Evolutionary trade-off between heat shock resistance, growth at high temperature, and virulence expression in Typhimurium.

Unlabelled: Understanding the evolutionary dynamics of foodborne pathogens throughout our food production chain is of utmost importance. In this study, we reveal that Typhimurium can readily and reproducibly acquire vastly increased heat shock resistance upon repeated exposure to heat shock. Counterintuitively, this boost in heat shock resistance was invariantly acquired through loss-of-function mutations in the gene, encoding a heat shock protein that acts as a molecular co-chaperone of DnaK and enables its role in protein folding and disaggregation.

Phylogenomic analysis of the genus and description of sp. nov., sp. nov., subsp. subsp. nov., subsp. subsp. nov., subsp. subsp. nov., subsp. subsp. nov. and subsp. subsp. nov., isolated from floral nectar and insects.

The genus is one of the most frequent bacterial inhabitants of flowers and a usual member of the insect microbiota worldwide. To date, there is only one publicly available genome, corresponding to the type strain of (8N4), which precludes a detailed analysis of intra-genus phylogenetic relationships. In this study, we obtained draft genomes of the type strains of the other species validly published to date (, and ) and 23 additional isolates of flower and insect origin.

Selection and Development of Nontoxic Nonproteolytic Surrogate Strains for Food Challenge Testing.

causes severe foodborne intoxications by producing a potent neurotoxin. Challenge studies with this pathogen are an important tool to ensure the safety of new processing techniques and newly designed or modified foods, but they are hazardous and complicated by the lack of an effective selective counting medium. Therefore, this study aimed to develop selectable nontoxic surrogate strains for group II, or nonproteolytic, , which are psychotropic and hence of particular concern in mildly treated, refrigerated foods.

High-Throughput Time-Lapse Fluorescence Microscopy Screening for Heterogeneously Expressed Genes in Bacillus subtilis.

Elucidating phenotypic heterogeneity in clonal bacterial populations is important for both the fundamental understanding of bacterial behavior and the synthetic engineering of bacteria in biotechnology. In this study, we present and validate a high-throughput and high-resolution time-lapse fluorescence microscopy-based strategy to easily and systematically screen for heterogeneously expressed genes in the Bacillus subtilis model bacterium. This screen allows detection of expression patterns at high spatial and temporal resolution, which often escape detection by other approaches, and can readily be extrapolated to other bacteria.