Environmental and Biochemical Studies on Changes of Phosphatase Activity of Microorganisms in Tideland Sediments.

点击翻译按钮获取中文摘要

Tidelands have multiple functions, e.g., flood control, waste purification, nutrient supplementation to plants or plankton and fishery production. These functions are supported by the microorganisms in tideland sediments. Extracellular enzymes, which are secreted by microorganisms or liberated through cell lysis, catalyze hydrolysis of organic materials to elemental nutrients.In previous studies, we showed that the addition of proteins to the sediments significantly enhances phosphatase activity. To obtain information on the mechanism of the biological link between the protein loading and the induction of phosphatase activity, it is essential to characterize the enzymatic degradation process of load protein in the tideland sediments. For this purpose, we developed a biochemical method with SDS-polyacrylamide gel electrophoresis (SDS-PAGE), which could separate protein fragments digested by proteases in the tideland sediments on a polyacrylamide gel. The protease activities and the hydrolytic products of the protein loaded to soils from the Kamo River were studied using the method. The results indicate that the soils from the middle reach and the estuarine water regions have high protease activities. However, the polypeptide patterns produced by sedimental proteases were different, suggesting that tideland sediments have specific proteases. We also reported an electrophoretic method to reveal proteases involved in tideland sediments based on a modified method reported by Heussen and Dowdle. Using the method, we clarified the presence of several proteases in tidelands. Moreover, it was revealed that the regions which show the high induction effect of phosphatase by protein loading, have characteristic proteases in their sediments.