Ca2+,Mn2+等8种金属离子对软腐欧文氏菌一些致病因子的影响

 在离体试验中,不同金属离子对马铃薯软腐欧文氏菌(Erwinia carotovora subsp.carotovora)菌株StEcc-12生长,产生胞外酶和胞外酶活性具有不同的影响。在含果胶酸钠的培养液中,Ca²⁺促进生长,并使培养液中的果胶裂解酶(PL)、果胶水解酶(PG)和蛋白酶3种胞外酶分别提高1.4~23.4倍,0.3~2.9倍和0.7~6.5倍。Mn²⁺对StEcc-12生长及产生3种胞外酶的影响与Ca²⁺相似。Ni²⁺显著抑制细菌的生长,但在含Ni²⁺培养液中3种胞外酶的单位活性比对照高1.7倍以上。在酶粗提液中分别加入上述3种离子对PL酶的活性均有抑制作用。Zn²⁺对细菌生长没有显著影响,高浓度Al³⁺抑制细菌生长,这2种离子均能促进3种胞外酶的产生。随着Fe²⁺和K⁺浓度的增高,细菌生长减少,两种果胶酶产量降低,蛋白酶产量增加,粗提液中PL酶活性下降。Mg²⁺对细菌生长和胞外PG产生没有明显影响,提高Mg²⁺浓度有利于PL的产生。酶粗提液中加入Mg²⁺后PL活性增高。所有以上离子都能使聚半乳糖醛酸发生不同程度的凝聚,但只有Ca²⁺和Mg²⁺的有效凝聚浓度与薯块的实际浓度接近。

EFFECT OF 8 METAL IONS ON PATHOGENIC FACTORS OF SOFT ROT ERWINIA

Different metal ions had various effect on in vitro growth production of extracellular enzymes and enzyme activities of strain StEcc-12 of potato soft rot ( Erwinia carotovora subsp. carotovora ). In liquid media containing polygalacturonate, Ca2 increased growth of StEcc-12 and raised its production of extracellular pectic lyase (PL), polygalacturonase (PG) and protease up to 1. 4~23. 5, 0. 3~2. 9 and 0. 7~6. 5 times, respectively. Mn2 had the same effect as Ca2 on bacterial growth and production of 3 extracellular enzymes. Ni2 inhibited significantly the growth of pathogen, but the unit activities of 3 extracellular enzymes in suspension containing Ni2 is 1. 7 times higher than check. Addition of above 3 ions alone into a crude extraction inhibited PL activities. Zn2 han no effect on bacterial growth, and higher content of A13 inhibited, but these 2 ions increased production of extracellular enzymes. As Fe2 and K increased, bacterial growth and PL activities in extract solution decreased, synthesis of PL and PG reduced, but protease production raised. Mg2 had no significant effect on in vitro growth and extracellular PG. Increased Mg2 promoted PL synthesis and its activities. All 8 ions could agglutate poly-galacturonic sodium, but only Ca2 and Mg2 effectively binding it at a content similar to those in potato tubers (102. 2ppm and 179. 2ppm, respectively).