Compensatory adjustment in chloride cells during salinity adaptation in mud crab, Scylla serrata

Abstract

Capacity acclimation is a measurement of understanding the degree of adaptation that take place in physiological activities or biological functions in altered environmental conditions. Precht and Prosser in different ways classified capacity acclimation due to alterations of environmental temperature with respect to various physiological processes in a variety of organisms. We hypothesized that the same may be applied to understand the degree of adaptation in various physiological processes of organisms due to change in the salinity or any other environmental parameters. In order to understand the adaptive capability or the degree of compensation in different saline environment in some of the physiological processes of chloride cells, the chloride cells from 1 psu and or 35 psu acclimated crabs were cultured further in vitro, in L-15 media maintained with 12 psu salinity for another 5 h without any mortality. Rate of ion transport across the chloride cell membrane, and the activity of ion transporting enzyme were recorded. Over compensation or perfect compensation in the transport rate of K+, Na+ and Ca++ ions, due to hypo saline as well as hyper saline acclimation, clearly indicates their role in maintaining the homeostasis in osmoregulatory processes during salinity adaptation. On the other hand, inverse compensation or partial compensation in the transport rate of Cl- ions and the activity of ATPases indicate about their involvement in adjusting the osmoregulatory processes in altered saline environment rather that contributing to adaptability processes during change in the environmental salinity.