Silver and Gold Nanoparticles Alter Cathepsin Activity In vitro

Nanomaterials are being incorporated into many biological applications for use as therapeutics, sensors, or labels. Silver nanomaterials are being utilized for biological implants and wound dressings as an antiviral material, whereas gold nanomaterials are being used as biological labels or sensors due to their surface properties and biocompatibility. Cytotoxicity data of these materials are becoming more prevalent; however, little research has been performed to understand how the introduction of these materials into cells affects cellular processes. Here, we demonstrate the impact that silver and gold nanoparticles have on cathepsin activity in vitro. Cathepsins are important cellular proteases that are imperative for proper immune system function. We have selected to examine gold and silver nanoparticles due to the increased use of these materials in biological applications. This manuscript depicts how both of these types of nanomaterials affect cathepsin activity, which could impact the host's immune system and its ability to respond to pathogens. Cathepsin B activity decreases in a dose-dependent manner with all nanoparticles tested. Alternatively, the impact of nanoparticles on cathepsin L activity depends greatly on the type and size of the material

CW microwave generation by optical downconversion in a nonlinear AlxGa1-xAs waveguide

Techniques for optical generation of microwave signals have recently received much attention [1]. The generation of narrowband microwave signals from the mixing of two optical sources has been demonstrated using fast photodetectors [2]. This paper describes the first generation of a tuneable, CW, narrowband microwave radiation by mixing two optical sources in a GaAs/AlxGa1-xAs waveguide, utilizing the inherent non-linear properties of the material

Identification of novel inhibitors of the ABC transporter BmrA

The resistance of microbes to commonly used antibiotics has become a worldwide health problem. A major underlying mechanism of microbial antibiotic resistance is the export of drugs from bacterial cells. Drug efflux is mediated through the action of multidrug resistance efflux pumps located in the bacterial cell membranes. The critical role of bacterial efflux pumps in antibiotic resistance has directed research efforts to the identification of novel efflux pump inhibitors that can be used alongside antibiotics in clinical settings. Here, we aimed to find potential inhibitors of the archetypical ATP-binding cassette (ABC) efflux pump BmrA of Bacillus subtilis via virtual screening of the Mu.Ta.Lig. Chemotheca small molecule library. Molecular docking calculations targeting the nucleotide-binding domain of BmrA were performed using AutoDock Vina. Following a further drug-likeness filtering step based on Lipinski's Rule of Five, top 25 scorers were identified. These ligands were then clustered into separate groups based on their contact patterns with the BmrA nucleotide-binding domain. Six ligands with distinct contact patterns were used for further in vitro inhibition assays based on intracellular ethidium bromide accumulation. Using this methodology, we identified two novel inhibitors of BmrA from the Chemotheca small molecule library. © 2020 Elsevier Inc.Marmara Üniversitesi: FEN-B-120917-0534 Agence Nationale de la Recherche: ANR-19-CE11-0023-01 Javna Agencija za Raziskovalno Dejavnost RS: P1-0208 European Cooperation in Science and Technology: CA15135The authors acknowledge Marmara University Scientific Research Projects Committee grant FEN-B-120917-0534 (BSA), COST for Mu.Ta.Lig COST Action CA15135 (TT), Slovenian Research Agency grant P1-0208 (TT, RF), and Agence Nationale de la Recherche (ANR) grant ANR-19-CE11-0023-01 (CO) for support

High-resolution surface-emitting spectrometer and deformation sensors with nonlinear waveguides

We investigate the limits of frequency resolution attainable in a nonlinear waveguide optical spectrometer, including the effects that are due to surface distortions and waveguide inhomogeneities, and demonstrate that the frequency-resolving capability is directly scalable with the radiating aperture length. The resolution of the waveguide is diffraction limited, and therefore the far-field radiation pattern can be used to characterize the phase variations along the waveguide that are due to surface distortions. The use of this device as a highly sensitive deformation sensor is demonstrated by application of a distortion to the waveguide and confirmation of the far-field diffraction pattern generated