The development of therapeutic proteins and peptides is an expensive and time-intensive process. Biologics, which have become a multi-billion dollar industry, are chemically complex products that require constant observation during each stage of development and production. Post-translational modifications along with chemical and physical degradation from oxidation, deamidation, and aggregation, lead to high levels of heterogeneity that affect drug quality and efficacy. The various separation modes of capillary electrophoresis (CE) are commonly utilized to perform quality control and assess protein heterogeneity. This review attempts to highlight the most recent developments and applications of CE separation techniques for the characterization of protein and peptide therapeutics by focusing on papers accepted for publication in the in the two-year period between January 2012 and December 2013. The separation principles and technological advances of CE, capillary gel electrophoresis, capillary isoelectric focusing, capillary electrochromatography and CE-mass spectrometry are discussed, along with exciting new applications of these techniques to relevant pharmaceutical issues. Also included is a small selection of papers on microchip electrophoresis to show the direction this field is moving with regards to the development of inexpensive and portable analysis systems for on-site, high-throughput analysis.

Mimulus guttatus DC. (yellow monkey-flower; Phrymaceae) is an important model species for ecological and evolutionary studies, being locally adapted to a wide range of elevation, moisture and temperature gradients, soil types, and pollinator availabilities. In order to advance this species as a model for evolutionary genetic studies, we have developed virus-induced gene silencing (VIGS) using the tobacco rattle virus (TRV) to assay gene function. We demonstrate the effectiveness of Agrobacterium-mediated VIGS in two divergent populations of M. guttatus, Iron Mountain 767 (IM767) and Point Reyes (PR). Plants infected with a fragment of the carotenoid biosynthesis pathway gene PHYTOENE DESATURASE (PDS) cloned into the TRV2 vector exhibited endogenous PDS silencing and photobleached phenotypes. We further assayed for VIGS-induced floral phenotypes by silencing paralogous genes putatively affecting floral symmetry, CYCLOIDEA1 (CYC1) and CYCLOIDEA2 (CYC2). Simultaneous silencing of CYC1 and CYC2 resulted in organ number defects in the petal and stamen whorls; silencing of CYC1 affected petal margin growth; and silencing of CYC2 had no effect on flower development. Infection with TRV2 and TRV1 is significantly higher and more pervasive in the IM767 versus the PR population and is more efficient after vacuum infiltration. These results demonstrate the efficacy of VIGS for determining the function of developmental genes, including those involved in ecologically important reproductive traits.

A portable fluorescence detection system for use with microchip electrophoresis was developed and compared to a benchtop system. Using this system, six neuroactive amines commonly found in brain dialysate—arginine, citrulline, taurine, histamine, glutamate, and aspartate—were derivatized offline with naphthalene-2,3-dicarboxaldehyde/cyanide, separated electrophoretically, and detected by fluorescence. Limits of detection for the analytes of interest were 50nM – 250nM for the benchtop system and 250 nM – 1.3 μM for the portable system, both of which were adequate for analyte determination in brain microdialysis samples. The portable system was then demonstrated for the detection of the same six amines in a rat brain microdialysis sample.

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