The programmed −1 ribosomal frameshifting (−1 PRF) utilized by eukaryotic RNA viruses plays a crucial role for the controlled, limited synthesis of viral RNA replicase polyproteins required for genome replication. The viral RNA replicase polyproteins of severe acute respiratory syndrome coronavirus (SARS-CoV) are encoded by the two overlapping open reading frames 1a and 1b, which are connected by a −1 PRF signal. We evaluated the antiviral effects of antisense peptide nucleic acids (PNAs) targeting a highly conserved RNA sequence on the – PRF signal. The ribosomal frameshifting was inhibited by the PNA, which bound sequence-specifically a pseudoknot structure in the −1 PRF signal, in cell lines as assessed using a dual luciferase-based reporter plasmid containing the −1 PRF signal. Treatment of cells, which were transfected with a SARS-CoV-replicon expressing firefly luciferase, with the PNA fused to a cell-penetrating peptide (CPP) resulted in suppression of the replication of the SARS-CoV replicon, with a 50% inhibitory concentration of 4.4 μM. There was no induction of type I interferon responses by PNA treatment, suggesting that the effect of PNA is not due to innate immune responses. Our results demonstrate that −1 PRF, critical for SARS-CoV viral replication, can be inhibited by CPP-PNA, providing an effective antisense strategy for blocking −1 PRF signals.

The hepatitis C virus (HCV) NS5B protein is the viral RNA-dependent RNA polymerase required for replication of the HCV RNA genome. We have identified a peptide that most closely resembles a short region of the protein kinase C-related kinase 2 (PRK2) by screening of a random 12-mer peptide library displayed on the surface of the M13 bacteriophage with NS5B proteins immobilized on microwell plates. Competitive phage enzyme-linked immunosorbent assay with a synthetic peptide showed that the phage clone displaying this peptide could bind HCV RNA polymerase with a high affinity. Coimmunoprecipitation and colocalization studies demonstrated in vivo interaction of NS5B with PRK2. In vitro kinase assays demonstrated that PRK2 specifically phosphorylates NS5B by interaction with the N-terminal finger domain of NS5B (amino acids 1-187). Consistent with the in vitro NS5B-phosphorylating activity of PRK2, we detected the phosphorylated form of NS5B by metabolic cell labeling. Furthermore, HCV NS5B immunoprecipitated from HCV subgenomic replicon cells was specifically recognized by an antiphosphoserine antibody. Knock-down of the endogenous PRK2 expression using a PRK2-specific small interfering RNA inhibited HCV RNA replication. In contrast, PRK2 overexpression, which was accompanied by an increase of in the level of its active form, dramatically enhanced HCV RNA replication. Altogether, our results indicate that HCV RNA replication is regulated by NS5B phosphorylation by PRK2. The hepatitis C virus (HCV)1 is a major cause of non-A and non-B hepatitis, leading to liver cirrhosis and hepatocellular carcinoma (1, 2). HCV is an enveloped virus with a positive stranded RNA genome of ϳ9.6 kb belonging to the Hepacivirus genus in the Flaviviridae family (3). The HCV viral genome encodes a single polyprotein of ϳ3,010 amino acids, which is proteolytically processed by a combination of host and viral proteases into at least 10 distinct structural and nonstructural proteins. The structural proteins include C, E1, E2, and p7, and the nonstructural (NS) proteins include NS2, NS3, NS4A, NS4B, NS5A, and NS5B (4, 5). Among the nonstructural proteins, HCV NS5B is an RNA-dependent RNA polymerase (RdRp) that is important for replication of the HCV RNA genome (6 -8). This protein contains motifs shared by all RdRps and possesses the finger, palm, and thumb subdomains (9 -12). HCV NS5B is anchored to the endoplasmic reticulum through the C-terminal domain of 21 hydrophobic amino acids (13-15) and forms a putative HCV RNA replicase complex with other viral NS proteins (16 -19).Many cellular enzymes involved in DNA and RNA metabolism, such as DNA polymerase ␣, topoisomerase II␣, and DNAdependent RNA polymerase I and II, are phosphoproteins, and their functions are known to be regulated by cellular kinase mediated-phosphorylation (20 -26). Several viral RdRps are also modified by phosphorylation. Dengue virus type-2 RNA polymerase is phosphorylated at a serine residue by casein kinase II. Phosphorylation of this polymerase regulates interaction...

Sulfur has been explored as a cathode active material for post rechargeable batteries because of their various attractive features such as their high theoretical specific capacity which is more than six times that of typical Li‐ion battery (LIB) cathode materials (LiCoO2). Furthermore, as a by‐product of the oil refining process, it is abundant and inexpensive. Despite this, the low electrical conductivity of sulfur and the polysulfide shuttle effect in ether‐based electrolytes has become a major obstacle to the industrialization of lithium‐sulfur (Li−S) batteries. Among them, the polysulfide shuttle effect is the critical limitation to be solved and thus many researchers have been engaged in its solution. This work summarizes a variety of metal sulfide catalysts that have recently attracted attention as additives. In addition, a brief description of the metal sulfides interprets their ability to anchor polysulfides via surface polarity and to act as an electrocatalyst during polysulfide redox reactions. We describe the electrocatalytic activity and anchoring effect of metal sulfides in Li−S batteries and their future possibilities.

IPMC (ionic polymer metal composite) is composed of ionic polymer and metal electrodes on both surfaces of the polymer. In this study, we changed the surface morphology of the ionic polymer by using plasma treatment. Plasma treatment made needle-shaped microstructures on the surface of the polymer and the microstructures helped to form a thicker uniform metal electrode which is deposited by electroless plating on both sides of the polymer. We observed the actuating properties of IPMC such as displacement, force and lifetime by using the laser displacement measurement system and the load cell. Then we evaluated the enhanced characteristics of an IPMC actuator. Oxygen (the chemical etching gas) and argon (the physical etching gas) were used as the plasma source gas and the oxygen plasma resulted in higher performance.