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Title: Factors limiting aliphatic chlorocarbon degradation by Nitrosomonas europaea: Cometabolic inactivation of ammonia monooxygenase and substrate specificity

The soil nitrifying bacterium Nitrosomonas europaea is capable of degrading trichloroethylene (TCE) and other halogenated hydrocarbons. TCE cometabolism by N. europaea resulted in an irreversible loss of TCE biodegradative capacity, ammonia-oxidizing activity, and ammonia-dependent O{sub 2} uptake by the cells. Inactivation was not observed in the presence of allylthiourea, a specific inhibitor of enzyme ammonia monooxygenase, or under anaerobic conditions, indicating that the TCE-mediated inactivation required ammonia monooxygenase activity. When N. europaea cells were incubated with ({sup 14}C)TCE under conditions which allowed turnover of ammonia monooxygenase, a number of cellular proteins were covalently labeled with {sup 14}C. Treatment of cells with allylthiourea or acetylene prior to incubation with ({sup 14}C)TCE prevented incorporation of {sup 14}C into proteins. The ammonia-oxidizing activity of cells inactivated in the presence of TCE could be recovered through a process requiring de novo protein synthesis. In addition to TCE, a series of chlorinated methanes, ethanes, and other ethylenes were screened as substrates for ammonia monooxygenase and for their ability to inactivate the ammonia-oxidizing system of N. europaea. The chlorocarbons would be divided into three classes depending on their biodegradability and inactivating potential: (1) compounds which were not biodegradable by N. europaea and which had no toxicmore » effect on the cells (2) compounds which were cooxidized by N. europaea and had little or no toxic effect on the cells; and (3) compounds which were cooxidized and produced a turnover-dependent inactivation of ammonia oxidation by N. europaea.« less
Authors:
; ;  [1]
  1. (Oregon State Univ., Corvallis (United States))
Publication Date:
OSTI Identifier:
6003453
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied and Environmental Microbiology; (United States); Journal Volume: 57:10
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; CHLORINATED ALIPHATIC HYDROCARBONS; BIODEGRADATION; TOXICITY; AMMONIA; BACTERIA; CARBON 14 COMPOUNDS; ENZYME INHIBITORS; INACTIVATION; METABOLISM; OXYGENASES; SUBSTRATES; TRACER TECHNIQUES; CARBON COMPOUNDS; CHEMICAL REACTIONS; DECOMPOSITION; ENZYMES; HALOGENATED ALIPHATIC HYDROCARBONS; HYDRIDES; HYDROGEN COMPOUNDS; ISOTOPE APPLICATIONS; LABELLED COMPOUNDS; MICROORGANISMS; NITROGEN COMPOUNDS; NITROGEN HYDRIDES; ORGANIC CHLORINE COMPOUNDS; ORGANIC COMPOUNDS; ORGANIC HALOGEN COMPOUNDS; OXIDOREDUCTASES; PROTEINS 540220* -- Environment, Terrestrial-- Chemicals Monitoring & Transport-- (1990-); 560300 -- Chemicals Metabolism & Toxicology