Signaling and Genetic Studies of Chromobacterium violaceum

Sydnee Trabue, Tennessee State University


Strains of Chromobacterium violaceum (CV) isolated from the Tennessee Copper Mining Site in Ducktown, TN were identified using carbon utilization patterns in previous studies. In this study, these strains 14OP, 14ONP, 14N23 and 14N1 were compared to the mutant strain CVO26 and strain ATCC 12472 whose genome has been sequenced. CVO26 is a mutant that lacks the ability to produce N-hexanoyl-L-homoserine lactone (HHL), which is required for production of the pigment violacein. The isolates were tested for HHL production by growing CVO26 in the presence of the isolates and growth media preparations from the isolates. These studies have shown that the strains isolated from the Copper Basin do not contain the proper HHL to cause CVO26 to produce pigment. The 16S rDNA gene of each of the CV strains was amplified, sequenced and fragments linked to establish the 1600 base pair gene. The sequences were further analyzed using ClustalW and T-Coffee programs to ultimately generate a phylogenetic tree to view the relationship of the strains to one another. It was found that the strains of 14OP and 14N1 mapped in a cluster with both CVO26 and ATCC 12472. The 14ONP strain mapped near the cluster and 14N23 mapped distantly away from the other strains. A BLAST search of the 16s rDNA gene sequence that was isolated proved that all strains isolated from the Tennessee Copper Basin are at least 93% similar to organism Chromobacterium subtsugae. The BLAST result sequences were selected and assessed through T-coffee alignments to establish the relationship of all 16s sequences. These data showed that these strains were 97% similar to strain 14N23 and ATCC 12472 Thus, it was concluded that all the strains including C. subtsugae were actually C. violacein strains and not separate species.

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Recommended Citation

Sydnee Trabue, "Signaling and Genetic Studies of Chromobacterium violaceum" (2013). ETD Collection for Tennessee State University. Paper AAI3587650.