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Articles by Nathan Tholl in JoVE
JoVE General
Dois tipos de ensaios para detecção de quimiotaxia Sapo Sperm
1Department of Animal Sciences, University of Illinois, Urbana-Champaign, 2School of Life Sciences, Arizona State University
Ovos e os revestimentos extracelular em torno de ovos com freqüência liberação de peptídeos, proteínas e pequenas moléculas que se comunicam com o esperma para guiá-los até o óvulo, promovendo assim a fecundação. Usando o esperma de rã que descrever e comparar duas classes de testes usados para detectar quimiotaxia esperma - ensaios de esperma acumulação e ensaios de monitoramento de esperma.
Other articles by Nathan Tholl on PubMed
Swimming of Xenopus Laevis Sperm Exhibits Multiple Gears and Its Duration is Extended by Egg Jelly Constituents
The motility of Xenopus sperm is initiated by the osmotic shock experienced when these cells are ejaculated into low-salinity pond water. Motility is brief and is required for the sperm to penetrate the jelly layers and fertilize the egg. In this study we demonstrate that extracts of egg jelly contain factors that extend the period of sperm motility as well as providing a chemoattractant activity as previously reported. Both activities are partially dependent on extracellular calcium. Time-lapse and video microscopy show that after activation of motility the number of motile sperm decreases rapidly, with a half-time of about 2 min. Addition of 10% v/v egg jelly extract ("egg water") increased the number of motile sperm 2-fold over controls at 20 s and about 4- to 10-fold over controls at 10 min after initiation of motility. Extension of motility lifetime was not mediated by a nonspecific protein or by allurin, the egg-water protein that has chemoattractant activity. The helical path of Xenopus sperm exhibited tight coupling between rotational and forward velocities in egg jelly, but coupling changed rapidly from moment to moment in low-salinity buffer. Our observations suggest that jelly-derived factors regulate both the longevity and directionality of sperm propulsion.
