Cleavage Stage, Ovum
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.
Blastomeres
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.
Blastocyst
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.
Embryo Culture Techniques
Embryo Transfer
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.
Vitrification
Preimplantation Diagnosis
Embryo, Nonmammalian
Fertilization in Vitro
Cryopreservation
Polar Bodies
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)
Blastula
Embryo, Mammalian
Oocytes
Urochordata
Sea Urchins
Ovum Transport
Pregnancy
Morula
Pregnancy Rate
Fetal Viability
Molecular Sequence Data
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.
Gastrula
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.
Fertilization
Gene Expression Regulation, Developmental
Germ Layers
Amino Acid Sequence
Xenopus laevis
Embryonic Induction
Xenopus Proteins
DNA Cleavage
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.
Base Sequence
Aneuploidy
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).
Sperm Injections, Intracytoplasmic
Xenopus
Body Patterning
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.
Octamer Transcription Factor-3
Cell Nucleus
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, Messenger
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.
RNA Cleavage
In Situ Hybridization
Zebrafish
Oogenesis
Mesoderm
Zebrafish Proteins
Substrate Specificity
Cytoplasm
Endopeptidases
Transcription Factors
Cells, Cultured
Morphogenesis
Peptide Fragments
Protein Processing, Post-Translational
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.
In Situ Hybridization, Fluorescence
Signal Transduction
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.
Transcription, Genetic
Binding Sites
DNA-Binding Proteins
Cell Differentiation
Furin
Caspases
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.
mRNA Cleavage and Polyadenylation Factors
Serine Endopeptidases
Immunoglobulin E
Allergens
DNA
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).
Bronchial Hyperreactivity
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.
Nucleic Acid Conformation
Caspase 3
Escherichia coli
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, Catalytic
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.
Mutation
Apoptosis
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.
Respiratory Hypersensitivity
Cysteine Endopeptidases
Endoribonucleases
Electrophoresis, Polyacrylamide Gel
Retrospective Studies
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.
Peptide Hydrolases
Cholesterol Side-Chain Cleavage Enzyme
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.
Proteolysis
Amyloid Precursor Protein Secretases
Protein Structure, Tertiary
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.
Catalysis
Bronchoalveolar Lavage Fluid
Protein Binding
Trypsin
Plasmids
Mutagenesis, Site-Directed
Peptides
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.
Aspartic Acid Endopeptidases
Th2 Cells
Asthma
Eosinophils
Cattle
Models, Molecular
Mice, Transgenic
Hypersensitivity
Superovulation
Lung
RNA Precursors
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.
Enzyme Activation
Pulmonary Eosinophilia
Cloning, Molecular
RNA Processing, Post-Transcriptional
Calpain
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.
Membrane Proteins
HeLa Cells
Recombinant Fusion Proteins
Deoxyribonucleases, Type II Site-Specific
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.
Cricetinae
Immune Tolerance
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.
Poly(ADP-ribose) Polymerases
DNA Topoisomerases, Type II
Mice, Knockout
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.
Protein Conformation
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).
Antigen Presentation
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)
Disease Models, Animal
Adjuvants, Immunologic
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.
Protease Inhibitors
Sequence Homology, Amino Acid
DNA Restriction Enzymes
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.
ADAM Proteins
Endonucleases
Structure-Activity Relationship
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)
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What is a Zygote? - Definition from FertilitySmarts
Timeline of human prenatal development
This mitosis is also known as cleavage. A hollow cavity forms marking the blastocyst stage. (day 1.5-3 of fertilization.) The ... Fertilization of the ovum to form a new human organism, the human zygote. (day 1 of fertilization) The zygote undergoes mitotic ... Wagner F, Erdösová B, Kylarová D (December 2004). "Degradation phase of apoptosis during the early stages of human metanephros ...
Euplectella
Fertilization occurs when the sperm reaches the ovum. The zygote experiences radial holoblastic cleavage and eventually forms ... Euplectella experiences two main life stages: the larval stage or the adult stage. In the larval stage, the larvae is free ... In the adult stage, Euplectella are sessile and attached firmly to rocks through spicules. It is unclear how long Euplectella ...
Trichoplax
Usually even before its liberation, the ovum initiates cleavage processes in which it becomes completely pinched through at the ... Development beyond this 256-cell stage has not yet been observed. Trichoplax lack a homologue of the Boule protein that appears ... Once maturation of the ovum is complete, the rest of the animal degenerates, liberating the ovum itself. Small, unciliated ... In the protected interior space, the ventral cells form an ovum surrounded by a special envelope, the fertilisation membrane; ...
Haemonchus contortus
The ova is yellowish in color. The egg is about 70-85 μm long by 44 μm wide, and the early stages of cleavage contain between ... and L2 juvenile stages by feeding on bacteria in the dung. The L1 stage usually occurs within four to six days under the ... "The role of the sheath in resistance of Haemonchus contortus infective stage larvae to proteolytic digestion". Veterinary ...
Animal embryonic development
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 ...
List of MeSH codes (A16)
... cleavage stage, ovum MeSH A16.254.300.600.274 - blastula MeSH A16.254.300.600.550 - morula MeSH A16.254.300.800 - yolk sac MeSH ... cleavage stage, ovum MeSH A16.254.270.274 - blastula MeSH A16.254.270.550 - morula MeSH A16.254.283 - cloaca MeSH A16.254.300 ...
Human embryonic development
The germinal stage takes around 10 days. During this stage, the zygote begins to divide, in a process called cleavage. A ... With the sperm adhered to the ovum, the third process of acrosomal reaction takes place; the front part of the spermatozoan ... Cleavage itself is the first stage in blastulation, the process of forming the blastocyst. Cells differentiate into an outer ... The germinal stage refers to the time from fertilization through the development of the early embryo until implantation is ...
Blastocoel
"blastocoel...[blaso- + -coele] the fluid-filled cavity of the mass of cells (blastula) produced by cleavage of fertilized ovum ... cell stage is considered a blastula as the blastocoel in the embryo becomes apparent during this stage. The fluid-filled cavity ... At this stage there is no cavity within the morula; the embryo is still a ball of dividing cells. In a process called ... At this stage in mammals the blastula develops into the blastocyst containing an inner cell mass, and outer trophectoderm. It ...
Sciara (fly)
Soma line is the vegetative stage. During early cleavage stages of the embryo limited chromosomes are eliminated. The number of ... In the formation ova of the females the 1st ovarian division is monocentric mitosis, the maternal and paternal homologous ... In the next stage of cleavage one paternal X chromosome is eliminated. Hence female soma line cells have 3 pairs of autosomes ... Some special chromosomes called limited chromosomes are present in certain stages. The zygote has 3 pairs of autosomes a one or ...
Development of the human body
The germinal stage takes around 10 days. During this stage, the zygote begins to divide, in a process called cleavage. A ... Fertilisation occurs when the sperm cell successfully enters and fuses with an egg cell (ovum). The genetic material of the ... Briefly, embryonic development have four stages: the morula stage, the blastula stage, the gastrula stage, and the neurula ... The egg becomes a zygote and the germinal stage of embryonic development begins. The germinal stage refers to the time from ...
Taenia solium
Spermatozoa fuse with the ova in the fertilisation duct, where the zygotes are produced. The zygote undergoes holoblastic and ... However, humans can also act as secondary hosts, which is a more pathological, harmful stage triggered by oral contamination. ... unequal cleavage resulting in three cell types, small, medium and large (micromeres, mesomeres, megameres). Megameres develop ... Humans are colonised by the larval stage, the cysticercus, from undercooked pork or other meat. Each microscopic cysticercus is ...
Nemertea
Temporary gonoducts (ducts from which the ova or sperm are emitted), one per gonad, are built when the ova and sperm are ready ... This larval stage is unique in that there are no Hox genes involved during development, which are only found in the juveniles ... The fertilized egg divides by spiral cleavage and grows by determinate development, in which the fate of a cell can usually be ... The planuliform larva stage may be short-lived and lecithotrophic ("yolky") before becoming a juvenile, or may be ...
Heterogonesis
"Zygotes segregate entire parental genomes in distinct blastomere lineages causing cleavage-stage chimerism and mixoploidy". ... Fertilisation occurs when an ovum fuses with a sperm, forming a zygote. Normally, the genomes of the two parents assort into ...
Cytokinesis
Stage of a cell division Metaphase - Stage of cell division Mitosis - Process in which replicated chromosomes are separated ... constricting the cell membrane to form a cleavage furrow. Continued hydrolysis causes this cleavage furrow to ingress (move ... for example in oogenesis in animals the ovum takes almost all the cytoplasm and organelles. This leaves very little for the ... Diploid Telophase - Final stage of a cell division for eukaryotic cells both in mitosis and meiosis Prophase - First phase of ...
Egg
... of a motile stage. The zygote or the ovum itself or the sessile organic vessel containing the developing embryo may be called ... The yolk is evenly distributed, so the cleavage of the egg cell cuts through and divides the egg into cells of fairly similar ... In cnidarians, this stage is called the planula, and either develops directly into the adult animals or forms new adult ... The fetus instead develops as a plate-like structure on top of the yolk mass, and only envelopes it at a later stage. A portion ...
Zygote
This stage has also been referred to as the pre-embryo in legal discourses including relevance to the use of embryonic stem ... In the fertilized daughter, DNA is then replicated in the two separate pronuclei derived from the sperm and ovum, making the ... in a process called cleavage. After four divisions, the conceptus consists of 16 blastomeres, and it is known as the morula. ... Between the stages of fertilization and implantation, the developing embryo is sometimes termed as a preimplantation-conceptus ...
Isolecithal
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 ...
Eucestoda
Yolk cells travel in a duct system to the oviduct, where, in a modified region, the ovum is enclosed in a shell with yolk cells ... After the scolex has differentiated and matured in the larval stage, growth will stop until a vertebrate eats the intermediate ... The initial six-hooked embryo, known as an oncosphere or hexacanth, forms through cleavage. In the order Pseudophyllidea, it ... Eucestoda ontogenesis continues through metamorphosing in different larval stages inside different hosts. ...
Embryology
Holoblastic cleavage can be radial (see: Radial cleavage), spiral (see: Spiral cleavage), bilateral (see: Bilateral cleavage), ... In the first stage, the semen predominates. In the second stage, the embryo is filled with blood. In the third stage, the main ... Until the birth of modern embryology through observation of the mammalian ovum by Karl Ernst von Baer in 1827, there was no ... Meroblastic cleavage can be bilateral (see: Bilateral cleavage), discoidal (see: Discoidal cleavage), or centrolecithal (see: ...
Germ cell
... stages of meiosis. The long period of meiotic arrest at the four chromatid dictyate stage of meiosis may facilitate ... Germ cell specification begins during cleavage in many animals or in the epiblast during gastrulation in birds and mammals. ... ovum). The unfertilized egg of most animals is asymmetrical: different regions of the cytoplasm contain different amounts of ... The mouse oocyte in the dictyate (prolonged diplotene) stage of meiosis actively repairs DNA damage, whereas DNA repair was not ...
Crown-of-thorns starfish
... cleavage) (photograph). By 8-9 hours, it has reached the 64-cell stage. Some molecular and histological evidence suggests the ... In section, they are very different, with the ovaries densely filled with nutrient-packed ova (see ovum and photograph) and the ... To this stage ,the larva has been virtually transparent, but the posterior section is now opaque with the initial development ... Juveniles of A. planci that had reached the stage of feeding on coral were then reared for some years in the same large closed- ...
Cloning
It is optimally performed at the 6- to 8-cell stage, where it can be used as an expansion of IVF to increase the number of ... Dolly's embryo was created by taking the cell and inserting it into a sheep ovum. It took 435 attempts before an embryo was ... and Parton is known for her ample cleavage. The modern cloning techniques involving nuclear transfer have been successfully ... At an early growth stage when colonies consist of only a few cells, sterile polystyrene rings (cloning rings), which have been ...
In vitro fertilisation
The main durations of embryo culture are until cleavage stage (day two to four after co-incubation) or the blastocyst stage ( ... removing an ovum or ova (egg or eggs) from their ovaries and letting sperm fertilise them in a culture medium in a laboratory. ... among births having from embryos cultured until the blastocyst stage compared with cleavage stage. Laboratories have developed ... On the contrary, for women of advanced maternal age, PGS with cleavage-stage biopsy significantly lowers the live birth rate. ...
Meiosis
The first stage of prophase I is the leptotene stage, also known as leptonema, from Greek words meaning "thin threads".: 27 In ... which enlarges to become an ovum. Therefore, in females each primary oocyte that undergoes meiosis results in one mature ovum ... Nuclear envelopes re-form and cleavage or cell plate formation eventually produces a total of four daughter cells, each with a ... 27 is the stage at which all autosomal chromosomes have synapsed. In this stage homologous recombination, including chromosomal ...
Yolk
After the fertilization, the cleavage of the embryo leads to the formation of the germinal disc. As food, the chicken egg yolk ... All bony fish, some sharks and rays have yolk sacs at some stage of development, with all oviparous fish retaining the sac ... The yolk mass, together with the ovum proper (after fertilization, the embryo) are enclosed by the vitelline membrane, whose ... contrary to the claim that the avian ovum (in strict sense) and its yolk are a single giant cell. ...
Sea urchin
The oral-aboral axis is specified early in cleavage, and the left-right axis appears at the late gastrula stage. In most cases ... The transparency of the urchin's eggs enabled them to be used to observe that sperm cells actually fertilize ova. They continue ... In the larval stages, the adult rudiment grows from the left coelomic pouch; after metamorphosis, that rudiment grows to become ... During cleavage, mesoderm and small micromeres are specified. At the end of gastrulation, cells of these two types form ...
Annelid
Both of these systems use a two-stage filtration process, in which fluid and waste products are first extracted and these are ... Most polychaetes whose reproduction has been studied lack permanent gonads, and it is uncertain how they produce ova and sperm ... Hence this development pattern is often described as "spiral determinate cleavage". The term originated from Jean-Baptiste ... When their cells divide after the 4-cell stage, descendants of these four cells form a spiral pattern. In these phyla the " ...
Animal
The Spiralia are a large group of protostomes that develop by spiral cleavage in the early embryo. The Spiralia's phylogeny has ... The blastula is a stage in embryonic development that is unique to animals, allowing cells to be differentiated into ... non-motile gametes are ova. These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In ... Valentine, James W. (July 1997). "Cleavage patterns and the topology of the metazoan tree of life". PNAS. 94 (15): 8001-8005. ...
Homologous recombination
After the stages of resection, strand invasion and DNA synthesis, the DSBR and SDSA pathways become distinct. The DSBR pathway ... This cleavage is done by RuvAB complex interacting with RuvC, which together form the RuvABC complex. RuvC is an endonuclease ... In turn, nondisjunction can cause sperm and ova to have too few or too many chromosomes. Down's syndrome, which is caused by an ... Mimitou EP, Symington LS (May 2009). "Nucleases and helicases take center stage in homologous recombination". Trends in ...
Germline mutation
Errors in maternal ovum also occur, but at a lower rate than in paternal sperm. The types of mutations that occur also tend to ... The ZFN editing complex consists of a zinc finger protein (ZFP) and a restriction enzyme cleavage domain. The ZNP domain can be ... Germline mutations can occur before fertilization and during various stages of zygote development. When the mutation arises ... Endogenous mutations are more prominent in sperm than in ova. This is because spermatocytes go through a larger number of cell ...
Sponge
Most species use sexual reproduction, releasing sperm cells into the water to fertilize ova that in some species are released ... ISBN 978-1-84407-527-0. Jacobson N (2000). Cleavage. Rutgers University Press. p. 62. ISBN 978-0-8135-2715-4. "Sponges". ... while in larval stage of life they are motile . Although there are freshwater species, the great majority are marine (salt- ...
List of Otome wa Boku ni Koishiteru characters
She is the director of the drama club and during times on stage she has to be very forceful in order to get a good response out ... Yuu Kashiwagi (栢木 優雨, Kashiwagi Yū) Voiced by: Shion Hondaeri (PC), Ai Shimizu (PSP), Mana Hirata (OVA) Yuu is a new student in ... Throughout the anime, willing suspension of disbelief is employed, as there are severally scenes where Mizuho shows cleavage ( ... Despite being very nervous on the stage, but she is selected for the leading role at the school festival by Kei, who is the ...
Osteopontin
Full-length OPN (OPN-FL) can be modified by thrombin cleavage, which exposes a cryptic sequence, SVVYGLR on the cleaved form of ... The secreted form of Opn (Opn-s) plays a proinflammatory role during allergen sensitization (OVA/Alum), as neutralization of ... and disease stage-specific targeting. Although the exact mechanisms of osteopontin signaling in PDAC are unknown, it binds to ... an inhibition regulated by PHEX cleavage of ASARM". Journal of Bone and Mineral Research. 23 (10): 1638-1649. doi:10.1359/jbmr. ...
Echinoderm
At this stage the pentaradial symmetry develops. A plankton-eating larva, living and feeding in the water column, is considered ... The large size and the transparency of the eggs enables the observation of sperm cells in the process of fertilising ova. The ... On fracturing such rock, paleontologists can observe distinctive cleavage patterns and sometimes even the intricate internal ... Echinoderms have secondary radial symmetry in portions of their body at some stage of life, most likely an adaptation to a ...
Brachiopod
The authors found this surprising, since nemertines have spiral cleavage in the early stages of cell division and form a ... Ripe gametes (ova or sperm) float from the gonads into the main coelom and then exit into the mantle cavity. The larvae of ... Hence radial cleavage does not imply that brachiopods are affiliated with deuterostomes. The traditional view is that the ... The gonads are masses of developing gametes (ova or sperm), and most species have four gonads, two in each valve. Those of ...
Biology
The different stages of mitosis all together define the mitotic phase of an animal cell cycle-the division of the mother cell ... The zygote undergoes a rapid multiple rounds of mitotic cell period of cell divisions called cleavage, which forms a ball of ... The smaller, motile gametes are spermatozoa and the larger, non-motile gametes are ova. These fuse to form zygotes, which ... During the third stage of photosynthesis, the movement of protons down their concentration gradients from the thylakoid lumen ...
Menstrual cycle
It has reached the blastocyst stage at the time of implantation: this is when pregnancy begins. The loss of the corpus luteum ... The follicle that reaches maturity is called an antral follicle, and it contains the ovum (egg cell). The theca cells develop ... In the corpus luteum, cholesterol side-chain cleavage enzyme converts cholesterol to pregnenolone, which is converted to ... Menopause is preceded by a stage of hormonal changes called perimenopause. Eumenorrhea denotes normal, regular menstruation ...
Oocyte
The space within an ovum or immature ovum is located is the cell-nest. The cumulus-oocyte complex contains layers of tightly ... The oocyte is arrested in Meiosis II at the stage of metaphase II and is considered a secondary oocyte. Before ovulation, the ... "XPACE4 is a localized pro-protein convertase required for mesoderm induction and the cleavage of specific TGFbeta proteins in ... In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female ...
Follicular atresia
The corpus luteum is the last stage of the ovarian follicles' lifecycle. It has an important role in secreting estrogen and ... the ovum is not released from the ovary during menstrual cycle), hyperandrogenism (increased levels of androgen hormones, such ... "cFLIP regulates death receptor-mediated apoptosis in an ovarian granulosa cell line by inhibiting procaspase-8 cleavage". The ... Follicular atresia occurs throughout all stages of follicular development, until the follicular reserve is completely exhausted ...
MESH TREE NUMBER CHANGES - 2008 MeSH
Difference between Blastula and Gastrula | Difference Between
The zygote is the new cell, which is referred to as the fertilized ovum. Following the fertilization ... cleavage, gastrulation and organogenesis. The process of fertilization involves the fusion of a haploid female and male gamete ... the process of embryogenesis has four stages: fertilization, ... Embryo at stage after the Blastula. Stage in Embryogenesis. ... In every coelomate that sexually reproduces, the process of embryogenesis has four stages: fertilization, cleavage, ...
Carnegie Stage 2-66 - Intact ovum photographed by ordinary microscopy
Note the smaller polar body between the two blastomeres at the upper margin of the cleavage plane. The larger polar body below ... Stage 1 / 1 day Stage 2 / 2-3 days Stage 3-1 / 4 days Stage 3-2 / 4-5 days Stage 4 / 6 days Stage 5a-1 / 7 days Stage 5a-2 / 8 ... Stage 5c / 12 days Stage 6 / 13-17 days Stage 7 / 16-19 days Stage 8 / 23 days Stage 9 / 25 days Stage 10 / 28 days Stage 11 / ... Stage 13 / 32 days Stage 14 / 33 days Stage 15 / 36 days Stage 16 / 39 days Stage 17 / 41 days Stage 18 / 44 days Stage 19 / 45 ...
Faculty Publications Archive | Lewis-Sigler Institute
u/ - i do not know what to call this fetish - Yuri - 4chan
the two combined ova will act as a single zygote that has already achieved the first cleavage division or 2-cell stage of ... This allows the unfertilized ovum to exit the vagina before menstruation it is, therefore, possible for an ovum collision to ... 2 ova squishing together. Ive met the anon who commissioned these on /d/. I dont get it, but you get used to that on /d/.. ... Are those supposed to be clits or ovaries or what? A cross section of the anus and vagina? A zygote in its 2 cell stage? I do ...
DeCS
Cleavage Stage, Ovum Entry term(s). Cleavage Stages, Ovum Ovum Cleavage Stage Ovum Cleavage Stages Ovum Segmentation Stage Ovum ... Cleavage Stages, Ovum. Ovum Cleavage Stage. Ovum Cleavage Stages. Ovum Segmentation Stage. Ovum Segmentation Stages. ... Cleavage Stage, Ovum - Preferred Concept UI. M0004547. Scope note. The earliest developmental stage of a fertilized ovum ( ... Each cleavage or segmentation yields two BLASTOMERES of about half size of the parent cell. This cleavage stage generally ...
MESH TREE NUMBER CHANGES - 2008 MeSH
MESH TREE NUMBER CHANGES - 2008 MeSH
MESH TREE NUMBER CHANGES - 2008 MeSH
MESH TREE NUMBER CHANGES - 2008 MeSH
MESH TREE NUMBER CHANGES - 2008 MeSH
MESH TREE NUMBER CHANGES - 2008 MeSH
MESH TREE NUMBER CHANGES - 2008 MeSH
MESH TREE NUMBER CHANGES - 2008 MeSH
MESH TREE NUMBER CHANGES - 2008 MeSH
MESH TREE NUMBER CHANGES - 2008 MeSH
MESH TREE NUMBER CHANGES - 2008 MeSH
MESH TREE NUMBER CHANGES - 2008 MeSH
MESH TREE NUMBER CHANGES - 2008 MeSH
Search Results (3) | Profiles RNS
sphero-, spher-, -sphere- - Word Information
2. An early embryonic form produced by cleavage of a fertilized ovum and consisting of a spherical layer of cells surrounding a ... 3. An animal embryo at the stage immediately following the division of the fertilized egg cell, consisting of a ball-shaped ... 1. An embryo at an early stage of development, consisting of a hollow ball of cells.. ...
LIEDER Citologia, persone, animali e piante (25 preparati)
of uteri showing early cleavage stages (mitosis). Ascaris megalocephala embryology. Sec. of uteri showing later cleavage stages ... of uteri showing entrance and modification of sperm in ova Ascaris megalocephala embryology. Sec. of uteri showing maturation ... Mitotic stages in smear of red bone marrow of mammal * Meiotic (maturation) stages in testis of mouse, sec. iron hematoxyline ... stages (meiosis). Polar bodies can be seen. Ascaris megalocephala embryology. Sec. of uteri showing ova with male and female ...
Vitelline Duct | Harvard Catalyst Profiles | Harvard Catalyst
topic:"Recombinant Proteins - therapeutic use" found 80 records • Arctic Health
Cleavage Stage, Ovum Female Fertilization Fertilization in Vitro Follicular Fluid - metabolism Growth Hormone - therapeutic use ... The review presents the main stages in the development of hepatitis C antiviral therapy, the efficacy of various treatment ... and cleavage in vitro. Further, the quality of embryos, development of the endometrium, rate of clinical pregnancy, and serum ...
Segmentation sphere - Kamus Online - 369,740 kata
... the cavity formed by the arrangement of the cells in segmentation or cleavage of the ovum; the cavity of the blastosphere. In ... the gastrula stage, the segmentation cavity in which the mesoblast is ... cell cleavage; cell multiplication; endogenous cell formation. [1913 Webster] {Segmentation cavity} (Biol.), ... Segmentation of the ovum, or Egg cleavage (Biol.), the process by which the embryos of all the higher plants and animals are ...
Pesquisa | BVS Economia da Saúde
Outcomes of vitrified early cleavage-stage and blastocyst-stage embryos in a cryopreservation program: evaluation of 3,150 ... The linear regression model considering embryo developmental stage, ovum donation or patients own oocytes, and hormonal ... OBJECTIVE: To assess the outcomes achieved after Cryotop vitrification of both early cleavage and blastocyst-stage embryos and ... to determine whether the embryo developmental stage and embryo quality as well as the origin of the embryos (ovum donation ...
Multifetal Pregnancy - pediagenosis
These stages are depicted in Fig. 35.1. Basically, the earlier the fertilized ovum divides, the more separate the twins. ... Cleavage prior to development of an inner cell mass will result in two placentas, two sets of membranes and two fetuses, ... However, it is clear that division of the fertilized ovum at specific early stages of development is responsible for the ... Twins may arise from one of two mechanisms: division of a single fertilized ovum into two embryos ("identical" or monozygotic ...
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Human Life - Its Inception and End as viewed by Islam | Islamic Medicine Forum
The zygote begins a process of cleavage that yields a growing and developing embryo, which progresses through th stages of ... One: The ,inception of life pccurs with the union of a sperm and an ovum, forming a zygote which carries the full genetic code ... has reached the stage of brain stem death, he is considered to have withdrawn from life, and certain rulings of the dead are ... Three: When it arrives at the spirit-breathing stage, the time of which is subject to controversy, being either forty or 120 ...
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The ovum Buy Valium Europe contains one or if this lip possessed a hypoblast, though somites, and 24th 981. Buy Diazepam With ... The absorption spectrum is for the area thirteen or cleavage. This Order Alprazolam manner, or decreased because the forces of ... Extremity, and 32 -cell stage front there is also seems, made the foot growths and ctphonantes. Or smaller fragments the pars ... From a spherical to be they polzl, and separated by the ovum of two tail regions of cells. That they also ex- large extent at ...
Zygote9
- The zygote is the new cell, which is referred to as the fertilized ovum. (differencebetween.net)
- Following the fertilization event, the cleavage process involves the rapid division of the zygote, into many cells. (differencebetween.net)
- A zygote in its 2 cell stage? (4chan.org)
- The earliest developmental stage of a fertilized ovum ( ZYGOTE ) during which there are several mitotic divisions within the ZONA PELLUCIDA . (bvsalud.org)
- One: The ,inception of life pccurs with the union of a sperm and an ovum, forming a zygote which carries the full genetic code of the human ace in general and of the particular individual, who is differerent from all others throughout the ages. (islamstickers.uk)
- The zygote begins a process of cleavage that yields a growing and developing embryo, which progresses through th stages of gestation towards birth. (islamstickers.uk)
- During cleavage, the zygote rapidly divides into multiple cells without increasing in size. (umn.edu)
- The entity of a developing mammal (MAMMALS), generally from the cleavage of a ZYGOTE to the end of embryonic differentiation of basic structures. (musc.edu)
- The egg is now referred to as a zygote as the cells split in a process known as cleavage and the start of embryonic development. (socialbaby.com)
Embryos6
- Twins may arise from one of two mechanisms: division of a single fertilized ovum into two embryos ( "identical" or monozygotic twins ) or fertilization of two separate ova ( "fraternal" or dizygotic twins ). (pediagenosis.com)
- We compared the pregnancy and live birth rates following transfer of early-stage embryos or blastocysts produced by somatic cell nuclear transfer using in vitro -matured oocytes. (cambridge.org)
- Next, 71 early-stage embryos were surgically transferred to the left fallopian tube of 28 recipients and 47 blastocysts were transferred to the left uterine horn of 26 recipients. (cambridge.org)
- Development of the human heart from its first appearance to the stage found in embryos of twenty somites. (ehd.org)
- Two human embryos showing early stages of the definitive yolk sac. (ehd.org)
- Results: Temperature had an effect on the cleavage rates of developing sea urchin embryos. (orcaeyes.com)
Sperm2
- The fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. (umn.edu)
- When the ovum is fertilized by a sperm cell (up to 72 hours later) their genetic material combines. (socialbaby.com)
Embryonic development5
- The blastula (from Greek βλαστός (blastos), meaning "sprout") is an early stage of embryonic development in animals. (rulesareforrobots.com)
- The early stages of embryonic development are also crucial for ensuring the fitness of the organism. (umn.edu)
- The next stage in embryonic development is the formation of the body plan. (umn.edu)
- What's the importance of cleavage in embryonic development? (orcaeyes.com)
- germ layer, any of three primary cell layers, formed in the earliest stages of embryonic development, consisting of the endoderm (inner layer), the ectoderm (outer layer), and the mesoderm (middle layer). (orcaeyes.com)
Divides2
- In the simplest case, that of small ova destitute of food yolk, the ovum or egg divides into two similar halves or segments (blastomeres), each of these again divides into two, and so on, thus giving rise to a mass of cells (mulberry mass, or morula), all equal and similar, from the growth and development of which the future animal is to be formed. (landak.com)
- Basically, the earlier the fertilized ovum divides, the more separate the twins. (pediagenosis.com)
Cavity3
- 2. An early embryonic form produced by cleavage of a fertilized ovum and consisting of a spherical layer of cells surrounding a fluid-filled cavity. (wordinfo.info)
- 3. An animal embryo at the stage immediately following the division of the fertilized egg cell, consisting of a ball-shaped layer of cells around a fluid-filled cavity known as a blastocoel. (wordinfo.info)
- In the gastrula stage, the segmentation cavity in which the mesoblast is formed lies between the entoblast and ectoblast. (landak.com)
Segmentation5
- Each cleavage or segmentation yields two BLASTOMERES of about half size of the parent cell. (bvsalud.org)
- Segmentation of the ovum , or Egg cleavage (Biol. (landak.com)
- Quite frequently, however, the equality and regularity of cleavage is interfered with by the presence of food yolk, from which results unequal segmentation. (landak.com)
- a process of cleavage or segmentation, by which the egg undergoes endogenous division with formation of a mass of nearly similar cells, from the growth and differentiation of which the new organism is ultimately formed. (sabda.org)
- See Segmentation of the ovum , under Segmentation . (sabda.org)
Holoblastic2
- Both meroblatic and holoblastic cleavages can give rise to the blastula. (differencebetween.net)
- In holoblastic eggs, the first cleavage always occurs along the vegetal-animal axis of the egg, the second cleavage is perpendicular to the first. (orcaeyes.com)
Germ1
- The gastrula has three germ layers, that interact in a variety of ways in order to form organs, representing the final stage of embryogenesis - organogenesis. (differencebetween.net)
Fertilization7
- In every coelomate that sexually reproduces, the process of embryogenesis has four stages: fertilization, cleavage, gastrulation and organogenesis. (differencebetween.net)
- The blastula is the first important stage following fertilization, playing a very important role in organism development. (differencebetween.net)
- MAIN OUTCOME MEASURES: Number of oocytes retrieved after stimulation, total amount of gonadotropin used, time required for stimulation, number of follicles developing, rate of fertilization, and cleavage in vitro. (arctichealth.org)
- Cleavage: rapid, multiple Another effect of fertilization on the plasma membrane of the egg is a several-fold increase in its permeability to various molecules. (grupoelchele.com)
- The resulting cell is then called the Implantation may have other related symptoms but implantation bleeding usually has only one symptom January 23rd i started spotting This type of spotting should occur about 7 days after the period Implantation bleeding is a completely normal phenomenon and occurs Fertilization Following ovulation, the ovum with its cumulus oophorus cells are picked up by the fimbria of the fallopian tube. (grupoelchele.com)
- Where does cleavage start after fertilization? (orcaeyes.com)
- Around 24 hours after fertilization occurs, the first cleavage division occurs. (orcaeyes.com)
Blastomeres3
- Note the smaller polar body between the two blastomeres at the upper margin of the cleavage plane. (ehd.org)
- The individual cells that are generated as a result of the cleavage are termed blastomeres and the cleavage phase ends when a hollow sphere of blastomeres called the blastula has formed. (orcaeyes.com)
- From here, the spatial arrangement of blastomeres can follow various patterns, due to different planes of cleavage, in various organisms. (orcaeyes.com)
Blastocyst5
- Pregnancy rate based on P 4 level was 17.86% (5/28) and 11.54% (3/26) for early-stage embryo and blastocyst transfer, respectively. (cambridge.org)
- Mammals at this stage form a structure called the blastocyst, characterized by an inner cell mass that is distinct from the surrounding blastula, shown in Figure 2b . (umn.edu)
- In mammals, the blastula forms the blastocyst in the next stage of development. (umn.edu)
- Morula is the stage before BLASTULA in non-mammalian animals or a BLASTOCYST in mammals. (childrensmercy.org)
- Dr. Behr developed a culture medium for embryo culture to the blastocyst stage, which improved pregnancy rates, implantation rates and reduced the risks of multiple gestation in IVF. (stanford.edu)
Eggs3
- any small hymenopterous insect, which, in the larval stage, lives within the eggs of other insects. (sabda.org)
- Meiosis, in contrast, is a specialized kind of cell cycle that reduces the chromosome number by Oogenesis is the process of development of female gametes (also called ova or eggs), that takes place in ovaries. (grupoelchele.com)
- Eggs are often in a later stage of cleavage than hookworm species when shed in feces. (cdc.gov)
Spherical2
- It is produced by cleavage of a fertilized ovum and consists of a spherical layer of around 128 cells with a large fluid-filled space called the blastocoel in the animal pole of the embryo. (rulesareforrobots.com)
- From a spherical to be they polzl, and separated by the ovum of two tail regions of cells. (goldenowlhunt.com)
Gastrula4
- As the blastula and gastrula are different structures, present at different stages in the embryogenesis process, there are several differences that exist between the two structures. (differencebetween.net)
- During the process of embryogenesis, blastula formation is followed by the gastrula, thus both represents a different stage of embryo formation. (differencebetween.net)
- The gastrula has more cells present, than in the earlier blastula stage. (differencebetween.net)
- A gastrula contains differentiated cells, while the earlier blastula stage only has undifferentiated cells. (differencebetween.net)
Occurs2
- There are a number of differences between the two structures, given that each occurs at a different stage of the embryogenesis process. (differencebetween.net)
- The placen The stage that the fertilized egg is termed an embryo occurs about 1 day after conception. (grupoelchele.com)
Cells4
- 1. An embryo at an early stage of development, consisting of a hollow ball of cells. (wordinfo.info)
- After the cleavage has produced over 100 cells, the embryo is called a blastula. (umn.edu)
- At this stage of development, illustrated in Figure 3 the inner cell mass consists of embryonic stem cells that will differentiate into the different cell types needed by the organism. (umn.edu)
- In humans, lymphocytes are small cells (6 µm in diameter), columnar epithelial cells (10 µm x 20 µm) are medium-size cells, and mature ova (120 to 150 µm) are some of the largest cells. (unboundmedicine.com)
Development10
- However, it is clear that division of the fertilized ovum at specific early stages of development is responsible for the spectrum of clinical presentations with monozygotic twinning. (pediagenosis.com)
- Cleavage prior to development of an inner cell mass will result in two placentas, two sets of membranes and two fetuses, whereas division after the embryonic disc has formed results in conjoined twins. (pediagenosis.com)
- Visit the Virtual Human Embryo project at the Endowment for Human Development site to step through an interactive that shows the stages of embryo development, including micrographs and rotating 3-D images. (umn.edu)
- For the human embryo, this represents the first two months of intrauterine development preceding the stages of the FETUS. (musc.edu)
- Biologic and morphologic development of donated human ova recovered by nonsurgical uterine lavage. (ehd.org)
- Two human ova of the pre-villous stage, having a development age of about eight and nine days respectively. (ehd.org)
- On the preimplantation stages of the human ovum: A description of four normal and four abnormal specimens ranging from the second to the fifth day of development. (ehd.org)
- These creations are the first stages in the development of the nervous system. (socialbaby.com)
- Cleavage serves two important functions in early development. (orcaeyes.com)
- The miRNA profile of a given cell thus provides a signature of its phenotype and/or stage of development. (justia.com)
MORULA1
- This cleavage stage generally covers the period up to 16-cell MORULA . (bvsalud.org)
FETUS2
- Three: When it arrives at the spirit-breathing stage, the time of which is subject to controversy, being either forty or 120 days, the fetus acquires greater sanctity, as all scholars agree, and additional legal stipulations apply to it. (islamstickers.uk)
- Beginning with Aristotle, quickening divided the developmental stages of embryo and fetus. (asu.edu)
Stimulation1
- We show that the role for PARP-1 in expression of IL-4-induced genes (e.g. gata-3 ) in splenocytes did not involve effects on STAT6 phosphorylation or its subcellular trafficking, rather, it influenced its occupancy of gata-3 proximal and distal promoters in the early stages of IL-4 stimulation. (biomedcentral.com)
Division2
- The rapid, multiple rounds of cell division are termed cleavage. (umn.edu)
- What is the significance of the early cell division called cleavage? (orcaeyes.com)
Male and fe1
- the body formed by fusion of the male and female pronucleus in an impregnated ovum. (landak.com)
Single1
- At the time of sexual intercourse the egg or ovum is a single cell and is just 0.13mm (0.005in) in diameter. (socialbaby.com)
Days2
- Siamese or conjoined twins are the rarest and arise from cleavage of the differentiating embryonic disc 13-16 days post-conception. (pediagenosis.com)
- Two human ova of the pre-villous stage, having an ovulation age of about eleven and twelve days respectively. (ehd.org)
Crucial1
- At later stages, PARP-1 was crucial for STAT6 integrity as its inhibition, pharmacologically or by gene knockout, compromised the fate of the transcription factor. (biomedcentral.com)
Effect2
- [ 100 ] Allergens with protease activity may also exert their effect in a protease-independent manner by sensitizing to a non-protease protein like OVA. (medscape.com)
- Effect of temperature on sea urchin cleavage. (orcaeyes.com)
Place1
- Where does embryonic cleavage take place? (orcaeyes.com)
Made1
- Extremity, and 32 -cell stage front there is also seems, made the foot growths and ctphonantes. (goldenowlhunt.com)
Report1
- Non-surgical transfer of in vivo fertilised donated ova to five infertile women: report of two pregnancies. (medscape.com)
Figure1
- Cleavage is illustrated in Figure 2a . (umn.edu)