title: Expression of amoA mRNA in wastewater treatment processes examined by competitive RT-PCR.
abstract: The expression of ammonia monooxygenase encoding mRNA (amoA mRNA) in a wastewater treatment process was analyzed in an attempt to propose an effective target for the monitoring of nitrifying bacteria in engineered systems or natural environments. The quick response (1-2 h) of amoA mRNA transcription to the recovery of ammonia oxidation activity induced by the sudden exposure to ammonia was observed in a short-time batch-mode incubation whereas the amount of amoA DNA did not markedly change during the incubation under any conditions. In the continuous feeding-operation, amoA mRNA level dynamically changed in response to the change in the surrounding environmental conditions and increase in ammonia oxidation rate. Although, amoA mRNA level did not quickly respond to the decrease in ammonia oxidation activity, it decreases over long time scales. These results suggest that the profiles of amoA mRNA expression can be used as an indicator of the ammonia oxidation activity.
authors.affiliation: Department of Chemical Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan. yoshiteruaoi@toki.waseda.jp
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Aoi
authors.forename: Yuko
authors.initials: Y
authors.lastname: Shiramasa
authors.forename: Youske
authors.initials: Y
authors.lastname: Masaki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tsuneda
authors.forename: Akira
authors.initials: A
authors.lastname: Hirata
authors.forename: Atsuhi
authors.initials: A
authors.lastname: Kitayama
authors.forename: Teruyuki
authors.initials: T
authors.lastname: Nagamune
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D007220:Industrial Waste / Q000517:prevention & control; D010088:Oxidoreductases / Q000032:analysis* / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D018508:Water Purification / Q000379:methods*
chemical_list: D007220:Industrial Waste; D012333:RNA, Messenger; D000641:Ammonia; D010088:Oxidoreductases; C045582:ammonia monooxygenase