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1.
Hexachlorocyclohexane (HCH) is a highly recalcitrant organochlorine insecticide known for its chronic toxicity. In spite of many isolated studies a clear mechanism of cytotoxic action of HCH and the structure–toxicity relationship of its isomers is not well understood. We have investigated the toxicity of HCH isomers and its mechanism in Ehrlich Ascites tumor (EAT) cells. Our studies show differential cytotoxicity of HCH isomers (α, β, γ, and δ), δ isomer being most toxic and β the least. HCH-induced cell death was associated with induction of reactive oxygen species (ROS) formation, lipid peroxidation (LPO), and depletion of glutathione (GSH). The increase in oxidative stress was linked with increased NAD(P)H oxidase activity. HCH inhibited Na+,K+-ATPase, which could be involved in raising the intracellular calcium and increased Ca2+,Mg2+-ATPase activity. HCH lead to apoptotic as well as necrotic cell death as it was marked by increased caspase-3 activity and lactate dehydrogenase (LDH) leakage, respectively. Based on the results it is concluded that the HCH isomers inflict differential cytotoxicity which was highest by δ and lowest by β. Further, this study demonstrates for the first time a clear link between Na+,K+-ATPase, i[Ca2+] level, and oxidative stress in HCH-induced cytotoxicity. 相似文献
2.
Birgit Geueke Nidhi Garg Sneha Ghosh Thomas Fleischmann Christof Holliger Rup Lal Hans‐Peter E. Kohler 《Environmental microbiology》2013,15(4):1040-1049
Although the production and use of technical hexachlorocyclohexane (HCH) and lindane (the purified insecticidal isomer γ‐HCH) are prohibited in most countries, residual concentrations still constitute an immense environmental burden. Many studies describe the mineralization of γ‐HCH by bacterial strains under aerobic conditions. However, the metabolic fate of the other HCH isomers is not well known. In this study, we investigated the transformation of α‐, β‐, γ‐, δ‐, ε‐HCH, and a heptachlorocyclohexane isomer in the presence of varying ratios of the two enzymes that initiate γ‐HCH degradation, a dehydrochlorinase (LinA) and a haloalkane dehalogenase (LinB). Each substrate yielded a unique metabolic profile that was strongly dependent on the enzyme ratio. Comparison of these results to those of in vivo experiments with different bacterial isolates showed that HCH transformation in the tested strains was highly optimized towards productive metabolism of γ‐HCH and that under these conditions other HCH‐isomers were metabolized to mixtures of dehydrochlorinated and hydroxylated side‐products. In view of these results, bioremediation efforts need very careful planning and toxicities of accumulating metabolites need to be evaluated. 相似文献
3.
A number of different depressant and convulsant agents have been shown to alter accumulation of cerebellar cyclic GMP. Since the different hexachlorocyclohexane (HCH) isomers elicit different pharmacological responses in mammals, we examined their effects on the accumulation of cerebellar cyclic GMP. Mice received one of the HCH isomers and were sacrificed for determination of cyclic GMP concentrations one hour later. Gamma-HCH increased cyclic GMP while alpha and delta-HCH decreased it. In addition, alpha and delta-HCH prevented the increase in cyclic GMP due to the gamma isomer. Picrotoxin increased cyclic GMP in a manner similar to that of gamma-HCH while strychnine produced only a small increase. All three HCH isomers inhibited the binding of 3H-TBOB (a ligand for the GABA-A-receptor linked chloride channel) in mouse cerebellum. It is concluded that the different HCH isomers can have different effects on cerebellar cyclic GMP accumulation and that these effects may be mediated through actions at the GABA-A receptor linked chloride channel. 相似文献
4.
Pooja Sharma Swati Jindal Kiran Bala Kirti Kumari Neha Niharika Jasvinder Kaur Gunjan Pandey Rinku Pandey Robyn J. Russell John G. Oakeshott Rup Lal 《Biodegradation》2014,25(2):179-187
Two distinct microbial dehalogenases are involved in the first steps of degradation of hexachlorocyclohexane (HCH) isomers. The enzymes, LinA and LinB, catalyze dehydrochlorination and dechlorination reactions of HCH respectively, each with distinct isomer specificities. The two enzymes hold great promise for use in the bioremediation of HCH residues in contaminated soils, although their kinetics and isomer specificities are currently limiting. Here we report the functional screening of a library of 700 LinA and LinB clones generated from soil DNA for improved dechlorination activity by means of a high throughput colorimetric assay. The assay relies upon visual colour change of phenol red in an aqueous medium, due to the pH drop associated with the dechlorination reactions. The assay is performed in a microplate format using intact cells, making it quick and simple to perform and it has high sensitivity, dynamic range and reproducibility. The method has been validated with quantitative gas chromatographic analysis of promising clones, revealing some novel variants of both enzymes with superior HCH degrading activities. Some sphingomonad isolates with potentially superior activities were also identified. 相似文献
5.
Kaoru Sota Takehiro Amano Makoto Aida Akifumi Hayashi Ichiro Tanaka 《Bioscience, biotechnology, and biochemistry》2013,77(5):1019-1025
As a simplified model of natural pyrethrins, trans-2,5-hexadien-l-yl chrysanthemate (V), and its 2- or 3-methyl substituted homologues (III and IV), were prepared and tested for insecticidal activities against houseflies. All these compounds retained sufficient insect toxicity to illustrate an interesting relationships between chemical structure and insecticidal activity.The cis isomer (XII) of compound V and two positional isomers, 2-methylene-4-penten-l-yl and 1,5-hexadien-3-yl chrysanthemates (XIII and XIV), were also synthesized. Of these isomers, XIII was very slightly active, but the other isomers (XII and XIV) were completely ineffective.On the other hand, the insecticidal activity of 5-hexen-2-yn-l-yl ester (XV), en-yne analogue of V, was almost the same as that of V. 相似文献
6.
Biodegradation of hexachlorocyclohexane (HCH) by microorganisms 总被引:12,自引:2,他引:12
The organochlorine pesticide Lindane is the -isomer of hexachlorocyclohexane (HCH). Technical grade Lindane contains a mixture of HCH isomers which include not only -HCH, but also large amounts of predominantly -, - and -HCH. The physical properties and persistence of each isomer differ because of the different chlorine atom orientations on each molecule (axial or equatorial). However, all four isomers are considered toxic and recalcitrant worldwide pollutants. Biodegradation of HCH has been studied in soil, slurry and culture media but very little information exists on in situ bioremediation of the different isomers including Lindane itself, at full scale. Several soil microorganisms capable of degrading, and utilizing HCH as a carbon source, have been reported. In selected bacterial strains, the genes encoding the enzymes involved in the initial degradation of Lindane have been cloned, sequenced, expressed and the gene products characterized. HCH is biodegradable under both oxic and anoxic conditions, although mineralization is generally observed only in oxic systems. As is found for most organic compounds, HCH degradation in soil occurs at moderate temperatures and at near neutral pH. HCH biodegradation in soil has been reported at both low and high (saturated) moisture contents. Soil texture and organic matter appear to influence degradation presumably by sorption mechanisms and impact on moisture retention, bacterial growth and pH. Most studies report on the biodegradation of relatively low ( 500 mg/kg) concentrations of HCH in soil. Information on the effects of inorganic nutrients, organic carbon sources or other soil amendments is scattered and inconclusive. More in-depth assessments of amendment effects and evaluation of bioremediation protocols, on a large scale, using soil with high HCH concentrations, are needed. 相似文献
7.
MARK ROWLAND 《Medical and veterinary entomology》1990,4(4):397-404
The activity and resting behaviour of resistant and susceptible Anopheles stephensi Liston were recorded in acoustic actograph chambers lined with residual deposits of malathion, dieldrin or gamma HCH. In gamma HCH-treated flight chambers, SS and RS mosquitoes became active only after picking up lethal doses of insecticide, which explains why few SS and RS mosquitoes survive release into gamma HCH-treated experimental huts. Similar results were obtained in flight chambers treated with dieldrin; however, more mosquitoes would be expected to survive dieldrin under field conditions because resistance to this insecticide is greater than to gamma HCH. Mosquitoes in contact with malathion showed a three-phase activity pattern: an initial active phase, an inactive phase, and hyper-activity/convulsions. Initial activity or irritability was especially pronounced in SS and RS but absent in RR mosquitoes. Whether or not irritability would protect RS mosquitoes from malathion would probably depend on the ratio of sprayed to unsprayed surfaces in treated huts. 相似文献
8.
Feng JY Johnson AA Johnson KA Anderson KS 《The Journal of biological chemistry》2001,276(26):23832-23837
Several of the nucleoside analogs used in the treatment of AIDS exhibit a delayed clinical toxicity limiting their usefulness. The toxicity of nucleoside analogs may be related to their effects on the human mitochondrial DNA polymerase (Pol gamma), the polymerase responsible for mitochondrial DNA replication. Among the AIDS drugs approved by the FDA for clinical use, two are modified cytosine analogs, Zalcitabine (2',3'-dideoxycytidine (ddC)) and Lamivudine (beta-d-(+)-2',3'-dideoxy-3'-thiacytidine ((-)3TC])). (-)3TC is the only analog containing an unnatural l(-) nucleoside configuration and is well tolerated by patients even after long term administration. In cell culture (-)3TC is less toxic than its d(+) isomer, (+)3TC, containing the natural nucleoside configuration, and both are considerably less toxic than ddC. We have investigated the mechanistic basis for the differential toxicity of these three cytosine analogs by comparing the effects of dideoxy-CTP), (+)3TC-triphosphate (TP), and (-)3TC-TP on the polymerase and exonuclease activities of recombinant human Pol gamma. This analysis reveals that Pol gamma incorporates (-)3TC-triphosphate 16-fold less efficiently than the corresponding (+)isomer and 1140-fold less efficiently than dideoxy-CTP, showing a good correlation between incorporation rate and toxicity. The rates of excision of the incorporated analogs from the chain-terminated 3'-end of the DNA primer by the 3'-5'-exonuclease activity of Pol gamma were similar (0.01 s(-)1) for both 3TC analogs. In marked contrast, the rate of exonuclease removal of a ddC chain-terminated DNA occurs at least 2 orders of magnitude slower, suggesting that the failure of the exonuclease to remove ddC may play a major role in its greater toxicity. This study demonstrates that direct analysis of the mitochondrial DNA polymerase structure/function relationships may provide valuable insights leading to the design of less toxic inhibitors. 相似文献
9.
T S Dikshith R B Raizada M K Srivastava S N Kumar R A Kaushal R P Singh K P Gupta K S Lakshmi 《Indian journal of experimental biology》1989,27(3):252-257
Application of HCH (25 mg/kg) on dorsal, ventral and thigh regions of the skin of male rabbits resulted in poisoning and mortality of animals. Morphological changes in skin, liver, kidney, testes and cerebellum together with highly significant alterations in serum and liver enzymatic activity and residue in blood suggested that absorption of HCH and its toxicity could be severe when the pesticide comes in contact with the skin of thigh region of body. 相似文献
10.
11.
《Journal of Asia》2023,26(4):102127
Frankliniella occidentalis (Pergande), Myzus persicae (Sulzer), Plutella xylostella (L), and Spodoptera exigua (Hübner) are notorious agricultural insect pests worldwide. Due to the rapid development of resistance to the conventional insecticides, the number of available insecticides might be reduced in a near future, and botanical insecticides can be considered as one of the potential candidates to solve this problem. In the present study, test formulations were prepared using plant essential oils and extracts as main active ingredients, and their insecticidal activity and phytotoxicity were examined. Among the combinations tested, two oil-in-water formulations of NRS-13 containing thyme white oil and NRS-24 containing basil and rosemary oils were selected based on their notable insecticidal activity and low phytotoxicity. Chemical analyses on the active essential oils, the quantitative analysis of the major components in the formulations, insecticidal activities under pot and field conditions, their acute toxicity on mammals, and ecotoxicity on fish were also examined. The NRS-13 (BaechooSaferTM) and NRS-24 (JindiOutTM) formulations showed species-specific insecticidal activity against P. xylostella and M. persicae, respectively. In addition, both formulations produced low acute oral and dermal toxicity, skin and eye irritation, and fish toxicities, which suggests those formulations based on essential oils could be considered as insecticides for pest control in small-scale environments in organic farming. 相似文献
12.
A. STRINGER 《The Annals of applied biology》1956,44(3):506-510
Although the insecticidal effectiveness of a compound is dependent on many factors, such as Solubilities and detoxification, there appear to be distinct relationships between chemical structure and insecticidal activity. The insecticidal activity of paraoxon was significantly greater to the adult males of Locusta migratoria migratorioides than that of all other nitrophenyl-phosphorus compounds tested. This may be attributed to the direct action of the compound, involving no change from inactive to active form in vivo , and also to a better translocation of the compound from the point of application to the site of action. The toxicity of injected paraoxon was of the same order as that topically applied. Parathion, its isomers, and ethyl p-nitrophenyl phenyl phosphonothionate (EPN) were approximately equivalent, whereas malathion, although relatively low in toxicity, with an ED50 , of 29 μg./insect, was still a reasonably effective insecticide. Methyl, ethyl and iso- propyl esters were effective in that order of toxicity. Substitution of other alkoxy or aryloxy groups resulted in loss of activity. 相似文献
13.
Surface biophysics of the surface monolayer theory is incompatible with regional lung function. 总被引:2,自引:2,他引:0
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The surface monolayer theory of Clements was tested on open surface films of calf lung surfactant extract in a leak-free vertical film surface balance in which alveolar area (A) changes in each lung zone were simulated in accordance with the theory. We found that: 1) physiologically necessary low surface tension (gamma), < 4 dyn/cm, was sustained only by continuous film compression ("expiration"); 2) compression from A equivalent to total lung capacity to functional residual capacity produced fleeting gamma reduction in all zones and quick reversal to high gamma with A changes that simulated tidal volume (VT) breathing at both 14 (adult) and 40 (neonatal) cpm; 3) phase differences between gamma and A axes of VT loops that indicate mixed surface film composition may be attributable to film inertia and viscoelasticity; 4) estimated alveolar retraction pressure due to gamma (P gamma) exceeds "net" transpulmonary pressure, i.e., favors alveolar collapse, under virtually all conditions of the theory in all zones; 5) return to transient, fleeting low gamma in successive VT cycles was determined by the inherent difference in compression and decompression rates, which results in exhaustion of available A in very few cycles; 6) the "sigh", which restores stable low gamma according to the theory, actually produced unstable high gamma during virtually all phases of the maneuver. In contrast, closed bubble films of the surfactant were structurally stable and produce stable near 0 gamma and P gamma. 相似文献
14.
Kagabu S Kiriyama K Nishiwaki H Kumamoto Y Tada T Nishimura K 《Bioscience, biotechnology, and biochemistry》2003,67(5):980-988
The asymmetric chloronicotinyl insecticide, 1-[1-(6-chloro-3-pyridyl)ethyl]-2-nitroiminoimidazolidine, was prepared, and the absolute configurations of the enantiomers were determined by an X-ray analysis. The insecticidal activity against the housefly measured with metabolic inhibitors showed the (S) enantiomer to be slightly more active than the (R) isomer. Electrophysiological measurements on the American cockroach central nerve cord showed the compounds to elicite the impulses and subsequently blocked them. The neuroblocking potency of the (S) isomer was 5.9 microM, while that of the (R) isomer was as high as 73 microM. The molar concentrations required for 50% inhibition of the specific binding of [3H]imidacloprid to the housefly head membrane preparation were respectively 0.19 microM and 0.95 microM for the (S) and (R) isomers. This enatioselectivity ratio was smaller than 35 for nicotine isomers but greater than 2 for epibatidine isomers. 相似文献
15.
Aim: To screen and identify bacteria from contaminated soil samples which can degrade hexachlorocyclohexane (HCH)‐isomers based on dechlorinase enzyme activity and characterize genes and metabolites. Methods and Results: Dechlorinase activity assays were used to screen bacteria from contaminated soil samples for HCH‐degrading activity. A bacterium able to grow on α‐, β‐, γ‐ and δ‐HCH as the sole carbon and energy source was identified. This bacterium was a novel species belonging to the Sphingomonas and harbour linABCDE genes similar to those found in other HCH degraders. γ‐Pentachlorocyclohexene 1,2,4‐trichlorobenzene and chlorohydroquinone were identified as metabolites. Conclusions: The study demonstrates that HCH‐degrading bacteria can be identified from large environmental sample‐based dehalogenase enzyme assay. This kind of screening is more advantageous compared to selective enrichment as it is specific and rapid and can be performed in a high‐throughput manner to screen bacteria for chlorinated compounds. Significance and Impact of the Study: The chlorinated pesticide HCH is a persistent and toxic environmental pollutant which needs to be remediated. Isolation of diverse bacterial species capable of degrading all the isomers of HCH will help in large‐scale bioremediation in various parts of the world. 相似文献
16.
【目的】探讨甲酸乙酯与异硫氰酸甲酯混用对菜豆象成虫的熏蒸效果及防治最优化配方。【方法】采用广口瓶密闭熏蒸法,在测得甲酸乙酯、异硫氰酸甲酯LC50值的基础上,应用二因子二次通用旋转回归组合设计,根据拉格朗日求极值原理求取防治效果与经济效益均达到要求的最优化配方。【结果】2种药剂对菜豆象成虫的毒力存在较大的差异,其中异硫氰酸甲酯的杀虫效果较强(LC50值为0.667 mg·L-1),甲酸乙酯的杀虫效果次之(LC50值为20.59μL·L-1);通过二因子二次通用旋转回归组合设计可得一个二次多项式,再根据优化目标函数和约束函数,求得混配液中甲酸乙酯的用药量为102.702μL,异硫氰酸甲酯的用药量为3.0263 mg。【结论】当甲酸乙酯与异硫氰酸甲酯比例为33.94∶1时,可获得最佳经济效益,且杀虫效果最佳。 相似文献
17.
Effects of lindane on steroidogenesis and steroidogenic acute regulatory protein expression 总被引:8,自引:0,他引:8
Lindane, the gamma isomer of hexachlorocyclohexane (HCH), is one of the oldest synthetic pesticides still in use worldwide. Numerous reports have shown that this pesticide adversely affects reproductive function in animals. Although the pathogenesis of reproductive dysfunction is not yet fully understood, recent reports indicate that lindane can directly inhibit adrenal and gonadal steroidogenesis. Because Leydig cells play a pivotal role in male reproductive function through the production of testosterone, the mouse MA-10 Leydig tumor cell line was used to assess the potential effects of gamma-HCH and its isomers, alpha-HCH and delta-HCH, on steroid production, steroidogenic enzyme expression and activity, and steroidogenic acute regulatory (StAR) protein expression. StAR mediates the rate-limiting and acutely regulated step in hormone-stimulated steroidogenesis, the intramitochondrial transfer of cholesterol to the P450(scc) enzyme. Our studies demonstrate that alpha-, delta-, and gamma-HCH inhibited dibutyryl ([Bu](2)) cAMP-stimulated progesterone production in MA-10 cells in a dosage-dependent manner without affecting general protein synthesis; and protein kinase A or steroidogenic enzyme expression, activity, or both. In contrast, each of these isomers dramatically reduced (Bu)(2)cAMP-stimulated StAR protein levels. Therefore, our results are consistent with the hypothesis that alpha-, delta-, and gamma-HCH inhibited steroidogenesis by reducing StAR protein expression, an action that may contribute to the pathogenesis of lindane-induced reproductive dysfunction. 相似文献
18.
Conformational analysis, by the method of atom-atomic potentials, has been carried out for five tripeptides containing gamma-glutamyl bonds and having general formula Glu(gamma)-X-Gly. The spatial structures have been determined and the changes arising on varying the second residue have been analyzed. A comparison of possible conformations and biological activity in respect to a number of enzymes allows to conceive what structural features of these compounds are important for the substrate specificity of the enzymes. In particular, the active site topography has been surmised for glutathione synthetase (EC 6.3.2.3) and gamma-glutamyltranspeptidase (EC 2.3.2.2). The glutathione thiol group has been found to be exposed in all possible conformations that explains its accessibility for various reagents. 相似文献
19.
P Ravinder K Srinivasan R Radhakrishnamurty 《Indian journal of experimental biology》1989,27(3):248-251
Dietary hexachlorocyclohexane (HCH) and gamma-isomer of HCH produced significant increase in liver weights of mice. Elevated levels of alanine and aspartate aminotransferases and of alkaline phosphatase in the blood of these animals suggested hepatotoxicity. Hepatic soluble enzymes--aspartate aminotransferase and lactate dehydrogenase--were markedly lowered. Among the hepatic lysosomal enzymes, acid phosphatase and acid cathepsin were increased in the experimental animals. Hepatic glucose-6-phosphatase was lowered by HCH while aldolase activity was increased. Hydrolytic enzymes in small intestine, viz., disaccharidases, lipase, amylase, dipeptidase and phosphatases, were also affected by dietary HCH and gamma-HCH. The results suggested cellular toxicity in hepatocytes of HCH and gamma-HCH fed animals, and also interference in gastrointestinal absorption. 相似文献
20.
Raina V Suar M Singh A Prakash O Dadhwal M Gupta SK Dogra C Lawlor K Lal S van der Meer JR Holliger C Lal R 《Biodegradation》2008,19(1):27-40
Soil pollution with hexachlorocyclohexane (HCH) has caused serious environmental problems. Here we describe the targeted degradation
of all HCH isomers by applying the aerobic bacterium Sphingobium indicum B90A. In particular, we examined possibilities for large-scale cultivation of strain B90A, tested immobilization, storage
and inoculation procedures, and determined the survival and HCH-degradation activity of inoculated cells in soil. Optimal
growth of strain B90A was achieved in glucose-containing mineral medium and up to 65% culturability could be maintained after
60 days storage at 30°C by mixing cells with sterile dry corncob powder. B90A biomass produced in water supplemented with
sugarcane molasses and immobilized on corncob powder retained 15–20% culturability after 30 days storage at 30°C, whereas
full culturability was maintained when cells were stored frozen at −20°C. On the contrary, cells stored on corncob degraded
γ-HCH faster than those that had been stored frozen, with between 15 and 85% of γ-HCH disappearance in microcosms within 20 h
at 30°C. Soil microcosm tests at 25°C confirmed complete mineralization of [14C]-γ-HCH by corncob-immobilized strain B90A. Experiments conducted in small pits and at an HCH-contaminated agricultural site
resulted in between 85 and 95% HCH degradation by strain B90A applied via corncob, depending on the type of HCH isomer and
even at residual HCH concentrations. Up to 20% of the inoculated B90A cells survived under field conditions after 8 days and
could be traced among other soil microorganisms by a combination of natural antibiotic resistance properties, unique pigmentation
and PCR amplification of the linA genes. Neither the addition of corncob nor of corncob immobilized B90A did measurably change the microbial community structure
as determined by T-RFLP analysis. Overall, these results indicate that on-site aerobic bioremediation of HCH exploiting the
biodegradation activity of S. indicum B90A cells stored on corncob powder is a promising technology. 相似文献