Enzymatic and genetic profiles in environmental strains grown on polycyclic aromatic hydrocarbons

Abstract

The possible generation of oxidative stress induced by aromatic hydrocarbon degradation suggests that ancillary enzyme activities could facilitate the utilization of polycyclic aromatic hydrocarbons as sole carbon source. To investigate the metabolic profiles of low molecular weight polycyclic aromatic hydrocarbon-degrading strains of Sphingobium chlorophenolicum, Rhodococcus aetherovorans, Rhodococcus opacus and Mycobacterium smegmatis, the determination of the activity of putative detoxifying enzymes (rhodanese-like and glutathione S-transferase proteins) was combined with genetic analyses. All the studied strains were able to utilize phenanthrene or naphthalene. Glutathione S-transferase activity was found in S. chlorophenolicum strains grown on phenanthrene and it was related to the presence of the bphK gene, since modulation of glutathione S-transferase activity by phenanthrene paralleled the induction of glutathione S-transferase transcript in the S. chlorophenolicum strains. No glutathione S-transferase activity was detectable in R. aetherovorans, R. opacus and in M. smegmatis strains. All strains showed 3-mercaptopyruvate:cyanide sulfurtransferase activity. A rhodanese-like SseA protein was immunodetected in R. aetherovorans, R. opacus and in M. smegmatis strains, where increase of 3-mercaptopyruvate:cyanide sulfurtransferase activity was significantly induced by growth on phenanthrene.

Bacterial Diversity and Bioremediation Potential of the Highly Contaminated Marine Sediments at El-Max District (Egypt, Mediterranean Sea)

“…Primers dacr5F (5′-TGATCTGGGTCATGATCTTCCCVATGMTGVT-3′) and dacr4R (5′-CGGCCACGGCCAGYTCRAARAARTT-3′) were used for amplification of arsenite efflux pump ( ACR3(2) ) according to Achour et al [ 13 ]. Primers Phn321F (5′-TTCTCGGTCGGG ACTTTCCAA-3′) and Phn671R (5′-GGCAACCAGATCTGTCATG-3′) were used for amplification of phnA1 gene coding for 3,4-phenanthrene dioxygenase, according to Cavalca et al [ 14 ]. PCR reactions were performed in a final volume of 25 μ L containing 1X buffer, 1.75 mM MgCl 2 , 0.2 mM of dNTPs mixture, 0.4 μ M of each primer, 1.5 U Taq polymerase, and 10 ng of total DNA.…”

Glutathione transferases in bacteria

“…Bacterial GSTs are also involved in the degradation of several monocyclic aromatic compounds such as toluene, xylenes, phenols and atrazine [72]. They also take part in the degradation of polycyclic aromatic hydrocarbons, a class of hazardous chemicals to both environmental and human health [21,[73][74][75][76][77][78].…”

Effects of the deficiency of the rhodanese‐like protein RhdA in Azotobacter vinelandii

“…In order to corroborate the reproducibility of the results, at least three extractions were made for each strain, and three gels were run for each sample. Immunological detection of RhdA protein blotted from 2-DE gels on to nitrocellulose membranes was performed as previously described [13], by using selective anti-RhdA antibodies [16].…”

“…identification of selected protein spots The availability of anti-RhdA antibodies that did not show cross-reactions with other two-domains rhodanese-like proteins [16] allowed the identification of A. vinelandii MV474 as a null RhdA strain. Western blot analysis clearly showed that no protein corresponding to RhdA was expressed in this mutant (see enlargement of Fig.…”