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 ,ug/ml or 5 ,ug/mg of cells (dry weight), but only after prolonged exposure. Conversely, populations of growing cells were not markedly influenced even at 100 gg/ml. Effects on cell respiration were not manifest until the ambient concentration reached 1,000 ,ug of 2,4,5-T/ml, or 500 pg/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 ,ug/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.

Herbicide Effects on Leaf Litter Decomposition Processes in An Oak‐Hickory Forest

“…ppm) (Bollen 1961). A concentration of 1000 ppm 2, 4, 5-T was required to reduce metabolism in Bacillus megaterium (Hicks and Corner 1975). In addition, herbicides generally have no direct effects on the soil fauna (Wallwork 1970, Edwards 1970.…”