Bennett G M, Seaver A, Calcott P H
Appl Environ Microbiol. 1981 Nov;42(5):843-9. doi: 10.1128/aem.42.5.843-849.1981.
A family of mutants of Salmonella typhimurium with altered lipopolysaccharide (LPS) core chain lengths were assessed for sensitivity to freeze-thaw and other stresses. Deep rough strains with decreased chain length in the LPS core were more susceptible to novobiocin, polymyxin B, bacitracin, and sodium lauryl sulfate during growth, to ethylenediaminetetraacetic acid and sodium lauryl sulfate in resting suspension, and to slow and rapid freeze-thaw in water and saline, and these strains exhibited more outer membrane damage than the wild type or less rough strains. Variations in the LPS chain length did not dramatically affect the sensitivity of the strains to tetracycline, neomycin, or NaCl in growth conditions or the degree of freeze-thaw-induced cytoplasmic membrane damage. The deeper rough isogenic strains incorporated larger quantities of less-stable LPS and less protein into the outer membrane than did the wild type or less rough mutants, indicating that the mutations affected outer membrane synthesis or organization or both. Nikaido's model of the role of LPS and protein in determining the resistance of gram-negative bacteria to low-molecular-weight hydrophobic antibiotics is discussed in relation to the stress of freeze-thaw.
对鼠伤寒沙门氏菌的一个脂多糖（LPS）核心链长度改变的突变体家族进行了冻融敏感性及其他应激敏感性评估。LPS核心链长度缩短的深粗糙菌株在生长过程中对新生霉素、多粘菌素B、杆菌肽和十二烷基硫酸钠更敏感，在静止悬浮液中对乙二胺四乙酸和十二烷基硫酸钠更敏感，在水和盐水中对缓慢和快速冻融更敏感，并且这些菌株比野生型或粗糙度较低的菌株表现出更多的外膜损伤。LPS链长度的变化对菌株在生长条件下对四环素、新霉素或氯化钠的敏感性，或冻融诱导的细胞质膜损伤程度没有显著影响。与野生型或粗糙度较低的突变体相比，更深粗糙的同基因菌株在外膜中掺入了大量稳定性较差的LPS和较少的蛋白质，这表明这些突变影响了外膜的合成或组织，或两者都有影响。结合冻融应激讨论了Nikaido关于LPS和蛋白质在决定革兰氏阴性菌对低分子量疏水抗生素抗性中作用的模型。
