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Markus Hoffmann Nadine Krüger Pawel Zmora Florian Wrensch Georg Herrler Stefan P?hlmann 《PloS one》2016,11(3)
New World bats have recently been discovered to harbor influenza A virus (FLUAV)-related viruses, termed bat-associated influenza A-like viruses (batFLUAV). The internal proteins of batFLUAV are functional in mammalian cells. In contrast, no biological functionality could be demonstrated for the surface proteins, hemagglutinin (HA)-like (HAL) and neuraminidase (NA)-like (NAL), and these proteins need to be replaced by their human counterparts to allow spread of batFLUAV in human cells. Here, we employed rhabdoviral vectors to study the role of HAL and NAL in viral entry. Vectors pseudotyped with batFLUAV-HAL and -NAL were able to enter bat cells but not cells from other mammalian species. Host cell entry was mediated by HAL and was dependent on prior proteolytic activation of HAL and endosomal low pH. In contrast, sialic acids were dispensable for HAL-driven entry. Finally, the type II transmembrane serine protease TMPRSS2 was able to activate HAL for cell entry indicating that batFLUAV can utilize human proteases for HAL activation. Collectively, these results identify viral and cellular factors governing host cell entry driven by batFLUAV surface proteins. They suggest that the absence of a functional receptor precludes entry of batFLUAV into human cells while other prerequisites for entry, HAL activation and protonation, are met in target cells of human origin. 相似文献
3.
K Krzemiński W Niewiadomski K Nazar 《European journal of applied physiology and occupational physiology》1989,59(5):377-384
Eighteen male volunteers (aged 20-23 years), not involved in any sporting activities, were submitted to 13 weeks of training consisting of 30 min exercise [at 50%-75% maximal oxygen intake (VO2max)] on a cycle ergometer, performed 3 times a week. Every 4 weeks cardiac function was evaluated by measuring the systolic time intervals at rest and during submaximal cycle exercise. Stroke volume (SV), heart rate (HR) and blood pressure (BP) responses to submaximal exercise, VO2max and anaerobic threshold (AT) were also determined. Significant increases in VO2max, increases in AT and SV at the submaximal exercise intensities, as well as decreases in HR and BP were found after 4 weeks of training. Resting systolic time intervals were not affected by training, but during the submaximal cycle exercise the values of the pre-ejection period (PEP) and isovolumic contraction time (ICT) corresponding to HR of 100 beats.min-1 were significantly lowered after 13 weeks of training, whereas PEP, ICT and total electromechanical systole corresponding to HR of 130 beats.min-1 were significantly shortened by the 4th week. The ratios of PEP:LVET (left ventricular ejection time) and ICT:LVET during submaximal exercise were significantly lowered by training starting from the 8th week. These changes might be interpreted as evidence of the training-induced enhancement of the "contractility reserve", i.e. the ability to increase heart muscle contractility with increasing exercise intensity. 相似文献
4.
The time dependence of the human
1-antitrypsin polymerization process was studied by means of the intrinsic fluorescence stopped-flow technique as well as the fluorescence-quenching-resolved spectra (FQRS) method and native PAGE. The polymerization was induced by mild denaturing conditions (1 M GuHCl) and temperature. The data show that the dimer formation reaction under mild conditions was followed by an increase of fluorescence intensity. This phenomenon is highly temperature sensitive. The structure of
1-antitrypsin dimer resembles the conformation of antithrombin III dimer. In the presence of the denaturant the polymerization process is mainly limited to the dimer state. The
1-antitrypsin activity measurements confirm monomer-to-dimer transition under these conditions. These results are in contrast to the polymerization process induced by temperature, where the dimer state is an intermediate step leading to long-chain polymers. On the basis of stopped-flow and electrophoretic data it is suggested that both C-sheet as well as A-sheet mechanisms contribute to the polymerization process under mild conditions.Abbreviations GuHCL
guanidinium hydrochloride
- RSL
reactive site loop
- PAI-1
plasminogen activator inhibitor type 1
- AT III
antithrombin III
- FQRS
fluorescence quenching resolved spectra 相似文献
5.
Pawel Palkiewicz† Henk Zwiers† Fritz L. Lorscheider† 《Journal of neurochemistry》1994,62(5):2049-2052
Abstract: ADP-ribosylation is an essential process in the metabolism of brain neuronal proteins, including the regulation of assembly and disassembly of biological polymers. Here, we examine the effect of HgCl2 exposure on the ADP-ribosylation of tubulin and actin, both cytoskeletal proteins also found in neurons, and B-50/43-kDa growth-associated protein (B-50/GAP-43), a neuronal tissue-specific phosphoprotein. In rats we demonstrate, with both in vitro and in vivo experiments, that HgCl2 markedly inhibits the ADP-ribosylation of tubulin and actin. This is direct quantitative evidence that HgCl2, a toxic xenobiotic, alters specific neurochemical reactions involved in maintaining brain neuron structure. 相似文献
6.
Soldati Adrian Muhumuza Geresomu Dezecache Guillaume Fedurek Pawel Taylor Derry Call Josep Zuberbühler Klaus 《International journal of primatology》2023,44(1):116-139
International Journal of Primatology - Observations of early vocal behaviours in non-human primates (hereafter primates) are important for direct comparisons between human and primate vocal... 相似文献
7.
Yan, Sheng, Pawel Sliwinski, and Peter T. Macklem.Association of chest wall motion and tidal volume responses during CO2 rebreathing.J. Appl. Physiol. 81(4):1528-1534, 1996.The purpose of this study is to investigate theeffect of chest wall configuration at end expiration on tidal volume(VT) response duringCO2 rebreathing. In a group of 11 healthy male subjects, the changes in end-expiratory andend-inspiratory volume of the rib cage (Vrc,E andVrc,I, respectively) and abdomen (Vab,E and Vab,I, respectively) measured by linearizedmagnetometers were expressed as a function of end-tidalPCO2(PETCO2). The changes inend-expiratory and end-inspiratory volumes of the chest wall(Vcw,E and Vcw,I,respectively) were calculated as the sum of the respectiverib cage and abdominal volumes. The magnetometer coils were placed atthe level of the nipples and 1-2 cm above the umbilicus andcalibrated during quiet breathing against theVT measured from apneumotachograph. TheVrc,E/PETCO2 slope was quite variable among subjects. It was significantly positive (P < 0.05) in fivesubjects, significantly negative in four subjects(P < 0.05), and not different fromzero in the remaining two subjects. TheVab,E/PETCO2slope was significantly negative in all subjects(P < 0.05) with a much smallerintersubject variation, probably suggesting a relatively more uniformrecruitment of abdominal expiratory muscles and a variable recruitmentof rib cage muscles during CO2rebreathing in different subjects. As a group, the meanVrc,E/PETCO2,Vab,E/PETCO2, andVcw,E/PETCO2slopes were 0.010 ± 0.034, 0.030 ± 0.007, and0.020 ± 0.032 l / Torr, respectively;only theVab,E/PETCO2 slope was significantly different from zero. More interestingly, theindividualVT/PETCO2slope was negatively associated with theVrc,E/PETCO2(r = 0.68,P = 0.021) and Vcw,E/PETCO2slopes (r = 0.63,P = 0.037) but was not associated withtheVab,E/PETCO2slope (r = 0.40, P = 0.223). There was no correlation oftheVrc,E/PETCO2 andVcw,E/PETCO2slopes with age, body size, forced expiratory volume in 1 s, orexpiratory time. The groupVab,I/PETCO2 slope (0.004 ± 0.014 l / Torr) was not significantlydifferent from zero despite theVT nearly being tripled at theend of CO2 rebreathing. Inconclusion, the individual VTresponse to CO2, althoughindependent of Vab,E, is a function ofVrc,E to the extent that as theVrc,E/PETCO2slope increases (more positive) among subjects, theVT response toCO2 decreases. These results maybe explained on the basis of the respiratory muscle actions andinteractions on the rib cage. 相似文献
8.
Incubation of human T cells for 18 hr with prostaglandin E2 (PGE2 3 × 10?6M) causes a slight but significant increase in the percentage of Tγ cells and a reduction in Tμ cells. When PGE was added to “non-Tγ” cells, the increase in the percentage of Tγ cells was more marked (from 1.5% Tγ without PGE to 11% Tγ with PGE2, P < 0.001). Supernates from cultures of human monocytes also caused an increase in Tγ cells (10% Tγ without supernate to 18% with supernate, P < 0.01), and this increase was blocked if the monocytes were cultured with indomethacin, a prostaglandin synthetase inhibitor (9% Tγ cells). Thus, monocytes may regulate Fcγ receptors on T cells via PGE2 production. 相似文献
9.
Zhu Y Carragher B Glaeser RM Fellmann D Bajaj C Bern M Mouche F de Haas F Hall RJ Kriegman DJ Ludtke SJ Mallick SP Penczek PA Roseman AM Sigworth FJ Volkmann N Potter CS 《Journal of structural biology》2004,145(1-2):3-14
Manual selection of single particles in images acquired using cryo-electron microscopy (cryoEM) will become a significant bottleneck when datasets of a hundred thousand or even a million particles are required for structure determination at near atomic resolution. Algorithm development of fully automated particle selection is thus an important research objective in the cryoEM field. A number of research groups are making promising new advances in this area. Evaluation of algorithms using a standard set of cryoEM images is an essential aspect of this algorithm development. With this goal in mind, a particle selection "bakeoff" was included in the program of the Multidisciplinary Workshop on Automatic Particle Selection for cryoEM. Twelve groups participated by submitting the results of testing their own algorithms on a common dataset. The dataset consisted of 82 defocus pairs of high-magnification micrographs, containing keyhole limpet hemocyanin particles, acquired using cryoEM. The results of the bakeoff are presented in this paper along with a summary of the discussion from the workshop. It was agreed that establishing benchmark particles and using bakeoffs to evaluate algorithms are useful in promoting algorithm development for fully automated particle selection, and that the infrastructure set up to support the bakeoff should be maintained and extended to include larger and more varied datasets, and more criteria for future evaluations. 相似文献
10.
Formamidopyrimidine-DNA glycosylase (Fpg; MutM) is a DNA repair enzyme widely distributed in bacteria. Fpg recognizes and excises oxidatively modified purines, 4,6-diamino-5-formamidopyrimidine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine and 8-oxoguanine (8-oxoG), with similar excision kinetics. It exhibits some lesser activity toward 8-oxoadenine. Fpg enzymes are also present in some plant and fungal species. The eukaryotic Fpg homologs exhibit little or no activity on DNA containing 8-oxoG, but they recognize and process its oxidation products, guanidinohydantoin (Gh) and spiroiminohydantoin (Sp). To date, several structures of bacterial Fpg enzymes unliganded or in complex with DNA containing a damaged base have been published but there is no structure of a eukaryotic Fpg. Here we describe the first crystal structure of a plant Fpg, Arabidopsis thaliana (AthFpg), unliganded and bound to DNA containing an abasic site analog, tetrahydrofuran (THF). Although AthFpg shares a common architecture with other Fpg glycosylases, it harbors a zincless finger, previously described in a subset of Nei enzymes, such as human NEIL1 and Mimivirus Nei1. Importantly the "αF-β9/10 loop" capping 8-oxoG in the active site of bacterial Fpg is very short in AthFpg. Deletion of a segment encompassing residues 213-229 in Escherichia coli Fpg (EcoFpg) and corresponding to the "αF-β9/10 loop" does not affect the recognition and removal of oxidatively damaged DNA base lesions, with the exception of 8-oxoG. Although the exact role of the loop remains to be further explored, it is now clear that this protein segment is specific to the processing of 8-oxoG. 相似文献