Gänzle M G, Hertel C, Hammes W P
Universität Hohenheim, Institut für Lebensmitteltechnologie (ALT), Stuttgart, Germany.
Int J Food Microbiol. 1999 Apr 1;48(1):37-50. doi: 10.1016/s0168-1605(99)00026-4.
We have determined the effects of the following factors on the resistance of Gram-negative bacteria against nisin and curvacin A: (i) chemotype of the lipopolysaccharide (LPS), (ii) addition of agents permeabilizing the outer membrane, (iii) the fatty acid supply of the growth medium, and (iv) the adaptation to acid and salt stress. Bacteriocin activity was determined against growing and resting cells as well as protoplasts. All smooth strains of Escherichia coli and Salmonella enterica serovar Typhimurium were highly resistant towards the bacteriocins, whereas mutants that possess the core of the LPS, but not the O antigen, as well as deep rough LPS mutants were sensitive. Antibiotics with outer membrane permeabilizing activity, polymyxin B and polymyxin B nonapeptide, increased the sensitivity of smooth E. coli towards nisin, but not that of deep rough mutants. Incorporation of 1 g l(-1) of either oleic acid or linoleic acid to the growth media greatly increased the susceptibility of E. coli LTH1600 and LTH4346 towards bacteriocins. Both strains of E. coli were sensitive to nisin and curvacin A at a pH of less than 5.5 and more than 3% (w/v) NaCl. Adaptation to sublethal pH or higher NaCl concentrations (pH 4.54 and 5.35 or 4.5% (w/v) NaCl) provided only limited protection against the bacteriocidal activity of nisin and curvacin A. Adaptation to 4.5% (w/v) NaCl did not result in cross protection to bacteriocin activity at pH 4.4, but rendered the cells more sensitive towards bacteriocins.
我们已经确定了以下因素对革兰氏阴性菌对乳链菌肽和弯曲菌素A抗性的影响：（i）脂多糖（LPS）的化学型，（ii）添加可通透外膜的试剂，（iii）生长培养基中的脂肪酸供应，以及（iv）对酸和盐胁迫的适应性。针对生长和静止细胞以及原生质体测定了细菌素活性。所有光滑型大肠杆菌和鼠伤寒沙门氏菌血清型鼠伤寒菌株对细菌素具有高度抗性，而具有LPS核心但没有O抗原的突变体以及深粗糙LPS突变体则敏感。具有外膜通透活性的抗生素多粘菌素B和多粘菌素B九肽增加了光滑型大肠杆菌对乳链菌肽的敏感性，但对深粗糙突变体则没有。向生长培养基中添加1 g l(-1)的油酸或亚油酸大大增加了大肠杆菌LTH1600和LTH4346对细菌素的敏感性。在pH值小于5.5和NaCl浓度高于3%（w/v）时，两种大肠杆菌菌株对乳链菌肽和弯曲菌素A均敏感。适应亚致死pH值或更高的NaCl浓度（pH 4.54和5.35或4.5%（w/v）NaCl）对乳链菌肽和弯曲菌素A的杀菌活性仅提供有限的保护。适应4.5%（w/v）NaCl不会导致对pH 4.4时细菌素活性的交叉保护，但会使细胞对细菌素更敏感。
