Histidine utilisation operon (hut) is upregulated at low temperature in the antarctic psychrotrophic bacterium Pseudomonas syringae

• Published in: FEMS Microbiology Letters
• Main Authors: Kannan, K, Janiyani, Kamala L, Shivaji, S, Ray, M.K
• Format: Text
• Language: English
• Published: Oxford University Press 1998
• Subjects: Articles; Antarctic; The Antarctic; Antarc*
• Online Access: http://femsle.oxfordjournals.org/cgi/content/short/161/1/7; https://doi.org/10.1111/j.1574-6968.1998.tb12922.x

The antarctic psychrotrophic bacterium Pseudomonas syringae was mutagenised using a transposon Tn 5 -OT182 which facilitates identification of promoter fusions expressing the reporter gene ( lacZ ) for β-galactosidase. Most mutants expressed β-galactosidase both at optimal growth temperature (20–22°C) and at low temperature (4°C). But a small percentage of the mutants (∼5%) were unique in that they expressed β-galactosidase activity predominantly at low temperature. One such mutant was found to have an insertion in the gene for urocanase ( hutU ) of the histidine utilisation ( hut ) operon. Direct assay of urocanase and histidase activity in wild-type cells of various antarctic psychrotrophic strains including P. syringae, P. fluorescens and P. putida also suggested that the hut operon is expressed at an elevated level at low temperature.