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Plasmids carry some genes responsible for botulinum neurotoxins In collaboration among the Bioscience Division, Theoretical Division and the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), scientists recently discovered that some of the genes responsible for producing the extremely potent botulinum neurotoxins of the bacteria Clostridium botulinum are found within extra-chromosomal elements, called plasmids. The project, led by Tom Brettin (B-6), Karen Hill (B-7), and Theresa Smith (USAMRIID) sequenced several strains of C. botulinum that produce different neurotoxin types and subtypes. One strain, which produced two different toxin types, was found to contain both of the toxin genes within the same plasmid—the first molecular characterization of a bivalent strain of C. botulinum. The plasmids containing the toxin genes were found to share significant sequence identity to each other. The study also identified the presence of partial insertion sequence elements and found evidence of recombination and gene duplication events in regions flanking the toxin genes. The sequence data of these different strains will help researchers in diagnostics, detection and treatment of botulism and furthers the understanding of the different mechanisms by which these genes move among diverse genetic backgrounds of C. botulinum. This research has been published: T. J. Smith, K. K. Hill, B. T. Foley, J. C. Detter, A. C. Munk, D. C. Bruce, N. A. Doggett, L. A. Smith, J. D. Marks, G. Xie, T. S. Brettin. “Analysis of the Neurotoxin Complex Genes in Clostridium botulinum A1-A4 and B1 Strains: BoNT/A3, /Ba4 and /B1 Clusters Are Located within Plasmids”, PLoS ONE. 2007 Dec 5; 2(12). The DOE Joint Genome Institute (JGI) at Los Alamos received support from the Intelligence Technology Innovation Center for this work. From this support JGI sequenced the different strains that led to the discoveries in the paper. |
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