title: Alkane inducible proteins in Geobacillus thermoleovorans B23.
abstract: BACKGROUND
  Initial step of beta-oxidation is catalyzed by acyl-CoA dehydrogenase in prokaryotes and mitochondria, while acyl-CoA oxidase primarily functions in the peroxisomes of eukaryotes. Oxidase reaction accompanies emission of toxic by-product reactive oxygen molecules including superoxide anion, and superoxide dismutase and catalase activities are essential to detoxify them in the peroxisomes. Although there is an argument about whether primitive life was born and evolved under high temperature conditions, thermophilic archaea apparently share living systems with both bacteria and eukaryotes. We hypothesized that alkane degradation pathways in thermophilic microorganisms could be premature and useful to understand their evolution.
  
  
  RESULTS
  An extremely thermophilic and alkane degrading Geobacillus thermoleovorans B23 was previously isolated from a deep subsurface oil reservoir in Japan. In the present study, we identified novel membrane proteins (P16, P21) and superoxide dismutase (P24) whose production levels were significantly increased upon alkane degradation. Unlike other bacteria acyl-CoA oxidase and catalase activities were also increased in strain B23 by addition of alkane.
  
  
  CONCLUSIONS
  We first suggested that peroxisomal beta-oxidation system exists in bacteria. This eukaryotic-type alkane degradation pathway in thermophilic bacterial cells might be a vestige of primitive living cell systems that had evolved into eukaryotes.
authors.affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan. tkato@iis.u-tokyo.ac.jp
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Kato
authors.forename: Asuka
authors.initials: A
authors.lastname: Miyanaga
authors.forename: Shigenori
authors.initials: S
authors.lastname: Kanaya
authors.forename: Masaaki
authors.initials: M
authors.lastname: Morikawa