Mercury resistance transposons in Bacilli strains from different geographical regions
Mercury resistance transposons in Bacilli strains from different geographical regions
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不同地理区域的杆菌菌株中的汞抗性转座子
DOI：
10.1093/femsle/fnw013
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发表时间：
2016
影响因子：
2.1
通讯作者：
Ginro Endo
中科院分区：
文献类型：
--
作者：
Kazuaki Matsui;Satoshi Yoshinami;Masaru Narita;Mei-Fang Chien;Le T. Phung;Simon Silver;Ginro Endo
从世界各地的自然环境中分离出了总共65种孢子形成的耐汞细菌，以了解通过水平基因运动在相关芽孢杆菌属中获得额外的基因和耐汞转座子的传播。PCR扩增使用一个单一的引物互补TnMERI 1-like转座子的反向重复序列显示，65株中有12个转座子样结构。扩增出4种类型的片段：Tn 5084、Tn 5085、TndMER 3（一种新发现的缺失型转座子样片段）和Tn 6294（一种新发现的转座子）。TndMER 3是一个3.5kb的序列，携带amerRETPA操纵子和nomerBor转座酶基因。与俄罗斯地衣芽孢杆菌菌株FA 6 -12的操纵子有关。DNA同源性分析表明，Tn 6294是一个8.5kb的序列，它可能是通过整合TnMERI 1型转座酶和解离酶基因以及merR 2和merB 1基因从TndMER 3衍生而来的。虽然Tn 6294只含有merB 1序列，而不具有B. Tn 5084的merB 2和merB 3序列，但Tn 6294对有机汞化合物具有广谱的抗汞性。蜡状芽孢杆菌菌株RC 607。Tn 6294菌株编码的汞还原酶（MerA）长度小于600个氨基酸，N端有一个汞结合结构域，而MB 1和RC 607菌株编码的MerA具有两个串联结构域。因此，TndMER 3和Tn 6294是TnMERI 1样转座子的较短原型。芽孢杆菌Tn 6294的鉴定和Paenibacillussp.来自南极洲的研究表明TnMERI 1样转座子跨越细菌物种和地理障碍的广泛水平传播。
A total of 65 spore-forming mercury-resistant bacteria were isolated from natural environments worldwide in order to understand the acquisition of additional genes by and dissemination of mercury resistance transposons across related Bacilli genera by horizontal gene movement. PCR amplification using a single primer complementary to the inverted repeat sequence of TnMERI1-like transposons showed that 12 of 65 isolates had a transposon-like structure. There were four types of amplified fragments: Tn5084, Tn5085, TndMER3(a newly identified deleted transposon-like fragment) and Tn6294(a newly identified transposon). TndMER3is a 3.5-kb sequence that carries amerRETPAoperon with nomerBor transposase genes. It is related to themeroperon ofBacillus licheniformisstrain FA6-12 from Russia. DNA homology analysis shows that Tn6294is an 8.5-kb sequence that is possibly derived from TndMER3by integration of a TnMERI1-type transposase and resolvase genes and in addition themerR2andmerB1genes. Bacteria harboring Tn6294exhibited broad-spectrum mercury resistance to organomercurial compounds, although Tn6294had onlymerB1and did not have themerB2andmerB3sequences for organomercurial lyases found in Tn5084ofB. cereusstrain RC607. Strains with Tn6294encode mercuric reductase (MerA) of less than 600 amino acids in length with a single N-terminal mercury-binding domain, whereas MerA encoded by strains MB1 and RC607 has two tandem domains. Thus, TndMER3and Tn6294are shorter prototypes for TnMERI1-like transposons. Identification of Tn6294inBacillussp. from Taiwan and inPaenibacillussp. from Antarctica indicates the wide horizontal dissemination of TnMERI1-like transposons across bacterial species and geographical barriers.