Degradation and detection of organophosphorus pesticides based on peptides and MXene-peptide composite materials.

Safety problems caused by organophosphorus pesticide (OP) residues are constantly occurring, so the development of new methods for the degradation and detection of OPs is of great scientific significance. In the present study, ß-sheet peptides and ß-hairpin peptides for catalyzing the hydrolysis of OPs were designed and synthesized. The peptide sequences with the highest hydrolytic activity (EHSGGVTVDPPLTVEHSAG) were screened by investigating the effect of the location of the active sites of the peptide and the peptide's structure on the degradation of OPs. In addition, the relationship between the peptides' conformation and hydrolytic activity was further analyzed based on density functional theory calculations. The noncovalent interactions of the peptides with the OPs and the electrostatic potential on the molecular surface and molecular docking properties were also investigated. It was found that peptides with approximate active amino acids consisting of the catalytic triad and with the hairpin structure had enhanced hydrolytic activity toward the hydrolysis of OPs. To develop an electrochemical sensor technique to detect OPs, the conductive MXene (Ti3C2) material was first immobilized with a caffeic acid monolayer via enediol-metal complex chemistry and then bound with the ß-hairpin peptide (EHSGGVTVDPPLTVEHSAG) via carboxy-amine condensation chemistry between the -COOH of caffeic acid and the -NH2 of the peptide to prepare a MXene-peptide composite. Then, the prepared composite was modified on the surface of a glassy carbon electrode to construct an electrochemical sensor for the detection of OPs. The developed technique could be used to monitor OPs within 15 min with a two orders of linear working range and with a detection limit of 0.15 µM. Meanwhile, the sensor showed good reliability for the detection of OPs in real vegetables.

Degradation of Di (2-ethylhexyl) phthalic acid plasticizer in baijiu by a foam titanium flow reactor attached with hairpin-like structured peptide enzyme mimics.

Because of the significant environmental and health hazards imposed by di(2-ethylhexyl) phthalate (DEHP), a common plasticizer, developing safe and green techniques to degrade DEHP plasticizer is of huge scientific significance. It has been observed that environmental contamination of DEHP may also induce serious food safety problems because crops raised in plasticizers contaminated soils would transfer the plasticizer into foods, such as Baijiu. Additionally, when plastic packaging or vessels are used during Baijiu fermentation and processing, plasticizer compounds frequently migrate and contaminate the product. In this study, hairpin-like structured peptides with catalytically active sites containing serine, histidine and aspartic acid were found to degrade DEHP. Furthermore, after incorporating caffeic acid molecules at the N-terminus, the peptides could be attached onto foam titanium (Ti) surfaces via enediol-metal interactions to create an enzyme-mimicking flow reactor for the degradation of DEHP in Baijiu. The structure and catalytic activity of peptides, their interaction with DEHP substrate and the hydrolysis mechanism of DEHP were discussed in this work. The stability and reusability of the peptide-modified foam Ti flow reactor were also investigated. This approach provides an effective technique for the degradation of plasticizer compounds.

Three LHPP gene-targeting co-expressed microRNAs (microRNA-765, microRNA-21, and microRNA-144) promote proliferation, epithelial-mesenchymal transition, invasion, and are independent prognostic biomarkers in renal cell carcinomas patients.

BACKGROUND: Renal cell carcinoma (RCC) is one of the highly malignant tumors in the world. Global Cancer Statistics 2020 estimated that there were 179,368 deaths from kidney tumors. Therefore, exploring the prognostic biomarkers of RCC is of great significance for RCC patients. This study aims to explore the potential mechanism and prognostic value of phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) gene-targeting co-expression microRNAs in RCC patients. METHODS: A total of 60 RCC patients were included. Quantitative real-time PCR (qRT-PCR), western blotting, and immunohistochemistry were used for LHPP, microRNA-765, microRNA-21, and microRNA-144 levels evaluation. Cell Counting Kit-8 assay, dual-luciferase reporter gene assay, invasion assay, and RNA fluorescence in situ hybridization were used for functional analyses. RESULTS: Compared with adjacent tissues, LHPP levels in cancer tissues were significantly increased (p < .001). Herein, we confirmed that microRNA-765, microRNA-21, and microRNA-144 were direct biological targets of LHPP. MicroRNA-765 (r = -0.570, p < 0.001), microRNA-21 (r = -0.495, p < .001), and microRNA-144 (r = -0.463, p < .001) expression levels were negatively correlated with LHPP expression levels. The high expression levels of microRNA-765, microRNA-21, and microRNA-144 in RCC tissues were associated with poor differentiation, recurrence, and poor prognosis (p < .05). In vitro, microRNA-765, microRNA-21, and microRNA-144 act as oncogenes to promote proliferation, invasion, and epithelial-mesenchymal transition (EMT) through targeting LHPP. CONCLUSIONS: MicroRNA-765, microRNA-21, and microRNA-144 are independent risk biomarkers for RCC patients. Inhibiting the expression levels of microRNA-765, microRNA-21, and microRNA-144 can reduce the proliferation, EMT, and invasion of RCC cells. Therefore, the above three microRNAs are expected to become molecular biomarkers for RCC therapy.