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首页> 外文期刊>Infection and immunity >Quantitative analysis and partial characterization of cytotoxin production by Salmonella strains.
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Quantitative analysis and partial characterization of cytotoxin production by Salmonella strains.

机译：沙门氏菌菌株产生的细胞毒素的定量分析和部分表征。

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The pathogenesis of the wide-spectrum human disease caused by Salmonella species is poorly understood. Cytotoxin production by other enteric pathogens has been increasingly investigated recently, and data are accumulating regarding the role of cytotoxins in enteric infections and hemolytic uremic syndrome. We studied the cytotoxic activity of 131 Salmonella strains of the major serotypes, including 94 strains of Salmonella enteritidis, 12 strains of Salmonella typhi, and 25 strains of Salmonella choleraesuis. Cytotoxicity was quantitatively determined in sonic extracts by a [3H]thymidine-labeled HeLa cell assay. All Salmonella strains examined showed some degree of cytotoxic activity. The geometric means +/- standard deviations of the amounts of cytotoxin produced (50% cytotoxic dose per milligram of bacterial protein) were 27 +/- 2 for S. typhi, 65 +/- 2 for S. enteritidis, and 117 +/- 2 for S. choleraesuis. Analysis of variance showed that the differences in cytotoxin production by the three species were significant (P less than 0.001). No significant differences were found between stool isolates and invasive strains of the same species. Neutralization studies showed that the cytotoxins produced by all Salmonella strains were immunologically distinct from Shiga toxin and the closely related Shiga-like toxins produced by Escherichia coli. DNA hybridization studies with DNA probes for Shiga-like toxins of types I and II showed no hybridization. In each species the cytotoxin was heat labile and sensitive to trypsin treatment, which indicated that its active component was probably protein in nature. Upon ultrafiltration with Amicon membranes and gel filtration chromatography, cytotoxic activity was found in the molecular weight range of 56,000 to 78,000. Our findings indicate that salmonellae produce cytotoxin(s) that may play a role in the manifestations of the various species.
机译：沙门氏菌引起的广谱人类疾病的发病机理知之甚少。最近，越来越多地研究了其他肠道病原体产生细胞毒素的情况，并且有关细胞毒素在肠道感染和溶血性尿毒症综合征中的作用的数据正在积累。我们研究了131种主要血清型沙门氏菌菌株的细胞毒活性，其中包括94株肠炎沙门氏菌，12株伤寒沙门氏菌和25株霍乱沙门氏菌。通过[3H]胸苷标记的HeLa细胞分析定量测定声音提取物中的细胞毒性。所有检查的沙门氏菌菌株均显示出一定程度的细胞毒活性。产生的细胞毒素量的几何平均值+/-标准偏差（每毫克细菌蛋白50％细胞毒性剂量）对于伤寒沙门氏菌是27 +/- 2，对于肠炎沙门氏菌是65 +/- 2，而117 + / -霍乱链球菌为2。方差分析表明，这三个物种在细胞毒素产生方面的差异是显着的（P小于0.001）。在粪便分离株和同一物种的入侵菌株之间未发现显着差异。中和研究表明，所有沙门氏菌菌株产生的细胞毒素在免疫学上都不同于志贺毒素和大肠杆菌产生的密切相关的志贺样毒素。用DNA探针对I型和II型志贺氏样毒素进行的DNA杂交研究表明没有杂交。在每个物种中，细胞毒素都是不耐热的并且对胰蛋白酶处理敏感，这表明其活性成分可能是自然界中的蛋白质。经Amicon膜超滤和凝胶过滤层析后，发现细胞毒活性的分子量范围为56,000至78,000。我们的发现表明沙门氏菌会产生可能在各种物种的表现中起作用的细胞毒素。

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