Carbamate Pesticides Research Articles

Overcoming water quality effects in biological monitoring: a case study of amphipod in situ exposures in Ontario agricultural streams.

Bioindicators add valuable understanding of biological impacts to contaminant monitoring programs. However, attributing effects (e.g., mortality and growth impairment) to contaminant exposures is challenging because of potential confounding by environmental variables. We assessed the influence of four water quality variables (temperature, dissolved oxygen, pH, and conductivity) on contaminant effects assessments during in situ exposures of the amphipod Hyalella azteca in six agricultural and urban watersheds in southern Ontario, Canada (2005-06, 2008-10). We further tested whether sampling in specific months of the growing season would minimize confounding effects. While high toxicity from organophosphate and carbamate pesticides increased mortality and reduced growth in caged amphipods, warmer stream temperatures also affected endpoints, increasing mortality and improving growth. Seasonal patterns indicated early summer (June) as optimal for detecting impacts when: (1) stream pesticide concentrations were highest, (2) acetylcholinesterase (AChE) inhibition (a biomarker of organophosphate/carbamate exposure) was highest, and (3) stream temperature was below its seasonal peak. Specifically, higher correlations among organophosphate pesticide concentrations, AChE inhibition, and mortality indicated better attribution of cause in this month (r = 0.53-0.76, p < 0.05). Ability to discriminate between pesticide-impacted sites and reference sites was also greater than other months (June = 100% correct assignment as high-impact or reference site). Considering sampling times of stream bioindicators that maximize pesticide responses and limit confounding effects of water quality may improve the accuracy and resource-efficiency of biological monitoring programs.

Regenerable AgNPs-CdSNWs/Nanofilm as SERS substrates for sensitive detection of carbamate pesticides.

The accurate detection of carbamate pesticides popularly employed in agricultural products is critical for reducing the threat of resultant residues to human health. In this work, a regenerable nanofilm used for SERS substrate was constructed by interfacially confined self-assembly incorporating CdS nanowires (CdSNWs) and Ag nanoparticles (AgNPs). The constructed AgNPs-CdSNWs/Nanofilm could significantly enhance the Raman signals of three carbamate pesticides (metolcarb, carbaryl and aldicarb-sulfone). A broad detection linear ranged 0.001-100mg/L was achieved. The detection limits (LOD) of metolcarb, carbaryl and aldicarb-sulfone reached 0.00081mg/L, 0.00081mg/L and 0.00072mg/L with coefficients of determination of (R2) of 0.992, 0.991 and 0.992, percent recovery ranged 86.5-104.9%，88.2-105.1% and 87.0-104.5%, respectively, and relative standard deviation (RSD) values were all less than 4.0%. Results showed that the user-friendly reproducible nanofilm could be employed as simple-to-establish SERS platform for rapid detection of carbamate pesticides in food.

Selective colorimetric detection of carbosulfan based on its hydrolysis behavior and Ti3C2/AuPt nanozyme

BackgroundCarbosulfan (CBS) is a widely used carbamate pesticide in agricultural production, its easy decomposition into hypertoxic carbofuran poses serious threats to human health and food safety. Therefore, sensitive and accurate detection of CBS is of significant importance. Conventional chromatography-based techniques require expensive instruments and complicated sample pretreatment, limiting their application for fast detection. Current electrochemical and colorimetric methods for detection of pesticides based on the cascade catalytic reactions between acetylcholinesterase (AChE) and nanozymes, which exhibit inferior selectivity. Hence, selective, sensitive and fast detection of CBS is still challenging. ResultsIn this work, an AChE-free colorimetric method was proposed for selective detection of CBS based on its unique hydrolysis behavior and nanozyme. Ti3C2 nanosheets/AuPt nanoparticles (Ti3C2/AuPt NPs) with enhanced peroxidase-like activity were prepared via one-step self-reduction reaction. CBS can be hydrolyzed under acidic condition and produce -SH moieties, which could bond to Pt atoms of Ti3C2/AuPt NPs and shield the active sites of nanozyme, resulting in decreased catalytic activity. Based on the inhibitory effect on the peroxidase-like activity of Ti3C2/AuPt NPs, a colorimetric method was proposed for direct detection of CBS. Under optimal conditions, the method showed wide linear range (0.5 ng mL−1-5 μg mL−1), low limit of detection (0.342 nM), good selectivity and anti-interference ability. The feasibility of this method for practical use was confirmed by analysis of CBS in real lake water samples. SignificanceThis work proposed a simple colorimetric method for selective and fast detection of CBS, which avoided employing AChE and cascade catalytic reactions, significantly lowering the detection cost and improving detection efficiency. The method showed great potential for accurate detection of CBS in actual samples, and provided a new avenue for developing nanozyme-based colorimetric method for detection of other pesticide residues.

Small-Molecule Fluorescent Probes for Butyrylcholinesterase.

Butyrylcholinesterase plays an indispensable role in organisms, and its abnormal expression poses a significant threat to human health and safety, covering various aspects including liver-related diseases, diabetes, obesity, cardiovascular and cerebrovascular diseases, and neurodegenerative diseases. In addition, toxic substances such as organophosphorus and carbamate pesticides markedly inhibit BChE activity. BChE activity serves as a critical parameter for the clinical diagnosis of acute organophosphorus pesticide poisoning and the evaluation of organophosphorus and carbamate pesticide residues. Therefore, the accurate and reliable detection of butyrylcholinesterase activity is particularly urgent and important for in-depth analysis of its biological function, diagnosis and therapy of related diseases, drug screening and sensitive detection of pesticide residues. Fluorescent probes have become a promising tool for sensing and imaging of butyrylcholinesterase, due to its advantages of high spatio-temporal resolution, high selectivity, non-invasive, high sensitivity, and tailored molecule structures. Here, this paper provides a comprehensive overview of the research progress in the sensing, imaging and therapy of butyrylcholinesterase utilizing fluorescent probes. This paper might be a useful guideline for researchers to design new high-performance fluorescence probes for BChE, and making further contributions to this intriguing field.

The Relationship of Chollinesterase Levels to Cognitive Status In Village Farmers Pakis, Jember District

This study aims to analyze the relationship between cholinesterase levels and cognitive status in farmers in Village, Panti District, Jember Regency. High use of pesticides in the agricultural sector can increase the risk of poisoning, which has an impact on health, especially the nervous system and cognitive function. The research method used was observational with a cross-sectional design, involving 30 farmers who used organophosphate and carbamate pesticides. Cognitive status was measured using the Mini Mental State Examination (MMSE). The results showed that there was a decrease in cholinesterase levels in some farmers, but the analysis with the Spearman correlation test showed no significant relationship between cholinesterase levels and cognitive status (p &gt; 0.05). This research is expected to provide information about the impact of pesticides and the importance of using personal protective equipment for farmers

A Pyrido[1,2-a]pyrazinium bromide derivative as a fluorescent indicator for visual and rapid detection of carbamate pesticides in water

Visual and rapid detection of carbamate pesticides in lake water has not been developed. In this work, a new fluorescent pH indicator pyrido[1,2-a]pyrazinium bromide derivative was designed and synthesized. The integration of this fluorescent pH indicator and AChE-ATCh hydrolysis system allows visual and selective fluorometric detection of carbamates in lake water. Such AChE inhibition-based fluorometric reagents are well tolerated in complex aquatic environments. The detection limit for carbaryl residues in lake water reaches 0.008 mg/L. This practical fluorometric method is applicable to outdoor detection using a very simple and portable 365 nm UV instrument.

Hemoglobin targeting potential of aminocarb pesticide: Investigation into dynamics, conformational stability, and energetics in solvent environment

Aminocarb (AMC), a carbamate pesticide, due to its prevalent usage exhibits increased accumulation in the environment affecting both insects and humans. It enters the human body via food grains and be transported through bloodstream. AMC's chemical structure, containing specific molecular frameworks and functional groups, enables it to bind with proteins like albumin and hemoglobin. Given that molecules with similar architecture are known to bind with hemoglobin, we aimed to explore Aminocarb's binding capability and the potential mechanism or mode of its interaction with hemoglobin. Hb being a tetramer with a profound interface between amino acid chains offers multiple binding sites. It is therefore important to investigate the structural aspects of binding of AMC by employing various spectroscopic and in-silico methods. The surface of the α1 chain near the α1β2 interface emerges as the preferred binding site for AMC, primarily due to its conformational restrictions. In its bound state, AMC tends to maintain a relaxed conformation, closely resembling its globally optimized geometry, and resides in close proximity to the α1 chain via multiple hydrophobic contacts and water bridge as observed in molecular dynamics (MD) simulations. Fluorescence quenching experiments showed moderate binding strength (7.7 × 10⁴ L M⁻1 at 288 K, 7.8 × 10⁴ L M⁻1 at 298 K, 7.9 × 10⁴ L M⁻1 at 308 K) and spontaneous binding, driven by hydrophobic and van der Waals interactions, as indicated by enthalpy (0.80–0.91 kJ mol⁻1), entropy (0.0970–0.0974 kJ mol⁻1), and Gibbs free energy (−27.13 to - 29.08 kJ mol⁻1). Circular dichroism experiments reveal no major structural changes in Hb. Quantum chemical calculations and MD simulations reveal conformation-dependent energy differences, enhancing our understanding of AMC's binding mechanism to Hb.

A novel portable in situ analyzer for highly sensitive monitoring of organophosphorus and carbamate pesticides in food and environment

The presence of excessive residues of organophosphorus (OPs) and carbamate (CPs) pesticides in food and the environment poses a significant threat to human health and ecological sustainability. Herein, we reported a dual-readout, portable, and highly sensitive photoelectric analyzer (DPHP-analyzer) to achieve rapid and accurate monitoring of OPs and CPs. The dual signal strategy is mainly achieved by controlling the activity of acetylcholinesterase (AChE) in the presence of OPs to catalyze acetylthiocholine (ATCh) and generate thiocholine (TCh), which specifically induced the conversion of colorless Ellman's reagent (DTNB) into yellow 5-thio-2-nitrobenzoic acid (TNB). Simultaneously, the utilization of positively charged TNB as an absorber can induce a dynamic fluorescence quenching effect based on energy transfer mechanism. Fully cooperating with the above mechanism, a CD like, disposable array-based chip manufactured by 3D printing (CD-AN-chip) was designed and integrated to deliver reagents. By use of this dual-output strategy, the analyzer and chip can provide good sensitivity and selectivity for the monitoring of diazinon and carbendazim (case analysis) with a LOD 0.38 ng/mL for carbendazim. And the reproducibility, stability and practicability analysis of real sample have been thoroughly validated simultaneously. Importantly, with the features of fluorescence fingerprint map, the detector could be employed for the distinction of various analytes and further be used for monitoring the nutritional environment within residential and public settings.

High-sensitive detection of organophosphate and carbamate pesticide residues in milk based on bioluminescence method

Organophosphorus pesticides (OPs) and carbamate pesticides (CBs) are the most commonly used pesticides in agricultural cultivation. The pesticide residues in plant products can easily enter dairy cows through feed, resulting in the pesticide low-concentration residues in milk. Traditional acetylcholinesterase (AChE) inhibition-based colorimetric methods have low sensitivity and could not satisfy the detection of low-concentrations of OPs and CBs residues in dairy products. In this study, we combined firefly luciferase (FLuc)-mediated bioluminescence with the inhibition of AChE-catalyzed substrate activity by pesticides to develop a highly sensitive and rapid method for detecting OPs and CBs residues in milk. AChE breaks down D-luciferin acetate to produce D-luciferin, which is recognized by the FLuc and emits luminescence in the presence of ATP. However, the presence of OPs and CBs inhibits AChE, causing the reduction or disappearance of the luminescence signal. The luminescence signal can be detected using a hand-held luminescence photometer, eliminating the need for large instrumentation. The AChE-FLuc system accurately detected OPs and CBs in milk within 30 min, with detection limits of 7.89 ng/mL and 1.75 ng/mL, respectively. The sensitivity of this method is approximately ten times higher than that of traditional AChE inhibition methods, meeting the pesticide residue limits in milk set by China and the European Union.

First Voltammetric Determination of Karbutylate via Pencil Graphite, Glassy Carbon, and Boron-Doped Diamond Electrodes in Soil Sample

We investigated the electrochemical behavior of carbamate pesticide-type karbutylate (KB) with boron-doped diamond (BDD), glassy carbon (GC), and pencil graphite (PG) electrode, and analytical determination in real samples. Similar to organophosphate insecticides, carbamate pesticides are produced from carbamic acid and are extensively utilized in agriculture, gardens, and residences. Therefore, a rapid and simple detection of KB in real samples is important. Carbon-based electrodes are widely used in electroanalytical chemistry due to their rich surface chemistry, chemical inertness, broad potential window, low background current, and congruency for various demanding applications. Three different carbon-based electrodes were used. The effect of buffer solutions, scan rate, square wave (SWV), and differential pulse voltammetry parameters on the voltammetric response of KB was tested. The optimum working media for all three electrodes was determined as pH 2.00 phosphate buffer solution and voltammetric measurements were carried out in this media. Under optimum experimental conditions, linear calibration dependences for KB were obtained as 6.00 × 10−7–8.00 × 10−5 M, 4.00 × 10−7–8.00 × 10−5 M, and 8.00 × 10−8–8.00 × 10−5 M with a limit of detection of 2.18 × 10−7, 3.71 × 10−8 M, and 2.66 × 10−8 M by the BDD, GC, and PG electrodes, respectively, using SWV. As a result, sensitive determination of KB has been successfully performed using different carbon-based electrodes in real soil samples.

High prevalence of genus aedes aegypti resistance to carbamate, organochloride, and pyrethroid (COP) pesticides in Adonkolo Campus Federal University Lokoja, Kogi State, Nigeria

Arthropod-borne viruses pose a significant health challenge. Increased prevalence necessitates immediate attention to vector control and resistance management. WHO-approved insecticides to control these mosquitoes include Carbamate, organophosphate and pyrethroid. Adonkolo Campus, Federal University Lokoja metropolis have a disturbing presence of these vectors and therefore the research was aimed to detect the presence of resistance in genus aedes aegypti to those insecticides, DDT (organochloride, dichlorodiphenyltrichloroethane 4%), Bendiocarp (carbamate, 0.1%) and a type ii pyrethroid (Alpha cyhalothrin). The LC99 value was used on larval samples to with the help of probit and compared with the diagnostic value from approved WHO values. Increasing resistance to all three insecticides was obtained with Bendiocarb recording the highest rate at an average of 16 (64%) in all three insecticides while that of DDT stands at an average of 18 (72%) The mortality of less than 90% was declared as resistant. The insecticide susceptibility test for genus aedes. aegypti against these insecticides in Adonkolo showing resistance with a mortality rate at an average of 84% with Bendiocarb recorded the highest of 94%. The results showed that genus aedes aegypti were resistant to all three insecticides used for the WHO Bioassay and the larval test with tempho. Conclusions: The study reveals that the genus aedes aegypti population in the Adonkolo Campus tends to resist exposure to insecticide chemicals approved for vector control by WHO.

Organophosphate, carbamate and synthetic pyrethroid pesticide residues in muscle tissues of fish from Loktak Lake, a Ramsar Site in Manipur, India

The muscle tissues of Channa punctatus and Anabas testudineus collected from the Loktak Lake (a Ramsar site) and its three major feeder rivers in Manipur, Northeastern India, were analyzed using high-performance liquid chromatography for the presence of residues of organophosphorus, carbamate, and synthetic pyrethroid pesticides. Pesticide residues of all the three types were detected in the fish tissues. Pesticide residues in Channa punctatus ranged from 0.002 – 0.043 µg g-1, and from 0.008 –0.027 µg g-1in Anabas testudineus from Loktak lake in pre-monsoon and post-monsoon seasons. Pesticide residues were detected only in Anabas testudineus (0.002 – 0.078 µg g-1) in Nambul river, while these were detected only in Channa puctatus (0.001 – 0.032 µg g-1) in Moirang river. In Nambol river, pesticide concentrations ranged from 0.002 – 0.026 µg g-1 in Channa punctatus, and from 0.004 – 0.005 µg g-1 in Anabas testudineus. Among the five pesticides detected, concentrations of dichlorvos residues detected in the present study (0.027 and 0.032 µg g-1 wet weight) exceeded the Codex Alimentarius maximum residue limit (MRL) of 0.01 mg kg-1 for animal tissues. The rest of the compounds were within the MRL. None of the pesticide residues was detected in the two fish species collected from the control or reference site. The present study indicates that pesticide contamination is emerging as a threat to the water quality and aquatic biodiversity of Loktak Lake, which calls for more detailed studies on the extent and magnitude of these threats.

Recognition of organophosphate and carbamate pesticides by cholinesterase sensor arrays on the basis of enzymes from different organisms

Herein, we developed a multisensor array utilizing multiple cholinesterase (ChE) and indoxyl acetate (IDA) sensors for the detection and differentiation of trichlorfon (Tri), profenofos (Pro), methomyl (Met), carbofuran (Car), phoxim (Pho), and pyridaphenthion (Pyr). The detection mechanism involves the inactivation of ChE by organophosphates (OPs) and carbamates (CMs), leading to a reduction in the production of indoxyl groups through IDA hydrolysis. We observed distinct and varied inhibition rates of the three enzymes in response to Tri, Pro, Met, Car, Pho, and Pyr. Linear discriminant analysis (LDA) and hierarchical cluster analysis (HCA) plots illustrated the effectiveness of the system in accurately distinguishing both individual and mixed pesticides. Additionally, the platform showed the sensor array’s ability to identify pesticide mixtures and resist interference. Furthermore, the successful classification and determination of celery samples highlighted its practical applicability. This approach holds promise for developing a straightforward sensor array for detecting and discriminating pesticides in complex samples.

Comprehensive monitoring and prioritizing for contaminants of emerging concern in the Upper Yangtze River, China: An integrated approach

Contaminants of emerging concern (CECs) in aquatic environments can adversely impact ecosystems and human health even at low concentrations. This study assessed the risk of 162 CECs, including neonicotinoid pesticides, triazine pesticides, carbamate pesticides, psychoactive substances, organophosphate esters, antidepressants, per- and polyfluoroalkyl substances, and antibiotics in 10 drinking water sources and two tributaries (Jialing and Wujiang Rivers) of the Upper Yangtze River in Chongqing, China. Target screening detected 156 CECs at 0.01–2218.2 ng/L, while suspect screening via LC-QTOF-MS identified 64 CECs, with 13 pesticides, 29 pharmaceuticals and personal care products, and 2 industrial chemicals reported for the first time in the Yangtze River Basin. Risk quotient-based ecological risk assessment revealed that 48 CECs posed medium to high risks (RQ > 0.1) to aquatic life, with antibiotics (n = 20) as the main contributors. Non-carcinogenic risks were below negligible levels, but carcinogenic risks from neonicotinoids, triazines, antidepressants, and antibiotics were concerning. A multi-criteria prioritization approach integrating occurrence, physico-chemical properties, and toxicological data ranked 26 CECs as high priority. This study underscores the importance of comprehensive CEC screening in rivers and provides insights for future monitoring and management strategies.

Magnetic solid phase extraction of methiocarb pesticide from food samples prior to HPLC analysis with magnetic activated carbon cloth/zinc aluminate (magnetic ACC@ZnAl2O4) composite

Methiocarb is a carbamate pesticide and is widely used due to its short lifetime but is a health concern due to its toxicity. To address this challenge, a novel nano-sorbent (zinc aluminate hybrid doped onto a magnetic activated carbon cloth (magnetic ACC@ZnAl2O4)) was synthesized. The characterization of the composite was done using FTIR spectroscopy, SEM, XRD, and EDX. The synthesized composite was then employed for the efficient extraction of methiocarb from food samples. Under the optimum conditions of (pH: 7.0, vortex time: 0.5 min, adsorbent dose: 5 mg, initial volume of sample: 50 mL, volume of eluent: 1.0 mL), quantitative recovery values of methiocarb in food samples were obtained (80–114%). This method impresses with its exceptional sensitivity, achieving incredibly low detection (LOD: 20 µg L−1) and quantification (LOQ: 67 µg L−1) limits for methiocarb. Its efficiency is equally impressive, with high values of preconcentration factor (PF: 50) and enhancement factor (EF: 49.4), ensuring accurate and reliable analysis with a low value of relative standard deviation (RSD: 4.8%). The method’s impressive selectivity, evident in its minimal interference from other pesticides, paves the way for reliable methiocarb analysis in food samples.

Spatiotemporal variations and priority ranking of emerging contaminants in nanwan reservoir: A case study from the agricultural region in huaihe river basin in China

The presence of emerging contaminants (ECs) in drinking water sources is an increasing concern, yet limited data exists on their occurrence and risk in the upper Huaihe River Basin, an important agricultural region in Central China. This study investigated 70 ECs, including pesticide and antibiotics in surface water from drinking water source areas in Nanwan Reservoir along the upper reaches of the Huaihe River Basin to prioritize the ECs based on ecological risk and health risk assessment. A total of 66 ECs were detected in the surface water at least once at the selected 38 sampling sites, with concentrations ranging from 0.04 to 2508 ng/L. Ecological risk assessment using the risk quotient (RQ) method revealed high risks (RQ > 1) from 7 ECs in the dry season and 15 ECs in the wet season, with triazine pesticides as the main contributors. Non-carcinogenic risks were below negligible levels, but carcinogenic risks from neonicotinoid and carbamate pesticides and macrolide antibiotics were concerning for teenagers. Ciprofloxacin exhibited a high level of resistance risk during the wet season. A multi-indicator prioritization approach integrating occurrence, risk, and chemical property data ranked 6 pesticides and 3 antibiotics as priority pollutants. The results highlight EC contamination of drinking water sources in this agriculturally-intensive region and the need for targeted monitoring and management to protect water quality.

Metabolic engineering of Pseudomonas bharatica CSV86T to degrade Carbaryl (1-naphthyl-N-methylcarbamate) via the salicylate-catechol route.

Pseudomonas bharatica CSV86T displays the unique property of preferential utilization of aromatic compounds over simple carbon sources like glucose and glycerol and their co-metabolism with organic acids. Well-characterized growth conditions, aromatic compound metabolic pathways and their regulation, genome sequence, and advantageous eco-physiological traits (indole acetic acid production, alginate production, fusaric acid resistance, organic sulfur utilization, and siderophore production) make it an ideal host for metabolic engineering. Strain CSV86T was engineered for Carbaryl (1-naphthyl-N-methylcarbamate) degradation via salicylate-catechol route by expression of a Carbaryl hydrolase (CH) and a 1-naphthol 2-hydroxylase (1NH). Additionally, the engineered strain exhibited faster growth on Carbaryl upon expression of the McbT protein (encoded by the mcbT gene, a part of Carbaryl degradation upper operon of Pseudomonas sp. C5pp). Bioinformatic analyses predict McbT to be an outer membrane protein, and Carbaryl-dependent expression suggests its probable role in Carbaryl uptake. Enzyme activity and protein analyses suggested periplasmic localization of CH (carrying transmembrane domain plus signal peptide sequence at the N-terminus) and 1NH, enabling compartmentalization of the pathway. Enzyme activity, whole-cell oxygen uptake, spent media analyses, and qPCR results suggest that the engineered strain preferentially utilizes Carbaryl over glucose. The plasmid-encoded degradation property was stable for 75-90 generations even in the absence of selection pressure (kanamycin or Carbaryl). These results indicate the utility of P. bharatica CSV86T as a potential host for engineering various aromatic compound degradation pathways.IMPORTANCEThe current study describes engineering of Carbaryl metabolic pathway in Pseudomonas bharatica CSV86T. Carbaryl, a naphthalene-derived carbamate pesticide, is known to act as an endocrine disruptor, mutagen, cytotoxin, and carcinogen. Removal of xenobiotics from the environment using bioremediation faces challenges, such as slow degradation rates, instability of the degradation phenotype, and presence of simple carbon sources in the environment. The engineered CSV86-MEC2 overcomes these disadvantages as Carbaryl was degraded preferentially over glucose. Furthermore, the plasmid-borne degradation phenotype is stable, and presence of glucose and organic acids does not repress Carbaryl metabolism in the strain. The study suggests the role of outer membrane protein McbT in Carbaryl transport. This work highlights the suitability of P. bharatica CSV86T as an ideal host for engineering aromatic pollutant degradation pathways.

Advancing micro-electrometric techniques for the detection of organophosphate and carbamate residues using cricket cholinesterase.

The widespread use of organophosphate (OP) and carbamate (CM) pesticides requires efficient and cost-effective detection methods. This study introduces a micro-electrometric method using cricket cholinesterase (ChE) to detect OP and CM residues, providing a rapid and economical alternative to conventional chromatographic techniques. The parameters of the method, including the substrate concentration, incubation temperature, and incubation time, were optimized. By leveraging the sensitivity of cricket ChE to OP and CM inhibition, this approach translates enzyme inhibition into an electrical signal to quantify pesticide levels, achieving an impressive limit of detection (LOD) from 0.036 to 0.086 parts per million (ppm). This method demonstrated reproducibility and stability, making it suitable for field applications and on-site testing across various environmental matrices. This research represents a significant advancement in pesticide residue analysis with potential applications in the development of portable biosensor devices for real-time environmental monitoring and public health protection.

Sub-chronically exposing zebrafish to environmental levels of methomyl induces dysbiosis and dysfunction of the gut microbiota

The widespread use of carbamate pesticides has led to numerous environmental and health concerns, including water contamination and perturbation of endocrine homeostasis among organisms. However, there remains a paucity of research elucidating the specific effects of methomyl on gut microbial composition and physiological functions. This study aimed to investigate the intricate relationship between changes in zebrafish bacterial communities and intestinal function after 56 days of sub-chronic methomyl exposure at environmentally relevant concentrations (0, 0.05, 0.10, and 0.20 mg/L). Our findings reveal significant methomyl-induced morphological changes in zebrafish intestines, characterized by villi shortening and breakage. Notably, methomyl exposure down-regulated nutrient and energy metabolism, and drug metabolism at 0.05−0.10 mg/L, while up-regulating cortisol, inflammation-related genes, and apoptotic markers at 0.20 mg/L. These manifestations indicate physiological stress imposition and disruption of gut microbiota equilibrium, impacting metabolic processes and instigating low-grade inflammatory responses and apoptotic cascades. Importantly, changes in intestinal function significantly correlated with shifts in specific bacterial taxa abundance, including Shewanella, Rubrobacter, Acinetobacter, Bacillus, Luteolibacter, Nocardia, Defluviimonas, and Bacteroides genus. In summary, our study underscores the potential adverse effects of environmental methomyl exposure on aquatic organisms, emphasizing the necessity for further research to mitigate its repercussions on environmental health and ecosystem stability.

Sub-Chronic Methomyl Exposure Induces Oxidative Stress and Inflammatory Responses in Zebrafish with Higher Female Susceptibility.

The widespread use of carbamate pesticides has raised significant environmental and health concerns, particularly regarding water contamination and the disruption of defense systems in organisms. Despite these concerns, research on the differential impacts of pesticides on male and female organisms remains limited. This study focused on methomyl, investigating sex-specific differences in liver antioxidant defenses and inflammatory response indices in male and female zebrafish after 56 days of exposure to environmentally relevant concentrations (0, 0.05, 0.10, and 0.20 mg/L). Our findings indicate that methomyl exposure significantly increased ROS content in zebrafish livers, inducing oxidative stress and activating enzymatic antioxidant defenses such as SOD, CAT, and GSH-Px activities. Sub-chronic exposure altered the expression of apoptosis-related genes (Bax/Bcl2a and Caspases3a), resulting in liver cell apoptosis in a concentration-dependent manner, with the 0.20 mg/L concentration causing the most severe damage. Additionally, methomyl exposure at environmentally relevant concentrations triggered persistent inflammatory responses in liver tissues, evidenced by increased transcription levels of inflammatory factor genes and the activation of toll-like receptors, heightening susceptibility to exogenous allergens. It is noteworthy that oxidative damage indicators (AST, ROS, MDA) and inflammatory gene expressions (IL-1β, TNF-α) were significantly higher in female livers compared to male livers at 0.10-0.20 mg/L methomyl exposure. Consequently, our study underscores the potential adverse effects of environmental methomyl exposure on aquatic organisms and highlights the need for heightened consideration of the risks posed by environmental endocrine disruptors to female health and safety.