Location and Consequences of 1,1,1-Trichloro-2,2-bis(p-Chlorophenyl) Ethane Uptake by Bacillus megaterium

Abstract

No detrimental effects of 1,1, 1-trichloro-2, 2-bis(p-chlorophenyl)ethane (DDT) were observed when cells of Bacillus megaterium were grown from small inocula in nutrient media containing up to 100 Mg of DDT/ml. However, when the ratio of DDT to biomass of resting cells was held constant, levels of DDT as low as 1 Mg/ml (0.5 Mg/mg of cell dry weight) enhanced the rate of death in the population. The lethal action of DDT was both time-and dose-dependent so that higher doses required less time to effect the same killing than did lower doses. Intact cells bound a maximum of about 1.7 gg of DDT/mg of cell dry weight, of which about 75% was localized in the protoplast membrane. Much of the bound DDT was subsequently lost to the suspending medium and the aqueous stability of the returned DDT was enhanced, possibly by association with solubilized cell materials. A small quantity of bound DDT was converted to 1, 1-dichloro-2, 2-bis(p-chlorophenyl)ethane, which was released from cells somewhat faster than DDT. Apparently the lethal action of DDT was related to its binding in the membrane, but respiration was not inhibited. The atypical macroscopic appearance of membranes isolated from treated cells suggested that cell death may result from altered membrane chemistry.

Taxonomy of the bacterial strain bna5 isolated from ddt contaminated soil by analysing the nucleotide sequence of the 16s-rRNA gene

“…Hichs vµ Corner (1972) ® chøng minh chñng Bacillus megaterium cã kh ¶ n¨ng ph©n hñy DDT [3], do vËy suy ra chñng Bacillus sp.…”

Distribution and effects of 2,4,5-trichlorophenoxyacetic acid in cells of Bacillus megaterium.

“…Growth conditions. Cells of B. megaterium, asporogenous strain KM, were grown in a 2% peptone medium and harvested as described previously (5). In experiments involving 2,4,5-T exposure, the medium was made 0.01 M in potassium phosphate buffer by the addition of appropriately diluted stock herbicide preparations.…”

Products Formed from Analogues of 1,1,1-Trichloro-2,2-Bis( p -Chlorophenyl) Ethane (DDT) Metabolites by Pseudomonas putida

“…Microorganisms capable of utilizing 1,1,1trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) as sole source of carbon have yet to be isolated. However, various species convert DDT to 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane, 1,1dichloro-2,2-bis(p-chlorophenyl)ethylene, and p,p'-dichlorobenzophenone (DBP) (7,9,18). The further metabolism of DBP has not yet been observed, and DBP seems to be resistant to microbial degradation (5,8).…”