Phlorizin alleviates deltamethrin-induced oxidative stress in brine shrimp Artemia

Deltamethrin(DEL),a commonly used pyrethroid pesticide,results in higher reactive oxygen species(ROS)levels in aquatic animals,which consequently unbalance the redox state.Phlorizin(PHL)is a flavonoid and a natural product promising to prevent or reduce pesticide-induced oxidative stress.Artemia is a micro-crustacean widely used in marine hatcheries and an experimental aquatic organism for environmental toxicology research.This research aimed to evaluate the toxicity of DEL on Artemia and the antioxidative effect of PHL against the toxicity.Results show that 0.08-mg/mL PHL exerted its antioxidative effects on hatching percentage of the cysts in 24-h incubation and on body length and survival rate of Artemia in 12-d culture.After 12-d culture,12-,24-,and 36-h DEL exposure showed significant drops in SOD,CAT,and GSH-Px enzyme activities,and significant increases in ROS and malondialdehyde(MDA)levels in Artemia(P<0.05).On the contrary,0.08-mg/mL PHL application improved the enzyme activities and decreased the ROS and MDA levels(P<0.05).Moreover,0.08-mg/mL PHL significantly increased mRNA expression levels of Cu/Zn SOD,CAT,GST,HO-1,NQO1,and Nrf2,and decreased mRNA expression level of Keap1 in the DEL-exposed Artemia(P<0.05).Therefore,DEL is toxic to Artemia,while PHL alleviates DEL-induced oxidative damage by possibly regulating the Nrf2signaling pathway.This study provided a theoretical basis for PHL to reduce pesticide-induced toxicity in aquatic animals.

Studies on the Effects of Deltamethrin on Sodium Net Transport Through the in vivo Amphibian Skin

The action of micromolar concentrations of Deltamethrin on sodium net transport through the in vivo skin of the South American toad Bufo arenarum was studied. The effect of pure ethanolic insecticide solutions and commercial formulations when applied on the mucosal surface was assayed. Deltamethrin provoked a concentration-independent inhibition; the highest inhibition was found at the lowest concentrations. At highest concentrations of the insecticide the J Na was not

Susceptibility to temephos,permethrin and deltamethrin of Aedes aegypti(Diptera:Culicidae) from Muang district,Phitsanulok Province,Thailand

Objective:To investigate the susceptibility to temephos.permethrin and deltamethrin of Aedes aegypti Ae.aegypti),collected from areas with high incidence of dengue hemorrhagic fever cases in Phitsanulok Province.Thailand.Methods:The F1 progenies of Ae.aegypti colony,originated from five sub-districts including Aranyik.Hua Ro,Nai Muang.Ban Krang and Tha Pho,were used in the bioassays following the procedures of World Heath Organization.For larval bioassay.the late third or early fourth-instar lanae were tested with different concentrations of temephos.For adult bioassay.the females were exposed to 0.75%permethrin or 0.05%deltamethrin.LC_(50)value and mortality rate were analyzed to compare the insecticide susceptibility of the larvae and the adults in each area,respectively.Results:The LC_(50) value of temephos for the larvae from Aranyik.Hua Ro.Nai Muang,Ban Krang and Tha Pho sub-districts was 0.017.0.017.0.026.0.061.and 0.113 ppm,respectively.For permethrin,the highest morlalitv rate(86.84%) was found in the mosquitoes from Aranyik but the others were more resistant with the lower morlality rates(16.00-42.67%).The adult morlality rates after exposing to dellaiiielhrin were higher(82.34-98.67%) in all areas.Conclusions:Ae.acgypti larvae were still susceptible to temephos.Conversely,most tested adults tended to resist the penmethrin and deltamethrin.

Deltamethrin:Promising mosquito control agent against adult stage of Aedes aegypti L.

Objective:To evaluate the effects of deltamethrin against field-collected adults of Aedes aegypti L(Ae.aegypti).Methods:The adults were selected with 0.025%deltamethrin for 40 successive generations.The selected adults were tested with 4%DDT and the emerging larvae were tested with various insecticides to study the cross-resistance spectrum.The knockdown and irritability studies were carried out in adult mosquitoes to investigate their behavioural response to deltamethrin.Results:Forty generations of selection with deltamethrin resulted in only 3.8-fold resistance in the adults of Ae.aegypti.The adults of parent(PS) and selected strains (DAS) exhibited only 0.8-fold cross resistance to 4%DDT.The larvae emerging from the PS and DAS strains did not develop appreciable levels of resistance to various insecticides tested.The knockdown studies revealed KTSO of 14.4 min in PS adults with no signs of recovery even after 24 h. The DAS strains could develop only 1.2 to 1.3-fold knockdown resistance(KDR).The knockdown response of DDT was though 5-6 times slower than deltamethrin but the continued response in deltamethrin-selected adults caused only 1.2-fold KDR.The PS and DAS strains exhibited significant irritability response towards deltamethrin and DDT.The DAS strains showed 5-6 fold increased irritability to deltamethrin as compared to the PS strain.Conclusions:The above results suggest the prolonged effective use of deltamethrin against Ae.aegypti as an adulticide.

Long Term Perinatal Deltamethrin Exposure Alters Electrophysiological Properties of Embryonic Ventricular Cardiomyocyte

Increased use of pyrethroids and the exposure to pyrethroids for pregnant women and children have raised the concerns over the potential effect of pyrethroids on developmental cardiotoxicity and other abnormalities.The purpose of this study was to investigate whether long tenn peri natal deltamethrin exposure altered embryonic cardiac electrophysiology in mice.Pregnant mice were administered with 0 or 3 mg/kg of deltamethrin by gavage daily from gestational day(gd)10.5 to gd 17.5.Whole cell patch-clamp technique was used in electrophysiological study,and real time RT-PCR was applied to analyze the molecular changes for the electrophysiological properties.Deltamethrin exposure resulted in increased mortality of pregnant mice and decreased viability of embryos.Moreover,deltamethrin slowed the maximum depolarization velocity(Vmax),prolonged the action potential duration(APD)and depolarized the maximuin diastolic potential(MDP)of embryonic cardiomyocytes.Additionally,perinatal deltamethrin exposure decreased the mRNA expression of Na^+channel regulatory subunit Navpl,inward rectifier K^+channel subunit Kir2.1,and delayed rectifier K^+channel subunit MERG while the L-type Ca^2+channel subunit,Cavl.2 expression was increased.On the contraiy,deltamethrin administration did not significantly alter the regulation ofβ-adrenergic or muscarinic receptor on embryonic cardiomyocytes.In conclusion,deltamethrin exposure at perinatal stage significantly alters mRNA expression of embryonic cardiac ion channels and therefore influences embryonic cardiac electrophysiological properties.This highlights the need to understand the persistent effects of pyrethroid exposure on cardiac function during embryonic development due to potential for cardiac arrhythmogenicity.

Impact of Indoor Residual-Sprayed Deltamethrin on Different Surfaces in a Malaria Endemic Area in Balai Ringin, Sarawak

Malaria control programme utilizing indoor residual spraying of chemical insecticide is only effective if a high coverage of targeted area is achieved. The effectiveness of the residual spraying, on the other hand, relies on the efficacy and residual activity of the insecticides applied, which to a certain extent are influenced by the nature of the sprayed surfaces. The bioefficacy of indoor residual-sprayed deltamethrin wettable granule (WG) formulation for the control of malaria was compared with the current dose of deltamethrin wettable powder (WP) in malaria endemic areas in Balai Ringin, Sarawak. Doses of 20 mg/m2 WP (control), 20 mg/m2 WG, 30 mg/m2 WG and 40 mg/m2 WG were sprayed separately on different surfaces namely, wooden, rough-bamboo, smooth-bamboo and brick surfaces. Residual activity of WP and WG formulations was tested against lab-bred Anopheles maculatus using WHO standard procedure. Deltamethrin at 30 mg/m2 WG exhibited the highest sustainable level of effectiveness against An. maculatus (An. maculatus mortality was between 95% - 100%) up to week 60 post-spraying when sprayed on smooth- bamboo surface. These results indicated that 30 mg/m2 WG could be an ideal concentration for controlling malaria vector effectively up to 15 months of which long-lasting residual spraying was envisaged. The usual two spraying cycles per year with 20 mg/m2 deltamethrin WP could be replaced with 30 mg/m2 deltamethrin WG since the long residual activity was achieved by employing a single spraying only.

First investigation of deltamethrin pyrethroid susceptibility and resistance status of Anopheles labranchiae(Falleroni, 1926), potential malaria vector in Tunisia

Objective: To evaluate the deltamethrin pyrethroid insecticides against Anopheles labranchiae, potential malaria vector in Tunisia.Methods: Six field populations of Anopheles labranchiae mosquitoes were collected from six localities in Northern and Central Tunisia between October and November 2016.Different bioassays were performed to estimate the level of resistance in each collected population. Two synergists were used to estimate the involvement of detoxification enzymes in insecticide resistance.Results: All studied strains were resistant and the RR50 ranged from 12.5 in sample #1 to72.5 in sample #6. Synergist tests using piperonyl butoxide indicated the involvement of monoxygenases enzymes in the recorded resistance. In contrast, the increase of deltamethrin mortality was not significant in presence of S,S,sributyl phosphorothioate(0.8 < SR < 1.2), suggesting no role of esterases(and/or GST) in the resistance phenotype. The correlation recorded between mortality due to DDT and the LC50 of deltamethrin insecticide indicated an insensitive sodium channel affected by Kdr mutation(Spearman rank correlation, r =-0.59, P < 0.01).Conclusions: These results should be considered in the current mosquitoes control programs in Tunisia. The use of pesticides and insecticides by both agricultural and public health departments in Tunisia should be more rational to reduce the development of resistance in populations. Different insecticide applications should be implemented alternately.

Distribution and Significance of Nitric Oxide Synthase in Brain Tissues of Rats Exposed to Deltamethrin Insecticide

The distribution of nitric oxide synthase(NOS)in brain tissues of rats exposed to deltamethrininsecticide has been examined by histochemical NADPH-diaphorase staining techniques on frozen sec-tions.After injection of deltamethrin(12.5mg/kg,i.p.),a reproducible sequence of toxic signs ofhyperexcitability were elicited.The observation and image analysis showed that,within brain sec-tions of rats exposed to deltamethrin,the numbers and the total staining areas of the NOS positiveneurons were greatly increased,especially in cerebral cortex,hippocampal formation and paraventric-ular nucleus.In addition,the density of single neuron and the processes were also increased.The re-sults suggested that deltamethrin may induce the NOS expression or activate the NOS activity.TheNOS activation may involve in the chains responsible for the excitatory neurotoxicities induced bydeltamethrin.

Variability of Deltamethrin-Resistant <i>Metarhizium anisopliae</i>Aggressive Strains Group to a Population of the Cossid Moth from <i>Eucalyptus nitens</i>

Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) was used to examine the genetic variability among Metarhizium anisopliae isolates tested to the cossid moth, Coryphodema tristis. All the isolates tightly clustered into one or the other of two groups that diverged at 12%. Results suggested that certain genotypes of the fungus, that grouped together, were able to infect moth larvae while others did not. A fragment of 760 bp, which presents high homology with a host-adaptation related protein coding gene, distinguished between aggressive and non-aggressive isolates. Neither mycelial growth nor sporulation rate or presence of known virulence genes was correlated with mortality values. Some isolates, including the most aggressive isolate ARSEF2518, were compatible with deltamethrin. Deltamethrin treatment killed all the larvae after seven days whereas fungal and mixed treatments respectively reached the same mortality after 28 and 21 days.

Ameliorative Effects of Spirulina platensis on Deltamethrin-Induced Biochemical Alterations and Oxidative Stress in the African Catfish;Clarias gariepinus

The present study was carried out to determine LC50 of deltamethrin (DM) in the African catfish;Clarias gariepinus, investigate its effects on the biochemical parameters and the antioxidant status of various tissues, and assess the protective role of Spirulina platensis (SP) against DM induced toxicity in C. gariepinus. The fish were distributed into seven groups of 10 fish/each for 30 days as follows: Group 1, control;Group 2, orally administered saline;Group 3, oral SP (150 mg/kg b.w.);Group 4, exposed to 5.19 μg/l DM;Group 5, exposed to 5.19 μg/l DM and orally administered SP (150 mg/kg b.w.);Group 6, exposed to 12.97 μg/l DM;and Group 7, exposed to 12.97 μg/l DM and orally administered SP (150 mg/kg b.w.). Results revealed marked elevation in serum AST, ALT, ALP, creatinine, urea and uric acid. Significant decrease in serum total protein and albumin was recorded. At the same time, the level of malondialdehyde (MDA) was significantly increased in liver, kidney and gills. While, tissue level ofGSHand, SOD,CATandGSH-Px activities were reduced. Treatment with SP improved the biochemical parameters and attenuated the DM induced oxidative damage. Therefore, this study confirmed the protective role of SP as an antioxidant against the toxicity of DM in catfish.

Sensitive determination of fenpropathrin,cyhalothrin and deltamethrin in environmental water samples using multiwalled carbon nanotubes cartridge prior to HPLC

这篇论文用多围的碳 nanotubes (MWCNT ) 为 fenpropathrin， cyhalothrin 和 deltamethrin 的踪迹决心描述了一个新方法子弹。重要参数例如样品最适 PH，洗脱液和它的体积，取样流量，样品体积详细被调查。线性范围，检测极限，和精确(R.S.D ) 在 0.1 40 μ g L 的范围 ? 1， 1.3 4.3 ng L ? 1 和 2.3 2.8% 分别地。建议方法的表演与真实的水样品被验证，并且刺的恢复在范围 91.7 117.8% 分别地。试验性的结果证明建议方法是为在环境样品的如此的污染物质的常规分析的一种优秀选择。

Oxidative Stress, Biochemical and Histopathological Alterations in the Liver and Kidney of Female Rats Exposed to Low Doses of Deltamethrin (DM):A Molecular Assessment

Objective To evaluate histopathological alterations of the liver and kidney of female rats exposed to low doses of DM and its potential genotoxic activity. Methods Female Wistar rats were randomly assigned to control (3 groups, 6 rats in each) and treatment groups (3 groups, 6 rats in each). They were subjected to subcutaneous injections of DM (at doses of 0.003, 0.03, and 0.3 mg/kg bw/d) after 30, 45, and 60 d, respectively. Results Significant alterations were recorded in liver parenchyma induced by hepatic vacuolization, fragmented chromatin in nuclei, dilatation of sinusoids and congestions. Lesions within proximal and distal tubules were observed in the kidneys. Tissue congestions and severe alterations within glomeruli were visible. DM as a pyrethroid insecticide induced significant increase (P≤0.05) of plasma MDA concentrations after 45 d. A significant increase (P≤0.05) in plasma ALT (after 45 and 60 d) and AST (after 60 d) concentrations was recorded as compared to controls. During the whole experimental period the toxic agent provoked significant DNA damages (P≤0.05), especially in the dominance of classes 3 and 4 of obtained comet. Conclusion DM even at a very low dose displays harmful effects by disrupting hepatic and renal function and causing DNA damages in puberscent female rats. Low doses of DM are hepatotoxic and nephrotoxic.

Effects of deltamethrin on the activation or expression of Nrf2 and on the GCS-HS protein level in primary astrocytes with laser scanning confocal microscope

Objective: To examine the effects of deltamethrin(DM) and tBHQ on the activation of Nrf2 and expression of GCS-HS in primary astrocytes. Methods: Rat primary astrocytes were treated with DM (10 μmol/L) and tBHQ (40 μmol/L), for 1 and 6 h respectively. Results: Analysis using immunofluorescent confocal microscopy revealed that tBHQ treatment led to a dramatic increase in the level of Nrf2. The ratio of cytoplasmic Nrf2 protein to nuclear Nrf2 protein was markedly reduced in astrocytes by either tBHQ or DM treatment. The level of Nrf2 was reduced by combined tBHQ with DM treatment for 1 h, but treatment the ratio of cytoplasmic Nrf2 protein to nuclear Nrf2 protein was increased compared with that of the tBHQ only. The expression of GCS-HS in astrocytes was not altered by DM or tBHQ or both in astrocytes. Conclusion: These findings demonstrated for the first time that Nrf2 was activated by pesticides and antioxidants in astrocytes, implicating a role of Nrf2 in response to pesticide neurotoxicity ingla.

Application of Gas Chromatography-mass Spectrometry in Analyzing Pharmacokinetics and Distribution of Deltamethrin in Miniature Pig Tissues

Objective To characterize the pharmacokinetics and distribution profiles of deltamethrin in miniature pig tissues by gas chromatography-mass spectrometry(GC-MS). Methods Pharmacokinetics and distribution of deltamethrin in blood and tissues of 30 miniature pigs were studied by GC-MS after oral administration of deltamethrin(5 mg/kg bw). Data were processed by 3P97 software. Results The serum deltamethrin level was significantly lower in tissues than in blood of miniature pigs. The AUC0-72 h, Cmax, of deltamethrin were 555.330±316.987 ng h/mL and 17.861±11.129 ng/mL, respectively. The Tmax, of deltamethrin was 6.004±3.131 h. Conclusion The metabolism of deltamethrin in miniature pigs is fit for a one-compartment model with a weighting function of 1/C2. Deltamethrin is rapidly hydrolyzed and accumulated in miniature pig tissues.

Metabolism of Deltamethrin in Rats

Objective To study the metabolism of 14C-deltamethrin in rats. Methods Rats were dosed orally and i.p. with a single dose of 14C-deltamethrin (0.64 mg/Kg) body weight. The required dose was applied daily for 3 days. At the end of the experiment, selected organs, such as liver, kidney, fat, intestine, and blood were excised for radioassay of 14C-content. Results Deltamethrin was almost eliminated from the body within 1-3 days. The main portion of 14C-residues was extracted from urine (38%, 32%) and feces (20%, 24%) with a little amount remained in various organs. Conclusion The elimination and distribution of 14C-radioactivity in rats treated orally and intraperitoneally signify that deltamethrin is bioavailable in urine and feces.

Tyrosine Hydroxylase as a Target for Deltamethrin in the Nigrostriatal Dopaminergic Pathway

Objective To study the effects of deltamethrin on tyrosine hydroxylase in nigrostriatum of male rats. Methods Sprague-Dawley rats were daily treated with deltamethrin at 6.25 or 12.5 mg/kg body weight by gavage for 10 days. Then HPLC-fluorescence detection was used to analyze the contents of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homoranillic acid (HVA) in substantial nigra and striatum. The activities of tyrosine hydroxylase (TH) were also detected by HPLC-fluorescence detection. TH mRNA or TH protein levels were measured by RT-PCR and immunohistochemistry method. Results The content of DA in striatum was significantly decreased by the treatments, suggesting an inhibition of DA synthesis by deltamethrin. The contents of DA metabolites DOPAC and HVA increased, indicating increased dopamine turnover. Furthermore, deltamethrin significantly decreased the activity, as well as the mRNA and protein levels of TH. Conclusions These findings reveal a novel aspect of deltamethrin neurotoxicity and suggest tyrosine hydroxylase as a molecular target of deltamethin on dopamine metabolism in the nigrostriatal pathway.

Levels of insecticide resistance to deltamethrin,malathion,and temephos,and associated mechanisms in Aedes aegypti mosquitoes from the Guadeloupe and Saint Martin islands(French West Indies)

Background:In the Guadeloupe and Saint Martin islands,Aedes aegypti mosquitoes are the only recognized vectors of dengue,chikungunya,and Zika viruses.For around 40 years,malathion was used as a mosquito adulticide and temephos as a larvicide.Since the European Union banned the use of these two insecticide molecules in the first decade of the 21st century,deltamethrin and Bacillus thuringiensis var.israelensis are the remaining adulticide and larvicide,respectively,used in Guadeloupe.In order to improve the management of vector control activities in Guadeloupe and Saint Martin,we investigated Ae.aegypti resistance to and mechanisms associated with deltamethrin,malathion,and temephos.Methods:Ae.aegypti mosquitoes were collected from six different localities of Guadeloupe and Saint Martin.Larvae were used for malathion and temephos bioassays,and adult mosquitoes for deltamethrin bioassays,following World Health Organization recommendations.Knockdown resistance(Kdr)genotyping for V1016I and F1534C mutations,and expression levels of eight enzymes involved in detoxification mechanisms were examined in comparison with the susceptible reference Bora Bora strain.Results:Resistance ratios(RR50)calculated for Ae.aegypti larvae showed high resistance levels to temephos(from 8.9 to 33.1-fold)and low resistance levels to malathion(from 1.7 to 4.4-fold).Adult females displayed moderate resistance levels to deltamethrin regarding the time necessary to affect 50%of individuals,varying from 8.0 to 28.1-fold.Molecular investigations on adult mosquitoes showed high resistant allele frequencies for V1016I and F1534C(from 85 to 96%and from 90 to 98%,respectively),as well as an overexpression of the glutathione S-transferase gene,GSTe2,the carboxylesterase CCEae3a,and the cytochrome genes 014614,CYP6BB2,CYP6M11,and CYP9J23.Conclusions:Ae.aegypti populations from Guadeloupe and Saint Martin exhibit multiple resistance to organophosphates(temephos and malathion),and pyrethroids(deltamethrin).The mechanisms associated with these resistance patterns show strong frequencies of F1534C and V1016I Kdr mutations,and an over-expression of CCEae3a,GSTe2,and four cytochrome P450 genes(014614,CYP9J23,CYP6M11,CYP6BB2).These results will form the baseline for a deeper understanding of the insecticide resistance levels and associated mechanisms of Ae.aegypti populations and will be used to improve vector control strategies in Guadeloupe and Saint Martin.

溴氰菊酯胁迫下家蚕品种辐7解毒酶基因的表达模式

昆虫体内解毒酶的过量表达和活性增强是昆虫对杀虫剂产生抗性的主要原因。辐射诱变家蚕品种辐7对菊酯类农药具有较强的耐受能力,研究溴氰菊酯胁迫下辐7体内解毒酶基因的表达模式,对于解析辐7的农药耐受性机制,培育耐农药污染的家蚕品种具有重要意义。根据不同浓度溴氰菊酯处理后辐7雄蛾的求偶和交配行为观察,最终选择2.5 mg/L溴氰菊酯处理组进行解毒酶基因的表达检测。采用荧光定量PCR检测溴氰菊酯处理后3 h和6 h辐7雄蛾触角解毒酶基因(8个羧酸酯酶基因、2个丝氨酸蛋白酶抑制剂基因、1个糜蛋白酶基因、3个脂肪酶基因、1个细胞色素P450基因和1个谷胱甘肽-S-转移酶基因)的转录水平:7个羧酸酯酶基因的表达先上调再下调,1个羧酸酯酶基因表达先下调再上调;1个细胞色素P450基因、1个丝氨酸蛋白酶抑制剂基因和1个糜蛋白酶基因表达先上调再下调;1个谷胱甘肽-S-转移酶基因、1个丝氨酸蛋白酶抑制剂基因和2个脂肪酶基因表达持续上调;1个脂肪酶基因表达在处理后6 h上调。结果表明,溴氰菊酯处理后诱导辐7雄蛾体内解毒酶基因转录水平上调,从而在一定程度上增强了辐7雄蛾对微量菊酯类农药的耐受性。

海洋生物体中氯氰菊酯、氰戊菊酯、溴氰菊酯残留测定的不确定度分析

根据计量的不确定度判断方法和表示理论,在标准溶液、试样称重、样品定容、标定曲线、仪器检测和试样测量六大领域,对气相色谱法检测的海洋生物体中溴氰菊酯、氰戊菊酯、次溴氰菊酯等有机物的不确定性分析与评价。结果表明,标准曲线所用溶液配制过程对测量结果的不确定度贡献较大,占总比重的28%。样品重复性测定和仪器重复性测量也引入了较多的不确定度,这为准确测量海洋生物体中的氯氰菊酯、氰戊菊酯和溴氰菊酯,减少测量不确定度,提升测量精度提供改进方向。

Photodegradation mechanism of deltamethrin and fenvalerate

To understand the degradation and environmental fate of pyrethroids,the process of their photodegradation under simulated natural conditions was investigated.The results showed that the degradation process follows first-order kinetics.The degradation intermediates were identified with gas chromatography-mass spectrometry.A plausible mechanism was discussed to explain the process.Several influences on degradation process were investigated and reported such as the effects of initial concentration of pyrethroids,total time of light irradiation,solvents,and light source,as well as the effect of a few substances that exist in the environment.This study could be a good reference for the degradation of pyrethroids in practical circumstances.