Novel mechanism and degradation kinetics of allethrin using Bacillus megaterium strain HLJ7 in contaminated soil/water environments.

As a common pyrethroid insecticide, allethrin is widely used for various purposes in agriculture and home applications. At present, allethrin residues have been frequently detected worldwide, yet little is known about the kinetics and degradation mechanisms of this insecticide. In this study, a highly efficient allethrin-degrading bacterium, Bacillus megaterium strain HLJ7, was obtained through enrichment culture technology. Strain HLJ7 can remove 96.5% of 50 mg L-1 allethrin in minimal medium within 11 days. The first-order kinetic analysis of degradation demonstrated that the half-life of allethrin degradation by strain HLJ7 was 3.56 days, which was significantly shorter than the 55.89 days of the control. The Box-Behnken design of the response surface method optimized the degradation conditions for strain HLJ7: temperature 32.18 °C, pH value 7.52, and inoculation amount 1.31 × 107 CFU mL-1. Using Andrews equation, the optimal concentration of strain HLJ7 to metabolize allethrin was determined to be 21.15 mg L-1, and the maximum specific degradation rate (qmax), half-rate constant (Ks) and inhibition coefficient (Ki) were calculated to be 1.80 d-1, 1.85 mg L-1 and 68.13 mg L-1, respectively. Gas chromatography-mass spectrometry identified five intermediate metabolites, suggesting that allethrin could be degraded firstly by cleavage of its carboxylester bond, followed by degradation of the five-carbon ring and subsequent metabolism. The results of soil remediation experiments showed that strain HLJ7 has excellent bioremediation potential in the soils. After 15 days of treatment, about 70.8% of the initial allethrin (50 mg kg-1) was removed and converted into nontoxic intermediate metabolites, and its half-life was significantly reduced in the soils. Taken together, these findings shed light on the degradation mechanisms of allethrin and also highlight the promising potentials of B. megaterium HLJ7 in bioremediation of allethrin-comtaminated environment.

Neurotoxicity associated with oxidative stress and inflammasome gene expression induced by allethrin in SH-SY5Y cells.

Pyrethroids, including allethrin, have largely been used as commercial insecticides. The toxicity of allethrin is little known, but it is assumed that, as occurs with other pyrethroids, it could cause alterations of the nervous system and pose both occupational and non-occupational health hazards. To evaluate the neurotoxicity of allethrin we used the MTT assay of SH-SY5Y neuroblastoma cells to determine cell viability. Dose-dependent reductions of cell viability served to compare the vehicle-group and the IC50 for allethrin, which was 49.19 µM. ROS production increased significantly at concentrations of 10-200 µM of allethrin, and NO levels were significantly increased by the effect of allethrin at a minimum concentration of 50 µM. Lipid peroxidation increased by the effect of allethrin at concentrations of 25, 50, 100, and 200 µM. Caspase 3/7 activity was induced by allethrin concentrations of 50, 100, and 200 µM. Here, we suggest that allethrin might affect the inflammasome complex (Caspase-1, NLRP3, and PYDC1) and apoptosis (Bax and Bcl-2) gene expression by mRNA fold change expression levels shown in Caspase-1 (2.46-fold), NLRP3 (1.57-fold), PYDC1 (1.48-fold), and Bax (2.1-fold). These results demonstrated that allethrin induced neurotoxicity effects on SH-SY5Y cells through activation of inflammasome pathways, cell death, and oxidative stress.

Allethrin Promotes Apoptosis and Autophagy Associated with the Oxidative Stress-Related PI3K/AKT/mTOR Signaling Pathway in Developing Rat Ovaries.

The increased concern regarding the reduction in female fertility and the impressive numbers of women undergoing fertility treatment support the existence of environmental factors beyond inappropriate programming of developing ovaries. Among these factors are pyrethroids, which are currently some of the most commonly used pesticides worldwide. The present study was performed to investigate the developmental effects of the pyrethroid-based insecticide allethrin on ovarian function in rat offspring in adulthood. We mainly focused on the roles of oxidative stress, apoptosis, autophagy and the related pathways in ovarian injury. Thirty-day-old Wistar albino female rats were intragastrically administered 0 (control), 34.2 or 68.5 mg/kg body weight allethrin after breeding from Day 6 of pregnancy until delivery. We found that allethrin-induced ovarian histopathological damage was accompanied by elevations in oxidative stress and apoptosis. Interestingly, the number of autophagosomes in allethrin-treated ovaries was higher, and this increase was correlated with the upregulated expression of genes and proteins related to the autophagic marker LC-3. Furthermore, allethrin downregulated the expression of PI3K, AKT and mTOR in allethrin-treated ovaries compared with control ovaries. Taken together, the findings of this study suggest that exposure to the pyrethroid-based insecticide allethrin adversely affects both the follicle structure and function in rat offspring during adulthood. Specifically, allethrin can induce excessive oxidative stress and defective autophagy-related apoptosis, probably through inactivation of the PI3K/AKT/mTOR signaling pathway, and these effects may contribute to ovarian dysfunction and impaired fertility in female offspring.

Pyrethroid based pesticides - chemical and biological aspects.

Human and animal welfare primarily depends on the availability of food and surrounding environment. Over a century and half, the quest to identify agents that can enhance food production and protection from vector borne diseases resulted in the identification and use of a variety of pesticides, of which the pyrethroid based ones emerged as the best choice. Pesticides while improved the quality of life, on the other hand caused enormous health risks. Because of their percolation into drinking water and food chain and usage in domestic settings, humans unintentionally get exposed to the pesticides on a daily basis. The health hazards of almost all known pesticides at a variety of doses and exposure times are reported. This review provides a comprehensive summation on the historical, epidemiological, chemical and biological (physiological, biochemical and molecular) aspects of pyrethroid based insecticides. An overview of the available knowledge suggests that the synthetic pyrethroids vary in their chemical and toxic nature and pose health hazards that range from simple nausea to cancers. Despite large number of reports, studies that focused on identifying the health hazards using doses that are equivalent or relevant to human exposure are lacking. It is high time such studies are conducted to provide concrete evidence on the hazards of consuming pesticide contaminated food. Policy decisions to decrease the residual levels of pesticides in agricultural products and also to encourage organic farming is suggested.

Comparative study of subchronic toxicities of mosquito repellents (coils, mats and liquids) on vital organs in Swiss albino mice.

The aim of the current study was to evaluate and compare the toxicities of different types of mosquito repellents i.e. coils, mats and liquid vapors in animal models. Different types of mosquito repellents including liquid vaporizers, coils and mats have been extensively used by the people to get protection from the mosquitoes and diseases associated with them. The active constituents of these repellents include; allethrins, pyrethrins, paraffin and various other derivatives, are well known for their toxicities. Exposure of albino mice to these repellents for 3 h per day over a period of 20 days produced significant toxicological effects on vital body organs including; liver, lungs, kidneys, brain and heart. The order of toxicity of different repellents on nervous and hepatic tissues was found to be: Coil > Liquid > Mat while in renal and cardiac tissues, the coil was again found to be the most toxic one, mat with medium toxicity whereas liquid as least toxic (Coil > Mat > liquid). Lungs tissues are almost equally affected by all the repellants. On the basis of current findings, it has been concluded that exposure to various types of mosquito repellents can be deleterious to health and can cause various health related issues by producing pathological changes in the vital organs.

Allethrin and prallethrin stimulates MUC5AC expression through oxidative stress in human airway epithelial cells.

Pyrethroids, including allethrin and prallethrin, have been widely used as major components of the common commercial insecticides. The toxicity of allethrin and prallethrin were well established that it interfered with the way that the nerves and brain function. However, limited information was available regarding respiratory effects in humans following inhalation exposure to allethrin and prallethrin. Therefore, we demonstrated effect of allethrin and prallethrin, and the mechanism involved, on the mucin expressions in human airway epithelial cells. In human airway NCI-H292 epithelial cells, the effects of allethrin and prallethrin and its signaling pathway for airway mucin, especially MUC5AC, were investigated by reverse transcriptase-polymerase chain reaction (RT-PCR), real-time PCR, and enzyme-linked immunosorbent assay (ELISA). The mechanism of allethrin and prallethrin-induced MUC5AC expression in airway epithelial cells was studied in terms of reactive oxygen species (ROS) by flow cytometry analysis. Allethrin and prallethrin significant increased MUC5AC expression in human airway NCI-H292 epithelial cells. We also demonstrated allethrin and prallethrin induced a marked rise of ROS production. In addition, NAC (ROS scavenger) and DPI (NADPH oxidase inhibitor) inhibited allethrin and prallethrin-induced MUC5AC expression. These results are first to describe that allethrin and prallethrin-induced MUC5AC expression through ROS in human airway epithelial cells.

Biochemical and histological alterations induced by the smoke of allethrin based mosquito coil on mice model.

BACKGROUND: Mosquito coil (MC) emits insecticide upon burning which provides limited protection against lethal mosquito borne diseases. However, apart from killing the insect, toxicities associated with the inhalation of these insecticides poses severe health hazards. However, the use of MC is increasing day by day in third world countries in particular but, yet to receive enough attention of both policy maker and general public. The current study was aimed to assess the MC smoke induced damage of pulmonary and hepatic tissues along with observing the alterations of several blood biochemical parameters in mice model. METHODS: A total of twenty four Swiss albino mice were allowed to inhale the smoke of allethrin based MC at different duration per day for 120 days. By the end of treatment period, blood sample was drawn from each mouse and blood biochemical parameters including alanine transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen(BUN), serum total protein, cholesterol, low density lipoprotein (LDL) and triglyceride (TG) were analyzed. Intact lung and liver were collected for histological analysis using standard protocol. RESULTS: Biochemical study indicates elevated activity of two hepatic enzymes: ALT (89%), AST (85%), in comparison with the respective control. Increased level of some parameters of lipid profile including cholesterol (36%), LDL (48%) and triglyceride (30%) in smoke inhaled mice is the new finding of this study. On the contrary, the activity of serum total protein and BUN was decreased by 20% and 24%, respectively in inhaled mice. Pulmonary tissue of treated mice shows severe forms of emphysema and hyperplasia, especially in the peripheral region of lung, which is the hallmark of chronic obstructive pulmonary disease (COPD). Histological study of hepatic tissue shows apoptosis mediated damage of hepatocytes along with severe form of necrosis. Infiltration of Inflammatory cells was also observed in both of the organs. CONCLUSION: Results from the present studies suggest that chronic exposure of allethrin based MC is responsible factor for severe health complications such as COPD due to the alterations of the key biochemical parameters of blood and histo-organization of lung and liver.

Exposure to allethrin-based mosquito coil smoke during gestation and postnatal development affects reproductive function in male offspring of rat.

The threat of zika virus looms throughout the world and the use of allethrin-based mosquito coils to prevent mosquito bites during and postpregnancy is on the rise. The aim of this study was to analyze the toxic effects of exposure to allethrin-based mosquito coil smoke in rats under conditions that reflect human settings. Pregnant female rats were exposed to mosquito coil smoke and same was continued to the male pups up to 111 days postparturition (21-day weaning plus up to 90 days postweaning). Increased oxidative stress, distorted antioxidant enzyme status, downregulation of genes involved in spermatogenesis, sperm maturation and steroidogenesis was observed. Daily sperm production, total sperm count and acrosome reaction was compromised. Results of our study indicate the toxic effects of exposure to allethrin-based mosquito coil smoke in male offspring and calls for preventing mosquito coil use during pregnancy and postnatal development. Community-based programs that will encourage general population to use classical methods such as use of mosquito nets, keeping the surroundings clean and use of natural mosquito repellents should be conducted.

Allethrin toxicity causes reproductive dysfunction in male rats.

Pyrethroids are widely used for domestic and agricultural purposes and their use is increasing, especially in developing countries. Uncontrolled use of these insecticides resulted in their entry into the food chain thereby causing toxicity to different organ systems. Allethrin is one of the widely used pyrethroids, but its toxicological effects are underreported when compared to other pyrethroids. Further, its effects on the male reproductive tract remain uncharacterized. In this study, its toxicity on the male reproductive tract was evaluated by administering 25-150 mg/kg body weight allethrin to adult rats for 60 days. The mRNA expression of factors that are important in spermatogenesis (Scf, c-Kit, Hsf2, Ovol1, Brdt, Kdm3A, Ybx-2, and Grth) and steroidogenesis (StAR, 3ß-HSD, 17ß-HSD) was significantly downregulated. Decreased levels of testosterone, reduced sperm count and daily sperm production was also observed due to allethrin toxicity. However, sperm quality parameters assessed by computer-assisted sperm analyzer were not affected. Spermatozoa obtained from allethrin-treated rats failed to undergo acrosome reaction. Results of this study indicate that allethrin affects spermatogenesis and sperm function, thus lending further support to the growing evidence of its toxicity.

Analysis of Pesticides and Toxic Heavy Metals Contained in Mosquito Coils.

In this study, 10 mosquito coils manufactured in China were obtained in Suriname, South America, where they are used extensively. The coils were analyzed for organics (allethrin, permethrin, and butylated hydroxytoluene) and heavy metals (Cr, Co, As, Cd, and Pb) by GC-MS and ICP-MS, respectively. Allethrin was the only target organic compound detected in all mosquito coils with concentrations ranging from ~1900 to ~4500 µg/g. The concentrations of heavy metals varied as follows (in µg/g): Cr: 2.9-9.4, Co: 0.1-1.2, Cu: 0.7-16.1, Se: 0.10-0.4, Ni: 2.1-5.8, As: 0.10-2.2, Cd: 0.10-0.2, and Pb: 1.1-3.6.

Allethrin-Based Mosquito Control Device Causing Knockdown, Morbidity, and Mortality in Four Species of Field-Caught Mosquitoes (Diptera: Culicidae).

A mosquito control device marketed for spatial repellency, the ThermaCELL Mosquito Repellent Appliance, was evaluated in semifield trials against multiple field-caught species of mosquito. Using paper and mesh cages, mosquito test groups of at least 30 mosquitoes were suspended in a 2,337 cubic foot outdoor space while two ThermaCELL repellent devices were active. After 30 min of treatment, cages were moved to the laboratory to observe knockdown, morbidity, and mortality for 24 h. Species tested included Aedes atlanticus Dyar and Knab (98% average mortality), Psorophora ferox Humboldt (97% average mortality), Psorophora columbiae Dyar and Knab (96% average mortality), and Aedes taeniorhynchus Wiedemann (84% average mortality). The repellent devices showed effectiveness with high knockdown and mortality across all species tested. Mosquito control devices like the ThermaCELL Mosquito Repellent Appliance may have further practical applications to help combat viral exposures by limiting host mosquitoes. Such devices may provide a functional alternative to DEET dependence in the current state of mosquito management.

Allethrin induced toxicity in the male reproductive tract of rats contributes to disruption in the transcription of genes involved in germ cell production.

Pyrethroids are known to be neurotoxic. However, their toxic effects including that of allethrin on the male reproductive tract are not elucidated. Adult male rats were treated orally with 25, 50, 100, and 150 mg/kg body weight allethrin every day for 60 days. Lipid peroxidation was increased (p < 0.001) in the caput, cauda, and testes. Nitric oxide production was increased (p < 0.001) in the caput, but unaltered in the cauda and testes. The activities of catalase, glutathione peroxidase, glutathione-S-transferase, and superoxide dismutase were decreased in the caput and cauda where as a decrease was observed in the testis obtained from allethrin treated rats. In the epididymides and testes, damage to tubular architecture, congestion, degeneration of epithelial cell lining, intestinal edema, and presence of dead or degenerating spermatids were observed in a dose dependent manner. The expression profile of genes involved in spermatogenesis (Tgf-beta1), sperm maturation (Spag11e), and sperm function (Defb22) were reduced (p < 0.001) in allethrin rats. The expression of p53 gene was decreased and increased phosphorylation of MAPK (p42/p44) expression was observed the male reproductive tract tissues of allethrin treated rats. Although earlier studies have reported the effects of allethrin inhalation because of the use of mosquito coils and vaporizers, our results for the first time prove that oral exposure to allethrin could affect fertility and may contribute to deregulation of cell cycle in the male reproductive tract.

The role of pyrethroid derivatives in autophagy and apoptosis crosstalk signaling and potential risk for malignancies.

Pyrethroids and its derivatives widespread and uncontrolled continuous use has influenced multiple deleterious effects resulting in as a potential risk factor causing damage to the organ systems. Allethrin and prallethrin are extensively used yet their influences on human primary cells are very limited or under reported. The potential mechanisms by which allethrin and prallethrin modulates human primary cells, especially the molecular mechanisms or interconnectivity of autophagy-apoptosis, their clinical relevance in human subjects or patients are not well defined. In this current study, we've furnished the evidence that both allethrin and prallethrin user samples significantly induced Ccl2 mRNA expression, increased amount of reactive oxygen intermediate, inhibited membrane bound enzymes and altered membrane fluidity. Pyrethroid derivative users had induced levels of lipid peroxidation and induced binding activities of transcription factors(tfs) like CEBP-ß and NF-AT. Pyrethroid derivatives induced autophagy, elicited intracellular Ca2+ concentration, calcineurin and regulated proapoptotic genes, DAPK1, Bim. Our current study presumably comprises the initial investigation of a very new mechanism of pyrethroid derivatives-moderated programed cell death in various cell sets or types, like human primary cells where-in this is a late event, is documented. Hence, current research-study might be significant in the various pyrethroid derivatives-allied hematological-related cancers and immunosuppressant or auto-immune disorders. In the foremost instance, we present data stating that pyrethroid derivatives induces multiple cell signaling cascades, like CEBP-ß, NF-AT, ERK and MAPK having a role in autophagy thereby; synchronously effectively impact on the apoptosis, therefore causing hematological tumors and toxic or immune related disorders.

Structural and vibrational investigation of Cis-Trans isomers of potent insecticide allethrin.

In this research, the optimised structural and vibrational properties of cis-trans isomers of powerful insecticide allethrin were theoretically studied in gas phase and in aqueous and ethanol solutions by using hybrid B3LYP/6-311 + + g(d,p) level of theory. The results revealed that the permittivity of solvent has influence on the properties of both isomers, thus, higher dipole moments and solvation energies are observed in water, a solvent of higher permittivity (78.355) than ethanol. Complete vibrational assignments of both isomers were done by combining the experimental IR spectrum of allethrin with the scaled quantum mechanical force field (SQMFF) methodology and the determination of corresponding scaled force constants in gas phase and aqueous solution are reported. Different signs of dihedral O2C10C6C4 angles of both isomers (negative in cis and positive in trans) support the differences in the vibrational assignments. Natural bond orbital (NBO) calculations suggest that both isomers are highly stable in gas phase and aqueous solution and that the side chains and five member's rings are involved in the n → σ* interactions. However, atoms in molecules (AIM) studies reveal a higher stability of form cis in both media than the trans one. Merz-Kollman (MK), Mulliken and natural population atomic (NPA) charges for both isomers support the higher hydration of trans isomer in aqueous media and, hence, the higher solvation energy in water (ΔGC/ZPVE = - 80.29 kJ/mol). Changes in the bond orders of O and C atoms of side chain are observed in water as a consequence of hydration. The higher stability of the cis form in the above solutions could be explained by the lower solvation energy in water, as supported by AIM calculations. The studies of frontier orbital reveal that the cis form in both media is sligthly more reactive than the trans form.

Phenotypic profile of Aedes albopictus (Skuse) exposed to pyrethroid-based mat vaporizers and underlying detoxification mechanisms: A statewide report in Selangor, Malaysia.

This study examines the biological efficacy of four mosquito mat vaporizers each containing different active ingredients: prallethrin with PBO, dimefluthrin, prallethrin, and d-allethrin. The glass chamber assay was used to evaluate their efficacy on Aedes albopictus (Skuse) (Diptera: Culicidae) from nine districts in Selangor, Malaysia. Aedes albopictus exhibited different knockdown rates, with 50% knockdown times, KT50, varying from 1.19 to 2.00 min, 1.22 to 2.20 min, 1.39 to 5.85 min, and 1.39 to 1.92 min for prallethrin with PBO, dimefluthrin, prallethrin and d-allethrin, respectively. In general, all populations of Ae. albopictus were completely knocked down after exposure to all active ingredients except Hulu Selangor population, which showed 96.00% knockdown against d-allethrin. On the contrary, mortality rates were observed from 84.00-100.00%, 84.00-100.00%, 90.67-100.00% and 90.67-100.00% in populations tested with prallethrin with PBO, dimefluthrin, prallethrin and d-allethrin, respectively. Moreover, significant correlations between mortality rates of prallethrin with PBO vs dimefluthrin (r = 0.836, P = 0.003), prallethrin with PBO vs prallethrin (r = 0.760, P = 0.011), and prallethrin vs d-allethrin (r = 0.694, P = 0.026) were also observed, suggesting cross-resistance among pyrethroids. d-allethrin was found to be high in insecticidal activity, followed by prallethrin, prallethrin with PBO, and dimefluthrin. In consistent with mortality due to insecticide exposure, elevated levels of enzyme activities were also demonstrated in Sabak Bernam, Hulu Selangor, Gombak, Petaling, Hulu Langat and Klang populations.

Biodegradation of Allethrin by a Novel Fungus Fusarium proliferatum Strain CF2, Isolated from Contaminated Soils.

Continuous use of allethrin has resulted in heavy environmental contamination and has raised public concern about its impact on human health, yet little is known about the kinetics and microbial degradation of this pesticide. This study reported the degradation kinetics in a novel fungal strain, Fusarium proliferatum CF2, isolated from contaminated agricultural fields. Strain CF2 utilized 50 mg·L-1 of allethrin as the sole carbon source for growth in minimal salt medium and tolerated high concentrations of allethrin of up to 1000 mg·L-1. The optimum degradation conditions for strain CF2 were determined to be a temperature of 26 °C and pH 6.0 using response surface methodology. Under optimum conditions, strain CF2 completely degraded allethrin within 144 hours. The degradation kinetics of allethrin followed first order reaction kinetics. Kinetics analysis showed that its half-life was substantially reduced by 507.1 hours, as compared to the uninoculated control. This study provides new insights into the microbial degradation of allethrin with fungal F. proliferatum CF2.

Mechanism of allethrin biodegradation by a newly isolated Sphingomonas trueperi strain CW3 from wastewater sludge.

The main aim of this study was to investigate and characterize the bacterial strain that has the potential to degrade allethrin. The isolated strain, Sphingomonas trueperi CW3, degraded allethrin (50 mg L-1) in batch experiments within seven days. The Box-Behnken design optimized allethrin degradation and had a confirmation of 93% degradation at pH 7.0, at a temperature of 30 °C and an inocula concentration of 100 mg L-1. The results from gas chromatography and mass spectrometry analysis confirmed the existence of nine metabolites from the degradation of allethrin with strain CW3. The cleavage of the ester bond, followed by the degradation of the five-carbon rings, was allethrin's primary degradation pathway. The strain CW3 also degraded other widely applied synthetic pyrethroids such as cyphenothrin, bifenthrin, permethrin, tetramethrin, ß-cypermethrin and chlorempenthrin. Furthermore, in experiments performed with sterilized soil, strain CW3 based bioaugmentation effectively removed allethrin at a significantly reduced half-life.

Binding interaction of allethrin with esterase: Bioremediation potential and mechanism.

The main aim of this work was to study the allethrin binding interactions with esterase and its bioremediation potential using an isolated bacterial strain CW7, identified as Pseudomonas nitroreducens. The degradation conditions with strain CW7 were optimized using response surface methodology at pH 7.0, a temperature of 32 °C, and an inocula concentration of 150 mg·L-1, with 96% allethrin degradation observed over 7 days. The kinetic parameters qmax, Ks, and Ki were calculated to be 0.512 day-1, 4.97 mg·L-1, and 317.13 mg·L-1, respectively. Nine intermediate metabolites were identified after analysing the degradation products by gas chromatography-mass spectrometry. Strain CW7 effectively degraded a wide variety of pyrethroids as a carbon source. Molecular modeling, docking, and enzyme kinetics were used to investigate the binding pocket of the esterase containing amino acids such as alanine, arginine, valine, proline, cysteine, glycine, isoleucine, phenylalanine, serine, asparagine, and threonine, which play active roles in allethrin degradation.

Vitamin E ameliorates testicular histological features and androgen binding protein levels in testicle of rats induced by allethrin.

OBJECTIVE: This study aims to determine the ameliorative effect of vitamin E (vit E) on histological features and androgen binding protein (ABP) levels in rats induced by allethrin. MATERIALS AND METHODS: Thirty sexually mature male Wistar rats weighing between 200 and 300 gm, and aging 3 months were taken for this study and were divided into three groups: negative control (NC), positive control (PC), and treatment (T) groups. The PC and T groups were induced by allethrin 12 h per day for 31 days; however, only the T group was given vit E orally at 1 ml/gm body weight (BW) each day for 14 days. The paraffin block method was used to measure tubules' diameter, thickness of the seminiferous epithelial layer, and Sertoli cell number. The ABP levels were measured by enzyme-linked immunosorbent assay. RESULTS: The results showed that vit E gave significant effect (p < 0.05) on tubular diameter at NC 123.67 ± 12.77, PC 147.16 ± 10.64, and T 130.08 ± 10.00; tubular epithelial thickness at NC 33.55 ± 3.21, PC 30.02 ± 1.53, and T 32.96 ± 2.81; Sertoli cells number at NC 55.48 ± 5.9, PC 43.84 ± 3.77, and T 53.44 ± 4.26; and ABP levels at NC 72.35 ± 39.06, PC 38, 48 ± 18.78, and T 86.10 ± 35.77, respectively. CONCLUSION: This study concludes that vit E has an ameliorative effect against the toxic effects of allethrin at testicular histological features and ABP levels.

Comparative Efficacy of Commercial Mosquito Coils Against Aedes aegypti (Diptera: Culicidae) in Malaysia: A Nationwide Report.

This study was conducted using the glass chamber method to determine the susceptibility status of the dengue vector, Aedes aegypti (L.) from 11 states in Malaysia to commercial mosquito coils containing four different active ingredients, namely metofluthrin, d-allethrin, d-trans allethrin, and prallethrin. Aedes aegypti exhibited various knockdown rates, ranging from 14.44% to 100.00%, 0.00% to 61.67%, 0.00% to 90.00%, and 0.00% to 13.33% for metofluthrin, d-allethrin, d-trans allethrin, and prallethrin, respectively. Overall, mortality rates ranging from 0.00% to 78.33% were also observed among all populations. Additionally, significant associations were detected between the knockdown rates of metofluthrin and d-allethrin, and between metofluthrin and d-trans allethrin, suggesting the occurrence of cross-resistance within pyrethroid insecticides. Overall, this study revealed low insecticidal activity of mosquito coils against Ae. aegypti populations in Malaysia, and consequently may provide minimal personal protection against mosquito bites.