沙门菌CWDMs细胞结构的研究

Study on structure of the cell wall-deficient of S. typhi and S.paratyphi A

目的了解沙门菌CWDMs的形态、细胞超微结构以及细胞壁和胞浆膜的化学结构 ,探讨沙门菌CWDMs变异的性质及其机制。方法采用电子显微镜观察及抗生素、溶菌酶、毛地黄皂苷敏感试验等方法。结果伤寒杆菌和甲型副伤寒杆菌的CWDMs均为产生红色色素、直径 0 6～ 1 2 μm的革兰氏阴性圆球形态 ,单个或 2～ 4个细胞共存于一个不规则的壁样结构内 ,但未见其它结构如细胞核或其它细胞器。CWDMs对β—内酰胺类抗生素、多粘菌素B、溶菌酶的敏感性显著高于其亲代细菌型及其返祖菌 ,对毛地黄皂苷敏感 ;胆固醇的含量与白色念珠菌的相似。CWDMs的返祖菌即恢复了与其亲代细菌型一致的各种特性 ,同时也丧失了色素、类固醇代谢活性 ,且胞浆膜不含胆固醇。结论沙门菌染色体上可能天然存在红色色素及胆固醇代谢的基因 ,细胞壁缺陷导致沙门菌肽聚糖、外膜及其相关表面结构合成代谢的相关基因功能障碍 ,而使红色色素和胆固醇代谢基因活化。

Objects [WT5”BZ]To understand the morphology, finestructure, chemical properties of cell wall and cytoplasme membrane of the cell wall deficient mutants (CWDMs) of S. typhi and S. paratyphi A and to probe the properties and mechanisms of muntation of the CWDMs. [WT5”HZ]Methods [WT5”BZ]To use the electron microscopy and the sensitivity tests to antibiotics, lysozyme and digitonin etc. [WT5”HZ]Results [WT5”BZ]The CWDMs were Gram negative cocci with red pigment and 0.6～1.2μm in diameter and single or 2～4 cells were held toghther by a wall like structure but others structure, such as the nucleus and other cellular orgnelles, could not be found in the cells. The CWDMs were higher sensitivities to the β lactam antibiotics, polymyxin and lysozyme than their parental bacteria and the reverts which reverted from the CWDMs re expressed the properties as the parental bacteria. The CWDMs were sensitive to the digitonin but their parental bacteria and the reverts were not. The quantity of cholesterol in the CWDMs were similar to that of the C. albicans but the reverts lost the metabolic activations of the pigment and the steriol and the choleserol did not be found. [WT5”HZ]Conclusion [WT5”BZ]The genes of the red pigment and the metabolism of choleserol would be native in the S. typhi and S. paratyphi A.Deficient of the cell wall would active the genes of metabolism of the red pigment and choleserol but inhibit the genes of the peptidoglycan, outer membrane and other outer structure. [WT5”HZ]