Hoffmann, RF,McLernon, S,Feeney, A,Hill, C,Sleator, RD

2013

November

Bioengineered

A single point mutation in the listerial betL sigma(A)-dependent promoter leads to improved osmo- and chill-tolerance and a morphological shift at elevated osmolarity

Validated

()

Listeria osmotolerance chill-tolerance salt stress twisted cells DEPENDENT TRANSPORT-SYSTEM ESCHERICHIA-COLI GLYCINE BETAINE BACILLUS-SUBTILIS SALT TOLERANCE GENE-EXPRESSION SALMONELLA-TYPHIMURIUM MONOCYTOGENES LO28 MURINE INFECTION BACTERIAL STRESS

4

401

407

Betaine uptake in Listeria monocytogenes is mediated by three independent transport systems, the simplest of which in genetic terms is the secondary transporter BetL. Using a random mutagenesis approach, based on the E. coli XL1 Red mutator strain, we identified a single point mutation in a putative promoter region upstream of the BetL coding region which leads to a significant increase in betL transcript levels under osmo- and chill-stress conditions and a concomitant increase in stress tolerance. Furthermore, the mutation appears to counter the heretofore unreported "twisted" cell morphology observed for L. monocytogenes grown at elevated osmolarities in tryptone soy broth.

10.4161/bioe.24094