Biodegradation of malathion by Acinetobacter johnsonii MA19 and optimization of cometabolism substrates

To enhance the removal efficiency of malathion in the wastewater from organophosphate pesticide mill, a bacterium, Acinetobacter johnsonii MA19, that could degrade malathion with cometabolisrn was isolated from malathion-polluted soil samples using enrichment culture techniques. Four kinds of additional compounds, sodium succinate, sodium acetate, glucose, and fructose were tested to choose a favorite carbon source for the cometabolism of strain MA19. The results showed that sodium succinate and sodium acetate could promote malathion biodegradation and cell growth. The investigation results of the effects of sodium succinate concentrations on the malathion biodegradation indicated that the more sodium succinate supplied resulted in quick degradation of malathion and fast ceils multiplied. Zero-order kinetic model was appropriate to describe the malathion biodegradation when the concentration of sodium succinate was more than 0.5144 g/L, The degradation rate constant （K） reached the maximum value of 3.5837 mg/（L·h） when the mass ratio of sodium succinate to malathion was 128.6 mg/mg. The aquatic toxicity of the malathion was evaluated using the test organism, Limnodrilus hoffmeisteri. The data obtained suggested that the toxicity of malathion could be ignored after 84 h biodegradation. Our result demonstrates the potential for using bacterium A. johnsonii MA19 for malathion biodegradation and environmental bioremediation when some suitable conventional carbon sources are supplied.

Effect of a single dose of malathion on spermatogenesisin mice

<abstract>Aim: To observe the acute effect of the organophosphorous insecticide malathion on testicular function in mice. Methods: The effects of a single dose of malathion [240 mg/kg (1/12 LD50)] on plasma acetylcholinesterase (ACE) activity, spermatozoa (epididymal cauda counts and teratozoospermia), testis and plasma testosterone concentration) were evaluated at day 1,8, 16, 35 and 40 after treatment. Results: The sperm count was decreased significantly 24 h after treatment and teratozoospermia was increased at day 35 and 40. The height of the seminiferous epithelium and the diameter of tubular lumen were decreased at day 8. The percentage of tubular blockade was increased between day 8 and 35. A decrease in testosterone plasma level was observed at day 16 after treatment. Conclusion: Malathion damages male reproduction. The depletion of seminiferous tubules and the increase in teratozoospermia may be a genotoxic damage to the renewing spermatogonia, but the possibility of spermatogenic/ spermiogenic disfunction due to a decrease in the plasma testosterone level can not be ruled out.

Effect of malathion on the male reproductive organs of earthworms, Eisenia foetida

Aim: To observe the cytotoxic effect of the organophosphate insecticide malathion in the reproductive tissues of the earthworms, Eisenia foetida. Methods: Worms were nourished in soil treated with malathion at single sub-lethal doses of 0, 80, 150, 300 and 600 mg-kg^(-1) soil. (LD_(50) = 880 mg kg^(-1) soil) and evaluated on days 1, 5, 15 and 30 after exposure. The body weights were recorded and male reproductive organs evaluated. Results: Malathion-treated animals showed a significant reduction in body weight in a dose-dependent manner. Malathion treatment modified the disposition of spermatozoa in the basal epithelium of the spermatheca. The Br-deoxyuridine test showed a significant rise in cells in phase S on days 5 and 15. Also, a higher percentage of spermatogonia with fragmented DNA were observed by means of the TdT-mediated dUTP nick-end labeling (TUNEL) technique in the spermatheca of treated animals. Conclusion: Treatment with malathion decreased the body weight and the spermatic viability in spermatheca, altering the cell proliferation and modifying the DNA structure of spermatogonia.

Lepidium meyenii (Maca) reduces spermatogenic damage induced by a single dose of malathion in mice

Aim: To observe the effect of the aqueous extract of hypocotyls of the plant Lepidium meyenii (Maca) on spermato-genic damage induced by the organophosphate insecticide malathion in mice. Methods: Mice were treated with 80 mg kg^(-1) of malathion in the presence or absence of an aqueous extract of Maca, which was orally administered 7, 14 or 21 days after injection of the malathion. Stages of the seminiferous epithelium were assessed by transillumination on days 0, 7, 14 and 21. Results: The administration of Maca increased significantly the length of stage 鈪?on days 7, 14 and 21 of treatment compared with the controls. An increase in the length of stage 鈪?occurred on day 14 of treatment. Malathion affected spermatogenesis by reducing the lengths of stage 鈪?on day 7, stages 鈪?and 鈪?鈪?on day 14 and a recovery of stages 鈪?鈪?on day 21. The magnitude of alteration in the length of stage 鈪?produced by malathion was significantly reduced by Maca on days 7 and 14. The length of stage 鈪?was increased when Maca was administered to mice treated with malathion. Assessment of the relative length of stages of the seminiferous epithelium showed that Maca treatment resulted in rapid recovery of the effect of malathion. Conclusion: Maca enhances spermatogenesis following spermatogenic damage caused by the organophosphorous pesticide.

Removal of Malathion from Aqueous Solutions and Waste Water Using Fly Ash

Fly ash, obtained from a thermal power plant, Anpara, Sonebhadra, India has been used as an effective ad-sorbent for the removal of malathion from aqueous solutions. The time required to attain equilibrium was found to increase from 40 to 60 minutes as the initial malathion concentration increases from 1 to 10 mg/L. The optimum pH value for adsorption was 4.50. The removal of malathion increased by increasing the tem-perature indicating endothermic nature of removal process. The fly ash exhibited first order rate kinetics and followed both Langmuir and Freundlich isotherm models. Endothermic nature of adsorption process was further supported from increasing values of Langmuir and Freundlich constants with increase in temperature. The adsorbent can be used as an economical product for the removal of malathion from wastewater also. A comparison of the adsorption capacity of fly ash with other adsorbents shows that fly ash can be used for the removal of malathion from aqueous solutions.

Comparative Study of Malathion Toxicity and General Esterases in Larvae and Adults from a Field Population of Oxya chinensis (Thunberg) (Orthoptera: Acridoidea)

The susceptibility of Oxya chinensis to malathion was compared in larvae and adults from a field population, collected from Jinyuan outskirt, Shanxi Province. The results showed that Oxya chinensis was more susceptible to malathion in the adult stage than in the larval stage. The LD50 values for malathion susceptibility of Oxya chinensis were 4.94 and 2.44 mg g-1 body weight in the larvae and adults respectively. The results indicated that the larvae were 2.02-fold less susceptible to malathion than the adults. The general esterases and the kinetics were characterized and compared between the two life stages and between females and males. Larval preparations of Oxya chinensis were more active than adult preparations in females and males. The larvae showed 1.18-, 1.49-, and 1.17- fold higher specific activities than the adults in females with α-NA, α-NB and β-NA respectively. In males, the ratios were 1.34-, 1.70-, and 1.06-fold. Female preparations were more active than those of males in the adults. The reverse results were observed in the larvae where male preparations were more active than female preparations. Kinetic studies showed that Km values of general esterases hydrolyzing α-NA, α-NB, and β-NA in the adult stage were 1.36-, 1.32- and 1.39-fold respectively, higher than those in the larval stage in females. In males, the ratios were 1.24-, 2.14-, and 1.20-fold. The esterase from male insects had a higher affinity (lower Km value) to the substrate than those from females. The results also showed that the Vmax values of general esterase hydrolyzing α-NA, α-NB, and β-NA in the two stages were similar. From the results of bioassays and biochemical analyses, it has been inferred that a higher level of resistance to malathion in larvae than in adults would appear to result from differences in the expression of resistance mechanisms in these two life stages. Enhanced esterase activities appeared to play a major role in resistance to malathion in both larvae and adults. From the analysis of inhibition in vitro, the esterases in the two life stages were B-type, and carboxylesterases were predominant enzymes in the composition of the esterases in the two stages.

Degradation of malathion by Pseudomonas during activated sludge treatment system using principal component analysis (PCA)

Popular descriptive multivariate statistical method currently employed is the principal component analyses （PCA） method. PCA is used to develop linear combinations that successively maximize the total variance of a sample where there is no known group structure. This study aimed at demonstrating the performance evaluation of pilot activated sludge treatment system by inoculating a strain of Pseudomonas capable of degrading malathion which was isolated by enrichment technique. An intensive analytical program was followed for evaluating the efficiency of biosimulator by maintaining the dissolved oxygen （DO） concentration at 4.0 mg/L. Analyses by high performance liquid chromatographic technique revealed that 90% of malathion removal was achieved within 29 h of treatment whereas COD got reduced considerably during the treatment process and mean removal efficiency was found to be 78%. The mean pH values increased gradually during the treatment process ranging from 7.36-8.54. Similarly the mean ammonia-nitrogen （NH3-N） values were found to be fluctuating between 19.425-28.488 mg/L, mean nitrite-nitrogen （NO3-N） ranging between 1.301- 2.940 mg/L and mean nitrate-nitrogen （NO3-N） ranging between 0.0071-0.0711 mg/L. The study revealed that inoculation of bacterial culture under laboratory conditions could be used in bioremediation of environmental pollution caused by xenobiotics. The PCA analyses showed that pH, COD, organic load and total malathion concentration were highly correlated and emerged as the variables controlling the first component, whereas dissolved oxygen, NO3-N and NH3-N governed the second component. The third component repeated the trend exhibited by the first two components.

Novel neuroprotective and hepatoprorective effects of citric acid in acute malathion intoxication

Objective: To study the effect of citric acid given alone or combined with atropine on brain oxidative stress, neuronal injury, liver damage, and DNA damage of peripheral blood lymphocytes induced in the rat by acute malathion exposure. Methods: Rats were received intraperitoneal(i.p.) injection of malathion 150 mg/kg along with citric acid(200 or 400 mg/kg, orally), atropine(1 mg/kg, i.p.) or citric acid 200 mg/kg+atropine 1 mg/kg and euthanized 4 h later. Results: Malathion resulted in increased lipid peroxidation(malondialdehyde) and nitric oxide concentrations accompanied with a decrease in brain reduced glutathione, glutathione peroxidase(GPx) activity, total antioxidant capacity(TAC) and glucose concentrations. Paraoxonase-1, acetylcholinesterase(ACh E) and butyrylcholinesterase activities decreased in brain as well. Liver aspartate aminotransferase and alanine aminotransferase activities were raised. The Comet assay showed increased DNA damage of peripheral blood lymphocytes. Histological damage and increased expression of inducible nitric oxide synthase(i NOS) were observed in brain and liver. Citric acid resulted in decreased brain lipid peroxidation and nitric oxide. Meanwhile, glutathione, GPx activity, TAC capacity and brain glucose level increased. Brain ACh E increased but PON1 and butyrylcholinesterase activities decreased by citric acid. Liver enzymes, the percentage of damaged blood lymphocytes, histopathological alterations and i NOS expression in brain and liver was decreased by citric acid. Meanwhile, rats treated with atropine showed decreased brain MDA, nitrite but increased GPx activity, TAC, ACh E and glucose. The drug also decreased DNA damage of peripheral blood lymphocytes, histopathological alterations and i NOS expression in brain and liver. Conclusions: The study demonstrates a beneficial effect for citric acid upon brain oxidative stress, neuronal injury, liver and DNA damage due to acute malathion exposure.

The Susceptibilities of Oxya chinensis(Orthoptera:Acridoidea) to Malathion and Comparison of the Esterase Properties from Three Collected Populations in Tianjin Area,China

The susceptibilities of Oxya chinensis to malathion were studied in three populations collected from outskirt of Tianjin, China, using bioassays and biochemical analysis. Populations were chosen to represent different exposure to insecticides： BDG （Beidagang; low exposure）, BD （Baodi; high exposure previously but low exposure now）, and JN （Jinnan; high exposure）. The results showed that the LD50 values of BD and JN populations were 3.95- and 12.02-fold and 3.64- and 10.07- fold higher than that of BDG population in females and males, respectively. The LD50 values in females were higher than those in males. The results of biochemical analysis indicated that the esterase （EST） activities in JN population were higher than those in BD and BDG populations. They showed that when α-NA, α-NB, and α-NA were used as substrates, females＇ EST activities of JN population were 1.11-, 1.30-, and 1.14-fold and 1.39-, 1.59-, and 1.54-fold higher than those of BD and BDG populations, respectively. When α-NA, α-NB, and β-NA were used as substrates, males＇ EST activities of JN population were 1.13-, 1.12-, and 1,00-fold and 1.20-, 1.14-, and 1.07-fold higher than those of BD and BDG populations, respectively. The results also showed that the specific activities of the females were higher than those of the males in the BD and JN populations, whereas the specific activities of the males were higher than those of the females in the BDG population. The results of bioassay were consistent with those of biochemical analysis. Thus, it was inferred that the elevated ESTs activities might play an important role in conferring the differences of susceptibility of O. chinensis to malathion in the three collected populations. Enzyme kinetic studies indicated that the Km and Vmax values were different among the three collected populations and between the females and the males. The observed changes in the kinetic parameters might be explained by differential expression patterns of isozymes so that the insect esterases have different affinities and maximum velocities toward the same substrate.

Biosorption of Malathion from Aqueous Solutions Using Herbal Leaves Powder

Commonly available herbal leaves powder namely Achyranthes aspera (uthareni) and Phyllanthus niruri (Nela usiri) are used as biosorbents for the removal of malathion in the present investigation. The efficiency of the biosorbents is tested for the determination of malathion using batch experiments under controlled conditions as a function of pH, contact time, initial malation concentration and the optimization amount of biosorbents. The quantification of malathion in aqueous samples, before and after equilibration with biosorbents is carried out by existing spectrophotometric method based on the oxidation of malathion with excess N-bromosuccinimide (NBS) and Rhodamine B at (?max = 550 nm) is used for the unconsumed NBS. The biosorption capacities are found to be pH dependent. The maximum adsorption is noticed at pH = 6 with a contact time of 120 minutes. Biosorption equilibrium isotherms are plotted for malathion uptake capacity (Qe) against residual malathion concentration (Ce) in solution. The Qe versus Ce sorption isotherms relationship is expressed mathematically by Langmuir and Freundlich models. The removal of malathion using biosorbents Achyranthes aspera (Uthareni) and Phyllanthus niruri (Nela usiri) from spiked river water samples are found to be 94% and 96% respectively. The developed eco-friendly potential biosorbents indicate that the present method can be successfully applied for the quantitative determination and removal of malathion from real water samples.

Effects of cyclodextrins on hydrolysis of malathion

Cyclodextrins （CDs）, with hydrophobic interior cavity and hydrophilic external surface, are capable of accelerating or inhibiting chemical degradation of organophosphorus pesticides through forming inclusion complexes between CDs and pesticides. This work evaluated the effects of CDs on hydrolysis of malathion in an attempt to assess their potential application in environmental approach. β-CD and its two derivatives, randomly methylated β-CD （RAMEB） and hydroxypropyl β-CD （HP-β-CD）, were tested. It was found that RAMEB could inhibit the hydrolysis of malathion, and this was the function of pH and temperature, the inhibitory effects increase with increasing concentration of RAMEB and elevating temperature between 15 and 35℃. On the other hand, β-CD and HP-β-CD have little or no stabilizing effects on malathion at all pH and temperature studied, except that the large concentration of β-CD and HP- β-CD can mildly reduce hydrolysis of malathion. Both 2 mol/L and 5 mol/L urea increase the inhibitory effects of RAMEB on hydrolysis of malathion at 25℃, oH 9.0.

Preventive effects of cannabis on neurotoxic and hepatotoxic activities of malathion in rat

Objective: To investigate the effect of Cannabis sativa extract on the development of neuroand hepato-toxicity caused by malathion injection in rats. Methods: The extract of Cannabis sativa was obtained from the plant resin by chloroform treatment. Δ~9-Tetrahydrocannabinol content of the extract(20%) was quantified using gas chromatography–mass spectrometry. The doses of cannabis extract were expressed as Δ~9-tetrahydrocannabinol content of 10 or 20 mg/kg. Malathion(150 mg/kg) was intraperitoneally administered followed after 30 min by the cannabis extract(10 or 20 mg/kg, subcutaneously). Rats were euthanized 4 h later. Malondialdehyde(MDA), reduced glutathione(GSH), nitric oxide and paraoxonase-1(PON-1) activity were determined in brain and liver. Brain 5-lipoxygenase and butyrylcholinesterase(BChE) activity were measured as well. Histopathological examination of brain and liver tissue was also performed. Results: Compared to controls, malathion resulted in increased oxidative stress in brain and liver. MDA and nitric oxide concentrations were significantly increased(P<0.05) and GSH significantly decreased with respect to control levels(P<0.05). Malathion also significantly inhibited PON-1 and BChE activities but had no effect on brain 5-lipoxygenase. Brain MDA concentrations were not altered by cannabis treatment. Cannabis at 20 mg/kg, however, caused significant increase in nitric oxide and restored the GSH and PON-1 activity. Brain BChE activity significantly decreased by 26.1%(P<0.05) after treatment with 10 mg/kg cannabis. Cannabis showed no effect on brain 5-lipoxygenase. On the other hand, rats treated with cannabis exhibited significantly higher levels of liver MDA, nitric oxide and PON-1 activity compared with the malathion control group. Rats treated with only malathion exhibited spongiform changes, neuronal damage in the cerebral cortex and degeneration of some Purkinje cells in the cerebellum. There were also hepatic vacuolar degeneration and dilated and congested portal vein. These histopthological changes induced by malathion in brain and liver were reduced to great extent by cannabis administration at 20 mg/kg. Conclusions: Our data suggest that acute treatment with cannabis alleviates the malathion-induced brain and hepatic injury in rats possibly by maintaining the levels of GSH and PON-1 activity.

Susceptibility of <i>Culex quinquefasciatus</i>(Diptera: Culicidae) to malathion in Sargodha district, Pakistan

The present study was designed to evaluate the susceptibility of Culex quinquefasciatuns against malathion in Sargodha district of Pakistan. The activities of detoxifying enzymes i.e., β-esterases, GSTs and monooxygenases were also estimated. Our results revealed 100 percent mortality in insecticide treated groups after 24 hours of exposure. There was no difference in the activities of insecticide detoxifying enzymes between control and treated groups. We concluded from our work that malathion is still effective against C. quinquefasciatuns in the area for control of mosquito population.

Near-Infrared Spectroscopy Coupled with Kernel Partial Least Squares-Discriminant Analysis for Rapid Screening Water Containing Malathion

Near-infrared spectroscopy coupled with kernel partial least squares-discriminant analysis was used to rapidly screen water containing malathion. In the wavenumber of 4348 cm-1 to 9091 cm-1, the overall correct classification rate of kernel partial least squares-discriminant analysis was 100% for training set, and 100% for test set, with the lowest concentration detected malathion residues in water being 1 μg·ml-1. Kernel partial least squares-discriminant analysis was able to have a good performance in classifying data in nonlinear systems. It was inferred that Near-infrared spectroscopy coupled with the kernel partial least squares-discriminant analysis had a potential in rapid screening other pesticide residues in water.

A Feasible Way of Degrading Malathion Pesticide under Laboratory Condition Using Phosphate Solubilizing Bacteria

An experiment was carried out for identification and determination of malathion degrading phosphate solubilizing bacteria isolated from the agricultural fields. In this study, malathion degrading phosphate solubilizing bacteria were identified using NBRIP (National Botanical Research Institute’s phosphate growth medium) media. A number of bacterial colonies were screened from agricultural fields. From primarily screened colonies 4 isolates were identified as phosphate solubilizing bacteria through qualitative and quantitative analysis. The isolated 4 bacterial colonies were inoculated in NBRIP broth media enriched with malathion pesticides to observe degradation of malathion pesticide under incubation study at three different temperatures (25°C, 30°C and 37°C). However, all the four isolates showed capability in degrading malathion pesticide. The study clearly revealed that phosphate solubilizing bacteria can be used in bioremediation of environmental pollution caused by malathion pesticide.

Remediation of Malathion Contaminated Soil Using Zero Valent Iron Nano-Particles

In this study, iron nano-particles were used to remediate malathion contaminated soil in the concentration range of 1 - 10 μg?g–1. The zero valent iron nano-particles were prepared by reducing ferric chloride solution with sodium boro- hydride for remediation of the soil. The optimized quantity of iron nano particles was found to be 0.1 g?kg–1 of soil con- taminated with 10 μg?g–1 of malathion. Malathion was determined in the soil after leaching to water at pH 8.2 and fol- lowed by its oxidation with slight excess of N-bromosuccinimide (NBS). The unconsumed NBS was estimated by measuring the decrease in the color intensity of rhodamine B. Degradation product formed during the oxidation of ma-lathion by zero valent iron was monitored by the Attenuated Total Reflectance Fourier Transform Infrared Spectros- copy (ATR-FTIR). The results clearly showed that quantitative oxidation of malathion was achieved within eight min- utes after the addition of zero valent iron nano particles.

Toxic Effects of Bound Malathion Residues in Rats

The level of bound malathion residues in treated wheat grain and its toxic effects on rats were investigated. Wheat grain was treated with [14C] malathion (specific activity: 2.76 MBq/mg) to determine the bioavailability of bound residues in rats. At the same time, grain was treated with nonlabeled malathion to test for possible toxic effects of bound residues in a subchronic (90 days) feeding study in rats at two dose levels. 10 and 100 ppm.It was observed that the level of malathion-bound residues amounted to 11.28% of the applied dose (for six months). Also, it was noted that the main route of [14C]-malathion excretion was through the urine. This signifies that grain-bound malathion was bioavailable. In subchronic test on rats bound malathion residues (both dose levels) induced effects to some extent in organ weight (spleen and adrenals), and blood ChE activity. In both, males and females, there was an increase in SGPT activity (lower dose), and in alkaline phosphatase in females (higher dose). Hematological data showed changes only in hemoglobin concentration in males (both dose levels).

Liver Damage by the Interaction of Malathion with Cimetidine in Rat

In this study the authors aimed to evaluate the oxidative stress enzymes indicative of liver damage in rats exposed to malathion （M）, subchronic form using cimetidine （C） and cimetidine plus malathion （M ＋ C）. Malathion, widely used organophosphorus insecticide worldwide, induces oxidative liver damage type; cimetidine is an antagonist of histamine H2-receptor, it has been shown to be an inhibitor of various CYP45o isoforms. Male Wistar rats weighing 200-250 g were studied, exposed to malathion orally for 3 weeks （0.15 mg/kg/day, 2 mg/kg/day, 15 mg/kg/day） and cimetidine 10 mg/kg/day. Malathion plus cimetidine affect susceptibility to oxidative stress and possibly modifies the antioxidant defense capacity directly or indirectly.

Assessment of malathion and its effects on leukocytes in human blood samples

In the present paper,we report a reproducible,cost effective,fast response method for detection of malathion and its effects on leukocytes in different human blood groups.Spectroscopic methods（UV-Vis spectrometry）and Fourier transform infrared coupled with solid phase extraction were applied for analyzing malathion content in human blood plasma.The spiking levels of malathion in the range of 0.1-1.7μg/mL were extracted from blood plasma samples using SPE.The present active functional groups（C=0;P-O-C;-OH;P=S）were also characterized.The recovery rate of malathion was 80%±4.5%.The calculated correlation coefficient was 0.9799,indicating the linearity of the results.The limit of detection（LOD）and limit of quantification（LOQ）were（0.1-1.7）μg/mL and（0.3-1.5）μg/mL,respectively.Malathion〈1.0μg/mL showed no significant change while higher levels of malathion exposure（1.5μg/mL and 3.0｜ig/mL）reduced the number of white blood cells.In conclusion,the spectroscopic results may be useful to understand the mechanism of other pesticides such as methyl parathion and parathion.

Developmental effects of Malathion exposure on locomotor activity and anxiety-like behavior in Wistar rat

Developmental exposure to organophosphate insecticide is well known to induce neurobeha-vioral impairments, at late period. The present study aims to investigate the effects of chronic exposure to Malathion, from in utero to young adult stage, on locomotor skills and anxiety like- behavior among wistar rat. Four groups of female rats, bred with one non-pesticide exposed male, are used. On gestational day 6, three groups receive daily, by intragastric gavage, 3 different doses of Malathion dissolved in corn oil (100, 200 and 300 mg/kg body weight). The control group receives the corn oil only. On postnatal day 21, weaned offsprings are submitted to the similar treatment until adult age. Spontaneous locomotor activity is evaluated using the Open-Field test (OF) and anxiety-like behavior is measured using both Open-Field (OF) test and Elevate Plus-Maze (EPM). Malathion at 300 mg/kg is toxic to pregnant dams, and pups are stillborns. In males, Malathionlevelat 100 and 200 mg/kg induced significant impairment of spontaneous locomotor activities, which is reflected by high decrease of number of squares crossed in OF. In contrast, no discernible changes are observed within females Malathion-treated-group. However, females exposed to both malathion levels develop further anxiety-like response, expressed by significant reductions of exploratory activities in OF and time spent in open arm of EPM. Neurochemistry assay shows that cerebellum and neocortex acetylcholinesterase (AChE) activity inhibition are significantly increased with neurobehavioral deficits in males, relative to females. Overall, neurobehavioral outcomes of current study reveal that developmental exposure to Malathion induces sex-selective effects with greater changes in females.