Investigations on the Tobacco necrosis virus D p60 replicase protein

Copyright: © 2013 Fang, Coutts. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedTobacco necrosis virus D (TNV-D), in the genus Betanecrovirus (family Tombusviridae), possesses a single-stranded, positive-sense RNA genome containing six open reading frames (ORFs). Two 5'-proximal ORFs (1 and 2) encode overlapping polypeptides of 22 and 82 kDa (p22 and p82, respectively) which are both required for replication. The p22 auxiliary protein contains no replication motifs but the C-terminal region, downstream of a leaky stop codon, encodes a 60 kDa polypeptide (p60) which contains conserved RNA-dependent RNA polymerase (RdRP) motifs. Here we have expressed and purified recombinant p60 and show that in vitro it binds and efficiently synthesises both TNV-D RNA and Satellite tobacco necrosis virus C RNA. Alanine scanning mutagenesis of conserved amino acids in characteristic motifs in p60 revealed that some mutations significantly reduced RNA synthesis but mutating the second asparagine residue in the conserved GDD box was lethal. The effects of mutating identical amino acids in p60 on virus replication in vivo were examined in Nicotiana benthamiana plants following infection with RNA transcribed from wild type (wt) and mutant constructs. In inoculated leaves the behaviour of the mutants paralleled the in vitro data but systemic infection was precluded in all but one mutant which had reverted to wt. This study is the first to demonstrate the nucleic acid-binding and synthetic capabilities of a betanecrovirus polymerasePeer reviewe

Pharmacokinetics of Stavudine and Didanosine Coadministered with Nelfinavir in Human Immunodeficiency Virus-Exposed Neonates

We evaluated the pharmacokinetics of stavudine (d4T) and didanosine (ddI) in neonates. Eight neonates born to human immunodeficiency virus-infected mothers were enrolled to receive 1 mg of d4T per kg of body weight twice daily and 100 mg of ddI per m(2) once daily in combination with nelfinavir for 4 weeks after birth. Pharmacokinetic evaluations were performed at 14 and 28 days of age. For d4T, on days 14 and 28, the median areas under the concentration-time curves from 0 to 12 h (AUC(0–12)s) were 1,866 and 1,603, ng · h/ml, respectively, and the median peak concentrations (C(max)s) were 463 and 507 ng/ml, respectively. For ddI, on days 14 and 28, the median AUC(0–10)s were 1,573 and 1,562 h · ng/ml, respectively, and the median C(max)s were 627 and 687 ng/ml, respectively. Systemic levels of exposure to d4T were comparable to those seen in children, suggesting that the pediatric dose of 1 mg/kg twice daily is appropriate for neonates at 2 to 4 weeks of age. Levels of exposure to ddI were modestly higher than those seen in children. Whether this observation warrants a reduction of the ddI dose in neonates is unclear

За кадры. 1970. № 27 (1462)

Победители соревнования. Впереди идут ФТФ, ЭМФ, ХТФ / А. Гагарин [и др.]Человек высокого долга / А. ПортягинНужна перестройка / М. Ф. ПолетикаПамятник ко дню Победы / Р. Горская"Вестник высшей школы". Краткий обзорСтуденческая юбилейная / О. СтепановаБригантина поднимат паруса / Н. ФедороваДождь и снег - не помеха / О. ВолодинаЕсли готовите снимок на выставку... / Г. ХлопковНе выходят на благоустройство / Б. ДерчанскийКомнату - на все пять летВесенняя лирика. Тяжелый снег пропитан соком... / С. ЯковлевВесенняя лирика. Граница - это не только нейтраль... / В. БояриновВесенняя лирика. В тебе мне нравится твоя твердость... / А. ШипелеваВесенняя лирика. Короткий разговор / О. ФедюшинаНаедине с природой / А. СобанинДебоширы наказаны / И. И. КаляцкийНовые книги о В. И. ЛенинеНа первом месте - комсомольцы АВТФ / Г. Гогу