure the specificity of the interaction between the two strands.

Gastrulation is a fundamental process in embryonic development, characterized by the transformation of a initially flat layer of cells called the blastula into a three-layered structure known as the gastrula. This complex series of cellular movements and rearrangements establishes the foundation for the formation of the three primary germ layers: the ectoderm, mesoderm, and endoderm. These germ layers further differentiate to give rise to all the diverse cell types and tissues in the developing organism, including the nervous system, muscles, bones, and internal organs.

The precise mechanisms of gastrulation vary among different animal groups; however, common features include:

1. Formation of a blastopore: A small indentation or opening that forms on the surface of the blastula, which eventually develops into the primitive gut or anus in the gastrula.
2. Invagination: The process by which cells at the blastopore fold inward and migrate towards the interior of the embryo, forming the endodermal layer.
3. Epiboly: A coordinated movement of cells that spreads over and encloses the yolk within the embryo, contributing to the formation of the ectodermal layer.
4. Delamination: The separation and migration of cells from the epiblast (the outer layer of the blastula) to form the mesodermal layer in between the ectoderm and endoderm.

Gastrulation is a critical period in embryonic development, as errors during this process can lead to severe congenital abnormalities or even embryonic lethality. A thorough understanding of gastrulation has important implications for regenerative medicine, stem cell research, and the study of evolutionary developmental biology (Evo-Devo).

Embryonic development is the series of growth and developmental stages that occur during the formation and early growth of the embryo. In humans, this stage begins at fertilization (when the sperm and egg cell combine) and continues until the end of the 8th week of pregnancy. During this time, the fertilized egg (now called a zygote) divides and forms a blastocyst, which then implants into the uterus. The cells in the blastocyst begin to differentiate and form the three germ layers: the ectoderm, mesoderm, and endoderm. These germ layers will eventually give rise to all of the different tissues and organs in the body.

Embryonic development is a complex and highly regulated process that involves the coordinated interaction of genetic and environmental factors. It is characterized by rapid cell division, migration, and differentiation, as well as programmed cell death (apoptosis) and tissue remodeling. Abnormalities in embryonic development can lead to birth defects or other developmental disorders.

It's important to note that the term "embryo" is used to describe the developing organism from fertilization until the end of the 8th week of pregnancy in humans, after which it is called a fetus.

Sodium is an essential mineral and electrolyte that is necessary for human health. In a medical context, sodium is often discussed in terms of its concentration in the blood, as measured by serum sodium levels. The normal range for serum sodium is typically between 135 and 145 milliequivalents per liter (mEq/L).

Sodium plays a number of important roles in the body, including:

* Regulating fluid balance: Sodium helps to regulate the amount of water in and around your cells, which is important for maintaining normal blood pressure and preventing dehydration.
* Facilitating nerve impulse transmission: Sodium is involved in the generation and transmission of electrical signals in the nervous system, which is necessary for proper muscle function and coordination.
* Assisting with muscle contraction: Sodium helps to regulate muscle contractions by interacting with other minerals such as calcium and potassium.

Low sodium levels (hyponatremia) can cause symptoms such as confusion, seizures, and coma, while high sodium levels (hypernatremia) can lead to symptoms such as weakness, muscle cramps, and seizures. Both conditions require medical treatment to correct.

The vitelline membrane is a thin, transparent, flexible, and protective membrane that surrounds the yolk in bird, reptile, and some insect eggs. It provides nutrition and physical protection to the developing embryo during incubation. In medical terms, it is not directly relevant as it does not have a counterpart or equivalent structure in mammalian embryology.

Northern blotting is a laboratory technique used in molecular biology to detect and analyze specific RNA molecules (such as mRNA) in a mixture of total RNA extracted from cells or tissues. This technique is called "Northern" blotting because it is analogous to the Southern blotting method, which is used for DNA detection.

The Northern blotting procedure involves several steps:

1. Electrophoresis: The total RNA mixture is first separated based on size by running it through an agarose gel using electrical current. This separates the RNA molecules according to their length, with smaller RNA fragments migrating faster than larger ones.

2. Transfer: After electrophoresis, the RNA bands are denatured (made single-stranded) and transferred from the gel onto a nitrocellulose or nylon membrane using a technique called capillary transfer or vacuum blotting. This step ensures that the order and relative positions of the RNA fragments are preserved on the membrane, similar to how they appear in the gel.

3. Cross-linking: The RNA is then chemically cross-linked to the membrane using UV light or heat treatment, which helps to immobilize the RNA onto the membrane and prevent it from washing off during subsequent steps.

4. Prehybridization: Before adding the labeled probe, the membrane is prehybridized in a solution containing blocking agents (such as salmon sperm DNA or yeast tRNA) to minimize non-specific binding of the probe to the membrane.

5. Hybridization: A labeled nucleic acid probe, specific to the RNA of interest, is added to the prehybridization solution and allowed to hybridize (form base pairs) with its complementary RNA sequence on the membrane. The probe can be either a DNA or an RNA molecule, and it is typically labeled with a radioactive isotope (such as ³²P) or a non-radioactive label (such as digoxigenin).

6. Washing: After hybridization, the membrane is washed to remove unbound probe and reduce background noise. The washing conditions (temperature, salt concentration, and detergent concentration) are optimized based on the stringency required for specific hybridization.

7. Detection: The presence of the labeled probe is then detected using an appropriate method, depending on the type of label used. For radioactive probes, this typically involves exposing the membrane to X-ray film or a phosphorimager screen and analyzing the resulting image. For non-radioactive probes, detection can be performed using colorimetric, chemiluminescent, or fluorescent methods.

8. Data analysis: The intensity of the signal is quantified and compared to controls (such as housekeeping genes) to determine the relative expression level of the RNA of interest. This information can be used for various purposes, such as identifying differentially expressed genes in response to a specific treatment or comparing gene expression levels across different samples or conditions.

Signal transduction is the process by which a cell converts an extracellular signal, such as a hormone or neurotransmitter, into an intracellular response. This involves a series of molecular events that transmit the signal from the cell surface to the interior of the cell, ultimately resulting in changes in gene expression, protein activity, or metabolism.

The process typically begins with the binding of the extracellular signal to a receptor located on the cell membrane. This binding event activates the receptor, which then triggers a cascade of intracellular signaling molecules, such as second messengers, protein kinases, and ion channels. These molecules amplify and propagate the signal, ultimately leading to the activation or inhibition of specific cellular responses.

Signal transduction pathways are highly regulated and can be modulated by various factors, including other signaling molecules, post-translational modifications, and feedback mechanisms. Dysregulation of these pathways has been implicated in a variety of diseases, including cancer, diabetes, and neurological disorders.

A "gene library" is not a recognized term in medical genetics or molecular biology. However, the closest concept that might be referred to by this term is a "genomic library," which is a collection of DNA clones that represent the entire genetic material of an organism. These libraries are used for various research purposes, such as identifying and studying specific genes or gene functions.

T-box domain proteins are a family of transcription factors that share a highly conserved DNA-binding domain, known as the T-box. The T-box domain is a DNA-binding motif that specifically recognizes and binds to T-box binding elements (TBEs) in the regulatory regions of target genes. These proteins play crucial roles during embryonic development, particularly in the formation of specific tissues and organs, such as the heart, limbs, and brain. Mutations in T-box domain proteins can lead to various congenital defects and developmental disorders. Some examples of T-box domain proteins include TBX1, TBX5, and TBX20.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

'Gene expression regulation' refers to the processes that control whether, when, and where a particular gene is expressed, meaning the production of a specific protein or functional RNA encoded by that gene. This complex mechanism can be influenced by various factors such as transcription factors, chromatin remodeling, DNA methylation, non-coding RNAs, and post-transcriptional modifications, among others. Proper regulation of gene expression is crucial for normal cellular function, development, and maintaining homeostasis in living organisms. Dysregulation of gene expression can lead to various diseases, including cancer and genetic disorders.

"Anura" is a term used in the field of zoology, particularly in the study of amphibians. It refers to a order that includes frogs and toads. The name "Anura" comes from the Greek language, with "an-" meaning "without," and "oura" meaning "tail." This is a reference to the fact that members of this order lack tails in their adult form.

The Anura order is characterized by several distinct features:

1. They have short, powerful legs that are well adapted for jumping or leaping.
2. Their forelimbs are smaller and less specialized than their hind limbs.
3. Most anurans have a moist, glandular skin, which helps them to breathe and absorb water.
4. Anura includes both aquatic and terrestrial species, with varying degrees of adaptations for each environment.
5. They lay their eggs in water, and their larvae (tadpoles) are aquatic, undergoing a process called metamorphosis to transform into the adult form.

Anura contains approximately 7,000 known species, making it one of the largest orders of vertebrates. They have a cosmopolitan distribution and can be found on every continent except Antarctica. Anurans play essential roles in many ecosystems as both predators and prey, contributing to the regulation of insect populations and serving as indicators of environmental health.

Nuclear proteins are a category of proteins that are primarily found in the nucleus of a eukaryotic cell. They play crucial roles in various nuclear functions, such as DNA replication, transcription, repair, and RNA processing. This group includes structural proteins like lamins, which form the nuclear lamina, and regulatory proteins, such as histones and transcription factors, that are involved in gene expression. Nuclear localization signals (NLS) often help target these proteins to the nucleus by interacting with importin proteins during active transport across the nuclear membrane.

DNA primers are short single-stranded DNA molecules that serve as a starting point for DNA synthesis. They are typically used in laboratory techniques such as the polymerase chain reaction (PCR) and DNA sequencing. The primer binds to a complementary sequence on the DNA template through base pairing, providing a free 3'-hydroxyl group for the DNA polymerase enzyme to add nucleotides and synthesize a new strand of DNA. This allows for specific and targeted amplification or analysis of a particular region of interest within a larger DNA molecule.

The neural crest is a transient, multipotent embryonic cell population that originates from the ectoderm (outermost layer) of the developing neural tube (precursor to the central nervous system). These cells undergo an epithelial-to-mesenchymal transition and migrate throughout the embryo, giving rise to a diverse array of cell types and structures.

Neural crest cells differentiate into various tissues, including:

1. Peripheral nervous system (PNS) components: sensory neurons, sympathetic and parasympathetic ganglia, and glial cells (e.g., Schwann cells).
2. Facial bones and cartilage, as well as connective tissue of the skull.
3. Melanocytes, which are pigment-producing cells in the skin.
4. Smooth muscle cells in major blood vessels, heart, gastrointestinal tract, and other organs.
5. Secretory cells in endocrine glands (e.g., chromaffin cells of the adrenal medulla).
6. Parts of the eye, such as the cornea and iris stroma.
7. Dental tissues, including dentin, cementum, and dental pulp.

Due to their wide-ranging contributions to various tissues and organs, neural crest cells play a crucial role in embryonic development and organogenesis. Abnormalities in neural crest cell migration or differentiation can lead to several congenital disorders, such as neurocristopathies.

Meiosis is a type of cell division that results in the formation of four daughter cells, each with half the number of chromosomes as the parent cell. It is a key process in sexual reproduction, where it generates gametes or sex cells (sperm and eggs).

The process of meiosis involves one round of DNA replication followed by two successive nuclear divisions, meiosis I and meiosis II. In meiosis I, homologous chromosomes pair, form chiasma and exchange genetic material through crossing over, then separate from each other. In meiosis II, sister chromatids separate, leading to the formation of four haploid cells. This process ensures genetic diversity in offspring by shuffling and recombining genetic information during the formation of gametes.

Antisense oligonucleotides (ASOs) are short synthetic single stranded DNA-like molecules that are designed to complementarily bind to a specific RNA sequence through base-pairing, with the goal of preventing the translation of the target RNA into protein or promoting its degradation.

The antisense oligonucleotides work by hybridizing to the targeted messenger RNA (mRNA) molecule and inducing RNase H-mediated degradation, sterically blocking ribosomal translation, or modulating alternative splicing of the pre-mRNA.

ASOs have shown promise as therapeutic agents for various genetic diseases, viral infections, and cancers by specifically targeting disease-causing genes. However, their clinical application is still facing challenges such as off-target effects, stability, delivery, and potential immunogenicity.

Recombinant fusion proteins are artificially created biomolecules that combine the functional domains or properties of two or more different proteins into a single protein entity. They are generated through recombinant DNA technology, where the genes encoding the desired protein domains are linked together and expressed as a single, chimeric gene in a host organism, such as bacteria, yeast, or mammalian cells.

The resulting fusion protein retains the functional properties of its individual constituent proteins, allowing for novel applications in research, diagnostics, and therapeutics. For instance, recombinant fusion proteins can be designed to enhance protein stability, solubility, or immunogenicity, making them valuable tools for studying protein-protein interactions, developing targeted therapies, or generating vaccines against infectious diseases or cancer.

Examples of recombinant fusion proteins include:

1. Etaglunatide (ABT-523): A soluble Fc fusion protein that combines the heavy chain fragment crystallizable region (Fc) of an immunoglobulin with the extracellular domain of the human interleukin-6 receptor (IL-6R). This fusion protein functions as a decoy receptor, neutralizing IL-6 and its downstream signaling pathways in rheumatoid arthritis.
2. Etanercept (Enbrel): A soluble TNF receptor p75 Fc fusion protein that binds to tumor necrosis factor-alpha (TNF-α) and inhibits its proinflammatory activity, making it a valuable therapeutic option for treating autoimmune diseases like rheumatoid arthritis, ankylosing spondylitis, and psoriasis.
3. Abatacept (Orencia): A fusion protein consisting of the extracellular domain of cytotoxic T-lymphocyte antigen 4 (CTLA-4) linked to the Fc region of an immunoglobulin, which downregulates T-cell activation and proliferation in autoimmune diseases like rheumatoid arthritis.
4. Belimumab (Benlysta): A monoclonal antibody that targets B-lymphocyte stimulator (BLyS) protein, preventing its interaction with the B-cell surface receptor and inhibiting B-cell activation in systemic lupus erythematosus (SLE).
5. Romiplostim (Nplate): A fusion protein consisting of a thrombopoietin receptor agonist peptide linked to an immunoglobulin Fc region, which stimulates platelet production in patients with chronic immune thrombocytopenia (ITP).
6. Darbepoetin alfa (Aranesp): A hyperglycosylated erythropoiesis-stimulating protein that functions as a longer-acting form of recombinant human erythropoietin, used to treat anemia in patients with chronic kidney disease or cancer.
7. Palivizumab (Synagis): A monoclonal antibody directed against the F protein of respiratory syncytial virus (RSV), which prevents RSV infection and is administered prophylactically to high-risk infants during the RSV season.
8. Ranibizumab (Lucentis): A recombinant humanized monoclonal antibody fragment that binds and inhibits vascular endothelial growth factor A (VEGF-A), used in the treatment of age-related macular degeneration, diabetic retinopathy, and other ocular disorders.
9. Cetuximab (Erbitux): A chimeric monoclonal antibody that binds to epidermal growth factor receptor (EGFR), used in the treatment of colorectal cancer and head and neck squamous cell carcinoma.
10. Adalimumab (Humira): A fully humanized monoclonal antibody that targets tumor necrosis factor-alpha (TNF-α), used in the treatment of various inflammatory diseases, including rheumatoid arthritis, psoriasis, and Crohn's disease.
11. Bevacizumab (Avastin): A recombinant humanized monoclonal antibody that binds to VEGF-A, used in the treatment of various cancers, including colorectal, lung, breast, and kidney cancer.
12. Trastuzumab (Herceptin): A humanized monoclonal antibody that targets HER2/neu receptor, used in the treatment of breast cancer.
13. Rituximab (Rituxan): A chimeric monoclonal antibody that binds to CD20 antigen on B cells, used in the treatment of non-Hodgkin's lymphoma and rheumatoid arthritis.
14. Palivizumab (Synagis): A humanized monoclonal antibody that binds to the F protein of respiratory syncytial virus, used in the prevention of respiratory syncytial virus infection in high-risk infants.
15. Infliximab (Remicade): A chimeric monoclonal antibody that targets TNF-α, used in the treatment of various inflammatory diseases, including Crohn's disease, ulcerative colitis, rheumatoid arthritis, and ankylosing spondylitis.
16. Natalizumab (Tysabri): A humanized monoclonal antibody that binds to α4β1 integrin, used in the treatment of multiple sclerosis and Crohn's disease.
17. Adalimumab (Humira): A fully human monoclonal antibody that targets TNF-α, used in the treatment of various inflammatory diseases, including rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, Crohn's disease, and ulcerative colitis.
18. Golimumab (Simponi): A fully human monoclonal antibody that targets TNF-α, used in the treatment of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and ulcerative colitis.
19. Certolizumab pegol (Cimzia): A PEGylated Fab' fragment of a humanized monoclonal antibody that targets TNF-α, used in the treatment of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and Crohn's disease.
20. Ustekinumab (Stelara): A fully human monoclonal antibody that targets IL-12 and IL-23, used in the treatment of psoriasis, psoriatic arthritis, and Crohn's disease.
21. Secukinumab (Cosentyx): A fully human monoclonal antibody that targets IL-17A, used in the treatment of psoriasis, psoriatic arthritis, and ankylosing spondylitis.
22. Ixekizumab (Taltz): A fully human monoclonal antibody that targets IL-17A, used in the treatment of psoriasis and psoriatic arthritis.
23. Brodalumab (Siliq): A fully human monoclonal antibody that targets IL-17 receptor A, used in the treatment of psoriasis.
24. Sarilumab (Kevzara): A fully human monoclonal antibody that targets the IL-6 receptor, used in the treatment of rheumatoid arthritis.
25. Tocilizumab (Actemra): A humanized monoclonal antibody that targets the IL-6 receptor, used in the treatment of rheumatoid arthritis, systemic juvenile idiopathic arthritis, polyarticular juvenile idiopathic arthritis, giant cell arteritis, and chimeric antigen receptor T-cell-induced cytokine release syndrome.
26. Siltuximab (Sylvant): A chimeric monoclonal antibody that targets IL-6, used in the treatment of multicentric Castleman disease.
27. Satralizumab (Enspryng): A humanized monoclonal antibody that targets IL-6 receptor alpha, used in the treatment of neuromyelitis optica spectrum disorder.
28. Sirukumab (Plivensia): A human monoclonal antibody that targets IL-6, used in the treatment

Ion channel gating refers to the process by which ion channels in cell membranes open and close in response to various stimuli, allowing ions such as sodium, potassium, and calcium to flow into or out of the cell. This movement of ions is crucial for many physiological processes, including the generation and transmission of electrical signals in nerve cells, muscle contraction, and the regulation of hormone secretion.

Ion channel gating can be regulated by various factors, including voltage changes across the membrane (voltage-gated channels), ligand binding (ligand-gated channels), mechanical stress (mechanosensitive channels), or other intracellular signals (second messenger-gated channels). The opening and closing of ion channels are highly regulated and coordinated processes that play a critical role in maintaining the proper functioning of cells and organ systems.

Bone Morphogenetic Proteins (BMPs) are a group of growth factors that play crucial roles in the development, growth, and repair of bones and other tissues. They belong to the Transforming Growth Factor-β (TGF-β) superfamily and were first discovered when researchers found that certain proteins extracted from demineralized bone matrix had the ability to induce new bone formation.

BMPs stimulate the differentiation of mesenchymal stem cells into osteoblasts, which are the cells responsible for bone formation. They also promote the recruitment and proliferation of these cells, enhancing the overall process of bone regeneration. In addition to their role in bone biology, BMPs have been implicated in various other biological processes, including embryonic development, wound healing, and the regulation of fat metabolism.

There are several types of BMPs (BMP-2, BMP-4, BMP-7, etc.) that exhibit distinct functions and expression patterns. Due to their ability to stimulate bone formation, recombinant human BMPs have been used in clinical applications, such as spinal fusion surgery and non-healing fracture treatment. However, the use of BMPs in medicine has been associated with certain risks and complications, including uncontrolled bone growth, inflammation, and cancer development, which necessitates further research to optimize their therapeutic potential.

Thyroid hormones are hormones produced and released by the thyroid gland, a small endocrine gland located in the neck that helps regulate metabolism, growth, and development in the human body. The two main thyroid hormones are triiodothyronine (T3) and thyroxine (T4), which contain iodine atoms. These hormones play a crucial role in various bodily functions, including heart rate, body temperature, digestion, and brain development. They help regulate the rate at which your body uses energy, affects how sensitive your body is to other hormones, and plays a vital role in the development and differentiation of all cells of the human body. Thyroid hormone levels are regulated by the hypothalamus and pituitary gland through a feedback mechanism that helps maintain proper balance.

Electron microscopy (EM) is a type of microscopy that uses a beam of electrons to create an image of the sample being examined, resulting in much higher magnification and resolution than light microscopy. There are several types of electron microscopy, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), and reflection electron microscopy (REM).

In TEM, a beam of electrons is transmitted through a thin slice of the sample, and the electrons that pass through the sample are focused to form an image. This technique can provide detailed information about the internal structure of cells, viruses, and other biological specimens, as well as the composition and structure of materials at the atomic level.

In SEM, a beam of electrons is scanned across the surface of the sample, and the electrons that are scattered back from the surface are detected to create an image. This technique can provide information about the topography and composition of surfaces, as well as the structure of materials at the microscopic level.

REM is a variation of SEM in which the beam of electrons is reflected off the surface of the sample, rather than scattered back from it. This technique can provide information about the surface chemistry and composition of materials.

Electron microscopy has a wide range of applications in biology, medicine, and materials science, including the study of cellular structure and function, disease diagnosis, and the development of new materials and technologies.

Endoderm is the innermost of the three primary germ layers in a developing embryo, along with the ectoderm and mesoderm. The endoderm gives rise to several internal tissues and organs, most notably those found in the digestive system and respiratory system. Specifically, it forms the lining of the gut tube, which eventually becomes the epithelial lining of the gastrointestinal tract, liver, pancreas, lungs, and other associated structures.

During embryonic development, the endoderm arises from the inner cell mass of the blastocyst, following a series of cell divisions and migrations that help to establish the basic body plan of the organism. As the embryo grows and develops, the endoderm continues to differentiate into more specialized tissues and structures, playing a critical role in the formation of many essential bodily functions.

A cell membrane, also known as the plasma membrane, is a thin semi-permeable phospholipid bilayer that surrounds all cells in animals, plants, and microorganisms. It functions as a barrier to control the movement of substances in and out of the cell, allowing necessary molecules such as nutrients, oxygen, and signaling molecules to enter while keeping out harmful substances and waste products. The cell membrane is composed mainly of phospholipids, which have hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails. This unique structure allows the membrane to be flexible and fluid, yet selectively permeable. Additionally, various proteins are embedded in the membrane that serve as channels, pumps, receptors, and enzymes, contributing to the cell's overall functionality and communication with its environment.

A cell-free system is a biochemical environment in which biological reactions can occur outside of an intact living cell. These systems are often used to study specific cellular processes or pathways, as they allow researchers to control and manipulate the conditions in which the reactions take place. In a cell-free system, the necessary enzymes, substrates, and cofactors for a particular reaction are provided in a test tube or other container, rather than within a whole cell.

Cell-free systems can be derived from various sources, including bacteria, yeast, and mammalian cells. They can be used to study a wide range of cellular processes, such as transcription, translation, protein folding, and metabolism. For example, a cell-free system might be used to express and purify a specific protein, or to investigate the regulation of a particular metabolic pathway.

One advantage of using cell-free systems is that they can provide valuable insights into the mechanisms of cellular processes without the need for time-consuming and resource-intensive cell culture or genetic manipulation. Additionally, because cell-free systems are not constrained by the limitations of a whole cell, they offer greater flexibility in terms of reaction conditions and the ability to study complex or transient interactions between biological molecules.

Overall, cell-free systems are an important tool in molecular biology and biochemistry, providing researchers with a versatile and powerful means of investigating the fundamental processes that underlie life at the cellular level.

A dose-response relationship in the context of drugs refers to the changes in the effects or symptoms that occur as the dose of a drug is increased or decreased. Generally, as the dose of a drug is increased, the severity or intensity of its effects also increases. Conversely, as the dose is decreased, the effects of the drug become less severe or may disappear altogether.

The dose-response relationship is an important concept in pharmacology and toxicology because it helps to establish the safe and effective dosage range for a drug. By understanding how changes in the dose of a drug affect its therapeutic and adverse effects, healthcare providers can optimize treatment plans for their patients while minimizing the risk of harm.

The dose-response relationship is typically depicted as a curve that shows the relationship between the dose of a drug and its effect. The shape of the curve may vary depending on the drug and the specific effect being measured. Some drugs may have a steep dose-response curve, meaning that small changes in the dose can result in large differences in the effect. Other drugs may have a more gradual dose-response curve, where larger changes in the dose are needed to produce significant effects.

In addition to helping establish safe and effective dosages, the dose-response relationship is also used to evaluate the potential therapeutic benefits and risks of new drugs during clinical trials. By systematically testing different doses of a drug in controlled studies, researchers can identify the optimal dosage range for the drug and assess its safety and efficacy.

Mitosis is a type of cell division in which the genetic material of a single cell, called the mother cell, is equally distributed into two identical daughter cells. It's a fundamental process that occurs in multicellular organisms for growth, maintenance, and repair, as well as in unicellular organisms for reproduction.

The process of mitosis can be broken down into several stages: prophase, prometaphase, metaphase, anaphase, and telophase. During prophase, the chromosomes condense and become visible, and the nuclear envelope breaks down. In prometaphase, the nuclear membrane is completely disassembled, and the mitotic spindle fibers attach to the chromosomes at their centromeres.

During metaphase, the chromosomes align at the metaphase plate, an imaginary line equidistant from the two spindle poles. In anaphase, sister chromatids are pulled apart by the spindle fibers and move toward opposite poles of the cell. Finally, in telophase, new nuclear envelopes form around each set of chromosomes, and the chromosomes decondense and become less visible.

Mitosis is followed by cytokinesis, a process that divides the cytoplasm of the mother cell into two separate daughter cells. The result of mitosis and cytokinesis is two genetically identical cells, each with the same number and kind of chromosomes as the original parent cell.

Albinism is a group of genetic disorders that result in little or no production of melanin, the pigment responsible for coloring skin, hair, and eyes. It is caused by mutations in genes involved in the production of melanin. There are several types of albinism, including oculocutaneous albinism (OCA) and ocular albinism (OA). OCA affects the skin, hair, and eyes, while OA primarily affects the eyes.

People with albinism typically have very pale skin, white or light-colored hair, and light-colored eyes. They may also have vision problems, such as sensitivity to light (photophobia), rapid eye movements (nystagmus), and decreased visual acuity. The severity of these symptoms can vary depending on the type and extent of albinism.

Albinism is inherited in an autosomal recessive manner, which means that an individual must inherit two copies of the mutated gene, one from each parent, in order to have the condition. If both parents are carriers of a mutated gene for albinism, they have a 25% chance with each pregnancy of having a child with albinism.

There is no cure for albinism, but individuals with the condition can take steps to protect their skin and eyes from the sun and use visual aids to help with vision problems. It is important for people with albinism to undergo regular eye examinations and to use sun protection, such as sunscreen, hats, and sunglasses, to prevent skin damage and skin cancer.

Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) is a laboratory technique used in molecular biology to amplify and detect specific DNA sequences. This technique is particularly useful for the detection and quantification of RNA viruses, as well as for the analysis of gene expression.

The process involves two main steps: reverse transcription and polymerase chain reaction (PCR). In the first step, reverse transcriptase enzyme is used to convert RNA into complementary DNA (cDNA) by reading the template provided by the RNA molecule. This cDNA then serves as a template for the PCR amplification step.

In the second step, the PCR reaction uses two primers that flank the target DNA sequence and a thermostable polymerase enzyme to repeatedly copy the targeted cDNA sequence. The reaction mixture is heated and cooled in cycles, allowing the primers to anneal to the template, and the polymerase to extend the new strand. This results in exponential amplification of the target DNA sequence, making it possible to detect even small amounts of RNA or cDNA.

RT-PCR is a sensitive and specific technique that has many applications in medical research and diagnostics, including the detection of viruses such as HIV, hepatitis C virus, and SARS-CoV-2 (the virus that causes COVID-19). It can also be used to study gene expression, identify genetic mutations, and diagnose genetic disorders.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

Bufonidae is a family of toads, characterized by the presence of parotoid glands that produce bufotoxins, a group of toxic secretions. These toads are found worldwide, except for Australia, New Zealand, Madagascar, and some isolated islands. They vary in size, shape, and coloration, depending on the species. Some notable members of this family include the common toad (Bufo bufo) and the Colorado River toad (Incilius alvarius). It is important to note that while these toads have toxic secretions, they are not typically harmful to humans unless ingested or if their secretions come into contact with mucous membranes or broken skin.

Biological models, also known as physiological models or organismal models, are simplified representations of biological systems, processes, or mechanisms that are used to understand and explain the underlying principles and relationships. These models can be theoretical (conceptual or mathematical) or physical (such as anatomical models, cell cultures, or animal models). They are widely used in biomedical research to study various phenomena, including disease pathophysiology, drug action, and therapeutic interventions.

Examples of biological models include:

1. Mathematical models: These use mathematical equations and formulas to describe complex biological systems or processes, such as population dynamics, metabolic pathways, or gene regulation networks. They can help predict the behavior of these systems under different conditions and test hypotheses about their underlying mechanisms.
2. Cell cultures: These are collections of cells grown in a controlled environment, typically in a laboratory dish or flask. They can be used to study cellular processes, such as signal transduction, gene expression, or metabolism, and to test the effects of drugs or other treatments on these processes.
3. Animal models: These are living organisms, usually vertebrates like mice, rats, or non-human primates, that are used to study various aspects of human biology and disease. They can provide valuable insights into the pathophysiology of diseases, the mechanisms of drug action, and the safety and efficacy of new therapies.
4. Anatomical models: These are physical representations of biological structures or systems, such as plastic models of organs or tissues, that can be used for educational purposes or to plan surgical procedures. They can also serve as a basis for developing more sophisticated models, such as computer simulations or 3D-printed replicas.

Overall, biological models play a crucial role in advancing our understanding of biology and medicine, helping to identify new targets for therapeutic intervention, develop novel drugs and treatments, and improve human health.

Membrane proteins are a type of protein that are embedded in the lipid bilayer of biological membranes, such as the plasma membrane of cells or the inner membrane of mitochondria. These proteins play crucial roles in various cellular processes, including:

1. Cell-cell recognition and signaling
2. Transport of molecules across the membrane (selective permeability)
3. Enzymatic reactions at the membrane surface
4. Energy transduction and conversion
5. Mechanosensation and signal transduction

Membrane proteins can be classified into two main categories: integral membrane proteins, which are permanently associated with the lipid bilayer, and peripheral membrane proteins, which are temporarily or loosely attached to the membrane surface. Integral membrane proteins can further be divided into three subcategories based on their topology:

1. Transmembrane proteins, which span the entire width of the lipid bilayer with one or more alpha-helices or beta-barrels.
2. Lipid-anchored proteins, which are covalently attached to lipids in the membrane via a glycosylphosphatidylinositol (GPI) anchor or other lipid modifications.
3. Monotopic proteins, which are partially embedded in the membrane and have one or more domains exposed to either side of the bilayer.

Membrane proteins are essential for maintaining cellular homeostasis and are targets for various therapeutic interventions, including drug development and gene therapy. However, their structural complexity and hydrophobicity make them challenging to study using traditional biochemical methods, requiring specialized techniques such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and single-particle cryo-electron microscopy (cryo-EM).

Calcium is an essential mineral that is vital for various physiological processes in the human body. The medical definition of calcium is as follows:

Calcium (Ca2+) is a crucial cation and the most abundant mineral in the human body, with approximately 99% of it found in bones and teeth. It plays a vital role in maintaining structural integrity, nerve impulse transmission, muscle contraction, hormonal secretion, blood coagulation, and enzyme activation.

Calcium homeostasis is tightly regulated through the interplay of several hormones, including parathyroid hormone (PTH), calcitonin, and vitamin D. Dietary calcium intake, absorption, and excretion are also critical factors in maintaining optimal calcium levels in the body.

Hypocalcemia refers to low serum calcium levels, while hypercalcemia indicates high serum calcium levels. Both conditions can have detrimental effects on various organ systems and require medical intervention to correct.

DNA restriction enzymes, also known as restriction endonucleases, are a type of enzyme that cut double-stranded DNA at specific recognition sites. These enzymes are produced by bacteria and archaea as a defense mechanism against foreign DNA, such as that found in bacteriophages (viruses that infect bacteria).

Restriction enzymes recognize specific sequences of nucleotides (the building blocks of DNA) and cleave the phosphodiester bonds between them. The recognition sites for these enzymes are usually palindromic, meaning that the sequence reads the same in both directions when facing the opposite strands of DNA.

Restriction enzymes are widely used in molecular biology research for various applications such as genetic engineering, genome mapping, and DNA fingerprinting. They allow scientists to cut DNA at specific sites, creating precise fragments that can be manipulated and analyzed. The use of restriction enzymes has been instrumental in the development of recombinant DNA technology and the Human Genome Project.

Small nuclear RNA (snRNA) are a type of RNA molecules that are typically around 100-300 nucleotides in length. They are found within the nucleus of eukaryotic cells and are components of small nuclear ribonucleoproteins (snRNPs), which play important roles in various aspects of RNA processing, including splicing of pre-messenger RNA (pre-mRNA) and regulation of transcription.

There are several classes of snRNAs, each with a distinct function. The most well-studied class is the spliceosomal snRNAs, which include U1, U2, U4, U5, and U6 snRNAs. These snRNAs form complexes with proteins to form small nuclear ribonucleoprotein particles (snRNPs) that recognize specific sequences in pre-mRNA and catalyze the removal of introns during splicing.

Other classes of snRNAs include signal recognition particle (SRP) RNA, which is involved in targeting proteins to the endoplasmic reticulum, and Ro60 RNA, which is associated with autoimmune diseases such as systemic lupus erythematosus.

Overall, small nuclear RNAs are essential components of the cellular machinery that regulates gene expression and protein synthesis in eukaryotic cells.

Wnt proteins are a family of secreted signaling molecules that play crucial roles in the regulation of fundamental biological processes, including cell proliferation, differentiation, migration, and survival. They were first discovered in 1982 through genetic studies in Drosophila melanogaster (fruit flies) and have since been found to be highly conserved across various species, from invertebrates to humans.

Wnt proteins exert their effects by binding to specific receptors on the target cell surface, leading to the activation of several intracellular signaling pathways:

1. Canonical Wnt/β-catenin pathway: In the absence of Wnt ligands, β-catenin is continuously degraded by a destruction complex consisting of Axin, APC (Adenomatous polyposis coli), and GSK3β (Glycogen synthase kinase 3 beta). When Wnt proteins bind to their receptors Frizzled and LRP5/6, the formation of a "signalosome" complex leads to the inhibition of the destruction complex, allowing β-catenin to accumulate in the cytoplasm and translocate into the nucleus. Here, it interacts with TCF/LEF (T-cell factor/lymphoid enhancer-binding factor) transcription factors to regulate the expression of target genes involved in cell proliferation, differentiation, and survival.
2. Non-canonical Wnt pathways: These include the Wnt/Ca^2+^ pathway and the planar cell polarity (PCP) pathway. In the Wnt/Ca^2+^ pathway, Wnt ligands bind to Frizzled receptors and activate heterotrimeric G proteins, leading to an increase in intracellular Ca^2+^ levels and activation of downstream targets such as protein kinase C (PKC) and calcium/calmodulin-dependent protein kinase II (CAMKII). These signaling events ultimately regulate cell movement, adhesion, and gene expression. In the PCP pathway, Wnt ligands bind to Frizzled receptors and coreceptor complexes containing Ror2 or Ryk, leading to activation of small GTPases such as RhoA and Rac1, which control cytoskeletal organization and cell polarity.

Dysregulation of Wnt signaling has been implicated in various human diseases, including cancer, developmental disorders, and degenerative conditions. In cancer, aberrant activation of the canonical Wnt/β-catenin pathway contributes to tumor initiation, progression, and metastasis by promoting cell proliferation, survival, and epithelial-mesenchymal transition (EMT). Inhibitors targeting different components of the Wnt signaling pathway are currently being developed as potential therapeutic strategies for cancer treatment.

Molecular weight, also known as molecular mass, is the mass of a molecule. It is expressed in units of atomic mass units (amu) or daltons (Da). Molecular weight is calculated by adding up the atomic weights of each atom in a molecule. It is a useful property in chemistry and biology, as it can be used to determine the concentration of a substance in a solution, or to calculate the amount of a substance that will react with another in a chemical reaction.

The laryngeal muscles are a group of skeletal muscles located in the larynx, also known as the voice box. These muscles play a crucial role in breathing, swallowing, and producing sounds for speech. They include:

1. Cricothyroid muscle: This muscle helps to tense the vocal cords and adjust their pitch during phonation (voice production). It is the only laryngeal muscle that is not innervated by the recurrent laryngeal nerve. Instead, it is supplied by the external branch of the superior laryngeal nerve.
2. Posterior cricoarytenoid muscle: This muscle is primarily responsible for abducting (opening) the vocal cords during breathing and speaking. It is the only muscle that can abduct the vocal cords.
3. Lateral cricoarytenoid muscle: This muscle adducts (closes) the vocal cords during phonation, swallowing, and coughing.
4. Transverse arytenoid muscle: This muscle also contributes to adduction of the vocal cords, working together with the lateral cricoarytenoid muscle. It also helps to relax and lengthen the vocal cords during quiet breathing.
5. Oblique arytenoid muscle: This muscle is involved in adducting, rotating, and shortening the vocal cords. It works together with the transverse arytenoid muscle to provide fine adjustments for voice production.
6. Thyroarytenoid muscle (Vocalis): This muscle forms the main body of the vocal cord and is responsible for its vibration during phonation. The vocalis portion of the muscle helps control pitch and tension in the vocal cords.

These muscles work together to enable various functions of the larynx, such as breathing, swallowing, and speaking.

Chromatin is the complex of DNA, RNA, and proteins that make up the chromosomes in the nucleus of a cell. It is responsible for packaging the long DNA molecules into a more compact form that fits within the nucleus. Chromatin is made up of repeating units called nucleosomes, which consist of a histone protein octamer wrapped tightly by DNA. The structure of chromatin can be altered through chemical modifications to the histone proteins and DNA, which can influence gene expression and other cellular processes.

Tissue distribution, in the context of pharmacology and toxicology, refers to the way that a drug or xenobiotic (a chemical substance found within an organism that is not naturally produced by or expected to be present within that organism) is distributed throughout the body's tissues after administration. It describes how much of the drug or xenobiotic can be found in various tissues and organs, and is influenced by factors such as blood flow, lipid solubility, protein binding, and the permeability of cell membranes. Understanding tissue distribution is important for predicting the potential effects of a drug or toxin on different parts of the body, and for designing drugs with improved safety and efficacy profiles.

Proto-oncogene proteins c-mos are a type of serine/threonine protein kinase that play crucial roles in cell cycle regulation, particularly during the G2 phase and the transition to mitosis. The c-mos gene is a normal version of an oncogene, which can become cancer-causing when mutated or overexpressed. In its normal form, the c-mos protein is involved in controlling the progression of the cell cycle, meiosis, and also has been implicated in neuronal development and synaptic plasticity. Dysregulation of c-mos proto-oncogene proteins can contribute to tumorigenesis and cancer development.

Matrix metalloproteinase 11 (MMP-11) is a type of enzyme that belongs to the matrix metalloproteinase (MMP) family. MMPs are involved in the breakdown and remodeling of extracellular matrix components, such as collagen, elastin, and proteoglycans.

MMP-11, also known as stromelysin-3, is a secreted enzyme that can degrade several extracellular matrix proteins, including gelatin, collagen types III, IV, and V, and laminin. It plays a role in tissue remodeling processes, such as wound healing, embryonic development, and cancer progression.

MMP-11 has been implicated in various pathological conditions, including rheumatoid arthritis, tumor invasion, and metastasis. Its expression is regulated at the transcriptional level by various growth factors, cytokines, and hormones, and its activity is controlled by endogenous inhibitors called tissue inhibitors of metalloproteinases (TIMPs).

The eye is the organ of sight, primarily responsible for detecting and focusing on visual stimuli. It is a complex structure composed of various parts that work together to enable vision. Here are some of the main components of the eye:

1. Cornea: The clear front part of the eye that refracts light entering the eye and protects the eye from harmful particles and microorganisms.
2. Iris: The colored part of the eye that controls the amount of light reaching the retina by adjusting the size of the pupil.
3. Pupil: The opening in the center of the iris that allows light to enter the eye.
4. Lens: A biconvex structure located behind the iris that further refracts light and focuses it onto the retina.
5. Retina: A layer of light-sensitive cells (rods and cones) at the back of the eye that convert light into electrical signals, which are then transmitted to the brain via the optic nerve.
6. Optic Nerve: The nerve that carries visual information from the retina to the brain.
7. Vitreous: A clear, gel-like substance that fills the space between the lens and the retina, providing structural support to the eye.
8. Conjunctiva: A thin, transparent membrane that covers the front of the eye and the inner surface of the eyelids.
9. Extraocular Muscles: Six muscles that control the movement of the eye, allowing for proper alignment and focus.

The eye is a remarkable organ that allows us to perceive and interact with our surroundings. Various medical specialties, such as ophthalmology and optometry, are dedicated to the diagnosis, treatment, and management of various eye conditions and diseases.

A blastocyst is a stage in the early development of a fertilized egg, or embryo, in mammals. It occurs about 5-6 days after fertilization and consists of an outer layer of cells called trophoblasts, which will eventually form the placenta, and an inner cell mass, which will give rise to the fetus. The blastocyst is characterized by a fluid-filled cavity called the blastocoel. This stage is critical for the implantation of the embryo into the uterine lining.

The neural plate is a structure formed during the embryonic development of vertebrates. It is a thickened plate of ectodermal cells located on the dorsal surface of the developing embryo. The neural plate gives rise to the central nervous system, including the brain and spinal cord.

The process of neural plate formation begins with the specification of ectodermal cells into neural fated cells, a process that is regulated by various signaling molecules. Once specified, these cells undergo morphological changes, resulting in the thickening of the ectoderm to form the neural plate.

The neural plate then undergoes a series of folding movements, leading to the formation of the neural tube, which eventually develops into the brain and spinal cord. The edges of the neural plate, known as the neural folds, come together and fuse, forming a closed tube. Failure of the neural folds to fuse properly can result in neural tube defects, such as spina bifida.

Overall, the neural plate is a critical structure in the development of the nervous system in vertebrates, and its formation and subsequent development are tightly regulated by various genetic and environmental factors.

Fetal proteins are a type of proteins that are produced by the fetus during pregnancy and can be detected in various biological samples, such as amniotic fluid or maternal blood. These proteins can provide valuable information about the health and development of the fetus. One commonly studied fetal protein is human chorionic gonadotropin (hCG), which is produced by the placenta and can be used as a marker for pregnancy and to detect potential complications, such as Down syndrome or spinal cord defects. Other examples of fetal proteins include alpha-fetoprotein (AFP) and human placental lactogen (hPL).

A muscle is a soft tissue in our body that contracts to produce force and motion. It is composed mainly of specialized cells called muscle fibers, which are bound together by connective tissue. There are three types of muscles: skeletal (voluntary), smooth (involuntary), and cardiac. Skeletal muscles attach to bones and help in movement, while smooth muscles are found within the walls of organs and blood vessels, helping with functions like digestion and circulation. Cardiac muscle is the specific type that makes up the heart, allowing it to pump blood throughout the body.

Sodium channels are specialized protein structures that are embedded in the membranes of excitable cells, such as nerve and muscle cells. They play a crucial role in the generation and transmission of electrical signals in these cells. Sodium channels are responsible for the rapid influx of sodium ions into the cell during the initial phase of an action potential, which is the electrical signal that travels along the membrane of a neuron or muscle fiber. This sudden influx of sodium ions causes the membrane potential to rapidly reverse, leading to the depolarization of the cell. After the action potential, the sodium channels close and become inactivated, preventing further entry of sodium ions and helping to restore the resting membrane potential.

Sodium channels are composed of a large alpha subunit and one or two smaller beta subunits. The alpha subunit forms the ion-conducting pore, while the beta subunits play a role in modulating the function and stability of the channel. Mutations in sodium channel genes have been associated with various inherited diseases, including certain forms of epilepsy, cardiac arrhythmias, and muscle disorders.

Electrophoresis, polyacrylamide gel (EPG) is a laboratory technique used to separate and analyze complex mixtures of proteins or nucleic acids (DNA or RNA) based on their size and electrical charge. This technique utilizes a matrix made of cross-linked polyacrylamide, a type of gel, which provides a stable and uniform environment for the separation of molecules.

In this process:

1. The polyacrylamide gel is prepared by mixing acrylamide monomers with a cross-linking agent (bis-acrylamide) and a catalyst (ammonium persulfate) in the presence of a buffer solution.
2. The gel is then poured into a mold and allowed to polymerize, forming a solid matrix with uniform pore sizes that depend on the concentration of acrylamide used. Higher concentrations result in smaller pores, providing better resolution for separating smaller molecules.
3. Once the gel has set, it is placed in an electrophoresis apparatus containing a buffer solution. Samples containing the mixture of proteins or nucleic acids are loaded into wells on the top of the gel.
4. An electric field is applied across the gel, causing the negatively charged molecules to migrate towards the positive electrode (anode) while positively charged molecules move toward the negative electrode (cathode). The rate of migration depends on the size, charge, and shape of the molecules.
5. Smaller molecules move faster through the gel matrix and will migrate farther from the origin compared to larger molecules, resulting in separation based on size. Proteins and nucleic acids can be selectively stained after electrophoresis to visualize the separated bands.

EPG is widely used in various research fields, including molecular biology, genetics, proteomics, and forensic science, for applications such as protein characterization, DNA fragment analysis, cloning, mutation detection, and quality control of nucleic acid or protein samples.

DNA replication is the biological process by which DNA makes an identical copy of itself during cell division. It is a fundamental mechanism that allows genetic information to be passed down from one generation of cells to the next. During DNA replication, each strand of the double helix serves as a template for the synthesis of a new complementary strand. This results in the creation of two identical DNA molecules. The enzymes responsible for DNA replication include helicase, which unwinds the double helix, and polymerase, which adds nucleotides to the growing strands.

Phylogeny is the evolutionary history and relationship among biological entities, such as species or genes, based on their shared characteristics. In other words, it refers to the branching pattern of evolution that shows how various organisms have descended from a common ancestor over time. Phylogenetic analysis involves constructing a tree-like diagram called a phylogenetic tree, which depicts the inferred evolutionary relationships among organisms or genes based on molecular sequence data or other types of characters. This information is crucial for understanding the diversity and distribution of life on Earth, as well as for studying the emergence and spread of diseases.

Organ specificity, in the context of immunology and toxicology, refers to the phenomenon where a substance (such as a drug or toxin) or an immune response primarily affects certain organs or tissues in the body. This can occur due to various reasons such as:

1. The presence of specific targets (like antigens in the case of an immune response or receptors in the case of drugs) that are more abundant in these organs.
2. The unique properties of certain cells or tissues that make them more susceptible to damage.
3. The way a substance is metabolized or cleared from the body, which can concentrate it in specific organs.

For example, in autoimmune diseases, organ specificity describes immune responses that are directed against antigens found only in certain organs, such as the thyroid gland in Hashimoto's disease. Similarly, some toxins or drugs may have a particular affinity for liver cells, leading to liver damage or specific drug interactions.

Chlorides are simple inorganic ions consisting of a single chlorine atom bonded to a single charged hydrogen ion (H+). Chloride is the most abundant anion (negatively charged ion) in the extracellular fluid in the human body. The normal range for chloride concentration in the blood is typically between 96-106 milliequivalents per liter (mEq/L).

Chlorides play a crucial role in maintaining electrical neutrality, acid-base balance, and osmotic pressure in the body. They are also essential for various physiological processes such as nerve impulse transmission, maintenance of membrane potentials, and digestion (as hydrochloric acid in the stomach).

Chloride levels can be affected by several factors, including diet, hydration status, kidney function, and certain medical conditions. Increased or decreased chloride levels can indicate various disorders, such as dehydration, kidney disease, Addison's disease, or diabetes insipidus. Therefore, monitoring chloride levels is essential for assessing a person's overall health and diagnosing potential medical issues.

Ribonucleoproteins (RNPs) are complexes composed of ribonucleic acid (RNA) and proteins. They play crucial roles in various cellular processes, including gene expression, RNA processing, transport, stability, and degradation. Different types of RNPs exist, such as ribosomes, spliceosomes, and signal recognition particles, each having specific functions in the cell.

Ribosomes are large RNP complexes responsible for protein synthesis, where messenger RNA (mRNA) is translated into proteins. They consist of two subunits: a smaller subunit containing ribosomal RNA (rRNA) and proteins that recognize the start codon on mRNA, and a larger subunit with rRNA and proteins that facilitate peptide bond formation during translation.

Spliceosomes are dynamic RNP complexes involved in pre-messenger RNA (pre-mRNA) splicing, where introns (non-coding sequences) are removed, and exons (coding sequences) are joined together to form mature mRNA. Spliceosomes consist of five small nuclear ribonucleoproteins (snRNPs), each containing a specific small nuclear RNA (snRNA) and several proteins, as well as numerous additional proteins.

Other RNP complexes include signal recognition particles (SRPs), which are responsible for targeting secretory and membrane proteins to the endoplasmic reticulum during translation, and telomerase, an enzyme that maintains the length of telomeres (the protective ends of chromosomes) by adding repetitive DNA sequences using its built-in RNA component.

In summary, ribonucleoproteins are essential complexes in the cell that participate in various aspects of RNA metabolism and protein synthesis.

Promoter regions in genetics refer to specific DNA sequences located near the transcription start site of a gene. They serve as binding sites for RNA polymerase and various transcription factors that regulate the initiation of gene transcription. These regulatory elements help control the rate of transcription and, therefore, the level of gene expression. Promoter regions can be composed of different types of sequences, such as the TATA box and CAAT box, and their organization and composition can vary between different genes and species.

Somites are transient, segmentally repeated embryonic structures that form along the anterior-posterior body axis during vertebrate development. They are derived from the paraxial mesoderm and give rise to various tissues, including the sclerotome (which forms the vertebrae and ribs), myotome (which forms the skeletal muscles of the back and limbs), and dermatome (which forms the dermis of the skin).

Each somite is a block-like structure that is arranged in a repeating pattern along the notochord, which is a flexible rod-like structure that provides mechanical support to the developing embryo. The formation of somites is a critical step in the development of the vertebrate body plan, as they help to establish the segmental organization of the musculoskeletal system and contribute to the formation of other important structures such as the dermis and the circulatory system.

The process of somitogenesis, or the formation of somites, is a highly regulated and coordinated event that involves the interaction of various signaling molecules and genetic pathways. Defects in somite formation can lead to a range of developmental abnormalities, including spinal deformities, muscle weakness, and skin defects.

Recombinant DNA is a term used in molecular biology to describe DNA that has been created by combining genetic material from more than one source. This is typically done through the use of laboratory techniques such as molecular cloning, in which fragments of DNA are inserted into vectors (such as plasmids or viruses) and then introduced into a host organism where they can replicate and produce many copies of the recombinant DNA molecule.

Recombinant DNA technology has numerous applications in research, medicine, and industry, including the production of recombinant proteins for use as therapeutics, the creation of genetically modified organisms (GMOs) for agricultural or industrial purposes, and the development of new tools for genetic analysis and manipulation.

It's important to note that while recombinant DNA technology has many potential benefits, it also raises ethical and safety concerns, and its use is subject to regulation and oversight in many countries.

A conserved sequence in the context of molecular biology refers to a pattern of nucleotides (in DNA or RNA) or amino acids (in proteins) that has remained relatively unchanged over evolutionary time. These sequences are often functionally important and are highly conserved across different species, indicating strong selection pressure against changes in these regions.

In the case of protein-coding genes, the corresponding amino acid sequence is deduced from the DNA sequence through the genetic code. Conserved sequences in proteins may indicate structurally or functionally important regions, such as active sites or binding sites, that are critical for the protein's activity. Similarly, conserved non-coding sequences in DNA may represent regulatory elements that control gene expression.

Identifying conserved sequences can be useful for inferring evolutionary relationships between species and for predicting the function of unknown genes or proteins.

Goosecoid protein is not a term that has a specific medical definition. However, it is a biological term related to the field of developmental biology and genetics.

Goosecoid protein is a transcription factor that plays a crucial role in embryonic development, particularly during gastrulation - an early stage of embryogenesis where the three germ layers (ectoderm, mesoderm, and endoderm) are formed. The goosecoid gene encodes this protein, and it is primarily expressed in the Spemann-Mangold organizer, a structure located in the dorsal blastopore lip of amphibian embryos. This organizer region is essential for establishing the body axis and inducing the formation of the central nervous system.

In humans, goosecoid protein homologs have been identified, and they are involved in various developmental processes, including limb development and craniofacial morphogenesis. Dysregulation of goosecoid protein expression or function has been implicated in several congenital disorders and cancer types. However, a direct medical definition focusing on 'Goosecoid Protein' is not available due to its broader biological context.

Potassium channels are membrane proteins that play a crucial role in regulating the electrical excitability of cells, including cardiac, neuronal, and muscle cells. These channels facilitate the selective passage of potassium ions (K+) across the cell membrane, maintaining the resting membrane potential and shaping action potentials. They are composed of four or six subunits that assemble to form a central pore through which potassium ions move down their electrochemical gradient. Potassium channels can be modulated by various factors such as voltage, ligands, mechanical stimuli, or temperature, allowing cells to fine-tune their electrical properties and respond to different physiological demands. Dysfunction of potassium channels has been implicated in several diseases, including cardiac arrhythmias, epilepsy, and neurodegenerative disorders.

Regeneration in a medical context refers to the process of renewal, restoration, and growth that replaces damaged or missing cells, tissues, organs, or even whole limbs in some organisms. This complex biological process involves various cellular and molecular mechanisms, such as cell proliferation, differentiation, and migration, which work together to restore the structural and functional integrity of the affected area.

In human medicine, regeneration has attracted significant interest due to its potential therapeutic applications in treating various conditions, including degenerative diseases, trauma, and congenital disorders. Researchers are actively studying the underlying mechanisms of regeneration in various model organisms to develop novel strategies for promoting tissue repair and regeneration in humans.

Examples of regeneration in human medicine include liver regeneration after partial hepatectomy, where the remaining liver lobes can grow back to their original size within weeks, and skin wound healing, where keratinocytes migrate and proliferate to close the wound and restore the epidermal layer. However, the regenerative capacity of humans is limited compared to some other organisms, such as planarians and axolotls, which can regenerate entire body parts or even their central nervous system.

He was also guided by the advice of Harry Zwarenstein, with whom he was later to co-operate in developing the Xenopus laevis ... On pages 45 and 46 of a review titled 'The introduction of Xenopus laevis into developmental biology: of empire, pregnancy ... Gurdon, J B; Hopwood, N (1 February 2003). "The introduction of Xenopus laevis into developmental biology: of empire, pregnancy ... The Shapiro-Zwarenstein pregnancy test received international recognition and Xenopus laevis frogs were exported all over the ...
The African clawed frog (Xenopus laevis), which Hogben first developed as a model organism, is now one of the most widely used ... He developed the African clawed frog (Xenopus laevis) as a model organism for biological research in his early career, attacked ... Gurdon, J B; Hopwood, N (1 February 2003). "The introduction of Xenopus laevis into developmental biology: of empire, pregnancy ... Xenopus laevis. A bibliography. Compiled by H. Zwarenstein ... N. Sapeika ... H.A. Shapiro. African Bookman: Cape Town. OCLC ...
Xenopus laevis, 2002.) So far, three different transcription variants (TVs) have been described for CK1δ in humans (Homo ... subsequently affected Wnt/β-catenin signal transduction resulted in development of an ectopic dorsal axis in Xenopus laevis ... "Genetic and genomic tools for Xenopus research: The NIH Xenopus initiative". Developmental Dynamics. 225 (4): 384-91. doi: ...
Cordenonsi M, Turco F, D'atri F, Hammar E, Martinucci G, Meggio F, Citi S (September 1999). "Xenopus laevis occludin. ... In Xenopus laevis embryos, maternal cingulin is recruited to apical cell-cell junctions from 2-cells stage. In 2004, a protein ... Fesenko I, Kurth T, Sheth B, Fleming TP, Citi S, Hausen P (August 2000). "Tight junction biogenesis in the early Xenopus embryo ... Citi S, D'Atri F, Parry DA (August 2000). "Human and Xenopus cingulin share a modular organization of the coiled-coil rod ...
... gilli (Cape platanna) Xenopus itombwensis Xenopus kobeli Xenopus laevis (African clawed frog or common platanna) ... Xenopus calcaratus Xenopus clivii (Eritrea clawed frog) Xenopus epitropicalis (Cameroon clawed frog) Xenopus eysoole Xenopus ... Xenopus parafraseri Xenopus petersii (Peters' platanna) Xenopus poweri Xenopus pygmaeus (Bouchia clawed frog) Xenopus ... Xenbase is the Model Organism Database (MOD) for both Xenopus laevis and Xenopus tropicalis. All modes of Xenopus research ( ...
Crayon, John J. "Xenopus laevis". AmphibiaWeb. Archived from the original on October 9, 2014. Retrieved October 8, 2012. Moodie ... Snakes have been observed yawning and gaping when trying to swallow African clawed frogs (Xenopus laevis), which gives the ... "Molecular and cellular characterization of urinary bladder-type aquaporin in Xenopus laevis". General and Comparative ... The 1.7GB draft genome of Xenopus tropicalis was the first to be reported for amphibians in 2010. Compared to some salamanders ...
"Xenopus laevis (African clawed frog)". www.cabi.org. "Bactrocera cucurbitae (melon fly)". www.cabi.org. "Blattella germanica ( ... Xenopus laevis (African clawed frog) - Ascension Island Adoretus sinicus (Chinese rose beetle) Aedes albopictus (tiger mosquito ...
Fischberg, M (1958). "Nuclear Transplantation in Xenopus laevis". Nature. 181 (424): 424. Bibcode:1958Natur.181..424F. doi: ... Mertz, J E (1977). "Purified Dnas Are Transcribed after Microinjection into Xenopus Oocytes". PNAS. 74 (4): 1502-1506. Bibcode: ...
Jacox, Laura A.; Dickinson, Amanda J.; Sive, Hazel (26 March 2014). "Facial Transplants in Xenopus laevis Embryos". Journal of ... Kolm, Peggy J.; Sive, Hazel L. (September 1995). "Efficient Hormone-Inducible Protein Function in Xenopus laevis". ... She used a simple anterior organ, the mucus-secreting cement gland of the frog Xenopus, to define the genetic network required ... In 1993, Sive founded the Cold Spring Harbor Course on Early Development of Xenopus. This course continues to run annually. In ...
Cannatella DC, De Sa RO (1993). "Xenopus laevis as a Model Organism". Society of Systematic Biologists. 42 (4): 476-507. doi: ... John Gurdon (1958) transplanted intact nuclei from somatic cells to produce diploid eggs in the frog, Xenopus (an extension of ... Polyploidy also occurs commonly in amphibians; for example the biomedically important genus Xenopus contains many different ... as in the frog genus Xenopus. Organisms in which a particular chromosome, or chromosome segment, is under- or over-represented ...
... laevis/latest_assembly_versions/GCF_001663975.1_Xenopus_laevis_v2". ftp.ncbi.nih.gov. Retrieved 2020-11-30. "Xenopus laevis (ID ... "Xenopus tropicalis (ID 80) - Genome - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2020-12-01. "Index of /genomes/refseq/vertebrate_ ... "Index of /genomes/refseq/vertebrate_other/Xenopus_tropicalis/latest_assembly_versions/GCF_000004195.4_UCB_Xtro_10.0". ftp.ncbi. ...
Nieuwkoop PD, Faber J (1967). Normal table of Xenopus laevis (Daudin). North-Holland, Amsterdam.{{cite book}}: CS1 maint: ... Thale cress (Arabidopsis thaliana) Frog: Xenopus (X. laevis and X. tropicalis). Good embryo supply. Especially suitable for ... Examples that have been especially well studied include tail loss and other changes in the tadpole of the frog Xenopus, and the ... location missing publisher (link) Harland RM, Grainger RM (December 2011). "Xenopus research: metamorphosed by genetics and ...
Baggs JE, Green CB (2003). "Nocturnin, a Deadenylase in Xenopus laevis Retina". Current Biology. 13 (3): 189-198. doi:10.1016/ ...
Speedy homolog E1 (Xenopus laevis) is a protein that in humans is encoded by the SPDYE1 gene. This gene is located at ... "Entrez Gene: Speedy homolog E1 (Xenopus laevis)". Dinarina A, Perez LH, Davila A, Schwab M, Hunt T, Nebreda AR (March 2005). " ...
Xenopus laevis)". Schneider VA, Mercola M (1999). "Spatially distinct head and heart inducers within the Xenopus organizer ... Schneider VA, Mercola M (February 2001). "Wnt antagonism initiates cardiogenesis in Xenopus laevis". Genes & Development. 15 (3 ...
Schneider VA, Mercola M (February 2001). "Wnt antagonism initiates cardiogenesis in Xenopus laevis". Genes & Development. 15 (3 ... They can be found in mice, humans, Xenopus, zebrafish, Drosophila and many others. Wnt signaling begins when a Wnt protein ...
Family: Pipidae Xenopus laevis (LC) Order: Anura. Family: Ranidae Rana aurora (LC) Rana berlandieri (LC) Rana boylii (NT) Rana ...
Xenopus laevis stomach proteins xP1 and xP4; xenopus integumentary mucins A.1 (preprospasmolysin) and C.1, proteins which may ... be involved in defense against microbial infections by protecting the epithelia from the external environment; xenopus skin ...
"Entrez Gene: CLSPN claspin homolog (Xenopus laevis)". Lin SY, Li K, Stewart GS, Elledge SJ (2004). "Human Claspin works with ... Xenopus claspin is an essential upstream regulator of checkpoint kinase 1 and triggers a checkpoint arrest of the cell cycle in ... The human gene appears to be the homolog Xenopus claspin and its function has not been determined. CLSPN has been shown to ... a novel protein required for the activation of Chk1 during a DNA replication checkpoint response in Xenopus egg extracts". Mol ...
"Entrez Gene: DKK3 dickkopf homolog 3 (Xenopus laevis)". Maruyama K, Sugano S (January 1994). "Oligo-capping: a simple method to ...
Kang, Lydia; Marin, Melanie; Kelly, Darcy (1995). "Androgen Biosynthesis and Secretion in Developing Xenopus laevis". General ...
Schwager, J.; Hadji-Azlmi, I. (1984). "Mitogen-induced B-cell differentiation in Xenopus laevis". Differentiation. 27 (3): 182- ... By way of comparison, the structure of IgM from frogs (Xenopus) is predominantly hexameric, IgM from bony fish is predominantly ...
"Entrez Gene: JUB jub, ajuba homolog (Xenopus laevis)". Benzinger A, Muster N, Koch HB, Yates JR, Hermeking H (Jun 2005). " ... and Promotes Meiotic Maturation of Xenopus Oocytes in a Grb2- and Ras-Dependent Manner". Mol Cell Biol. 19 (6): 4379-89. doi: ...
"Entrez Gene: RSPO1 R-spondin homolog (Xenopus laevis)". Chassot, A. -A.; Bradford, S. T.; Auguste, A.; Gregoire, E. P.; ...
In Xenopus laevis, an amphibia, both class receptors are present, unlike fish or mammals. Their class I receptors are expressed ... Freitag, J., Krieger, J., Strotmann, J., & Breer, H. (1995). "Two classes of olfactory receptors in Xenopus laevis". Neuron, 15 ... "Characteristic features and ligand specificity of the two olfactory receptor classes from Xenopus laevis". The Journal of ... "Expression of olfactory receptors during development in Xenopus laevis". The Journal of Experimental Biology, 202 (4), 365-376 ...
Genes for Xenopus laevis U3 small nuclear RNA. Nucleic Acids Res. 1992;20:5435-5442. Marmier-Gourrier N, Cle´ry A, Schlotter F ... Xenopus U3 snoRNA docks on pre-rRNA through a novel base-pairing interaction. submitted. 2003 Herrera A, Olson MOJ. Association ... To form mature rRNA 18S, 5.8S, and 28S, pre-rRNA 40S (Xenopus) and 45S (mammals) must go through a series of cleavages to ... These two stems are also found in pre-rRNA from archaebacteria, however they do not exist in Xenopus pre-rRNA. It is thought ...
Cardew, Gail (1994). Studies on Suc1 in Xenopus laevis (PhD thesis). University of Sussex. OCLC 557309581. EThOS uk.bl.ethos. ... the African clawed frog Xenopus laevis) in 1994. During her doctorate she particularly enjoyed meeting visiting guest speakers ...
Family: Pipidae Xenopus laevis (Daudin, 1802) Order: Anura. Family: Ranidae Glandirana rugosa (Temminck & Schlegel, 1838) ...
"Xenbase - A Xenopus laevis and Xenopus tropicalis resource". "ZFIN Zebrafish Nomenclature". Iverson C, Christiansen S, Glass RM ...
"Entrez Gene: DKK2 dickkopf homolog 2 (Xenopus laevis)". Song Y, Boncompagni AC, Kim SS, Gochnauer HR, Zhang Y, Loots GG, et al ...
annexin II [Xenopus laevis] annexin II [Xenopus laevis]. gi,214531,gb,AAA49885.1, ... Primary structure and expression of the Xenopus laevis gene encoding annexin II.. Gerke V, Koch W, Thiel C. Gene. 1991 Aug 15; ... Primary structure and expression of the Xenopus laevis gene encoding annexin II. [Gene. 1991] ...
Xenopus laevis. (African Clawed Frog). Amphibians-Frogs. Exotic. Collection Info. Point Map. Species Profile. Animated Map. ...
Xenopus laevis/gilli. Taxonomy ID: 8359 (for references in articles please use NCBI:txid8359). current name. Xenopus laevis/ ...
View AmphibiaWeb record for Xenopus laevis*View all photos in CalPhotos of Xenopus laevis *Check Google Images for Xenopus ... Xenopus laevis. Common Platanna Photographer: Simon Tonge. ID: 0000 0000 0114 0447 (2014-01-06). Copyright © 2014 Simon J. ... The photographers identification Xenopus laevis has not been reviewed. Click here to review or comment on the identification. ...
Manipulating the Early Embryo of Xenopus laevis: A Video Guide. Edited By Robert M. Grainger, University of Virginia, ... Early Development of Xenopus laevis: A Laboratory Manual. By Hazel L. Sive, Whitehead Institute for Biomedical Research; Robert ... Xenopus: A Laboratory Manual. Edited By Hazel L. Sive, Northeastern University © 2023 1,067 pages, illustrated (142 color and ...
Manipulating the Early Embryo of Xenopus laevis: A Video Guide. Edited By Robert M. Grainger, University of Virginia, ... Early Development of Xenopus laevis: A Laboratory Manual. By Hazel L. Sive, Whitehead Institute for Biomedical Research; Robert ... Xenopus: A Laboratory Manual. Edited By Hazel L. Sive, Northeastern University © 2023 1,067 pages, illustrated (142 color and ...
Manipulating the Early Embryo of Xenopus laevis: A Video Guide. Edited By Robert M. Grainger, University of Virginia, ... Early Development of Xenopus laevis: A Laboratory Manual. By Hazel L. Sive, Whitehead Institute for Biomedical Research; Robert ... Xenopus: A Laboratory Manual. Edited By Hazel L. Sive, Northeastern University © 2023 1,067 pages, illustrated (142 color and ...
Multiple branching of actin filaments in lamellipodia of Xenopus keratocytes. This image show an enlargement of a local region ... Tatyana M. Svitkina, Gary G. Borisy (2011) CIL:34885, Xenopus laevis, keratocyte. CIL. Dataset. https://doi.org/doi:10.7295/ ... Multiple branching of actin filaments in lamellipodia of Xenopus keratocytes. This image show an enlargement of a local region ...
Species: Xenopus laevis Description: EXRC Clone Number 832. Xenopus laevis Snail homolog 2. To generate probe for in situ. ...
Dissection Culture Analysis Xenopus Laevis Embryonic Retinal Tissue Neural Plate Vertebrate Retina Clinical Research Basic ... Dissection, Culture, and Analysis of Xenopus laevis Embryonic Retinal Tissue. Article DOI: 10.3791/4377-v • 10:22 min • ... Xenopus laevis provides an ideal model system for studying cell fate specification and physiological function of individual ... Journal / Neuroscience / Dissection, Culture, and Analysis of Xenopus laevis Embryonic Retinal Tissue… ...
Presumptive mesoderm cells from Xenopus laevis gastrulae attach to and migrate on substrata coated with fibronectin or laminin ... Xenopus laevis eggs were obtained from matings artificially induced by injecting human chorionic gonadotropin into males and ... The cellular basis of epiboly: An SEM study of deep-cell rearrangement during gastrulation in Xenopus laevis. J. Embryol. exp. ... The presumptive mesoderm cells from Xenopus laevis gastrulae showed rapid adhesion and active movement on the fibronectin- or ...
N2 - Xenopus laevis is an important reference model organism used in many vertebrate studies. Gene mapping in X. laevis, in ... AB - Xenopus laevis is an important reference model organism used in many vertebrate studies. Gene mapping in X. laevis, in ... Xenopus laevis is an important reference model organism used in many vertebrate studies. Gene mapping in X. laevis, in ... abstract = "Xenopus laevis is an important reference model organism used in many vertebrate studies. Gene mapping in X. laevis ...
The effects of heat shock on the morphology and protein synthesis of the epidermis of Xenopus laevis larvae. R W Nickells, R W ... Xenopus laevis larvae. The primary effects of heat shock are the apical swelling of the epidermal cells, giving the epidermis a ... The effects of heat shock on the morphology and protein synthesis of the epidermis of Xenopus laevis larvae.. J Cell Biol 1 ...
... from Xenopus laevis . Plus protein sequence and external database links. ... Domain assignment for gi,33416620,gb,AAH55957, from Xenopus laevis Domain architecture ...
... and phd3 expression in embryos as well as adult tissues of Xenopus laevis. All three phds are maternally provided during ... The spatial expression patterns of phds genes in Xenopus embryos appear to define a distinct synexpression group. Frog phd2 and ... 1. Cloning and characterization of Xenopus laevis drg2, a member of the developmentally regulated GTP-binding protein subfamily ... 3. Molecular cloning and developmental expression of the caveolin gene family in the amphibian Xenopus laevis. ...
Xenopus laevis. en. dc.title. The role of metabotropic glutamate receptors in the control of swimming in hatchling Xenopus ... The role of metabotropic glutamate receptors in the control of swimming in hatchling Xenopus laevis tadpoles. Item metadata. dc ...
Species: Xenopus laevis Description: EXRC Clone Number 851. Xenopus laevis matrix metallopeptidase 9 (gelatinase B, 92kDa ... External Dbs: Unigene laevis cDNA library, Xenopus IMAGE cDNA Library. Description: Cloned unidirectionally. Primer: Oligo dT. ...
Heterologous Expression in Xenopus laevis Oocytes. cRNA (GluK2 4 ng, SGK1 6 ng, NDRG2 6 ng) was injected into stage V-VI ... 2007). (NDRG2) stimulates amiloride-sensitive Na+ currents in Xenopus laevis oocytes and fisher rat thyroid cells. J. Biol. ... For this purpose, the channel was heterologously expressed in Xenopus laevis oocytes, with or without SGK1 and/or NDRG2. ... As shown by electrophysiological techniques and immunohistochemical studies on Xenopus laevis oocytes and hippocampal neurons ...
Two types of exogenous K channel were identified in Xenopus laevis oocytes injected with poly(A+) mRNA from the insulin- ... Expression of K channels in Xenopus laevis oocytes injected with poly(A+) mRNA from the insulin-secreting beta-cell line, HIT ... Expression of K channels in Xenopus laevis oocytes injected with poly(A+) mRNA from the insulin-secreting beta-cell line, HIT ... Two types of exogenous K channel were identified in Xenopus laevis oocytes injected with poly(A+) mRNA from the insulin- ...
Two closely related forms of the single-stranded DNA binding protein purified from Xenopus laevis oocytes mitochondria have ... Amino acid sequence Mitochondria Sequence homology single-stranded DNA-binding protein (Xenopus laevis Escherichia co/i) Amino ... The amino-terminal sequence of the Xenopus laevis mitochondrial SSB is homologous to that of the Escherichia coli protein. FEBS ... The amino-terminal sequence of the Xenopus laevis mitochondrial SSB is homologous to that of the Escherichia coli protein. ...
Melanophore Differentiation in the Periodic Albino Mutant of Xenopus laevis」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。 ... 1987). Melanophore Differentiation in the Periodic Albino Mutant of Xenopus laevis. Pigment Cell Research, 1(3), 197-201. https ... Melanophore Differentiation in the Periodic Albino Mutant of Xenopus laevis. / FUKUZAWA, TOSHIHIKO; IDE, HIROYUKI. In: Pigment ... Melanophore Differentiation in the Periodic Albino Mutant of Xenopus laevis.
NEURAL DEVELOPMENT OF PRIMARY OLFACTORY PATHWAY IN XENOPUS LAEVIS. *Burd, Gail D (PI) ...
We performed time course analyses of initiation of Xenopus laevis rDNA replication in Xenopus egg extracts by two-dimensional ( ... We performed time course analyses of initiation of Xenopus laevis rDNA replication in Xenopus egg extracts by two-dimensional ( ... We performed time course analyses of initiation of Xenopus laevis rDNA replication in Xenopus egg extracts by two-dimensional ( ... We performed time course analyses of initiation of Xenopus laevis rDNA replication in Xenopus egg extracts by two-dimensional ( ...
Our findings highlight the potential to use the optic tectum of Xenopus laevis as an accessible system for the study of the ... The transparent and experimentally accessible optic tectum of Xenopus laevis is an excellent model system for the study of the ... Our findings highlight the potential to use the optic tectum of Xenopus laevis as an accessible system for the study of the ... The transparent and experimentally accessible optic tectum of Xenopus laevis is an excellent model system for the study of the ...
... CAROTENUTO, ROSA;T. C. Petrucci;I ... Immunoprecipitation experiments indicate that at least two isoforms of protein 4.1R are present in Xenopus laevis oocytes: a 56 ... Immunoprecipitation experiments indicate that at least two isoforms of protein 4.1R are present in Xenopus laevis oocytes: a 56 ... Protein 4.1 and its interaction with other cytoskeletal proteins in Xenopus laevis oogenesis / Carotenuto, Rosa; T. C., ...
Kawamura, S, Yoshigai, E, Kuhara, S & Tashiro, K 2008, smyd1 and smyd2 are expressed in muscle tissue in Xenopus laevis, ... Kawamura, S., Yoshigai, E., Kuhara, S., & Tashiro, K. (2008). smyd1 and smyd2 are expressed in muscle tissue in Xenopus laevis ... smyd1 and smyd2 are expressed in muscle tissue in Xenopus laevis. Shinobu Kawamura, Emi Yoshigai, Satoru Kuhara, Kosuke Tashiro ... smyd1 and smyd2 are expressed in muscle tissue in Xenopus laevis. / Kawamura, Shinobu; Yoshigai, Emi; Kuhara, Satoru et al. In ...
He was also guided by the advice of Harry Zwarenstein, with whom he was later to co-operate in developing the Xenopus laevis ... On pages 45 and 46 of a review titled The introduction of Xenopus laevis into developmental biology: of empire, pregnancy ... Gurdon, J B; Hopwood, N (1 February 2003). "The introduction of Xenopus laevis into developmental biology: of empire, pregnancy ... The Shapiro-Zwarenstein pregnancy test received international recognition and Xenopus laevis frogs were exported all over the ...
We established the transgenic Xenopus laevis strain tom3 that expresses ubiquitously red fluorescence from the tdTomato gene ... Their use in transgenic Xenopus tadpoles is especially of interest, because large numbers of living animals can easily be ... We have established a useful new tool to label grafts in Xenopus transplantation experiments. ... Transgenic Xenopus laevis strain expressing ubiquitous red fluorescence. F1 animals of the tom3 strain at the neurula (A), ...
Anuran Xenopus laevis has been used as a model to study regeneration as many tadpole organs can regenerate. In particular, the ... Interestingly, between stage 45 when feeding begins to stage 47, the Xenopus laevis tail cannot regenerate after amputation. ... Here we compared tail regeneration between Xenopus laevis and the highly related diploid anuran Xenopus tropicalis and found ... Evolutionary divergence in tail regeneration between Xenopus laevis and Xenopus tropicalis. *Shouhong Wang1 & ...
  • Here, we report that GABAρ1 receptors, expressed in X. laevis oocytes, were negatively modulated by dopamine and serotonin and less so by octopamine and tyramine. (utmb.edu)
  • Influenza D virus M2 protein exhibits ion channel activity in Xenopus laevis oocytes. (cdc.gov)
  • In contrast, the present experiments, involving the culture of isolated regions of Xenopus embryos, have demonstrated that both mutant and wild‐type melanoblasts differentiate independently of a ventral trunk factor. (elsevierpure.com)
  • Injection into embryos of mRNAs encoding Xenopus banded-hedgehog (X-bhh) or the amino-terminal domain (N) demonstrates that the direct inductive activities of X-bhh are encoded by N. In addition, both N and X-bhh pattern neural tissue by elevating expression of anterior neural genes. (elsevierpure.com)
  • Among them, the anuran amphibian Xenopus (X.) laevis has been a powerful model for studying regeneration. (biomedcentral.com)
  • The effects of heat shock on the morphology and protein synthesis of the epidermis of Xenopus laevis larvae. (rupress.org)
  • DCAF2/Cdt2, which is related to S. pombe Cdt2, functions in Xenopus egg extracts and human cells to destroy the replication licensing protein Cdt1 in S phase and after DNA damage. (nih.gov)
  • We performed time course analyses of initiation of Xenopus laevis rDNA replication in Xenopus egg extracts by two-dimensional (2D) agarose gel electrophoresis. (ewha.ac.kr)
  • That embryonic ventral truck tissue might play a role in expression of the periodic albino mutant phenotype (a p /a p ) in Xenopus laevis was suggested from the experiments of MacMillan (1980). (elsevierpure.com)
  • Experiments were performed in Xenopus laevis , whose full complement of retinal cells is formed in 2 days. (silverchair.com)
  • Note: this is a Xenopus Gene Collection library. (xenbase.org)
  • Recent advancements in genome annotation and gene editing technologies have made the diploid anuran X. tropicalis a superior model than the pseudo-tetraploid X. laevis for genome-wide and genetic studies. (biomedcentral.com)
  • The patterns of embryonic expression and the activities of Xenopus members of the hedgehog gene family are suggestive of roles in neural induction and patterning. (elsevierpure.com)
  • As shown in Fig. 1 , X. laevis tadpoles at stage 46, as expected, failed to generate any of the amputated tail even 7 days after amputation, while nearly complete regeneration of the tail was observed by 5-6 days after of amputation for X. tropicalis tadpoles at stage 46. (biomedcentral.com)
  • Yeo, CY 2004, ' Xenopus laevis rDNA replication initiates in the intergenic spacer ', Korean Journal of Genetics , vol. 26, no. 4, pp. 437-443. (ewha.ac.kr)
  • In Xenopus, Cdt2 is recruited to replication forks via Cdt1 and PCNA, where Cdt1 ubiquitylation occurs. (nih.gov)
  • Introduction to Xenopus laevis as a molecular and histological model for genetic studies. (hal.science)
  • In contrast to previous studies addressing the alteration of molecular biomarkers in the same experimental setup, histological analyses of gonads were very sensitive and indicated an adverse effect of water from Lambro River on reproductive physiology of X. laevis. (unige.it)
  • The use of live South African female Xenopus frogs was common in Europe, the US and Australia from the 1930s and through the 1940s, 1950s and 1960s for testing human pregnancy. (wikipedia.org)
  • In this study, male and female adult South African clawed toads (Xenopus laevis) were exposed to ethinylestradiol (EE2), tamoxifen (TAM), methyldihydrotestosterone (MDHT) and flutamide (FLU) as (anti)estrogenic and (anti)androgenic model compounds, respectively, at a concentration of 10(-8) M, and to water from the river Lambro (LAM), a contaminated watercourse from Northern Italy. (unige.it)
  • This early pregnancy test had been developed by Shapiro and Zwarenstein and it worked by injecting the urine from a human female into the Xenopus laevis frog - the frog would ovulate if the urine had come from a pregnant woman. (wikipedia.org)
  • Xenopus laevis provides an ideal model system for studying cell fate specification and physiological function of individual retinal cells in primary cell culture. (jove.com)
  • FUKUZAWA, TOSHIHIKO & IDE, HIROYUKI 1987, ' Melanophore Differentiation in the Periodic Albino Mutant of Xenopus laevis ', Pigment Cell Research , vol. 1, no. 3, pp. 197-201. (elsevierpure.com)
  • Xenopus laevis matrix metallopeptidase 9 (gelatinase B, 92kDa gelatinase, 92kDa type IV collagenase) (mmp9). (xenbase.org)
  • Interestingly, between stage 45 when feeding begins to stage 47, the Xenopus laevis tail cannot regenerate after amputation. (biomedcentral.com)
  • In a report to the Royal Society of South Africa in October 1933, Shapiro and Zwarenstein announced that in the previous month they had successfully used Xenopus in 35 pregnancy tests. (wikipedia.org)
  • Anuran Xenopus laevis has been used as a model to study regeneration as many tadpole organs can regenerate. (biomedcentral.com)
  • Xenbase: The Xenopus Model Organism Knowledgebase. (xenbase.org)
  • By studying simple hatchling Xenopus laevis tadpoles, we have already identified a population of electrically coupled hindbrain neurons (dINs) that drive swimming. (jneurosci.org)
  • In hatchling Xenopus tadpoles, we have recently established that one type of reticulospinal neuron (dINs) provides the excitatory synaptic drive to spinal neurons during swimming locomotion. (jneurosci.org)
  • Dioxin Exposure Alters Molecular and Morphological Responses to Thyroid Hormone in Xenopus laevis Cultured Cells and Prometamorphic Tadpoles. (nih.gov)
  • We used prometamorphic tadpoles and a cell line of the African clawed frog (Xenopus laevis) to examine immediate effects of dioxin exposure on TH. (nih.gov)
  • National Xenopus Resource at Woods Hole - The National Xenopus Resource serves as a national stock center for X. laevis and X. tropicalis as well as a training center for advanced technologies (e.g. husbandry, cell biology, imaging, genetics, transgenesis, genomics). (rochester.edu)
  • Researchers published a draft genome of the western clawed frog Xenopus tropicalis -the first amphibian genome to be sequenced. (nih.gov)
  • Scientists chose X. tropicalis for initial sequencing over the related African clawed frog Xenopus laevis , which has been used extensively in scientific laboratories. (nih.gov)
  • X. tropicalis is an ideal substitute because it has only 2 copies of each chromosome, matures in only 4 months, and requires less space to house than the larger X. laevis . (nih.gov)
  • PRINS was found to be useful in the localization of repetitive DNA sequences in the X. laevis genome. (illinois.edu)
  • Protocols for transgenesis at a safe harbor site in the Xenopus laevis genome using CRISPR-Cas9. (bvsalud.org)
  • When you look at segments of the Xenopus genome, you literally are looking at structures that are 360 million years old and were part of the genome of the last common ancestor of all birds, frogs, dinosaurs and mammals that ever roamed the earth," explains first author Dr. Uffe Hellsten of the DOE's Joint Genome Institute. (nih.gov)
  • A calibrated volume was microaspirated from the animal-ventral cell in a live 8-cell embryo of Xenopus laevis , and cationic and anionic metabolites were one-pot microextracted from the aspirate, followed by CE-ESI-MS analysis of the same extract. (rsc.org)
  • Gene mapping in X. laevis, in comparison to other reference organisms, is in its early stages. (illinois.edu)
  • 15. Characterization of Xenopus laevis proenkephalin gene. (nih.gov)
  • Chlamydial infection was suspected when widespread pyogranulomatous inflammation and large basophilic intracytoplasmic inclusion bodies were evident histopathologically in African clawed frogs (Xenopus laevis) dying of a spontaneous disease of high morbidity and mortality. (nih.gov)
  • Isolation of Chlamydia psittaci from naturally infected African clawed frogs (Xenopus laevis). (nih.gov)
  • We have established a new transgenesis protocol based on CRISPR -Cas9, "New and Easy XenopusTransgenesis (NEXTrans)," and identified a novel safe harbor site in African clawed frogs, Xenopus laevis . (bvsalud.org)
  • Elk preparaat, met zijn eigen specifieke voordelen, draagt bij aan de experimentele werkwillig van de Xenopus tadpole als een model om te studeren van neurale functie. (jove.com)
  • Wnt mediated beta-catenin activation is understood to be modulated by secreted Frizzled-related proteins, such as XsFRP5 , which is dynamically expressed in the prospective liver / ventral pancreatic precursor cells during late neurula stages, becoming liver specific at tailbud stages and shifting to the posterior stomach /anterior duodenum territory during tadpole stages of Xenopus embryogenesis. (xenbase.org)
  • Few studies have been conducted to localize DNA sequences on X. laevis chromosomes. (illinois.edu)
  • In the present study, PRINS was first used to label the location of telomeres at the ends of in vitro X. laevis chromosomes. (illinois.edu)
  • Freeman, JL & Rayburn, AL 2005, ' Localization of repetitive DNA sequences on in vitro Xenopus laevis chromosomes by primed in situ labeling (PRINS) ', Journal of Heredity , vol. 96, no. 5, pp. 603-606. (illinois.edu)
  • Once the PRINS technique was optimized, this technique was used to determine the chromosomal location of the satellite I repetitive sequence, which is an important sequence in X. laevis development. (illinois.edu)
  • Xenopus laevis is an important reference model organism used in many vertebrate studies. (illinois.edu)
  • Having a complete catalog of the genes in Xenopus , along with those of humans, rats, mice and chickens, will help us reassemble the full complement of ancestral vertebrate genes. (nih.gov)
  • To gain a more detailed view of microtubules in action, researchers designed an experimental system that utilizes an extract of cells from the African clawed frog ( Xenopus laevis ). (nih.gov)
  • Xenopus laevis , or the African clawed frog. (nih.gov)
  • Cannatella,D.C. and de Sa,R. 'Xenopus laevis as a model organism. (nih.gov)
  • For all model organisms we used a disambiguation protocol to identify R01 applicants who attended specific model organism meetings (except for Xenopus because of small numbers). (nih.gov)
  • for Drosophila, C. elegans, and Xenopus, model organism award rates were substantially higher than overall R01 award rates. (nih.gov)
  • Environmental estrogens alter early development in Xenopus laevis. (nih.gov)
  • Initially, Kaisos roles in both general transcription repression and in regulation of canonical and non-canonical Wnt-signaling were thought to contribute to this phenotype, but subsequent studies determined that Kaisos main role in early Xenopus development is restricted to the maintenence of transcriptional silencing. (atlasgeneticsoncology.org)
  • He received his Ph.D. in Dr. Ben Szaro's lab at the State University of New York, focusing on the role of an RNA binding protein in axon development and regeneration in Xenopus Laevis. (nih.gov)
  • Studies of X. laevis have helped answer basic questions about body development, including how organs form and how cell fates are decided. (nih.gov)
  • This image highlights a healthy patch of motile cilia (yellow) on embryonic skin cells (red) of Xenopus laevis . (nih.gov)
  • Dive into the research topics of 'Analysis of histones in xenopus Laevis II. (wustl.edu)
  • Finally Figure 6 shows data for Xenopus research. (nih.gov)
  • and 1,101 Xenopus applications. (nih.gov)
  • European Xenopus Resource Centre, University of Portsmouth, UK - The European Xenopus Resource Centre (EXRC) is funded by the Wellcome Trust, BBSRC and NC3Rs to support researchers using Xenopus models. (rochester.edu)
  • However, X. laevis poses difficulties for genetic studies. (nih.gov)
  • The Gatlin lab is continuing to use their X. laevis system to ask fundamental questions about microtubule assembly. (nih.gov)