新型抗病毒剂病毒星的创制研究

介绍了新型抗病毒剂病毒星的整个研究开发过程,系统讨论了先导化合物的发现,生物活性的评价,毒理学试验结果,分析方法以及作用机理方面的研究结果,为达到新农药临时登记奠定了基础,有望进入产业化开发.

病毒星表观油水分配系数的测定

[目的]在建立水中病毒星的残留分析方法的基础上,测定病毒星在正辛醇-水中的表观油水分配系数。[方法]采用HPLC法测定病毒星的质量浓度,用摇瓶法测定病毒星在正辛醇-水中的表观油水分配系数。[结果]病毒星在0.05、0.11、1.13 mg/kg质量分数下的平均添加回收率为98.3%、98.4%、91.5%,变异系数为2.2%~3.9%。[结论]摇瓶法测得病毒星在二次蒸馏水中的平均lgKow为3.08。

Study on Microsatellite Distribution in Complete Genomes of Tobacco Vein Clearing Virus

MATLAB software and optimal complete subgraph algorithm were used to extract and reveal the microsatellite distribution features in the complete genomes of the tobacco vein clearing virus （NC-003 378.1） from the NCBI database.The results showed that the repetitions number and their location of the N-base group has been extracted and displayed.The largest repetitions of N-base group in the complete genomes of the tobacco vein clearing virus was decreased as the exponential function with the increasing of N.The method used in this study could be applied to the extraction and revealing of the microsatellite distribution features in the complete genomes of other viruses,thereby provided a basis for the research of the structure and the law of function,inheritance and variation by the using of the microsatellite distribution features.

Emergence of a new satellite RNA from cucumber mosaic virus isolate P1

The cucumber mosaic virus (CMV) isolate P1 caused very mild symptoms on many plant species. After serial passages by mechanical inoculation over five years, CMV P1 caused severe symptoms on several tobacco cultivars and tomato. A specific band of approximately 0.3 kb in length was amplified by RT PCR with primers synthesized based on reported CMV satellite RNA (satRNA) sequences. Sequence analysis showed there were two satRNAs (Sat P1 1 and Sat P1 2). Sat P1 1 contained 335 nucleotides, and Sat P1 2 contained 394 nucleotides. These two satRNAs shared 64% overall nucleotide sequence homology, and differences between the two satRNAs included mutations as well as deletions. Sat P1 1 was identical to a satRNA (Z96099) reported in 1995 in CMV P1. Based on differences in the sequence and secondary structure between these two satRNAs, we conclude that Sat P1 2 represents the emergence of a new satellite (necrotic satellite) from attenuated satRNA populations. The possible effect of the emergence of this new satRNA is discussed.

Expression and Assembly Mechanism of the Capsid Proteins of a Satellite Virus (XSV) Associated with Macrobrachium rosenbergii Nodavirus

The extra small virus （XSV） is a satellite virus associated with Macrobrachium rosenbergii nodavirus （MrNV） and its genome consists of two overlapping ORFs, CP17 and CP16. Here we demonstrate that CP16 is expressed from the second AUG of the CP17 gene and is not a proteinase cleavage result of CP17. We further expressed CP17 and several truncated CP17s （in which the N-or C-terminus or both was deleted）, respectively, in Escherichia coli. Except for the recombinant plasmid CP17^AC10, all recombinant plasmids expressed soluble protein which assembled into virus-like particles （VLPs）, suggesting that the C-terminus is important for VLP formation.

The complete genomic sequence analysis of genotype 4 human astrovirus HASTVgz01 strain in Guangzhou

To analyze the genomic molecular structure and genotype of human astrovirus isolated from infant in Guangzhou of China, the primers were designed based on the genomic sequence of astrovirus from the C, enBank and the target sequence were amplified by RT-PCR. Then the PCR-products were cloned to T vector and sequenced. The genomic nucleotide sequences were analyzed by the programs CLUSTAL W and DNASTAR. It was found that the full genomic length of HASTVgz01 strain was 6721 bp and the ORFs were 6558 bp. The 5＇ and 3＇UTR were 82 and 81 nucleotides. The genome included 3 open reading frames （ORFs） ： ORFla, ORFlb and ORF2. The 5＇-terminal ORFla started at nueleotide 83 and extended to nucleotide 2845. ORFlb （nt 2785 to nt 4332） overlaped ORFla by 61 nueleotides. The 3＇-terminal ORF2 began at nucleotide 4325 and terminated at nucleotide 6640. ORF2 had 2316 nucleotides. Compared with other astrovirus sequences in GenBank, the homology of the amino acid sequence of ORF2 of HASTVgz01 strain with that of serotype 4 was 93%. Homology with other serotypes ranged from 61% to 70%. The complete nucleotide sequence of astrovirus HASTVgz01 strain isolated from Guangzhou in China was 6721 bp in length, GenBank accession NO. DQ344027. Comparing the ORF2 of astrovirus HASTVgz01 with the known sequences of types 1-8 the highest homology was serotype 4 （93%）. Comparative sequence analysis of the HASTVgz01 ORF2 with the reported human astrovirus sequences revealed that the isolated astrovirus belongs to genotype （serotype） 4.

Cyclovirobuxine D inhibits dengue virus replication by impeding the complete autophagy in a cholesterol-dependent manner

Dengue virus(DENV)is the most common mosquito-borne flavivirus,and it affects millions of people globally every year.Currently,there are no approved drugs for the treatment of dengue infection.By screening a natural product library,we identified a novel compound,cyclovirobuxine D(Cvb D),that displays anti-DENV activity.Cvb D inhibits DENV replication in vitro in a dose-dependent manner and protects suckling mice against lethal DENV infection.Mechanistically,Cvb D regulates the expression of genes related to the cellular cholesterol pathway.As a result,Cvb D increases cellular cholesterol synthesis and accumulation,activates mTOR,and inhibits viral-dependent autophagy.Cvb D does not suppress autophagy initiation but impedes the nuclear translocation of the lysosome transcription factor TFEB.In addition,Cvb D restricts the replication of other positive-strand RNA viruses such as Zika virus and Coxsackievirus B3.We speculate that Cvb D could be a broad-spectrum antiviral drug candidate for use against positive-strand RNA viruses that require autophagy for optimal replication.