Publications

The outbreak of coronavirus disease (COVID-19) caused by a novel RNA virus emerged at the end of 2019. Most of the patient's symptoms are mild to moderate, and influenza, acute respiratory distress syndrome (ARDS) and multi-organ failure are common. The disease is mild to moderate in most patients and is reported in many cases such as pneumonia, ARDS and multi-organ dysfunction. This study's objective is to evaluate 25 natural compounds from Citrus limon (CL) used by comprehensive molecular docking, density functional theory (DFT) and molecular dynamics analysis against SARS-CoV-2 main protease (M^pro). Among all the experimental compounds, diosmetin has shown the best docking values against the M^pro of SARS-CoV-2 compared to the standard antiviral drug. In DFT calculations, the order associated with biochemical reactivity is as follows: eriodictoyl > quercetin > spinacetin > diosmetin > luteolin > apigenin, whereas the regions of oxygen and hydrogen atoms from the selected isolated compounds are appropriate for electrophilic and nucleophilic attacks, respectively. Also, HOMO-LUMO and global descriptors values indicated a promising result of these compounds. Moreover, a molecular dynamics simulation study revealed the stable conformation and binding pattern in a stimulating environment of natural compounds CL. Considering molecular docking, simulation, and DFT analysis of the selected compounds, notably eriodictoyl, quercetin, and diosmetin showed good potential against SARS-CoV-2 M^pro. Our in silico study revealed promising antiviral activity, which may be considered a potential key factor or a therapeutic target for COVID-19.Communicated by Ramaswamy H. Sarma.

El aceite esencial de la milenrama (Achillea millefolium L. s. l.) presenta un amplio espectro de actividades farmacológicas. Sin embargo, los componentes químicos activos del aceite son sensibles a factores ambientales tales como, luz, oxígeno y temperatura. La encapsulación del aceite esencial ofrece soluciones para esta limitación. El aceite se encapsuló en hidroxipropil-β-ciclodextrina (HPβCD) mediante la técnica de liofilización con un rendimiento del 45%. La formación del complejo de inclusión se analizó mediante técnicas de SEM, FT-IR y UV-vis y se realizó un estudio de solubilidad. El aceite presentó una fuerte actividad antioxidante de 72% de DPPH. HPβCD protege los compuestos activos de aceite esencial y retoene la actividad antioxidante después de la exposición a luz solar. El aceite también exhibió actividad antibacteriana contra Staphylococcus aureus y Escherichia coli con valores mínimos de concentración inhibitoria (MIC) de 250 μg/mL y 500 μg/mL, respectivamente. La eficacia antibacteriana mejoró mucho después de la encapsulación contra S. aureus y E. coli con un valor de CIM de 62,5 μg /ml.

Vibrio vulnificus is the causative agent of primary septicemia, wound infection and gastroenteritis in immunocompromised people. In this study, signature-tagged mutagenesis (STM) was applied to identify the virulence genes of V. vulnificus. Using STM, 6,480 mutants in total were constructed and divided into 81 sets (INPUT pools); each mutant in a set was assigned a different tag. Each INPUT pool was intraperitoneally injected into iron-overloaded mice, and in vivo surviving mutants were collected from blood samples from the heart (OUTPUT pools). From the genomic DNA of mixed INPUT or OUTPUT pools, digoxigenin-labeled DNA probes against the tagged region were prepared and used for dot hybridization. Thirty tentatively attenuated mutants, which were hybridized clearly with INPUT probes but barely with OUTPUT probes, were negatively selected. Lethal doses of 11 of the 30 mutants were reduced to more than 1/100; of these, the lethal doses of 2 were reduced to as low as 1/100,000. Transposon-inserted genes in the 11 attenuated mutants were those for IMP dehydrogenase, UDP-N-acetylglucosamine-2-epimerase, aspartokinase, phosphoribosylformylglycinamidine cyclo-ligase, malate Na (+) symporter and hypothetical protein. When mice were immunized with an attenuated mutant strain into which IMP dehydrogenase had been inserted with a transposon, they were protected against V. vulnificus infection. In this study, we demonstrated that the STM method can be used to search for the virulence genes of V. vulnificus.

Abstract Plexcitonic nanoparticles exhibit strong light‐matter interactions, mediated by localized surface plasmon resonances, and thereby promise potential applications in fields such as photonics, solar cells, and sensing, among others. Herein, these light‐matter interactions are investigated by UV‐visible and surface‐enhanced Raman scattering (SERS) spectroscopies, supported by finite‐difference time‐domain (FDTD) calculations. Our results reveal the importance of combining plasmonic nanomaterials and J‐aggregates with near‐zero‐refractive index. As plexcitonic nanostructures nanorattles are employed, based on J‐aggregates of the cyanine dye 5,5,6,6‐tetrachloro‐1,1‐diethyl‐3,3‐bis(4‐sulfobutyl)benzimidazolocarbocyanine (TDBC) and plasmonic silver‐coated gold nanorods, confined within mesoporous silica shells, which facilitate the adsorption of the J‐aggregates onto the metallic nanorod surface, while providing high colloidal stability. Electromagnetic simulations show that the electromagnetic field is strongly confined inside the J‐aggregate layer, at wavelengths near the upper plexcitonic mode, but it is damped toward the J‐aggregate/water interface at the lower plexcitonic mode. This behavior is ascribed to the sharp variation of dielectric properties of the J‐aggregate shell close to the plasmon resonance, which leads to a high opposite refractive index contrast between water and the TDBC shell, at the upper and the lower plexcitonic modes. This behavior is responsible for the high SERS efficiency of the plexcitonic nanorattles under both 633 nm and 532 nm laser illumination. SERS analysis showed a detection sensitivity down to the single‐nanoparticle level and, therefore, an exceptionally high average SERS intensity per particle. These findings may open new opportunities for ultrasensitive biosensing and bioimaging, as superbright and highly stable optical labels based on the strong coupling effect.