Solute bioconcentration mechanisms in biological material

Abstract

Bioconcentration is a term used to quantify the concentration of a solute within an organism with respect to the source of exposure. Recently, bioconcentration has been a major field of study for analytical and environmental chemists since the rise of synthetic chemicals appearing within the environment. The work described here uses fluorescence spectroscopy, light scattering, and thermoanalytical techniques to describe the impact of bioconcentration mechanisms on the structure and function of biological material, including model biological membranes and transport proteins. The studies performed in this body of work investigate solute-membrane and solute-protein interactions by analyzing the behavior of both the solute, and the biological material of interest in order to uncover the wholistic effect of the solute on a biological system. Each body of work either altered the solute studied for bioconcentration or the biological material itself, to get a deeper understanding of bioconcentration mechanisms. The first body of work describes a study looking into the partitioning behavior of the amino acid L- Phenylalanine into model biological membranes. Experiments showed that L-Phenylalanine integrates into the membrane and experiences a conformationally restricted environment. The second body of work inspects an environmental contaminant known as Perfluorooctanoic acid (PFOA), and the effects it has on lipid bilayer vesicles structure, as well as secondary solute partitioning behavior at concentrations close to the EPA regulatory limits. Experiments revealed that 100 nM PFOA increases membrane fluidity and increases secondary solute partitioning into the acyl chains of the lipid bilayer. The third body of work explores Perfluorooctanoic acid's effects on the protein Human Hemoglobin, and discovered that PFOA induces a change in the fluorescence mechanism of the native Tryptophan residues, and binds at concentrations as low as 10 nM.