title: Microbe-microbe interactions trigger Mn(II)-oxidizing gene expression.
abstract: Manganese (Mn) is an important metal in geochemical cycles. Some microorganisms can oxidize Mn(II) to Mn oxides, which can, in turn, affect the global cycles of other elements by strong sorption and oxidation effects. Microbe-microbe interactions have important roles in a number of biological processes. However, how microbial interactions affect Mn(II) oxidation still remains unknown. Here, we investigated the interactions between two bacteria (Arthrobacter sp. and Sphingopyxis sp.) in a co-culture, which exhibited Mn(II)-oxidizing activity, although neither were able to oxidize Mn(II) in isolation. We demonstrated that the Mn(II)-oxidizing activity in co-culture was most likely induced via contact-dependent interactions. The expressed Mn(II)-oxidizing protein in the co-culture was purified and identified as a bilirubin oxidase belonging to strain Arthrobacter. Full sequencing of the bilirubin oxidase-encoding gene (boxA) was performed. The Mn(II)-oxidizing protein and the transcripts of boxA were detected in the co-culture, but not in either of the isolated cultures. This indicate that boxA was silent in Arthrobacter monoculture, and was activated in response to presence of Sphingopyxis in the co-culture. Further, transcriptomic analysis by RNA-Seq, extracellular superoxide detection and cell density quantification by flow cytometry indicate induction of boxA gene expression in Arthrobacter was co-incident with a stress response triggered by co-cultivation with Sphingopyxis. Our findings suggest the potential roles of microbial physiological responses to stress induced by other microbes in Mn(II) oxidation and extracellular superoxide production.
authors: Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.|University of Chinese Academy of Sciences, Beijing, China.
authors: Jinsong
authors: J
authors: Liang
authors: Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.
authors: Yaohui
authors: Y
authors: Bai
authors: Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
authors: Yujie
authors: Y
authors: Men
authors: Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.
authors: Jiuhui
authors: J
authors: Qu
mesh_terms: D001173:Arthrobacter / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008345:Manganese / Q000378:metabolism*; D056265:Microbial Interactions; D010084:Oxidation-Reduction; D042301:Sphingomonadaceae / Q000235:genetics / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D008345:Manganese