• Title/Summary/Keyword: germ cells

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Germ Cell Degeneration during Mammalian Spermatogenesis (포유류의 정자형성과정 중 생식세포의 변화)

  • 김종민
    • Proceedings of the KSAR Conference
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    • 2001.10a
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    • pp.11-13
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    • 2001
  • 사람을 포함한 포유류의 정자형성과정은 시상하부에서 분비된 생식소자극호르몬 방출호르몬 (gonadotropin releasing hormone)의 영향 하에 뇌하수체에서 합성 분비되는 난포자극호르몬 (follicle stimulating hormone; FSH) 과 황체화호르몬 (luteinizing hormone; LH)에 의해서 조절된다. LH의 라이디히 세포 (Leydig cells) 자극으로 인한 testosterone 의 합성분비가 성체(adult)의 정자형성과정과 그 유지(maintenance)에 매우 결정적이다. 반면, FSH는 미성숙 개체의 정소에서 일어나는 예비적 정자형성과정에 있어 중요한 역할을 하며, 성체에서도 질적인 면에서의 정자형성과정에 관여하는 것으로 사려된다. 그러므로, 시상하부-뇌하수체-정소의 축(axis)을 이루는 어느 한 성분에서라도 이상이 생기면 정자의 형성과정은 치명적인 영향을 받을 수 있다. (중략)

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Factors Affecting the Productivity of Germ-line Chimeras from Jl Embryonic Stem Cells (Jl 배아주세포를 이용한 효율적인 생식선 이행 카이미라의 생산)

  • Kim, S.U.;Koo, B.S.;Jeong, S.;Lee, T.H.;Yu, S.L.;Nam, Y.I.;Kim, J.L.;Hyun, B.H.;Shin, H.S.;Lee, K.K.;Sang, B.C.;Yu, D.Y.
    • Korean Journal of Animal Reproduction
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    • v.25 no.1
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    • pp.71-77
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    • 2001
  • This experiment was designed to improve the production efficiency of germ-line chimeric mice from phospholipase C (PLC)-$\beta$3 or peroxiredoxin (Prx) E -targeted ($\Delta$) ES cells by the investigating the manipulation conditions and characteristics of Jl ES cells. Four targeting clones were isolated to investigate the karyotypical and morphological stability prior to injection. All clones ($\Delta$PLC$\beta$-3 C3, $\Delta$Prx II C3, C10 and I5) showed more than 80% euploidism, however, most of $\Delta$PLC$\beta$-3 C3 clones were extensively differentiated compared to the other clones. Nine of 13 $\Delta$Prx II chimeras appeared to have at least 80% chimerism, whereas $\Delta$PLC$\beta$-3 C3 chimeras had 20% chimerism at most. Therefore, the morphological stability of ES cells under stable euploidism might mainly affect the production rate of high-coat chimeric mice. To increase the collection rate of injectable blastocysts (IBs), 5 to 10 week -aged C57BL/6J female mice were sacrificed at 3.5 days post-coitum. Ten week-aged mice were the most optimal IB donors by showing the highest collection rate (2.94/mouse) of injectable blastocysts without increase of non-injectable embryos (0.29/mouse). Foster mothers might be another factor because ICR x C57BL/6J F1 foster mother showed more increased productivity in litter size (2.8 vs. 5.6) and chimera (0 vs. 35.3%) than those of ICR foster mothers. In conclusion, the efficient production of germ-line chimeras mainly depends on the maintenance of ES cell morphology during targeting procedure, and the establishment of manipulation conditions might be a key point to maximize it.

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Germ Cell Differentiations During Spermatogenensis and Taxonomic Values of Mature Sperm Morphology of Pinctada martensii (Bivalvia, Pteriomorphia, Pteriidae)

  • Kim, Jin-Hee;Kim, Sung-Han;Lee, Ki-Young
    • The Korean Journal of Malacology
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    • v.27 no.3
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    • pp.273-282
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    • 2011
  • The ultrastructural characteristics of germ cells during spermatogenesis and mature sperm morphology in male Pinctada martensii were investigated by transmission electron microscope observation. The morphologies of the sperm nucleus and the acrosome of this species are the oval shape and cone shape, respectively. Spermatozoa are approximately $47-50{\mu}m$ in length including a sperm nucleus (about $1.24{\mu}m$ in length), an acrosome (about $0.60{\mu}m$ in length), and tail flagellum (about $45-47{\mu}m$). The axoneme of the sperm tail shows a 9+2 structure. In P. martensii in Pteriidae, a special substructure showing a thick and wide triangular shape which is composed of electron-dense opaque material (occupied about 50% of all, the upper part of the acrosomal vesicle), appeared in the upper region (part) of the acrosomal vesicle, while the lower region (part) of the acrosomal vesicle is composed of electron-lucent material. Thus, this special structure, which exist in the upper part of the acrosomal vesicle in P. martensii, is somewhat different from those of other subacrosomal vesicle in other families in subacrosomal vesicles. Therefore, we assume that the existence of a special substructure showing a thick and wide triangular shape in the acrosomal vesicle of the spermatozoon can be used as a key characteristic for identification of P. martensii or other species in Pteriidae in subclass Pteriomorphia. The number of mitochondria in the midpiece of the sperm of this species are five (exceptionally sometimes four), as one of common characteristics appear the same number of mitochondria in the same families of superfamilyies. This species in Pteriidae does not contain the axial rod and satellite fibres which appear in the species in Ostreidae in subclass Pteriomorphia. These characteristics can be used for the taxonomic analysis of the family or superfamily levels as a systematic key or tools.

Differentiation of Human ES Cells to Endodermal Lineage Cells

  • Sung, Ji-Hye;Lim, Chun-Kyu;Cho, Jae-Won;Park, Hye-Won;Koong, Mi-Kyoung;Yoon, Hyun-Soo;Jun, Jin-Hyun
    • Proceedings of the Korean Society of Developmental Biology Conference
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    • 2003.10a
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    • pp.60-60
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    • 2003
  • Embryonic stem (ES) cells have property of self-renewal and can differentiate into the cells of all three primary germ layers. Recently, many growth factors, alteration of culture condition and gene modifications have been used to differentiate mouse and human ES cells into specific cell types. This study was performed to evaluate the differentiation protocol for human ES cells to the endodermal lineage cells. Human ES cells (Miz-hESl ) were cultured on STO feeder layer mitotically inactivated with mitemycin C, and embryoid bodies (EBs) were formed by suspension culture. Differentiation protocol of EBs consisted of three steps: stage I, culture of EBs for 6 days with ITSFn medium; stage II, culture of stage I cells for 8 days with N2 medium ; stage III, culture of stage II cells for 22 days with N2 medium. mRNA levels of the endodermal lineage differentiation genes were analyzed by semi- quantitative RT-PCR. The Oct-4 expression, a marker of the pluripotent state, was detected in undifferentiated human ES cells but progressively decreased after EBs formation. Differentiating human ES cells expressed marker genes of endodermal differentiation and pancreatic islet cells. GATA4, a-fetoprotein, Glut-2, and Ngn3 were expressed in all stages. However, albumin and insulin were expressed in only stage III cells. The human ES cells can be differentiated into endodermal lineage cells by multiple step culture system using various supplements. We are developing the more effective protocols for guided differentiation of human ES cells.

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Regional Difference in Distribution of Glycoconjugates in Mouse Epididymis (생쥐 부정소 부위별 당쇄 분포의 차이)

  • 계명찬
    • Development and Reproduction
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    • v.5 no.2
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    • pp.167-173
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    • 2001
  • To characterize the difference in glycoconjugates of mouse epididymis, lectin labeling of the tissue section was conducted using Ulex europaeus agglutinin I(UEA I), succinylated wheat germ agglutinin(sWGA), and Griffonia simplicifolia lectin-I(GSL-I). UEA I which binds to outer $\alpha$-L-fucose residue that is a terminal sugar of the side chain branched from oligosaccharide chain gave the labeling in the proximal caput epithelia exclusively. Lumen was commonly labeled in all of the organ. It suggested that the glycoconjugates bearing outer $\alpha$ -L-fucose residue were largely expressed in the initial segments ot epididymis and subjected to secretion. GSL-I which binds to terminal $\alpha$ -D-galactosyl residue of glycoconjugates gave the labeling in the cytoplasm of clear cells and basal cells, and cilia in corpus and cauda regions but not in the caput region. There was no vast difference in labeling pattern by sWGA which binds to N-acetyl-glucosamine residue among the epididymal regions. Clear cells in corpus and cauda epithelia showed more intense labeling by sWGA compared to principal cells, suggesting the functional specialization of this type of cells. The labeling intensities of luminal content by UEA I and sWGA decreased in cauda region compared to corpus region suggesting the presence of enzymatic activities responsible for processing the $\alpha$-L-fucose and N-acetyl-glucosamine residues from secreted glycoconjugates. In summary, the difference in glycoconjugates bearing the $\alpha$-L-fucose, $\alpha$-D-galactose, and N-acetyl-glucosamine residues according to the type of epithelial cells and epididymal segments suggests functional specialization and different roles of each segment in the processing of sperm surface antigens during the epididymal transit.

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