A Review on Bacterial Degradation of Benzo[a]pyrene and Its Impact on Environmental Health

Benzo[a]pyrene is a polycyclic aromatic hydrocarbon (PAH) having a high molecular weight. Benzo[a]pyrene and other PAHs are induces severe acute or chronic human health hazards and are extremely carcinogenic, mutagenic, immunotoxic, and teratogenic. Microorganisms play a crucial part in the degradation of benzo[a]pyrene from polluted environments. Such micro-organisms synthesize monooxygenase and di-oxygenase enzymes that proceed with the aerobic or anaerobic catabolic degradations of benzo[a]pyrene. Bioaugmentation, biomineralization, and biostimulation methods can be used for the decontamination of benzo[a]pyrene from hydrocarbon contaminated sites. In this review paper, we thoroughly explained the impacts of benzo[a]pyrene pollution on human health and the environment. Further, this study also described various pathways regarding the bio-degradation of benzo[a]pyrene and also an updated overview of future prospects of benzo[a]pyrene biodegradation

Identification of Damaged DNA Adducts from Exposure to Benzo[a]pyrene in the TP53 Gene

Benzo[a]pyrene is a carcinogen associated with tobacco smoke that can damage DNA after it is metabolized into highly reactive forms. Identifying the resulting DNA adducts can give greater insight into the mutations that frequently occur in lung cancer. This research aimed to identify damaged DNA adducts from exposure to benzo[a]pyrene in the TP53 gene. This gene codes for the p53 protein, which is frequently mutated in cancers. The oligomeric DNA sequence was exposed to myoglobin, benzo[a]pyrene, and hydrogen peroxide. Myoglobin acted as an heme enzyme mimic, and provided similar chemistry to bio-relevant cytochrome P450 enzymes that are involved in the metabolism of substances like benzo[a]pyrene. LC-MS was used to identify DNA adducts.Undergraduate Research and Creativity AwardB.S

Tumour-initiating activities on mouse skin of dihydrodiols derived from benzo[a]pyrene.

Three dihydrodiols that are metabolites of benzo[a]pyrene and benzo[a]-pyrene itself have been tested in a comparative experiment for their activities as initiators of tumours in mouse skin. A single application (25 mug) of 4,5-dihydro-4,5-dihydroxybenzo[a]pyrene, of 7,8-dihydro-7,8-dihydroxybenzo[a]pyrene, of 9,10-dihydro-9,10-dihydroxybenzo[a]pyrene, or of benzo[a]pyrene was made to the shaved dorsal skin of adult female CDI mice; this was followed 2 weeks later by multiple thrice-or twice-weekly applications (1 mug) of 12-O-tetradecanoyl-phorbol-13-acetate as promoting agent. A control group of 30 mice received the promoting agent alone. The experiments were terminated 52 weeks after initiation. At this stage, all the groups contained mice bearing skin papillomas, some of which had progressed to malignancy. Quantitatively the results show that the 7,8-dihydrodiol is almost as active an initiator of mouse skin tumours as benzo[a]pyrene itself; the 4,5- and 9,10-dihydrodiols were significantly less active. The significance of these results is discussed in relation to the hypothesis that diol-epoxides are important in the metabolic activation of polycyclic hydrocarbons like benzo[a]pyrene

Determination of benzo[alpha]pyrene in Turkish döner kebab samples cooked with charcoal or gas fire

peer-reviewedIn order to investigate the levels of the potent carcinogen benzo[a]pyrene (B(a)P), 40 samples of döner kebab were analysed. The samples tested included 20 cooked using a charcoal fire and 20 cooked using a gas fire. A liquid chromatographic method was developed using a fluorescence detector. The mean levels of B(a)P were found to be 24.2 (s.e. 0.84) g/kg for charcoal fire cooked meat samples and 5.7 (s.e. 3.48 g/kg) for gas fire cooked meat samples. Sixteen samples were found to be over the maximum level recommended by FAO/WHO (10 g/kg) and all of the samples exceeded the maximum tolerance level of the Turkish Food Codex (1 g/kg)

Benzo[a]pyrene-induced DNA adducts and gene expression profiles in target and non-target organs for carcinogenesis in mice

Background: Gene expression changes induced by carcinogens may identify differences in molecular function between target and non-target organs. Target organs for benzo[a]pyrene (BaP) carcinogenicity in mice (lung, spleen and forestomach) and three non-target organs (liver, colon and glandular stomach) were investigated for DNA adducts by 32P-postlabelling, for gene expression changes by cDNA microarray and for miRNA expression changes by miRNA microarray after exposure of animals to BaP. Results: BaP-DNA adduct formation occurred in all six organs at levels that did not distinguish between target and non-target. cDNA microarray analysis showed a variety of genes modulated significantly by BaP in the six organs and the overall gene expression patterns were tissue specific. Gene ontology analysis also revealed that BaP-induced bioactivities were tissue specific; eight genes (Tubb5, Fos, Cdh1, Cyp1a1, Apc, Myc, Ctnnb1 and Cav) showed significant expression difference between three target and three non-target organs. Additionally, several gene expression changes, such as in Trp53 activation and Stat3 activity suggested some similarities in molecular mechanisms in two target organs (lung and spleen), which were not found in the other four organs. Changes in miRNA expression were generally tissue specific, involving, in total, 21/54 miRNAs significantly up- or down-regulated. Conclusions: Altogether, these findings showed that DNA adduct levels and early gene expression changes did not fully distinguish target from non-target organs. However, mechanisms related to early changes in p53, Stat3 and Wnt/β-catenin pathways may play roles in defining BaP organotropism