Neuroendocrine regulation and pesticidal impact on freshwater crab, Barytelphusa guerini (H. Milne Edwards).

The extensive use of pesticides to control agricultural pests poses a serious threat to many non-target organisms of the aquatic environment such as the freshwater crab, B. guerini. The deleterious influence of the pesticide causes physiological, biochemical, histological and such other disorders in the animal exposed. In the present study impact of an organophosphate pesticide, monocrotophos and neuroendocrine regulation on the biochemical contents of hepatopancreas of B. guerini has been studied. Experimental studies revealed that glycogen and protein content decreased in normal crabs when exposed to sub lethal concentrations of monocrotophos, while lipid content was increased. In the ablated and pesticide exposed crabs glycogen, protein and lipid contents decreased. In case of ablated and exposed crabs when injected with eyestalk extract, glycogen and protein contents declined, whereas lipid content hiked. It was observed that glycogen, protein and lipid contents in eyestalk extract injected crabs were similar to those of normal exposed crabs. This indicates the vital role of eyestalk in the regulation of biochemical contents. Histological studies of the hepatopancreas indicate structural changes such as large number of vacuolated cells and phagocytes when exposed to the pesticide.

Influence of endosulfan and monocrotophos exposure on the activity of NADPH cytochrome C reductase (NCCR) of Labeo rohita (Ham).

The response of NADPH cytochrome C reductase (NCCR) activity in liver of Labeo rohita fish exposed to the pesticides, 0.25 microgl(-1) endosulfan and 2 mg/l monocrotophos was studied. In terms of specific enzyme activity (mU/mg protein) a significant level of NCCR was observed in the liver tissues of Labeo rohita exposed to the pesticides, when compared to the control fish (2.460 mU/mg protein). Increase of NCCR activity was more in the liver of the fish exposed to monocrotophos (4.595 mU/mg protein) than those exposed to endosulfan (2.850 mU/mg protein). The results demonstrate that the pesticides, endosulfan and monocrotophos, interfere with NADPH dependent monoxygenase mechanism and are effective inducers of NADPH cytochrome C reductase. The activity of NCCR in the liver tissue of Labeo rohita may serve as a useful tool for monitoring aquatic pollution.

Impact of low dose of organophosphate, monocrotophos on the epithelial cells of gills of Cyprinus carpio communis Linn.--SEM study.

The paper deals with the deleterious changes at ultrastructural level of the epithelial cells of gills of Cyprinus carpio communis Linn. upon exposure to 1/10th of LC50 of monocrotophos which is considered to be insignificant concentration from toxicological point of view. The gills of the fish are the primary corridor formolecularexchange between the internal milieu of a fish and its environment. Gills perform numerous functions such as oxygen uptake and CO2 excretion, osmoregulation, acid-basic balance, excretion of nitrogenous compounds and taste. Hazardous chemicals present in water may alter the morphology of the epithelial cells of gills of the fish, which may affect the process of diffusion of gases and ultimately the overall health of the fish. To prove this fact Cyprinus carpio communis Linn. was kept in water for 30 days having low concentration of 0.038 ppm (1\10th of LC50) of monocrotophos and an attempt was made to study the different types of degenerations produced in the epithelial cells of gills as compared to the normal epithelial cells of gills of this culturable fish using Scanning Electron Microscope (SEM) technique. The ultrastructural changes due to the toxic exposure at finer scale were thinning of microridges, upliftment of epithelial cells, development of hyperplasia, decrease in the density of mucous cells which are considered to be the first line of defence and total dystrophy of epithelial tissue. Thus, it is opined that a low concentration of monocrotophos has the potential to bring different type of degenerations at finer scale hence affecting the fish's health drastically and altering the fitness of the fish in water even having insignificant amount of this toxicant in the ambient water

TLC-spectrophometric separation and trace determination of monocrotophos and dichlorvos in enviromental and biological samples.

Organophosphorus insecticides, monocrotophos and dichlrovos are increasingly being used in agriculture to control insects on a wide range of crops. Their ready access has resulted in misuse in many instances of homicidal and suicidal poisoning cases. This paper describes about a chromogenic spray reagent for the detection/determination of monocrophos and dichlrovos in environmental and biological samples by TLC and spectrophotometric method. Monocrotophos and dichlorvos on alkaline hydrolysis yield N-methyl acetoacetamide and dichlroacetaldehyde respectively, which in turn react with diazotized p-amino acetophenone to give red-violet and red coloured compounds. Other organophosphorus insecticides do not give this reaction. Moreover, organochlorine and synthetic pyrethroid insecticides and constituents of viscera (amino acids, peptides, proteins etc), which are generally coextracted with the insecticides, do not interfere. However, phenolic compounds and hydrolysed product of carbamate insecticides may interfere and differentiate from monocrotophos and dichlrovos by Rf values. The lower limit of detection is 0.2 mg for monocrotophos and 0.1 mg for dichlorovos. The absorption maxima of the reddish-violet and red colour formed by monocrotophos and dichlrovos, are measured at 560 nm and 540 nm respectively. Beer's Law is obeyed over the concentration range of 1.2 to 6.8 mg and 6.2 to 35 mg in the final solution volume of 25 mL. The molar absorptivity and Sandell's sensitivity of monocrotophos and dichlrovos were found to be 7.1 x 10(5) (+100) 1 mole(-1) cm(-1) and 0.008 mg cm(-2), 1.2 x 10(5) 1 mole(-1) cm(-1) and 0.003 mg cm(-2) respectively. The standard deviation and relative standard deviation were found be +/- 0.005 and 2.05% +/- 0.007 and 2.02% respectively. The developed method has been successfully applied to the detection and determination of monocrotophos and dichlrovos in environmental and biological samples.

Biomarkers of monocrotophos in a freshwater fish Channa punctatus (Bloch).

Activity of a few biomarkers have been investigated on freshwater fish Channa punctatus treated with monocrotophos for acute exposure to 18.56 ppm at 96 hr and subacute exposure viz. 0.46 ppm, 0.96 ppm and 1.86 ppm for 30 days. Biomarkers such as total protein, lipid peroxidation and acetylcholinesterase have been measured in different tissues of fish viz. gills, liver, brain and muscles. The protein levels were found to be depleted in all the tissues after pesticide exposure to lethal and sublethal concentration over the control, where as the lipid levels showed an increase under the stress of pesticide monocrotophos. The increased lipid level may be due to inhibition of lipase activity and other biomarkers of lipid metabolism. A significant inhibition of brain acetylcholinesterase (AChE) indicating its effects on nervous system have also been observed. These parameters can be used as biomarkers to predict the early toxicity of monocrotophos added to aquatic ecosystem.

Histopathological changes in liver, kidney and muscles of pesticides exposed malnourished and diabetic rats.

Histopathological changes were observed in liver, kidney and muscles of normal, protein-malnourished, diabetic as well as both protein-malnourished and diabetic albino rats when exposed to a mixture of monocrotophos, hexachlorocyclohexane and endosulfan at varying intervals. The examination revealed hepatotoxic, nephrotoxic and muscular necrotic effects in pesticides exposed rats. Toxicity was aggravated in protein-malnourished and diabetic animals and more so, if the animals were both diabetic and protein-malnourished.

Biochemical effects of some organophosphorus pesticides on the ovaries of albino rats.

An evaluation of the toxic effects of three organophosphates; monocrotophos, dimethoate and methyl parathion on female reproduction was made by biochemical estimations of cytoplasmic and membrance bound proteins, lipids, phospholipids and cholesterol in the rat ovaries after treatment with their low residual level doses (LD50 1/8-1/5) to three groups of six rats each for 90 days. All the three pesticides caused degenerative changes in the ovaries as evidenced by a significant decrease in the concentration of cytoplasmic as well as membrane bound proteins, total lipids, phospholipids and cholesterol. The observations are thus indicative of the reproductive toxicity caused by organophosphates at cellular and molecular level in the ovaries of rats.

Enzymatic changes induced by some organophosphorus pesticides in female rats.

An evaluation of toxic effects of three organophosphorus pesticides viz. monocrotophos, methyl parathion and dimethoate given orally daily for 90 days was done in terms of enzymatic changes in plasma and liver of female albino rats. A significant decrease was observed in the level of esterases in plasma with all the three pesticides. The activity of acid and alkaline phosphatases and aminotransferases increased significantly in plasma and significantly or marginally in liver with these pesticides. The results are thus indicative of the cellular toxicity of these organophosphates even after their subchronic administration in low doses for a long period.

Hydrolysis of organophosphorus compounds by an esterase isozyme from insecticide resistant pest Helicoverpa armigera.

Esterase activity of resistant and susceptible H. armigera were compared in gels with different substrate such as naphthyl acetate, naphthyl phosphate, paraoxon and monocrotophos. Whole body extract of resistant H. armigera hydrolyzed paraoxon, monocrotophos and naphthyl phosphate in gels. Resistant H. armigera showed high esterase, phosphatase and paraoxon hydrolase activity compared to susceptible ones.

SEM study on cytotoxic effect of monocrotophos (MCP) on lungs of rat.

Monocrotophos (MCP) on oral administration (0.28 mg/100 g of body wt. i.e. 1/5th of LD50) to female rats for 15 and 30 days damaged alveolar walls lined by type II cells (great alveolar cells); clara cells (non-ciliated cells) lining bronchiolar epithelium; and emphysematous lesions due to loss of inter-alveolar walls. This led to increase in surface tension in lung due to decrease in secretion of surfactant as a result of necrosis of great alveolar cells and clara cells resulting in hypoxia. This effect was time dependent. In R group (15 days without pesticide after 30 days daily oral treatment), the toxic effects mentioned above still persisted which revealed non-repair of necrosis caused by MCP.

Acute and sub-acute effects of 2-butenoic acid-3-(diethoxy phosphinothioyl) methyl ester (RPR-II) on testis of albino rat.

Acute and sub-acute toxic effects of a novel phosphorothionate coded as RPR-II on testis of albino rats were studied. In acute study rats received a single dose of 12.3 mg/kg of RPR-II and sacrificed after 24 hr. For sub-acute study 0.58 mg/kg/day was administered orally to rats for 10 and 21 days. Acute exposure of rats to RPR-II brought no change either in the gonadosomatic index (GSI) or in the structure of testis or in the serum levels of testosterone. Testis glutathione (GSH) level and glutathione S-transferase (GST) activity was significantly decreased whereas, acid phosphatase (AcP) levels increased significantly at 24 hr post-treatment. On 7th day (withdrawal period) after the cessation of the treatment the GSH, GST, AcP, and AkP levels reached to near control. The sub-acute study revealed a significant decrease in GSI on 10th and 21st day of the treatment. In contrast, a time-dependent and significant increased in GSH level and GST activity was observed on 100th and 21st day of post-treatment, except GSH level on 10th day, which was declined. Due to RPR-II treatment the testis AcP and alkaline phosphatase (AkP) levels were significant at both 10th and 21st day of medication but AcP levels were increased whereas AkP levels decreased. The histopathological studies on day 10th showed considerable loss of spermatozoids in testis and at 21st day complete derangement of cellular organization was observed. Testosterone levels decreased significantly on 10th day and remained significantly low at 21st day. However, withdrawal studies showed a recovery in testis of rat treated with RPR-II. GST, GSH, GSI, AcP and AkP values recovered, testosterone levels were also well recovered but recovery in testis structure remained at a low profile. The present study suggests that RPR-II may cause testicular toxicity in rats affecting the normal functioning of testis and it also gave some new information in withdrawal studies.

Avaliaçäo do potencial de lixiviaçäo de pesticidas em latossolo da regiäo de Guaíra, SP / Assessing leaching potential of pesticides in oxisol from Guaíra region, state of Säo Paulo, Brazil

Os potenciais de lixiviaçäo de dezenove pesticidas nos primeiros 60 cm de latossolo da regiäo de Guaíra, Estado de Säo Paulo, foram estimados mediante fator deatenuaçäo (AF). O modelo aplicado considerou propriedades do pesticida e do solo, assim como a taxa de recarga hídrica líquida. Os pesticidas com maior potencial de lixiviaçäo foram manocrotofós>carbofuranmetalaxil>aldicarb>metolactor>metamidofós. Para todos os pesticidas estudados naquele latossolo, o tratamento da lixiviaçäo devido à volatilizaçäo foi muito pequeno quando comparado com o retardamento devido à sorçäo:Todos os pesticidas que apresentaram os mais altos potenciais delixiviaçäo foram os mais solúveis em água, com valores do coeficiente de partiçäo (Koc) iguais ou menores que 200 mL/g. Além disso, a meia-vida da maioria destes pesticidas excedeu 30 dias. Os resultados obtidos permitiram estimar que 15,2 por cento do Monocrotofós, 5,7 por cento do Carbofuran e 2,5 por cento do Metalaxil que atinge a superfície do solo ultrapassariam os primeiros 60 cm do perfil do solo, sendo que cerca de 8 mg para cada 100g de Monocrotofós aplicados na superfície do solo passariam através dos primeiros 3m. Com base nos baixos valores de AF calculdados, o potencial de lixiviaçäo dos pesticidas que tem sido usados em áreas agrícolas de Guaíra (SP) sobre latossolos apresenta-se baixo, assim como o consequente risco de contaminaçäo da água subterrânea

Gill lesions in the perch, Anabas testudineus, exposed to monocrotophos.

Histopathological effects of sublethal doses of monocrotophos on the gills have been studied by exposing the fish for a period ranging from ten to twenty days. The extent of damage to gills was dependent on the dose and duration of exposure. Histopathological changes in the gills observed were characterized primarily by hemorrhage in the primary and secondary gill lemellae. Degeneration and necrosis of epithelial cells were very prominent. Distortion of the secondary lamellae was very prominent, beginning with disruption of epithelial cells from pillar cells.

Efficacy of dietary protein in alleviating toxicity of monocrotophos in rats.

Monocrotophos administration at intervals induced variable responses in phosphatases, transaminases and aldolase of liver and plasma. Hepato-toxicity was aggravated under protein deficient state. A weak resistance to toxicity was observed in rats on low protein diet (5%). However, animals fed on protein enriched diet (20%) indicated an elevation in tissue defense mechanism and were able to combat toxic stress of monocrotophos, though partially. A higher protein level may prove efficient and significant for alleviating pesticide toxicity.

Biochemical alterations induced by a new phosphorothionate (RPR-II) in tissues of male and female rats.

This study was conducted to investigate the effect of a new phosphorothionate, the methyl ester of 2-butenoic acid-3-diethoxy phosphinothioyl (RPR-II) on membrane bound target enzymes aspartate amino transferase (ASAT), alanine amino transferase (ALAT) and RBC acetylcholinesterase (AChE) in different tissues of male and female albino wistar rats when treated orally with 0.014 (low), 0.028 (medium) and 0.042 (high) mg/kg daily for a period of 90 days. Repeated administration of RPR-II caused significant increase of ASAT and ALAT enzymes in serum, liver and kidney and significant decrease was recorded in lung in both male and female rats when measured after 45 and 90 days of treatment. This compound also caused significant inhibition of RBC AChE indicating its effect on nerve synapsis. Females were more susceptible than males with regard to ASAT and ALAT levels in serum and liver and also in kidney ASAT, whereas reverse trend was recorded in lung ALAT, suggesting sexual dimorphism in the treated rats. These studies also indicated that the levels of these affected enzymes were recovered to normal conditions after 28 days of post treatment (withdrawal study). Positive correlation was observed with regard to these enzymes between serum, liver and kidney, whereas in case of serum and lung a negative correlation was recorded. These enzymes profile elucidates lung necrosis whereas in other tissues the level of enzymes increased showing an adaptive mechanism due to the chemical stress.

Monocrotofós e estresse: efeitos da exposiçäo pré-natal no desenvolvimento físico e comportamental da prole de ratas / Monocrotophos and stress: effect of prenatal exposure in rats offsring's behavioral and physical development

O presente trabalho propôs-se a estudar os efeitos da exposiçäo pré-natal a dois fatores diversos: ao inseticida organofosforado monocrotofós e ao estresse por contençäo, durante o período organogênico, e evidenciar as possíveis alteraçöes no desenvolvimento físico e comportamental da prole de ratas observadas no período pós-natal. Foram utilizadas ratas Wistar prenhes subdivididas em dois grupos: estressado e näo estressado, que receberam, por gavage, do 6º ao 15º dias da gestaçäo, 1 mg/kg/dia do monocrotofós (tratado) ou água destilada (controle), e que após o parto tiveram suas ninhadas avaliadas quanto ao desenvolvimento físico e comportamental. Durante o período de tratamento as ratas dos grupos estressados (controle e tratado), apresentaram níveis plasmáticos de corticosterona, cerca de 3 vezes mais elevados do que o normal...

Controle da cigarrinha-verde (Empoasca kraemeri (Ross & Moore, 1957) (Hemiptera - Homoptera: cicadellidae)) no feijoeiro (Phaseolus vulgaris) / Control of cigarrinha-verde (Empoasca kraemeri (Ross & Moore, 1957) (Hemiptera - Homoptera: cicadellidae)) in the beans (Phaseolus vulgaris)

Estudou-se os efeitos tóxicos dos inseticidas esfenvalerato, fenitrotion, fenpropatrin e monocrotofos sobre as ninfas de E. kraemeri em cultura de feijoeiro. A pesquisa doi conduzida no município de Nepomuceno - MG, utilizando uma lavoura comerical de cultivar "Carioca". Os compostos foram diluídos em água nas doses recomendadas pelos fabricantes para o controle de pragas, sendo a aplicaçäo realizada através de um pulverizador costal, propiciando volume de aplicaçäo de 400 L/ha. Os resultados mostraram que todos os compostos controlaram a praga em questäo, porém o fenitrotion na dose de 750 g i.a./ha apresentou o maior nível médio de controle.

Studies on the effect of translocation of chemical insecticides in Eicchornia host plant on Mansonia mosquitos--a potential control method.

A novel method for the control of Mansonia larvae was developed and tested. In this method, foliar absorption and translocation of a chemical insecticide, monocrotophos, a known systemic insecticide was studied in the Eicchornia plant. Acetone solution of the insecticide was painted onto leaves of the plant. At daily intervals, stems were severed and divided into equal sections which were introduced into bowls. Larvae of Aedes aegypti were tested for the presence of monocrotophos. It was found that translocation of the insecticide occurred at different rates in the stems and in some plants the chemical was also released into the surrounding water. Based on these results, 2 insecticides namely, monocrotophos and temephos were painted onto leaves of the host plant and their translocation to the root and water environment was examined by testing with Mansonia and Aedes aegypti larvae. The results again confirmed the translocation process and it was found that the insecticides were secreted into the surrounding water, thereby killing the larvae. However, in leaves painted with permethrin (synthetic pyrethroid) or flufenoxuron (chitin synthesis inhibitor), such a process was not detected. The potential of this new concept in Mansonia larval control is examined.