The vascular system of the chick embryo. XVII. The development of branching of the coronary arteries in the chick embryos with experimentally induced left-half heart hypoplasy.
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Animals↗
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Results for “Chick Embryo”
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Using the amniotic cavity of the developing chick embryo for the in vivo culture of early-stage mammalian embryos.
The fertile chicken egg may provide an effective, inexpensive method for promoting the development of early-stage embryos from other species. Presently, the loss of viability associated with the in vitro culture of mammalian embryos is hindering the use of in vitro fertilization with farm animals. Consequently, alternative in vitro laboratory methods are needed for the culture of mammalian embryos. A new method has been developed that involves the culture of mammalian embryos in the amniotic cavity of a developing chick embryo. Chick embryos were placed into shell-less incubation (37 C) at the 72-h developmental stage. After 24 h of shell-less incubation, agarose-embedded mammalian embryos were injected into the amniotic cavity of the chick embryo. The mammalian embryos were first placed into a drop of liquid agarose. One to four embryos were then aspirated into a beveled injection pipette and cooled, allowing the agarose to harden. Following penetration of the amnion with the beveled pipette, the agarose cylinder containing the embryos was expelled into the amniotic cavity. The shell-less culture system was then returned to incubation at 37 C for an additional 72 to 96 h. Following incubation, the amniotic cavity containing both chick and mammalian embryos was isolated and the agarose-embedded mammalian embryos were harvested. Significantly more embryos developed in the chick embryo amnion than in the control medium alone. Results obtained using this method on laboratory animals (mice) and on domestic mammals (goats and cattle) indicate that the chick-embryo amnion can support the development of early-stage, mammalian embryos to the blastocyst stage of development.(ABSTRACT TRUNCATED AT 250 WORDS)
Amnion↗
[Outgrowth of neurite from hamster and chick embryo retinal explants on the retinal basement membrane of different developmental stages of chick embryos].
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Animals↗
Effect of variations in temperature of injected saline on early development of chick embryo.
Development of chick embryo is sensitive to the incubation temperature and increase or decrease in incubation temperature produces defect in development but the effect of drug solution injected at variable temperatures on developing chick embryo has not been established so far. Fresh embryonated eggs were incubated and saline was administered at various temperatures after 17 hr of incubation. Embryos were harvested to see the effect of temperature variations of injected saline on neural tube formation. Normal neural tube development was seen only at 37 degrees C, hot or cold saline produced maldevelopment of neural tube. Thus it is concluded that any solution or drug which needs to be injected should ideally be used at 37 degrees C, as temperature lower or higher than that may vitiate the results.
Animals↗
Expression of FGFR1, FGFR2 and FGFR3 during early neural development in the chick embryo.
Studies involving chick embryos have implicated FGFs in neural induction and patterning as well as in other developmental events. Detailed analyses of FGF receptor expression at early stages of neural development have not been reported for the chick embryo and are incomplete for other vertebrate classes. Here we show the expression patterns of three FGF receptors, (FGFR1, FGFR2 and FGFR3) in embryonic stages between gastrulation and limb bud formation, focussing particularly on neural tissues. Between neural induction and neurulation, all three receptors are expressed in the neural plate albeit with distinct and overlapping distributions. During early neuromere formation FGFR1 transcripts are present throughout the neural tube, while transcripts for FGFR2 and FGFR3 become restricted to regions of the diencephalon and spinal cord. A little later, FGFR2 and FGFR3 are additionally expressed in the anterior midbrain and within the hindbrain. During later neuromere development, FGFR1 transcripts become localised to the telencephalon, anterior dorsal diencephalon and throughout the midbrain and hindbrain, whereas FGFR2 mRNA is restricted to dorsal telencephalon, dorsoanterior midbrain and hindbrain. FGFR3 is also expressed in anterior midbrain and hindbrain during this developmental period, and is additionally expressed in the posterior telencephalon, in the pretectum, and at the zona limitans intrathalamica. The observed expression patterns of all three receptors within the hindbrain, including rhombomere boundaries, are complex and dynamic. Expression patterns within the somites, eye, head mesenchyme, branchial arches, limb buds, nephric kidney and pharynx are also described.
Animals↗
[Hypothalamo-hypophyseal relationships in the chick embryo].
When a chick embryo, deprived of its hypothalamo-pituitary complex by partial decapitation, is bearing a grafted hypophysis, this gland is unable to induce a normal development of the thyroid. The volume of this gland is reduced and, consequently, the fixation of iodine is decreased from the age of 16 days. Some authors think that there are no hypothalamo-pituitary correlations in the chick embryo. On the contrary, these observations lead to admit their appearance towards the end of the incubation.
Animals↗
Correlation between induction of xenobiotic metabolism and DNA damage from chemical carcinogens in the chick embryo in vivo.
Chick embryo liver and lung have high levels of basal mixed-function oxidase (MFO) enzyme activities during embryonic development. These activities are differentially inducible by 3,4,3',4'-tetrachlorobiphenyl (TCB) and phenobarbital (PB) in liver but are not inducible in lung. Nucleated chick embryo erythrocytes have no detectable basal or inducible MFO activities. Following induction by TCB or PB, embryos were exposed to the direct-acting carcinogen methyl methane-sulfonate (MMS) or the indirect-acting carcinogens aflatoxin B1 (AFB1) or 7,12-dimethylbenz[a]anthracene (DMBA). DNA damage was measured in liver, lung and blood by the DNA alkaline elution technique. Maximum DNA damage by MMS in liver, lung and blood and by AFB1 and DMBA in liver and lung occurred approximately 3 h after exposure. DNA damage was rapidly repaired in liver and lung, but was not repaired in blood. AFB1 and DMBA caused no detectable DNA damage in blood, even following PB or TCB induction. MMS-induced DNA damage was unaffected by induction in all groups with the exception that PB decreased DNA damage in liver at the low dose of MMS. AFB1- and DMBA-induced DNA damage was increased in liver and decreased in lung following induction by PB and TCB in 14-day embryos. In contrast, AFB1-induced DNA damage was increased by PB and decreased by TCB in 7-day embryonic liver. These results suggest that MFO induction can increase or decrease DNA damage in vivo, but that the direction and magnitude of change in DNA damage can vary depending on the inducer, carcinogen, tissue and the developmental age being investigated.
9,10-Dimethyl-1,2-benzanthracene↗
Ca2(+)-mobilizing receptors of gastrulating chick embryo.
1. Gastrulating chick embryo cells (stages 3-5 by HH) possess Ca2(+)-mobilizing receptors for ACh and ATP; insulin and noradrenaline have a weaker effect on [Ca2+]i mobilization. 2. The ED50 value for ACh is 4 (+/- 0.5) X 10(-6) M and for ATP 20 (+/- 5) X 10(-6) M. 3. Addition of ACh and ATP to dissociated chick embryo cells causes rapid accumulation of IP3. 4. The stimulatory effects of ACh and ATP on [Ca2+]i mobilization and IP3 rapid formation are both additive.
Acetylcholine↗
Embryotoxicity and teratogenicity of formocresol on developing chick embryos.
White Leghorn chick embryos were used to investigate the embryotoxicity and teratogenicity of 25 and 50% Buckley's formocresol. Embryos were injected at 48 h and sacrificed on the ninth day of incubation. The percentage of mortality of sham and vehicle controls was 4.8 and 17.7%, respectively, whereas eggs injected with 25 and 50% formocresol displayed a 40 and 100% mortality rate. Gross morphological abnormalities, weights, and crown-rump lengths were determined, demonstrating that Buckley's formocresol is embryotoxic and teratogenic in chick embryos. Gross morphological changes were noted to include cranial hematomas, facial abnormalities, eye and beak deformities as well as alterations in feather germ appearance. Histological changes included alterations in the organization of the eyes, and formation of the beak, palate, vasculature, musculature, cartilage, and bone. Moreover, experimental embryos displayed a retardation of development in that they lagged behind their controls by approximately 24 to 36 h.
Abnormalities, Drug-Induced↗
Maturation of the hypothalamo-adenohypophyseal-gonadal (HAG) axes in the chick embryo.
In the chick embryo the components of the hypothalamo-adenohypophyseal-gonadal (HAG) axes initially function independently. On day 13 of development in the male embryo, luteinizing hormone (LH) from the adenohypophysis initiates regulation of testosterone (T) synthesis and secretion by the testes, and as a consequence plasma T levels reach a maximum value on day 13.5. The establishment of this feed-forward phase of the pituitary-testicular axis involves an increase in the numerical density (NV) of testicular LH receptor-positive interstitial cells (IC) as a result of elevated plasma LH levels ("up regulation"). The elevated plasma T levels on day 13.5 cause plasma LH concentrations to decrease immediately after day 13.5, initiating the feedback phase of the endocrine axis. The NV of testicular LH receptor-positive IC also decreases at the same time, continuing to decline for the remainder of the embryonic period as LH receptor complexes are internalized and plasma T levels decrease. The decrease in the NV of testicular LH receptor-positive IC and the internalization of the LH receptor complexes reflect a "desensitization" of the IC, in which there is a decrease in the ability of LH to stimulate T synthesis and secretion by the IC ("down regulation"). In the male chick embryo the hypothalamus begins to regulate the adenohypophyseal-testicular unit during the last third of embryonic development. There appears to be a series of similar, albeit not as well verified, events that occur in the female embryo with respect to the development of the adenohypophyseal-ovarian axis.
Animals↗
Alcohols induce interferon in primary chick embryo cells.
Primary chick embryo cells (CEC), cultured in vitro, produce interferon (IFN) following alcohol treatment. Brief exposure of cells to methanol, ethanol, 2-propanol, or butanol resulted in the production of an acid-labile IFN which could be detected in the supernatant medium as early as 60 min after removal of the drug. Following "priming" of the cells by homologous IFN, these four alcohols induced even greater yields of IFN: up to 4,000 units per 10(7) cells of an acid-stable IFN were detected. In contrast, priming of CEC with IFN had no effect on the yield of IFN induced by a standard viral inducer, avian reovirus. Maximal IFN production by ethanol in IFN-primed cells depended on both the priming dose of IFN and length of contact with the cells, as well as the in vitro age of the cell cultures. Complete neutralization by polyclonal anti-chick IFN serum, of both the acid-labile and acid-stable preparations induced by ethanol treatment confirmed that both were chicken IFNs. This report describes the general characteristics of IFN induction in primary chick embryo cells by alcohols, with particular emphasis on ethanol, chemically the simplest IFN inducer reported to date.
Alcohols↗
Actin microheterogeneity in chick embryo fibroblasts.
Secondary chick embryo fibroblasts contain three distinct actin species--alpha, beta, and lambda, in the approximate ratio of 1:6:3--with the same molecular weights but different isoelectric points. The most acidic of these components, alpha, comigrates on isoelectric focusing gels with the major actin of cardiac and skeletal muscle, while lambda, the most basic of the actins, comigrates with smooth muscle actin. The three components have overlapping methionine-containing tryptic peptides. All three actins are found to be present in actomyosin and cytoskeleton preparations from chick embryo fibroblasts. Identification of alpha-actin as the major actin from sarcomere-containing cells is confirmed by comparing embryonic chicken pre- and post-fusion myoblast cultures. Following myoblast fusion, the relative amount of alpha-actin increases until it changes from a minor actin component to the predominant actin species in the culture.
Actins↗
Effects produced by the administration of high doses of 1,25-dihydroxycholecalciferol to the chick embryo.
White Leghorn chick embryos were injected on the 15th day of incubation with 70 to 300 pmoles 1,25-(OH)2D3. All doses produced hypercalcemia; with the highest dose, the concentration of calcium in serum started to rise 4 h after the injection, reached a peak 20 h after, and was still high 48 h after. Twenty hours after the injection of the same dose, the concentration of inorganic phosphorus in the serum was significantly lower than in the corresponding controls. The tibias from 17-day-old chick embryos injected with 300 pmoles on day 15 were shorter, lighter, and had a lower ash content than those from controls. Histological signs of resorption appeared to be reduced with respect to controls, but no precise quantitation was conducted. The fact that hypercalcemia was not accompanied by hyperphosphatemia may suggest that the vitamin stimulates resorption of calcium from the shell, which is mainly formed by calcium carbonate rather than from the bone from which calcium and phosphate are usually resorbed together.
Animals↗
The extracellular matrix of normal chick embryo fibroblasts: its effect on transformed chick fibroblasts and its proteolytic degradation by the transformants.
Extracellular matrix (ECM), prepared from chick embryo fibroblasts, contains fibronectin as the major structural protein along with collagen and other polypeptides as less abundant protein components. When Rous sarcoma virus-transformed chick embryo fibroblasts are cultured on the ECM in the presence of the tumor promoter tetradecanoyl phorbol acetate, the transformed cells lose their characteristic rounded morphology and align on and within the ECM fibrillar network. This restrictive aspect of ECM is only temporary, however, and with time (24-72 h) the transformed cells progressively degrade the ECM fibers and resume their rounded appearance. The matrix degradation can be monitored by employing biosynthetically radiolabeled ECM. The addition of purified chicken plasminogen to the Rous sarcoma virus-transformed chick embryo fibroblast cultures enhances the rate and extent of ECM degradation, due to the elevated levels in the transformed cultures of plasminogen activator. Plasminogen-dependent and -independent degradation of ECM has been characterized with regard to sensitivity to various natural and synthetic protease inhibitors and to the requirement of cell/ECM contact. Plasminogen-dependent degradation of ECM occurs rapidly when ECM and cells are in contact or separated, whereas plasminogen-independent degradation is greatly reduced when ECM and cells are separated, which suggests that cell surface-associated proteolytic enzymes are involved. A possible role in ECM degradation has been indicated for cysteine proteases, metallo enzymes, and plasminogen activator, the latter as both a zymogen activator and a direct catalytic mediator.
Animals↗
Cellular morphology and extracellular space at rhombomere boundaries in the chick embryo hindbrain.
The chick embryo hindbrain is a segmented region of the CNS characterised by repeated blocks of neuroepithelial cells, known as rhombomeres. Individual rhombomeres are polyclonal compartments, defined both by cell lineage restriction and by the restricted expression of development control genes, that later acquire specific patterns of neuronal differentiation and axon outgrowth. The interfaces between adjacent rhombomeres are defined by boundaries across which cells do not move; the boundaries contain specialised cells and are preferentially colonised at early stages of development by extending axons. In this study, routine electron microscopy and high-pressure cryopreservation, a technique that avoids artifacts of chemical fixation, have been used to examine the morphology of rhombomere boundaries through a staged series of chick embryos. We find that the boundary regions contain enlarged extracellular spaces and that these form conduits for axons subsequently extending in the circumferential plane of the hindbrain. Labeling the ventricular surface of the neuroepithelium with DiI crystals in aqueous suspension revealed the morphology of individual cells in the intact neural tube, and demonstrated unusual fan-shaped arrays of cells at the boundaries. These findings contribute further to the evidence that cells at rhombomere boundaries differ from those in rhombomere centres, and leads to hypotheses about both the mechanism of development of the boundaries, and the role they may play in hindbrain patterning.
Animals↗
Quantitation of delta-crystallin messenger RNA during lens induction in chick embryos.
Embryonic chick cells of the presumptive lens ectoderm are induced to differentiate into a lens by the optic vesicle, an outgrowth from the developing brain. This lens induction involves formation of the lens placode by cell elongation between about 44 and 50 hr of development, followed by invagination of the placode between about 50 and 55 hr of development. The amount of delta-crystallin messenger RNA (mRNA) in heads of embryos between 48 and 72 hr of development was determined by molecular hybridization with [3H]DNA complementary to purified delta-crystallin mRNA. An average of approximately 0.5 pg of delta-crystallin mRNA was found per embryonic head at 48 hr of development. This leads to approximately 265 molecules of delta-crystallin mRNA per lens cell, if one assumes that the mRNA is confined to the lens rudiment, as is indicated by immunofluorescence studies of delta-crystallin performed by other investigators. Pulse-labeling experiments with [35S]methionine indicated that the delta-crystallin mRNA is being translated already at this time. delta-Crystallin mRNA accumulated at an average rate of 1 molecule per cell per minute between 48 and 72 hr of development. Thus, by extrapolation, the initiation of delta-crystallin mRNA accumulation coincides with the initiation of lens placode formation at approximately 43-44 hr of development, which is some 8-9 hr after the initiation of lens induction by the optic vesicle. These data suggest that delta-crystallin synthesis is regulated by the accumulation of delta-crystallin mRNA during lens induction in chick embryos.
Age Factors↗
The mechanism of regulation of the growth of organs in embryogenesis. II. The action of splenic tissue transplants from chick embryos, enlarged under the influence of adult spleen on growth of the organs of normal chick embryos.
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Animals↗
Lung development in the chick embryo. II. Choline and ethanolamine kinase activity in the developing lungs of normal and hypophysectomized chick embryos.
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Age Factors↗