Currently, the detection of pathogens such as Escherichia coli through instrumental alternatives with fast response and excellent sensitivity and selectivity are being studied. Biosensors are systems consisting of nanomaterials and biomolecules that exhibit remarkable properties such as simplicity, portable, affordable, user‑friendly, and deliverable to end‑users. For this, in this work we report for the first time, to our knowledge, the bioinformatic design of a new peptide based on TIR protein, a receptor of Intimin membrane protein which is characteristic of E. coli. This peptide (named PEPTIR‑1.0) was used as recognition element in a biosensor based on AuNPs‑modified screen‑printed electrodes for the detection of E. coli. The morphological and electrochemical characteristics of the biosensor obtained were studied. Results show that the biosensor can detect the bacteria with limits of detection and quantification of 2 and 6 CFU/mL, respectively. Moreover, the selectivity of the system is statistically significant towards the detection of the pathogen in the presence of other microorganisms such as P. aeruginosa and S. aureus. This makes this new PEPTIR‑1.0 based biosensor can be used in the rapid, sensitive, and selective detection of E. coli in aqueous matrices.

Currently, there are no therapies to prevent severe dengue disease. Essential oils (EOs) can serve as primary sources for research and the discovery of phytomedicines for alternative therapy. Fourteen EOs samples were obtained by distillation from six plants used in Colombian folk medicine. GC/MS analysis identified 125 terpenes. Cytopathic effect (CPE) reduction assays revealed differences in antiviral activity. EOs of Lippia alba, citral chemotype and carvone-rich fraction; Lippia origanoides, phellandrene chemotype; and Turnera diffusa, exhibited strong antiviral activity (IC₅₀: 29 to 82 µg/mL; SI: 5.5 to 14.3). EOs of Piper aduncum, Ocimum basilicum, and L. origanoides, carvacrol, and thymol chemotypes, exhibited weak antiviral activity (32 to 53% DENV-CPE reduction at 100 µg/mL; SI > 5.0). Cluster and one-way ANOVA analyses suggest that the strong antiviral activity of EOs could be attributed to increased amounts of non-phenolic oxygenated monoterpenes and sesquiterpene hydrocarbons. Docking analyses (AutoDock Vina) predicted binding affinity between the DENV-2 E protein and terpenes: twenty sesquiterpene hydrocarbons (−8.73 to −6.91 kcal/mol), eight oxygenated monoterpenes (−7.52 to −6.98 kcal/mol), and seven monoterpene hydrocarbons (−7.60 to −6.99 kcal/mol). This study reports for the first time differences in the antiviral activity of EOs against DENV, corresponding to their composition of monoterpenes and sesquiterpenes.

The Ib-M6 peptide has antibacterial activity against non-pathogenic Escherichia coli K-12 strain. The first part of this study determines the antibacterial activity of Ib-M6 against fourteen pathogenic strains of E. coli O157:H7. Susceptibility assay showed that Ib-M6 had values of Minimum Inhibitory Concentration (MIC) lower than streptomycin, used as a reference antibiotic. Moreover, to predict the possible interaction between Ib-M6 and outer membrane components of E. coli, we used molecular docking simulations where FhuA protein and its complex with Lipopolysaccharide (LPS–FhuA) were used as targets of the peptide. FhuA/Ib-M6 complexes had energy values between −39.5 and −40.5 Rosetta Energy Units (REU) and only one hydrogen bond. In contrast, complexes between LPS–FhuA and Ib-M6 displayed energy values between −25.6 and −40.6 REU, and the presence of five possible hydrogen bonds. Hence, the antimicrobial activity of Ib-M6 peptide shown in the experimental assays could be caused by its interaction with the outer membrane of E. coli.