Carbaryl degradation by bacterial isolates from a soil ecosystem of the Gaza Strip

Abstract Carbaryl is an important and widely used insecticide that pollutes soil and water systems. Bacteria from the local soil ecosystem of the Gaza Strip capable of utilizing carbaryl as the sole source of carbon and nitrogen were isolated and identified as belonging to Bacillus, Morganella, Pseudomonas, Aeromonas and Corynebacterium genera. Carbaryl biodegradation by Bacillus, Morganella and Corynebacterium isolates was analyzed in minimal liquid media supplemented with carbaryl as the only source of carbon and nitrogen. Bacillus and Morganella exhibited 94.6% and 87.3% carbaryl degradation, respectively, while Corynebacterium showed only moderate carbaryl degradation at 48.8%. These results indicate that bacterial isolates from a local soil ecosystem in the Gaza Strip are able to degrade carbaryl and can be used to decrease the risk of environmental contamination by this insecticide.

Reduced expression of exocytotic proteins caused by anti-cholinesterase pesticides in Brachionus calyciflorus (Rotifera: Monogononta) / Redução da expressão de proteínas de exocitose causados por pesticidas anti-colinesterase em Brachionus calyciflorus (Rotifera: Monogononta)

AbstractThe organophosphate and carbamate pesticides methyl-parathion and carbaryl have a common action mechanism: they inhibit acetylcholinesterase enzyme by blocking the transmission of nerve impulses. However, they can alter the expression of exocytotic membrane proteins (SNARE), by modifying release of neurotransmitters and other substances. This study evaluated the adverse effects of the pesticides methyl-parathion and carbaryl on expression of SNARE proteins: Syntaxin-1, Syntaxin-4 and SNAP-23 in freshwater rotifer Brachionus calyciflorus. Protein expression of these three proteins was analyzed before and after exposure to these two pesticides by Western Blot. The expression of Syntaxin-1, Syntaxin-4 and SNAP-23 proteins in B. calyciflorussignificantly decreases with increasing concentration of either pesticides. This suggests that organophosphates and carbamates have adverse effects on expression of membrane proteins of exocytosis by altering the recognition, docking and fusion of presynaptic and vesicular membranes involved in exocytosis of neurotransmitters. Our results demonstrate that the neurotoxic effect of anticholinesterase pesticides influences the interaction of syntaxins and SNAP-25 and the proper assembly of the SNARE complex.

ResumoOs pesticidas organofosforados e carbamatos metil- paration e carbaril tem um mecanismo de ação comum: eles inibem a enzima acetilcolinesterase, bloqueando a transmissão dos impulsos nervosos. No entanto, eles podem alterar a expressão de proteínas de membrana de exocitose (SNARE), através da modificação da libertação de neurotransmissores e outras substâncias. Este estudo avaliou os efeitos adversos dos pesticidas metil- paration e carbaril sobre a expressão de proteínas SNARE: Sintaxina -1, Sintaxina-4 e SNAP-23 em rotíferos de água doce Brachionus calyciflorus. A expressão destas três proteínas foi analisada antes e depois da exposição a estes dois pesticidas por Western Blot. A expressão das proteínas Sintaxina-1, Sintaxina-4 e SNAP-23 em B. calyciflorus diminui significativamente com o aumento da concentração de ambos os pesticidas. Isto sugere que os organofosfatos e carbamatos têm efeitos adversos sobre a expressão de proteínas de membrana de exocitose, alterando o reconhecimento, de encaixe e fusão de membranas pré-sinápticas e vesiculares envolvidas na exocitose de neurotransmissores. Nossos resultados demonstram que o efeito neurotóxico de pesticidas anticolinesterásicos influencia a interação de sintaxinas e SNAP-25 e a montagem correta do complexo SNARE.

Avaliação de melanócitos humanos expostos ao inseticida carbaril e à radiação solar em cultura / Evaluation of cultured human melanocytes exposed to carbaryl insecticide and solar radiation

O carbaril (metilcarbamato de naftila), um inseticida de amplo espectro, foi recentemente associado ao desenvolvimento de melanoma cutâneo em estudo epidemiológico de coorte com trabalhadores agrícolas norte-americanos, expostos também à radiação solar, o principal fator etiológico para o desenvolvimento de tumores cutâneos. Apesar de abrangente e bem planejado, aquele estudo epidemiológico não é suficiente para caracterizar a contribuição direta do inseticida e da radiação solar na melanomagênese. Diversos estudos têm explorado o efeito sinérgico de determinadas substâncias químicas à radiação UV, potencializando seus efeitos deletérios sobre a pele, e possivelmente contribuindo para o desenvolvimento de tumores. A hipótese deste trabalho é de que a exposição ao carbaril associada à radiação solar possa estimular a transformação de melanócitos. Esse estudo visou caracterizar melanócitos humanos após exposição individual ou combinada ao carbaril (100uM) e à radiação solar (375 mJ/ cm2). Em ensaio de microarray, o carbaril, mas não a radiação solar, induziu uma importante resposta a estresse oxidativo, evidenciada pelo aumento da expressão de genes antioxidantes, como o Hemeoxigenase-1 (HMOX1), e pela diminuição da expressão do gene MiTF, regulador da atividade melanocítica; os resultados foram confirmados por qRT-PCR. Além disso, tanto o carbaril quanto a radiação solar induziram respostas que sugerem dano ao DNA e alteração de ciclo celular. A expressão dos genes nestas categorias, como p21 e BRCA1/2, foi notavelmente mais intensa no grupo de tratamento combinado e de fato, ensaios por citometria de fluxo demonstraram parada de ciclo celular na fase S, redução do número de células em apoptose e indução mais rápida de lesões do tipo CPD neste grupo experimental. Nossos dados sugerem que o carbaril é genotóxico para melanócitos humanos, especialmente quando associado à radiação solar

Carbaryl (1-naphthyl-methylcarbamate), a broad spectrum insecticide, has recently been associated with the development of cutaneous melanoma in an epidemiological cohort study with U.S. farm workers also exposed to ultraviolet radiation, which is known to be the main etiologic factor for skin carcinogenesis. Although comprehensive and well designed, the epidemiological study is not sufficient to characterize the direct contribution of the insecticide and solar radiation in melanomagenesis. Several studies have explored the synergistic effect of certain chemicals with UV radiation, increasing its deleterious effects on the skin, possibly contributing to tumor development. We hypothesized that Carbaryl exposure associated with UV solar radiation may induce melanocyte transformation. This study aims to characterize human melanocytes after individual or combined exposure to Carbaryl (100uM) and solar radiation (375 mJ/ cm2). In a microarray analysis, Carbaryl, but not solar radiation, induced an important oxidative stress response, evidenced by the upregulation of antioxidant genes, such as Hemeoxygenase-1 (HMOX1), and downregulation of MiTF, the main regulator of melanocytic activity; results were confirmed by qRT-PCR. Moreover, both Carbaryl and solar UV induced a gene response that suggests DNA damage and cell cycle alteration. The expression of genes in these categories, such as p21 and BRCA1/2, was notably more intense in the combined treatment group in an additive manner and in fact, flow cytometry assays demonstrated cell cycle arrest in S phase, reduced apoptosis induction and faster induction of CPD lesions in this experimental group. Our data suggests that carbaryl is genotoxic to human melanocytes, especially when associated with solar radiation

[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

[Comparison of PBO and DEF effects on creating bendiocarb and carbaryl insecticide resistance in German cockroach]

German cockroach [Blattella germanica, Blattodea:Blattellidae] is considered one of the common pests in hospitals, hotels, households and dormitories which can transfer different pathogenic fungi, viruses and bacteria. The aim of this study was to determine the resistance mechanisms to bendiocarb and carbaryl in German cockroache, in vivo. In this study, German cockroach strains were collected from several hospitals and dormitories in Tehran and transferred to insectarium. The strains were reared under the same laboratory conditions. At first the discriminative doses of bendiocarb and carbaryl were determined by surface contact method. Then the susceptibility level and types of resistance mechanisms to bendiocarb and carbaryl, in the strains were studied by using PBO and DEF as synergists. Simultaneous use of DEF as synergist, with bendiocarb and carbaryl led to the breakdown of resistance in all strains. But use of PBO instead of DEF did not overcome the resistance in the strains collected from Mofid, Alvand and Vali Asr hospitals and Shariati dormitory. In general, the effect of DEF in breaking the resistance was more than that of PBO. Complete breakdown of resistance after simultaneous use of DEF with bendiocarb and carbaryl insecticides, indicated the essential role of esterase enzymes in producing resistance to bendiocarb and carbaryl in the strains. But PBO did not break the resistance completely in most wild strains, which may be due to other possible mechanisms of resistance such as reduction of cuticle penetration or insensitivity to acetyl cholinesterase enzyme

Evaluación de riesgo por plaguicidas sobre aguas superficiales de la región norpatagónica argentina / Assessing pesticide hazards on surface water from the northern patagonian region argentina

Aunque el manejo integrado de plagas se aplica en forma creciente en la Región Norpatagónica, todavía una amplia gama de plaguicidas es utilizada con el fin de controlar apropiadamente las principales plagas agrícolas. Otros agroquímicos también son aplicados en las actividades industriales asociadas. El objetivo del presente trabajo es evaluar el impacto potencial causado por estos plaguicidas sobre los organismos acuáticos y para ello se utilizan datos bibliográficos de toxicidad aguda y resultados analíticos locales. Se utilizó un procedimiento escalonado, permitiendo la selección de aquellos xenobióticos ambientales que justificarían un estudio de ecotoxicidad posterior. Los residuos máximos de metil azinfos (S-(3,4-dihydro-4-oxobenzo[d]-[1,2,3]-triazin-3-ylmethyl)O,O-dimethyl phosphordithioate), indican la probabilidad de efectos agudos en el 37% de las especies estudiadas en el río, principalmente peces y zooplancton. Este valor se incrementa en los drenajes hasta un 42%. En el caso del carbaril (1-napthylmethylcarbamate) los residuos encontrados en drenajes afectarían al 14% de las especies estudiadas, mientras que en el río el impacto es despreciable.

Although the Integrated Pest Management (IPM) is increasingly being applied in the Northern Patagonia Region, different pesticides are still used in order to properly control agricultural pests. Other agrochemicals are also applied in the agriculture associated activities like conservation and packaging industries. The potential impact caused by these pesticides on aquatic organisms is assessed in the present study by means of acute toxicity data available in the literature and local analytical results. A tiered procedure was used allowing the selection of those environmental xenobiotics that need further ecotoxicity studies. The observed maximum residues of azinphos-methyl, (S-(3,4-dihydro-4-oxobenzo[d]-[1,2,3]-triazin-3-ylmethyl) O,O-dimethyl phosphordithioate), indicate the probability of acute effects in 37 % of the studied species in the river, mainly fish and zooplankton.This value increased in drainage channels samples up to 42 %. Additionally, carbaryl (1-napthylmethylcarbamate) residues foundin drainage channels affect 14 % of the studied species, while in the river samples the impact was negligible.

Immunotoxicity of carbaryl in chicken.

Effect of methyl carbonate pesticide, carbonyl, was studied on macrophage functions, lymphocyte proliferation and delayed type hypersensitivity response. Sixteen adult chicken, vaccinated against Newcaslte disease, were procured and randomly divided in two experimental groups. Chicken of group I served as control, while group II birds were given carbaryl at 20 ppm (No observable effect level, NOEL) in feed for 3 months. To measure the functional activity of phagocytic cells, nitroblue tetrazolium (NBT) reduction test was performed on peripheral blood leucocytes. Concanvalin A (Con-A) and lipopolysaccharide stimulated proliferation of T and B lymphocytes was assessed using MTT dye method. At the end of experiment, the phagocytic capacities of macrophages were significantly reduced in carbaryl treated group. Lymphocyte proliferation responses to Con-A and LPS were (23 and 28%, respectively lower) in chicken fed with carbaryl. Delayed hypersensitivity reaction to tuberculin was reduced to 77% of control values indicating inhibition of cell mediated immune response. The present study suggested of immunosuppressive effect of (NOEL dose carbaryl) in chicken.

Biossensor amperométrico para detecção screening de inseticidas carbamatos em águas de abastecimento / Amperometric biosensor to detect screening of carbamate insecticides in drinking water

Biossensor amperométrico, baseado em enzimas colinesterases (AChE) imobilizadas em eletrodo do tipo screen-printing, foi utilizados na investigação de teores de pesticidas carbamatos (carbofuran e carbaril) em amostras de águas de abastecimento. Inicialmente, efetuou-se o estudo dos constantes de inibição dos pesticidas carbaril (1x10 elevado à sétima potência) e carbofuran (5x10 elevado à quarta potência). Utilizou-se sistema com eletrodo de dois canais, composto de grafite modificada com TCNQ e Ag/AgCl, como eletrodos de trabalho e referência, respectivamente. Dois processos, visando otimização do biossensor. A metodologia de fotopolimerização com álcool polivinílico modificado com grupos estirilpiridínicos (PVS-SbQ) e a de glutaraldeido foram selecionadas para o estudo, sendo que a imobilização com PVS-SbQ apresentou melhores resultados (CV=6,5por cento). Curvas analíticas foram plotadas após os ensaios de inibição com os pesticidas e os limites de detecção (LD) determinados. Carbaril apresentou curva linear (LD de 18 ug L -1), enquanto o carbofuran demonstrou curva com comportamento logarítmico (LD de 0,05 ug L-1). Para avaliar a precisão, amostras de água de abastecimento foram fortificadas com os pesticidas estudados em três níveis de fortificação. As recuperações variaram de 93,3 por cento a 102,7 por cento. Os biossensores a base de AChE atenderam às exigências analíticas para a direta aplicação de sensores descartáveis em amostras reais

Effects of carbaryl production exposure on the sperm and semen quality of occupational male workers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To analyse the male reproductive toxicity of carbaryl.</p><p><b>METHODS</b>Thirty-one male carbaryl exposure workers and 46 male administrators in the office in a pesticide factory were selected as the exposure group and internal control group respectively, and 22 male administrators in a center for disease control and prevention were served as the external control group. In order to evaluate the exposure levels, the concentrations of carbaryl, methyl isocyanate, ammonia and phenol in the ambient air of the work place in these three groups were monitored simultaneously for three consecutive days. Moreover, three workers in the exposure group and the external control group were selected to evaluate the amount of carbaryl of individual and dermal contamination for three consecutive days. After the semen were collected according to the standard method, the workers'semen qualities were analysed with WHO method, the sperm morphology and the sperm motility were evaluated using micro-cell slide spectrum technology and computer assisted sperm analysis (CASA) respectively.</p><p><b>RESULTS</b>In the exposure group, the concentrations of carbaryl and phenol (52.41 mg/m(3) and 0.08 mg/m(3) respectively) were significantly higher than those in the internal and external control group (P < 0.01 or P < 0.05). Furthermore, in the carbaryl exposure area the geometric mean concentration of carbaryl with the individual sampling was 7.38 mg/m(3), and the geometric mean of dermal contamination detected in the carbaryl exposure area was 862.47 mg/m(2). Carbaryl was not found in the external control area (P < 0.01). The seminal volume [(2.39 +/- 1.44) ml] and the sperm motility [(1.77 +/- 0.61) grade] were significantly lower than those in the external control group (P < 0.05), and sperm motion parameters such as linearity (LIN, 39.89% +/- 6.00%), straightness (STR, 71.51% +/- 11.22%), straight line velocity [VSL, (26.29 +/- 7.84) microm/s] and beat cross frequency [BCF, (3.99 +/- 1.55) Hz] were lower than those in the internal and external control group (P < 0.05), while the abnormal rates of viscidity, sperm motility and total aberration rate were higher than those in the external control group (P < 0.05).</p><p><b>CONCLUSION</b>Occupational exposure to carbaryl production can affect the workers'sperm and semen quality to certain extent.</p>

Effects of carbaryl on serum steroid hormone and the function of antioxidant system in female rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of carbaryl on serum steroid hormone and function of antioxidant system in female Sprague Dawley rats.</p><p><b>METHODS</b>Carbaryl was administrated to the adult female rats at doses of 0, 1.028, 5.140 and 25.704 mg x kg(-1) x d(-1) for 30 d. Vaginal smears of rats were taken to determine estrous cycle. Serum 17beta-estradiol (E(2)) and progesterone (P(4)) concentrations were measured by radioimmunoassay. The activities of superoxide dismutase (SOD) and glutathione-s-transferase (GST), and the levels of malondialdehyde (MDA) and glutathione (GSH) were measured by spectrophotometry.</p><p><b>RESULTS</b>The number of estrous cycle in exposed groups were obviously lower than in control group (P < 0.05, P < 0.01). Body weight gain in high dose group (25.704 mg x kg(-1) x d(-1)) was significantly lower than that in control. Meanwhile, the organ coefficient of ovary and uterus declined in a dose-dependent manner. Serum E(2) level [(19.93 +/- 2.21) nmol/L] in 25.704 mg group was lower than in control group [(28.76 +/- 6.12) nmol/L, P < 0.05], and P(4) level (1.21 +/- 0.40) nmol/L in 1.028 mg group was higher than that in control group [(0.63 +/- 0.39) nmol/L, P < 0.05]. The activity of SOD first reduced then rose in ovary, and first rose then reduced in serum. The contents of MDA increased in ovary, while decreased in the serum. GSH contents and GST activity increased in ovary, while in serum GSH contents decreased and GST activity first increased then decreased.</p><p><b>CONCLUSION</b>Carbaryl could disrupt estrous cycle and affect serum steroid hormone, and the function of antioxidant system in female SD rats.</p>

Validation of an electrometric blood cholinesterase measurement in goats

A modified electrometric method was described and validated for measurement of plasma and erythrocyte cholinesterase activities in 6~18 months old goats. The enzymatic reaction mixture contained 3 ml distilled water, 3 ml barbital-phosphate buffer (pH 8.1), 0.2 ml plasma or erythrocytes and 0.1 ml acetylthiocholine iodide (7.5%) as a substrate. The mixture was incubated at 37 degrees C for 40 minutes. The pH of the reaction mixture was determined by a pH meter before and after the incubation. The initial pH was measured before the substrate addition. The enzyme activity was expressed as deltapH/40 min. The coefficients of variation of the described method in measuring plasma and erythrocyte cholinesterase activities were 4 and 2%, respectively. Preliminary reference values (n = 14) of the mean cholinesterase activity (deltapH/40 min) and 95% confidence interval in the plasma were 0.194 and 0.184~ 0.204, respectively, and those of the erythrocytes were 0.416 and 0.396~0.436, respectively. The pseudocholinesterase activity of the plasma cholinesterase was 63.5% as determined by quinidine sulfate inhibition. The organophosphorus insecticides dichlorvos and diazinon at 0.5~4 micrometer and the carbamate insecticide carbaryl at 5~20 micrometer in the reaction mixture significantly inhibited plasma (13.7~85.5%) and erythrocyte (16.4~71.9%) cholinesterases in vitro in a concentration-dependent manner. The results suggest that the described electrometric method is simple, precise and efficient in measuring blood cholinesterase activity in goats.

Study of Serum Cholinesterase levels in fish Clarias batrachus (Linn.) exposed to pesticides carbaryl and phorate.

Study of the Serum Cholinesterase levels (SchE) in the freshwater catfish Clarias batrachus when exposed to sub lethal dose of pesticides phorate and carbamate, was attempted in this paper. SchE levels decreased in the fish exposed to both the pesticides, the depletion being more pronounced with phorate. These results can be due to impairment of nervous system, liver damage as well as myocardial infarction. Similar findings were not only reported in experimental organisms but also found in human beings working in agricultural fields and pesticide manufacturing plants. Hence it is imperative that suitable occupational health and preventive measures need to be undertaken.

Toxicological potential to mice of 14C-arbaryl bound residues in faba and soybeans

Sound faba and soybeans were treated with 14C-carbaryl at a dose of 16 mg insecticide/kg grains and stored under local conditions. After 30 weeks of storage the amount of surface residues was 29%, 27% and the internal residues amounted to 56%, 60% in faba and soybeans, respectively. 14C-Bound residues [non-extractable] after 30 weeks of storage was 5% and 6% in faba and soybeans, respectively. Feeding mice for 3 months with a diet containing 14C-carbaryl bound residues in faba and soybeans revealed that these residues have a slight effect and no significant symptoms of toxicity towards mice were observed. A slight inhibition in both plasma and erythrocyte-cholinesterase activity was clear during the first 2 weeks of the experiment with both seeds. Haematological studies showed only a significant decrease in the white blood cell counts as compared with the control mice. The level of blood serum esterases showed a slight increase in liver and kidney functions as compared with controls. Significant differences were clear in kidney function where blood urea nitrogen was increased by [45%, 58%], and creatinine level was elevated by [20%,28%] after 3 months of feeding with faba and soybeans, respectively

Monitoring of resistance to three insecticides on pepper weevil (Anthonomus eugenii) in populations from baja California Sur, México

Se determinaron los niveles de toxicidad en poblaciones de picudo del chile Anthonomus eugenii a tres insecticidas, carbaril, endosulfan y metomil. Las poblaciones de insectos fueron obtenidas a tres localidades en Baja California Sur, México: Benito Juárez (27º53'N 113º46'W), San José Viejo (23º07'N, 109º43'W) and San Juan de los Planes (23º58'N, 109º56'W). Las CL50 más elevadas corresponden al carbaril (178,4;635,4 y 5462,1 µgr/ml); endosulfan, tuvo valores intermedios (36,5; 34,1 y 47,1 µg/ml); mientras que los valores intermedios (36,5; 34,1 y 47,1 µg/ml); mientras que los valores más bajos correspondieron a metomil (1,3; 1,7 y 2,7 µg/ml), para Benito Juárez, San José Viejo y San Juan de los Planes respectivamente. Se puede concluir que las poblaciones de picudo del chile de San Juan de los Planes son resistentes a los tres insecticidas utilizados, teniendo mayor resistencia a carbaril, en comparación con las poblaciones provenientes de San José el Viejo y Benito Juárez. Los niveles susceptibilidad corresponden con las cantidades de insecticidas usados en contra del picudo del chile en las tres localidades de estudio y son una respuesta a la presión selectiva ejercida por esos compuestos

Carbaryl-induced alterations in biochemical metabolism of the prawn, Macrobrachium malcolmsonii.

The present study was performed to investigate the toxic impact of carbaryl on biochemical metabolism in the hemolymph, brain, hepatopancreas, gills and muscle of intermoult juveniles of the economically important prawn, Macrobrachium malcolmsonii. The concentration of glutathione S-transferase (GST) was found to be higher in test prawns when compared with controls. This suggests that a mechanism of detoxification was in operation to neutralise carbaryl toxicity. However, the toxic effect of carbaryl was not fully neutralised, and hence, alterations were recorded in basic biochemical metabolism of test prawns. The concentration of acetylcholinestrase (AchE) was found to be lower in test prawns than that of controls. Carbaryl toxicity resulted in utilisation of major biochemical constituents, such as total carbohydrate, glycogen, protein and lipid to generate required energy as an attempt to withstand the toxic stress. Glycogenolysis resulted in elevation of total free sugar level in the hemolymph of test prawns. While proteolysis led to elevation of total free amino acid level in test prawns. The content of total lipid have also been found lower in test prawns than that of controls. This suggests that carbaryl toxicity resulted in severe energy crises in test prawns. In the present study, toxic effects of carbaryl impair basic metabolic functions and hence pose a threat to the life of M. malcolmsonii.

Skin diseases and enzymatic antioxidant activity among workers exposed to pesticides

In this study, 150 workers exposed to pesticides and 50 healthy control subjects were given clinical and dermatological examinations, patch tests, tests of liver and renal function, complete blood count, blood sugar and urinalysis. Activity of the antioxidant enzymes superoxide dismutase, glutathione peroxidase and glutathione reductase was also evaluated. Dermatological findings were positive in 78%, 76% and 54% of workers exposed to organophosphates, pyrethroids and carbamate pesticides respectively. The patch test was positive in 70% of workers exposed to pyrethroids and 64% exposed to carbamate pesticides. Liver enzyme levels were generally increased in workers while antioxidant enzyme activity was significantly decreased in all workers compared with the controls

Effect of pesticides carbaryl and phorate on serum cholesterol level in fish, Clarias batrachus (Linn).

Freshwater edible catfish Clarias batrachus (Linn.) was treated with sublethal concentration of two different groups of pesticides- carbaryl, a carbamate and phorate, an organophosphate for 24 ,72 ,120 and 168 h. The disorders of lipid metabolism were observed in serum. Cholesterol levels in the serum decreased significantly throughout the exposure period with both the pesticides. These results indicate one significant manifestation of the toxic response from the fish under the stress of pesticide exposure.

Pesticide induced alterations of non-protein nitrogenous constituents in the serum of a fresh water cat fish, Clarias batrachus (Linn.).

A freshwater cat fish was exposed to sublethal concentrations of two pesticides--carbaryl, a carbamate and phorate, an organophosphorus pesticide for 24, 72, 120 and 168 hr. The alterations in the serum profile of non protein nitrogen compounds demonstrated an increase in urea, uric acid and creatinine throughout the experimental period.

Effect of carbaryl and dichlorvos on reproductive system of male albino rats

The current study was designed to assess the toxic responses of dichlorvos and carbaryl on male reproductive system of growing rats Daily doses of 1/100 LD[50] of either insecticides were given by gavage to immature rats for 10 and 15 weeks. Our results revealed that both insecticides have adverse effects on the reproductive system of male rats through: decreased weights of testis, epididymis and accessory sex organs, impairment of sperm cell characters [declined epididymal sperm count, percent of live cells and sperm motility and increased dead and abnormal sperms], the degenerative changes of testicular tissue and alteration of the physiological hormonal balance. Dichlorvos treated rats showed significant decrease in serum concentration of testosterone, FSH and LH, while the effect of carbaryl exposure was restricted to testosterone level alteration. Histological examination of the liver, kidney and testis of the treated rats revealed degenerative changes of hepatocytes, glomerular atrophy, and destruction of seminiferous tubules, respectively. All results were directly proportionate with the period of exposure

Development of cellular slime mould, Dictyostelium discoideum treated with a carbamate pesticide.

Dictyostelium cells when treated with 100 ppm carbaryl or placed on 20 ppm carbaryl agar showed profound changes in the developmental stages. The treated cells showed larger aggregate formations, inhibition of cAMP-chemotaxis and cAMP dependent extracellular phosphodiesterase activity. The fruiting body formations were also scarce. The developing Dictyostelium cells when placed on carbaryl agar showed aberrant morphogenesis with larger aggregates, abnormal slugs and large fruiting bodies. In all cases the development of the treated cells showed considerable delay when compared with controls.