Integrated methodological approach reveals microbial diversity and functions in aerobic groundwater microcosms adapted to vinyl chloride
Integrated methodological approach reveals microbial diversity and functions in aerobic groundwater microcosms adapted to vinyl chloride
复制标题
DOI：
10.1093/femsec/fiy124
复制
发表时间：
2018-06
影响因子：
4.2
通讯作者：
Xikun Liu;Yang Wu;F. P. Wilson;Ke Yu;C. Lintner;A. Cupples;T. Mattes
中科院分区：
文献类型：
--
作者：
Xikun Liu;Yang Wu;F. P. Wilson;Ke Yu;C. Lintner;A. Cupples;T. Mattes
氯乙烯（VC）是一种已知的人类致癌物，通常由地下水（GW）中氯化乙烯的不完全还原脱氯形成。一个综合的微生物生态学方法，包括细菌富集和分离，碳稳定同位素探测（SIP）和宏基因组和基因组测序应用于乙烯喂养的GW微观世界，迅速过渡到有氧生长VC。放线菌，变形菌和拟杆菌占主导地位的微生物群落在乙烯和VC生长的文化。用13C2-VC进行SIP证明了类诺卡氏菌属（Nocardioides spp.）显著参与VC的碳吸收（52.1%-75.7%富集于重质组分）。沉降杆菌属、土壤杆菌属和假单胞菌属。还将VC中的13 C掺入基因组DNA中。分离出了同化乙烯和VC的类诺卡氏菌菌株XL1。测序显示一个大的（约300 kbp）质粒携带编码烯烃单加氧酶和环氧烷烃：辅酶M转移酶，酶参与有氧VC和乙烯生物降解的基因。该质粒与VC同化类诺卡氏菌属菌株JS 614中发现的pNOCA 01 100%相同。富集培养物的宏基因组分析表明，与VC碳吸收有关的其他细菌具有通过环氧化物水解酶或谷胱甘肽S-转移酶（假单胞菌）对环氧化物解毒和/或代谢VC环氧化物分解产物和下游VC代谢物的遗传潜力。这项研究提供了新的功能性的见解有氧VC代谢内的GW微生物群落。
Vinyl chloride (VC), a known human carcinogen, is often formed in groundwater (GW) by incomplete reductive dechlorination of chlorinated ethenes. An integrated microbial ecology approach involving bacterial enrichments and isolations, carbon stable-isotope probing (SIP) and metagenome and genome sequencing was applied to ethene-fed GW microcosms that rapidly transitioned to aerobic growth on VC. Actinobacteria, Proteobacteria and Bacteroidetes dominated the microbial communities in ethene- and VC-grown cultures. SIP with 13C2-VC demonstrated that Nocardioides spp. significantly participated in carbon uptake from VC (52.1%-75.7% enriched in heavy fractions). Sediminibacterium, Pedobacter and Pseudomonas spp. also incorporated 13C from VC into genomic DNA. Ethene- and VC-assimilating Nocardioides sp. strain XL1 was isolated. Sequencing revealed a large (∼300 kbp) plasmid harboring genes encoding alkene monooxygenase and epoxyalkane: coenzyme M transferase, enzymes known to participate in aerobic VC and ethene biodegradation. The plasmid was 100% identical to pNOCA01 found in VC-assimilating Nocardioides sp. strain JS614. Metagenomic analysis of enrichment cultures indicated other bacteria implicated in carbon uptake from VC possessed the genetic potential to detoxify epoxides via epoxide hydrolase or glutathione S-transferase (Pseudomonas) and/or metabolize VC epoxide breakdown products and downstream VC metabolites. This study provides new functional insights into aerobic VC metabolism within a GW microbial community.