Polarization optical-histochemical characterization and supramolecular structure of carbohydrate fibrils.

Topo-optical staining reactions were used to investigate the structures of bacterial cellulose, insect chitosan and alginic acid from brown algae. Polysaccharide complexes, glycosaminoglycans and sulfate groups were presented and demonstrated selectively. Chitosan and alginic acid are structurally similar to glycosaminoglycans (GAGs), which are constituents of human amyloid fibrils.

Paired helical filaments contain small amounts of cholesterol, phosphatidylcholine and sphingolipids.

By using qualitative and quantitative high-performance thin layer chromatography (hpTLC) we found lipids associated with purified Alzheimer's (AD) paired helical filaments (PHF) in an amount of 1.4+/-0.2% of the total anhydrous mass.

Topooptical investigations and enzymatic digestions on tissue-isolated amyloid fibrils.

Chemical and biochemical analysis of isolated amyloid fibrils reveals the presence of different classes of proteins which are often related to distinct clinical forms of amyloidosis and are useful to classify the amyloid deposits. In this study, enzymatic digestions using hyaluronidase, chondroitinase AC and B, neuraminidase, and chemical extractions using mild acid hydrolysis with hydrochloric and sulfuric acid, were used to control the specificity of various topooptical reactions. The disappearance of intense staining after these extraction methods indicates that tissue-isolated amyloid fibrils contain sialic acids and glycosaminoglycans (GAGs).

The TatAd component of the Bacillus subtilis twin-arginine protein transport system forms homo-multimeric complexes in its cytosolic and membrane embedded localisation.

The twin arginine translocation (Tat) system has the capacity to transfer completely folded proteins across the bacterial cytoplasmic membrane and the thylakoid membrane of plant chloroplasts. The most abundant TatA protein of this system has been suggested to form the protein conducting channel. Here, the molecular organisation of soluble and membrane embedded Bacillus subtilis TatAd was analysed using negative contrast and freeze-fractured electron microscopy.

Acid inactivation of prions: efficient at elevated temperature or high acid concentration.

Scrapie prion rods isolated from hamster and non-infectious aggregates of the corresponding recombinant protein rPrP(90-231) were incubated with hydrochloric acid. The amount of PrP and of infectivity that survived incubation in HCl at varying times, acid concentrations and temperatures was quantified by Western blot densitometry and bioassays, respectively. Prion rods and rPrP aggregates showed similar HCl hydrolysis kinetics of PrP, indicating structural homology.

Histochemical and topo-optical investigations on tissue-isolated and in vitro amyloid fibrils.

An improved microscopic slide preparation for staining of tissue-isolated and in vitro amyloid fibrils is described in detail. Specimens were prepared by slow drying of an amyloid fibril suspension on aminoalkyl-silanised glass slides underneath a coverglass. The purpose of this method is to obtain microscopically visible fibers.

Raft lipids as common components of human extracellular amyloid fibrils.

Amyloid fibrils are fibrillar polypeptide aggregates from several degenerative human conditions, including Alzheimer's and Creutzfeldt-Jakob diseases. Analysis of amyloid fibrils derived from various human diseases (AA, ATTR, Abeta2M, ALlambda, and ALkappa amyloidosis) shows that these are associated with a common lipid component that has a conserved chemical composition and that is specifically rich in cholesterol and sphingolipids, the major components of cellular lipid rafts. This pattern is not notably affected by the purification procedure, and no tight lipid interactions can be detected when preformed fibrils are mixed with lipids.

Heat stability of prion rods and recombinant prion protein in water, lipid and lipid-water mixtures.

Prion rods, i.e. insoluble infectious aggregates of the N-terminally truncated form of the prion protein, PrP 27-30, and the corresponding recombinant protein, rPrP(90-231), were autoclaved in water, bovine lipid or lipid-water mixtures for 20 min at temperatures from 100 to 170 degrees C.