Clinical effects and cholinesterase activity changes in workers exposed to phorate (Thimet)

Abstract

Phorate (Thimet), an aliphatic derivative of phospnorus is a hignly toxic insecticide. In order to implement the safety measures, the clinical manifestations and cholinesterase (ChE) activity were evaluated before and after 2 weeks of exposure to this insecticide in 40 male tormulators.

The 2 week's exposure reveal signs and symptoms of toxicity in 60% of the formulators. Gastrointestinal symptoms and lowering of heart rate (bradycardia) were more prominent as compared to the neurological symptoms. A significant depression in plasma ChE activity was observed at the end of 1st week (55%) and 2nd week (71%) as compared to the respective pre‐exposure values. A recovery up to 79% of the pre‐exposure activity of this enzyme was noticed 10 days after cessation of the above exposure.     

Assessment of environmental injustice in Korea using synthetic air quality index and multiple indicators of socioeconomic status: A cross-sectional study

Despite the existence of the universal right to a healthy environment, the right is being violated in some populations. The objective of the current study is to verify environmental discrimination associated with socioeconomic status in Korea, using synthetic air quality index and multiple indicators of socioeconomic status. The concentrations of NO₂ (nitrogen dioxide), CO (carbon monoxide), SO₂ (sulfur dioxide), PM₁₀ (particulate matter with an aerodynamic diameter <10 μm), and O₃ (ozone) in ambient air were integrated into a synthetic air quality index. Socioeconomic status was measured at individual level (income, education, number of household members, occupation, and National Basic Livelihood status) and area level (neighborhood index). The neighborhood index was calculated in the finest administrative unit (municipality) by performing standardization and integration of municipality-level data of the following: number of families receiving National Basic Livelihood, proportion of people engaged in an elementary occupation, population density, and number of service industries. Each study participant was assigned a neighborhood index value of the municipality in which they reside. Six regression models were generated to analyze the relationship between socioeconomic status and overall air pollution. All models were adjusted with sex, age, and smoking status. Stratification was conducted by residency (urban/rural). Moran’s I was calculated to identify spatial clusters, and adjusted regression analysis was conducted to account for spatial autocorrelation. Results showed that people with higher neighborhood index, people living with smaller number of family members, and people with no education lived in municipalities with better overall air quality. The association differed by residency in some cases, and consideration of spatial autocorrelation altered the association. This study gives strength to the idea that environmental discrimination exists in some socioeconomic groups in Korea, and that residency and spatial autocorrelation must be considered in order to fully understand environmental disparities.Implications: This is the first study that provides the possible evidence of the environmental injustice in Korea using air quality index. The findings suggested that air quality index was negatively correlated with several important socioeconomic status measured at either individual or area level. The main implication of this paper, therefore, is to provide another insight to environmental policy makers to consider environmental injustice problem into community intervention for resolving the public health problems by air pollution.     

Sorption–desorption of imidacloprid onto a lacustrine Egyptian soil and its clay and humic acid fractions

Sorption–desorption of the insecticide imidacloprid 1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine onto a lacustrine sandy clay loam Egyptian soil and its clay and humic acid (HA) fractions was investigated in 24-h batch equilibrium experiments. Imidacloprid (IMDA) sorption–desorption isotherms onto the three sorbents were found to belong to a non-linear L-type and were best described by the Freundlich model. The value of the IMDA adsorption distribution coefficient, Kd_ads, varied according to its initial concentration and was ranged 40–84 for HA, 14–58 for clay and 1.85–4.15 for bulk soil. Freundlich sorption coefficient, Kf_ads, values were 63.0, 39.7 and 4.0 for HA, clay and bulk soil, respectively. The normalized soil Koc value for imidacloprid sorption was ～800 indicating its slight mobility in soils. Nonlinear sorption isotherms were indicated by 1/n_ads values <1 for all sorbents. Values of the hysteresis index (H) were <1, indicating the irreversibility of imidacloprid sorption process with all tested sorbents. Gibbs free energy (ΔG) values indicated a spontaneous and physicosorption process for IMDA and a more favorable sorption to HA than clay and soil. In conclusion, although the humic acid fraction showed the highest capacity and affinity for imidacloprid sorption, the clay fraction contributed to approximately 95% of soil-sorbed insecticide. Clay and humic acid fractions were found to be the major two factors controlling IMDA sorption in soils. The slight mobility of IMDA in soils and the hysteresis phenomenon associated with the irreversibility of its sorption onto, mainly, clay and organic matter of soils make its leachability unlikely to occur.     

Liver alterations in Oreochromis niloticus (Pisces) induced by insecticide imidacloprid: Histopathology and heat shock protein in situ localization

Liver is very sensitive to environmental contaminants such as pesticides, it being the first target of toxicity of a substance. The objective of this study was to investigate the possible effects of the insecticide imidacloprid (IMI) on the liver of Oreochromis niloticus according concentrations used for growing sugarcane. A semi-quantitative analysis of histopathological alterations of IMI on liver was performed by light microscopy and cellular labeling of heat shock proteins (HSP70) by immunohistochemistry. The most common changes in liver at all concentrations of IMI were hydropic degeneration, pyknotic nuclei, and loss of cell limits. Steatosis and increased levels of HSP70 were detected in hepatocytes with the highest concentration of IMI. In conclusion, the tested concentrations of IMI induced histopathological changes in the liver of O. niloticus and active defence mechanisms to maintain the morphophysiological integrity of the liver. This insecticide has a toxicity potential for these fish, which is a non-target organism of its action.     

Endosulfan and Quinalphos Residues and Toxicity to Soil Microarthropods after Repeated Applications in a Field Investigation

Endosulfan (1,4,5,6,7,7-hexachloro-8,9,10-trinorborn-5-en-2,3-ylenedimethylsulphite) and quinalphos (O,O-diethyl O-quinoxalin-2-yl phosphorothioate) persistence and their effect on soil microarthropods were studied after repeated applications in cotton fields. Dissipation behavior of insecticides after repeated applications was observed from 78 to 292 days after the first insecticide treatment. At any given time the concentrations of endosulfan β residues were always higher as compared to endosulfan α. From 78 to 85 days, 5.0% and 20.4% decrease in α and β endosulfan residues was observed, respectively. Endosulfan β isomer decreased up to 93.0% in 292 days. Endosulfan sulfate was detected as a major metabolite in the soil samples. Total endosulfan residues decreased by 86.6% from 78 to 292 days. The amounts of quinalphos residues were less as compared to endosulfan at any given time. The residues observed after 78 days of application were 0.88 ng g^?1 d wt. soil. At the end of 145 days, a 35.0% decrease in quinalphos residue was observed, which decreased further by 50.9% in 292 days. Among the soil microarthropods studied, Acarina was more sensitive to the applied insecticides as compared to Collembola. Three days after the last treatment, up to 94.5% (p < 0.01) and 71.2% (p < 0.05) decrease in Acarina population was observed in endosulfan and quinalphos treated fields, respectively, compared to control field. In general, no noticeable change in Collembola population was observed after the insecticide treatments.     

Do herbicide treatments reduce the sensitivity of mosquito larvae to insecticides?

Invasive mosquitoes are economic and sanitary concerns especially in Europe and America. Most work has emphasized the role of resistance [Berrada, S., Fournier, D., Cuany, A., Nguyen, T.X., 1994. Identification of resistance mechanisms in a selected laboratory strain of Cacopsylla pyri (Homoptera: Psyllidae): altered acetylcholinesterases and detoxifying oxidases. Pesticide Biochemistry and Physiology 48, 41-47; Hemingway, J., Hawkes, N.J., McCarroll, L., Ranson, H., 2004. The molecular basis of insecticide resistance in mosquitoes. Insect Biochemistry and Molecular Biology 34, 653-665] to insecticides. Compounds acting on larval sensitivity to insecticides are not well studied and their action remains poorly understood. Among several residual chemicals in ecosystems, particularly in wetlands, we identified a possible interaction of an herbicide on larval resistance to an insecticide. Our work contributes to the global control of mosquito populations by identifying possible pathways of resistance to insecticides of these vectors. Resistance or tolerance to insecticide treatments might contribute to successful invasion by mosquitoes. Here we report an ecotoxicological approach to test the hypothesis of an indirect effect of atrazine on mortality of an invasive vector. A brief contact (48h) between Aedes aegypti mosquito larvae and atrazine led to a modification of larval sensitivity to an insecticide: using atrazine as an inducer led to a decrease in the mortality of larvae treated with Bacillus thuringiensis var. israelensis (Bti).     

Biodegradation of imidacloprid in liquid media by an isolated wastewater fungus Aspergillus terreus YESM3

In the present study, a new fungal strain capable of imidacloprid degradation was isolated from agricultural wastewater drain. The fungal strain of YESM3 was identified as Aspergillus terreus based on ITS1-5.8S rDNA-ITS2 gene sequence by PCR amplification of a 500 bp sequence. Screening of A. terreus YESM3 to the insecticide imidacloprid tolerance was achieved by growing fungus in Czapek Dox agar for 6 days at 28°C. High values (1.13 and 0.94 cm cm^?1) of tolerance index (TI) were recorded at 25 and 50 mg L^?1 of imidacloprid, respectively in the presence and absence of sucrose. However, at 400 mg L^?1 the fungus did not grow. Effects of the imidacloprid concentration, pH, and inoculum size on the biodegradation percentage were tested using Box–Behnken statistical design and the biodegradation was monitored by HPLC analysis at different time intervals. Box–Behnken results indicated that optimal conditions for biodegradation were at pH 4 and two fungal discs (10 mm diameter) in the presence of 61.2 mg L^?1 of imidacloprid. A. terreus YESM3 strain was capable of degrading 85% of imidacloprid 25 mg L^?1 in Czapek Dox broth medium at pH 4 and 28°C for 6 days under static conditions. In addition, after 20 days of inoculation, biodegradation recorded 96.23% of 25 mg L^?1 imidacloprid. Degradation kinetics showed that the imidacloprid followed the first order kinetics with half-life (t₅₀) of 1.532 day. Intermediate product identified as 6-chloronicotinic acid (6CNA) as one of the major metabolites during degradation of imidacloprid by using HPLC. Thus, A. terreus YESM3 showed a potential to reduce pollution by pesticides and toxicity in the effected environment. However, further studies should be conducted to understand the biodegradation mechanism of this pesticide in liquid media.     

Aliphatic Hydrocarbons Distribution in Sediment Cores of Select Creeks in Delta State,Nigeria

The spatial and seasonal changes in the distribution, composition, and concentrations of aliphatic hydrocarbons were investigated in sediment cores of Ubeji, Ifie, and Egbokodo Creeks in the Niger Delta, Nigeria. A total of 222 sediment core samples were collected during the wet season (August 2010) and the dry season (January 2011). The samples were dried, soxhlet extracted, fractionated and analyzed for aliphatic hydrocarbons by using a gas chromatograph with flame ionization detector (GC-FID). The concentrations of aliphatic hydrocarbons ranged from 37 to 286,894 μg/kg (wet season) and from 30 to 11,773 μg/kg (dry season). The concentrations of n-alkanes for a number of stations in this study are comparable to sites with high anthropogenic activities in the Niger Delta. The carbon preference index (CPI) and the pristane/phytane ratios showed that the major source of hydrocarbon pollution in the sediment core was from petrogenic origin.     

Methidathion Complexes with Homoionic and Surfactant-Modified Montmorillonites

Abstract

The formation of the insecticide methidathion (S-[(5-methoxy-2-oxo-1,3,4-thiadiazol-3(2H)-yl)methyl] O,O-dimethyl phosphorodithioate) complexes with inorganic cation-saturated (Mg²⁺, Ca²⁺, Cu²⁺, and Ni²⁺) montmorillonites was investigated. The nature and structure of the complexes was determined by X-ray diffraction and infrared spectroscopy. The arrangement of the pesticide molecule in the interlayer space was also considered from ab initio calculations using simpler related molecules. The insecticide methidathion penetrated the interlayer spaces of the homoionic clay samples. The ligand–cation interactions in these complexes depend on the nature and characteristics of the saturating cations. Mechanisms involving water bridges and direct coordination with the exchange cation were proposed for the adsorption of methidathion by inorganic cation-saturated montmorillonites. The effect of the inorganic cations on the sorption of the cationic surfactant tetradecyltrimethylammonium bromide (TDTMA) by montmorillonite was also studied and the subsequent sorption of methidathion in TDTMA⁺-Montmorillonite determined. Van der Waals bonds constitute the methidathion adsorption mechanism by montmorillonite saturated with TDTMA⁺. The arrangements of methidathion and of the cationic surfactant molecules in the montmorillonite interlayer space were demostrated.     

Titanium dioxide nanoparticles relieve biochemical dysfunctions of fifth-instar larvae of silkworms following exposure to phoxim insecticide

Phoxim insecticide is widely used in agriculture, which is toxic to insect pests and nontarget organisms. The phoxim poisoning is hard to prevent for silkworms. TiO₂ NPs have been widely applied in whitening, brightening foods, toothpaste or sunscreens, and orally-administered drugs. However, whether TiO₂ NPs can increase resistance of silkworm to phoxim poisoning has not been reported. The results demonstrated that added TiO₂ NPs significantly decreased reduction of protein, glucose and pyruvate contents, lactate dehydrogenase, succinate dehydrogenase and malate dehydrogenase activities, and attenuated increases of free amino acids, urea, uric acid and lactate levels, activities of protease, alanine aminotransferase and aspartate aminotransferase in the hemolymph of silkworms caused by phoxim exposure. From the present study, it is clearly evident that added TiO₂ NPs may relieve toxic impacts of phoxim insecticide on silkworm metabolism, which in turn may result in an increase in silk yield.     

Polychlorinated biphenyls and organochlorine pesticides in Baltic Sea sediments and bivalves

Insecticide resistance is an evolutionary response to insecticides and, as such, important for environmental biomonitoring and for pest management. Fitness disadvantage in the absence of insecticide is a frequent assumption in models of insecticide resistance evolution, which was observed in different insect species. Fitness studies are based in demographic performance of isolated populations without direct interaction between insecticide-resistant and -susceptible populations. Here we reported a study of direct competition following a factorial bivariate design between an insecticide-susceptible population of the maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), and one of two insecticide-resistant populations - one exhibiting fitness disadvantage based on demographic studies (Juiz de Fora) and other not exhibiting it (Jacarezinho). Total number of insects, mortality by insecticide, insect body mass and respiration rate were recorded after three generations of competition. Indeed, fitness disadvantage was observed in the resistant population from Juiz de Fora, but not in the population from Jacarezinho, as expected. The higher body mass and respiration rate of the insecticide-resistant insects from Jacarezinho are probably mitigating the physiological costs associated with the insecticide resistance minimizing their fitness disadvantage, what does not take place with the insecticide-resistant insects from Juiz de Fora. These distinct responses between the insecticide-resistant populations are probably related to the length and intensity of field-selection with insecticides.     

Environment polluting conventional chemical control compared to an environmentally friendly IPM approach for control of diamondback moth, <Emphasis Type="Italic">Plutella xylostella</Emphasis> (L.), in China: a review

The diamondback moth, Plutella xylostella, is recognized as a widely distributed destructive insect pest of Brassica worldwide. The management of this pest is a serious issue, and an estimated annual cost of its management has reached approximately US$4 billion. Despite the fact that chemicals are a serious threat to the environment, lots of chemicals are applied for controlling various insect pests especially P. xylostella. An overreliance on chemical control has not only led to the evolution of resistance to insecticides and to a reduction of natural enemies but also has polluted various components of water, air, and soil ecosystem. In the present scenario, there is a need to implement an environmentally friendly integrated pest management (IPM) approach with new management tactics (microbial control, biological control, cultural control, mating disruption, insecticide rotation strategies, and plant resistance) for an alternative to chemical control. The IPM approach is not only economically beneficial but also reduces the environmental and health risks. The present review synthesizes published information on the insecticide resistance against P. xylostella and emphasizes on adopting an alternative environmentally friendly IPM approach for controlling P. xylostella in China.     

Diversity of antibiotic resistance genes and encoding ribosomal protection proteins gene in livestock waste polluted environment

The rapid development and increase of antibiotic resistance are global phenomena resulting from the extensive use of antibiotics in human clinics and animal feeding operations. Antibiotics can promote the occurrence of antibiotic resistance genes (ARGs), which can be transferred horizontally to humans and animals through water and the food chain. In this study, the presence and abundance of ARGs in livestock waste was monitored by quantitative PCR. A diverse set of bacteria and tetracycline resistance genes encoding ribosomal protection proteins (RPPs) from three livestock farms and a river were analyzed through denaturing gradient gel electrophoresis (DGGE). The abundance of sul(I) was 10³ to 10⁵ orders of magnitude higher than that of sul(II). Among 11 tet-ARGs, the most abundant was tet(O). The results regarding bacterial diversity indicated that the presence of antibiotics might have an evident impact on bacterial diversity at every site, particularly at the investigated swine producer. The effect of livestock waste on the bacterial diversity of soil was stronger than that of water. Furthermore, a sequencing analysis showed that tet(M) exhibited two genotypes, while the other RPPs-encoding genes exhibited at least three genotypes. This study showed that various ARGs and RPPs-encoding genes are particularly widespread among livestock.     

Occurrence of Fipronil in residential house dust in the presence and absence of pets: a hint for a comprehensive toxicological assessment

The presence of the insecticide Fipronil and its main products of toxicological relevance, namely Sulfone and Desulfinyl, was assessed in 161 residential house dust samples in the absence (N?=?101) and presence (N?=?60) of cats and dogs in Italy. High-resolution mass spectrometry analysis revealed a significant difference (p?<?0.001) in the dust contamination in the presence of pets (median: 467 vs. 24?ng/g dry weight), even if the highest value was found in the absence of pets (82,069 vs. 67,799?ng/g dry weight). Fipronil intake estimates from dust in toddlers, computed according to US-EPA and EU-ECHA guidelines, ranged from 333 to 556 and from 20 to 34?ng/kg per day for acute and chronic scenario, respectively. Dust seemed not able itself to lead to Fipronil overexposure with respect to acute and chronic toxicity health-based guidance values. Kittens were potentially overexposed to Fipronil under both acute (26,076?ng/kg per day) and chronic (1,633?ng/kg per day) scenarios. The mild symptomatology associated with acute intoxication could possibly determine case underreporting within pharmacosurveillance schemes. Its administration was estimated in 7.3–9.7 tons per year. Such a range suggests its prudent use under strict veterinary control to prevent pest resistance and ecotoxicological outcomes.     

Effect of Dursban 480 EC (chlorpyrifos) and Talstar 10 EC (bifenthrin) on the physiological and genetic diversity of microorganisms in soil

This investigation was undertaken to determine the impact of the insecticides Dursban 480 EC (with organophosphate compound chlorpyrifos as the active ingredient) and Talstar 10 EC (with pyrethroid bifenthrin as the active ingredient) on the respiration activity and microbial diversity in a sandy loam luvisol soil. The insecticides were applied in two doses: the maximum recommended dose for field application (15 mg kg^?1 for Dursban 480 EC and 6 mg kg^?1 for Talstar 10 EC) and a 100-fold higher dose for extrapolation of their effect. Bacterial and fungal genetic diversity was analysed in soil samples using PCR DGGE and the functional diversity (catabolic potential) was studied using BIOLOG EcoPlates at 1, 3, 7, 14, 28, 56 and 112 days after insecticide application. Five bacterial groups (α, β, γ proteobacteria, firmibacteria and actinomycetes) and five groups of fungi or fungus-like microorganisms (Ascomycota, Basidiomycota, Chytridiomycota, Oomycota and Zygomycota) were analysed using specific primer sets. This approach provides high resolution of the analysis covering majority of microorganisms in the soil. Only the high-dose Dursban 480 EC significantly changed the community of microorganisms. We observed its negative effect on α- and γ-proteobacteria, as the number of OTUs (operational taxonomic units) decreased until the end of incubation. In the β-proteobacteria group, initial increase of OTUs was followed by strong decrease. Diversity in the firmibacteria, actinomycetes and Zygomycota groups was minimally disturbed by the insecticide application. Dursban 480 EC, however, both positively and negatively affected certain species. Among negatively affected species Sphingomonas, Flavobacterium or Penicillium were detected, but Achromobacter, Luteibacter or Aspergillus were supported by applied insecticide. The analysis of BIOLOG plates using AWCD values indicated a significant increase in metabolic potential of microorganisms in the soil after the high-dose Dursban application. Analysis of respiration demonstrated high microbial activity after insecticide treatments; thus, microbial degradation was relatively fast. The half-life of the active insecticide compounds were estimated within the range of 25 to 27 days for Talstar and 6 to 11 days for Dursban and higher doses stimulated degradation. The recommended dose levels of both insecticides can be considered as safe for microbial community in the soil.     

Sorption of polar and nonpolar organic contaminants by oil-contaminated soil

Sorption of nonpolar (phenanthrene and butylate) and polar (atrazine and diuron) organic chemicals to oil-contaminated soil was examined to investigate oil effects on sorption of organic chemicals and to derive oil–water distribution coefficients (K_oil). The resulting oil-contaminated soil–water distribution coefficients (K_d) for phenanthrene demonstrated sorption-enhancing effects at both lower and higher oil concentrations (C_oil) but sorption-reducing (competitive) effects at intermediate C_oil (approximately 1 g kg⁻¹). Rationalization of the different dominant effects was attempted in terms of the relative aliphatic carbon content which determines the accessibility of the aromatic cores to phenanthrene. Little or no competitive effect occurred for butylate because its sorption was dominated by partitioning. For atrazine and diuron, the changes in K_d at C_oil above approximately 1 g kg⁻¹ were negligible, indicating that the presently investigated oil has little or no effect on the two tested compounds even though the polarity of the oil is much less than soil organic matter (SOM). Therefore, specific interactions with the active groups (aromatic and polar domains) are dominantly responsible for the sorption of polar sorbates, and thus their sorption is controlled by available sorption sites. This study showed that the oil has the potential to be a dominant sorptive phase for nonpolar pollutants when compared to SOM, but hardly so for polar compounds. The results may aid in a better understanding of the role of the aliphatic and aromatic domains in sorption of nonpolar and polar organic pollutants.     

Kinetics of carbofuran insecticide conversion under methanogenic conditions

Abstract

This study reports on the kinetics of carbofiiran insecticide transformation under controlled aquatic methanogenic conditions. Attempts were also made to investigate the effects of culture acclimation on the kinetics of carbofiiran transformation.

The results indicate that in an anaerobic system carbofuran was hydrolyzed to carbofiiran phenol and monomethyl amine by hydrolysis. Analysis of the kinetic parameters showed that active anaerobic cultures (both acclimated and unnacclimated) do not enhance the rate of hydrolysis of carbofuran. The hydrolysis product, monomethyl amine, was further mineralized by the methanogenic culture. The major product of carbofuran hydrolysis, carbofiiran phenol, was resistant to further degradation.     

Single-solute and bi-solute sorption of phenanthrene and pyrene onto pine needle cuticular fractions

To better understand interaction mechanisms of pine needles with persistent organic pollutants, single-solute and bi-solute sorption of phenanthrene and pyrene onto isolated cuticular fractions of pine needle were investigated. The structures of cuticular fractions were characterized by elemental analysis, Fourier transform infrared spectroscopy and solid-state ¹³C NMR. Polymeric lipids (cutin and cutan) exhibited notably higher sorption capabilities than the soluble lipids (waxes), while cellulose showed little affinity with sorbates. With the coexistence of the amorphous cellulose, the sorption of cutan (aromatic core) was completely inhibited, so the cutin components (nonpolar aliphatic moieties) dominated the sorption of bulk needle cuticle. By the consumption of the amorphous cellulose under acid hydrolysis, sorption capacities of the de-sugared fractions were dramatically enhanced, which controlled by the exposed aromatic cores and the aliphatic moieties. Furthermore, the de-sugared fractions demonstrated nonlinear and competitive sorption due to the specific interaction between aromatic cores and polycyclic aromatic hydrocarbon.     

Etude sur l'activite initiale et la persistance d'un larvicide experimental a base de bacillus thuringiensis var. israelensis et d'une preparation commerciale contenant l'insecticide organophosphore temephos

Abstract

The larvicide activity of the experimental preparation SAN 402 I WDC containing B. Thuringiensis var. Israelensis and that of Abate 500 E (44 % temephos) were tested on the larvae of Aedes aegypti. The studies were performed on the following media : distilled water, pure and buffered at pH 9, 7 and 4 and pond water whether or not free from materials in suspension. The activity of both preparations is not influenced by the composition of the media, exception made for the presence of materials in suspension. The persistance varies according to the kind of the media and the concentration level. It is in general rather low. Both preparations behave rather similar, the microbial insecticide however is more influenced by the presence of materials in. suspension.     

The effect of thiacloprid formulation on DNA/chromosome damage and changes in GST activity in bovine peripheral lymphocytes

The potential genotoxic effect of thiacloprid formulation on bovine peripheral lymphocytes was evaluated using the comet assay and the cytogenetic endpoints: chromosome aberrations (CAs), sister chromatid exchanges (SCEs) and micronuclei (MNi). Whole blood cultures were treated with the insecticide at concentrations of 30, 60, 120, 240 and 480 μg mL^?1 for 24, 48 h and/or 2 h of incubation. A statistically significant increase in the frequency of DNA damage, as well as in unstable chromosome aberrations (% breaks) were found after exposure to the insecticide at concentrations ranging from 120 to 480 μg mL^?1 (P < 0.05, P < 0.01, P < 0.001). For the detection of stable structural chromosome aberrations (e.g., translocations) and numerical aberrations by the FISH method, three whole chromosome painting probes for bovine chromosomes 1, 5 and 7 (BTA1, BTA5 and BTA7) were used in our experiments. We observed numerical aberrations, but without any statistical significance. Regarding the sister chromatid exchanges, no significant elevation in the SCE frequencies was found after 24-h exposure to the insecticide. A dose-related response in the SCE induction was obtained in bovine cultures after the prolonged time of exposure (48 h) to thiacloprid formulation at concentrations ranging from 120 to 480 μg mL^?1 in each donor (P < 0.05, P < 0.01), which was associated with a reduction of the PI (P < 0.05, P < 0.01). The insecticide failed to produce MNi; however, a significant reduction of CBPI was observed. Using real-time PCR, a decrease in the expression of bovine glutathione S-transferase M3 (GSTM3) was detected at the lowest dose. The higher concentrations of thiacloprid formulation caused an increase in the mRNA expression.