ABSTRACT
The role of oligosaccharides as biotic elicitors has been recognised in the enhanced production of antibiotics from fungal and bacterial cultures. The yield of bacitracin A in cultures of Bacillus licheniformis was increased after supplementation with oligoguluronate (OG), and mannan oligosaccharides (MO) and its mechanism at transcription level been established already. However, the elicitation mechanism at post transcriptional level has not been reported so far. In this paper we investigate changes in proteomics of B. licheniformis in presence of the oligosaccharide elicitors OG and MO. Differentially expressed proteins were examined using 2D-PAGE stained with colloidal Coomassie and were further identified by LC-MS/MS. We identified 19 differentially expressed proteins including those involved in carbon metabolism, energy generation, amino acid biosynthesis, oxidative and general stress response. The novel findings of this work, together with previous reports, contribute to the unravelling of the overall mechanism of elicitation in B. licheniformis cultures and reliability of the use of these elicitors for potential industrial application.
Subject(s)
Bacillus/metabolism , Bacterial Proteins/metabolism , Oligosaccharides/metabolism , Bacitracin/biosynthesis , Carbohydrate Metabolism , Glutamic Acid/metabolism , Hexuronic Acids/metabolism , Industrial Microbiology , Metabolic Networks and Pathways , ProteomicsABSTRACT
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.
