Bacterial metabolism of methylated amines and identification of novel methylotrophs in Movile Cave
Bacterial metabolism of methylated amines and identification of novel methylotrophs in Movile Cave
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DOI：
10.1038/ismej.2014.102
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发表时间：
2014-07
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通讯作者：
D. Wischer;D. Kumaresan;D. Kumaresan;A. Johnston;Myriam El Khawand;Jason Stephenson;Alexandra Hillebrand-Voiculescu;Yin Chen;J. Murrell
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文献类型：
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作者：
D. Wischer;D. Kumaresan;D. Kumaresan;A. Johnston;Myriam El Khawand;Jason Stephenson;Alexandra Hillebrand-Voiculescu;Yin Chen;J. Murrell
罗马尼亚的莫维尔洞穴是一个不同寻常的地下生态系统，数百万年来一直与世隔绝，靠非光养碳固定维持。甲烷和硫氧化细菌是主要的初级生产者，支持一个复杂的食物网络，其中包括细菌、真菌和适应洞穴的无脊椎动物。Movile Cave中的一系列甲基营养细菌生长在一种碳化合物上，包括甲基化胺，这些化合物是通过分解富含有机物质的微生物垫产生的。采用培养研究和使用13C-单甲胺的DNA稳定同位素探针(DNA-SIP)相结合的方法，研究了甲基化胺作为移动洞穴细菌的碳源和氮源的作用。针对最近发现的间接MMA氧化途径的第一个酶--γ-谷氨酰甲酰胺合成酶(GMAs)基因，开发了两套新的引物，用于功能基因探测。Sip实验表明，专性甲基营养菌是洞穴中MMA的主要利用者之一。DNA-SIP实验还表明，本研究分离到一种新的兼性甲基硫杆菌--卡氏杆菌。LW-1可能是移动洞穴中最活跃的MMA使用器之一。在Movile Cave中，甲基化胺也被广泛的非甲基营养细菌用作氮源。基于PCR的细菌分离筛选表明，涉及GMA和N-甲基谷氨酸的间接MMA氧化途径在来自洞穴的甲基营养和非甲基营养的MMA利用者中普遍存在。
Movile Cave, Romania, is an unusual underground ecosystem that has been sealed off from the outside world for several million years and is sustained by non-phototrophic carbon fixation. Methane and sulfur-oxidising bacteria are the main primary producers, supporting a complex food web that includes bacteria, fungi and cave-adapted invertebrates. A range of methylotrophic bacteria in Movile Cave grow on one-carbon compounds including methylated amines, which are produced via decomposition of organic-rich microbial mats. The role of methylated amines as a carbon and nitrogen source for bacteria in Movile Cave was investigated using a combination of cultivation studies and DNA stable isotope probing (DNA-SIP) using13C-monomethylamine (MMA). Two newly developed primer sets targeting the gene for gamma-glutamylmethylamide synthetase (gmaS), the first enzyme of the recently-discovered indirect MMA-oxidation pathway, were applied in functional gene probing. SIP experiments revealed that the obligate methylotrophMethylotenera mobilisis one of the dominant MMA utilisers in the cave. DNA-SIP experiments also showed that a new facultative methylotroph isolated in this study,Catellibacteriumsp. LW-1 is probably one of the most active MMA utilisers in Movile Cave. Methylated amines were also used as a nitrogen source by a wide range of non-methylotrophic bacteria in Movile Cave. PCR-based screening of bacterial isolates suggested that the indirect MMA-oxidation pathway involving GMA andN-methylglutamate is widespread among both methylotrophic and non-methylotrophic MMA utilisers from the cave.