title: A novel pathway for the catabolism of 4-nitrotoluene by Pseudomonas.
abstract: Eleven strains of Pseudomonas were isolated by selective enrichment on 4-nitrotoluene (4NT). They all utilized 4NT, 4-nitrobenzyl alcohol (4NBA) or 4-nitrobenzoate (4NBZate) as sole sources of carbon and nitrogen. One strain, TW3, was used for more detailed studies. 4NT-grown cells of TW3 take up O2 when incubated in the presence of 4NBA, 4-nitrobenzaldehyde (4NBZ) and 4NBZate. HPLC analysis of culture supernatants showed that 4NBZ and 4NBZate were formed when 4NT-grown cells wer incubated with 4NBA, whereas only 4NBZate was found when they were incubated with 4NBZ. Two dehydrogenases were detected in extracts of 4NT-grown cells. 4NBA dehydrogenase could be assayed by a dye-linked assay whereas 4NBZ dehydrogenase activity was linked to NAD+ reduction. No nitrite was detected in supernatants of 4NBZate-grown cells incubated with 4NBZate but the nitrogen appeared as ammonium. The only aromatic ring-cleavage dioxygenase that was induced during growth on the nitroaromatics was protocatechuate 3,4-dioxygenase. It is proposed that the pathway for 4NT catabolism proceeds via 4NBA, 4NBZ and 4NBZate and ultimately to protocatechuate with release of the nitro group as ammonium.
authors.affiliation: School of Biological Sciences, University of Wales, Bangor, Gwynedd, UK.
authors.forename: W
authors.initials: W
authors.lastname: Rhys-Williams
authors.forename: S C
authors.initials: SC
authors.lastname: Taylor
authors.forename: P A
authors.initials: PA
authors.lastname: Williams
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism; D000445:Aldehyde Oxidoreductases / Q000378:metabolism; D001426:Bacterial Proteins; D001711:Biotransformation; D009579:Nitrobenzoates / Q000378:metabolism; D010101:Oxygen Consumption; D011549:Pseudomonas / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D012988:Soil Microbiology; D014050:Toluene / Q000031:analogs & derivatives* / Q000378:metabolism / Q000493:pharmacokinetics
chemical_list: D001426:Bacterial Proteins; D009579:Nitrobenzoates; D014050:Toluene; C017572:4-nitrotoluene; D000429:Alcohol Oxidoreductases; C084444:NtnD protein, Pseudomonas sp. TW3; D000445:Aldehyde Oxidoreductases; C084445:4-nitrobenzaldehyde dehydrogenase; C008629:4-nitrobenzoic acid