Perception and Transduction of Low Temperature in Bacteria

This chapter focuses on the various mechanisms by which membrane fluidity is modulated in bacteria vis-à-vis its importance in cold adaptation. A detailed update on the perception and transduction of low-temperature signals in bacteria is also included. Subsequently, it was found that trans-monounsaturated are predominant in gram-negative bacteria and are synthesized by direct isomerization of cis-unsaturated fatty acids to trans-unsaturated fatty acids without shifting of a double bond. One of the predominant signal transduction mechanisms employed by bacteria is the phosphotransfer pathway commonly referred to as the two-component signal transduction system, which consists of a sensor kinase (histidine kinase) and a response regulator, found in bacteria, Archaea, and Eukarya. The first direct evidence for the two-component signal transduction mechanism involved in sensing cold has come from studies on Bacillus subtilis. Modulation in membrane fluidity appears to be crucial for low-temperature sensing in bacteria, and this is normally achieved by the conversion of saturated fatty acids to unsaturated fatty acids. Yet we are far from understanding many key aspects of bacterial signal transduction in response to low temperature.