Anti-C3 polyclonal antibody

New RNA modifications are needed to advance our toolbox for targeted manipulation of RNA. In particular, the development of high-performance reporter groups facilitating spectroscopic analysis of RNA structure and dynamics, and of RNA-ligand interactions has attracted considerable interest. To this end, fluorine labeling in conjunction with F-19-NMR spectroscopy has emerged as a powerful strategy. Appropriate probes for RNA previously focused on single fluorine atoms attached to the 5-position of pyrimidine nucleobases or at the ribose 2 '-position. To increase NMR sensitivity, trifluoromethyl labeling approaches have been developed, with the ribose 2 '-SCF3 modification being the most prominent one. A major drawback of the 2 '-SCF3 group, however, is its strong impact on RNA base pairing stability. Interestingly, RNA containing the structurally related 2 '-OCF3 modification has not yet been reported. Therefore, we set out to overcome the synthetic challenges toward 2 '-OCF3 labeled RNA and to investigate the impact of this modification. We present the syntheses of 2 '-OCF3 adenosine and cytidine phosphoramidites and their incorporation into oligoribonucleotides by solid-phase synthesis. Importantly, it turns out that the 2 '-OCF3 group has only a slight destabilizing effect when located in double helical regions which is consistent with the preferential C3 '-endo conformation of the 2 '-OCF3 ribose as reflected in the (3)J (H1 '-H2 ') coupling constants. Furthermore, we demonstrate the exceptionally high sensitivity of the new label in F-19-NMR analysis of RNA structure equilibria and of RNA-small molecule interactions. The study is complemented by a crystal structure at 0.9 angstrom resolution of a 27 nt hairpin RNA containing a single 2 '-OCF3 group that well integrates into the minor groove. The new label carries high potential to outcompete currently applied fluorine labels for nucleic acid NMR spectroscopy because of its significantly advanced performance.

The aquatic ecosystem is seriously damaged because of the heavy use of pesticides and antibiotics. Fish is the indispensable link between environmental pollution and human health. However, the toxic effects of environment-related concentrations of pesticides and antibiotics in fish have not been thoroughly studied. In this study, grass carps exposed to cypermethrin (CMN, 0.651 mu g/L) or/and sulfamethoxazole (SMZ, 0.3 mu g/L) for 42 days caused oxidative stress, apoptosis and immunodeficiency in the spleen of grass carps. CMN or/and SMZ exposure led to oxidative damage (consumption of antioxidant enzymes (superoxide dismutase and catalase)) and lipid peroxidation (accumulation of malondialdehyde), induced apoptosis (increases in TUNEL index, Bax/bcl-2, p53, puma and Caspase family expression). In addition, the levels of immunoglobulin M (IgM), complement 3 (C3) were significantly decreased in all treatment groups, which trend was also found in C-reactive protein in CMN and MIX group, and lysozyme in MIX group. Transcription of almost all genes involved in the Toll-like receptors (TLR) signaling pathway was up-regulated under CMN or/and SMZ exposure. However, when subsequently attacked by Aeromonas hydrophila for 2 days, the TLR pathway was inhibited in spleens of all treatment groups accompanied by higher mortality. Overall, the environmentally relevant concentration of CMN and SMZ damages the immune system, triggering oxidative stress and apoptosis in carps. And by affecting the conduction of TLR signaling pathway, CMN or/and SMZ exposure inhibits the innate immune response of fish and reducing their disease resistance. This study highlights the importance of rational and regulated use of these pesticides and antibiotics. (C) 2020 Elsevier Ltd. All rights reserved.