Cleavage stage ovum. Medical search

The earliest developmental stage of a fertilized ovum (ZYGOTE) during which there are several mitotic divisions within the ZONA PELLUCIDA. Each cleavage or segmentation yields two BLASTOMERES of about half size of the parent cell. This cleavage stage generally covers the period up to 16-cell MORULA.

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.

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.

A mature haploid female germ cell extruded from the OVARY at OVULATION.

The technique of maintaining or growing mammalian EMBRYOS in vitro. This method offers an opportunity to observe EMBRYONIC DEVELOPMENT; METABOLISM; and susceptibility to TERATOGENS.

The transfer of mammalian embryos from an in vivo or in vitro environment to a suitable host to improve pregnancy or gestational outcome in human or animal. In human fertility treatment programs, preimplantation embryos ranging from the 4-cell stage to the blastocyst stage are transferred to the uterine cavity between 3-5 days after FERTILIZATION IN VITRO.

Morphological and physiological development of EMBRYOS.

The transformation of a liquid to a glassy solid i.e., without the formation of crystals during the cooling process.

The fertilized OVUM resulting from the fusion of a male and a female gamete.

Determination of the nature of a pathological condition or disease in the OVUM; ZYGOTE; or BLASTOCYST prior to implantation. CYTOGENETIC ANALYSIS is performed to determine the presence or absence of genetic disease.

The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.

An assisted reproductive technique that includes the direct handling and manipulation of oocytes and sperm to achieve fertilization in vitro.

Endometrial implantation of EMBRYO, MAMMALIAN at the BLASTOCYST stage.

Preservation of cells, tissues, organs, or embryos by freezing. In histological preparations, cryopreservation or cryofixation is used to maintain the existing form, structure, and chemical composition of all the constituent elements of the specimens.

Minute cells produced during development of an OOCYTE as it undergoes MEIOSIS. A polar body contains one of the nuclei derived from the first or second meiotic CELL DIVISION. Polar bodies have practically no CYTOPLASM. They are eventually discarded by the oocyte. (from King & Stansfield, A Dictionary of Genetics, 4th ed)

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.

The entity of a developing mammal (MAMMALS), generally from the cleavage of a ZYGOTE to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the FETUS.

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).

A subphylum of chordates intermediate between the invertebrates and the true vertebrates. It includes the Ascidians.

An albumin obtained from the white of eggs. It is a member of the serpin superfamily.

Somewhat flattened, globular echinoderms, having thin, brittle shells of calcareous plates. They are useful models for studying FERTILIZATION and EMBRYO DEVELOPMENT.

Transport of the OVUM or fertilized ovum (ZYGOTE) from the mammalian oviduct (FALLOPIAN TUBES) to the site of EMBRYO IMPLANTATION in the UTERUS.

The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.

An early embryo that is a compact mass of about 16 BLASTOMERES. It resembles a cluster of mulberries with two types of cells, outer cells and inner cells. Morula is the stage before BLASTULA in non-mammalian animals or a BLASTOCYST in mammals.

The ratio of the number of conceptions (CONCEPTION) including LIVE BIRTH; STILLBIRTH; and fetal losses, to the mean number of females of reproductive age in a population during a set time period.

The potential of the FETUS to survive outside the UTERUS after birth, natural or induced. Fetal viability depends largely on the FETAL ORGAN MATURITY, and environmental conditions.

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.

Morphological and physiological development of EMBRYOS or FETUSES.

The fusion of a spermatozoon (SPERMATOZOA) with an OVUM thus resulting in the formation of a ZYGOTE.

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 three primary germinal layers (ECTODERM; ENDODERM; and MESODERM) developed during GASTRULATION that provide tissues and body plan of a mature organism. They derive from two early layers, hypoblast and epiblast.

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 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.

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).

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.

A reaction that severs one of the covalent sugar-phosphate linkages between NUCLEOTIDES that compose the sugar phosphate backbone of DNA. It is catalyzed enzymatically, chemically or by radiation. Cleavage may be exonucleolytic - removing the end nucleotide, or endonucleolytic - splitting the strand in two.

The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.

The chromosomal constitution of cells which deviate from the normal by the addition or subtraction of CHROMOSOMES, chromosome pairs, or chromosome fragments. In a normally diploid cell (DIPLOIDY) the loss of a chromosome pair is termed nullisomy (symbol: 2N-2), the loss of a single chromosome is MONOSOMY (symbol: 2N-1), the addition of a chromosome pair is tetrasomy (symbol: 2N+2), the addition of a single chromosome is TRISOMY (symbol: 2N+1).

An assisted fertilization technique consisting of the microinjection of a single viable sperm into an extracted ovum. It is used principally to overcome low sperm count, low sperm motility, inability of sperm to penetrate the egg, or other conditions related to male infertility (INFERTILITY, MALE).

An aquatic genus of the family, Pipidae, occurring in Africa and distinguished by having black horny claws on three inner hind toes.

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 outer of the three germ layers of an embryo.

An octamer transcription factor that is expressed primarily in totipotent embryonic STEM CELLS and GERM CELLS and is down-regulated during CELL DIFFERENTIATION.

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)

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.

A reaction that severs one of the sugar-phosphate linkages of the phosphodiester backbone of RNA. It is catalyzed enzymatically, chemically, or by radiation. Cleavage may be exonucleolytic, or endonucleolytic.

The condition of carrying two or more FETUSES simultaneously.

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.

An exotic species of the family CYPRINIDAE, originally from Asia, that has been introduced in North America. They are used in embryological studies and to study the effects of certain chemicals on development.

The process of germ cell development in the female from the primordial germ cells through OOGONIA to the mature haploid ova (OVUM).

Elements of limited time intervals, contributing to particular results or situations.

The middle germ layer of an embryo derived from three paired mesenchymal aggregates along the neural tube.

Proteins obtained from the ZEBRAFISH. Many of the proteins in this species have been the subject of studies involving basic embryological development (EMBRYOLOGY).

A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.

The process of cleaving a chemical compound by the addition of a molecule of water.

The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)

A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.

Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.

Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.

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.

Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.

Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.

A type of IN SITU HYBRIDIZATION in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei.

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.

The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.

The parts of a macromolecule that directly participate in its specific combination with another molecule.

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.

Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.

The rate dynamics in chemical or physical systems.

A proprotein convertase with specificity for the proproteins of PROALBUMIN; COMPLEMENT 3C; and VON WILLEBRAND FACTOR. It has specificity for cleavage near paired ARGININE residues that are separated by two amino acids.

A family of intracellular CYSTEINE ENDOPEPTIDASES that play a role in regulating INFLAMMATION and APOPTOSIS. They specifically cleave peptides at a CYSTEINE amino acid that follows an ASPARTIC ACID residue. Caspases are activated by proteolytic cleavage of a precursor form to yield large and small subunits that form the enzyme. Since the cleavage site within precursors matches the specificity of caspases, sequential activation of precursors by activated caspases can occur.

Factors that are involved in directing the cleavage and POLYADENYLATION of the of MESSENGER RNA near the site of the RNA 3' POLYADENYLATION SIGNALS.

Any member of the group of ENDOPEPTIDASES containing at the active site a serine residue involved in catalysis.

An immunoglobulin associated with MAST CELLS. Overexpression has been associated with allergic hypersensitivity (HYPERSENSITIVITY, IMMEDIATE).

Antigen-type substances that produce immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE).

Established cell cultures that have the potential to propagate indefinitely.

Proteins prepared by recombinant DNA technology.

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).

Tendency of the smooth muscle of the tracheobronchial tree to contract more intensely in response to a given stimulus than it does in the response seen in normal individuals. This condition is present in virtually all symptomatic patients with asthma. The most prominent manifestation of this smooth muscle contraction is a decrease in airway caliber that can be readily measured in the pulmonary function laboratory.

The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.

A short pro-domain caspase that plays an effector role in APOPTOSIS. It is activated by INITIATOR CASPASES such as CASPASE 9. Isoforms of this protein exist due to multiple alternative splicing of its MESSENGER RNA.

A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.

RNA that has catalytic activity. The catalytic RNA sequence folds to form a complex surface that can function as an enzyme in reactions with itself and other molecules. It may function even in the absence of protein. There are numerous examples of RNA species that are acted upon by catalytic RNA, however the scope of this enzyme class is not limited to a particular type of substrate.

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.

One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA; (DNA FRAGMENTATION); at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.

A form of hypersensitivity affecting the respiratory tract. It includes ASTHMA and RHINITIS, ALLERGIC, SEASONAL.

ENDOPEPTIDASES which have a cysteine involved in the catalytic process. This group of enzymes is inactivated by CYSTEINE PROTEINASE INHIBITORS such as CYSTATINS and SULFHYDRYL REAGENTS.

A family of enzymes that catalyze the endonucleolytic cleavage of RNA. It includes EC 3.1.26.-, EC 3.1.27.-, EC 3.1.30.-, and EC 3.1.31.-.

Substances that are recognized by the immune system and induce an immune reaction.

Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.

Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.

Hydrolases that specifically cleave the peptide bonds found in PROTEINS and PEPTIDES. Examples of sub-subclasses for this group include EXOPEPTIDASES and ENDOPEPTIDASES.

A mitochondrial cytochrome P450 enzyme that catalyzes the side-chain cleavage of C27 cholesterol to C21 pregnenolone in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP11A1 gene, catalyzes the breakage between C20 and C22 which is the initial and rate-limiting step in the biosynthesis of various gonadal and adrenal steroid hormones.

A family of SERINE ENDOPEPTIDASES isolated from Bacillus subtilis. EC 3.4.21.-

Cleavage of proteins into smaller peptides or amino acids either by PROTEASES or non-enzymatically (e.g., Hydrolysis). It does not include Protein Processing, Post-Translational.

Endopeptidases that are specific for AMYLOID PROTEIN PRECURSOR. Three secretase subtypes referred to as alpha, beta, and gamma have been identified based upon the region of amyloid protein precursor they cleave.

The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.

The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.

Washing liquid obtained from irrigation of the lung, including the BRONCHI and the PULMONARY ALVEOLI. It is generally used to assess biochemical, inflammatory, or infection status of the lung.

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.

A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC 3.4.21.4.

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 sum of the weight of all the atoms in a molecule.

Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.

Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.

A sub-subclass of endopeptidases that depend on an ASPARTIC ACID residue for their activity.

Subset of helper-inducer T-lymphocytes which synthesize and secrete the interleukins IL-4, IL-5, IL-6, and IL-10. These cytokines influence B-cell development and antibody production as well as augmenting humoral responses.

ENDOPEPTIDASES which use a metal such as ZINC in the catalytic mechanism.

A form of bronchial disorder with three distinct components: airway hyper-responsiveness (RESPIRATORY HYPERSENSITIVITY), airway INFLAMMATION, and intermittent AIRWAY OBSTRUCTION. It is characterized by spasmodic contraction of airway smooth muscle, WHEEZING, and dyspnea (DYSPNEA, PAROXYSMAL).

Granular leukocytes with a nucleus that usually has two lobes connected by a slender thread of chromatin, and cytoplasm containing coarse, round granules that are uniform in size and stainable by eosin.

Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.

Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.

Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.

Altered reactivity to an antigen, which can result in pathologic reactions upon subsequent exposure to that particular antigen.

Occurrence or induction of release of more ova than are normally released at the same time in a given species. The term applies to both animals and humans.

Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.

Proteins found in any species of virus.

RNA transcripts of the DNA that are in some unfinished stage of post-transcriptional processing (RNA PROCESSING, POST-TRANSCRIPTIONAL) required for function. RNA precursors may undergo several steps of RNA SPLICING during which the phosphodiester bonds at exon-intron boundaries are cleaved and the introns are excised. Consequently a new bond is formed between the ends of the exons. Resulting mature RNAs can then be used; for example, mature mRNA (RNA, MESSENGER) is used as a template for protein production.

Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.

A condition characterized by infiltration of the lung with EOSINOPHILS due to inflammation or other disease processes. Major eosinophilic lung diseases are the eosinophilic pneumonias caused by infections, allergens, or toxic agents.

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.

Post-transcriptional biological modification of messenger, transfer, or ribosomal RNAs or their precursors. It includes cleavage, methylation, thiolation, isopentenylation, pseudouridine formation, conformational changes, and association with ribosomal protein.

Cysteine proteinase found in many tissues. Hydrolyzes a variety of endogenous proteins including NEUROPEPTIDES; CYTOSKELETAL PROTEINS; proteins from SMOOTH MUSCLE; CARDIAC MUSCLE; liver; platelets; and erythrocytes. Two subclasses having high and low calcium sensitivity are known. Removes Z-discs and M-lines from myofibrils. Activates phosphorylase kinase and cyclic nucleotide-independent protein kinase. This enzyme was formerly listed as EC 3.4.22.4.

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.

The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.

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.

Enzyme systems containing a single subunit and requiring only magnesium for endonucleolytic activity. The corresponding modification methylases are separate enzymes. The systems recognize specific short DNA sequences and cleave either within, or at a short specific distance from, the recognition sequence to give specific double-stranded fragments with terminal 5'-phosphates. Enzymes from different microorganisms with the same specificity are called isoschizomers. EC 3.1.21.4.

The discharge of an OVUM from a rupturing follicle in the OVARY.

A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.

The specific failure of a normally responsive individual to make an immune response to a known antigen. It results from previous contact with the antigen by an immunologically immature individual (fetus or neonate) or by an adult exposed to extreme high-dose or low-dose antigen, or by exposure to radiation, antimetabolites, antilymphocytic serum, etc.

Enzymes that catalyze the transfer of multiple ADP-RIBOSE groups from nicotinamide-adenine dinucleotide (NAD) onto protein targets, thus building up a linear or branched homopolymer of repeating ADP-ribose units i.e., POLY ADENOSINE DIPHOSPHATE RIBOSE.

DNA TOPOISOMERASES that catalyze ATP-dependent breakage of both strands of DNA, passage of the unbroken strands through the breaks, and rejoining of the broken strands. These enzymes bring about relaxation of the supercoiled DNA and resolution of a knotted circular DNA duplex.

Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.

The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).

The process by which antigen is presented to lymphocytes in a form they can recognize. This is performed by antigen presenting cells (APCs). Some antigens require processing before they can be recognized. Antigen processing consists of ingestion and partial digestion of the antigen by the APC, followed by presentation of fragments on the cell surface. (From Rosen et al., Dictionary of Immunology, 1989)

Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.

Substances that augment, stimulate, activate, potentiate, or modulate the immune response at either the cellular or humoral level. The classical agents (Freund's adjuvant, BCG, Corynebacterium parvum, et al.) contain bacterial antigens. Some are endogenous (e.g., histamine, interferon, transfer factor, tuftsin, interleukin-1). Their mode of action is either non-specific, resulting in increased immune responsiveness to a wide variety of antigens, or antigen-specific, i.e., affecting a restricted type of immune response to a narrow group of antigens. The therapeutic efficacy of many biological response modifiers is related to their antigen-specific immunoadjuvanticity.

Compounds which inhibit or antagonize biosynthesis or actions of proteases (ENDOPEPTIDASES).

The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.

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.

A family of membrane-anchored glycoproteins that contain a disintegrin and metalloprotease domain. They are responsible for the proteolytic cleavage of many transmembrane proteins and the release of their extracellular domain.

Enzymes that catalyze the hydrolysis of the internal bonds and thereby the formation of polynucleotides or oligonucleotides from ribo- or deoxyribonucleotide chains. EC 3.1.-.

Physiologically inactive substances that can be converted to active enzymes.

The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.

Chromosome abnormalities in human embryos. (1/708)

The presence of numerical chromosome abnormalities in human embryos was studied using fluorescence in-situ hybridization with four or more chromosome-specific probes. When most cells of an embryo are analysed, this technique allows differentiation to be made between aneuploidy, mosaicism, haploidy and polyploidy. Abnormal types of fertilization, such as unipronucleated, tripronucleated zygotes and zygotes with uneven pronuclei, were studied using this technique. We have found a strong correlation between some types of dysmorphism with chromosomal abnormalities. In addition, the more impaired the development of an embryo, the more chromosomal abnormalities were detected in those embryos. Maternal age and other factors were linked to an increase in chromosome abnormalities (hormonal regimes, temperature changes), but not to intracytoplasmic sperm injection. (+info)

Temporal and spatial aspects of fragmentation in early human embryos: possible effects on developmental competence and association with the differential elimination of regulatory proteins from polarized domains. (2/708)

This study examined the relationship between blastomere fragmentation in cultured human embryos obtained by in-vitro fertilization and the effect of fragmentation on the distribution of the following eight regulatory proteins found to be: (i) localized in the mature oocyte in subplasmalemmal, polarized domains; and (ii) unequally inherited by the blastomeres during cleavage: leptin, signal transducer and activator of transcription 3 (STAT3), Bax, Bcl-x, transforming growth factor beta 2 (TGF beta 2), vascular endothelial growth factor (VEGF), c-kit and epidermal growth factor R (EGF-R). Four basic patterns of fragmentation were observed. The severity of the impact of each type of fragmentation on the affected blastomere(s) and the developmental competence of the embryo appeared to be a function of the unique temporal and spatial features associated with the particular fragmentation pattern(s) involved in each instance. The findings demonstrate that certain patterns of fragmentation can result in the partial or near total loss of the eight regulatory proteins from specific blastomeres and that the developmental potential of the affected embryo can be particularly compromised if it occurs during the 1- or 2-cell stages. In contrast, fragmentation from portions of a fertilized egg or a blastomere(s) in a 2-cell embryo that do not contain the protein domains, or the complete loss by fragmentation of a regulatory protein domain-containing blastomere after the 4-cell stage does not necessarily preclude continued development to the blastocyst, although the normality and developmental potential of the embryo may be compromised. The possible association between fragmentation and apoptosis was examined by annexin V staining of plasma membrane phosphatidylserine and TUNEL analysis of blastomere DNA. No direct correlation between fragmentation and apoptosis was found following the analyses of fragmented embryos with these two markers. However, while we suggest that changes in cell physiology unrelated to apoptosis are the more likely causes of fragmentation, we cannot exclude the possibility that fragmentation itself may be an initiator of apoptosis if critical ratios or levels of developmentally important proteins are altered by partial or complete elimination of their polarized domains. The findings are discussed with respect to the possible developmental significance of regulatory protein polarization in human oocytes and preimplantation stage embryos. (+info)

Spatially restricted expression of PlOtp, a Paracentrotus lividus orthopedia-related homeobox gene, is correlated with oral ectodermal patterning and skeletal morphogenesis in late-cleavage sea urchin embryos. (3/708)

Several homeobox genes are expressed in the sea urchin embryo but their roles in development have yet to be elucidated. Of particular interest are homologues of homeobox genes that in mouse and Drosophila are involved in patterning the developing central nervous system (CNS). Here, we report the cloning of an orthopedia (Otp)-related gene from Paracentrotus lividus, PlOtp. Otp is a single copy zygotic gene that presents a unique and highly restricted expression pattern. Transcripts were first detected at the mid-gastrula stage in two pairs of oral ectoderm cells located in a ventrolateral position, overlying primary mesenchyme cell (PMC) clusters. Increases in both transcript abundance and the number of Otp-expressing cells were observed at prism and pluteus stages. Otp transcripts are symmetrically distributed in a few ectodermal cells of the oral field. Labelled cells were observed close to sites of active skeletal rod growth (tips of the budding oral and anal arms), and at the juxtaposition of stomodeum and foregut. Chemicals known to perturb PMC patterning along animal-vegetal and oral-aboral axes altered the pattern of Otp expression. Vegetalization by LiCl caused a shift in Otp-expressing cells toward the animal pole, adjacent to shifted PMC aggregates. Nickel treatment induced expression of the Otp gene in an increased number of ectodermal cells, which adopted a radialized pattern. Finally, ectopic expression of Otp mRNA affected patterning along the oral-aboral axis and caused skeletal abnormalities that resembled those exhibited by nickel-treated embryos. From these results, we conclude that the Otp homeodomain gene is involved in short-range cell signalling within the oral ectoderm for patterning the endoskeleton of the larva through epithelial-mesenchymal interactions. (+info)

The centrosome-attracting body, microtubule system, and posterior egg cytoplasm are involved in positioning of cleavage planes in the ascidian embryo. (4/708)

Many kinds of animal embryos exhibit stereotyped cleavage patterns during early embryogenesis. In the ascidian Halocynthia roretzi, cleavage patterns are invariant but they are complicated by successive unequal cleavages that occur in the posterior region. Here we report the essential roles of a novel structure, called the centrosome-attracting body (CAB), which exists in the posterior pole cortex of cleaving embryos, in generating unequal cleavages. By removing and transplanting posterior egg cytoplasm and by treatment with sodium dodecyl sulfate, we demonstrated that loss of the CAB resulted in abolishment of unequal cleavage, while ectopic formation of the CAB caused ectopic unequal cleavages to occur. Experiments with a microtubule inhibitor demonstrated that the centrosome and nucleus were attracted toward the posterior cortex, where the CAB is located, by shortening of microtubule bundles formed between the centrosome and the CAB. Consequently, the mitotic apparatus was positioned asymmetrically, resulting in unequal cleavage. Immunohistochemistry provided evidence that a microtubule motor protein, a kinesin or kinesin-like molecule, may be associated with the CAB. Formation of the CAB during the early cleavage stage was resistant to treatment with the microtubule inhibitor. In contrast, the integrity of the CAB was lost upon treatment with a microfilament inhibitor. We propose that the CAB plays key roles in the orientation and positioning of cleavage planes during unequal cell division. (+info)

Identification of two major histocompatibility complex class Ib genes, Q7 and Q9, as the Ped gene in the mouse. (5/708)

The Ped (preimplantation embryonic development) gene influences the rate of preimplantation embryonic development and subsequent embryonic survival. The protein product of the Ped gene, the Qa-2 protein, is a major histocompatibility complex (MHC) class Ib protein. There are two alleles of the Ped gene, fast (Qa-2 [+]) and slow (Qa-2 [-]). Qa-2 is encoded by four very similar MHC class Ib genes: Q6, Q7, Q8, and Q9. Recent research in our laboratory has shown that the Ped phenotype is potentially encoded by the Q7 and/or Q9 gene because the Q7 and Q9 genes, but not the Q6 or Q8 gene, are expressed during preimplantation mouse embryonic development. In this study we utilized microinjection of transgenes to assess the functional roles of both the Q7 and Q9 genes in control of the rate of preimplantation development. The Q7 gene, the Q9 gene, and a combination of the Q7 and Q9 genes were microinjected into Ped slow zygotes, and the Ped phenotype and cell surface expression of Qa-2 protein were assayed after a 72-h or 96-h incubation period. We found that the microinjected individual Q7 and Q9 genes increased the rate of preimplantation development. Simultaneous injection of the Q7 and Q9 genes did not have a synergistic effect on the Ped phenotype. Microinjection of the Q7 and/or Q9 genes resulted in protein expression in 10-25% of the microinjected embryos. These results show that both the Q7 and Q9 genes encode the mouse Ped phenotype. (+info)

Cytoskeletal mechanisms of ooplasmic segregation in annelid eggs. (6/708)

Annelid embryos are comprised of yolk-deficient animal and yolk-filled vegetal blastomeres. This "unipolar" organization along the animal-vegetal axis (in terms of ooplasmic distribution) is generated via selective segregation of yolk-free, clear cytoplasm to the animal blastomeres. The pathway that leads to the unipolar organization is different between polychaetes and clitellates (i.e., oligochaetes and hirudinidans). In polychaetes, the clear cytoplasm domain, which is established through ooplasmic segregation at the animal side of the egg, is simply cut up by unequal equatorial cleavage. In clitellates, localization of clear cytoplasm to animal blastomeres is preceded by unification of the initially separated polar domains of clear cytoplasm, which result from bipolar ooplasmic segregation. In this article, I have reviewed recent studies on cytoskeletal mechanisms for ooplasmic localization during early annelid development. Annelid eggs accomplish ooplasmic rearrangements through various combinations of three cytoskeletal mechanisms, which are mediated by actin microfilaments, microtubules and mitotic asters, respectively. One of the unique features of annelid eggs isthat a homologous process is driven by distinct cytoskeletal elements. Annelid eggs may provide an intriguing system to investigate not only mechanical aspects of ooplasmic segregation but also evolutionary divergence of cytoskeletal mechanisms that operate in a homologous process. (+info)

Characterization of novel F-actin envelopes surrounding nuclei during cleavage of a polychaete worm. (7/708)

F-actin accumulations and their possible functions were investigated during cleavage of the polychaete Ophryotrocha puerilis. Unusual cytoplasmic accumulations of F-actin were detected which have never been described before in animal embryos. As shown by TRITC-phalloidin labeling, envelopes of F-actin surrounded late prophase nuclei for a short period of time. DTAF-immunofluorescence of beta-tubulin showed that the F-actin envelope was closely associated with microtubules of the developing spindle apparatus. However, experimental disassembly of microtubules by nocodazole did not prevent the assembly of the F-actin envelope. Disturbance of F-actin envelope formation by cytochalasin B did not alter the course of mitotic events, i.e. position of the nuclei and orientation of the spindle apparatus were not affected, although the respective blastomeres remained uncleaved. However, disassembly of the F-actin envelope correlated temporally with breakdown of the nuclear envelope. Therefore, it is suggested that this new structure plays a role in fragmentation of the nuclear envelope during cleavage of Ophryotrocha puerilis. (+info)

Comparison of human blastulation rates and total cell number in sequential culture media with and without co-culture. (8/708)

Recent interest in delayed embryo transfers necessitated the evaluation of two improved in-vitro systems that could generate viable blastocysts. A total of 178 two-pronucleated embryos (entire cohorts) from 19 patients was cultured in IVF50 medium (100 microl) under oil for 24 h until day 2. Each patient's day 2 embryos were then equally allotted to two in-vitro systems. Embryos in system A were grown until the morning of day 3 on Vero cells covered with IVF50 medium (100 microl) under oil. The medium was then replaced on day 3 with a 1:1 mixture (100 microl) of IVF50:S2 medium and on day 4 with S2 medium only. The same culture protocol was used for system B without Vero cells. Throughout the 5 days all dishes were housed in sealed humidified modular chambers containing a triple gas atmosphere. Separately, 175 spare embryos from 80 patients were grown in system A and B up to days 6 and 7 for total cell number (TCN) analysis. Blastulation rates were not significantly different between system A and B (67.4 versus 68.5%; P > 0.01) although co-cultured embryos cleaved slightly faster by day 4. The overall pregnancy and implantation rates were 52.0% and 32.1% for the 19 patients each of whom received a mixed cohort of three day 5 embryos from both systems. TCN values for the day 6 and 7 blastocysts from both systems were high and increased steadily from days 6-7 and from expanded to hatching stages. There were no significant differences in TCN for day 6 expanded blastocysts between the two systems although day 6 hatching and hatched co-cultured blastocysts had greater values than non-co-cultured blastocysts (246.0 +/- 18.5 and 236.7 +/- 17.8 versus 173.0 +/- 13.5 and 166.5 +/- 16.0; P < 0.01). The results demonstrated that the culture protocol using the sequential IVF50-S2 media combination was a good substitute for Vero cell co-culture for the transfer of viable day 3-6 embryos. (+info)

This mitosis is also known as cleavage. A hollow cavity forms marking the blastocyst stage. (day 1.5-3 of fertilization.) The ... Fertilization of the ovum to form a new human organism, the human zygote. (day 1 of fertilization) The zygote undergoes mitotic ... Wagner F, Erdösová B, Kylarová D (December 2004). "Degradation phase of apoptosis during the early stages of human metanephros ...

https://en.wikipedia.org/wiki/Timeline_of_human_prenatal_development

Fertilization occurs when the sperm reaches the ovum. The zygote experiences radial holoblastic cleavage and eventually forms ... Euplectella experiences two main life stages: the larval stage or the adult stage. In the larval stage, the larvae is free ... In the adult stage, Euplectella are sessile and attached firmly to rocks through spicules. It is unclear how long Euplectella ...

https://en.wikipedia.org/wiki/Euplectella

Usually even before its liberation, the ovum initiates cleavage processes in which it becomes completely pinched through at the ... Development beyond this 256-cell stage has not yet been observed. Trichoplax lack a homologue of the Boule protein that appears ... Once maturation of the ovum is complete, the rest of the animal degenerates, liberating the ovum itself. Small, unciliated ... In the protected interior space, the ventral cells form an ovum surrounded by a special envelope, the fertilisation membrane; ...

https://en.wikipedia.org/wiki/Trichoplax

The ova is yellowish in color. The egg is about 70-85 μm long by 44 μm wide, and the early stages of cleavage contain between ... and L2 juvenile stages by feeding on bacteria in the dung. The L1 stage usually occurs within four to six days under the ... "The role of the sheath in resistance of Haemonchus contortus infective stage larvae to proteolytic digestion". Veterinary ...

https://en.wikipedia.org/wiki/Haemonchus_contortus

The different cells derived from cleavage, up to the blastula stage, are called blastomeres. Depending mostly on the amount of ... The inner cell mass remains in contact, however, with the trophoblast at one pole of the ovum; this is named the embryonic pole ... Meroblastic cleavage occurs in animals whose eggs have more yolk (i.e. birds and reptiles). Because cleavage is impeded in the ... In holoblastic eggs, the first cleavage always occurs along the vegetal-animal axis of the egg, and the second cleavage is ...

https://en.wikipedia.org/wiki/Animal_embryonic_development

... cleavage stage, ovum MeSH A16.254.300.600.274 - blastula MeSH A16.254.300.600.550 - morula MeSH A16.254.300.800 - yolk sac MeSH ... cleavage stage, ovum MeSH A16.254.270.274 - blastula MeSH A16.254.270.550 - morula MeSH A16.254.283 - cloaca MeSH A16.254.300 ...

https://en.wikipedia.org/wiki/List_of_MeSH_codes_(A16)

The germinal stage takes around 10 days. During this stage, the zygote begins to divide, in a process called cleavage. A ... With the sperm adhered to the ovum, the third process of acrosomal reaction takes place; the front part of the spermatozoan ... Cleavage itself is the first stage in blastulation, the process of forming the blastocyst. Cells differentiate into an outer ... The germinal stage refers to the time from fertilization through the development of the early embryo until implantation is ...

https://en.wikipedia.org/wiki/Human_embryonic_development

"blastocoel...[blaso- + -coele] the fluid-filled cavity of the mass of cells (blastula) produced by cleavage of fertilized ovum ... cell stage is considered a blastula as the blastocoel in the embryo becomes apparent during this stage. The fluid-filled cavity ... At this stage there is no cavity within the morula; the embryo is still a ball of dividing cells. In a process called ... At this stage in mammals the blastula develops into the blastocyst containing an inner cell mass, and outer trophectoderm. It ...

https://en.wikipedia.org/wiki/Blastocoel

Soma line is the vegetative stage. During early cleavage stages of the embryo limited chromosomes are eliminated. The number of ... In the formation ova of the females the 1st ovarian division is monocentric mitosis, the maternal and paternal homologous ... In the next stage of cleavage one paternal X chromosome is eliminated. Hence female soma line cells have 3 pairs of autosomes ... Some special chromosomes called limited chromosomes are present in certain stages. The zygote has 3 pairs of autosomes a one or ...

https://en.wikipedia.org/wiki/Sciara_(fly)

The germinal stage takes around 10 days. During this stage, the zygote begins to divide, in a process called cleavage. A ... Fertilisation occurs when the sperm cell successfully enters and fuses with an egg cell (ovum). The genetic material of the ... Briefly, embryonic development have four stages: the morula stage, the blastula stage, the gastrula stage, and the neurula ... The egg becomes a zygote and the germinal stage of embryonic development begins. The germinal stage refers to the time from ...

https://en.wikipedia.org/wiki/Development_of_the_human_body

Spermatozoa fuse with the ova in the fertilisation duct, where the zygotes are produced. The zygote undergoes holoblastic and ... However, humans can also act as secondary hosts, which is a more pathological, harmful stage triggered by oral contamination. ... unequal cleavage resulting in three cell types, small, medium and large (micromeres, mesomeres, megameres). Megameres develop ... Humans are colonised by the larval stage, the cysticercus, from undercooked pork or other meat. Each microscopic cysticercus is ...

https://en.wikipedia.org/wiki/Taenia_solium

Temporary gonoducts (ducts from which the ova or sperm are emitted), one per gonad, are built when the ova and sperm are ready ... This larval stage is unique in that there are no Hox genes involved during development, which are only found in the juveniles ... The fertilized egg divides by spiral cleavage and grows by determinate development, in which the fate of a cell can usually be ... The planuliform larva stage may be short-lived and lecithotrophic ("yolky") before becoming a juvenile, or may be ...

https://en.wikipedia.org/wiki/Nemertea

"Zygotes segregate entire parental genomes in distinct blastomere lineages causing cleavage-stage chimerism and mixoploidy". ... Fertilisation occurs when an ovum fuses with a sperm, forming a zygote. Normally, the genomes of the two parents assort into ...

https://en.wikipedia.org/wiki/Heterogonesis

Stage of a cell division Metaphase - Stage of cell division Mitosis - Process in which replicated chromosomes are separated ... constricting the cell membrane to form a cleavage furrow. Continued hydrolysis causes this cleavage furrow to ingress (move ... for example in oogenesis in animals the ovum takes almost all the cytoplasm and organelles. This leaves very little for the ... Diploid Telophase - Final stage of a cell division for eukaryotic cells both in mitosis and meiosis Prophase - First phase of ...

https://en.wikipedia.org/wiki/Cytokinesis

... of a motile stage. The zygote or the ovum itself or the sessile organic vessel containing the developing embryo may be called ... The yolk is evenly distributed, so the cleavage of the egg cell cuts through and divides the egg into cells of fairly similar ... In cnidarians, this stage is called the planula, and either develops directly into the adult animals or forms new adult ... The fetus instead develops as a plate-like structure on top of the yolk mass, and only envelopes it at a later stage. A portion ...

https://en.wikipedia.org/wiki/Egg

This stage has also been referred to as the pre-embryo in legal discourses including relevance to the use of embryonic stem ... In the fertilized daughter, DNA is then replicated in the two separate pronuclei derived from the sperm and ovum, making the ... in a process called cleavage. After four divisions, the conceptus consists of 16 blastomeres, and it is known as the morula. ... Between the stages of fertilization and implantation, the developing embryo is sometimes termed as a preimplantation-conceptus ...

https://en.wikipedia.org/wiki/Zygote

Coeloblastula is the next stage of development for eggs that undergo this radial cleavage. In mammals, because the isolecithal ... Isolecithal (Greek iso = equal, lekithos = yolk) refers to the even distribution of yolk in the cytoplasm of ova of mammals and ... and rotational holoblastic cleavage. These holoblastic cleavage planes pass all the way through isolecithal zygotes during the ... In the absence of a large concentration of yolk, four major cleavage types can be observed in isolecithal cells: radial ...

https://en.wikipedia.org/wiki/Isolecithal

Yolk cells travel in a duct system to the oviduct, where, in a modified region, the ovum is enclosed in a shell with yolk cells ... After the scolex has differentiated and matured in the larval stage, growth will stop until a vertebrate eats the intermediate ... The initial six-hooked embryo, known as an oncosphere or hexacanth, forms through cleavage. In the order Pseudophyllidea, it ... Eucestoda ontogenesis continues through metamorphosing in different larval stages inside different hosts. ...

https://en.wikipedia.org/wiki/Eucestoda

Holoblastic cleavage can be radial (see: Radial cleavage), spiral (see: Spiral cleavage), bilateral (see: Bilateral cleavage), ... In the first stage, the semen predominates. In the second stage, the embryo is filled with blood. In the third stage, the main ... Until the birth of modern embryology through observation of the mammalian ovum by Karl Ernst von Baer in 1827, there was no ... Meroblastic cleavage can be bilateral (see: Bilateral cleavage), discoidal (see: Discoidal cleavage), or centrolecithal (see: ...

https://en.wikipedia.org/wiki/Embryology

... stages of meiosis. The long period of meiotic arrest at the four chromatid dictyate stage of meiosis may facilitate ... Germ cell specification begins during cleavage in many animals or in the epiblast during gastrulation in birds and mammals. ... ovum). The unfertilized egg of most animals is asymmetrical: different regions of the cytoplasm contain different amounts of ... The mouse oocyte in the dictyate (prolonged diplotene) stage of meiosis actively repairs DNA damage, whereas DNA repair was not ...

https://en.wikipedia.org/wiki/Germ_cell

... cleavage) (photograph). By 8-9 hours, it has reached the 64-cell stage. Some molecular and histological evidence suggests the ... In section, they are very different, with the ovaries densely filled with nutrient-packed ova (see ovum and photograph) and the ... To this stage ,the larva has been virtually transparent, but the posterior section is now opaque with the initial development ... Juveniles of A. planci that had reached the stage of feeding on coral were then reared for some years in the same large closed- ...

https://en.wikipedia.org/wiki/Crown-of-thorns_starfish

It is optimally performed at the 6- to 8-cell stage, where it can be used as an expansion of IVF to increase the number of ... Dolly's embryo was created by taking the cell and inserting it into a sheep ovum. It took 435 attempts before an embryo was ... and Parton is known for her ample cleavage. The modern cloning techniques involving nuclear transfer have been successfully ... At an early growth stage when colonies consist of only a few cells, sterile polystyrene rings (cloning rings), which have been ...

https://en.wikipedia.org/wiki/Cloning

The main durations of embryo culture are until cleavage stage (day two to four after co-incubation) or the blastocyst stage ( ... removing an ovum or ova (egg or eggs) from their ovaries and letting sperm fertilise them in a culture medium in a laboratory. ... among births having from embryos cultured until the blastocyst stage compared with cleavage stage. Laboratories have developed ... On the contrary, for women of advanced maternal age, PGS with cleavage-stage biopsy significantly lowers the live birth rate. ...

https://en.wikipedia.org/wiki/In_vitro_fertilisation

The first stage of prophase I is the leptotene stage, also known as leptonema, from Greek words meaning "thin threads".: 27 In ... which enlarges to become an ovum. Therefore, in females each primary oocyte that undergoes meiosis results in one mature ovum ... Nuclear envelopes re-form and cleavage or cell plate formation eventually produces a total of four daughter cells, each with a ... 27 is the stage at which all autosomal chromosomes have synapsed. In this stage homologous recombination, including chromosomal ...

https://en.wikipedia.org/wiki/Meiosis

After the fertilization, the cleavage of the embryo leads to the formation of the germinal disc. As food, the chicken egg yolk ... All bony fish, some sharks and rays have yolk sacs at some stage of development, with all oviparous fish retaining the sac ... The yolk mass, together with the ovum proper (after fertilization, the embryo) are enclosed by the vitelline membrane, whose ... contrary to the claim that the avian ovum (in strict sense) and its yolk are a single giant cell. ...

https://en.wikipedia.org/wiki/Yolk

The oral-aboral axis is specified early in cleavage, and the left-right axis appears at the late gastrula stage. In most cases ... The transparency of the urchin's eggs enabled them to be used to observe that sperm cells actually fertilize ova. They continue ... In the larval stages, the adult rudiment grows from the left coelomic pouch; after metamorphosis, that rudiment grows to become ... During cleavage, mesoderm and small micromeres are specified. At the end of gastrulation, cells of these two types form ...

https://en.wikipedia.org/wiki/Sea_urchin

Both of these systems use a two-stage filtration process, in which fluid and waste products are first extracted and these are ... Most polychaetes whose reproduction has been studied lack permanent gonads, and it is uncertain how they produce ova and sperm ... Hence this development pattern is often described as "spiral determinate cleavage". The term originated from Jean-Baptiste ... When their cells divide after the 4-cell stage, descendants of these four cells form a spiral pattern. In these phyla the " ...

https://en.wikipedia.org/wiki/Annelid

The Spiralia are a large group of protostomes that develop by spiral cleavage in the early embryo. The Spiralia's phylogeny has ... The blastula is a stage in embryonic development that is unique to animals, allowing cells to be differentiated into ... non-motile gametes are ova. These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In ... Valentine, James W. (July 1997). "Cleavage patterns and the topology of the metazoan tree of life". PNAS. 94 (15): 8001-8005. ...

https://en.wikipedia.org/wiki/Animal

After the stages of resection, strand invasion and DNA synthesis, the DSBR and SDSA pathways become distinct. The DSBR pathway ... This cleavage is done by RuvAB complex interacting with RuvC, which together form the RuvABC complex. RuvC is an endonuclease ... In turn, nondisjunction can cause sperm and ova to have too few or too many chromosomes. Down's syndrome, which is caused by an ... Mimitou EP, Symington LS (May 2009). "Nucleases and helicases take center stage in homologous recombination". Trends in ...

https://en.wikipedia.org/wiki/Homologous_recombination

Errors in maternal ovum also occur, but at a lower rate than in paternal sperm. The types of mutations that occur also tend to ... The ZFN editing complex consists of a zinc finger protein (ZFP) and a restriction enzyme cleavage domain. The ZNP domain can be ... Germline mutations can occur before fertilization and during various stages of zygote development. When the mutation arises ... Endogenous mutations are more prominent in sperm than in ova. This is because spermatocytes go through a larger number of cell ...

https://en.wikipedia.org/wiki/Germline_mutation

Most species use sexual reproduction, releasing sperm cells into the water to fertilize ova that in some species are released ... ISBN 978-1-84407-527-0. Jacobson N (2000). Cleavage. Rutgers University Press. p. 62. ISBN 978-0-8135-2715-4. "Sponges". ... while in larval stage of life they are motile . Although there are freshwater species, the great majority are marine (salt- ...

https://en.wikipedia.org/wiki/Sponge

She is the director of the drama club and during times on stage she has to be very forceful in order to get a good response out ... Yuu Kashiwagi (栢木優雨, Kashiwagi Yū) Voiced by: Shion Hondaeri (PC), Ai Shimizu (PSP), Mana Hirata (OVA) Yuu is a new student in ... Throughout the anime, willing suspension of disbelief is employed, as there are severally scenes where Mizuho shows cleavage ( ... Despite being very nervous on the stage, but she is selected for the leading role at the school festival by Kei, who is the ...

https://en.wikipedia.org/wiki/List_of_Otome_wa_Boku_ni_Koishiteru_characters

Full-length OPN (OPN-FL) can be modified by thrombin cleavage, which exposes a cryptic sequence, SVVYGLR on the cleaved form of ... The secreted form of Opn (Opn-s) plays a proinflammatory role during allergen sensitization (OVA/Alum), as neutralization of ... and disease stage-specific targeting. Although the exact mechanisms of osteopontin signaling in PDAC are unknown, it binds to ... an inhibition regulated by PHEX cleavage of ASARM". Journal of Bone and Mineral Research. 23 (10): 1638-1649. doi:10.1359/jbmr. ...

https://en.wikipedia.org/wiki/Osteopontin

At this stage the pentaradial symmetry develops. A plankton-eating larva, living and feeding in the water column, is considered ... The large size and the transparency of the eggs enables the observation of sperm cells in the process of fertilising ova. The ... On fracturing such rock, paleontologists can observe distinctive cleavage patterns and sometimes even the intricate internal ... Echinoderms have secondary radial symmetry in portions of their body at some stage of life, most likely an adaptation to a ...

https://en.wikipedia.org/wiki/Echinoderm

The authors found this surprising, since nemertines have spiral cleavage in the early stages of cell division and form a ... Ripe gametes (ova or sperm) float from the gonads into the main coelom and then exit into the mantle cavity. The larvae of ... Hence radial cleavage does not imply that brachiopods are affiliated with deuterostomes. The traditional view is that the ... The gonads are masses of developing gametes (ova or sperm), and most species have four gonads, two in each valve. Those of ...

https://en.wikipedia.org/wiki/Brachiopod

The different stages of mitosis all together define the mitotic phase of an animal cell cycle-the division of the mother cell ... The zygote undergoes a rapid multiple rounds of mitotic cell period of cell divisions called cleavage, which forms a ball of ... The smaller, motile gametes are spermatozoa and the larger, non-motile gametes are ova. These fuse to form zygotes, which ... During the third stage of photosynthesis, the movement of protons down their concentration gradients from the thylakoid lumen ...

https://en.wikipedia.org/wiki/Biology

It has reached the blastocyst stage at the time of implantation: this is when pregnancy begins. The loss of the corpus luteum ... The follicle that reaches maturity is called an antral follicle, and it contains the ovum (egg cell). The theca cells develop ... In the corpus luteum, cholesterol side-chain cleavage enzyme converts cholesterol to pregnenolone, which is converted to ... Menopause is preceded by a stage of hormonal changes called perimenopause. Eumenorrhea denotes normal, regular menstruation ...

https://en.wikipedia.org/wiki/Menstrual_cycle

The space within an ovum or immature ovum is located is the cell-nest. The cumulus-oocyte complex contains layers of tightly ... The oocyte is arrested in Meiosis II at the stage of metaphase II and is considered a secondary oocyte. Before ovulation, the ... "XPACE4 is a localized pro-protein convertase required for mesoderm induction and the cleavage of specific TGFbeta proteins in ... In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female ...

https://en.wikipedia.org/wiki/Oocyte

The corpus luteum is the last stage of the ovarian follicles' lifecycle. It has an important role in secreting estrogen and ... the ovum is not released from the ovary during menstrual cycle), hyperandrogenism (increased levels of androgen hormones, such ... "cFLIP regulates death receptor-mediated apoptosis in an ovarian granulosa cell line by inhibiting procaspase-8 cleavage". The ... Follicular atresia occurs throughout all stages of follicular development, until the follicular reserve is completely exhausted ...

https://en.wikipedia.org/wiki/Follicular_atresia

Cleavage Stage, Ovum A16.254.270 A16.166. A16.254.300.600. Cloaca A16.254.283 A16.178. Cloxacillin D2.886.675.966.500.750. ... Ovum A16.631 A16.690. Oxacillin D2.886.675.966.500.750.625 D2.886.108.750.625. D4.75.80.875.99.221.750.625. Papillary Muscles ...

https://decs.bvs.br/P/mnchg2008.htm

The zygote is the new cell, which is referred to as the fertilized ovum. Following the fertilization ... cleavage, gastrulation and organogenesis. The process of fertilization involves the fusion of a haploid female and male gamete ... the process of embryogenesis has four stages: fertilization, ... Embryo at stage after the Blastula. Stage in Embryogenesis. ... In every coelomate that sexually reproduces, the process of embryogenesis has four stages: fertilization, cleavage, ...

http://www.differencebetween.net/science/biology-science/difference-between-blastula-and-gastrula/

Note the smaller polar body between the two blastomeres at the upper margin of the cleavage plane. The larger polar body below ... Stage 1 / 1 day Stage 2 / 2-3 days Stage 3-1 / 4 days Stage 3-2 / 4-5 days Stage 4 / 6 days Stage 5a-1 / 7 days Stage 5a-2 / 8 ... Stage 5c / 12 days Stage 6 / 13-17 days Stage 7 / 16-19 days Stage 8 / 23 days Stage 9 / 25 days Stage 10 / 28 days Stage 11 / ... Stage 13 / 32 days Stage 14 / 33 days Stage 15 / 36 days Stage 16 / 39 days Stage 17 / 41 days Stage 18 / 44 days Stage 19 / 45 ...

https://affiliate.ehd.org/virtual-human-embryo/figure.php?stage=2&figure=66&search=2

Cleavage Stage, Ovum. J. S. Kanodia, Kim, Y., Tomer, R., Khan, Z., Chung, K., Storey, J. D., Lu, H., Keller, P. J., and ...

https://lsi.princeton.edu/research/publications?f%5Bauthor%5D=1292&s=keyword&o=asc

the two combined ova will act as a single zygote that has already achieved the first cleavage division or 2-cell stage of ... This allows the unfertilized ovum to exit the vagina before menstruation it is, therefore, possible for an ovum collision to ... 2 ova squishing together. Ive met the anon who commissioned these on /d/. I dont get it, but you get used to that on /d/.. ... Are those supposed to be clits or ovaries or what? A cross section of the anus and vagina? A zygote in its 2 cell stage? I do ...

https://boards.4chan.org/u/thread/3769895

Cleavage Stage, Ovum Entry term(s). Cleavage Stages, Ovum Ovum Cleavage Stage Ovum Cleavage Stages Ovum Segmentation Stage Ovum ... Cleavage Stages, Ovum. Ovum Cleavage Stage. Ovum Cleavage Stages. Ovum Segmentation Stage. Ovum Segmentation Stages. ... Cleavage Stage, Ovum - Preferred Concept UI. M0004547. Scope note. The earliest developmental stage of a fertilized ovum ( ... Each cleavage or segmentation yields two BLASTOMERES of about half size of the parent cell. This cleavage stage generally ...

https://decs.bvsalud.org/en/ths/resource/?id=2995

https://decs2014.bvsalud.org/E/mnchg2008.htm

https://decs2020.bvsalud.org/P/mnchg2008.htm

https://decs2013.bvsalud.org/E/mnchg2008.htm

https://decs2015.bvsalud.org/P/mnchg2008.htm

https://decs2017.bvsalud.org/P/mnchg2008.htm

https://decs2008.bvsalud.org/E/mnchg2008.htm

https://decs2012.bvsalud.org/E/mnchg2008.htm

https://decs2011.bvsalud.org/I/mnchg2008.htm

https://decs2018.bvsalud.org/E/mnchg2008.htm

https://decs2009.bvsalud.org/I/mnchg2008.htm

https://decs2019.bvsalud.org/P/mnchg2008.htm

https://decs2016.bvsalud.org/I/mnchg2008.htm

https://decs2010.bvsalud.org/E/mnchg2008.htm

Cleavage Stage Ovum. Click "Why?" to see why a person matched the search. ...

https://profiles.ouhsc.edu/search/default.aspx?searchtype=people&searchfor=Cleavage%20Stage,%20Ovum&perpage=15&offset=0&new=true

2. An early embryonic form produced by cleavage of a fertilized ovum and consisting of a spherical layer of cells surrounding a ... 3. An animal embryo at the stage immediately following the division of the fertilized egg cell, consisting of a ball-shaped ... 1. An embryo at an early stage of development, consisting of a hollow ball of cells.. ...

https://wordinfo.info/unit/1999/page:6

of uteri showing early cleavage stages (mitosis). Ascaris megalocephala embryology. Sec. of uteri showing later cleavage stages ... of uteri showing entrance and modification of sperm in ova Ascaris megalocephala embryology. Sec. of uteri showing maturation ... Mitotic stages in smear of red bone marrow of mammal * Meiotic (maturation) stages in testis of mouse, sec. iron hematoxyline ... stages (meiosis). Polar bodies can be seen. Ascaris megalocephala embryology. Sec. of uteri showing ova with male and female ...

https://www.astroshop.it/zoologia/lieder-citologia-persone-animali-e-piante-25-preparati-/p,54163

Cleavage Stage, Ovum. *Cloaca. *Embryo, Mammalian. *Embryo, Nonmammalian. *Fetus. *Germ Layers. *Gestational Sac ...

https://connects.catalyst.harvard.edu/Profiles/display/Concept/Vitelline%20Duct

Cleavage Stage, Ovum Female Fertilization Fertilization in Vitro Follicular Fluid - metabolism Growth Hormone - therapeutic use ... The review presents the main stages in the development of hepatitis C antiviral therapy, the efficacy of various treatment ... and cleavage in vitro. Further, the quality of embryos, development of the endometrium, rate of clinical pregnancy, and serum ...

https://arctichealth.org/en/list?q=topic%3A%22Recombinant+Proteins+-+therapeutic+use%22&p=1&ps=&sort=title_sort+asc

... the cavity formed by the arrangement of the cells in segmentation or cleavage of the ovum; the cavity of the blastosphere. In ... the gastrula stage, the segmentation cavity in which the mesoblast is ... cell cleavage; cell multiplication; endogenous cell formation. [1913 Webster] {Segmentation cavity} (Biol.), ... Segmentation of the ovum, or Egg cleavage (Biol.), the process by which the embryos of all the higher plants and animals are ...

http://kamus.landak.com/cari?emang=Segmentation+sphere

Outcomes of vitrified early cleavage-stage and blastocyst-stage embryos in a cryopreservation program: evaluation of 3,150 ... The linear regression model considering embryo developmental stage, ovum donation or patients own oocytes, and hormonal ... OBJECTIVE: To assess the outcomes achieved after Cryotop vitrification of both early cleavage and blastocyst-stage embryos and ... to determine whether the embryo developmental stage and embryo quality as well as the origin of the embryos (ovum donation ...

https://pesquisa.bvsalud.org/economia/?lang=pt&q=au:Santos,+Maria+Jos%C3%A9

These stages are depicted in Fig. 35.1. Basically, the earlier the fertilized ovum divides, the more separate the twins. ... Cleavage prior to development of an inner cell mass will result in two placentas, two sets of membranes and two fetuses, ... However, it is clear that division of the fertilized ovum at specific early stages of development is responsible for the ... Twins may arise from one of two mechanisms: division of a single fertilized ovum into two embryos ("identical" or monozygotic ...

https://www.pediagenosis.com/2018/11/multifetal-pregnancy.html

It is produced by cleavage of a fertilized ovum and consists of a spherical layer of around 128 cells with a large fluid-filled ... The blastula (from Greek βλαστός (blastos), meaning "sprout") is an early stage of embryonic development in animals. It is also ...

https://rulesareforrobots.com/tag/glue/

The zygote begins a process of cleavage that yields a growing and developing embryo, which progresses through th stages of ... One: The ,inception of life pccurs with the union of a sperm and an ovum, forming a zygote which carries the full genetic code ... has reached the stage of brain stem death, he is considered to have withdrawn from life, and certain rulings of the dead are ... Three: When it arrives at the spirit-breathing stage, the time of which is subject to controversy, being either forty or 120 ...

https://www.islamstickers.uk/forum/threads/human-life-its-inception-and-end-as-viewed-by-islam.43/

The ovum Buy Valium Europe contains one or if this lip possessed a hypoblast, though somites, and 24th 981. Buy Diazepam With ... The absorption spectrum is for the area thirteen or cleavage. This Order Alprazolam manner, or decreased because the forces of ... Extremity, and 32 -cell stage front there is also seems, made the foot growths and ctphonantes. Or smaller fragments the pars ... From a spherical to be they polzl, and separated by the ovum of two tail regions of cells. That they also ex- large extent at ...

https://goldenowlhunt.com/xn348ox1xc

The zygote is the new cell, which is referred to as the fertilized ovum. (differencebetween.net)
Following the fertilization event, the cleavage process involves the rapid division of the zygote, into many cells. (differencebetween.net)
A zygote in its 2 cell stage? (4chan.org)
The earliest developmental stage of a fertilized ovum ( ZYGOTE ) during which there are several mitotic divisions within the ZONA PELLUCIDA . (bvsalud.org)
One: The ,inception of life pccurs with the union of a sperm and an ovum, forming a zygote which carries the full genetic code of the human ace in general and of the particular individual, who is differerent from all others throughout the ages. (islamstickers.uk)
The zygote begins a process of cleavage that yields a growing and developing embryo, which progresses through th stages of gestation towards birth. (islamstickers.uk)
During cleavage, the zygote rapidly divides into multiple cells without increasing in size. (umn.edu)
The entity of a developing mammal (MAMMALS), generally from the cleavage of a ZYGOTE to the end of embryonic differentiation of basic structures. (musc.edu)
The egg is now referred to as a zygote as the cells split in a process known as cleavage and the start of embryonic development. (socialbaby.com)

Twins may arise from one of two mechanisms: division of a single fertilized ovum into two embryos ( "identical" or monozygotic twins ) or fertilization of two separate ova ( "fraternal" or dizygotic twins ). (pediagenosis.com)
We compared the pregnancy and live birth rates following transfer of early-stage embryos or blastocysts produced by somatic cell nuclear transfer using in vitro -matured oocytes. (cambridge.org)
Next, 71 early-stage embryos were surgically transferred to the left fallopian tube of 28 recipients and 47 blastocysts were transferred to the left uterine horn of 26 recipients. (cambridge.org)
Development of the human heart from its first appearance to the stage found in embryos of twenty somites. (ehd.org)
Two human embryos showing early stages of the definitive yolk sac. (ehd.org)
Results: Temperature had an effect on the cleavage rates of developing sea urchin embryos. (orcaeyes.com)

The fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. (umn.edu)
When the ovum is fertilized by a sperm cell (up to 72 hours later) their genetic material combines. (socialbaby.com)

The blastula (from Greek βλαστός (blastos), meaning "sprout") is an early stage of embryonic development in animals. (rulesareforrobots.com)
The early stages of embryonic development are also crucial for ensuring the fitness of the organism. (umn.edu)
The next stage in embryonic development is the formation of the body plan. (umn.edu)
What's the importance of cleavage in embryonic development? (orcaeyes.com)
germ layer, any of three primary cell layers, formed in the earliest stages of embryonic development, consisting of the endoderm (inner layer), the ectoderm (outer layer), and the mesoderm (middle layer). (orcaeyes.com)

In the simplest case, that of small ova destitute of food yolk, the ovum or egg divides into two similar halves or segments (blastomeres), each of these again divides into two, and so on, thus giving rise to a mass of cells (mulberry mass, or morula), all equal and similar, from the growth and development of which the future animal is to be formed. (landak.com)
Basically, the earlier the fertilized ovum divides, the more separate the twins. (pediagenosis.com)

2. An early embryonic form produced by cleavage of a fertilized ovum and consisting of a spherical layer of cells surrounding a fluid-filled cavity. (wordinfo.info)
3. An animal embryo at the stage immediately following the division of the fertilized egg cell, consisting of a ball-shaped layer of cells around a fluid-filled cavity known as a blastocoel. (wordinfo.info)
In the gastrula stage, the segmentation cavity in which the mesoblast is formed lies between the entoblast and ectoblast. (landak.com)

Each cleavage or segmentation yields two BLASTOMERES of about half size of the parent cell. (bvsalud.org)
Segmentation of the ovum , or Egg cleavage (Biol. (landak.com)
Quite frequently, however, the equality and regularity of cleavage is interfered with by the presence of food yolk, from which results unequal segmentation. (landak.com)
a process of cleavage or segmentation, by which the egg undergoes endogenous division with formation of a mass of nearly similar cells, from the growth and differentiation of which the new organism is ultimately formed. (sabda.org)
See Segmentation of the ovum , under Segmentation . (sabda.org)

Both meroblatic and holoblastic cleavages can give rise to the blastula. (differencebetween.net)
In holoblastic eggs, the first cleavage always occurs along the vegetal-animal axis of the egg, the second cleavage is perpendicular to the first. (orcaeyes.com)

The gastrula has three germ layers, that interact in a variety of ways in order to form organs, representing the final stage of embryogenesis - organogenesis. (differencebetween.net)

In every coelomate that sexually reproduces, the process of embryogenesis has four stages: fertilization, cleavage, gastrulation and organogenesis. (differencebetween.net)
The blastula is the first important stage following fertilization, playing a very important role in organism development. (differencebetween.net)
MAIN OUTCOME MEASURES: Number of oocytes retrieved after stimulation, total amount of gonadotropin used, time required for stimulation, number of follicles developing, rate of fertilization, and cleavage in vitro. (arctichealth.org)
Cleavage: rapid, multiple Another effect of fertilization on the plasma membrane of the egg is a several-fold increase in its permeability to various molecules. (grupoelchele.com)
The resulting cell is then called the Implantation may have other related symptoms but implantation bleeding usually has only one symptom January 23rd i started spotting This type of spotting should occur about 7 days after the period Implantation bleeding is a completely normal phenomenon and occurs Fertilization Following ovulation, the ovum with its cumulus oophorus cells are picked up by the fimbria of the fallopian tube. (grupoelchele.com)
Where does cleavage start after fertilization? (orcaeyes.com)
Around 24 hours after fertilization occurs, the first cleavage division occurs. (orcaeyes.com)

Note the smaller polar body between the two blastomeres at the upper margin of the cleavage plane. (ehd.org)
The individual cells that are generated as a result of the cleavage are termed blastomeres and the cleavage phase ends when a hollow sphere of blastomeres called the blastula has formed. (orcaeyes.com)
From here, the spatial arrangement of blastomeres can follow various patterns, due to different planes of cleavage, in various organisms. (orcaeyes.com)

Pregnancy rate based on P 4 level was 17.86% (5/28) and 11.54% (3/26) for early-stage embryo and blastocyst transfer, respectively. (cambridge.org)
Mammals at this stage form a structure called the blastocyst, characterized by an inner cell mass that is distinct from the surrounding blastula, shown in Figure 2b . (umn.edu)
In mammals, the blastula forms the blastocyst in the next stage of development. (umn.edu)
Morula is the stage before BLASTULA in non-mammalian animals or a BLASTOCYST in mammals. (childrensmercy.org)
Dr. Behr developed a culture medium for embryo culture to the blastocyst stage, which improved pregnancy rates, implantation rates and reduced the risks of multiple gestation in IVF. (stanford.edu)

any small hymenopterous insect, which, in the larval stage, lives within the eggs of other insects. (sabda.org)
Meiosis, in contrast, is a specialized kind of cell cycle that reduces the chromosome number by Oogenesis is the process of development of female gametes (also called ova or eggs), that takes place in ovaries. (grupoelchele.com)
Eggs are often in a later stage of cleavage than hookworm species when shed in feces. (cdc.gov)

It is produced by cleavage of a fertilized ovum and consists of a spherical layer of around 128 cells with a large fluid-filled space called the blastocoel in the animal pole of the embryo. (rulesareforrobots.com)
From a spherical to be they polzl, and separated by the ovum of two tail regions of cells. (goldenowlhunt.com)

As the blastula and gastrula are different structures, present at different stages in the embryogenesis process, there are several differences that exist between the two structures. (differencebetween.net)
During the process of embryogenesis, blastula formation is followed by the gastrula, thus both represents a different stage of embryo formation. (differencebetween.net)
The gastrula has more cells present, than in the earlier blastula stage. (differencebetween.net)
A gastrula contains differentiated cells, while the earlier blastula stage only has undifferentiated cells. (differencebetween.net)

There are a number of differences between the two structures, given that each occurs at a different stage of the embryogenesis process. (differencebetween.net)
The placen The stage that the fertilized egg is termed an embryo occurs about 1 day after conception. (grupoelchele.com)

1. An embryo at an early stage of development, consisting of a hollow ball of cells. (wordinfo.info)
After the cleavage has produced over 100 cells, the embryo is called a blastula. (umn.edu)
At this stage of development, illustrated in Figure 3 the inner cell mass consists of embryonic stem cells that will differentiate into the different cell types needed by the organism. (umn.edu)
In humans, lymphocytes are small cells (6 µm in diameter), columnar epithelial cells (10 µm x 20 µm) are medium-size cells, and mature ova (120 to 150 µm) are some of the largest cells. (unboundmedicine.com)

However, it is clear that division of the fertilized ovum at specific early stages of development is responsible for the spectrum of clinical presentations with monozygotic twinning. (pediagenosis.com)
Cleavage prior to development of an inner cell mass will result in two placentas, two sets of membranes and two fetuses, whereas division after the embryonic disc has formed results in conjoined twins. (pediagenosis.com)
Visit the Virtual Human Embryo project at the Endowment for Human Development site to step through an interactive that shows the stages of embryo development, including micrographs and rotating 3-D images. (umn.edu)
For the human embryo, this represents the first two months of intrauterine development preceding the stages of the FETUS. (musc.edu)
Biologic and morphologic development of donated human ova recovered by nonsurgical uterine lavage. (ehd.org)
Two human ova of the pre-villous stage, having a development age of about eight and nine days respectively. (ehd.org)
On the preimplantation stages of the human ovum: A description of four normal and four abnormal specimens ranging from the second to the fifth day of development. (ehd.org)
These creations are the first stages in the development of the nervous system. (socialbaby.com)
Cleavage serves two important functions in early development. (orcaeyes.com)
The miRNA profile of a given cell thus provides a signature of its phenotype and/or stage of development. (justia.com)

This cleavage stage generally covers the period up to 16-cell MORULA . (bvsalud.org)

Three: When it arrives at the spirit-breathing stage, the time of which is subject to controversy, being either forty or 120 days, the fetus acquires greater sanctity, as all scholars agree, and additional legal stipulations apply to it. (islamstickers.uk)
Beginning with Aristotle, quickening divided the developmental stages of embryo and fetus. (asu.edu)

We show that the role for PARP-1 in expression of IL-4-induced genes (e.g. gata-3 ) in splenocytes did not involve effects on STAT6 phosphorylation or its subcellular trafficking, rather, it influenced its occupancy of gata-3 proximal and distal promoters in the early stages of IL-4 stimulation. (biomedcentral.com)

The rapid, multiple rounds of cell division are termed cleavage. (umn.edu)
What is the significance of the early cell division called cleavage? (orcaeyes.com)

the body formed by fusion of the male and female pronucleus in an impregnated ovum. (landak.com)

At the time of sexual intercourse the egg or ovum is a single cell and is just 0.13mm (0.005in) in diameter. (socialbaby.com)

Siamese or conjoined twins are the rarest and arise from cleavage of the differentiating embryonic disc 13-16 days post-conception. (pediagenosis.com)
Two human ova of the pre-villous stage, having an ovulation age of about eleven and twelve days respectively. (ehd.org)

At later stages, PARP-1 was crucial for STAT6 integrity as its inhibition, pharmacologically or by gene knockout, compromised the fate of the transcription factor. (biomedcentral.com)

[ 100 ] Allergens with protease activity may also exert their effect in a protease-independent manner by sensitizing to a non-protease protein like OVA. (medscape.com)
Effect of temperature on sea urchin cleavage. (orcaeyes.com)

Where does embryonic cleavage take place? (orcaeyes.com)

Extremity, and 32 -cell stage front there is also seems, made the foot growths and ctphonantes. (goldenowlhunt.com)

Non-surgical transfer of in vivo fertilised donated ova to five infertile women: report of two pregnancies. (medscape.com)

Cleavage is illustrated in Figure 2a . (umn.edu)

Search Results (3) | Profiles RNS (profiles.ouhsc.edu)

LIEDER Citologia, persone, animali e piante (25 preparati) (astroshop.it)

Carnegie Stage 2-66 - Intact ovum photographed by ordinary microscopy (affiliate.ehd.org)

Ex Ovo Electroporation of DNA Vectors into Pre-gastrulation Avian Embryos | Zenodo (zenodo.org)

Search (core-cms.prod.aop.cambridge.org)

Morula | Profiles RNS (researchers.childrensmercy.org)

Barry Behr, Ph.D., H.C.L.D.'s Profile | Stanford Profiles (profiles.stanford.edu)

Anatomy23

Organisms10

Diseases7

Chemicals and Drugs45

Analytical, Diagnostic and Therapeutic Techniques and Equipment17

Phenomena and Processes47

Information Science4

Health Care2

Chromosome abnormalities in human embryos. (1/708)

Temporal and spatial aspects of fragmentation in early human embryos: possible effects on developmental competence and association with the differential elimination of regulatory proteins from polarized domains. (2/708)

Spatially restricted expression of PlOtp, a Paracentrotus lividus orthopedia-related homeobox gene, is correlated with oral ectodermal patterning and skeletal morphogenesis in late-cleavage sea urchin embryos. (3/708)

The centrosome-attracting body, microtubule system, and posterior egg cytoplasm are involved in positioning of cleavage planes in the ascidian embryo. (4/708)

Identification of two major histocompatibility complex class Ib genes, Q7 and Q9, as the Ped gene in the mouse. (5/708)

Cytoskeletal mechanisms of ooplasmic segregation in annelid eggs. (6/708)

Characterization of novel F-actin envelopes surrounding nuclei during cleavage of a polychaete worm. (7/708)

Comparison of human blastulation rates and total cell number in sequential culture media with and without co-culture. (8/708)

Cleavage Stage, Ovum

Blastomeres

Blastocyst

Ovum

Embryo Culture Techniques

Embryo Transfer

Embryonic Development

Vitrification

Zygote

Preimplantation Diagnosis

Embryo, Nonmammalian

Fertilization in Vitro

Embryo Implantation

Cryopreservation

Polar Bodies

Blastula

Embryo, Mammalian

Oocytes

Urochordata

Ovalbumin

Sea Urchins

Ovum Transport

Pregnancy

Morula

Pregnancy Rate

Fetal Viability

Molecular Sequence Data

Gastrula

Embryonic and Fetal Development

Fertilization

Gene Expression Regulation, Developmental

Germ Layers

Amino Acid Sequence

Xenopus laevis

Embryonic Induction

Xenopus Proteins

DNA Cleavage

Base Sequence

Aneuploidy

Sperm Injections, Intracytoplasmic

Xenopus

Body Patterning

Ectoderm

Octamer Transcription Factor-3

Cell Nucleus

RNA, Messenger

RNA Cleavage

Pregnancy, Multiple

In Situ Hybridization

Zebrafish

Oogenesis

Time Factors

Mesoderm

Zebrafish Proteins

Substrate Specificity

Hydrolysis

Cytoplasm

Endopeptidases

Transcription Factors

Cells, Cultured

Morphogenesis

Peptide Fragments

Protein Processing, Post-Translational

In Situ Hybridization, Fluorescence

Signal Transduction

Transcription, Genetic

Binding Sites

DNA-Binding Proteins

Cell Differentiation

Kinetics

Furin

Caspases

mRNA Cleavage and Polyadenylation Factors

Serine Endopeptidases

Immunoglobulin E

Allergens

Protein Precursors

Cell Line

Recombinant Proteins

DNA