Detoxification Of DDT Research Articles

Bioremediation characteristics, influencing factors of dichlorodiphenyltrichloroethane (DDT) removal by using non-indigenous Paracoccus sp.

The marine bacterium able to consume DDT as the nutrient source was isolated from sea water which was identified as Paracoccus sp. DDT-21 based on 16 S rDNA gene sequence and Gram negative rod, obligate aerobic, non-motile biochemical characteristics. The isolate can degrade over 80% of the DDT, at a concentration of 50 mg/L in MSM in 72 h. Time and pollutant (DDT) dependent growth studies indicated that the isolate Paracoccus sp., DDT-21 significantly degrade the DDT and tolerates under DDT stress up to 50 mg/L. The DDT degradation capability of the strain Paracoccus sp. DDT-21 was found to be 5 ˃ 10 ˃ 15 ˃ 25 ˃ 50 mg/L DDT. The high concentrations (75 and 100 mg/L) of DDT showed significant decrease in DDT degradation. The optimal DDT degradation (∼90.0%) was observed at 6 g/L of yeast extract, 6% of glucose in pH 7.0 at 35 °C with 72 h of incubation as constant. Furthermore, four metabolites were observed by GC-MS analysis such as, DDE, DDD, DDMU, and DDA. The obtained results indicate that the isolate Paracoccus sp. DDT-21 is a promising candidate for the removal and/or detoxification of DDT in the environment.

Impacts of Sub-lethal DDT Exposures on microRNA and Putative Target Transcript Expression in DDT Resistant and Susceptible Drosophila melanogaster Strains.

Ten constitutively differentially expressed miRNAs were previously described between DDT-resistant 91-R and -susceptible control Drosophila melanogaster strains, and among their predicted target genes were those associated with metabolic DDT resistance mechanisms. The present study evaluated the inducibility of miRNA expression and putative downstream regulation of cytochrome P450s in response to DDT exposure in a time-dependent manner in 91-R and the susceptible Canton-S strain. Specifically, RT-qPCR analysis showed that DDT exposures led to the significant down-regulation (repression) of miR-310-3p, miR-311-3p, miR-312-3p, miR-313-3p, and miR-92a-3p levels in Canton-S. This is contrasted with the lack of significant changes in 91-R at most time-points following DDT exposure. The levels of expression among miRNAs exhibited opposite expression patterns compared to their corresponding putative target cytochrome P450s at the same time points after DDT exposure. Collectively, results from this study suggest that miR-310-3p, miR-311-3p, miR-312-3p, miR-313-3p, and miR-92a-3p might have a potential role in the control of DDT detoxification through the post-transcriptional regulation of target cytochrome P450s in Canton-S. Conversely, the lack of significant changes of these same miRNAs in 91-R following DDT-exposure suggests a possible adaptive mutation that removes repressive control mechanisms. These data are important for the understanding impact of adaptive changes in miRNA expression on post-transcriptional regulatory mechanism involved in the evolution of DDT resistance in 91-R.

Efficient DDT and trichlorophenol detoxification using NaBH4 and Devarda alloy

DDT—1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane—is a pesticide that has been widely used to control insects in agriculture. TCP—2,4,6-trichlorophenol—has been used in pesticide formulations as a preservative, disinfectant and antiseptic. Detoxification of DDT and TCP is very difficult due to their stable chemical structure. Here, a mixture of NaBH4 and Devarda alloy was applied for the first time to detoxify DDT and TCP. Results show 94 % dechlorination of DDT at 100 °C and 97 % dechlorination of TCP at 80 °C. The presence of diphenyl ethane suggests the complete dechlorination of DDT. The formation of benzene suggests a strong reduction. The method is efficient, cost-effective and may be applied at the industrial-level.

Glutathione S Transferase Activity in Indian Vectors of Malaria: A Defense Mechanism Against DDT

Glutathione S transferases (GSTs) are multifunctional enzymes involved in detoxification of xenobiotic compounds in majority of the insect groups. Significance of insect GSTs is their elevated level of activity in association with insecticide resistance. This investigation was to explore the metabolic status of GSTs in two Indian DDT-resistant malaria vectors, Anopheles culicifacies and Anopheles annularis, and one DDT-susceptible vector, Anopheles fluviatilis. Malkangiri and Koraput districts of Orissa State, endemic for falciparum malaria and having a long insecticide spraying history, were the study areas. F1 progeny was raised from wild-caught females of the three vectors and used for biochemical assays to detect the GST-mediated DDT resistance mechanism. Results of the enzyme assay showed a significant 3-fold increase in GST activity in DDT-resistant An. annularis compared with its susceptible population. In DDT-resistant An. culicifacies, the median GST activity (71.8 micromol/min/mg) was almost the same as estimated in the DDT-resistant An. annularis (74.6 micromol/ min/mg), suggesting that the GST activity estimated in An. culicifacies could be an elevated level for detoxification of DDT. Furthermore, the GST activity in DDT-resistant An. culicifacies and An. annularis was significantly higher than that in the DDT-susceptible An. fluviatilis, which had a GST activity of 20.0 micromol/min/mg. Also, the GST-mediated DDT detoxification was confirmed by comparing GST activity in wild-caught females with that in their F1 progeny.

The molecular mechanism for DDT detoxification in Anopheles gambiae: A molecular docking study

The epsilon class glutathione-S-transferase of Anopheles gambiae, agGSTe2, is capable of metabolizing DDT. A molecular docking analysis of DDT with agGSTe2 support an E2 elimination mechanism wherein the glutathione sulfur serves as the base to convert DDT to DDE.

50 years in insect toxicology: 1956–2006

50 years in insect toxicology: 1956–2006

Profiling of abundant proteins associated with dichlorodiphenyltrichloroethane resistance in Drosophila melanogaster

Dichlorodiphenyltrichloroethane (DDT) metabolism-based resistance in Drosophila melanogaster is a complex metabolic system associated with the transcription of detoxification related genes, ion transport, lipid and sugar metabolism pathways. However, little is known about the differences regarding the proteome of field- and laboratory-selected resistant Drosophila genotypes. We investigated the impact of DDT resistance in the abundant proteome of field- and laboratory- selected resistant Drosophila using a two-dimensional gel electrophoresis DDT reference map. Proteomic profiling was performed in two DDT susceptible genotypes (Canton-S and 91-C) and three DDT resistant lines (Rst(2)DDT(91-R), Rst(2)DDT(Wisconsin) and Rst(2)DDT(Hikone-R)). Protein spots were stained with Coomassie blue and compared using PDQuest software. Selected protein spots were cut out and analyzed using matrix assisted laser desorption-time of flight mass spectrometry. Querying the NCBInr. 10.21.2003 database with mass spectrometric data yielded the identity of 21 differentially translated proteins in Rst(2)DDT(91-R), Rst(2)DDT(Wisconsin) and Canton-S representing proteins putatively involved in biochemical pathways such as glycolysis and gluconeogenesis, the pentose phosphate pathway, the Krebs cycle and fatty acid oxidation. We hypothesize that both strategies are aimed to use of the pentose phosphate pathway to increase glucose utilization while Rst(2)DDT(91-R) relies primarily on glycolysis to produce reduced NADP and increase DDT detoxification. DDT exposure in Canton-S induced six proteins, while four proteins were repressed in Rst(2)DDT(Hikone-R). Our data suggest that insecticide resistance appears to impact different metabolic pathways in Drosophila genotypes selected with the same pesticide (DDT).

The contribution of metabolism to pyrethroid and DDT resistance in the horn fly (Diptera: Muscidae).

Pyrethroid resistance developed rapidly in a laboratory strain of the horn fly, Haematobia irritans (L.), which was selected in each successive generation with approximate LC50’s of orally-administered technical permethrin. The topical LC50’s for cis - and trans -permethrin after 7-10 generations of selection were 21.5 and 26.9 times greater, respectively, for flies from the selected strain (R) than those from an unpressured susceptible (S) strain. After 30 generations of selection, LC50’s for the permethrin isomers increased to 48.9 and 70.5 times, respectively. The R flies were cross-resistant to fenvalerate and DDT but not to stirofos or coumaphos. Studies of factors influencing development of resistance to trans -permethrin indicated no important differences between Sand R strains in rates of absorption, internal accumulation, or excretion following topical applications. Studies of the metabolism of [14C] cis - and trans -permethrin by R flies suggested that enhanced metabolic detoxification was not a contributing factor during the early stages (ca. 25-fold level) of resistance development, but was a factor at higher levels of resistance. Metabolic detoxification of DDT was significantly greater in R flies than in S flies, but the level of enhancement (ca. 2 times) was insufficient to account for the major differences between the strains in susceptibility to the compound. Coadministration of piperonyl butoxide (PBO, a microsomal oxidase inhibitor) with cis - or trans -permethrin and fenvalerate caused a major reduction in metabolic detoxification, while a hydrolase inhibitor (DEF) had only a slight effect on metabolism. Tests of the topical toxicity of trans -permethrin to R flies demonstrated that coadministration of PBO caused a 10-fold reduction in the LC50 and DEF caused a 4-fold reduction. Although there is no reason to doubt that target site insensitivity is the major factor in pyrethroid resistance in the horn fly, this study provides direct evidence that enhanced metabolic detoxification can also be a contributing factor.

Comparative acute toxicity of DDT metabolites among American and European species of planarians

1. DDT metabolism in a North American species of planarian leads to the formation of metabolites more toxic than the parent compound. 2. The increased toxicity of DDT metabolites is similar to acute toxicity data reported previously in a European species. 3. It is suggested that planarians lack a direct mechanism for DDT detoxification, since two North American and one European species are known to metabolize DDT initially to DDE and DDD.

Detoxification of DDT by the Perfused Bovine Liver1,2

Five bovine livers were isolated and perfused with DDT [2,2-bis (p-chlorophenyl)-1,1,1-trichloroethane] to study the ability of liver to detoxify chlorinated hydrocarbons. A perfusion apparatus was designed and constructed so as to minimize contact of perfusate or tissue vrith metal or plastic.Within fifteen minutes after dosing there was a measurable decrease of DDT in the perfusate and a significant increase in DDD [2,2-bis (p-chlorophenyl) 1,1-dichloroethane]. Levels of DDE (2,2-bis (p-chlorophenyl) 1,1-dichloroethylene] were low at the beginning and increased only slightly during the experiment. It was demonstrated that isolated perfused bovine liver was capable of dehalogenating DDT to its less toxic analog, DDD. Production of DDE was probably due to catalytic action caused by hemoglobin breakdown. At the end of each two-hour perfusion experiment the livers still had a natural appearance and probably could have been used longer had it been necessary.

Column partition chromatography of DDT and related compounds

The separation of DDT, certain of its homologs and analogs (DDE, DDD, DBP, Kelthane, and FW-152) which are of interest in studies of detoxification of DDT, and some derivatives of DDT (Cl-DDT, Ac-DDT) was achieved by column chromatography of the compounds partitioned between 2,2,4-trimethylpentane (moving phase) and 3-methoxypropionitrile (stationary phase) on cellulose powder. Measurement of the absorbancies of the effluent fractions at 235 and 268 mμ served as the primary quantitative and qualitative assay. A colorimetric procedure, modifying earlier applications of the Fujiwara reaction, was developed to measure Kelthane and Ac-DDT.

Chemical Aspects of the Fight Against Insects

AbstractA survey is given of the existing knowledge on the mode of action of DDT and analogous compounds, especially the 1,1‐diaryl‐2,2,2‐trifluoroethane derivatives, as well as DDT synergists. The relative importance of DDT dehydrochlorinase for the detoxification of DDT is discussed.The nutritive requirements of the insects and their differences from those of higher animals are surveyed. Of particular interest are the sterol requirements of the insects, which are incapable of synthesizing these compounds, and the biological availability of “unnatural” analogs of the sterols.

Mode of action of DDT on the housefly, Musca nebulolinn

The penetration of topically applied DDT through the cuticle of the housefly, Musca nebulolinn. and its transference and distribution in various tissues of the insect have been studied. The detoxification and excretion of the insecticide from the housefly has also been investigated. The mechanism of intoxication and detoxification of DDT in nerve ganglion has been found to be similar to that in the whole fly. The nature of the solvent used in the application of the insecticide influences the penetration and detoxification of the toxicant.

Adsorption of DDT and Its Absorption and Conversion to DDE by House Flies Exposed to Residues

The rate of adsorption of DDT from residues on glass surfaces and its absorption and conversion to DDE (1,1-dichloro-2,2- bis(p-chlorophenyl)ethylene) was evaluated in a normal colony and three resistant colonies of house flies (Musca domestica L.). External DDT increased with the time of exposure and with fly activity in two of three colonies. Different colonies of flies picked up DDT at different rates. Detoxification of DDT to DDE increased with time of exposure. Knocked-down flies showed more absorbed DDT than those still up at the end of the exposure period, and less conversion of DDT to DDE. Susceptible flies showed the presence of a DDT-DDE detoxifying mechanism after prolonged exposure to DDT residues, and a colony selected with malathion converted DDT to DDE in short exposures.

Dosage–Mortality Curves for Houseflies Susceptible and Resistant to DDT

A RECENT paper by Hewlett1 has directed attention to the fact that the slopes of dosage–mortality curves for houseflies resistant to DDT are less steep than those for houseflies susceptible to DDT ; he explained this in terms of (1) the relation between the amount of DDT absorbed by flies and the external dose ; and (2) a possible variation from fly to fly of the DDT exerting a toxic effect at the primary site of action, a variation brought about or intensified by enzymatic detoxification of DDT in resistant flies. An alternative explanation of the phenomenon would be that DDT resistance in houseflies is genetically controlled, and that very few of the strains of insects so far examined represent genetically pure lines.

INTERPRETATION OF DOSAGE‐MORTALITY DATA FOR DDT‐RESISTANT HOUSEFLIES

The slopes of the lines relating probit mortality to the log.‐dose of DDT are generally lower for resistant than for susceptible strains of houseflies. Two effects that could each account for this are discussed. The first concerns the relation of the amount of DDT absorbed to the dose; the conditions under which it would occur are stated, and published data on the absorption are analysed. The second concerns the variability from fly to fly of the amount of DDT exerting a toxic effect at the primary site of action, a variability that would seem to be brought about, or greatly intensified, by the enzymatic detoxification of DDT in resistant flies. Both mechanisms may occur, reinforcing one another.

Detoxification of Ddt in Relation to Cytochrome Oxidase Activity in Resistant and Susceptible House Flies

The complex nature of the problem of insect resistance to insecticides has recently given an impetus to a wide variety of investigations along lines of insect morphology, physiology, behavior, and genetics. As a result of this voluminous work (a great part of which is as yet unpublished) it has become increasingly evident that resistance to one or more insecticides in various insect species and among strains of a single species cannot be characterized by a single common factor.

DDT Detoxification Product in American Cockroaches

DDT Detoxification Product in American Cockroaches

DDT detoxification product in American cockroaches.

DDT detoxification product in American cockroaches.

DDT Detoxification Product in American Cockroaches

DDT Detoxification Product in American Cockroaches