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)

J:122362 Harwood BN, Cross SK, Radford EE, Haac BE, de Vries WN, Members of the WNT signaling pathways are widely expressed in mouse ovaries, oocytes, and cleavage stage embryos. Dev Dyn. 2008;237(4):1099-1111 ...
First, a definition... Klingon Kleavage is a play on cleavage. The women who play Klingons show a lot of clevage with their outfits. My wife and I are T...
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The aim of this study was to evaluate the effects of quarter zona-pellucida (ZP) opening by laser-assisted hatching (QLAH) on the clinical outcomes following transfer of vitrified-warmed blastocysts developed from low-grade cleavage-stage embryos in patients with all high-grade and fair-grade cleavage-stage embryos transferred without achieving pregnancy. Patients were randomized into ...
Mouse morulae from two strains were examined in whole mounts after dissociation of embryos into single cells and were analysed in serial sections by light and electron microscopy. One or two...
Spiral cleavage is a conserved, early developmental mode found in several phyla of Lophotrochozoans resulting in highly diverse adult body plans. While the cleavage pattern has clearly been broadly conserved, it has also undergone many modifications in various taxa. The precise mechanisms of how different adaptations have altered the ancestral spiral cleavage pattern are an important ongoing evolutionary question, and adequately answering this question requires obtaining a broad developmental knowledge of different spirally cleaving taxa. In flatworms (Platyhelminthes), the spiral cleavage program has been lost or severely modified in most taxa. Polyclad flatworms, however, have retained the pattern up to the 32-cell stage. Here we study early embryogenesis of the cotylean polyclad flatworm Maritigrella crozieri to investigate how closely this species follows the canonical spiral cleavage pattern and to discover any potential deviations from it. Using live imaging recordings and 3D reconstructions of
Calcium signaling is known to be associated with cytokinesis; however, the detailed spatio-temporal pattern of calcium dynamics has remained unclear. We have studied changes of intracellular free calcium in cleavage-stage Xenopus embryos using fluorescent calcium indicator dyes, mainly Calcium Green-1. Cleavage formation was followed by calcium transients that localized to cleavage furrows and propagated along the furrows as calcium waves. The calcium transients at the cleavage furrows were observed at each cleavage furrow at least until blastula stage. The velocity of the calcium waves at the first cleavage furrow was approximately 3 microns/s, which was much slower than that associated with fertilization/egg activation. These calcium waves traveled only along the cleavage furrows and not in the direction orthogonal to the furrows. These observations imply that there exists an intracellular calcium-releasing activity specifically associated with cleavage furrows. The calcium waves occurred in ...
Recent lineage tracing studies have allowed us to identify a relationship between the distinct patterns of cleavage divisions that generate the four-cell mouse embryos and the contribution of progeny of four-cell blastomeres to specific regions of the blastocyst (Piotrowska-Nitsche and Zernicka-Goetz, 2005). One of the major patterns of cleavage, in which a meridional second division (an M-division) precedes an oblique/equatorial one (the E-division in ME embryos), is associated with the development of defined polarity to the future embryonic-abembryonic axis. Thus, in this group of embryos, the earlier dividing two-cell blastomere shows a tendency to contribute to the embryonic part of the blastocyst. In such embryos, the later-dividing two-cell blastomere appears to undergo a division that, were it truly equatorial and if cell components were distributed without mixing, would generate one four-cell blastomere with `vegetal and another with `animal components of the egg (Gardner, 2002). Both ...
Stereotypic cleavage patterns play a crucial role in cell fate determination by precisely positioning early embryonic blastomeres. Although misplaced cell divisions can alter blastomere fates and cause embryonic defects, cleavage patterns have been modified several times during animal evolution. However, it remains unclear how evolutionary changes in cleavage impact the specification of blastomere fates. Here, we analyze the transition from spiral cleavage - a stereotypic pattern remarkably conserved in many protostomes - to a biradial cleavage pattern, which occurred during the evolution of bryozoans. Using 3D-live imaging time-lapse microscopy (4D-microscopy), we characterize the cell lineage, MAPK signaling, and the expression of 16 developmental genes in the bryozoan Membranipora membranacea. We found that the molecular identity and the fates of early bryozoan blastomeres are similar to the putative homologous blastomeres in spiral-cleaving embryos. Our work suggests that bryozoans have retained
The fertilised mammalian egg gives rise to seemingly equivalent blastomeres until the fourth cleavage division, when the first indication of lineage specification appears. At this point, certain blastomeres divide symmetrically and others asymmetrically. When do these apparently identical cells diverge and how do these differences arise? To answer this question, Enkui Duan and colleagues performed single-cell transcriptional analysis of human and mouse blastomeres (p. 3468). By studying the mammalian zygote, in which transcription - a known source of heterogeneity during mitosis - is mostly silent, the authors showed that small biases in gene expression arise after the first cleavage division from the unequal distribution of cellular substances between daughter cells, called partitioning errors. These are especially pronounced for transcripts present in small quantities, which are more likely to be asymmetrically distributed. As cleavage divisions progress, the activation of embryonic ...
Sando Rashed 22:24, 23 September 2009 (EST)Cleavage = the repeated division of a fertilised ovum When the zygote nucleus forms the first cleavage forms, this nucleus undergoes a number of mitosis processes, a wrinkle forms down longitudinally passing the poles of the eggs where the sperm enters. This is how the egg is split up into two halves and this process is what forms the 2-cell stage. The process of the second cleavage is the process that allows the 4-cell stage to occur, the wrinkle runs through the poles at right angles instead of running through it longitudinally. The 8 stage cell is formed during the third cleavage it cuts across horizontally but it cuts through closer to the animal poles rather than the vegetal poles. As cleavages continually occur a 16 and 32 cell embryo are formed, and as these cleavages continuously occur the cells closer to the animal poles divide more rapidly and in more numbers compared to the vegetal pole. Eventually with all these cells continuously forming ...
Sando Rashed 22:24, 23 September 2009 (EST)Cleavage = the repeated division of a fertilised ovum When the zygote nucleus forms the first cleavage forms, this nucleus undergoes a number of mitosis processes, a wrinkle forms down longitudinally passing the poles of the eggs where the sperm enters. This is how the egg is split up into two halves and this process is what forms the 2-cell stage. The process of the second cleavage is the process that allows the 4-cell stage to occur, the wrinkle runs through the poles at right angles instead of running through it longitudinally. The 8 stage cell is formed during the third cleavage it cuts across horizontally but it cuts through closer to the animal poles rather than the vegetal poles. As cleavages continually occur a 16 and 32 cell embryo are formed, and as these cleavages continuously occur the cells closer to the animal poles divide more rapidly and in more numbers compared to the vegetal pole. Eventually with all these cells continuously forming ...
Interspecies-SCNT preimplantation embryos derived from human granulosa cells fused with enucleated bovine oocytes. Cleavage embryos (A) and blastocysts (C) derived from SCNT. Parthenogenetically developed cleavage embryos (B) and hatching blastocysts (D) as controls ...
Blastomere cell structure. Coloured scanning electron micrograph of the cell structure of blastomeres in the 4-cell embryo. Blastomeres are the cells formed by divisions of the fertilized egg. Here fractured sections of blastomeres can be seen. The cytoplasm (yellow) contains many dense bodies (green) which are most likely primitive mitochondria. The large hole at centre left is a vacuole opening up onto the cell surface. Small projections (microvilli) can be seen inside the vacuole. Magnification: x4,200 at 5x7cm size. - Stock Image G450/0060
Where did the first cell come from? How did life form from non-life? Abiogeneis is an impossiblity because it requires: Hardware and Software, (Proteins and DNA). Cell must be able to replicate iteslf, Proteins are
TY - JOUR. T1 - Brain and sperm cell surface antigen (NS-4) on preimplantation mouse embryos. AU - Solter, Davor. AU - Camartin, Melitta. PY - 1976/1/1. Y1 - 1976/1/1. N2 - Antiserum prepared in rabbit against 4-day-old mouse cerebellum (anti-NS-4 serum) reacts in the complement-mediated cytotoxicity test with unfertilized and fertilized mouse eggs, cleavage stage embryos, and cells of the trophoblast and inner cell mass of the mouse blastocyst. This activity is specifically removed by absorption of antiserum with adult mouse brain and epididymal sperm but not with adult liver, spleen, kidney, and thymocytes. The antiserum reacts most strongly with cells of the trophoblast and inner cell mass and, in order of decreasing reactivity, with four- to eight-cell stage embryos, zygotes, unfertilized eggs, and two-cell stage embryos.. AB - Antiserum prepared in rabbit against 4-day-old mouse cerebellum (anti-NS-4 serum) reacts in the complement-mediated cytotoxicity test with unfertilized and fertilized ...
There are several differences between the cleavage in mammals and the cleavage in other animals. Mammals have a slow rate of division that is between 12 and 24 hours. These cellular division are asynchronous. Zygotic transcription starts at the two, four, or eight-cell stage. Cleavage is holoblastic and rotational. At the eight-cell stage, the embryo goes through a process called compaction. Most of the blastomeres in this stage become polarized and develop tight junctions with the other blastomeres. This process leads to the development of two different populations of cells: polar cells on the outside and apolar cells on the inside. The outer cells, called the trophoblast cells, secrete fluid on their basal (inner) surface to form a blastocoel cavity through the process of cavitation. These trophoblast cells will eventually give rise to the embryonic contribution to the placenta called the chorion. The inner cells adhere to one side of the cavity to form the inner cell mass (ICM) and will give ...
The role of the TCF family of transcriptional regulators in primary axis formation is addressed by studying the mechanisms of action of XTcf-3 in Xenophus laevis embryos. The early events of primary axis induction involve activation through the WNT signaling pathway. As a result of activation ... read more of the pathway the cytoplasmic level of ß-catenin increases at the future dorsal side of the early cleavage stage embryo. Around the 16-32 cell stage, ß-catenin becomes apparent in the nuclei. The presence of nuclear ß-catenin causes several hours later the activation of specific target genes, like e.g. XSiamois. Since ß-catenin does not contain a DNA binding region, DNA binding proteins must mediate this transactivation. Ectopic expression of ß-catenin causes activation of dorsal genes and results in the induction and differentiation of a secondary axis. (See introduction). Three different homologs of the Tcf/Lef family of transcription factors have been cloned in Xenopus laevis, XTcf-3, ...
We performed in vitro maturation (IVM) and in vitro fertilization (IVF) of the d3 PGCLC- and PGC-derived oocytes and the WT oocytes at 3 weeks (fig. S6B). Despite differences in COC stability and shape, the PGCLC-derived oocytes reached metaphase II (MII), were fertilized, and developed into two-cell embryos with an efficiency comparable to that of oocytes from other sources (Fig. 2B, fig. S6C, and Table 1). Some of the two-cell embryos from the PGCLCs developed further into blastocysts in vitro [19 of 46 (19/46), ~39%] (Fig. 2B). We transferred the two-cell embryos from PGCLCs, as well as those from the other sources, to separate foster mothers. We obtained newborn pups from the two-cell embryos derived from PGCLCs (5/127, ~3.9%), as well as from those derived from E12.5 PGCs (13/75, ~17.3%) and WT 3-week oocytes (7/55, ~12.7%) (Fig. 2C, fig. S7A, and Table 1). All of these offspring grew similarly into adulthood (fig. S7C). The PGCLC-derived offspring bore the BVSC transgenes, a normal ...
Hey guys!!! I had a 3dt on wed and had 1 6 cell and 2 4 cell embryos. wanted to see if anyone got pregnant witha 4 cell! Thanks ...
Blastomere Definition - Blastomere refers to a cell that is created by the early stages of division of a fertilized egg. During in vitro fertilization...
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TY - JOUR. T1 - Different chromatin and energy/redox responses of mouse morulae and blastocysts to slow freezing and vitrification. AU - Somoskoi, Bence. AU - Martino, Nicola A.. AU - Cardone, Rosa A.. AU - Lacalandra, Giovanni M.. AU - DellAquila, Maria E.. AU - Cseh, S.. PY - 2015/3/24. Y1 - 2015/3/24. N2 - Background: The ability to cryopreserve mammalian embryos has become an integral part of assisted reproduction, both in human and veterinary medicine. Despite differences in the size and physiological characteristics of embryos from various species, the embryos have been frozen by either of two procedures: slow freezing or vitrification. The aim of our study was to compare the effect of slow freezing and vitrification to the chromatin structure, energy status and reactive oxygen species production of mouse morulae and blastocysts. Methods: Mouse morulae and blastocysts were randomly allocated into vitrification, slow freezing and control groups. For slow freezing, Dulbecco phosphate ...
The effects of embryo number and incubation volume on the development of mouse embryos were evaluated. The growth rate of two-cell mouse embryos to attached blastocyst stage and the growth rate of blastocysts to early somite stage were assessed after culture in different incubation volumes and embryo densities. Embryos were collected from ICR female mice superovulated with pregnant mare serum gonadotropin and human chorionic gonadotropin and mated by ICR males. In experiment 1, groups of one, five, ten, twenty 2-cell embryos were cultured in 10-, 50-, 500-, 1000-microliter drops of BWW media under mineral oil at 37 degrees C in a humidified atmosphere of 5% CO2 and 95% air. As the incubation volume decreased, significantly ( ...
Lipid rafts enriched in glycosphingolipids (GSLs), cholesterol and signaling molecules play an essential role not only for signal transduction started by ligand binding, but for intracellular events such as organization of actin, intracellular traffic and cell polarity, but their functions in cleavage division of preimplantation embryos are not well known. Here we show that monosialylGb5Cer (MSGb5Cer)-enriched raft domains are involved in development during the cleavage stage of mouse preimplantation embryos. MSGb5Cer preferentially localizes at the interfaces between blastomeres in mouse preimplantation embryos. Live-imaging analysis revealed that MSGb5Cer localizes in cleavage furrows during cytokinesis, and that by accumulating at the interfaces, it thickens them. Depletion of cholesterol from the cell membrane with methyl-beta-cyclodextrin (MbCD) reduced the expression of MSGb5Cer and stopped cleavage. Extensive accumulation of MSGb5Cer at the interfaces by cross-linking with anti-MSGb5Cer Mab (6E2)
Direct knowledge of Ca2+ patterns in vertebrate development is largely restricted to early stages, in which they control fertilization, ooplasmic segregation and cleavage. To explore new roles of Ca2+ in vertebrate development, we injected the Ca2+ indicator aequorin into zebrafish eggs and imaged Ca2+ throughout the first day of development. During early cleavages, a high Ca2+ zone is seen in the cleavage furrows. The high Ca2+ zone during first cleavage spreads as a slow wave (0.5 microm/second) and is preceded by three Ca2+ pulses within the animal pole region of the egg. When Ca2+ concentrations are clamped at the resting level by BAPTA buffer injection into the zygote, all signs of development are blocked. In later development, Ca2+ patterns are associated with cell movements during gastrulation, with neural induction, with brain regionalization, with formation of the somites and neural keel, with otic placode formation, with muscle movements and with formation of the heart. Particularly ...
Transcription factor control of TE/ICM segregation. TE and ICM lineage segregation is controlled by a small group of transcription factors. Specifically, Cdx2 is required for TE development, while the pluripotency markers octamer 3/4 (Oct4), Nanog, and SRY-box containing gene 2 (Sox2) are involved in establishing the ICM fate. In the mouse, Cdx2 is expressed at varying levels in all blastomeres starting at the eight-cell stage, but it becomes restricted to outside, future TE cells, prior to blastocyst formation (Figure 1) (72, 73). This variation in Cdx2 levels between individual blastomeres at the eight-cell stage may be a result of differences in the order and orientation of the cleavage divisions leading up to this stage (71). Embryos missing Cdx2 do form blastocysts initially, but the TE in these embryos loses its epithelial integrity and cannot differentiate further, resulting in death around the time of implantation (74). Oct4, Nanog, and Sox2 have expression patterns that are ...
The egg-to-embryo transition entails transforming a highly differentiated oocyte into totipotent blastomeres, and represents one of the earliest obstacles that...
Enucleated mouse 1-cell embryos arrest development at the 2-cell stage following transplantation of cleavage stage nuclei. Earlier studies employing one-dimensional protein gel electrophoresis failed to reveal obvious differences in gene expression in the manipulated embryos that might account for this block. We report here the results of a quantitative, two-dimensional gel electrophoretic analysis that reveals at least 50 alterations in protein synthesis in the 8--|1-cell nuclear transplant embryos. Approximately half of these alterations involve proteins that normally decrease in synthesis between the 2-cell and 8-cell stages and half involve proteins that are synthesized constitutively between these two stages. These results are the first to reveal significant biochemical alterations that accompany the morphological and cytological differences previously described and indicate that the 8-cell stage nucleus is unable to completely recapitulate the normal progression of changes in protein
1989) Effects of oxygen concentration on the metabolism of [u-14c]glucose by mouse morulae and early blastocysts in vitro. Reproduction, Fertility and Development, 1 (2). pp. 99-106. Wales, R.G., Cuneo, C.L. and Waugh, E.E. ...
Fingerprint Dive into the research topics of A Qualitative Change in the Transcriptome Occurs after the First Cell Cycle and Coincides with Lumen Establishment during MDCKII Cystogenesis. Together they form a unique fingerprint. ...
Other articles where Blastomere is discussed: animal development: Cleavage: …produced during cleavage are called blastomeres. The divisions are mitotic-i.e., each chromosome in the nucleus splits into two daughter chromosomes, so that the two daughter blastomeres retain the diploid number of chromosomes. During cleavage, almost no growth occurs between consecutive divisions, and the total volume of living matter does not…
Strictly defined, the conception of a new individual occurs at the moment when chromosomes from the male and female pronuclei associate to form the mitotic figure of the first cleavage. Despite the...
YAP is a fast scintillation crystal offering great mechanical resistance and stability, with no cleavage planes or hygroscopcity.
More than 90 percent of enucleated one-cell mouse embryos receiving pronuclei from other one-cell embryos successfully develop to the blastocyst stage in vitro. In this investigation, nuclei from successive preimplantation cleavage stages were introduced into enucleated one-cell embryos and the embryos were tested for development in vitro. Although two-cell nuclei supported development to the morula or blastocyst stage, four-cell, eight-cell, and inner cell mass cell nuclei did not. The inability of cell nuclei from these stages to support development reflects rapid loss of totipotency of the transferred nucleus and is not the result of simultaneous transfer of membrane or cytoplasm.
The degradation of maternal proteins is one of the most important events during early development, and it is presumed to be essential for embryonic genome activation (EGA), but the precise mechanism is still not known. It is thought that a large proportion of the degradation of maternal proteins is mediated by the ubiquitin-proteolytic system. In this study we focused on the expression of the Skp1-Cullin1-F-box (SCF) complex, a modular RING-type E3 ubiquitin-ligase, during bovine preimplantation development. The complex consists of three invariable components--Cul1, Skp1, Rbx1 and F-box protein, which determines the substrate specificity. The protein level and mRNA expression of all three invariable members were determined. Cul1 and Skp1 mRNA synthesis was activated at early embryonic stages, at the 4c and early 8c stage, respectively, which suggests that these transcripts are necessary for preparing the embryo for EGA. CUL1 protein level increased from MII to the morula stage, with a ...
P. flavas early cleavage pattern is similar to that of S. kowalevskii. The first and second cleavages from the single cell zygote of P. flava are equal cleavages, are orthogonal to each other and both include the animal and vegetal poles of the embryo. The third cleavage is equal and equatorial so that the embryo has four blastomeres both in the vegetal and the animal pole. The fourth division occurs mainly in blastomeres in the animal pole, which divide transversally as well as equally to make eight blastomeres. The four vegetal blastomeres divide equatorially but unequally and they give rise to four big macromeres and four smaller micromeres. Once this fourth division has occurred, the embryo has reached a 16 cell stage. P. flava has a 16 cell embryo with four vegetal micromeres, eight animal mesomeres and 4 larger macromeres. Further divisions occur until P. flava finishes the blastula stage and goes on to gastrulation. The animal mesomeres of P. flava go on to give rise to the larvas ...
Fornicata are traditionally classified into Diplomonadida, Retortamonadida, Carpediemonas, and Dysnectes. Diplomonadida and Retortamonadida have been regarded as closely related and together they constitute the taxon Eopharyngia (the term refers to the extensively developed cytopharynx of diplomonads and retortamonads). The hypothesis of Eopharyngia was supported by molecular-phylogenetic studies which included sequences of Retortamonas and several diplomonad genera. At first, the studies based on the SSU rRNA gene (Silberman et al. 2002; Kolisko et al. 2005; Keeling and Brugerolle 2006) indicated that diplomonads may not be monophyletic and that Retortamonas may be sister to the Giardiinae diplomonad lineage. However, the analysis based on the hsp90 gene showed that diplomonads are monophyletic and that Retortamonas forms their sister lineage, which was consistent with previous morphology-based hypotheses. Sequence data of the second retortamonads genus, Chilomastix, have been obtained quite ...
Fornicata are traditionally classified into Diplomonadida, Retortamonadida, Carpediemonas, and Dysnectes. Diplomonadida and Retortamonadida have been regarded as closely related and together they constitute the taxon Eopharyngia (the term refers to the extensively developed cytopharynx of diplomonads and retortamonads). The hypothesis of Eopharyngia was supported by molecular-phylogenetic studies which included sequences of Retortamonas and several diplomonad genera. At first, the studies based on the SSU rRNA gene (Silberman et al. 2002; Kolisko et al. 2005; Keeling and Brugerolle 2006) indicated that diplomonads may not be monophyletic and that Retortamonas may be sister to the Giardiinae diplomonad lineage. However, the analysis based on the hsp90 gene showed that diplomonads are monophyletic and that Retortamonas forms their sister lineage, which was consistent with previous morphology-based hypotheses. Sequence data of the second retortamonads genus, Chilomastix, have been obtained quite ...
The top picture shows polar lobe formation during the first cell division. One can see two polar bodies. Polar bodies are the tiny sister cells of the oocyte which are produced during meiosis, contain discarded DNA and mark the animal pole of the embryo (up in the first three pictures). The opposite pole of the embryo is the vegetal pole. The two cells at the animal pole are the first two blastomeres. What looks like a third cell at the vegetal pole is the polar lobe, which at this stage is nearly completely cinched off from either blastomere. Subsequently the polar lobe fuses with one of the blastomeres (second picture from top), so that by the end of the first cell division one of the blastomeres (called CD) is noticeably larger than the AB cell (third picture from top). Polar lobe also forms at the second cell division (not shown). At the four-cell stage blastomere D is the largest, blastomere C is the second largest, while A and B cells are about the same size (bottom picture). The first ...
Esrrb-IRES-Cre knock-in mice express a highly-penentrant Cre recombinase in pre-implantation four-cell stage embryos. These mice are useful for studying ubiquitous gene function in embryos between the zygote or two-cell and blastocyst stages of development, being particularly effective in the cases of genes with essential gametic or zygotic functions.
mNanog and ventx1/2 overexpression cause similar effects in Xenopus embryos.(A) Four-cell stage embryos (NF3) were injected in both dorsal blastomeres, with a 1
TY - JOUR. T1 - Single blastocyst embryo transfer maintains comparable pregnancy rates to double cleavage-stage embryo transfer but results in healthier pregnancy outcomes. AU - Zander-Fox, Deidre. AU - Tremellen, Kelton. AU - Lane, Michelle. PY - 2011/10. Y1 - 2011/10. N2 - Background: The optimal outcome after IVF is a live, healthy, singleton term baby. This can be achieved by transferring a single embryo, but at the possible expense of reducing pregnancy rates. Recent studies suggest that delaying transfer of embryos to the blastocyst stage (day 4/5), rather than the more traditional cleavage stage (day 2-3), allows for better selection of the best embryo, maximising pregnancy rates from a single embryo transfer (SET). The aim of this study was to assess pregnancy outcomes in relation to changing embryo transfer practices. Methods: A retrospective analysis of pregnancy outcomes was made between IVF cycles conducted in 2007 when blastocyst SET became standard practice, with IVF cycles in 2003 ...
STUDY QUESTION: Is the spindle assembly checkpoint (SAC) active during human preimplantation development?. SUMMARY ANSWER: Mitotic spindle disruption during mitosis activates the SAC from at least Day 3 of human preimplantation development, but this does not lead to apoptosis until Day 5.. WHAT IS KNOWN ALREADY: Human preimplantation embryos frequently acquire chromosomal abnormalities, but the mechanisms behind this are poorly understood. It has been speculated that a dysfunctional SAC could be responsible. Although research has shown that the SAC components are present during early human development, functional studies are lacking.. STUDY DESIGN, SIZE, DURATION: In vitro study using human preimplantation embryos in a university research laboratory. We studied a total of 38 Day-3, 38 Day-4, 29 Day-5 and 21 Day-6 human preimplantation embryos, donated for research, during 16 h of incubation.. PARTICIPANT/MATERIALS, SETTING, METHODS: We cultured human preimplantation embryos overnight in a ...
Preimplantation mouse embryos of many stresses become arrested at the 2-cell stage if the osmolarity of culture medium that normally supports development to blastocysts is raised to approximately that of their normal physiological environment in the oviduct. cultured at 310 mOsM progressed through the S phase, and zygotic genome activation markers were expressed. However, most embryos failed to initiate the M phase, as evidenced by intact nuclei with decondensed chromosomes, low M-phase promoting factor activity, and an inactive form of CDK1, although a few blastomeres were arrested in metaphase. Thus, embryos become arrested late in the G2 stage of the second embryonic cell cycle when stressed by physiological osmolarity in the absence of organic osmolytes. was detected using immunocytochemistry as explained previously [22] with minor modifications. All procedures were performed at 37C unless normally noted. Briefly, embryos were incubated in 400 nM MitoTracker (MitoTracker Red CMXRos; ...
AC Stain Alcohol Carmine stain. C Stain Carmine stain. C&FG Stain Carmine & Fast Green. CV Stain Cresyl Violet. FS Stain Fuchsin stain. FS&FG Stain Fuchsin & Fast Green. GS Stain Giemsa. H&E Stain Hematoxylin and Eosin ...
embryo hatching.. Standard IVF protocols include culturing of embryos within the laboratory for three days, followed by transfer of cleavage stage embryos (6 to 8 cells), on Day 3, to the uterine cavity. Following transfer, the embryos must continue to progress to the blastocyst stage, shed the ZP, and embed into the uterine wall. In 1989 Cohen and his co-investigators observed a higher implantation rate in patients undergoing IVF, who had the ZP of their embryos mechanically opened. They therefore hypothesized that artificially creating a gap in the ZP might serve to facilitate embryo hatching and implantation. Microscopic manipulation of the ZP, in order to augment hatching and implantation, subsequently became known as assisted hatching. Prospective randomized clinical studies have been performed in order to evaluate the effectiveness of assisted hatching. Several studies report a significant increase in embryo implantation and clinical pregnancy rates, in select groups of patients whose ...
Embryos from XO female mice begin development with half the activity levels of an enzyme (HPRT) coded for by a gene on the X chromosome, compared with embryos from XX females. Groups of unfertilized eggs and individual embryos at the 8-cell, morula and blastocyst stages were assayed for HPRT activit …
The interval transfer of a frozen-thawed embryo is more successful than a fresh embryo transfer for women undergoing IVF with recurrent implantation failure after cleavage stage embryo biopsy ...
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A preparation and a method of making composite blastocysts (CBs) from aggregates of dissociated cells of non-viable pre-embryos are disclosed. The CB is characterized morphologically by having two distinct tissue types, the inner cell mass (ICM) and the trophectoderm (TE), and a blastocoelic cavity (BC). The ICM is differentially stainable with bisbenzimide and the TE is differentially stainable with propidium iodide. The ICM is pluripotent in that it contains embryonic stem (ES) cells. The TE cells are pluripotent in that they can give rise to all cell types normally derived from TE cells. The primate TE is characterized by the production of chorionic gonadotrophin. The method of making CBs is an aggregation process (AP) comprising inter alia the following steps: 1) dissociation of discarded pre-embryos; 2) isolation of single nucleated cells from dissociated discarded pre-embryos; 3) microsurgical encapsulation of several cells within a host zona pellucida or artificial aggregation with or without a
Both colonial and solitary species are capable of asexual clonal reproduction by budding; species may reproduce sexually and be dioecious, simultaneous, or protandrous hermaphrodites. Eggs either hatch into planktonic larvae, or in some species, complete early development in a brood chamber (located in the atrium), attached by secretions of cement glands to the chambers wall. In some brooding species, nutrition is provided to developing embryos via special placental cells; in others, the egg yolk nourishes the growing larvae. Planktonic larvae may remain free swimming for up to 7 months before settling, while those raised in a brood chamber will settle relatively quickly (within a few days of hatching). (Brusca and Brusca, 2003; Ruppert, et al., 2004; Shanks, 2001). Entoproct embryonic development follows the holoblastic, spiral cleavage pattern typical of protostome organisms, with the mesoderm forming from the 4d mesentoblast. Development continues to a coeloblastula stage, after which, the ...
CN) - A divided Missouri appeals court ruled Tuesday that the frozen embryos of a divorced couple must be treated as marital property, not as children, even though state law defines life as beginning at conception.. A divorce case required a Missouri judge to decide whether two pre-embryos, which were frozen after the couple began the process of in vitro fertilization, should be considered children or marital property.. Jalesia McQueen and Justin Gadberry have two children together, but decided to freeze two pre-embryos before Gadberry began a tour of duty in Iraq in case they wanted to have more.. They dispute whether they discussed what to do with the pre-embryos in case their marriage ended. McQueen filed a petition for dissolution of marriage against Gadberry in October 2013.. At trial, McQueen testified she wanted to implant the embryos in an attempt to potentially have more children with Gadberry.. Gadberry, however, said he does not want to have more children with McQueen, and wants the ...
Sang J. Lee is the author of these articles in the Journal of Visualized Experiments: Loss- and Gain-of-function Approach to Investigate Early Cell Fate Determinants in Preimplantation Mouse Embryos, Procedure for Adaptive Laboratory Evolution of Microorganisms Using a Chemostat
This sounds so familiar. One embryo is a grade one two-cell. Just like the last time at this point. The other one has stopped dividing as of now. But Dr. E said that well continue to keep an eye on it. My fear is that this grade one two-cell embryo may decide not to divide…
Zygote Definition - A zygote is the single-cell that is produced when a sperm fertilizes an egg. It is the first cell in the human body.
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 ...
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 ... The L1 stage usually occurs within four to six days under the optimal conditions of 24-29 °C. The L2 rhabditform sheds its ... Eggs then develop in moist conditions in the feces and continue to develop into the L1 (rhabditiform), and L2 juvenile stages ... "The role of the sheath in resistance of Haemonchus contortus infective stage larvae to proteolytic digestion". Veterinary ...
This mitosis is also known as cleavage. A hollow cavity forms marking the blastocyst stage. (day 1.5-3 of fertilization.) The ... One set of chromosomes came from the nucleus of the ovum and the second set from the nucleus of the sperm. The zygote is male ... In other animals the very early stages of embryogenesis are the same as those in humans. In later stages, development across ... This stage is called a blastocyst. Up to this point there is no growth in the overall size of the embryo, as it is confined ...
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 ...
Cleavage: early stage of embryo development. Cell number increases by cell division. *1. Morula: Solid ball of cells ... Offspring is made by a sperm fertilizing an ovum from the female involves meiosis is very slow method of multiplication. ... The male gamete is the sperm, and the female is ovum. *Spermatogenesis: the process which produces haploid sperm. ... Fertilization: sperm penetrates the cell membrane of ovum. What now exists is a single cell called a zygote. *Internal ...
... constricting the cell membrane to form a cleavage furrow. Continued hydrolysis causes this cleavage furrow to ingress (move ... The stages of cell plate formation include (1) creation of the phragmoplast, an array of microtubules that guides and supports ... for example in oogenesis in animals the ovum takes almost all the cytoplasm and organelles. This leaves very little for the ... Instead of plant cells forming a cleavage furrow such as develops between animal daughter cells, a dividing structure known as ...
The different cells derived from cleavage, up to the blastula stage, are called blastomeres. Depending mostly on the amount of ... In animals, the process involves a sperm fusing with an ovum, which eventually leads to the development of an embryo. Depending ... In holoblastic eggs the first cleavage always occurs along the vegetal-animal axis of the egg, and the second cleavage is ... On the other hand, meroblastic cleavage occurs in animals whose eggs have more yolk (i.e. birds and reptiles). Because cleavage ...
The protein is concentrated in the nuclei of cleavage stage embryos. It cannot be detected in oocytes, indicating temporal ... Alex Lopata (2009). "History of the Egg in Embryology". Journal of Mammalian Ova Research. 26: 2-9. doi:10.1274/jmor.26.2.. ... After cleavage, the dividing cells, or morula, becomes a hollow ball, or blastula, which develops a hole or pore at one end. ... In the stages before fertilization, the anteroposterior axis of the future embryo becomes defined by three systems of molecules ...
... 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 ... Larval stage, ovovivipary in some species.[8]. Amphibians Medium-sized mesolecithal eggs in all species.[7]. Tadpole stage, ... Larval stage in lampreys, direct development in hagfish.[4][5]. Cartilaginous fish Macrolecithal eggs with egg capsule[3]. ...
The space within an ovum or immature ovum is located is the cell-nest Cup uh mukiyam bigil uh. The cumulus-oocyte complex ... 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 the ovary during female gametogenesis. The female ...
Some species eject unfertilized ova into the water, while others keep their ova in brood chambers until they hatch, and some of ... There is no coelom at any stage. In some species the larva is a trochophore which is planktonic and feeds on floating food ... The development of the fertilized egg into a larva follows a typical spiralian pattern: the cells divide by spiral cleavage, ...
Endogenous mutations are more prominent in sperm than in ova.[7] This is because spermatocytes go through a larger number of ... Germline mutations can occur before fertilization and during various stages of zygote development.[3] When the mutation arises ... and this cleavage event initiates cellular repair processes, similar to that of CRISPR/Cas9 DNA editing.[32] ... Errors in maternal ovum also occur, but at a lower rate than in paternal sperm.[6] The types of mutations that occur also tend ...
5. Vesicular follicles in their earliest stage. 6, 7, 8. More advanced follicles. 9. An almost mature follicle. 9'. Follicle ... cholesterol side chain cleavage) system". Arch. Biochem. Biophys. 305 (2): 489-98. doi:10.1006/abbi.1993.1452. PMID 8396893.. ... It is the remains of the ovarian follicle that has released a mature ovum during a previous ovulation.[3] ...
The cleavage of bryozoan eggs is biradial, in other words the early stages are bilaterally symmetrical. It is unknown how the ... Some also release ova into the water, while others capture sperm via their tentacles to fertilize their ova internally. In some ... By the Arenigian stage of the Early Ordovician period, about 480 million years ago, all the modern orders of stenolaemates were ... The sexually reproducing colonies (aclonal) are the result of a larval cupuladriid growing into an adult stage whereas the ...
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 the woman's ovaries and letting sperm fertilise them in a liquid in a laboratory. ... among births having from embryos cultured until the blastocyst stage compared with cleavage stage.[62] ... Dar S, Lazer T, Shah PS, Librach CL (2014). "Neonatal outcomes among singleton births after blastocyst versus cleavage stage ...
An embryo is an early stage of development of a multicellular diploid eukaryotic organism. In general, in organisms that ... In a placental mammal, an ovum is fertilized in a fallopian tube through which it travels into the uterus. An embryo is called ... The blastula stage typically features a fluid-filled cavity, the blastocoel, surrounded by a sphere or sheet of cells, also ... In humans, a pregnancy is generally considered to be in the embryonic stage of development between the fifth and the eleventh ...
It is thought that annelids were originally animals with two separate sexes, which released ova and sperm into the water via ... When their cells divide after the 4-cell stage, descendants of these 4 cells form a spiral pattern. In these phyla the "fates" ... "spiral determinate cleavage".[67] ... are the same and can be predicted from a very early stage.[66] ... Most polychaetes whose reproduction has been studied lack permanent gonads, and it is uncertain how they produce ova and sperm ...
All bony fish, some sharks and rays have yolk sacs at some stage of development, with all oviparous fishes retaining the sac ... The yolk mass, together with the egg cell or ovum properly (after fertilization, the embryo) are enclosed by the vitelline ... After the fertilization, the cleavage of the embryo leads to the formation of the germinal disc. ...
The oral-aboral axis is specified early in cleavage, and the left-right axis appears at the late gastrula stage.[23] ... The transparency of the urchin's eggs enabled them to be used to observe that sperm cells actually fertilize ova.[55] They ... During cleavage, mesoderm and small micromeres are specified. At the end of gastrulation, cells of these two types form ... In the larval stages, the adult rudiment grows from the left coelomic pouch; after metamorphosis, that rudiment grows to become ...
The sperm and ovum unite through fertilisation, creating a zygote that (over the course of 8-9 days) implants in the uterine ... Rheotaxis, thermotaixs and chemotaxis are known mechanisms in guiding sperm towards the egg during the final stage of sperm ... In 1784, Spallanzani established the need of interaction between the female's ovum and male's sperm to form a zygote in frogs.[ ... In 2004, Japanese researchers led by Tomohiro Kono succeeded after 457 attempts to merge the ova of two mice by blocking ...
... if only at certain life stages. In most animals, embryos pass through a blastula stage,[11] which is a characteristic exclusive ... Deuterostome embryos undergo radial cleavage during cell division, while protostomes undergo spiral cleavage.[106] ... non-motile gametes are ova.[21] These fuse to form zygotes, which develop via multiple successive mitoses and differentiation ... A newt lung cell stained with fluorescent dyes undergoing the early anaphase stage of mitosis ...
The blastula is a stage in embryonic development that is unique to most animals,[14] allowing cells to be differentiated into ... The Spiralia are a large group of protostomes that develop by spiral cleavage in the early embryo.[135] The Spiralia's ... non-motile gametes are ova.[22] These fuse to form zygotes,[23] which develop via mitosis into a hollow sphere, called a ... Early in development, deuterostome embryos undergo radial cleavage during cell division, while many protostomes (the Spiralia) ...
The protein is concentrated in the nuclei of cleavage stage embryos. It cannot be detected in oocytes, indicating temporal ... Alex Lopata (2009). "History of the Egg in Embryology". Journal of Mammalian Ova Research. 26: 2-9. doi:10.1274/jmor.26.2.. ... After cleavage, the dividing cells, or morula, becomes a hollow ball, or blastula, which develops a hole or pore at one end. ... In the stages before fertilization, the anteroposterior axis of the future embryo becomes defined by three systems of molecules ...
It is thought that annelids were originally animals with two separate sexes, which released ova and sperm into the water via ... When their cells divide after the 4-cell stage, descendants of these 4 cells form a spiral pattern. In these phyla the "fates" ... "spiral determinate cleavage".[67] ... are the same and can be predicted from a very early stage.[66] ... Most polychaetes whose reproduction has been studied lack permanent gonads, and it is uncertain how they produce ova and sperm ...
The blastula is a stage in embryonic development that is unique to most animals,[14] allowing cells to be differentiated into ... The Spiralia are a large group of protostomes that develop by spiral cleavage in the early embryo.[135] The Spiralia's ... non-motile gametes are ova.[22] These fuse to form zygotes,[23] which develop via mitosis into a hollow sphere, called a ... Early in development, deuterostome embryos undergo radial cleavage during cell division, while many protostomes (the Spiralia) ...
Development of the human embryoFirst stages of human development. (A-D) Cleavage of ovum. (E-F) Blastocyst development.. ... This type of cleavage is known as total, equal cleavage. The sticky blastomeres adhere, and the cluster is still retained for a ... which in humans encompasses three distinct stages: (1) the pre-embryonic stage, the first two weeks of development, which is a ... Such early stages in definite lines of differentiation of cells are often designated by the suffix -blast, as in myoblast and ...
Ovum cleavage stage‎ (7 F). S. *. ► Cell division on stamps‎ (2 F) ...
Cleavage Stage, Ovum * Culture Techniques * Fluorescent Antibody Technique * Interphase * Microtubules / ultrastructure* * ... Fourth cleavage of sea urchin blastomeres: microtubule patterns and myosin localization in equal and unequal cell divisions Dev ... and that contractile ring myosin concentrates and disperses in precise coincidence with the beginning and end of cleavage ...
... is specified by a stable positional system set up by a cytoplasmic rotation in the zygote that occurs before first cleavage. ... Cleavage Stage, Ovum / drug effects * Embryo, Nonmammalian / drug effects* * Embryonic Development / drug effects* ... is specified by a stable positional system set up by a cytoplasmic rotation in the zygote that occurs before first cleavage. ...
Cleavage Stage, Ovum. Embryonic Stem Cells / cytology*. Female. Homeodomain Proteins / analysis. Immunohistochemistry. Mice. ... of BTMs from two-cell stage and 20% from four-cell stage. Four ES cell lines (5.6%; 4/72) were established ater culture of ...
Cleavage Stage, Ovum / physiology*. Female. Fertilization in Vitro. Follicle Stimulating Hormone / pharmacology. Humans. ... 10459517 - Fertilization and development of a blastocyst-stage embryo after selective intracytopla.... 12923147 - Metaphase ii ...
This mitosis is also known as cleavage. A hollow cavity forms marking the blastocyst stage. (day 1.5-3 of fertilization.) The ... One set of chromosomes came from the nucleus of the ovum and the second set from the nucleus of the sperm. The zygote is male ... In other animals the very early stages of embryogenesis are the same as those in humans. In later stages, development across ... This stage is called a blastocyst. Up to this point there is no growth in the overall size of the embryo, as it is confined ...
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 ...
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 ... The L1 stage usually occurs within four to six days under the optimal conditions of 24-29 °C. The L2 rhabditform sheds its ... Eggs then develop in moist conditions in the feces and continue to develop into the L1 (rhabditiform), and L2 juvenile stages ... "The role of the sheath in resistance of Haemonchus contortus infective stage larvae to proteolytic digestion". Veterinary ...
Embryonic LPA production into culture medium was also detected at both stages of development. Supplementation of culture medium ... K. Kunikata, S. Yamano, A. Tokumura, and T. Aono, "Effect of lysophosphatidic acid on the ovum transport in mouse oviducts," ... Late cleavage stage embryos showed significantly higher mRNA abundance of all LPARs than blastocyst stage embryos. Expression ... Late Cleavage and Blastocyst Stage Embryos Transcribed and Expressed Genes Coding for LPA Receptors (LPAR1-4). As shown in ...
This mitosis is also known as cleavage. A hollow cavity forms marking the blastocyst stage. (day 1.5-3 of fert.[2]) ... Fertilization of the ovum (egg cell) usually takes place in the Fallopian tube. Many sperm must cooperate to penetrate the ... This stage is called a blastocyst. Up to this point there is no growth in the overall size of the embryo, so each division ... Fertilization of the ovum to form a zygote. (day 1 of fert.[2]) ... thick protective shell-like barrier that surrounds the ovum. ...
Blastomeres are produced through cleavage, a type of cell division, of the ovum after fertilisation. Many blastomeres make up a ... hollow sphere of cells known as the blastula (seen here). Here, the cell at centre is in the anaphase stage of mitotic division ... Light micrograph of a section through a fish embryo during the early stages development. The cells here are known as ... Blastomeres are produced through cleavage, a type of cell division, of the ovum after fertilisation. Many blastomeres make up a ...
The newly released ovum. Center. Embryo at about the beginning of the 4-cell stage; about 4 hours old. Cleavage is incomplete ... The embryo is at the 16-celled stage; about 8 hours old. Bottom: This embryo is at the blastula stage, about 12 hours old. ... The 8-celled stage is about the same diameter as a newly spawned egg; about 7 hours after fertilization. Center. ... Anyway I am still in the very early stages of this thing, and I am trying to find some more background information about Pyrams ...
The newly released ovum. Center. Embryo at about the beginning of the 4-cell stage; about 4 hours old. Cleavage is incomplete ... The embryo is at the 16-celled stage; about 8 hours old. Bottom: This embryo is at the blastula stage, about 12 hours old. ... The 8-celled stage is about the same diameter as a newly spawned egg; about 7 hours after fertilization. Center. ... Gastrula stages; individual cells no longer visible. Left. Early gastrula, irregularly shaped, about 24 hours old. Center. ...
... of in vitro matured and fertilized oocytes attaining cleavage and developing to the 8-cell embryo stage. The maturation rates ... In vitro Embryo Production and Ovum Pick Up. The in vitro production (IVP) of embryos based on the combination of in vitro ... The ability of oocytes at germinal vesicle (GV)-stage and M2 stage to survive, mature and fertilize after a freeze-warm cycle ... The IVF system with high rate of cleavage (77%) and development to blastocyst stage (33-51%) was set up by Parpnais group ...
a solid, spherical mass of cells resulting from the cleavage of the fertilized ovum in the early stages of embryonic ... a solid ball of cells resulting from cleavage of a fertilized ovum. It is formed of a mass of BLASTOMERES which subsequently ... a solid mass of cells (blastomeres) resembling a mulberry, formed by cleavage of a zygote (fertilized ovum). ... The spherical embryonic mass of blastomeres formed before the blastula and resulting from cleavage of the fertilized ovum. ...
... or ovum) with a male gamete (sperm). In the embryonic development of humans and other ... the zygote stage is brief and is followed by cleavage, when the single cell becomes subdivided into smaller cells. ... Zygote, fertilized egg cell that results from the union of a female gamete (egg, or ovum) with a male gamete (sperm). In the ... During cleavage the relatively enormous zygote directly subdivides into many smaller cells of conventional size through the ...
What is isolecithal ovum? Meaning of isolecithal ovum medical term. What does isolecithal ovum mean? ... Looking for online definition of isolecithal ovum in the Medical Dictionary? isolecithal ovum explanation free. ... The term is sometimes applied to any stage of the fertilized germ cell during cleavage and even until hatching or birth of the ... meroblastic ovum one that undergoes partial cleavage.. primitive ovum (primordial ovum) any oocyte very early in its ...
Sperm and egg cells called gametes . Product of egg + sperm = fertilized egg = zygote . Embryo = early stages of an organisms ... Cleavage starts 24 hours after fertilization. By 6th or 7th day, embryo at 100 cell stage reaches uterus. 100 cell stage= ... Sperm passes through jelly coat of ova by releasing acrosomal enzymes. • Proteins on sperm bind to ova receptor proteins; ... At what developmental stage does implantation occur? • The embryo at the 100 cell stage is called the ___________ • What are ...
blastosphere, blastula - early stage of an embryo produced by cleavage of an ovum; a liquid-filled sphere whose wall is ... The cleavage, blastocyst, and hatching rates were detected on days 3, 6, and 7, respectively (Day 0 defined as the day of ... However at the ARU, blastocyst culture enables embryos to be "grown" in a lab to the blastocyst stage of development (day five ... As for the blastocyst, the term describes an embryos stage of development, not a different thing than an embryo.. Waddya know ...
Maturation divisions in ova of Ascaris megalocephala, different stages, ironhematoxylin stained. Cleavage stages in ova of ... gastrula stages. Frog embryology (Rana spec.), sec. trough the blastula stage showing the blastocoel. Frog embryology (Rana ... Human chromosomes, spread in the stage of metaphase, for counting chromosomes. Meiotic and mitotic stages in sec. of crayfish ... through young larva in the tail bud stage, with. primordia of organs. Ecology and Environment. Leaf (needle) of fir (Abies), ...
... morphology turned Brachets attention to the earliest stages of development-the first cleavage of the fertilized ovum, the ... For example, there is a well-known stage when the embryo has the form of a hollow ball so deeply indented at one point that the ... Brachet also devoted much time to the study of ova, chiefly of the frog, into which, by experimental treatment, he caused more ... For example, by pricking one of the two cells into which the fertilized ovum first divides, or similarly damaging one or ...
blastosphere, blastula - early stage of an embryo produced by cleavage of an ovum; a liquid-filled sphere whose wall is ... 2. (also adjective) (of) the beginning stage of anything. The project is still at the embryo stage. in wording في طَوْر الجَنين ... 1. (Zoology) an animal in the early stages of development following cleavage of the zygote and ending at birth or hatching ... 1. an animal in the early stages of development in the womb or egg; in humans, the stage approximately from attachment of the ...
Growth of the Ovarian Ovum, Maturation, Fertilisation and Early Cleavage. Transactions of the Zoological Society of London, 24 ...
Ag uptake and binding (AF488-ova) were evident at all reproductive stages; however, lactation and involution (day 2) dendritic ... signal and for Ag processing by DQ-OVA signal, which is produced upon Ag cleavage in the lysosome because of reduced pH. ... D) Abundance of RORγT+ (Foxp3−) and (E) Foxp3+ (RORγT−) CD4+ T cells by reproductive stage. (F) Representative flow plots of ... OVA-specific (DO11.10 TCR transgenic) CD4+ T cells were activated in vitro with anti-CD3 and anti-CD28 in the presence of TGF- ...
The embryos were classified as unfertilised ova (no cleavage), degenerate embryos (embryos at 8-cell stage and earlier stage) ... The total number of recovered structures (unfertilised ova and embryos) was evaluated microscopically for the stage of ... No recovery of unfertilised ova was recorded in the young does and the fertilisation rate and mean number of unfertilised ova ... Survival of fertilized ova from ewe lambs and adult ewes in the uteri of ewe lambs. Anim. Reprod. Sci. 8, 235-240. [ Links ]. ...
... cell stage ova from mated females were chosen as the starting point from which to follow these parameters through cleavage and ... Mammalian ova have not been studied as thoroughly as the eggs of lower vertebrates. Increasing interest in the physiology and ... Up to now there have been no direct chemical analyses of mammalian ova published. Reported here are the dry mass and protein ... Peter Baillie-Johnson was working on the generation of elongating gastruloids to mimic the first stages of axial elongation in ...
Embryogenesis starts with the fertilization of the egg cell (ovum) by a sperm cell, (spermatozoon). Once fertilized, the ovum ... The embryonic stage begins on the 15th day after conception and continues until about the 8th week, or until the embryo is 1.2 ... The zygote undergoes mitotic divisions with no significant growth (a process known as cleavage) and cellular differentiation, ... Embryogenesis starts with the fertilization of the egg cell (ovum) by a sperm cell, (spermatozoon). Once fertilized, the ovum ...
Cleavage: early stage of embryo development. Cell number increases by cell division. *1. Morula: Solid ball of cells ... Offspring is made by a sperm fertilizing an ovum from the female involves meiosis is very slow method of multiplication. ... The male gamete is the sperm, and the female is ovum. *Spermatogenesis: the process which produces haploid sperm. ... Fertilization: sperm penetrates the cell membrane of ovum. What now exists is a single cell called a zygote. *Internal ...
  • The zygote undergoes mitotic divisions with no significant growth (a process known as cleavage) and cellular differentiation, leading to development of a multicellular embryo after passing through an organizational checkpoint during mid-embryogenesis. (wikipedia.org)
  • In animals, the process involves a sperm fusing with an ovum, which eventually leads to the development of an embryo. (wikipedia.org)
  • Light micrograph of a section through a fish embryo during the early stages development. (sciencephoto.com)
  • An early stage in the development of the embryo at which it consists of a solid spherical ball of apparently identical cells. (thefreedictionary.com)
  • 9. What stage of embryo development is the beginning of differentiation. (slideserve.com)
  • Data for the Early Embryo Viability Assessment (Eeva(TM)) Test demonstrate that transfer of embryos at Day 3 resulted in comparable clinical outcomes to blastocyst stage (Day 5 of development after fertilisation) transfer when the Eeva(TM) Test is used in combination with review of embryo shape and structure (morphology) to improve embryo assessment. (thefreedictionary.com)
  • Using this new technology, the embryologists can now provide a more stable environment to allow greater numbers of embryos to develop to [euro]ve days old when the embryo reaches what is called the blastocyst stage. (thefreedictionary.com)
  • As for the blastocyst , the term describes an embryo's stage of development, not a different thing than an embryo. (thefreedictionary.com)
  • For example, there is a well-known stage when the embryo has the form of a hollow ball so deeply indented at one point that the indented region coats the inside of the outer wall and the embryo is thus a two-layer sphere with an opening to the outside, the blastopore. (encyclopedia.com)
  • Another and even more recondite set of problems includes such questions as the extent to which embryonic structures are laid down in the undivided ovum, and the relation of the first planes of its cleavage to the axis of symmetry of the embryo. (encyclopedia.com)
  • Peter Baillie-Johnson was working on the generation of elongating gastruloids to mimic the first stages of axial elongation in the mouse embryo, but was limited by aggregates adhering to the surface of culture plates. (biologists.org)
  • Cleavage: early stage of embryo development. (wikipedia.org)
  • In embryology: An embryo of 1 for the Metazoa, within the stage by which it contains a sac formed of one layer of cells. (azdictionary.com)
  • Typical somatic cells in animals are 5-10 µm in diameter, but ova can be a millimeter or more in diameter, and individual blastomeres (the cells in the cleavage stage embryo) can be several hundred µm across. (freethoughtblogs.com)
  • Prefaced by younger stages of the chick embryo. (edu.au)
  • In embryology , cleavage is the division of cells in the early embryo . (academic.ru)
  • Each cell produced by early embryonic cleavage does not have the capacity to develop into a complete embryo . (academic.ru)
  • p. 36-37) [We can use the cleavage discussion to show that now the embryo is operating on its own and developing. (princeton.edu)
  • The newly formed embryo undergoes a series of cells divisions called cleavage as it travels down the oviduct toward the uterus. (princeton.edu)
  • A]nimal biologists use the term embryo to describe the single cell stage, the two-cell stage, and all subsequent stages up until a time when recognizable humanlike limbs and facial features begin to appear between six to eight weeks after fertilization. (princeton.edu)
  • We describe a series of stages for development of the embryo of the zebrafish, Danio (Brachydanio) rerio. (nih.gov)
  • The stages, and their names, are based on morphological features, generally readily identified by examination of the live embryo with the dissecting stereomicroscope. (nih.gov)
  • Women with a singleton live birth following a fresh or frozen autologous embryo transfer of a PGT blastocyst, non-PGT blastocyst, or non-PGT cleavage stage embryo were included. (cdc.gov)
  • In its widest definition, the embryo is the young from the moment of fertilization fertilization, in biology, process in the reproduction of both plants and animals, involving the union of two unlike sex cells (gametes), the sperm and the ovum, followed by the joining of their nuclei. (thefreedictionary.com)
  • We compared the rates of no transferrable embryo cycles, fertilization, cleavage, normal fertilization, abnormal fertilization, high-quality embryo and transferrable embryo between the two groups. (bvsalud.org)
  • To explore the developmental potential of embryos at different developmental days and provide evidence for blastocyst culture of non-top quality cleavage stage embryos in frozen-thawed embryo transfer (FET) cycles. (bvsalud.org)
  • According to the embryo freezing time, the patients were divided into day 5 (D5) blastocyst group (n=87), day 6 (D6) blastocyst group (n=111) and day 3 cleavage-stage embryo (D3) group (n=489) with hormone replacement cycles or natural cycles for endometrial preparation. (bvsalud.org)
  • The process of fertilization is now complete and the fertilized ovum undergoes its first cleavage to produce a two celled embryo . (blogspot.com)
  • You can also perform the biopsy from the one blastomere of embryo cleavage stage or use 5‐10 trophoectoderm cells blastocyst. (elsevier.es)
  • this stage covers late steps of the embryogenesis with a fully formed embryo still developing before birth or egg hatching. (githubusercontent.com)
  • the study of growth and development of the "embryo" and "fetus" from "fertilization" of the "ovum" until birth. (richardsonthebrain.com)
  • Development continues unti maturity Fertilization Cleavage Gastrulation External Development of frog eggs Internal Development of a Dog Embryo Yolk Umbillicus/Placenta The evolution of the amniotic egg was a major adaptation that allowed reptiles (and subsequently birds & mammals) to spend their entire lifecycle on land. (prezi.com)
  • By manipulating frog embryos at early stages of development, polarity is disturbed Removal of a specific region (the 'gray crescent'), leads to an embryo lacking dorsal structures Transplantation of a specific region (dorsal lip) leads to a duplication of the embryo in opposite polarity. (prezi.com)
  • Normal 2-cell stage embryo growth and offspring from these eggs has been confirmed using in vitro fertilization and embryo transfer. (healthcanal.com)
  • By allowing a large number of ovulation ovum from a small number of female mice, it makes it easier to perform IVF and embryo transfers. (healthcanal.com)
  • Embryo is the first stage of life. (shalby.org)
  • 2-3 days after ovum pick up, 2-3 of the best embryos are selected for Embryo transfer. (shalby.org)
  • 228 BIOLOGICAL PHYSICS OF THE DEVELOPING EMBRYO early cleavage stages leads to a several-thousand-fold ampli ¬ cation of the number of copies of the genes specifying ribosomal RNA in the oocyte nucleus during oogenesis (Thiebaud, 1979). (nanobukva.ru)
  • It is the stage where the embryo has massive rearrangements to form multi-layers of cells. (knowswhy.com)
  • Blastula is basically referred to as the pre-embryo stage and the gastrula as the mature stage. (knowswhy.com)
  • The embryos of many animals appear similar to one another in the earliest stages of development and progress into their specialized forms in later stages. (britannica.com)
  • Multinucleation and cleavage of embryos derived from in vitro-matured oocytes. (biomedsearch.com)
  • Holoblastic cleavage occurs in animals with little yolk in their eggs, such as humans and other mammals who receive nourishment as embryos from the mother, via the placenta or milk, such as might be secreted from a marsupium. (wikipedia.org)
  • In Born's laboratory he also observed newly introduced procedures of experimental embryology, by which Born and other embryologists were beginning to analyze embryonic development by excising parts of early embryos (chiefly of frogs and salamanders), transplanting limb buds, and producing local damage in the ovum and in early embryos. (encyclopedia.com)
  • The fertilisation rate, the mean number of unfertilised ova and degenerate embryos recorded did not differ between the young and adult multiparous does. (scielo.org.za)
  • The individual cells were uniform in size, as seen in many cleavage stage embryos, and contained organelles arranged in a consistent pattern . (freethoughtblogs.com)
  • Another unusual bias in the sample is that all of the embryos exhibit that regularity of division that produces equal-sized blastomeres-yet many invertebrate embryos have early asymmetric cleavages that produce recognizable, stereotyped distributions of cells. (freethoughtblogs.com)
  • who developed the biogenetic law biogenetic law, in biology, a law stating that the earlier stages of embryos of species advanced in the evolutionary process, such as humans, resemble the embryos of ancestral species, such as fish. (thefreedictionary.com)
  • Minami N, Aizawa A, Ihara R, Miyamoto M, Ohashi A, Imai H. Oogenesin is a novel mouse protein expressed in oocytes and early cleavage-stage embryos. (labome.org)
  • He observed that in the normal development of Amphioxus, all three main types of symmetry, or cleavage patterns observed in embryos, could be found. (asu.edu)
  • Enucleated mouse 1-cell embryos arrest development at the 2-cell stage following transplantation of cleavage stage nuclei. (cshl.edu)
  • Embryos in many species often appear similar to one another in early developmental stages. (wikipedia.org)
  • The inseminated eggs are periodically observed under the microscope to check for fertilization and cleavage (Cell Division) about 16-17 hours after insemination, the egg and sperm combinations develop into embryos. (shalby.org)
  • In this species, the body plan is specified by a stable positional system set up by a cytoplasmic rotation in the zygote that occurs before first cleavage. (nih.gov)
  • In contrast, the mitochondrial genetic information of the zygote comes entirely from the mother via the ovum. (wikipedia.org)
  • Once fertilized, the ovum becomes a single diploid cell known as a zygote. (wikipedia.org)
  • Cell division with no significant growth, producing a cluster of cells that is the same size as the original zygote, is called cleavage. (wikipedia.org)
  • Because cleavage is impeded in the vegetal pole, there is an uneven distribution and size of cells, being more numerous and smaller at the animal pole of the zygote. (wikipedia.org)
  • Zygote , fertilized egg cell that results from the union of a female gamete (egg, or ovum) with a male gamete ( sperm ). (britannica.com)
  • In the embryonic development of humans and other animals, the zygote stage is brief and is followed by cleavage , when the single cell becomes subdivided into smaller cells. (britannica.com)
  • The zygote represents the first stage in the development of a genetically unique organism. (britannica.com)
  • In fact, the genes of the new zygote are not activated to produce proteins until several cell divisions into cleavage. (britannica.com)
  • During cleavage the relatively enormous zygote directly subdivides into many smaller cells of conventional size through the process of mitosis (ordinary cell proliferation by division). (britannica.com)
  • The solid mass of blastomeres resulting from the early cleavage divisions of the zygote. (thefreedictionary.com)
  • 1. the solid mass of blastomeres formed by cleavage of a zygote. (thefreedictionary.com)
  • It represents an intermediate stage between the zygote and the blastocyst and consists of blastomeres that are uniform in size, shape, and physiological capabilities. (thefreedictionary.com)
  • Once fertilized, the ovum is referred to as a zygote, a single diploid cell. (wn.com)
  • The first cleavage results in bisection of the zygote into left and right halves. (academic.ru)
  • cleavage-zygote-fertilization-morula-blastula-gastrula. (johnnydeppnetwork.com)
  • First sentence of the Chapter: "Human development begins at fertilization when a male gamete or sperm (spermatozoon) unites with a female gamete or oocyte (ovum) to form a single cell - a zygote . (princeton.edu)
  • Cleavage consists of repeated mitotic divisions of the zygote , resulting in a rapid increase in the number of cells. (princeton.edu)
  • The cleavage divisions subdivide the zygote first into two cells, then into four, then into eight, and so on. (princeton.edu)
  • Fertilization occurs with the penetration of the spermatozoon in the ovum, and the consequent formation of the zygote. (babyhelp411.com)
  • Embryonic development (beginning with the first mitotic division of the zygote) can be divided into three consecutive stages: segmentation , gastrulation and organogenesis. (babyhelp411.com)
  • The cleavage, or cleavage stage is the stage that ranges from the first division of the zygote to blastocyst formation. (babyhelp411.com)
  • Among other stages such organogenesis, cleavage and the gastrulation, fertilization is the first stage in which a diploid zygote (fertilized ovum) is formed following the fusion of female and male gametes. (knowswhy.com)
  • Humanity begins at the moment of conception, when a sperm and an egg come together to form a zygote, which, according to Encyclopedia Britannica, is "a fertilized egg cell that results from the union of a female gamete (egg, or ovum) with a male gamete (sperm). (abortionexploitswomen.com)
  • Despite all the scientific evidence confirming what we know to be true about life in the womb, abortion supporters continue to devalue the preborn-from the zygote stage through the first few months of fetal development and, in many cases, even until the human is born. (abortionexploitswomen.com)
  • After the 7th cleavage has produced 128 cells, the morula becomes a blastula. (wikipedia.org)
  • in forms with considerable yolk, the configuration of the morula stage is greatly modified. (thefreedictionary.com)
  • El cuadro febril de la Ehrlichiosis es similar a la producida por la Fiebre Manchada de las montanas Rocosas, con la excepcion de que en la Ehrlichiosis se encuentra la morula yen esta ultima esta ausente y que la serologia para R. (thefreedictionary.com)
  • That phase in the growth of the ovum in which the exterior cells regarding the morula be defined and form the blastoderm. (azdictionary.com)
  • That stage in growth of the ovum where the outer cells of this morula be more defined and form the blastoderm. (azdictionary.com)
  • The different cells derived from cleavage are called blastomeres and form a compact mass called the morula . (academic.ru)
  • After cleavage , the dividing cells, or morula , becomes a hollow ball, or blastula , which develops a hole or pore at one end. (wikipedia.org)
  • Depending mostly on the amount of yolk in the egg, the cleavage can be holoblastic (total) or meroblastic (partial). (wikipedia.org)
  • Meroblastic cleavage occurs in animals whose eggs have more yolk (i.e. birds and reptiles). (wikipedia.org)
  • The human ovum consists of protoplasm that contains some yolk, enclosed by a cell wall consisting of two layers, an outer one ( zona pellucida ) and an inner, thin one ( vitelline membrane ). (thefreedictionary.com)
  • centrolecithal ovum one with the yolk concentrated at the center of the egg, surrounded by a peripheral shell of cytoplasm, and with an island of cytoplasm surrounding the nucleus, such as that of an arthropod. (thefreedictionary.com)
  • isolecithal ovum one with a small amount of yolk evenly distributed throughout the cytoplasm. (thefreedictionary.com)
  • telolecithal ovum one with a comparatively large amount of yolk massed at one pole, such as that of a reptile or bird. (thefreedictionary.com)
  • an ovum in which the yolk is evenly distributed throughout the cytoplasm. (thefreedictionary.com)
  • An ovum with a small yolk portion that is distributed throughout the protoplasm. (thefreedictionary.com)
  • An ovum having a large central food yolk, as in a bird's egg. (thefreedictionary.com)
  • An ovum in which only the protoplasmic region undergoes cleavage, characteristic in ova containing a large amount of yolk. (thefreedictionary.com)
  • An ovum in which the yolk is fairly abundant and tends to concentrate in one hemisphere. (thefreedictionary.com)
  • In the absence of a large concentration of yolk, four major cleavage types can be observed in isolecithal cells (cells with a small even distribution of yolk) or in mesolecithal cells (moderate amount of yolk in a gradient) - bilateral holoblastic, radial holoblastic, rotational holoblastic, and spiral holoblastic, cleavage. (academic.ru)
  • Mammals display rotational cleavage, and an isolecithal distribution of yolk (sparsely and evenly distributed). (academic.ru)
  • of an ovum, having little or no yolk. (absp.org.uk)
  • the protoplasmic part of an ovum, distinguished from the yolk. (absp.org.uk)
  • The yolk prevents the division from taking place through the egg, resulting in meroblastic cleavage during the many cleavage divisions. (enacademic.com)
  • blastoderm - In many eggs with a large amount of yolk, cell division (cleavage) is restricted to a superficial layer of the fertilized egg (meroblastic cleavage). (enacademic.com)
  • The amphibian egg represents the final attempt on the part of nature to produce a large yolk-laden egg in which cleavage involves the entire ovum. (uni.edu)
  • As a result of this method of cleavage all the embryonic tissues, during the early stages of development, contain more or less yolk. (uni.edu)
  • The different cells derived from cleavage, up to the blastula stage, are called blastomeres. (wikipedia.org)
  • The egg is about 70-85 μm long by 44 μm wide, and the early stages of cleavage contain between 16 and 32 cells. (wikipedia.org)
  • a solid, spherical mass of cells resulting from the cleavage of the fertilized ovum in the early stages of embryonic development. (thefreedictionary.com)
  • An early stage of embryonic development characterised by a solid ball of about 32 primitive cells. (thefreedictionary.com)
  • a solid ball of cells resulting from cleavage of a fertilized ovum. (thefreedictionary.com)
  • Cleavage partitions cells into developmental regions. (slideserve.com)
  • Two major advances in stem cell research occurring in 2013 and 2014 pave the way for eventual mitochondrial replacement therapy: (1) successful cloning of a human to the blastocyst stage of development, and (2) transformation of specialized mouse, somatic cells into totipotent cells. (thefreedictionary.com)
  • An early embryonic form created by cleavage of a fertilized ovum and comprising a spherical layer of cells surrounding a fluid-filled hole. (azdictionary.com)
  • an early on embryonic kind from cleavage of a fertilized ovum and composed of a spherical layer of cells surrounding a fluid-filled cavity. (azdictionary.com)
  • One troubling aspect of their distribution is that they are all only in the cleavage stage: we don't see any gastrulas, the stage at which embryonic cells undergo shape changes and begin to move in a specific, directed manner. (freethoughtblogs.com)
  • Cleavage differs from other forms of cell division in that it increases the number of cells without increasing the mass. (academic.ru)
  • Rotational cleavage involves a normal first division along the meridional axis, giving rise to two daughter cells. (academic.ru)
  • The way in which this cleavage differs is that one of the daughter cells divides meridionally, whilst the other divides equatorially. (academic.ru)
  • The embryonic cells - blastomeres - become smaller with each cleavage division. (princeton.edu)
  • Another important question is that the blastocyst biopsy cells are removed from the trophoectoderm while inbiopsy incleavage stage, the removal of oneblastomerecan impairembryonic development. (elsevier.es)
  • Cells that form from cell divisions (cleavages) are called blasters. (babyhelp411.com)
  • It is produced by cleavage of a fertilized ovum and consists of a spherical layer of around 128 cells surrounding a central fluid-filled cavity called the blastocoel. (githubusercontent.com)
  • Wilson shook apart the cells at early stages of embryonic development, and he observed the development of the isolated cells. (asu.edu)
  • Wilson obtained high quality images of egg cells by cutting the cells into thin sections and preserving them throughout different stages of development. (asu.edu)
  • What happens to the cells size as cleavage occurs? (brainscape.com)
  • What potency are the cells after cleavage? (brainscape.com)
  • The stage of the cells to browser rat becomes stem invasion newspapers. (hooligani.ru)
  • They were however distinct from the cleavage stage embryonic cells and/or the unfertilized ovum, they stemmed from. (jax.org)
  • They correspond both cytologically and developmentally to ectodermal embryonic cells from the egg-cylinder, the most advanced developmental stage of parthenotes observed previously in the ovary of LT mice. (jax.org)
  • Acting as nurse cells, choanocytes transport the sperm body without tail to the mature ova that wait in the mesogloea. (iaszoology.com)
  • Subsequent plates contain images of the various stages of fertilization , and the last plate contains photographs of the newly divided cells after fertilization . (asu.edu)
  • The methods included cutting very thin sections of a sea urchin ( Toxopneustes variegatus ) egg cells during key stages in development and preserving and staining them to make cellular structures visible when viewed through a microscope . (asu.edu)
  • These observations suggest that the immunological synapse in native tissues is remarkably fluid, and that stable synapses form only at specific stages of antigen presentation to T cells. (rupress.org)
  • Sperm and ova are produced from wandering amoeboid cells. (gulpmatrix.com)
  • During cleavage process, this newly formed fertilized ovum will divide rapidly into many cells and lead to blastula, which in mammals is called the blastocyst. (knowswhy.com)
  • Diagrams showing the position of the blastopore at successive stages of gastrulation in the frog's egg. (edu.au)
  • Diagrams of median sagittal sections through an eight-cell stage and four stages during gastrulation of the frog's egg. (edu.au)
  • Postero-lateral views of successive stages following gastrulation in the frog. (edu.au)
  • It is formed during the process called gastrulation, which precede the organogenesis stage. (knowswhy.com)
  • From here the spatial arrangement of blastomeres can follow various patterns, due to different planes of cleavage, in various organisms: The end of cleavage is known as midblastula transition and coincides with the onset of zygotic transcription. (wikipedia.org)
  • Blastomeres are produced through cleavage, a type of cell division, of the ovum after fertilisation. (sciencephoto.com)
  • The spherical embryonic mass of blastomeres formed before the blastula and resulting from cleavage of the fertilized ovum. (thefreedictionary.com)
  • From here the spatial arrangement of blastomeres can follow various patterns, due to different planes of cleavage, in various organisms. (academic.ru)
  • In holoblastic eggs, the first cleavage always occurs along the vegetal-animal axis of the egg, and the second cleavage is perpendicular to the first. (wikipedia.org)
  • holoblastic ovum one that undergoes total cleavage. (thefreedictionary.com)
  • [ 2 ] These holoblastic cleavage planes pass all the way through isolecithal zygotes during the process of cytokinesis. (academic.ru)
  • Cleavage is holoblastic and radial forming different types of blastula and gastrula. (iaszoology.com)
  • Prior to fertilization, each ovum, as a gamete, contains half of the genetic material that will fuse with the male gamete, which carries the other half of the genetic material (DNA). (wikipedia.org)
  • The male gamete is the sperm , and the female is ovum . (wikipedia.org)
  • In oogenesis, meiosis II, like meiosis I, is asymmetric, yielding a single ovum or egg, the single gamete arising from the primary oocyte, and two other polar bodies. (nanobukva.ru)
  • Ten hr after coitus, the ova advanced to metaphase of the meiosis II just before ovulation. (go.jp)
  • Studies on early stages of development indicate that human oocytes are usually fertilized with 12 hours after ovulation. (princeton.edu)
  • These include changes in the timing of ovum collection, changes in the types and numbers of ovulation-inducing agents, in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) as part of IVF, and types of culture media used. (springeropen.com)
  • Growth of the Ovarian Ovum, Maturation, Fertilisation and Early Cleavage. (biologists.com)
  • Earlier studies have shown that this test can select oocytes with superior quality in some species such as the pig, goat, bovine, mouse, and dog in terms of nuclear maturation, cleavage rate and blastocyst yield (Ericsson et al. (thefreedictionary.com)
  • One set of chromosomes came from the nucleus of the ovum and the second set from the nucleus of the sperm. (wikipedia.org)
  • The nucleus of the mature ovum becomes the female pronucleus. (thefreedictionary.com)
  • When the plasma membrane of the sperm cell contacts the plasma membrane of the ovum, they become continuous, and the nucleus of the sperm cell moves into the cytoplasm of the ovum. (ormedmedical.us)
  • The sperm nucleus then fuses with the nucleus of ovum, ensuring internal fertilization. (iaszoology.com)
  • These results are the first to reveal significant biochemical alterations that accompany the morphological and cytological differences previously described and indicate that the 8-cell stage nucleus is unable to completely recapitulate the normal progression of changes in protein synthesis pattern that occur during the 2-cell stage. (cshl.edu)
  • Our results indicate that developmental arrest may result from a combination of (1) failure to re-activate genes that normally become repressed between the 2-cell and 8-cell stages and (2) failure to up-regulate genes that become repressed during reprogramming of the 8-cell nucleus by the 1-cell cytoplasm. (cshl.edu)
  • In 1875, researcher Oscar Hertwig in Germany discovered that the nucleus of the sperm cell unites with the nucleus of an egg cell to form a single parent nucleus called a cleavage- nucleus . (asu.edu)
  • This broadened experience in comparative morphology turned Brachet's attention to the earliest stages of development-the first cleavage of the fertilized ovum, the early differentiation of the embryonic area, and the beginnings of the head and trunk. (encyclopedia.com)
  • Modified Poisson regression modeled the relative risk (RR) of having a male compared to a female among PGT blastocyst transfers versus non-PGT cleavage and blastocyst transfers adjusting for age, BMI, smoking status, race, parity, number of oocytes retrieved, and clinic region. (cdc.gov)
  • The results of fertilization are (a) restoration of the diploid number of chromosomes , (b) determination of chromosomal sex , and (c) initiation of cleavage . (princeton.edu)
  • At the following stage, diplotene, the two chromosomes in each tetrad begin to repel one another. (nanobukva.ru)
  • The processes of karyokinesis (mitosis) and cytokinesis work together to result in cleavage. (academic.ru)
  • Considered a founder of modern embryology, he discovered the notochord as well as the mammalian ovum. (thefreedictionary.com)
  • primitive ovum ( primordial ovum ) any oocyte very early in its development. (thefreedictionary.com)
  • Radial cleavage is characteristic of the deuterostomes, which include some vertebrates and echinoderms , in which the spindle axes are parallel or at right angles to the polar axis of the oocyte . (academic.ru)
  • Human development is a continuous process that begins when an oocyte (ovum) from a female is fertilized by a sperm (spermatozoon) from a male. (princeton.edu)
  • in humans, the stage approximately from attachment of the fertilized egg to the uterine wall until about the eighth week of pregnancy. (thefreedictionary.com)
  • blastula implantws in uterine endometrium -now called trophoblast (outside sphere that will be placenta) and embryoblast (inner cell mass). blastula = an early stage of embryonic development in animals. (livejournal.com)
  • Three stages in spermatogenesis in man (negro). (edu.au)
  • The L1 stage usually occurs within four to six days under the optimal conditions of 24-29 °C. The L2 rhabditform sheds its cuticle and then develops into the L3 filiariform infective larvae. (wikipedia.org)
  • In This Article The process of prenatal development occurs in three main stages. (johnnydeppnetwork.com)
  • This may partially account for the need to delay the widespread activation of zygotic gene transcription until the 2-cell stage, when much of the nuclear remodeling that occurs postfertilization is complete. (cshl.edu)
  • The book presents photographs by photographer Edward Leaming that capture stages of fertilization, the fusion of sperm and egg and early development of sea urchin (Toxopneustes variegatus) ova, or egg cell. (asu.edu)
  • Offspring is made by a sperm fertilizing an ovum from the female involves meiosis is very slow method of multiplication. (wikipedia.org)
  • The last stage of sperm penetration into the egg involves the attachment of the sperm head to the surface of the vitelline membrane . (blogspot.com)
  • Sexual reproduction involves formation of sperms and ova. (iaszoology.com)
  • During their passage through the female reproductive tract, the sperm gain the ability to fertilize an ovum. (ormedmedical.us)
  • A woman usually ovulates only one ovum a month, for a total of less than 450 ova during her reproductive years. (ormedmedical.us)
  • We cultured ova to the blastocyst stage in a mouse model in culture media with four different amino acid constituents. (springeropen.com)
  • Prenatal development starts with fertilization the first stage in embryogenesis which continues in fetal development until birth. (wikipedia.org)
  • In mammals, the term refers chiefly to the early stages of prenatal development, whereas the terms fetus and fetal development describe later stages. (wikipedia.org)
  • Anatomical entity that comprises the organism in the early stages of growth and differentiation that are characterized by cleavage, the laying down of fundamental tissues, and the formation of primitive organs and organ systems. (githubusercontent.com)
  • In later stages, development across all taxa of animals and the length of gestation vary. (wikipedia.org)
  • The Y chromosome contains a gene, SRY, which will switch on androgen production at a later stage, leading to the development of a male body type. (wikipedia.org)
  • Embryonic development starts with the fertilization of an egg cell (ovum) by a sperm cell, (spermatozoon). (wikipedia.org)
  • Embryonic LPA production into culture medium was also detected at both stages of development. (hindawi.com)
  • 1. An animal in its earliest stages of development, especially in the uterus of female mammals, or, in egg-laying animals, an animal developing in the egg until it is hatched. (thefreedictionary.com)
  • 2. A plant in its earliest stages of development, especially the miniature, partially developed plant contained within a seed. (thefreedictionary.com)
  • 1. A plant or animal that is at an early stage of its development. (thefreedictionary.com)
  • Coeloblastula is the next stage of development for eggs that undergo these radial cleavaging. (academic.ru)
  • What are the four stages of embryonic development? (johnnydeppnetwork.com)
  • The developing human during its early stages of development. (princeton.edu)
  • Stages of embryonic development of the zebrafish. (nih.gov)
  • Stages are named, not numbered as in most other series, providing for flexibility and continued evolution of the staging series as we learn more about development in this species. (nih.gov)
  • Other figures chart the development of distinctive characters used as staging aid signposts. (nih.gov)
  • ontogeny recapitulates phylogeny" gave weight to the theory of evolution (see recapitulation recapitulation, theory, stated as the biogenetic law by E. H. Haeckel, that the embryological development of the individual repeats the stages in the evolutionary development of the species. (thefreedictionary.com)
  • This tendency is justified by the larger amount of genetic material available in an advanced stage of embryonic development. (elsevier.es)
  • Demonstrate the knowledge of the basic principles and sequential development of the organs and systems, recognize the critical stages of development and effects of common teratogens, genetic mutations and environmental hazards. (edu.in)
  • an animal at an early stage of development, before birth. (richardsonthebrain.com)
  • the early stages of development in a multicellular organism during which the organization of the organism is largely formed. (richardsonthebrain.com)
  • Early development takes place within maternal sponge body leading to the formation of a larval stage. (iaszoology.com)
  • The anatomical parts that make up an organism in the early stages of development. (umassmed.edu)
  • An Atlas helped Wilson develop methods to present key stages of fertilization and development, which he later used in his textbook The Cell in Development and Inheritance , first published in 1896. (asu.edu)
  • Furthermore, An Atlas was the first publication to present accurate images of the fertilized egg cell during early stages of development. (asu.edu)
  • I the descriptive section, Wilson presents photographs and diagrams of the egg cell throughout different stages of development. (asu.edu)
  • Within this, the early stages of development take place. (gulpmatrix.com)
  • And yet, the human babies are the exact same people, no matter their stage of development. (abortionexploitswomen.com)
  • Eggs then develop in moist conditions in the feces and continue to develop into the L1 (rhabditiform), and L2 juvenile stages by feeding on bacteria in the dung. (wikipedia.org)
  • Mammalian ova have not been studied as thoroughly as the eggs of lower vertebrates. (biologists.org)
  • sperm A sperm cell attempting to penetrate an egg (ovum) to fertilize it. (britannica.com)
  • Based on the expression of ICM (Sox2) and trophectoderm (Cdx2) markers, it was determined that ICM marker was lacking in blastocysts derived from 12% of BTMs from two-cell stage and 20% from four-cell stage. (biomedsearch.com)
  • Fertilization of the egg cell (ovum), usually takes place in one of the Fallopian tubes. (wikipedia.org)
  • Many sperm are released with the possibility of just one sperm cell managing to adhere to and enter the thick protective shell-like layer surrounding the ovum. (wikipedia.org)
  • Mammals at this stage form a structure called the blastocyst,[1] characterized by an inner cell mass that is distinct from the surrounding blastula. (wikipedia.org)
  • Fertilization of the ovum (egg cell ) usually takes place in the Fallopian tube. (bionity.com)
  • Here, the cell at centre is in the anaphase stage of mitotic division. (sciencephoto.com)
  • The term is sometimes applied to any stage of the fertilized germ cell during cleavage and even until hatching or birth of the new individual. (thefreedictionary.com)
  • Reported here are the dry mass and protein and lipid contents of the single cell fertilized mouse ovum. (biologists.org)
  • Single cell stage ova from mated females were chosen as the starting point from which to follow these parameters through cleavage and blastocyst formation, although it must be realized that a proportion of such ova would not be fertilized. (biologists.org)
  • Embryogenesis starts with the fertilization of the egg cell (ovum) by a sperm cell, (spermatozoon). (wn.com)
  • sperm penetrates the cell membrane of ovum. (wikipedia.org)
  • Approximately half of these alterations involve proteins that normally decrease in synthesis between the 2-cell and 8-cell stages and half involve proteins that are synthesized constitutively between these two stages. (cshl.edu)
  • The failure to up-regulate the synthesis of proteins expressed at both the 2-cell and the 8-cell stages may indicate that, for some genes, a transcriptionally inactive state, possibly related to a particular chromatin configuration, may serve a protective function by restricting access of factors that can permanently reduce the ability of a gene to be expressed. (cshl.edu)
  • Altered patterns of T cell motility during this early stage of antigen recognition promoted serial engagement with several adjacent DCs. (rupress.org)
  • Subsequently, T cell behavior progressed through additional distinct stages, including long-lived clusters, dynamic swarms, and finally autonomous migration punctuated by cell division. (rupress.org)
  • Each ovum is formed from a single cell which enlarges and becomes spherical. (gulpmatrix.com)
  • After cleavage, an ovoid blastula is formed, wholly or partly covered with flagellated cell' this is released into the water as a free-swimming larva and thus dispersal of the species is effected. (gulpmatrix.com)
  • This can occur naturally at the two cell stage to give identical twins. (chipbennett.net)
  • In other animals the very early stages of embryogenesis are the same as those in humans. (wikipedia.org)
  • Blastula is formed from morola and it is the first stage in the embryogenesis formed from blastulation. (knowswhy.com)
  • Up to now there have been no direct chemical analyses of mammalian ova published. (biologists.org)
  • The ovarian ova were found to be in prophase of the meiosis I in estrus but unmated females, and entered into metaphase of the meiosis I 5 hr after coitus. (go.jp)
  • 10. What is the multicellular ball that is formed during cleavage called? (slideserve.com)
  • The mouse was chosen because of its frequent use as an experimental animal for the study of developmental genetics and because large numbers of mouse ova can be obtained with relative ease. (biologists.org)
  • The following cleavage planes are centered on this axis and result in the two halves being mirror images of one another. (academic.ru)
  • The ovum only carries the X female sex chromosome whilst the sperm carries a single sex chromosome of either an X or a male Y chromosome. (wikipedia.org)
  • In a majority of Turkey's female abuse cases, the perpetrators receive mitigations in their sentences due to court's detection of consent granted by the victim, in some cases, wearing a miniskirt or some cleavage got the woman's rapist mitigation in his punishment, while in some cases the consent was attached to her wearing red. (definitions.net)
  • they must be present in the female tract for at least 7 hours before they can fertilize an ovum. (ormedmedical.us)
  • The period of two weeks from fertilization is also referred to as the germinal stage. (wikipedia.org)
  • Contents Germinal stage. (johnnydeppnetwork.com)
  • The first two weeks after conception are known as the germinal stage, the third through the eighth week is known as the embryonic period, and the time from the ninth week until birth is known as the fetal period. (johnnydeppnetwork.com)