<i>Xenopus laevis</i> fertilisation: analysis of sperm motility in egg jelly using video light microscopy

Reinhart, Donnie; Ridgway, James; Chandler, Douglas E.

doi:10.1017/s0967199498000100

Cited by 30 publications

(19 citation statements)

References 19 publications

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“…A detailed published study of fertilisation of X. laevis, suggests the jelly coat is penetrated optimally by sperm in 40 mM NaCl, when sperm motility is relatively long lived (Hollinger, 1980;Reinhart et al, 1998). However, in our hands fertilisation efficiency was not significantly different over the range of MMR concentration 4 -40 mM (Fig.…”

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confidence: 45%

Cryopreservation of sperm ofXenopus laevis andXenopus tropicalis

Sargent

Mohun

2005

genesis

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Now that transgenic strains of Xenopus laevis and X. tropicalis can be generated efficiently and with genomic sequence resources available for X. tropicalis, early amphibian development can be studied using integrated biochemical and genetic approaches. However, housing large numbers of animals generated during genetic screens or produced as novel transgenic lines presents a considerable challenge. We describe a method for cryopreserving Xenopus sperm that should facilitate low maintenance, long-term storage of male gametes. By optimising the cryoprotectant, the rates of cooling and thawing, and conditions for fertilisation, sperm from the equivalent of one-eighth of a X. laevis testis or of two X. tropicalis testes have been cryopreserved and used to fertilise eggs of both species after thawing. Sperm undergo a substantial loss of viability during a freeze-thaw cycle, but sufficient survive to fertilise eggs. Gametes of mutagenised frogs are being stored in connection with a screen for developmental mutations.

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confidence: 45%

Cryopreservation of sperm ofXenopus laevis andXenopus tropicalis

Sargent

Mohun

2005

genesis

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“…Rather, sperm must traverse several viscous jelly coats before they come into contact with the egg. In Xenopus, it was shown that up to 50 per cent of the sperm take indirect, energy-wasting routes and become trapped within the jelly layers (Reinhart et al 1998). Those that are successful in reaching the egg appear to exhibit fewer instances of stopping and starting, suggesting that successful sperm are those that exhibit sustained levels of motility (Reinhart et al 1998).…”

Section: Discussionmentioning

confidence: 99%

“…In Xenopus, it was shown that up to 50 per cent of the sperm take indirect, energy-wasting routes and become trapped within the jelly layers (Reinhart et al 1998). Those that are successful in reaching the egg appear to exhibit fewer instances of stopping and starting, suggesting that successful sperm are those that exhibit sustained levels of motility (Reinhart et al 1998). Our competitive fertilization trials suggest that in frogs, selection acts for slow and steady swimming performance, a selection pressure that may underlie the evolution of the unusual sperm form and function that is characteristic of frogs.…”

Section: Discussionmentioning

confidence: 99%

Sperm competitiveness in frogs: slow and steady wins the race

et al. 2009

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When sperm compete to fertilize available ova, selection is expected to favour ejaculate traits that contribute to a male's fertilization success. While there is much evidence to show that selection favours increased numbers of sperm, only a handful of empirical studies have examined how variation in sperm form and function contributes to competitive fertilization success. Here, we examine selection acting on sperm form and function in the externally fertilizing myobatrachid frog, Crinia georgiana. Using in vitro fertilization techniques and controlling for variation in the number of sperm contributed by males in competitive situations, we show that males with a greater proportion of motile sperm, and motile sperm with slower swimming velocities, have an advantage when competing for fertilizations. Sperm morphology and the degree of genetic similarity between putative sires and the female had no influence on competitive fertilization success. These unusual patterns of selection might explain why frog sperm typically exhibit relatively slow swimming speeds and sustained longevity.

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“…Based on measurements of protein efflux from jelly (36) and on measurements of chemoattractant activity in the medium (J.O., unpublished observations), we estimate that 50% of the allurin present in the egg jelly layers is released into the medium within 5 min after spawning. Thus, Xenopus sperm deposited onto the egg mass are exposed immediately to this chemoattractant, a mechanism that may serve to direct sperm to the egg surface at the beginning of a relatively short (15 min) lifespan (44,45).…”

Section: Discussionmentioning

confidence: 99%

Allurin, a 21-kDa sperm chemoattractant from Xenopus egg jelly, is related to mammalian sperm-binding proteins

Olson

Xiang

Ziegert

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

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119

111

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Previously, we demonstrated that a protein from Xenopus egg jelly exhibits sperm chemoattractant activity when assayed by either video microscopy or by sperm passage across a porous filter. Here we describe the isolation and purification of allurin, the protein responsible for this activity. Freshly oviposited jellied eggs were soaked in buffer, and the conditioned medium was loaded onto an anion exchange column and eluted with an NaCl gradient. The active fraction was purified further by RP-HPLC, the chemoattractant protein appearing as a single sharp peak. The amino acid sequence of the protein, determined by direct sequencing and cloning of cDNAs coding for the protein, consisted of 184 amino acids having a molecular mass of 21,073 Da. The protein shares homology with the mammalian cysteine-rich secretory protein (CRISP) family that includes testes-specific spermatocyte protein 1, a cell adhesion protein which links spermatocytes to Seritoli cells, and acidic epididymal glycoproteins that bind to sperm and have been implicated in sperm-egg fusion. Phylogenetic analysis suggests that allurin evolved from the ancestral protein that gave rise to the mammalian CRISP family. Addition of allurin to this family portends that the CRISP family represents a group of ''sperm escort'' proteins, which bind to sperm at various steps in their life history, facilitating passage from one functional stage to the next. Allurin stands out in this regard, representing both the first vertebrate sperm chemoattractant to be purified and sequenced and the first member of the CRISP family to be found in the female reproductive tract. sperm chemotaxis ͉ fertilization ͉ TPX-1 ͉ AEG ͉ CRISP

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Xenopus laevis fertilisation: analysis of sperm motility in egg jelly using video light microscopy

Cited by 30 publications

References 19 publications

Cryopreservation of sperm ofXenopus laevis andXenopus tropicalis

Cryopreservation of sperm ofXenopus laevis andXenopus tropicalis

Sperm competitiveness in frogs: slow and steady wins the race

Allurin, a 21-kDa sperm chemoattractant from Xenopus egg jelly, is related to mammalian sperm-binding proteins

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