Diastereomeric and enantiomeric selective accumulation of cypermethrin in the freshwater mussel Unio gibbus and its effects on biochemical parameters

Exploring Release, Isomerization, and Absorption of Cypermethrin in Pacific Oysters (Crassostrea gigas) with Different Processing Methods during In Vivo Digestion: Insights from a Gastrointestinal Tract Quantitative Tracing Method

Cypermethrin (CP) is a neurotoxic insecticide found accumulated in oysters, one of the most commonly consumed seafoods, posing potential health risks to the human body. We designed a gastrointestinal tracing method allowing for accurate quantification of the propulsion of chyme and further established the mouse in vivo digestion model to explore the behavior of CP in the digestion of raw, steamed, and roasted oysters. The results showed that bioaccumulation of CP in oysters may be accompanied by the biotransformation of CP. Thermal processing decreased both the CP content in oysters and its bioaccessibility. The small intestine is the main site for CP digestion and absorption. The cis-isomers of CP might finally accumulate in the body at a higher ratio and further become the predominant configuration for toxic effects. Taken together, the study contributes to the risk assessment of the dietary exposure of CP from aquatic products.

Insecticidal efficacy and possibility of Combretum trifoliatum Vent. (Myrtales: Combretaceae) extracts in controlling Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

BACKGROUND

The fall armyworm Spodoptera frugiperda (J.E. Smith), is an important pest of agronomical crops. It is interesting to discover secondary metabolites in plants that are environmentally safer than synthetic pesticides. For this purpose, Combretum trifoliatum crude extract and its isolated compounds were investigated for their insecticidal activities against S. frugiperda.

RESULTS

The median lethal dose (LD50 ) was evaluated in the second-instar larvae using the topical application method. The isolated compounds, apigenin and camphor, demonstrated a highly toxic effect on larvae at a lower LD50 dose than crude extract. Moreover, when the larvae were exposed to crude extract concentrations, the development to pupa and adult stages was reduced by more than 50%. The ovicidal toxicity was examined using a hand sprayer. The extract concentration 5, 10, and 20 μg/egg significantly decreased the egg hatchability. In addition, crude extract showed a significant difference in inhibiting acetylcholinesterase (AChE) activity while crude extract and camphor showed significant inhibitory effects on carboxylesterase (CE) and glutathione-S-transferase (GST) activities.

CONCLUSION

The crude ethanol extract of Combretum trifoliatum was toxic to S. frugiperda in terms of larval mortality, negatively affecting biological parameters, and decreasing egg hatchability. Additionally, the activities of cholinergic and detoxifying enzymes were affected by crude extract and its isolated compounds. These results highlight that Combretum trifoliatum might be efficient as a bioinsecticide to control S. frugiperda. © 2023 Society of Chemical Industry.

Pyrethroids toxicity in vertebrates and invertebrates and amelioration by bioactive compounds: A review

Generations of different synthetic pesticides have been launched over time to maintain balance between production and consumption of the agricultural yield, control various disease programmes, store grains, etc. Pyrethroids, which are supposed to be non-toxic, have been excessively implemented and have contaminated soil and water bodies. Thus, pyrethroids cause severe and dreadful pernicious effects on various life forms residing in soil, air, and water. Various obnoxious effects of pyrethroids have been analyzed in the vertebrate and invertebrate systems of the animal kingdom. Pyrethroids, namely, Cypermethrin, Deltamethrin, Beta-cyfluthrin, Esfenvalerate, Fenvalerate, and Bifenthrin, have set out various types of degenerative and toxic impacts that include oxidative stress, hepatotoxicity, immunotoxicity involving thymic and splenic toxicity, neurotoxicity, nephrotoxicity, foetal toxicity, alterations in serum calcium and phosphate levels, cerebral and bone marrow degeneration, degeneration of the reproductive system, histological alteration, and DNA damage. Bioactive compounds like Diosmin, Curcumin, Rutin, Spirulina platensis, sesame oil, Naringin, Allicin, Piperine, alpha-lipoic acid, alpha-tocopherol, Cyperus rotundus L. tuber extract, herbal syrup from chicory and artichoke leaves, green tea extract, Quercetin, Trans-ferulic acid, Ascorbic acid, Propolis, ethanolic extract of grape pomace, and Melatonin have been reported to sublime the toxic effects of these pesticides. The expanding harmfulness of pesticides is a real and demanding issue that needs to be overcome, and bioactive compounds have been shown to reduce the toxicity in vivo as well as in vitro.

Enantioselective Behaviors of Chiral Pesticides and Enantiomeric Signatures in Foods and the Environment

Unreasonable application of pesticides may result in residues in the environment and foods. Chiral pesticides consist of two or more enantiomers, which may exhibit different behaviors. This Review intends to provide progress on the enantioselective residues of chiral pesticides in foods. Among the main chiral analytical methods, high performance liquid chromatography (HPLC) is the most frequently utilized. Most chiral pesticides are utilized as racemates; however, due to enantioselective dissipation, bioaccumulation, biodegradation, and chiral conversion, enantiospecific residues have been found in the environment and foods. Some chiral pesticides exhibit strong enantioselectivity, highlighting the importance of evaluation on an enantiomeric level. However, the occurrence characteristics of chiral pesticides in foods and specific enzymes or transport proteins involved in enantioselectivity needs to be further investigated. This Review could help the production of some chiral pesticides to single-enantiomer formulations, thereby reducing pesticide consumption as well as increasing food production and finally reducing human health risks.

Simultaneously enhancement in the assimilation of microalgal nitrogen and the accumulation of carbohydrate by Debaryomyces hansenii

Microalgae-based techniques are considered an alternative to traditional activated sludge processes for removing nitrogen from wastewater. Bacteria consortia have been broadly conducted as one of the most important partners. However, fungal effects on the removal of nutrients and changes in physiological properties of microalgae, and their impact mechanisms remain unclear. The current work demonstrates that, adding fungi increased the nitrogen assimilation of microalgae and the generation of carbohydrates compared to pure microalgal cultivation. The NH₄⁺-N removal efficiency was 95.0% within 48 h using the microalgae-fungi system. At 48 h, total sugars (glucose, xylose, and arabinose) accounted for 24.2 ± 4.2% per dry weight in the microalgae-fungi group. Gene ontology (GO) enrichment analysis revealed that, among various processes, phosphorylation and carbohydrate metabolic processes were more prominent. Gene encoding the key enzymes of glycolysis, pyruvate kinase, and phosphofructokinase were significantly up-regulated. Overall, for the first time, this study provides new insights into the art of microalgae-fungi consortia for producing value-added metabolites.

Enhancing the Toxicity of Cypermethrin and Spinosad against Spodoptera littoralis (Lepidoptera: Noctuidae) by Inhibition of Detoxification Enzymes

The extensive use of wide-ranging insecticides in agricultural activities may develop resistance in insects. The dipping technique was utilized for examining changes in detoxifying enzyme levels in Spodoptera littoralis L. induced by cypermethrin (CYP) and spinosad (SPD) with and without a combination of three enzyme inhibitors: triphenyl phosphate (TPP), diethyl maleate (DEM), and piperonyl butoxide (PBO), at 70 μg/mL. PBO, DEM, and TPP showed 50% mortality against larvae at 236.2, 324.5, and 245.8 μg/mL, respectively. The LC₅₀ value of CYP on S. littoralis larvae reduced from 2.86 μg/mL to 1.58, 2.26, and 1.96 μg/mL, while the LC₅₀ value of SPD declined from 3.27 μg/mL to 2.34, 2.56, and 2.53, with the addition of PBO, DEM, and TPP, respectively, 24 h after treatment. Moreover, the activity of carboxylesterase (CarE), glutathione S-transferase (GST), and cytochrome P450 monooxygenase (Cyp 450) was significantly inhibited (p < 0.05) by TPP, DEM, PBO plus CYP, and SPD in S. littoralis larvae in comparison with tested insecticides alone. These findings suggested that three enzyme inhibitors play a major role in increasing the toxicity of CYP and SPD in S. littoralis and will provide insight into how to overcome insecticide resistance in insects.

Ecological risk assessment of pesticides in sediments of Pampean streams, Argentina

After their application in agricultural areas, pesticides are dispersed throughout the environment, causing contamination problems. In Argentina, the main promoter of transgenic biotechnology in the region, the total consumption of agrochemicals has increased significantly in recent years. Most chemicals dumped near surface waters eventually end up in bottom sediments and can be toxic to the organisms that live there. However, published data on the mixing of pesticides in this compartment is still scarce. The objective of this work was to detect and quantify pesticide residues in the sediment of rural streams in the Pampas region and to carry out acute and chronic risk assessment in these aquatic ecosystems. The study area comprises the mountainous system of Tandilia, located in one of the most productive agricultural areas in the country. The concentration of atrazine, acetochlor, chlorpyrifos, cypermethrin, and 2,4-D in the sediment of four rural streams was determined in three different seasons, and the toxic units (TU) and the risk ratios (RQ) were calculated. All the compounds analyzed were detected in most of the sampling seasons and study sites, at concentrations higher than those established in the national and international quality guidelines for the protection of aquatic biota in surface waters and for human consumption. Chlorpyrifos, cypermethrin, and acetochlor were the main pesticides contributing to the TU and RQ values, representing a medium or high ecological risk in most of the sites. Therefore, the evaluation of these pesticides in the bottom sediments could be a decisive factor in assessing the risk to the aquatic environment.

A global synthesis of ecosystem services provided and disrupted by freshwater bivalve molluscs

Identification of ecosystem services, i.e. the contributions that ecosystems make to human well-being, has proven instrumental in galvanising public and political support for safeguarding biodiversity and its benefits to people. Here we synthesise the global evidence on ecosystem services provided and disrupted by freshwater bivalves, a heterogenous group of >1200 species, including some of the most threatened (in Unionida) and invasive (e.g. Dreissena polymorpha) taxa globally. Our systematic literature review resulted in a data set of 904 records from 69 countries relating to 24 classes of provisioning (N = 189), cultural (N = 491) and regulating (N = 224) services following the Common International Classification of Ecosystem Services (CICES). Prominent ecosystem services included (i) the provisioning of food, materials and medicinal products, (ii) knowledge acquisition (e.g. on water quality, past environments and historical societies), ornamental and other cultural contributions, and (iii) the filtration, sequestration, storage and/or transformation of biological and physico-chemical water properties. About 9% of records provided evidence for the disruption rather than provision of ecosystem services. Synergies and trade-offs of ecosystem services were observed. For instance, water filtration by freshwater bivalves can be beneficial for the cultural service 'biomonitoring', while negatively or positively affecting food consumption or human recreation. Our evidence base spanned a total of 91 genera and 191 species, dominated by Unionida (55% of records, 76% of species), Veneroida (21 and 9%, respectively; mainly Corbicula spp.) and Myoida (20 and 4%, respectively; mainly Dreissena spp.). About one third of records, predominantly from Europe and the Americas, related to species that were non-native to the country of study. The majority of records originated from Asia (35%), with available evidence for 23 CICES classes, as well as Europe (29%) and North America (23%), where research was largely focused on 'biomonitoring'. Whilst the earliest record (from 1949) originated from North America, since 2000, annual output of records has increased rapidly in Asia and Europe. Future research should focus on filling gaps in knowledge in lesser-studied regions, including Africa and South America, and should look to provide a quantitative valuation of the socio-economic costs and benefits of ecosystem services shaped by freshwater bivalves.

Enantioselective metabolism of phenylpyrazole insecticides by rat liver microsomal CYP3A1, CYP2E1 and CYP2D2

The stereoselective difference of chiral pesticide enantiomers is an important factor of risk evaluation and the subject has received wide attention. In the present work, enantioselective metabolism of chiral phenylpyrazole insecticides including fipronil, ethiprole and flufiprole in rat liver microsomes was investigated in vitro. The result showed remarkable enantioselectivity for fipronil and ethiprole with the EF values of 0.11-0.58. The metabolite fipronil-sulfone was formed with the degradation of fipronil. R-Ethiprole to S-ethiprole transformation was observed, but not S-ethiprole to R-ethiprole. No enantioselective metabolism was observed for flufiprole with the EF values of 0.49-0.51. The enzymatic assays showed that the inhibition ratio of R-fipronil and S-ethiprole was 1.5-2.1times that of the corresponding enantiomers on CYP2E1 and CYP2D2 activity, leading to the enantioselective metabolism. The result of the homology modeling and molecular docking further revealed that S-fipronil (-7.56 kcal mol^-1) and R-ethiprole (-6.45 kcal mol^-1) performed better binding with CYP2E1 and CYP2D2, respectively. The results provided useful data for the risk evaluation of chiral phenylpyrazole insecticides on ecological safety and human health.

Assessment of carbamazepine acute toxicity in the cockle Cerastoderma edule through chemical, physiological and biochemical tools

The cockle Cerastoderma edule was exposed to four concentrations (5, 10, 20 and 70 μg L-1) of carbamazepine (CBZ). This anticonvulsant was found to alter the mussel behavior of by reducing its clearance rate (CR). Analysis of CBZ accumulation in tissues of C. edule was carried out using HPLC-UV after 48 or 96 hours of exposure. In addition, an overproduction of H2O2 by the bivalves was detected following exposure to CBZ but nitrite levels remained unchanged. Moreover, superoxide dismutase and catalase activities showed a significant increase in relation to their contact with CBZ. The activity of the biotransformation enzyme gluthatione-S-transferase did not change during exposure. Malondialdehyde (MDA) levels indicating cellular damage, increased when bivalves were exposed to 20 and 70 μg l-1 of carbamazepine for 96 h CBZ. The results also indicate that acetylcholinesterase activity (AChE) was inhibited in all CBZ concentrations during the 48 h exposure period. However, during the 96 h exposure period, AChE was only inhibited at the highest concentration. Further studies are needed now for more exploration of the toxicity of CBZ since it could be bioaccumulable throughout the food web and may affect non-target organisms.

Cypermethrin- and fipronil-based insecticides cause biochemical changes in Physalaemus gracilis tadpoles

Insecticides used for agricultural pest control, as cypermethrin-based insecticide (CBI) and fipronil-based insecticide (FBI), are constant threats to non-target aquatic organisms. This study aimed to investigate the effect of different concentrations of cypermethrin and fipronil on neurotoxicity and oxidative stress in Physalaemus gracilis. Physalaemus gracilis tadpoles were exposed to five insecticide concentrations and a control treatment, with six replicates. During the experimental period, the tadpole mortality rate was evaluated and after 168 h, the neurotoxic enzyme activity and metabolite quantification related to the antioxidant system were measured. Tadpoles reduced acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities when exposed to 20 μg L^-1 CBI and at all FBI concentrations, respectively. Glutathione S-transferase (GST) and superoxide dismutase (SOD) activities showed an increase from concentrations of 6 μg L^-1 and 20 μg L^-1 of CBI, respectively. After exposure of P. gracilis tadpoles to FBI, inhibitions of AChE and BChE were observed at the highest concentrations evaluated (500 and 1500 μg L^-1). SOD activity decreased from 50 μg L^-1 of FBI; however, catalase (CAT) and GST activities and carbonyl protein levels increased, regardless of the evaluated dose. We observed that both insecticides promoted oxidative stress and neurotoxic effects in P. gracilis tadpoles. These results suggest that biochemical biomarkers can be used for monitoring toxicity insecticides for the purpose of preservation of P. gracilis.

Facile synthesis of Cu-doped ZnO nanoparticle in triethyleneglycol: photocatalytic activities and aquatic ecotoxicity

A new synthetisis method of Cu-doped ZnO nanoparticles is presented in this work, this novel approach allow one to produce Zinc oxide nanocristal owing to a modified Polyol process that makes use of triethyleneglycol (TREG) as a solvent. The structure and morphology of the nanoparticles were characterized by high-resolution transmission electron microscopy (HRTEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N₂ adsorption study, UV-Vis diffuse reflectance spectroscopy, inductively coupled plasma optical emission spectroscopy and Raman spectroscopy. The lightly doped Zn_1-xCu_xO photocatalysts consisted in a novel nanorods structure of Zn_0.9990Cu_0.0010O nanoparticles. Taking the photocatalytic degradation of diuron under solar light as liquid phase test reaction, the lightly doped Zn_0.9990Cu_0.0010O nanorods photocatalysts showed strongly enhanced photocatalytic activity when compared to the bare ZnO counterpart. The apparent rate constant value of Zn_0.9990Cu_0.0010O was 22 times higher than that of pure ZnO. In order to study the environmental risk of Cu-ZnO, clams Ruditapes decussatus were exposed to Cu-ZnOC1 = 0.5 mg/L, Cu-ZnOC2 = 1 mg/L and Cu-ZnO C3 = 5 mg/L. Catalase (CAT) activities, malondialdehyde (MDA) content and acetylcholinesterase (AChE) activity were determined in gills and digestive gland of treated and untreated clams. Thus, no significant effects were detected in the gills of exposed clams after 7 days compared to control. Thus, MDA level and CAT activity showed significant differences in digestive glands of groups treated by the highest concentration of Cu-ZnO NPs compared to the control. No adverse effects on AChE activity was detected after Cu-ZnO NPs exposure. These results demonstrated that, although Cu-ZnO NPs is not acutely toxic to Ruditapes decussatus, it does exert oxidative stress on clams. These results are encouraging for the Cu-ZnO NPs use in variety of applications due to its high photocatalytic and low environmental toxicity.

Ecotoxicology and environmental safety toxicity of pyrethroid cypermethrin on the freshwater snail Chilina parchappii: Lethal and sublethal effects

The aim of the present work was to study the effect of the pyrethroid cypermethrin (CYP) on the non-target freshwater snail Chilina parchappi. Initially, the sensitivity of adult snails to CYP was evaluated via the 96-h LC₅₀ test. Then, snails were exposed to subtethal CYP concentrations (0.1 and 10 mg/l) for 1, 4 and 10 days and the digestive glands were dissected for biomarkers analyses. Enzymatic activity of catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST), as well as total glutathione reduced (GSH) levels, were determined. Histological analyses of morphology, intracellular accumulation of lipofucsins and neutral lipids accumulation in the digestive gland were also evaluated. As compared to other molluscs, C. parchappi showed high resistance to CYP exposure evidenced by the 96-h LC₅₀ value (44.59 mg/l). Snails exposed to sublethal CYP concentrations showed a statistically significant increase (p < 0.01) in GST (79-116%) and GPx (45-190%) activities with respect to controls. However, CAT activity showed a tendency to decrease with CYP treatment but was not statistically significantly different compared to control. Only high CYP concentration caused a statistically significant increase (p < 0.01) in GSH content (95-196%). There was evidence of structural changes in the digestive gland of snails exposed to CYP, showing a dose-dependent response. In exposed snails, some of the main symptoms included a reduction in the thickness of the epithelium, vacuolisation of the digestive cells and an increase in the number of excretory cells. Accumulation of lipofuscins (933-1006%) and neutral lipids (403%) were statistically significantly higher (p < 0.05) in snails exposed to CYP compared to control. This study showed that C. parchappii is quite tolerant to CYP exposure and that at sublethal concentrations, GSH metabolism could play a protective role against the pesticide harm in snails. Therefore, it would be interesting to study the response of this organism to other environmental stressors to assess its potential use in monitoring programs.

Adverse effects of a synthetic pyrethroid insecticide cypermethrin on life parameters and antioxidant responses in the marine copepods Paracyclopina nana and Tigriopus japonicus

To find the adverse effects induced by cypermethrin, the ecotoxicological model copepods Tigriopus japonicus and Paracyclopina nana were exposed under cypermethrin, which is a widely used type-II pyrethroid insecticide in agriculture. Despite its large-scale application as insecticide in agriculture, little information is available on its adverse effects on aquatic invertebrates. In this study, the toxicity of cypermethrin on two copepods was assessed based on life parameters (growth rate and reproduction), oxidative stress and consequent antioxidant enzymatic activities, and gene expression profiles of antioxidants. The acute toxicity alone demonstrated that P. nana is less tolerant and sensitive against cypermethrin, compared to T. japonicus. However, under chronic exposure, life parameters of both P. nana and T. japonicus were severely affected by cypermethrin. Among antioxidant enzymatic activities, superoxide dismutase (SOD) and glutathione S-transferase (GST), in particular, demonstrated significant increase in response to cypermethrin. Furthermore, temporal-mRNA expression profile showed modulations in antioxidant related genes in response to cypermethrin. Our results provide the underlying toxic mechanism of cypermethrin and the oxidative stress defense mechanism and species-specific tolerance against cypermethrin in two model copepods species.

Differential response between histological and biochemical biomarkers in the apple snail Pomacea canaliculata (Gasteropoda: Amullariidae) exposed to cypermethrin

To develop effective programs to monitor water quality is necessary to identify sensitive biomarkers in indicator species. The aim of this study was to evaluate different biomarkers in the apple snail Pomacea canaliculata exposed to the insecticide Cypermethrin (CYP). Adult male and female snails were exposed to sublethal CYP concentrations (10, 25 and 100μgl^-1) for 1, 4, 7 and 14days. The recovery of the exposed snails was also studied by a post-exposure assay. The activities of the enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST), the levels of lipid peroxidation (LPO) and protein oxidation (PC) in digestive gland and gills were studied as biomarkers of exposure. Histopathological changes in target tissues were also evaluated. In digestive gland, CYP caused a significant increase in SOD, CAT and GST activities compared to control (p<0.05) as well as in LPO and PC levels (p<0.05). However, such biochemical effects were neither concentration nor time dependent. Histopatological changes were observed in the exposed groups, such as an increase in the number of basophilic cells, hemocytic infiltration and epithelia atrophy. Additionally, a positive correlation between the surface occupied by pigmented corpuscles and CYP concentrations was observed at all exposure periods. Gills showed greater sensitivity to oxidative damage than digestive gland. CYP caused an acute toxic effect in LPO levels in this respiratory organ. The gill filament of exposed snails, exhibited a reduction or loss of cilia, vacuolization of the columnar cells and an increase in haemocyte content irrespective of the concentration. High concentrations of CYP caused disruptions in the columnar muscle fibers. In general, snails did not show an improvement in their basal state during post-exposure treatment. Apparently, males and females do not have differential sensitivity to the pesticide. The results of this study suggest that histopathological changes are the most sensitive time- and dose-dependent biomarkers of toxicity induced by CYP in P. canaliculata.

Pyrethroids in chicken eggs from commercial farms and home production in Rio de Janeiro: Estimated daily intake and diastereomeric selectivity

In this study, pyrethroids were determined in chicken eggs from commercial farm (n = 60) and home egg production (n = 30). These pyrethroids were investigated: bifenthrin, phenothrin, permethrin, cyfluthrin, cypermethrin and fenvalerate, including most diastereomers. Quantification was done using GC-MS in a negative chemical ionization mode. Pyrethroids residues were found in 79% of the analyzed samples. Cypermethrin presented the highest occurrence, being quantified in 62 samples (69%) in concentrations (lipid weight - l w.) varying between 0.29 and 6408 ng g^-1, followed by phenothrin (24%), 21-3910 ng g^-1, permethrin (14%), 2.96-328 ng g^-1, and bifenthrin (11%), 3.77-16.7 ng g^-1. Cyfluthrin and fenvalerate were not detected. Home-produced eggs had a higher occurrence of pyrethroids (97%), with a greater predominance of phenothrin. In commercial production, 70% of the samples presented pyrethroid residues (predominantly cypermethrin). This is the first report about the presence of pyrethroids in home-produced eggs and the first description of a selectivity pattern with the predominance of cis diastereomers in chicken eggs. In general, estimated daily intake does not present a risk to human consumption, according to Brazilian and international standards (FAO/WHO). However, one third of the samples (30 eggs) had concentrations above the maximum residue limits (MRLs). The maximum cypermethrin concentration was 66 times the MRL, while the maximum phenothrin concentration was 11 times the limit. Further studies about transfer dynamics, bioaccumulation and metabolic degradation of stereoisomers are required, as well as determining if this selectivity pattern in food can increase consumer's health risk.