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Abstract

AbstractBioluminescent screeningBacart et al.: Biotechnol. J. 2008, 3, 311–324The bioluminescence resonance energy transfer (BRET) method is based on resonance energy transfer between a light‐emitting enzyme and a fluorescent acceptor. Since its first description in 1999, several versions of BRET have been presented using different substrates and energy donor/acceptor couples. Today, BRET is considered one of the most versatile techniques for studying the dynamics of protein‐protein interactions in living cells. Various studies have applied BRET‐based assays to screen new receptor ligands and inhibitors of disease‐related‐proteases. Inhibitors of proteinprotein interactions are likely to become a new major class of therapeutic drugs, and BRET technology is expected to play an important role in the identification of such compounds. This review describes the original BRET‐based methodology, more recent variants, and potential applications to drug screening.Switchgrass transformationMazarei et al.: Biotechnol. J. 2008, 3, 354–359Transient assay systems using protoplasts have been utilized in several plant species and are a powerful tool for rapid functional gene analysis and biochemical manipulations. A protoplast system has not been used in switchgrass (Panicum virgatum L.), even though it is a bioenergy crop that has received considerable attention. Here researchers from Knoxville (TN, USA) and Palestine report the first protocol to isolate large numbers of viable protoplasts from both leaves and roots of two switchgrass genotypes. They show that protoplast transformation with either a 35S or a ubiquitin promoter resulted in an increase in GUS activity compared to the untransformed controls. Their results indicate an efficient protoplast isolation and a transient assay system that can be used to facilitate gene expression studies in switchgrass.Stem cells on chipsJu et al.: Biotechnol. J. 2008, 3, 383–391Directional induction and differentiation of mesenchymal stem cells (MSCs) is very important to clinical therapy, but the mechanisms that govern differentiation are not well understood. Traditional plate culture cannot precisely control cellular behavior because cells take up substances while secreting cytokines and wastes. Here, Chinese researchers used a microfluidic device to culture MSCs inside a microchamber. Hepatic differentiation medium was perfused to evaluate the ability of MSCs to differentiate toward hepatic cells on the chip. Parallel differentiation on 96‐well plates was used to provide a detailed comparison of the differences between the two culturing methods. Their results indicate that a microfluidic platform might be a potential tool for cost‐effective and automated cell culture, and has potential applications in reliable cell‐based screens and assays.