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61.
Daniela Wojta-Stremayr Alina Neunkirchner Bharani Srinivasan Doris Trapin Klaus G. Schmetterer Winfried F. Pickl 《PloS one》2015,10(5)
A variety of adjuvants fostering humoral immunity are known as of today. However, there is a lack of adjuvants or adjuvant strategies, which directly target T cellular effector functions and memory. We here determined whether systemically toxic cytokines such as IL-2 can be restricted to the site of antigen presentation and used as ‘natural adjuvants’. Therefore, we devised antigen-presenting virus-like nanoparticles (VNP) co-expressing IL-2 attached to different membrane-anchors and assessed their potency to modulate CD8+ T cell responses in vitro and in vivo. Efficient targeting of IL-2 to lipid rafts and ultimately VNP was achieved by fusing IL-2 at its C-terminus to a minimal glycosylphosphatidylinositol (GPI)-anchor acceptor sequence. To identify optimal membrane-anchor dimensions we inserted one (1Ig), two (2Ig) or four (4Ig) immunoglobulin(Ig)-like domains of CD16b between IL-2 and the minimal GPI-anchor acceptor sequence of CD16b (GPI). We found that the 2IgGPI version was superior to all other evaluated IL-2 variants (IL-2v) in terms of its i) degree of targeting to lipid rafts and to the VNP surface, ii) biological activity, iii) co-stimulation of cognate T cells in the absence of bystander activation and iv) potency to induce differentiation and acquisition of CD8+ T cell effector functions in vitro and in vivo. In contrast, the GPI version rather favored memory precursor cell formation. These results exemplify novel beneficial features of membrane-bound IL-2, which in addition to its mere T cell stimulatory capacity include the induction of differential effector and memory functions in CD8+ T lymphocytes. 相似文献
62.
Liubov Petrakova Bettina K. Doering Sabine Vits Harald Engler Winfried Rief Manfred Schedlowski Jan-Sebastian Grigoleit 《PloS one》2015,10(8)
Salivary alpha-amylase activity (sAA) and plasma noradrenaline (NA) concentrations are often considered to be surrogate markers of sympathetic activation in response to stress. However, despite accumulating evidence for a close association between sAA and noradrenaline and other indicators of sympathetic activity, reliability and generality of this relation remains unclear. We employed the Trier Social Stress Test (TSST) in order to directly compare the responses in sAA and NA to psychological stress in healthy volunteers (n = 23). The TSST significantly increased sAA and NA plasma levels with no significant differences in females and males. However, when subjects were divided according to their NA responses into low versus high responders, both groups did not significantly differ in their sAA before, during or after stress exposure. These data suggest that in response to acute psychological stress both plasma NA levels and sAA reflect sympathetic activity, however seemed to increase independently from each other. 相似文献
63.
Krueger WH Swanson LC Tanasijevic B Rasmussen TP 《The International journal of developmental biology》2010,54(11-12):1545-1564
Pluripotent cells of the blastocyst inner cell mass (ICM) and their in vitro derivatives, embryonic stem (ES) cells, contain genomes in an epigenetic state that are poised for subsequent differentiation. Their chromatin is hyperdynamic in nature and relatively uncondensed. In addition, a large number of genes are expressed at low levels in both ICM and ES cells. Also, the chromatin of naturally pluripotent cells contains specialized histone modification patterns such as bivalent domains, which mark genes destined for later developmentally-regulated expression states. Female pluripotent cells contain X chromosomes that have yet to undergo the process of X chromosome inactivation. Collectively, these features of very early embyronic chromatin are required for the successful specification and production of differentiated cell lineages. Artificial reprogramming methods such as somatic nuclear transfer (SCNT), ES cell fusion-mediated reprogramming (FMR), and induced pluripotency (iPS) yield pluripotent cells that recapitulate many features of naturally pluripotent cells, including many of their epigenetic features. However, the route to pluripotent epigenomic states in artificial pluripotent cells differs drastically from that of their natural counterparts. Here, we compare and contrast the differing routes to pluripotency under natural and artificial conditions. In addition, we discuss the intrinsically metastable nature of the pluripotent epigenome and consider epigenetic aspects of reprogramming that may lead to incomplete or inaccurate reprogrammed states. Artificial methods of reprogramming hold immense promise for the development of autologous cell graft sources and for the development of cell culture models for human genetic disorders. However, the utility of artificially reprogrammed cells is highly dependent on the fidelity of the reprogramming process and it is therefore critically important to assess the epigenetic similarities between embryonic and induced pluripotent stem cells. 相似文献
64.
Ngo Thi Hai Yen Xenia Bogdanović Gottfried J. Palm Olaf Kühl Winfried Hinrichs 《Journal of biological inorganic chemistry》2010,15(2):195-201
Crystal structures of polypeptide deformylase (PDF) of Escherichia coli with nickel(II) replacing the native iron(II) have been solved with chloride and formate as metal ligands. The chloro complex
is a model for the correct protonation state of the hydrolytic hydroxo ligand and the protonated status of the Glu133 side
chain as part of the hydrolytic mechanism. The ambiguity that recently some PDFs have been identified with Zn2+ ion as the active-site centre whereas others are only active with Fe2+ (or Co2+, Ni2+) is discussed with respect to Lewis acid criteria of the metal ion and substrate activation by the CD loop. 相似文献
65.
Siegbert Rieg Benjamin Meier Eva Fähnrich Anja Huth Dirk Wagner Winfried V Kern Hubert Kalbacher 《BMC microbiology》2010,10(1):61
Background
Members of the genus Nocardia are ubiquitous environmental saprophytes capable to cause human pulmonary, disseminated and cutaneous nocardiosis or bovine mastitis. Innate immunity appears to play an important role in early defense against Nocardia species. To elucidate the contribution of antimicrobial peptides (AMPs) in innate defense against Nocardia, the activity of human α-defensins human neutrophil peptides (HNPs) 1-3, human β-defensin (hBD)-3 and cathelicidin LL-37 as well as bovine β-defensins lingual and tracheal antimicrobial peptides (LAP, TAP) and bovine neutrophil-derived indolicidin against four important Nocardia species was investigated. 相似文献66.
Winfried Hartmeier 《Trends in biotechnology》1985,3(6):149-153
Until recently it was only practical to use immobilized systems containing single enzymes or whole cells. More complex systems providing cofactor regeneration outside living cells have now been developed; coimmobilization of enzymes, cells and organelles from different organisms promises to improve further the industrial feasibility of immobilized biocatalysts. 相似文献
67.
Behavioral and electrophysiological experiments have shown that the elongated paddlefish rostrum, with its extensive population of ampullae of Lorenzini, constitutes a passive electrosensory antenna of great sensitivity and spatial resolution. As demonstrated in juvenile paddlefish, the passive electrosense serves a novel function in feeding serving as the primary, if not exclusive sensory modality for the detection and capture of zooplanktonic prey. Ampullary receptors are sensitive to the weak electrical fields of plankton from distances up to 9 cm, and juvenile paddlefish capture plankton individually with great swimming dexterity in the absence of vision or other stimulus signals. Paddlefish also detect and avoid metal obstacles, the electrical signatures of which are a potential hindrance to their feeding and reproductive migrations. The ampullary receptors, their peripheral innervation and central targets in the dorsal octavolateral nucleus, are described. We also describe the ascending and descending neuronal circuitry of the electrosensory system in the brain based on tracer studies using dextran amines. 相似文献
68.
Schäfer C Parlesak A Eckoldt J Bode C Bode JC März W Winkler K 《Journal of lipid research》2007,48(7):1550-1558
The reduction of cardiovascular mortality associated with moderate alcohol consumption is chiefly thought to be mediated by an increase of high density lipoprotein cholesterol (HDL-CH). This study highlights additional qualitative changes of HDL that might augment this antiatherogenic effect. In 279 healthy men, alcohol and nutrient consumption were evaluated. Groups 1 (n=62), 2 (n=172), and 3 (n=45) comprised subjects with alcohol consumption of 0-5.0, 5.1-30.0, and 30.1-75 g/day, respectively. Lipid analysis was performed in nonfractionated and fractionated plasma, including subfractions HDL(2a), HDL(2b), and HDL(3). No difference in LDL-cholesterol was observed. Compared with group 1, groups 2 and 3 exhibited significant increases of HDL-CH (group 1, 44 +/- 10 mg/dl; group 2, 51 +/- 11 mg/dl; group 3, 55 +/- 11 mg/dl; mean +/- SD, P<0.0005), accompanied by enhanced lipidation of HDL (increase of the HDL(2)-CH/HDL(3)-CH ratio). Moreover, phospholipid enrichment of HDL occurred in alcohol consumers, whereas the ratios between other HDL components remained constant. Multivariate analysis revealed alcohol to have the foremost statistical influence on changes of the HDL fraction, followed by body mass index and physical activity level. The increased lipidation of HDL found in alcohol consumers might augment the antiatherogenic effect of HDL-CH increase. In addition, the phospholipid enrichment of HDL might reduce the inflammatory response of atherogenesis. 相似文献
69.
Albertini AA Clapier CR Wernimont AK Schoehn G Weissenhorn W Ruigrok RW 《Journal of structural biology》2007,158(1):129-133
In order to study the packaging of rabies virus RNA inside the viral nucleocapsid, rabies nucleoprotein was expressed in insect cells. In the cells, it binds to cellular RNA to form long, helical or short circular complexes, depending on the length of the bound RNA. The circular complexes contained from 9 up to 13 N-protomers per ring. Separation of the rings into defined size classes was impossible through regular column chromatographies or gradient centrifugation. The size classes could be separated by native polyacrylamide gel electrophoresis. A large-scale separation was achieved with a 4% native gel using a preparative electrophoresis apparatus. Crystallization trials were set up with N-RNA rings from three size classes and crystals were obtained in all cases. The best diffracting crystals, diffracting up to 6A, contained rings with 11 N-protomers plus an RNA molecule of 99 nucleotides. The diffraction limit was improved to 3.5A by air dehydration prior to flash freezing. 相似文献
70.
Marjolein Glas H. Bart van den Berg van Saparoea Stephen H. McLaughlin Winfried Roseboom Fan Liu Gregory M. Koningstein Alexander Fish Tanneke den Blaauwen Albert J. R. Heck Luitzen de Jong Wilbert Bitter Iwan J. P. de Esch Joen Luirink 《The Journal of biological chemistry》2015,290(35):21498-21509
Cell division in Escherichia coli involves a set of essential proteins that assembles at midcell to form the so-called divisome. The divisome regulates the invagination of the inner membrane, cell wall synthesis, and inward growth of the outer membrane. One of the divisome proteins, FtsQ, plays a central but enigmatic role in cell division. This protein associates with FtsB and FtsL, which, like FtsQ, are bitopic inner membrane proteins with a large periplasmic domain (denoted FtsQp, FtsBp, and FtsLp) that is indispensable for the function of each protein. Considering the vital nature and accessible location of the FtsQBL complex, it is an attractive target for protein-protein interaction inhibitors intended to block bacterial cell division. In this study, we expressed FtsQp, FtsBp, and FtsLp individually and in combination. Upon co-expression, FtsQp was co-purified with FtsBp and FtsLp from E. coli extracts as a stable trimeric complex. FtsBp was also shown to interact with FtsQp in the absence of FtsLp albeit with lower affinity. Interactions were mapped at the C terminus of the respective domains by site-specific cross-linking. The binding affinity and 1:1:1 stoichiometry of the FtsQpBpLp complex and the FtsQpBp subcomplex were determined in complementary surface plasmon resonance, analytical ultracentrifugation, and native mass spectrometry experiments. 相似文献