Schlecht S, Fromme I
Zentralbl Bakteriol Orig A. 1975 Oct;233(2):199-222.
Chemical and serological investigations were carried out on lipopolysaccharides of 4 Salmonella S-forms and of 1 SR-mutant, extracted from bacteria at different ages of culture (early exponential to stationary growth phase). The results show that the fatty acid composition of Lipid A (lauric-, myristic-, palmitic-, and beta-hydroxy-myristic acids) does not undergo any significant change during the growth of the cultures. However, there are differences in the molar ratios of the fatty acids from strain to strain. In all phases of growth Lipid A is substituted by basaloligosaccharide, to the same extent, as can be seen from the constant ratios of beta-hydroxy-myristic acid: heptose. Serological experiments (haemagglutination inhibition tests, absorption of antibodies by LPS-coated erythrocytes) showed that in no case the basaloligosaccharide is completely substituted by O-specific chains and that basaloligosaccharide exhibits free R-antigen structures which are mainly of chemotypes Ra, Rb and Rc, for the SR-mutant only of types Ra and Rb. There is no demonstrable dependence upon the phases of growth. In the O-specific polysaccharide chains the sugars of the main chain and the side bound dideoxy sugars (abequose and tyvelose) show a constant 1:1 molar ratio in all phases. In the case of S. typhimurium, antigen factors 1, 4 and 12(2), the biosynthesis of which is controlled by modifying oaf genes and/or by a lysogenic phage, are of a somewhat weaker expression in the exponential phase than in the latter phases of growth. In the SR-mutant, lipopolysaccarides with (low) serological O1 and O12(2) activity are only extractable by the phenol/water method, but not by the PCP method. In three out of four S-forms, changes occur in the length of the O-specific polysaccharide chains, whereas the number of repeating units of the fourth strain remains almost unchanged. The lipopolysaccharides of the SR-mutant contain in all phases of growth about one repeating unit. In all strains the covering of the cell surface by lipopolysaccharide molecules changes during the course of growth, as can be seen by comparing the relative cell surface and the content of Lipid A fatty acids of the bacteria. Lipid A synthesis in the 4 S-forms is reduced in the exponential phase and/or in the phase of delayed growth acceleration. The extent of biosynthesis of the carbohydrate moiety of lipopolysaccharides is independent of that of Lipoid A. In the SR-mutant, Lipoid A and Polysaccharide are formed in increased amounts in the exponential growth phase.
对4种沙门氏菌S型菌株和1种SR突变体的脂多糖进行了化学和血清学研究，这些脂多糖是从不同培养年龄（从指数生长早期到稳定生长期）的细菌中提取的。结果表明，脂质A的脂肪酸组成（月桂酸、肉豆蔻酸、棕榈酸和β-羟基肉豆蔻酸）在培养物生长过程中没有发生任何显著变化。然而，不同菌株的脂肪酸摩尔比存在差异。在生长的各个阶段，脂质A都被基础寡糖以相同程度取代，这从β-羟基肉豆蔻酸与庚糖的恒定比例可以看出。血清学实验（血凝抑制试验、用LPS包被的红细胞吸收抗体）表明，基础寡糖在任何情况下都不会被O特异性链完全取代，并且基础寡糖呈现出游离的R抗原结构，主要是Ra、Rb和Rc化学型，SR突变体仅为Ra和Rb型。这与生长阶段没有明显的相关性。在O特异性多糖链中，主链糖和侧链结合的双脱氧糖（阿比可糖和泰威糖）在所有阶段都呈现恒定的1:1摩尔比。对于鼠伤寒沙门氏菌，其抗原因子1、4和12(2)的生物合成受oaf基因修饰和/或溶原性噬菌体控制，在指数生长期的表达比生长后期略弱。在SR突变体中，具有（低）血清学O1和O12(2)活性的脂多糖只能通过苯酚/水法提取，而不能通过PCP法提取。在4种S型菌株中的3种中，O特异性多糖链的长度发生了变化，而第4种菌株的重复单元数量几乎保持不变。SR突变体的脂多糖在生长的各个阶段都含有约一个重复单元。通过比较细菌的相对细胞表面和脂质A脂肪酸含量可以看出，在所有菌株中，脂多糖分子对细胞表面的覆盖在生长过程中都会发生变化。在指数生长期和/或生长加速延迟期，4种S型菌株中的脂质A合成减少。脂多糖碳水化合物部分的生物合成程度与脂质A的生物合成程度无关。在SR突变体中，脂质A和多糖在指数生长期的合成量增加。
