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Helfenstein, Fabrice
Nom
Helfenstein, Fabrice
Affiliation principale
Fonction
Professeur assistant FNS
Email
fabrice.helfenstein@unine.ch
Identifiants
Résultat de la recherche
Voici les éléments 1 - 10 sur 39
- PublicationMétadonnées seulementFemale choice of young sperm in a genetically monogamous bird(2004)
;Wagner, Richard H.; Danchin, Etienne - PublicationMétadonnées seulementImmune activation reduces sperm quality in the great tit(2011)
;Losdat, Sylvain ;Richner, Heinz ;Blount, Jonathan D. - PublicationMétadonnées seulementLow frequency of extra-pair paternity and high frequency of adoption in black-legged kittiwakes(2004)
; ;Tirard, Claire ;Danchin, EtienneWagner, Richard H. - PublicationMétadonnées seulementFemales of carotenoid-supplemented males are more faithful and produce higher quality offspring(2008)
; ;Losdat, Sylvain ;Saladin, VerenaRichner, Heinz - PublicationMétadonnées seulementHigher in vitro resistance to oxidative stress in extra?pair offspring(2011)
;Losdat, Sylvain; ;Saladin, VerenaRichner, Heinz - PublicationMétadonnées seulementResistance to oxidative stress shows low heritability and high common environmental variance in a wild bird(2014)
;Losdat, Sylvain; ;Blount, Jonathan D.Richner, Heinz - PublicationMétadonnées seulementPolymorphic microsatellites in the black?legged kittiwake Rissa tridactyla(2002)
;Tirard, Claire; Danchin, Etienne - PublicationMétadonnées seulementReproductive effort transiently reduces antioxidant capacity in a wild bird(2011)
;Losdat, Sylvain; ;Gaude, BenoîtRichner, Heinz - PublicationMétadonnées seulementElectroejaculation and semen buffer evaluation in the microbat Carollia perspicillata(2015-3-1)
;Fasel, Nicolas Jean; ;Buff, SamuelRichner, HeinzScientific interests and conservation needs currently stress the necessity to better understanding bat reproductive biology. In this study, we present the first, safe, inexpensive, and reliable method to obtain sperm from a microbat species (Carollia perspicillata) by electroejaculation. This method revealed to be highly efficient (100% success rate). We obtained ejaculates composed of two characteristically different fractions. We compared three buffers and recommend using an Earle's balanced salt solution as a semen extender. Earle's balanced salt solution provided significant repeatable measure of swimming ability (intraclass correlation coefficient: 0.74, P < 0.01) and proportion of motile sperms (intraclass correlation coefficient: 0.08, P = 0.01) and allowed sperm to maintain optimal swimming capacity over time. None of the buffers could dissolve all the coagulated sperm. Although the trypsin buffer freed a larger fraction of spermatozoa in the ejaculate, it impaired swimming ability without improving motility, viability, and stamina. We thus argue that the sperm population analyzed with Earle's balanced salt solution is a representative of the ejaculate. Finally, we found that the mean sperm velocity of C perspicillata (78.8 μm/s) is lower than that predicted by regressing sperm velocity on relative testes mass, a proxy of sperm competition. The question as to whether C perspicillata is an outsider for sperm velocity, or whether bats evolved yet another unique mechanism to cope with sperm competition deserves more investigations. - PublicationMétadonnées seulementEditorial: oxidative stress and signal honesty(2017-4-24)
;Costantini, David