Affiliation:
1. State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China
Abstract
ABSTRACT
Acidithiobacillus ferrooxidans
is a major participant in consortia of microorganisms used for bioleaching. It can obtain energy from the oxidation of Fe
2+
, H
2
, S
0
, and various reduced inorganic sulfur compounds (RISCs). Tetrathionate is a key intermediate during RISC oxidation, hydrolyzed by tetrathionate hydrolase (TetH), and used as sole energy source. In this study, a
tetH
knockout (Δ
tetH
) mutant and a
tetH
overexpression strain were constructed and characterized. The
tetH
overexpression strain grew better on sulfur and tetrathionate and possessed a higher rate of tetrathionate utilization and TetH activity than the wild type. However, its cell yields on tetrathionate were much lower than those on sulfur. The Δ
tetH
mutant could not grow on tetrathionate but could proliferate on sulfur with a lower cell yield than the wild type's, which indicated that tetrathionate hydrolysis is mediated only by TetH, encoded by
tetH
. The Δ
tetH
mutant could survive in ferrous medium with an Fe
2+
oxidation rate similar to that of the wild type. For the
tetH
overexpression strain, the rate was relatively higher than that of the wild type. The reverse transcription-quantitative PCR (qRT-PCR) results showed that
tetH
and
doxD2
acted synergistically, and
doxD2
was considered important in thiosulfate metabolism. Of the two
sqr
genes, AFE_0267 seemed to play as important a role in sulfide oxidation as AFE_1792. This study not only provides a substantial basis for studying the function of the
tetH
gene but also may serve as a model to clarify other candidate genes involved in sulfur oxidation in this organism.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
35 articles.
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