Dietary fructo-oligosaccharides and inulin decrease resistance of rats to salmonella: protective role of calcium.

Background: We have shown recently that rapid fermentable fructo-oligosaccharides (FOS) decreased resistance of rats towards salmonella. It is not known whether inulin (which is fermented more gradually) has similar effects or whether buffering nutrients can counteract the adverse effects of rapid fermentation.

Aims: To compare the effects of dietary inulin and FOS on resistance of rats to Salmonella enterica serovar Enteritidis and to determine whether calcium phosphate counteracts the effects of fermentation.

Selection and characterization of conditionally active promoters in Lactobacillus plantarum, using alanine racemase as a promoter probe.

This paper describes the use of the alr gene, encoding alanine racemase, as a promoter-screening tool for the identification of conditional promoters in Lactobacillus plantarum. Random fragments of the L. plantarum WCFS1 genome were cloned upstream of the promoterless alr gene of Lactococcus lactis in a low-copy-number plasmid vector.

Metabolic engineering of lactic acid bacteria: overview of the approaches and results of pathway rerouting involved in food fermentations.

Lactic acid bacteria such as Lactococcus lactis are the microorganisms of choice for performing metabolic engineering in relation to food fermentation. These bacteria are used extensively in food fermentations, they have a simple and therefore controllable metabolism and the molecular genetics of these food bacteria is well-developed. There have been recent successes in metabolic engineering in these lactic acid bacteria, including examples of changes in both primary metabolism (diacetyl and alanine) and secondary metabolism (exopolysaccharides and flavour).

Genetics and engineering of microbial exopolysaccharides for food: approaches for the production of existing and novel polysaccharides.

Microbial exopolysaccharides (EPSs) are used in the food industry for their unique properties as viscosifiers, stabilisers, emulsifiers or gelling agents. In recent years, significant progress in the understanding of the genetics and biochemistry of microbial EPS synthesis by both Gram-negative and Gram-positive bacteria has been made. Biosynthesis pathways have been elucidated, and several of the genes involved have been characterised.