title: Biodegradation of methyl parathion and p-nitrophenol: evidence for the presence of a p-nitrophenol 2-hydroxylase in a Gram-negative Serratia sp. strain DS001.
abstract: A soil bacterium capable of utilizing methyl parathion as sole carbon and energy source was isolated by selective enrichment on minimal medium containing methyl parathion. The strain was identified as belonging to the genus Serratia based on a phylogram constructed using the complete sequence of the 16S rRNA. Serratia sp. strain DS001 utilized methyl parathion, p-nitrophenol, 4-nitrocatechol, and 1,2,4-benzenetriol as sole carbon and energy sources but could not grow using hydroquinone as a source of carbon. p-Nitrophenol and dimethylthiophosphoric acid were found to be the major degradation products of methyl parathion. Growth on p-nitrophenol led to release of stoichiometric amounts of nitrite and to the formation of 4-nitrocatechol and benzenetriol. When these catabolic intermediates of p-nitrophenol were added to resting cells of Serratia sp. strain DS001 oxygen consumption was detected whereas no oxygen consumption was apparent when hydroquinone was added to the resting cells suggesting that it is not part of the p-nitrophenol degradation pathway. Key enzymes involved in degradation of methyl parathion and in conversion of p-nitrophenol to 4-nitrocatechol, namely parathion hydrolase and p-nitrophenol hydroxylase component "A" were detected in the proteomes of the methyl parathion and p-nitrophenol grown cultures, respectively. These studies report for the first time the existence of a p-nitrophenol hydroxylase component "A", typically found in Gram-positive bacteria, in a Gram-negative strain of the genus Serratia.
authors.affiliation: Department of Animal Sciences, University of Hyderabad, Hyderabad, 500 046, India.
authors.forename: Suresh B
authors.initials: SB
authors.lastname: Pakala
authors.forename: Purushotham
authors.initials: P
authors.lastname: Gorla
authors.forename: Aleem Basha
authors.initials: AB
authors.lastname: Pinjari
authors.forename: Ravi Kumar
authors.initials: RK
authors.lastname: Krovidi
authors.forename: Rajasekhar
authors.initials: R
authors.lastname: Baru
authors.forename: Mahesh
authors.initials: M
authors.lastname: Yanamandra
authors.forename: Mike
authors.initials: M
authors.lastname: Merrick
authors.forename: Dayananda
authors.initials: D
authors.lastname: Siddavattam
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D001673:Biodegradation, Environmental; D019392:Cytochrome P-450 CYP2E1 / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D008401:Gas Chromatography-Mass Spectrometry; D008743:Methyl Parathion / Q000737:chemistry / Q000378:metabolism*; D008956:Models, Chemical; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009596:Nitrophenols / Q000737:chemistry / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010802:Phylogeny; D012705:Serratia / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D001426:Bacterial Proteins; D009596:Nitrophenols; D008743:Methyl Parathion; D019392:Cytochrome P-450 CYP2E1; D010100:Oxygen