Effect of aldicarb on the growth, respiration and (14C) - glucose metabolism of Axotobacter chroococcum BEIJ.

Aldicarb [2-methyl-2(methyl thio) propionaldehyde-O-methyl carbamoyl oxime], which forms the active ingredient of a systemic oximic carbamate insecticide, at 2 ppm level did not affect the in vitro growth and respiration of Azotobacter chroococcum Beij, while concentrations at 5 ppm and 10 ppm levels were inhibitory. The insecticide treatment at 10 ppm level suppressed the assimilation of (14C) - glucose in the whole cells and in the cellular constitutents viz., cold - TCA soluble, hot TCA soluble fractions and insoluble residue. However, the 14C - incorporation in the alcohol soluble and alcohol-ether soluble fractions was enhanced indicating that aldicarb considerably altered the glucose metabolism of the organism.     

Bendiocarb effect on liver and central nervous system in the chick embryo

The aim of the study was to investigate toxicity of bendiocarb (2, 3-isopropyledene-dioxyphenyl methylcarbamate) to organs of chicken embryo. The toxic action of bendiocarb was observed on liver and central nervous system (CNS). Bendiocarb was administered to chicken embryos at embryonic day (ED) 3 in a dose 500 μ g/egg and 10 ED (800 μ g/egg). The observations showed no macroscopic or microscopic changes in the liver and CNS with either dose or day of incubation when the bendiocarb was administered. The liver and CNS were also investigated for caspase activity in relation to application of bendiocarb and no differences in the number of cells with caspase immunopositivity were observed in comparison with the control. The results obtained indicate that bendiocarb administered in the respective doses showed no toxicity to investigated organs. Furthermore, both at the early (3 ED) and the later (10 ED) stages of development no increase in numbers of apoptotic cells in chicken embryos was observed.     

Micronucleus distribution in human peripheral blood lymphocytes treated in vitro with cadmium chloride in G0 and S phase of the cell cycle

Cadmium chloride (CdCl2 x H2O) in concentrations 10(-3) - 10(-6) M was tested for genotoxicity in human lymphocytes in vitro. The DNA damage was expressed through the occurrence of micronuclei (MN) and was detected using the cytochalasin-B-blocked MN assay. Human blood was treated in the G0 and S phase of the cell cycle. All except the highest concentration of cadmium chloride of 10(-3) M applied in the G0 phase of the cell cycle resulted in the increase in MN cells, but it was not statistically significant. Cadmium chloride added to the cultures in the concentration of 10(-3) M affected the cell growth regardless of the phase. Cadmium chloride added to cultures 24 h after their initiation (early S phase) was found to significantly increase the MN frequency in 10(-4) - 10(-6) M concentrations (P > 0.05).     

Ultrastructural changes in the rabbit liver induced by carbamate insecticide bendiocarb

Carbamates (CB) are used as insecticides and some of them have been registered as human drugs. The mechanism of CB poisoning involves reversible inhibition of acetylcholine esterase. In the present study, we investigated changes in liver ultrastructure in rabbits (Oryctolagus cuniculus) which were administered bendiocarb for 3, 10, 20, and 30 days. Rabbits in all experimental groups received capsules of bendiocarb (96% Bendiocarb, Bayer, Germany) per os daily at a dose of 5 mg/kg of body weight, and after day 11 received the same dose every 48 h. The observed changes were only moderate, focal, and the effect on the liver was not uniform. On the third day of the experiment, injured hepatocytes had dilated bile capillaries with reduced microvilli. There were no visible alterations in the intercellular contacts. Nuclei of these cells were irregular in shape. Many hepatocytes showed considerable increase in the number of peroxisomes. On day 10 of the experiment, the number of peroxisomes was reduced. Other changes, such as dilated rough endoplasmic reticulum and proliferation of smooth endoplasmic reticulum were observed on day 20. The number of lipid droplets in hepatocytes gradually increased. Usually they were present in low numbers, but on day 30 of the experiment their number increased significantly. They coalesced and formed a single lipid droplet which changed the shape of the nuclei. The results presented in this study indicate that both short and long-term administration of bendiocarb affects the liver ultrastructure. At the same time we also observed rapid onset of regeneration of the damaged tissue through activation of hepatocytes and oval cells.     

Biochemical alterations in euryhaline fish, Oreochromis mossambicus exposed to sub-lethal concentrations of an organophosphorus insecticide, monocrotophos

The euryhaline fish, Oreochromis mossambicus was exposed to sub-lethal concentration (1.15 mg l(-1)) of a organophosphorus insecticide, monocrotophos (MCP) for 30 days and allowed to recover for seven days. Alanine aminotransferase (ALAT), aspartate aminotransferase (AAT), acid phosphatase (AcP), alkaline phosphatase (ALP), glycogen, lactate dehydrogenase (LDH), Reduced glutathione (GSH), gluthathione-S-transferase (GST) and acetylcholinesterase (AChE), were assayed in plasma and different tissues at regular intervals of day -3, -7, -15, -30 and after recovery period of seven days. The ALAT and AAT activities were increased in plasma and kidney, where as liver and gill showed decrease. Increase in AcP and ALP activities were observed in plasma, gill and kidney, and reduction of 42% and 50% was observed in liver. Glycogen was depleted in plasma, liver and gill indicates of typical stress related response of the fish with pesticide. LDH activity was decreased in liver and muscle, indicating tissue damage and muscular harm, but a significant increase in LDH activity in gill and brain was observed. Depletion in GSH activity was observed in all the tissues, there by enhancing the lipid peroxidation resulting in cell damage. The induction in hepatic GST levels indicates the protection against the toxicity of xenobiotic-induced lipid peroxidation. There was a significant recovery in all the above biochemical parameters studied in plasma and different tissues, after seven days recovery period. These results revealed that MCP affects the intermediary metabolism of O. mossambicus and that the assayed enzymes can work as good biomarkers of organophosphorus contamination.     

Comparison of effects of paraquat and methidation on enzyme activity and tissue necrosis of carp, following exposure to the pesticides singly or in combination

Under aquarium conditions, treatment with the herbicide paraquat (PQ) and with the insecticide methidation (MD) caused cell damage and stress in carp (Cyprinus carpio L.), as shown by increases in glutamate-dehydrogenase (GIDH, EC 1.4.1.2), glutamate-oxalacetate transaminase (GOT, EC 2.6.1.1) and lactate dehydrogenase (LDH, EC 1.1.1.27) activities and in blood sugar levels. PQ proved synergistic with MD in certain cases as regards the harmful effect exerted. On combined treatment, dilated extracellular spaces were visible by light microscope in the liver, while electronmicroscopic studies revealed signs indicative of cell autolysis in the same organ.     

Immunotoxicity in ascidians: Antifouling compounds alternative to organotins – II. The case of Diuron and TCMS pyridine

Using short-term hemocyte cultures of the colonial ascidian Botryllus schlosseri exposed to various sublethal concentrations of Diuron (3-(3,4-diclorophenyl)-1,1-dimethylurea) and TCMS pyridine (2,3,5,6-tetrachloro-4-(metylsulphonyl)pyridine), we evaluated their immunotoxic effects through a series of cytochemical assays previously used for organotin compounds. At concentrations higher than 250 μ M and 10 μ M for Diuron and TCMS pyridine, respectively, both biocides exerted immunosuppressant effects on Botryllus hemocytes, causing i) deep changes in the cytoskeleton that irreversibly affect cell morphology and phagocytosis, ii) induction of DNA damage, iii) leakage of oxidative and hydrolytic enzymes due to membrane alteration. Unlike organotin compounds, Diuron and TCMS pyridine do not inhibit cytochrome-c-oxidase, and only TCMS pyridine triggers oxidative stress. When co-present, they exert an antagonistic interaction on cytoskeletal components.     

Study on the cytotoxicity of microcystin-LR on cultured cells

The toxicity of purified blue-green algal toxin, microcystin-LR, on permanent cell lines KB, NIH/3T3, H-4-II-E, HeLa, Vero, Hep G2, Caco-2 and HL-60 was studied. Assessment of cell viability using colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays indicated that purified microcystin-LR induced toxic effect on KB and H-4-II-E cell lines after 96 h incubation at toxin concentrations greater than 18.75 microg/ml. KB cell line was selected for further study when reproducibility, consistency and sensitivity were considered. Significant amounts of lactate dehydrogenase (LDH) were released from KB cells when incubation durations were 72 and 96 h with toxin concentrations of 18.75 microg/ml and higher. Although previous studies suggested that microcystin-LR had no cytotoxic effect on permanent cell lines, LDH release assay performed on KB cells indicated that exposure to microcystin-LR could result in damage to the cell membrane.     

Immunotoxicity in ascidians: antifouling compounds alternative to organotins - II. The case of Diuron and TCMS pyridine

Using short-term hemocyte cultures of the colonial ascidian Botryllus schlosseri exposed to various sublethal concentrations of Diuron (3-(3,4-diclorophenyl)-1,1-dimethylurea) and TCMS pyridine (2,3,5,6-tetrachloro-4-(metylsulphonyl)pyridine), we evaluated their immunotoxic effects through a series of cytochemical assays previously used for organotin compounds. At concentrations higher than 250 micro M and 10 micro M for Diuron and TCMS pyridine, respectively, both biocides exerted immunosuppressant effects on Botryllus hemocytes, causing i) deep changes in the cytoskeleton that irreversibly affect cell morphology and phagocytosis, ii) induction of DNA damage, iii) leakage of oxidative and hydrolytic enzymes due to membrane alteration. Unlike organotin compounds, Diuron and TCMS pyridine do not inhibit cytochrome-c-oxidase, and only TCMS pyridine triggers oxidative stress. When co-present, they exert an antagonistic interaction on cytoskeletal components.     

Oxidative stress and biochemical perturbations induced by insecticides mixture in rat testes

The joint action of pyrethroids, lambda-cyhalothrin (LC) in combination with organophosphates, fenitrothione (FNT) on antioxidant defense system and lipid peroxidation biomarkers in rat testes was studied. The results suggest that incubation of testes homogenate with different concentrations of insecticide mixture for different time intervals significantly decreased the activity of antioxidant enzymes, like glutathione S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT), and the level of reduced glutathione (GSH). In addition, a significant inhibition in transaminases (AST, ALT), phosphatases (AcP, AlP) activity and protein content were observed. On the other hand, FNT plus LC increased the cellular lipid peroxidation (LPO) level and the activity of lactate dehydrogenase (LDH). In conclusion, the use of insecticides mixture might cause marked oxidative damage in a concentration and time-dependent manner.     

Cytotoxic response in human lung epithelial cells and ion characteristics of urban-air particles from Torino,a northern Italian city

Recently, much attention has been devoted to urban air pollution because epidemiological studies have reported health impacts related to particulate matter (PM). PM10 and PM2.5 were collected during different seasons in Torino, a northern Italian city, and were characterised by inorganic chemical species (secondary particulates and bio-available iron). The biological effects of aqueous and organic solvent PM extracts on human epithelial lung A549 were evaluated, and the effects on cell proliferation and lactate dehydrogenase (LDH) release were assayed. The average PM10 concentration during the sampling period was 47.9?±?18.0 μg/m³; the secondary particles accounted for 49 %?±?9 % of the PM10 total mass, and the bio-available iron concentration was 0.067?±?0.045 μg/m³. The PM2.5/PM10 ratio in Torino ranged from 0.47 to 0.90 and was higher in cold months than in warm months. The PM10 and PM2.5 extracts inhibited cell proliferation and induced LDH release in a dose-dependent manner with a seasonal trend. The PM10 extract had a stronger effect on LDH release, whereas the PM2.5 extract more strongly inhibited cell proliferation. No significant differences were observed in the effects induced by the two extracts, and no significant correlations were found between the biological effects and the PM components evaluated in this study, thus emphasising the importance of the entire mixture in inducing a cytotoxic response.     

Biodegradation of methoxychlor and its metabolites by the white rot fungus Stereum hirsutum related to the inactivation of estrogenic activity

The white rot fungus Stereum hirsutum was used to degrade methoxychlor [2,2,2-trichloro-1,1-bis(4-methoxyphenyl)ethane] in culture and the degraded products were extensively determined. The estrogenic activity of the degraded products of methoxychlor was examined using cell proliferation and pS2 gene expression assays in MCF-7 cells. S. hirsutum showed high resistance to methoxychlor 100 ppm, and the mycelial growth was fully completed within 8 days of incubation at 30 degrees C. Methoxychlor in liquid culture medium was gradually converted into 2,2-dichloro-1,1-bis(4-methoxyphenyl)ethane, 2,2-dichloro-1,1-bis(4-methoxyphenyl)ethylene, 2-chloro-1,1-bis(4-methoxyphenyl) ethane, 2-chloro-1,1-bis(4-methoxyphenyl) ethylene, and 1,1-bis(4-methoxyphenyl)ethylene, indicating that methoxychlor is dominantly degraded by dechlorination and dehydrogenation. MCF-7 cells were demonstrated to proliferate actively at the 10-5 M concentration of methoxychlor. However, cell proliferation was significantly inhibited by the incubation with methoxychlor culture media containing S. hirsutum. In addition, the expression level of pS2 mRNA was increased at the concentration (10-5 M) of methoxychlor. The reductive effect of S. hirsutum for methoxychlor was clear but not significant as in the proliferation assay.     

Genotoxicity of the organochlorine pesticides 1,1-dichloro-2,2- bis(p-chlorophenyl)ethylene (DDE) and hexachlorobenzene (HCB) in cultured human lymphocytes

The possible genotoxic potential of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), which is a metabolite of dichlorobiphenyltrichloroetane (DDT), and hexachlorobenzene (HCB), which are organochlorine pesticides have been evaluated in vitro by using human lymphocytes as test system. Genetic damage was determined by scoring the frequency of micronuclei (MN) in primary lymphocyte cultures obtained from different donors. The results indicated that, under the experimental conditions used, the DDT metabolite DDE was able to induce significant increases in the frequency of micronucleated cells, which indicate a certain clastogenic and/or aneugenic potential. DDE was tested in the range of 10-80 mM, but the only concentration producing a significant genotoxic effect was 80 mM. On the other hand, HCB was unable to induce a significant increase in the MN frequency in the range of concentrations assayed, from 0.005 to 0.1mM. The selected concentrations of DDE and HCB were chosen according to their toxicity in cell blood cultures; higher concentrations reduced significantly cell proliferation and produced a low frequency of binucleated cells. In conclusion, the results indicate that a genotoxic risk is associated with the exposure to DDE at concentrations 80 mM and above.     

Accelerated degradation of carbofuran in standing water from carbofuran‐retreated Azolla plots

Abstract

Carbofuran (2, 3‐dihydro‐2, 2‐dimethyl‐7‐benzofuranyl N‐methylcarbamate) was mixed with standing water from six flooded Azolla (a fern harboring a nitrogen fixing alga, Anabaena azollae) plots that had been regularly treated with carbofuran before. The insecticide completely disappeared in 5 to 10 days when mixed with water from three of the six plots. The enrichment culture, prepared by further additions of carbofuran to the standing water from an Azolla plot, degraded bendiocarb (2, 2‐dimethyl‐l, 3‐benzidioxol‐4‐yl‐N‐methylcarbamate), carbofuran and carbosulfan [2,3‐dihydro‐2,2‐dimethyl‐7‐benzofuranyl (di‐n‐butyl‐aoinosulfenyl) methyl‐carbamate ] in that order. Enrichment culture, upon sterilization by autoclavlng, lost its ability to degrade carbofuran. Evidently, accelerated degradation of carbofuran in standing water from retreated Azolla plots was mediated by microorganisms.     

Partial compensation of the sublethal effect of deltamethrin on the sex pheromonal communication of Trichogramma brassicae

Pyrethroid insecticides are widely used and lead to a sizable environmental pollution that could interfere with the population biology of insects. Trichogramma is a beneficial insect used in biological control and which natural populations contribute to the control of Lepidopterus pests. In this work, we determined the effect of a sublethal dose of deltamethrin on the sex pheromonal communication of Trichogramma. The dose used (LD 0.1) induces no detectable mortality (the theoretical mortality is only one insect over 1000) and can be a good representation of contamination by this insecticide from environmental pollution. The insecticide was shown to have opposite effects on the sex pheromonal communication of Trichogramma, depending on which sex was exposed (Delpuech, J.M., Legallet, B., Terrier, O., Fouillet, P., 1999. Chemosphere 38, 729–739). We show that, when both sexes are simultaneously exposed to the insecticide, this effect is only partially neutralized. The mean response of treated males responding to the sex pheromone from treated females is not significantly different from that of controls, but the kinetics of their response is not the same. When both sexes are treated, the response of males to the sex pheromone is lower at the beginning but their response does not decrease during time contrary to controls and becomes finally higher than that of controls. Therefore, the sublethal effect of deltamethrin in the field can be either advantageous or disadvantageous depending on the difficulty in finding females and their scarcity.     

Effects of mono-(2-ethylhexyl) phthalate (MEHP) on chicken germ cells cultured in vitro

In recent decades, many toxicological tests based on in vivo or in vitro models, mainly from mammalian (rat–mouse) and fish species, were used to assess the risks raised by contact or ingestion of molecules of pharmaceutical, agricultural, or natural origin. But no, or few, in vitro tests using other non-mammalian models such as bird have been explored despite their advantages: the embryonic gonads of birds have a high plasticity of development sensitive to estrogen, and sperm production is nearly two times faster than in rodents. Hence, we have established an in vitro culture of germ cells and somatic cells from chicken post-natal testis, and we have evaluated the sensitivity against the endocrine disruptor compound mono-(2-ethylhexyl) phthalate (MEHP) in comparison to previous studies using rodent and human models. After 96 h of exposure in presence of 10 μM MEHP, chicken seminiferous tubules cultures present a structural alteration, a reduction in cell proliferation and in germ cells population. Apoptosis of germ and somatic cells increases in presence of 1 μM MEHP. Furthermore, MEHP does not affect inhibin B and lactate production by Sertoli cells. These results are in accordance with previous studies using rat, mice, or human culture of testicular cells and in similar range of exposures or even better sensitivity for some “end-points” (biological parameters). In conclusion, the establishment of this postnatal testicular cells culture could be considered as an alternative method to in vivo experiments frequently used for evaluating the impact on the terrestrial wildlife species. This method could be also complementary to mammal model due to the limiting number of animals used and its elevated sensitivity.     

In vitro effects of acephate on carbonic anhydrase activity in the blood and gills of rainbow trout, Salmo gairdneri

Acephate, a water-soluble organophosphate pesticide used to control terrestrial insect pests, may enter aquatic ecosystems in the course of its use and adversely affect fish populations. The in vitro effects of this insecticide on gill and red blood cell (RBC) carbonic anyhdrase (CA) activity in rainbow trout were investigated over a range of 100 mg/1 (0.55 mM) to 50,000 mg/l (273 mM) to assess the manner in which acephate might affect respiratory capacity in exposed fish. Concentrations required to produce 50% inhibition of CA activity in the gill and RBC preparations were 38,000 mg/l (207 mM) and 8,900 mg/l (48 mM) respectively. The toxic action of acephate may be related to inhibition of CA activity in the blood and gills with resultant disturbances of respiratory capacity and salt balance.     

Biodegradation of Methoxychlor and Its Metabolites by the White Rot Fungus Stereum hirsutum Related to the Inactivation of Estrogenic Activity

The white rot fungus Stereum hirsutum was used to degrade methoxychlor [2,2,2-trichloro-1,1-bis(4-methoxyphenyl)ethane] in culture and the degraded products were extensively determined. The estrogenic activity of the degraded products of methoxychlor was examined using cell proliferation and pS2 gene expression assays in MCF-7 cells. S. hirsutum showed high resistance to methoxychlor 100 ppm, and the mycelial growth was fully completed within 8 days of incubation at 30°C. Methoxychlor in liquid culture medium was gradually converted into 2,2-dichloro-1,1-bis(4-methoxyphenyl)ethane, 2,2-dichloro-1,1-bis(4-methoxyphenyl)ethylene, 2-chloro-1,1-bis(4-methoxyphenyl) ethane, 2-chloro-1,1-bis(4-methoxyphenyl) ethylene, and 1,1-bis(4-methoxyphenyl)ethylene, indicating that methoxychlor is dominantly degraded by dechlorination and dehydrogenation. MCF-7 cells were demonstrated to proliferate actively at the 10^?5 M concentration of methoxychlor. However, cell proliferation was significantly inhibited by the incubation with methoxychlor culture media containing S. hirsutum. In addition, the expression level of pS2 mRNA was increased at the concentration (10^?5 M) of methoxychlor. The reductive effect of S. hirsutum for methoxychlor was clear but not significant as in the proliferation assay.     

Chromosomal aberrations in ovine lymphocytes exposed in vitro to tolylfluanid

Chromosomal aberrations have been used as important cytogenetic biomarkers to study the mutagenic effects of different chemicals in vivo and in vitro. Chromosomal aberrations were evaluated in cultures of sheep lymphocytes in vitro exposed to the fungicide tolylfluanid. Lymphocyte cultures from three donors were exposed to four different concentrations of fungicide (1.10(-4) M(.)L; 1.10(-5) M(.)L; 1.10(-6) M(.)L; 1 × 10(-7) M(.)L). Chromosomal analysis showed a significant (P = 0.018 and 0.038 respectively, Anova test, P < 0.05, Tukey test) increase in the frequency of aberrant cells (ABC) in cultures treated with the highest negative experimental concentrations of tolylfluanid (1.10(-4) M(.)L; 1.10(-5) M(.)L) compared to control. Significantly increased numbers of chromatid breaks (7.67 ± 0.58% against 1.67 ± 2.08%, P = 0.009, Anova test, P < 0.05, Tukey test) and chromatid gaps (7.67 ± 1.15% against 2.67 ± 0.58%, P?= 0.003, Anova test, P < 0.05, Tukey test) were observed in ovine cultures treated with the highest experimental concentration of tolylfluanid (1.10(-4) M(.)L). Tolylfluanid induced also chromosomal exchanges (P = 0.038, and 0.016 respectively, Anova test, P < 0.05, Tukey test) in ovine cultures treated with the highest experimental concentrations of tolylfluanid (1.10(-4) M(.)L; 1.10(-5) M(.)L). The mitotic index has not shown any statistical differences between the various treatments and control groups. Our results suggest a significant genotoxic effect of tolylfluanid only at the highest concentration in sheep peripheral lymphocytes in vitro.     

Use of artificial sediments in a comparative toxicity study with larvae and postlarvae of the grass shrimp, Palaemonetes pugio

An artificial sediment was tested for use in evaluating the potential hazard of toxicants on benthic organisms. The seawater-sediment system was assessed by use of the pyrethroid insecticide, fenvalerate, as the model toxicant for testing with larvae of the grass shrimp, Palaemonetes pugio, an ecologically important estuarine species. The sediment was prepared from commercially available components, and mixed with the toxicant to provide concentrations of 1, 10 and 100 microg fenvalerate kg(-1) dry sediment in 20 ppt seawater. Sediment free of the insecticide served as the control. Throughout the study, fenvalerate was not detected in the water column, but was measured in sediment at the nominal concentration of 100 microg kg(-1). The P. pugio population was adversely affected by fenvalerate. The effect occurred at metamorphosis, when larvae changed from pelagic individuals to benthic organisms. At this period, larvae were in direct contact with sediment. A portion of the population was tolerant of the insecticide.