Discovery of a Novel Gene Conferring Tellurite Tolerance Through Tellurite Reduction to Escherichia coli Transformant in Marine Sediment Metagenomic Library
Metagenomic library construction using a marine sediment-enrichment was employed in order to recover tellurium from tellurite, a tellurium oxyanion, dissolved in water and then functional screening was performed to discover a novel gene related to tellurite reduction. Transmission electron microscopy (TEM) revealed the formation of intracellular Te crystals in Escherichia coli cells transformed with a specific DNA fragment from the marine sediment metagenome. The metagenome fragment was composed of 691 bp and showed low homology to known proteins. Phylogenetic analysis suggested that the metagenome fragment was related to Pseudomonas stutzeri. Cloning and expression of an open reading frame (ORF) on the metagenome fragment validated the role of the fragment in conferring tellurite resistance and tellurite-reducing activity to E. coli host cells. E. coli transformant containing the ORF1 showed resistance to 1 mM Na2TeO3. The optimal tellurite-reducing activity of cells containing the ORF1 was recorded at 37 °C and pH 7.0.
KeywordsMetagenome library Marine sediment Metalloid tellurium Tellurite reduction
The marine sediment sample was generously provided by Dr. Takeshi Terahara of the Tokyo University of Marine Science and Technology, Japan.
This work was supported by the research budgets of Hiroshima University. Madison Munar received financial support for his Ph.D. from the Top Global University Project Scholarship of the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) Japan.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
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