title: Distribution and effects of 2,4,5-trichlorophenoxyacetic acid in cells of Bacillus megaterium.
abstract: Cell death in a resting population of an asporogenous Bacillus megaterium was accelerated by ambient concentrations of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) equal to or greater than 10 mug/ml or 5 mug/mg of cells (dry weight), but only after prolonged exposure. Conversely, populations of growing cells were not markedly influenced even at 100 mug/ml. Effects on cell respiration were not manifest until the ambient concentration reached 1,000 mug of 2,4,5-T/ml, or 500 mug/mg. Cells of B. megaterium did, however, accumulate 2,4,5-T passively to a level approximately twofold above the ambient concentration. Most of the accumulated compound was easily washed from the cells, but, of the firmly bound herbicide, about 0.5 mug/mg of cells (dry weight), nearly 60% by weight, was localized in the protoplast membrane. The foregoing results, obtained with a purified preparation of 2,4,5-T were also elicited by 2,4,5-T analytical standards. The extracted contaminants did not produce the results alone nor did they influence the results when present in combination with 2,4,5-T.
mesh_terms: D015085:2,4,5-Trichlorophenoxyacetic Acid / Q000378:metabolism / Q000494:pharmacology*; D001410:Bacillus megaterium / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D011523:Protoplasts / Q000378:metabolism
chemical_list: D015085:2,4,5-Trichlorophenoxyacetic Acid