Carboxylesterase Activity Research Articles

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

IntroductionSemiaphis 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.MethodsThe 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.ResultsThe 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.ConclusionThe 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.

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.

Impacts of an organophosphate pesticide and water restriction on physiology and immunity in the passerine Zonotrichia capensis.

Climate change, specifically rising temperatures and increased frequency of droughts will increase the level of exposure of organisms to chemical pollution. Notably, the impact of increased frequency and duration of drought events and subsequent dehydration on pesticide toxicity remains largely unknown. We evaluated the combined effects of exposure to the pesticide Chlorpyrifos (CPF) and water restriction (WR) on the enzymatic activities of three plasma esterases (acetylcholinesterase, butyrylcholinesterase and carboxylesterase), basal metabolic rate (BMR), leukocyte profile (proportion of heterophils to lymphocytes; H:L ratio), and bactericidal capacity of plasma in the rufous-collared sparrow (Zonotrichia capensis), a common passerine bird in Chile. The activity of the enzyme carboxylesterase decreased in birds exposed only to CPF and birds exposed to both the CPF and WR. In the group exposed to both stressors, the butyrylcholinesterase activity was also reduced. The BMR exhibited an increase in both groups exposed to CPF, with a higher rise observed in the group exposed to both CPF and WR, while the group subjected to WR showed no change. The bactericidal capacity of the plasma decreased significantly in birds exposed to CPF and in those exposed to both the pesticide and WR, while a marginal effect was observed in the group only subjected to WR. The H:L ratio increased in all groups, with the most pronounced effect in birds exposed to both stressors. These results suggest a shift in the energy budget of Z. capensis, favoring the detoxification of the pesticide through esterase activities, at the expense of reduced immunocompetence.

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.

Integrated microbiome and metabolomic analysis of Spodoptera litura under Metarhizium flavoviride qc1401 stress.

Metarhizium spp. have emerged as an alternative to chemical pesticides for protecting crops from insect pest. Here, we investigated midgut microbial community and metabolites of Spodoptera litura at three different timepoints after infection with Metarhizium flavoviride. The innate immune system of S. litura was activated with levels of polyphenol oxidase, carboxylesterase, multifunctional oxidase, and glutathione S-transferase activity significantly increasing. Exposure to the fungal pathogen also altered bacterial abundance and diversity in host's midgut, and these changes varied depending on the time elapsed since exposure. We identified more operational taxonomic units in the treated samples as compared to the control samples at all tested time points. A total of 372 metabolites were identified, and 88, 149, and 142 differentially accumulated metabolites (DAMs) were identified between the treatment and control groups at 3 timepoints after treatment, respectively. Based on the changes of DAMs in response to M. flavoviride infection at different timepoints and significantly enriched KEGG pathways, we speculated that "tyrosine metabolism," "galactose metabolism," "ATP-binding cassette transporters," "neuroactive ligand-receptor interaction," "purine metabolism," "arginine and proline metabolism," "beta-alanine metabolism," "lysosome," and "carbon metabolism" may participate in the metabolic-level defense response. An integrated pathway-level analysis of the 16S-rDNA and metabolomic data illustrated the connections and interdependencies between the metabolic responses of S. litura and the midgut microorganisms to M. flavoviride infection. This work emphasizes the value of integrated analyses of insect-pathogen interactions, provides a framework for future studies of critical microorganisms and metabolic determinants of these interactions, establishes a theoretical basis for the sustainable use of M. flavoviride.

Effects of injudicious use of spirotetramat on Encarsia formosa's ability to control Bemisia tabaci

The excessive and frequent use of insecticides has led to serious problems with insecticide residues, impacting nontarget organisms such as the parasitoid Encarsia formosa. This study examined the growth, development, and enzyme activity of E. formosa exposed to spirotetramat at LC10, LC30, and LC50. The regression equation for the toxicity of spirotetramat toward E. formosa was Y = 5.25X–11.07. After exposure to spirotetramat, the survival rates of E. formosa sharply decreased, which occurred earlier than those in the control batch. Although the maximum daily parasitism quantity of E. formosa increased and the average parasitism number, enumerated from the 1st to the 5th day, was 53.97 after being exposed to spirotetramat at LC10, the life span of its F1 generation adults was only 8.47 days, which was significantly shorter than that in the control batch. After being exposed to spirotetramat at LC50, the average parasitism number of E. formosa was 63.30, and the developmental time of its F1 generation, enumerated from the 1st to the 5th day after exposure to spirotetramat, was significantly longer than that of the control batch. The activities of mixed function oxidase, acetylcholinesterase, carboxylesterase, and catalase increased significantly, and the rate of increase in enzyme activity was directly proportional to the increase in the concentration of spirotetramat. These results revealed that the parasitic ability of E. formosa decreased after exposure to spirotetramat at LC10, LC30, and LC50. This leads to a change in parasitoid control of pests, revealing the potential environmental threat of insecticide residues to nontarget organisms.

Functional analysis of novel cystatins from Haemaphysalis doenitzi and evaluation of their roles in cypermethrin and λ-cyhalothrin resistance

Currently, the primary strategy for tick control relies on chemical agents. Pyrethrins, which are botanically derived compounds, have demonstrated efficacy in controlling ticks without posing a risk to human or animal health. However, research into pyrethrins' metabolic mechanisms remains sparse. Cystatin, as a reversible binding inhibitor of cysteine protease, may be involved in the initiation of pyrethrin detoxification of Haemaphysalis doenitzi. In this study, two novel cystatins were cloned, HDcyst-3 and HDcyst-4, the relative expression of which was highest in the Malpighian tubules compared with the tick midguts, salivary glands, and ovaries. Prokaryotic expression and in vitro studies revealed that cystatins effectively inhibit the enzymatic activities of cathepsins B and S. RNAi results showed that the reduction of cystatins significantly decreased the engorgement weight, egg mass weight, and egg hatching rate of adult female ticks, and prolonged feeding time by two days. The control rate of rHDcyst-3 and rHDcyst-4 protein vaccination against female adults were 55.9% and 63.2%, respectively. In addition, the tick immersion test showed that cypermethrin and λ-cyhalothrin had significant acaricidal effects against adult unfed H. doenitzi. The qPCR result indicated that compared with the control group, the expression of HDcyst-3 and HDcyst-4 was markedly decreased in the sublethal cypermethrin and λ-cyhalothrin group at LC50. Enzyme activity showed that cypermethrin and λ-cyhalothrin could significantly induce the activities of glutathione S-transferase (GST), carboxylesterase (CarE), and acetylcholinesterase (AchE). The aforementioned results provided indirect evidence that cystatin plays an important role in pyrethrin detoxification and provides a theoretical basis for future acaricide experiments and pest management.

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.

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

AbstractAccurate 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.