Streptomycin‐resistant (rpsL) or rifampicin‐resistant (rpoB) mutation in Pseudomonas putida KH146‐2 confers enhanced tolerance to organic chemicals

Abstract

We found that certain Str-, Gen- or Rif- mutants derived from Pseudomonas putida KH146-2, which are resistant to streptomycin, gentamicin or rifampicin, respectively, are tolerant to the aromatic compound 4-hydroxybenzoate (4HBA). The minimum inhibitory concentration (MIC) of 4HBA as the sole carbon source for the wild-type strain was 1%, whereas the MIC for the mutants was 1.7%. Frequency of 4HBA-tolerant mutants among spontaneous Str-, Gen- and Rif- mutants was 5-15%, 3-5%, and 3% respectively. These 4HBA-tolerant mutants also tolerated to a variety of organic chemicals such as 3-hydroxybenzoate, aliphatic and heterocyclic compounds, chlorobenzoates, as well as organic solvents toluene and m-xylene. The Str mutants had a point mutation in the rpsL gene, which produces the ribosomal protein S12. The Rif mutants were found to have a point mutation in the rpoB gene, which encodes the RNA polymerase beta-subunit. Mutation points in Gen mutants still remain unknown. Str-, Gen- and Rif-phenotypes occurred in spontaneous 4HBA-tolerant mutants which had been selected by successively increasing concentrations (from 0.8% to 5%) of 4HBA. Complementation experiments with one of the Str mutants demonstrated a causal relationship between a rpsL mutation (str-1) and 4HBA tolerance. Uptake experiments using [14C]-4HBA revealed that apparent ability of 4HBA to be taken up by the membrane transport system was reduced two to threefold in the mutants compared to the wild-type strain, accounting at least partly for the enhanced tolerance to 4HBA. Our approaches thus could be effective in improvement of tolerance to aromatic compounds of bacteria applicable for bioremediation.

Industrial Robustness: Understanding the Mechanism of Tolerance for the Populus Hydrolysate-Tolerant Mutant Strain of Clostridium thermocellum

“…Mutations to the sigma factor were able to elicit changes in phenotype which confer tolerance to ethanol, metabolite overproduction, and multiple, simultaneous phenotypes [51]. The rpsL gene (Cthe_2727) produces the ribosomal protein S12 [52] which is part of the 30S ribosomal subunit. Alterations in rpsL are known to confer resistance to the error-inducing antibiotic streptomycin [53].…”

History of Antibiotic Adaptation Influences Microbial Evolutionary Dynamics During Subsequent Treatment

“…Genes encoding transcriptional regulators for multidrug efflux pumps were commonly mutated during evolution to all 3 drugs (mexC, mexR, mexS, nalC, nalD, nfxB, parS) [35]. Ribosomal proteins (rplJ, rplL, rpsL, rplF) [36] and NADH dehydrogenase subunits (nuoB, nuoG, nuoL, and nuoM) [37,38] were frequently mutated during tobramycin evolution. The most Drug sequence influences evolution of resistance commonly mutated gene was fusA1, which encodes elongation factor G and was mutated in 11 different replicate lineages adapted to tobramycin.…”

From Microbial Differentiation to Ribosome Engineering

“…75) str, gen, and rif-phenotypes occurred in spontaneous 4HBA-tolerant mutants, that had been selected by successively increasing 4HBA concentrations, from 0.8 to 5%, suggesting that breeding approaches by traditional mutagenesis often involve mutations in a ribosomal component or RNAP. The ability of […”