Root Microbiology
Short introduction to PhD thesis:
Production and characterization of signal molecules of the “quorum sensing” system in Gram-positive, probiotic bacteria
Probiotics are defined as living microorganisms that, when administered in adequate amounts, exhibit a beneficial effect on the health of the host. They are used in food production e.g. milk products, as well as pills etc. Especially in the last years there was also a growing commercial interest in these products. Although the beneficial effects, e.g. stimulation of the immune system or reducing the development of atopic diseases in childhood, are known, the mechanisms are hardly understood. Therefore, this work should prove the hypothesis, that signal molecules of the “quorum sensing” (QS) system show the ability to stimulate immune reactions. QS is defined as cell density-dependent physiological changes in a bacterial population. This work focuses on the Gram-positive bacteria Lactobacillus, Bacillus and Bifidobacterium. Their QS-active substances will be isolated from cell supernatant and characterized. Afterwards the genome sequence of a chosen bacterial strain, which is producing signal peptides with promising immunological effects, will be analyzed by 454-pyrosequencing to identify the production cluster on genetic basis. Support should be given by transposon mutations. The work will be done in close cooperation with a chemical-analytical and an immunological PhD thesis.
