Integrative analysis in toxicological assessment of the insecticide Malathion in Allium cepa L. system / Análise integrativa na avaliação toxicológica do inseticida Malation no sistema Allium cepa L

Abstract For many centuries human populations have been suffering and trying to fight with disease-bearing mosquitoes. Emerging and reemerging diseases such as Dengue, Zika, and Chikungunya affect billions of people around the world and recently has been appealing to control with chemical pesticides. Malathion (MT) is one of the main pesticides used against mosquitoes, the vectors of these diseases. This study aimed to assess cytotoxicity and mutagenicity of the malathion for the bioindicator Allium cepa L. using a multivariate and integrative approach. Moreover, an appendix table was compiled with all available literature of insecticides assessed by the Allium cepa system to support our discussion. Exposures during 48h to 0.5 mg mL-1 and 1.0 mg mL-1 MT were compared to the negative control (distilled water) and positive control (MMS solution at 10 mg L-1). The presence of chromosomal aberrations, micronuclei frequency, and mitotic index abnormalities was evaluated. Anaphase bridges were the alterations with higher incidence and presented a significantly elevated rate in the concentration of 0.5 mg mL-1, including when compared to the positive control. The integrative discriminant analysis summarizes that MT in assessed concentrations presented effects like the positive control, corroborating its potential of toxicity to DNA. Therefore, it is concluded that MT in its pure composition and in realistic concentrations used, has genotoxic potential in the biological assessment of A. cepa cells. The multivariate integrative analysis was fundamental to show a whole response of all data, providing a global view of the effect of MT on DNA.

Resumo Por muitos séculos, as populações humanas sofrem e tentam combater os mosquitos transmissores de doenças. Doenças emergentes e reemergentes como Dengue, Zika e Chikungunya afetam bilhões de pessoas em todo o mundo e, recentemente, vem apelando ao controle com pesticidas químicos. O Malation (MT) é um dos principais pesticidas usados ​​contra mosquitos, vetores dessas doenças. O objetivo deste estudo foi avaliar a citotoxicidade e a mutagenicidade do MT para o bioindicador Allium cepa L. usando uma abordagem multivariada e integrativa. Além disso, uma tabela suplementar foi compilada com toda a literatura disponível de inseticidas avaliada pelo sistema Allium cepa para apoiar nossa discussão. Exposições ao MT durante 48h a 0,5 mg mL-1 e 1,0 mg mL-1 foram comparadas a um controle negativo (água destilada) e um controle positivo (10 mg L-1 de MMS). Foram avaliadas a presença de aberrações cromossômicas, frequência de micronúcleos e anormalidades no índice mitótico. As pontes anafásicas foram as alterações com maior incidência e apresentaram uma taxa significativamente elevada na concentração de 0,5 mg mL-1, inclusive quando comparadas ao controle positivo. A análise discriminante integrativa resume que o MT nas concentrações avaliadas apresentou efeitos semelhantes ao controle positivo, corroborando seu potencial de toxicidade para o DNA. Portanto, conclui-se que o MT, em sua composição pura e nas concentrações realistas utilizadas, possui potencial genotóxico na avaliação biológica de células de A. cepa. A análise integrativa multivariada foi fundamental para mostrar uma resposta completa de todos os dados, fornecendo uma visão global do efeito da MT no DNA.

Carcinogenicidade e mutagenicidade do malathion e seus dois análogos: uma revisão sistemática / Carcinogenicity and mutagenicity of malathion and its two analogues: a systematic review

Resumo O agrotóxico malathion vem sendo amplamente utilizado no mundo em programas de controle de arboviroses e em 2015 foi classificado pela Agência Internacional para Pesquisas em Câncer (IARC) como provável agente carcinogênico para seres humanos. Este trabalho objetivou a sistematização das evidências dos efeitos carcinogênicos e mutagênicos associados à exposição do malathion e seus análogos, malaoxon e isomalathion. A busca foi realizada nas bases de dados TOXLINE, PUBMED e SCOPUS por artigos originais publicados de 1983 a 2015. Do total de 273 artigos elegíveis, foram selecionados 73. Os resultados dos estudos in vitro e in vivo evidenciaram danos genéticos e cromossômicos provocados pelo malathion; os estudos epidemiológicos evidenciaram associações significativamente positivas para cânceres de tireóide, de mama, e ovariano em mulheres na menopausa. Estas evidências do efeito carcinogênico do malathion devem ser considerados diante de sua utilização em programas de controle de arboviroses.

Abstract Malathion has been widely used worldwide in arbovirus control programs. In 2015, it was classified by the International Agency for Research on Cancer (IARC) as a probable carcinogen to humans. This work aimed to systematize the evidence of the carcinogenic and mutagenic effects associated with the exposure of malathion and its analogs, malaoxon and isomalathion. The search was carried out in Toxline, PubMed and Scopus databases for original papers published from 1983 to 2015. In all, 73 papers were selected from a total of 273 eligible papers. The results of in vitro and in vivo studies showed mainly genetic and chromosomal damages caused by malathion. The epidemiological studies evidenced significant positive associations for thyroid, breast, and ovarian cancers in menopausal women. This evidence of the carcinogenic effect of malathion should be considered before its use in arbovirus control programs.

Determination of insecticides' lethal concentrations and metabolic enzyme levels in Triatoma dimidiata / Determinación de concentraciones letales y niveles de enzimas metabólicas de insecticidas en Triatoma dimidiata

Abstract: Objective: The feasibility of the use of WHO impregnated paper and biochemical assays to determine lethal concentrations (LC50 and LC99) and insecticide metabolic enzyme levels of Triatoma dimidiata. Materials and methods: LC50 and LC99 were calculated with WHO papers impregnated at different concentrations of malathion, propoxur and deltamethrin; the percentage of insensitive acetylcholinesterase (iAChE); and the levels of esterases, glutathione S-transferases, and monooxygenases in laboratory nymphs of the first stage (5 to 7 days), were undertaken using the WHO biochemical assays. Results: Respectively the LC50 and LC99 µg/cm2 obtained for malathion were 43.83 and 114.38, propoxur 4.71 and 19.29, and deltamethrin 5.80 and 40.46. A 30% of the population had an iAChE, and only a few individuals had high P450 and β-eterase levels. Conclusion: Impregnated papers and biochemical tests developed by WHO for other insects, proved to be feasible methods in monitoring insecticide resistance and metabolic enzymes involved in T. dimidiata.

Resumen: Objetivo: La factibilidad de usar los papeles impregnados y ensayos bioquímicos según la OMS para determinar concentraciones letales (CL50 y CL99) y niveles enzimáticos en la resistencia a insecticidas en Triatoma dimidiata. Material y métodos: Se calcularon la CL50 y CL99 con papeles impregnados según la OMS a diferentes concentraciones de malatión, propoxur y deltametrina; el porcentaje de acetilcolinesterasa insensible (iAChE); y los niveles de esterasas, glutatión S-transferasas, y monooxigenasas en ninfas de laboratorio del estadio I (5-7 días) se determinaron usando los ensayos bioquímicos según la OMS. Resultados: Se obtuvieron las CL50 y CL99 µg / cm2 respectivamente para malatión 43.83 y 114.38, propoxur 4.71 y 19.29, y deltametrina 5.80 y 40.46. Un 30% de las chinches tuvo iAChE, y sólo pocos individuos tuvieron niveles superiores de P450 y β-eterasas. Conclusión: Los papeles impregnados y ensayos bioquímicos que describe la OMS para otros insectos demostraron ser métodos factibles para monitorear la resistencia a insecticidas y las enzimas metabólicas involucradas en T. dimidiata.

Effects of malathion on cellularity and sperm differentiation in testis and epididymis of adult rats / Efectos del malatión en la celularidad y diferenciación de espermatozoides en testículo y epidídimo de ratas adultas

Malathion is an organophosphorous insecticide, used worldwide for pest and disease control; however, it could also affect the reproductive patterns of several species. The aim of this study was to determine the effects of malathion in the cellularity and sperm differentiation in testis and epididymis of rats. Twenty adult male Sprague Dawley rats were divided into a malathion-treated group (n=10, dose of 170 mg/kg via subcutaneous injection for a period of 13 days) and control group (n=10, injected only with normal saline). After treatments, the rats were sacrificed by regulated euthanasia and assessed for sperm count in testis and epididymis and epididymal teratospermia degree. The results showed a significant decrease in body, testicular and epididymal weight in animals treated with malathion. Testicular sperm counts in treated rats exhibited a significant decrease in the number of sperm compared to controls (42.56x106 vs. 95.99x106), as well as in epididymis (77.55x106 vs. 106.54x106). Concerning the degree of teratospermia, a significant increase of abnormal sperm in the epididymis of treated rats versus controls (42.1% vs. 21%, respectively) was observed. We conclude that malathion has a cytotoxic effect in rats, significantly reducing the number of sperm produced by the seminiferous tubules and affecting their quality and number during the process of maturation and capacitation in their transit through the epididymis, thus increasing the level of teratospermia.

El malatión es un insecticida organofosforado, ampliamente usado en el control de plagas y pestes, sin embargo también puede afectar a los patrones reproductivos de las especies. El objetivo de este trabajo fue determinar los efectos de malatión en la celularidad y diferenciación de espermatozoides en testículo y en epidídimo de ratas. Veinte ratas macho adultas de la cepa Sprague Dawley, fueron divididos en grupo tratado con malatión (n=10) en dosis de 170 mg/kg de peso, inyección sub cutánea (s.c.), por un período de 13 días (duración del ciclo del epitelio seminífero) y grupo control (n=10), los cuales solo fueron inyectados con suero fisiológico. Finalizado el tratamiento las ratas fueron sacrificadas por eutanasia normada y se procedió a medir el recuento espermático en testículo y epidídimo y el grado de teratospermia en epidídimo. Los resultados obtenidos muestran una disminución significativa en el peso corporal, testicular y del epidídimo de ratas machos tratados con malatión. El recuento espermático en testículo de ratas tratadas, al compararlos con ratas controles, muestra una disminución significativa en el número de espermatozoides (42,56x106 / 95,99x106), igual comportamiento se observó en epidídimo (77,55 x106 / 106,54 x106). Al determinar el grado de teratospermia se observó un aumento significativo de espermatozoides anormales, en el epidídimo de las ratas tratadas versus los controles (42,1% y 21%, respectivamente). Se concluye que malatión tiene un efecto citotóxico en ratas, disminuyendo significativamente el número de espermatozoides producidos por los túbulos seminíferos y afectando la calidad y el número de ellos durante el proceso de maduración y capacitación, en su tránsito por el epidídimo, aumentando el nivel de teratospermia.

potential protective and therapeutic effects of aloe vera juice on malathion induced hepatotoxicity in rabbits

the potential protective and therapeutic effects of Aloe vera juice against malathion induced hepatotoxicity were evaluated in this study. one hundred twelve young male rabbits were used ; they were allocated into two sets of experiments included rabbits treated for short [7 days] and long [21 days] periods. Animals of the first set [short period of treatment] were divided into eight groups; each consisted of four treated groups and four control groups [each treated group had its own control]. The animals of the first group were orally dosed with Aloe vera juice [0.84 ml/kg b. wt]. Rabbits of the second group were orally dosed with malathion [5 mg/kg b. wt.]. The third group animals were dosed orally with malathion concomitant with Aloe vera juice [this group served as the protective group]. Animals of the fourth group were dosed orally with malathion; for 7 days followed by Aloe vera juice for the same period [this group served as the therapeutic group]. The design of the second set [long period of treatment] was exactly similar to that of the short period experiments [divided into eight groups; four treated and four control groups] except the duration of treatment which extended to 21 days. Animals of the control groups of Aloe vera treated rabbits were dosed with distilled water, and those of malathion treated animals were dosed with the solvent of the insecticide. All the animals were sacrificed, blood samples were collected and the serum was used to determine the levels of hepatic enzyme markers: lactate dehydrogenase [LDH], aspartate aminotransferase [ASAT], alanine aminotransferase [ALAT] and alkaline phosphatase [ALP] as well as the total bilirubin. the results revealed that treatment of rabbits with malathion caused marked increase in the serum activity of LDH, ASAT, ALAT and ALP in treated rabbits. Administration of Aloe vera juice [in the protective and therapeutic groups] was found to be effective in lowering the elevated activities of these enzymes to approximate near normal levels for both the short and long periods of treatment, especially in the activity of LDH, ASAT and ALP. The present results suggested that Aloe vera juice has ameliorative effects against hepatotoxicity produced by malathion in the treated rabbits

possible protective effect of vitamin C on the kidney cortex of adult female albino rat after chronic exposure to malathion: a light and electron microscopic study

Chronic exposure to malathion is still a major medical problem in occupational and environmental settings. The raised issue of the antioxidants effect on different tissues provides a new line of protection against the inevitable exposure to insecticide residues in food or through environmental contamination. The aim of the study was to determine the effects of vitamin C supplementation on renal cortical tissue after chronic exposure to malathion. Thirty female albino rats aged 3 months were divided into three equal groups: group I control adults were fed the basal diet; group II was given commercial malathion dissolved in distilled water orally by intragastric tube at a dose of 100 mg/kg/day for 2 months; and group III was given malathion in the previously described way at the same dose in addition to vitamin C [pure ascorbic acid powder] dissolved in distilled water and given orally by intragastric tube at a dose of 20 mg/100 g/day for 2 months. The specimens were obtained from the kidney and prepared for light and electron microscopic examinations. Morphometric and statistical studies were carried out in the three studied groups. It was observed that treatment with malathion disrupted the normal histological structure of the renal cortex. Thickened glomerular basement membrane was evident. There was widespread vacuolation of tubular lining epithelium and increased heterochromatin clumps in most of the nuclei. The mitochondria appeared disorganized with loss of cristae. The diameter of renal corpuscles and renal tubules increased, whereas tubular epithelium height decreased significantly compared with the control. Moderate improvement in the previous findings was detected on concomitant supplementation of vitamin C. Vitamin C supplementation played a protective role on the renal cortex exposed to chronic malathion toxicity at the subcellular level

Perfil de suscetibilidade da população de Aedes aegypti (Diptera: Culicidae) da ilha de Santiago, Cabo Verde, a inseticidas / Susceptibility profile of Aedes aegypti from Santiago Island, Cape Verde, to insecticides

Em Cabo Verde, arquipélago situado na Costa Ocidental Africana, os primeiros casos de dengue ocorreram em 2009, com a notificação de mais de 21.000 casos, a maioria desses registrados na Ilha de Santiago. O mosquito Aedes aegypti foi identificado como vetor, e ações para seu controle, usando os inseticidas temephos (larvicida) e a deltametrina (adulticida), têm sido implementadas. Objetiva-se com esse trabalho avaliar o atual status de suscetibilidade a inseticidas e caracterizar os mecanismos de resistência nessa população. Amostras de A. aegypti da ilha de Santiago foram coletadas através de armadilhas de oviposição, para o estabelecimento de uma população a ser analisada. Foram realizados bioensaios do tipo dose diagnóstica, usando garrafas impregnadas com doses únicas dos adulticidas malathion (organofosforado), deltametrina (piretróide) e cipermetrina (piretróide), e bioensaios do tipo dose resposta, usando múltiplas concentrações dos inseticidas temephos (organofosforado), Bacillus thuringiensis sorovariedade israelensis (bactéria entomopatogênica) e diflubenzuron (inibidor de síntese de quitina). Para a investigação dos mecanismos de resistências, foram realizados testes bioquímicos com substratos específicos para quantificar a atividade das enzimas glutationa S-transferases, esterases (alfa, beta e PNPA) e oxidases de função mista, ligadas a detoxificação de xenobióticos, e a taxa de inibição da acetilcolinesterase ligada a insensibilidade do sítio alvo...

Cape Verde, an archipelago located on the West African Coast, recorded the first cases of dengue in 2009 in an epidemic with more than 21,000 reportedcases. The worst affected area was Santiago Island...

Avaliação da dissipação do inseticida malation utilizado em nebulização a ultrabaixo volume no controle da dengue: avaliação ecotoxicológica e de risco ambiental / Evaluation of malathion insecticides dissipation used in ultra-low volume nebulization in dengue control ecotoxicological assessment and environmental risk

A dengue é um dos principais problemas de Saúde Pública da atualidade. É transmitida por mosquitos do gênero Aedes, sendo a espécie Aedes aegypti o vetor responsável pela transmissão no Brasil. O principal alvo de controle da doença é seu vetor, sendo o controle químico amplamente utilizado em todas as regiões atingidas. Como forma de prevenção ou em períodos de epidemia, torna-se necessária a eliminação dos mosquitos adultos, sendo indicada a nebulização a ultrabaixo volume (UBV) a frio do organofosforado malation por meio do uso de equipamentos pulverizadores acoplados a veículos. Este inseticida utilizado pode sofrer desvios durante e após a aplicação a UBV, caracterizando-se como um potencial agente de desequilíbrio ecológico, podendo atingir e gerar efeitos danosos em organismos não alvos aquáticos e terrestres. Este trabalho teve como objetivo desenvolver e validar um método de análise para o malation em cromatografia líquida de alta eficiência e obter recuperação do inseticida em níveis aceitáveis em água e solo, avaliar seu período de dissipação e tempo de meia vida (t1/2) nestas matrizes e classificá-lo quanto à toxicidade aguda e ao risco ambiental de acordo com diferentes autores, para o microcustáceo Daphnia magna, para a minhoca Eisenia foetida, para o peixe mato grosso (Hyphessobrycon eques) e para a macrófita Lemna minor. O método foi considerado adequado para análise do malation. A recuperação obtida para água foi de 97 por cento e para solo, 96 por cento...

Dengue is one of the major public health problems nowadays. It is transmitted by mosquitoes of the genus Aedes, and the Aedes aegypti specie is the vector responsible for transmission in Brazil. The main target to control the disease is its vector, and the chemical control is widely used in all affected regions. As a preventive measure or in epidemic periods, it becomes necessary to eliminate adult mosquitoes, being indicated the ultralow volume nebulization of malathion organophosphate in cold way through the use of sprinklers attached to vehicles. This used insecticide can suffer deviation during and after application ULV, characterizing itself as a potential agent of environmental imbalance, with the possibility of reach and generate harmful effects on aquatic and terrestrial non-target organisms. This work had the objective to develop and validate a method of analysis for malathion in high performance liquid chromatography and obtain recovery of insecticide in acceptable levels in water and soil, evaluate its dissipation period and half-life time in these matrices and classify it on acute toxicity and environmental risk according to different authors, to the microcrustacean Daphnia magna, to the earthworm Eisenia foetida, to the fish Hyphessobrycon eques and to the macrophyte Lemna minor. The method was considered appropriate for analysis of malathion. The obtained recovery for water was 97 per cent and for soil, 96 per cent . Toxic effects resulting from exposure to...

[Toxicity evaluation of malathion, carbaryle and glyphosate in common carp fingerlings [Cyprinus carpio, linnaeus, 1758]]

Common carp [Cyprinus carpio] fishes during release into the rivers estuary of the Caspian southern basin are generally exposed to a broad spectrum of agricultural pesticides. The objective of this study was to investigate the effects of three agricultural pesticides including Malathion, Carbaryle and Glyphosate on C. carpio in lethal level by determining LC[50] 96h and sub-lethal levels via cholinesterase [ChE] activity. The median lethal concentration using a standard method which is called OECD No. 203 [1992], was measured. About 300 fingerlings with average weight of 2.0 +/- 0.4 g were randomly selected and were then exposed to each pesticide in three treatments [0.1, 0.2 LC[50] 96h and negative control] in three replications. 5, 10 and 15 days after the test period, sampling from the head and body of fishes was carried out. The ChE activity was assayed with biochemical method described by Ellman. The LC[50] 96h for three glyphosate, malathion and carbaryle pesticides were obtained as 6.75, 1.3 and 12.67 mg/L, respectively. The mean values of ChE for both head and body under control conditions were found 1241.356 and 723.103 mU/min/mg protein, respectively. Therefore, the ChE activity of head was 1.7 times more than the body. During the test period, inhibition activitiy of ChE was significantly observed in the fishes treated by any of three components in comparison with control [p<0.05]. The ChE inhibition potential by carbaryle and glyphosate was lower than malathion as compared with control. The exposure time concentration exhibited a significant effect compared to the fishes treated by the investigated pesticide types. The used pesticide concentrations for non-target species which were ineffective and permissible according to the lethality bioassay test can lead to their enzyme responses and bio-damages

Malathion Affects Spermatogenic Proliferation in Mouse / Malathion Afecta la Proliferación Espermatogénica del Ratón

The restriction of the mechanisms of cell proliferation in murine seminiferous epithelium, in terms of induction of programmed cell death until recently has not been fully analyzed. The aim of this work was to assess the effect of Malathion (MP) on testicular morphology and function in mouse spermatogenesis. For the experiments, male albino mice of strain NMRI-IVIC, weighing between 30-40 g were used, and divided into control and experimental groups of 5 each. The animals of the experimental groups were injected with a single dose of MP: 241mg/kg weight (1/12 LD 50 ) resuspended in 0.9% saline, intraperitoneally. Animals were sacrificed at 8.3, 16.6 and 33.2 days post-injection (first, second and third spermatogenic cycles). Testicular samples were obtained for light microscopy (LM), transmission electron microscopy procedures, and to detect apoptosis and p53 antigen by immunohistochemical methods. Blood was collected to quantify testosterone and plasmatic cholinesterase activity. From 8.3 days, Sertoli cell vacuolization, karyolisis of pachytene spermatocytes and Leydig cells and a decreased in average of the diameter of seminiferous tubules was observed. No damage to inter-Sertoli cells junctions was detected. Percentage of seminiferous tubules showing germ cells apoptosis was increased from 8.3 days, plasmatic acetylcholinesterase activity was reduced in the group treated only 24 hours after administration of MP. Serum testosterone levels were low in treated animals at 16. 6 and 33.2 days. p53 was mostly expressed in pachytene spermatocytes from 8d. The findings of this study indicate that MP alters the testicular function affecting the DNA and interfering with spermatogenesis as well as steroidogenesis.

La restricción de los mecanismos de proliferación celular en epitelio seminífero murino, en términos de inducción de muerte celular programada hasta hace poco no había sido completamente analizada.El objetivo de este trabajo fue evaluar el efecto de malathion (MP) sobre la morfología y la función testicular del ratón.Ratones macho albinos de la cepa NMRI-IVIC, con pesos entre 30-40 g fueron utilizados, se dividieron en grupos control y experimental. Los grupos experimentales fueron inyectados por vía intraperitoneal con una dosis única deMP:241mg/kg de peso (1/12 DL50) resuspendido en 0,9% de solución salina.Los animales fueron sacrificados en el día 8,3, 16,6 y 33,2 después de la inyección (primer, segundo y tercer ciclos de la espermatogénesis).Se obtuvieron muestras de testículo para estudio en microscopía de luz (ML), microscopía electrónica de transmisión, para la detección de apoptosis y el antígeno p53 (proliferación celular), por métodos inmunohistoquímicos.Se recogió sangre para cuantificar la testosterona y la actividad plasmática de colinesterasa.Desde el día 8,3 día se observó vacuolización de células de Sertoli, cariolisis de espermatocitos en paquiteno y células de Leydig, y una disminución en el promedio del diámetro de los túbulos seminíferos. No se detectó daño en las uniones entre células de Sertoli. El porcentaje de túbulos seminíferos que mostraban células germinales en apoptosis se incrementó a los 8,3 días, laactividad de la acetilcolinesterasa plasmática se redujo en el grupo tratado sólo 24 horas después de la administración de MP.Los niveles séricos de testosterona disminuyeron en los animales tratados a los 16,6 y 33,2 días.P53 se expresó sobre todo en los espermatocitos en paquiteno desde los 8,3 días.Los resultados de este estudio indican que MP altera la función testicular, afecta al ADN e interfiere con la espermatogénesis, así como con la esteroidogénesis.

Persistence of DDT, malathion & deltamethrin resistance in Anopheles culicifacies after their sequential withdrawal from indoor residual spraying in Surat district, India.

Background & objectives: Under the national antimalaria programme DDT was introduced in early 1950s for vector control and later hexachloro cyclohexane (HCH) followed by malathion and recently synthetic pyrethroids in 1990s to manage the insecticide resistance in Anopheles culicifacies. Subsequent replacement led to development of multiple resistances in An. culicifacies in Surat district in Gujarat State. Indoor residual spray (IRS) was completely withdrawn in southern villages in Surat in 2002. This study was undertaken in these areas to study the persistence of resistance to DDT, malathion and deltamethrin after sequential withdrawal of IRS with these insecticides at different times. Methods: Susceptibility tests on An. culicifacies were conducted using standard WHO methods and kits. Mortality, knockdown time and lethal times were calculated for An. culicifacies exposed to WHO prescribed diagnostic concentrations of different insecticide impregnated papers. Results: Persistence of DDT-resistance was observed even after 30 yr of its withdrawal from IRS. Similarly, persistence of malathion resistance was also observed after 9 yr of its withdrawal from IRS, while reversal of deltamethrin-resistance was observed very fast within 2-3 yr after its withdrawal from IRS in 2002. Interpretation & conclusion: Present data indicate that the quantum of reversion of insecticide resistance in a population is relative and depends on the genetic stability of the respective resistance genes in the mosquitoes. In the present study withdrawal of pyrethroid-IRS resulted in increased susceptibility against pyrethroids alone and was independent of existence of resistance to insecticides of other groups. This study emphasizes that appropriate rotation of different insecticides; including carbamates may prevent or delay the onset of resistance.

Análisis morfométrico de los túbulos testiculares del ratón después de la administración de malation y maca / Morphometric analysis of mice testicular tubules after administration of malathion and maca

Los agropesticidas organofosforados (OF) son ampliamente usados para incrementar la producción alimentaría. Sin embargo, se ha demostrado que inducen alteraciones a nivel testicular, relacionadas con la disminución de la fertilidad tanto en humanos como en animales. Por otra parte, diferentes estudios han sido llevados a cabo para desarrollar compuestos químicos o naturales que puedan inducir un efecto antagónico sobre los OF. En estudios anteriores, un extracto de una planta de los Andes peruanos (Maca) ha sido reconocido por su acción estimulante sobre la espermatogénesis. En el presente trabajo se estudiaron los efectos de ambos agentes externos sobre el testículo. Una población de 52 ratones machos adultos de la cepa CF1 fue dividida al azar en 4 grupos (Control, Malation, Maca, Malation-Maca), con intervalos de sacrificio de 1, 7, 14 y 21 días. Para analizar el grado de alteración inducida por estos agentes, se utilizaron técnicas de histomorfometría con ayuda del programa Image tools 3.1, en secciones testiculares. Nuestros resultados muestran que la altura del epitelio aumentó al día 1 en el grupo tratado con malation, cayendo al día 7 y llegando a valores similares al control, al día 14. Sin embargo, el grupo Malation-Maca no mostró cambios significativos. El lumen tubular, disminuyó al día 7 y 14, para normalizarse al día 21 en el grupo Malation. Sin embargo, en el grupo Malation-Maca el lumen tubular sólo bajó al día 14. El diámetro tubular disminuyó a los días 7 (p < 0.01), 14 y 21 en el grupo Malation, con respecto al control (p< 0.05). Sin embargo, el grupo Malation-Maca mostró valores normales. En conclusión, es posible establecer que el daño inducido por Malation es revertido al día 21 post administración de maca.

Organophosphoric (OP) agropesticidas are amply used to increase food production. However, it has been verified that they induce alterations at testicular level related to the diminution of fertility in humans as in animals. On the other hand, different studies have been made to develop chemical or natural compounds that can induce an antagonistic effect to OP. In previous studies an extract from a plant, from the Peruvian Andes (Maca) has been recognized by its stimulating action on spermatogenesis. In the present study the effects of both external agents were evaluated on testicular sections of testis of adult male mice on a population of 52 mice CF1, divided at random in 4 groups (Control, Malathion, Maca, Malathion-Maca), with sacrifice intervals of 1,7, 14 and 21 days. By means of morphometric technique and using the "Image Tools 3,1" software, the histology of testicular sections was evaluated, to analyze the degree of alteration induced by these agents. The epithelial height mainly has a rise in day 1, for Malathion group and then fall to day 7 to be normal by day 14. However, Malathion-Maca groups show no changes. The tubular lumen decreases at day 7 and day 14 to be normal by day 21 in Malathion group. However, in Malathion - Maca group, the tubular lumen decreases only at 14 days. The tubular diameter, at day 7 (p<0.01), 14 and 21 in Malathion group decreases respect to control (p<0.05), However, Malathion-Maca groups show normal values. In conclusion, it is possible to establish that the damage induced by Malathion is reverted by 21 days post-administration of Maca.

Impact of malathion on the biochemical parameters of gobiid fish, Glossogobius giuris (Ham).

There is a dearth of information regarding the changes in heart muscle metabolites induced by pesticides. In the present study, the gobiid fish, Glossogobius giuris, was exposed to sub lethal concentrations of (0.05, 0.25 and 0.5 ppm) organophosphorus pesticide, malathion for short duration (24 to 96 hr). The cardiac muscles showed maximum depletion of glycogen and cholesterol content during 72 and 96 hr after treatment with 0.5 ppm malathion. Whereas a slight fluctuation of protein and glycogen content was observed in low concentration (0.05 ppm) of malathion. The levels of protein showed a significant decrease at high concentration (0.5 ppm) when treated for longer duration (96 hr). The present study reports metabolic dysfunction in response to malathion toxicity in the fish.

Comparative toxicity of malathion and its metabolite Alhpa-[O,O-Dimethyl phosphorodithio] propionic acid ethyl ester towards mice

The organophosphorus insecticide malathion [I] and its metabolite alpha-[O, O-dimethyl phosphorodithio] propionic acid ethyl ester [II] have been tested for their acute and subacute oral toxicity in mice. The oral LD50 values were determined to be 900 and 820 mg/kg, for malathion and its metabolite, respectively. Administration of both compounds to mice with one fifth and one tenth of their calculated oral LD50 for two weeks led to a significant depression of blood and brain cholinesterase activity in all treated groups. The maximum inhibition for brain cholinesterase activity [36-47%] and plasma [40-51%] was observed after 10 days of treatment. All treated mice returned to their normal statement after one week recovery period. Both compounds proved to have comparable toxicity towards mice

Efectos del malatión sobre la reorganización nuclear en el epitelio de duodeno: presencia de microcuerpos cromatínicos citoplasmáticos / Effects of the malathion on the nuclear reorganization in the duodenal epithelium: presence of cytoplasmic chromatinic microbodies

El Malatión es un pesticida organofosforado ampliamente utilizado en agricultura, pero que en los mamíferos y el ser humano tiene un efecto altamente tóxico, inhibiendo la acetilcolinesterasa (AChE). Además, tiene la potencialidad de alterar el ciclo celular y de producir distorsiones a nivel de replicación y síntesis del DNA celular. El presente estudio tiene como objetivo describir el efecto de Malatión sobre las células del epitelio intestinal, mediante la detección de micronúcleos o cuerpos cromatínicos, con expresión que se traduce en toxicidad y genotoxicidad celular. Se utilizaron 6 ratas machos de laboratorio Sprague Dowley, las cuales fueron divididas en dos grupos de 3 individuos cada uno: (1) experimental y (2) control. Al grupo experimental se les administró una dosis de 170 mg/kg peso corporal de Malatión, por vía subcutánea, por un período de 13 días. En las preparaciones histológicas de duodeno del grupo control, se observó un epitelio intestinal normal, mientras que en el de las ratas tratadas con Malatión, se encontró la presencia de micronúcleos cromatínicos (MC) o estructuras picnóticas en el citoplasma, aproximadamente en el 80 por ciento de las células. Estos hallazgos permiten concluir que la administración de Malatión altera en forma evidente la histología del epitelio intestinal en las aratas expuestas al pesticida.

Mice testicular damage elicited by malathion

Organophosphorous pesticides are a healh problem worldwide, mostly for agroworkers, which are around 2600 millions of person in the year 2001. Little is known about male reproductive damage elicited by these chemicals. The acute effects of malathion (single intraperitoneal injection), 1/12 the LD50 to mice were analyzed at 1, 8, 16, 35 and 40 days after injection, in terms of spermatogenic cell proliferation and apoptosis and of Sertoli cell compromise as revealed by immunocytochemical detection of CK-18 (cytokeratin). The micronuclei test was done to assess for genotoxic activity of the agropesticide. The results showed decreased germ cell number followed by compensatory spermatogonial proliferation by 16 days (as shown by thymidine-H3 testicular uptake), increased apoptotic rate, mainly of spermatogonia, and preleptotene spermatocytes. Sertoli cell reactivity to CK-18, denoting alteration of them, probably due to germ cell damage, was seen in treated mice. Genotoxicity for somatic cells was demonstrated by the micronuclei test. Therefore, it is assumed that Sertoli as well as Leydig cells are affected together with spermatogenesis; recuperation of testicular morphology is seen by longer time intervals.

A comparative evaluation of immunotoxicity of malathion after subchronic exposure in experimental animals.

The effects of sub-chronic doses of malathion exposure on humoral and cell-mediated immune (CMI) responses were studied in male albino mice, rats and rabbits using sheep red blood cells (SRBC), tetanus toxoid and ovalbumin as antigens. The humoral immune response was assessed by estimating serum immunoglobulin (IgM and IgG) concentrations, antibody titre against antigens and splenic-plaque forming cells (PFC). The CMI response was studied by using the leucocyte migration inhibition (LMI) and macrophage migration inhibition (MMI) tests. In general there were (a) attenuation in antigen induced antibody response, (b) suppression of PFC, and (c) marked inhibition of LMI and MMI factors. Sub-chronic malathion exposure induced differential degrees of humoral and CMI suppression in these experimental animals. However, both cellular and humoral immune responses were decreased in a dose-time dependent pattern and a consistent trend was observed. The threshold level of the malathion for inducing immune suppression depends on the animal species, type of antigen used, and the method of immunological assay. In view of the widespread use of malathion a comparative assessment of immune responses using different experimental animals and antigens is an important aspect of its safety evaluation.

Impact of protein deficiency and exposure to hexachlorocyclohexane or malathion on lipid metabolism in pregnant rats.

Dietary intake of three oral doses of hexachlorocyclohexane (HCH) (60 mg/kg body wt) or malathion (500 mg/kg) by normal and protein-deficient diet fed pregnant rats on the 6th, 10th and 14th day of gestation resulted in the impairment of lipid metabolism, viz. hypercholesterolemia and hypertriglyceridemia. The cholesterol, triglyceride and phospholipid contents in serum, brain, liver, kidney and uterus were increased significantly by HCH and malathion exposure, irrespective of the protein content in the diet. The incorporation of [1,2-14C]acetate into the hepatic lipids was stimulated by both HCH and malathion, suggesting a higher rate of lipid synthesis in the liver of normal and protein-deficient diet fed dams. The low protein content in the diet intensified the pesticide-induced changes and more severe alterations were noticed in HCH exposed dams than in malathion exposed dams.

Activity of four organophosphorus insecticides in the mouse sperm morphology test

O efeito de 4 inseticidas organofosforados (malation, diazinon, diclorvos e triclorfon) foi avaliado em camundongos, através do teste de morfologia de espermatozóide. Os animais foram expostos aos inseticidas, por via intraperitoneal (diazinon, diclorvos e triclorfon), via dérmica (malation) e por inalaçäo (diclorvos) durante 5 dias consecutivos. Um aumento significativo na frequência de espermatozóides anômalos foi observado quando os animais foram expostos ao malation (1000 mg/Kg) ao diazinon (100 mg/Kg) e ao diclorvos, por inalaçäo (0,24 e 0,32 mg/l). Contudo, nenhum aumento significativo foi observado com relaçäo ao triclorfon e ao diclorvos quando os animais foram expostos pro via intraperitoneal