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Nucleotide content, oxydative phosphorylation, morphology, and fertilizing capacity of turbot ( Psetta maxima ) spermatozoa during the motility period
Author(s) -
Dreanno Catherine,
Cosson Jacky,
Suquet Marc,
Seguin Francois,
Dorange Germaine,
Billard Roland
Publication year - 1999
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/(sici)1098-2795(199906)53:2<230::aid-mrd12>3.0.co;2-h
Subject(s) - biology , motility , oligomycin , adenylate kinase , sperm , phosphomonoesters , biochemistry , oxidative phosphorylation , respiration , atpase , ouabain , sperm motility , intracellular ph , nigericin , intracellular , microbiology and biotechnology , phosphate , anatomy , enzyme , chemistry , botany , organic chemistry , sodium , inorganic phosphate , membrane
The interdependence between motility, respiration, ATP production, and utilization was investigated in intact spermatozoa of turbot ( Psetta maxima ), a marine teleost. When spermatozoa were diluted in a hyperosmotic medium (>300 mOsmol/kg), they immediately became motile, and the intracellular concentration of ATP as well as the adenylate energy charge ratio dropped concomitant with the straight‐line velocity. The ADP and AMP levels increased from 1.4 to 8.0 nmole/10 8 cells and from 0.6 to 6.0 nmole/10 8 cells, respectively. Moreover, 31 P‐NMR spectra recorded prior to the swimming phase revealed the presence of phosphomonoesters (PMEs) and phosphodiesters (PDEs), intracellular inorganic phosphate (Pi), and phosphocreatine (PCr). At the end of the motility period, PCr, PDE, and PME decreased, while the Pi level increased markedly. Following initiation of motility, O 2 consumption of spermatozoa increased from 34.9 to 124.8 O 2 nmole/10 9 spermatozoa/min. FCCP, an uncoupler of oxydative phosphorylation, did not significantly affect the respiratory rate of motile spermatozoa. Ouabain, a specific inhibitor of (Na + /K + )/ATPase, slightly decreased the respiration rate of motile spermatozoa, indicating that the major part of ATP catabolism was linked to dynein ATPase. Inhibitors of the respiratory chain (KCN, NaN 3 , NaHCO 3 – , oligomycin) reduced sperm respiration, percentage of motile cells, velocity, and adenylate contents. Following the reactivation of motility of demembranated spermatozoa, KCN, NaN 3 , NaHCO 3 – altered the flagellar beat frequency, demonstrating that these respiratory inhibitors possess action sites other than mitochondria. Mitochondrial oxydative phosphorylation is highly requested to produce energy required during motion. Nevertheless it is insufficient to maintain endogenous ATP stores. A second phase of motility was induced by a transfer of exhausted spermatozoa into an ionic medium of low osmolality (200 mOsmol/kg) for 30 min. Spermatozoa, once reactivated in AM, recovered 55% of initial motility and 31% of initial fertilization rate. In hypo‐osmotic medium, mitochondrial oxydative phosphorylation also induced ATP regeneration. Following activation of movement, several morphological changes were observed in the mitochondria and the midpiece. Mol. Reprod. Dev. 53:230–243, 1999. © 1999 Wiley‐Liss, Inc.