Purification and characterization of enterotoxin produced by Aeromonas sobria
Purification and characterization of enterotoxin produced by Aeromonas sobria
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DOI：
10.1111/j.1348-0421.1998.tb02343.x
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发表时间：
1998-01-01
影响因子：
2.6
通讯作者：
Okamoto, K
中科院分区：
文献类型：
--
作者：
Fujii, Y;Nomura, T;Okamoto, K
我们提纯了温和气单胞菌毒素，该毒素能在小鼠肠环试验中产生阳性反应。纯化的毒素不仅在环状试验中呈阳性反应，而且在溶血试验中也呈阳性反应。随后，我们克隆了该毒素基因，并证明该基因产物具有溶血和肠毒素活性。这些结果表明，温和气单胞菌肠毒素具有溶血活性。毒素基因的核苷酸序列测定和氨基酸序列分析表明，该毒素是由488个氨基酸残基组成的前体，其24个氨基端氨基酸残基在成熟毒素中被去除，因为纯化毒素的抗血清不仅中和了温和弧菌和嗜水气单胞菌活细胞诱导的液体积聚，而且与抗原性相关的毒素S在这些生物引起腹泻的过程中起着重要作用。在毒素损伤的中国仓鼠卵巢(CHO)细胞中，加入葡聚糖抑制了细胞内乳酸脱氢酶(LDH)的释放，抑制了细胞LDH的释放，抑制了毒素对红细胞的溶解作用，表明毒素在细胞膜上形成了孔洞，细胞受到了由孔道形成的渗透梯度的损伤。然而，对暴露于该毒素的肠道细胞进行的组织病理学检查显示，该毒素可在小鼠肠环内引起液体积聚，而不会对细胞造成损害。
We purified the toxin of Aeromonas sobria capable of inducing a positive response in the mouse intestinal loop assay. The purified toxin showed a positive response not only in the loop assay but also in a hemolytic assay. Subsequently, we cloned the toxin gene and demonstrated that the product of this gene possessed both hemolytic and enterotoxic activities. These results showed that the enterotoxin of A. sobria possesses hemolytic activity. Nucleotide sequence determination of the toxin gene and amino acid sequence analysis of the purified toxin revealed that it is synthesized as a precursor composed of 488 amino acid residues, and that the 24 amino-terminal amino acid residues of the precursor is removed in the mature toxin, As antiserum against the purified toxin neutralized the fluid accumulation induced by living cells not only of A. sobria but also of A. hydrophila, this and antigenically related toxin(s) are thought to play an essential role in the induction of diarrhea by these organisms. The toxin-injured Chinese hamster ovary (CHO) cells induced the release of intracellular lactose dehydrogenase (LDH), The release of LDH from CHO cells and the lysis of erythrocytes by the toxin were repressed by the addition of dextran to the reaction solution, indicating that the toxin forms pores in the membranes and that the cells were injured by the osmotic gradient developed due to pore formation. However, the histopathological examination of intestinal cells exposed to the toxin showed that it caused fluid accumulation in the mouse intestinal loop without causing cellular damage.