Genome sequence of a proteolytic (Group I) Clostridium botulinum strain Hall A and comparative analysis of the clostridial genomes

Abstract

Clostridium botulinum is a heterogeneous Gram-positive species that comprises four genetically and physiologically distinct groups of bacteria that share the ability to produce botulinum neurotoxin, the most poisonous toxin known to man, and the causative agent of botulism, a severe disease of humans and animals. We report here the complete genome sequence of a representative of Group I (proteolytic) C. botulinum (strain Hall A, ATCC 3502). The genome consists of a chromosome (3,886,916 bp) and a plasmid (16,344 bp), which carry 3650 and 19 predicted genes, respectively. Consistent with the proteolytic phenotype of this strain, the genome harbors a large number of genes encoding secreted proteases and enzymes involved in uptake and metabolism of amino acids. The genome also reveals a hitherto unknown ability of C. botulinum to degrade chitin. There is a significant lack of recently acquired DNA, indicating a stable genomic content, in strong contrast to the fluid genome of Clostridium difficile, which can form longer-term relationships with its host. Overall, the genome indicates that C. botulinum is adapted to a saprophytic lifestyle both in soil and aquatic environments. This pathogen relies on its toxin to rapidly kill a wide range of prey species, and to gain access to nutrient sources, it releases a large number of extracellular enzymes to soften and destroy rotting or decayed tissues.

Lipid diversity among botulinum neurotoxin-producing clostridia

“…Group I strains are closely related to C. sporogenes and more distantly related to C. tetani Hill et al, 2007;Sebaihia et al, 2007). In addition to PG, CL and PE, phospholipids that are found in all strains of C. botulinum that we have examined, group I strains contain low amounts of EtnPGlcNAcDRG, which was detected by MS of the total lipids.…”

“…A(B) (Franciosa et al, 1994). Human botulism is commonly caused by groups I and II C. botulinum (Sebaihia et al, 2007). Other species of clostridia have been isolated that produce BoNTs, including Clostridium argentinense, and rare strains of Clostridium baratii and Clostridium butyricum (Hatheway & Johnson, 1998).…”

Important Role of Class I Heat Shock Genes hrcA and dnaK in the Heat Shock Response and the Response to pH and NaCl Stress of Group I Clostridium botulinum Strain ATCC 3502

“…This suggests that C. botulinum possesses rapid and effective measures to overcome temperature stress. Interestingly, no evidence for the presence of a B -dependent general stress regulon, which plays a major role in the heat shock and general stress response of B. subtilis and many other Gram-positive bacteria (6), can be found in the C. botulinum ATCC 3502 genome (21).…”

“…To date, the chaperone DnaJ has been identified in a C. botulinum type A strain (23), and the chaperone GroEL and its cochaperone GroES have been characterized in a C. botulinum type D strain (16). Besides the genes coding for DnaJ, GroEL, and GroES, the published genome sequence of C. botulinum strain ATCC 3502 suggests the presence of genes coding for GrpE, a heat shock protein, HrcA, the negative regulator of class I HSGs, and DnaK, a major molecular chaperone (21). These genes are organized in the dnaK and the groE operons (21).…”

Flagellar Glycosylation: Current Advances

“…Structural characterization of the carbohydrate moiety from C. botulinum flagellin has been achieved, and it was shown to be composed of the Leg derivative, 7-acetamido-5-(N-methylglutam-4-yl)-amino-3,5,7,9-tetradeoxy-d-glycero--d-galacto-nonulosonic acid ( Leg5GluNMe7Ac) (Twine et al, 2008). For the C. botulinum strain Langeland, a bioinformatic analysis of the flagella glycosylation island was completed between flgB and fliD as a large gene cluster (~48 kb), many of which appeared to be involved in carbohydrate biosynthesis (Sebaihia et al, 2007). This glycosylation island could be divided into two regions, a variable region which was located immediately downstream of the flagellin gene, and a subsequent conserved region.…”