Christensensylvest2017

The wide distribution of this abundant riboswitch class, coupled with the striking diversity of other guanidine-sensing RNAs, demonstrates that many bacterial species maintain sophisticated sensory and genetic mechanisms to avoid guanidine toxicity. This finding further highlights the mystery regarding the natural source of this nitrogen-rich chemical moiety.Currently, research on cardiac injury by aconitine focuses on its effect to directly interfere with the function of cardiac ion channels. Further, abnormal lipid metabolism could cause cardiac injury via inflammatory signaling pathway. In our preliminary study, we discovered that aconitine could alter the metabolism processes of various substances, including palmitic acid. Inspired by these studies, we investigated how elevation of palmitic acid by aconitine causes cardiac injury. Aconitine induced cardiac injury in rats (0.32 mg/kg, d = 7), and the cardiac injury was confirmed by electrocardiogram and serum biochemical study. The proteomic and metabolomic results showed that the palmitic acid level increases in heart tissue, and the NOD-like receptor (NLR) signaling pathway showed a strong effect of cardiac injury. The palmitic acid results in cell viability decline and activates NLR signaling in vitro. The shRNA-mediated knockdown of NLRP3 and NOD1/2 attenuates palmitic acid-induced inhibitory effect on cells and inhibited activation of the NLR signaling pathway. Collectively, this study reveals that aconitine provoked palmitic acid elevation could aggravate cardiac injury via the NLR signaling pathway. This study suggests that drug triggered disorder of the metabolism process could evoke cardiac injury and could propose a new strategy to study drug cardiac injury.Chromosomal expression of heterologous genes offers stability and maintenance advantages over episomal expression, yet remains difficult to optimize through site-specific integration. The challenge has in large part been due to the variability of chromosomal gene expression, which has only recently been shown to be affected by multiple factors, including the local genomic context. In this work we utilize Tn5 transposase to randomly integrate a three-gene csc operon encoding nonphosphotransferase sucrose catabolism into the E. coli K-12 chromosome. Isolates from the transposon library yielded a range of growth rates on sucrose as the sole carbon source, including some that were comparable to that of E. coli K-12 on glucose (μmax = 0.70 ± 0.03 h-1). Narrowness of the growth rate distributions and faster growth compared to plasmids indicate that efficient csc expression is attainable. Furthermore, enhanced growth rate upon transduction into strains that underwent adaptive laboratory evolution indicate that sucrose catabolism is not limiting to cellular growth. We also show that transduction of a csc fast-growth locus into an isobutanol production strain yields high titer (7.56 ± 0.25 g/L) on sucrose as the sole carbon source. Our results demonstrate that random integration is an effective strategy for optimizing heterologous expression within the context of cellular metabolism for both fast growth and biochemical production phenotypes.More than 100 monoclonal antibodies (mAbs) are in industrial and clinical development to treat myriad diseases. Accurate quantification of mAbs in complex media, derived from industrial and patient samples, is vital to determine production efficiency or pharmacokinetic properties. To date, mAb quantification requires time and labor-intensive assays. Herein, we report a novel dual-affinity ratiometric quenching (DARQ) assay, which combines selective biorecognition and quenching of fluorescence signals for rapid and sensitive quantification of therapeutic monoclonal antibodies (mAbs). The reported assay relies on the affinity complexation of the target mAb by the corresponding antigens and Protein L (PrL, which targets the Fab region of the antibody), respectively, labeled with fluorescein and rhodamine. Within the affinity complex, the mAb acts as a scaffold framing the labeled affinity tags (PrL and antigen) in a molecular proximity that results in ratiometric quenching of their fluorescence emission. Notably, the decrease in fluorescence emission intensity is linearly dependent upon mAb concentration in solution. Control experiments conducted with one affinity tag only, two tags labeled with equal fluorophores, or two tags labeled with fluorophores of discrete absorbance and emission bands exhibited significantly reduced effect. Onalespib chemical structure The assay was evaluated in noncompetitive (pure mAb) and competitive conditions (mAb in a Chinese Hamster Ovary (CHO) cell culture harvest). The "DARQ" assay is highly reproducible (coefficient of variation ∼0.8-0.7%) and rapid (5 min), and its sensitivity (∼0.2-0.5 ng·mL-1), limit of detection (75-119 ng·mL-1), and dynamic range (300-1600 ng·mL-1) are independent of the presence of CHO host cell proteins.Recent interest in potassium-doped p-terphenyl has been fueled by reports of superconductivity at Tc values surprisingly high for organic compounds. Despite these interesting properties, studies of the structure-function relationships within these materials have been scarce. Here, we isolate a phase-pure crystal of potassium-doped p-terphenyl [K(222)]2[p-terphenyl3]. Emerging antiferromagnetism in the anisotropic structure is studied in depth by magnetometry and electron spin resonance. Combining these experimental results with density functional theory calculations, we describe the antiferromagnetic coupling in this system that occurs in all 3 crystallographic directions. The strongest coupling was found along the ends of the terphenyls, where the additional electron on neighboring p-terphenyls antiferromagnetically couple. This delocalized bonding interaction is reminiscent of the doubly degenerate resonance structure depiction of polyacetylene. These findings hint toward magnetic fluctuation-induced superconductivity in potassium-doped p-terphenyl, which has a close analogy with high Tc cuprate superconductors. The new approach described here is very versatile as shown by the preparation of two additional salts through systematic changing of the building blocks.