Open AccessHistidine utilisation operon ( hut ) is upregulated at low temperature in the antarctic psychrotrophic bacterium Pseudomonas syringae
Author(s) -
Kannan K,
Janiyani Kamala L,
Shivaji S,
Ray M.K
Publication year - 1998
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1998.tb12922.x
Subject(s) - pseudomonas syringae , operon , mutant , biology , pseudomonadales , pseudomonas putida , pseudomonas , pseudomonas fluorescens , psychrotrophic bacteria , pseudomonadaceae , bacteria , microbiology and biotechnology , gene , biochemistry , genetics
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.