Browsing by Subject "Surface-Active Agents"
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Item Open Access Cationic amphiphilic Zn-porphyrin with high antifungal photodynamic potency.(Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology, 2017-11) Moghnie, Sara; Tovmasyan, Artak; Craik, James; Batinic-Haberle, Ines; Benov, LudmilPhotodynamic therapy (PDT) is a promising alternative approach particularly attractive for treatment of localized fungal infections. It is based on compounds, photosensitizers (PSs), which when excited with visible light, generate reactive species that ultimately cause cell death. Such species have short lifespans; as a consequence, efficiency and selectivity of the PDT treatment depend mainly on the properties of the PSs. This study is the first to explore the effect of cationic porphyrin-based photosensitizers on Saccharomyces cerevisiae, a member of the fungus kingdom. The study investigates which properties of the PS are essential for efficient antifungal PDT. Cationic Zn(ii) meso-tetrakis(N-alkylpyridinium-2-yl)porphyrins (ZnP) with identical tetrapyrrole core and photo-physical properties, but with different substituents at the meso positions of the porphyrin ring were studied. Attaching six-carbon aliphatic chains to the four pyridyl nitrogens at all meso positions to the porphyrin ring produced a highly photo-efficient amphiphilic, water soluble PS, with minimal dark toxicity. It was taken up by the yeast cells and upon illumination suppressed metabolism by inactivating cytoplasmic and mitochondrial enzymes, and compromising plasma membrane barrier function. At low concentrations (up to 5 μM) the tetrahexyl derivative was a much more powerful antifungal agent than the commercially available chlorin e6. The more lipophilic tetraoctyl analog was also highly photo-efficient but displayed strong dark toxicity, presumably due to higher lipophilicity which might affect the lipid bilayer of membranes. Results presented here can assist the design of antifungal agents whose biological action depends on efficient and rapid uptake by the cells.Item Open Access Elucidating the Molecular Composition of Cartilage by Proteomics.(J Proteome Res, 2016-02-05) Hsueh, Ming-Feng; Khabut, Areej; Kjellström, Sven; Önnerfjord, Patrik; Kraus, Virginia ByersArticular cartilage consists of chondrocytes and two major components, a collagen-rich framework and highly abundant proteoglycans. Most prior studies defining the zonal distribution of cartilage have extracted proteins with guanidine-HCl. However, an unextracted collagen-rich residual is left after extraction. In addition, the high abundance of anionic polysaccharide molecules extracted from cartilage adversely affects the chromatographic separation. In this study, we established a method for removing chondrocytes from cartilage sections with minimal extracellular matrix protein loss. The addition of surfactant to guanidine-HCl extraction buffer improved protein solubility. Ultrafiltration removed interference from polysaccharides and salts. Almost four-times more collagen peptides were extracted by the in situ trypsin digestion method. However, as expected, proteoglycans were more abundant within the guanidine-HCl extraction. These different methods were used to extract cartilage sections from different cartilage layers (superficial, intermediate, and deep), joint types (knee and hip), and disease states (healthy and osteoarthritic), and the extractions were evaluated by quantitative and qualitative proteomic analyses. The results of this study led to the identifications of the potential biomarkers of osteoarthritis (OA), OA progression, and the joint specific biomarkers.