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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.tibs.2009.03.009 Byline: Natalia S. de Groot, Raimon Sabate, Salvador Ventura Abstract: Protein misfolding and aggregation into amyloid structures are associated with dozens of human diseases. Recent studies have provided compelling evidence for the existence of highly ordered, amyloid-like conformations in the insoluble inclusion bodies produced during heterologous protein expression in bacteria. Thus, amyloid aggregation seems to be an omnipresent process in both eukaryotic and prokaryotic organisms. Amyloid formation inside cell factories raises important safety concerns with regard to the toxicity and infectivity of recombinant proteins. Yet such findings also suggest that prokaryotic cells could be useful systems for studying how and why proteins aggregate in vivo, and they could also provide a biologically relevant background for screening therapeutic approaches to pathologic protein deposition. Author Affiliation: Departament de Bioquimica i Biologia Molecular and Institut de Biotecnologia i de Biomedicina, Universitat AutA[sup.2]noma de Barcelona, 08193 Bellaterra, Barcelona, Spain

The existence of micelles in the fibrillogenesis of Abeta is demonstrated. It is suggested that to maintain the universality of the kinetic curves above the critical micellar concentration (CMC), a direct connection between micelles and nuclei must exist.

The interaction of pinacyanol, a cationic cyannie dye (PIN), with Triton X-100, sodium dodecyl sulfate, and alkyltrimethylammonium bromide micelles was studied by visible spectrophotometry. PIN exists as a monomer and in aggregated form (dimers, trimers, and higher aggregates) in aqueous solution, but dimers and higher aggregates were split into monomers in the presence of surfactants (or on addition of organic solvents).

A spectrophotometric experiment has been developed for students of physical chemistry. The influence of the dielectric constant on the spectral behavior of pinacyanol is investigated. The solvent is methanol/water. Several pedagogical goals included introducing students to concepts of bathochromic and hypochromic shift as well to as hyperchromic and hypochromic effects. Students see an example of solvatochromism and are exposed in discussion to ways in which the kind of electronic transition can be found from the influence of polarity on the UV-vis spectrum.