Rapid and ultrasensitive detection of thiram and carbaryl pesticide residues in fruit juices using SERS coupled with the chemometrics technique.

A gold nanogap substrate was used to measure the thiram and carbaryl residues in various fruit juices using surface-enhanced Raman scattering (SERS). The gold nanogap substrates can detect carbaryl and thiram with limits of detection of 0.13 ppb (0.13 µgkg-1) and 0.22 ppb (0.22 µgkg-1). Raw SERS data were first preprocessed to reduce noise and undesirable effects and, were later used for model creation, implementing classification, and regression analysis techniques. The partial least-squares regression models achieved the highest prediction correlation coefficient (R2) of 0.99 and the lowest root mean square of prediction value below 0.62 ppb for both pesticide-infected juice samples. Furthermore, to differentiate between juice samples contaminated by both pesticides and control (pesticide-free), logistic-regression classification models were produced and achieved the highest classification accuracies of 100% and 99% for contaminated juice containing thiram and 100% accurate results for contaminated juice containing carbaryl. This indicates that the gold nanogap surface has significant potential for achieving high sensitivity in detecting trace contaminants in food samples.

Effects of whole life-cycle exposure to carbaryl on reproduction of female marine medaka (Oryzias melastigma) and their offspring.

Carbaryl is widely used as a highly effective insecticide which harms the marine environment. This study aimed to assess the reproductive toxicity of chronic carbaryl exposure on female marine medaka and their female offspring. After a 180-day exposure from embryonic period to adulthood, females exhibited reduced attraction to males, decreased ovulation, increased gonadosomatic index and a higher proportion of mature and atretic follicles. These reproductive toxic effects of carbaryl may stem from changes in hormone levels and transcription levels of key genes along the HPG axis. Furthermore, maternal carbaryl exposure had detrimental effects on the offspring. F1 females showed the reproductive disorders similar to those observed in F0 females. The significant changes in the transcription levels of DNA methyltransferase and demethylase genes in the F0 and F1 generations of ovaries indicate changes in their DNA methylation levels. The changes in DNA methylation levels in F1 female marine medaka may lead to changes in the expression of certain reproductive key genes, such as an increase in the transcription level of cyp19a, which may be the reason for F1 reproductive toxicity. These findings indicate that maternal exposure may induce severe generational toxicity through alterations in DNA methylation levels. This study assesses the negative impacts of whole life-cycle carbaryl exposure on the reproductive and developmental processes of female marine medaka and its female offspring, while offering data to support the evaluation of the ecological risk posed by carbaryl in marine ecosystems.

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.

Long-term carbaryl exposure leads to behavioral abnormalities and reproductive toxicity in male marine medaka through apoptosis-mediated HPA and HPG axes dysregulation.

Carbaryl is a widely used carbamate pesticide that has been detected in the marine environment, but its effects on marine fish are still unknown. This study was aimed to investigate the effects of long-term exposure of carbaryl on male marine medaka. For this purpose, we set up five exposure concentration groups of 0, 0.1, 1, 10, and 100 µg/L for 180 days. On the one hand, we observed increased aggression and decreased ability to avoid predators in males after exposure, which was affected by the levels of HPA-axis hormones, especially decreased cortisol level. On the other hand, after exposure, HPG axis hormone levels and gene transcription levels were disturbed. Males exhibited a decreased gonadosomatic index and a notable reduction in mature sperm proportion and the F1 generation displayed a significant increase in malformation rate. Additionally, the number of apoptotic cells and the transcription level of apoptosis-related genes in the brains of male marine medaka substantially increased after exposure. Apoptosis of brain cells may be responsible for the disturbance of HPA and HPG axes, consequently leading to behavioral and reproductive abnormalities. These findings provide novel insights into evaluating the toxic effects of carbaryl on male marine medaka and emphasizing the criticality of exploring the potential environmental risks posed by carbaryl in the marine environment, thus providing toxicity value basis for further strengthening marine environmental monitoring and the protection of biological resources.

Application of the QuEChERS method combined with UHPLC-QqQ-MS/MS for the determination of isoprocarb and carbaryl pesticides in Indonesian coffee.

The performance of the QuEChERS method in this study, as indicated by a high percentage (>90%) of recovery observations falling within the range of 60-140% and a sample replicate deviation (% RSD) of <20%, for the routine analysis of isoprocarb and carbaryl pesticides, has been evaluated over a 14-month period for the export of Indonesian coffee. Following a seven-day observation of the stability of these pesticides in coffee extract, it was found that the added standard calibration solution remained stable and useable for seven days when stored at 4 °C and -20 °C. This validated method, with high sensitivity (a LOQ of 0.001 mg kg-1 for isoprocarb and carbaryl), has been employed to monitor residues in Indonesian coffee exports to comply with maximum residue limits (MRLs). The samples with higher contamination levels were predominantly from robusta coffee (57.76%), followed by arabica coffee (6.17%). The detection rates for residues decreased by more than 90% in the last two months of the method's application. In the observation of coffee processing, it was found that isoprocarb residues in contaminated samples could be transferred to the processed coffee (roasted and its infusion) to a limited extent, while residues from the carcinogenic carbaryl were not detected due to evaporation. Additionally, chronic dietary risk assessment showed that contaminated samples of robusta and arabica coffees should not be considered a significant public health concern (hazard index HI < 1). However, continuous monitoring of pesticide residues in Indonesian coffee is still recommended, not only to conform to the MRLs of importing countries but also to ensure food trade.

Naïve and induced tolerance of 15 amphibian populations to three commonly applied insecticides.

Human impacts on ecological communities are pervasive and species must either move or adapt to changing environmental conditions. For environments polluted by contaminants, researchers have found hundreds of target pest species evolving increased tolerance, but we have substantially fewer cases of evolved tolerance in non-target species. When species do evolve increased tolerance, inducible tolerance can provide immediate protection and favor the evolution of increased tolerance over generations via genetic assimilation. Using a model larval amphibian (wood frogs, Rana sylvatica), we examined the tolerance of 15 populations from western Pennsylvania and eastern New York (USA), when first exposed to no pesticide or sublethal concentrations and subsequently exposed to lethal concentrations of three common insecticides (carbaryl, chlorpyrifos, and diazinon). We found high variation in naïve tolerance among the populations for all three insecticides. We also discovered that nearly half of the populations exhibited inducible tolerance, though the degree of inducible tolerance (magnitude of tolerance plasticity; MoTP) varied. We observed a cross-tolerance pattern of the populations between chlorpyrifos and diazinon, but no pattern of similar MoTP among the pesticides. With populations combined from two regions, increased tolerance was not associated with proximity to agricultural fields, but there were correlations between proximity to agriculture and MoTP. Collectively, these results suggests that amphibian populations possess a wide range of naïve tolerance to common pesticides, with many also being able to rapidly induce increased tolerance. Future research should examine inducible tolerance in a wide variety of other taxa and contaminants to determine the ubiquity of these responses to anthropogenic factors.

Evaluation of insecticide residues against spotted lanternfly (Hemiptera: Fulgoridae).

Lycorma delicatula White (Hemiptera: Fulgoridae), spotted lanternfly, is a univoltine, phloem-feeding, polyphagous and invasive insect in the United States. Although a primary host for this species is Ailanthus altissima (Mill.) Swingle, tree of heaven, L. delicatula also feeds on many other plant species, including cultivated grapevines. As this species continues to spread, it is important to develop effective management tools. Here, we evaluated the residual efficacy of 4 insecticides commonly used in tree fruit management programs: dinotefuran, bifenthrin, carbaryl, and thiamethoxam. First, all mobile life stages (early instars, late instars, and adults) of L. delicatula were exposed for 1 h to dry insecticide residues (18 h old) applied to glass or A. altissima bark surfaces. While some mortality was detected immediately following the 1 h exposure period, 100% mortality occurred within 24 h for all materials and life stages exposed on both glass and bark surfaces. To evaluate longer residual activity of these materials, groups of adult L. delicatula were introduced into cages containing A. altissima trees treated with the same individual insecticides and exposed 6 h to residues that were 18 h or 7 days old. Paired, untreated A. altissima served as controls. In these bioassays, 48 h mortality for 18 h old residue reached 95% for thiamethoxam and 100% for bifenthrin and dinotefuran. Seven-day-old bifenthrin and dinotefuran residues again yielded 100% mortality, while thiamethoxam resulted in 58% mortality, and carbaryl yielded only 13.3% and was not significantly different from the control. These results clearly document the efficacy of specific insecticide applications as management tools against L. delicatula.

Attract-and-kill for managing Popillia japonica (Coleoptera: Scarabaeidae) abundance and leaf injury in commercial vineyards.

Popillia japonica Newman (Coleoptera: Scarabaeidae) feeding negatively impacts many plant species, including grapes, potentially reducing fruit quality and yield. Chemical control, representing the current grower standard, relies on frequent broadcast applications of broad-spectrum insecticides, with alternative management strategies mostly lacking. Attract-and-kill (A&K) is a behavioral management strategy that combines semiochemical attractants and a killing agent on a substrate. This study assessed the impact of A&K on (i) the number of P. japonica adults and (ii) the percent of P. japonica feeding injury on grape foliage compared to the grower standard in commercial vineyards. This 2-year study was conducted at 3 commercial vineyards with 4 paired plots consisting of a grower standard control and an A&K treatment. The A&K treatment consisted of commercial lures, each placed on outside-edge grapevines, and weekly applications of carbaryl on the plants holding lures. The grower standard received broadcast insecticide applications at the grower's discretion. The A&K treatment experienced similar numbers of P. japonica adults and similar proportions of leaf injury compared to the grower standard. The use of A&K reduced by 96% the crop area treated with insecticides compared to the grower standard. The area treated by A&K was at the edge of the vineyards, where more leaf injury occurred regardless of treatment. A&K is a targeted approach that was effective at managing P. japonica and reducing chemical inputs on a small scale. It has the potential to be scaled up and refined to provide growers with a new management strategy.

Effects of commonly used carbamates (carbaryl and thiram) on the regulatory, secretory and motor functions of bovine cervixes in vitro.

Previously studied classes of pesticides, including organochlorines, organophosphates and pyrethroids disturb the mechanism that causes bovine myometrial contractions. Hence, the aim of this study was to investigate the effects of carbaryl and thiram, which are representative carbamate pesticides commonly used in global agriculture, on the motor and secretory functions of bovine cervixes. Additionally, the impacts of these pesticides on intra- and intercellular signaling in vitro were estimated. In this study, cervical cells or strips were obtained from cows at days 18-20 of the estrous cycle and were treated with carbaryl or thiram. Neither carbamate (10 or 100 ng/ml) exerted cytotoxic effects. Carbaryl increased the level of mRNA (at a dose of 0.1 ng/ml) and protein (at both doses, 1 and 10 ng/ml) expression for the oxytocin receptor (OXTR), while thiram (at 0.1 and 10 ng/ml or 0.1-10 ng/ml, respectively) caused the opposite effects. Moreover, the level of the second messenger inositol-trisphosphate (IP3) was decreased by carbaryl (10 ng/ml) but increased by thiram (10 ng/ml). Only thiram decreased prostaglandin-endoperoxide synthase 2 (PTGS2; 0.1 ng/ml) and aldo-keto reductase family 1, member B1 (AKR1B1; 0.1 ng/ml), and prostaglandin E synthase 2 (PTGES2; 0.1-10 ng/ml) mRNA expression, while thiram (0.1-10 ng/ml) and carbaryl (0.1 and 10 ng/ml) both decreased the release of PGF2α. Carbaryl (10 ng/ml) and thiram (10 ng/ml) also decreased the level of a gap junction protein (GAP). Moreover, carbaryl (10 ng/ml) decreased the level of myosin light chain kinase (MLCK). However, the strength of cervical contractions was increased by thiram (1 and 10 ng/ml) but decreased by carbaryl (1 and 10 ng/ml). Carbaryl increased the receptivity of cervical cells to oxytocin (OXT), but inhibited further transduction (IP3) of this signal. Hence, direct inhibition of cervical strip contraction may occur. In contrast, thiram mostly decreased the receptivity of cervical cells to OXT, while it stimulated the contraction of cervical strips. Moreover, compared to carbaryl, thiram more greatly affected the synthesis and release of prostaglandins. These results suggest that carbaryl and thiram disturb OXT signaling, PG secretion and cervical contraction in vitro.

Hinge-like paper-based dual-channel enzyme-free ratiometric fluorescent microfluidic platform for simultaneous visual detection of carbaryl and glyphosate.

On-site multi-pesticide residues detection is particularly urgent and challenging. Here, we fabricated an enzyme-free ratiometric fluorescent detection system in combination with a hinge-like dual-channel 3D microfluidic paper analytical device (3D µPAD) for simultaneous visual detection of carbaryl and glyphosate. Blue-emission 1-naphthol (Em. 470 nm) was hydrolyzed from carbaryl, while yellow-emission 2,3-diaminophenazine (Em. 570 nm) was produced with the aid of Cu2+ for glyphosate sensing. Inner-filter effect between 1-naphthol or 2,3-diaminophenazine and green-emission carbon dots (Em. 510 nm) realized two ratiometric fluorescent detection systems. Remarkable color variation of green-blue for carbaryl (50.00-1100 µΜ) and yellow-green for glyphosate (5.00-600 µΜ) were observed on a dual-channel 3D µPAD without crosstalk. Their detection limits were 1.11 and 0.63 µΜ, respectively. The strategy realized simultaneous visual detection of carbaryl and glyphosate in food/herbal with excellent accuracy (spiked recoveries, 91.00-107.2%), high precision (RSD ≤ 8.43%), and superior selectivity.

Unveiling the regulatory mechanisms of salicylate degradation gene cluster cehGHIR4 in Rhizobium sp. strain X9.

In a previous study, the novel gene cluster cehGHI was found to be involved in salicylate degradation through the CoA-mediated pathway in Rhizobium sp. strain X9 (Mol Microbiol 116:783-793, 2021). In this study, an IclR family transcriptional regulator CehR4 was identified. In contrast to other regulators involved in salicylate degradation, cehR4 forms one operon with the gentisyl-CoA thioesterase gene cehI, while cehG and cehH (encoding salicylyl-CoA ligase and salicylyl-CoA hydroxylase, respectively) form another operon. cehGH and cehIR4 are divergently transcribed, and their promoters overlap. The results of the electrophoretic mobility shift assay and DNase I footprinting showed that CehR4 binds to the 42-bp motif between genes cehH and cehI, thus regulating transcription of cehGH and cehIR4. The repeat sequences IR1 (5'-TTTATATAAA-3') and IR2 (5'-AATATAGAAA-3') in the motif are key sites for CehR4 binding. The arrangement of cehGH and cehIR4 and the conserved binding motif of CehR4 were also found in other bacterial genera. The results disclose the regulatory mechanism of salicylate degradation through the CoA pathway and expand knowledge about the systems controlled by IclR family transcriptional regulators.IMPORTANCEThe long-term residue of aromatic compounds in the environment has brought great threat to the environment and human health. Microbial degradation plays an important role in the elimination of aromatic compounds in the environment. Salicylate is a common intermediate metabolite in the degradation of various aromatic compounds. Recently, Rhizobium sp. strain X9, capable of degrading the pesticide carbaryl, was isolated from carbaryl-contaminated soil. Salicylate is the intermediate metabolite that appeared during the degradation of carbaryl, and a novel salicylate degradation pathway and the involved gene cluster cehGHIR4 have been identified. This study identified and characterized the IclR transcription regulator CehR4 that represses transcription of cehGHIR4 gene cluster. Additionally, the genetic arrangements of cehGH and cehIR4 and the binding sites of CehR4 were also found in other bacterial genera. This study provides insights into the biodegradation of salicylate and provides an application in the bioremediation of aromatic compound-contaminated environments.

Cobalt ferrite/semiconducting single-walled carbon nanotubes based field-effect transistor for determination of carbamate pesticides.

Carbaryl and carbofuran are the carbamate pesticides which have been widely used worldwide to control insects in crops and house. If the pesticides entered in to the food products and drinking water, they could cause serious health effects in humans. Therefore, the development of a rapid, simple, sensitive and selective analytical device for on-site detection of carbamates is crucial to evaluate food and environmental samples. Recently, semiconducting single-walled carbon nanotube-based field effect transistors (s-SWCNT/FETs) have shown several advantages such as high carrier mobility, good on/off ratio, quasi ballistic electron transport, label-free detection and real-time response. Herein, cobalt ferrite (CFO) nanoparticles decorated s-SWCNTs have been prepared and used to bridge the source and drain electrodes. As-prepared CFO/s-SWCNT/FET had been used for the non-enzymatic detection of carbaryl and carbofuran. When used as a sensing platform, the CFO/s-SWCNT hybrid film exhibited high sensitivity, and selectivity with a wide linear range of detection from 10 to 100 fMand the lowest limit of detections for carbaryl (0.11 fM) and carbofuran (0.07 fM) were estimated. This sensor was also used to detect carbaryl in tomato and cabbage samples, which confirmed its practical acceptance. Such performance may be attributed to the oxidation of carbamates by potent catalytic activity of CFO, which led to the changes in the charge transfer reaction on the s-SWCNTs/FET conduction channel. This work presents a novel CFO/s-SWCNT based sensing system which could be used to quantify pesticide residues in food samples.

UDP-glucuronosyltransferase is involved in susceptibility of Chironomus kiiensis Tokunaga, 1936 (Diptera: Chironomidae) to insecticides.

UDP-glucuronosyltransferases (UGTs) could transform various exogenous and endogenous compounds, which help detoxification of pesticides in insects. To investigate the role of UGTs in the detoxification metabolism of insecticides in Chironomus kiiensis, CkUGT302M1, CkUGT302N1, CkUGT308N1 and CkUGT36J1 genes were identified with 1449-1599 bp encoding 482-532 amino acids. Four UGT genes shared 40.86∼53.36% identity with other homologous insect species, and expressed in all developmental stages, notably in the larval and adult stages. Expression of CkUGTs was higher in the gastric caecum, midgut and head. Moreover, CkUGTs expression and activity were significantly increased in C. kiiensis larvae in exposure to sublethal concentrations of carbaryl, deltamethrin and phoxim, respectively. To further explore the functions of UGT genes, the CkUGT308N1 was effectively silenced in 4th instar C. kiiensis larvae by RNA interference, which resulted in the mortality of dsCkUGT308N1 treated larvae increased by 71.43%, 111.11% and 62.50% under sublethal doses of carbaryl, deltamethrin and phoxim at the 24-h time point, respectively. The study revealed that the CkUGT308N1 gene in C. kiiensis could contribute to the metabolism of pesticides and provide a scientific basis for evaluating the water pollution of pesticides.

Effective intracellular release of ibuprofen triggered by thermosensitive magnetic nanocarriers.

Stimuli-responsive nanocarriers are being widely applied in the development of new strategies for the diagnosis and treatment of diseases. An inherent difficulty in general drug therapy is the lack of precision with respect to a specific pathological site, which can lead to toxicity, excessive drug consumption, or premature degradation. In this work, the controlled drug delivery is achieved by using magnetite nanoparticles coated with mesoporous silica with core-shell structure (MMS) and grafted with the thermoresponsive polymer poly [N-isopropylacrylamide-co-3-(trimethoxysilyl)propyl methacrylate] (MMS-P). The efficiency of MMS-P as a temperature-controlled drug delivery system was evaluated by in vitro release experiments using ibuprofen (IBU) in various mammalian cell models. Further, the effects of IBU as a photoprotectant in cells exposed to photodynamic therapy (PDT) in a carbaryl-induced neurodegenerative model were evaluated. The results showed that MMS-P nanocarriers do not exhibit cytotoxicity in HepG2 cells at high doses such as 7600 µg mL-1. Pre-incubation of MMS-P charged with IBU showed no effect on the PDT in N2A cells; however, it produced a further decrease in the viability of HepG2 cells, leading to a reduction to PDT resistance. On the other hand, a cytoprotective effect against carbaryl toxicity in N2A cells was observed in IBU administrated by MMS-P, which confirms the effective intracellular IBU uptake by means of MMS-P. These results encourage the potential application of MMS-P as a drug delivery system and confirm the effect of IBU as a cytoprotective agent in a neurodegenerative model.

Pesticide concentration in three selected fish species and human health risk in the Lake Tana sub-basin, Ethiopia.

Pesticide use has increased in the Lake Tana sub-basin due to increased agricultural activity, potentially endangering nontargeted organisms. To assess its potential impact on fish health and fish-consuming human populations, pesticide concentrations in the fillet and liver tissue of three fish species, namely Labeobarbus megastoma, Labeobarbus tsanensis, and Oreochromis niloticus, were investigated in Lake Tana. Fish samples were taken from the lake near the rivers of Ribb and Gumara, which flow through agricultural areas where considerable amounts of pesticides have been applied. A total of 96 fish samples were collected. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) revealed the presence of ten pesticides. Pyrimethanil was frequently detected in 96% of liver and 65% of fillet samples at a median concentration of 33.9 µg kg-1 and 19.7 µg kg-1, respectively. The highest concentration of pyrimethanil was found in L. megastoma (1850.0 µg kg-1). Labeobarbus megastoma also had the highest concentration of oxamyl (507.0 µg kg-1) and flazasulfuron (60.1 µg kg-1) detected in the liver tissue. The highest concentration of carbaryl (56.5 µg kg-1) was found in the liver tissue of O. niloticus. Fish tissue samples from the two study sites contained pyrimethanil, oxamyl, carbaryl, and flazasulfuron. Only pyrimethanil showed a statistically significant difference between the two sites and the species L. megastoma and L. tsanensis. The amounts of pesticides found in the fish species pose no direct risk to the health of fish consumer human population. However, the results show that the lake ecosystem needs immediate attention and regular monitoring of the rising pesticide usage in the lake watershed.

Preparation of biochar-based surface molecularly imprinted polymers and evaluation of their selective adsorption and removal of carbaryl from rice and corn.

The residue of carbaryl in food is a threat to human health. In this study, activated soybean shell biochar (A-SBC) was used as a carrier, methacrylic acid (MAA) was used as a functional monomer, and carbaryl was used as a template molecule to synthesize the activated biochar surface molecularly imprinted polymer (A-SBC@MIP). The synthesized A-SBC@MIP was characterized by SEM, FT-IR, XRD and XPS techniques, and then applied as adsorbent for carbaryl removal. The adsorption capacity of A-SBC@MIP for carbaryl was 8.6 mg‧g-1 and the imprinting factor was 1.49 at the optimum ionic strength and pH. The kinetic and isothermal data indicated that it had fast mass transfer rate and high binding capacity(Qmax=47.9 mg‧g-1). A-SBC@MIP showed good regenerative properties and the adsorption of carbaryl was excellent in its structural analogues. A solid-phase extraction (SPE) column composed of A-SBC@MIP was developed for the detection of rice and corn under optimized conditions, with recoveries of 93-101% for the spiked carbaryl. The limit of detection (LOD) of the method was 3.6 µg‧kg-1 with good linearity (R2=0.994) in the range of 0.01-5.00 mg‧L-1. The results show that the developed MIPs-SPE can enrich carbaryl from food samples as a specific and cost-effective method.

Dietary deprivation reduces the deleterious effects of carbaryl on the survival and activity of both catalase and acetylcholinesterase in earthworms.

Dietary restriction (DR) and dietary deprivation (DD) have been shown to be significantly beneficial in terms of lifespan gains and stress alleviation in invertebrate and vertebrate species. Such beneficial effects, however, have yet to be clearly assessed in the presence of chemical stressors. We conducted a comparative evaluation of the toxicity of carbaryl in Eisenia fetida individuals subjected to a full diet (FD), DR and DD. For 14 days, groups of ten worms subjected to FD received 5 g oatmeal, those subjected to DR received 2.5 g oatmeal, and those subjected to DD received 0 g oatmeal weekly. We evaluated concentrations of 0, 7, 14 and 28 mg carbaryl.kg-1 soil and measured effects on survival, reproduction, biomass and biomarkers (Catalase- CAT and acetylcholine esterase- AChE). Carbaryl caused a total inhibition of reproduction in all the treatments. For each diet level, the 14-day LC50 s were higher than 28 mg.kg-1, but the 14-day LC20 s for the earthworms subjected to FD, DR, and DD were 11.24, 20.51 and > 28 mg.kg-1, respectively. This showed that the toxicity of carbaryl consistently decreased with the reduction in nutrients. Carbaryl caused a significant weight loss in the worms subjected to FD in the 7 mg.kg-1 treatment (P = 0.0065). Such weight loss was not found in any of the other treatments and diets. Both CAT and AChE were significantly inhibited in the two highest treatments (P = 0.0071 and P = 0.0073, respectively). Interestingly, the earthworms subjected to DD showed relatively lower biomarker inhibition, indicating a greater tolerance to oxidative and neurotoxic stresses in these starved earthworms. For all endpoints investigated, aside from reproduction, the starved earthworms fared better under carbaryl toxicity than those given the other diets. Overall, a positive correlation was observed between the amount of food and chemical toxicity as mortality rates, AChE and CAT inhibition increased with the increased amount of nutrients given to the worms. These results show that, in the presence of a chemical stressor, the beneficial effects of DR and DD were variably manifest for select lifecycle parameters and biomarker responses, further suggesting dietary reduction as a non-genetic intervention that could help extend lifespan and alleviate stress even under a chemical insult.

A bispecific nanobody with high sensitivity/efficiency for simultaneous determination of carbaryl and its metabolite 1-naphthol in the soil and rice samples.

The simultaneous determination of carbaryl and its metabolite 1-naphthol is essential for risk assessment of pesticide exposure in agricultural and environmental samples. Herein, several bispecific nanobodies (BsNbs) with different lengths of hydrophilic linkers and junction sites were prepared and characterized for the simultaneous recognition of carbaryl and its metabolite 1-naphthol. It was found that the affinity of BsNbs to the analytes could be regulated by controlling linker length and linking terminal. Additionally, molecular simulation revealed that linker lengths affected the conformation of BsNbs, leading to alteration in sensitivity. The BsNb with G4S linker, named G4S-C-N-VHH, showing good thermal stability and sensitivity was used to develop a bispecific indirect competitive enzyme-linked immunosorbent assay (Bic-ELISA). The assay demonstrated a limit of detection of 0.8 ng/mL for carbaryl and 0.4 ng/mL for 1-naphthol in buffer system. Good recoveries from soil and rice samples were obtained, ranging from 80.0% to 112.7% (carbaryl) and 76.5%-110.8% (1-naphthol), respectively. Taken together, this study firstly provided a BsNb with high sensitivity and efficiency against environmental pesticide and its metabolite, and firstly used molecular dynamics simulation to explore the influence of linker on recognition. The results are valuable for the application of immunoassay with high efficiency in the fields of environment and agriculture.

Updating integrated mite management 50 years later: comparing laboratory pesticide susceptibility of a 'new' generalist predatory mite to a cornerstone specialist predator.

BACKGROUND: Historically, integrated mite management in Washington apple orchards has focused on conservation of the predatory mite Galendromus occidentalis (Nesbitt) to reduce secondary pest mite pressure. However, pesticide use has changed to include more selective products, coinciding with a shift in the predatory mite community composition to include a new major predator, Amblydromella caudiglans (Schuster). There is evidence that A. caudiglans is more pesticide sensitive than G. occidentalis. Therefore, updates to pesticide selectivity recommendations are needed to conserve this 'new' key predator. Using bioassays, we examined the lethal (female mortality) and sublethal effects (fecundity, egg hatch, larval survival) of 4 fungicides and 11 insecticides on A. caudiglans, to determine whether existing conservation recommendations can be applied to this predatory mite. Susceptibility was compared with prior research on G. occidentalis. RESULTS: Mancozeb was the least selective fungicide tested on A. caudiglans; it caused high acute toxicity and sublethal effects. Carbaryl was the least selective insecticide and caused 100% mortality. Captan was the most selective fungicide. Chlorantraniliprole and cyantraniliprole were the most selective insecticides and therefore least likely to disrupt biological control by A. caudiglans. Non-target effects on A. caudiglans and G. occidentalis were similar, but A. caudiglans experienced higher mortality to some broad-spectrum insecticides. CONCLUSIONS: All the products tested had some non-target effects on A. caudiglans. However, A. caudiglans sensitivity to most tested pesticides was similar to that of G. occidentalis. In general, existing spray recommendations for conserving G. occidentalis can be adjusted slightly and applied to A. caudiglans conservation. © 2023 Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

The sensitivity of the zebrafish embryo coiling assay for the detection of neurotoxicity by compounds with diverse modes of action.

In the aim to determine neurotoxicity, new methods are being validated, including tests and test batteries comprising in vitro and in vivo approaches. Alternative test models such as the zebrafish (Danio rerio) embryo have received increasing attention, with minor modifications of the fish embryo toxicity test (FET; OECD TG 236) as a tool to assess behavioral endpoints related to neurotoxicity during early developmental stages. The spontaneous tail movement assay, also known as coiling assay, assesses the development of random movement into complex behavioral patterns and has proven sensitive to acetylcholine esterase inhibitors at sublethal concentrations. The present study explored the sensitivity of the assay to neurotoxicants with other modes of action (MoAs). Here, five compounds with diverse MoAs were tested at sublethal concentrations: acrylamide, carbaryl, hexachlorophene, ibuprofen, and rotenone. While carbaryl, hexachlorophene, and rotenone consistently induced severe behavioral alterations by ~ 30 h post fertilization (hpf), acrylamide and ibuprofen expressed time- and/or concentration-dependent effects. At 37-38 hpf, additional observations revealed behavioral changes during dark phases with a strict concentration-dependency. The study documented the applicability of the coiling assay to MoA-dependent behavioral alterations at sublethal concentrations, underlining its potential as a component of a neurotoxicity test battery.