LIPOPEROXIDATION, PHENOLIC COMPOUNDS, ENDOPHENOL OXIDASE ENZYME AND PROTEIN METABOLISM IN KIRCHNERELLA LUNARIS CULTURES GROWN UNDER SALINITY

This work was conducted to study the effect of salinity treatments on growth and metabolism of the green micro-alga Kirchneriella lunaris (Selenastraceae, Chlorophyta) isolated from sewage water treatment plant at El-Kola , Sohag district, Egypt. The levels of salinity used were 00, 50, 100, 150, 200, 250 and 300 mM. NaCl. The test organism was left to grow for 10 days under the various salinity levels. Dry mass and photosynthetic pigments were increased at the level of 50 mM NaCl,. These values were decreased at the higher concentrations of NaC l in the culture media. Phenolic compounds content was reduced at 50 mM NaCl, and then increased significantly with increasing the dose of sodium chloride. Malondialdehyde (MDA) contents were elevated at all salinity concentrations. Salinity increased the intensity and the number of isoenzyme forms of indophenol oxidase (IPOX) which represents an increase in enzyme expression and activity. All concentrations of salt used stimulated the production of proteins (soluble and insoluble and total. Salinity induced the synthesis of newly protein bands. The higher doses of sodium chloride produced a large number of polypeptides bands. The concentrations of sodium chloride from 200 to 300 mM were accompanied by the synthesis of polypeptide bands with high molecular weight.