木薯果胶甲基酯酶抑制因子MePMEI1的生物信息学分析

为探讨木薯MePMEI1的分子结构特征。通过PCR扩增和测序技术及生物信息学分析工具对木薯MePMEI1基因进行克隆、测序及相关生物信息学分析。结果表明木薯MePMEI1基因编码区全长609 bp,编码202个氨基酸残基;MePMEI1基因编码蛋白分子量21.78 k D,理论等电点(pI)约为5.51;生物信息学预测发现,木薯MePMEI1蛋白是稳定的亲水蛋白;具有跨膜区为分泌蛋白;含有1个PMEI结构域,1个糖基化位点,31个磷酸化位点;二、三级结构以α螺旋和无规则卷曲为主。该蛋白的生物功能可能与细胞被膜、酶和生长因子等相关。木薯MePMEI1基因的生物信息学分析为进一步研究其遗传特性和生理生化机制提供了理论依据。     

重组TFPI缺失突变体TFPI1-161在毕赤酵母中的高效表达及功能鉴定

人组织因子途径抑制物(TFPI)是一种体内天然存在的外源性凝血途径特异性抑制物。缺失突变体TFPI1-161包括TFPI的N末端、K1和K2结构域,是一种研究TFPi结构与功能及其相互关系的理想对照分子。以克隆质粒pGEM-3Zf(-)-TFPi为模板,用PCR方法获得TFPI1-161基因,构建表达质粒pPIC9K-TFPi1-161并转化毕赤酵母GS115。通过筛选多拷贝转化子及优化发酵培养条件,首次在毕赤酵母中高效表达了TFPI1-161经纯化后最终产量高于酿酒酵母20倍以上。由于糖基化程度不同,TFPI1-161表达为TFPI1-161(24kD)和TFPI1-161(27kD)两种分子形式,其等电点分别为4、8和4．9。根据等电点差异,二可通过阴离子交换层析得到分离,其活性无显性差异。经分子筛和阴离子交换层析分离纯化后,从4L发酵培养液中可分别获得1.4g TFPI1-161(24kD)和1.8gTFPI1-161(27kD),其比活性分别达12880u／mg和12400u／mg,回收率达55％。经稀释的凝血酶原时间及发色底物法检测,重组TFPI1-161具有良好的抗凝及抑制FXa活性的作用。为获得大量TFPI1-161提供了一种廉价高效的蛋白表达纯化方式,为进一步的基础及临床前研究奠定了基础。     

Peptide models of four possible insulin folding intermediates with two disulfides

The single-chain insulin (PIP) can spontaneously fold into native structure through preferred kinetic intermediates. During refolding, pairing of the first disulfide A20-B19 is highly specific, whereas pairing of the second disulfide is likely random because two two-disulfide intermediates have been trapped. To get more details of pairing property of the second disulfide, four model peptides of possible folding intermediates with two disulfides were prepared by protein engineering, and their properties were analyzed. The four model peptides were named [A20-B19, A7-B7]PIP, [A20-B19, A6-B7]PIP, [A20-B19, A6-A11]PIP, and [A20-B19, A7-A11]PIP according to their remaining disulfides. The four model peptides all adopt partially folded structure with moderate conformational differences. In redox buffer, the disulfides of the model peptides are more easily reduced than those of the wild-type PIP. During in vitro refolding, the reduced model peptides share similar relative folding rates but different folding yields: The refolding efficiency of the reduced [A20-B19, A7-A11]PIP is about threefold lower than that of the other three peptides. The present results indicate that the folding intermediates corresponding to the present model peptides all adopt partially folded conformation, and can be formed during PIP refolding, but the chance of forming the intermediate with disulfide [A20-B19, A7-A11] is much lower than that of forming the other three intermediates.     

SFTSV infection in rodents and their ectoparasitic chiggers

SFTSV, a tick-borne bunyavirus causing a severe hemorrhagic fever termed as severe fever with thrombocytopenia syndrome (SFTS). To evaluate the potential role of rodents and its ectoparasitic chiggers in the transmission of SFTSV, we collected wild rodents and chiggers on their bodies from a rural area in Qingdao City, Shandong Province, China in September 2020. PCR amplification of the M and L segments of SFTSV showed that 32.3% (10/31) of rodents and 0.2% (1/564) of chiggers (Leptotrombidium deliense) from the rodents were positive to SFTSV. Our results suggested that rodents and chiggers may play an important role in the transmission of SFTSV, although the efficiency of chiggers to transmit SFTSV needs to be further investigated experimentally.     

Intercellular mitochondria transfer:a new perspective for the treatment of metabolic diseases

In the past few decades,obesity is in an increasingly prevalent metabolic disease worldwide,posing the greatest threat to human health.Understanding the pathway...     

Intercellular transmission of chronic ER stress:a new mechanism of metabolic diseases

Cell-cell communication plays a critical role in cell proliferation,dif-ferentiation,morphogenesis,functiogenesis,and tissue homoeostasis in multicellular organ...     

Galectin-3 critically mediates the hepatoprotection conferred by M2-like macrophages in ACLF by inhibiting pyroptosis but not necroptosis signalling

We previously documented that M2-like macrophages exert a hepatoprotective effect in acute-on-chronic liver failure (ACLF) by inhibiting necroptosis signalling. Nevertheless, the molecular mechanism behind this hepatoprotection still needs to be further dissected. Galectin-3 (GAL3) has been reported to be critically involved in the pathogenesis of multiple liver diseases, whereas the potential role of GAL3 in ACLF remains to be explored. Herein, we hypothesised that GAL3 plays a pivotal role in the hepatoprotection conferred by M2-like macrophages in ACLF by inhibiting necroptosis. To test this hypothesis, we first assessed the expression of GAL3 in control and fibrotic mice with or without acute insult. Second, loss- and gain-of-function experiments of GAL3 were performed. Third, the correlation between GAL3 and M2-like macrophage activation was analysed, and the potential role of GAL3 in M2-like macrophage-conferred hepatoprotection was confirmed. Finally, the molecular mechanism underlying GAL3-mediated hepatoprotection was dissected. GAL3 was found to be obviously upregulated in fibrotic mice with or without acute insult but not in acutely injured mice. Depletion of GAL3 aggravated hepatic damage in fibrotic mice upon insult. Conversely, adoptive transfer of GAL3 provided normal mice enhanced resistance against acute insult. The expression of GAL3 is closely correlated with M2-like macrophage activation. Through adoptive transfer and depletion experiments, M2-like macrophages were verified to act as a major source of GAL3. Importantly, GAL3 was confirmed to hold a pivotal place in the hepatoprotection conferred by M2-like macrophages through loss- and gain-of-function experiments. Unexpectedly, the depletion and adoptive transfer of GAL3 resulted in significant differences in the expression levels of pyroptosis but not necroptosis signalling molecules. Taken together, GAL3 plays a pivotal role in the hepatoprotection conferred by M2-like macrophages in ACLF by inhibiting pyroptosis but not necroptosis signalling. Our findings provide novel insights into the pathogenesis and therapy of ACLF.Subject terms: Inflammasome, Necroptosis