PMID- 20681521 OWN - NLM STAT- MEDLINE DCOM- 20101220 LR - 20131121 IS - 1520-5851 (Electronic) IS - 0013-936X (Linking) VI - 44 IP - 17 DP - 2010 Sep 1 TI - Monitoring gene expression to evaluate oxygen infusion at a gasoline-contaminated site. PG - 6829-34 LID - 10.1021/es101356t [doi] AB - Increasingly, molecular biological tools, most notably quantitative polymerase chain reaction (qPCR), are being employed to provide a more comprehensive assessment of bioremediation of petroleum hydrocarbons and fuel oxygenates. While qPCR enumeration of key organisms or catabolic genes can aid in site management decisions, evaluation of site activities conducted to stimulate biodegradation would ideally include a direct measure of gene expression to infer activity. In the current study, reverse-transcriptase (RT) qPCR was used to monitor gene expression to evaluate the effectiveness of an oxygen infusion system to promote biodegradation of BTEX and MTBE. During system operation, dissolved oxygen (DO) levels at the infusion points were greater than 30 mg/L, contaminant concentrations decreased, and transcription of two aromatic oxygenase genes and Methylibium petroleiphilum PM1-like 16S rRNA copies increased by as many as 5 orders of magnitude. Moreover, aromatic oxygenase gene transcription and PM1 16s rRNA increased at downgradient locations despite low DO levels even during system operation. Conversely, target gene expression substantially decreased when the system was deactivated. RT-qPCR results also corresponded to increases in benzene and MTBE attenuation rates. Overall, monitoring gene expression complemented traditional groundwater analyses and conclusively demonstrated that the oxygen infusion system promoted BTEX and MTBE biodegradation. FAU - Baldwin, Brett R AU - Baldwin BR AD - Microbial Insights, Inc., Rockford, Tennessee 37853-3044, USA. FAU - Biernacki, Anita AU - Biernacki A FAU - Blair, Joel AU - Blair J FAU - Purchase, Michael P AU - Purchase MP FAU - Baker, Jeffrey M AU - Baker JM FAU - Sublette, Kerry AU - Sublette K FAU - Davis, Greg AU - Davis G FAU - Ogles, Dora AU - Ogles D LA - eng PT - Journal Article PL - United States TA - Environ Sci Technol JT - Environmental science & technology JID - 0213155 RN - 0 (Environmental Pollutants) RN - 0 (Gasoline) RN - 0 (RNA, Messenger) RN - 0 (Xylenes) RN - 3FPU23BG52 (Toluene) RN - J64922108F (Benzene) RN - S88TT14065 (Oxygen) SB - IM MH - Benzene/analysis MH - Biodegradation, Environmental MH - California MH - *Environmental Monitoring MH - Environmental Pollutants/*analysis MH - Gasoline/*analysis MH - *Gene Expression Regulation, Bacterial MH - Kinetics MH - Oxygen/*analysis MH - Proteobacteria/enzymology/*genetics MH - RNA, Messenger/genetics/metabolism MH - Toluene/analysis MH - Xylenes/analysis EDAT- 2010/08/05 06:00 MHDA- 2010/12/21 06:00 CRDT- 2010/08/05 06:00 PHST- 2010/08/05 06:00 [entrez] PHST- 2010/08/05 06:00 [pubmed] PHST- 2010/12/21 06:00 [medline] AID - 10.1021/es101356t [doi] PST - ppublish SO - Environ Sci Technol. 2010 Sep 1;44(17):6829-34. doi: 10.1021/es101356t.