title: Genomic Analysis Unravels Reduced Inorganic Sulfur Compound Oxidation of Heterotrophic Acidophilic Acidicaldus sp. Strain DX-1.
abstract: Although reduced inorganic sulfur compound (RISC) oxidation in many chemolithoautotrophic sulfur oxidizers has been investigated in recent years, there is little information about RISC oxidation in heterotrophic acidophiles. In this study, Acidicaldus sp. strain DX-1, a heterotrophic sulfur-oxidizing acidophile, was isolated. Its genome was sequenced and then used for comparative genomics. Furthermore, real-time quantitative PCR was performed to identify the expression of genes involved in the RISC oxidation. Gene encoding thiosulfate: quinone oxidoreductase was present in Acidicaldus sp. strain DX-1, while no candidate genes with significant similarity to tetrathionate hydrolase were found. Additionally, there were genes encoding heterodisulfide reductase complex, which was proposed to play a crucial role in oxidizing cytoplasmic sulfur. Like many heterotrophic sulfur oxidizers, Acidicaldus sp. strain DX-1 had no genes encoding enzymes essential for the direct oxidation of sulfite. An indirect oxidation of sulfite via adenosine-5'-phosphosulfate was proposed in Acidicaldus strain DX-1. However, compared to other closely related bacteria Acidiphilium cryptum and Acidiphilium multivorum, which harbored the genes encoding Sox system, almost all of these genes were not detected in Acidicaldus sp. strain DX-1. This study might provide some references for the future study of RISC oxidation in heterotrophic sulfur-oxidizing acidophiles.
authors.affiliation: School of Materials and Metallurgy, Northeastern University, Shenyang, China; CNMC Luanshya Copper Mines Plc. (CLM), Luanshya, Zambia.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Materials and Metallurgy, Northeastern University, Shenyang, China.
authors.forename: Hongying
authors.initials: H
authors.lastname: Yang
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, China.
authors.forename: Xian
authors.initials: X
authors.lastname: Zhang
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, China.
authors.forename: Yunhua
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Guo
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, China.
authors.forename: Xueduan
authors.initials: X
authors.lastname: Liu
mesh_terms: D020561:Alphaproteobacteria / Q000235:genetics* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D023281:Genomics / Q000379:methods*; D052836:Heterotrophic Processes; D006862:Hydrogen Sulfide / Q000378:metabolism; D007287:Inorganic Chemicals / Q000378:metabolism*; D008954:Models, Biological; D058977:Molecular Sequence Annotation; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D013455:Sulfur / Q000378:metabolism*
chemical_list: D007287:Inorganic Chemicals; D012336:RNA, Ribosomal, 16S; D013455:Sulfur; D010088:Oxidoreductases; D006862:Hydrogen Sulfide