Possible involvement of an extracellular superoxide dismutase (SodA) as a radical scavenger in poly(cis-1,4-isoprene) degradation.

Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Correnstrasse 3, D-48149 Münster, Germany.
Applied and Environmental Microbiology (Impact Factor: 3.95). 11/2008; 74(24):7643-53. DOI: 10.1128/AEM.01490-08
Source: PubMed

ABSTRACT Gordonia westfalica Kb1 and Gordonia polyisoprenivorans VH2 induce the formation of an extracellular superoxide dismutase (SOD) during poly(cis-1,4-isoprene) degradation. To investigate the function of this enzyme in G. polyisoprenivorans VH2, the sodA gene was disrupted. The mutants exhibited reduced growth in liquid mineral salt media containing poly(cis-1,4-isoprene) as the sole carbon and energy source, and no SOD activity was detectable in the supernatants of the cultures. Growth experiments revealed that SodA activity is required for optimal growth on poly(cis-1,4-isoprene), whereas this enzyme has no effect on aerobic growth in the presence of water-soluble substrates like succinate, acetate, and propionate. This was detected by activity staining, and proof of expression was by antibody detection of SOD. When SodA from G. westfalica Kb1 was heterologously expressed in the sodA sodB double mutant Escherichia coli QC779, the recombinant mutant exhibited increased resistance to paraquat, thereby indicating the functionality of the G. westfalica Kb1 SodA and indirectly protection of G. westfalica cells by SodA from oxidative damage. Both sodA from G. polyisoprenivorans VH2 and sodA from G. westfalica Kb1 coded for polypeptides comprising 209 amino acids and having approximately 90% and 70% identical amino acids, respectively, to the SodA from Mycobacterium smegmatis strain MC(2) 155 and Micrococcus luteus NCTC 2665. As revealed by activity staining experiments with the wild type and the disruption mutant of G. polyisoprenivorans, this bacterium harbors only one active SOD belonging to the manganese family. The N-terminal sequences of the extracellular SodA proteins of both Gordonia species showed no evidence of leader peptides for the mature proteins, like the intracellular SodA protein of G. polyisoprenivorans VH2, which was purified under native conditions from the cells. In G. westfalica Kb1 and G. polyisoprenivorans VH2, SodA probably provides protection against reactive oxygen intermediates which occur during degradation of poly(cis-1,4-isoprene).

  • [Show abstract] [Hide abstract]
    ABSTRACT: Natural rubber is used for the production of adhesives, latex gloves, tubing and tires. This widespread use is accompanied with an extensive generation of waste rubber material. In many parts of the world, especially industrialized countries, this has prompted legislation to be passed to govern the proper disposal of rubber waste. Even so, the recycling of this polymer is not widely practiced. This review looks at the useful bacteria capable of degrading this recalcitrant polymer. Furthermore we review the mechanism of action and the identification of rubber degrading genes. Clearly, a deep understanding of this biodegradative process at the biochemical and genetic level exists and should prompt the instigation of this knowledge in biotechnological applications.
    Journal of Polymers and the Environment 09/2013; · 1.63 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Superoxide dismutases (SODs) form the foremost line of defense against ROS in aerobes. Pennisetum glaucum cDNA library is constructed to isolate superoxide dismutase cDNA clone (PgCuZnSOD) of 798 bp comprising 5'UTR (111 bp), an ORF (459 bp) and 3'UTR (228 bp). Deduced protein of 152 amino acids (16.7 kDa) with an estimated isoelectric point of 5.76 shared highest homology to cytoplasmic CuZnSODs from monocots i.e., maize, rice. Predicted 3D model reveals a conserved eight-stranded ß-barrel with active site held between barrel and two surface loops. Purified recombinant protein is relatively thermo-stable with maximal activity at pH 7.6 and shows inhibition with H(2)O(2) (4.3 mM) but not with azide (10 mM). In Pennisetum seedlings, abiotic stress induced PgCuZnSOD transcript up-regulation directly correlates to high protein and activity induction. Overexpression of PgCuZnSOD confers comparatively enhanced tolerance to methyl viologen (MV) induced oxidative stress in bacteria. Results imply that PgCuZnSOD plays a functional role in conferring oxidative stress tolerance to prokaryotic system and may hold significant potential to impart oxidative stress tolerance in higher plants through transgenic approach.
    Gene 06/2012; 505(2):309-17. · 2.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Curvularia lunata is an important pathogen causing Curvularia leaf spot in maize. Significant pathogenic variation has been found in Curvularia lunata. To better understand the mechanism of this phenomenon, we consecutively put the selective pressures of resistant maize population on Curvularia lunata strain WS18 (low virulence) artificially. As a result, the virulence of this strain was significantly enhanced. Using 2-DE, 12 up-regulated and 4 down-regulated proteins were identified in virulence-increased strain compared to WS18. Our analysis revealed that melanin synthesis-related proteins (Brn1, Brn2 and SCD) and stress tolerance-related proteins (HSP 70) directly involved in the potential virulence growth as crucial markers or factors in C. lunata. To validate 2-DE results and screen differential genes at mRNA level, we constructed a subtracted cDNA library (Tester: virulence-increased strain; Driver: WS18). A total of 188 unigenes were obtained by this way, of which 14 were indicators for the evolution of pathogen virulence. Brn1 and hsp genes exhibited similar expression patterns corresponding to proteins detected by 2-DE. Overall, our results indicated that differential proteins or genes, being involved with melanin synthesis or tolerance response to stress, could be considered as hallmarks of virulence increase in C. lunata.
    Proteomics 10/2012; · 3.97 Impact Factor

Full-text (2 Sources)

Available from
May 28, 2014