muramidase and indoleacetic-acid

Amyloid aggregation of polypeptides is related to a growing number of pathologic states known as amyloid disorders. There is a great deal of interest in developing small molecule inhibitors of the amyloidogenic processes. In the present article, the inhibitory effects of some indole derivatives on amyloid fibrillation of hen egg white lysozyme (HEWL) are reported. Acidic pH and high temperatures were used to drive HEWL towards amyloid formation. A variety of techniques, ranging from thioflavin T fluorescence and Congo red absorbance assays to far-UV CD and transmission electron microscopy, were employed to characterize the HEWL fibrillation process. Among the indole derivatives tested, indole 3-acetic acid, indole 3-carbinol and tryptophol had the most inhibitory effects on amyloid formation, indole and indole 3-propionic acid gave some inhibition, and indole aldehyde and tryptophan showed no significant inhibition. Although indoles did not protect the HEWL native state from conformational changes, they were effective in diminishing HEWL amyloid fibril formation, delaying both the nucleation and elongation phases. Disaggregation of previously formed HEWL amyloid fibrils was also enhanced by indole 3-acetic acid. Various medium conditions, such as the presence of different anions and alcoholic cosolvents, were explored to gain an insight into possible mechanisms. These observations, taken together, suggest that the indole ring is likely to play the main role in inhibition and that the side chain hydroxyl group may contribute positively, in contrast to the side chain carbonyl and intervening methylene groups.

Topics: Amyloid; Animals; Binding Sites; Chickens; Circular Dichroism; Hydrogen-Ion Concentration; Indoleacetic Acids; Indoles; Kinetics; Microscopy, Electron, Transmission; Models, Molecular; Molecular Structure; Muramidase; Protein Binding; Protein Conformation; Temperature

Rhizobacteria obtained during a risk assessment study from parental and transgenic T4 lysozyme-expressing potato plants were investigated to determine whether or not the strains could be grouped based on the source of isolation, transgenic or non-transgenic plants, respectively. A total of 68 representative bacterial strains of the group of enterics and pseudomonads were investigated by phenotypic profiling (the antagonistic activity towards bacterial and fungal plant pathogens, the production of the plant growth hormone indole-3-acetic acid [auxin], and the sensitivity to T4 lysozyme in vitro) and genotypic profiling by PCR fingerprints using BOX primers. All isolates were identified by fatty acid methyl ester (FAME) analysis. Computer-based analysis of the phenotypic characteristics showed that both, enterics and Pseudomonas strains clustered into six to seven groups at an Euclidian distance of 10. According to their BOX-PCR-generated fingerprints the Pseudomonas strains clustered into seven groups and the enterobacteria into two groups at the same genetic distance level of 10. The majority of groups were heterogeneous and contained isolates from all plant lines. In conclusion, cluster analysis of the phenotypic and genotypic features did not reveal correlations between bacterial isolates and transgenic character of plants.

Topics: Cluster Analysis; DNA Fingerprinting; DNA, Bacterial; Enterobacteriaceae; Fatty Acids; Indoleacetic Acids; Muramidase; Pectobacterium carotovorum; Plant Roots; Plants, Genetically Modified; Polymerase Chain Reaction; Pseudomonas; Solanum tuberosum; Verticillium