The Australian saltwater crocodile (Crocodylus porosus) provides evidence that the capacitation of spermatozoa may extend beyond the mammalian lineage

Nixon, Brett, Anderson, Amanda L., Smith, Nathan D., McLeod, Robby and Johnston, Stephen D. (2016) The Australian saltwater crocodile (Crocodylus porosus) provides evidence that the capacitation of spermatozoa may extend beyond the mammalian lineage. Proceedings of the Royal Society B: Biological Sciences, 283 1830: . doi:10.1098/rspb.2016.0495


Author Nixon, Brett
Anderson, Amanda L.
Smith, Nathan D.
McLeod, Robby
Johnston, Stephen D.
Title The Australian saltwater crocodile (Crocodylus porosus) provides evidence that the capacitation of spermatozoa may extend beyond the mammalian lineage
Formatted title
The Australian saltwater crocodile (Crocodylus porosus) provides evidence that the capacitation of spermatozoa may extend beyond the mammalian lineage
Journal name Proceedings of the Royal Society B: Biological Sciences   Check publisher's open access policy
ISSN 1471-2954
0962-8452
Publication date 2016-05-11
Year available 2016
Sub-type Article (original research)
DOI 10.1098/rspb.2016.0495
Open Access Status Not Open Access
Volume 283
Issue 1830
Total pages 6
Place of publication London, United Kingdom
Publisher The Royal Society Publishing
Collection year 2017
Language eng
Abstract Although mammalian spermatozoa only acquire functional maturity as they are conveyed through the male (epididymal maturation) and female (capacitation) reproductive tracts, the degree of post-testicular development necessary to achieve fertilization in other vertebrate species remains far less clear. Indeed, despite reports that the epididymis of birds and reptiles is capable of secreting proteins that bind and modify the sperm surface characteristics, it remains unclear whether capacitation is a pre-requisite for fertilization in these species. Using the ancient reptilian Australian saltwater crocodile as a model, this study was undertaken to explore whether reptile sperm do undergo capacitation-like changes following ejaculation. Our studies revealed that crocodile spermatozoa experienced a rapid and sustained, cyclic-AMP mediated increase in progressive motility following incubation under conditions optimized for the induction of capacitation in mammalian species such as the mouse and human. This response was coupled with elevated levels of phosphorylation associated with both protein kinase A and tyrosine kinase substrates, the latter of which were predominantly localized within the sperm flagellum. In findings that also accord with mammalian spermatozoa, we confirmed a homologue of outer dense fibre 2 as one of the principal substrates for tyrosine phosphorylation. Overall, our findings support the concept that crocodile spermatozoa do undergo a process that is homologous to capacitation in preparation for fertilization of an ovum.
Keyword Capacitation
Crocodile
Fertilization
Spermatozoa
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Agriculture and Food Sciences
 
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