软腐欧氏杆菌在离体条件下产生胞外酶的比较研究

 3种软腐细菌在21,26和31℃下及6种培养液中的生长量和产生胞外酶的能力各不相同。Ecc在26℃生长最好,Eca为21℃,Ech在三种温度下的生长量差别不大。与其它2种细菌比较,Ech的生长及产生果胶裂解酶(PL)的能力总是最强的。随着温度的升高,各种细菌的PL活性都下降。果胶水解酶(PG)变化不大,但Ech在高温下产PG有减少趋势,且总没有另二种细菌的活性强。Eca以26℃时产PG最适宜。Ech在较高温度下蛋白酶活性大大下降,而Ecc,变化不大,Eca的蛋白酶活性则随温度升高而加强。培养液的无细胞滤液对马铃薯块茎组织的浸离力与其中PL的活性有密切关系,但没有或只有很低果胶酶活性,而蛋白酶活性正常的这种滤液也能使小薯碟浸离。Eca在31℃培养后果胶酶活性很低,蛋白酶活性很高,其无细胞滤液对马铃薯组织也表现较强浸离力。

COMPARISON ON EXTRACELLULAR ENZYMES OF SOFT ROT ERWINIAS IN VITRO

Three soft rot erwinias were different in growth and the production of extracellular enzymes at 21, 26 and 31℃ and in 6 liquid media. Ecc grows most rapidly at 26℃, Eca at 21℃, while growth of Ech was similar in 3 temperatures. Comparatively, the growth and pectinlyase (PL) activity of Ech are the highest and its polygalacturonase (PG) activity the lowest among 3 bacteria. AS temperature increased, PL activity of 3 bacteria decreased, protease of Ech sharply reduced, but protease of Eca significantly increased. There is a significant relation between PL activity in cell-free filtrates of culture and their maceration to potato tuber tissues. However, in filtrate There is no or little pectinase activity, but protease activity is regular and also macerates tuber tissues.