在昆虫细胞中高效表达蓝舌病毒VP7蛋白作为组特异性诊断抗原

对蓝舌病毒结构蛋白ＶＰ７作为组特异性诊断抗原进行了研究,将编码ＢＴＶ１３主要组特异性抗原ＶＰ７的Ｓ７ｃＤＮＡ插入杆状病毒表达载体ｐＦａｓｔＢａｃ１,通过同源重组获得了重组杆状病毒ｅｖＢａｃＢＴＶＰ７。用此重组病毒感染昆虫细胞获得ＶＰ７蛋白的高效表达,表达量可占细胞蛋白总量的１２．４％。     

Evidence that plasma membrane electrical potential is required for vesicular stomatitis virus infection of MDCK cells: A study using fluorescence measurements through polycarbonate supports

Summary We used fluorescence microscopy of Madin-Darby Canine Kidney (MDCK) cells grown on polycarbonate filters to study a possible link between plasma membrane electrical potential (_pm) and infectivity of vesicular stomatitis virus (VSV). Complete substitution of K⁺ for extracellular Na⁺blocks VSV infection of MDCK cells as well as baby hamster kidney (BHK) cells. When we independently perfused the apical and basal-lateral surfaces of high resistance monolayers, high K⁺ inhibited VSV infection of MDCK cells only when applied to the basal-lateral side; high K⁺ applied apically had no effect on VSV infection. This morphological specificity correlates with a large decrease in _pm of MDCK cells when high K⁺ buffer is perfused across the basal-lateral surface. Depolarization of the plasma membrane by 130 mm basal K⁺ causes a sustained increase of cytosol pH in MDCK cells from 7.3 to 7.5 as reported by the fluorescent dye BCECF. Depolarization also causes a transient increase of cytosol Ca²⁺ from 70 to 300 nm as reported by the dye Fura-2. Neither increase could explain the block of VSV infectivity by plasma membrane depolarization. One alternative hypothesis is that _pm facilitates membrane translocation of viral macromolecules as previously described for colicins, mitochondrial import proteins, and proteins secreted by Escherichia coli.We thank Kenneth Spring for many helpful discussions concerning fluorescence digitized imaging systems, James Russell for his collaboration in the design of our imaging system, Herbert Chase for suggestions on dye loading into MDCK cells, and Manfred Schubert and George Harmison for providing expertise on VSV.     

Variability in the transmission efficiency of potyviruses by different clones ofAphis gossypii

A sample of seventy-twoAphis gossypii Glover (Homoptera: Aphididae) clones was collected in south-eastern France. The efficiency of these clones to transmit a potyvirus (papaya ringspot virus T-strain) was assessed in controlled conditions. In a first screening, the virus was transmitted by all clones and a 3.5-fold difference between the most and least efficient clones was obtained. During subsequent trials, which were carried out to confirm the differences in the transmission efficiency of these clones, only one clone proved to be more efficient than the others. This difference appeared consistent over a 1-year period, and was also confirmed with 4 other related potyviruses.

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Résumé Un échantillon de 72 clones deA. gossypii a été collecté dans le Sud-Est de la France. L'efficacité de transmission d'un potyvirus (PRSV-T) a été mesurée en conditions contr?lées pour chacun de ces clones. Un premier screening a permis de montrer que tous les clones transmettaient ce virus, et qu'un rapport de 3,5 existait entre l'efficacité de transmission du clone le plus efficace et celle du clone le moins efficace. Au cours des essais ultérieurs destinés à confirmer ces différences, un seul clone s'est montré significativement plus efficace que les autres. Cette différence s'est maintenue pendant la période d'essais (1 an). Elle s'est reproduite avec 4 autre potyvirus apparentés.

     

Prognostic molecular markers in pediatric liver disease – Are there any?

Pediatric liver disease (PLD) is a major cause of severe morbidity and prolonged hospitalizations in children. Stratifying patients in terms of prognosis remains challenging. The limited knowledge about molecular mechanisms causing and accompanying PLD remains the main obstacle in a search for reliable prognostic biomarkers. A systematic search of MEDLINE via PubMed and Embase via OVID was conducted on studies published between August 2007 and August 2017. Molecular markers with a prognostic potential in terms of survival, need for liver transplantation or disease progression/regression were selected. In general, identified studies were single center smaller case-control studies or case series with a low level of evidence and a high risk of bias. Only 23 studies comprising 898 patients could be included, mostly focusing on biliary atresia, non-alcoholic fatty liver disease, viral hepatitis, and LT; and markers related to morphogenesis and fibrosis. Furthermore, molecular markers in metabolic pathways and inflammation shown to be relevant, however requiring further validation. Hence, further biological and clinical studies are needed to gain greater molecular insight into PLD.     

Detection of a non-structural protein of M r 11 000 encoded by the virion DNA of maize streak virus

A polypeptide of approximately 11 000 daltons (11 kDa protein) encoded by an open reading frame (10.9 ORF) from the virion sense of maize streak virus (MSV) DNA has been detected among the products of in vitro translation reactions programmed with RNA from infected maize plants and also in total protein extracts from infected leaves. The 11 kDa protein has not been detected in virions and is therefore proposed to have a nonstructural role.Viral DNA with an additional in-frame translation stop codon in the 10.9 ORF was not infectious when transmitted to maize plants via Agrobacterium tumefaciens agroinfection, suggesting that the 10.9 ORF may be essential for virus function. Computer comparison data show that equivalent ORFs in wheat dwarf virus (WDV) and digitaria streak virus (DSV) have some sequences in common with the 10.9 ORF of MSV. Further-more, the absence of similar sequences in geminiviruses which infect dicotyledonous plants suggests that the 11 kDa protein and its putative homologs in WDV and DSV have a function necessary only for those geminiviruses which infect the Gramineae.The significance of the 11 kDa protein in relation to expression of the virion sense DNA of MSV is discussed.