Haploid germ cells

The ovaries perform two major functions (i) the storage, maturation, and expulsion of healthy haploid germ cells (i.e., oocytes) for fertilization, and (ii) the synthesis and secretion of hormones to prepare the reproductive tissues for the establishment and maintenance of pregnancy, to properly regulate gonadotropin secretion from the hypothalamic-pituitary axis, to induce appropriate sexual behaviors, and to provide lactation. The two primary functional units in the ovaries are the maturing follicles and the corpora lutea. 

Meiosis involves one cycle of chromosome replication followed by two cycles of cell division to produce haploid germ cells from a diploid premeiotic cell (see Figure 21-34). 

Meiosis The process by which haploid germ cells are produced from diploid cells. 

Tanaka H, Iguchi N, Egydio de Carvalho C, Tadokoro Y, Yomogida K, Nishimune Y (2003) Novel actin-like proteins T-ACTIN 1 and T-ACTIN 2 are differentially expressed in the cytoplasm and nucleus of mouse haploid germ cells. Biol Reprod 69 475 82... 

Stem cells, haploid germ cells, somatic cells, transformed cells. The ancient unicellular life forms survived under the most adverse conditions in a chemically hostile, overheated (boiling water pouring lava volcanic fumes), chemically imbalanced as to excessive acidity or alkalinity, and heavily radioactive environment. The y-rays-irradiated but radiation-resistant Deinococcus radiodurans (Figure 4) suffers genomic damage it is its chaperone proteins in its proteome that perform the rescue of the genome (Mediterranean Instimte for Life Sciences, Split, Croatia). 

Comment. One could speculate that the unicellular and the early multicellular life forms existed in a highly stressed life style, and replicated rapidly without rest, or senescence. In contrast, in the mature multicellular hosts, the overwhelming number of the somatic cell populations encode just one particular task, divide seldom if ever, and keep the rest of their genomes silenced (under the control of silenced promoters). Stem cells are in the minority, divide asymmetrically, but seldom, otherwise they rest Haploid germ cells exert little activity until after become zygotes (the united sperm and the ovum). Thereafter, they dictate the ontogenesis of the individual. How their intron counts reflect to their life style ... 

H. platycena, 2901 Halymeniaceae, 2891 Halymenia floresii, 28, 2891, 2904 Haploid germ cells, 2421 Haplophyllum, 719 Haraldiophyllum spp., 29 Harmala alkaloids, 554, 564, 568 Harmaline, 1352 Harman, 1170, 1352 Harmane, 1170... 

Delmas y van der Hoom F, Mellstrom B, Jegou B, Sassone-Corsi P. Induction of CREM activator proteins in spermatids down-stream targets and implications for haploid germ cell differentiation. Mol Endocrinol 1993 7 1502-1514. 

Tosaka M, Okajima F, Hashiba Y, Saito N, Nagano T, Watanabe T, Kimura T, Sasaki T (2000) Identification and characterization of testis specific ornithine decarboxylase antizyme (OAZ-t) gene expression in haploid germ cells and polyamine-induced frameshifting. Genes Cells 5 265-276... 

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