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1.
Escherichia coli endotoxin instilled intranasally into mice and rats caused a severe pulmonary oedema associated with progressive increases in lung weights of up to 30% within 2 days. When mice were injected with DDT (20 mg/kg) 20 and 2 hr prior to the administration of endotoxin the animals were found to be tolerant to the endotoxin. The inflammatory oedema induced by endotoxin is caused by release of lung histamine, and as DDT injections also lowered histamine content in the lungs, the protective effect of DDT against the oedema induced by endotoxin appears to be due to its prior depletion of the lung histamine stores. An opposite effect, increased and accelerated inflammation, was observed by chronic exposure of rats to dietary DDT (150 ppm) fed for 36 days. The long-term feeding of DDT is known to cause adaptations in many physiological systems. One of these may be increased histamine synthesis and subsequently increased severity of histamine mediated reactions. 相似文献
2.
Release of histamine from mast cells by DDT was demonstrated by incubating guinea pig mesentery explants with 20 μg DDT/ml in vitro for various periods up to 2 hr. The histamine content of mesentery explants showed progressive decreases concomitant with increasing histamine values in the incubation medium. In the mesentery explants the histamine content decreased to 31% of the original content within 45 min and then increased to 113% at the 120-min interval. As the total amount of histamine released into the medium during the 2 hr of incubation with DDT was twice the original amount of histamine in the tissues, it is evident that the initial release of histamine by DDT stimulates its resynthesis in the mast cells. 相似文献
3.
Earlier communications from this laboratory have shown that DDT inhibited oligomycin-sensitive Mg2+-ATPase (EC 3.6.1.3) but that its active component, F1, was not affected. In the present investigation evidence has been obtained to determine the nature of the requirements for DDT sensitivity. The results showed that DDT sensitivity was conferred to F1 from pig heart mitochondrial preparations when it was bound to F0 from the same preparation. The F1 from house fly (Musca domestica L) thorax was able to bind to F0 from pig heart. This combination showed similar sensitivity to that of the original F1-F0 combination from pig heart mitochondria. However, when F1 from pig heart mitochondria was incorporated into F0 depleted in oligomycin sensitivity-conferring protein (OSCP) from the same source, the resulting ATPase activity was insensitive to DDT. Addition of crude (50–200 μg) or purified (5–20 μg) OSCP in the above preparation restored DDT sensitivity. Presence of dioleyl or dipalmitoyl phosphatidyl choline or Triton X-100 in the reaction medium antagonized the DDT inhibitions. Depletion of phospholipids from submitochondrial membrane preparations (SMP) decreased ATPase activity. Addition of dioleyl or soybean phosphatidyl choline to this lipid-depleted preparation restored DDT sensitivity. Evidence presented suggests that DDT acted on F1 in association with one or more membrane components and that OSCP and phospholipid were essential for DDT sensitivity. 相似文献
4.
Ellen M. Burnett 《Pest management science》1970,1(2):70-72
Cattle were treated thrice weekly for 12 weeks with simulated backrubbers impregnated with 1% solutions of pesticides in mineral oils. Both coumaphos and methoxychlor applied in S.A.E. 50 oil induced maximum residues of 0–21 ppm in omental fat after 12 weeks treatment. Application of DDT in S.A.E. 50 oil or in used crankcase oil induced residues of 0·5–7 ppm DDT in omental fat after 12 weeks treatment. Where diesel fuel oil was the vehicle, DDT residues in omental fat were in the range 17–26ppm. 相似文献
5.
Amounts of DDT and its breakdown products were determined in soil in an apple orchard in Herefordshire. Samples were taken for a number of years (1972–79) after use of the insecticide in the orchard had ceased in 1969. The results were compared with those obtained in an investigation of the same orchard in 1968. From 1968 to 1979, soil residues of pp′-DDT, p′--DDT and pp′--TDE decreased gradually whereas those of pp′--DDE increased, and there were linear relationships between log (concentration) and time. The calculated time for 50% decrease in concentration (Dt50) was 11.7 years for pp′--DDT, 3.3 years for pp′--TDE and 7.1 years for op′--DDT; the time for doubling the concentration for pp′--DDE was 9.1 years. Regression analysis on the two major components (pp′--DDT+pp′--DDE) indicated that the total amount (2.7 mg kg?1) was not decreasing with time. It was concluded that during a post-spray era, the breakdown of pp′--DDT to pp′--DDE was a significant feature of the persistence of DDT, and that, in contrast to the findings of other workers who sampled when DDT was being used, there were no losses by volatilisation. There was an exponential decrease in the amount of DDT residues with increasing soil depth and approximately 90% was found in the top 10 cm of the undisturbed soil profile. 相似文献
6.
Muscle, liver, brain, and abdominal body fat samples of goats, buffalo, and chickens, all common meat sources in India, were analyzed by gas-liquid chromatography (GLC) for residues of DDT and benzene hexachloride (BHC). A few samples of goat and buffalo bone marrow were also included. Relatively high residue levels were found in body fat and bone marrow compared with other tissues. DDT and BHC residue levels were highest in chicken body fat, averaging 4.157 ppm sigma DDT and 3.879 ppm BHC. DDT content was much higher in goat and buffalo bone marrow than in the corresponding body fat. DDT levels in brain samples were highest (0.138 ppm) in buffalo. p,p'-TDE levels were higher than p,p'-DDE levels in buffalo; overall DDT levels were lowest in goats. BHC residues were generally low in buffalo; alpha-BHC accounted for most BHC residues in brain tissues. Greater accumulations of DDT and BHC were found in leg muscles than in breast muscles of chickens. 相似文献
7.
The effect of DDT (2,2-bis-(p-chlorophenyl)-1,1,1-trichloroethane) on carbon assimilation of a green alga, Selanastrum capricormutum was studied. DDT at concentrations between 3.6 and 36 ppb was inhibitory to the photosynthetic CO2 fixation (ethanol-soluble and/or ethanol-insoluble) and the longer the exposure to DDT, the greater the inhibition. Kinetic studies of photosynthetic CO2 fixation indicated that DDT stimulated the incorporation of carbon-14 into glycolic acid, a major compound of photorespiration and caused the concomittant suppression of flow of carbon-14 into aspartic acid, a major component of the C4-dicarboxylic acid pathway. The shift from an efficient pathway into a nonefficient pathway by DDT was interpreted to be through interruption of cyclic photophosphorylation. 相似文献
8.
Selection with pp'-DDT was applied to fourth-stage larvae of Aedes aegypti along four lines, starting with larvae of the F2 generation from crosses between a susceptible strain and each of four resistant strains (two of Trinidad origin and two of Bangkok origin). Larval resistance increased substantially along each line but there was little or no change in the percentage breakdown of DDT to 1,1-dichloro-2,2-bis(4-chloro-phenyl)ethylene (pp'-DDE) in vivo and in no line were these two variables significantly correlated. Percentage breakdown was generally higher at 10 mg than at 50 mg litre?1. DDT uptake (defined as content of DDT+pp'-DDE) was generally higher after exposure to 50 mg than to 10 mg litre?1. It increased significantly with selection in the TE×NS line; it remained unchanged in the T8 × NS line; and in the other two lines (BSJ × NS and B51 × NS), it increased initially but dropped as selection progressed, the reduction being highly significant in the second of these lines. The amount of internal residual (unmetabolised) DDT tolerated by larvae of the TE × NS line also increased significantly with resistance. The levels in the other lines followed the pattern of uptake, remaining steady in T8 × NS despite the increase in survival, rising at first and then declining in the two Bangkok lines. Thus selection produced a higher tolerance to internal unmetabolised DDT in the two Trinidad lines but led ultimately to a lower content of DDT+pp'-DDE in the two Bangkok lines. The reasons for this behaviour are discussed. 相似文献
9.
A continuous steady-state assay procedure was used to investigate the effects of DDT and several analogs on the in vitro Mg2+-stimulated adenosinetriphosphatase of a trout brain mitochondrial fraction. Pharmacological dissection of the enzyme with oligomycin, dicyclohexyl-carbodiimide, and azide failed to yield a fraction specifically sensitive to the organochlorines. At 25°C, low doses of DDT (≤1.35 μmol/mg of protein) stimulated enzyme activity, while methoxychlor was stimulatory at all doses. Higher doses of DDT and of several analogs caused only 45.5% or less inhibition at 25°C, but inhibition increased at lower temperatures. The physiological significance of these effects is discussed. 相似文献
10.
Derek W. Gammon 《Pest management science》1978,9(2):95-104
Some effects of DDT on the cockroach nervous system have been correlated with poisoning symptoms, using free-walking cockroaches with implanted electrodes. Experiments at 16.5°C and 32°C used LD95 doses and at 25°C, an estimated LD95. DDT had excitant actions on each nerve studied; cercal afferent and efferent neurones, and abdominal interneurones. The effects on the central nervous system became more marked as temperature was reduced, despite the smaller quantity of DDT employed, but the excitant actions on the peripheral nervous system were not quantified. It is suggested that the effects of DDT on the cockroach nervous system could account for the negative temperature coefficient of toxicity of DDT. 相似文献
11.
Larvae of eight strains of Aedes aegypti were exposed to DDT and compared for resistance, DDT uptake, in-vivo breakdown of DDT and residual unmetabolised DDT. Resistance varied widely between strains, three being fully susceptible, two almost immune and three of intermediate resistance. Breakdown of DDT by dehydrochlorination to 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (pp'-DDE) occurred in all strains and was greater in the five resistant types, but there was no significant correlation between the extent of breakdown in the resistant strains and the level of resistance. Moreover the overall difference between susceptible and resistant strains disappeared when they were compared at a low, almost sublethal, concentration of DDT. Larvae of resistant strains carried a greater absolute quantity of unmetabolised DDT in the body and were able to tolerate levels of DDT that were lethal to susceptible larvae. However the two most resistant strains (T8 and B51) contained significantly less DDT plus pp'-DDE than strains of intermediate resistance (T30 and BSJ) from which they had been derived. Addition of the synergist chlorfenethol to DDT increased its knockdown effect on all resistant strains, suggesting that dehydrochlorination was a factor in resistance. Three strains, two DDT-resistant and one DDT-susceptible, were tested with 1,1-bis(4-ethoxyphenyl)-2,2-dimethylpropane (I), an insecticide that cannot be dehydrochlorinated. All the strains were relatively tolerant to it although the DDT-susceptible strains were less tolerant. Addition of the synergist sesamex decreased the level of tolerance to I in all strains which suggested that microsomal oxidation made some contribution to it. It is concluded that three factors contribute to larval DDT resistance in A. aegypti; (a) increased metabolism to pp'-DDE; (b) increased tolerance to unmetabolised internal DDT; and (c) reduced content of DDT+pp'-DDE (only in the most resistant strains and due either to reduced absorption or increased excretion). These factors are discussed in relation to known larval resistance genes RDDT1 and y. 相似文献
12.
Yehia A.I. Abdel-Aal 《Pesticide biochemistry and physiology》1983,20(1):115-123
A quantitative structure-activity relationship (QSAR) has been carried out for Phormia regina toxicity by a set of 24 p,p′-disubstituted analogs of DDT. The toxicity data are from the extensive studies of R. L. Metcalf. Preliminary examination of the data indicated that toxicity was parabolically related to molar refractivity, MR, of the ring substituents. This enabled parabolic regression to be evaluated. Multiple regression analysis relating toxicity and the substituent constants MR, Taft steric parameter (Es), hydrophobicity (π), and polar effect (σ) showed that MR dominated the regression equations. The implication of these physicochemical properties in the interaction of DDT analogs with the receptor site is discussed. 相似文献
13.
A continuous in vitro steady-state assay procedure was used to investigate the dependence of trout brain mitochondrial Mg2+-stimulated adenosinetriphosphatase specific activity on temperature and substrate concentration. The inhibition of enzyme activity by DDT was independent of substrate concentration. DDT and several analogs caused increases in the experimental activation energy and frequency factor of the enzyme-catalyzed reaction, which gave rise to a negative temperature coefficient of inhibition. It is suggested that DDT and other highly lipophilic compounds have the potential to allosterically affect membrane-bound enzymes by simply becoming a major lipoid component of the membranes. 相似文献
14.
DDT inhibits the ATPase activity of the intact eel electroplaque. At a concentration of 10?5M, DDT inhibited 46% of the total ATPase activity, and 10?4M DDT inhibited 62% of the total ATPase activity and 62% of the ouabain-sensitive ATPase activity. The latter concentration of DDT reduced the rate of Na efflux from intact electroplaques and slowed the rate of recovery of the membrane potential following a large depolarization produced by carbamylcholine application. Repetitive direct stimulation of the innervated membrane at 10 Hz during the application of 10?4M DDT produced a significant irreversible depolarization. Ouabain, 10?4M, produced similar effects. The possible role of the inhibition of active NaK transport in producing the symptoms of DDT poisoning is discussed. 相似文献
15.
Microsome fractions were prepared from liver homogenates of control rats and rats treated with DDT. The increased incorporation of [14C]phenylalanyl-tRNA into peptide when microsomes or ribosomes derived from DDT-treated rats were incubated with supernatant was due to factors in addition to increased endogenous mRNA. These factors were not related to the decreased activity of ribonuclease and increased activity of ribonuclease inhibitor, nor to the GTP and thiol sensitive inhibitor. The factors were partly removed from microsomes and completely removed from ribosomes by procedures using a 0.5 M KCl wash. Treatment of rats with polychlorinated biphenyls gave results similar to DDT. The 0.5 M KCl wash fraction from the control preparations contained factors inhibitory to protein synthesis in contrast to the wash fraction from the DDT preparations. 相似文献
16.
Agricultural uses of the insecticide DDT were cancelled by the U.S. Environmental Protection Agency December 31, 1972. However, the domestic use of DDT had begun to decline before this action. Beginning July 1969, residues of DDT and its metabolites were measured in human adipose tissue collected through an annual national survey. Levels of total DDT equivalent residues in human adipose have decreased slightly, but the frequencies of finding DDT or its metabolites have remained high. The most marked decline in residue concentration has been found in the youngest age group (0-14 years). Approximately 80 percent of the total DDT equivalent found in this survey was DDE. These data show that the reduction of the agricultural uses of DDT has decreased human exposure to and storage of this chemical. 相似文献
17.
The nature of target site or knockdown resistance (kdr) to DDT and pyrethroids was studied by investigating specific binding of [14C] DDT and [14C] cis-permethrin to the previously established membrane receptors from the heads of susceptible (sbo) and resistant (kdr) strains of the house fly, Musca domestica L. In vivo studies showed the heads from sbo flies bound two to three times more DDT than those from kdr flies at all doses tested. Reduced binding was also observed in kdr flies in in vitro [14C] DDT binding assays. Scatchard analysis indicated that kdr flies have the same affinity but fewer receptors per milligram protein in the CNS than sbo flies. Assays with [14C] cis-permethrin also showed binding was much reduced in kdr flies in comparison with sbo flies. Based on these results, the nature of the target site insensitivity of kdr flies may relate to their having a reduced number of receptors for the insecticides. 相似文献
18.
An insect water-soluble ATPase (IF1) was isolated from mitochondria of cockroach coxal muscle. It was homogenous as assessed by polyacrylamide gel electrophoresis and electron microscopy. It was found to be composed of five subunits with molecular weights of 70,000, 68,000, 53,000, 43,000, and 34,000. IF1 was cold labile and showed maximal activity at 47–50°C. Its ATPase activity was Mg+ dependent and was stimulated by DNP and p-hydroxy-mercuribenzoate. This activity was inhibited by sodium azide and guanidine-HCl, not inhibited by oligomycin, and only slightly inhibited at a relatively high level of DDT. The site of action of DDT is discussed in light of relative insensitivity of IF1 ATPase to DDT compared to the high sensitivity of particulate mitochondrial ATPase activity. 相似文献
19.
A Ca-ATPase highly sensitive to DDT has been found in peripheral nerves of lobster, Homarus americanus. The observed I50 for this Ca-ATPase toward DDT is on the order of 10?9M and has a low temperature quotien. The ATPase seems to work over a wide range of ATP concentrations. It is stimulated by Ca2+ (optimum 0.1 mM) and shows sensitivity to Na+ (optimum 20 mM) and K+ (optimum 20 mM) ions. The fact that it is highly sensitive to ruthenium red (I50 = 10 μM) suggests that the enzyme is a Ca-ATPase and not a Mg-ATPase. Furthermore the enzyme is not a CaMg-ATPase, since the presence of Mg2+ along with Ca2+ ion is not required for its activity. DDT is found to inhibit the process of Ca2+ binding in the axonic membrane only in the presence of ATP. The evidence suggests the important role of the Ca-ATPase in regulating Ca2+ concentrations in the membrane. The possible significance of DDT inhibition of the ATPase is discussed. 相似文献
20.
In this paper, a DSC and Raman study of hydrated multilamellar DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) and DMPE (1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine) liposomes in presence of increasing amounts of DDT is reported.The observed changes denote that DDT molecules interact with both phospholipids and that the interaction mainly involves the external part of the bilayer since the deep penetration into the hydrophobic core is prevented by the setting up of polar interactions between the three aliphatic C-Cl bonds of the trichloro group of DDT and the -N+(CH3)3 of DMPC or the -NH3+ groups of DMPE molecules.This behaviour was particularly evidenced in presence of DMPE, as the insertion of DDT molecules into the central part of the bilayer seems to be completely excluded.Moreover, in DMPE liposomes the overall structure of the bilayer changes to a well defined and structured ‘phase II’ in presence of even small DDT amounts. 相似文献