氯代脱氧松三糖的合成

本文报道由天然植物提取的松三糖为原料,在三苯基膦-四氯化碳体系进行氯代反应.结果发现氯代只发生在伯羟基上,且有较高选择性.经元素分析、IR、H-NMR、~（13）C-NMR、FAB-MS谱测定了产物结构;并通过分子模型计算作了解释.     

The terminal structure plays an important role in the biological activity of cecropin CMIV

Antibacterial peptides have received increasing attention as a new pharmaceutical substance. But the molecular mechanism of lysis is still poorly understood. CMIV gene and mutant CMIV gene in GST fusion system were expressed. After cleaving with different cleavage reagents, the peptide with an excess of N-terminus and with an un-amidated C-terminus stopped the activity while the peptide with an excess Asn at the C-terminus had the activity level the same as natural CMIV. The results showed that the terminal structure of cecropin CMIV played an important role in its biological activity.     

Low-Temperature Sodium-Ion Batteries: Challenges and Progress

As an ideal candidate for the next generation of large-scale energy storage devices, sodium-ion batteries (SIBs) have received great attention due to their low cost. However, the practical utility of SIBs faces constraints imposed by geographical and environmental factors, particularly in high-altitude and cold regions. In these areas, the low-temperature (LT) performance of SIBs presents a pressing technological challenge that requires significant breakthroughs. In LT environments, the electrochemical reaction kinetics of SIBs are sluggish, the electrode/electrolyte interface is unstable, and the diffusion of sodium ions in electrode materials is slow, leading to a decrease in battery performance. Therefore, the reasonable design of electrolyte and electrode materials is of great significance for optimizing the LT performance of SIBs. In this review, the research progress of LT SIBs electrolytes, cathode, and anode materials, as well as sodium metal batteries and solid-state electrolytes is systematically summarized in recent years, aiming to understand the design principles of LT SIBs, clarify the basic research and development of high-performance SIBs in practical applications, and promote the development of SIBs technology in the full temperature range.     

Fas stimulation induces RB dephosphorylation and proteolysis that is blocked by inhibitors of the ICE protease family

Fas antigen is a member of the tumor necrosis factor/nerve growth factor receptor family. Stimulation of Fas by Fas ligand or agonistic antibodies results in the activation of interleukin-1β converting enzyme-like (ICE-like) proteases, and proteolytic cleavage of poly(ADP-ribose) polymerase (PARP). Ultimately, Fas activation leads to apoptotic cell death. The importance of PARP cleavage to the death process remains unclear. We have hypothesized that the cleavage of other cellular substrates may be important for Fas-mediated apoptosis. Here we show that stimulation of Fas results in significant alterations of retinoblastoma protein (RB). Treatment of Jurkat cells, a human leukemic T cell line, with anti-Fas induces dephosphorylation of RB, followed by proteolytic cleavage. These events precede internucleosomal DNA fragmentation. Dephosphorylation and cleavage of RB are inhibited by a specific tetrapeptide inhibitor of ICE-like proteases or by expression of cowpox virus CrmA protein or the Bcl-2 oncoprotein. Inhibition of these RB changes correlates with inhibition of apoptosis. We propose that cleavage of RB may represent an important step in the pathway of Fas-mediated apoptotic cell death. J. Cell. Biochem. 64:586–594. © 1997 Wiley-Liss, Inc.