How high G+C Gram-positive bacteria and in particular bifidobacteria cope with heat stress: protein players and regulators.

The Actinobacteridae group of bacteria includes pathogens, plant commensals, endosymbionts as well as inhabitants of the gastrointestinal tract. For various reasons, these microorganisms represent a growing area of interest with respect to genomics, molecular biology and genetics. This review will discuss the current knowledge on the molecular players that allow actinobacteria to contend with heat stress, with an emphasis on bifidobacteria. We describe the principal molecular chaperones involved in heat stress. Temporal expression of heat-shock genes based on functional genomics in members of the Actinobacteridae group is also discussed, as well as the emerging molecular mechanisms controlling the heat-stress response.