Protective Cultures in Food Products: From Science to Market.

An ultimate goal in food production is to guarantee food safety and security. Fermented food products benefit from the intrinsic capabilities of the applied starter cultures as they produce organic acids and bactericidal compounds such as hydrogen peroxide that hamper most food pathogens. In addition, highly potent small peptides, bacteriocins, are being expelled to exert antibiotic effects.

Multiple allosteric effectors control the affinity of DasR for its target sites.

The global transcriptional regulator DasR connects N-acetylglucosamine (GlcNAc) utilization to the onset of morphological and chemical differentiation in the model actinomycete Streptomyces coelicolor. Previous work revealed that glucosamine-6-phosphate (GlcN-6P) acts as an allosteric effector which disables binding by DasR to its operator sites (called dre, for DasR responsive element) and allows derepression of DasR-controlled/GlcNAc-dependent genes. To unveil the mechanism by which DasR controls S.

Genome-wide analysis of in vivo binding of the master regulator DasR in Streptomyces coelicolor identifies novel non-canonical targets.

Streptomycetes produce a wealth of natural products, including over half of all known antibiotics. It was previously demonstrated that N-acetylglucosamine and secondary metabolism are closely entwined in streptomycetes. Here we show that DNA recognition by the N-acetylglucosamine-responsive regulator DasR is growth-phase dependent, and that DasR can bind to sites in the S.

Nitrogen starvation-induced transcriptome alterations and influence of transcription regulator mutants in Mycobacterium smegmatis.

Background: As other bacteria, Mycobacterium smegmatis needs adaption mechanisms to cope with changing nitrogen sources and to survive situations of nitrogen starvation. In the study presented here, transcriptome analyses were used to characterize the response of the bacterium to nitrogen starvation and to elucidate the role of specific transcriptional regulators.

Results: In response to nitrogen deprivation, a general starvation response is induced in M.

Regulon of the N-acetylglucosamine utilization regulator NagR in Bacillus subtilis.

N-Acetylglucosamine (GlcNAc) is the most abundant carbon-nitrogen biocompound on earth and has been shown to be an important source of nutrients for both catabolic and anabolic purposes in Bacillus species. In this work we show that the GntR family regulator YvoA of Bacillus subtilis serves as a negative transcriptional regulator of GlcNAc catabolism gene expression. YvoA represses transcription by binding a 16-bp sequence upstream of nagP encoding the GlcNAc-specific EIIBC component of the sugar phosphotransferase system involved in GlcNAc transport and phosphorylation, as well as another very similar 16-bp sequence upstream of the nagAB-yvoA locus, wherein nagA codes for N-acetylglucosamine-6-phosphate deacetylase and nagB codes for the glucosamine-6-phosphate (GlcN-6-P) deaminase.