Low Concentrations of Bile Salts Induce Stress Responses and Reduce Motility in
            <i>Bacillus cereus</i>
            ATCC 14579

Kristoffersen, Simen M.; Ravnum, Solveig; Tourasse, Nicolas J.; Økstad, Ole Andreas; Kolstø, Anne‐Brit; Davies, William A.

doi:10.1128/jb.01102-07

Cited by 14 publications

(22 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The chip is a combined Bacillus anthracis/B. cereus microarray containing 7,787 features from B. anthracis strains Ames and A2012 and B. cereus strain ATCC 14579 (33). cDNA samples from swarming populations of B. cereus ATCC 14579 were hybridized against cDNA of B. cereus ATCC 14579 nonswarm cells.…”

Section: Methodsmentioning

confidence: 99%

Global Gene Expression Profile for Swarming Bacillus cereus Bacteria

Salvetti¹,

Fægri

Ghelardi³

et al. 2011

Appl Environ Microbiol

Self Cite

View full text Add to dashboard Cite

Bacillus cereus can use swarming to move over and colonize solid surfaces in different environments. This kind of motility is a collective behavior accompanied by the production of long and hyperflagellate swarm cells. In this study, the genome-wide transcriptional response of B. cereus ATCC 14579 during swarming was analyzed. Swarming was shown to trigger the differential expression (>2-fold change) of 118 genes. Downregulated genes included those required for basic cellular metabolism. In accordance with the hyperflagellate phenotype of the swarm cell, genes encoding flagellin were overexpressed. Some genes associated with K ؉ transport, phBC6A51 phage genes, and the binding component of the enterotoxin hemolysin BL (HBL) were also induced. Quantitative reverse transcription-PCR (qRT-PCR) experiments indicated an almost 2-fold upregulation of the entire hbl operon during swarming. Finally, BC1435 and BC1436, orthologs of liaI-liaH that are known to be involved in the resistance of Bacillus subtilis to daptomycin, were upregulated under swarming conditions. Accordingly, phenotypic assays showed reduced susceptibility of swarming B. cereus cells to daptomycin, and P spac -induced hyper-expression of these genes in liquid medium highlighted the role of BC1435 and BC1436 in the response of B. cereus to daptomycin.

show abstract

Section: Methodsmentioning

confidence: 99%

Global Gene Expression Profile for Swarming Bacillus cereus Bacteria

Salvetti¹,

Fægri

Ghelardi³

et al. 2011

Appl Environ Microbiol

Self Cite

View full text Add to dashboard Cite

show abstract

“…The microarray used was a composite B. cereus-B. anthracis chip that has been described previously (28). For each time point, four arrays were hybridized with quadruplicate independent biological replicates.…”

Section: Methodsmentioning

confidence: 99%

The Global Regulator CodY Regulates Toxin Gene Expression inBacillus anthracisand Is Required for Full Virulence

et al. 2009

View full text Add to dashboard Cite

In gram-positive bacteria, CodY is an important regulator of genes whose expression changes upon nutrient limitation and acts as a repressor of virulence gene expression in some pathogenic species. Here, we report the role of CodY in Bacillus anthracis, the etiologic agent of anthrax. Disruption of codY completely abolished virulence in a toxinogenic, noncapsulated strain, indicating that the activity of CodY is required for full virulence of B. anthracis. Global transcriptome analysis of a codY mutant and the parental strain revealed extensive differences. These differences could reflect direct control for some genes, as suggested by the presence of CodY binding sequences in their promoter regions, or indirect effects via the CodY-dependent control of other regulatory proteins or metabolic rearrangements in the codY mutant strain. The differences included reduced expression of the anthrax toxin genes in the mutant strain, which was confirmed by lacZ reporter fusions and immunoblotting. The accumulation of the global virulence regulator AtxA protein was strongly reduced in the mutant strain. However, in agreement with the microarray data, expression of atxA, as measured using an atxA-lacZ transcriptional fusion and by assaying atxA mRNA, was not significantly affected in the codY mutant. An atxA-lacZ translational fusion was also unaffected. Overexpression of atxA restored toxin component synthesis in the codY mutant strain. These results suggest that CodY controls toxin gene expression by regulating AtxA accumulation posttranslationally.

show abstract

“…The majority of bile (95%) is recycled back into the small intestine and does not enter the colon (10). Concentrations of bile salts range from 0.2% to 2% (wt/vol), depending on the time of day, diet, and individual (11). As reviewed by Ridlon et al, bacterial colonization in the small intestine increases from ϳ10 3 bacteria/ml in the duodenum to 10 4 bacteria/ml in the jejunum and 10 6 to 10 8 bacteria/ml in the ileum.…”

mentioning

confidence: 99%

Survival of the Fittest: How Bacterial Pathogens Utilize Bile To Enhance Infection

et al. 2016

View full text Add to dashboard Cite

SUMMARYBacterial pathogens have coevolved with humans in order to efficiently infect, replicate within, and be transmitted to new hosts to ensure survival and a continual infection cycle. For enteric pathogens, the ability to adapt to numerous host factors under the harsh conditions of the gastrointestinal tract is critical for establishing infection. One such host factor readily encountered by enteric bacteria is bile, an innately antimicrobial detergent-like compound essential for digestion and nutrient absorption. Not only have enteric pathogens evolved to resist the bactericidal conditions of bile, but these bacteria also utilize bile as a signal to enhance virulence regulation for efficient infection. This review provides a comprehensive and up-to-date analysis of bile-related research with enteric pathogens. From common responses to the unique expression of specific virulence factors, each pathogen has overcome significant challenges to establish infection in the gastrointestinal tract. Utilization of bile as a signal to modulate virulence factor expression has led to important insights for our understanding of virulence mechanisms for many pathogens. Further research on enteric pathogens exposed to thisin vivosignal will benefit therapeutic and vaccine development and ultimately enhance our success at combating such elite pathogens.

show abstract

Low Concentrations of Bile Salts Induce Stress Responses and Reduce Motility in Bacillus cereus ATCC 14579

Cited by 14 publications

References 0 publications

Global Gene Expression Profile for Swarming Bacillus cereus Bacteria

Global Gene Expression Profile for Swarming Bacillus cereus Bacteria

The Global Regulator CodY Regulates Toxin Gene Expression inBacillus anthracisand Is Required for Full Virulence

Survival of the Fittest: How Bacterial Pathogens Utilize Bile To Enhance Infection

Contact Info

Product

Resources

About