title: Gene expression modulation by heat stress in Acidithiobacillus ferrooxidans LR.
abstract: During bioleaching, Acidithiobacillus ferrooxidans is subjected to different types of stress, including heat stress, which affect bacterial growth. In this work, real time quantitative PCR was used to analyze the expression of heat shock genes, as well as genes that encode proteins related to several functional categories in A. ferrooxidans. Cells were submitted to long-term growth and heat shock, both at 40°C. The results showed that heat shock affected the expression levels of most genes investigated, whilst long-term growth at 40°C resulted in minor changes in gene expression, except for certain genes related to iron transport, which were strongly down-regulated, suggesting that the iron processing capability of A. ferrooxidans was affected by long-term growth at 40°C. A bioinformatic analysis of the genes' promoter regions indicated a putative transcriptional regulation by the σ(32) factor in 12 of the 31 genes investigated, suggesting the involvement of other regulatory mechanisms in the response of A. ferrooxidans to heat stress.
authors.affiliation: Center for Molecular Biology and Genetic Engineering, State University of Campinas, Campinas, SP, Brazil.
authors.forename: Daniela A
authors.initials: DA
authors.lastname: Ribeiro
authors.forename: Lúcio F C
authors.initials: LF
authors.lastname: Ferraz
authors.forename: Renato
authors.initials: R
authors.lastname: Vicentini
authors.forename: Laura M M
authors.initials: LM
authors.lastname: Ottoboni
mesh_terms: D042763:Acidithiobacillus / Q000235:genetics* / Q000254:growth & development; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D001665:Binding Sites; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics; D003067:Coenzymes / Q000235:genetics; D016384:Consensus Sequence; D004734:Energy Metabolism / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D006358:Hot Temperature; D007501:Iron / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012329:RNA, Bacterial / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012808:Sigma Factor / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D003067:Coenzymes; D006360:Heat-Shock Proteins; D012329:RNA, Bacterial; D012808:Sigma Factor; C069774:heat-shock sigma factor 32; D007501:Iron