Euryhaline tilapia @entity13864 can reproduce in freshwater and in seawater. Regulation of sperm motility appears to be modulated during acclimation of the fish from freshwater to seawater, being independent of extracellular @entity141 in freshwater and dependent on extracellular @entity141 in seawater. In the presence of extracellular @entity141 , sperm of seawater-acclimated tilapia (SWT) showed motility even in a @entity4372 environment, whereas sperm of freshwater-acclimated tilapia (FWT) were not motile. The @entity141 indicator, @entity3576 , revealed that intracellular @entity141 concentration, [ @entity141 ]i, of SWT sperm increased only in the presence of extracellular @entity141 in @entity2421 or @entity4372 conditions. Since the increased [ @entity141 ]i in FWT sperm occurred under @entity2421 conditions via intracellular @entity141 stores, it is likely that tilapia modulate their source of increasing [ @entity141 ]i from intracellular stores (in FWT sperm) to extracellular stores (in SWT sperm). Experiments using demembranated sperm revealed that @entity141 is necessary for activation of motility, suggesting that @entity141 plays a key role in motility regulation in SWT sperm. We detected three phosphoproteins associated with the activation of sperm motility. @entity563 and @entity1889 residues of two proteins of 15 kDa and 18 kDa became @entity2421 but remained phosphorylated in @entity4372 conditions, suggesting that these protein phosphorylations were not only related to motility activation under @entity4372 conditions but also resistant to osmotic pressure. The @entity1889 residue(s) of a 41 kDa protein was also phosphorylated in dry sperm, even in FWT sperm in motility-feasible @entity2421 conditions. It is likely that acclimation of the motility apparatus is associated with modulation of the flow of @entity141 to increase [ @entity141 ]i and protein phosphorylation.

Acclimation of sperm motility apparatus in seawater-acclimated euryhaline tilapia XXXX .

@entity4372 :: ('MESH:D009122', 'Disease') :: ['hypertonic'] @entity563 :: ('CHEBI:17822', 'Chemical') :: ['Serine'] @entity3576 :: ('MESH:C059715', 'Chemical') :: ['fluo-3'] @entity2421 :: ('MESH:D009123', 'Disease') :: ['hypotonic', 'dephosphorylated in hypotonic conditions'] @entity13864 :: ('8127', 'Species') :: ['Oreochromis mossambicus'] @entity141 :: ('CHEBI:29108', 'Chemical') :: ['Ca2+', 'Ca(2+)'] @entity1889 :: ('CHEBI:26986', 'Chemical') :: ['threonine']
@entity13864 :: (8127,Species) :: ['Oreochromis mossambicus']
