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首页> 外文期刊>Journal of bacteriology >Ice nucleating activity of Pseudomonas syringae and Erwinia herbicola.
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Ice nucleating activity of Pseudomonas syringae and Erwinia herbicola.

机译：丁香假单胞菌和草欧文氏菌的冰成核活性。

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Chemical and biological properties of the ice nucleating sites of Pseudomonas syringae, strain C-9, and Erwinia herbicola have been characterized. The ice nucleating activity (INA) for both bacteria was unchanged in buffers ranging from pH 5.0 to 9.2, suggesting that there were no essential groups for which a change in charge in this range was critical. The INA of both bacteria was also unaffected by the addition of metal chelating compounds. Borate compounds and certain lectins markedly inhibited the INA of both types of bacterial cells. Butyl borate was not an inhibitor, but borate, phenyl borate, and m-nitrophenyl borate were, in order, increasingly potent inhibitors. These compounds have a similar order of affinity for cis hydroxyls, particularly for those found on sugars. Lentil lectin and fava bean lectin, which have binding sites for mannose or glucose, inhibited the INA of both bacteria. All other lectins examined had no effect. The inhibition of INA by these two types of reagents indicate that sugar-like groups are at or near the ice nucleating site. Sulfhydryl reagents were potent inhibitors of the INA of both bacteria. When treated with N-ethylmaleimide, p-hydroxymercuribenzoate, or iodoacetamide, the INA was irreversibly inhibited by 99%. The kinetics of inactivation with N-ethylmaleimide suggested that E. herbicola cells have at least two separate ice nucleating sites, whereas P. syringae cells have possibly four or more separate sites. The effect of infection with a virulent phage (Erh 1) on the INA of E. herbicola was examined. After multiple infection of a bacterial culture the INA was unchanged until 40 to 45 min, which was midway through the 95-min latent period. At that time, the INA activity began falling and 99% of the INA was lost by 55 min after infection, well before any cells had lysed. This decrease in INA before lysis is attributed to phage-induced changes in the cell wall.
机译：已经表征了丁香假单胞菌，菌株C-9和草欧文氏菌的冰成核位点的化学和生物学特性。在pH 5.0至9.2的缓冲液中，这两种细菌的​​冰成核活性（INA）均保持不变，这表明在此范围内没有至关重要的电荷变化基团。两种细菌的​​INA也不受金属螯合化合物的影响。硼酸盐化合物和某些凝集素显着抑制两种细菌细胞的INA。硼酸丁酯不是抑制剂，但是硼酸根，苯基硼酸根和间硝基苯基硼酸根依序是越来越有效的抑制剂。这些化合物对顺式羟基，特别是对糖上的顺式羟基具有相似的亲和力。扁豆凝集素和蚕豆凝集素具有甘露糖或葡萄糖的结合位点，可抑制两种细菌的​​INA。检查的所有其他凝集素均无作用。这两种类型的试剂对INA的抑制作用表明糖样基团位于冰成核位点或附近。巯基试剂是两种细菌INA的有效抑制剂。当用N-乙基马来酰亚胺，对羟基巯基苯甲酸酯或碘乙酰胺处理时，INA被不可逆地抑制了99％。用N-乙基马来酰亚胺灭活的动力学表明，草假单胞菌细胞具有至少两个分开的冰成核位点，而丁香假单胞菌细胞可能具有四个或更多个分开的位点。检查了用强力噬菌体（Erh 1）感染草herb肠球菌的INA的效果。在细菌培养物多次感染后，INA一直保持不变，直到40到45分钟，这是在95分钟潜伏期的中间。那时，INA活性开始下降，感染后55分钟，即所有细胞都未溶解之前，INA的99％丧失了。裂解前INA的减少归因于噬菌体诱导的细胞壁变化。

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