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The use of pesticides is often regarded as a fundamental aspect of conventional agriculture. However, these compounds have gained recognition as some of the oldest and most widely employed xenobiotic contaminants, necessitating effective strategies for human biomonitoring. In this context, a method was developed for the determination of 16 legacy organochlorine pesticides, 6 metabolites of current pesticides (2,4-D, malathion, parathion, fipronil, pyraclostrobin, cypermethrin, permethrin, cyfluthrin), and 1 triazine herbicide (atrazine) in serum. Samples were prepared with water, formic acid, acetonitrile, and ultrasound irradiation, followed by solid-phase extraction with Oasis Prime HLB. Subsequently, metabolites from current pesticides underwent derivatization using MTBSTFA with 1% TBDMSCl for analysis via gas chromatography-tandem mass spectrometry (GC–MS/MS), employing an SLB-5MS fused silica capillary column. Analytical curves were generated with limits of quantification from 0.3 to 4.0 ng.mL−1. Accuracy ranged from 69 to 124%, and the coefficient of variation from 2 to 28%. Moreover, determining 1-(4-chlorophenyl)-1H-pyrazol-3-ol was suggested as a biomarker for pyraclostrobin biomonitoring. This analytical approach facilitated the determination of both legacy and metabolites of current pesticides in the same serum sample, presenting an interesting and cost-effective option for large cohorts, and multi-omics studies that evaluate time-dependent biomarkers in blood samples, thereby enabling biomonitoring within the same matrix. Furthermore, a proof-of-concept involving 10 volunteers demonstrated exposure to 9 pesticides at mean concentrations measured in ng mL−1, consistent with findings from various biomonitoring initiatives. [ABSTRACT FROM AUTHOR]

Food contaminates, such as insecticide, may influence the toxicity of nanoparticles (NPs) to intestine. The present study investigated the combined toxicity of TiO2 NPs and fipronil to male mouse intestine. Juvenile mice (8 weeks) were orally exposed to 5.74 mg/kg TiO2 NPs, 2.5 mg/kg fipronil, or both, once a day, for 5 days. We found that both TiO2 NPs and fipronil induced some pathological changes in intestines, accompanying with defective autophagy, but these effects were not obviously enhanced after TiO2 NP and fipronil co‐exposure. Fipronil promoted Ti accumulation but induced minimal impact on other trace elements in TiO2 NP‐exposed intestines. Metabolomics data revealed that the exposure altered metabolite profiles in mouse intestines, and two KEGG pathways, namely, ascorbate and aldarate metabolism (mmu00053) and glutathione metabolism (mmu00480), were only statistically significantly changed after TiO2 NP and fipronil co‐exposure. Five metabolites, including 2‐deoxy‐D‐erythro‐pentofuranose 5‐phosphate, 5alpha‐cholestanol, beta‐D‐glucopyranuronic acid, elaidic acid, and isopentadecanoic acid, and maltotriose, were more significantly up‐regulated after the co‐exposure, whereas trisaccharide and xylonolactone were only significantly down‐regulated by the co‐exposure. We concluded that fipronil had minimal impact to enhance the toxicity of TiO2 NPs to mouse intestines but altered metabolite profiles. This study investigated the combined toxicity of TiO2 NPs and fipronil to male mouse intestines after repeated oral exposure. We found that TiO2 NPs and fipronil induced pathological changes and defective autophagy, but there were no obvious synergistic effects. Metabolomics data revealed that some KEGG pathways and metabolites were more significantly altered after the co‐exposure compared with single exposure. We concluded that fipronil had minimal impact to enhance the toxicity of TiO2 NPs to mouse intestines but altered metabolite profiles. [ABSTRACT FROM AUTHOR]

Bees play a crucial role in pollination but are exposed to various pesticides during nectar and pollen collection, which can impact their health and pollination efficiency. This study aimed to investigate morphological and histochemical changes in the hypopharyngeal glands of Scaptotrigona postica after exposure to three chemical compounds: glyphosate, fipronil, and Tween. Nurse bees of S. postica were divided into four experimental groups and fed with sucrose syrup containing the compounds for 24 h. After the exposure period, the hypopharyngeal glands were analyzed for morphology using light microscopy and transmission electron microscopy. The hypopharyngeal glands of S. postica exhibited a tubuloacinar structure, with unicellular acini approximately 54 µm in diameter. Exposure to fipronil resulted in changes in the organization of the rough endoplasmic reticulum (RER) and increased area and sphericity of the acini compared to all other groups, as well as a higher presence of proteins in the cytoplasm compared to other pesticides, potentially due to increased food consumption. Bees exposed to glyphosate showed alterations in the mitochondria compared to all groups. The Tween group did not exhibit significant changes in cellular ultrastructure, only a smaller area and sphericity compared to the control group. The hypopharyngeal glands are highly sensitive to pesticides and are efficient bioindicators. Significant changes in these glands can compromise the maintenance of the colony. [ABSTRACT FROM AUTHOR]

Populations of various economic species of wireworms are increasing in the key cereal crop production areas of Canada and the United States. To address this problem, seed treatments are under development that both provide crop protection and significantly reduce populations equivalent in effectiveness to the formerly used but now deregistered organochlorine lindane. Herein, we evaluated isocycloseram (PLINAZOLIN technology), the first isoxazoline (GABA-gated Chloride Channel Allosteric Modulator) agricultural insecticide, as a seed treatment for the protection of cereal crops from the sugarbeet wireworm, Limonius californicus (Mannerheim). In wheat and barley field trials conducted over 4 years under extreme wireworm pressure, isocycloseram applied as a seed treatment at 5.0–7.5 g AI/100 kg seed was as effective as or more effective than the current industry standard thiamethoxam at 20.0 g AI/100 kg seed in protecting crop stand and yield. Isocycloseram also reduced neonate wireworms (produced from eggs during the growing season) and resident wireworms (in the field at the time of planting) to levels expected from the formerly used seed treatment lindane. [ABSTRACT FROM AUTHOR]

The use of nonrepellent liquid termiticides against subterranean termites has long relied on the assumption that foraging termites in soils could transfer toxicants to nestmates to achieve population control. However, their dose-dependent lethal time can lead to rapid termite mortality in proximity of the treatment, triggering secondary repellency. The current study characterizes the dynamic nature of the "death zone," i.e. the area adjacent to soil termiticides that termites would avoid owing the accumulation of cadavers. Using whole subterranean termite laboratory colonies of Coptotermes gestroi (Wasmann) with 3 × 15 m foraging distances, fipronil was implemented at 1.5 m, 7.5 m, or 12.5 m away from colony central nests, emulating a corrective action against an termite structural infestation. For treatments at 7.5 m and 12.5 m, the death zone stabilized at an average of ~2.56 m away from the treatment after 40 d post-treatment, and colonies suffered as little as 1.5% mortality by 200 d post-treatment. Colonies located 1.5 m away from the treatment minimized the death zone to ~1.1 m and suffered as little as 23.5% mortality. Mortality only occurred within the first few days of treatment from initial exposure, as the rapid emergence of the death zone negated further transfer effects among nestmates over time. In some cases, foraging termites were trapped within the infested structure. While technically nonrepellent, fipronil becomes functionally repellent from the rapid mortality onset near the treatment. Even if diligently implemented to successfully protect structures, surrounding termite colonies are minimally impacted by fipronil soil treatments. [ABSTRACT FROM AUTHOR]

BACKGROUND: Horizontal insecticide transfer is thought to play an important role in controlling a wide range of urban pests including ants, bed bugs, cockroaches and termites. Trap–treat–release is an effective experimental approach that has been used to successfully manage populations of invasive ants in field applications. Trap–treat–release is based on the principles of horizontal transfer. Individuals are captured, treated with the toxicant and released back into the environment. The treated individuals then return to the colony and transfer the toxicant to other members of the population resulting in secondary mortality. The goal of the current study was to evaluate the efficacy of the trap–treat–release technique for controlling field populations of the eastern yellowjacket, Vespula maculifrons. RESULTS: Laboratory experiments demonstrated that fipronil was highly toxic against V. maculifrons across a wide range of concentrations. Furthermore, fipronil was efficiently transferred from treated donors to untreated recipients and caused significant secondary mortality. A field experiment utilized trap–treat–release and demonstrated that fipronil was effectively transferred when foraging worker wasps are trapped, treated, released and allowed to return to their respective colonies. CONCLUSION: The trap–treat–release method may be an effective alternative to direct nest treatments and could help alleviate problems such as insecticide runoff, environmental contamination, and non‐target effects. This method has the potential to provide effective management of social wasps. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Herein, we report a large-scale solid-state synthesis method for water-soluble graphitic carbon nitride nanoparticles (g-CNNPs) using urea and trisodium citrate, adhering to the principle of atom economy. The as-synthesized g-CNNPs, approximately 3.0 nm in size with a quasi-spherical structure and having a high water-soluble property, exhibit strong blue fluorescence emission. The surface of g-CNNPs contains six surface active sites and serves as an effective fluorescence sensor for the detection of the insecticide fipronil (FPN) at pH 7.0. The size variation of g-CNNPs (2–4.5 nm) induces size-dependent surface effects, contributing to their upconversion properties. The quasi-spherical g-CNNPs (ΦF 21.08%) demonstrate high selectivity and sensitivity for FPN detection, with a limit of detection (LoD) of 2.79 nM (R2 = 0.99511) and a limit of quantification (LoQ) of 9.30 nM within a linear concentration range of 1 × 104 to 9 × 104 nM (ΦF 17.40%), and an association constant (Ka) of 1.356 × 102 M–1. The observed fluorescence quenching during the sensitivity study is likely due to intermolecular hydrogen bonding between g-CNNPs and FPN. Time-correlated single photon counting (TCSPC) analysis confirms the static quenching of g-CNNPs (lifetime 5.53–5.60 ns) upon FPN detection. To confirm the pH-dependent behavior of g-CNNPs and FPN interaction, the TCSPC technique was carried out in particular at pH 3.0 and 11. Density functional theory studies were conducted to confirm the interaction between g-CNNPs and FPN molecules. Additionally, the g-CNNPs demonstrated practical applicability by detecting FPN in soil samples with recovery rates ranging from 102.5 to 129.7%. Due to their low cytotoxicity and good cell permeability, g-CNNPs were successfully applied for selective cytotoxic effects and bioimaging in zebrafish. [ABSTRACT FROM AUTHOR]

Phenylpyrazoles are widely used pesticides in the food industry. It is highly desirable to develop efficient pre‐treatment and analysis methods to extract and detect phenylpyrazoles in complex food matrices. Herein, the study reports novel squaraine‐linked zwitterionic core‐shell magnetic covalent organic frameworks (MCOFs),  which are found to be excellent pretreatment materials for the detection of trace phenylpyrazoles in samples. By coupling MCOFs to magnetic solid‐phase extraction (MSPE) with Ultra Performance Liquid Chromatography‐Tandem Mass Spectrometry (UPLC‐MS/MS) analysis, the detection of phenylpyrazoles (fipronil, fipronil sulfone, fipronil sulfide, fipronil de‐sulfoxide, fipronil desulfinyl, ethiprole, and flufiprole) is achieved and shows good linearity at concentrations of 1–800 µg L−1 (R2 ≥ 0.9930). The limit of detection (LOD), limit of quantification (LOQ), and recovery rates are 0.01–0.50 µg kg−1, 0.04‐1.72 µg kg−1, and 70.96–115.32%, respectively. More importantly, this method is successfully applied to determine the phenylpyrazoles in commercial egg, poultry, milk, jujube, cabbage, tea, and rice with a detection rate of ≈0.04%. Therefore, the developed method may contribute to a new strategy for the purification and multi‐target extraction of complex food matrices. [ABSTRACT FROM AUTHOR]

Development of acaricide resistance in tick population is a major concern in livestock as well as in pet animals. Reduced responsiveness has been observed against commonly used acaricides in Rhipicephalus sanguineus tick infested dogs in the Agartala city of North-eastern part of India. Two acaricides Deltamethrin and Fipronil were chosen for acaricidal resistance study using Adult Immersion Test (AIT) and Larval Packet Test (LPT). AIT study revealed the lowest and highest mortality of adult ticks at 25 ppm and 200 ppm concentration of Deltamethrin, respectively. Similarly for fipnonil, lowest and highest mortality was recorded at 25 ppm and 100 ppm, respectively. With increasing the concentration of both deltamethrin and fipronil, the reproductive index of ticks was found to be decreased with increased inhibition of oviposition. In LPT study, lowest mortality of R. sanguineus larvae was recorded at 25 ppm of deltamethrin and highest mortality at 200 ppm. For fipronil, lowest and highest mortality was recorded at 25 ppm and at 100 ppm, respectively. The study revealed that both the acaricides produced lower mortality of ticks at their market recommended doses. However, fipronil was found to be more effective than that of deltamethrin. The observed resistance warrants immediate measures to prevent further development of acaricide resistance in tick population in dogs in the study area. [ABSTRACT FROM AUTHOR]

The purpose of the research is to study the acute oral and dermal toxicity of a veterinary drug (fipronil, pyriproxyfen) in mice and rats.Materials and methods. The studies were performed according to the Methodical Guidelines of the State Pharmacological Committee in the vivarium of the VNIIP – FSC VIEV from February to April 2021. White outbred male mice and male rats were used as a test system to study toxicological characteristics of the study drug. The veterinary drug Insektal Shampoo is a topical solution that contains fipronil and pyriproxyfen as active ingredients. In studying the acute oral toxicity and acute dermal toxicity of the study drug on laboratory animals, established procedures were used.Results and discussion. The median lethal dose (LD50) was 12 500 (11,532÷13,468) mg/kg when administered to the white male mice intragastrically as per Miller-Tainter method. According to the generally accepted hygiene classification, the drug was classified as hazard class 4 according to GOST 12.1.007-76. For the white male rats, LD50 was more than 20,800 mg/ kg (hazard class 4). When applied to intact rat skin, LD50 was more than 10 400 mg/kg, which corresponds to hazard class 4.

Ethiprole (ETH) is a phenylpyrazole insecticide that is used worldwide as an alternative to fipronil (FIP). Research on the photodegradation of ETH in aquatic environments has been limited compared with that on FIP. In this study, to clarify the photodegradation of ETH in aquatic systems, the photodegradation pathway and products were investigated using liquid chromatography and liquid chromatography-tandem mass spectrometry. We also determined the photochemical half-lives (t1/2) of ETH and its main degradation products. The primary photodegradation pathway was cyclization/dechlorination and hydroxylation/dechlorination of ETH to form the didechlorinated products (benzimidazole of des-chloro-hydroxy-ETH). Some newly identified photodegradation products and analogs of FIP photodegradation products were also detected as minor products. We compared the photodegradation of ETH with that of FIP under the same conditions. Didechlorinated products of ETH and FIP had the highest photostability. However, although the photochemical t1/2 of EHT was 2.7 times that of FIP, the photochemical t1/2 of the didechlorinated product of ETH was approximately one-third that of the didechlorinated product of FIP. This comparison of the photochemical processes of ETH and FIP provides new insight into the persistence and characteristics of both insecticides in the environment. [ABSTRACT FROM AUTHOR]

The so-called EPT taxa have been shown to be highly sensitive to various environmental pollutants. However, there are only few published studies on toxicity testing with EPT representatives and there is a particular lack of protocols for chronic toxicity testing, e.g., for integration into species sensitivity distribution (SSD) approaches. To address this gap, we performed a long-term 38-day semi-static toxicity test with the European mayfly species Cloeon dipterum using the insecticide fipronil as model substance. The functionality of the test system was confirmed by the high emergence rate of 85% in the control condition. We found a high sensitivity with regard to larval development with an EC50 of 180 ng/L and a NOEC of 38.0 ng/L after 7 days exposure. After 38 days, an LC50 value of 185 ng/L and an EC50 value of 160 ng/L for emergence (both: NOEC = 38.0 ng/L) were calculated. In a short-term 7-day toxicity test, we found a similar effect on larval development. In addition to the physiological endpoints, we examined fipronil-induced gene expression changes at the transcriptome level in this test. Our results revealed a concentration-dependent increase in the number of differentially expressed genes, as well as observed effects on larval development. Notably, we identified marker gene candidates involved in nervous system development, mirroring the known mode-of-action of fipronil in C. dipterum. The affected genes primarily play crucial roles in neurological processes. Concluding, within this two-step approach we were able to identify fipronil effects on the sublethal physiological endpoint larval development and to complement these effects at the molecular level by gene expression changes in the transcriptome. Thus, this assay proved to be suitable to assess sublethal effects as well as the mode-of-action of substances in the non-standard organism C. dipterum already after a short-term exposure of 7 days. However, further testing is required to validate the procedure. [ABSTRACT FROM AUTHOR]

Taking into consideration that bees can be contaminated by pesticides through the ingestion of contaminated floral resources, we can utilize genetic techniques to assess effects that are scarcely observed in behavioral studies. This study aimed to investigate the genetic effects of ingesting lethal and sublethal doses of the insecticide fipronil in foraging honey bees during two periods of acute exposure. Bees were exposed to fipronil through contaminated honey syrup at two dosages (LD50 = 0.19 µg/bee; LD50/100 = 0.0019 µg/bee) and for two durations (1 and 4 h). Following exposure, we measured syrup consumption per bee, analyzed the transcriptome of bee brain tissue, and identified differentially expressed genes (DEGs), categorizing them functionally based on gene ontology (GO). The results revealed a significant genetic response in honey bees after exposure to fipronil, regardless of the dosage used. Fipronil affected various metabolic, transport, and cellular regulation pathways, as well as detoxification processes and xenobiotic substance detection. Additionally, the downregulation of several DEGs belonging to the olfactory-binding protein (OBP) family was observed, suggesting potential physiological alterations in bees that may lead to disoriented behaviors and reduced foraging efficiency. [ABSTRACT FROM AUTHOR]

Retention and degradation of co-applied atrazine and fipronil was studied in laboratory constructed bio-augmented biobeds containing rice straw-compost (BM) and compost replaced with 10% rice husk ash [RHABM(10%)] or 1% wheat straw biochar [WBCBM(1%)] biomixtures. Atrazine (5000 µg, 50% WP) and fipronil (5000 µg, 0.3 G) were co-applied in 100 mL water. After 30 days, 7.31, 4.65, and 11.21 µg g−1 atrazine and 21.59, 7.41, and 37.20 µg g−1 fipronil remained undegraded in the top 3–4 cm of BM, RHABM(10%), WBCBM(1%) biobeds, respectively, suggesting that degradation of both pesticides significantly varied (p < 0.05) among the three biobeds. After 60 days 94.5%–98.3% of initially applied atrazine and 80.3%–86.9% fipronil degradation was observed. Hydroxyatrazine and sulphone were detected as the metabolites of atrazine and fipronil, respectively. Out of 5000 µg of initially applied pesticides, BM, RHABM(10%), and WBCBM(1%) biobeds accounted for 95.2%, 93.1%, and 95.2% of atrazine + hydroxyatrazine and 62.8%, 67.0%, and 71.5% of fipronil + sulphone degradation, respectively. Maximum amounts of recovered atrazine (68.8%–81.1%) and fipronil (89.8%–94.6%) were retained in the 0–5 cm sections of the biobeds. No significant effect of co-applied atrazine + fipronil was evident on the microbial parameters. This study suggested that RHA/WBC-mixed rice straw-compost biomixtures can be exploited for the detoxification of these pesticides in bio-purification systems. [ABSTRACT FROM AUTHOR]

The western drywood termite, Incisitermes minor (Hagen), causes significant economic damage to wood structures in the United States of America, especially California. When infestation is not widespread, localized insecticide injections may be useful for remedial control. However, the extensive gallery structure of drywood termites and their tendency to aggregate at specific parts of the galleries can impact the efficacy of localized insecticide injection. Chemicals that attract termites from a distance may improve the localized insecticide injection by increasing the number of termites contacting the insecticide residues. Two volatile terpenes, α-pinene and β-pinene, commonly found in many coniferous timber trees, were applied to artificial termite galleries to determine if termites were attracted from their original aggregation site. Furthermore, we examined if adding these pinenes would improve the overall efficacy of some insecticide products for drywood termite control. Behavioral assay results showed that the treatment with pinenes increased the likelihood that drywood termites would leave their original aggregation site and contact the treated part of the gallery. When tested with the pesticide products applied in a small area away from the termite aggregation, β-pinene significantly accelerated the time course of mortality for the aqueous fipronil. The efficacy of disodium octaborate tetrahydrate dust was not influenced by the addition of pinenes. Implications for drywood termite management and future research directions are discussed. [ABSTRACT FROM AUTHOR]

Subterranean termites cause significant damage to agricultural crops and wooden infrastructures worldwide. Coptotermes and Odontotermes were found as the most abundant and damaging genera of subterranean termites in Pakistan. Many conventional synthetic insecticides are being used to combat termite infestations with often unsatisfactory control results. This study assessed the comparative toxicity of some prevailing synthetic insecticides with different modes of action against subterranean termites Coptotermes heimi Wasmann (Isoptera: Rhinotermitidae) which was found as a dominant termite species in district Sargodha. Filter paper disc-based bioassays revealed that all insecticides showed a significant impact (P < 0.001) on the mortality of C. heimi workers and this mortality response was directly proportional to insecticidal concentrations and exposure times. Significantly higher mortality was recorded by chlorpyrifos (100.0%) and fipronil (95.0%) at 72 h post-exposure with minimum LC50 values of 1.29 and 2.04%, respectively. Similar trend of effectiveness was exhibited by their LT50 values. Minimum mortality of C. heimi workers was recorded by the formulations of chlorantraniliprole and abamectin. Based on overall study results, it is concluded that chlorpyrifos and fipronil are effective synthetic termiticides and are recommended to the indigenous farmers for combatting subterranean termite infestations. [ABSTRACT FROM AUTHOR]

Parasitic skin diseases are important part of feline dermatology in general. Feline demodicosis is caused by Demodex cati, Demodex gatoi and an unnamed species. The present investigation was conducted to diagnose and study the haemato-biochemical alterations and therapeutic efficacy of ivermectin and eprinomectin with Fipronil in feline demodicosis. Clinical examinations of gross lesions and microscopic examination of deep skin scrapings were used for diagnosis. Haematological study revealed microcytic hypochromic anaemia, leucocytosis with neutrophilia, lymphopenia and eosinophilia in most of cats with demodicosis which improved significantly following 28 days of treatment. No significant change in plasma AST-ALT activity was noted in cats affected with demodicosis. The efficacy of different therapeutic regimens was assessed based on disappearance of clinical symptoms and restoration of altered haematobiochemical parameters. It was found that both the regimen were effective for treatment of demodectic cats, however, the recovery rate was faster in group treated with spot on containing two acaricide drug eprinomectin and fipronil. [ABSTRACT FROM AUTHOR]

Simple Summary: Small hive beetles (Aethina tumida) are a honey bee pest with few reliable in-hive chemical treatments available for beekeepers to use in the United States. Gel roach baits have been used off-label by commercial beekeepers as an alternative way to reduce small hive beetle populations. The objective of this study was to determine the toxicity of the active ingredients in gel roach baits to small hive beetles and honey bees (Apis mellifera) through topical exposure. In addition, we exposed small hive beetles to the active ingredients orally through pollen. All the active ingredients tested were more toxic to honey bees than to small hive beetles, except for fipronil, which was only slightly less toxic to honey bees than small hive beetles. The results of this study imply that gel roach baits should not be used in honey bee hives as small hive beetle treatments due to their toxicity to honey bees. Beekeepers need new treatment options for controlling small hive beetles (Aethina tumida), a devastating honey bee (Apis mellifera) pest. For many years, commercial beekeepers in the U.S. have used gel roach baits off-label as a method for treating SHBs. Herein, we evaluated the acute toxicity of active ingredients commonly found in gel roach baits, including abamectin, clothianidin, hydramethylnon, fipronil, and indoxacarb through topical and oral routes of exposure against SHBs and honey bees. Additionally, coumaphos, the active ingredient of the only registered in-hive control treatment for SHBs, was evaluated to provide a comparison to the gel roach bait active ingredients. Fipronil was the most toxic compound to SHBs topically (LD50 = 0.23 ng/SHB) and through pollen (LC50 = 0.06 µg/g pollen). Fipronil (LD50 = 0.31 ng/honey bee) had a selectivity ratio of 1.3, suggesting that it is more toxic to SHBs than it is to honey bees, but only to a small degree. Abamectin, clothianidin, hydramethylnon, and indoxacarb had a higher toxicity to honey bees than to SHBs through topical exposure. Our results suggest that gel roach baits and their active ingredients are toxic to honey bees and pose a serious risk to colony safety if used as in-hive treatments. [ABSTRACT FROM AUTHOR]

Summary: While there are limited data on the environmental impact of administering equine parasiticide drugs, evidence from other species indicates significant negative ecological effects. Anthelmintic drugs are excreted unchanged or metabolised to other active and/or toxic metabolites that enter the environment through direct excretion. These chemicals can have significant toxic effects on insects, such as dung beetles, earthworms and aquatic animals. Of the frequently used equine anthelmintics, ivermectin is the most ecotoxic; available evidence indicates that moxidectin is less toxic and fenbendazole appears to have little impact on dung‐colonising insects but may be toxic to aquatic organisms and fungi. There are little data regarding the ecotoxicity of pyrantel and praziquantel, although their ecotoxic effects are thought to be low. Pasture hygiene reduces pharmaceutical contamination and also helps to break the endoparasitic cycle of infectivity, thus reducing reliance on anthelmintics. Judicious and targeted use of endoparasiticides, along with pasture hygiene measures, will limit the ecotoxic effects of these drugs as well as reduce the selection pressure that drives anthelmintic resistance. Anthelmintics may also negatively impact the equine gastrointestinal microbiota. Ectoparasiticides (such as fipronil, permethrin and cypermethrin) may also have significant negative ecological effects, with a risk of contamination of both the immediate environment and water courses following topical use of these drugs. The half‐life of fipronil in the environment is variable, but it degrades into compounds which are more toxic; for example, it is highly toxic to bees and is reported to bioaccumulate in fish and can be toxic to birds. Of the synthetic pyrethroids, permethrin degrades at a faster rate than cypermethrin and may therefore have a lower ecotoxic effect. The ecotoxic effects of injectable doramectin are likely to be similar to oral ivermectin, although persistence in faeces may be significantly prolonged compared to the oral treatment route for ivermectin. [ABSTRACT FROM AUTHOR]

Background The topical veterinary drug product containing fipronil and permethrin provides an effective repellent protection and high insecticidal efficacy for dogs. Objective The objective of this study was to develop a stability-indicating high-performance liquid chromatography (HPLC) method for simultaneous detection and quantification of fipronil, permethrin, their key degradation products, and butylated hydroxytoluene (BHT) in a topical drug product. Method The two active ingredients, their degradation products, and the antioxidant (BHT) were separated by a gradient elution on a Phenomenex Kinetex C18 column (150 × 3 mm, 2.6 µm particle size) maintained at 37°C with H2O “acetonitrile “isopropyl alcohol “85% H3PO4 (65.5 + 32.5 + 4/0.0053, v/v/v/v) as mobile phase A and acetonitrile (100%) as mobile phase B. The flow rate was 0.9 mL/min, and analytes were detected and quantified at 235 nm. Results The specificity of the method was demonstrated by adequate separation of fipronil, permethrin, their degradation products, and BHT in the forced degraded finished product. The linearity of the method was demonstrated in the range of 0.2% to 150% of target analytical concentration of both active ingredients and 50% to 150% for BHT. Excellent recoveries of fipronil, permethrin, and BHT in placebo spiked active ingredient solutions in the linearity range showed sufficient accuracy of the method. The LOQ and LOD of the method were determined to be 0.2% and 0.07% of the analytical concentration. A robustness study did not identify any critical parameter that adversely affected the separation and quantification. Conclusions Here, we report the development and validation of a robust, stability-indicating HPLC method for identification and assay of fipronil, permethrin, and BHT, including estimation of fipronil's and permethrin's degradation products in a topical drug product for dogs. Highlights The new HPLC method permits the acquisition of data for all analytes of interest for a topical finished drug product containing fipronil, permethrin, and BHT. [ABSTRACT FROM AUTHOR]

Background Fipronil is a commonly used pesticide in the agricultural and animal health industries for the protection of crops and control of fleas, ticks, and chewing lice. It is difficult to obtain reproducible retention time and relative retention time (RRT) for a common hydrolytic degradation product of fipronil with the current European Pharmacopeia (EP) monograph for assay and estimation of related substances of fipronil. This situation causes misidentification, mislabeling, and/or false out-of-specification results for this hydrolytic degradation product of fipronil in bulk commercial batches during batch release and/or in the stability samples during the shelf life of a released batch. Objective This study aimed to develop a reversed-phase ultra performance liquid chromatography (UPLC) method for assay and identification of fipronil including identification and estimation of its related substances in bulk drug substance batches of fipronil and provide consistent retention time of the hydrolytic degradation product. Methods Fipronil and its related substances were separated by gradient elution on a Halo C18 column (50 mm × 2.1 mm id, 2.0 µm particle size) maintained at 40°C with 0.1% H3PO4 in H2O as mobile phase-A and acetonitrile–methanol (50 + 50, v/v) as mobile phase-B. Fipronil and its related substances were detected and quantified at 280 nm with a quantitation limit of 0.05% of the target (analytical) concentration. Results The UPLC method was able to separate all analytes of interest by gradient elution with a total run time of 7 min (approximately 40% faster than EP). Conclusion In this paper, we report the development and validation of a fast, stability-indicating reversed-phase UPLC method for assay and estimation of related substances of fipronil in stability samples and bulk batches of fipronil. Highlights The new UPLC method is approximately 40% faster than the current Ph. Eur. monograph for fipronil assay and the new method provides reproducible retention of a common hydrolytic degradation product of fipronil. [ABSTRACT FROM AUTHOR]

The study was conducted at the Students' Instructional Farm, Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya, Uttar Pradesh, India during the Kharif 2021. The investigation was aimed to evaluate specific combination insecticides against the Brown Plant Hopper and Rice Gundhi bug. Notably, the treatment Imidacloprid 40% + Fipronil 40% WG @ 500 g/ha followed by Imidacloprid 40% + Ethiprole 40% WG @ 500 g/ha demonstrated the highest effectiveness. Conversely, the least effective treatment was Chlorantraniliprole 10% + Lambda Cyhalothrin 5% ZC @ 250 ml/ha followed by Profenofos 40% + Cypermethrin 4% EC @ 1250 ml/ha when compared to the control treatment. All treatments resulted in significantly higher yields compared to the control treatment (18.17 q/ha). The maximum yield was achieved in Chlorantraniliprole 10% + Lambda Cyhalothrin 5% ZC @ 250 ml/ha producing 40.25 q/ha, while the lowest yield occurred in Triazophos 35% EC + Deltamethrin 1% EC @ 1000 ml/ha with 23.50 q/ha. [ABSTRACT FROM AUTHOR]

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The global threat that the diamondback moth (DBM) (Plutella xylostella) poses to Brassica juncea creates an urgent need to develop effective mitigation strategies. With promising findings, this study explores the potential of plant-derived antioxidants, particularly Millettia pachyloba, in mitigating DBM-induced oxidative stress. Greenhouse experiments conducted using M. pachyloba leaf ethanol extract (MPEE) at concentrations of 2, 4, 6, 8, and 10 % (w/v) showed the inhibitory effect of MPEE on DBM damage in B. juncea. The comprehensive assessment included the effectiveness of MPEE in reducing oxidative stress markers (malondialdehyde, hydrogen peroxide), augmenting metabolites (flavonoids, phenolics), enhancing anti-oxidant compounds (glutathione, ascorbic acid, total protein), and stimulating key enzymes (su-peroxide dismutase, catalase, and ascorbate peroxidase). The results were compared to controls, in which the plants were treated with water or fipronil. Fipronil and MPEE significantly reduced leaf puncturing and damage, and the impact force increased with MPEE concentration. Both types of protection reduced the content of malondialdehyde and hydrogen peroxide in leaves, stems, and roots. However, a significant increase in the content of flavonoids, phenolic and antioxidant compounds (glutathione, ascorbic acid, and proteins) and enzyme activity (superoxide dismutase, ascorbate peroxidase, and catalase) was observed. The enhancement of metabolites, enzymes, and antioxidants was comparable in plants treated with fipronil and MPEE 10%. This study, with its potential to replace synthetic fipronil with M. pachyloba extracts to reduce oxidative stress induced by Plutella xylostella on mustard plants, offers a promising solution for protection against this insect. [ABSTRACT FROM AUTHOR]

The excessive use of pesticides has led to the harmful contamination of water reservoirs. Visible-light-driven photocatalysis is one of the suitable methods for the removal of pesticides from water. Herein, the development of CBO (Co3O4-Bi2O3) as a heterogeneous catalyst for the visible light-assisted degradation of Fipronil and Acetochlor pesticides is reported. After synthesis via coprecipitation using cobalt (II) nitrate hexahydrate (Co(NO3)2·6H2O), bismuth (III) nitrate pentahydrate (Bi(NO3)3·5H2O) and sodium hydroxide (NaOH) as precursor materials, the prepared CBO was characterized using advanced techniques including XRD, EDS, TEM, SEM, FTIR, and surface area and pore size analysis. Then, it was employed as a photocatalyst for the degradation of Fipronil and Acetochlor pesticides under visible light irradiation. The complete removal of Fipronil and Acetochlor pesticides was observed over CBO photocatalyst using 50 mL (100 mg/L) of each pesticide separately within 120 min of reaction. The reaction kinetics was investigated using a non-linear method of analysis using the Solver add-in. The prepared CBO exhibited a 2.8-fold and 2-fold catalytic performance in the photodegradation of selected pesticides than Co3O4 and Bi2O3 did, respectively. [ABSTRACT FROM AUTHOR]

Pesticides are often detected in freshwater, but their impact on the aquatic environment is commonly studied based on single compounds, underestimating the potential additive effects of these mixtures. Even at low concentrations, pesticides can negatively affect organisms, altering important behaviors that can have repercussions at the population level. This study used a multi-behavioral approach to evaluate the effects of zebrafish larvae exposure to carbendazim (C), fipronil (F), and sulfentrazone (S), individually and mixed. Five behavioral tests, thigmotaxis, touch sensitivity, optomotor response, bouncing ball test, and larval exploratory behavior, were performed to assess potential effects on anxiety, fear, and spatial and social interaction. Significant changes were observed in the performance of larvae exposed to all compounds and their mixtures. Among the single pesticides, exposure to S produced the most behavioral alterations, followed by F and C, respectively. A synergistic effect between the compounds was observed in the C + F group, which showed more behavioral effects than the groups exposed to pesticides individually. The use of behavioral tests to evaluate pesticide mixtures is important to standardize methods and associate behavioral changes with ecologically relevant events, thus creating a more realistic scenario for investigating the potential environmental impacts of these compounds. [ABSTRACT FROM AUTHOR]

Bactrocera dorsalis and Bactrocera carambolae are major pests of various commodities that could cause significant losses, if not controlled. Insecticide usage is a common control carried out by farmers. The test was conducted to determine the toxicity level of several types of insecticides on the mortality of two different fruit fly species. The fruit fly population used in the study came from the collection owned by Center for Forecasting Plant Pest Organisms (BBPOPT), Karawang. The research method used was an experimental method with a Randomized Block Design. The test was carried out using the dry film method. The concentration ranges used were 0.02-1 ml/L fipronil insecticide, 0.01-0.6 ml/L ethion insecticide, 0.02-0.6 ml/L deltamethrin insecticide, and 0.02-0.8 ml/L lambda-cyhalothrin insecticide. The control treatment used was acetone alone. Each treatment was replicated thrice. Mortality was observed at 1, 3, 24, and 48 hours after treatment. Cumulative mortality at 48 hours after treatment was analyzed using probit to determine the LC50 and LC95 values at 48 hours. The results showed that the insecticide deltamethrin was the most toxic insecticide to B. carambolae with an LC50 value of 0.025 ml/L and an LC95 of 0.646 ml/L. Ethion was the most toxic insecticide for B. dorsalis with LC50 values of 0.046 ml/L and LC95 of 0.746 ml/L. The LC50 values of all insecticide treatments for two different species were below the recommended concentrations. [ABSTRACT FROM AUTHOR]

Chilli, one of the most popular vegetables in the world is infested by many insect-pests and diseases. Fipronil, a phenylpyrazole class insecticide is used to manage insect-pests on chilli. The present study aimed to analyze the dissipation patterns and residual concentrations of the fipronil and its metabolites in chilli fruits during the Kharif season of 2020–21, in semi-arid environment. In the study, fipronil was applied to the plants twice, with a 10-day gap between treatments, using a 5 % suspension concentrate. The applications were undertaken using two separate concentrations i.e. the lower dosage of 40 g a.i. ha−1 and higher dosage of 80 g a.i. ha−1. There were four sets of data for each concentration. The chilli crop was systematically sampled at predetermined intervals after the application of the second spray. The procedure encompassed utilizing the modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) technique for extraction and purification, followed by analyzing the resulting residues using Gas Chromatography Electron Capture Detector. Gas Chromatography- Mass Spectrometry was subsequently conducted for the confirmation of the findings. The research revealed that the mean initial deposit of fipronil and its metabolites (desulfinyl, sulphide, and sulfone) at the authorized dosage was determined to be 0.574, 0.123, 0.031, and 0.180 mg kg−1, respectively. In contrast, when administered at twice the prescribed dosage, the mean first deposit was 1.204, 0.230, 0.067, and 0.382 mg kg−1. The half-life values of these residues exhibited a range of 1.2–4.1 days for both dosages. A prudent waiting duration was determined for the doses, leading to the conclusion that an average interval of 7 days is deemed safe for harvesting chilli peppers. The significance of this discovery is related to the maximum residue limits of 0.001 mg kg−1 for fipronil in green chilli, as established by the Food Safety and Standards Authority of India. This study provides significant insights into fipronil's persistence and proper management in chilli plant cultivation, emphasizing the importance of following prescribed dosages and designated waiting intervals to ensure the safety of food products.

A promising alternative approach to conventional vector and rodent control practices is the use of a bait containing a rodenticide and acaricide in controlling vectors and pathogen reservoirs concurrently. In the United States, Lyme disease continues to be the most prevalent vector-borne disease with approximately 500,000 Lyme disease cases estimated each year. Previous research has demonstrated the usefulness of a low dose fipronil bait in controlling Ixodes scapularis larvae feeding on white-footed mice. However, considering white-footed mice can be an unwanted species because of their association with tick-borne disease and hantaviruses, a combination rodent and tick bait (RTB) might provide a useful alternative to encourage additional community participation in integrated tick management (ITM) efforts. The purpose of this research was to evaluate the use of RTB (0.025 % warfarin, 0.005 % fipronil) in controlling white-footed mice and I. scapularis larvae. Studies were designed in part based on Environmental Protection Agency (EPA) guidelines. A laboratory choice test was conducted to evaluate the use of RTB in controlling white-footed mice over 15-day exposure when they were exposed to an alternative diet. Mice were observed every day for mortality and signs of warfarin toxicity. A simulated field test was conducted to evaluate the use of RTB, presented in the presence of an alternative diet, in controlling I. scapularis parasitizing white-footed mice over 4-day exposure. Mice were fitted with capsules and manually infested with I. scapularis larvae. The inside of each capsule was observed to evaluate tick attachment. Replete larvae detaching from each mouse were collected. Blood was collected from all treatment group mice via cardiac puncture to determine the fipronil sulfone concentration in plasma for each animal. Results indicated that RTB would be adequately consumed in the presence of an alternative diet under laboratory and simulated field conditions. Treatment with RTB resulted in 100 % mortality of white-footed mice during 15-day exposure and prevented 100 % larvae from feeding to repletion during 4-day exposure. All mice succumbing to RTB showed signs of warfarin toxicity. All mice parasitized with ticks that were exposed to RTB had fipronil sulfone detectable in plasma, with even the lowest concentration detected (8.1 parts per billion) controlling 100 % parasitizing I. scapularis larvae. The results suggest that RTB could be a useful means of rodent and tick control for use in ITM programs.

Abstract To determine the extent of pesticide buildup and their environmental contamination, the environmental half-lives of pesticides are examined. The influence of the factors affecting the half-lives of fipronil and thiamethoxam including soil type, sterilization, temperature, and time and their interactions was studied using experimental modeling design by Minitab software. Based on the dissipation kinetics data, fipronil concentrations reduced gradually over 60 days while thiamethoxam concentrations decreased strongly. Also, fipronil and thiamethoxam dissipated more rapidly in calcareous soil than in alluvial soil. Thiamethoxam, however, disappeared more rapidly than fipronil in all treatments. Incubation at 50 °C leads to rapid the pesticide degradation. For prediction of the dissipation rate, model 5 was found to be the best fit, Residue of insecticide (%) = 15.466 − 11.793 Pesticide − 1.579 Soil type + 0.566 Sterilization − 3.120 Temperature, R2 = 0.94 and s = 3.80. Also, the predicted DT50 values were calculated by a model, DT50 (day) = 20.20 − 0.30 Pesticide − 7.97 Soil Type + 0.07 Sterilization − 2.04 Temperature. The shortest experimental and predicted DT50 values were obtained from treatment of thiamethoxam at 50 °C in calcareous soil either sterilized (7.36 and 9.96 days) or non-sterilized (5.92 and 9.82 days), respectively. The experimental DT50 values of fipronil and thiamethoxam ranged from 5.92 to 59.95 days while, the modeled values ranged from 9.82 to 30.58 days. According to the contour plot and response surface plot, temperature and sterilization were the main factors affecting the half-lives of fipronil and thiamethoxam. The DT50 values of fipronil and thiamethoxam increased in alluvial soil and soil with low temperature. In general, there is a high agreement between the experimental results and the modeled results.

Introduction: Fipronil (FIP) and thiobencarb (THIO) represent widely utilized pesticides in paddy fields, presenting environmental challenges that necessitate effective remediation approaches. Despite the recognized need, exploring bacterial consortia efficiently degrading FIP and THIO remains limited. Methods: This study isolated three unique bacterial consortia--FD, TD, and MD--demonstrating the capability to degrade FIP, THIO, and an FIP + THIO mixture within a 10-day timeframe. Furthermore, the bioaugmentation abilities of the selected consortia were evaluated in paddy soils under various conditions. Results: Sequencing results shed light on the consortia's composition, revealing a diverse bacterial population prominently featuring Azospirillum, Ochrobactrum, Sphingobium, and Sphingomonas genera. All consortia efficiently degraded pesticides at 800 µg/mL concentrations, primarily through oxidative and hydrolytic processes. This metabolic activity yields more hydrophilic metabolites, including 4-(Trifluoromethyl)-phenol and 1,4-Benzenediol, 2-methyl-, for FIP, and carbamothioic acid, diethyl-, S-ethyl ester, and Benzenecarbothioic acid, S-methyl ester for THIO. Soil bioaugmentation tests highlight the consortia's effectiveness, showcasing accelerated degradation of FIP and THIO--individually or in a mixture--by 1.3 to 13-fold. These assessments encompass diverse soil moisture levels (20 and 100% v/v), pesticide concentrations (15 and 150 µg/g), and sterile conditions (sterile and non-sterile soils). Discussion: This study offers an understanding of bacterial communities adept at degrading FIP and THIO, introducing FD, TD, and MD consortia as promising contenders for bioremediation endeavors. [ABSTRACT FROM AUTHOR]

The aquatic environment encompasses a wide variety of pollutants, from plastics to drug residues, pesticides, food compounds, and other food by-products, and improper disposal of waste is the main cause of the accumulation of toxic substances in water. Monitoring, assessing, and attempting to control the effects of contaminants in the aquatic environment are necessary and essential to protect the environment and thus human and animal health, and the study of aquatic ecotoxicology has become topical. In this respect, zebrafish are used as model organisms to study the bioaccumulation, toxicity, and influence of environmental pollutants due to their structural, functional, and material advantages. There are many similarities between the metabolism and physiological structures of zebrafish and humans, and the nervous system structure, blood–brain barrier function, and social behavior of zebrafish are characteristics that make them an ideal animal model for studying neurotoxicity. The aim of the study was to highlight the neurotoxicity of nanoplastics, microplastics, fipronil, deltamethrin, and rotenone and to highlight the main behavioral, histological, and oxidative status changes produced in zebrafish exposed to them. [ABSTRACT FROM AUTHOR]

Ants self-organize through interactions between individuals (nestmates). Therefore, it is possible that slight changes in individual behavior play an important role in interactions between individuals and subsequently lead to colony-level responses to environmental changes. While conducting research on the control/eradication of the invasive Argentine ant Linepithema humile Mayr, we observed an unusual behavior (i.e., a mandible-opening behavior: a toxicity-related behavior) displayed by ant workers after exposure to the insecticide fipronil until death. Although this phenomenon might represent a symptom of exposure to a toxin, it is possible that mandible opening behaviors are performed for the secretion of pheromones. Therefore, further studies are needed to clarify why fipronil-exposed workers exhibit mandible-opening behavior. [ABSTRACT FROM AUTHOR]

A covalent organic framework–based strategy was designed for label-free colorimetric detection of pesticides. Covalent organic framework–based nanoenzyme with excellent oxidase-like catalytic activity was synthesized. Unlike other artificial enzymes, porphyrin-based covalent organic framework (p-COF) as the oxidase mimic showed highly catalytic chromogenic activity and good affinity toward TMB without the presence of H2O2, which can be used as substitute for peroxidase mimics and H2O2 system in the colorimetric reaction. Based on the fact that the pesticide-aptamer complex can inhibit the oxidase activity of p-COF and reduced the absorbance at 650 nm in UV–Vis spectrum, a label-free and facile colorimetric detection of pesticides was designed and fabricated. Under the optimized conditions, the COF-based colorimetric probe for pesticide detection displayed high sensitivity and selectivity. Taking fipronil for example the limit of detection was 2.7 ng/mL and the linear range was 5 –500,000 ng/mL. The strategy was successfully applied to the detection of pesticides with good recovery , which was in accordance with that of HPLC–MS/MS. The COF-based colorimetric detection was free of complicated modification H2O2, which guaranteed the accuracy and reliability of measurements. The COF-based sensing strategy is a potential candidate for the sensitive detection of pesticides of interests. [ABSTRACT FROM AUTHOR]

Blood feeding and digestion are vital physiological activities essential for the survival and reproduction of ticks. Chemical acaricides viz., ivermectin, amitraz and fipronil, are known to act on the central nervous system, resulting in the mortality of ticks. The present study is focused on the effect of these acaricides on the midgut and gut enzymes of Rhipicephalus microplus. The ultra-thin sections of midgut of ivermectin-treated ticks showed irregular basal membrane and ruptured digestive vesicles. Amitraz treatment resulted in a notable decrease in digestive cells with pleats in the basal membrane, while fipronil-exposed ticks exhibited reduced digestive cells, loss of cellular integrity, and disintegration of the basal membrane and muscle layer. The gut tissue homogenate of ivermectin and fipronil treated ticks showed a significant reduction of cathepsin D level, 76.54 ± 3.20 μg/mL and 92.67 ± 3.72 μg/mL, respectively, as compared to the control group (150.0 ± 3.80 μg/mL). The leucine aminopeptidase level (4.27 ± 0.08 units/mL) was significantly decreased in the ivermectin treated ticks compared to other treatment groups. The acid phosphatase activity (29.16 ± 0.67 μmole/min/L) was reduced in the ivermectin treated group whereas, increased activity was observed in the fipronil and amitraz treated groups. All the treatment groups revealed increased alkaline phosphatase levels (17.47–26.72 μmole/min/L). The present finding suggests that in addition to the established mechanism of action of the tested acaricides on the nervous system, the alterations in the cellular profile of digestive cells and enzymes possibly affect the blood digestion process and thus the synthesis of vital proteins which are essential for vitellogenesis, and egg production in ticks. [ABSTRACT FROM AUTHOR]

Ants self-organize through interactions between individuals (nestmates). Therefore, it is possible that slight changes in individual behavior play an important role in interactions between individuals and subsequently lead to colony-level responses to environmental changes. While conducting research on the control/eradication of the invasive Argentine ant Linepithema humile Mayr, we observed an unusual behavior (i.e., a mandible-opening behavior: a toxicity-related behavior) displayed by ant workers after exposure to the insecticide fipronil until death. Although this phenomenon might represent a symptom of exposure to a toxin, it is possible that mandible opening behaviors are performed for the secretion of pheromones. Therefore, further studies are needed to clarify why fipronil-exposed workers exhibit mandible-opening behavior. [ABSTRACT FROM AUTHOR]

The phenylpyrazole insecticide fipronil has wide-ranging applications from agriculture to public health to control undesirable organisms. However, several studies have reported the residual environmental hazards of fipronil and demonstrated its harmful effects even in mammalian reproduction. Therefore, this study was conducted to demonstrate the mode of action of fipronil on mouse spermatozoa. We treated fipronil to spermatozoa and performed comprehensive function evaluations. Moreover, proteomic analyses were conducted to identify the alteration of protein expression levels in spermatozoa. Most of sperm motility and kinematic parameters and intracellular ATP levels were diminished, and the spontaneous acrosome reaction was promoted after treatment with fipronil. Proteomic analyses revealed altered expression levels of 14 proteins after treatment. These proteins have been reported to be associated with sperm-specific pathways, prominently the cytoskeleton of the sperm, "9 + 2" axoneme composition, metabolism, and fertility. Collectively, our results showed that fipronil alters sperm functional-related proteins and therefore influences male fertility. This study elucidates the possible reproductive toxic hazards associated with male infertility through aberrant suppression of sperm proteins. [ABSTRACT FROM AUTHOR]

Based on the new hapten of fipronil, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and time-resolved fluorescent immunochromatographic assay (TRFICA) for the determination of fipronil were developed. The sensitivity (IC50) of the ic-ELISA method was 2.33 ± 0.14 ng mL−1 (n = 3), and the limit of detection (LOD) (IC20) was 0.27 ± 0.02 ng mL−1 (n = 3). The cross-reaction rates of the three fipronil metabolites were all higher than 66.7%, and those of the three analogs were no more than 0.05%. The TRFICA was optimized with a handheld reader. The LOD was 0.862 ng mL−1 (n = 3). In this study, the pretreatment methods of samples such as Chinese cabbage, spinach, apple and egg, were explored. Methanol and acetonitrile were used to extract different food samples and the diluents were optimized. Three concentration levels in the spiked food samples were detected by the two methods. The range of recovery was 88.65–116.32% for ic-ELISA and 95.48–112.61% for TRFICA. In this study, the accuracy of the two methods was also judged by testing commercial quality control samples. The results showed that the accuracy was 83.75%–113.33% for ic-ELISA and 98.33–107.13% for TRFICA. [ABSTRACT FROM AUTHOR]

BACKGROUND: Insect RDL (resistant to dieldrin) receptors are essential pentameric ligand‐gated chloride channels that mediate the neuroinhibitory effect of GABA, the chief inhibitory neurotransmitter in the central nervous system. These receptors serve as primary targets for various insecticides, including noncompetitive antagonists (NCAs) such as cyclodiene organochlorines and phenylpyrazoles, as well as allosteric modulators like meta‐diamides and isoxazolines. This study focuses on a newly discovered A2′N mutation within the RDL receptors, identified in fipronil‐resistant planthoppers. Despite in vitro electrophysiological studies have proposed its role in conferring target‐site resistance, in vivo genetic functional validation of this mutation remains unexplored. RESULTS: Our research employed toxicity bioassays, assessing various Rdl genotypes against a spectrum of insecticides, including fipronil, α‐endosulfan, broflanilide, and isocycloseram. Results revealed distinct resistance profiles for A2′N and A2′S mutants, indicating different binding interactions of RDL receptors with NCAs. Significantly, the A2′N heterozygote showed substantial resistance to fipronil, despite its homozygous lethality. Molecular modeling and docking simulations further supported these findings, highlighting unique binding poses for fipronil and α‐endosulfan. CONCLUSION: This study confirmed that A2′N mutation of the RDL GABA receptor confer high resistance to fipronil in vivo. The observed resistance in A2′N mutants is likely attributable to a steric hindrance mechanism, wherein the introduction of larger side chains hampers fipronil binding, even in a heterozygous state. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Fipronil belongs to the phenylpyrazole family of insecticides and functions by interrupting the γ-aminobutyric acid system and chloride ion channels of pests. Studies have shown Fipronil can undergo several degradation pathways in the environment to form degradants that may be toxic to non-target aquatic life. In this study, a comprehensive forced degradation study of Fipronil was carried out following ICH guidelines to generate, characterize, and identify the major degradation products of Fipronil. Stress conditions included acidic, alkaline, oxidative, thermal (solid and solution states), and photolytic (solid and solution states). Separation of six major degradation products (DPs) was achieved using reversed phase high-performance liquid chromatography (HPLC) with gradient elution. The DPs were characterized and identified using HPLC-high-resolution mass spectrometry (HPLC-HRMS) and comparison of tandem MS/MS fragmentation profiles. The Fipronil dimer required isolation through semi-preparative HPLC and analysis by nuclear magnetic resonance (NMR) to elucidate and confirm its structure. The proposed structures of DPs were based upon the given degradation pathways of Fipronil. The key results and findings of this study will provide better understanding of Fipronil stability and its major degradation products including degradation/formation pathways, which would assist designing of more stable Fipronil formulations and finished products with extended shelf-life including enhanced efficacy with decreased adverse effects. [ABSTRACT FROM AUTHOR]

Intense insecticide application is thought to cause a decline in bee colonies worldwide. Bees are effective pollinators in increasing the production of agricultural commodities. The stingless bee Tetragonula laeviceps (Apidae: Meliponini) is widely cultivated and found around plantations. The insecticides used in the toxicity test were imidacloprid 200 g/L, fipronil 50 g/L, lambdacyhalothrin 25 g/L, profenofos 500 g/L, and chlorantraniliprole 50 g/L followed by a semi-field test using imidacloprid, fipronil, and profenofos insecticides on the cucumber plant. The LC50 value showed that exposure to imidacloprid, fipronil, and profenofos insecticides caused toxic effects on T. laeviceps by contact and orally. Lambda-cyhalothrin was found harmful on contact exposure, in contrast, chlorantraniliprole was harmful through oral. Classification of insecticide toxicity based on LD50 contact for imidacloprid, fipronil, lambda-cyhalothrin, and profenofos were very toxic and needed a risk assessment. However, chlorantraniliprole was classified as moderately toxic and low risk. In semi-field test results, imidacloprid and fipronil insecticides caused a significant decrease in the leave-return and bee-visiting activity on cucumber flowers. These insecticides also produced a low average yield of fruit weight. Insecticide application can affect the role of T. laeviceps as the pollinator which impacts the production of agricultural commodities. [ABSTRACT FROM AUTHOR]

With continuously reforming the current educational system, the application-oriented universities have been evolving the developing mode of the integration of industry and education. Aiming to develop the students' ability of solving problems, the infrastructure of chemistry-related courses is thus reoriented and reformatted. Classroom teaching focuses on the understanding and interpreting knowledge, while companies are aiming to reduce the production cost and improve the output for sufficient profit. The lack of communication between the two can lead students having difficulty to apply the classroom knowledge. In the teaching practice of engineering chemistry course, we combined the production of pesticide Fipronil with classroom teaching as a research topic for teaching and learning. By optimizing the chemical reaction process, we improved the production efficiency. These practices not only enrich the content of teaching topics in the classroom, but also deepen students to better understand the basic principles. Furthermore, the application of the integration practice of industrial application and classroom teaching helps students to develop their own interests in the knowledge-based problem-solving process. [ABSTRACT FROM AUTHOR]

Plant-derived chemicals are promising substances to control arthropod pests, although synthetic ones are still the most frequently used. Thus, comparative toxicological studies are needed to determine if natural substances are safe alternatives to replace the use of synthetic chemicals. This study aimed to compare the toxicity of carvacrol (natural origin), acetylcarvacrol (semi-synthetic) and a fipronil-based pesticide (synthetic). We assessed the effects of these chemicals on hemolytic activity, erythrocytes morphology and leucocyte viability using whole blood from human subjects. Additionally, DNA damage was evaluated through comet and DNA fragmentation assays. Fipronil and carvacrol caused hemolysis at concentrations ranging from 0.5 to 2.0%, whereas acetylcarvacrol did not cause hemolysis at 0.5 and 0.75%. Fipronil and carvacrol caused severe alterations in erythrocytes' morphology at 2%, such as ghost erythrocytes, elliptocyte-like shape and rouleau-like shape, presenting only 3.3 and 8.3% normal cells, respectively, at this concentration. However, 73.3% erythrocytes incubated with 2% acetylcarvacrol exhibited normal morphology. Fipronil considerably reduced leucocytes viability, decreasing it to 78% at 2%. Carvacrol and acetylcarvacrol showed no differences in leucocyte viability for 0.5 to 1.0%, but a decrease was observed for 2% carvacrol. The comet assay showed similar DNA damage for fipronil and carvacrol, but it was significantly lower for 1 and 2% acetylcarvacrol. Incubation with genomic DNA showed that only fipronil caused fragmentation of this molecule. Thus, we conclude that carvacrol and fipronil can present similar toxicity at higher concentrations. However, acetylation of carvacrol significantly reduced its toxicity to human blood cells compared with the other chemicals. [ABSTRACT FROM AUTHOR]

Lead is considered a common old chronic toxicant around the world due to expanded environmental pollution, it is likely an inevitable contaminant in food, dairy products, air etc. Also, fipronil is a wide‐ranging effective N‐phenyl pyrazole insecticide which used commonly in agriculture and public health insect control, but until now no adequate data are available on the oxidative stress, cytotoxicity, and mutagenic influence of fipronil and lead or their mixture subchronic exposure. Both xenobiotics (lead and fipronil) exert a harmful impact on reproduction, prompting the exploration of various foods for functional protection. The present study investigated the effects of camel milk treatments on reproductive problems caused by lead acetate with or without mixing with fipronil in male albino rats. Liver oxidative stress, testicular relative weight, sperm analysis, investigation of chromosomal aberration, and histopathological examination of testis were performed. The results showed that the oxidative stress was elevated in rats treated with fipronil, lead acetate, and their mixture, which were reduced through camel milk treatments. Sperm counts were decreased significantly in lead and/or fipronil exposure but significantly elevated with camel milk intoxicated treated. Sperm morphological abnormalities and chromosomal aberrations in intoxicated groups were reduced significantly in camel milk‐treated animals relative to untreated intoxicated groups. Testicular histopathological results showed moderate common degeneration of seminiferous tubules in lead and/or fipronil‐intoxicated rats which were ameliorated by camel milk treatments. Generally, it can be concluded that lead and fipronil together in a mixture resulted in or induced severe reproductive problems and oxidative stress over lead or fipronil alone. Camel milk treatment significantly decreased the harmful oxidative stress in reproductive as well as the mutagenicity disorder associated with lead and fipronil exposure in male albino rats. [ABSTRACT FROM AUTHOR]