Involvement of Mitochondrial Activity and OXPHOS in ATP Synthesis During the Motility Phase of Spermatozoa in the Pacific Oyster, Crassostrea gigas
|Author(s)||Boulais Myrina1, Soudant Philippe2, Le Goic Nelly2, Quere Claudie3, Boudry Pierre3, Suquet Marc1|
|Affiliation(s)||1 : IFREMER, UMR LEMAR 6539, UBO CNRS IRD, Stn Expt Argenton, F-29840 Landunvez, France.
2 : Univ Bretagne Occidentale, IFREMER, UBO CNRS IRD, IUEM,UMR LEMAR 6539, Plouzane, France.
3 : IFREMER, Ctr Bretagne, UMR LEMAR 6539, UBO CNRS IRD, Plouzane, France.
|Source||Biology Of Reproduction (0006-3363) (Soc Study Reproduction), 2015-11 , Vol. 93 , N. 5|
|WOS© Times Cited||23|
|Keyword(s)||Crassostrea gigas, intracellular ATP content, mitochondrial membrane potential, oxidative phosphorylation, sperm motility|
|Abstract||In the Pacific oyster, spermatozoa are characterized by a remarkably long movement phase (i.e., over 24 h) sustained by a capacity to maintain intracellular ATP level. To gain information on oxidative phosphorylation (OXPHOS) functionality during the motility phase of Pacific oyster spermatozoa, we studied 1) changes in spermatozoal mitochondrial activity, that is, mitochondrial membrane potential (MMP), and intracellular ATP content in relation to motion parameters and 2) the involvement of OXPHOS for spermatozoal movement using carbonyl cyanide m-chlorophenyl hydrazone (CCCP). The percentage of motile spermatozoa decreased over a 24 h movement period. MMP increased steadily during the first 9 h of the movement phase and was subsequently maintained at a constant level. Conversely, spermatozoal ATP content decreased steadily during the first 9 h postactivation and was maintained at this level during the following hours of the movement phase. When OXPHOS was decoupled by CCCP, the movement of spermatozoa was maintained 2 h and totally stopped after 4 h of incubation, whereas spermatozoa were still motile in the control after 4 h. Our results suggest that the ATP sustaining flagellar movement of spermatozoa may partially originate from glycolysis or from mobilization of stored ATP or from potential phosphagens during the first 2 h of movement as deduced by the decoupling by CCCP of OXPHOS. However, OXPHOS is required to sustain the long motility phase of Pacific oyster spermatozoa. In addition, spermatozoa may hydrolyze intracellular ATP content during the early part of the movement phase, stimulating mitochondrial activity. This stimulation seems to be involved in sustaining a high ATP level until the end of the motility phase.|