Organophosphate

Efficacy of some locally available food lures such as molasses, sugar, country liquor and date palm juice (fresh and fermented) as bait components in attracting melon fly, Bactrocera cucurbitae (Coq.) were tested. Cypermthrin 10EC, chlorpyrifos 20 EC, spinosad 45SC, malathion 50EC, chlorpyrifos 50% + cypermethrin 5% and endosulfan 35 EC in cuelure bait were also used in bucket trap in a separate experiments. Both trials were conducted at the field of Instructional Farm, Uttar Banga Krishi Viswavidyalaya, Cooch Behar, West Bengal, India during 2007-2008. Results showed that the number of adult flies attracted per bait per day varied significantly in different baits being highest (3.22) in molasses followed by fermented date palm juice (3.18) and country liquor (2.11), whereas the lowest (0.67) was recorded in sugar. Highest number of flies was trapped in malathion traps (12.33) which had non-significant difference with chlorpyrifos + cypermethrin (11.67) and spinosad (10.67). Initial high number of flies trapped in various traps in both experiments decreased gradually over time.

Organophosphate (OP) pesticides and nerve agents are responsible for suicidal and accidental poisonings. The acute toxicity of nerve agents leads to progressive inhibition of the enzyme acetylcholinesterase (AChE) by phosphylation of serine residue at the active site of gorge. The recent massive destruction of Syrian civilians by nerve gas sarin, has again renewed the research attention of global science fraternity towards nerve agents, their mode of action and most prominently their therapeutic treatment. This review is principally focused on nerve agent intoxication. The common approach to deal with OP-intoxication is, application of antimuscarinic drug (atropine), anticonvulsant drug (diazepam) and clinically used oximes (pralidoxime, trimedoxime, obidoxime and asoxime). However, the existing therapeutic approach is arguable and has several failings to cure all kinds of nerve agent poisonings. Considering this issue, numerous oximes have been synthesized and screened through various in-vitro and in-vivo studies in last decade to overcome the downsides. At present, only a few oximes (bis pyridinum-oximes) exhibit sound efficacy against selective OPs. In spite of extensive efforts, till date no oxime is available as a universal antidote against all the classes of OPs. This review is centered on the recent developments and structural modification of AChE reactivators against nerve agent toxicity. In particular, a deeper look has been taken into chemical modifications of the reactivators by incorporation of different structural moieties targeted towards the increased reactivation affinity and improved blood brain barrier (BBB) penetration.

A collection of Culex pipiens from Boussalem, Northwestern Tunisia, with a low level of temephos resistance (14.90 at LD95) was selected to higher resistance with temephos in the laboratory. After 6 generations of pressure, the temephos resistance ratio increased to 103.95 at LD95. Synergism tests showed that temephos resistance was not associated with monooxygenase and esterases or (GST); however, evidence of insensitive acetylcholinesterase was found. It is evident that this important vector species, Culex pipiens, has the potential to develop resistance to temephos.

Louse is an external, obligate, blood-sucking parasite, which infects human societies. Improvements in health, economics, and social status of societies have reduced the parasitic lice infestation, however, it still is a global problem. Although it affects all age groups, school children are the most vulnerable age group. The high incidence of infection in children and their long-term close contacts transmit the infestation easily among them. In some parts of our country, organophosphate pesticides are widely used to control pests. Due to the ease of access to these toxins, poisoning with them are common and according to global statistics most deaths by pesticide are associated with organophosphate pesticides. Accordingly, we report 3 cases of a family from rural areas of Babol City. Upon being sprayed with an organophosphate solution, they developed severe organophosphate intoxication (OI) associated with central nervous system suppression.

Pesticides differ in their toxicity and potential to cause detrimental environmental impacts. Pest control materials that are
comparatively non-toxic with few ecological side-effects are called “bio-rational” pesticides. The major categories of bio-rational
pesticides include botanicals, microbials, minerals, and synthetic materials. Azadirachtin based insecticides are eco-friendly and are
well known for their varied pest control properties in contrast to synthetic insecticides. They work by inhibiting development of
immature stages of many insects and by deterring feeding by adults. But their use is limited due to the instability of azadirachtin.
Whereas, spinosad derived from a soil born bacterium- Saccharopolyspora spinosa, is also being used as an environmentally safe
product. Nicotine based imidacloprid, highly systemic and translaminar and the most widely used insecticide in the world has been
used for many years to control pests of agricultural crops, turf grass, and landscape plants; because of its low toxicity to mammals, it is
also used to control fleas and ticks on pets. Present study was carried out to find out the effectiveness of bio-rational insecticides
(biosal, spinosad and imidacloprid) in comparison with organochlorine (OC) and organophosphate (OP) insecticides (endosulfan and
profenofos) against jassid on brinjal crop. All the tested insecticides were effective against jassid except spinosad. The effectiveness of
both the imidacloprid and biosal proved to be a good alternative to endosulfan and profenofos.

The rapid emergence of various pesticides in the market is inevitable due to the demands from agriculture industries and domestic needs to control nuisance pests and to sustain green resources worldwide. However, long-term exposure to pesticide has led to adverse effects on male fertility. Organophosphate diazinon (O,O-diethyl-O-[2-isopropyl-6-methyl-4-pyrimidinyl] phosphorothiote) is an often abusively used pesticide, as it is effective and economical. This study is to determine the adverse effects of low-dose diazinon exposure on the male reproductive system. In this study, 72 Sprague-Dawley rats were segregated into 1, 2, and 8 weeks of exposure groups and further sub-grouped (n = 6) to receive 0, 10, 15, and 30 mg/kg body weight diazinon treatment. Rats were gavaged orally with diazinon and sacrificed under anaesthesia the day after the last exposure. Our results showed that consistent diazinon exposure decreased glutathione and catalase, and increased lipid peroxidation which together lead to diazinonmediated oxidative stress. Additionally, diazinon increased serum lactate dehydrogenase and decreased serum testosterone, which may have caused sperm and histopathological anomalies. In conclusion, exposure to diazinon caused changes in lipid peroxidation and sperm, and these two effects might be causally linked.

The use of organophosphate pesticides (OPPs) to protect a variety of crops has increased in Bangladesh.
OPPs may contaminate surrounding aquatic environments through several routes including spray drift, surface runoff and groundwater leaching. Since it is unknown how much OPP end ups in aquatic environment in Bangladesh, the objectives of the present study were to quantify the residues of ten most
commonly used OPPs in water and sediment of water bodies of north-west Bangladesh and to assess
their ecological risks for aquatic organisms. The risks of the pesticides in surface water and sediment
were assessed using a first-tier risk quotient (RQ) approach. The higher-tier PERPEST model was used to
refine the ecological risks of pesticides when RQ indicated a potential risk. Results showed the most
frequently detected pesticides that appeared in high concentrations were chlorpyrifos, diazinon and
quinalphos in surface water and sediment. The highest concentration of OPPs measured in water was
9.1 mg chlorpyrifos/L (median of 1.95 mg/L), while this was 51 mg diazinon/kg dw (median of 11 mg/kg dw)
for sediment. Furthermore, results showed high acute and/or chronic RQs (RQ > 1) in surface water and
sediment for chlorpyrifos, diazinon, quinalphos, malathion and fenitrothion. The higher-tier PERPEST
model confirmed risks of chlorpyrifos, diazinon, quinalphos and fenitrothion for aquatic insects, microand macro-crustaceans which were previously derived by RQ-based risk assessment for aquatic organisms. Furthermore, the results of the PERPEST model also indicated possible indirect effects of these
pesticides on algae and macrophytes, community metabolism, rotifers and other macro-invertebrates.

Acute toxicity of organophosphorus poisons (OP) is explained by inhibition of acetylcholinesterase in nerve synapses. Low dose effects are hypothesized to result from modification of other proteins, whose identity is not yet established. The goal of the present work was to obtain information that would make it possible to identify tubulin as a target of OP exposure. Tubulin was selected for study because live mice injected with a nontoxic dose of a biotinylated organophosphorus agent appeared to have OP-labeled tubulin in brain as determined by binding to avidin beads and mass spectrometry. The experiments with live mice were not conclusive because binding to avidin beads could be nonspecific. To be convincing, it is necessary to find and characterize the OP-labeled tubulin peptide. The search for OP-labeled tubulin peptides was begun by identifying residues capable of making a covalent bond with OP. Pure bovine tubulin (0.012 mM) was treated with 0.01-0.5 mM chlorpyrifos oxon for 24 h at 37 °C in pH 8.3 buffer. The identity of labeled amino acids and percent labeling was determined by mass spectrometry. Chlorpyrifos oxon bound covalently to tyrosines 83, 103, 108, 161, 224, 262, 272, 357, and 399 in bovine alpha tubulin, and to tyrosines 50, 51, 59, 106, 159, 281, 310, and 340 in bovine beta tubulin. The most reactive were tyrosine 83 in alpha and tyrosine 281 in beta tubulin. In the presence of 1 mM GTP, percent labeling increased 2-fold. Based on the crystal structure of the tubulin heterodimer (PDB 1jff) tyrosines 83 and 281 are well exposed to solvent. In conclusion seventeen tyrosines in tubulin have the potential to covalently bind chlorpyrifos oxon. These results will be useful when searching for OP-labeled tubulin in live animals.

Diazinon is one of the most widely used organophosphorus insecticides, to control plant pests in agricultural fields and is known to be a harmful environmental pollutant in the world. Therefore, the study aimed to investigate the hepatoprotective effects of alcoholic extract of Althaea officinalis against Diazinon-induced liver damage in adult male hamsters. 42 male hamsters were divided into six groups: The positive control group received distilled water, The negative control group received Diazinon poison, The group receiving the Althaea officinalis extract (300 mg/kg) and the group receiving the Althaea officinalis extract (600 mg/kg) received alcoholic extract of Althaea officinalis at doses of 300 mg/kg and 600 mg/kg of body weight, The group receiving Diazinon and the Althaea officinalis extract (300 mg/kg) and the group receiving Diazinon and the Althaea officinalis extract (600 mg/kg) received Diazinon toxin first and then alcoholic extract of Althaea officinalis at doses of 300 mg/kg and 600 mg/kg of body weight. Daily the hamsters were treated orally for 15 days. At the end of the experiment, blood samples were taken and serum levels of Alanine aminotransferase, Aspartate aminotransferase, Alkaline phosphatase, the whole (total) Bilirubin, the whole (total) protein and serum Albumin were measured. Data were analyzed by one-way ANOVA and Tukey's test using SPSS software. In Diazinon group, there was a significant increase in serum levels of Alanine aminotransferase, Aspartate aminotransferase, Alkaline phosphatase, the whole (total) Bilirubin and a significant decrease in serum (total) protein and Albumin levels compared with the positive control group. Alcoholic extract of Althaea officinalis caused a significant and dose-dependent decrease in the levels of hepatic enzymes and the whole (total) Bilirubin and significant increase in the whole (total) protein and serum Albumin levels. The result of this study showed that Althaea officinalis has a protective and therapeutic effect against Diazinon-induced hepatotoxicity in hamster.

The classical laboratory tests for exposure to organophosphorus toxicants (OP) are inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity in blood. In a search for new biomarkers of OP exposure, we treated mice with a biotinylated organophosphorus agent, FP-biotin. The biotinylated proteins in muscle were purified by binding to avidin-Sepharose, separated by gel electrophoresis, digested with trypsin, and identified from their fragmentation patterns on a quadrupole time-of-flight mass spectrometer. Albumin and ES1 carboxylesterase (EC 3.1.1.1) were found to be major targets of FP-biotin. These FP-biotinylated proteins were also identified in mouse plasma by comparing band patterns on nondenaturing gels stained for albumin and carboxylesterase activity, with band patterns on blots hybridized with Streptavidin Alexa-680. Two additional FP-biotin targets, AChE (EC 3.1.1.7) and BChE (EC 3.1.1.8), were identified in mouse plasma by finding that enzyme activity was inhibited 50-80%. Mouse plasma contained eight additional FP-biotinylated bands whose identity has not yet been determined. In vitro experiments with human plasma showed that chlorpyrifos oxon, echothiophate, malaoxon, paraoxon, methyl paraoxon, diazoxon, diisopropylfluorophosphate, and dichlorvos competed with FP-biotin for binding to human albumin. Though experiments with purified albumin have previously shown that albumin covalently binds OP, this is the first report of OP binding to albumin in a living animal. Carboxylesterase is not a biomarker in man because humans have no carboxylesterase in blood. It is concluded that OP bound to albumin could serve as a new biomarker of OP exposure in man.

Efficacy of some locally available food lures such as molasses, sugar, country liquor and date palm juice (fresh and fermented) as bait components in attracting melon fly, Bactrocera cucurbitae (Coq.) were tested. Cypermthrin 10EC, chlorpyrifos 20 EC, spinosad 45SC, malathion 50EC, chlorpyrifos 50% + cypermethrin 5% and endosulfan 35 EC in cuelure bait were also used in bucket trap in a separate experiments. Both trials were conducted at the field of Instructional Farm, Uttar Banga Krishi Viswavidyalaya, Cooch Behar, West Bengal, India during 2007-2008. Results showed that the number of adult flies attracted per bait per day varied significantly in different baits being highest (3.22) in molasses followed by fermented date palm juice (3.18) and country liquor (2.11), whereas the lowest (0.67) was recorded in sugar. Highest number of flies was trapped in malathion traps (12.33) which had non-significant difference with chlorpyrifos + cypermethrin (11.67) and spinosad (10.67). Initial high number of flies trapped in various traps in both experiments decreased gradually over time.

Current study was undertaken to evaluate the impact of repeated co-exposure of the widely used analgesic-antipyretic drug Acetaminophen (Paracetamol), Malathion (organophosphates pesticides), and metalloid (Arsenic) on the functions of the liver and pancreas of male albino rats. Eighty male albino rats weighing 140-160g were orally treated with Acetaminophen (100 mg/kg b.w), Malathion (30 mg/kg b.w) or Arsenic (1.5 mg/kg b.w) individually and in-combination for 28 days. Biochemical results revealed that all treatments under investigation showed significant increase in serum aspartate aminotransferase (AST) alanine aminotransferase (ALT) and amylase activities, as well as fasting glucose levels. Lipase recorded fluctuation in its activity according to treatment group, whereas cholinesterase activity (ChE) showed non-significant changes except for malathion treatment. In contrast, paraoxonase (PON1) and insulin activities were significantly declined after single and combined treatments at (P < 0.05). Histopathological changes in liver and pancreas tissues among all treated groups were recorded. These physiological and pathological observations were more prominent in combined treatments. In conclusion, association of environmental factors including drug therapeutic dose and pollutants might lead to different unexpected types and levels of toxicities.

Acute Toxicity of Veterinary and Agricultural Formulations of Organophosphates Dichlorvos and Diazinon in ChicksFormulation components of organophosphate insecticidal preparations might affect their toxic action in animals. The objective of this study was to examine and compare the acute toxicity and cholinesterase inhibition in seven to 14-day-old chicks dosed orally with dichlorvos and diazinon in standard veterinary and agricultural formulations. The acute (24 h) oral median lethal doses (LD50) of the formulations were determined using the up-and-down method. Respective LD50 of dichlorvos of the veterinary and agricultural formulations in chicks were 11.1 mg kg-1 and 6.51 mg kg-1 and those of diazinon 6.4 mg kg-1 and 6.7 mg kg-1. Plasma and brain cholinesterase activities were measured by electrometry after in vivo and in vitro exposure to organophosphates. The chicks showed signs of cholinergic toxicosis within one hour of dosing. Dichlorvos (8 mg kg-1) and diazinon (4 mg kg-1) ...

The snakehead Channa striata is an economically important air-breathing fish species in the Mekong delta of Vietnam. Rice paddies, which are disturbed by the frequent application of agro-chemicals, are among the preferred habitats for this species during the rainy season. Diazinon is one of most commonly used chemicals in rice paddies. In the present study, exposure of adult snakehead fish to a single diazinon application in cages within a rice field resulted in long-term brain cholinesterase inhibition, while the water concentration of this insecticide fell below the detection limit within 3 days. In addition, incubation of brain homogenates with 2-PAM caused reactivation of the cholinesterase diazinon complex to within 80% of the control level. These experiments also showed that chemical ageing of the diazinon cholinesterase binding occurred, which may explain the long-term effects of this pesticide.

Three species of freshwater Brazilian fishes (pacu,Piaractus mesopotamicus; piavussu,Leporinus macrocephalus, and curimbatá,Prochilodus lineatus) were exposed to an acute dose of 5 ppm methyl parathion organophosphate pesticide. Three to five individuals per species were exposed, one at a time, to 40 liters tap water spiked with Folidol 600. Pesticide concentrations and cholinesterase (ChE) activities were evaluated in serum, liver, brain, heart, and muscle. The bioconcentration of methyl parathion was similar for all studied fishes. Brain tissue showed the highest pesticide concentration, reaching 80 ppm after exposure for 30 min to methyl parathion. Three to 5 hours of 5 ppm methyl parathion exposure provoked the death of allP. lineatusat 92% brain AChE inhibition, whereas fish from the other two species survived for up to 78 hours with less than 80% brain AChE inhibition. Our results indicate that acute toxic effects of methyl parathion to fish are correlated with brain AChE sens...

OBJECTIVE To develop a convenient and efficient means for organophosphate (OP) insecticide detection, a simple, cost-effective, and easy-to-use absorbance-based sensing device was generated using methyl parathion hydrolase fused with glutathione-S-transferase (MPH-GST) covalently immobilized onto a chitosan film-coated microplate. RESULTS With methyl parathion (MP) as a representative substrate, this MPH-GST sensing microplate had the detection limit of 0.1 µM and the linear range of 0.1-50 µM. Despite its highest stability at 4 °C, it was considerably stable at 25 °C with high activity for 30 days. It was also most stable at pH 8.0 and could be efficiently reused up to 100 rounds. The device revealed a high percentage of recovery for tap water spiked with a known concentration of MP, which was also comparable to the result obtained from gas chromatography-mass spectrometry. It also showed a high recovery of 82-100% with MP spiked agricultural products and satisfactory results with ...

The authors report 2 cases of organophosphate poisoning which developed intermediate syndrome. The first case was a man who took an organophosphate insecticide, monocrotophos, and developed severe organophosphate poisoning. Respiratory support was needed. He was treated with atropine and 2-PAM. Weakness of neck muscles, proximal limb and respiratory muscle developed in the 3rd day after ingestion. By supportive treatment and careful monitoring, however, he recovered after 11 days of the poisoning. The second case was a lady who took dicrotophos. She developed severe organophosphate poisoning for which respiratory support was also needed High dose of atropine, but without 2-PAM, was administered. She developed bulbar palsy, proximal muscle and respiratory weakness 3 day after the ingestion. Ventilation support was needed for 13 days before weaning was successful. This report did not support an efficacy of pralidoxime (2-PAM) in alleviation of the intermediate syndrome, but aims to al...

Background: This study has used biomarker of exposure-effect continuum to examine the biological characteristics of organophosphate (OP) toxicity and its genotoxic effect among rice farmers.
Materials and Methods: A cross-sectional study was conducted among 160 pesticide exposed rice farmers and 160 adults from the fishing village as the unexposed group. They share the common socio-economical background for inter-individual comparison in human toxicology assessment. In this study depression of blood cholinesterase is used as a biomarker of exposure to OP toxicity. Two genotoxic assays (micronuclei and comet assay) were conducted as a biomarker of genotoxic effect among the adult population. In this context, micronuclei assay is used to indicate the chromosome breakage and comet assay to estimate the possible DNA damage.
Results: The study showed a significant difference of blood cholinesterase level (p=0.001) between the exposed-unexposed groups. Besides, the results showed that farmers had at least 2-2.5 folds of significant increase (p=0.001) in MN frequency (in 1000 cells) and comet tail length (µm) compared to the unexposed group. In addition, regression analysis among farmers showed that blood cholinesterase level decreased with the genotoxic effects. A small variation (R2=0.148) of MN frequency could be explained by the depression of blood cholinesterase level; however, a significant reduction (p=0.001), with strong changes (R2=0.712) in comet tail length was attributed to the depression of blood cholinesterase levels. Risk factors like age, body mass index, smoking status and years of working showed the different strength of the relationship with these genotoxic effects.
Conclusions: This study suggests that chronic exposure to OP shows an inhibition to blood cholinesterase level, which is associated with the potential DNA breakage as indicated by comet assay. Age, smoking and years of working are the contributing factors influencing the biomarker of effects.

The rapid emergence of various pesticides in the market is inevitable due to the demands from agriculture industries and domestic needs to control nuisance pests and to sustain green resources worldwide. However, long-term exposure to pesticide has led to adverse effects on male fertility. Organophosphate diazinon (O,O-diethyl-O-[2-isopropyl-6-methyl-4-pyrimidinyl] phosphorothiote) is an often abusively used pesticide, as it is effective and economical. This study is to determine the adverse effects of low-dose diazinon exposure on the male reproductive system. In this study, 72 Sprague-Dawley rats were segregated into 1, 2, and 8 weeks of exposure groups and further sub-grouped (n = 6) to receive 0, 10, 15, and 30 mg/kg body weight diazinon treatment. Rats were gavaged orally with diazinon and sacrificed under anaesthesia the day after the last exposure. Our results showed that consistent diazinon exposure decreased glutathione and catalase, and increased lipid peroxidation which together lead to diazinonmediated oxidative stress. Additionally, diazinon increased serum lactate dehydrogenase and decreased serum testosterone, which may have caused sperm and histopathological anomalies. In conclusion, exposure to diazinon caused changes in lipid peroxidation and sperm, and these two effects might be causally linked.

The current investigation aimed to evaluate endocrine disruption and oxidative stress of subchronic coexposure of Malathion (500 ppm), Arsenic (50 ppm) and Paracetamol (100 mg/kg b.w) in white rats. Eighty adult male albino rats weighing 120-140 g were orally treated with these agents individually or in-combination for 28 days (4weeks).Changes in body weight gain, blood total triiodothyronin (T3), thyroxin (T4), testosterone, lipid peroxidation (MDA), total antioxidants capacity (TAC) and total proteins (TP); besides some histopathological and morphometrical analysis of testis and thyroid tissues were evaluated. Exposure to selected xenobiotics individually or combined showed general decrease in body weight; a significant reduction in T3 level in Paracetamol combined treated groups; a significant increase in T4 among Arsenic treated groups; as well as reduction in testosterone level in all treated groups. A significant elevation in MDA concomitant with reduction in TAC and significant increase in TP level were recorded in all treated groups as compared to control level. Histological examination revealed spermatogenic arrest, edema in interstitial spaces in most treated groups, meanwhile thyroid tissues displayed cystic dilatation in thyroid follicles, colloidal depletion and degenerative changes in folliculocytes. Morphometric measurements showed reduction in Leydig cells count, reduction in follicular cells height reflecting their impairments which confirm the biochemical changes. Join action analysis of these xenobiotics reflected synergistic reactions on body weight and testosterone activity, whereas appeared to be antagonistically onT3, T4 and TAC. On the other hand, MDA and total protein showed additive effects. These results revealed that Malathion, Arsenic and Paracetamol reacted differentially to the tested parameters.

Parasuicide by ingestion of organophosphate (OP) insecticides is common in Sri Lanka, but the use of the parateral route to self administer the poison is extremely rare. We report a patient who deliberately injected herself intramuscularly with an OP compound with suicidal intent. The clinical manifestations of OP poisoning were unpredictable and posed a therapeutic problem.

Organophosphate (OP) and carbamate acetylcholinesterase (AChE) inhibitors produce seizures and lethality in mammals. Anticonvulsant and neuroprotective properties of N-methyl-D-aspartate (NMDA) antagonists encourage the investigation of their effects in AChE inhibitor-induced poisonings. In the present study, the effects of dizocilpine (MK-801, 1 mg/kg) or 3-((RS)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP, 10 mg/kg), alone or combined with muscarinic antagonist atropine (1.8 mg/kg), on convulsant and lethal properties of an OP pesticide dichlorvos or a carbamate drug physostigmine, were studied in mice. Both dichlorvos and physostigmine induced dose-dependent seizure activity and lethality. Atropine did not prevent the occurrence of convulsions but decreased the lethal effects of both dichlorvos and physostigmine. MK-801 or CPP blocked or attenuated, respectively, dichlorvos-induced convulsions. Contrariwise, NMDA antagonists had no effect in physostigmine-induced seizures or lethality produced by dichlorvos or physostigmine. Concurrent pretreatment with atropine and either MK-801 or CPP blocked or alleviated seizures produced by dichlorvos, but not by physostigmine. Both MK-801 and CPP co-administered with atropine enhanced its antilethal effects in both dichlorvos and physostigmine poisoning. In both saline- and AChE inhibitor-treated mice, no interaction of the investigated antidotes with brain cholinesterase was found. The data indicate that both muscarinic ACh and NMDA receptor-mediated mechanisms contribute to the acute toxicity of AChE inhibitors, and NMDA receptors seem critical to OP-induced seizures.

Organophosphates (OPs) are hazardous pesticides, but an indispensable part of modern agriculture; collaterally contaminating agricultural soil and surrounding water. They have raised serious food safety and environmental toxicity that adversely affect the terrestrial and aquatic ecosystems and therefore, it become essential to develop a rapid bioremediation technique for restoring the pristine environment. A newly OPs degrading Arthrobacter sp. HM01 was isolated from pesticide-contaminated soil and identified by a ribotyping (16S rRNA) method. Genus Arthrobacter has not been previously reported in chlorpyrifos (CP) degradation, which shows 99% CP (100 mg L −1) degradation within 10 h in mMSM medium and also shows tolerance to a high concentration (1000 mg L −1) of CP. HM01 utilized a broad range of OPs pesticides and other aromatic pollutants including intermediates of CP degradation as sole carbon sources. The maximum CP degradation was obtained at pH 7 and 32 °C. During the degradation, a newly identified intermediate 2,6-dihydroxypyridine was detected through TLC/HPLC/LCMS analysis and a putative pathway was proposed for its degradation. The study also revealed that the organophosphate hydrolase (opdH) gene was responsible for CP degradation, and the opdH-enzyme was located intracellularly. The opdH enzyme was characterized from cell free extract for its optimum pH and temperature requirement, which was 7.0 and 50 °C, respectively. Thus, the results revealed the true potential of HM01 for OPs-bioremediation. Moreover, the strain HM01 showed the fastest rate of CP degradation, among the reported Arthrobacter sp.

The present investigation has been designed to study the effect of sublethal concentrations of
Chlorpyrifos, on the haematological parametes of Heteropneustes fossilis (Bloch) after exposure to 96
hours. The present study shows the alternation in haematological parameter such as significant decrease
in RBC counts, Hb %, thrombocytes, monocytes %, eosinophils % and basophils % where as significant
increase in WBC count, Lymphocytes % and NeutrophilS % in chlorpyrifos exposed fish. The response
of the fish towards toxicity of chlorpyrifos was grossly dependent on concentration and length of
exposure. Thus, this paper gives an overview of the manipulation of fish, Heteropneustes fossilis as a
biomarker of pesticides through alternation in haematological parameters.

OBJECTIVE To develop a convenient and efficient means for organophosphate (OP) insecticide detection, a simple, cost-effective, and easy-to-use absorbance-based sensing device was generated using methyl parathion hydrolase fused with glutathione-S-transferase (MPH-GST) covalently immobilized onto a chitosan film-coated microplate. RESULTS With methyl parathion (MP) as a representative substrate, this MPH-GST sensing microplate had the detection limit of 0.1 µM and the linear range of 0.1-50 µM. Despite its highest stability at 4 °C, it was considerably stable at 25 °C with high activity for 30 days. It was also most stable at pH 8.0 and could be efficiently reused up to 100 rounds. The device revealed a high percentage of recovery for tap water spiked with a known concentration of MP, which was also comparable to the result obtained from gas chromatography-mass spectrometry. It also showed a high recovery of 82-100% with MP spiked agricultural products and satisfactory results with ...

The authors report 2 cases of organophosphate poisoning which developed intermediate syndrome. The first case was a man who took an organophosphate insecticide, monocrotophos, and developed severe organophosphate poisoning. Respiratory support was needed. He was treated with atropine and 2-PAM. Weakness of neck muscles, proximal limb and respiratory muscle developed in the 3 rd day after ingestion. By supportive treatment and careful monitoring, however, he recovered after 11 days of the poisoning. The second case was a lady who took dicrotophos. She developed severe organophosphate poisoning for which respiratory support was also needed. High dose of atropine, but without 2-PAM, was administered. She developed bulbar palsy, proximal muscle and respiratory weakness 3 day after the ingestion. Ventilation support was needed for 13 days before weaning was successful. This report did not support an efficacy of pralidoxime (2-PAM) in alleviation of the intermediate syndrome, but aims to alert physicians to recognize the intermediate syndrome for which adequate respiratory care is the crucial key for its management.

Objective To develop a convenient and efficient means for organophosphate (OP) insecticide detection , a simple, cost-effective, and easy-to-use absor-bance-based sensing device was generated using methyl parathion hydrolase fused with glutathione-S-transferase (MPH-GST) covalently immobilized onto a chitosan film-coated microplate. Results With methyl parathion (MP) as a representative substrate, this MPH-GST sensing microplate had the detection limit of 0.1 lM and the linear range of 0.1-50 lM. Despite its highest stability at 4°C, it was considerably stable at 25°C with high activity for 30 days. It was also most stable at pH 8.0 and could be efficiently reused up to 100 rounds. The device revealed a high percentage of recovery for tap water spiked with a known concentration of MP, which was also comparable to the result obtained from gas chromatography-mass spectrometry. It also showed a high recovery of 82-100% with MP spiked agricultural products and satisfactory results with ...

The current investigation aimed to evaluate endocrine disruption and oxidative stress of subchronic co-exposure of Malathion (500 ppm), Arsenic (50 ppm) and Paracetamol (100 mg/kg b.w) in white rats. Eighty adult male albino rats weighing 120-140 g were orally treated with these agents individually or in-combination for 28 days (4weeks).Changes in body weight gain, blood total triiodothyronin (T3), thyroxin (T4), testosterone, lipid peroxidation (MDA), total antioxidants capacity (TAC) and total proteins (TP); besides some histopathological and morphometrical analysis of testis and thyroid tissues were evaluated. Exposure to selected xenobiotics individually or combined showed general decrease in body weight; a significant reduction in T3 level in Paracetamol combined treated groups; a significant increase in T4 among Arsenic treated groups; as well as reduction in testosterone level in all treated groups. A significant elevation in MDA concomitant with reduction in TAC and signific...

Objective To develop a convenient and efficient means for organophosphate (OP) insecticide detection , a simple, cost-effective, and easy-to-use absor-bance-based sensing device was generated using methyl parathion hydrolase fused with glutathione-S-transferase (MPH-GST) covalently immobilized onto a chitosan film-coated microplate. Results With methyl parathion (MP) as a representative substrate, this MPH-GST sensing microplate had the detection limit of 0.1 lM and the linear range of 0.1-50 lM. Despite its highest stability at 4°C, it was considerably stable at 25°C with high activity for 30 days. It was also most stable at pH 8.0 and could be efficiently reused up to 100 rounds. The device revealed a high percentage of recovery for tap water spiked with a known concentration of MP, which was also comparable to the result obtained from gas chromatography-mass spectrometry. It also showed a high recovery of 82-100% with MP spiked agricultural products and satisfactory results with non-spiked samples. This immobilized enzyme sensing system was more sensitive and efficient than the whole cell system from our previous work. Conclusions All of the advantages of the MPH-GST sensing microplate developed have rendered it suitable for rapid and convenient OP screening, and for being a bio-element for fabricating a potential optical biosensor in the future. Keywords Organophosphate Á Methyl parathion hydrolase Á MPH-GST Á Covalent immobilization Á Sensing microplate Abbreviations OP Organophosphate insecticide MP Methyl parathion AChE Acetylcholinesterase MPH Methyl parathion hydroloase MPH-GST Methyl parathion hydrolase fused with glutathione-S-transferase GC-MS Gas chromatography-mass spectrometry LOD Limit of detection NTA Nitrilotriacetic acid Supplementary Information The online version of this article (https://doi.

Organophosphorous pesticide diazinon was indirectly oxidized to diazoxon by means of electrogenerated Cl 2 , Br 2 or I 2 under galvanostatic conditions using rotating glassy carbon disk electrode. The rate of oxidation was the highest in the case of electrogenerated Br 2 . In the presence of electrogenerated Br 2 diazinon was completely converted to diazoxon after 15 min of electrochemical treatment at all concentrations investigated. On the basis of thermodynamic and kinetic arguments it was showed that diazinon oxidation is governed by both kinetics and speciation of halogen species. Diazoxon is rapidly formed during its reaction with active oxidant species, while formed diazoxon is being stable and not degraded at appreciable rate by reactive halogen species. Described oxidation procedure was used as a pre-step for diazinon detection using AChE test coupled with optical detection. Diazinon detection limit was reduced by three orders of magnitude compared to unoxidized diazinon. This enabled diazinon detection at the lowest possible concentration using described methodology, as determined by diazoxon detection limit.