Systematic Assessment of Seven Solvent and Solid-Phase Extraction Methods for Metabolomics Analysis of Human Plasma by LC-MS.

The comparison of extraction methods for global metabolomics is usually executed in biofluids only and focuses on metabolite coverage and method repeatability. This limits our detailed understanding of extraction parameters such as recovery and matrix effects and prevents side-by-side comparison of different sample preparation strategies. To address this gap in knowledge, seven solvent-based and solid-phase extraction methods were systematically evaluated using standard analytes spiked into both buffer and human plasma.

Intracellular adaptation of Brucella abortus.

Macrophages were infected with virulent Brucella abortus strain 2308 or attenuated strain 19. Intracellular bacteria were recovered at different times after infection and their proteomes compared. The virulent strain initially reduced most biosynthesis and altered its respiration; adaptations reversed later in infection.

Peptide Shifter: enhancing separation reproducibility using correlated expression profiles.

Chromatographic protein and peptide separation technologies enable comprehensive proteomic analysis of plasma and other complex biological samples by mass spectrometry. However, as the number of separations and/or fractions increases, so does the number of peptides split across fraction boundaries. Irreproducibility of peptide chromatographic separation results in peptides on or near the boundary moving partially or entirely into adjacent fractions.

Protein depletion from blood plasma using a volatile buffer.

Removal of high abundance proteins is widely used in sample processing for proteomics studies of blood plasma. Immunoaffinity (IA) depletion is currently the most specific method for performing this step. Historically, IA depletion matrices have been designed to be used with inorganic buffers.