Evidence for the involvement of intracellular Ca 2+ ions in the elicitation mechanism of Bacillus Licheniformis

Treatment of Bacillus licheniformis cultures with biotic oligosaccharide elicitors is known to increase the production of the antibiotic bacitracin A. The mechanism of the elicitation is currently under investigation and in this paper we provide evidence on the modulatory role of Ca 2+ ions during this process. Addition of elicitors, mannan oligosaccharides, oligoguluronate and oligomannuronate to the liquid cultures resulted in 9.0, 5.2 and 5.0% increase in cytosolic Ca 2+ levels in B. licheniformis , while the presence of verapamil (Ca 2+ channel blocker) resulted in 74% decrease in bacitracin A levels, as compared to the control culture. We propose that Ca 2+ ions may acts as a secondary messenger in the regulation of the bacitracin A synthesis in the elicited B. licheniformis cultures

Enhanced intracellular Ca(2+) concentrations in Escherichia coli and Bacillus subtilis after addition of oligosaccharide elicitors

Elicitation can lead to overproduction of secondary metabolites in plants and microbes. Potential changes in cytosolic Ca(2+) levels in bacteria were studied in response to elicitation. We report, for the first time, the effect of oligosaccharide elicitors on intracellular Ca(2+) levels. The apoaequorin gene was cloned into Escherichia coli DH5α and Bacillus subtilis 1604 cultures. Addition of elicitors, oligoguluronate and mannan oligosaccharides, to the cultures caused up to 11-fold increase in cytosolic Ca(2+) in E. coli and tenfold increase in B. subtilis. These increases in Ca(2+) levels could therefore contribute to the enhancement of secondary metabolite levels