. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure 1. (A) Whole mount of ovarian lobe viewed with transmitted light showing full-grown oocytes. The translucent region in the oocyte on the extreme left indicates the position of its germinal vesicle. (B) View of the same ovarian lobe using fluorescence to visualize the nuclei of somatic cells in the ovary. Each oocyte is surrounded by a number of follicle cells. Because of the thickness of this preparation, not all somatic cell nuclei are in focus. For this reason, many of them give a diffuse fluorescence image. Both ph
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure 1. (A) Whole mount of ovarian lobe viewed with transmitted light showing full-grown oocytes. The translucent region in the oocyte on the extreme left indicates the position of its germinal vesicle. (B) View of the same ovarian lobe using fluorescence to visualize the nuclei of somatic cells in the ovary. Each oocyte is surrounded by a number of follicle cells. Because of the thickness of this preparation, not all somatic cell nuclei are in focus. For this reason, many of them give a diffuse fluorescence image. Both photographs are at the same magnification. Scale bar = 50 jim. disappears in mature gonads; I have not seen this cell type. The full-grown oocytes form a polarized epithelium within the ovary. The germinal vesicle is located in the region of each oocyte that faces the coelomic space of the gonad, and the envelope that surrounds the oocytes is always thinnest on the opposite side of the oocyte facing the interior of the gonad (see a in Fig. 2B). If one attempts to obtain oocytes by mechanically ma- cerating the ovary, virtually all the oocytes are physically damaged: the envelope that surrounds the oocyte tears at the site where it is thinnest, and cytoplasm leaks out. In- tact, undamaged oocytes can be obtained by washing and incubating pieces of ovary in several changes of calcium- free seawater (see Materials and Methods). Under these conditions, the follicular epithelium around the oocyte retracts, and the oocytes can be dissociated from the ovary. Oocytes obtained in this manner do not have follicle cells on their surface; this point was checked by staining fixed oocytes with DAPI. These follicle-cell-free oocytes still have an extracellular envelope with microvilli extending into the envelope. If these oocytes are cultured in PSW for up to 8 h, the germinal vesicle remains intact. When. Figure 2. (A) Cross-section through two ovarian lobes at low magnification. The germinal
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
