Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Spermatozoa of the shrew Suncus murinus, a mammal with abdominal testes, exhibit four unusual features: a giant acrosome; a dorsoventral asymmetry of their spermiation; a dorsoventral asymmetry of their head surface character; and also apparent surface maturity as they enter the epididymis. A Sertoli cell-periacrosomal cisternal complex envelops the giant acrosome during spermatid maturation. Spermiation is heraled by asymmetrical disorganization of the subplasmalemmal components of this complex and is completed by retraction of the Sertoli cell from the ventral and then the dorsal face of the spermatid head. This sequence or release is correlated with an asynchronous acquisition of negative surface charges on the spermatid head-demonstrable on glutaraldehyde-stabilized cells by the binding at pH 1.8 of positively charged colloidal particles of ferric oxide. Mature epididymal spermatozoa exhibit an asymmetry in the patterns of distribution of bound colloid over the dorsal vs. ventral surfaces of the sperm head, as well as regional differences between the tail midpiece and principal piece. Surface distributions of anionic residues and lectin (Con A)-binding sites characteristic of mature Suncus spermatozoa are demonstrable within the testis, unlike the situation in most nannals where distinct modifications of the sperm surface occur during epididymal passage.
 ...
PMID:Asymmetry of spermiation and sperm surface charge patterns over the giant acrosome in the musk shrew Suncus murinus. 126 97

The transformation of hamster sperm motility during capacitation in vitro and during maturation in the caudal epididymis was analyzed and compared using videomicrography. Sperm recovered from the distal portion of the caudal epididymis, as well as ejaculated sperm recovered from the uterus exhibited low amplitude, planar flagellar beating. By 3 hr of incubation under capacitating conditions, the caudal epididymal sperm were swimming in helical patterns apparently produced by significantly increased acuteness of flagellar bending and by torsion seen as abrupt, periodic turning of the head. By 4 hr, most sperm were hyperactivated, swimming in circles resulting from asymmetrical, planar flagellar bending that was significantly more acute than the preceding patterns. When motility parameters of fresh sperm were compared with those of sperm swimming in the transitional helical pattern and with hyperactivated sperm, transitional sperm had significantly higher net and average path velocities than the others, indicating that they covered space at the greatest rate. This suggests that the transitional phase plays an important role in sperm transport. Sperm recovered from the proximal region of the caudal epididymis, near the corpus, swam in either the helical or hyperactivated patterns, or a mixture of the two. The means of their flagellar curvature ratios and linear indices were intermediate between helical and hyperactivated mean values. Thus, sperm undergoing final maturation in the caudal epididymis reverse the pattern of development of hyperactivation. Also, the development of hyperactivated motility must therefore entail induction of a preexisting potential for flagellar movement, rather than a maturational process.
 ...
PMID:Hamster sperm motility transformation during development of hyperactivation in vitro and epididymal maturation. 319 45

Spermatozoa of several mammalian species were studied by means of high-speed cinematography and electron microscopy. Three types of motile patterns were observed in mouse spermatozoa. The first type involved an asymmetrical beat which seemed to propel the sperm in circular paths. The second type involved rotation of the sperm and appeared to allow them to maintain straight paths. In the third type of pattern, the sperm appeared to move by crawling on surfaces in a snakelike manner. Spermatozoa of rabbit and Chinese hamster also had an asymmetrical beat which sometimes caused them to swim in circles. In spite of the asymmetry of the beat, these spermatozoa were also able to swim in straight paths by rotating around a central axis as they swam. Spermatozoa of some species appeared very flexible; their flagella formed arcs with a very small radius of curvature as they beat. Spermatozoa of other species appeared very stiff, and their flagella formed arcs with a very large radius of curvature. The stiffness of the spermatozoan appeared to correlate positively with the cross-sectional area of the dense fibers. This suggests that the dense fibers may be stiff elastic elements. Opossum sperm become paired as they pass through the epididymis. Pairs of opossum spermatozoa beat in a coordinated, alternating manner.
 ...
PMID:Comparative analysis of mammalian sperm motility. 502 10