Many bacterial gene regulatory circuits are controlled by temperature. Temperature-mediated regulation occurs at the level of transcription and translation. Supercoiling, changes in mRNA conformation and protein conformation are all implicated in thermosensing. Bacterial virulence functions are often temperature regulated and thus many an example of thermoregulation comes from pathogenic organisms. H-NS is at the crossroads of regulation in many such systems. mRNA melting has also been shown to act as a thermosensing mechanism in various contexts. Proteins can also act as temperature sensors as exemplified by the gene regulator TlpA in Salmonella typhimurium.