Search results for " oligomer"

In vitro 30 nm silver nanoparticles promote chondrogenesis of human mesenchymal stem cells

2015

Silver nanoparticles (Ag NPs) are one of the most widely used products in nano-medicine due to their broad-spectrum antimicrobial activity. In tissue engineering, Ag NPs are often incorporated as antibacterial agents in scaffolds, which are subsequently loaded with human bone marrow-derived mesenchymal stem cells (hMSCs). In this study, we investigated the effect of Ag NPs on chondrogenesis of hMSCs. The synthesized Ag NPs were spherical in shape, with a mean diameter of ∼30 nm. After 24 h exposure, Ag NPs were taken up into hMSCs and mainly distributed in the cytoplasm, the nucleus and different sized vesicles. We examined the chondrogenesis through several methods, including glycosaminogl…

Regulation of the inflammatory response by tin protoporphyrin IX in the rat anterior cruciate ligament transection model of osteoarthritis

2010

The purpose of this study was to investigate several inflammatory mediators and cartilage degradation molecules as possible biomarkers of joint lesion in the anterior cruciate ligament transection (ACLT) model of osteoarthritis in rats. We also assessed whether the treatment with the anti-inflammatory agent tin protoporphyrin IX (SnPP) reduces the progression of disease. Our results indicate that serum levels of interleukin (IL)-6 and PGE2 are significantly increased in ACLT rats 10 weeks after surgery, whereas the increases in IL-1β and tumor necrosis-α were not significant. In addition, our data suggest that IL-17 is the main pro-inflammatory cytokine in the ACLT joint. We have shown that…

Streptolysin O: the C-terminal, tryptophan-rich domain carries functional sites for both membrane binding and self-interaction but not for stable oli…

2001

AbstractStreptolysin O belongs to the class of thiol-activated toxins, which are single chain, four-domain proteins that bind to membranes containing cholesterol and then assemble to form large oligomeric pores. Membrane binding involves a conserved tryptophan-rich sequence motif located within the C-terminally located domain 4. In contrast, sites involved in oligomerization and pore formation have been assigned to domains 1 and 3, respectively. We here examined the functional properties of domain 4, which was recombinantly expressed with an N-terminal histidine tag for purification and an additional cysteine residue for covalent labeling. The fluorescently labeled fragment readily bound to…

Assembly mechanism of the oligomeric streptolysin O pore: the early membrane lesion is lined by a free edge of the lipid membrane and is extended gra…

1998

Streptolysin O (SLO) is a bacterial exotoxin that binds to cell membranes containing cholesterol and then oligomerizes to form large pores. Along with rings, arc-shaped oligomers form on membranes. It has been suggested that each arc represents an incompletely assembled oligomer and constitutes a functional pore, faced on the opposite side by a free edge of the lipid membrane. We sought functional evidence in support of this idea by using an oligomerization-deficient, non-lytic mutant of SLO. This protein, which was created by chemical modification of a single mutant cysteine (T250C) with N-(iodoacetaminoethyl)-1-naphthylamine-5-sulfonic acid, formed hybrid oligomers with active SLO on memb…

Introduction and Technical Survey: Protein Aggregation and Fibrillogenesis

2012

In this chapter we provided the overall background to the subject of protein aggregation and fibrillogenesis in amyloidogenesis, with introduction and brief discussion of the various topics that are included with the coming chapters. The division of the book into basic science and clinical science sections enables correlation of the topics to be made. The many proteins and peptides that have currently been found to undergo fibrillogenesis are tabulated. A broad technical survey is made, to indicate the vast array of techniques currently available to study aspects of protein oligomerization, aggregation and fibrillogenesis. These are split into three groups and tabulated, as the microscopica…

Novel Imidazolium Based Catalyst for the Chemical Fixation of Carbon Dioxide

2015

FERULIC ACID INHIBITS OXIDATE STRESS AND CELL DEATH INDUCED BY Ab OLIGOMERS: IMPROVED DELIVERY BY SOLID LIPID NANOPARTICLES.

2009

Oxidative stress and dysfunctional mitochondria are among the earliest events in AD, triggering neurodegeneration. The use of natural antioxidants could be a neuroprotective strategy for blocking cell death. Here, the antioxidant action of ferulic acid (FA) on different paths leading to degeneration of recombinant beta-amyloid peptide (rAbeta42) treated cells was investigated. Further, to improve its delivery, a novel drug delivery system (DDS) was used. Solid lipid nanoparticles (SLNs), empty or containing ferulic acid (FA-SNL), were developed as DDS. The resulting particles had small colloidal size and highly negative surface charge in water. Using neuroblastoma cells and rAbeta42 oligome…

2,5-Bis[(E)-2-phenylethenyl]-3,6-bis(pyridin-2-yl)pyrazine

2020

The molecule of the title compound, C30H22N4, exhibits inversion symmetry adopting the shape of a St Andrew's Cross. It shows dihedral angles between adjacent aryl units of around 50° whereas torsion angles of ca 10° are found along the arylene vinylene path.

Propyl substituted 4-arylimino-1,2,3-trihydroacridylnickel complexes: Their synthesis, characterization and catalytic behavior toward ethylene

2015

Propyl substituted 4-arylimino-1,2,3-trihydroacridylnickel dihalide complexes were designed and prepared by metal-induced template reaction with NiCl2 center dot 6H(2)O or (DME)NiBr2. They were characterized by infrared spectroscopy and elemental analysis. Single crystal X-ray crystallography of representative complex Ni3 revealed a distorted trigonal bipyramidal geometry around nickel. The catalytic activities of the title nickel complexes were negatively affected by propyl substituent on their backbone when comparing with the results by unsubstituted ones. With the activation of diethylaluminium chloride, all nickel complexes exhibited moderate activity (up to 5.10 x 10(5) g mol(-1)(Ni) h…

Vibrio cholerae cytolysin: assembly and membrane insertion of the oligomeric pore are tightly linked and are not detectably restricted by membrane fl…

2000

AbstractHemolytic strains of Vibrio cholerae secrete a cytolysin that, upon binding as a monomer, forms pentameric pores in animal cell membranes. Pore formation is inhibited at low temperature and in the absence of cholesterol. We here posed the following questions: firstly, can oligomerization be observed in the absence of pore formation? Secondly, is membrane fluidity responsible for the effect of temperature or of cholesterol upon pore formation? The first issue was approached by chemical cross-linking, by electrophoretic heteromer analysis, and by electron microscopy. None of these methods yielded any evidence of a non-lytic pre-pore oligomer. The second question was addressed by the u…