• Journal of Microbiology and Biotechnology
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• 제16권9호
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• pp.1347-1354
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• 2006

The aims of this study were to establish a simple and effective method for isolating male germline stem cells (GSCs), and to test the possibility of using these cells as a new approach for male infertility treatment. Testes obtained from neonatal and adult mice were manually decapsulated. GSCs were collected from seminiferous tubules by a two-step enzyme digestion method and plated on gelatin-coated dishes. Over 5-7 days of culture, GSCs obtained from neonates and adults gave rise to large multicellular colonies that were subsequently grown for 10 passages. During in vitro proliferation, oct-4 and two immunological markers (Integrin ${\beta}1,\;{\alpha}6$) for GSCs were highly expressed in the cell colonies. During another culture period of 6 weeks to differentiate to later stage germ cells, the expression of oct-4 mRNA decreased in GSCs and Sertoli cells encapsulated with calcium alginate, but the expression of c-kit and testis-specific histone protein 2B(TH2B) mRNA as well as the localization of c-kit protein was increased. Expression of transition protein (TP-l) and localization of peanut agglutinin were not seen until 3 weeks after culturing, and appeared by 6 weeks of culture. The putative spermatids derived from GSCs supported embryonic development up to the blastocyst stage with normal chromosomal ploidy after chemical activation. Thus, GSCs isolated from neonatal and adult mouse testes were able to be maintained and proliferated in our simple culture conditions. These GSCs have the potential to differentiate into haploid germ cells during another long-term culture.

• Applied Microscopy
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• 제16권2호
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• pp.75-91
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• 1986

Differentiation of the rat testis was studied by light and electron microscope from the fetal stage up to the newborn or adult stage. The purpose of the present study is to investigate the ultrastructural changes of seminiferous tubules and interstitial tissue during the developmental process. The results were as follows: the seminiferous tubule diameter began to increase from birth and was fully developed at 30 to 40 days of age through intratubular cell proliferations. Basement membrane and myoid cells lining the seminiferous tubules were differentiated at 17 days gestation. At the fetal stage, seminiferous tubules were primarily composed of Sertoli cells and the differentiation of Sertoli and germ cells progressed from the newborn stage. Spermatids and immature spermatozoa are appeared at 40 days of age, so from this time, spermatogenesis occurred actively until the adult stage. Sertoli cells aided germ cell differentiation and phagocytosed the parts of the spermatid cytoplasm. Leydig ce]] development follows a biphasic pattern: a fetal phase and then an adult phase from 20 days of age. In conclusion, the rat testis is already developed to some extent by the fetal stage and is functional after 50 days of age. Therefore, these findings indicate that differentiation of Sertoli and Leydig cells precedes the onset of spermatogenesis.

• Applied Microscopy
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• 제33권3호
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• pp.243-250
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• 2003

넙치의 웅성생식세포의 발달과 정자 구조를 광학현미경과 투과전자현미경을 이용하여 관찰하였다. 곡정세관의 각 소낭내의 생식상피에서는 분열 증식중인 정원세포군이 염기성 염료에 미약하게 반응하기 시작한다. 정소조직의 계속적인 발달로 각 소낭내에는 분열증식중인 정모세포군을 관찰할 수 있다. 이후 소엽내강에는 상당수의 초기 정세포를 관찰할 수 있으며, 더욱 더 발달된 변태된 정자를 볼 수 있다. 투과전자현미경에 의한 관찰에서 간기의 정원세포는 세포질이 미약한 반면, 커다란 핵과 뚜렷한 인을 가진다. 제1정모세포의 핵내에서는 연접사 복합체 (synaptonemal complex)가 뚜렷하고 세포질내에서는 세포소기관이 증가한다. 제2정모세포의 핵질은 응축되어 높은 전자밀도를 나타낸다. 정세포는 세포질과 핵질이 응축되면서 타원형의 형태를 취하고, 미토콘드리아는 핵의 후방으로 위치한다. 변태를 마친 정자는 두부와 미부로 구성되며 무첨체형이다. 두부 후방에서는 cytoplasmic collar는 6개의 미토콘드리아를 가진다. 미부에서는 axonemal lateral fin을 관찰할 수 있다. 미부 편모 축사의 횡단면은 "9+2"의 미세소관 구조를 나타낸다.

• Asian-Australasian Journal of Animal Sciences
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• 제13권7호
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• pp.894-896
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• 2000

In vitro fertilization can be used for salvaging superior buffalo germplasm which otherwise goes waste after the slaughter of animals. This technology has also increased our basic understanding of growth of germ cells and embryos. The requirement of growing embryos is peculiar and stage specific. In the present study the cleavage and development of buffalo embryos were studied with homologous (buffalo) and heterologous (goat) oviductal cell co-culture systems. The cleavage rate improved significantly (p<0.01) in both homologous and heterologous co-culture as compared to control (55.3, 46.8 and 11.4%). The morula formation using homologous and heterologous oviductal cells also increased significantly as compared to control group (43.6, 21.9 & 1.9%). There was no blastula formation in control group, but addition of oviductal cells either from homologous or heterologous species significantly increased the blastula formation (9.5, 12.5%). The cleavage rate and embryo development was slightly better (non significant) in homologous as compared to heterologous oviductal cell culture. It was concluded that the use of oviductal cell co-culture (homologous and heterologous species) have significantly improved cleavage and development of buffalo embryos in vitro.

• 치과방사선
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• 제11권1호
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• pp.33-40
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• 1981

The author studied on the effects of x-irradiation to the development of digital malformation in gestation rats. The time-matings occured between 6 p.m. and 8 a.m. and females with copulation. plugs at 8 a.m. were isolated and properly marked for evidence of copulation. The lower abdomen of mothers were exposed to x-irradiation on the 11½th day of gestation, the critical period developing digital malformation, respectively 100, 150, 200, 250, 300 and 350 rads. At 18½th day of post-conception total 50 pregnant females were dissected and the incidence of digital malformations were obtained. Rat embryos on the 12, 13, 14, 15, 16th day of gestation irradiated by 250 rads were examined for morphogenesis of digital malformation. Digital radiating lines were examined in water and histologically by H-E stain. Supra vital stain samples by Nile-blue sulfate in 37℃ normal saline were prepared for the observation of cell necrosis regions and morphogenesis of digits. The results obtained were as follows; 1. By x-irradiation on 11th day of gestation, digital malformations of Ectrodactylia, Syndactylia Polydactylia and Hematodactylia were developed. Ectrodactylia showed the effective relationship to the amount of irradiation, however Syndactylia ans Polydactylia did not. 2. By x-irradiation, cell necrosis of digital germ was appeared markedly, but in 48 hours after irradiation was depressed to the periphery of digital germ and in 72hours after irradiation was disappeared. Digital radiating line showed marked stage of malformation in 48hours after irradiation and continued to show the same amount of physiological cell necrosis as the compared control group in 72hours. after irradiaion. But in the Syndactylia, physiological cell necrosis was not able to be recognized. 3. Ectrodactylia induced by x-irradiation was considered as the direct resoult of cell necrosis of digital origin, however, Polydactylia and Syndactylia were considered as the resoult of some effect in repair process of x-irradiation damages.

• 한국가금학회:학술대회논문집
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• 한국가금학회 2005년도 제22차 정기총회 및 학술발표회
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• pp.66-67
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• 2005

배자 생식세포 발달에 관련된 메카니즘을 밝혀내기 위해서, 닭 배자 생식기에서 추출한 원시 생식세포의 단백질체 지도를 만들었다. 총 500 배자를 6일간 배양하여 배자 생식기를 획득했고, 7-10일 배양 후, 배양된 원시생식세포는 2차원 젤 전기 영동법에 의해 분할되어 졌다. 유의적 발현 수준을 나타낸 많은 단백질 스팟 들은 MALDI-TOP 와 LC-MS/MS에 의해 확인되었으며, 89개의 단백질 스팟 중에 50개의 mass spectra 들이 데이터베이스에서 조류 단백질과 일치함을 확인하였다. 본 실험에서 행한 단백질체 지도는 형질전환 연구와 생식세포 생물학 분야에 중요한 참고 문헌으로 가치를 가질수 있을 것이다.

• Journal of Plant Biotechnology
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• 제1권1호
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• pp.56-60
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• 1999

Sexual reproduction is an essential process in the propagation of flowering plants. Recent advances in plant cell biology and biotechnology have brought new and powerful methodologies to investigate and manipulate the reproductive processes of angiosperms including agronomically important crop plants. Successful cryopreservation of maize, rye and triticale pollen and young embryos of microspore-and zygote-origine contributes to long term preservation of important plant germ-lines in gene banks. Discovering morphogenetic characteristics of the different developmental pathways taking place in wheat and maize androgenesis in vitro helps to influence the procedure to produce genetically and phenotipically stable homozygous doubled haploid plants for breeding purposes. Detailed ultrastructural and cell-biological studies on the developmental sequences of male and female gametophyte development in wheat, experimental protocols developed to isolate and micromanipulate egg cell protoplasts, make it possible to use plant gametes and the sexual route itself to produce genetically improved organisms. Plant gametes can become useful tools for crop improvement in the near future. Recent achievements by our laboratory in this field are reviewed in the present paper

• Safety and Health at Work
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• 제11권2호
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• pp.152-158
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• 2020

Background: The Globally Harmonized System of Classification and Labeling of Chemicals (GHS) was developed to enhance chemical classification and hazard communication systems worldwide. However, some of the elements such as building blocks and data sources have the potential to cause "disharmony" to the GHS, particularly in its classification results. It is known that some countries have developed their own lists of classified chemicals in accordance with the GHS to "standardize" the classification results within their respective countries. However, the lists of classified chemicals may not be consistent among these countries. Method: In this study, the lists of classified chemicals developed by the European Union, Japan, Malaysia, and New Zealand were selected for comparison of classification results for carcinogenicity, germ cell mutagenicity, and reproductive toxicity. Results: The findings show that only 54%, 66%, and 37% of the classification results for each Carcinogen, Mutagen and Reproductive toxicants hazard classes, respectively are the same among the selected countries. This indicates a "moderate" level of consistency among the classified chemicals lists. Conclusion: By using classification results for the carcinogenicity, germ cell mutagenicity, and reproductive toxicity hazard classes, this study demonstrates the "disharmony" in the classification results among the selected countries. We believe that the findings of this study deserve the attention of the relevant international bodies.

• Applied Microscopy
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• 제29권3호
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• pp.353-362
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• 1999

플라스틱 제품의 가소제로 널리 사용되며, 내분비 교란물질로도 알려져 있는 di-(2-ethylhexyl) phthalate (DEHP)를 사춘기 이전 흰쥐에 1주일 동안 구강 투여 (1g/kg, 3g/kg, 5g/kg)한 후 분화중인 정소의 미세구조에 미치는 영향을 조사하였다. DEHP 처리군에서는 대조군에 비하여 세정관 직경이 매우 작았으며, Leydig 세포, Sertoli 세포 및 분화중인 생식세포들의 증식이 억제되었다. 실험군에서 세정관 사이에 존재하여 테스토스테론을 분비하는 Leydig세포는 이질염색질이 증가하고, 세포질내에서 활면소포체의 발달이 미흡하였으며, 리소솜과 지방적이 증가하는 특징을 보였다. 세정관 내에서 Sertoli 세포는 세포질의 크기가 감소하고, 핵막이 불규칙해지거나, 염색질이 응축되어 있는 모습이 나타나며, 세포질내에서 리소솜과 액포들이 증가하였다. 실험군 흰쥐 정소내에서 분화중인 생식세포들의 핵은 이질염색질이 증가하거나, 응축되어 있고, 인의 분리현상이 관찰되기도 하며, 심한 경우 핵내에 공포가 형성되어 있거나, 괴사과정에 있는 생식세포들도 관찰되었다. 이와 같은 정소 미세 구조의 변화는 DEHP 투여량의 농도에 의존성을 보이며, 이 화합물은 Leydig 세포의 테스토스테론 합성 기능을 방해하고, 이어서 Sertoli 세포의 구조와 기능이 손상되어 정자형성과정 중인 생식세포들의 증식과 분화가 억제되는 것으로 사료된다.

• Clinical and Experimental Reproductive Medicine
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• 제39권1호
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• pp.1-9
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• 2012

The safety of human exposure to an ever-increasing number and diversity of electromagnetic field (EMF) sources both at work and at home has become a public health issue. To date, many in vivo and in vitro studies have revealed that EMF exposure can alter cellular homeostasis, endocrine function, reproductive function, and fetal development in animal systems. Reproductive parameters reported to be altered by EMF exposure include male germ cell death, the estrous cycle, reproductive endocrine hormones, reproductive organ weights, sperm motility, early embryonic development, and pregnancy success. At the cellular level, an increase in free radicals and $[Ca^{2+}]i$ may mediate the effect of EMFs and lead to cell growth inhibition, protein misfolding, and DNA breaks. The effect of EMF exposure on reproductive function differs according to frequency and wave, strength (energy), and duration of exposure. In the present review, the effects of EMFs on reproductive function are summarized according to the types of EMF, wave type, strength, and duration of exposure at cellular and organism levels.