Mechanism of Neonicotinoid Toxicity: Impact on Oxidative Stress and Metabolism

Effects of neonicotinoid pesticide exposure in the first trimester on gestational diabetes mellitus based on interpretable machine learning

BACKGROUND

Gestational diabetes mellitus (GDM) is one of the most common pregnancy complications and seriously threatens the health of mothers and offspring. Neonicotinoids (NEOs) is a new class of pesticide and widely used worldwide. Prenatal NEOs exposure had negative effects on fetal growth, but the potential effect of NEOs exposure on pregnancy complications remain unclear.

OBJECTIVES

To examine the individual and jointed effects of serum neonicotinoids (NEOs) pesticide exposure on gestational diabetes mellitus (GDM), and explore the application of NEOs exposure levels as predictor of GDM.

METHODS

We conducted a prospective cohort study based on Guangxi Zhuang Birth Cohort, China. A total of 1450 mather-infant pairs were included from 2015 to 2019. Ten NEOs were measured by UPLC-MS. Maternal serum samples were collected during gestational age 0-12 weeks. Individual and jointed effects of NEOs on GDM were assessed through binomial regressions, Bayesian Kernel Machine Regression and quantile g-computation. Prediction of GDM using XGboost machine learning and SHapley Additive exPlanations (SHAP).

RESULTS

A total of 122 (8.4%) mothers were diagnosed with GDM. In the individual exposure models, sulfoxaflor and thiamethoxam exposure in the first trimester significantly increased the risk of GDM (OR = 1.48, 95%CI: 1.21, 1.82; OR = 1.42, 95%CI: 1.14, 1.78). Moreover, GDM risk increased significantly with NEOs mixture concentration was above 75th percentile, compared with the 50th percentile. Sulfoxaflor and thiamethoxam as the main positive contributing factors in NEOs mixture to increase the GDM with a weight of 29.3% and 27.6%, respectively. Furthermore, sulfoxaflor and thiamethoxam were the most important contributing factors for predicting GDM after combining traditional risk factors in machine learning model, with predicted contribution values of 0.79 and 0.46, respectively.

CONCLUSION

Our findings suggested that elevated maternal serum sulfoxaflor, thiamethoxam and NEOs mixture were positively associated with GDM, and sulfoxaflor, thiamethoxam were the important contributing factors for predicting GDM.

Human plasma protein bindings of neonicotinoid insecticides and metabolites

Neonicotinoid insecticides (neonicotinoids) are widely used in agriculture, forestry and public health in the world. Environmental exposure to neonicotinoids has been increasing due to their continuous uses. Neonicotinoids act as agonists, antagonists, or modulators of acetylcholine receptors and have adverse effects on non-target species, such as invertebrates, amphibians, reptiles, birds, microbes and mammals. Although there is concern about their adverse effects on ecosystem services and their potential effects on human health, their xenobiotic kinetics and dynamics in humans are not understood well. In this study, we determined a xenobiotic kinetic parameter, plasma protein bindings (PPBs) of 7 neonicotinoids and 18 metabolites with human plasma using a Rapid Equilibrium Dialysis (RED) device and liquid chromatography-tandem mass spectrometry (LC-MS/MS), and compared their PPBs with their physicochemical properties. 6-chloronicotinic acid (6-CNA) exhibited the highest PPB (86.4%), followed by imidacloprid-olefin (86.3%) in human plasma. Their PPBs are much higher than that of the parent compound, imidacloprid (27.5%). The PPBs of neonicotinoids and metabolites are not related to their lipophilicity determined by reversed-phase LC. The results shed light on the behavior of environmentally exposed neonicotinoids and metabolites and warrant further research on their xenobiotic kinetics and dynamics in humans.

Differentiated distribution between albumen, yolk and eggshell of parents and metabolites neonicotinoids and their reproductive exposure risk

Differential distribution of neonicotinoids (NEOs) in albumen, yolk, and eggshell is a critical factor influencing their bio-accumulative behavior and the subsequent human health risks. However, there is currently no relevant research available. We collected 62 egg samples from 31 sampling sites across China and analyzed the concentrations and characteristics of 12 parents NEOs (p-NEOs) and 8 metabolites NEOs (m-NEOs) in albumen, yolk, and eggshell. NEOs were frequently detected in differentiated egg matrices, with the highest concentrations observed in Northeast China. The concentrations of m-NEOs were generally higher than those of p-NEOs. A positive correlation was found between the distribution of m-NEOs in albumen and their logKow (p < 0.05). Dietary intake exposure posed a higher risk of NEOs to children and females. The toxicity equivalence (TEQ) of 5-hydroxy-imidacloprid and thiacloprid-amide, in interaction with androgen and estrogen receptors, was higher compared to other NEOs. Network toxicology and molecular docking indicated that AKT1 may serve as the core target for reproductive toxicity induced by dinotefuran, cycloxaprid, and nitenpyram exposure. This study provided valuable data on the occurrence, differential distribution, and reproductive exposure risk of NEOs in eggs for the first time. These findings are instrumental for future management policies concerning the environmental behavior and health effects of NEOs.

Clothianidin Exposure Induces Cell Apoptosis via Mitochondrial Oxidative Damage

Clothianidin (CLO) is a high-frequently detected neonicotinoid pesticide in fruits and vegetables, whose exposure security deserves attention. This study evaluated the apoptotic toxicity of CLO on Caco-2 cells at doses of 100 nM, 10 μM, and 1 mM. After exposure, CLO induced to a remarkable change of signaling proteins that participated in the process of cell apoptosis, including caspase 3, cleaved-caspase 3, and caspase 9. CLO treatment further induced a decrease of mitochondrial membrane potential and increased the protein level of cytochrome C. Reactive oxygen species (ROS) and intracellular Ca2+ were also found elevated, indicating an oxidative damage caused by CLO treatment. Moreover, the production of ROS occurred in advance of Ca2+ elevation, since inhibiting ROS production could recover the elevation of Ca2+ induced by CLO exposure. The protein level of metabolic enzyme cytochrome P450 3A4 (CYP3A4) was downregulated after the treatment of CLO. Molecular docking simulation indicated that CLO had good binding characteristics with CYP3A4. Amino acid sites Arg105, Arg130, and Leu373 in CYP3A4, and nitro group and chlorothiazole group in CLO structure might be the potential binding action target. These results indicated that CLO exposure could induce an apoptotic effect on Caco-2 cells, possibly acting through combining and inhibiting its metabolic enzyme CYP3A4, and then leading to oxidative stress and mitochondrial damage. Thus, CLO exposure might be a potential risk factor for human intestinal health.

Acute and chronic pesticide exposure trigger fundamentally different molecular responses in bumble bee brains

BACKGROUND

Beneficial insects, including pollinators, encounter various pesticide exposure conditions, from brief high-concentration acute exposure to continuous low-level chronic exposure. To effectively assess the environmental risks of pesticides, it is critical to understand how different exposure schemes influence their effects. Unfortunately, this knowledge remains limited. To clarify whether different exposure schemes disrupt the physiology of pollinators in a similar manner, we exposed bumble bees to acute or chronic treatments of three different pesticides: acetamiprid, clothianidin, or sulfoxaflor. Genome-wide gene expression profiling enabled us to compare the effects of these treatments on the brain in a high-resolution manner.

RESULTS

There were two main findings: First, acute and chronic exposure schemes largely affected non-overlapping sets of genes. Second, different pesticides under the same exposure scheme showed more comparable effects than the same pesticide under different exposure schemes. Each exposure scheme induced a distinct gene expression profile. Acute exposure mainly caused upregulation of genes linked to the stress response mechanisms, like peroxidase and detoxification genes, while chronic exposure predominantly affected immunity and energy metabolism.

CONCLUSIONS

Our findings show that the mode of exposure is critical in determining the molecular effects of pesticides. These results signal the need for safety testing practices to better consider mode-of-exposure dependent effects and suggest that transcriptomics can support such improvements.

Evaluation of the concentrations of current use pesticides (CUPs) in urban air and rainfall, and their wet deposition flux in a metropolitan environment

This study assesses the wet deposition fluxes and washout ratios of current-use pesticides (CUPs) in Bursa, Turkey, to better understand their environmental impact. It investigates the temporal and spatial fluctuations of these compounds, particularly focusing on CUPs like benomyl, dichlorvos, dimethoate, imidacloprid, monochrotophos, and pymetrozine. The concentrations of CUPs in both ambient air and precipitation showed seasonal variations, with peaks in spring and summer due to increased agricultural activities. Precipitation concentrations of CUPs also varied, when the detection rates based on CUP congeners are analyzed, benomyl (70 %) and pymetrozine (66 %) are the most frequently detected congeners in the collected samples, particularly during the peak agricultural season. Wet deposition fluxes were highest in spring and summer, while dry deposition fluxes peaked in autumn and winter. Benomyl, dichlorvos, dimethoate, and imidacloprid were determined the most abundant CUP congeners in both phase (gas and particle phase). The dry deposition velocities ranged from 0.001 to 2.26 cm/s, and washout ratios varied between 1.35 × 10-4 and 1.18 × 10-6, depending on the CUP congeners. These findings underscore the need for ongoing monitoring, enhanced measurement techniques, and interdisciplinary collaboration to better understand CUP distribution and its environmental and health impacts, while developing effective management strategies.

Synergistic neurotoxicity of clothianidin and photoaged microplastics in zebrafish: Implications for neuroendocrine disruption

Microplastics (MPs), widely found in aquatic environments, pose a growing threat to environmental and biological health due to their complex interactions with pollutants and microorganisms. This study investigates the adsorption characteristics of clothianidin (CLO) on polystyrene (PS) and photoaged polystyrene (P-PS) and explores the neurotoxic effects of CLO combined with PS/P-PS in larval zebrafish (Danio rerio). Adsorption kinetics and isotherms showed that P-PS exhibited a higher adsorption capacity and faster equilibrium compared to PS, indicating the significant role of photoaging in enhancing CLO adsorption. Exposed to CLO combined with PS/P-PS resulted in reduced locomotor activity, particularly in the P-PS + CLO group, suggesting amplified neurotoxicity due to P-PS. Analysis of the hypothalamic-pituitary-interrenal (HPI) axis revealed elevated levels of adrenocorticotropic hormone (ACTH) and cortisol, along with downregulated expression of stress-related genes in co-exposed zebrafish, indicating disruption of neuroendocrine function. Neurotransmitter analysis showed significant changes in acetylcholine (ACh), dopamine (DA), serotonin (5-HT), and γ-aminobutyric acid (GABA) levels, further confirming the neurotoxic impact of co-exposure. The findings highlight the synergistic neurotoxicity of CLO and photoaged MPs, with potential implications for aquatic ecosystems. This study advances the field of environmental science by addressing critical knowledge gaps in pollutant-microplastic interactions, providing a foundation for developing targeted mitigation strategies and enhancing ecological risk management frameworks.

Insights into the mobility and bacterial hosts of antibiotic resistance genes under dinotefuran selection pressure in aerobic granular sludge based on metagenomic binning and functional modules

Dinotefuran (DIN) is toxic to non-target organisms and accelerates the evolution of antibiotic resistance, which poses a problem for the stable operation of the activated sludge process in wastewater treatment plants (WWTPs). However, the emergence and the transfer mechanism of antibiotic resistance genes (ARGs) in activated sludge systems under DIN stress remains unclear. Thus, in the study, the potential impact of DIN on ARGs and virulence factor genes (VFGs) in aerobic granular sludge (AGS) was investigated in depth using metagenomic binning and functional modules. It was found that DIN stress increased the total abundance of ARGs, mobile genetic elements (MGEs), and VFGs in the AGS system, with the highest abundance of fabG (4.6%), tnpA (55.6%) and LPS (39.0%), respectively. The proliferation of the enteric pathogens Salmonella enterica and Escherichia coli in the system indicates that DIN induces exposure of harmless bacteria to the infected environment. The genera Nitrospira (1169 ARG subtypes) and Dechloromonas (663 ARG subtypes) were identified as the potentially antibiotic-resistant bacteria carrying the most ARGs and MGEs in the metagenome-assembled genomes. Co-localization patterns of some ARGs, MGEs, and the SOS response-related gene lexA were observed on metagenome-assembled contigs under high levels of DIN exposure, suggesting DIN stimulated ROS production (101.8% increase over control), altered cell membrane permeability, and increased the potential for horizontal gene transfer (HGT). Furthermore, the DNA damage caused by DIN in AGS led to the activation of the antioxidant system and the SOS repair response, which in turn promoted the expression of the type IV secretion system and HGT through the flagellar channel. This study extends the previously unappreciated DIN understanding of the spread and associated risks of ARGs and VFGs in the AGS system of WWTPs. It elucidates how DIN facilitates HGT, offering a scientific basis for controlling emerging contaminant-induced resistance.

Urinary neonicotinoid exposure and its association with hypertension and dyslipidemia among the elderly: A cross-sectional study in Shenzhen, China

In recent years, neonicotinoids (NEOs) as a new type of insecticide have been increasingly used worldwide, causing significant impacts on human health. This study collected urine samples from 1147 elderly individuals (including 714 in the control group and 433 in the hypertension group) in Shenzhen, China, and detected the concentrations of six types of NEOs and four metabolites of NEOs (mNEOs). The aim of this study is to investigate the association between NEOs exposure and hypertension and dyslipidemia. After measurement, we find that the lowest detection rate (DR) among NEOs is imidacloprid (IMI), at only 39.3%. The NEO with the highest urine median concentration is dinotefuran (DIN) (1.31 μg/L), while the mNEO with the highest median concentration is DM-ACE (2.74 μg/L). Through univariate analysis, we found that DM-THM may promote the development of hypertension, while logistic regression indicated that IMI-OF could be a risk factor for hypertension. As prototypes of these two metabolites, thiamethoxam (THM) and IMI may also be risk factors for hypertension. Linear regression analysis revealed a negative correlation between the concentration of thiamethoxam (THD) and low-density lipoprotein (LDL) level, while DIN was positively correlated with triglyceride (TG) level and negatively correlated with high-density lipoprotein (HDL) level. Mediation effect analysis showed that THD may influence the risk of hypertension in the elderly by affecting LDL level. Based on this study, we believe that exposure to NEOs may increase the risk of hypertension in the elderly population.

Associations between neonicotinoids and inflammation in US adults using hematological indices: NHANES 2015-2016

Background

Toxicological studies suggest neonicotinoids increase oxidative stress and inflammation, but few epidemiological studies have explored these effects.

Methods

National Health and Nutrition Examination Survey (NHANES) 2015-2016 data were used to estimate associations between neonicotinoid exposure and inflammatory markers, including the C-reactive protein-to-lymphocyte count ratio (CLR), monocyte-to-high-density lipoprotein ratio (MHR), monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte ratio (NLR), derived NLR (dNLR), lymphocyte-to-monocyte ratio, platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) using linear and multinomial logistic regression models. Sex was evaluated as a potential modifier.

Results

Detection of any parent neonicotinoid (β = -0.62, 95% confidence interval [CI] = -0.98, -0.26) and imidacloprid (β = -0.48, 95% CI = -0.87, -0.10) was associated with decreased CLR. Clothianidin was linked to reduced MLR (β = -0.04, 95% CI = -0.07, -0.02), but increased lymphocyte-to-monocyte ratio (β = 0.52, 95% CI = 0.27, 0.77). Higher dNLR (β = 0.85; 95% CI = 0.26, 1.43) was noted with detection of any neonicotinoid metabolite. Moderately high PLR was observed with detection of any neonicotinoid metabolite (relative risk ratio [RRR] = 1.63, 95% CI = 1.27, 2.09) or 5-hydroxy-imidacloprid (RRR = 2.19, 95% CI = 1.40, 3.41). Sex-modified analyses showed positive associations in males and inverse associations in females for MHR (P int = 0.099, clothianidin), PLR (P int = 0.026, clothianidin), and SII (P int = 0.056, any parent neonicotinoid; P int = 0.002, clothianidin), while the opposite pattern was noted with CLR (P int = 0.073, any parent neonicotinoid) and NLR (P int = 0.084, clothianidin).

Conclusion

Neonicotinoids may be associated with inflammatory changes, with potential sexual dimorphism. Further studies are required to explore these findings.

The impact of neonicotinoid pesticides on reproductive health

Neonicotinoids are some of the most widely used insecticides in the world because they broadly target chewing and sucking insects. Neonicotinoids are used in commercial agricultural systems, sold for use in home gardens, and found in veterinary pharmaceuticals in the form of flea and tick preventatives for companion animals. They are also used as crop seed treatments and spread throughout crops as they mature. As a result, humans, wildlife, livestock, and pets are routinely exposed to neonicotinoids through the consumption of contaminated food and water as well as through the use of some veterinary pharmaceuticals. Although several studies indicate that neonicotinoid exposure causes genotoxicity, neurotoxicity, hepatotoxicity, and immunotoxicity in some non-target species, the impact of neonicotinoid pesticides on the male and female reproductive systems in mammals is largely understudied. This review summarizes current insights on the impact of common neonicotinoid pesticides such as acetamiprid, clothianidin, imidacloprid, and thiacloprid on male and female reproductive health in mammals. The review also summarizes the impacts of exposure to mixtures of neonicotinoids on reproductive endpoints. In addition, this review highlights where gaps in research on neonicotinoid pesticides and reproductive health exist so that future studies can be designed to fill current gaps in knowledge.

Investigation of the therapeutic effect of melatonin on deltamethrin applied mouse primary hepatocyte culture

OBJECTIVE

In recent years, it has been known that the melatonin hormone, secreted from the pineal gland, possesses significant antioxidant activity. This study explores the therapeutic effect of melatonin on the deleterious effects of deltamethrin, a pyrethroid pesticide extensively used worldwide, including in Türkiye, on mouse liver cells.

METHODS

Hepatocytes from Balb/C mice were isolated using a two-stage perfusion method, resulting in over 85% live hepatocytes. The isolated cells were cultured with different doses of deltamethrin (1 and 10 µM) and melatonin (100 µM) for 24 and 48 hours. At the conclusion of the culture period, hepatocytes were extracted at the 24th and 48th hours, and Malondialdehyde (MDA), Total Antioxidant Capacity (TAC), Total Oxidation Status (TOS), and DNA damages (8-hydroxy-2'-deoxyguanosine (8-OHdG)) were examined.

RESULTS

While an increase in MDA, TOS, and DNA damage was observed in the deltamethrin-administered groups of hepatocytes, a decrease in TAC level was noted. It was determined that the applied deltamethrin had no effect on cell viability throughout the application period.

CONCLUSION

Furthermore, it was observed that melatonin, when administered concurrently with deltamethrin, reduced the toxic effect of deltamethrin. This study suggests that melatonin has a protective effect against deltamethrin-induced damage in mouse hepatocyte cells.

Exposure of Apis mellifera (Hymenoptera: Apidae) colonies to imidacloprid impairs larval development, promotes oxidative stress in pupae, and induces changes in the midgut of adult bees

Bees are essential pollinators that contribute to maintaining biodiversity and increasing agricultural production. However, by foraging on agricultural crops, bees may become contaminated with compounds used for pest control. In this study, we exposed bee (Apis mellifera L.) colonies to the insecticide imidacloprid (IMD) under field conditions to assess the occurrence of oxidative stress in larvae and pupae and investigate morphological changes in the fat body and midgut of larvae and midgut of adult bees. The apiary area was divided into three groups: control, commercial formulation containing IMD (Evidence® 700WG) (IMDCF), and IMD active ingredient (Sigma-Aldrich) (IMDAI). Treatment groups were fed syrup containing 1 µg L-1 IMD, whereas the control group was fed syrup only. Compared with the control, larvae exposed to IMDCF or IMDAI for 42 days exhibited morphological changes in the external body, midgut, and fat body. The midgut of adult bees contaminated with IMDCF showed only structural remnants of the peritrophic membrane and absence of regenerative cell nests. Oxidative stress analyses revealed that IMDCF-exposed larvae had higher nitrite and carbonylated protein contents and lower catalase and superoxide dismutase activity than control individuals. In pupae, IMDAI decreased catalase activity while increasing superoxide dismutase activity. These findings indicate that IMD has the potential to significantly impact the development of bees and their colonies by disrupting vital organs responsible for normal physiological functioning and overall activities of individuals. Oxidative stress, which was detected at different stages of bee development, may induce lipid, protein, and DNA oxidation, leading to cell death.

Evaluating the impact of neonicotinoids on aquatic non-target species: A comprehensive review

Neonicotinoid insecticides (NNIs) are the fastest-growing class in agricultural protection. They target nicotinic acetylcholine receptors (nAChR) in pests, stimulating the nervous system at low doses and causing paralysis and death at higher concentrations. NNIs are used in crop protection, seed treatment, forestry, agriculture, and flea control in domestic cattle. Effective at lower concentrations and offering long-term control, NNIs are favoured for their systemic activity. However, due to their water solubility, mobility, and moderate persistence, NNIs easily contaminate adjacent aquatic environments via runoff, leaching, or spray drift. While less toxic to vertebrates, their widespread use poses threats to aquatic and terrestrial organisms, causing neurotoxicity, nephrotoxicity, cytotoxicity, genotoxicity, immunotoxicity, hepatotoxicity, endocrine disruption, and reproductive malformations. This review synthesizes research to address knowledge gaps on the environmental impact of NNIs and proposes policies to mitigate their harmful effects on aquatic non-target species.

Evidence for the formation of 6PPD-quinone from antioxidant 6PPD by cytochrome P450

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) as a rubber antioxidant has attracted global concern, since its ozone-oxidation product 6PPD-quinone (6PPDQ) was found to be the primary toxicant responsible for urban runoff mortality syndrome in coho salmon. However, the biotransformation fate and associated toxicological mechanism of 6PPD have not received much study yet. In this work, the in vitro assays showed 6PPD can be transformed into 6PPDQ by cytochromes P450 (CYP450) in human liver microsomes (HLMs) with 0.98 % production rate, and the adducts of 6PPDQ with calf thymus DNA and the N-N coupling product between 6PPD and 6PPDQ were further identified after 6PPD incubation in HLMs. Further evidence for the 6PPDQ formation can be obtained from the in vivo assays that the 6PPDQ-DNA adducts and 6PPD-N-N-6PPDQ dimer were detected in mice by oral gavage with 6PPD, and the latter dimer species was detected as well in 6PPD exposure to zebrafish larvae. Especially, the bioaccumulation property and high reactivity of 6PPDQ result in the continuous formation of the significant DNA adducts and 6PPD-N-N-6PPDQ dimer even in case of low production rate of biotransformation of 6PPD to 6PPDQ, which may provide potentially effective biomarkers for such process. DFT computations revealed the formation mechanism of 6PPDQ is the (N)H-abstraction of 6PPD by CYP450, followed by amino radical rebound at the nearby ortho-carbon, yielding a quinol intermediate due to spin delocalization, that might readily undergo further oxidation by CYP450 into 6PPDQ.

Function Analysis of Heme Peroxidase Genes, MpPxd2 and MpPxd4, Under Thiacloprid Exposure in the Neonicotinoid-Resistant Myzus persicae (Sulzer)

The green peach aphid, Myzus persicae, is a notorious pest worldwide. We collected a field population of the pest (FZQ-F) that exhibited high resistance to neonicotinoids. Exposure to neonicotinoids can induce oxidative damage in animals; however, it remains unclear whether antioxidant enzymes contribute to the innate immune response of neonicotinoid-resistant pests against high doses of insecticides. Treatment with sublethal doses of thiacloprid (LC10 and LC25) for 3, 6, 12, 24, 48, and 72 h resulted in significantly increased reactive oxygen species (ROS), including H2O2 content, in FZQ-F adults, indicating insecticide-induced oxidative stress. Additionally, the peroxidase activity in FZQ-F adults increased after thiacloprid exposure. Using comparative genomics, we identified 31 heme peroxidases in M. persicae with a typical "2Cys" structure, and phylogenetic analyses divided them into five groups. Comparative transcriptomes revealed that MpPxd2 and MpPxd4 were significantly upregulated in thiacloprid-treated aphids. Thiacloprid exposure significantly induced MpPxd2 and MpPxd4 expression levels, consistent with high H2O2 content and peroxidase activity. The knockdown of MpPxd2 or MpPxd4 in FZQ-F increased their susceptibility to imidacloprid, thiacloprid, and thiamethoxam, verifying the protective role of the heme peroxidases against neonicotinoids in aphids. The knockdown of MpPxd2 or MpPxd4 also led to shorter longevity and a low fecundity of adult aphids at 31 °C compared to controls. The results show that MpPxd2 or MpPxd4 is important in how cells respond to oxidative stress and may help resistant M. persicae pests to handle neonicotinoids.

Imidacloprid affects human cells through mitochondrial dysfunction and oxidative stress

Given their relatively low persistence and mammalian toxicity, neonicotinoid pesticides have been extensively used worldwide and are omnipresent in the environment. Recent studies have shown that neonicotinoids may pose adverse effects on non-target organisms other than the known neurotoxicity, raising emerging concerns that these insecticides might pose human health risk through additional toxicity pathways. In the present study, the mitochondria function, oxidative stress, DNA damages, and genes transcription levels were examined in the human neuroblastoma SH-SY5Y cells after 48-h exposure to imidacloprid at concentrations from 0.05 to 200 μmol/L. Results showed that imidacloprid induced mitochondrial dysfunction with the degradation of adenosine triphosphate (ATP) and mitochondrial membrane potential (MMP) levels. In addition, imidacloprid caused oxidative stress by stimulating the generation of reactive oxygen species (ROS) and hydrogen peroxide (H2O2) via the disruption of calcium ion level and mitochondrial function. Ultimately, the oxidative stress continued to produce DNA damage and apoptosis in SH-SY5Y cells at imidacloprid concentrations above 47.6 μmol/L. Among the evaluated endpoints, ATP was the most sensitive, with a median activity concentration of 0.74 μmol/L. The 5 % hazard concentration of imidacloprid was estimated to be 0.69 μmol/L, which can be used as a threshold for human health risk assessment for imidacloprid. Collectively, our results provide an important support for further research on potential toxicity of neonicotinoids related to mitochondrial toxicity in humans.

Unraveling the acute sublethal effects of acetamiprid on honey bee neurological redox equilibrium

Understanding the off-target effects of neonicotinoid insecticides, including acetamiprid, which is the most commonly applied agricultural chemical, is crucial as it may be an important factor of negative impact on pollinator insects causing a number of problems such as colony collapse disorder (CCD) of honey bees. While CCD is known as a multifactorial disease, the role of pesticides in this context is not negligible. Therefore, it is essential to gain a deeper comprehension of the mechanisms through which they function. The aim of this research was to study the effects of sublethal acetamiprid doses on honey bees, specifically focusing on the redox homeostasis of the brain. According to our findings, it can be confirmed that acetamiprid detrimentally impacts the redox balance of the brain increasing hydrogen peroxide and malondialdehyde levels, suggesting consequential lipid peroxidation and membrane damage as consequences. Moreover, acetamiprid had negative effects on the glutathione system and total antioxidant capacity, as well as key enzymes involved in the maintenance of redox homeostasis. In summary, it can be concluded that acetamiprid adversely affected the redox balance of the central nervous system of honey bees in our study. Our findings could potentially contribute to a better understanding of pesticide-related consequences and to improvement of bee health.

Sensitivity Variations in Developmental Toxicity of Imidacloprid to Zebrafish Embryos at Different Neurodevelopmental Stages

Neonicotinoids are ubiquitous in global surface waters and pose a significant risk to aquatic organisms. However, information is lacking on the variations in sensitivity of organisms at different developmental stages to the neurotoxic neonicotinoids. We established a spectrum of toxicity to zebrafish embryos at four neurodevelopmental stages (1, 3, 6, and 8 h post fertilization [hpf]) and dechorionated embryos at 6 hpf based on external and internal exposure to imidacloprid as a representative neonicotinoid. Embryos at the gastrula stage (6 and 8 hpf) were more sensitive to imidacloprid than embryos at earlier developmental stages. Dechorionated embryos were more sensitive to imidacloprid than embryos with a chorion, suggesting that the chorion offers protection against pollutants. Nine sublethal effects were induced by imidacloprid exposure, among which uninflated swim bladder (USB) was the most sensitive. Water depth and air availability in the exposure chambers were critical factors influencing the occurrence of USB in zebrafish larvae. Internal residues of metabolites accounted for <10% of imidacloprid, indicating that imidacloprid was metabolized in a limited fashion in the embryos. In addition, acute toxicity of the main metabolite 5-hydroxy-imidacloprid was significantly lower than that of imidacloprid, indicating that the observed toxicity in embryos exposed to imidacloprid was mainly induced by the parent compound. Our research offers a fresh perspective on choosing the initial exposure time in zebrafish embryo toxicity tests, particularly for neurotoxicants. Environ Toxicol Chem 2024;43:2398-2408. © 2024 SETAC.

Insight of neonicotinoid insecticides: Exploring exposure, mechanisms in non-target organisms, and removal technologies

Neonicotinoid insecticides (NEOs) have garnered global attention due to their selective toxicity to insects and minimal impact on mammals. However, growing concerns about their extensive use and potential adverse effects on the ecological environment and non-target organisms necessitate further investigation. This study utilized bibliometric tools to analyze Web of Science data from 2003 to 2024, elucidating the current research landscape, identifying key research areas, and forecasting future trends related to NEOs. This paper provides an in-depth analysis of NEO exposure in non-target organisms, including risk assessments for various samples and maximum residue limits established by different countries. Additionally, it examines the impacts and mechanisms of NEOs on non-target organisms. Finally, it reviews the current methods for NEO removal and degradation. This comprehensive analysis provides valuable insights for regulating NEO usage and addressing associated exposure challenges.

Prenatal exposure to neonicotinoid insecticides, fetal endocrine hormones and birth size: Findings from SMBCS

BACKGROUND

Neonicotinoid insecticides (NNIs) were reported to be endocrine disruptors and cause adverse health effects in human. However, epidemiological evidence about the effect of prenatal NNIs exposure on birth outcome and hormones remains limited.

OBJECTIVES

This study aimed to explore the effects of prenatal NNIs exposure on neonatal birth size and endocrine hormones, and assess the potential mediating role of hormones.

METHODS

The study included 860 mother-child pairs from the Sheyang Mini Birth Cohort Study. 12 parent NNIs (p-NNIs) and 6 metabolites of NNIs (m-NNIs) were measured in maternal urine samples collected on their delivery days, and 5 thyroid hormones and 2 sex hormones were analyzed in cord serum. The concentrations of p-NNIs and its specific metabolite(s) were summed to characterize the role of each class of NNIs. Generalized linear model and weighted quantile sum regression were used to examine the impact of prenatal NNIs exposure on birth size and endocrine hormones, and potential mediating roles of hormones were further explored using mediation analysis.

RESULTS

Higher detection frequencies of m-NNIs were observed than those in p-NNIs. A decrease in neonatal head circumference for gestation age z-score was associated with a 10-fold increase in 5-OH-IMI (β = -0.15, 95 %CI: -0.26, -0.03), ∑DIN (β = -0.22, 95 %CI: -0.40, -0.03), ∑IMI (β = -0.20, 95 %CI: -0.35, -0.06) and ∑NNIs (β = -0.23, 95 %CI: -0.42, -0.04). ∑IMI and ∑DIN were the major contributors to the significantly negative mixture effect and no sex-specific effect was observed. Negative associations were observed between ∑DIN and TT3 (β = -0.013, 95 %CI: -0.025, -0.002), ∑IMI and T (β = -0.035, 95 %CI: -0.065, -0.004), respectively. Furthermore, TT3 and T demonstrated 6.7 % and 6.1 % mediating effects on the negative association of prenatal ∑DIN and ∑IMI exposure with head circumference.

CONCLUSIONS

Our findings suggested the potential endocrine disruptive properties of NNIs and their impacts on head circumference. Endocrine hormones may partly mediate these associations.

Paralysis caused by dinotefuran at environmental concentration via interfering the Ca2+-ROS-mitochondria pathway in Chironomus kiiensis

Introduction

Dinotefuran as the third-generation of neonicotinoid insecticides is extensively used in agriculture worldwide, posing a potential toxic threat to non-target animals and humans. However, the chronic toxicity mechanism related to mitochondria damage of dinotefuran to non-target animals at environmental concentration is unclear.

Methods

In this study, the mitochondria damage and oxidative stress of dinotefuran on Chironomus kiiensis were investigated at environmental concentrations by long-term exposure. At the same time, relevant gene expressions of these toxicity indexes were measured as sensitive ecotoxicity biomarkers to reflect the toxic effects of dinotefuran on Chironomidae.

Results

Our present study showed that chronic exposure to environmental concentrations of dinotefuran resulted in behavioral inhibition in the larvae of Chironomidae. For burrowing inhibition of 10 days, the lowest observed-effect concentration (LOEC) and 50% inhibitory concentration (IC50) were 0.01 (0.01-0.04) and 0.60 (0.44-0.82) μg/L, respectively. Dinotefuran promoted the release of intracellular calcium ions (Ca2+) in Chironomidae via dysregulating the gene expressions of atp2b, camk ii, and calm. Subsequently, the disruption of the Ca2+ signaling pathway induced oxidative stress by raising reactive oxygen species (ROS), hydrogen peroxide (H2O2), and malonaldehyde (MDA) levels. Thus, the over-release of Ca2+ and ROS disordered the normal functioning of mitochondrial-related pathways by dysregulating the expressions of mitochondria-related genes of atpef0a, sdha, and cyt b.

Conclusion

Our findings showed that low environmental concentrations of dinotefuran caused paralysis of the midge via interfering the Ca2+-ROS-mitochondria pathway. These results provided data support for assessing the potential environmental risk of dinotefuran.

Bioaccumulation, transformation and toxicity of imidacloprid and dinotefuran in Eisenia fetida under single and binary exposure scenarios

Earthworms (Eisenia fetida) were exposed to individual and binary mixture of imidacloprid (IMI) and dinotefuran (DIN) at 0.05 and 0.5 mg/kg for 28 days to investigate their bioaccumulation, transformation and toxicity. IMI was more easily absorbed by earthworms than DIN, and worms didn't accumulate or generate toxic metabolites. The obvious accumulation of neonicotinoids during later period caused significant neural dysfunction, especially when exposed to high-concentration IMI. Meanwhile, oxidative stress indicated by decreased SOD/CAT activity (33.2 %-68.1 %) and increased MDA (38.4 %-55.0 %) was induced by binary exposure with high-concentration IMI. By contrast, coelomocytes responded earlier and more strongly than oxidative responses. Coelomocytes' viability and mitochondrial membrane potential were inhibited (23.6 %-91.7 %) mainly by IMI and binary exposure. Coelomocytes' lactate dehydrogenase activity exerted a fluctuating pattern, suggesting irregular disturbance on cellular functions. This study highlights the role of coelomocytes and the need to consider binary/multiple scenarios and transformation of neonicotinoids in their risk assessment to earthworms.

Lysosomal disruption, mitochondrial impairment, histopathological and oxidative stress in rat's nervous system after exposure to a neonicotinoid (imidacloprid)

Imidacloprid (IMI), a neonicotinoid pesticide, has been widely used due to its high efficiency against insect pests. However, its prolonged exposure may pose significant risks to non-target organisms, including mammals. Recent studies have raised concerns about its potential neurotoxicity, yet the underlying mechanisms remain poorly understood. This study aimed to assess the neurotoxic effects of chronic Imidacloprid exposure in Wistar rats, focusing on oxidative stress, mitochondrial dysfunction, and lysosomal disruption. Wistar rats were orally administered two doses of Imidacloprid (5 mg/kg and 50 mg/kg body weight) for three months. Neurotoxic effects were assessed by measuring key biochemical markers such as the enzymatic activities of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), and glutathione S-transferase (GST). Non-enzymatic markers, including glutathione (GSH) levels and malondialdehyde (MDA) index, were also evaluated. Mitochondrial function was assessed by analyzing oxygen consumption, swelling, and membrane permeability and histopathological changes. Lysosomal stability was examined using the Neutral Red Retention Time (NRRT) assay. Neutral red is a dye that accumulates in the acidic environment of lysosomes. Healthy lysosomes retain the dye, while compromised lysosomes lose it, indicating destabilization. By measuring the amount of neutral red retained in lysosomes, the NRRT assay assesses lysosomal integrity. Lysosomal pH variations were also monitored to evaluate functional changes. Microscopic analysis provided insight into structural changes in lysosomes and other cell components. Lysosomal destabilization was further confirmed by morphological alterations observed through light microscopy, revealing a progressive, time-dependent degeneration of lysosomal structures, including lysosomal expansion, neutral red dye leakage, and cell rounding. These changes reflected a temporal evolution of lysosomal damage, progressing from minor structural disruptions to more severe alterations as exposure continued, observable at the microscopic level. During the study, clinical observations of intoxicated rats included symptoms such as lethargy, reduced activity levels, and impaired motor coordination. High-dose Imidacloprid exposure led to noticeable behavioral changes, including decreased exploratory behavior and altered grooming patterns. Additionally, signs of neurotoxic effects, such as tremors or ataxia, were observed in the rats exposed to the higher dose, reflecting the systemic impact of chronic pesticide exposure. The results revealed a significant decrease in the enzymatic activities of CAT, GPx, and SOD, accompanied by an increase in GST activity. A notable reduction in glutathione levels and a rise in MDA index were observed, indicating enhanced oxidative stress in the brain. Mitochondrial impairment was evidenced by disturbances in oxygen consumption, increased swelling, and altered membrane permeability. Lysosomal destabilization was confirmed by reduced retention of neutral red dye, structural changes in lysosomes, and a significant rise in lysosomal pH in the IMI-exposed groups. In addition, the histopathological features indicate that imidacloprid at the given dose and exposure duration may have caused notable neurotoxic effects in Wistar rat brain tissue. Chronic exposure to Imidacloprid induces oxidative stress, mitochondrial dysfunction, lysosomal disruption and histopathological alterations in the central nervous system of Wistar rats. These findings provide valuable insights into the neurotoxic mechanisms of neonicotinoid pesticides, highlighting the need for further research to understand the long-term effects of Imidacloprid exposure on mammalian health.

Physiological and gene expression responses of Protohermes xanthodes (Megaloptera: Corydalidae) larvae to imidacloprid

Megaloptera larvae are important bioindicator species and potential resource insects. To further cultivate their economic role, their living environment must be examined in more detail. In this study, we analyzed the physiological and biochemical effects of a sublethal dose of imidacloprid, a widely used neonicotinoid insecticide, on the larvae of Protohermes xanthodes. After treatment with imidacloprid, P. xanthodes larvae exhibited clear symptoms of poisoning, including the head curling up toward the ventral surface. Additionally, the activity of acetylcholinesterase was significantly inhibited following exposure. The activities of glutathione S-transferases initially continuously increased but showed a slight decrease after 8 days. Catalase activity initially increased and then decreased following imidacloprid treatment; superoxide dismutase activity fluctuated over time, and peroxidase activity continuously increased. The expression levels of HSP70s genes were evaluated using qRT-PCR. These results indicate that P. xanthodes larvae exhibit a toxic response to imidacloprid exposure, manifested as oxidative stress, as observed through behavioral and physiological indicators.

Co-administration of thymol and sulfoxaflor impedes the expression of reproductive toxicity in male rats

This study investigated the capability of a co-delivery system of thymol (THY) and sulfoxaflor that can serve to minimize the development of epididymal and testicular injury arise from SFX exposures alone. Forty-eight adult male rats were orally treated by gavage for 28 consecutive days. The rats were divided into six groups comprising control, THY alone (30 mg/kg), low SFX alone (79.4 mg/kg), high SFX alone (205 mg/kg) and co-exposure groups. After euthanasia, the rats epididymal and testicular damage and antioxidant status markers, myeloperoxidase (MPO) activity, levels of nitric oxide, total antioxidant capacity (TAC), total oxidative stress (TOS) and lipid peroxidation (LPO) were analyzed. Levels of tumor necrosis factor alpha (TNF-α), interleukin-1 b (IL-1β) and caspase-3 activity were assessed using ELISA kits. The results revealed that SFX exposure caused a significant (p < 0.05) decrease in the body weight, sperm functional parameters, serum testosterone level with widespread histological abnormalities in a dose-dependent manner. Increased relative organ weights, serum levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH) were observed in low SFX-treated rats. Similarly, the epididymal and testicular myeloperoxidase activity, malondialdehyde (MDA), reactive oxygen species (RONS), tumor necrosis-α, interleukin-1β levels and caspase-3 activity were significant (p < 0.05) increased and a significant (p < 0.05) reduction in antioxidant enzyme activities and reduced glutathione (GSH) were revealed in SFX-treated rats. However, co-treatment of THY with SFX prevented SFX-induced epididymal and testicular toxicities. Thus, thymol protected against potential epididymis and testes alterations elicited by oxido-inflammatory mediators and up regulated antioxidant status.

An evidence based comprehensive review on thiacloprid, a pesticide residue, induced toxicity: Unveiling hazard to human health

Thiacloprid, a hazardous neonicotinoid insecticide, prevalent in daily agricultural practices, raises concerns due to the harmful effects of its residues on food items, and on unintended organisms poses a significant threat to human health. Introduced in 1990, Thiacloprid have gained popularity for its perceived effectiveness and reduced risks to non-target animals. However, emerging research in recent years reports significant toxic effects of Thiacloprid on non-target species, spanning neurotoxicity, immunotoxicity, hepatotoxicity, nephrotoxicity, and reproductive issues. Mammalian studies, particularly involving rodents, reveal cognitive impairment, hippocampal damage, and hepatic abnormalities upon Thiacloprid exposure. Reproductive toxicity and DNA damage are imminent concerns, disrupting gestational epigenetic reprogramming and suggesting persistent effects on future generations. Genotoxic effects, Embryotoxic, and observed reproductive toxicity accentuate the need for caution in the utilization of Thiacloprid. This review highlights reported toxic effects produced by Thiacloprid in recent years, challenging the initial belief in its lower toxicity for vertebrates.

Associations between neonicotinoid insecticide levels in follicular fluid and serum and reproductive outcomes among women undergoing assisted reproductive technology: An observational study

Neonicotinoid insecticides (NEOs) are a widely used type of insecticide found globally, leading to broad human exposure. However, there is limited research on how internal exposure levels of NEOs and their metabolites impact in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes. A study was conducted at the Sixth Affiliated Hospital of Sun Yat-sen University between 2017 and 2020 involving 436 women undergoing IVF/ICSI treatment. Data on demographics and clinical history were collected from medical records. The concentrations of 11 NEOs and 4 NEO metabolites in follicular fluid and serum were measured using a salting-out assisted liquid-liquid extraction method and liquid chromatography-tandem mass spectrometry. Our findings indicated that NEOs were prevalent in women with infertility. One NEO metabolite, N-dm-ACE, was detected in all samples with median concentrations of 0.221 ng/mL in follicular fluid and 0.228 ng/mL in serum. The study showed a decrease in the number of retrieved oocytes, mature oocytes, 2 PN zygotes, and high-quality embryos as the number of exposed NEOs in follicular fluid increased. Women in the highest tertile of N-dm-ACE exposure had fewer mature oocytes, 2 PN zygotes, and lower oocyte maturity rates compared to those in the lowest tertile. The findings suggest that exposure to NEOs may negatively impact reproductive outcomes in IVF/ICSI pregnancies, particularly affecting oocyte retrieval and embryo quality. This study highlights the potential adverse effects of environmental NEO exposure on IVF/ICSI outcomes, emphasizing the importance of considering such exposures in preconception care.

Increased spontaneous activity and progressive suppression of adult neurogenesis in the hippocampus of rat offspring after maternal exposure to imidacloprid

Imidacloprid (IMI) is a widely used neonicotinoid insecticide that poses risks for developmental neurotoxicity in mammals. The present study investigated the effects of maternal exposure to IMI on behaviors and adult neurogenesis in the hippocampal dentate gyrus (DG) of rat offspring. Dams were exposed to IMI via diet (83, 250, or 750 ppm in diet) from gestational day 6 until day 21 post-delivery on weaning, and offspring were maintained until adulthood on postnatal day 77. In the neurogenic niche, 750-ppm IMI decreased numbers of late-stage neural progenitor cells (NPCs) and post-mitotic immature granule cells by suppressing NPC proliferation and ERK1/2-FOS-mediated synaptic plasticity of granule cells on weaning. Suppressed reelin signaling might be responsible for the observed reductions of neurogenesis and synaptic plasticity. In adulthood, IMI at ≥ 250 ppm decreased neural stem cells by suppressing their proliferation and increasing apoptosis, and mature granule cells were reduced due to suppressed NPC differentiation. Behavioral tests revealed increased spontaneous activity in adulthood at 750 ppm. IMI decreased hippocampal acetylcholinesterase activity and Chrnb2 transcript levels in the DG on weaning and in adulthood. IMI increased numbers of astrocytes and M1-type microglia in the DG hilus, and upregulated neuroinflammation and oxidative stress-related genes on weaning. In adulthood, IMI increased malondialdehyde level and number of M1-type microglia, and downregulated neuroinflammation and oxidative stress-related genes. These results suggest that IMI persistently affected cholinergic signaling, induced neuroinflammation and oxidative stress during exposure, and increased sensitivity to oxidative stress after exposure in the hippocampus, causing hyperactivity and progressive suppression of neurogenesis in adulthood. The no-observed-adverse-effect level of IMI for offspring behaviors and hippocampal neurogenesis was determined to be 83 ppm (5.5-14.1 mg/kg body weight/day).

Thiacloprid impairs reproductive functions of male Wistar rats

Global male infertility correlated to the rise of endocrine-disrupting chemicals, including insecticides, has grown into a pressing problem. Thiacloprid is one of the most commonly used neonicotinoids that accounts for more than 25% of the global pesticide industry. However, its impact on the reproductive system and male fertility has not been fully elucidated. The object of this study was to explore the adverse effects of thiacloprid on male Wistar rats' reproductive system. Thirty healthy male rats were separated into one of three groups: control group, and two groups that were orally administered with low (22.5 mg/kg) and high dose (62.1 mg/kg) of thiacloprid for 56 days. Thiacloprid significantly (p<0.05) reduced body weight and relative testicular weight, as well as sperm quality (count, motility, viability, and morphology), in a dose-dependent manner. THIA-treated groups revealed a large effect (d > 0.8) on semen quality with Cohen's d of (6.57, 8.82), (20.14, 23.54), and (2.81, 9.10) for count, motility, and viability respectively. Meanwhile, the serum testosterone level dropped while the levels of luteinizing and follicle-stimulating hormones increased. 17ꞵ-hydroxy steroid dehydrogenase and 3ꞵ-hydroxy steroid dehydrogenase levels were significantly decreased in a dose-dependent manner. The activity of the tested antioxidant enzymes catalase (CAT), glutathione reduced (GSH), and superoxide dismutase (SOD) exhibited a considerable decrease compared to the control group with a significant elevation in the lipid peroxidation activity as indicated by malondialdehyde (MDA) level. The testicular histology revealed degenerative changes in spermatogenic cells and interstitial tissue. Comet assay revealed DNA fragmentation in treated groups' testicular tissue. Thiacloprid exposure interferes with reproductive function and impairs male Wistar rat fertility. Such harmful consequences may also develop in humans frequently exposed to thiacloprid.

Biofiltering capacity of Chambardia rubens (Bivalvia: Unionidae) may modulate expression of stress and growth genes inhibited by the neonicotinoid insecticide acetamiprid in zebrafish

Neonicotinoid insecticides specifically target insect subtypes of nicotinic acetylcholine receptors. Acetamiprid (ACE: C10H11ClN4), the neonicotinoid insecticide, is used to control crop insect pests worldwide. It is a nitrile, monochloropyridine, and carboxamidine that is highly soluble and accessible to waterways. There, it causes neurotoxic and oxidative perturbance to non-target organisms. The unionid mussel Chamabradia rubens is a common Northern River Nile suspension feeder. The current study aimed to assess ACE filtration from waters by C. rubens, and whether this biological power can reduce ACE effects on fish. Removal of ACE by C. rubens was assessed using LC-MS/MS. Zebrafish Danio rerio adults were exposed to different sublethal doses of ACE in the presence or absence of C. rubens in their aquaria. The results showed that mussels could remove significant ACE amounts from water, where it accumulated mostly in the digestive gland. The presence of C.rubens in zebrafish aquaria having ACE was accompanied by significant upregulation of antioxidant enzyme gene transcripts and total H2O2 scavenging, in contrast to mussel-free ACE-exposed groups. Meanwhile, liver triglycerides rose 5-6-fold in response to ACE in the "Fish-Only" groups, indicating an ACE-induced hepatotoxicity. Also, Insulin-like growth factor 1 (igf1) and fish body mass increased more in "Fish + Mussel" groups than in the "Fish-Only" ones. In aggregate, these findings suggest that the Nile mussel could reduce the oxidative stress and metabolic changes induced in fish by ACE. This can contribute valuable environmental and economic benefits upon the use of this mussel as a biofilter.

The protective role of L-carnitine on oxidative stress, neurotransmitter perturbations, astrogliosis, and apoptosis induced by thiamethoxam in the brains of male rats

Synthetic organic insecticides such as pyrethroids, organophosphates, neonicotinoids, and others have the potential to disrupt ecosystems and are often toxic to humans. Thiamethoxam (TMX), a neonicotinoid insecticide , is a widely used insecticide with neurotoxic potential. L-Carnitine (LC) is regarded as the "gatekeeper" in charge of allowing long-chain fatty acids into cell mitochondria. LC is an endogenous chemical that is renowned for its prospective biological activity in addition to its role in energy metabolism. This study investigated the protective effects of LC against TMX-induced neurotoxicity in male Wistar rats. For 28 days, animals were divided into four groups and treated daily with either LC (300 mg/kg), TMX (100 mg/kg), or both at the aforementioned doses. Our results revealed marked serum lipid profile and electrolyte changes, declines in brain antioxidants and neurotransmitters (acetylcholine, dopamine, and serotonin levels) with elevations in thiobarbituric acid reactive substances and proinflammatory cytokine levels, as well as acetylcholinesterase and monoamine oxidase brain activity in TMX-treated rats. TMX also increased the expression of caspase-3 and glial fibrillary acidic protein. In contrast, pretreatment with LC attenuated TMX-induced brain injury by suppressing oxidative stress and proinflammatory cytokines and modulating neurotransmitter levels. It also ameliorated the expression of apoptotic and astrogliosis markers. It could be concluded that LC has antioxidant, anti-inflammatory, anti-astrogliosis, and anti-apoptotic potential against TMX neurotoxicity.

Mechanistic and predictive studies on the oxidation of furans by cytochrome P450: A DFT study

Furan-containing compounds distribute widely in food, herbal medicines, industrial synthetic products, and environmental media. These compounds can undergo oxidative metabolism catalyzed by cytochrome P450 enzymes (CYP450) within organisms, which may produce reactive products, possibly reacting with biomolecules to induce toxic effects. In this work, we performed DFT calculations to investigate the CYP450-mediated metabolic mechanism of furan-ring oxidation using 2-methylfuran as a model substrate, meanwhile, we studied the regioselective competition of another hydroxylation reaction involving methyl group of 2-methylfuran. As a result, we found the toxicological-relevant cis-enedione product can be produced from O-addition directly via a concerted manner without formation of an epoxide intermediate as traditionally believed. Moreover, our calculations demonstrate the kinetic and thermodynamic feasibility of both furan-ring oxidation and methyl hydroxylation pathways, although the former pathway is a bit more favorable. We then constructed a linear model to predict the rate-limiting activation energies (ΔE*) of O-addition with 11 diverse furan substates based on their adiabatic ionization potentials (AIPs) and condensation Fukui functions (CFFs). The results show a good predictive ability (R2=0.94, Q2CV=0.87). Therefore, AIP and CFF with clear physichem meanings relevant to the mechanism, emerge as pivotal molecular descriptors to enable the fast prediction of furan-ring oxidation reactivities for quick insight into the toxicological risk of furans, using just ground-state calculations.

Dinotefuran exposure alters biochemical, metabolomic, gut microbiome, and growth responses in decapoda pacific white shrimp Penaeus vannamei

Dinotefuran, a neonicotinoid insecticide, may impact nontarget organisms such as Decapoda P. vannamei shrimp with nervous systems similar to insects. Exposing shrimp to low dinotefuran concentrations (6, 60, and 600 μg/L) for 21 days affected growth, hepatosomatic index, and survival. Biomarkers erythromycin-N-demethylase, alanine aminotransferase, and catalase increased in all exposed groups, while glutathione S-transferase is the opposite; aminopyrin-N-demethylase, malondialdehyde, and aspartate aminotransferase increased at 60 and 600 μg/L. Concentration-dependent effects on gut microbiota altered the abundance of bacterial groups, increased potentially pathogenic and oxidative stress-resistant phenotypes, and decreased biofilm formation. Gram-positive/negative microbiota changed significantly. Metabolite differences between the exposed and control groups were identified using mass spectrometry and KEGG pathway enrichment. N-acetylcystathionine showed potential as a reliable dinotefuran metabolic marker. Weighted correlation network analysis (WGCNA) results indicated high connectivity of cruecdysone in the metabolite network and significant enrichment at 600 μg/L dinotefuran. The WGCNA results revealed a highly significant negative correlation between two key metabolites, caldine and indican, and the gut microbiota within co-expression modules. Overall, the risk of dinotefuran exposure to non-target organisms in aquatic environments still requires further attention.

A chromosome-level genome assembly of the soybean pod borer: insights into larval transcriptional response to transgenic soybean expressing the pesticidal Cry1Ac protein

BACKGROUND

Genetically modified (GM) crop plants with transgenic expression of Bacillus thuringiensis (Bt) pesticidal proteins are used to manage feeding damage by pest insects. The durability of this technology is threatened by the selection for resistance in pest populations. The molecular mechanism(s) involved in insect physiological response or evolution of resistance to Bt is not fully understood.

RESULTS

To investigate the response of a susceptible target insect to Bt, the soybean pod borer, Leguminivora glycinivorella (Lepidoptera: Tortricidae), was exposed to soybean, Glycine max, expressing Cry1Ac pesticidal protein or the non-transgenic parental cultivar. Assessment of larval changes in gene expression was facilitated by a third-generation sequenced and scaffolded chromosome-level assembly of the L. glycinivorella genome (657.4 Mb; 27 autosomes + Z chromosome), and subsequent structural annotation of 18,197 RefSeq gene models encoding 23,735 putative mRNA transcripts. Exposure of L. glycinivorella larvae to transgenic Cry1Ac G. max resulted in prediction of significant differential gene expression for 204 gene models (64 up- and 140 down-regulated) and differential splicing among isoforms for 10 genes compared to unexposed cohorts. Differentially expressed genes (DEGs) included putative peritrophic membrane constituents, orthologs of Bt receptor-encoding genes previously linked or associated with Bt resistance, and those involved in stress responses. Putative functional Gene Ontology (GO) annotations assigned to DEGs were significantly enriched for 36 categories at GO level 2, respectively. Most significantly enriched cellular component (CC), biological process (BP), and molecular function (MF) categories corresponded to vacuolar and microbody, transport and metabolic processes, and binding and reductase activities. The DEGs in enriched GO categories were biased for those that were down-regulated (≥ 0.783), with only MF categories GTPase and iron binding activities were bias for up-regulation genes.

CONCLUSIONS

This study provides insights into pathways and processes involved larval response to Bt intoxication, which may inform future unbiased investigations into mechanisms of resistance that show no evidence of alteration in midgut receptors.

Development of Green and Facile Sample Preparation Method for Determination of Seven Neonicotinoids in Fresh Vegetables, and Dissipation and Risk Assessment of Imidacloprid and Dinotefuran

A facile procedure for extracting and determining seven neonicotinoids was developed. Water was the only extraction solvent without phase separation and cleanup steps. The method was validated according to European Union standards, and the values obtained were compared with the criteria. The accuracy values were between 99.8% (thiamethoxam) and 106.8% (clothianidin) at the spiking levels of 0.01, 0.1, and 1 mg/kg in the tested matrices. The precision as pooled RSD values was ≤6.1% (intra-day) and ≤6.9% (inter-day). The limit of quantification was set and tested at 0.01 mg/kg. The matrix effect was evaluated, and all matrices had a suppressive effect. The matrix of the cucumber was the most effective, with -20.9% for dinotefuran and an average of -9.8% for all compounds, while the tomato matrix had the slightest effect. Real marketed samples were analyzed using the developed and QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methods; the results were not significantly different. A supervised field trial was conducted in the open field to study the dissipation patterns of imidacloprid and dinotefuran in tomatoes. The dissipation of both compounds followed first-order kinetics. The half-life (T½) values were 3.4 and 2.5 days, with dissipation rates k of 0.2013 and 0.2781 days, respectively. Following the EU-MRL database, the calculated pre-harvest interval (PHI) values were 7 and 14 days for imidacloprid and dinotefuran, respectively, and 3 days for both compounds following Codex Alimentarius regulations. The risk of imidacloprid and dinotefuran residues was estimated from chronic and acute perspectives. The risk factors of dinotefuran were lower than those of imidacloprid. Nonetheless, the highest expected residues of both compounds were below the tolerance limits.

Pesticide use patterns and their association with cytokine levels in Mexican flower workers

OBJECTIVE

Occupational exposure to pesticides is a known risk for disrupting cellular immune response in flower workers due to their use of multiple chemical products, poor work conditions, and inadequate protection. Recently, the analysis of pesticide use patterns has emerged as an alternative to studying exposure to mixtures of these products. This study aimed to evaluate the association between exposure to different patterns of pesticide use and the cytokine profile of flower workers in the State of Mexico and Morelos, Mexico.

METHODS

A cross-sectional study was carried out on a population of 108 flower workers. Serum levels of IL-4, IL-5, IL-6, IL-8, IL-10 cytokines were analyzed by means of multiplex analysis, and TNF-α and IFN-γ using an ELISA test. Pesticide use patterns were generated by principal components analysis.

RESULTS

The analysis revealed that certain patterns of pesticide use, combining insecticides and fungicides, were associated with higher levels of pro-inflammatory cytokines, particularly IL-6 and IFN-γ.

CONCLUSION

These findings indicate that pesticides may possess immunotoxic properties, contributing to increased inflammatory response. However, further comprehensive epidemiological studies are needed to establish a causal relationship.

Urinary neonicotinoid concentrations and obesity: A cross-sectional study among Chinese adolescents

Epidemiological and toxicological studies on neonicotinoids and obesity have been relevant to adults and young children, but data are limited in adolescents. This study aimed to examine the association between urinary neonicotinoid concentrations and obesity measures among Chinese adolescent. A total of 524 urine samples from 300 boys (11.3-16.1 years) and 224 girls (12.1-15.8 years) were collected to detect the concentrations of eleven neonicotinoids. Generalized linear regression, weighted quantile sum regression (WQS) and Bayesian kernel machine regression (BKMR) were used to estimate covariate-adjusted associations between detectable neonicotinoids and ten indicators of obesity. Nitenpyram concentration was associated with increased body mass index z-score (β = 0.170, 95% CI: 0.041, 0.299) and greater odds of being general obesity (OR = 2.46, 95% CI: 1.11, 5.46). N-desmethyl- acetamiprid concentration was associated with an increase in waist-to-height ratio (β = 0.102, 95% CI: 0.029, 0.176) and waist-to-hip ratio (β = 0.083, 95% CI: 0.011, 0.155). The concentrations of clothianidin (OR = 2.06, 95% CI: 1.10, 3.88) and flonicamid (OR = 2.39, 95% CI: 1.07, 5.32) were associated with greater odds of being abdominal obesity. In contrast, the concentrations of imidacloprid (OR = 0.35, 95% CI: 0.14, 0.88) and thiacloprid (OR = 0.28, 95% CI: 0.08, 0.99) were associated with lower odds of being general obesity. The estimates of general obesity and abdominal obesity increased significantly when concentrations of neonicotinoids mixture were at or above the 55th and 65th percentiles, respectively, compared to the 50th percentile concentration. Sex modified the association between nitenpyram and clothianidin and the risk of obesity with a positive association among boys, and a nonsignificant inverse association among girls. The findings suggest that these associations may be mixed and sex-specific.

Associations between maternal serum neonicotinoid pesticide exposure during pregnancy and newborn telomere length: Effect modification by sampling season

BACKGROUND

An increasing amount of evidence suggests that telomere length (TL) at birth can predict lifespan and is associated with chronic diseases later in life, but newborn TL may be affected by environmental pollutants. Neonicotinoids (NEOs) are widely used worldwide, and despite an increasing number of studies showing that they may have adverse effects on birth in mammals and even humans, few studies have examined the effect of NEO exposure on newborn TLs.

OBJECTIVE

To investigate the effects of prenatal exposure to NEOs and the interactions between NEOs and sampling season on newborn TL.

METHODS

We conducted a prospective cohort study of 500 mother-newborn pairs from the Guangxi Zhuang Birth Cohort. Ultraperformance liquid chromatographymass spectrometry was used to detect ten NEOs in maternal serum, and fluorescence quantitative PCR was used to estimate the newborn TL. A generalized linear model (GLM) was used to evaluate the relationships between individual NEO exposures and TLs , and quantile g-computation (Qgcomp) model and Bayesian kernel machine regression (BKMR) model were used to evaluate the combined effect of mixtures of components.

RESULTS

The results of the GLM showed that compared with maternal TMX levels < LOD, maternal TMX levels < median were negatively correlated with newborn TL (-6.93%, 95% CI%: -11.92%, -1.66%), and the decrease in newborn TL was more pronounced in girls (-9.60%, 95% CI: -16.84%, -1.72%). Moreover, different kinds of maternal NEO exposure had different effects on newborn TL in different sampling seasons, and the effect was statistically significant in all seasons except in autumn. Mixed exposure analysis revealed a potential positive trend between NEOs and newborn TL, but the association was not statistically significant.

CONCLUSION

Prenatal exposure to TMX may shorten newborn TL, and this effect is more pronounced among female newborns. Furthermore, the relationship between NEO exposure and TL may be modified by the sampling season.

Exposure to organophosphate, pyrethroid, and neonicotinoid insecticides and dyslexia: Association with oxidative stress

Organophosphates (OPPs), pyrethroids (PYRs), and neonicotinoids (NNIs) are three major classes of insecticides used worldwide. They might compromise child neurodevelopment. However, few studies have explored the association between exposure to them and dyslexia. The present study aimed to investigate the association between dyslexia and exposure to the three classes of insecticides, as well as explore the potential role of oxidative stress in the association. A total of 355 dyslexic children and 390 controls were included in this study. The exposure biomarkers were determined by liquid chromatography-tandem mass spectrometry. Specifically, the exposure biomarkers included three typical metabolites of OPPs, three of PYRs, and nine of NNIs. Additionally, three typical oxidative stress biomarkers, namely, 8-hydroxy-2'-deoxyguanosine (8-OHdG) for DNA damage, 8-hydroxyguanosine (8-OHG) for RNA damage, and 4-hydroxy-2-nonenal-mercapturic acid (HNEMA) for lipid peroxidation were measured. The detection frequencies of the urinary biomarkers ranged from 83.9% to 100%. Among the target metabolites of the insecticides, a significant association was observed between urinary 3,5,6-trichloro-2-pyridinol (TCPy, the metabolite of chlorpyrifos, an OPP insecticide) and dyslexia. After adjusting for potential confounding variables, children in the highest quartile of TCPy levels had an increased odds of dyslexia (odds ratio [OR], 1.68; 95% confidence interval [CI]: 1.03, 2.75] in comparison to those in the lowest quartile. Among the three oxidative stress biomarkers, urinary HNEMA concentration showed a significant relationship with dyslexia. Children in the highest quartile of HNEMA levels demonstrated an increased dyslexic odds in comparison to those in the lowest quartile after multiple adjustments (OR, 1.64; 95% CI: 1.01, 2.65). Mediation analysis indicated a significant effect of HNEMA in the association between urinary TCPy and dyslexia, with an estimate of 17.2% (P < 0.01). In conclusion, this study suggested the association between urinary TCPy and dyslexia. The association could be attributed to lipid peroxidation partially.

Urinary biomarkers of exposure to organophosphate, pyrethroid, neonicotinoid insecticides and oxidative stress: A repeated measurement analysis among pregnant women

Exposure to insecticides may be associated with increased oxidative stress (OS), but few studies have assessed the associations of OS biomarkers (OSBs) with exposure to multiple insecticides and their mixture, especially in pregnant women who are a vulnerable population. In the present study, 1,094 Chinese pregnant women were recruited and a total of 3,282 urine samples were collected at their three trimesters to measure eight metabolites of organophosphates, three metabolites of pyrethroids, nine typical neonicotinoids/their metabolites, and three OSBs of DNA damage (8-OHdG), RNA damage (8-OHG), and lipid peroxidation (HNE-MA). Among the twenty target insecticide metabolites, sixteen of them were frequently detected; thirteen of them were detected in over 86% of all the urine samples except for imidacloprid (IMI, detection frequency: 72.9%), desnitro-imidacloprid (DN-IMI, 70.0%), and clothianidin (CLO, 79.6%). The reproducibility of their concentrations across the three trimesters was poor to fair (intraclass correlation coefficients <0.50). Multiparity and warm season were related to higher urinary levels of some insecticide metabolites, while higher education level and inadequate weight gain during pregnancy were significantly associated with lower concentrations of certain insecticide metabolites. Linear mixed model analyses suggested that almost all the frequently detected insecticide metabolites [other than 3-phenoxybenzoic acid (3-PBA)] were significantly associated with elevated levels of the three OSBs (8-OHdG, 8-OHG, and HNE-MA), where the percent change (Δ%) ranged 8.10-36.0% for 8-OHdG, 8.49-34.7% for 8-OHG, and 5.92-182% for HNE-MA, respectively, with each interquartile ratio (IQR)-fold increase in the concentrations of the individual exposure biomarkers. Weighted quantile sum models demonstrated that the insecticide metabolite mixture was positively associated with the three OSBs. Overall, urinary desmethyl-clothianidin (DM-CLO) and 3,5,6-trichloro-2-pyridinol (TCPy) were the top insecticide exposure biomarkers contributing to the association with 8-OHdG and 8-OHG levels, while PNP contributed the most to the association with HNE-MA levels. These findings suggested that gestational exposure to organophosphates, pyrethroids, neonicotinoids, their transformation products, and their mixture may increase oxidative damage to lipids, RNA, and DNA during pregnancy.

Maternal serum neonicotinoids during early-mid pregnancy and congenital heart diseases in offspring: An exploratory study

Experimental evidence has indicated a correlation between in-utero exposure to neonicotinoid pesticides (NEOs) and adverse birth outcomes in mammals. However, the distribution of NEO exposure during human pregnancy, as well as its association with congenital heart diseases (CHDs), the most common birth defects, are unclear. Our purpose was to explore the distribution of and contributing factors to NEO exposure in pregnant women during early-mid pregnancy and to assess the associations between NEOs and CHDs. This nested case-control study was conducted within an ongoing prospective birth cohort study and enrolled 141 CHD singletons and their 282 individually matched controls. Six "parent" NEOs and three NEO metabolites were measured in maternal serum collected at an average gestational age of 16 weeks, using liquid chromatography-tandem mass spectrometry. Logistic regression was used to quantify the NEOs-CHDs associations and explore potential contributing factors to serum NEO levels in controls. N-desmethyl acetamiprid (N-dm-ACE) and imidacloprid (IMI) were the most frequently detected NEOs, found in 100% and 20% of maternal sera, respectively. We did not find a statistically significant association between total NEOs and overall CHDs. However, there was a trend towards a higher risk of septal defects with greater serum NEOs (ORs ranged from 1.80 to 2.36), especially nitro-containing NEOs represented by IMI. Pregnant women with lower education had elevated serum total NEOs compared to women with higher education (OR = 48.39, 95% CI: 23.48-99.72). Pregnant women were primarily exposed to N-dm-ACE and IMI during early-mid pregnancy. Gestational exposure to NEOs may be associated with an increased risk of septal defects, but the evidence is limited at present. Education is a potential contributing factor to NEO exposure in pregnant women. Larger and more precise studies with longitudinal biospecimen collection, are recommended to validate our exploratory findings.

Physiological response of thiamethoxam and ulexite in rainbow trout: A neural network-mediated approach

Fish, which are in constant contact with water, serve as an important ecological indicator of aquatic environment health. Therefore, in this study, in the name of neural degeneration, thiamethoxam (TMX) insecticide in the cerebral tissue of Oncorhynchus mykiss; neurotoxic endpoints such as biomarkers of oxidative stress, DNA damage and the status of antioxidant enzymes have been identified. Antioxidant enzyme (CAT, SOD, GPx, GSH) activities were significantly inhibited by TMX administration, and MDA and MPO values increased as a result of the stimulation of ROS (p < 0.05). It was interpreted that ulexite (UX) added to the medium was effective in favor of antioxidants and tried to prevent MDA and MPO levels. It was determined that Nrf-2, one of the inflammation parameters, was inhibited as a result of TMX application, and the supplementation of UX to the medium created merits similar to the no treatment group. In the 48th and 96th hour analyses of cerebral tissue, it was determined that IL-6 and TNF-α values were induced in TMX applied groups and UX tried to inhibit this situation. It was commented that TMX induced DNA damage and apoptosis at 48th-96th h, whereas UX suppressed this situation. The results provide possible in vivo evidence that UX supplements can reduce TMX-mediated oxidative stress and brain damage in O. mykiss brain tissue.

Behavioral and physiological changes in the passerine Agelaioides badius following the ingestion of coated seeds with imidacloprid in a 30-day experiment

The wide use of neonicotinoid seed treatment represents a hazard for farmland birds that feed on treated seeds. This study aimed to characterize the long-term effects of the neonicotinoid imidacloprid (IMI) in the passerine grayish baywing (Agelaioides badius). The birds were fed ad libitum for 32 days only with seeds treated with 53.1 (Low, 11 % of LD50) and 514 (High, (112 % of LD50) mg IMI/kg seed; these concentrations representing respectively, 1.8 and 17.1 % of 3 g IMI/kg, an average application rate used to treat crop seeds in Argentina. The effects exerted by IMI on birds were evaluated at behavioral, physiological, hematological, genotoxic, and biochemical levels. No differences in food consumption were observed between Control and Low treatments birds, indicating a lack of aversion to treated seeds. High treatment birds only decreased their food consumption by 20 % in the first 3 days of exposure. Birds from High treatment experienced an early loss of body weight, reduction in their mobility, lack of response to threats (i.e., predator call and approaching person), and altered their use of the cage. On the contrary, birds from Low treatment experienced a delay in the onset of effects like reduction in mobility, lack of response to threats, and a tendency to reduce their body weight. At the end of exposure, glutathione S transferase activity in the plasma of treated birds decreased, and cholinesterase activity increased in the liver of treated birds. This study highlights that consumption equivalent to 1.8 % of the daily diet of baywings as IMI-treated seeds, is sufficient to generate behavioral and physiological alterations and death. In the wild, these effects may have ecological consequences, by impairing the survival of birds, representing a risk to farmland bird populations.

Exploratory analysis of the associations between neonicotinoids insecticides and serum lipid profiles among US adults: A cross-sectional, population-based study

Neonicotinoid insecticides (NNIs) are widely used in agriculture, horticulture, forestry, and household environment, but their potential impact on human health remains a subject of concern. This study aimed to investigate the relationship between NNIs and their metabolites in urine with serum lipid profiles in adults using data from the National Health and Nutrition Examination Survey (NHANES) 2015-2016. The study included 1192 participants aged over 20 years with urinary NNIs levels, serum lipid parameter levels and potential confounders. Urinary concentrations of NNIs, including imidacloprid, acetamiprid, clothianidin, thiacloprid, N-desmethyl-acetamiprid, and 5-hydroxy-imidacloprid, were quantified. Serum lipids profiles, such as total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (Apo-B), were assessed. Considering the effects of lipid-lowering medications, the censored normal regression model was used to explore the associations between urinary NNIs and TC, TG, HDL-C, LDL-C and Apo-B levels. The results revealed a significant increase of 9.0 mg/dL (95%CI: 2.0, 16.1) in TC levels among participants with detectable N-desmethyl-acetamiprid compared to those with undetectable levels. Stratified analysis indicated that the association between N-desmethyl-acetamiprid and HDL-C levels was more pronounced among participants aged ≥ 46 years compared to those aged between 20 and 45 years with undetectable N-desmethyl-acetamiprid (pinteraction=0.044). Additionally, there were marginal effect modification of BMI on the association between N-desmethyl-acetamiprid and LDL-C (pinteraction=0.097) and Apo-B (pinteraction=0.052) levels. Specifically, participants with BMI ≥ 25 kg/m² and detectable N-desmethyl-acetamiprid tended to have higher LDL-C and Apo-B levels compared to those with BMI < 25 kg/m² and undetectable N-desmethyl-acetamiprid. However, no significant associations were observed between other NNIs and lipid profiles in the present study. To validate these findings, further longitudinal studies with larger sample sizes should be conducted, particularly within populations characterized by a high detection rate of NNIs.

Risk assessment of honeybee larvae exposure to pyrethroid insecticides in beebread and honey

Honeybee is an essential pollinator to crops, evaluation to the risk assessment of honeybee larvae exposure to pesticides residue in the bee bread and honey is an important strategy to protect the bee colony due to the mixture of these two matrices is main food for 3-day-old honeybee larvae. In this study, a continuous survey to the residue of five pyrethroid insecticides in bee bread and honey between 2018 and 2020 from 17 major cultivation provinces which can be determined as Northeast, Northwest, Eastern, Central, Southwest, and Southern of China, there was at least one type II pyrethroid insecticide was detected in 54.7 % of the bee bread samples and 43.4 % of the honey. Then, we assayed the acute toxicity of type II pyrethroid insecticides based on the detection results, the LD50 value was 0.2201 μg/larva (beta-cyhalothrin), 0.4507 μg/larva (bifenthrin), 2.0840 μg/larva (fenvalerate), 0.0530 μg/larva (deltamethrin), and 0.1640 μg/larva (beta-cypermethrin), respectively. Finally, the hazard quotient was calculated as larval oral ranged from 0.046 × 10-3 to 2.128 × 10-3. Together, these empirical findings provide further insight into the accurate contamination of honey bee colonies caused by chemical pesticides, which can be used as a valuable guidance for the beekeeping industry and pesticide regulation.

High urinary oxidative DNA damage in wild chimpanzees ranging in proximity of agricultural fields in Sebitoli area, Uganda

Agriculture expansion is a major cause of habitat loss and exposure to phytochemical pollution for non-human primates. In addition to endocrine disruption, exposure to pesticides may have other sublethal physiological consequences for animals, such as generation of oxidative damage to macromolecules. In this study, we analyzed the pesticides contained in the river water across the home range of wild chimpanzees (Pan troglodytes) in Sebitoli area located on the Northern part of Kibale National Park (Uganda). We tested whether levels of three urinary markers of oxidative damage vary among individuals in relation to their ranging patterns, as a proxy for pesticide exposure intensity. To better characterize the foraging habitat use, the trophic level, and the energetic status of study individuals, we also quantified urinary levels of carbon and nitrogen stable isotope signatures and of C-peptide. Among the 511 pesticides screened, 18 compounds including herbicides, insecticides, and fungicides were found in the water sampled in the Western part of the home range of chimpanzees. In this area, chimpanzees used to feed on maize crops. By contrast, in the Eastern part where crop feeding was never observed, we found only seven pesticides. According to their ranging patterns and thus crop feeding frequency, the 139 urine samples collected from 43 Sebitoli chimpanzees were categorized as belonging to low, medium, and high exposure level. Chimpanzees from the high exposure zone had higher oxidative DNA damage (8-OHdG) than chimpanzees from both the low and medium exposure groups, who had similar levels of oxidative DNA damage. In addition, individuals with higher C-peptide tended to have significantly higher oxidative DNA damage and lipid peroxides. The three exposure groups had similar levels of urinary 8-isoprostanes and of urinary lipid peroxides. These results were robust for any potential confounding effect of other variables because neither age category nor sex or isotope levels were significantly associated with markers of oxidative damage. Our study points to genotoxic effects as one potential sublethal consequence of ranging in proximity of agricultural fields owing to exposure to pesticides or other unidentified sources of stress. Given our phylogenetic proximity, this information is relevant for the conservation of this species which is endangered and also sentinel for human health.

Unicellular cyanobacteria degrade sulfoxaflor to its amide metabolite of potentially higher aquatic toxicity

Sulfoxaflor (SFX) is a fourth-generation neonicotinoid used widely in modern agriculture. Due to its high water solubility and mobility in environment, it is expected to occur in water environment. Degradation of SFX leads to formation of corresponding amide (M474), which in the light of recent studies may be much more toxic to aquatic organisms than the parent molecule. Therefore, the aim of the study was to assess the potential of two common species of unicellular bloom-forming cyanobacteria (Synechocystis salina and Microcystis aeruginosa) to metabolize SFX in a 14-day-long experiment, using elevated (10 mg L-1) and predicted highest environmental (10 μg L-1) concentrations. The results obtained support the occurrence of SFX metabolism in cyanobacterial monocultures, leading to release of M474 into the water. Differential SFX decline in culture media, followed by the presence of M474, was observed for both species at different concentration levels. For S. salina, SFX concentration decreased by 7.6% at lower concentration and by 21.3% at higher concentration; the M474 concentrations were 436 ng L-1 and 514 μg L-1, respectively. Corresponding values for M. aeruginosa were 14.3% and 3.0% for SFX decline; 282 ng L-1 and 317 μg L-1 for M474 concentration. In the same time, abiotic degradation was almost non-existent. Metabolic fate of SFX was then studied for its elevated starting concentration. Uptake of SFX to cells and amounts of M474 released to water fully addressed the decrease in SFX concentration in M. aeruginosa culture, while in S. salina 15.5% of initial SFX was transformed to yet unknown metabolites. The degradation rate of SFX observed in the present study is sufficient to produce a concentration of M474 that is potentially toxic for aquatic invertebrates during cyanobacterial blooms. Therefore, there is a need for more reliable risk assessment for the presence of SFX in natural waters.

Multiple pesticide residues and risk assessment of Dendrobium officinale Kimura et Migo: a three-year investigation

Dendrobium officinale Kimura et Migo (D. officinale) is a traditional Chinese medicine homologous to food, and its safety has attracted considerable attention. Pesticide residues are critical indicators for evaluating the safety of D. officinale. This study investigated the levels of 130 pesticides in 137 stem samples and 82 leaf samples from five main production areas of D. officinale in Zhejiang Province, along with the associated risk of dietary exposure for the population between 2019 and 2021. Forty-five pesticides were detected in 171 samples, of which pyraclostrobin had the highest detection frequency. Multiple residues were detected in 52.56% of the stem samples and 54.88% of the leaf samples, and one stem sample contained up to 18 pesticides. Here, the level of difenoconazole in three samples (two stem samples and one leaf sample) was higher than the maximum residue limit (MRL) in China. Considering the possible health risks related to pesticide residues, a risk assessment of human exposure to pesticides via the intake of D. officinale stems and leaves was evaluated, indicating negligible short-term, long-term, and cumulative risks to human health. However, considering the high detection rate of unregistered pesticides, the supplementation of pesticide registration information on D. officinale should be expedited, and MRLs should be established to ensure food and drug safety.