Oligo(cis-1,4-isoprene) aldehyde-oxidizing dehydrogenases of the rubber-degrading bacterium Gordonia polyisoprenivorans VH2.

The actinomycete Gordonia polyisoprenivorans strain VH2 is well-known for its ability to efficiently degrade and catabolize natural rubber [poly(cis-1,4-isoprene)]. Recently, a pathway for the catabolism of rubber by strain VH2 was postulated based on genomic data and the analysis of mutants (Hiessl et al. in Appl Environ Microbiol 78:2874-2887, 2012). To further elucidate the degradation pathway of poly(cis-1,4-isoprene), 2-dimensional-polyacrylamide gel electrophoresis was performed. The analysis of the identified protein spots by matrix-assisted laser desorption/ionization-time of flight tandem mass spectrometry confirmed the postulated intracellular pathway suggesting a degradation of rubber via ß-oxidation. In addition, other valuable information on rubber catabolism of G. polyisoprenivorans strain VH2 (e.g. oxidative stress response) was provided. Identified proteins, which were more abundant in cells grown with rubber than in cells grown with propionate, implied a putative long-chain acyl-CoA-dehydrogenase, a 3-ketoacyl-CoA-thiolase, and an aldehyde dehydrogenase. The amino acid sequence of the latter showed a high similarity towards geranial dehydrogenases. The expression of the corresponding gene was upregulated > 10-fold under poly(cis-1,4-isoprene)-degrading conditions. The putative geranial dehydrogenase and a homolog were purified and used for enzyme assays. Deletion mutants for five aldehyde dehydrogenases were generated, and growth with poly(cis-1,4-isoprene) was investigated. While none of the mutants had an altered phenotype regarding growth with poly(cis-1,4-isoprene) as sole carbon and energy source, purified aldehyde dehydrogenases were able to catalyze the oxidation of oligoisoprene aldehydes indicating an involvement in rubber degradation.

Expression of HPV, steroid receptors (ERalpha, ERbeta, PR-A and PR-B) and inhibin/activin subunits (alpha, betaA and betaB) in adenosquamous endometrial carcinoma.

AIM: The aim of the study was to determine possible pathogenetic factors and molecules which may be used as tumor markers of adenosquamous endometrial carcinoma. MATERIALS AND METHODS: Eight adenosquamous endometrial carcinomas were immunohistochemically tested with specific monoclonal antibodies for HPV (polyclonal anti-HPV and monoclonal anti-HPV 18), estrogen receptors ER-alpha and ER-beta, progesterone receptors PR-A and PR-B and the inhibin/activin subunits inhibin-alpha, -betaA and -betaB. RESULTS: HPV 18 and the polyclonal HPV antibody was detected in all adenosquamous endometrial carcinomas, both in the endometrioid (n = 7/8) and squamous (n = 8/8) parts of the tumor. Neither ER-alpha or ER-beta were detectable in any tumor, in contrast to PR-A and PR-B which were detected in about half of these tumors (PR-A: n = 5/8 and PR-B: n = 2/8). Inhibin-alpha and -betaB were not detected, while inhibin-betaA was expressed in all adenosquamous carcinomas. CONCLUSION: The carcinogenesis of adenosquamous endometrial carcinomas was associated with HPV infection. Adenosquamous endometrial carcinomas seem not to be controlled by estrogens. The absence of the expression of the inhibin-alpha subunit suggests a tumor-suppressive function in adenosquamous endometrial tumors. The absence of the expression of the inhibin-betaB subunit, which is probably a marker of differentiation, points to the malignancy of these tumors. The other inhibin subunit, inhibin-betaA, was expressed in all adenosquamous tumors. It remains to be clarified if these parameters can be used as tumor markers.