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Bacillus anthracis
About: Bacillus anthracis is a research topic. Over the lifetime, 3994 publications have been published within this topic receiving 128122 citations.
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TL;DR: It is shown that transcription of atx A does not appear to differ in cells grown in 5% CO2 compared with cells growing in air, and the antibody response to all three toxin proteins is decreased significantly in atX A‐null mutant‐infected mice, suggesting that the atx B gene product also regulates toxin gene expression during infection.
Abstract: Bacillus anthracis plasmid pXO1 carries the structural genes for the three anthrax toxin proteins, cya (edema factor), lef (lethal factor), and pag (protective antigen). Expression of the toxin genes by B. anthracis is enhanced during growth under elevated levels of CO2. This CO2 effect is observed only in the presence of another pXO1 gene, atxA, which encodes a transactivator of anthrax toxin synthesis. Here we show that transcription of atxA does not appear to differ in cells grown in 5% CO2 compared with cells grown in air. Using a new efficient method for gene replacement in B. anthracis, we constructed an atxA-null mutant in which the atxA-coding sequence on pXO1 is replaced with an omega km-2 cassette. Transcription of all three toxin genes is decreased in the absence of atxA. The pag gene possesses two apparent transcription start sites, P1 and P2; only transcripts with 5' ends mapping to P1 are decreased in the atxA-null mutant. Deletion analysis of the pag promoter region indicates that the 111 bp region upstream of the P1 site is sufficient for atxA-mediated activation of this transcript. The cya and lef genes each have one apparent start site for transcription. Transcripts with 5' ends mapping to these sites are not detected in the atxA-null mutant. The atxA-null mutant is avirulent in mice. Moreover, the antibody response to all three toxin proteins is decreased significantly in atxA-null mutant-infected mice. These data suggest that the atxA gene product also regulates toxin gene expression during infection.
161 citations
TL;DR: A factor in the plasma of guinea pigs dying of anthrax which is not only lethal but also specifically neutralized by anthrax antiserum is demonstrated.
Abstract: AN enigma in the study of the cause of death in anthrax has been that no lethal endo- or exo-toxin has been found in cultures of the organism1–3. Recently, we have been able to demonstrate a factor in the plasma of guinea pigs dying of anthrax which is not only lethal but also specifically neutralized by anthrax antiserum. This communication describes briefly work which has led to this finding. A fuller report will be published elsewhere.
161 citations
TL;DR: Three Bacillus anthracis Sterne strains (USAMRIID, 7702, and 34F2) and Bacillus cereus ATCC 14579 excrete two catecholate siderophores, petrobactin and bacillibactin, which may be prevalent in strains with pathogenic potential for vertebrates.
159 citations
TL;DR: In the case of the outbreak of human anthrax in Sverdlovsk, Union of Soviet Socialists Republic (now Ekaterinburg, Russia) in April 1979, DNA was extracted from 11 victims and extracted DNA was analyzed by using PCR to determine whether it contained Bacillus anthracis specific sequences as mentioned in this paper.
Abstract: An outbreak of human anthrax occurred in Sverdlovsk, Union of Soviet Socialists Republic (now Ekaterinburg, Russia) in April 1979. Officials attributed this to consumption of contaminated meat, but Western governments believed it resulted from inhalation of spores accidentally released from a nearby military research facility. Tissue samples from 11 victims were obtained and methods of efficiently extracting high-quality total DNA from these samples were developed. Extracted DNA was analyzed by using PCR to determine whether it contained Bacillus anthracis-specific sequences. Double PCR using “nested primers” increased sensitivity of the assay significantly. Tissue samples from 11 persons who died during the epidemic were examined. Results demonstrated that the entire complement of B. anthracis toxin and capsular antigen genes required for pathogenicity were present in tissues from each of these victims. Tissue from a vaccination site contained primarily nucleic acids from a live vaccine, although traces of genes from the infecting organisms were also present. PCR analysis using primers that detect the vrrA gene variable region on the B. anthracis chromosome demonstrated that at least four of the five known strain categories defined by this region were present in the tissue samples. Only one category is found in a single B. anthracis strain.
158 citations
TL;DR: The patient's clinical course was characterized by progression of respiratory insufficiency, pleural effusions and pulmonary edema, and, ultimately, death, and viable B anthracis was present in postmortem mediastinal lymph node specimens.
Abstract: We describe the 11th case of bioterrorism-related inhalational anthrax reported in the United States. The presenting clinical features of this 94-year-old woman were subtle and nondistinctive. The diagnosis was recognized because blood cultures were obtained prior to administration of antibiotics, emphasizing the importance of this diagnostic test in evaluating ill patients who have been exposed to Bacillus anthracis. The patient's clinical course was characterized by progression of respiratory insufficiency, pleural effusions and pulmonary edema, and, ultimately, death. Although her B anthracis bacteremia was rapidly sterilized after initiation of antibiotic therapy, viable B anthracis was present in postmortem mediastinal lymph node specimens. The source of exposure to B anthracis in this patient is not known. Exposure to mail that was cross-contaminated as it passed through postal facilities contaminated with B anthracis spores is one hypothesis under investigation.
157 citations