(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.
Spermatozoon
Definition:
(n.) Same as Spermatozoid.
Example Sentences:
(1) The relation of these layers to the movements of the spermatozoon, to the activation of the egg, to the block to polyspermy, and to each other are discussed.
(2) 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).
(3) The bitterling spermatozoon has been examined by electron microscopy using sectioned material and freeze-fracture replicas.
(4) Morphology of the mature spermatozoon is modified from that of the classic primitive or ect-aquasperm type by having 1) the acrosome embedded in the nucleus (the only known example within the Mollusca), 2) a deep basal invagination in the nucleus containing proximal and distal centrioles and an enveloping matrix (derived from the rootlet), 3) laterally displaced periaxonemal mitochondria, and 4) a tail extending from the basal invagination of the nucleus.
(5) The spermatozoon of the mealybug Pseudococcus obscurus Essig is a filamentous cell (0.25 micro by 300 micro) which exhibits three-dimensional flagellations throughout most of its length.
(6) Although zinc is required in seminal plasma for normal spermatozoon functionality, excessively high levels of this ion may be related with defective motility in asthenozoospermia samples.
(7) In contrast to all other polyopisthocotylean monogeneans in which the spermatozoa show an homogeneous biflagellate structure, the spermatozoon of Diplozoon is aflagellate.
(8) A cutoff point of one spermatozoon exhibiting sluggish motility per HPF was the most effective method of classifying the results of the postcoital test (X2(1) = 4.28, P = 0.037, RR = 4.7.
(9) The ultrastructural events of spermiogenesis and the ultrastructure of the mature spermatozoon of an acanthocotylid monogenean, Acanthocotyle lobianchi, are described.
(10) Spermatogenesis and the fine structure of the mature spermatozoon of Fasciola hepatica have been studied by transmission electron microscopy.
(11) To investigate the surface of the mammalian spermatozoon during its maturation in the epididymis, seven monoclonal antibodies were raised in mice against intact spermatozoa (and isolated sperm heads) recovered from the cauda epididymis of the golden hamster.
(12) The microtubules run parallel to the long axis of the spermatozoon and are arranged in a spiral pattern as seen in transection.
(13) The extreme morphological complexity of the Dina spermatozoon is related to the peculiar hypodermal fertilization which characterizes the erpobdellid family.
(14) Spermatozoal zinc is suggested to protect an inherent capacity for decondensation, thereby helping to extend the functional life-span of the ejaculated spermatozoon.
(15) In the spermatozoon the density of intramembranous particles was higher on the P- than on the E-fracture face of the plasma membrane.
(16) The spermatozoon shows a lack of acrosome as in many other teleosts previously studied.
(17) The comparative study of morphological anomalies of spermatozoon before and after penetration shows that in vivo or in vitro migration causes a selection of the spermatozoon.
(18) After getting treatment with methyltestosterone, the testis of those patients could grow larger but could not produce spermatozoon.
(19) At the junction of the two arms, where the arms join, the articular fossa receives the capitulum of the connecting piece which attaches the head of the spermatozoon to the tail.
(20) The stallion spermatozoon has many features in common with that of other mammals but differs specifically in that it has an asymmetric head, an abaxial position of the tail and an acrosome of small volume.