Osmotic regulation of free amino acid for adaptation to high salt in razor clam

Abstract

Free amino acids play an important role in osmotic regulation induced by high salt. In order to study the effect of free amino acids on the osmotic regulation of Sinonvacula constricta cells, the salinity was set at 20 and 32 in control group and experimental group. In the experimental group, proline, taurine and alanine amino acid solid powder with concentration of 5ug/ml was added. Serum and cell samples were taken from each group at different time points for detection by osmotic pressure and detection by flow cytometry. In summary, we found that serum osmolality, total free amino acid and single free amino acid content increased with the increase of salt stress, and remained at a high level. Under high salt conditions, the osmotic pressure in S. constricta could not equilibrate with the seawater environment. In the later stages of stress, the gap between the two gradually widened. Under the condition of amino acid addition, the osmotic pressure is gradually the same as that of foreign seawater. Furthermore, the mean number of fluorescent channels produced by high salt downflow cytometry was significantly lower than that of the other amino acid groups. Among the three amino acids, proline has the largest accumulation in the S. constrictaand the shortest regulation time for osmotic balance. It has been shown that free amino acids can help better osmotic regulation of hypersaline S. constricta. The results of this study provide a reference for exploring the physiological mechanism of the amino acid on salt tolerance in bivalves.