嗜热菌的耐热L—乳酸脱氢酶的研究

About 200 strains of extreme thermophilic bacteria were isolated from hot springs in Guandong province. A strain, HG25, was found to produce thermostable intracellular L-lactate dehydrogenase (EC. 1.1.1.27). It has the characteristic of Thermus sp. The cells were gram-negative, non-sporulating, nonmotile, aerobic rods containing yellow pigment. The optimum temperature for growth was between 65 degrees C to 75 degrees C, the maximum 85 degrees C, and minimum 40 degrees C. The generation time at the optimum was about 80 min. Starch was not hydrolyzed. Acid was not produced from glucose. The G+C content in DNA was 62-65 mol% (Tm). As the properties of strain HG25 is similar to those of Thermus aquaticus and T. thermophilus HB 8 belonging to the genus Thermus. The thermostable L-lactate dehydrogenase was partially purified by ammonium sulfate fractionation and DEAE-cellulose column chromatography. For pyruvate reduction, the optimum temperature of the enzyme was 60 degrees C and pH 8.0. After incubation in 0.1 mol/L phosphate buffer pH 7.4 at 70 degrees C for 10 min, the enzyme retained about 85% of its original activity. The half-live time (t1/2) at 85 degrees C was 10 min.     

对肿瘤有抑制作用的假单胞菌新种——济南假单胞菌

1973年自山东省无影山表土中分离出一株革兰氏阴性杆菌(编号161)。它对小鼠的宫颈癌、肝癌和黑色素瘤有明显抑制作用;对金黄色葡萄球菌、枯草芽孢杆菌和微球菌也有拮抗作用。