• International Journal of Industrial Entomology and Biomaterials
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• v.18 no.2
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• pp.77-82
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• 2009

The egg shell of the tropical tasar silkworm, Antheraea mylitta is formed from the substances secreted by the follicular epithelium during the late vitellogenic stage. TEM study reveals the inner travecular and outer lamellar layer of chorion. The travecular layer is composed of the innermost wax layer, inner and outer chorionic layer. The inner and outer chorionic layers are connected to each other by vertical pillers forming of cavities. The lamellar layer is perforated by the aeropyles. SEM study reveals the differentiation of an anterior surface of the egg shell into four zones-micropylar, edge, aeropyles crown and disc zone. In the mycosis infected eggs the aeropyles and egg-shell surface are fully packed with the hyphae of the fungus, Aspergillus sydowi blocking of plastron respiration and causing the death of developing embryo so that mycosis infected eggs become sterile.

• Korean Journal of Veterinary Research
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• v.13 no.2
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• pp.111-118
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• 1973

The placentation in the golden hamster (Mesocricetus auratus) and the morphological changes occuring in its placenta from implantation to parturition have been observed by light microscope. The results obtained were summarized as follows. 1. The development of the placenta in the fertilized ovum implanted on the day 5 of gestation was described with increasing gestational age. 2. On the day 8 of gestation, the chorioallantoic placenta was formed by fusion of the allantois to the chorion of ectoplacental cone. 3. On the day 13 of gestation, Reichert's membrane with the parietal yolk sac disappeared in a circumscribed area antimesometrially.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.4
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• pp.194-197
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• 2015

The amniotic membrane is the innermost layer of fetal membrane and is attached to the chorion in the placenta. This membrane has been used for nearly a century in varied fields such as ophthalmology, reconstructive surgery, and burn treatment. In this case report, we used a human amniotic membrane to repair an iatrogenic oroantral communication that occurred during the extraction of the patient's right upper second molar. A splint was given after the perforation was covered with human amniotic membrane and healing was clinically evaluated at various intervals. The outcome of the study revealed that the human amniotic membrane was an efficient graft material for repairing the defect caused by an iatrogenic oroantral communication following tooth extraction.

• Korean Journal of Veterinary Research
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• v.23 no.1
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• pp.1-8
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• 1983

The purpose of the present study is to determine variations in synthesis of DNA in the nuclei of various elements of the golden hamster (Mesocricetus auratus) placenta with increasing gestational age from the eighth day post coitus to parturition. The method employed for such determination was autoradiography following injection of pregnant animals with tritiated thymidine. From the results reported, the following points are concluded. The mitotic activities of the endodermal cells of the visceral yolk sac and of the parietal yolk sac, the trophoblastic cells of the labyrinth and the trophospongium and the giant cells were decreased with increasing gestational age, The placentation was nearly completed by day 13 of pregnancy and the increase in size of labyrinth was by appositional growth from the trophospongial cells. It was considered that the inner trophoblastic cells in the vicinity of the fetal blood vessels were originated from the pure chorion. The interrelation among the various cells and the polyploidal giant cells in the placenta were discussed.

• The Korean Journal of Malacology
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• v.20 no.1
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• pp.55-63
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• 2004

Gonadosomatic index, condition index and reproductive cycle with the gonadal development of the female Octopus ocellatus were investigated by histological observations and morphometric data, from January to December, 2000. And changes in biochemical components of the ovary and the trunk tissues including the digestive organ associated with gonadal development were studied by biochemical analysis from January to October, 2001. The specimens were collected at the coastal waters of Buan, Jeollabuk-do, Korea, from January 2000 to October 2001. O. ocellatus is a dioecious organism. The gonad of O. ocellatus locates medially in posterior region of the body. Morphology of the ovary shows round and oval in shape, the average diameter and external colour of ripe ovary was 32 mm and semitransparent light brown in colour. As the ovary was getting mature, transparent elongated eggs covered with chorion were present in the ovarian cavity. Monthly changes in the gonadosomatic index (GSI) showed a similar pattern with those of the condition index. The GSI and condition index began to increase in March and reached the maximum in April. And then, their values decreased from May and reached the minimum in September. Reproductive cycle of O. ocellatus can be categorized into five successive stages: early developing stage (September to December), late developing stage (November to March), ripe stage (March to May), partially spawned stage (April to June), and degenerative/resting stage (June to October). Follicle cells attached to an oocyte were involved in vitellogenesis in the cytoplasm of the vitellogeneic oocyte and formation of chorion (secondary egg membrane) of the ovarian eggs. Spawning occurred between April and June. The spawning period was once a year and the peak took place between May and June. This species belongs to semelparity. According to changes in biochemical contents of the ovary and the digestive organ, monthly variations of moisture, total protein, total lipid and glycogen contents (%) in the ovary showed a negative correlationship with those of the trunk tissues including the digestive organ. Accordingly, it is assumed that the ovary only may be received nutrient supply (total lipid content) for gonadal development from the trunk tissues including the digestive organ (r = -0.55, p < 0.05).

• Applied Microscopy
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• v.15 no.1
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• pp.86-100
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• 1985

A observation of the ovarian development and oogenesis of Pieris rapae Linne has been carried out during metamorphosis using stereo-microscope, light microscope and electron microscope. The results obtained through this experiment are as follows: 1. The ovarian development and vitellogenesis begin at the 3-day old pupa and the 6-day old pupa respectively, and the adult ovary right after their emergence contains a few mature eggs. 2. The species described above are further observed at six different stages in oogenesis, and the results are summarized as follows. 1) Pieris rapae has polytrophic ovarioles. The cell organelles of the nurse cells are transfered to the oocyte through the ring canal at the early oogenesis. 2) At stage 2, the nuclear envelope of oocyte nucleus is less infolding than that of nurse cell nucleus. In the oocyte cytoplasm a large number of ribosomes are observed. 3) At stage 3 and 4, many micropinocytotic vesicles are observed in the oocyte cytoplasm. These vesicles are fused together to form large proteid yolks. 4) At stage 5, the vitelline membrane is laid down in the intercellular space between the follicle cells and oocyte. 5) At stage 6, the chorion is formed by the follicle cells. 6) A micropyle and a number of aeropyle are observed on the surface of a mature egg.

• Journal of Embryo Transfer
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• v.33 no.2
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• pp.69-73
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• 2018

This study was conducted to examine the influences of two human chorion gonadotrophins (hCGs) being injected into young or aged (45- to 65-week old) outbred (ICR) mice on developmental capacity of oocytes retrieved. In vitro-culture and parthenogenetic activation of oocytes retrieved were employed for the assessment. Superovulation was determined as being induced when more than 25 oocytes were retrieved. No aged mice were superovulated, while in contrast, 67-100% were superovulated in the 6- to 8-week-old (young) mice. In the aged, hCG injection yielded better retrieval (5 vs. 13 to 14.8 oocytes/mouse). Overall, no significant difference between two hCGs was detected but between the young and aged, significant differences in maturational arrest (0% vs. 39% MI arrest and 46% vs. 15% degeneration) and developmental capacity (24% vs. 46% 8-cell embryo development) were detected. In conclusion, hCG injection contributes to increasing oocyte retrieval from aged outbred mice, but the kinds of gonadotrophin influenced the efficiency of hyperstimulation induction in specific ages.

• Molecules and Cells
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• v.42 no.8
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• pp.589-596
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• 2019

${\beta}Pix$ is a guanine nucleotide exchange factor for the Rho family small GTPases, Rac1 and Cdc42. It is known to regulate focal adhesion dynamics and cell migration. However, the in vivo role of ${\beta}Pix$ is currently not well understood. Here, we report the production and characterization of ${\beta}Pix$-KO mice. Loss of ${\beta}Pix$ results in embryonic lethality accompanied by abnormal developmental features, such as incomplete neural tube closure, impaired axial rotation, and failure of allantois-chorion fusion. We also generated ${\beta}Pix$-KO mouse embryonic fibroblasts (MEFs) to examine ${\beta}Pix$ function in mouse fibroblasts. ${\beta}Pix$-KO MEFs exhibit decreased Rac1 activity, and defects in cell spreading and platelet-derived growth factor (PDGF)-induced ruffle formation and chemotaxis. The average size of focal adhesions is increased in ${\beta}Pix$-KO MEFs. Interestingly, ${\beta}Pix$-KO MEFs showed increased motility in random migration and rapid wound healing with elevated levels of MLC2 phosphorylation. Taken together, our data demonstrate that ${\beta}Pix$ plays essential roles in early embryonic development, cell spreading, and cell migration in fibroblasts.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2451-2456
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• 2003

In biological cell manipulation, manual thrust or penetration of an injection pipette into an egg is currently performed by a skilled operator, relying only on visual feedback information. Massive load of various micro injection of either genes, fluid or cells in the postgenomic era calls a more reliable and automatic micro injection system that can test hundreds of genes or cell types at a single experiment. We initiated to study cellular force sensing in zebrafish eggs as the first step for the development of a more controllable micro injection system by any inexperienced operator. Zebrafish eggs at different developmental stages were collected and an integrated biomanipulation system was employed to measure cellular force during penetrating the egg envelope, the chorion. First of all, the biomanipulation system integrated with cellular force sensing instrument is implemented to measure the penetration force of cell membranes and characterize mechanical properties of zebrafish embryo cells. Furthermore, implementation of cellular force sensing system and calibration are presented. Finally, the cellular force sensing of penetrating cell membranes at each developmental stages was experimentally performed. The results demonstrated that the biomanipulation system with force sensing capability can measure cellular force at real-time while the injection operation is undergoing. The magnitude of the measured force was in the range of several hundreds of uN. The precise real-time measurement should provide the first step forwards for the development of an automatic and reliable injection system of various materials into biological cells.

• Journal of Sericultural and Entomological Science
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• v.38 no.1
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• pp.48-52
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• 1996

Nosema bombycis was found on the both of surface and inside of silkworm eggs layed by infected female moth, maternal-mediated transmission of those pathogens via the surface or internal site of silkworm eggs were investigated. All of the meconia from infected female moths contained pathogenic spores, those concentration were 4.6(${\pm}$0.24)X106 /ml. The pathogens on the surface of nondiapause eggs were transmitted to the progeny larvae at the rate of 54.5%, however, lost their activity before hatching for the case of overwintered eggs or acid treatment(16% HCI at 46.2$^{\circ}C$ for 6 min). N. bombycis in the silkworm eggs localized at the serosa, yolk, embryo except chorion tissue in the silkworm eggs layed by infected female moths. Development of the pathognes in the eggs was synchronized with embryogenesis, which secured the safety of pathogens against environmental condition, resulting in the high transmissibility of 91.2${\pm}$1.80%.