Biochemical and genomic characterization of Chromobacterium violaceum strains isolated from the Tennessee Copper Basin.

摘要

Increasing evidence indicates that bacteria have the ability to prevail in adverse environments and that cross communication between the bacteria and their environment may be responsible for the survival and adaptation of the organisms. To investigate the ability of bacteria to adapt during drastic physical change, recurrent sampling was performed at the Burra Burra copper mine in the Tennessee Copper Basin. Fifty-two (52) bacterial strains were isolated from environmental samples collected from various sites at the mine in Ducktown, Tennessee. Of the microorganisms isolated over a three-year time period, six demonstrated similar cell and colony morphology, Gram reaction, growth rate, colony characteristics, and production of a purple pigment. The determination of each isolates' carbon utilization pattern (CUP) was obtained via the BiologRTM GN2 plate biochemical analysis system and database. The metabolic profiles produced by the GN2 plates identified the organisms as Chromobacterium violaceum. Analysis of optical density maximum (ODm) and the oxidation ability produced by each isolated highlighted marked differences between the metabolic profiles of the isolated bacteria. Observed difference was noted in the marked increased ODm value for the utilization of D-maltose by isolate 14ONP and the decreased utilization of glucose by this isolate. Identification of the Chromobacterium violaceum 14OP, 14ONP, 14N1 and 15O isolates was confirmed by PCR amplification of the first 500 nucleotide base pairs of the 16S rDNA gene of each organism, sequencing of the amplified product, and conducting Basic Local Alignment Search Tool (BLAST) comparison to the National Center of Biotechnological Information (NCBI) database. Sequence alignment analysis of the four Chromobacterium violaceum isolates 16S rDNA showed the level of diversity that existed amongst the organisms, clearly delineating genomic variation amongst isolates 14OP, 14ONP, 14N1 and 15O.