Inhibition of amyloid fibril formation of hen egg white lysozyme by trimethylamine N-oxide at low pH.

In vitro inhibition of the formation of fibrous aggregates of proteins (amyloids) has gained increasing attention due to the number of diseases associated with protein misfolding and fibrillation. An interesting group of compounds for which pronounced activity against this phenomenon can be expected consists of low molecular weight substances (osmolytes) which have the ability to change protein stability. Here we investigate the influence of trimethylamine N-oxide (TMAO) in acidic solution (pH=2) on the fibrillation of hen egg white lysozyme (HEWL). The process was monitored by five techniques: circular dichroism in the UV region, atomic force microscopy, dynamic light scattering, densimetry and gel electrophoresis. The obtained results show that protonated TMAO in a concentration of 400 mM inhibits amyloidogenesis. In the conditions of the experiment the HEWL molecules form clusters about 30 nm in diameter containing a relatively high fraction of covalent-bonded dimers.

Influence of microbial adaption and supplementation of nutrients on the biodegradation of ionic liquids in sewage sludge treatment processes.

As ionic liquids are winning more attention from industry as a replacement of more hazardous chemicals, some of their structures have the potential to become persistent pollutants due to high stability towards abiotic and biotic degradation processes. Therefore it is important to determine the hazard associated with the presence of ILs in the environment, for example biodegradation under real conditions. Standard biodegradation testing procedures generally permit pre-conditioning of inoculum but do not allow for pre-exposition to the test substance. These are usually conducted in a mineral medium which does not provide additional organic nutrients. Though very valuable, as a point of reference, these tests do not fully represent real conditions. In in situ conditions, for example in wastewater treatment plants or natural soils and water bodies, the presence of readily available sources of energy and nutrients as well as the process of adaptation may often alter the fate and metabolic pathways of xenobiotics. Our results have shown that these are the opposing processes influencing the biodegradation rate of ILs in sewage sludge. The results have significant practical implications with respect to the assessment of biodegradability and environmental fate of ILs and other xenobiotics in environmental conditions and their potential remediation options.