Fabrication and characterization of polyvinyl alcohol-chitosan composite nanofibers for carboxylesterase immobilization to enhance the stability of the enzyme.

Electrospinning stands out as a flexible and viable method, presenting designed nanoscale materials with customized properties. This research demonstrates the immobilization of carboxylesterase protein Ha006a, reported for its adequacy in pesticide bioremediation by utilizing the electrospinning strategy. This strategy was utilized to create nanofibers by incorporating variable mixtures of biodegradable and cost-effective polyvinyl alcohol (PVA)-chitosan (CS) nanofiber solution (PVA100, PVA96, PVA94, PVA92 and PVA90). All the mixtures were electrospun at a reliable voltage of 21 kV, maintaining a gap of 12 cm from the nozzle. The Ha006a, sourced from Helicoverpa armigera, was consolidated into the optimized PVA90 polymer mixture. The electrospun nanofibers experienced comprehensive characterization utilizing distinctive microscopy and spectroscopy procedures counting FESEM, TGA, XRD and FTIR. The comparative investigation of the esterase property, ideal parameters and stability of the unbound and bound/immobilized Ha006a was scrutinized. The results uncovered an essential elevation in the ideal conditions of enzyme activity post-immobilization. The PVA-CS control nanofiber and Ha006a-PVA-CS showed a smooth structure, including an average breadth of around 170.5 ± 44.2 and 222.5 ± 66.5 nm, respectively. The enzyme-immobilized nanofibers displayed upgraded stability and comprehensive characterization of the nanofiber, which guaranteed genuineness and reproducibility, contributing to its potential as a potent device for bioremediation applications. This investigation opens the way for the manufacture of pesticide-resistant insect enzyme-based nanofibers, unlocking their potential for assorted applications, counting pesticide remediation and ensuring environmental sustainability.

Enzyme-based sensor for the real-time detection of atrazine: Evidence from electrochemical and docking studies.

This study focused on strategically employing the carboxylesterase enzyme Ha006a, derived from the pesticide-resistant microorganism Helicoverpa armigera, to detect atrazine. A comprehensive analysis through biochemical, biophysical and bioinformatics approaches was conducted to determine the interaction between the Ha006a protein and the herbicide atrazine. These experimental findings elucidated the potential of leveraging the inherent pesticide sequestration mechanism of the Ha006a enzyme for sensor fabrication. Numerous optimizations were undertaken to ensure the precision, reproducibility and convenient storage of the resulting electrochemical sensor, Ha006a/MCPE. This biosensor exhibited exceptional performance in detecting atrazine, demonstrating outstanding selectivity with a lower limit of detection of 5.4 µM. The developed biosensor has emerged as a reliable and cost-effective green tool for the detection of atrazine from diverse environmental samples. The Ha006a-based biosensor fabrication has expanded the possibilities for the efficient integration of insect enzymes as analytical tools, paving the way for the design of cost-effective biosensors capable of detecting and quantifying pesticides.

Identification and Functional Characterization of Carboxylesterase Genes Involved in Spirodiclofen Resistance in Panonychus citri (McGregor).

Overexpression of carboxyl/cholinesterase (CCE) genes has been reported to be associated with many cases of pesticide resistance in arthropods. However, it has been rarely documented that CCE genes participate in spirodiclofen resistance in Panonychus citri. In previous research, we found that spirodiclofen resistance is related to increased P450 and CCE enzyme activities in P. citri. In this study, we identified two CCE genes, PcCCE3 and PcCCE5, which were significantly upregulated in spirodiclofen-resistant strain and after exposure to spirodiclofen. RNA interference of PcCCE3 and PcCCE5 increased the spirodiclofen susceptibility in P. citri. In vitro metabolism indicated that PcCCE3 and PcCCE5 could interact with spirodiclofen, but metabolites were detected only in the PcCCE3 treatment. Our results indicated that PcCCE3 participates in spirodiclofen resistance through direct metabolism, and PcCCE5 may be involved in the spirodiclofen resistance by passive binding and sequestration, which provides new insights into spirodiclofen resistance in P. citri.

In Situ Visualizing Carboxylesterase Activity in Type 2 Diabetes Mellitus Using an Activatable Endoplasmic Reticulum Targetable Proximity Labeling Far-Red Fluorescent Probe.

Carboxylesterase (CE), an enzyme widely present in organisms, is involved in various physiological and pathological processes. Changes in the levels of CEs in the liver may predict the presence of type 2 diabetes mellitus (T2DM). Here, a novel dicyanoisophorone (DCI)-based proximity-labeled far-red fluorescent probe DCI2F-Ac with endoplasmic reticulum targeting was proposed for real-time monitoring and imaging of the CEs activity. DCI2F-Ac featured very low cytotoxicity and biotoxicity and was highly selective and sensitive for CEs. Compared with traditional CEs probes, DCI2F-Ac was covalently anchored directly to CEs, thus effectively reducing the loss of in situ fluorescent signals due to diffusion. Through the "on-off" fluorescence signal readout, DCI2F-Ac was able to distinguish cell lines and screen for CEs inhibitors. In terms of endoplasmic reticulum (ER) stress, it was found that thapsigargin (Tg) induced upregulation of CEs levels but not tunicamycin (Tm), which was related to the calcium homeostasis of the ER. DCI2F-Ac could efficiently detect downregulated CEs in the livers of T2DM, and the therapeutic efficacy of metformin, acarbose, and a combination of these two drugs was assessed by tracking the fluctuation of CEs levels. The results showed that combining metformin and acarbose could restore CEs levels to near-normal levels with the best antidiabetic effect. Thus, the DCI2F-Ac probe provides a great opportunity to explore the untapped potential of CEs in liver metabolic disorders and drug efficacy assessment.

Dual-reporter fluorescent probe for precise identification of liver cancer by sequentially responding to carboxylesterase and polarity.

Early treatment significantly improves the survival rate of liver cancer patients, so the development of early diagnostic methods for liver cancer is urgent. Liver cancer can develop from viral hepatitis, alcoholic liver, and fatty liver, thus making the above diseases share common features such as elevated viscosity, reactive oxygen species, and reactive nitrogen species. Therefore, accurate differentiation between other liver diseases and liver cancer is both a paramount practical need and challenging. Numerous fluorescent probes have been reported for the diagnosis of liver cancer by detecting a single biomarker, but these probes lack specificity for liver cancer in complex biological systems. Obviously, using multiple liver cancer biomarkers as the basis for judgment can dramatically improve diagnostic accuracy. Herein, we report the first fluorescent probe, LD-TCE, that sequentially detects carboxylesterase (CE) and lipid droplet polarity in liver cancer cells with high sensitivity and selectivity, with linear detection of CE in the range of 0-6 U/mL and a 65-fold fluorescence enhancement in response to polarity. The probe first reacts with CE and releases weak fluorescence, which is then dramatically enhanced due to the decrease in lipid droplet polarity in liver cancer cells. This approach allows the probe to enable specific imaging of liver cancer with higher contrast and accuracy. The probe successfully achieved the screening of liver cancer cells and the precise identification of liver cancer in mice. More importantly, it is not disturbed by liver fibrosis, which is a common pathological feature of many liver diseases. We believe that the LD-TCE is expected to be a powerful tool for early diagnosis of liver cancer.

The ester-containing prodrug NT-0796 enhances delivery of the NLRP3 inflammasome inhibitor NDT-19795 to monocytic cells expressing carboxylesterase-1.

NT-0796 is an ester prodrug which is metabolized by carboxylesterase-1 (CES1) to yield the carboxylic acid NDT-19795, an inhibitor of the NLR family pyrin domain-containing protein 3 (NLRP3) inflammasome. When applied to human monocytes/macrophages which express CES1, however, NT-0796 is much more potent at inhibiting NLRP3 inflammasome activation than is NDT-19795. Comparison of the binding of NDT-19795 and NT-0796 in a cell-based NLRP3 target engagement assay confirms that NDT-19795 is the active species. Moreover, microsomes expressing CES1 efficiently convert NT-0796 to NDT-19795, confirming CES1-dependent activation. To understand the basis for the enhanced potency of the ester prodrug species in human monocytes, we analyzed the accumulation and de-esterification of NT-0796 in cultured cells. Our studies reveal NT-0796 rapidly accumulates in cells, achieving estimated cellular concentrations above those applied to the medium, with concomitant metabolism to NDT-19795 in CES1-expressing cells. Using cells lacking CES1 or a poorly hydrolysable NT-0796 analog demonstrated that de-esterification is not required for NT-0796 to achieve high cellular levels. As a result of a dynamic equilibrium whereby NDT-19795 formed intracellularly is subsequently released to the medium, concentrations of NT-0796 sufficient to inhibit NLRP3 can be completely metabolized to NDT-19795 resulting in a transient pharmacodynamic response. In contrast, when NDT-19795 is applied directly to cells, observed cell-associated levels are below those present in the medium and remain stable over time. Dynamics observed within the context of a closed tissue culture system highlight the utility of NT-0796 as a vehicle for delivering the NDT-19795 acid payload to CES1 expressing cells.

Thiamethoxam toxicity on the stingless bee Friesiomelitta varia: LC50, survival time, and enzymatic biomarkers assessment.

Bees play a crucial role as pollinating insects in both natural and cultivated areas. However, the use of pesticides, such as thiamethoxam, has been identified as a contributing factor compromising bee health. The current risk assessment primarily relies on the model species Apis mellifera, raising concerns about the applicability of these assessments to other bee groups, including stingless bees. In this study, we investigated the acute toxicity of thiamethoxam on the stingless bee Frieseomelitta varia by determining the average lethal concentration (LC50) and mean lethal time (LT50). Additionally, we evaluated the enzymatic profile of Acetylcholinesterase (AChE), Carboxylesterase-3 (CaE-3), and Glutathione S-Transferase (GST), in the heads and abdomens of F. varia after exposure to thiamethoxam (LC50/10). The LC50 of thiamethoxam was determined to be 0.68 ng ai/µL, and the LT50 values were 37 days for the control group, 25 days at LC50/10, and 27 days at LC50/100. The thiamethoxam significantly decreased the survival time of F. varia. Furthermore, the enzymatic profile exhibited differences in CaE3 activity within one day in the heads and ten days in the abdomen. GST activity showed differences in the abdomen after one and five days of thiamethoxam exposure. These findings suggests that the abdomen is more affected than the head after oral exposure to thiamethoxam. Our study provides evidence of the toxicity of thiamethoxam at both the cellular and organismal levels, reinforcing the need to include non-Apis species in pollinator risk assessments. and provide solid arguments for bee protection.

Identification and expression of MarCE, a marine carboxylesterase with synthetic ester-degrading activity.

Carboxylic ester hydrolases with the capacity to degrade polyesters are currently highly sought after for their potential use in the biological degradation of PET and other chemically synthesized polymers. Here, we describe MarCE, a carboxylesterase family protein identified via genome mining of a Maribacter sp. isolate from the marine sponge Stelligera stuposa. Based on phylogenetic analysis, MarCE and its closest relatives belong to marine-associated genera from the Cytophaga-Flavobacterium-Bacteroides taxonomic group and appear evolutionarily distinct to any homologous carboxylesterases that have been studied to date in terms of structure or function. Molecular docking revealed putative binding of BHET, a short-chain PET derivative, onto the predicted MarCE three-dimensional structure. The synthetic ester-degrading activity of MarCE was subsequently confirmed by MarCE-mediated hydrolysis of 2 mM BHET substrate, indicated by the release of its breakdown products MHET and TPA, which were measured, respectively, as 1.28 and 0.12 mM following 2-h incubation at 30°C. The findings of this study provide further insight into marine carboxylic ester hydrolases, which have the potential to display unique functional plasticity resulting from their adaptation to complex and fluctuating marine environmentsw.

Various functions of detoxification enzymes against insecticides in Nilaparvata lugens selected by toxicity assays and RNAi methods.

The brown planthopper (BPH), Nilaparvata lugens is a devastating agricultural pest of rice, and they have developed resistance to many pesticides. In this study, we assessed the response of BPH nymphs to nitenpyram, imidacloprid, and etofenprox using contact and dietary bioassays, and investigated the underlying functional diversities of BPH glutathione-S-transferase (GST), carboxylesterase (CarE) and cytochrome P450 monooxygenase (P450) against these insecticides. Both contact and ingestion toxicity of nitenpyram to BPH were significantly higher than either imidacloprid or etofenprox. Under the LC50 concentration of each insecticide, they triggered a distinct response for GST, CarE, and P450 activities, and each insecticide induced at least one detoxification enzyme activity. These insecticides almost inhibited the expression of all tested GST, CarE, and P450 genes in contact bioassays but induced the transcriptional levels of these genes in dietary bioassays. Silencing of NlGSTD2 expression had the greatest effect on BPH sensitivity to nitenpyram in contact test and imidacloprid in dietary test. The sensitivities of BPH to insecticide increased the most in the contact test was etofenprox after silencing of NlCE, while the dietary test was nitenpyram. Knockdown of NlCYP408A1 resulted in BPH sensitivities to insecticide increasing the most in the contact test was nitenpyram, while the dietary test was imidacloprid. Taken together, these findings reveal that NlGSTD2, NlCE, and NlCYP408A1 play an indispensable role in the detoxification of the contact and ingestion toxicities of different types of insecticides to BPH, which is of great significance for the development of new strategies for the sucking pest control.

Optimization of polyethylene terephthalate biodegradation using a self-assembled multi-enzyme cascade strategy.

Although many efforts have been devoted to the modification of polyethylene terephthalate (PET) hydrolases for improving the efficiency of PET degradation, the catalytic performance of these enzymes at near-ambient temperatures remains a challenge. Herein, a multi-enzyme cascade system (PT-EC) was developed and validated by assembling three well-developed PETases, PETaseEHA, Fast-PETase, and Z1-PETase, respectively, together with carboxylesterase TfCa, and hydrophobic binding module CBM3a using scaffold proteins. The resulting PT-ECEHA, PT-ECFPE, PT-ECZPE all demonstrated outstanding PET degradation efficacy. Notably, PT-ECEHA exhibited a 16.5-fold increase in product release compared to PETaseEHA, and PT-ECZPE yielded the highest amount of product. Subsequently, PT-ECs were displayed on the surface of Escherichia coli, respectively, and their degradation efficiency toward three PET types was investigated. The displayed PT-ECEHA exhibited a 20-fold increase in degradation efficiency with PET film compared to the surface-displayed PETaseEHA. Remarkably, an almost linear increase in product release was observed for the displayed PT-ECZPE over a one-week degradation period, reaching 11.56 ± 0.64 mM after 7 days. TfCaI69W/L281Y evolved using a docking-based virtual screening strategy showed a further 2.5-fold increase in the product release of PET degradation. Collectively, these advantages of PT-EC demonstrated the potential of a multi-enzyme cascade system for PET bio-cycling.

Characterization of a novel carboxylesterase from Streptomyces lividans TK24 and site-directed mutagenesis for its thermostability.

As an industrial enzyme that catalyzes the formation and cleavage of ester bonds, carboxylesterase has attracted attention in fine chemistry, pharmaceutical, biological energy and bioremediation fields. However, the weak thermostability limits their further developments in industrial applications. In this work, a novel carboxylesterase (EstF) from Streptomyces lividans TK24, belonging to family XVII, was acquired by successfully heterologous expressed and biochemically identified. The EstF exhibited optimal activity at 55 °C, pH 9.0 and excellent catalytic performances (Km = 0.263 mM, kcat/Km = 562.3 s-1 mM-1 for p-nitrophenyl acetate (pNPA2) hydrolysis). Besides, the EstF presented exceptionally high thermostability with a half-life of 387.23 h at 55 °C and 2.86 h at 100 °C. Furthermore, the EstF was modified to obtain EstFP144G using the site-directed mutation technique to investigate the effect of single glycine on thermostability. Remarkably, the mutant EstFP144G displayed a 5.10-fold increase of half-life at 100 °C versus wild-type without affecting catalytic performance. Structural analysis implied that the glycine introduction could release a steric strain and induce cooperative effects between distal residues to increase the thermostability. Therefore, the thermostable EstF and EstFP144G with prominently catalytic characteristics have potential industrial applications and the introduction of a single glycine strategy opens up alternative avenues for the thermostability engineering of other enzymes.

Lowering pH optimum of activity of SshEstI, a slightly alkaliphilic archaeal esterase of the hormone-sensitive lipase family.

SshEstI, a carboxylesterase from the thermoacidophilic archaeon Saccharolobus shibatae, is a member of the hormone-sensitive lipase family that displays slightly alkaliphilic activity with an optimum activity at pH 8.0. In this study, three distinct strategies were explored to confer acidophilic properties to SshEstI. The first strategy involved engineering the oxyanion hole by replacing Gly81 with serine or aspartic acid. The G81S mutant showed optimum activity at pH 7.0, whereas the aspartic acid mutant (G81D) rendered the enzyme slightly acidophilic with optimum activity observed at pH 6.0; however, kcat and kcat/Km values were reduced by these substitutions. The second strategy involved examining the effects of surfactant additives on the pH-activity profiles of SshEstI. The results showed that cetyltrimethylammonium bromide (CTAB) enhanced wild-type enzyme (WT) activity at acidic pH values. In the presence of 0.1 mM CTAB, G81S and G81D were acidophilic enzymes with optimum activity at pH 6.0 and 4.0, respectively, although their enzyme activities were low. The third strategy involved engineering the active site to resemble that of kumamolisin-As (kuma-As), an acidophilic peptidase of the sedolisin family. The catalytic triad of kuma-As was exchanged into SshEstI using site-directed mutagenesis. X-ray crystallographic analysis of the mutants (H274D and H274E) revealed that the potential hydrogen donor-acceptor distances around the active site of WT were fully maintained in these mutants. However, these mutants were inactive at pH 4-8.

Cloning, Expression, Characterization and Immobilization of a Recombinant Carboxylesterase from the Halophilic Archaeon, Halobacterium salinarum NCR-1.

Only a few halophilic archaea producing carboxylesterases have been reported. The limited research on biocatalytic characteristics of archaeal esterases is primarily due to their very low production in native organisms. A gene encoding carboxylesterase from Halobacterium salinarum NRC-1 was cloned and successfully expressed in Haloferax volcanii. The recombinant carboxylesterase (rHsEst) was purified by affinity chromatography with a yield of 81%, and its molecular weight was estimated by SDS-PAGE (33 kDa). The best kinetic parameters of rHsEst were achieved using p-nitrophenyl valerate as substrate (KM = 78 µM, kcat = 0.67 s-1). rHsEst exhibited great stability to most metal ions tested and some solvents (diethyl ether, n-hexane, n-heptane). Purified rHsEst was effectively immobilized using Celite 545. Esterase activities of rHsEst were confirmed by substrate specificity studies. The presence of a serine residue in rHsEst active site was revealed through inhibition with PMSF. The pH for optimal activity of free rHsEst was 8, while for immobilized rHsEst, maximal activity was at a pH range between 8 to 10. Immobilization of rHsEst increased its thermostability, halophilicity and protection against inhibitors such as EDTA, BME and PMSF. Remarkably, immobilized rHsEst was stable and active in NaCl concentrations as high as 5M. These biochemical characteristics of immobilized rHsEst reveal its potential as a biocatalyst for industrial applications.

Assessing the impact of antiviral drugs commonly utilized during the COVID-19 pandemic on the embryonic development of Xenopus laevis.

The antiviral drugs favipiravir and oseltamivir are widely used to treat viral infections, including coronavirus 2019 (COVID-19), and their levels are expected to increase in the aquatic environment. In this study, the potential toxic and teratogenic effects of these drugs were evaluated using the frog embryo teratogenesis assay Xenopus (FETAX). In addition, glutathione S-transferase (GST), glutathione reductase (GR), catalase, carboxylesterase (CaE), and acetylcholinesterase (AChE) enzyme activities and malondialdehyde levels were measured as biochemical markers in embryos and tadpoles for comparative assessment of the sublethal effects of the test compounds. Prior to embryo exposure, drug concentrations in the exposure medium were measured with high-performance liquid chromatography. The 96-h median lethal concentration (LC50) was 137.9 and 32.3 mg/L for favipiravir and oseltamivir, respectively. The teratogenic index for favipiravir was 4.67. Both favipiravir and oseltamivir inhibited GR, CaE, and AChE activities in embryos, while favipiravir increased the GST and CaE activities in tadpoles. In conclusion, favipiravir, for which teratogenicity data are available in mammalian test organisms and human teratogenicity is controversial, inhibited Xenopus laevis embryo development and was teratogenic. In addition, sublethal concentrations of both drugs altered the biochemical responses in embryos and tadpoles, with differences between the developmental stages.

Construction of a novel aminofluorene-based ratiometric near-infrared fluorescence probe for detecting carboxylesterase activity in living cells.

Herein, we constructed a novel aminofluorene-based fluorescence probe (FEN-CE) for the detection of carboxylesterase (CE) in living cells by a ratiometric near-infrared (NIR) fluorescence signal. FEN-CE with NIR emission (650 nm) could be hydrolyzed specifically by CE and transformed to FENH with the release of the self-immolative group, which exhibited a red-shifted emission peak of 680 nm. In addition, FEN-CE showed high selectivity for CE and was successfully used in the detection of CE activity in living cells through its ratiometric NIR fluorescence signals.

ABCB1 attenuates brain exposure to the KRASG12C inhibitor opnurasib whereas binding to mouse carboxylesterase 1c influences its plasma exposure.

Opnurasib (JDQ443) is a newly developed oral KRASG12C inhibitor, with a binding mechanism distinct from the registered KRASG12C inhibitors sotorasib and adagrasib. Phase I and II clinical trials for opnurasib in NSCLC are ongoing. We evaluated the pharmacokinetic roles of the ABCB1 (P-gp/MDR1) and ABCG2 (BCRP) efflux and OATP1 influx transporters, and of the metabolizing enzymes CYP3A and CES1 in plasma and tissue disposition of oral opnurasib, using genetically modified cell lines and mouse models. In vitro, opnurasib was potently transported by human (h)ABCB1 and slightly by mouse (m)Abcg2. In Abcb1a/b- and Abcb1a/b;Abcg2-deficient mice, a significant ∼100-fold increase in brain-to-plasma ratios was observed. Brain penetration was unchanged in Abcg2-/- mice. ABCB1 activity in the blood-brain barrier may therefore potentially limit the efficacy of opnurasib against brain metastases. The Abcb1a/b transporter activity could be almost completely reversed by co-administration of elacridar, a dual ABCB1/ABCG2 inhibitor, increasing the brain penetration without any behavioral or postural signs of acute CNS-related toxicity. No significant pharmacokinetic roles of the OATP1 transporters were observed. Transgenic human CYP3A4 did not substantially affect the plasma exposure of opnurasib, indicating that opnurasib is likely not a sensitive CYP3A4 substrate. Interestingly, Ces1-/- mice showed a 4-fold lower opnurasib plasma exposure compared to wild-type mice, whereas no strong effect was seen on the tissue distribution. Plasma Ces1c therefore likely binds opnurasib, increasing its retention in plasma. The obtained pharmacokinetic insights may be useful for further optimization of the clinical efficacy and safety of opnurasib, and might reveal potential drug-drug interaction risks.

Preliminary Study on the Pathogenic Mechanism of Jujube Flower Disease in Honeybees (Apis mellifera ligustica) Based on Midgut Transcriptomics.

Honeybees are prone to poisoning, also known as jujube flower disease, after collecting nectar from jujube flowers, resulting in the tumultuous demise of foragers. The prevalence of jujube flower disease has become one of the main factors affecting the development of the jujube and beekeeping industries in Northern China. However, the pathogenic mechanisms underlying jujube flower disease in honeybees are poorly understood. Herein, we first conducted morphological observations of the midgut using HE-staining and found that jujube flower disease-affected honeybees displayed midgut damage with peritrophic membrane detachment. Jujube flower disease was found to increase the activity of chitinase and carboxylesterase (CarE) and decrease the activity of superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), and the content of CYP450 in the honeybee midgut. Transcriptomic data identified 119 differentially expressed genes in the midgut of diseased and healthy honeybees, including CYP6a13, CYP6a17, CYP304a1, CYP6a14, AADC, and AGXT2, which are associated with oxidoreductase activity and vitamin binding. In summary, collecting jujube flower nectar could reduce antioxidant and detoxification capacities of the honeybee midgut and, in more severe cases, damage the intestinal structure, suggesting that intestinal damage might be the main cause of honeybee death due to jujube nectar. This study provides new insights into the pathogenesis of jujube flower disease in honeybees.

Carboxylesterase Activatable Molecular Probe for Personalized Treatment Guidance by Analyte-Induced Molecular Transformation.

Accurate visualization of tumor microenvironment is of great significance for personalized medicine. Here, we develop a near-infrared (NIR) fluorescence/photoacoustic (FL/PA) dual-mode molecular probe (denoted as NIR-CE) for distinguishing tumors based on carboxylesterase (CE) level by an analyte-induced molecular transformation (AIMT) strategy. The recognition moiety for CE activity is the acetyl unit of NIR-CE, generating the pre-product, NIR-CE-OH, which undergoes spontaneous hydrogen atom exchange between the nitrogen atoms in the indole group and the phenol hydroxyl group, eventually transforming into NIR-CE-H. In cellular experiments and in vivo blind studies, the human hepatoma cells and tumors with high level of CE were successfully distinguished by both NIR FL and PA imaging. Our findings provide a new molecular imaging strategy for personalized treatment guidance.

Biochemical and molecular-level effects of co-exposure to chlorpyrifos and lambda-cyhalothrin on the earthworm (Eisenia fetida).

Farmland soil organisms frequently encounter pesticide mixtures presented in their living environment. However, the underlying toxic mechanisms employed by soil animals to cope with such combined pollution have yet to be explored. This investigation aimed to reveal the changes in cellular and mRNA levels under chlorpyrifos (CPF) and lambda-cyhalothrin (LCT) co-exposures in earthworms (Eisenia fetida). Results exhibited that the combination of CPF and LCT triggered an acute synergistic influence on the animals. Most exposures resulted in significant alterations in the activities of total superoxide dismutase (T-SOD), copper/zinc superoxide dismutase (Cu/Zn-SOD), caspase 3, and carboxylesterase (CarE) compared to the basal level. Moreover, when exposed to chemical mixtures, the transcription levels of four genes [heat shock protein 70 (hsp70), gst, sod, and calreticulin (crt)] also displayed more pronounced changes compared with their individual exposures. These changes in determined parameters indicated the occurrence of oxidative stress, cell death, detoxification dysfunction, and endoplasmic reticulum damage after co-exposure to CPF and LCT in E. fetida. The comprehensive examination of mixture toxicities of CPF and LCT at different endpoints would help to understand the overall toxicity they cause to soil invertebrates. The augmented deleterious effect of these pesticides in a mixture suggested that mixture toxicity assessment was necessary for the safety evaluation and application of pesticide mixtures.

Design, synthesis, and evaluation of a carboxylesterase detection probe with therapeutic effects.

In this study, a lysosomal targeting fluorescent probe recognition on CEs was designed and synthesized. The obtained probe BF2-cur-Mor demonstrated excellent selectivity, sensitivity, pH-independence, and enzyme affinity towards CEs within 5 min. BF2-cur-Mor could enable recognition of intracellular CEs and elucidate that the CEs content of different cancer cells follows the rule of HepG2 > HCT-116 > A549 > HeLa, and the CEs expression level of hepatoma cancer cells far exceeds that of normal hepatic cells, being in good agreement with the previous reports. The ability of BF2-cur-Mor to monitor CEs in vivo was confirmed by zebrafish experiment. BF2-cur-Mor exhibits some pharmacological activity in that it can induce apoptosis in hepatocellular carcinoma cells but is weaker in normal hepatocyte cells, being expected to be a potential "diagnostic and therapeutic integration" tool for the clinical diagnosis of CEs-related diseases.