• Asian-Australasian Journal of Animal Sciences
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• v.12 no.8
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• pp.1188-1191
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• 1999

Primordial germ cells (PGCs) of White Leghorn chicken embryos as a donor were transferred to Rhode Island Red chicken embryos as a recipient. At 48-50 h (stage 13-15) of incubation of fertilized eggs, donor PGCs, which were taken out from blood vessels of donor embryos, were injected into blood vessels of recipient embryos. Sex of the treated embryos was determined after the transfer of PGCs using remaining blood samples. In the present experiments, survival rate of the treated embryos was 33.3% for homo-sexual and 35.4% for hetero-sexual transfers of PGCs, respectively, when determined at 17 days of incubation. In this study, most of the treated embryos could not survive more than 18 days of incubation, though the reason for that was not clarified in the present work. The gonalds removed from embryos that died after 18 days of incubation and the organs from newly hatched chicks were examined for morphological and histological features. The gonads removed from the embryos with homo-sexual transfer of PGCs showed normal development in appearance. On the contrary, some (35.3%) of the embryos with hetero-sexual transfer of PGCs possessed abnormal gonads similar to ovotestis by histological observation. In cases where the gonads developed to be normal organs (64.7%) the sex of embryos was the same as recipient ones. The present results suggest that hetero-sexual transfer of the PGCs may bring about the possibility of development of the embryos bearing sexually different gametes, spermatogonia or oogonia.

• Fisheries and Aquatic Sciences
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• v.8 no.1
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• pp.27-33
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• 2005

This is a subsequent study to our previous finding that Pacific oysters, Crassostrea gigas, gained a so-called upper plateau concentration, around 30,000 ng/g dry weight digestive gland for benzo(a)pyrene, showed reproductive behavior but produced their ensuing reproductive outputs damaged. A serial dilution of sediment elutriates from Jinhae Bay, Korea, where pollution was progressive, were exposed to gametes of the Pacific oyster for 0, 5, 10, 20, 30, and 60 min to detail the pollutant effects on very young specimens. There was an apparent critical dilution over which adverse effects are evident. This was $10\%$ of the present sediment elutriate, corresponding to 0.3 ng/g on the basis of total polycyclic aromatic hydrocarbons (PAHs) for the oyster. Within the dilution the embryonic development was not influenced by the duration of exposure to its gamete stage. At higher dilutions over the critical dilution, occurrence of abnormality increased dependent on the pollutant dilution and the duration of exposure. Similar trends were also found in larval mortality. However, overall, the chemical toxicity was more significant to morphogenesis than to survival, suggesting a potential recruitment of the pollutants-induced abnormal larvae in the wild population to threaten the population integrity.

• The Korean Journal of Malacology
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• v.19 no.1
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• pp.33-40
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• 2003

To obtain the basic information on culture conditions for the larvae of Saxidomus purpuratus, experiments were conducted on the population from southern coast for (1) the success in fertilization and development from artificial fertilization among different months of a year, (2) the viability of sperms after exposure to seawater, (3) and the effects of temperature, salinity, and food organism on the survival and growth of larvae. Gametes obtained from dissection showed high rate of fertilization at all months. But the rate of development was higher only May-July. Developmental success seemed to be related with the quality of eggs at the time of fertilization. Developmental times for 2-cell, 4-cell, 8-cell, blastula, trochophore larva, and veliger larva at 20$^{\circ}C$ were 1.5, 2, 4, 18, 24, and 32 hr, respectively. Sperms could survive for more than 8 hr, however, actively swimming sperms could be found within 1 hr after exposure to seawater. It is recommended that sperms should be used for fertilization as soon as possible when they are exposed to seawater. At temperature of 35$^{\circ}C$, all the larvae died during 48 hr. Larval survival decreased when salinity was either lower than 20 psu or higher than 40 psu, and was 0% when salinity was 10 psu. Optimal range of temperature and salinity for rearing larvae of S. purpuratus were 20-25$^{\circ}C$ and 20-40 psu, respectively. Larvae grew from 111.5 to 235.3 ${\mu}$m during 21 days. Larvae fed mixed diets grew faster than unialgal diets. The fastest growth was observed when larvae were fed on the mixture of Isochrysis galbana and Nannochloris oculata.

• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.355-359
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• 2015

The cause of infertility is either fertilization failure or early embryonic death. The aetiology may involve a combination of many factors, e.g. genetic factors, abnormalities in the gametes nutritional disorders, inadequate luteal function, and delayed ovulation. This study was conducted to investigate the effect of microorganisms collected from uterus of Hanwoo cattle on early embryonic development. Microorganisms isolated from the uterus of Hanwoo cattle included Bacillus cereus (Bc), Bacillus thuringiensis (Bt), Staphylococcus warneri (Sw) and Enterococcus faecalis (Ef). When cultured with Bc, Bt, Sw, and Ef, oocytes were not developed into a blastocyst in vitro. The proportion of blastocyst was dramatically increased after reducing the number of microorganisms ($10^4CFU/ml$). Interestingly, the proportion of blastocyst was decreased by adding the Sw and Ef. These results indicate that among intrauterine microorganisms, Sw and Ef strains negatively affect theearly embryonic development, thereby aggravate the rates of implantation and pregnancy. These findings will provide useful information for association studies in other pig populations.

• ALGAE
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• v.23 no.2
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• pp.119-133
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• 2008

We cultured a tubular marine green alga, originally identified as Capsosiphon groenlandicus (J. Agardh) K.L. Vinogradova, from Amaknak Island, Alaska. The alga had an alternation of heteromorphic generations in which tubular monoecious fronds produced quadriflagellate zoospores and/or biflagellate isogametes. The gametes fused to produce cysts or Codiolum-like zygotes with long, tortuous stalks. Cysts and codiola produced 8-16 aplanospores, which germinated in situ to yield upright fronds. Fronds arising from both aplanospores and zoospores displayed a distinctive development in which non-septate colorless rhizoids from the base of the initially uniseriate, Ulothrix-like filament were transformed into septate uniseriate Ulothrix-like photosynthetic filaments. These transformed filaments then developed new basal non-septate rhizoids. This pattern of rhizoids becoming filaments, which then produced new rhizoids, was repeated to yield a tuft of up to 50 fronds. Periclinal and longitudinal divisions occurred in each filament, starting basally, until the mature tubular thallus was achieved. Pyrenoid ultrastructure revealed several short inward extensions of chloroplast lamellae, each of which was surrounded by pyrenoglobuli. Analysis of ribosomal SSU and ITS sequences placed this alga in the family Ulotrichaceae, order Ulotrichales, together with but as a distinct species from North Atlantic Capsosiphon groenlandicus. Analysis of a partial ITS sequence from authentic Capsosiphon fulvescens, the current name of the type of the genus Capsosiphon, indicated that neither our material nor C. groenlandicus belongs in that genus, and we propose a new genus, Pseudothrix, to accommodate both species. We propose P. borealis for the North Pacific entity formerly called C. groenlandicus and make the new combination P. groenlandica for the Atlantic species.

• Development and Reproduction
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• v.7 no.2
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• pp.81-88
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• 2003

Initiation and activation of sperm motility are prerequisite processes for the contact and fusion of male and female gametes at fertilization. The phenomena are under the regulation of CAMP and $Ca^{2+}$ in vertebrates and invertebrates. Mammalian sperm requires $Ca^{2+}$and cyclic AMP for the activation of sperm motility. Cell signaling for the initiation and activation of sperm motility has been well studied in the ascidians, Ciona intestinalis and C. savignyi and salmonid fishes. In Ciona, whose cell signaling for activation of sperm motility has been established, the sperm-activating and -attracting factor released from unfertilized egg requires extracellular $Ca^{2+}$ for activating sperm motility and eliciting chemotactic behavior of the activated sperm toward the egg. On the other hand, the cyclic AMP-dependent phosphorylation of protein is essential for the initiation of sperm motility in salmonid fishes. A decrease in the environmental Ti concentration surrounding the spawned sperm causes a li efflux and $Ca^{2+}$ influx through the specific $K^{+}$ channel and dihydropyridine-sensitive L-/T- type $Ca^{2+}$ channel, respectively, thereby leading to the membrane hyperpolarization and $Ca^{2+}$ influx. The membrane hyperpolarization synthesizes cyclic AMP, which triggers the luther Process of cell signaling, i.e., cyclic AMP-dependent protein phosphorylation, to initiate sperm motility in salmond fishes.almond fishes.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.1026-1034
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• 2000

As described here, most recently developed methods for improving reproduction performance of domesticated animals such as cattle, swine and chicken have been considered to be also usable for restoring some sorts of endangered and/or extinct wild animals in the very near future. Especially, the techniques for in vitro storage of gametes obtained from dead animals shortly after the death, probably 24 h following the sacrifice are also available for obtaining some of experimental specimens. In case of the endangered animals, nobody will be allowed to use any tissues from the living animals, therefore, e.g., the use of skin tissues from these bodies is another possibility of restoring the living animals. Regarding the use of skin tissues, the most highly usable tools must be the cloning techniques for reviving rare cells from the living body. Most possible techniques for cloning cells is nuclear transfer from rare species to highly relative species, and this is the case of germ cells, e.g., primordial germ cells (PGCs) of avian species. One of the possibilities is the nuclear transfer of Crested Ibis (Nipponia nippon) to the PGCs of chicken, resulting in the PGCs with transferred nucleus from the ibis. In mammalian species, the same procedure as in the case of birds would be successful, e.g., the removed nucleus from Giant Pandas will be transferred to the cell, such as somatic cells or germ cells from black bears or lesser pandas, leading to the production of transnucleared cells in the body of female black bears. These two cases are most promising techniques for reviving endangered animals in the world, particularly in Asian countries, mainly in China. As a conclusion, possible production of cloned animals carrying transnucleared cells from endangered animals, such as Giant Pandas and Crested Ibis, may be reproduced gradually in the near future. Scientists are, therefore, required to convert the paradigm from domestic animals to wild animals, including endangered and/or extinct animals on the earth.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 1998.07a
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• pp.12-18
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• 1998

Tremendous progress has been made over the past quarter-century studying the genetics of gametogenesis and the resulting gametes and embryos. Studies merging molecular techniques and conventional cytogenetics are now beginning to bridge the gap between what we have learned about the meiotic process in males and females and what we know of the mitotic chromosomes of zygotes. Numerical abnormalities in sperm, oocytes and embryo can now diagnosed by fluorescence in situ hybridization (FISH). "At risk" couples can, therefore, have only unaffected embryos replaced in the sterus and avoid the possibility of terminating a pregnancy that might only be diagnosed as affected later gestation. Single-cell genetic analysis has also provided powerful tools for studying genetic defects arising during early human development. Recent studies of sperms, oocytes and cleavage-stage human embryos have revealed an unexpectedly high incidence. These genetic abnormalities are likely to contribute to early pregnancy loss and have important implications for improving pregnancy rates in infertile couples by assisted reproduction. The widespread use of preimplantation genetic diagnosis (PGD) awaits further documentatio of safety and accuracy. Other issues also must be addressed. First, the ethical issues regarding germ cell and embryo screening must be addressed including what diseases are serious enough to warrant the procedure. Another concern is the use of this technology for non-genetic disorders such as gender selection. Finally, the experimental nature of these procedure must continually be discussed with patients, and long-term follow-up studies must be undertaken. Development of more accurate and less expensive assays coupled with improved assisted reproductive technology success rates may make PGD a more widely use clinical tool. The future awaits these development.velopment.

• Korean Journal of Animal Reproduction
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• v.18 no.4
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• pp.285-297
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• 1995

The mammalian oviduct is a place where ontogeny of an animal begins. Nowadays, however, it is possilbe to manipulate a part of physiological events occurring in the oviduct so that fertilization of gametes and early embryonic development of zygotes could proceed outside oviductal environment. Rabbit zygotes readily develop to blastocysts in a conventional culture condition. Most of the mouse fertilized eggs do so when cultured under a specific environment, e.g., in a medium containing ethylenediamine tetraacetic acid. Similarly, a significant number of zygotes from rat, sheep, pig or cattle can develop to blastocysts if they are cultured in the presence of particular component which appear to be somewhat species-specific. Instead of changing the components of medium, somatic cells including oviductal epithelial cells, have widely been used to improve mammalian embryonic development in vitro. Many investigators have reported that mammalian zygotes, whether fertilized in vivo or in vitro, could develop to blastocysts when they were cultured on a monolayer of various kinds of somatic cells or even in a somatic cell-conditioned medium. While little is known about the nature of embryotrophic factor(s) produced in vitro by somatic cells, the existence fo oviduct-specific protein(s) has consistently been demonstrated in many laboratories. Some of these proteins are reported to be associated with oviductal eggs. However, the physiological role of these proteins has still to be determined. Recently we observed that the perivitelline space of mouse oocytes was fluorescently stained with various fluorochrome-protein conjugates following ovulation into the oviducts or upon their expossure to oviductal extracts. Furthermore, it was also found that cattle or pig oviductal fluid gave similar results when examined using mouse ghost ZP. These observations lead to suggest that mammalian oviduct induces changes of biochemical properties of oocytes. Further studies are needed to clarify the nature of oviductal factor(s) and the physiological meaning of the reaction.

• Development and Reproduction
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• v.19 no.4
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• pp.209-215
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• 2015

Red spotted grouper, Epinephelus akaara is a popular aquaculture species in many Asian countries. This species is a protogynous hermaphrodite that first differentiates into female and changes to male later. Due to this reproductive characteristic, stable supply of male and female gametes is a key to the success of seed production in this species. Thus, understanding early gonadal differentiation is required to develop effective sex control techniques. Red spotted grouper were reared in indoor tanks and sampled every 5 days from 40 days post-hatch (DPH) to 130 DPH. Changes of gonadal tissues were examined and analyzed by means of histology. A pair of gonadal primordium has already existed underneath the kidney in the posterior part of the body cavity at 38 DPH when this study began. Gonadal primordia of 38, 40 DPH consisted of germ cells surrounded by a few somatic cells. The blood vessel was observed in the gonadal primordium at 45 DPH. The number of somatic cells and size of gonadal primordium increased age-dependently up to 60 DPH. Formation of ovarian cavity was obvious by two protuberant aggregations of somatic cells at 65 DPH. Completed ovarian cavity and oogonia were first observed in the gonad of one fish sample at 105 DPH. Based on these histological observations, it can be suggested that induction of primary male differentiation could be more successfully applied at around 60 DPH in this species.