Recently, urinary tract infection (UTI) triggered by bacteria carrying pan-drug-resistant genes, including carbapenem resistance gene bla_NDM and bla_KPC, colistin resistance gene mcr-1, and tet(X) for tigecycline resistance, have been reported, posing a serious challenge to the treatment of clinical UTI. Therefore, point-of-care (POC) detection of these genes in UTI samples without the need for pre-culturing is urgently needed. Based on PEG 200-enhanced recombinase polymerase amplification (RPA) and a refined Chelex-100 lysis method with HRP-catalyzed lateral flow immunoassay (LFIA), we developed an MCL-PRPA-HLFIA cascade assay system for detecting these genes in UTI samples. The refined Chelex-100 lysis method extracts target DNA from UTI samples in 20 min without high-speed centrifugation or pre-incubation of urine samples. Following optimization, the cascade detection system achieved an LOD of 10² CFU/mL with satisfactory specificity and could detect these genes in both simulated and actual UTI samples. It takes less than an hour to complete the process without the use of high-speed centrifuges or other specialized equipment, such as PCR amplifiers. The MCL-PRPA-HLFIA cascade assay system provides new ideas for the construction of rapid detection methods for pan-drug-resistant genes in clinical UTI samples and provides the necessary medication guidance for UTI treatment.

The binding interactions between okadaic acid (OA) aptamers and OA molecules are crucial for developing effective detection methods. This study aims to identify the recognition site and establish a reliable detection protocol through computational simulations and experimental validations. After determining the target sequence (OA-2), molecular docking simulations using Sybyl-X and H-dock were conducted to predict the binding affinity and interaction sites of OA aptamers with their targets. These predictions were subsequently validated through experiments based on the Förster resonance energy transfer (FRET) principle. The combined approach not only confirmed the computational predictions, identifying the “major region” as the recognition basis of OA-2, but also provided deeper insights into the binding mechanisms. Subsequently, a classical AuNPs-aptamer colorimetric detection method was established based on the OA-2 sequence and applied to the detection of real shellfish samples, achieving a limit of quantification (LOQ) of 5.0 μg kg⁻¹. The recoveries of OA in spiked samples ranged from 79.0% to 122.9%, with a relative standard deviation (RSD) of less than 14.7%. The results of this study contribute to the development of robust detection methods for OA aptamer–target interactions, enhancing the potential for practical applications in toxin detection and monitoring.

Highland barley (hulless barley, Hordeum vulgare L. var. nudum) flour is a nutritionally dense staple of the Qinghai–Tibet Plateau, but its high contents of unsaturated lipids and active endogenous enzymes render it highly susceptible to storage deterioration. Natural polysaccharides have been proposed as green preservatives, yet the dose-dependent effects of Lycium barbarum polysaccharide (LBP) on the storage quality of cereal flours and the underlying lipid-level mechanisms remain unclear. Here, highland barley flour (cv. Kunlun-15) was blended with LBP at 0.2%, 1.0% and 2.0% (w/w) stored in sealed bags at ambient temperature for 240 days, with three independently stored units per treatment; untreated flour served as the control. Storage was monitored for basic nutritional components, functional components, antioxidant activity, storage-stability indices and microbial counts, and untargeted lipidomics was performed by UPLC-MS/MS to resolve the lipid-level response. All LBP supplementations retarded the loss of nutritional and functional components, with dose-specific optima: 0.2% LBP best preserved protein, total starch, β-glucan and γ-aminobutyric acid, kept DPPH and hydroxyl radical scavenging stable, and most strongly suppressed microbial growth and the rise in peroxide value; 1.0% LBP most effectively limited moisture loss and malondialdehyde accumulation; and 2.0% LBP most strongly suppressed lipase activity, fatty acid value and the decline of polyphenols and flavonoids. Lipidomics identified 819 lipid species. Among the LBP-supplemented groups, the number of differential lipids decreased as the supplementation level increased (255, 216 and 174 for 0.2%, 1.0% and 2.0%, respectively; the control group contained 243), and LBP protected membrane phospholipids (PC, PE), storage lipids (TG) and galactolipids (MGDG) while suppressing the formation of lysophospholipids (LPC, LPE). KEGG enrichment showed that 0.2–1.0% LBP preserved glycerophospholipid and glycerolipid metabolism, whereas 2.0% LBP suppressed even the core lipid metabolic pathways. Considering the overall retention of nutritional and functional components, the stability of antioxidant activity, and the suppression of microbial growth and lipid oxidation, 0.2% LBP is recommended as the optimal supplementation level, while the lipidomic data reveal a dose-dependent, membrane-protective mechanism that supports the application of LBP as a natural preservative for whole-grain flours.