Molecular process of regulation and expression of candidate genes involved in prebiotic fibre utilization in Lactobacillus plantarum

Background:

Probiotics are live microorganisms that when administered in adequate amounts confer a health benefit to the consumer. Prebiotics are non-digestible food ingredients, usually fibres, that beneficially affect the host’s health through selective stimulation of growth and/or activity of various non-pathogenic microorganisms present in the host gastrointestinal (GI) tract. The concept of “synbiotics”, introduced in 1995, was defined as “mixtures of probiotics and prebiotics that beneficially affect the host by improving the survival and colonization of live microbial dietary supplements in the GI tract, by selectively stimulating the growth and/or by activating the metabolism of one or a limited number of health-promoting bacteria, thus improving host welfare (Gibson & Roberfroid, J Nutr, 1995 125:1401-1412). However, in a synbiotic concept the prebiotic compound may not necessarily elicit a health benefit by exclusively modulating the endogenous microbiome, but may also achieve this by enhancing the viability and activity of the administered probiotic. Beneficial effects of probiotics can be limited when the intestinal delivery of live bacteria is insufficient or too short-lived to elicit the required responses in the intestinal mucosa. Prebiotics could provide a substrate for growth of probiotics in situ while residing in the GI tract, and thereby increase and/or extend the abundance and persistence of these health-promoting bacteria, to enhance their capacity to elicit their health promoting effects.

Objectives:

The motivation in this research lies in the potential to optimize the delivery of a commonly marketed probiotic, Lactobacillus plantarum, in the host through the simultaneous administration of prebiotic fibres that would actively increase the activity and/or growth of the probiotic. To this end, candidate synbiotic concepts have been evaluated in the context of the dietary regime in which they are administered in rats. However, to better understand the mechanisms of prebiotic fibre utilisation by L. plantarum in the gastro-intestinal tract, the molecular processes and regulation of candidate genes involved in fibre utilisation need to be explored.

Methodology:

This project covers diverse aspects of microbiology and molecular biology as well as carbohydrate chemistry. Techniques that are involved in this project include:

-       Bacterial cultivation

-       Genetic analysis of microorganisms

-       Molecular cloning

-       PCR

-       SDS-Page

-       Proteomics

-       HPAEC-PAD

Requirements:

-       The student should be following a MSc programme in biology, biotechnology, molecular life sciences or a similar study with a background in either: microbiology or molecular biology.

-       Basic experience with molecular cloning techniques

Contact information:

Jori Fuhren has the opportunity to take up new students in March 2019
jori.fuhren@wur.nl