Mercury Resistance and Removal Mechanisms of Pseudomonas sp. Isolated Mercury-contaminated Site in Taiwan

Abstract

A new strain of Pseudomonas sp. was isolated from mercury (Hg)-contaminated sites in Taiwan. This bacterium removed more than 80% of Hg present in the culture medium at 12 h incubation and was chosen for further analysis of the molecular mechanisms of Hg tolerance/removal abilities in this Pseudomonas sp. We used RNA-seq, one of the nextgeneration sequencing methods, to investigate the transcriptomic responses of the Pseudomonas sp. exposed to 60 mg/L of Hg 2+. We de novo assembled 4,963 contigs, of which 10,533 up-regulated genes and 5,451 down-regulated genes were found to be regulated by Hg. The 40 genes most altered in expression levels were associated with tolerance to Hg stress and metabolism. Functional analysis showed that some Hg-tolerant genes were related to the mer operon, sulfate uptake and assimilation, the enzymatic antioxidant system, the HSP gene family, chaperones, and metal transporters. The transcriptome were analyzed further with Gene Ontology (GO) and Cluster of Orthologous Groups (COGs) of proteins and showed diverse biological functions and metabolic pathways under Hg stress.

Draft genome sequence of Pseudomonas sp. A46 isolated from mercury‐contaminated wastewater

“…Pseudomonas sp. A46 was isolated from a former chlor‐alkali manufacturing plant in Southern Taiwan that was contaminated with mercury (Hg), polychlorinated dibenzo‐p‐dioxins (PCDDs), and octa‐chlorinated dioxins (OCDDs) [5]. Pseudomonas sp.…”

“…Pseudomonas sp. A46 has been proven to tolerate/metabolize 60 ppm of Hg within a 24 h of incubation period [5]. Identification of the draft genome sequence of this bacterium could provide more information on the genetic characteristics associated with resistance to multiple heavy metals in addition to Hg.…”