Expression of antimicrobial peptide Cecropin P1 in Saccharomyces cerevisiae and its antibacterial and antiviral activity in vitro

BackgroundCecropin P1, acting as an antimicrobial, has a broad-spectrum antibacterial activity with some antiviral and antifungal properties. It is a promising natural alternative to antibiotics which is originally isolated from the pig intestinal parasitic nematode Ascaris suum. Many studies have shown that Cecropin P1 is helpful for the prevention or treatment of clinical diseases. Therefore, it is very necessary to establish a safe, nontoxic, and efficient expression method of Cecropin P1.ResultsThe results indicated that the recombinant protein was about 5.5 kDa showed by Tricine–SDS–PAGE and Western blot. And Cecropin P1 was efficiently secreted and expressed after 12 h of induction, with an increasing yield over the course of the induction. Its maximum concentration was 7.83 mg/L after concentration and purification. In addition, in vitro experiments demonstrated that Cecropin P1 not only exerted a strong inhibitory effect on Escherichia coli, Salmonella sp., Shigella sp., and Pasteurella sp., but also displayed an antiviral activity against PRRSV NADC30-Like strain.ConclusionsCollectively, the strategy of expressing Cecropin P1 in Saccharomyces cerevisiae is harmless, efficient, and safe for cells. In addition, the expressed Cecropin P1 has antiviral and antibacterial properties concurrently.How to cite: Jiang R, Zhang P, Wu X, et al., Expression of antimicrobial peptide Cecropin P1 in Saccharomyces cerevisiae and its antibacterial and antiviral activity in vitro. Electron J Biotechnol 2021;50. https://doi.org/10.1016/j.ejbt.2020.12.006     

基于系统性文献回顾法的新型研发机构研究与展望

本文以国内经济管理领域 2003年至2019 年的179篇文献为样本,使用系统性文献回顾法(SLR),探索和总结了新型研发机构的研究现状及其知识结构,分析现有研究的缺失并尝试寻找未来的研究趋势。研究发现: 第一,新型研发机构的知识结构由9个部分构成一个2W1H的主题研究框架。第二,从国家、产业和企业层面分别总结了阻碍新型研发机构发展的因素及其提升对策建议。第三,从研究知识模块、研究切入角度和研究趋势拓展3个方面解剖现有知识断层,并对未来的研究提出具体可行的对策建议     

大疫当前谈供应链思维：从“啤酒游戏”说起

2019年底暴发的新冠肺炎疫情是一次重大的公共卫生事件,它对我国乃至世界的社会经济都将产生巨大而深远的影响。遗憾的是,这样的事件已不再是百年一遇,而是十年一遇或更短的时间,因此如何有效地应对大规模传染性疾病的暴发是人类社会面临的十分重要而迫切的问题。这次新冠肺炎疫情既是一个不幸,也是一个难得的学习机会。通过对疫情防控过程的回顾,以及对在该过程中所遇到的一些困难的梳理,发现很多问题最终都可以归结为供需矛盾的问题,而供给侧的挑战通常又都源于供应链的无序和混乱。文章结合现代供应链管理理论的一些基本原理,对疫情防控工作进行了分析并给出了建议,如建立全国联网传染病监测中心、国家防控战略物资安全库存、国家突发事件应急管理指挥中心等。另外,疫后经济重建也至关重要,因此还从供应链思维的角度,分析了新冠肺炎疫情的行业影响,以及企业复工复产过程中应该注意的事项。     

基于OBE理念的线上教学实践探索及后疫情时代思考——以“测控仪器设计”课程为例

为抗击新冠肺炎疫情,我国开启了"停课不停学"大规模线上教学实践。该文以"测控仪器设计"课程为例,积极开展了基于OBE理念的线上教学重构设计,从教学目标、教学内容、教学方法、质量监控、评价体系、持续改进等方面进行了实践探索。基于线上教学的实践探索和教学反思,提出了后疫情时代教师发展和教学改革的新思路。     

COVID-19, digital privacy,and the social limits on data-focused public health responses

The implementation of digital contact tracing applications around the world to help reduce the spread of the COVID-19 pandemic represents one of the most ambitious uses of massive-scale citizen data ever attempted. There is major divergence among nations, however, between a “privacy-first” approach which protects citizens’ data at the cost of extremely limited access for public health authorities and researchers, and a “data-first” approach which stores large amounts of data which, while of immeasurable value to epidemiologists and other researchers, may significantly intrude upon citizens’ privacy. The lack of a consensus on privacy protection in the contact tracing process creates risks of non-compliance or deliberate obfuscation from citizens who fear revealing private aspects of their lives – a factor greatly exacerbated by recent major scandals over online privacy and the illicit use of citizens’ digital information, which have heightened public consciousness of these issues and created significant new challenges for any collection of large-scale public data. While digital contact tracing for COVID-19 remains in its infancy, the lack of consensus around best practices for its implementation and for reassuring citizens of the protection of their privacy may already have impeded its capacity to contribute to the pandemic response.     

基于灰色系统理论的重庆自驾游可行性分析

自驾游是早年流行于欧美等发达国家的旅游形式,近年来越来越多的人喜欢并加入到这种旅游活动中来,使得自驾游成为一种时尚。中国是发展中国家,整体经济发展水平不高,使得大众自驾游还不能实现。利用灰色系统GM（1,1）模型,通过对影响重庆自驾游的经济因素进行分析,预测农村居民人均收入、农村居民恩格尔系数、农村居民出游率、城镇居民人均可支配收入、城镇居民恩格尔系数、城镇居民出游率,进而分析重庆实现大众自驾游的可行性,为重庆旅游业的发展提供科学理论依据。     

MTT法测定八种中草药体外抗肺癌细胞SPC-A1活性

[目的]建立一套高效、快速的体外中草药抗肺癌活性物质筛选模型。[方法]采用MTT法,对芸香草、地榆、甘草、柴胡、莪术、蜜蒙花、半边莲和旱芹等8种中草药体外抗肺癌细胞SPC-A1的活性进行检测。分析肿瘤细胞生长曲线,观察倒置显微镜下肺癌细胞在不同阶段的生长状况。[结果]在中草药活性物质作用下细胞尽管仍然贴壁,但出现萎缩及边缘清晰化,与生长状况良好的细胞形态区别明显。浓度为1.5mg/ml的莪术乙醇浸提液（ESCC）和甘草乙醇浸提液（ESCG）对体外培养的肺癌细胞SPC-A1有较强的抑制增殖作用,抑制率分别为：52.9%和51.6%,且抑制作用随着浓度的加大而加强。[结论]MTT法筛选可作为8种中草药抗肺癌细胞的一个基本筛选模型。     

浅谈约翰·福尔斯的《幻想》：一部奇特的玄学侦探小说

约翰·福尔斯的最后一部小说《幻想》自从问世以来一直被评论界和读者所忽略。事实上,这部小说是一部奇特的玄学侦探小说。它具有玄学侦探小说的基本特征,既是悬而未决的迷案小说又是自反小说,从内容和形式上均反映出作者的“失踪”创作理论。     

概率布尔网络的动态行为研究

概率布尔网络是布尔网络的拓展。布尔网络和概率布尔网络已经广泛应用于生物系统模拟中。运用马尔科夫链模拟概率布尔网络的动态行为及采用消除趋势波动分析（DFA）方法,分析概率布尔网络的长程相关性特性发现,概率布尔网络的动态行为具有长程相关性,大部分概率布尔网络能呈现1/f波动,且产生1/f波动的噪声值和范围比布尔网络的大。     

为湖湘文化把脉——读谢发平先生的《湖湘文化十九讲》

谢发平先生的《湖湘文化十九讲》不仅是一本“讲”湖湘文化的书,也是一部宣扬湖湘文化,彰显湖南人精神的力作。该书在“回望”之中,展现出宏大的视野,将对历史的穿透力与对现实的敏锐感知有机结合起来,在品评历史人物和地方风物的基础上,为湖南人文、经济和社会发展建言献策,奉献良方。