Phylogenetic Structure and Metabolic Properties of Microbial Communities in Arsenic-Rich Waters of Geothermal Origin
Articolo
Data di Pubblicazione:
2017
Citazione:
Phylogenetic Structure and Metabolic Properties of Microbial Communities in Arsenic-Rich Waters of Geothermal Origin / S. Zecchin, A. S., F. S., C. B., A. Corsini, L. Cavalca, R. S.. - In: FRONTIERS IN MICROBIOLOGY. - ISSN 1664-302X. - 8(2017 Dec 12).
Abstract:
Arsenic (As) is a toxic element released in aquatic environments by geogenic processes
or anthropic activities. To counteract its toxicity, several microorganisms have developed
mechanisms to tolerate and utilize it for respiratory metabolism. However, still little is
known about identity and physiological properties of microorganisms exposed to natural
high levels of As and the role they play in As transformation and mobilization processes.
This work aims to explore the phylogenetic composition and functional properties of
aquatic microbial communities in As-rich freshwater environments of geothermal origin
and to elucidate the key microbial functional groups that directly or indirectly may
influence As-transformations across a natural range of geogenic arsenic contamination.
Distinct bacterial communities in terms of composition and metabolisms were found.
Members of Proteobacteria, affiliated to Alpha- and Betaproteobacteria were mainly
retrieved in groundwaters and surface waters, whereas Gammaproteobacteria were
the main component in thermal waters. Most of the OTUs from thermal waters were
only distantly related to 16S rRNA gene sequences of known taxa, indicating the
occurrence of bacterial biodiversity so far unexplored. Nitrate and sulfate reduction and
heterotrophic As(III)-oxidization were found as main metabolic traits of the microbial
cultivable fraction in such environments. No growth of autotrophic As(III)-oxidizers,
autotrophic and heterotrophic As(V)-reducers, Fe-reducers and oxidizers, Mn-reducers
and sulfide oxidizers was observed. The ars genes, involved in As(V) detoxifying
reduction, were found in all samples whereas aioA [As(III) oxidase] and arrA genes
[As(V) respiratory reductase] were not found. Overall, we found that As detoxification
processes prevailed over As metabolic processes, concomitantly with the intriguing
occurrence of novel thermophiles able to tolerate high levels of As.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
microbiome; thermal waters; detoxification processes; arsenic-related genes; arsenite; arsenate
Elenco autori:
S. Zecchin, A. S., F. S., C. B., A. Corsini, L. Cavalca, R. S.
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