(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.
Spermatozoa
Definition:
(pl. ) of Spermatozoon
Example Sentences:
(1) The proportion of motile spermatozoa decreased with time at the same rate when samples were prepared in either HEPES or phosphate buffers.
(2) Females were killed at various times after the onset of mating or artificial insemination, oviducts were fixed and sectioned serially, and spermatozoa were counted individually as to their location in the oviduct.
(3) The sensitivity of ejaculated spermatozoa to ouabain (in inhibitor of Na+-K+ ATPase) was determined on 4 consecutive weeks in November, March-April, and July-August.
(4) Spontaneous lipid peroxidation in washed human spermatozoa was induced by aerobic incubation at 32 C and measured by malonaldehyde production; loss of motility during the incubation was determined simultaneously.
(5) The same ratio occurred when zinc (0 to 0.6 mM in citrate buffer) was added to semen or washed spermatozoa.
(6) The sulfhydryl group content of rat epididymal spermatozoa was similar from one cell to another, suggesting little sperm reabsorption in the epididymis.
(7) Hexa- and octasaccharides induced a slight increase in the number of acrosome reacted spermatozoa and disaccharides were ineffective.
(8) In human spermatozoa, the outer acrosomal membrane and plasma membrane contained both types of plasminogen activator (t-PA and u-PA); in addition, t-PA antigen was measured.
(9) To analyze the acrosome reaction induced by the PL, washed or diluted spermatozoa were incubated with or without a PL suspension at 39 C or 41 C. In spermatozoa incubated with the PL suspension, the percentage of spermatozoa lacking acrosomal caps was significantly greater than in controls (without PL).
(10) The migration of human spermatozoa in cervical mucus obtained from women shortly before mid-cycle was studied, using an in-vitro method for horizontal sperm penetration.
(11) The effect of alpha-chlorohydrin on the metabolism of glycolytic and tricarboxylate-cycle substrates by ram spermatozoa was investigated.
(12) Oocytes and spermatozoa are not attacked by the HIV virus but associated lymphocytes or monocytes may be infected.
(13) Three simple equations were determined, by means of which each laboratory will be able to standardize their subject scale for forward progression of the spermatozoa.
(14) The nuclei were isolated from boar spermatid or sperm cells at three distinct stages of spermatogenesis: just before the completion of a maturation process in the testis (late spermatid), immediately after a subsequent transformation into spermatozoa (caput spermatozoon), and after full maturation (cauda spermatozoon).
(15) Cytogenetic analysis revealed hyperhaploid (2.5%) and hypohaploid spermatozoa (1.9%).
(16) Temperature decline through the region of 10 degrees C caused a number of spermatozoa in buffer to undergo a sudden asymmetric bending of the flagellum in the region of the midpiece.
(17) The effect of different lipids on the fertilizing capacity of Bufo arenarum spermatozoa and on acrosome breakdown of Leptodactylus chaquensis spermatozoa was studied.
(18) More spermatozoa were affected and died more quickly as the concentration of D2O increased.
(19) Indirect immunofluorescence studies with four monoclonal antibodies raised against carp spermatozoa revealed that monoclonal antibody WCS 29 stained the outer membranes of primordial germ cells in larvae from 3 days after fertilization.
(20) Neither pH nor composition of liner collection cone had an effect on postthaw acrosomal scores, but the time required for a 50% increase in severely damaged acrosomes was greater for spermatozoa collected in polyethylene than in rubber liner collection cones.