Müller Christine, Birmes Franziska S, Niewerth Heiko, Fetzner Susanne
Institute of Molecular Microbiology and Biotechnology, University of Münster, Münster, Germany.
Institute of Molecular Microbiology and Biotechnology, University of Münster, Münster, Germany
Appl Environ Microbiol. 2014 Dec;80(23):7266-74. doi: 10.1128/AEM.02342-14. Epub 2014 Sep 19.
A bacterial strain, which based on the sequences of its 16S rRNA, gyrB, catA, and qsdA genes, was identified as a Rhodococcus sp. closely related to Rhodococcus erythropolis, was isolated from soil by enrichment on the Pseudomonas quinolone signal [PQS; 2-heptyl-3-hydroxy-4(1H)-quinolone], a quorum sensing signal employed by the opportunistic pathogen Pseudomonas aeruginosa. The isolate, termed Rhodococcus sp. strain BG43, cometabolically degraded PQS and its biosynthetic precursor 2-heptyl-4(1H)-quinolone (HHQ) to anthranilic acid. HHQ degradation was accompanied by transient formation of PQS, and HHQ hydroxylation by cell extracts required NADH, indicating that strain BG43 has a HHQ monooxygenase isofunctional to the biosynthetic enzyme PqsH of P. aeruginosa. The enzymes catalyzing HHQ hydroxylation and PQS degradation were inducible by PQS, suggesting a specific pathway. Remarkably, Rhodococcus sp. BG43 is also capable of transforming 2-heptyl-4-hydroxyquinoline-N-oxide to PQS. It thus converts an antibacterial secondary metabolite of P. aeruginosa to a quorum sensing signal molecule.
一株细菌，基于其16S rRNA、gyrB、catA和qsdA基因序列，被鉴定为与红平红球菌密切相关的红球菌属菌株，该菌株是通过在铜绿假单胞菌喹诺酮信号[PQS；2-庚基-3-羟基-4(1H)-喹诺酮]上进行富集从土壤中分离得到的，PQS是机会致病菌铜绿假单胞菌所采用的群体感应信号。该分离株被命名为红球菌属菌株BG43，它能共代谢降解PQS及其生物合成前体2-庚基-4(1H)-喹诺酮(HHQ)生成邻氨基苯甲酸。HHQ的降解伴随着PQS的短暂形成，细胞提取物对HHQ的羟基化作用需要NADH，这表明菌株BG43具有一种与铜绿假单胞菌的生物合成酶PqsH同功能的HHQ单加氧酶。催化HHQ羟基化和PQS降解的酶可被PQS诱导，提示存在一条特定途径。值得注意的是，红球菌属BG43菌株还能够将2-庚基-4-羟基喹啉-N-氧化物转化为PQS。因此，它将铜绿假单胞菌的一种抗菌次级代谢产物转化为一种群体感应信号分子。
