Flagellar motility contributes to the invasion and survival of Aeromonas hydrophila in Anguilla japonica macrophages
Flagellar motility contributes to the invasion and survival of Aeromonas hydrophila in Anguilla japonica macrophages
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DOI：
10.1016/j.fsi.2014.05.016
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发表时间：
2014-08-01
影响因子：
4.7
通讯作者：
Yan, Qingpi
中科院分区：
文献类型：
--
作者：
Qin, Yingxue;Lin, Guifang;Yan, Qingpi
致病菌与宿主吞噬细胞的相互作用是复杂的。一般认为，只有专性细胞内病原体才能侵入并在宿主吞噬细胞中存活。在本研究中，我们发现致病性嗜水气单胞菌B11也能在体外侵入其宿主日本鳗鲡的巨噬细胞并存活。为了进一步研究嗜水单胞杆菌在宿主巨噬细胞中的侵袭和存活机制，利用mini-Tn10转座子诱变系统，将供体大肠杆菌Sm10 （pLOFKm）与受体嗜水单胞杆菌B11细胞偶联，生成插入突变文库。在465个个体菌落中，有13个突变体在巨噬细胞内存活受损，其中突变体BM116是受损最严重的菌株。分子分析表明，mini-Tn10插入了突变体BM116约1335 bp的ORF （GenBank登录号JQ974982）。该ORF编码了一个由445个氨基酸组成的蛋白，该蛋白与嗜水拟南蝽的鞭毛钩蛋白FlgE具有最高的同源性（99.6%）。ATCC 7966。研究了野生型B11、突变体B116和补体菌株的生物学特性。结果表明，突变体BM116的鞭毛缺失，与野生型和补充菌株相比，这些突变体细菌在宿主巨噬细胞中的运动性、粘附性、入侵和存活能力都存在缺陷。这些发现表明，flgE是嗜水单胞虫鞭毛形成所必需的，而鞭毛运动是嗜水单胞虫在宿主巨噬细胞中侵袭和存活所必需的。我们的发现为了解非细胞内致病菌在宿主吞噬细胞中的侵袭和生存以及致病菌与宿主的相互作用提供了重要的新认识。(C) 2014 Elsevier Ltd.版权所有。
The interaction between pathogenic bacteria and the host phagocytes is complicated. It is generally believed that only obligate intracellular pathogens can invade and survive in host phagocytes. In this study, we revealed that the pathogenic Aeromonas hydrophila B11 can also invade and survive in the macrophages of its host Anguilla japonica in vitro. To further investigate the mechanisms of A. hydrophila invasion and survival in host macrophages, a mini-Tn10 transposon mutagenesis system was used to generate an insertion mutant library by cell conjugation between the donor Escherichia coli Sm10 (pLOFKm) and the recipient A. hydrophila B11. Out of 465 individual colonies, 13 mutants impaired in survival within macrophages were selected, and the mutant BM116 was the most seriously impaired strain. Molecular analysis showed that an ORF of approximately 1335 bp (GenBank accession numbers JQ974982) of the mutant BM116 was inserted by mini-Tn10. This ORF putatively encodes a deduced 445 amino acids protein that displays the highest identity (99.6%) with the flagellar hook protein FlgE of A. hydrophila subsp. hydrophila ATCC 7966. The biological characteristics of the wild-type B11, the mutant B116 and the complemented strain were investigated. The results reveal that the flagella of the mutant BM116 was absent and that these mutant bacteria exhibited defective motility, adhesion, and invasion and survival in host macrophages when compared with the wild type and the complemented strain. These findings indicate that flgE is required for flagellum biogenesis in A. hydrophila and that flagellar motility is required for A. hydrophila invasion and survival in the macrophages of its host. Our findings provide an important new understanding of the nonintracellular pathogenic bacteria invasion and survival in host phagocytes and the interactions between the pathogens and their host. (C) 2014 Elsevier Ltd. All rights reserved.