Characterization of aquatic bacteria and cloning of genes specifying partial degradation of 2,4-dichlorophenoxyacetic acid

Abstract

Water samples from rivers, streams, ponds, and activated sewage were tested for the presence of bacteria which utilize 2,4-dichlorophenoxyacetic acid (2,4-D) as a sole source of carbon. Seventy percent of the attempted enrichments yielded pure cultures of 2,4-D-metabolizing bacteria. All but 1 of the 30 isolates were gram-negative rods, all but 2 were motile, and all were nonfermentative and oxidase and catalase positive. Nine isolates had DNA guanine-plus-cytosine values of 61.1 to 65 mol%. One isolate had a 67 mol% guanine-pluscytosine value. The results suggest that these 2,4-D-metabolizing bacteria belong to the genus Alcaligenes. Fourteen of 23 isolates contained one or more detectable plasmids of about 20, 60, or 100 megadaltons. HindlIl restriction fragment patterns showed these plasmids to be different from each other with one exception. Very similar restriction fragment patterns were revealed with a plasmid isolated from an Alcaligenes eutrophus strain obtained from Australia (pJMP397) and in an Alcaligenes sp. isolated in Oregon (pEML159). These two plasmids were about 56 megadaltons, had the same guanine-plus-cytosine value, were transmissable, and coded for 2,4-D metabolism and resistance to HgCI2. Hybridization of these two plasmids was demonstrated by using nick-translated 32P-labeled pJMP397. The vector pBR325 was used to clone Hindlll fragments from pEML159. One cloned fragment of 14.8 megadaltons expressed in Escherichia coli the ability to release 14Co2 from 2,4-D labeled in the acetate portion. * Corresponding author. t Technical paper no. 7428, Oregon Agricultural Experiment Station, Corvallis. OR 97331-3804.

Microbial breakdown of halogenated aromatic pesticides and related compounds

“…Several indistinguishable plasmids, which encoded the degradation of 2,4-D and MCPA, were later isolated from strains of A. paradoxus and A. eutrophus [158,370]. Plasmids encoding the degradation of 2,4-D have been found in numerous other bacteria as well [159,161,162]. One strain, A. eutrophus JMP 134, which harbors the plasmid pJP4, has been used extensively in studying the pathways and genetic regulation of metabolism of halogenated aromatic compounds.…”

Protein production during heat stress and exposure to toxicants in alcaligenes eutrophus JMP228

“…Partial degradative pathways have been identified on plasmids from several bacteria, for example, 2,4-dichlorophenoxy acetic acid mineralization can be accomplished by JMP228 transformed with a plasmid from an Alcaligenes sp. isolated from sewage sludge (Amy et al, 1985). Plasmids such as this have been used to genetically engineer Pseudomonas cepacia AC1100, currently the only bacterium known t o efficiently degrade 2,4,5-T (Kilbane et al, 1983).…”

Identification and quantitative analysis of degradation products of chlorhexidine with chlorhexidine‐resistant bacteria with three‐dimensional high performance liquid chromatography

“…Although there are some reports of biodegradation of other compounds such as khlorobenzoate (Marks et al. 1984) and 2, 44ichlorophenoxyacetate (Amy et al 1985) there are few reports about the decomposition of this compound. All the organisms concerned with chlorhexidine are the resistant germs separated from activated sludge, so they are much weaker in their extent of tolerance than the resistant strains that we obtained in the clinical field.…”