Advertisement

Interactions between populations ofPseudomonas putida leading to the expression of a cryptic dehalogenase gene (dehll)

  • J. H. Slater
  • S. J. Hope
Research

Abstract

In appropriate environments containing 2-monochloropropionic acid (2MCPA), mutations in a population of nondehalogenatingPseudomonas putida, strain PP40-040 (parent population), resulted in the formation of 2mcpa+ papillae as a result of the decryptification of adehII gene. Increasing the size of the parent population, for example by increasing the availability of a metabolizable substrate such as succinate or lactate, increased the number of 2mcpa+ papillae formed because there were more parent cells available for mutation to the 2mcpa+ phenotype. The presence of a dehalogenating population, such asP. putida strain PP3, in close proximity to the non-dehalogenating population, also increased the number of 2mcpa+ papillae formed. This was due to the excretion of dehalogenases into the growth medium, which caused localized dehalogenation of the available 2MCPA, yielding a metabolizable substrate. This substrate stimulated the growth of the non-dehalogenating population, in turn increasing the number of 2mcpa+ papillae formed. Barriers, such as dialysis membranes, which prevented the excretion of the dehalogenases into the growth medium, prevented the stimulation of 2mcpa+ papillae formation by preventing release of metabolizable substrates from 2MCPA breakdown. Cell-free extracts (CFE) from dehalogenase-producing populations had a similar effect for the same reason. CFE without dehalogenase activity or in which the dehalogenase activity had been destroyed by heating failed to stimulate parent population growth and 2mcpa+ papillae formation. In the case ofPseudomonas putida strain PP3, which carries an easily transposed dehalogenase-encoding transposon, treatment of CFE with DNAase eliminated an additional factor involved in the formation of 2mcpa+ papillae.

Key words

Biodegradation cryptic genes dehalogenases papillae Pseudomonas putida 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Hope, S.J. & Slater, J.H. 1995 Cryptic dehalogenase and chloroamidase genes inPseudomonas putida and the influence of environmental conditions on their expression.Archives for Microbiology, in press.Google Scholar
  2. SeniorE., BullA.T. & SlaterJ.H. 1976 Enzyme evolution in a microbial community growing on the herbicide Dalapon.Nature 263, 476–479.Google Scholar
  3. SlaterJ.H. 1994 Microbial dehalogenation of haloaliphatic compounds. InBiochemistry of Microbial Degradation, ed RatledgeC., pp. 379–421. Dordrecht: Kluwer Academic.Google Scholar
  4. SlaterJ.H., LovattD., WeightmanA.J., SeniorE. & BullA.T. 1979 The growth ofPseudomonas putida on chlorinated aliphatic acids and its dehalogenating activity.Journal of General Microbiology 114, 125–136.Google Scholar
  5. SlaterJ.H., WeightmanA.J. & HallB.G. 1985 Dehalogenase genes ofPseudomonas putida PP3 on chromosomally located transposable elements.Molecular Biology and Evolution 2, 557–567.Google Scholar
  6. Thomas, A.W. 1990 Analysis of a mobile genetic element fromPseudomonas putida which encodes dehalogenase functions. PhD Thesis, University of Wales, Cardiff, UK.Google Scholar
  7. ThomasA.W., LewingtonJ., HopeS., ToppingA.W., WeightmanA.J. & SlaterJ.H. 1992c Environmentally directed mutations in the dehalogenase system ofPseudomonas putida strain PP3.Archives for Microbiology 158, 176–182.Google Scholar
  8. ThomasA.W., SlaterJ.H. & WeightmanA.J. 1992a The dehalogenase genedehI fromPseudomonas putida strain PP3 is carried on an unusual mobile genetic element designatedDEH.Journal of Bacteriology 174, 1932–1940.Google Scholar
  9. ThomasA.W., ToppingA.W., SlaterJ.H. & WeightmanA. J. 1992b Localisation and functional analysis of structural and regulatory dehalogenase genes carried onDEH fromPseudomonas putida strain PP3.Journal of Bacteriology 174, 1941–1947.Google Scholar
  10. WeightmanA.J. & SlaterJ.H. 1980 Selection ofPseudomonas putida strains with elevated dehalogenase activity by continuous culture growth on chlorinated alkanoic acids.Journal of General Microbiology 121, 187–193.Google Scholar
  11. WeightmanA.J., WeightmanA.L. & SlaterJ.H. 1985 Toxic effects of chlorinated and brominated alkanoic acids onPseudomonas putida PP3: selection at high frequencies of mutations in gene encoding dehalogenases.Applied and Environmental Microbiology 49, 1494–1501.Google Scholar

Copyright information

© Rapid Communications of Oxford Ltd 1995

Authors and Affiliations

  • J. H. Slater
    • 1
  • S. J. Hope
    • 1
  1. 1.School of Pure and Applied BiologyUniversity of Wales-CardiffCardiffUK

Personalised recommendations