Progress in the development and application of plant-based antiviral agents

Plant virus disease is one of the major causes of biological disasters in agriculture worldwide. Given the complexity of transmission media and plant disease infection mechanisms, the prevention and control of plant viral diseases is a great challenge, and an efficient green pesticide is urgently needed. For this reason, when developing candidate drug leads to regulate plant viruses, pesticide experts have focused on characteristics such as low pesticide resistance, eco-friendliness, and novel mechanism. Researchers have also theoretically investigated the molecular targets of viruses infecting agricultural crops. Antiviral screening models have been constructed based on these molecular targets, and the mechanisms of commercial drugs and high-activity compounds have been extensively investigated. After screening, some compounds have been applied in the field and found to have good commercial prospects; these drugs may be used to create new green antiviral pesticides to control plant viruses. This paper reviews the screening, mode of action, development and application of recently used plant-based antiviral agents.     

Antiviral effect of guanidine

It has been found that soluble guanidine salts show an antiviral effect on poliovirus and on some other enteroviruses. The activity was first detected in a cell culture screening system when the guanidine salt of hydroxyaminomethylene malononitrile inhibited the cytopathic effect of poliovirus in cell cultures. The studies were extended to various in vivo experiments in which the suggestive therapeutic activity of guanidine salts was again observed in monkeys infected with poliovirus. While these drugs cannot be considered for use in human disease because of severe toxicity, it is significant that potential antiviral compounds detected by the cell culture test show in vivo activity and point to the validity of such direct chemotherapeutic trials.     

Suppression of HIV infection in AZT-treated SCID-hu mice

The SCID-hu mouse, engrafted with human hematolymphoid organs, is permissive for infection with the human immunodeficiency virus (HIV). This mouse model was used to test compounds for antiviral efficacy. Two weeks after infection with HIV, 100 percent (40/40) of SCID-hu mice were positive for HIV by the polymerase chain reaction. When first treated with 3'-azido-3'-deoxythymidine (AZT), none (0/17) were HIV-positive by this assay. However, AZT-treated SCID-hu mice did have a few infected cells; after AZT treatment was stopped, viral spread was detected by polymerase chain reaction in such mice. Thus, the SCID-hu mouse provides a means to directly compare new antiviral compounds with AZT and to further improve antiviral efficacy.     

三萜与苦木味素类天然产物抗马铃薯Y病毒的活性研究

采用适时荧光定量聚合酶链式反应技术,以培育2个月的普通烟草为材料,对从药用植物苦楝中分离得到的8种三萜类成分与从臭椿中分离得到的7种苦木味素类成分进行抗马铃薯Y病毒的活性研究,结果表明：（1）3个三萜类成分(methylkulonate, dubionel B, isotoosendanin)与3个苦木味素萜类成分(ailanthone, chaparrinone, shinjudilactone)显示出比较强的抗病毒活性;（2）三萜类成分结构中C-20位的羧基与C-16位的羟基为活性基团;（3）苦木味素萜类成分结构中A环的α,β-不饱和酮为活性必需基团,此外C-15位酯基侧链的引入可增强活性。该研究对这15种天然产物来说为首次进行抗马铃薯Y病毒的报道,其构效关系的研究可为新型抗植物病毒药物的设计提供信息。     

Inhibition of hepatitis B virus replication by drug-induced depletion of nucleocapsids

Chronic hepatitis B virus (HBV) infection is a major cause of liver disease. Only interferon-alpha and the nucleosidic inhibitors of the viral polymerase, 3TC and adefovir, are approved for therapy. However, these therapies are limited by the side effects of interferon and the substantial resistance of the virus to nucleosidic inhibitors. Potent new antiviral compounds suitable for monotherapy or combination therapy are highly desired. We describe non-nucleosidic inhibitors of HBV nucleocapsid maturation that possess in vitro and in vivo antiviral activity. These inhibitors have potential for future therapeutic regimens to combat chronic HBV infection.     

资源植物红景天研究综述

对资源植物红景天的化学成份、新药理学作用研究进行了归纳分析，并对其开发利用过程中遇到的问题及相应对策进行了讨论。目前国内外已对20多种红景天的化学成分进行了研究及预试工作，分离出了9大类，40多种化学成份。红景天新的药理学作用研究发现，其具有显著的抗衰老、抗缺氧、抗不良刺激、抗病毒及肿瘤、抗疲劳和对机体双向调节等新的作用机制。红景天研究过程中存在着其生殖生理学特性引起的濒危状况、红景天资源研究系统性较差和开发与利用过程中存在着利用与生态环境保护的矛盾。针对这些问题，提出构建红景天种质资源库，选择质量性状指标进行资源筛选工作，及其采用现代生物技术手段建立最优化的红景天引种驯化群体，作为开发利用的基础。     

ANTIVIRAL EFFECTS OF BACTERIOCIN AGAINST ANIMAL-TO-HUMAN TRANSMITTABLE MUTATED SARS-COV-2: A SYSTEMATIC REVIEW

• Identification of bacteriocin sources• Classification of bacteriocins• Antiviral pathways of bacteriocinsThe COVID-19 infections caused by SARS-CoV-2 have resulted in millions of people being infected and thousands of deaths globally since November 2019. To date, no unique therapeutic agent has been developed to slow the progression of this pandemic. Despite possessing antiviral traits the potential of bacteriocins to combat SARS-CoV-2 infection has not been fully investigated. This review summarizes the mechanisms by which bacteriocins can be manipulated and implemented as effective virus entry blockers with infection suppression potential properties to highly transmissible viruses through comprehensive immune modulations that are potentially effective against COVID-19. These antimicrobial peptides have been suggested as effective antiviral therapeutics and therapeutic supplements to prevent rapid virus transmission. This review also provides a new insight into the cellular and molecular alterations which have made SARS-CoV-2 self-modified with diversified infection patterns. In addition, the possible applications of antimicrobial peptides through both natural and induced mechanisms in infection prevention perspectives on changeable virulence cases are comprehensively analyzed. Specific attention is given to the antiviral mechanisms of the molecules along with their integrative use with synthetic biology and nanosensor technology for rapid detection. Novel bacteriocin based therapeutics with cutting-edge technologies might be potential substitutes for existing time-consuming and expensive approaches to fight this newly emerged global threat.     

Microbial degradation of halogenated compounds

The mode of degradation of various halogenated compounds in isolated pure cultures and the disposition of the degradative genes have been studied. In many cases the degradative genes are found to be clustered on plasmids and appear to be under positive control. Genetic selection in vivo and genetic manipulations in vitro have allowed construction of strains having wider biodegradative potentials than their natural counterparts. Molecular cloning of the degradative gene clusters for halogenated compounds in vectors with a broad host range also allows the transfer of such genes to a large number of Gram-negative bacteria. The application of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T)-degrading microorganisms has demonstrated the effectiveness of this strain in removing large amounts of 2,4,5-T from contaminated soil within a short period, and such soil has been shown to support the growth of plants normally sensitive to low concentrations of 2,4,5-T. The two major challenges that must be addressed in the near future are the development of appropriate microbial technology for the decontamination of soil containing hazardous halogenated compounds, and the promulgation of appropriate regulations to ensure the safety and well-being of the public during the application of genetically improved strains in an open environment.     

Inhibitors of strand transfer that prevent integration and inhibit HIV-1 replication in cells

Integrase is essential for human immunodeficiency virus-type 1 (HIV-1) replication; however, potent inhibition of the isolated enzyme in biochemical assays has not readily translated into antiviral activity in a manner consistent with inhibition of integration. In this report, we describe diketo acid inhibitors of HIV-1 integrase that manifest antiviral activity as a consequence of their effect on integration. The antiviral activity of these compounds is due exclusively to inhibition of one of the two catalytic functions of integrase, strand transfer.     

Complete replication of hepatitis C virus in cell culture

Many aspects of the hepatitis C virus (HCV) life cycle have not been reproduced in cell culture, which has slowed research progress on this important human pathogen. Here, we describe a full-length HCV genome that replicates and produces virus particles that are infectious in cell culture (HCVcc). Replication of HCVcc was robust, producing nearly 10(5) infectious units per milliliter within 48 hours. Virus particles were filterable and neutralized with a monoclonal antibody against the viral glycoprotein E2. Viral entry was dependent on cellular expression of a putative HCV receptor, CD81. HCVcc replication was inhibited by interferon-alpha and by several HCV-specific antiviral compounds, suggesting that this in vitro system will aid in the search for improved antivirals.     

丹参酚酸类成分生物合成途径研究进展

酚酸类成分是丹参的一大类活性成分,具有重要的生理意义,从丹参酚酸类成分的生理活性、生源途径、生源途径关键酶基因研究等方面进行了归纳总结,提出了有待深入研究解决的问题,为丹参酚酸成分的生物合成及其调控研究奠定基础。     

Bacterial small-molecule signaling pathways

Bacteria use diverse small molecules for extra- and intracellular signaling. They scan small-molecule mixtures to access information about both their extracellular environment and their intracellular physiological status, and based on this information, they continuously interpret their circumstances and react rapidly to changes. Bacteria must integrate extra- and intracellular signaling information to mount appropriate responses to changes in their environment. We review recent research into two fundamental bacterial small-molecule signaling pathways: extracellular quorum-sensing signaling and intracellular cyclic dinucleotide signaling. We suggest how these two pathways may converge to control complex processes including multicellularity, biofilm formation, and virulence. We also outline new questions that have arisen from recent studies in these fields.     

多花蔷薇花挥发油化学成分的GC／MS分析

本文采用ＧＣ／ＭＳ技术，分析了经并时蒸馏萃取装置获得的多花蔷薇挥发油化学成分。共鉴定出２８种化合物，为开发、利用这一野生资源提供了科学依据。     

玉米胚乳发育研究进展

综述了玉米胚乳发育研究进展,阐述了胚乳细胞分裂增殖、充实过程及影响因素,分析了胚乳细胞发育与粒重的关系,探讨了胚乳形成的调控机制,并提出了存在的问题和需要解决的问题。     

在高等数学教学中引入数学建模思想的探索与实践

在高等数学教学中引入数学建模思想,将数学思想和数学方法的作用展示给学生,激发学生学习高等数学的兴趣和积极性,提高高等数学的教学质量.在高等数学教学中引入数学建模案例要遵循循序渐进、逐步深入的原则,随着课程的进展选择适合学生水平的建模案例.本文用范例形式介绍在高等数学教学中引入数学建模思想的探索与实践.     

Permethylpolysilanes: Silicon Analogs of Hydrocarbons: Cyclic polysilanes resemble aromatic hydrocarbons in electronic and chemical properties

Studies of the spectra of cyclopolysilanes have led to several significant conclusions. These molecules possess both easily ionized Si-Si bonding electrons and low energy delocalized antibonding orbitals, and can therefore serve either as electron donors or acceptors. This model explains the similarity in properties between cyclopolysilanes and aromatic hydrocarbons. Further investigations of cyclopolysilanes seem likely to provide the key to understanding of controversial questions of bonding in metalloid compounds even as studies of their carbon analogs, the cyclic and cage hydrocarbons, have been crucial to present knowledge of organic stereochemistry and reaction mechanisms. The reactions of cyclopolysilanes are not only interesting in themselves, but have opened the way to the synthesis of complex polysilanes and thus to whole new areas of study. Improved methods of synthesis and isolation are needed, but the number and kinds of compounds that can be prepared seem almost limitless. Perhaps a polymetal chemistry comparable in breadth and variety to carbon chemistry is now developing.     

Some marine ecological phenomena: chemical basis and biomedical potential

Analysis of secondary metabolites derived from marine organisms has revealed a broad spectrum of novel molecular architecture. The function of these compounds in their natural habitat is linked to various aspects of species survival, and the compounds have also served as characteristic chemical markers through successive trophic levels. Fundamental questions concerning the locus of synthesis in complex and intricate assemblies of plants and animals and the pathways of biosynthesis are beginning to be answered. It is now apparent that the marine environment gives rise to some distinctive chemistry, which is generated along characteristic pathways. Some of the newly described compounds have already become valuable tools in biomedicine.     

Anticonvulsant medications extend worm life-span

Genetic studies have elucidated mechanisms that regulate aging, but there has been little progress in identifying drugs that delay aging. Here, we report that ethosuximide, trimethadione, and 3,3-diethyl-2-pyrrolidinone increase mean and maximum life-span of Caenorhabditis elegans and delay age-related declines of physiological processes, indicating that these compounds retard the aging process. These compounds, two of which are approved for human use, are anticonvulsants that modulate neural activity. These compounds also regulated neuromuscular activity in nematodes. These findings suggest that the life-span-extending activity of these compounds is related to the anticonvulsant activity and implicate neural activity in the regulation of aging.     

泛素化修饰在RLR信号通路中的研究进展

病毒入侵后被细胞的模式识别受体RIG-I样受体(RIG-I-like receptor, RLR)识别从而启动抗病毒RLR信号通路的激活,先天免疫反应的异常激活将导致慢性炎症和免疫器官损伤,甚至引起自身免疫性疾病。为了防止抗病毒信号过早激活或过度激活,机体建立了完善的调节系统防止信号传导过程发生紊乱。蛋白的翻译后修饰(Post-translational modification, PTM)是调节模式识别受体及其下游信号蛋白稳定性和活性的关键机制,而泛素化(Ubiquitination, UB)作为蛋白质翻译后修饰的重要部分在抗病毒信号通路中被广泛研究。其中K48和K63连接的泛素化最为常见,通过K48连接的泛素链能够引起靶蛋白通过蛋白酶体途径降解,而K63连接的泛素链能够促进蛋白激活和细胞信号转导。RIG-I、MAVS、TBK1以及TRAF家族相关蛋白作为RLR通路的信号传递分子,其蛋白的泛素化修饰也成为研究的重点。本文讨论了K48和K63泛素化在抗病毒免疫信号通路中的研究进展,特别是RIG-I样受体引发的信号传导途径中蛋白的泛素化修饰。     

Infectious diseases. Polio outbreak raises questions about vaccine

A small cluster of polio cases in the Dominican Republic and Haiti marks both the first polio outbreak in the Western Hemisphere in more than 9 years and the first reliable report that a vaccine-derived polio strain may have reverted to a virulent form and spread contagiously. Although a massive vaccination campaign already in the works is expected to contain the outbreak, the unusual incident raises troubling questions about a vaccine that has been in widespread use for nearly 40 years.