• 제목/요약/키워드: Germ

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CR GEOMETRY/ANALYSIS AND DEFORMATION OF ISOLATED SINGULARITIES

  • Miyajima, Kimio
    • 대한수학회지
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    • 제37권2호
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    • pp.193-223
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    • 2000
  • In the late 1970's, M. Kuranishi proposed to control the moduli of the germ of a normal Stein space by deformations of the CR structure on the boundary. I this paper, we will see that it is naturally accomplished by considering stably embeddable deformations of CR structures.

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흰쥐 정소(精巢)의 분화(分化)에 관한 미세구조적(微細構造的) 연구(硏究) (Ultrastructural Study on the Differentiation of the Rat Testis)

  • 등영건;김완종;정인덕
    • 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.

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Unanticipated Gene Deletion in the Transgenic Chicken Employing Ovalbumin Promoter for Oviduct Specific Expression

  • Jang, Tae Young;Koo, Bon Chul;Kwon, Mo Sun;Roh, Ji Yeol;Kim, Teoan;Park, Young Sik
    • Reproductive and Developmental Biology
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    • 제37권3호
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    • pp.91-96
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    • 2013
  • Transgenic chickens have been spotlighted as an highly potent bioreactor for their fecundity, short generation time, and eggs associated with mass production of protein. In this study, we generated transgenic chickens exhibiting oviduct specific expression of human growth hormone fused to human transferrin for oral administration. Gene of the modified growth hormone located at downstream ovalbumin promoter (~3.6 kb) was introduced to stage X blastodermal cell employing retrovirus vector system. Several transgenic chickens were successfully generated. However, genomic analyses showed unexpected deletion within the transgene. The modification of the transgene seemed to occur during germ cell formation because the deletion was detected only from the sperm DNA of the G0 founder animal. There was no evidence of deletion in the somatic cell DNA samples of the same chicken. Consequently, same pattern of the deletion was confirmed in both somatic and germ cells of the G1 progeny.