The Heavy-Metal Resistance Determinant of Newly Isolated Bacterium from a Nickel-Contaminated Soil in Southwest Slovakia

摘要

A bacterial isolate MR-CH-I2 [ ] isolated from soil contaminated mainly by high nickel concentrations in southwest Slovakia was previously found carrying A-like heavy-metal resistance determinant, marked as MR-CH-I2-HMR [ ]. According to phylogenetic analysis of short (696 bp) 16S rDNA (16S rRNA) sequences this bacterium was tentatively assigned to Uncultured beta proteobacterium clone GC0AA7ZA05PP1 [ ]. A-like gene product was on the same base of its partial (581 bp) sequences tentatively assigned to CzcA family heavy metal efflux pump [ ] from 12J with 99% similarity. In this study the bacterium MR-CH-I2 and its heavy-metal resistance determinant were more precisely identified. This bacterial isolate was on the base of phylogenetic analysis of almost the whole (1,500 bp) 16S rDNA (16S rRNA) sequence, MR-CH-I2 [ ], and sequence for B gene and its product respectively, MR-CH-I2-gyrB [ ], assigned to 12J [ ] with 99 and 100% similarities, respectively. In addition, the whole A-like heavy-metal resistance gene sequence (3,192 bp), marked as MR-CH-I2-nccA [ ], was obtained and on the base of phylogenetic analysis its assignment was confirmed to MULTISPECIES: cation efflux system protein CzcA [ ] from Burkholderiaceae with 98% similarity. Furthermore, although the bacterium carried one high molecular plasmid of about 50 kb in size, A-like gene was not located on this plasmid. Finally, the results from RT-PCR analysis showed that MR-CH-I2-nccA gene was significantly induced only by the addition of nickel.