Upgrading heterogeneous Ni catalysts with thiol modification.

Precious metal catalysts are the cornerstone of many industrial processes. Replacing precious metal catalysts with earth-abundant metals is one of key challenges for the green and sustainable development of chemical industry. We report in this work a surprisingly effective strategy toward the development of cost-effective, air-stable, and efficient Ni catalysts by simple surface modification with thiols. The as-prepared catalysts exhibit unprecedentedly high activity and selectivity in the reductive amination of aldehydes/ketones. The thiol modification can not only prevent the deep oxidation of Ni surface to endow the catalyst with long shelf life in air but can also allow the reductive amination to proceed via a non-contact mechanism to selectively produce primary amines. The catalytic performance is far superior to that of precious and non-precious metal catalysts reported in the literature. The wide application scope and high catalytic performance of the developed Ni catalysts make them highly promising for the low-cost, green production of high-value amines in chemical industry.

Porcine reproductive and respiratory syndrome virus inhibition of interferon-ß transcription by IRF3-independent mechanisms in MARC-145 cells in early infection.

Interferon ß is an important antiviral molecule whose expression is triggered through recognition of viral components by pattern recognition receptors via a cascade of signaling molecules, while viruses could target these molecules to evade from innate immunity. IFN regulatory factor 3 (IRF3) plays a crucial role in innate immune responses. Here, we demonstrate that PRRSV infection did not induce IFN-ß gene transcription in MARC-145 cells, but inhibited poly (I:C) stimulated IFN-ß gene transcription instead. Such inhibition is time-dependent with the progression of PRRSV infection. We also show that the inhibition of IFN-ß transcription in the early stage of infection could not be due to inhibition of phosphorylation and nuclear translocation of IRF3, though significant decrease of p-IRF3 and its nuclear translocation in PRRSV-infected and poly (I:C) cells was observed later at 48 h post-infection. The different patterns of inhibition for IFN-ß transcription and IRF3 phosphorylation have important implications as to the mechanism(s) by which PRRSV suppresses the type I IFN signaling at early stage of infection. There could be mechanism(s) other than effecting on IRF3 or molecules upstream that require further investigation.

Functional characterization of porcine LSm14A in IFN-ß induction.

Human LSm14A has recently been found as a processing body-associated sensor of intracellular viral nucleic acids and triggers signaling for type I IFN expression. Here porcine LSm14A (pLSm14A) was cloned from the PK-15 cells. The pLSm14A ORF is 1392 bp in length, encoding 463 amino acids. The putative pLSm14A contains a Sm-like domain and two arginine-glycine-glycine (RGG) boxes. The pLSm14A has high identity at the amino acid level to those of bovine, human and mouse (93.5-97.4%) and is transcribed in different tissues of pigs. In HEK293 or Marc-145 cells, pLSm14A was localized in the cytosol as P-body-like dots. Expression of pLSm14A in HEK293 or Marc-145 cells enhanced activities of IFN-ß and NF-κB promoters, induced IFN-ß transcription, and potentiated poly(I:C)-induced IFN-ß promoter activation, indicating that pLSm14A is a potential signal molecule in the IFN-ß pathway of pigs. We also found that pLSm14A-induced IFN-ß promoter activity was down-regulated by porcine reproductive and respiratory syndrome virus infection in Marc-145 cells. Since pLSm14A is constitutively expressed in virtually all tissues, more research is needed to explore its role in initial phase of viral infections of pigs and its relationship with RIG-I in sensing PAMPs for type I IFN induction.