Dimethyl Phosphorodithioate Research Articles

Preparation of Anti-idiotype Antibodies of O,O-Dimethyl Organophosphorus Pesticides by Phage Display Technology

Abstract Anti-idiotype antibodies (AId or Ab2) can be used to develop a noncompetitive immunoassay for hapten molecules. In this work, generic hapten, S-carboxyethyl O,O -dimethyl phosphorodithioate (CMP), was immobilized on sepharose and then used for purification the class-specific antibodies of organophosphorus pesticides. Affinity-purified positive and negative primary antibodies were used for biopanning of AIds from phage display antibody library. After three rounds of panning, 3 α-AId and 9 β-AId positive clones were obtained. Clones D11 and B9, identified as β-AId and α-AId respectively, were selected to develop a noncompetitive immunoassay system. The IC 50 value and detection limit of this method for malathion were calculated to be (113.7 ± 34.18) (g L −1 and 10.54 (g L −1 , respectively.

Electron-Capture Gas Chromatographic Determination of Alkyl Thiophosphates as Pentafluorobenzyl Derivatives

Abstract An improved and sensitive gas chromatographic method has been established for the determination of four dialkyl thiophosphates including dimethyl phosphorothioate, diethyl phosphorothioate, dimethyl phosphorodithioate and diethyl phosphorodithioate. The method is based on the derivatization of the thiophosphates with pentafluorobenzyl bromide, using hexadecyltrimethylammonium bromide as a phase transfer catalyst. The resulting derivatives were separated on an SE-54 capillary column and detected by an electron-capture detector. Several parameters affecting the derivatization of the related thiophosphates were investigated. Determinations of the thiophosphates were attainable at pmol levels. The detection limits (signal to noise ratio of 5) of dimethyl phosphorothioate, diethyl phosphorothioate, dimethyl phosphorodithioate and diethyl phosphorodithioate in aqueous sample were at about 8.3, 6.0, 5.7 and 5.6 nM, respectively. Application of the method to the analysis of the thiophosphates spiked in p...

Roles of fungi and bacteria in the mineralization of the pesticides atrazine, alachlor, malathion and carbofuran in soil

Different roles for fungi and bacteria in the biotransfonnation pathways of pesticides in the soil were demonstrated. The pesticides studied were malathion (diethyl mercaptosuccinate S-ester 0,0 dimethyl phosphorodithioate), alachlor (2-chloro- N-[2-6-diethylphenyl]- N-[methoxy methyl] acetamide), atrazine (2-chloro-4-ethylainino-6-isopropylamino-l,3,5-triazine-2,4 diamine) and carbofuran (2,3-dihy-dro-2,2-dimethyl-7-benzofuranyl methylcarbamate). The mineralization of alkyl-side chains of alachlor and alkyl-amino-side chains of atrazine was found to be mainly due to fungal activity. Neither heterocyclic ring-labelled atrazine nor aromatic ring-labelled alachlor were degraded when fungi or bacteria were separately inhibited. The mineralization of carbofuran and malathion was mainly due to bacterial activity. These results indicate that the biodegradation of pesticides in the soil is performed by both fungi and bacteria. The mechanism of this phenomenon and the mode of action of the two microbial groups are discussed.

Dialkylphosphorus metabolites in the urine and activities of esterases in the serum as biochemical indices for human absorption of organophosphorus pesticides

Ninety-seven agricultural workers were monitored for absorption of the organophosphorus pesticides methidathion, vamidothion, and azinphos-methyl, which were sprayed in an orchard during two seasons. Low levels of only one dialkylphosphorus metabolite (dimethyl phosphorothioate) were found in only eight workers in pre-exposure urine samples. More than one dialkylphosphorus metabolite was detected in almost all exposed individuals in after-exposure urine samples. The highest concentrations were measured after exposure to azinphos-methyl; the median concentrations of dimethyl phosphorodithioate and dimethyl phosphorothioate were 0.92 and 0.78 nmol/mg creatinine with a concentration range up to 14.3 and 53.7, respectively. Three diethylphosphorus metabolites were also detected in some samples, but at lower concentrations. Cholinesterase activities were decreased (31-48%) in the serum of 12 workers; four of those workers had no dialkylphosphorus metabolites in the urine. Paraoxonase and arylesterase activities in the serum were unaffected by the absorption of pesticides, and there was no correlation between the activities of these esterases and the metabolite concentrations in the urine. This study confirmed that dialkylphosphorus metabolites in the urine are a more sensitive index of absorption than cholinesterase inhibition in the serum but lack of correlation between cholinesterase inhibition and metabolite concentration indicates that both parameters should be monitored.

The metabolites of organophosphorus pesticides in urine as an indicator of occupational exposure

The differences in the degree in workers’ exposure to organophosphorus pesticides during the spraying of an apple‐orchard were assessed from the urinary content of metabolites: dimethyl phosphorothiolate potassium salt (DMPThK) for Demeton‐S‐methyl and dimethyl phosphorothionate and phosphorodithioate potassium salts (DMTPK and DMDTPK) for Azinphos‐methyl and Methidathion. The highest median concentrations of the metabolites in the urine samples collected after two to three days of work with the pesticides were determined in the mixers preparing pesticide solutions: DMPThK 83ng cm‐3 (N = 7) after exposure to Demeton‐S‐methyl; DMTPK 2040 and DMDTPK <20n gcm‐3 (N =7) after exposure to Azinphos‐methyl; DMTPK 501 and DMDTPK 88 ng cm‐3 (N = 6) after exposure to Methidathion. The applicators (sprayers) were the second most exposed group: DMPThK 30 ng cm‐3 (N = 6) after exposure to Demeton‐S‐methyl; DMTPK 433 and DMDTPK <20 ng cm‐3 (N = 7) after exposure to Azinphos‐methyl; DMTPK 45 and DMDTPK <20 ng cm‐3 (N = 1...

Eiotransformation and tissue binding of arsenic in mice and rabbits

Different roles for fungi and bacteria in the biotransfonnation pathways of pesticides in the soil were demonstrated. The pesticides studied were malathion (diethyl mercaptosuccinate S-ester 0,0 dimethyl phosphorodithioate), alachlor (2-chloro-N-[2-6-diethylphenyl]-N-[methoxy methyl] acetamide), atrazine (2-chloro-4-ethylainino-6-isopropylamino-l,3,5-triazine-2,4 diamine) and carbofuran (2,3-dihy-dro-2,2-dimethyl-7-benzofuranyl methylcarbamate).The mineralization of alkyl-side chains of alachlor and alkyl-amino-side chains of atrazine was found to be mainly due to fungal activity. Neither heterocyclic ring-labelled atrazine nor aromatic ring-labelled alachlor were degraded when fungi or bacteria were separately inhibited.The mineralization of carbofuran and malathion was mainly due to bacterial activity.These results indicate that the biodegradation of pesticides in the soil is performed by both fungi and bacteria. The mechanism of this phenomenon and the mode of action of the two microbial groups are discussed.

Biochemical studies of some hydrolytic enzymes in malathion treated germinating seeds ofVigna sinensis(l): effect of growth hormone supplementation

Studies have been carried out on the different hydrolytic enzymes of the germinating seeds of V. sinensis (L) by exposing them to various concentrations of malathion (O, O dimethyl phosphorodithioate of diethyl mercaptosuccinate), an organophosphorus insecticide. At 50 ppm the insecticide induces the seedling growth and at 400 ppm caused a significant inhibition. On simultaneous application of either of the plant hormones, i.e., IAA, GA3 and kinetin with different concentrations of malathion, it was found that there was a trend to overcome of malathion inhibition of seedling growth. It was also found that treatment of seeds with growth hormones, at 400 ppm malathion exposure, helps to restore the normal activities of certain hydrolytic enzymes, which showed otherwise, significant altered activities. Kinetic studies show that the stimulation of acid phosphatase activity due to malathion exposure was non‐competitive in nature.

Transformation of DAEP (S-(2-acetylaminoethyl) dimethyl phosphorodithioate) under various oxidative conditions.

14C-DAEP [S-(2-acetylaminoethyl) dimethyl phosphorodithioate] was subjected to four different oxidative conditions, and the products were identified. On peracid oxidation in dichloromethane, DAEP gave the oxon (1) predominantly, and 2-acetylaminoethyl dimethoxyphosphinyl disulfide (3), N-acetylcysteamine (10), its oxidized dimer (11) and a further oxidation product of compound 11. This indicates that an unstable phosphorus oxythionate was initially formed, which lost sulfur, was rearranged, and hydrolyzed to give these products. Under other conditions, phosphinyl disulfide 3 was not found. DAEP was metabolized in vitro with a rat liver microsome-NADPH system via oxidation. The aqueous reaction condition prevented the formation of compound 3 from the intermediate, which predominated as well as the oxon formation under anhydrous or close conditions. The formation of various products with sunlight irradiation on glass plates or on bean leaves could be interpreted by oxidation at P=S, C1 and C2 positions, demethylation, and deacetylation, followed by further transformation. The initial formation of phosphorus oxythionate seems to play an important role in the oxidation of the organothionophosphorus compound.

Microbial cleavage of various organophosphorus insecticides

Bacteria able to utilize Aspon, Azodrin, Dasanit, diazinon, malathion, Orthene, parathion, Trithion, dimethoate, Dylox, methyl parathion, and Vapona as sole phosphorus sources were isolated from soil and sewage. Individual isolates used from 3 to 10 of these insecticides as sole phosphorus sources. The extent of growth of two Pseudomonas strains in media containing diazinon and malathion was in the range expected from the amount of insecticide supplied, and their proliferation resulted in disappearance of the chemical. Resting cells of the pseudomonads derived from cultures grown on diazinon or malathion but not orthophosphate caused extensive destruction of these two organophosphates in the presence or absence of chloramphenicol. Extracts of the two bacteria derived from organophosphate-grown cultures catalyzed the disappearance of Aspon, Azodrin, Dasanit, diazinon, malathion, Orthene, parathion, and Trithion but not dimethoate, Dylox, methyl parathion, and Vapona. Results from gas chromatographic analysis suggested that the extracts formed dimethyl phosphate from azodrin, dimethyl phosphorodithioate from malathion, diethyl phosphorodithioate from Trithion, and diethyl phosphorothioate from Dasanit, diazinon, and parathion. Dimethyl phosphate, dimethyl phosphorothioate , dimethyl phosphorodithioate, diethyl phosphate, and diethyl phosphorothioate were not used by the pseudomonads as sole phosphorus sources.

Malathion Degradation by an Arthrobacter Species

AbstractThe dissipation of malathion from agricultural soils has been shown to involve both chemical and biological mechanisms, with biodegradation being of substantial magnitude. This investigation was conducted to (i) isolate from soil by enrichment techniques bacterium or several bacteria capable of readily metabolizing malathion, and (ii) isolate and identify the malathion metabolites resulting from this microbial degradation. Of 18 soil bacteria examined, 5 were capable of utilizing the malathion molecule with degradation of added insecticide ranging from 47 to 95%. The most efficient malathion utilizer, an Arthrobacter species, degraded malathion to malathion half‐ester, malathion dicarboxylic acid, potassium dimethyl phosphorothioate, potassium dimethyl phosphorodithioate, and one other unidentified metabolite. O‐desmethyl malathion, potassium salt, was also produced, but the mechanism involved was nonbiological in nature. Malathion dissipation was monitored by electron‐capture gas‐liquid chromatography, and metabolites were identified by thin‐layer chromatography and infrared spectroscopy.

Acetylcholinesterase Toxicity of Malathion and Its Metabolites

AbstractMalathion, under in vitro laboratory conditions, is readily degraded by an Arthrobacter species to four metabolites—malathion half‐ester, malathion dicarboxylic acid, potassium dimethyl phosphorothioate, and potassium dimethyl phosphorodithioate. However, it is not clear whether or not this degradation represents a simultaneous detoxication of the malathion molecule. With this in mind, the relative toxicity of each of the four metabolites to bovine acetylcholinesterase was determined manometrically with the Warburg apparatus. Malathion half‐ester retained roughly one‐third the enzyme toxicity of unaltered malathion, while the other metabolites showed essentially no enzyme inhibition. It was concluded that while microbial conversion of malathion to malathion halfester may well represent complete malathion degradation, it does not constitute complete insecticide detoxication.

Tests of Chemical Control of the Cereal Leaf Beetle12

Stauffer N-2596 ( S-(p -chlorphenyl) O -ethylphos-phonodithioate), and Fisons NC-6897 (2,3-(isopropylidenedioxy) phenyl methylcarbamate), showed promise, and the effectiveness of endosulfan; Allied GC-9160 (ethyl 1,1a,3,3a,4,5,5,5a,5b,6-decachlorooctahydro-2-hydroxy-1,3,4-methano-2 H -cyclobuta[ cd ]pentalene-2-levulinate); carbofuran; carbaryl; Landrin® (3,4,5-trimethy1-phenyl methylcarbamate, 75%; 2,3,5 trimethylphenyl methylcarbamate, 18%); and Stauffer N-4543 ( O- isobutyl ethylphosphonodithioate S-ester with N -(mercaptomethyl) phthalimide), was confirmed for control of Oulema melanopus (L.) in oats in a series of field tests during 1968-70. Padan® ( S,S' -[2-(dimethylamino) trimethlyene] bis (thiocarbamate), hydrochloride), Mobam® (benzo[b]thien-4-yl methylcarbamate), propoxur, Supracide® ( S -(2-methoxy-5-oxo-△2-1,3,4 thiadiazolin-4-yl)-methyl) O,O -dimethyl phosphorodithioate), Allied GC-6506 (dimethyl p -(methylthio) phenyl phosphate), duPont 1410 (methyl N,N -dimethyl- N' -[ (methylcarbamoyl) oxy]-lthiooxamimidate), and methomyl gave short residual protection of the plants. Cyolane® (cyclic ethylene P,P-diethyl phosphonoclithioimidocarbonate) showed evidence of inhibiting feeding of the larvae. Monocrotophos gave a slow kill of the pest. Fenitrothion, methyl parathion, spores of a Hungarian strain of Bacillus thruingiensis Berliner, phosalone, and Bithion® O,O' -(thiodi- p -phenylene) ( O,O,O',O' -tetramethyl phosphorothioate), were unsatisfactory for control of the pest.

Effects of four lights on malathion residues on glass beads, sorghum grain, and wheat grain.

Different regions of light have different photodegradative effects on malathion deposits on glass beads, sorghum g-rain, and wheat grain. Temperature effects of IR light produced the most rapid disappearance of malathion, whereas far UV light, plant GRO, and near UV light exhibited a decreasing order of photodegradative activity. Identified degradation products of malathion were: malaoxon, malathion mono acid, malathion (diacid, O -demethyl malathion, O,O -dimethyl phosphorodithioate, O,O -dimethyl phosphorothioate, dimethyl phosphate, and phosphoric acid. Several unidentified compounds, both thiophosphates and phosphates also were detected.

Control of Rosaceae Branch Borer in Iran1

Various control measures were evaluated against Osphranteria coerulescens Redtenbacher, a serious pest of rosaceous fruit trees in middle and southern Iran. Nine hymenopterous species were observed inside the larval tunnel, and 3 of these, Xorides corcyrensis Kriechbaumer (Ichneumonidae), Eurytoma sp. (Eurytomidae), and Chalcedectus balashowski Steffan (Chalccdectidae) are active larval parasites. A woodpecker, as a larval predator, caused considerable mortality to the pest. The borer appears to he prevalent in light soils with a low water-holding capacity. Spraying with Cidial® (ethyl mercaptophenylacetate S -ester with O,O -dimethyl phosphorodithioate) and monocrotophos gave considerable control. Under local conditions, cutting infested twigs between July 15 and Aug. 15 with long pruning shears is the simplest, safest, and cheapest method of control.

Greenbug Control on Grain Sorghum and the Effects of Tested Insecticides on Other Insects1

A new biotype of Schizaphis gramimun (Rondani) caused severe and widespread damage to sorghum, Sorghum bicolor (L.) Moench, in the summer of 1968. Screening tests and refinement of application rate studies were conducted in 1968 and 1969 to determine if compounds used in greeubug control on wheat could be used effectively also against this biotype. The most feasible chemicals, considering both insecticidal and nonphytotoxic properties, were disulfoton, parathion, diazinon, demeton, and ULV malathion. Carbophenothion, although somewhat slower acting, was also usually very effective. Supracide® ( S -((2-methoxy-5-oxo-∆2-l,3,4-thiacliazolin-4-yl) methyl) O,O -dimethyl phosphorodithioate), while not very effective in the 1968 studies, significantly reduced greeubug populations in the 1969 tests. Most of the insecticides were found to give reductions also in populations of the corn leaf aphid Rhopalosiphum maidis (Fitch). Fall armyworm, Spodoplera frugiperda (J. E. Smith), and flea beetle population differences following insecticidal treatments were not significant. Of the beneficial insects monitored, the primary species present were the convergent lady beetle, Hippodamia convergens Guerin-Meneville, and various parasitic Hymenoptera. In general the more effective the insecticide in controlling the greenbug, the greater its suppressive effect Avas on beneficial insect populations. However, demeton applied at 0.5 lb active ingredient per acre gave satisfactory greenbug control and spared much of the beneficial insect population.

Organophosphorus and Carbamate Insecticides as Substitutes for DDT in Controlling the Tobacco Flea Beetle on Flue-Cured Tobacco1

Field experiments conducted in North Carolina during 1961-65 to compare the residual effectiveness of insecticidal sprays against Epitrix hirtipennis (Melsheimer) on flue-cured tobacco showed that, for the number of days indicated after application, the following treatments provided control similar to that obtained with 1 lb per acre of DDT: (1) for 10 days. 0.5 lb of carbofuran, Dasanit®( O, O -dicthyl O -[ P -(methylsulfinyl) phenyl] phosphorotluoate), dinwthoate. Gardona® (2-chloro-1-(2-4,5-trichlorophenyl) vinyl dimethyl phosphate), Imidan® ( O, O- dimethyl S-phthalimidornethyl phosphorodithioate), and Supracide® (S-((2-methoxy-5-oxo-∆2-1,3,4-thiadiazolin-4-yl) methyl) O, O -dimethyl phosphorodithioate), and 1 lb of aminocarb and MCA-600 (benzo[b]thien-4-yl methylcarbamate), (2) for 6 days, 0.25 lb of azinphosmethyl. 0.5 lb of dicrotophos and phosphamidon, and 1 lb of carbaryl, and (3) for 3 days, 0.25 lb of parathion and 1 lb of carbanolate. One-fourth lb of methyl parathion, 0.5 lb of diazinon, endosulfan, malathion, and naled, and 1 lb of TDE provided control inferior to that of 1 lb of DDT for 3 days and no significant control thereafter. Variable control was obtained with monocrotophos.

Organophosphorus and Carbamate Insecticides as Substitutes for DDT in Controlling the Tobacco Flea Beetle on Flue-Cured Tobacco

Field experiments conducted in North Carolina during 1961-65 to compare the residual effectiveness of insecticidal sprays against Epitrix hirtipennis (Melsheimer) on flue-cured tobacco showed that, for the number of days indicated after application, the following treatments provided control similar to that obtained with 1 lb per acre of DDT: (1) for 10 days. 0.5 lb of carbofuran, Dasanit®( O, O -dicthyl O -[ P -(methylsulfinyl) phenyl] phosphorotluoate), dinwthoate. Gardona® (2-chloro-1-(2-4,5-trichlorophenyl) vinyl dimethyl phosphate), Imidan® ( O, O- dimethyl S-phthalimidornethyl phosphorodithioate), and Supracide® (S-((2-methoxy-5-oxo-∆2-1,3,4-thiadiazolin-4-yl) methyl) O, O -dimethyl phosphorodithioate), and 1 lb of aminocarb and MCA-600 (benzo[b]thien-4-yl methylcarbamate), (2) for 6 days, 0.25 lb of azinphosmethyl. 0.5 lb of dicrotophos and phosphamidon, and 1 lb of carbaryl, and (3) for 3 days, 0.25 lb of parathion and 1 lb of carbanolate. One-fourth lb of methyl parathion, 0.5 lb of diazinon, endosulfan, malathion, and naled, and 1 lb of TDE provided control inferior to that of 1 lb of DDT for 3 days and no significant control thereafter. Variable control was obtained with monocrotophos.

Initial and Residual Activity of Cidial (Phenthoate) Compared with that of Malathion and Lindane on Insects Affecting Stored Products1

The initial activity of Cidial (phenthoate) (ethyl mercaptophenylacetate O, O -dimethyl phosphorodithioate) was compared with that of lindane and malathion on the following insects affecting stored products: Mediterranean flour moth, Anagasta huehniella (Zeller), larvae; khapra beetle, Trogoderma granarium Everts, larvae; lesser grain borer, Rhyzopertha dominica (F.), adults; saw-toothed grain beetle OryzaePhilus surinamensis (L.), adults; canfused flour beetle, Tribolium confusum Jacqueline duVal, larvae and adults; yellow mealworm, Tenebrio molitor L., larvae and adults; granary weevil, Sitophilus granaries (L.), adults; rice weevil, Sitophilus oriya (L.), adults. Cidial proved to be more effective than the other 2 products. Further tests were conducted to compare the residual activity of the 3 compounds. Cidial sprayed at 8 and 4 ppm on wheat gave almost complete control for at least I year of all species except T. granarium and A. kuehniella (poor control obtained after a few months). When applied at 2 ppm by spraying and at 4 ppm by dusting, this product provided almost complete control of T. confusum larvae and S. oryzae adults for I year and of some of the other species for a few months. Larvac;, used as a dust at 2 and 4 ppm, was fully effective for I year against R. dominica, S. granarius ., and S. oryzae and for a few months against T. confusum larvae; its toxicity to all the other species was limited from the outset. Malathion sprayed at 8 ppm gave almost complete kill of T. confusum larvae and S. oryzae adults for 3 months and of S. granaries for 2 months. None of the insecticides affected the germination of the seeds to any extent for I year after treatment.

Laboratory and Field Evaluation of Insecticides Against the Egyptian Cotton Leafworm

Several new insecticides and mixtures were evaluated in the field for control of Spodoptera littoralis (Boisduval). Bioassay was performed in the laboratory with S. littoralis larvae, to determine effectiveness of insecticide residues from the field. Many materials showed strong ovicidal action with some having LT50 values extending to 9–10 days. As larvicides, none of the tested materials had an LT50 longer than 7 days. There was good correlation between laboratory and field tests. Abate® (O, O -dimethyl phosphorodithioate O, O -diester with 4,4′-thiodiphenol) and CIBA 8514 (NŃ -(4-chloro- O -tolyl)- N, N -dimethylformamidine) were good ovicides but poor larvicides. Considering results from all tests, the 2 experimental insecticides, E. I. 47031 (cyclic ethylene (diethoxyphosphinyl) dithioimidocarbonate), E. I. 47470 (cyclic propylene (diethoxyphosphinyl) dithioimidocarbonate) -and a mixture of endrin-Bidrin® (3-hydroxy- N, N -dimethyl- cis -crotonamide dimethyl phosphate) were the most promising.

Chemical Control of the Sunflower Moth on Sunflowers1

Tests were conducted to determine the effectiveness of 9 insecticides for control of Homoeosoma electellum (Hulst). Tests at College Station, Texas, showed that 2 applications of methyl parathion, endosulfan, diazinon, and malathion reduced the number of larvae and increased yields. Tests at McGregor, Texas, showed that only endosulfan and carbaryl reduced the larval infestation following 1 application; however, they did not increase yields. Two applications of GS-13005, (O,O -dimethyl phosphorodithioate Sester with 4-(mercaptomethyl)-2-methoxy-∆2-1,3,4-thiadiazolin-5-one), azinphosmethyl, methyl parathion, carbaryl, azinphosmethyl ultra-low-volume (ULV) and methyl parathion ULV increased yields. Plots treated 3 times, except those treated with malathion ULV, had lower infestations than the check plots and yields were increased except when treated with trichlorfon. Yields were significantly increased when methyl parathion, endosulfan, or carbaryl were applied at 5-day intervals. Applications at pre-flower, or at 10% flower, in most cases, did not significantly reduce the number of larvae or increase seed yields. Generally, insecticides applied at the 50 and 100% flower stages were most effective.