Research article
Identification of Bacillus anthracis specific chromosomal sequences by suppressive subtractive hybridization
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* Corresponding author: Vito G DelVecchio vdelvecchio@vitalprobes.com
1 Loyola Hall of Science, University of Scranton, Scranton, Pennsylvania 18510, USA
2 Institute of Molecular Biology and Medicine, University of Scranton, Scranton, Pennsylvania 18510, USA
3 Present address: Schott Glass Technologies Inc. 400 York Avenue, Duryea, PA 18642, USA
4 Present address: Vital Probes, Inc., 1300 Old Plank Road, Mayfield, PA 18433, USA
BMC Genomics 2004, 5:15 doi:10.1186/1471-2164-5-15
Published: 12 February 2004Abstract
Background
Bacillus anthracis, Bacillus thuringiensis and Bacillus cereus are closely related members of the B. cereus-group of bacilli. Suppressive subtractive hybridization (SSH) was used to identify specific chromosomal sequences unique to B. anthracis.
Results
Two SSH libraries were generated. Genomic DNA from plasmid-cured B. anthracis was used as the tester DNA in both libraries, while genomic DNA from either B. cereus or B. thuringiensis served as the driver DNA. Progressive screening of the libraries by colony filter and Southern blot analyses identified 29 different clones that were specific for the B. anthracis chromosome relative not only to the respective driver DNAs, but also to seven other different strains of B. cereus and B. thuringiensis included in the process. The nucleotide sequences of the clones were compared with those found in genomic databases, revealing that over half of the clones were located into 2 regions on the B. anthracis chromosome.
Conclusions
Genes encoding potential cell wall synthesis proteins dominated one region, while bacteriophage-related sequences dominated the other region. The latter supports the hypothesis that acquisition of these bacteriophage sequences occurred during or after speciation of B. anthracis relative to B. cereus and B. thuringiensis. This study provides insight into the chromosomal differences between B. anthracis and its closest phylogenetic relatives.