(1) Diplotene spermatocytes have the largest nuclei of all germ cells.
(2) X and Y chromosomes were paired in 14.5% of the diakinesis-MI spermatocytes that contained a Y chromosome.
(3) The ultrastructural study of nucleoli and ribonucleoprotein-containing structures in human seminiferous tubules revealed that the nucleoli of spermatogonia, spermatocytes and Sertoli cells exhibited a tripartite structure consisting of: a fibrillar center, a compact granular portion, and a reticular portion containing both pars fibrosa and pars granulosa.
(4) The pachytene behavior of the chromosomes of Microtus agrestis (L.) (Rodentia, Arvicolidae) males carrying either the standard, or the pericentrically inverted Lund Y chromosome have been examined by electron microscopy of microspread spermatocytes.
(5) Immunoelectron microscopy revealed that in spermatogonia, leptotene and pachtyene spermatocytes, and in Golgi phase spermatids, B23 and nucleolin were localized in the dense fibrillar component and granular component of the nucleolus but not in the fibrillar centers.
(6) In addition, there is significantly less germ cell production from the primary spermatocyte stage of spermatogenesis onwards and the total number of Sertoli cells observed is less.
(7) The low mitotic index of type A0 spermatogonia (0.1%) indicated that these cells were not actively involved in the production of spermatogonia or spermatocytes during each cycle of the seminiferous epithelium and thus were considered as reserve stem cells.
(8) In meiotic prophase of spermatocytes, chromosomes 2 and 3 form pachytene-diplotene bivalents whose arms may be associated by chiasmata in postdiplotene stages, but the X, Y and fourth chromosomes participate in a complex multivalent.
(9) In the absence of somatic cells, their maximal viability is approximately 5 days, whereas spermatocytes adhering to Sertoli cells can survive at least 10-12 days, provided trout lipoproteins are present.
(10) The nuclear envelope of growing postpachytene spermatocyte I differs notably in structure between the fleabeetles Omophoita cyanipennis and Oedionychus bicolor.
(11) However, the major thermal transitions for chromatin from mid-spermatids are much lower than those from pachytene spermatocytes and early-spermatids.
(12) Degenerating germ cells were not detected at stages II-VI, and only rarely at stage VII (n = 366 tubules) in which one primary spermatocyte and one step 19 spermatid degenerated.
(13) This stimulatory effect of pachytene spermatocyte protein was domain specific from the apical surface of Sertoli cells, and seemed specific for secretion because total intracellular protein did not increase under the influence of pachytene spermatocyte protein.
(14) Dissociation of the X-Y chromosome bivalent in diakinesis-metaphase I spermatocytes of adult mice was significantly more frequent in the CBA strain (29%) than in C57, KP, or KE strains (7-11%).
(15) Sertoli cells were stimulated and pachytene spermatocytes were numerous.
(16) In P. ivoriensis the secondary spermatocytes were separated by interspaces between the irregularly shaped cell surfaces.
(17) In infants and children, yolk sac tumor and teratoma are the usual tumors; in older age patients, it is predominantly spermatocytic seminoma and malignant lymphoma, although the others may occur as well.
(18) Differences in content of total phospholipids, individual classes of phospholipids and triacylglycerols among spermatocytes, spermatids and late spermatids were also observed.
(19) While in the testis the spermatocytes were shown to contain both enzymes and their transcripts, in other types of cells this could not be observed.
(20) The effects of nitrofurantoin [N-(5-nitro-2-furfurylidine)-1-amino-hydantoin] on chromosomes of primary and secondary spermatocytes of mice were studied.
Spermatogonium
Definition:
(n.) A primitive seminal cell, occuring in masses in the seminal tubules. It divides into a mass (spermosphere) of small cells (spermoblast), which in turn give rise to spermatozoids.
Example Sentences:
(1) An Ap1 spermatogonium produces two Ap2 spermatogonia during Stage II of the cycle, Ap2 spermatogonia produce four type B spermatogonia during Stage VI of the cycle, and type B spermatogonia produce eight primary spermatocytes during Stage III of the cycle.
(2) These data suggest that the cell(s) of the seminiferous tubule involved in FSH regulation must be either the type A spermatogonium or the Sertoli cell.
(3) The relative amount of DNA in a somatic cell to that in a spermatogonium averaged 79.2%.
(4) Additionally it also inhibits the process of spermatogonium multiplication in the testis and of the progesterone multiplication in the ovary.
(5) The intermediate spermatogonium contins an ovoid nucleus characterized by one or two nuclei and heterochromatin scattered in the nuceoplasm.
(6) In the basal third of the Sertoli cell, membranous segments that faced a spermatogonium or a migrating spermatocyte displayed forming tight, gap, and adherens junctions.
(7) This finding was interpreted as the result of a single act of non-disjunction taking place in a spermatogonium.
(8) Testosterone bound to target cells initiates their division and decreases duration of spermatogonium mitosis block and delay in primary spermatocyte development increasing the number of germ cells.
(9) In some of the animals, a few isolated seminiferous tubules contained an occasional spermatogonium or primary spermatocyte.
(10) a single spermatogonium gives rise to 32 spermatozoa.
(11) The administration of exogenous testosterone was shown to stimulate DNA synthesis, inhibited by the effect of radiation, in spermatogonium populations of A1-4, intermediate, and B types, and in preleptotene primary spermatocytes; RNA synthesis was increased in the same populations of spermatogonia and pachytene primary spermatocytes.
(12) Each divides to produce a new Ad spermatogonium and a Ap1 spermatogonium during Stage IX of the cycle of the seminiferous epithelium.
(13) Repopulating spermatogenic colonies, found in the seminiferous epithelium after irradiation with fast-fission neutrons, were studied to determine the chance that a stem cell Asingle (As) spermatogonium would complete a self-renewing division (P).
(14) A preliminary report on the selective effect of Vinca rosea L. alkaloids on Type A4 rat spermatogonium is presented.
(15) The nucleus of the type "B" spermatogonium is more spherically shaped with a centrally placed nucleolus and heterochromatin associated with the nuclear envelope.
(16) The type "A" spermatogonium contains an oblong nucleus with one or two shallow infoldings of the nuclear membrane.
(17) Consequently, 32 spermatids can result from each division of an Ad spermatogonium.
(18) Various premeiotic and meiotic stages, from spermatogonium A and B to metaphase 1, were identified in the bull ejaculates.
(19) Pathological and electron microscopic examinations indicated that spermatogenic cells were damaged by MeHg especially spermatogonium and spermatocyte.
(20) Histological examination of rat testis, revealed that the spermatogenesis is arrested at spermatogonium stage in rats fed on protein free diet, and at primary and secondary spermatocyte stage in rats fed on normal but reduced diet.