• Applied Microscopy
• /
• v.29 no.4
• /
• pp.459-470
• /
• 1999

To investigate the changes during the differentiation of the cerebral neurons of the embryogenic day (ED) 9 and 10, investigated the ultrastructural changes in the cerebral neurons by Electromicroscope, also cerebral protein, the activity of dehydronases (LDH, MDH and SDH) and changes of adenosine triphosphate concentration were analyzed, the result obtained are as follows. In the ultrastructural changes in the cerebral neurons, chromatin in 9 day-old chick embryos are comparatively distributed to even in neucleoplasm and could investigate very prominently that nuclear membrane is double-layer. Esperially, Rough endoplasmic reticulum (RER) and Golgi complex are developed well, also polysome is investigated and synaptic vesicles were scattered. In 10 day-old chick embryos, chromatin evenly spread and nuclear membrane could be differentiated prominently. Rough endoplasmic reticulum (RER) contain cytoplasm, mitochondria and Golgi complex are comparatively developed well. In 9 day-old cultural group of chick embryo cerebrum were separated 37 polypeptide bands and In 10 day-old cultural group of chick embryo cerebrum were separated 38 poly -peptide bands. The more culture time increase, the more the activity of dehydronases (LDH, MDH and SDH) increase. LDH activity was 11.07 (9th day) and 12.12 (10th day), MDH activity was 11.89 (9th day) and 13.44 (10th day) and SDH activity was 8.45 (9th day) and 10.52 (10th day) respectively. The ATP concentration degreesed 10 day-old cultural group than 9 day-old cultural group.

• The Korean Journal of Zoology
• /
• v.31 no.3
• /
• pp.191-206
• /
• 1988

Chick embryos which have received a single injection of the organophosphate compound,malathion (0.1 mg, 0.5 mg, 1.0 mg or 2.0 mg in 0.05 ml of corn oil) via the yolk sac at certain times (2 daya, 4 days or 6 days after incubation) have been investigated. After 9 days of incubation, chick embryos were harvested to investigate the effects of malathion on the development of cerebrum morphologically and biochemically. The effects of simultaneous injection of malathion and nicotinamide were also compared. On ultrastructural examination, neurons in cerebral cortex showed to be inhibited in their differentiation by malathion; nuclear irregularity, swelling of endoplasmic reticulum, and cytoplasmic vacuoles were observed. On cytochemical study of acetylcholinesterase(AChE) by electron microscope, the positive reaction products of this enryme were localized at the membrane of nucleus and endoplasmic reticulum of neurons. Inhibition of AChE activty was severe in groups treated with relatively low doses, which was consistent with the results of spectrophotometric analysis. The activity of lactate dehydrogenase(LDH) of cerebrum in groups treated with malathion was higher than that of the control group. The nicotinamide adenine dinucleotide(NAD) content of chick embruo treated with malathioti decreased significantly, and nicotinamide coinjection raised the NAD level as compared with the control group, thus preventing malathion-induced momhological alteration. In conclusion, it is suggested that malathion changes the ultrastructure of differentiating neurons and alters some enzyme activities in chick embryo cerebrum, and the severity of which is consistently dose-or age-dependent.

• Applied Microscopy
• /
• v.20 no.2
• /
• pp.71-80
• /
• 1990

It was investigated the morphological changes of differentiating epidermal cells in chick embryos. Ectodermal cells at 3 days after incubation were cuboidal, their nuclei were large, and rough endoplasmic reticulum and mitochondria were distributed in the cytoplasm. At 5 days after incubation, there were periderm and one basal layer in epidermis. The cells of basal layer were columnar, their nuclei were round, and rough endoplasmic reticulum and free ribosomes were developed. Also, peridermal cells were flat, chromatins were partially condensed and glycogen particles were abundant. No periderm showed and cells of basal layer formed intermediate layer at 9 days after incubation. Basal cells of intermediate layer were cuboidal, neighboring cells were anchored by desmosomes and tonofibrils and free ribosomes were evenly scattered. At 15 days after incubation, stratum corneum and stratum germinativum were distinguished. In cells of stratum germinativum, tonofibrils, free ribosomes and desmosomes were well developed. And then, the shedding of stratum corneum were showed at 17 days after incubation and stratum corneum were well developed after hatching.

• Korean Journal of Poultry Science
• /
• v.23 no.2
• /
• pp.61-69
• /
• 1996

Primordial germ cells (PGCs) were manipulated as part of the system to produce transgenic chickens. PGCs were isolated from the germinal crescent of developmental stage 6 to 8 donor emhryos of the Korean Native Ogol Chickens (KNOC). These PGCs were transfected with plasmid DNA containing the lac Z gene by liposome mediated transfection methods. The lac Z gene was transfected and expressed in the PGCs. These transfected PGCs were injected into the germinal crescent of White Leghorn embryos (stage 6 to 8). The injected transfected PGCs migrated via the circulatory system into the future gonad and expression observed in the gonads of 3 day old chick. Of the 47 embryos and 3 day old chickens, one positive PGCs gonad from sacrificed young chickens was detected by appearance of blue cells. Plasmid DNA with the foreign gene was incorporated into the population of germ cells in the gonad. These results demonstrate that PGCs can he transfected and then transferred for colonization into the gonad, and show the potential to ultimately manipulate the genetic material of the chicken gernline.

• Applied Microscopy
• /
• v.21 no.2
• /
• pp.1-13
• /
• 1991

In order to investigate the factors of the control mechanism of somitogenesis, early chick embryos (H-H stage $8{\sim}13$) were treated with heat shock, ${\alpha}$-amanitin and cycloheximide and morphological changes of somite were examined by light microscopy, transmission and scanning electron microscopy. In normal chick embryo, somites were formed from the somitomere which preexisted in segmental plate. Somites were wrapped with extracellular collagen fibrils and connected with neural tube, notochord and ectoderm. And then, somites were differentiated to sclerotome, dermatome and myotome by the interaction of nervous tissue. Abnormal somites were observed after formation of six or seven so mites in heat shock treated group. Amounts of collagen fibrils were obviously decreased in this group. In cycloheximide treated group, most so mites were smaller and neural tube formation was incomplete. Chromatins were condenced and formed several heterochromatins in the nucleus of somite cells. Lipid like cytoplasmic dense mass and lipid droplets were also observed. Segmentation of somites seemed to be normal progress in ${\alpha}$-amanitin treated group. Center of somite, however, hollowed in longitudinal sectioned samples. These results suggested that so mites were already existed in the segmental plate as the form of somitomere. Segmented somites were contacted with neural tube or notochord and the somites were tightly connected with each other by the extracellular collagen fibrils which were secreted from neuroepithelium and somite cells. Somites are thought to differentiate into sclerotome, dermatome and myotome by these interactions.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.11
• /
• pp.1562-1568
• /
• 2016

Monochromatic green light-emitting diodes (LED) light stimuli influences the posthatch growth performance of chicks. This study was undertaken with the following objectives: i) to examine whether the green LED light stimuli induces an overheating effect by determining weight loss rate of fertile eggs during incubation period; ii) to look for the development of eyes and other primary organs at different ages of embryos and newly hatched chicks. Arbor Acres fertile broiler eggs (n = 480) were randomly assigned to 3 incubation groups and exposed to continuous white light, green light, or a dark environment (control) from the first day to 19 d of incubation. The light sourced from LED lamps with the intensity of 30 lx at eggshell level. The results showed that either green or white light stimuli during incubation did not significantly affect the weight loss rate of fertile eggs, hatching time, hatchability, chick embryo, or body weight (BW), the weight percentage of heart, liver, and eyes, as well as obvious systematic abnormalities in eye weight, side-to-side, back-to-front, or corneal diameter from 15 d of embryogenesis to 6 d of posthatch (p>0.05). Compared with the dark condition, green light stimuli during incubation tended to increase feed intake (p = 0.080), improved the BW gain of chicks during 0 to 6 day posthatch (p<0.05), and increased the percentage of pectoral muscle to the BW on 3- and 6-day-old chicks. In addition, embryos or chicks in green light had lower weight percentage of yolk retention on 19 d of embryogenesis and 1 d of posthatch in comparison to those in dark or white group (p<0.05). These results suggest that providing 30 lx green LED light stimuli during incubation has no detrimental effect on the development of eyes, heart and liver of embryos and hatchlings, but does have potential benefits in terms of enhancement of the chick growth during the early posthatch stages. In addition, the fertile broiler eggs stimulated with 30 lx green LED light during incubation does not cause an overheating effect.

• The Korean Journal of Zoology
• /
• v.32 no.1
• /
• pp.55-73
• /
• 1989

The effect of tryptophan or serotonin on the early stage of chick brain development has been morphologically investigated using an electron microscope. The electron micrographs of neural plate cells of 1-day chick embryo treated with tryptophan or serotonin showed irregularity, evagination and disruption of nuclear membrane and nuclear chromatin condenstation, nucleolar margination and segregation. Hypertrophy of stalks, vesicles and vaculoes were seen and dilated and disrupted rough endoplasmic reticulum and underdeveloped neurotubules were also observed. In mesenchyme cells of tryptophan or serotonin administered 18 hr embryo, irregular nuclear membrane, swollen mitochondria, dilated rough endoplasmic reticulum and very large yolk granules were observed. Furthermore, DNA, RNA and protein contents of the embryos treated with typtophan or serotonin were considerably lower than those of control group. The amount of tubulin of the experimental groups was also greatly lower than that of control, suggesting that the impairment of microtubule formation occurred. Tryptophan or serotonin administration might depress the biosynthesis, of nucleic acid and protein including some enzymes tested. It seems that the serotonin formed from exogeneous tryptophan might inhibit the degradation of yolk granule by feedback regulation mechanism so as to impair microtububle and microvilli formation followed by a malformation of chick embryos.

• Animal cells and systems
• /
• v.5 no.3
• /
• pp.205-209
• /
• 2001

Mesenchymal cells from the leg buds of stage 24-chick embryos differentiated into chondrocytes when plated at high density. Treatment of high density micromass culture of chick mesenchymal cells with cytochalasin D(CD, 2 $\mu$M for 24 h) resulted in inhibition of chondrogenesis. CD treatment was found to affect the expression of the contractile protein $\alpha$-smooth muscle actin ($\alpha$-SM actin). In control cultures, $\alpha$-SM actin uniformly expressed from culture day 2, but the CD-treated cells induced expression of $\alpha$-SM actin from the first day of culture followed by a continuous increase. Expression of pan-cadherin (P-cadherin) decreased as chondrogenesis proceeded in the control culture, whereas the CD-treated cells showed sustained expression. These results propose a close connection of chondrogenic differentiation with expression of $\alpha$-SM actin and P-cadherin.

• Applied Microscopy
• /
• v.23 no.2
• /
• pp.78-83
• /
• 1993

To investigate the effect of mercuric chloride on the pectoral muscel cells during chick embryogensis, chicken embryos were treated with mercuric chloride. Monoclonal antibodies against myosin were prepared for the localization of differentiation of thick filaments detected by the use of protein A-gold complex as a cytochemical marker. The effect of mercuric chloride was appeared not only to be ascribed with the reduced formation of myofibrilogenesis but also associated with induced change of morphology by the inhibition of protein synthesis.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 1999.11a
• /
• pp.11-33
• /
• 1999

This study was conducted to determine the embryonic stages for the isolation of the highest number of PGCs and to improve PGCs enrichment method. The primordial germ cells(PGCs) from different sources of chick embryos were isolated. The embryonic stage having the highest number of PGCs from each sources was selected ; 1-day-old embryos for germinal crescent (stage 6-8), 2.5-day-old embryos for blood (stage 17-18) and 5.5-day-old embryos for gonad (stage 27-28). The number of PGCs from one embryonic germinal crescent, blood and gonad was about 87$\pm$1.8, 103$\pm$4.0, and 932$\pm$10.9, respectively. The viability of PGCs after Ficoll from each sources was similar, showing approximately 70%. the PGCs enrichment method was improved using Ficoll density gradient centrifugation. After this step the purity of PGCs from germinal crescent, blood, and gonad was 45$\pm$9.10%, 85$\pm$1.18%, and 86$\pm$0.19%, respectively. Also, PGCs were picked up by mouth pipette to improve the purity. This improved method for the separation of PGCs from different sources will serve as a useful too to preserve the foundation stocks of poultry and to produce germline chimeras.