title: Aerobic conditions increase isoprenoid biosynthesis pathway gene expression levels for carotenoid production in Enterococcus gilvus.
abstract: Some lactic acid bacteria that harbour carotenoid biosynthesis genes (crtNM) can produce carotenoids. Although aerobic conditions can increase carotenoid production and crtNM expression levels, their effects on the pathways that synthesize carotenoid precursors such as mevalonate and isoprene are not completely understood. In this study, we investigated whether aerobic conditions affected gene expression levels involved in the isoprenoid biosynthesis pathway that includes the mevalonate and isoprene biosynthesis pathways in Enterococcus gilvus using real-time quantitative reverse transcription PCR. NADH oxidase (nox) and superoxide dismutase (sod) gene expression levels were investigated as controls for aerobic conditions. The expression levels of nox and sod under aerobic conditions were 7.2- and 8.0-fold higher, respectively, than those under anaerobic conditions. Aerobic conditions concomitantly increased the expression levels of crtNM carotenoid biosynthesis genes. HMG-CoA synthase gene expression levels in the mevalonate pathway were only slightly increased under aerobic conditions, whereas the expression levels of HMG-CoA reductase and five other genes in the isoprene biosynthesis pathways were 1.2-2.3-fold higher than those under anaerobic conditions. These results demonstrated that aerobic conditions could increase the expression levels of genes involved in the isoprenoid biosynthesis pathway via mevalonate in E. gilvus.
authors.affiliation: Animal Products Research Division, NARO Institute of Livestock and Grassland Science, Ibaraki, Japan thagi@affrc.go.jp.
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Hagi
authors.affiliation: Animal Products Research Division, NARO Institute of Livestock and Grassland Science, Ibaraki, Japan.
authors.forename: Miho
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: Animal Products Research Division, NARO Institute of Livestock and Grassland Science, Ibaraki, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Nomura
mesh_terms: D000332:Aerobiosis; D002338:Carotenoids / Q000096:biosynthesis / Q000235:genetics*; D016983:Enterococcus / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D006903:Hydroxymethylglutaryl CoA Reductases / Q000235:genetics; D008798:Mevalonic Acid / Q000378:metabolism; D009097:Multienzyme Complexes / Q000235:genetics; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics; D018384:Oxidative Stress / Q000502:physiology; D010100:Oxygen / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000235:genetics; D013729:Terpenes / Q000378:metabolism*
chemical_list: D009097:Multienzyme Complexes; D013729:Terpenes; D002338:Carotenoids; D006903:Hydroxymethylglutaryl CoA Reductases; D013482:Superoxide Dismutase; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D008798:Mevalonic Acid; D010100:Oxygen
keywords: aerobic; carotenoid; gene expression; isoprene; lactic acid bacteria; mevalonate