Cleavage stage ovum. Medical search

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

Undifferentiated cells resulting from cleavage of a fertilized egg (ZYGOTE). Inside the intact ZONA PELLUCIDA, each cleavage yields two blastomeres of about half size of the parent cell. Up to the 8-cell stage, all of the blastomeres are totipotent. The 16-cell MORULA contains outer cells and inner cells.

A post-MORULA preimplantation mammalian embryo that develops from a 32-cell stage into a fluid-filled hollow ball of over a hundred cells. A blastocyst has two distinctive tissues. The outer layer of trophoblasts gives rise to extra-embryonic tissues. The inner cell mass gives rise to the embryonic disc and eventual embryo proper.

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

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

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

Morphological and physiological development of EMBRYOS.

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

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

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

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

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

Endometrial implantation of EMBRYO, MAMMALIAN at the BLASTOCYST stage.

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

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

An early non-mammalian embryo that follows the MORULA stage. A blastula resembles a hollow ball with the layer of cells surrounding a fluid-filled cavity (blastocele). The layer of cells is called BLASTODERM.

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

Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).

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

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

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

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

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

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

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

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

Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.

The developmental stage that follows BLASTULA or BLASTOCYST. It is characterized by the morphogenetic cell movements including invagination, ingression, and involution. Gastrulation begins with the formation of the PRIMITIVE STREAK, and ends with the formation of three GERM LAYERS, the body plan of the mature organism.

Morphological and physiological development of EMBRYOS or FETUSES.

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

Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.

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

The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.

The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.

The complex processes of initiating CELL DIFFERENTIATION in the embryo. The precise regulation by cell interactions leads to diversity of cell types and specific pattern of organization (EMBRYOGENESIS).

Proteins obtained from various species of Xenopus. Included here are proteins from the African clawed frog (XENOPUS LAEVIS). Many of these proteins have been the subject of scientific investigations in the area of MORPHOGENESIS and development.

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

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

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

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

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

The processes occurring in early development that direct morphogenesis. They specify the body plan ensuring that cells will proceed to differentiate, grow, and diversify in size and shape at the correct relative positions. Included are axial patterning, segmentation, compartment specification, limb position, organ boundary patterning, blood vessel patterning, etc.

The outer of the three germ layers of an embryo.

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

Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)

RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.

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

The condition of carrying two or more FETUSES simultaneously.

A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.

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

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

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

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

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

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

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

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

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

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

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

The development of anatomical structures to create the form of a single- or multi-cell organism. Morphogenesis provides form changes of a part, parts, or the whole organism.

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

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

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

The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.

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

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

Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.

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

The rate dynamics in chemical or physical systems.

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

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

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

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

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

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

Established cell cultures that have the potential to propagate indefinitely.

Proteins prepared by recombinant DNA technology.

A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).

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

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

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

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

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

Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.

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

Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Proteins found in any species of virus.

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

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

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

The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.

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

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

Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.

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

Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.

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

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

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

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

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

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

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

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

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

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

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

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

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

Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.

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

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

Physiologically inactive substances that can be converted to active enzymes.

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

Chromosome abnormalities in human embryos. (1/708)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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 ...

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

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 ...

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

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

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

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 ...

https://simple.wikipedia.org/wiki/Sexual_reproduction

... 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 ...

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

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 ...

https://en.m.wikipedia.org/wiki/Embryogenesis

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 ...

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

... 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]. ...

https://en.m.wikipedia.org/wiki/Egg_

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 ...

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

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, ...

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

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 ...

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

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] ...

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

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 ...

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

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 ...

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

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 ...

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

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 ...

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

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. ...

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

The oral-aboral axis is specified early in cleavage, and the left-right axis appears at the late gastrula stage.[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 ...

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

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 ...

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

... 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 ...

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

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) ...

https://en.m.wikipedia.org/wiki/Animalia

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

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

https://en.m.wikipedia.org/wiki/Metazoan

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 ...

https://www.britannica.com/science/prenatal-development

Ovum cleavage stage‎ (7 F). S. *. ► Cell division on stamps‎ (2 F) ...

https://commons.wikimedia.org/wiki/Category:Cell_division

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 ...

https://pubmed.ncbi.nlm.nih.gov/3311851/?dopt=Abstract

... 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. ...

https://pubmed.ncbi.nlm.nih.gov/19140288/?dopt=Abstract

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 ...

http://www.biomedsearch.com/nih/Development-single-mouse-blastomeres-into/18502895.html

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 ...

http://www.biomedsearch.com/nih/Multinucleation-cleavage-embryos-derived-from/16769057.html

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

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

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

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 ...

https://www.hindawi.com/journals/mi/2014/678968/

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. ...

https://www.bionity.com/en/encyclopedia/Prenatal_development.html

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 ...

http://www.sciencephoto.com/media/460952/view/fish-embryo-development-light-micrograph

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 ...

http://ronshimek.com/blog/?tag=invertebrates

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. ...

http://ronshimek.com/blog/?tag=dermasterias-imbricata

... 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 ...

https://www.ivis.org/library/bubaline-theriogenology/reproduction-swamp-buffalo-bubalus-bubalis

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. ...

https://medical-dictionary.thefreedictionary.com/morulas

... 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 ...

https://www.britannica.com/science/zygote

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 ...

http://medical-dictionary.thefreedictionary.com/isolecithal+ovum

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 ...

https://www.slideserve.com/wendi/fertilization

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 ...

https://www.thefreedictionary.com/blastocyst

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), ...

https://www.shopanatomical.com/School_Set_D_Supplement_for_A_B_and_C_Microsco_p/3b-w134389.htm

... 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 ...

https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/brachet-albert

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 ...

https://www.thefreedictionary.com/embryo

Growth of the Ovarian Ovum, Maturation, Fertilisation and Early Cleavage. Transactions of the Zoological Society of London, 24 ...

http://thenode.biologists.com/tag/evo-devo/

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- ...

http://www.jimmunol.org/content/201/2/734

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 ]. ...

http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892010000100008&lng=en&nrm=iso&tlng=en

... 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 ...

http://dev.biologists.org/content/12/1/113

Transfer of blastocysts derived from frozen-thawed cleavage stage embryos improved ongoing pregnancy. ...

https://www.springermedizin.de/a-short-narrative-review-of-the-feasibility-of-adopting-mild-ova/8424188?fulltextView=true&doi=10.1007%2Fs00404-012-2347-x

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 ...

https://upge.wn.com/?query=human_womb_it&pagenum=2&language_id=5&template=international%2Fanything.txt

https://simple.wikipedia.org/wiki/Sexual_reproduction

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)

meroblastic ovum one that undergoes partial cleavage. (thefreedictionary.com)
An ovum that undergoes complete cleavage, as opposed to partial or meroblastic cleavage. (thefreedictionary.com)
compared with bilateral meroblastic cleavage, in which the blastomeres stay partially connected. (academic.ru)

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)

A mature ovum is about 0.13 to 0.14 mm (0.0051 to 0.0055 in) in diameter. (thefreedictionary.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 the vertebrates, however, the gastrula stage is so modified that it is recognizable only with difficulty. (encyclopedia.com)
Blastula and gastrula represent the important stages of the embryonic development in animals. (knowswhy.com)
As highlighted already, gastrula is the embryonic development stage preceded by blastula. (knowswhy.com)

Organism at the blastula stage - an early stage of embryonic development in animals. (githubusercontent.com)
Oxford) Also referred to as the 'blastula stage of development. (richardsonthebrain.com)

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)

The ovum develops from an oogonium within the graafian follicle of the ovary and matures through the meiotic process of oogenesis. (thefreedictionary.com)

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)

Anatomy23

Organisms10

Diseases7

Chemicals and Drugs45

Analytical, Diagnostic and Therapeutic Techniques and Equipment17

Phenomena and Processes47

Information Science4

Health Care2

Chromosome abnormalities in human embryos. (1/708)

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

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

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

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

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

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

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

Cleavage Stage, Ovum

Blastomeres

Blastocyst

Ovum

Embryo Culture Techniques

Embryo Transfer

Embryonic Development

Vitrification

Zygote

Preimplantation Diagnosis

Embryo, Nonmammalian

Fertilization in Vitro

Embryo Implantation

Cryopreservation

Polar Bodies

Blastula

Embryo, Mammalian

Oocytes

Urochordata

Ovalbumin

Sea Urchins

Ovum Transport

Pregnancy

Morula

Pregnancy Rate

Fetal Viability

Molecular Sequence Data

Gastrula

Embryonic and Fetal Development

Fertilization

Gene Expression Regulation, Developmental

Germ Layers

Amino Acid Sequence

Xenopus laevis

Embryonic Induction

Xenopus Proteins

DNA Cleavage

Base Sequence

Aneuploidy

Sperm Injections, Intracytoplasmic

Xenopus

Body Patterning

Ectoderm

Octamer Transcription Factor-3

Cell Nucleus

RNA, Messenger

RNA Cleavage

Pregnancy, Multiple

In Situ Hybridization

Zebrafish

Oogenesis

Time Factors

Mesoderm

Zebrafish Proteins

Substrate Specificity

Hydrolysis

Cytoplasm

Endopeptidases

Transcription Factors

Cells, Cultured

Morphogenesis

Peptide Fragments

Protein Processing, Post-Translational

In Situ Hybridization, Fluorescence

Signal Transduction

Transcription, Genetic

Binding Sites

DNA-Binding Proteins

Cell Differentiation

Kinetics

Furin

Caspases

mRNA Cleavage and Polyadenylation Factors

Serine Endopeptidases

Immunoglobulin E

Allergens

Protein Precursors

Cell Line

Recombinant Proteins

DNA