Embryonic Japanese Quail Research Articles

Hepatic Transcriptomic Responses to Ethinylestradiol in Embryonic Japanese Quail and Double-Crested Cormorant.

Understanding species differences in sensitivity to toxicants is a critical issue in ecotoxicology. We recently established that double-crested cormorant (DCCO) embryos are more sensitive than Japanese quail (JQ) to the developmental effects of ethinylestradiol (EE2). We explored how this difference in sensitivity between species is reflected at a transcriptomic level. The EE2 was dissolved in dimethyl sulfoxide and injected into the air cell of eggs prior to incubation at nominal concentrations of 0, 3.33, and 33.3 µg/g egg weight. At midincubation (JQ 9 days; DCCO 16 days), livers were collected from five embryos/treatment group for RNA sequencing. Data were processed and analyzed using EcoOmicsAnalyst and ExpressAnalyst. The EE2 exposure dysregulated 238 and 1,987 genes in JQ and DCCO, respectively, with 78 genes in common between the two species. These included classic biomarkers of estrogen exposure such as vitellogenin and apovitellenin. We also report DCCO-specific dysregulation of Phase I/II enzyme-coding genes and species-specific transcriptional ontogeny of vitellogenin-2. Twelve Kyoto Encyclopedia of Genes and Genomes pathways and two EcoToxModules were dysregulated in common in both species including the peroxisome proliferator-activated receptor (PPAR) signaling pathway and fatty acid metabolism. Similar to previously reported differences at the organismal level, DCCO were more responsive to EE2 exposure than JQ at the gene expression level. Our description of differences in transcriptional responses to EE2 in early life stage birds may contribute to a better understanding of the molecular basis for species differences. Environ Toxicol Chem 2024;43:772-783. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Neuropeptidomic analysis of the embryonic Japanese quail diencephalon

BackgroundEndogenous peptides such as neuropeptides are involved in numerous biological processes in the fully developed brain but very little is known about their role in brain development. Japanese quail is a commonly used bird model for studying sexual dimorphic brain development, especially adult male copulatory behavior in relation to manipulations of the embryonic endocrine system. This study uses a label-free liquid chromatography mass spectrometry approach to analyze the influence of age (embryonic days 12 vs 17), sex and embryonic day 3 ethinylestradiol exposure on the expression of multiple endogenous peptides in the developing diencephalon.ResultsWe identified a total of 65 peptides whereof 38 were sufficiently present in all groups for statistical analysis. Age was the most defining variable in the data and sex had the least impact. Most identified peptides were more highly expressed in embryonic day 17. The top candidates for EE2 exposure and sex effects were neuropeptide K (downregulated by EE2 in males and females), gastrin-releasing peptide (more highly expressed in control and EE2 exposed males) and gonadotropin-inhibiting hormone related protein 2 (more highly expressed in control males and displaying interaction effects between age and sex). We also report a new potential secretogranin-2 derived neuropeptide and previously unknown phosphorylations in the C-terminal flanking protachykinin 1 neuropeptide.ConclusionsThis study is the first larger study on endogenous peptides in the developing brain and implies a previously unknown role for a number of neuropeptides in middle to late avian embryogenesis. It demonstrates the power of label-free liquid chromatography mass spectrometry to analyze the expression of multiple endogenous peptides and the potential to detect new putative peptide candidates in a developmental model.

Plasma 17α-estradiol levels and ovarian interstitial cell structure in embryonic Japanese quail

Plasma concentrations of 17α-estradiol (E2) and left ovarian histology were investigated by light and electron microscopy in female Japanese quail from Day 10 of embryonic development through Day 7, posthatch. Plasma E2 levels remained relatively constant (102 to 140 pg/mL) in the embryo followed by a sharp decrease posthatch (47 to 70 pg/mL). Beginning on Day 10 of incubation, cells in the medullary portion (medullary cell; MC) of the left ovaries exhibited ultrastructural evidence of steroidogenic capability. The MC had numerous lipid droplets in close proximity to the smooth endoplasmic reticulum (SER). Mitochondria were also observed in the vicinity of the lipid droplets and SER. On Days 10 and 12, the cristae of the inner mitochondrial membranes were of a lamellar configuration; the cristae of some mitochondria in MC had a tubular appearance by Day 14. These data document relative ontogenic changes in ovarian morphology and plasma E2 levels during the early developmental period in female Japanese quail. These data further support the role of this steroid in sexual differentiation.

Allantoic fluid electrolytes and urate of embryonic Japanese quail subject to differential water loss

Abstract 1. The composition of allantoic fluid from Japanese quail was measured from days 9 to 14 of incubation. 2. The effect of the inhibitor of urate synthesis, allopurinol, upon weight, electrolytes and urate of allantoic fluid was investigated in eggs subject to different rates of water loss. The composition of plasma and the solid fraction of allantoic fluid was also investigated. 3. During the second half of incubation allantoic fluid water weight decreased, as did pH, and sodium, chloride and bicarbonate concentrations. Fluid urate and potassium concentrations increased, but osmolality was unchanged. 4. Allantoic urate and electrolyte concentrations were greatest, and fluid weight lowest, in eggs subject to high water loss. 5. Allopurinol reduced the total urate of allantoic fluid, and increased osmolality and electrolyte concentrations. Allopurinol had no effect on plasma osmolality. 6. It is concluded that in eggs of high water loss allantoic fluid osmolality was reduced by sequestration of sodi...

Mitogen stimulation affects contractile protein mRNA abundance and translation in embryonic quail myocytes.

In cultures of differentiated, fusion-blocked muscle cells obtained from embryonic Japanese quail (Coturnix coturnix japonica), mitogen stimulation leads to an immediate reduction in the rates of synthesis of skeletal muscle myosin heavy chain (MHC) and alpha-actin. The molecular mechanisms responsible for this downregulation were examined. The cellular abundances of the alpha-actin and MHC mRNAs were affected differently by mitogen stimulation; alpha-actin mRNA abundance declined by an amount which quantitatively accounted for the observed decrease in alpha-actin synthesis, whereas MHC mRNA abundance remained virtually unchanged during the first 6 h following mitogen stimulation, a period during which MHC synthesis declined by more than 70%. MHC mRNA abundance did decline between 6 and 12 h after mitogen stimulation. Downregulation of MHC synthesis therefore involves an initial block in mRNA translation combined with a later loss of MHC mRNA from the cytoplasma, while alpha-actin synthesis is regulated at the level of mRNA abundance. These observations are consistent with the hypothesis that, in addition to transcriptional activation of muscle-specific genes, skeletal muscle differentiation normally involves cell cycle-dependent modulations in cellular factors which control message stability and message translation.

Mitogen stimulation affects contractile protein mRNA abundance and translation in embryonic quail myocytes.

In cultures of differentiated, fusion-blocked muscle cells obtained from embryonic Japanese quail (Coturnix coturnix japonica), mitogen stimulation leads to an immediate reduction in the rates of synthesis of skeletal muscle myosin heavy chain (MHC) and alpha-actin. The molecular mechanisms responsible for this downregulation were examined. The cellular abundances of the alpha-actin and MHC mRNAs were affected differently by mitogen stimulation; alpha-actin mRNA abundance declined by an amount which quantitatively accounted for the observed decrease in alpha-actin synthesis, whereas MHC mRNA abundance remained virtually unchanged during the first 6 h following mitogen stimulation, a period during which MHC synthesis declined by more than 70%. MHC mRNA abundance did decline between 6 and 12 h after mitogen stimulation. Downregulation of MHC synthesis therefore involves an initial block in mRNA translation combined with a later loss of MHC mRNA from the cytoplasma, while alpha-actin synthesis is regulated at the level of mRNA abundance. These observations are consistent with the hypothesis that, in addition to transcriptional activation of muscle-specific genes, skeletal muscle differentiation normally involves cell cycle-dependent modulations in cellular factors which control message stability and message translation.

Urates and allantoic regulation in embryonic Japanese quail, Coturnix coturnix japonica.

During embryonic development, allantoic fluid represents the shifting balance between renal excretion and reabsorption by chorioallantoic membranes. Allantoic contents of Na+, K+, Cl-, urate, pH, and water were followed over days 10-15 of the 16 day incubation. Water volume remained near 0.9 ml until day 13, then declined very rapidly. The pH declined more steadily, from 8 to 5.5. Contents of Na+ and Cl- fell regularly to final values 80-88% below day 10. The K+ content changed differently and nearly doubled by day 13 but returned to day 10 values at the end. Urate content rose until day 13, then fell suddenly to low levels. This was due to the abrupt precipitation of most urate into masses not sampled by our method, so that after day 13, urate was underestimated (probably by 90-96%). Ion binding by urates was low (about 3% of Na+ and Cl-, 10% of K+) and appeared to be nonspecific. The underestimate of urate contents means, however, that in late incubation about one third of allantoic Na+ and 65-70% of K+ and Cl- are bound to precipitated urate and do not appear in balance sheets of allantoic ions. These precipitated ions account for the significant amounts of Na+ and K+ that remain in the allantoic remnant, left in the eggshell after hatching, but whose presence is not predicted by analysis of allantoic fluid.

Maintenance of proliferative capacity during avian myogenesis is independent of fusion-permissive calcium ion concentration

Skeletal muscle differentiation is normally accompanied by the permanent withdrawal of myogenic nuclei from the proliferative cycle. However, embryonic Japanese quail ( Coturnix coturnix japonica) myoblasts which have been prevented from fusing in vitro by the addition of EGTA to the culture medium retain the capacity to re-enter the cell cycle following accumulation of muscle-specific myosin [1]. We have therefore investigated the roles of Ca 2+ and fusion in the withdrawal of myogenic cells from the cell cycle. Using three defined media which differ in Ca 2+ and in the ability to promote fusion, we examined the ability of differentiation-competent myoblasts to resume proliferation with increased time in G1. Under these conditions, there is a periodic variation in the ability of the myoblasts to respond to mitogenic stimulation, irrespective of the medium employed. These results indicate that loss of proliferative capacity during myogenesis is independent of Ca 2+.

Genetic regulation of CFA expression in interspecific avian hybrids and somatic cell hybrids.

Chicken fetal-leukemic antigen (CFA) is an oncodevelopmental antigen present on embryonic and neonatal chicken peripheral red blood cells (RBCs) but is not restricted to fetal stages of development in other avian species. Crosses between white Leghorn chickens and Japanese quail resulted in adult hybrids whose peripheral RBCs were positive for CFA. Of the four CFA determinants normally found in adult quail RBCs, only two were present on quail-chicken hybrid RBCs. Adult quail--chicken hybrid RBCs also possessed on CFA determinant associated with early development in both quail and chicken and one chicken-specific CFA determinant. Evidence is presented for the possible association of CFA-positive adult peripheral RBCs and the level of circulating reticulocytes. Crosses between pheasant and turkey (both with CFA-positive adult RBCs) resulted in hybrid adult RBCs expressing only a portion of the parental CFA determinants. Through the formation of somatic cell hybrids between adult chicken and embryonic Japanese quail RBCs, it was possible to induce the appearance of CFA determinants normally restricted to embryonic chicken RBCs. Approximately 50% of the hybrid cells showed reexpression of CFA, and this induction was both time and temperature dependent. Hybridization between RBCs of adult chicken and those of either adult Japanese quail or adult turkey failed to elicit the reexpression of chicken-specific CFA.

Penetration of melanocytes from embryonic japanese quail peritoneum into associated embryonic avian gonads, grown on chicken chorioallantoic membrane.

After association on chorioallantoic membrane (CAM) of an embryonic bird testis with pigmented peritoneum from a Japanese quail embryo, numerous melanocytes penetrate in its interstitial tissue. If, instead of a testis, an ovary is transplanted under similar conditions, then the melanocytes may be found in the medulla or between the secondary sex cords at the rim of the ovary.

Origin of ovarian follicle cells in birds.

In the embryonic Japanese quail ovary, transplanted on chicken chorioallantoic membrane (CAM), follicle cells are derived from somatic cells of the ovarian surface epithelium. No evidence was found for a contribution of other cell groups of the quail ovary in the formation of follicle cells. This may be demonstrated on PAS stained sections, by following the transfer of carbon particles, initially applied on the surface epithelium.

Thermoregulatory ability and the thyroid gland: Their development in embryonic Japanese quail ( Coturnix c. jaaponica)

1. During development, fertile Japanese quail eggs show some increase in resistance to cooling. 2. During development, mean thyroid follicle cell height and total thyroidal iodine increase rapidly, until shortly before hatching. 1. One to 2 days before hatching, follicle cell height and thyroidal iodine content are abruptly reduced, but both return to former levels on the day of hatching.