Structure-based drug designing and immunoinformatics approach for SARS-CoV-2.

The prevalence of respiratory illness caused by the novel SARS-CoV-2 virus associated with multiple organ failures is spreading rapidly because of its contagious human-to-human transmission and inadequate globalhealth care systems. Pharmaceutical repurposing, an effective drug development technique using existing drugs, could shorten development time and reduce costs compared to those of de novo drug discovery. We carried out virtual screening of antiviral compounds targeting the spike glycoprotein (S), main protease (Mpro), and the SARS-CoV-2 receptor binding domain (RBD)-angiotensin-converting enzyme 2 (ACE2) complex of SARS-CoV-2. PC786, an antiviral polymerase inhibitor, showed enhanced binding affinity to all the targets. Furthermore, the postfusion conformation of the trimeric S protein RBD with ACE2 revealed conformational changes associated with PC786 drug binding. Exploiting immunoinformatics to identify T cell and B cell epitopes could guide future experimental studies with a higher probability of discovering appropriate vaccine candidates with fewer experiments and higher reliability.

Selective in vivo molecular and cellular biocompatibility of black peppercorns by piperine-protein intrinsic atomic interaction with elicited oxidative stress and apoptosis in zebrafish eleuthero embryos.

Day to day consumption of black pepper raise concern about the detailed information about their medicinal, pharmaceutical values and knowledge about the biocompatibility with respect to ecosystem. This study investigates the in vivo selective molecular biocompatibility of its seed cover (SC) and seed core (SP) powder extract using embryonic zebrafish model. Gas chromatography mass spectrometry (GCMS) analysis of the extract prepared by grinding showed presence of different components with "piperine" as principle component. Biocompatibility analysis showed dose and time dependent selective effect of SC and SP with LC50 of 30.4 µg/ml and 35.6 µg/ml, respectively on survivability, hatching and heartbeat rate in embryonic zebrafish. Mechanistic investigation elucidated it as effect of accumulation and internalization of black pepper leading to their influence on structure and function of cellular proteins hatching enzyme (he1a), superoxide dismutase (sod1) and tumor protein (tp53) responsible for delayed hatching, oxidative stress induction and apoptosis. The study provided insight to selective biocompatibility of black pepper expedient to produce higher quality spices with respect to pharmaceutical, clinical and environmental aspects.

Biogenic Au@ZnO core-shell nanocomposites kill Staphylococcus aureus without provoking nuclear damage and cytotoxicity in mouse fibroblasts cells under hyperglycemic condition with enhanced wound healing proficiency.

The aim of the present study is focused on the synthesis of Au@ZnO core-shell nanocomposites, where zinc oxide is overlaid on biogenic gold nanoparticles obtained from Hibiscus Sabdariffa plant extract. Optical property of nanocomposites is investigated using UV-visible spectroscopy and crystal structure has been determined using X-ray crystallography (XRD) technique. The presence of functional groups on the surface of Au@ZnO core-shell nanocomposites has been observed by Fourier transforms infrared (FTIR) spectroscopy. Electron microscopy studies revealed the morphology of the above core-shell nanocomposites. The synthesized nanocomposite material has shown antimicrobial and anti-biofilm activity against Staphylococcus aureus and Methicillin Resistant Staphylococcus haemolyticus (MRSH). The microbes are notorious cross contaminant and are known to cause infection in open wounds. The possible antimicrobial mechanism of as synthesized nanomaterials has been investigated against Staphylococcus aureus and obtained data suggests that the antimicrobial activity could be due to release of reactive oxygen species (ROS). Present study has revealed that surface varnishing of biosynthesized gold nanoparticles through zinc oxide has improved its antibacterial proficiency against Staphylococcus aureus, whereas reducing its toxic effect towards mouse fibroblast cells under normal and hyperglycaemic condition. Further studies have been performed in mice model to understand the wound healing efficiency of Au@ZnO nanocomposites. The results obtained suggest the possible and effective use of as synthesized core shell nanocomposites in wound healing.

Doped ZnO nanoparticles impregnated on Kaolinite (Clay): A reusable nanocomposite for photocatalytic disinfection of multidrug resistant Enterobacter sp. under visible light.

Water contamination by multidrug resistant (MDR) enteric bacteria can be considered as the foremost cause of gastrointestinal infections and poses a threat to global public health. Therefore, there is an urgent need to pursue unorthodox techniques with potential of community scale applications for purging of water borne pathogenic bacteria. We communicate visible-light assisted photocatalytic disinfection (PCD) of an enteric MDR bacterium; Enterobacter sp. using Fe-doped ZnO nanoparticles impregnated on Kaolinite (Clay) (ZnO/K). ZnO/K was synthesized by co-precipitation technique and was found to be more effective than Fe-doped ZnO (ZnO) and Kaolinite for PCD process. Analysis from fluorescence microscopy and electron microscopy (FESEM) proposed complete bacterial cell death via PCD due to damage of bacterial cell membrane. Experimental evidences indicated that O2- could be acting as the most significant component in disinfection of MDR Enterobacter sp. in visible-light assisted PCD process in presence of ZnO/K. Considering the experimental data of Resazurin assay, it is proposed that reactive oxygen species (ROS) generated during PCD might have impeded the oxido-reductase enzyme system of the bacteria and hence trammeling its metabolic activity. Crystal structure and particle size of ZnO/K was found to be unaltered during the photocatalytic process indicating its potential for reusability. When ZnO/K was exposed to HCT-116 Human Colorectal Carcinoma cell lines, about 79% cell survivability was noticed. The synthesized material was successful in completely disinfecting the target microorganism in Zebra Fish model, without producing any adverse effects on the Fish itself, further reinforcing its biocompatibility factor. High effectiveness of PCD process using ZnO/K under visible light in disinfecting enteric MDR bacteria, might have promising outcome as an alternative water disinfection technology to prevent the spread of infectious and resistant bacteria without producing any adverse effect on non-specific flora and fauna.

Photo-bioreduction of Ag+ ions towards the generation of multifunctional silver nanoparticles: Mechanistic perspective and therapeutic potential.

In this article, light induced plant extract mediated one pot synthesis of silver nanoparticles (AgNPs) has been demonstrated and potential mechanistic insight in the synthesis has been investigated. Bioactive molecules containing medicinal plant Cassytha filiformis has been explored for the synthesis of silver nanoparticles. The as-synthesized silver nanoparticles were characterized by various analytical techniques including Ultraviolet-visible spectroscopy (UV-Vis), High Resolution Transmission Electron Microscopy (HR-TEM), Dynamic Light Scattering (DLS) and Fourier Transform Infrared Spectroscopy (FT-IR). Among different light sources (sunlight, room light, UV) applied the sunlight was found to be efficient external stimuli to induce rapid synthesis of AgNPs at room temperature. Modified DPPH assay indicated that polyphenolic compounds were most likely involved in the synthesis of AgNPs. Possible molecule responsible for the synthesis of AgNPs was identified, purified and characterized. Potential biomedical applications such as antibacterial, antifungal and anticancer activities of AgNPs have been evaluated. Irrespective of nature of pathogenic strains nanoparticles exhibited significant antibacterial activities against Gram positive (Streptococcus aureus) and Gram negative (Escherichia coli) bacterial pathogens. It showed higher activity on E. coli than on S. aureus. Distinct antifungal activity (MIC=5.244µg/ml) and remarkable anticancer activity (IC50=10µg/ml) was found against Candida albicans and HCT116 (colorectal carcinoma) cells, respectively. Taken together, these findings suggested that light induced plant generated silver nanoparticles could be used for various biomedical purposes.

Enhanced biodegradation of hexachlorocyclohexane (HCH) in contaminated soils via inoculation with Sphingobium indicum B90A.

Soil pollution with hexachlorocyclohexane (HCH) has caused serious environmental problems. Here we describe the targeted degradation of all HCH isomers by applying the aerobic bacterium Sphingobium indicum B90A. In particular, we examined possibilities for large-scale cultivation of strain B90A, tested immobilization, storage and inoculation procedures, and determined the survival and HCH-degradation activity of inoculated cells in soil. Optimal growth of strain B90A was achieved in glucose-containing mineral medium and up to 65% culturability could be maintained after 60 days storage at 30 degrees C by mixing cells with sterile dry corncob powder. B90A biomass produced in water supplemented with sugarcane molasses and immobilized on corncob powder retained 15-20% culturability after 30 days storage at 30 degrees C, whereas full culturability was maintained when cells were stored frozen at -20 degrees C. On the contrary, cells stored on corncob degraded gamma-HCH faster than those that had been stored frozen, with between 15 and 85% of gamma-HCH disappearance in microcosms within 20 h at 30 degrees C. Soil microcosm tests at 25 degrees C confirmed complete mineralization of [(14)C]-gamma-HCH by corncob-immobilized strain B90A. Experiments conducted in small pits and at an HCH-contaminated agricultural site resulted in between 85 and 95% HCH degradation by strain B90A applied via corncob, depending on the type of HCH isomer and even at residual HCH concentrations. Up to 20% of the inoculated B90A cells survived under field conditions after 8 days and could be traced among other soil microorganisms by a combination of natural antibiotic resistance properties, unique pigmentation and PCR amplification of the linA genes. Neither the addition of corncob nor of corncob immobilized B90A did measurably change the microbial community structure as determined by T-RFLP analysis. Overall, these results indicate that on-site aerobic bioremediation of HCH exploiting the biodegradation activity of S. indicum B90A cells stored on corncob powder is a promising technology.