Carboxylesterase Activity Research Articles

Novel chlorinated oxime K870 protects rats against paraoxon poisoning better than obidoxime

The aim of this study was to determine the antidotal potential of the chlorinated oxime K870 compared to obidoxime, as a monotherapy and in combination with atropine, in paraoxon (POX)-poisoned rats. The treatment doses of oximes were chosen as 20% of their LD50 values. The protective ratio (PR) of oxime K870 with atropine was significantly higher than that of obidoxime with atropine (68.8 and 125.0, respectively). In the biochemical part of the experiment POX subcutaneously (s.c.) (0.75% LD50) was administered and followed by oxime K870 or obidoxime i.m. 1 min later. Acetylcholinesterase (AChE) activity was determined spectrophotometrically in cerebrum, cerebellum, brainstem, diaphragm, and erythrocytes. Carboxylesterase activity was determined in plasma and liver. Both oximes successfully reactivated AChE in brain (cerebrum, cerebellum, and brainstem), diaphragm and erythrocytes, but the oxime K870 performed better than obidoxime. Both oximes reactivated carboxylesterase, obidoxime better in plasma and oxime K870 better in liver. In conclusion, the oxime K870, when co-administered with atropine, is a more effective antidote than the obidoxime-atropine combination in POX-poisoned rats.

Responses of biological characteristics and detoxification enzymes in the fall armyworm to methoxyfenozide stress.

Methoxyfenozide is an insecticide with a unique mode of action on the insect ecdysone receptor and has been registered for the control of insect pests all over the world. In the present work, Spodoptera frugiperda was exposed to sublethal and lethal concentrations of methoxyfenozide to determine its impact on specific biological traits, metabolic enzyme activity, and the expression of detoxification enzymes. The result showed that 72-h posttreatment with LC50 and LC70 of methoxyfenozide significantly reduced the fecundity (eggs/female) of the F0 generation compared to those of the control group. However, the duration of the prepupal period was significantly increased. The exposure to LC10, LC30, LC50, and LC70 concentrations of methoxyfenozide significantly extended the developmental duration of larvae in F1 individuals. The fecundity of the F1 generation was significantly decreased, and the population life table parameters of F1 were also significantly affected. The activity of carboxylesterases showed little significant change, whereas the activity of glutathione S-transferases (GSTs) and cytochrome P450 monooxygenases (P450s) was significantly altered after exposure to LC10, LC30, LC50, and LC70 of methoxyfenozide. In total, 24-, 48-, and 96-h posttreatment with LC10, LC30, LC50, and LC70 of methoxyfenozide could cause upregulation of P450 genes such as CYP6AE44, CYP6B39, CYP9A26, CYP9A58, CYP9A59, and CYP9A60, as well as GST genes including GSTe3, GSTe9, GSTe10, GSTe15, GSTo2, GSTs1, GSTs5, GSTm2, and GSTm3. These findings could be instrumental in elucidating the molecular mechanisms underlying the sublethal and lethal effects of methoxyfenozide to S. frugiperda.

Effect of isolated compounds from Combretum trifoliatum on toxicity and detoxification enzymes in Nilaparvata lugens

The brown planthopper (BPH) Nilaparvata lugens (Stål) is a major insect pest of Oryza sativa that causes crop yield loss in tropical regions, including Thailand. In this study, the crude ethanolic extract of the leaves and branches of Combretum trifoliatum , its active isolated components, apigenin and camphor, and Finopril were tested for their ability to control the first to fifth instars of N. lugens. The C. trifoliatum crude extract and both allelochemicals showed insecticide potential (24 h-LC50 ~ 8.83–95.96 mg/L against each instar for crude extract), and their toxicity depended on the time of exposure. Camphor showed the higher efficacy (LD50 ~ 4.43 mg/L) and not different compared to Finopril. All plant compounds tested reduced carboxylesterase (CE) and glutathione-s-transferase (GST) activities. Camphor caused the greatest decreases in CE and GST activities after exposure, whereas apigenin induced a slight change in acetylcholinesterase activity. The results of the present study suggest that C. trifoliatum extract can be used as an insecticide to manage N. lugens populations.

Inter- and intraspecific blood-related biomarkers and chemical exposure in confined and free-living sea turtles.

The relevance of recovery centers and head-starting programs for rescue, rehabilitation, rearing, and conservation of sea turtles is recognized worldwide. In addition, these centers contribute to generating biochemical and physiological data needed to identify health markers and provide baseline values. Because of the marine ecosystems' deterioration, biomarker identification is a global priority for sea turtle conservation; nevertheless, information on specific endpoints, such as neurotoxicity and mutagenesis, is still limited in sea turtles. This study aimed to contrast a set of non-invasive blood biomarkers with ecotoxicological and clinical applications in confined green sea turtles (Chelonia mydas) compared with free-living ones from the Mexican Caribbean. Additionally, interspecific (green, hawksbill (Eretmochelys imbricata), loggerhead (Caretta caretta) turtles) differences were also evaluated. Plasmatic organochlorine pesticides (OCs) and polychlorinated biphenyl (PCBs) were also determined. The concentration ranges of uric acid, total proteins, lipids (cholesterol and triglycerides), and thyroxine of both confined and free-living green turtles fell outside the reference intervals for the species. Additionally, confined green turtles had the highest number of erythrocytic nuclear abnormalities (ENA) and elevated levels of hemoglobin, lipid peroxidation, and activity of glutathione S-transferase, glutathione peroxidase, and carboxylesterase (CE). Contrasts among confined species identified hawksbill turtles with the lowest glutathione reductase activity, green turtles with the lowest ENA frequency and CE activity, and loggerhead turtles with the highest plasmatic concentrations of PCBs and OCs. The information here provided can be used as information in health monitoring programs and for conservation and management policies at regional, national, and international level.

Maize Herbivore-Induced Volatiles Enhance Xenobiotic Detoxification in Larvae of Spodoptera frugiperda and S. litura

The release of herbivore-induced plant volatiles (HIPVs) has been recognized to be an important strategy for plant adaptation to herbivore attack. However, whether these induced volatiles are beneficial to insect herbivores, particularly insect larvae, is largely unknown. We used the two important highly polyphagous lepidopteran pests Spodoptera frugiperda and S. litura to evaluate the benefit on xenobiotic detoxification of larval exposure to HIPVs released by the host plant maize (Zea mays). Larval exposure of the invasive alien species S. frugiperda to maize HIPVs significantly enhanced their tolerance to all three of the well-known defensive compounds 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), chlorogenic acid, and tannic acid in maize and the two commonly used insecticides methomyl and chlorpyrifos. HIPV exposure also improved the larval tolerance of S. litura third instars to chlorogenic and tannic acids. Furthermore, larval exposure to either maize HIPVs or DIMBOA induced the activities of cytochrome P450 enzymes (P450s), glutathione-s-transferase (GST), and carboxylesterase (CarE) in the midguts and fat bodies of the two insects, while the induction was significantly higher by the two components together. In addition, the expression of four genes encoding uridine diphosphate (UDP)-glycosyltransferases (UGT33F28, UGT40L8) and P450s (CYP4d8, CYP4V2) showed similar induction patterns in S. frugiperda. Cis-3-hexen-1-ol, an important component in maize HIPVs, also showed the same functions as maize HIPVs, and its exposure increased larval xenobiotic tolerance and induced the detoxification enzymes and gene expression. Our findings demonstrate that HIPVs released by the pest-infested host plants are conductive to the xenobiotic tolerance of lepidopteran insect larvae. Hijacking the host plant HIPVs is an important strategy of the invasive alien polyphagous lepidopteran pest to counter-defend against the host plant’s chemical defense.

Pomegranate juice treatment reverses carbon tetrachloride (CCl4)-induced increased acetylcholinesterase activity and cell death via suppression of oxidative stress in rats

BackgroundEnvironmental pollution, including exposure to carbon tetrachloride (CCl4), poses serious health risks, particularly through oxidative stress, which may lead to neurodegenerative damage. Antioxidants, especially those found in natural products, show potential in mitigating these toxic effects. Pomegranate juice (PJ), rich in bioactive phytochemicals, has demonstrated antioxidant, anti-inflammatory, and neuroprotective properties.ObjectiveThis study aimed to investigate the protective effects of PJ on neurotoxicity induced by CCl4 in rats, assessing specific markers of oxidative stress, enzymatic activity, and apoptotic cell death.Material and MethodsTwenty-eight male Wistar rats were divided into four groups: Control, CCl4, PJ, and CCl4+PJ. The CCl4 group received intraperitoneal injections of CCl4 (0.2 ml/100 g) twice weekly for six weeks, while the PJ group received PJ orally (4 ml/kg) daily for 30 days. The CCl4+PJ group received both treatments in sequence. Brain tissues were analysed for malondialdehyde (MDA), reduced glutathione (GSH), acetylcholinesterase (AChE), glutathione S-transferase (GST), glutathione reductase (GR), and carboxylesterase (CaE) activity. Apoptotic cell death was assessed using TUNEL staining.ResultsCCl4 exposure resulted in a marked increase in MDA levels and AChE activity in brain tissue (p<0.05), alongside a significant decrease in reduced GSH levels and GST activity (p<0.05). Treatment with PJ significantly lowered MDA levels and AChE activity in the CCl4+PJ group compared to the CCl4 group (p<0.05). However, GSH levels and GST activity showed no significant changes in the CCl4+PJ group. TUNEL staining indicated a reduction in apoptotic cells in the CCl4+PJ group versus the CCl4 group, suggesting reduced cellular damage with PJ treatment (p<0.05).ConclusionsPJ demonstrates neuroprotective potential against CCl4-induced oxidative stress and neurotoxicity in rats by reducing oxidative markers and apoptosis. These findings suggest that PJ could serve as a natural protective agent against neurodegenerative risks associated with environmental pollutants like CCl4.

Two detoxification enzyme genes, CYP6DA2 and CarFE4, mediate the susceptibility to afidopyropen in Semiaphis heraclei.

Semiaphis heraclei is an important economic pest affecting Caprifoliaceae and Apiaceae plants, and chemical control is still the main effective control method in the field. Afidopyropen is a new type of pyridine cyclopropyl insecticide, which can effectively control piercing-sucking mouthparts pests and is suitable for pest resistance management. However, the detoxification mechanism of S. heraclei to afidopyropen is still poorly cleared. The insecticidal activity of afidopyropen against S. heraclei and the enzyme activity assay and synergism bioassay were evaluated. The detoxification enzyme genes were obtained by transcriptome and validated by quantitative real-time PCR (RT-qPCR). Furthermore, RNA interference was used to study the functions of detoxification enzyme genes. The activities of cytochrome P450 monooxygenases (P450s) and carboxylesterases (CarEs) were significantly increased under afidopyropen treatment. The toxicity of afidopyropen against S. heraclei was significantly increased after application the inhibitors of piperonyl butoxide and triphenyl phosphate. Sixteen P450 genes and three CarE genes were identified in the transcriptome of S. heraclei. The RT-qPCR results showed that eleven P450 genes and two CarE genes were significantly upregulated under afidopyropen treatment, and the expression of CYP6DA2 and CarFE4 was upregulated by more than 2.5 times. The expression pattern of CYP6DA2 and CarFE4 was further analyzed in different developmental stages of S. heraclei and knockdown of CYP6DA2 and CarFE4 significantly increased the susceptibility of S. heraclei to afidopyropen. The results of this study uncover the key functions of CYP6DA2 and CarFE4 in the detoxification mechanism of S. heraclei to afidopyropen, and provide a theoretical basis for the scientific use of afidopyropen in the field.

Enhancing the photo-induced oxidase-like activity of fluorescein with methyl viologen for colorimetric detection of organophosphorus pesticide

Overcoming the intrinsic low activity of most photoinduced oxidase mimics has been extremely challenging. In this work, we developed a methyl viologen (MV2+) mediated strategy to enhance the oxidase-like activity of fluorescein. The presence of MV2+ gives it a high affinity for TMB with a low Michaelis-Menten constant (Km) of 0.053 mM, which is about 2.8 times lower than that of fluorescein and with a remarkable catalytic constant (Kcat) as 0.2490 s−1, which is 3 times as high as that of fluorescein. Fluorescein diacetate (FDA) without oxidase-like activity can be hydrolyzed in situ to produce fluorescein in the presence of carboxylesterases (CaE). Based on the inhibition of CaE activity by organophosphorus pesticides (OP), a novel colorimetric signal biosensor was established with a wide linear range from 1.0 to 200 ng/mL. This work not only provides a convenient and feasible strategy for enhancing the activity of photoinduced oxidase mimics but also blazes a new pathway for the sensitive detection of OP.

Stress indicators in conservative tissues of Humboldt penguin under captivity

Humboldt penguins (Spheniscus humboldti) from the Barcelona zoo (n=9) were followed to assess their physiological stress status using conservative protocols. Corticosterone levels were measured in feathers and plasma as indicative of chronic and acute physiological stress, respectively. Other markers: B-esterases, potentially indicative of xenobiotic exposure were measured in plasma of these same individuals and reported for the first time in this species. The sensitivity to chemicals of environmental concern, employed as plastic additives, was assessed in vitro with plasma of this species using the inhibition of carboxylesterase (CE) and acetylcholinesterase enzymatic measurements. Among the tested additives, the organophosphorus flame retardants displayed the highest in vitro inhibitory potential on basal CE activity, suggesting their potential utility as biomarkers of this particular chemical class. Additionally, enzymatic measurements in plasma are determined for the first time in Humboldt penguin and can be regarded as baseline values for a potential field monitoring application.

Contact toxicity of insecticides against rice weevil, Sitophilus oryzae L. and its effect on progeny production

Post-harvest losses caused by insect pests, particularly the rice weevil, Sitophilus oryzae, pose a significant challenge in food storage facilities worldwide. To combat this pest, synthetic insecticides and fumigants are widely used. However, effective contact insecticides are scarce. Hence, the present study explored the alternatives by evaluating the contact toxicity of various insecticides against S. oryzae using glass, jute, and floor tiles as surface substrates and further examining the effect on progeny production of promising candidate insecticides. Among the insecticides tested, malathion exhibited the highest toxicity on glass and jute surfaces regardless of the exposure period. On the other hand, spinetoram proved to be the most effective on tile surface with an 8 h exposure period. Among the alternate insecticides (spinosad, spinetoram, chlorfenapyr and lambda-cyhalothrin), spinetoram was most effective with LC50 values of 155.8 and 116.9 mg/m² for 4 h and 8 h exposure, respectively, on tile surface; 204.6 and 129.0 mg/m² for 4 h and 8 h exposure, respectively, on glass surface; and 271.5 and 199.5 mg/m² for 4 h and 8 h exposure, respectively, on jute surface. Relative toxicity assessments revealed spinetoram to be 2.11 and 2.51 times more effective than deltamethrin on tile surface for 4 and 8 h of exposure, respectively whereas it was 1.14 times more effective than malathion on tile surface at 8 h exposure. Principal component analysis indicated a higher demand for insecticide doses closely associated with the structural properties of surfaces, particularly evident with jute surfaces. Furthermore, the effect on adult mortality and progeny production by malathion, spinetoram, and lambda-cyhalothrin revealed malathion as the most effective insecticide followed by spinetoram. Carboxylesterase, acetylcholinesterase, and Glutathione S-transferase (GST) activities were notably higher in deltamethrin-treated insects compared to other insecticides. The studies concluded that spinetoram can be considered an alternative to conventional insecticides for the management of S. oryzae under different storage conditions.

Rational Design of an Activatable Near-Infrared Fluorogenic Platform for In Vivo Orthotopic Tumor Imaging and Resection.

Rational and effective design of a universal near-infrared (NIR) light-absorbed platform employed to prepare diverse activatable NIR fluorogenic probes for in vivo imaging and the imaging-guided tumor resection remains less exploited but highly meaningful. Herein, mandelic acid with a core structure of 4-hydroxylbenzyl alcohol to link recognition unit, a fluorophore and a quencher was employed to prepare activatable probes. We exemplified ester as carboxylesterase (CE)-recognized unit, ferrocene as quencher and phenothiazinium as NIR fluorophore to afford fluorogenic probes termed NBS-Fe-CE and NBS-C-Fe-CE. These probes enabled the conversion toward CE with significant fluorescence increases and successfully discriminate CE activity in cells. NIR light enhances the tumor penetration and enable imaging-guided orthotopic tumor resection. This specific case demonstrated that this platform can be effectively used to construct diverse NIR probes for imaging analytes in biological systems.

Rational Design of an Activatable Near‐Infrared Fluorogenic Platform for In Vivo Orthotopic Tumor Imaging and Resection

Rational and effective design of a universal near‐infrared (NIR) light‐absorbed platform employed to prepare diverse activatable NIR fluorogenic probes for in vivo imaging and the imaging‐guided tumor resection remains less exploited but highly meaningful. Herein, mandelic acid with a core structure of 4‐hydroxylbenzyl alcohol to link recognition unit, a fluorophore and a quencher was employed to prepare activatable probes. We exemplified ester as carboxylesterase (CE)‐recognized unit, ferrocene as quencher and phenothiazinium as NIR fluorophore to afford fluorogenic probes termed NBS‐Fe‐CE and NBS‐C‐Fe‐CE. These probes enabled the conversion toward CE with significant fluorescence increases and successfully discriminate CE activity in cells. NIR light enhances the tumor penetration and enable imaging‐guided orthotopic tumor resection. This specific case demonstrated that this platform can be effectively used to construct diverse NIR probes for imaging analytes in biological systems.

Detection of carboxylesterases by an activatable NIR fluorescence probe with high selectivity in living systems

Carboxylesterases (CEs) have attracted increasingly attention in the physiological and pathological processes of many diseases such as diabetes, hepatocellular carcinoma (HCC) and drug metabolism. Selective detection of CEs activity is imperative to evaluate the pathophysiological process of CEs-related disease. Herein, a selective near-infrared (NIR) fluorescent probe (DCM-CE) with high selectivity is reported. DCM-CE was composed of dicyanoisophorone-based fluorophore and carbamate unit which is a highly selective identification group for CEs. DCM-CE exhibited good sensitivity for CEs detection at physiological pH and temperature. Furthermore, DCM-CE featured large Stokes shift (175 nm) and good at tracking the drug-induced trace change of CEs activity in HepG2 cells with little effect on cell viability. Moreover, DCM-CE was applied to monitor the activity of CEs in living mice. Taken all together, DCM-CE had extensive potential application value in detecting CEs for evaluating related diseases.

Evaluation of the effects of two commercial pesticides on Daphnia magna in different feeding environments using morphological and biochemical markers

ABSTRACT In this study, the impact of exposure to a glyphosate-based herbicide (GBH) and a trifloxystrobin-based fungicide (TBF) on Daphnia magna in diverse feeding environments was assessed through the analysis of morphological and biochemical markers. The test organisms selected for analysis were Chlorella vulgaris and D. magna. First, the 48-hour median lethal concentrations (LC50) of GBH and TBF for D. magna were determined to be 253.1 mg/L and 20.7 µg/L, respectively. Secondly, the lethality, length, width, and spin length of D. magna were evaluated following exposure to sublethal pesticide concentrations, selected based on the LC50 values, in different feeding environments. Thirdly, the activities of glutathione S-transferase (GST), glutathione reductase, catalase (CAT), carboxylesterase, and acetylcholinesterase, as well as the levels of reduced glutathione, were measured in D. magna exposed to sublethal pesticide concentrations in different feeding environments. Both pesticides caused an increase in CAT activity, while GBH also caused an increase in GST activity in the unfed and mixed-fed groups. Conversely, it can be concluded that feeding with C. vulgaris reduces oxidative stress and toxic effects since there was a lesser increase in GST and CAT activities in the C. vulgaris-fed group for both pesticides, similar to the lethality.

Synthesis of a new camphor-derived carboxylesterase-activated fluorescent probe for sensitive detection of dimethoate residues in agricultural products and its applications in biological systems

In this paper, a camphor-derived enzyme activatable probe CPA was synthesized for detecting dimethoate pesticide. The ester bond of probe CPA could be selectively hydrolyzed and fragmented in the presence of carboxylesterase (CE), which caused a remarkably enhanced green fluorescence signal at 501 nm. Probe CPA could function as an effective fluorescent platform for the sequential detection of dimethoate due to the obvious inhibition effect of dimethoate on the activity of CE. The detection limit of probe CPA to dimethoate was computed to be 0.1104 μg/mL. Even more important, CPA was effectively utilized for quantitative determination of trace dimethoate residues in agricultural products including fresh vegetables and fruits with good accuracy. Furthermore, the probe CPA could realize the detection of dimethoate in living cells and zebrafish. This work is expected to provide a highly sensitive and accurate analytical method for detecting organophosphorus pesticide residues in food samples and biological systems.

Quinclorac-resistant Echinochloa spp. promoted growth and reproduction of Laodelphax striatellus (Hemiptera: Delphacidae) probably by providing more nutrients and stable environment

Rice is an important agricultural crop that faces serious challenges from pathogens, pests, and weeds during growth stages. Meanwhile, these organisms would interact with each other to increase the level of destruction. The previous studies showed that barnyard grass (Echinochloa spp) could be used as a temporary host to increase infestation of small brown planthopper (SBPH, Laodelphax striatellus), which is one of the main polyphagous pests. Herbicides are widely used to control weeds that induce resistance development. However, little is known about the effects of increased weed resistance on insect species. In this study, we investigated the effect of quinclorac-resistant and sensitive biotypes of barnyard grass (Echinochloa crus-galli var. zelayensis; Echinochloa crus-pavonis Schult) and rice plants (Wuyujing 3) on the ecological fitness of SBPH and examined physiological indicators of plants and SBPH to explore the mechanism. Our results showed that the growth and reproduction of SBPH promoted significantly reared on quinclorac-resistant barnyard grass. From the perspectives of oxidative stress response, the activities of peroxidase (POD) increased and the activities of catalase (CAT), mixed-functional oxidase (MFO), and carboxylesterase (CarE) decreased in SBPH reared on resistant barnyard grass. Combined with the increased amino acid contents (threonine, serine, methionine, and alanine) of resistant barnyard grass E. crus-pavonis, we speculate that quinclorac-resistant barnyard grass probably provides SBPH with a more suitable environment, thus increasing the risk of SBPH.

Lethal and sublethal concentrations spirodiclofen stress may increase the adaptation of Panonychus citri (Acari: Tetranychidae).

Panonychus citri is one of the most destructive pests in citrus orchards, exhibiting varying degrees of tolerance to numerous insecticides, such as spirodiclofen. To effectively manage pests, this study explores the response of P. citri to spirodiclofen stress from the perspectives of life history, enzymatic parameters, and reproduction. The effects of two concentrations (LC30 and LC50) of spirodiclofen on the biological parameters of P. citri were evaluated by the life table method. The results showed that the development duration, fecundity, oviposition days, and lifespan were shortened, though the pre-oviposition period of two treatments was prolonged in comparison with the control. A significant decrease was recorded in the net reproductive rate (R0) and the mean generation time (T) for the two treatments. Nevertheless, the intrinsic rate of increase (r) and the rate of increase (λ) were not significantly affected in the LC30 treatment, whereas they declined in the LC50 treatment. The enzyme activity assay resulted in higher activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and carboxylesterase (CarE), among the treatments than the control. In contrast, the treatments recorded lower cytochromeP450 (CYP450) and Glutathione S-transferase (GST) activities than the control. Furthermore, the study detected that relative mRNA expression of Vitellogenin (Vg) and Vitellogenin receptor (VgR) for two treatments were lower than the control. In summary, two concentrations of spirodiclofen inhibited progeny growth and fecundity of P. citri. Additionally, the results of this study may support further research on tolerance of P. citri in response to spirodiclofen stress.

A novel ultrafast and highly sensitive NIR fluorescent probe for the detection of organophosphorus pesticides in foods and biological systems

The threat posed by organophosphorus pesticides (OPS) to food safety, human health, and the ecological environment is significant, which underscoring the need for the development of new detection tools. We designed and synthesized a NIR fluorescent probe PT-CES which targets carboxylesterase (CES), for the detection of OPS based on the principle of enzyme inhibition. The PT-CES is capable of instantaneous response to CES, exhibiting excellent stability, anti-interference capability. PT-CES realizes the quantitative detection of CES and OPS. It is noteworthy that PT-CES shows excellent stable and accurate detection ability in vegetable pesticide testing. It also enables the monitoring of CES activity in cells and liver tissue. This provides a novel tool for tracking the effect of OPS on CES activity in biological systems. Furthermore, it provides a useful method for ensuring food safety and enhancing pesticide residue analysis.

Mixture toxic mechanism of phoxim and prochloraz in the hook snout carp Opsariichthysbidens

Pesticides are usually found as mixtures in surface water bodies, even though their regulation in aquatic ecosystems is usually approached individually. In this context, this work aimed to investigate the enzymatic- and transcriptional-level responses after the mixture exposure of phoxim (PHX) and prochloraz (PRC) in the livers of hook snout carp Opsariichthys bidens. These data exhibited that co-exposure to PHX and PRC induced an acute synergistic impact on O. bidens. The activities of catalase (CAT), superoxide dismutase (SOD), carboxylesterase (CarE), and caspase3 varied significantly in most of the individual and combined challenges relative to basal values, indicating the activation of oxidative stress, detoxification dysfunction, as well as cell apoptosis. Besides, the transcriptional levels of five genes (gst, erα, mn-sod, cxcl-c1c, and il-8) exhibited more pronounced changes when subjected to combined pesticide exposure in contrast to the corresponding individual compounds. The findings revealed the manifestation of endocrine dysfunction and immune disruption. These results underscored the potential biochemical and molecular toxicity posed by the combination of PHX and PRC to O. bidens, thereby contributing to a deeper comprehension of the ecological toxicity of pesticide mixtures on aquatic organisms. Importantly, the concurrent presence of PHX and PRC might exacerbate hepatocellular damage in hook snout carps, potentially attributable to their synergistic toxic interactions. This study underscored the toxicological potency inherent in the co-occurrence of PHX and PRC in influencing fish development, thereby offering valuable insights for the risk assessment of pesticide mixtures and the safeguarding of aquatic organisms.

Carboxylesterase α-EST5 is required for the red flour beetle to metabolize mugwort essential oil

The red flour beetle (Tribolium castaneum) is a global agricultural grain storage pest that seriously jeopardizes the food safety of wheat, corn, and other grains. Carboxylesterases belong to a family of multifunctional enzymes that can participate in the metabolism of toxic substances ingested by T. castaneum, conferring drug resistance. In this study we have cloned from T. castaneum a gene encoding carboxylesterase, α-EST5, which is expressed mainly in T. castaneum late larvae and late adults. Tissue expression pattern analysis showed that α-EST5 was mainly expressed in the larval gut and adult head. Moreover, α-EST5 was able to be induced to be expressed by mugwort essential oils and significantly increased the enzymatic activity of carboxylesterase in T. castaneum after mugwort essential oil treatment. The sensitivity of T. castaneum to mugwort essential oils was significantly increased after knockdown the expression of α-EST5 using RNAi (RNA interference) technology. Through our study, we demonstrated that the carboxylesterase α-EST5 plays an important role in the detoxification of mugwort essential oils by T. castaneum. This study results provide a reference for understanding the detoxification mechanism of T. castaneum to external toxic substances.