Project description:AtxA, the master virulence regulator of Bacillus anthracis, regulates the expression of three toxins that are required for the pathogenicity of Bacillus anthracis. Recent transcriptome analyses also showed that AtxA affects a large number of genes on both chromosome and plasmid, suggesting its role as a global regulator. Its mechanism of gene regulation nor binding target in vivo was, however, not well understood. In this work, we conducted ChIP-seq for cataloging binding sites of AtxA in vivo and Cappable-seq for catalogging the transcription start sites on the B. anthracis genome. For detected regulons, single knockout strains were constructed and RNA-seq was conducted for each strain.
Project description:Investigation of whole genome expression level changes in Bacillus anthracis Sterne deltaClpX mutant compared to the wild-type strain after growth in nutrient rich media. The deltaClpX mutant used in this study is described in McGillivray et al. 2009. ClpX Protease Contributes to Antimicrobial Peptide Resistance and Virulence Phenotypes of Bacillus anthracis. Journal of Innate Immunity 1(5): 494-506.
Project description:Anthrax is a zoonotic infection caused by the bacterium Bacillus anthracis (BA), a gram-positive, aerobic, spore-forming bacterium that can be misused as a biowarfare agent. The major patho-genicity factors of BA are encoded by genes located on two extrachromosomal plasmids, which are often targeted for specific identification of this pathogen. However, more recent findings show that these plasmids are not a unique feature of BA but can also occur in other Bacillus species. Furthermore, BA is a member of the Bacillus cereus group, a subgroup of closely related Bacilli. Due to the high genetic similarity within this group, it is a challenge to distinguish BA from other members of this group. In this study, we investigated if it is possible to identify species-specific and universally applicable marker peptides for BA. For this purpose, we applied a high-resolution mass spectrometry-based approach for 42 BA isolates. Together with the genomic sequencing data and by developing a bioinformatics data evaluation pipeline, which uses a database containing most of the publicly available protein sequences worldwide (UniParc), we were able to identify eleven universal marker peptides unique to BA, which are located on the chromosome and there-fore might overcome known problems like observable loss of plasmids in environmental species, plasmid loss during cultivation in the lab and that the virulence plasmids are not necessarily a unique feature of BA. The identified chromosomally encoded markers in this study could extend the small panel of already existing chromosomal targets and together with targets for the viru-lence plasmids may pave the way to an even more reliable identification of BA using genomics- as well as proteomics-based techniques.
Project description:Bacillus anthracis causes anthrax infections in mammals. Large-scale mortality resulting from the intentional release of B. anthracis spores represents a potential bioterrorism threat. Inhalational anthrax almost invariably proceeds to fatal systemic infection, characterized by massive bacteremia. A better understanding of host-pathogen interactions is urgently needed for effective treatment of this lethal disease. However, virulence mechanisms used by B. anthracis to survive and multiply in human blood are not completely understood. Identification of genes that are differentially expressed during the growth of B. anthracis in human serum can elucidate how this pathogen successfully colonizes the bloodstream. We compared the transcriptional profile of B. anthracis growing in heat-inactivated human serum to that in LB medium. Genes involved in the biosynthesis of purines, certain amino acids and riboflavin and lipid metabolism, genes encoding ABC transporters, respiratory enzymes and several genes with hypothetical function were identified as being upregulated during growth in serum.
Project description:The aim of the study was to carry out a CGH study utilizing a set of 39 diverse Bacillus isolates. Thirty four B. cereus and five B. anthracis strains and isolates were chosen so as to represent different lineages based on previous characterizations, including MLEE and MLST (Helgason, Okstad et al. 2000; Helgason, Tourasse et al. 2004). They represent the spectrum of B. cereus phenotypic diversity by including soil, dairy and periodontal isolates in addition to virulent B. anthracis strains.
Project description:5-methylcytosine is one of the major epigenetic modifications of DNA in living organisms. In bacteria, some species possess DNA methyltransferases that produce the cytosine modification in both strands or either strand of its target sequence. The purpose of this study is to characterize BatIM, the orphan cytosine methyltransferase coded on a prophage region of Bacillus anthracis.