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871.
872.
Allison M. Land Nadine M. Shaban Leah Evans Judd F. Hultquist John S. Albin Reuben S. Harris 《Journal of virology》2014,88(21):12923-12927
HIV-1 Vif counteracts restrictive APOBEC3 proteins by targeting them for proteasomal degradation. To determine the regions mediating sensitivity to Vif, we compared human APOBEC3F, which is HIV-1 Vif sensitive, with rhesus APOBEC3F, which is HIV-1 Vif resistant. Rhesus-human APOBEC3F chimeras and amino acid substitution mutants were tested for sensitivity to HIV-1 Vif. This approach identified the α3 and α4 helices of human APOBEC3F as important determinants of the interaction with HIV-1 Vif. 相似文献
873.
D. J. Harris S. Carranza E. N. Arnold C. Pinho N. Ferrand 《Journal of Biogeography》2002,29(9):1257-1262
Abstract Aim To examine the effect of a known geological barrier on genetic variation within a wall lizard species complex. Location The Iberian Peninsula and North Africa. Methods Sequencing of partial 12S rRNA and cytochrome b mtDNA. Results The current distribution of genetic variability is not related to the opening of the Strait of Gibraltar. Conclusions Podarcis hispanica in North Africa is probably a species complex. The Strait of Gibraltar should not be used as a known barrier to gene flow in other land based organisms without careful sampling to test for multiple crossings since its formation. 相似文献
874.
Vitrified synthetic phosphatidycholine liposome suspensions were studied by cryo-electron microscopy. The bilayer structure is resolved on vitrified liposome images. The packing of the aliphatic chains of the lipid within vitrified liposomes can be determined by the analysis of electron diffraction patterns. Images and electron diffraction patterns show that the structure of vitrified liposomes is related to the structure that liposomes have before vitrification. In fact, vitrified liposomes have a different structure, depending whether they are maintained before cooling at a temperature higher or lower than that corresponding to the ‘melting’ of the hydrocarbon chain of the lipids. Below the melting temperature, liposomes are formed by small domains. 相似文献
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Rabea Schlueter Anja Röder Nadine Czekalski Daniel Gliesche Annett Mikolasch Frieder Schauer 《Applied microbiology and biotechnology》2014,98(1):373-384
The compound p-tert-amylphenol (p-(1,1-dimethylpropyl)phenol) is a widely used disinfectant belonging to the group of short branched-chain alkylphenols. It is produced in or imported into the USA with more than one million pounds per year and can be found in the environment in surface water, sediments, and soil. We have investigated for the first time the biotransformation of this disinfectant and the accumulation of metabolites by five bacterial strains, three yeast strains, and three filamentous fungi, selected because of their ability to transform either aromatic or branched-chain compounds. Of the 11 microorganisms tested, one yeast strain and three bacteria could not transform the disinfectant despite of a very low concentration applied (0.005 %). None of the other seven organisms was able to degrade the short branched alkyl chain of p-tert-amylphenol. However, two yeast strains, two filamentous fungi, and two bacterial strains attacked the aromatic ring system of the disinfectant via the hydroxylated intermediate 4-(1,1-dimethyl-propyl)-benzene-1,2-diol resulting in two hitherto unknown ring fission products with pyran and furan structures, 4-(1,1-dimethyl-propyl)-6-oxo-6-H-pyran-2-carboxylic acid and 2-[3-(1,1-dimethyl-propyl)-5-oxo-2H-furan-2-yl]acetic acid. While the disinfectant was toxic to the organisms applied, one of the ring cleavage products was not. Thus, a detoxification of the disinfectant was achieved by ring cleavage. Furthermore, one filamentous fungus formed sugar conjugates with p-tert-amylphenol as another mechanism of detoxification of toxic environmental pollutants. With this work, we can also contribute to the allocation of unknown chemical compounds within environmental samples to their parent compounds. 相似文献
878.
Fabien Sohet Christina Lin Roeben N. Munji Seo Yeon Lee Nadine Ruderisch Allison Soung Thomas D. Arnold Nikita Derugin Zinaida S. Vexler Frances T. Yen Richard Daneman 《The Journal of cell biology》2015,208(6):703-711
The blood–brain barrier (BBB) is a term used to describe the unique properties of central nervous system (CNS) blood vessels. One important BBB property is the formation of a paracellular barrier made by tight junctions (TJs) between CNS endothelial cells (ECs). Here, we show that Lipolysis-stimulated lipoprotein receptor (LSR), a component of paracellular junctions at points in which three cell membranes meet, is greatly enriched in CNS ECs compared with ECs in other nonneural tissues. We demonstrate that LSR is specifically expressed at tricellular junctions and that its expression correlates with the onset of BBB formation during embryogenesis. We further demonstrate that the BBB does not seal during embryogenesis in Lsr knockout mice with a leakage to small molecules. Finally, in mouse models in which BBB was disrupted, including an experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis and a middle cerebral artery occlusion (MCAO) model of stroke, LSR was down-regulated, linking loss of LSR and pathological BBB leakage. 相似文献
879.
Robert Huber Thomas G Palmen Nadine Ryk Anne-Kathrin Hillmer Karina Luft Frank Kensy Jochen Büchs 《BMC biotechnology》2010,10(1):22
Background
High-throughput cultivations in microtiter plates are the method of choice to express proteins from recombinant clone libraries. Such processes typically include several steps, whereby some of them are linked by replication steps: transformation, plating, colony picking, preculture, main culture and induction. In this study, the effects of conventional replication methods and replication tools (8-channel pipette, 96-pin replicators: steel replicator with fixed or spring-loaded pins, plastic replicator with fixed pins) on growth kinetics of Escherichia coli SCS1 pQE-30 pSE111 were observed. Growth was monitored with the BioLector, an on-line monitoring technique for microtiter plates. Furthermore, the influence of these effects on product formation of Escherichia coli pRhotHi-2-EcFbFP was investigated. Finally, a high-throughput cultivation process was simulated with Corynebacterium glutamicum pEKEx2-phoD-GFP, beginning at the colony picking step. 相似文献880.