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At least 19 recordsLinked to original sources
PubMed1991

Effect of exogenous corticosterone on chicken embryonic development.

Embryonic corticosterone (CS) levels were altered by dipping 3-day-old fertile Leghorn eggs in 0, .01, .05, and 1% CS dissolved in absolute ethanol. Mortality was determined by candling from Day 4 through hatch. Body weights and serum CS were measured daily from Day 14 until hatch. Embryos of eggs dipped in 1% CS in ethanol solution had reduced circulating CS. Embryo weights were reduced and mortality increased as concentration of hormone increased. A CS peak was observed just before hatch for control, .01 and .05% groups, but not for the .1% group. All embryos in the .1% treatment group died before hatch. The importance of embryonic CS for normal development and hatching was indicated.

Animals↗
PubMed1991

Distribution and expression of two interactive extracellular matrix proteins, cytotactin and cytotactin-binding proteoglycan, during development of Xenopus laevis. I. Embryonic development.

An immunohistochemical study of the localization of cytotactin and cytotactin-binding (CTB) proteoglycan throughout embryonic development of the anuran Xenopus laevis reveals that both appear in a restricted pattern related to specific morphogenetic events. CTB proteoglycan expression is first detected during gastrulation at the blastopore lip. Later, it is seen in the archenteron roof around groups of cells forming the notochord, somites and neural plate. Cytotactin first appears after neurulation, and is restricted to the intersomitic regions. Both molecules appear along the migratory pathways of neural crest cells in the trunk and tail. Later, cytotactin is present at sites where neural crest cells differentiate, around the aorta and in the smooth muscle coat of the gut; CTB proteoglycan is absent from these sites. In the head, cytotactin is initially restricted to the regions between cranial somites, while CTB proteoglycan is distributed throughout the cranial mesenchyme. The expression of both molecules is later associated with key events in chondrogenesis during the development of the skull. After chondrogenesis, CTB proteoglycan is distributed throughout the cartilage matrix, while cytotactin is restricted to a thin perichondrial deposit. Both molecules are expressed in developing brain. These findings are compared to studies of the chick embryo and although distinct anatomical differences exist between frog and chick, the expression of these molecules is associated with similar developmental processes in both species. These include mesoderm segmentation, neural crest cell migration and differentiation, cartilage development, and central nervous system histogenesis.

Animals↗
PubMed1992

Effects of three methods of selection for litter size in mice on pre-implantation embryonic development.

Characteristics of preimplantation embryonic development to Day 3.5 of gestation were evaluated in lines of mice after 21 generations of selection for litter size or components of litter size. Selection criteria were direct selection for number born (LS), selection on an index of ovulation rate and the proportion of ova shed that resulted in fully formed pups (IX), selection for number born in unilaterally ovariectomized females as an indication of uterine capacity (UT), and an unselected control (LC). Comparison of the average distributions of embryonic stage of development on the left side of the uterus showed that selection (average effect of LS, IX, and UT vs. LC) tended to advance (p = 0.07) the average stage of embryonic development at Day 3.5 and shift the distribution (p = 0.10) by increasing the frequency of expanded blastocysts and decreasing the frequency of pre-morula embryos. A similar shift in the distribution on the right side of the uterus was not statistically significant. Selection decreased (p = 0.06) variability in developmental stage among embryos within the right uterine horn. These selection criteria evaluated in the mouse appear to have changed the frequencies of genes that affect some determinants of average stage of embryonic development and uniformity of development within a uterine horn at Day 3.5 of gestation.

Animals↗
PubMed1979

The biosynthesis of nicotinamide adenine dinucleotide during early stages of frog embryonic development of haploid and diploid embryos.

1. Concentration of NAD during embryonic development of haploid and diploid embryos of frog was followed. NAD content in haploid embryonic forms is twice that in diploid embryos. 2. The variation of the NMN adenylyltransferase activity in the oocytes and during the first states of embryonic development as surveyed in the nuclear soluble fraction and the nuclear insoluble fraction (chromatin). 3. The enzyme activity in the soluble fraction is low during embryonic development and shows higher values in haploid embryos. 4. In the nonfertilized mature oocytes, the NMN adenylyltransferase activity is sixfold higher in the insoluble chromatin fraction than in the soluble fraction. 5. The evolution of the NMN adenylyltransferase in the insoluble chromatin fraction also shows higher values in haploid embryos, as compared with diploid forms.

Animals↗
PubMed1991

Tissue-dependent regulation of protein tyrosine kinase activity during embryonic development.

Protein tyrosine kinase activity was assayed in a variety of chicken tissues during embryonic development and in the adult. In some tissues protein tyrosine kinase activity decreased during embryonic development; however, in other tissues it remained high throughout development, it contrast to the level of protein tyrosine phosphorylation, which decreased during development. The highest levels of tyrosine kinase activity were detected in 17-d embryonic brain although only low levels of protein tyrosine phosphorylation were observed in this tissue. Several alternatives were examined in an effort to determine the mechanism responsible for the low levels of tyrosine phosphorylated proteins in most older embryonic and adult chicken tissues despite the presence of highly active tyrosine kinases. The results show that the regulation of protein tyrosine phosphorylation during embryonic development is complex and varies from tissue to tissue. Furthermore, the results suggest that protein tyrosine phosphatases play an important role in regulating the level of phosphotyrosine in proteins of many older embryonic and adult tissues.

Animals↗
PubMed1975

A rapid spectrophotometric method for the monitoring of embryonic development in ticks (Acarina: Ixodoidea).

A rapid spectrophotometric method for the monitoring of embryonic development in Boophilus decoloratus (Koch, 1844) is described. The method is based on a quantitative assessment of guanine, the prinicipal end-product of nitrogenous metabolism in ticks, which is gradually built up and stored in the rectal sac during embryonic development of the larvae. A study of the growth of tick embryos under constant temperature conditions and 6 different humidity conditions demonstrated that embryonic development was dependent on the water content of the eggs at the time of oviposition. When eggs lost more than 35% of their initial mass through evaporation, nitrogenous metabolism (as indicated by guanine production) was seriously affected and embryos died.

Animals↗
PubMed1992

Insulin and insulinlike growth factors in embryonic development. Effects of a biologically inert insulin (guinea pig) on rat embryonic growth and development in vitro.

Congenital anomalies occur up to four times more frequently in diabetic pregnancy than in the nondiabetic population. Although past work has shown that maternal hyperglycemia and hyperketonemia may increase embryonic abnormalities, recent experimental evidence suggests that low insulin levels may also contribute to diabetic embryopathy. This study investigated the effects of guinea pig serum (whose insulin is inactive in rat systems) on rat embryonic growth and development in culture. Supplementation of guinea pig serum with pork insulin at low (1 ng/ml) and high (5 ng/ml) physiological concentrations and insulinlike growth factors (IGF) I and II were also studied. Culture of rat embryos from the early headfold stage in guinea pig serum resulted in poor embryonic growth and development with a 92% rate of anomalies. Supplementation of guinea pig serum with zinc-binding pork insulin significantly improved rat embryonic growth and development (46% anomaly rate) especially between the first 5 and 21 h of the period of organogenesis. This evidence supports our most recent findings that low insulin levels, as encountered in untreated diabetic pregnancy, may contribute to the increased risk of congenital abnormality. Insulin at low physiological concentrations improved growth, whereas higher physiological concentrations were required to increase growth and development. IGF-I or IGF-II supplementation improved rat embryonic growth and development but failed to match that of the controls, indicating that other growth factors including insulin may also be required.

Abnormalities, Drug-Induced↗
PubMed1979

Evidence that sclerotomal cells do not migrate medially during normal embryonic development of the rat.

During embryonic development the medial part of the somite disorganizes or breaks up into sclerotomal cells which, according to many published reports, migrate medially to surround the notochord. The purpose of the study was to determine whether these cells actually migrate medially toward the notochord. Distances were measured between the notochord and the adjacent neural tube and the somite or its remnant during the period of somite disorganization. Serially sectioned, normal 10.5- to 13.5-day (d) rat embryos were used. Only transverse sections through the middle of the fourth cervical (C-4) body segment were measured, corresponding to the level of somite No. 8 (10.5 d) or its dermatomyotome remnant (10.5-11.5d) or spinal nerve C-4 (12.5-13.5d). Measurements were taken at six stages from photographic montages, all of which were made at precisely the same magnification. The notochord was the central axial structure from which the measurements were determined. The changes in distance show that during the period of somite breakup the neural tube grows dorsally, away from the notochord which lies adjacent to its ventral surface. Simultaneously the somite remnant moves laterally and dorsally, all the while maintaining its position relative to the overlying ectoderm and leaving behind a trail of sclerotomal cells. Also at each stage cell counts were made on the medial sclerotomal region of the C-4 segment. The average counts reveal that not only does the total number of cells increase substantially over the three-day period (42-7,546), but also the total number of mitoses (3.5-200), while the mitotic index decreases (9.0-2.7). High proliferative activity is apparent in the medial sclerotomal cells throughout the 3-day period. The evidence supports the conclusion that local proliferation of the trailing cells, which were left by the somite remnant as it moved dorsolaterally, causes the subsequent increase in density of the perichordal tissue, rather than an influx of migrating cells. Instead of sclerotomal cells migrating medially toward the notochord, the present study suggests that these cells retain their position relative to the notochord or central axis and that the medial sclerotomal region forms as a result of the growth movements of the surrounding structures.

Animals↗
PubMed1991

Antibodies to sperm surface antigens and the c-myc proto-oncogene product inhibit early embryonic development in mice.

The effects of antibodies against sperm antigens and the c-myc proto-oncogene product on early embryonic development were investigated in mice. Affinity-purified Fab' antibodies against lithium diiodosalicylate (LIS)-solubilized murine sperm extract and fertilization antigen (FA-1) reduced (p less than 0.01 to p less than 0.001) blastulation rates of in vitro cultured 2-cell murine embryos primarily because of an arrest of development at the morula stage. Similarly, the c-myc monoclonal antibody (mAb) affected early embryonic development in a dose-dependent manner. These effects were specific, since immunoabsorption, with its respective peptide, completely blocked the inhibitory effect of the c-myc mAb. Anti-LIS sperm Fab' identified four protein bands (approx. 36, 29, 24.6, and 17.6 kDa) on Western blots of extracts from unfertilized and fertilized ova, one band (approx. 68 kDa) each on 4-8-cell embryo and morula extracts, and one band (approx. 53 kDa) on blastocyst extracts. Anti-FA-1 Fab' did not react with unfertilized or fertilized ova, but specifically identified two protein bands (approx. 53 and 25.7 kDa) on blots of 2-cell-embryo extract, one band (approx. 25.7 kDa) on morula extract, and one band (approx. 53 kDa) on blastocyst extract. The c-myc mAb did not react with any band corresponding to the c-myc protein on blots of extracts from unfertilized or fertilized ova, 2-cell embryos, 4-8-cell embryos, morulae, or blastocysts. These results suggest that some of the cross-reacting sperm antigens that are expressed during early cleavages, and the product of the c-myc proto-oncogene may have a role in normal early embryonic development.

Animals↗
PubMed2025

Exposure to zinc oxide nanoparticles inhibits preimplantation embryonic development by disrupting zygotic genome activation.

The potential adverse effects of zinc oxide nanoparticles (ZnONPs) on human reproductive health may arise from their increasing industrial and commercial applications. However, their effects on preimplantation embryonic development and the related molecular mechanisms are still not well understood. Here, we demonstrate that ZnONPs exposure exhibit toxicity to a critical developmental period in mice. We observed that sustained exposure to ZnONPs in vitro resulted in embryonic development arrest at the 2-cell stage. To identify the susceptible stage, we controlled experiments to treat embryos with ZnONPs in the different processes of early embryonic development and determined that ZnONPs mainly to affect 2-cell stage embryos. According to the RNA-seq and EU (5-ethynyl uridine) analysis, the transcriptional activity of minor ZGA genes increased in the late 2-cell embryos following ZnONPs exposure. Subsequently, we employed multi-omics assays, including CUT&Tag and ATAC-seq. We found that ZnONPs exposure led to increased enrichment of H3K27ac (Histone H3 acetylated lysine 27) in late 2-cell embryos and enhanced chromatin accessibility, which led to abnormal upregulation of minor zygotic genome activation (ZGA) genes. In addition, the direct occupancy of ZnONPs at H3K27ac modification sites was verified through pulldown and immunoprecipitation. In conclusion, our findings demonstrate that ZnONPs exposure disrupting minor ZGA by interfering with H3K27ac erasure on the embryonic genome and ultimately impairing the developmental potential of embryos.

Animals↗
PubMed1979

Effects of fever and hyperthermia on the embryonic development of rabbits.

The effects of viral induced fever and environmental hyperthermia on embryonic development in pregnant rabbits are described. Embryonic development was not disturbed following fever, but there were anomalies in development following hyperthermia. Possible explanations for the different effects of hyperthermia and fever are discussed.

Animals↗
PubMed1992

Modulation of swimming rhythmicity by 5-hydroxytryptamine during post-embryonic development in Xenopus laevis.

During the first 24 h of post-embryonic development in Xenopus laevis, a rapid change in the neural activity underlying swimming occurs in which the duration of ventral root discharge on each cycle increases from a single compound impulse to discrete bursts of activity. Moreover, this change in motor output progresses rostrocaudally, suggesting that it could result from the influence of a descending neural pathway upon the spinal rhythm-generating circuitry during early post-embryonic development. To begin to examine whether serotonergic neurons of brainstem raphe nuclei might have a role in this swimming development, we have studied the effects of 5-hydroxytryptamine (5HT) on fictive swimming in embryonic and larval animals. As previously demonstrated for other vertebrate locomotor rhythms, we find that bath-applied 5HT enhances the duration of motor activity on each cycle of larval fictive swimming. In addition, our results show that the sensitivity of the swimming rhythm to exogenous 5HT follows a strict rostrocaudal gradient. In young embryos (stages 32-36) 5HT does not affect the duration of ventral root impulses per cycle; by the time of hatching (stage 37/38), rostral but not caudal discharge is enhanced, and by stage 42 (24 h post-hatching) 5HT can increase motor burst durations along most of the length of the animal. These reversible changes induced by bath-applied 5HT closely resemble the normal rostrocaudal development of burst discharge during swimming in animals some 12 h older.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Expression of mRNA for activin-binding protein (follistatin) during early embryonic development of Xenopus laevis.

Follistatin is a specific activin-binding protein and is supposed to control activin functions. During Xenopus embryonic development, activin is thought to act as a natural mesoderm-inducing factor. We isolated here the Xenopus follistatin cDNA from Xenopus ovary cDNA library and studied the expression of Xenopus follistatin gene during the course of early embryonic development. The Xenopus follistatin has an 84% homology at the level of deduced amino acid sequence with human and porcine follistatin. Its 3.5 kb mRNA is first expressed at the gastrula stage, when the expression of activin mRNA becomes first detectable, and increased thereafter. Another species of 2 kb mRNA become detectable from early neurula and also increased dramatically in tadpole. These results suggest that the follistatin acts also as a regulator of activin in inductive interactions during amphibian embryonic development.

Amino Acid Sequence↗
PubMed1992

Research note: variability in preincubation embryonic development in domestic fowl. 2. Effects of duration of egg storage period.

Embryos of eggs from Single Comb White Leghorn hens were analyzed to determine whether duration of egg storage significantly affects embryonic development prior to incubation. Eggs were gathered over a period of 5 days from 25-wk-old hens that were naturally inseminated and housed in floor pens. Within 1 h of oviposition the eggs were collected and assigned randomly to one of five storage treatment groups of 0, 4, 7, 14, or 21 days. Fresh egg weight was recorded and the eggs were placed on plastic egg flats and stored at 14 C. Weight of each egg was measured after storage to determine amount of weight lost during storage. A total of 500 embryos were examined after storage. Viable embryos were staged for development using a modified Eyal-Giladi and Kochav classification. The incidence of embryonic mortality was noted. Duration of storage (P = .5815) collection date (P = .5815), and fresh egg weight (P = .3789) did not affect embryonic development significantly. A significant linear relationship was observed between duration of the storage period and loss of egg weight (P = .0001). Embryonic mortality was significantly related to loss of egg weight (P = .0001). Mortality was highest in eggs that were stored for a longer period of time. The data from the current study indicate that storing fertile eggs below physiological zero inhibits embryonic development. One of the reasons for the increased incidence of embryonic mortality in eggs that were stored for longer periods may be related to the increased egg weight loss in these eggs.

Animals↗
PubMed2025

EZH2 variants derived from cryptic splice sites govern distinct epigenetic patterns during embryonic development.

EZH2 catalyzes H3K27me3 and is essential for embryonic development. Although multiple EZH2 variants have been identified, the functional implications and physiological significance of its heterogeneity remain unclear. Here, we revealed that conserved cryptic splice sites generated two EZH2 variants with (EZH2A) or without (EZH2B) a 27-nt region, coding for a 9-aa segment. Structural modeling showed that splice-in or splice-off of the 9-aa segment caused a topological change in EZH2 structure. The 9-aa surplus in EZH2A strengthened its interaction with other PRC2 components, particularly in PRC2.2 holocomplex. We developed point-mutation mouse lines specifically depleting EZH2A or EZH2B (Ezh2amut or Ezh2bmut). Biallelic deletion of Ezh2a caused developmental defects and embryonic lethality between E12.5 and E15.5, while the Ezh2bmut mice were fertile and developed normally. Combined RNA-seq and CUT&Tag analyses in mouse embryonic fibroblasts revealed that EZH2A and EZH2B bound to different genomic loci and affected H3K27me3 deposition in different subsets of genes related to development or the innate immune system, respectively. EZH2A depletion specifically suppressed the expression of genes involved in the development-related Hippo-Yap1 pathway, which might be attributable to a compensatory process mediated by JARID2. Our findings demonstrate that EZH2 heterogeneity from the 9-aa splicing event plays a crucial role in development.

Animals↗
PubMed1992

Relationship of hen age and egg sequence position with fertility, hatchability, viability, and preincubation embryonic development in broiler breeders.

Indian River broiler breeder hens (n = 29) were caged individually to investigate whether hen age and egg sequence position were related significantly to the dependent variables fertility, hatchability, viability (hatch of fertile eggs), and preincubation embryonic development. Hens were artificially inseminated once per week. All eggs laid during the period of 31 to 54 wk of age were stored at 16 to 17 C for .5 to 7 days. Time of oviposition records were used to assign eggs to sequence position ("first" or "subsequent"). Eggs laid on odd-numbered weeks were broken open, fertility determined, and embryonic development staged. Eggs laid on even-numbered weeks were sent to a commercial hatchery to assess hatchability. Unhatched eggs were opened to determine fertility and embryonic mortality. In addition, hen weight, number of days since insemination, time of oviposition, and egg weight were recorded to determine their relationship to the dependent variables. Fertility (n = 3,240 eggs) and hatchability (n = 1,653 eggs) were not significantly related to egg sequence position, but were related to hen age (P = .0001 and P = .0002, respectively). Older hens demonstrated lower fertility and hatchability. In contrast, embryo viability (n = 1,487 eggs) and preincubation embryonic development (n = 1,200 eggs) were not significantly related to hen age, but were related to egg sequence position (P = .0026 and P = .0001, respectively). First-of-sequence eggs had lower viability, and embryos of these eggs were more developed than embryos of subsequent eggs. These data indicate that the reduction in chick production observed as the hen ages may be due to the increased incidence of first-of-sequence eggs.

Aging↗
PubMed1979

Ultrastructural study of the embryonic development of the pineal gland of the chicken (Gallus gallus).

The authors studied the embryonic development of the pineal gland of the chicken with the electron microscope. The denomination of 'pinealoblasts' was given to the undifferentiated cells which form the primitive pineal outline. In the wall of the pineal cavities, the follicular and parafollicular zones were distinguished; these are formed by type A and type B pinealocytes, the B type being much more abundant. The degenerated cells are constant in the pineal throughout its embryonic development, but much more abundant in the early phases.

Animals↗