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Efficient retroviral infection of mammalian cells is blocked by inhibition of poly(ADP-ribose) polymerase activity. 总被引:1,自引:4,他引:1
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Vladimir V Egorov Dmitry V Lebedev Aram A Shaldzhyan Alexey K Sirotkin Andrey N Gorshkov Olga A Mirgorodskaya 《朊病毒》2014,8(5):369-373
The fibrillogenesis of a peptide corresponding to residues 35–51 of human α-lactalbumin (1GYDTQAIVENNESTEYG17) can be dramatically enhanced by the addition of a tetrapeptide TDYG homologous to its C-terminus (TEYG). Generation of spontaneous hydrolytic products similar to this peptide was demonstrated by mass-spectrometry analysis of GYDTQAIVENNESTEYG peptide solution components during fibrillogenesis. Possible mechanisms and roles of short peptides in protein metabolism are discussed. 相似文献
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Myxococous xanthus cells can glide both as individual cells, dependent on A dventurous motility (A motility), and as groups of cells, dependent upon S ocial motility (S motility), Tn5-lac mutagenesis was used to generate 16 new A- and nine new S- mutations. In contrast with previous results, we find that subsets of A- mutants are defective in fruiting body morphogenesis and/or myxospore differentiation. All S- mutants are defective in fruiting body morphogenesis, consistent with previous results. Whereas some S- mutants produce a wild-type complement of spores, others are defective in the differentiation of myxospores. Therefore, a subset of the A genes and all of the S genes are critical for fruiting body morphogenesis. Subsets of both A and S genes are essential for sporulation. Three S::Tn5–lac insertions result in surprising phenotypes. Colonies of two S- mutants glide on ‘swim’ (0.35% agar) plates to form fractal patterns. These S- mutants are the first examples of a bacterium in which mutations result in fractal patterns of colonial spreading. An otherwise wild-type strain with one S- insertion resembles the frz- sglA1- mutants upon development, suggesting that this S- gene defines a new chemotaxis component in M. xanthus. 相似文献
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Farzaneh Harraf Anil K Sharma Martin M Brown Kennedy R Lees Richard I Vass Lalit Kalra 《BMJ (Clinical research ed.)》2002,325(7354):17
ObjectiveTo investigate delays in the presentation to hospital and evaluation of patients with suspected stroke.DesignMulticentre prospective observational study.Setting22 hospitals in the United Kingdom and Dublin.Participants739 patients with suspected stroke presenting to hospital.ResultsThe median age of patients was 75 years, and 400 were women. The median delay between onset of symptoms and arrival at hospital was 6 hours (interquartile range 1 hour 48 minutes to 19 hours 12 minutes). 37% of patients arrived within 3 hours, 50% within 6 hours. The median delay for patients using the emergency service was 2 hours 3 minutes (47 minutes to 7 hours 12 minutes) compared with 7 hours 12 minutes (2 hours 5 minutes to 20 hours 37 minutes) for referrals from general practitioners (P<0.0001). Use of emergency services reduced delays to hospital (odds ratio 0.45, 95% confidence interval 0.23 to 0.61). The median time to evaluation by a senior doctor was 1 hour 9 minutes (interquartile range 33 minutes to 1 hour 50 minutes) but was undertaken in only 477 (65%) patients within 3 hours of arrival. This was not influenced by age, sex, time of presentation, mode of referral, hospital type, or the presence of a stroke unit. Computed tomography was requested within 3 hours of arrival in 166 (22%) patients but undertaken in only 60 (8%).ConclusionDelays in patients arriving at hospital with suspected stroke can be reduced by the increased use of emergency services. Over a third of patients arrive at hospital within three hours of stroke; their management can be improved by expediting medical evaluation and performing computed tomography early.