Integration of transcriptomic and proteomic reveals the toxicological molecular mechanisms of decabromodiphenyl ethane (DBDPE) on Pleurotus ostreatus.

Decabromodiphenyl ethane (DBDPE), as one of the most widely used new brominated flame retardants (NBFRs), can pose a potential threat to human health and the environment. An integrated transcriptome and proteome was performed for investigating the toxicological molecular mechanisms of Pleurotus ostreatus (P. ostreatus) during the biodegradation of DBDPE at the concentrations of 5 and 20 mg/L. A total of 1193/1018 and 92/126 differentially expressed genes/proteins (DEGs/DEPs) were found, respectively, with DBDPE exposure at 5 and 20 mg/L. These DEGs and DEPs were mainly involved in the cellular process as well as metabolic process. DEPs for oxidation-reduction process and hydrolase activity were up-regulated, and those for membrane, lipid metabolic process and transmembrane transport were down-regulated. The DEGs and DEPs related to some key enzymes were down-regulated, such as NADH dehydrogenase/oxidoreductase, succinate dehydrogenase, cytochrome C1 protein, cytochrome-c oxidase/reductase and ATP synthase, which indicated that DBDPE affected the oxidative phosphorylation as well as tricarboxylic acid (TCA) cycle. Cytochrome P450 enzymes (CYPs) might be involved in DBDPE degradation through hydroxylation and oxidation. Some stress proteins were induced to resist DBDPE toxicity, including major facilitator superfamily (MFS) transporter, superoxide dismutase (SOD), molecular chaperones, heat shock proteins (HSP20, HSP26, HSP42), 60S ribosomal protein and histone H4. The findings help revealing the toxicological molecular mechanisms of DBDPE on P. ostreatus, aiming to improve the removal of DBDPE.

Toxicity evaluation of decabromodiphenyl ethane (DBDPE) to Pleurotus ostreatus: Oxidative stress, morphology and transcriptomics.

Decabromodiphenyl ethane (DBDPE), one widely used new brominated flame retardant, was of great concern due to its biotoxicity. The toxic evaluation of DBDPE (1-50 mg/L) to white-rot fungus (Pleurotus ostreatus), including oxidative stress, morphology and transcriptomics was conducted aiming at improving its biodegradation. Fungal growth and ATPase activity were obviously inhibited by DBDPE at ≥ 10 mg/L with the exposure from 48 h to 96 h. DBDPE could induce oxidative stress to P. ostreatus. The activity of SOD (superoxide dismutase), CAT (catalase) and GSH (glutathione) were all promoted by DBDPE at ≤ 5 mg/L and inhibited at > 5 mg/L with 96-h exposure. MDA (malondialdehyde) content rose obviously with DBDPE exposure (10-50 mg/L). The mycelium was wizened under 20 mg/L DBDPE exposure according to SEM observation. Transcriptomics analysis suggested that DBDPE could change many functional genes expression of P. ostreatus. GO analysis indicated DBDPE could affect biological process and cellular component by inhibiting electron transport, mitochondrial ATP synthesis, oxidoreductase activity as well as transporter activity. KEGG enrichment pathways analysis indicated DBDPE could inhibit oxidative phosphorylation, tricarboxylic acid (TCA) cycle and carbon metabolism by down-regulating the genes related to NADH reductase/dehydrogenase, succinate dehydrogenase, cytochrome-c reductase/oxidase, cytochrome C1 protein and ATP synthase.

Biodegradation of decabromodiphenyl ethane (DBDPE) by white-rot fungus Pleurotus ostreatus: Characteristics, mechanisms, and toxicological response.

Decabromodiphenyl ethane (DBDPE) can pose a potential toxic threat to human beings and the environment. P. ostreatus, as one of the typical white-rot fungi, can effectively degrade various refractory pollutants. The biodegradable characteristics of DBDPE by P. ostreatus, as well as the mechanisms, and toxicological response were investigated in this study. The removal rate reached 47.73% and 43.20%, respectively, for 5 and 20 mg/L DBDPE after 120-h degradation by P. ostreatus. As a coexisting substance, Pb could inhibit the biodegradation. It is found that both the intracellular enzyme (P450) and extracellular enzymes (manganese peroxidase (MnP), lignin peroxidase (LiP), and laccase (Lac)) played a very important role in the biodegradation of DBDPE, of which Lac dominated the degradation. The toxic response was monitored during the degradation. The activities of SOD and CAT were enhanced to eliminate excess ROS in P. ostreatus triggered by DBDPE. In addition, debromination, hydroxylation, and oxidation were inferred as the main degradation pathways preliminarily. The findings provide a theoretical basis for the application of microbial degradation of DBDPE contamination.