Identification and distribution

of the arsenite oxidase gene aoxB and arsenite transporter genes arsB, ACR3(1) and ACR3(2) A total of 5 arsenite oxidase genes and 51 arsenite transporter genes were successfully LY3039478 amplified from 38 strains using PCR with degenerate primers. The ACR3(1) and ACR3(2) were amplified in strains of the high and intermediate arsenic-contaminated soils only. In contrast, aoxB and arsB were found in strains isolated from all three kinds of arsenic-contaminated environments (Fig. 1). Strains containing both an arsenite oxidase gene (aoxB) and an arsenite transporter gene (ACR3 or arsB) showed a higher average arsenite resistance level than the strains possessing arsenite transporter genes only

[aoxB/ACR3 (20.25 mM) ≈ aoxB/arsB Thiazovivin in vitro (20 mM) > arsB/ACR3 (14.29 mM) ≈ ACR3 (14.13 mM) > arsB (10.1 mM)]. The aoxB sequences were amplified from all of the five arsenite oxidizers. No aoxB sequences were amplified from any of the 53 non-arsenite oxidizers. The deduced amino acid sequence of aoxB from Achromobacter sp. SY8 showed 95% identity to AoxB selleck chemical from Achromobacter sp. NT-10 (GenBank accession no. ABD72610) [15]. The deduced AoxBs from Agrobacterium spp. TS43, TS45, and LY4 displayed 95%, 96%, and 95% identities to AoxB of Agrobacterium tumefaciens 5A (GenBank accession no. ABB51928) [31], and 94%, 96%, and 95% identities to AoxB from Rhizobium sp. NT26 (GenBank accession no. AAR05656) [14] respectively. The identity of AoxBs between Pseudomonas sp. TS44

and Alcaligenes faecalis NCIB 8687 was only 61% (Fig. 2). Comparison between 16S rDNA and deduced AoxB phylogenetic trees indicated that their evolutionary relationship was similar. Figure 2 Phylogenetic tree of arsenite oxidase (AoxB). Phylogenetic analysis of the deduced amino acid sequences (~160 aa) of aoxB genes. Sequences Fossariinae in this study are in bold type and bootstrap values over 50% are shown. The scale bar 0.05 means 5% aa sequence substitution. Analyses of arsenite transporter genes using the BlastX algorithm showed proteins with 71%–80% aa identities that contained 2 ArsB and 6 Acr3(2)p, 81%–90% aa identities had 10 ArsB, 5 Acr3(1)p and 11 Acr3(2)p, aa identities over 90% included 6 ArsB, 7 Acr3(1)p and 4 Acr3(2)p. The arsB, ACR3(1), and ACR3(2) were amplified from both the arsenite oxidizers and non-arsenite oxidizers. The strains containing 2 arsenite transporter genes simultaneously were Pseudomonas sp. SY7 [arsB and ACR3(1)], Shewanella sp. TS29, Delftia spp. TS12, TS30, TS33, TS41 and Pseudomonas sp. SY4 [arsB and ACR3(2)], Stenotrophomonas spp. TS28, SY1, SY2, Aeromonas spp. TS26, TS36 and Pseudomonas sp. TS44 [ACR3(1) and ACR3(2)] (Fig. 1).