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ISME J. 2015 Jan;9(1):195-206. doi: 10.1038/ismej.2014.102. Epub 2014 Jul 22.

Bacterial metabolism of methylated amines and identification of novel methylotrophs in Movile Cave.

Author information

1
School of Environmental Sciences, University of East Anglia, Norwich, UK.
2
School of Life Sciences, University of Warwick, Coventry, UK.
3
Department of Biospeleology and Karst Edaphobiology, Emil Racoviţă Institute of Speleology, Bucharest, Romania.

Abstract

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) using (13)C-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 methylotroph Methylotenera mobilis is one of the dominant MMA utilisers in the cave. DNA-SIP experiments also showed that a new facultative methylotroph isolated in this study, Catellibacterium sp. 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 and N-methylglutamate is widespread among both methylotrophic and non-methylotrophic MMA utilisers from the cave.

PMID:
25050523
PMCID:
PMC4274414
DOI:
10.1038/ismej.2014.102
[Indexed for MEDLINE]
Free PMC Article

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