Alkaline phosphatase activities with differential response to environmental salinity in muscle of Chasmagnathus granulata and Cyrtograpsus angulatus from Mar chiquita coastal lagoon.

PINONI, S.; LOPEZ MAÑANES, A.A.

Rosario, Argentina

Congreso; XXIII Annual Meeting Rosario Biology Society.; 2004

Sociedad de Biología de Rosario

Nota: El año de la reunión fue 2003. El sistema no me permitió poner la fecha correcta. Alkaline phosphatase (AP) has been little studied in decapod crustaceans. The aims of  this work were: a) to characterizate AP activity in muscle of Chasmagnuthus granulata, b) to study the long-term response to environmental salinity (S) of AP activity in muscle of C. granulata and Cyrtograpsus angulatus. Male adults crabs were acclimated for at least 18 days to 35 or 10‰S. AP activity was determined in chela muscle  homogenates (0.25M Sucrose/0.5mM EGTA-Tris pH 7.4) by measuring pNPP hydrolisis (9.5mM) in the presence of  100mM Tris (pHs 8.0 and 9.0) with or without MgSO4. Three to 6 independent  experiments were carried out. ANOVA was used as statistical analysis (p<0.05). In C. granulata, AP activity (nmoles pNPxmin-1xmg prot-1) was detected at both salinities -Mg++ at pH8.0 (35‰S: 203±49, 10‰S: 371± 36) and 9,0 (35‰S: 314±13, 10‰S: 289±26). Activity +Mg++ at pH8.0 was higher (35‰S: 723±50 y 10‰S: 765±83) but not at pH 9.0. Acclimation to 10‰S only affected on AP at pH8.0 –Mg++. In C. angulatus, AP at pH8,0 + Mg++ (35‰S: 625±103, 10‰S: 572±49) and -Mg++ (35‰S: 185±58, 10‰S: 83±48) was not affected by acclimation to 10‰S. The results show the existence of AP activities in muscle of chela of both crabs with differential response to Mg++ and reduced salinity, suggesting its role in muscle mechanisms secondaries to osmoionoregulation.