(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.
Zoosperm
Definition:
(n.) One of the spermatic particles; spermatozoid.