Buscar
Mostrando ítems 1-10 de 184
Sperm competition and reproductive mode influence sperm dimensions and structure among snakes
(Wiley Blackwell Publishing, Inc, 2009-10)
The role of sperm competition in increasing sperm length is a controversial issue, because findings from different taxa seem contradictory. We present a comparative study of 25 species of snakes with different levels of ...
Physical and morphological characteristics of the first three jets of pêga jackasses sperm-rich fraction
(2016-01-01)
The first three jets of the sperm-rich fraction of Pêga jackasses were collected and assessed separately. Five fertile Pêga jackasses were used as semen donors and underwent fractionated semen collection, using an open ...
Variability in sperm form and function in the context of sperm competition risk in two Tupinambis lizards
(Wiley, 2014-10)
In polyandrous species, sperm morphometry and sperm velocity are under strong sexual selection. Although several hypotheses have been proposed to explain the role of sperm competition in sperm trait variation, this aspect ...
Tales of the Tail and Sperm Head Aches : Changing concepts on the prognostic significance of sperm pathologies affecting the head, neck and tail
(Shanghai Institute of Materia Medica, 2012-01)
This article presents an update on the variable prognostic significance of different sperm pathologies in patients with severe male factor infertility due to morphology and motility disorders. Severe asthenozoospermia is ...
Blood and seminal plasma concentrations of selenium, zinc and testosterone and their relationship to sperm quality and testicular biometry in domestic cats
(Elsevier B.V., 2014-11-10)
The aim of this study was to assess seminal plasma (SP) and serum concentrations of zinc (Zn), selenium (Se) and testosterone (T) in domestic cats and determine whether these are related to sperm quality and testicular ...
Cytoplasmic droplet acting as a mitochondrial modulator during sperm maturation in dogs
(2017-06-01)
Motility acquisition during sperm maturation and passage through the epididymis is closely related to mitochondrial function and appears to occur in parallel with cytoplasmic droplet (CD) migration. However, such mechanism ...
Calcineurin Regulates Progressive Motility Activation of Rhinella (Bufo) arenarum Sperm Through Dephosphorylation of PKC Substrates
(Wiley, 2014-10)
Animals with external fertilization, as amphibians, store their sperm in a quiescent state in the testis. When spermatozoa are released into natural fertilization media, the hypotonic shock triggers activation of sperm ...