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1.
The toxicity of carbaryl to three species of fleshflies Sarcophaga bullata Parker, S. crassipalpis Macquart, and S. argyrostoma (Robineau-Desvoidy) varied considerably with age and sex. In contrast, the susceptibility of a blowfly, Phormia regina (Meigen) to carbaryl decreased with age and that of two muscid flies, Musca autumnalis DeGeer and Stomoxys calcitrans (L.), remained relatively constant. The synergistic activity of piperonyl butoxide varied inversely with the innate toxicity of carbaryl to each species suggesting that the observed age- and sex-dependent variations in carbaryl toxicity result mainly from differences in detoxifying capability. This was supported by in vitro measurements of oxidative microsomal metabolism. It was further established that differences in the rates of penetration and excretion of carbaryl and in the susceptibility of the head cholinesterase to carbaryl inhibition were of little importance in determining the susceptibility of the flies to this insecticide. 相似文献
2.
A study of the metabolism of 14C-labeled dieldrin, DDT, malathion, and carbaryl during penetration of the isolated midgut of two insects (Blaberus discoidalis and Manduca sexta) and a section of the intestine of a mammal (Mus musculus) is reported. There was appreciable metabolism of malathion during penetration, including differences in the activation reaction to malaoxon, between insects and mammals. Metabolism was relatively slow during penetration of carbaryl and the chlorinated hydrocarbon insecticides, and little difference in metabolic patterns was noted among the three species. The penetration studies were supported by experiments in which insecticides were incubated with intact and homogenized midgut preparations. 相似文献
3.
This investigation concerns the binding of DDT, dieldrin, parathion, and carbaryl to macromolecules of rat and roach blood. Plasma was filtered on Sephadex G-200, and the first protein peak (FPP) was used to investigate binding characteristics for the insecticides. Binding was demonstrated to be of a nonspecific hydrophobic nature, except for roach FPP and dieldrin in which, in addition to low-affinity binding, sites for high-affinity binding were also found. Competitive binding experiments were run with cholesterol, estrogen, DDT, and dieldrin. No significant competitive interactions were demonstrated. 相似文献
4.
The effects of aldrin, carbaryl, α- and γ-chlordane, dichlorodiphenyldichloroethane (DDD), dichlorodiphenyltrichloroethane (DDT), dieldrin, endrin, heptachlor, lindane, methoxychlor, and nonachlor on the short-circuit current and resistance of the isolated intact frog skin were studied. The short-circuit current is approximately equivalent to the rate of active transport of sodium, while the resistance indicates the summed ionic permeability of the skin. At a concentration of 2 × 10?4M, only carbaryl, DDD, dieldrin, and lindane produced significant (P<0.05, paired t test) changes in the short-circuit current. Nonachlor produced a decrease (P=0.12) in the short-circuit current and also increased the resistance (P=0.07). DDD, dieldrin, and carbaryl caused significant increases in short-circuit current while at the same time the resistance was significantly decreased. Lindane increased both the short-circuit current and the resistance. It was concluded that the frog skin probably contains effective permeability barriers that prevent externally applied insecticides from reaching the site of active sodium transport. It appeared likely that most of the insecticides produced the observed effects on the frog skin by altering the sodium permeability of the outer barrier. 相似文献
5.
Chlorpyrifos (Dowco 179) and its dimethyl homologue, chlorpyrifosmethyl (Dowco 214), were used to study the influence of the O,O-dialkyl group of organophosphorus insecticides on toxicity, absorption, and metabolism among larvae of the tobacco budworm [Heliothis virescens (F.)] from strains that were resistant (R) and susceptible (S) to methyl parathion. In toxicity tests, chlorpyrifos and chlorpyrifosmethyl were more toxic than methyl parathion to 3rd-stage R larvae but less toxic to S larvae. Chlorpyrifosmethyl was more toxic (3–4 ×) than chlorpyrifos to both strains of larvae, and the results of absorption studies indicated that the toxicity differential of the homologues may be explained in part by the more rapid absorption of the dimethyl form. Studies of the in vivo metabolism of both Dowco compounds indicated that each was degraded mainly by the cleavage of the pyridylphosphate linkage. In vitro tests demonstrated that the NADPH-dependent microsomal oxidases were of primary importance in detoxification, while glutathione (GSH)-dependent mechanisms (aryl- and alkyltransferases) present in the soluble cell fractions were of lesser importance. O-dealkylation occurred only with chlorpyrifosmethyl. The R larvae demonstrated greater capability in detoxifying both compounds in the comparative in vivo and in vitro studies of metabolism, but the differences were more apparent during the 5th instar than during the 3rd instar. 相似文献
6.
Larvae from two strains of the European corn borer, Ostrinia nubilalis (Hübner), were compared for differences in their tolerance and metabolism of carbaryl (1-naphthyl N-methylcarbamate). The Geneva strain was about twice as susceptible to carbaryl, but both Valley and Geneva borers converted carbaryl to oxidative metabolites at similar rates in vivo and in vitro. Maximum carbaryl-metabolizing activity was present in last-instar larvae, particularly in the fat body and gut tissues. However, the specific activity of gut homogenates was highest in the Geneva strain and the specific activity of fat body was highest in the Valley strain. Other differences in the mixed-function oxidase systems of gut and fat body were also found. The major metabolite in vivo and in vitro was hydroxymethyl carbaryl. 相似文献
7.
K.D. Rainsford 《Pesticide biochemistry and physiology》1978,8(3):302-316
The toxicity in the brain of several parathion, fenthion, and fensulfothion insecticides and their toxic metabolites was determined by a technique of directly injecting the compounds into the region of the third ventricle of conscious mice, an area rich in cholinesterase activity. The results were compared on a body weight basis to the toxicity of these compounds when given by ip and oral routes. The results show that there is a direct relationship between the relative inhibition of cholinesterase activity in the brain by the organophosphates (e.g., methyl paraoxon, Sumioxon, and some members of the fenthion series) and the toxicity of these compounds in the brain. Methyl paraoxon and Sumioxon were found to be very toxic in the brain, Sumioxon being three to four times less toxic than methyl paraoxon. This is of the same order of effect of these compounds in inhibiting cholinesterases. It is concluded that any selective effects of Sumithion compared with methyl parathion must be due to the greater rate of metabolism of Sumithion to less toxic metabolites as well as to the lower toxicity of the oxon metabolite and not due to the relative rates of penetration of the toxic oxygen metabolites as previously suggested [J. Miyamoto, Agr. Biol. Chem.28, 422 (1964)]. A gas-liquid chromatographic method was employed to assess the distribution in the brain following intracerebral injection of the parathion-type compounds. The results suggest that there may be intracerebral metabolism of thionophosphates in vivo. 相似文献
8.
The metabolism in vivo and in vitro of [14C]parathion and [14C]paraoxon was studied in a susceptible (LS) and an organophosphorus-resistant (Q) strain of the sheep blowfly, Lucilia cuprina. Both strains detoxified the insecticides in vivo via a number of pathways, but the resistant strain produced more of the metabolites diethyl phosphate and diethyl phosphorothionate. No difference was found between strains in the rate of penetration of the compounds used. Also, in vitro studies showed no difference between strains in the sensitivity of head acetylcholinesterase to inhibition by paraoxon. Both the microsomal and the 100,000g supernatant fractions degraded paraoxon, but resistance in Q could be explained by the eightfold greater rate of diethyl phosphate production with or without added NADPH. Parathion was also degraded to diethyl phosphorothionate by an NADPH-requiring enzyme in microsomal preparations from both strains. However, Q produced significantly more diethyl phosphorothionate in vivo than LS. It was concluded that organophosphorus resistance in Q was due mainly to a microsomal phosphatase hydrolyzing phosphate but not phosphorothionate esters, probably enhanced by a microsomal oxidase detoxifying the latter. 相似文献
9.
Daily 75 mg/kg phenobarbital ip injections for 3 days or 25 ppm dieldrin in the diet of mice for 14 days caused an increase in liver cytochrome P-450 and blood B-esterase. Liver A-esterase was not significantly increased. Under in vitro conditions, phenobarbital and dieldrin induced the oxidative as well as hydrolytic metabolism of dicrotophos, dimethoate, and phosphamidon by liver homogenates or combined microsomes plus 105,000g supernatant fractions. The concentration of dimethoxon was increased more than fourfold by the pretreatments after incubation for 4 hr at 37.5°C with NADPH added. The organophosphorus insecticides used in this study were not metabolized as well by the liver microsomes alone or 105,000g supernatant alone, as by the combination of microsomes and 105,000g supernatant. Under in vivo conditions in mice, phenobarbital and dieldrin treatments increased the urinary recovery of metabolites in the initial 6 hr after [14C]carbonyl-dimethoate or [14C]N-ethyl-phosphamidon administration. Analysis of urine showed that the inducers caused a more than sixfold increase in dimethoxon recovered and twofold increase in water-soluble nontoxic metabolites within 6 hr after dimethoate administration. With phosphamidon both inducers increased the rate of metabolism, and the total recovery in aqueous and chloroform fractions was decreased. These results suggest that increased dimethoate toxicity after phenobarbital and dieldrin treatments in whole animals results from stimulation of the activation of dimethoate to dimethoxon, while the increase in hydrolytic products after both pretreatments results in decreased toxicity of the direct acetylcholinesterase inhibitors, dicrotophos and phosphamidon. 相似文献
10.
F.J. Oppenoorth H.R. Smissaert W. Welling L.J.T. van der Pas K.T. Hitman 《Pesticide biochemistry and physiology》1977,7(1):34-47
The gene producing insensitive acetylcholinesterase in a tetrachlorvinphos-resistant strain of house fly was introduced into the genome of a susceptible strain. The resistance to a number of organophosphorus insecticides, which was high in the original strain (234- and more than 800-fold for paraoxon and tetrachlorvinphos, respectively), was much lower in the resulting strain, ranging from 53-fold for paraoxon to 3.9-fold for tetrachlorvinphos. Synergists further decreased these factors. The reduction in sensitivity of the acetylcholinesterase in vitro was about 20-fold for both inhibitors. The Michaelis parameters for hydrolysis of acetylcholine and acetylthiocholine of the mutant and normal acetylcholinesterase showed only minor differences. An increased rate of metabolism of the insecticides was found in the original strain. In vitro, glutathione-dependent detoxication was from 9- to 120-fold that of a susceptible strain, depending on the insecticide and the conditions used. The enzyme de-alkylated parathion and methylparaoxon, but there was no de-arylation of parathion, although it is important in other strains. In vitro, paraoxon and methylparaoxon were also hydrolysed, and this is not so in the susceptible strain. The high resistance present in the original strain seems to be due to joint action of at least three mechanisms. 相似文献
11.
The comparative ester hydrolysis and selective toxicity of carbamate insecticides were studied in four mammalian species. Hydrolysis rates of carbaryl and ethiofencarb (Croneton) were examined in the rat, mouse, guinea pig, and gerbil. Respiratory 14CO2 resulting from the hydrolysis of orally administered [carbonyl-14C]carbamates (0.2 mg/kg) was taken as measure of in vivo hydrolytic capabilities. Ester hydrolysis was found to be greater for ethiofencarb than for carbaryl in all species tested, although the relative order of hydrolysis among species was the same with both compounds. After 24 hr, gerbils had hydrolyzed 91% of the ethiofencarb and 65% of the carbaryl. Guinea pigs hydrolyzed somewhat less of the compounds, 65 and 58%, but considerably more than rats and mice, about 40 and 25%. Comparing hydrolysis capabilities to acute toxicity data revealed that those species exhibiting the greatest hydrolysis were equally or more susceptible to carbamate poisoning than those having lesser hydrolytic capabilities. While ester hydrolysis destroys the anticholinesterase activity of carbamates, it is clear from these findings that factors other than hydrolysis are largely responsible for the variation in toxicity of the carbamates to different mammalian species. 相似文献
12.
Inhibition of permethrin-hydrolyzing enzymes from larvae of the porina moth Wiseana cervinata has been examined in vivo and in vitro. Significant inhibition was shown by carbaryl and pirimiphos-methyl. 1-Dodecylimidazole substantially inhibited permethrin hydrolysis only in liver insects. The triphenylmethane dye tetrabromophenolphthalein was a moderate inhibitor only in vitro. TMDM (bis(N-dimethyl-4-aminophenyl)methane) had little effect on hydrolysis. These observations extend the range of species and substrates for which the triphenylmethane dyes and 1-dodecylimidazole are useful inhibitors of insecticide metabolism. 相似文献
13.
A. Ben-Aziz J. Meisner N. Aharonson K.R.S. Ascher 《Pesticide biochemistry and physiology》1976,6(1):58-64
The ingestion and excretion of sublethal doses of phosfolan, monocrotophos, parathion, and leptophos were studied in larvae of the Egyptian cotton leafworm, Spodoptera littoralis Boisd. Styropor (foamed polystyrene) lamellae treated with insecticide-sucrose mixtures were fed to the larvae and recovery of the undecomposed insecticides from the feces could be estimated by gas-liquid chromatography, without any cleanup of the sample. The insecticidal residues on Styropor were found to be stable for 5 days.As regards the percentage of insecticide recovered from the feces, two groups could be distinguished: (a) leptophos, practically complete; parathion, 59–67%; b) phosfolan, 10–23%; monocrotophos, 4–7%. A tentative hypothesis was advanced that both oral toxicity of the four compounds for S. littoralis larvae and their subsequent recovery in the feces were related to water solubility. 相似文献
14.
The absorption and metabolism of topical doses of carbaryl by larvae of the gypsy moth, Lymantria dispar (L.), were determined using 14C-ring-labeled material. Carbaryl penetration followed four distinct phases of linear absorption, i.e., 0–5 min, 5–60 min, 1–3 hr, and 3–12 hr; the absorption rates for the four phases were 2.8, 0.57, 0.07, and 0.02% per minute, respectively. Ninety percent of the total metabolism of carbaryl occurred within the first 3 hr; over the next 9 hr, metabolism was exceedingly slow with a linear rate of ca. 0.8% per hour. Carbaryl was always the major radiocarbon in the larvae and the feces, amounting to ca. 16 and 9%, respectively, at 12 hr. At 12 hr the metabolite composition was 5-hydroxy carbaryl >N-hydroxy carbaryl > 1-naphthol > 4-hydroxy carbaryl > 5,6-dihydro-5,6-dihydroxy carbaryl. Small amounts of an additional product were detected but not identified. Much of the excretion of carbaryl and metabolites occurred without conjugation. The amounts of carbaryl metabolized by second, third, fourth, and fifth instars were directly correlated with the insecticide tolerances and mixed-function oxidase activity of the various larval stages. The synergistic action of 2,6-dichlorobenzyl-2-propynyl ether and piperonyl butoxide was also correlated with inhibition of the oxidative pathway. 相似文献
15.
Adult mosquitoes from two strains of Anopheles gambiae and from three strains of Anopheles stephensi were exposed to 0.25% fipronil‐treated papers in WHO test kits or to 500 mg fipronil m−2 impregnated mosquito netting in bioassay spheres. For comparison, tests were also carried out with the pyrethroid permethrin, using the same methods and doses, and on papers treated with 0.4 and 4% of the cyclodiene insecticide dieldrin. Compared with the same doses of permethrin, fipronil showed less and delayed activity. Two of the An stephensi strains were resistant to fipronil and dieldrin. To investigate whether this was due to a resistance mechanism in the An stephensi strains acting against both insecticides, the most fipronil‐ and dieldrin‐tolerant strain was further selected in two separate lines with one of the insecticides, followed by tests with the insecticide that the line had not been selected with. This indicated a concomitant rise of resistance to dieldrin in the fipronil‐selected line and vice versa. Repeated back‐crossing of the two lines with a susceptible strain and re‐selection with either dieldrin or fipronil gave evidence for the involvement of a single resistance mechanism to both insecticides. Permethrin resistance in both lines declined with selection for dieldrin or fipronil and confirms the absence of cross‐resistance between fipronil and pyrethroids. © 2001 Society of Chemical Industry 相似文献
16.
Factors involved in insecticide resistance were evaluated by using 14C-labeled methyl parathion and aldrin to compare rates of absorption and metabolism by Heliothis virescens (F.) larvae that were resistant (R) and susceptible (S) to methyl parathion. Tests with third-stage R and S larvae suggested that the rate of insecticide absorption from the cuticular surface was not a major resistance factor. Further evidence for this assumption was demonstrated by the resistance of R larvae to injected and orally administered doses of methyl parathion. Smaller amounts of unmetabolized methyl parathion and aldrin were recovered from S larvae, an indication that differences in metabolism were probably related to the resistance. 相似文献
17.
Keiji Tanaka Minoru Nakajima Norio Kurihara 《Pesticide biochemistry and physiology》1981,16(2):149-157
The factors which cause lindane resistance in the Third Yumenoshima strain, a strain of house flies highly resistant to insecticides, were studied using hexadeuterated lindane. Hexadeuterated lindane has the same physicochemical properties as lindane, but the former is much less biodegradable than the latter. The LD50 ratio of lindane to hexadeuterated lindane in this strain, deuterium isotope effect on LD50 values, was larger than that in SNAIDM, a susceptible (nonresistant) strain. The penetration rates of labeled and nonlabeled lindane through the insect cuticle were about the same for both strains. Thus, penetration rate does not cause resistance. The metabolic degradation of lindane in the resistant strain in vivo occurred much faster than in the susceptible strain. This was also the case for lindane degradation processes in vitro such as microsomal oxidation and glutathione conjugation. In both strains, significant isotope effects were observed in the degradation rates in vitro of labeled and nonlabeled lindane. Therefore, principal biodegradation and detoxication pathways should include reactions which cleave the CH bonds. When the much less biodegradable d6 counterpart of lindane was applied to both strains, the susceptible strain became much more highly intoxicated than the other within 20 to 30 min. This indicates that a combination of both greater degradability and probably lower sensitivity at the action site are the main factors underlying resistance in the Third Yumenoshima strain. 相似文献
18.
After feeding 2,4-D or atrazine in a diet to southern armyworm (Spodoptera eridania Cram.) larvae for three days, the effect on total content and activities of cytochrome P450 and on insecticide toxicity were determined. Both 2,4-D and atrazine induced cytochrome P450-catalyzed aldrin epoxidation (AE) and methoxyresorufin O-demethylatin (MROD). The 2,4-D was a more potent inducer for total cytochrome P450 content, whereas atrazine disproportionately increased AE. Both compounds increased MROD significantly. The apparent kinetic characteristics of AE indicates that 2,4-D and atrazine induced similar P450 isozymes (Km 8.78 and 7.80 μM, respectively), which may differ from the constitutive isozyme (Km 3.14 μM). The 2,4-D-induced cytochrome P450 contributed to decreased carbaryl and permethrin toxicity, whereas the atrazine-induced cytochrome P450 caused decreased parathion and permethrin toxicity. The carbaryl toxicity correlated directly with 2,4-D-induced total P450 content and activities but not with atrazine-induced changes. The 2,4-D and atrazine also induced nonspecific esterase activity which may contribute to permethrin detoxification. 相似文献
19.
The penetration and metabolism of 2 - isopropoxyphenyl N-methyl-N-(2-methyl-4-tert - butylphenylsulfenyl)carbamate or sulfenyl-propoxur was examined in the house fly and honeybee. Reduced penetration was found to be a factor contributing to the lower toxicity of sulfenyl-propoxur to the honeybee. Honeybees and house flies metabolized sulfenyl-propoxur qualitatively in a similar manner. Quantitatively, larger amounts of propoxur were found in the house fly than in the honeybee soon after treatment with sulfenyl-propoxur. The slower rate of conversion of sulfenyl-propoxur to propoxur was considered as another factor responsible for the lower toxicity of the sulfenylated derivative to bees. The high susceptibility of bees to propoxur was related to high internal amounts of unchanged propoxur found soon after treatment. 相似文献
20.
The penetration of insecticides into houseflies, with and without the factor that delays penetration, was studied by measuring the amounts of the insecticides on the surface of the flies at intervals after treatment. The factor slowed the entry of all the insecticides tested, but its effect depended on the dose, and had little or no effect when the dose applied was big (20 μmUg/fiy). Penetration in all strains, susceptible and resistant, increased but not proportionally to the size of the dose. The rate insecticide was lost from the surface slowed with time and increasing age of the insects. It was faster in males than females, and was always faster in flies without the penetration factor. The differences in penetration between the flies with and without the factor was less with n-dodecane as solvent than with acetone. With all strains, rate of loss from the surface was slowest with dieldrin. Diazinon, parathion and chlorthion-ethyl were lost at about the same rate; diazoxon penetrated fastest. 相似文献