Nitric oxide (NO) is a highly reactive, labile gas produced by the enzymatic conversion of L-arginine by nitric oxide synthases NOS. In mammals, NO mediates multiple physiological processes from cardiovascular control...
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Nitric oxide (NO) is a highly reactive, labile gas produced by the enzymatic conversion of L-arginine by nitric oxide synthases NOS. In mammals, NO mediates multiple physiological processes from cardiovascular control to neural transmission. Three NOS isoforms neuronal, inducible and endothelial have been cloned, sequenced and characterized from several mammalian species. nNOS isoforms were characterized from adult grouper (Epinephelus coioides) by using RT-PCR with degenerate oligonucleotide primers designed against a portion of the mammalian NOS gene that codes for the calmodulin -binding region, this region was chosen because it is highly conserved among NOS sequences to date and is a functionally important region of NOS proteins. A partial gene sequence of 377 bp corresponding to mammalian nNOS is obtained. This sequence showed 82%-83%, 85%-93% homogeneity with that of mammalian and the other fish respectively. The deduced amino acid of *** shows high identity with that of mammalian (92%-93%), and the other fish (93%-99%). Phylogenetic analysis of these sequences confirms the conserved nature of NOS, particularly of the calmodulin-binding domains.
The effect were examined in vitro of the ionic composition of the incubation medium on the acquisition and loss of the potential for motility were exammined by the spermatozoa of the Japanese eel （Anguilla japonica）...
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The effect were examined in vitro of the ionic composition of the incubation medium on the acquisition and loss of the potential for motility were exammined by the spermatozoa of the Japanese eel （Anguilla japonica）. Milt was obtained from male eels that had been artificially matured by repeated injections of HCG. The percent motility increased with increasing concentrations of Na+、K+、Ca2+ and Mg2+ ions (0-400mmol·L-1) and decreased with concentrations of those ions(500-1000 mmol·L-1), eel sperm was collected and then incubated with nitric oxide donor-sodium nitroprusside in different doses. Eel sperm motility was accelerated or maintained at low dose of sodium nitroprusside （SNP） (10-10-10-6 mol·L-1), while marked inhibition effects were found at high dose (SNP>10-5mol·L-1). Nitric oxide affects the motility of eel sperm in dose-dependent manner. The eel sperm of maturation by SPN and HCG was used for fertilizing three batches of eggs and hatchability is higher than the sperm of maturation by HCG.
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