Transport and Environmental Risks of Propachlor Within the Soil–Plant–Water Phase as Affected by Dissolved Organic Matter as a Nonionic Surfactant

Propachlor is a widely used acylaniline herbicide for weeding annual gramineous and dicot plants in farmland. As a toxic agricultural chemical, it is overused in crop production and has become one of the most serious environmental pollutants. Yet, understanding the impact of environmental factors on its behavior in farmland soils is critically important for healthy crop production and food safety. In this study, we characterized the effect of dissolved organic matter (DOM) extracted from rice straw on the mobility behavior of propachlor in farmland soil using comprehensive approaches such as the batch equilibrium experiment, soil thin-layer chromatography, soil column leaching, and wheat bioaccumulation with Triton X-100 (TX-100) as a reference surfactant. The application of DOM at 60 and 120 mg DOC L–1 and TX-100 at 96, 192, and 288 mg L–1 reduced the sorption and increased the desorption of propachlor in soil. Freundlich constant Kf values (sorption) of propachlor declined with the expansion of DOM and TX-100 concentrations. The addition of DOM and TX-100 increased the mobility of propachlor and the total concentration of propachlor in the leachate of soil columns. The retention factors (Rf) were evaluated in the soil thin-layer chromatography as 0.741 and 0.772 (for DOM) and 0.731, 0.763, and 0.791 (for TX-100), all of which were greater than the control (0.710) under the treatment. The application of DOM or TX-100 reduced root growth (biomass) and increased bioaccumulation of propachlor in the roots and shoots of wheat. The outcome of the study can provide important references for the rational use of propachlor and help agronomic management to minimize pesticide contamination in realistic crop production

MicroRNA-Responsive Cancer Cell Imaging and Therapy with Functionalized Gold Nanoprobe

Integration of cancer cell imaging and therapy is critical to enhance the theranostic efficacy and prevent under- or overtreatment. Here, a multifunctional gold nanoprobe is designed for simultaneous miRNA-responsive fluorescence imaging and therapeutic monitoring of cancer. By assembling with folic acid as the targeted moiety and a dye-labeled molecular beacon (MB) as the recognition element and signal switch, the gold nanoprobe is folate receptor-targeted delivered into the cancer cells, and the fluorescence is lighted with the unfolding of MB by intracellular microRNA (miRNA), resulting in an efficient method for imaging and detecting nucleic acid. The average quantity of miRNA-21 is measured to be 1.68 pg in a single HeLa cell. Upon the near-infrared irradiation at 808 nm, the real-time monitoring and assessing of photothermal therapeutic efficacy is achieved from the further enhanced fluorescence of the dye-labeled MB, caused by the high photothermal transformation efficiency of the gold nanocarrier to unwind the remaining folded MB and depart the dye from the nanocarrier. The fluorescence monitoring is also feasible for applications in vivo. This work provides a simple but powerful protocol with great potential in cancer imaging, therapy, and therapeutic monitoring

Multifunctional Metal–Organic Framework Nanoprobe for Cathepsin B‑Activated Cancer Cell Imaging and Chemo-Photodynamic Therapy

Integration of a photodynamic therapy platform with a drug-delivery system in a porous structure is an urgent challenge for enhanced anticancer therapy. Here, an amino-functionalized metal–organic framework (MOF), which is useful as efficient delivery vehicle for drugs and provides the −NH2 group for postsynthetic modification, is chosen and well-designed for cell imaging and chemo-photodynamic therapy. The multifunctional MOF nanoprobe was first assembled with camptothecine drug via noncovalent encapsulation and then bound with folic acid as the targeted element and chlorine e6 (Ce6)-labeled CaB substrate peptide as the recognition moiety and signal switch. The designed MOF probe can realize cathepsin B-activated cancer cell imaging and chemo-photodynamic dual-therapy combining Ce6 as the photosensitizer and the camptothecine drug. Compared with the individual treatment, the dual-functional nanoprobe presents an enhanced treatment efficiency in terms of the time of chemotherapy, laser power, and irradiation time of the photodynamic therapy, which has been confirmed in cancer cells and in vivo assays. This work presents a significant example of the MOF nanoprobe as an intracellular switch and shows great potential in cancer cell targeted imaging and multiple therapies

Expression of <i>CYP76C6</i> Facilitates Isoproturon Metabolism and Detoxification in Rice

Agricultural chemical residues in farmland and crops is one of the serious public issues that constantly threatens crop production, food security, and human health. Understanding their decay mechanism in crops for accelerating their degradative metabolism is important. In this study, a rice uncharacterized cytochrome P450 gene encoding CYP76C6 was functionally identified in rice exposed to isoproturon (IPU). To verify the role of CYP76C6 in rice resistance to IPU toxicity, CYP76C6 overexpression (OEs) and knockout mutant rice by CRISPR/Cas9 were generated through genetic transformation and gene-editing technologies. Assessment of growth and physiological responses revealed that the growth of OE lines was improved, the IPU-induced cellular damage was attenuated, and IPU accumulation was significantly repressed, whereas the Cas9 lines displayed a contrasting phenotype compared to the wild-type. Both relative contents of IPU metabolites and conjugates in OE lines were reduced and those in Cas9 line were increased, suggesting that CYP76C6 plays a critical role in IPU degradation. Our study unveils a new regulator, together with its mechanism for IPU decay in rice crops, which will be used in reality to reduce environmental risks in food safety and human health

Multiple Metabolism Pathways of Bentazone Potentially Regulated by Metabolic Enzymes in Rice

Bentazone (BNTZ) is a selective and efficient herbicide used in crop production worldwide. However, the persistence of BNTZ residues in the environment has led to their increasing accumulation in farmland and crops, posing a high risk to human health. To evaluate its impact on crop growth and environmental safety, a comprehensive study was conducted on BNTZ toxicity, metabolic mechanism, and resultant pathways in rice. The rice growth was compromised to the treatment with BNTZ at 0.2–0.8 mg/L (529.95–1060.05 g a.i./ha), while the activities of enzymes including SOD, POD, CAT, GST, GT, and CYP450 were elevated under BNTZ stress. A genome-wide RNA-sequencing (RNA-Seq) was performed to dissect the variation of transcriptomes and metabolic mechanisms in rice exposed to BNTZ. The degradative pathways of BNTZ in rice are involved in glycosylation, hydrolysis, acetylation, and conjugation processes catalyzed by the enzymes. Our data provided evidence that helps understand the BNTZ metabolic and detoxic mechanisms

Minimized Atrazine Risks to Crop Security and Its Residue in the Environment by a Rice Methyltransferase as a Regulation Factor

Atrazine (ATZ) is an agricultural pesticide for controlling field weeds. ATZ accumulates in many crops, posing high risks to crop production and food safety. Characterizing one of the novel rice MT genes named Oryza sativa atrazine-responsive methyltransferase (OsARM) showed that the expression of OsARM was associated with DNA demethylation (hypomethylation) in its promoter region. The enhancement of OsARM expression was manifested by the attenuated symptoms of ATZ toxicity including better growth and lower ATZ accumulation in plants. The promoted capacity of detoxification was confirmed by transgenic rice overexpression OsARM lines and also functionally proved by CRISPR-Cas9 knockout mutants. The transgenic lines accumulate more ATZ metabolites in rice and lower concentrations in the growth environment, pointing out that ATZ metabolism or degradation can be intensified. The ATZ-induced DNA demethylation is an important hallmark representing the epigenetic mechanism, which is required for the extra OsARM expression to facilitate ATZ disappearance in rice and the environment

Target-Responsive Metal–Organic Framework Nanosystem with Synergetic Sensitive Detection and Controllable Degradation against the Pesticide Triazophos in Contaminated Samples for Environment Assessment and Food Safety

Developing sensitive practical sensors for monitoring pesticide residues in edible foods and environmental samples is vital for food safety and environmental protection. Enzyme-inhibited biosensors offer effective alternative sensing strategies by using the inherent characteristics of pesticides. To further improve the degradation function of pesticide sensors, here, a target-triggered porphyrin metal–organic framework (MOF)-based nanosystem was designed with the synergetic bifunction of sensitive detection and controllable degradation of the triazophos pesticide. As a result of triazophos-inhibited glutathione consumption, the MOF collapsed and released the ligand porphyrin, leading to the recovery of fluorescence and photosensitization of the free porphyrin. The fluorescence recovery resulted in a sensitive detection limit of 0.6 ng mL–1 for triazophos, which was also applied for the determination of contaminated samples and bioaccumulation in rice. Furthermore, the target-activated photocatalytic ability of porphyrin endowed the system with the ability to effectively generate reactive oxygen species for degrading triazophos with a removal rate of ∼85%, achieving eco-friendly synergetic detection and photodegradation in a controllable way. Therefore, the intelligent multifunctional MOF system demonstrated the potential of programmable systems for jointly controllable tracking and elimination of pesticide residues in the environment and opened a new avenue for designing a precise mechanism for stimulus-triggered degradation of pesticide residues accompanied by sensitive detection for environmental friendliness and food safety

Nonenzymatic Target-Driven DNA Nanomachine for Monitoring Malathion Contamination in Living Cells and Bioaccumulation in Foods

Intensive applications of toxic malathion pesticides bring a vital threat to the environment and health. Hence, a credible and sensitive strategy is urgently needed for the respective detection of malathion. In this work, an aptamer-based nonenzymatic autonomous DNA walking machine was fabricated for monitoring trace malathion contamination in cells and foods. Along with the machine walking driven by malathion-triggered reaction entropy, multiple fluorescent signal outputs were thermodynamically generated for signal amplification. The proposed stable DNA nanomachine achieved satisfactory results with a detection limit of 81.9 pg L–1 for testing malathion, which could be applied to actual samples including apple juice, paddy water, and paddy soil. Furthermore, the high stability, sensitivity, and biocompatibility of the nanomachine enabled monitoring of the malathion contamination in living cells and bioaccumulation in lettuce without additional purification. Consequently, with these excellent performances, it is strongly anticipated that the DNA walking machine has tremendous potential to be extended to general platforms against pesticides to avoid malathion-contaminated agricultural production for environmental safety and human health