نتایج جستجو برای: germ cell
تعداد نتایج: 1696571 فیلتر نتایج به سال:
In some species such as flies, worms, frogs and fish, the key to forming and maintaining early germ cell populations is the assembly of germ plasm, microscopically distinct egg cytoplasm that is rich in RNAs, RNA-binding proteins and ribosomes. Cells which inherit germ plasm are destined for the germ cell lineage. In contrast, in mammals, germ cells are formed and maintained later in developmen...
Segregation of the germ line from the soma is an essential event for transmission of genetic information across generations in all sexually reproducing animals. Although some well-studied systems such as Drosophila and Xenopus usematernally inherited germ determinants to specify germ cells, most animals, including mice, appear to utilize zygotic inductive cell signals to specify germ cells duri...
In Drosophila melanogaster, primordial germ cells are specified at the posterior pole of the very early embryo. This process is regulated by the posterior localized germ plasm that contains a large number of RNAs of maternal origin. Transcription in the primordial germ cells is actively down-regulated until germ cell fate is established. Bulk expression of the zygotic genes commences concomitan...
Primordial germ cell development uses programmed cell death to remove abnormal, misplaced or excess cells. Precise control of this process is essential to maintain the continuity and integrity of the germline, and to prevent germ cells from colonizing locations other than the gonads. Through careful analyses of primordial germ cell distribution in developing Drosophila melanogaster embryos, we ...
BACKGROUND Phthalate exposure induces germ cell effects in the fetal rat testis. Although experimental models have shown that the human fetal testis is insensitive to the steroidogenic effects of phthalates, the effects on germ cells have been less explored. OBJECTIVES We sought to identify the effects of phthalate exposure on human fetal germ cells in a dynamic model and to establish whether...
In this study we show that mouse primordial germ cells and fetal germ cells at certain stages of differentiation express E-cadherin and alpha and beta catenins. Moreover, we demonstrate that the formation of germ cell aggregates that rapidly occurs when monodispersed germ cell populations are released from embryonic gonads in culture is E-cadherin mediated, developmentally regulated, and depend...
Defining normal and malignant germ cell development is crucial for understanding the biology and behavior of germ cell tumors. Germ cell tumors show significant similarities with immature germ cells. Furthermore, treatment sensitivity of germ cell tumors reflects the intrinsic characteristics of the cell of origin, and their derivatives. The aim of this thesis was to identify factors involved i...
Background: Germ cell aplasia (G.C.A) is one of the most important testicular causes of infertility and azospermia.In this condition the seminiferous tubules are only lined by a single layer of sertoli cell. In some cases, there is focal area with spermatogenic activity. Methods: We studied infertile men with G.C.A referred to Jahade Daneshgahi of Iran during 1381-82, retrospectively. All ...
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