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81.
Urban S Textoris-Taube K Reimann B Janek K Dannenberg T Ebstein F Seifert C Zhao F Kessler JH Halenius A Henklein P Paschke J Cadel S Bernhard H Ossendorp F Foulon T Schadendorf D Paschen A Seifert U 《Journal of immunology (Baltimore, Md. : 1950)》2012,189(2):529-538
Control of human CMV (HCMV) infection depends on the cytotoxic activity of CD8(+) CTLs. The HCMV phosphoprotein (pp)65 is a major CTL target Ag and pp65(495-503) is an immunodominant CTL epitope in infected HLA-A*0201 individuals. As immunodominance is strongly determined by the surface abundance of the specific epitope, we asked for the components of the cellular Ag processing machinery determining the efficacy of pp65(495-503) generation, in particular, for the proteasome, cytosolic peptidases, and endoplasmic reticulum (ER)-resident peptidases. In vitro Ag processing experiments revealed that standard proteasomes and immunoproteasomes generate the minimal 9-mer peptide epitope as well as N-terminal elongated epitope precursors of different lengths. These peptides are largely degraded by the cytosolic peptidases leucine aminopeptidase and tripeptidyl peptidase II, as evidenced by increased pp65(495-503) epitope presentation after leucine aminopeptidase and tripeptidyl peptidase II knockdown. Additionally, with prolyl oligopeptidase and aminopeptidase B we identified two new Ag processing machinery components, which by destroying the pp65(495-503) epitope limit the availability of the specific peptide pool. In contrast to cytosolic peptidases, silencing of ER aminopeptidases 1 and 2 strongly impaired pp65(495-503)-specific T cell activation, indicating the importance of ER aminopeptidases in pp65(495-503) generation. Thus, cytosolic peptidases primarily interfere with the generation of the pp65(495-503) epitope, whereas ER-resident aminopeptidases enhance such generation. As a consequence, our experiments reveal that the combination of cytosolic and ER-resident peptidase activities strongly shape the pool of specific antigenic peptides and thus modulate MHC class I epitope presentation efficiency. 相似文献
82.
Minne Casteels Veerle Foulon Guy P Mannaerts Paul P Van Veldhoven 《European journal of biochemistry》2003,270(8):1619-1627
3-Methyl-branched fatty acids, as phytanic acid, undergo peroxisomal alpha-oxidation in which they are shortened by 1 carbon atom. This process includes four steps: activation, 2-hydroxylation, thiamine pyrophosphate dependent cleavage and aldehyde dehydrogenation. The thiamine pyrophosphate dependence of the third step is unique in peroxisomal mammalian enzymology. Human pathology due to a deficient alpha-oxidation is mostly linked to mutations in the gene coding for the second enzyme of the sequence, phytanoyl-CoA hydroxylase. 相似文献
83.
Hambardzumyan A Molinari M Dumelie N Foulon L Habrant A Chabbert B Aguié-Béghin V 《Comptes rendus biologies》2011,334(11):839-850
Interfacial affinity between lignin model compound (dehydrogenation polymer [DHP]) and cellulose nanocristals (CN) was studied before building a nanocomposite cellulose/lignin in multilayer form by spin-coating method. The adsorption isotherm of DHP was measured by ellipsometry at the liquid/CN film interface and showed that the surface concentration of adsorbed DHP increases with the bulk concentration in solution. The DHP appeared as globular structures on cellulosic film, as observed by AFM. Spreading a dense lignin layer on CN film gave rise to the disappearance of the InfraRed resonance bands related to the DHP aromatics. The film obtained from alternate layers of cellulose/DHP was transparent in visible light and had weak absorption in UV wavelengths. Optical properties measured in the visible wavelength range by ellipsometry and spectrophotometry indicated that beyond six bilayers (cellulose/DHP), the composite exhibits antireflexion properties. 相似文献
84.
Loss of meiosis in Aspergillus 总被引:2,自引:0,他引:2
If strictly mitotic asexual fungi lack recombination, the conventional view
predicts that they are recent derivatives from older meiotic lineages. We
tested this by inferring phylogenetic relationships among closely related
meiotic and strictly mitotic taxa with Aspergillus conidial (mitotic)
states. Phylogenies were constructed by using DNA sequences from the
mitochondrial small ribosomal subunit, the nuclear ribosomal internal
transcribed spacers, and the nuclear 5.8S ribosomal gene. Over 920 bp of
sequence was analyzed for each taxon. Phylogenetic analysis of both the
mitochondrial and nuclear data sets showed at least four clades that
possess both meiotic and strictly mitotic taxa. These results support the
hypothesis that strictly mitotic lineages arise frequently from more
ancient meiotic lineages with Aspergillus conidial states. Many of the
strictly mitotic species examined retained characters that may be vestiges
of a meiotic state, including the production of sclerotia, sclerotium-like
structures, and hulle cells.
相似文献
85.
86.
87.
EG Ciolac SS Mantuani CM Neiva CEL Verardi DM Pess?a-Filho L Pimenta 《Biology of sport / Institute of Sport》2015,32(2):103-108
The aim of the present study was to analyse the usefulness of the 6-20 rating of perceived exertion (RPE) scale for prescribing and self-regulating high-intensity interval training (HIT) in young individuals. Eight healthy young subjects (age = 27.5±6.7 years) performed maximal graded exercise testing to determine their maximal and reserve heart rate (HR). Subjects then performed two HIT sessions (20 min on a treadmill) prescribed and regulated by their HR (HR: 1 min at 50% alternated with 1 min at 85% of reserve HR) or RPE (RPE: 1 minute at the 9-11 level [very light-fairly light] alternated with 1 minute at the 15-17 level [hard-very hard]) in random order. HR response and walking/running speed during the 20 min of exercise were compared between sessions. No significant difference between sessions was observed in HR during low- (HR: 135±15 bpm; RPE: 138±20 bpm) and high-intensity intervals (HR: 168±15 bpm; RPE: 170±18 bpm). Walking/running speed during low- (HR: 5.7±1.2 km · h−1; RPE: 5.7±1.3 km · h−1) and high-intensity intervals (HR: 7.8±1.9 km · h−1; RPE: 8.2±1.7 km · h−1) was also not different between sessions. No significant differences were observed in HR response and walking/running speed between HIT sessions prescribed and regulated by HR or RPE. This finding suggests that the 6-20 RPE scale may be a useful tool for prescribing and self-regulating HIT in young subjects. 相似文献
88.
Partial 18S rRNA sequences of five chelicerate arthropods plus a
crustacean, myriapod, insect, chordate, echinoderm, annelid, and
platyhelminth were compared. The sequence data were used to infer phylogeny
by using a maximum-parsimony method, an evolutionary-distance method, and
the evolutionary-parsimony method. The phylogenetic inferences generated by
maximum-parsimony and distance methods support both monophyly of the
Arthropoda and monophyly of the Chelicerata within the Arthropoda. These
results are congruent with phylogenies based on rigorous cladistic analyses
of morphological characters. Results support the inclusion of the
Arthropoda within a spiralian or protostome coelomate clade that is the
sister group of a deuterostome clade, refuting the hypothesis that the
arthropods represent the "primitive" sister group of a protostome coelomate
clade. Bootstrap analyses and consideration of all trees within 1% of the
length of the most parsimonious tree suggest that relationships between the
nonchelicerate arthropods and relationships within the chelicerate clade
cannot be reliably inferred with the partial 18S rRNA sequence data. With
the evolutionary-parsimony method, support for monophyly of the Arthropoda
is found in the majority of the combinations analyzed if the coelomates are
used as "outgroups." Monophyly of the Chelicerata is supported in most
combinations assessed. Our analyses also indicate that the
evolutionary-parsimony method, like distance and parsimony, may be biased
by taxa with long branches. We suggest that a previous study's inference of
the Arthropoda as paraphyletic may be the result of (a) having two few
arthropod taxa available for analysis and (b) including long-branched taxa.
相似文献
89.
90.
G Thoidis T Kupriyanova J M Cunningham P Chen S Cadel T Foulon P Cohen R E Fine K V Kandror 《The Journal of biological chemistry》1999,274(20):14062-14066
In rat brain and cultured neuroendocrine PC12 cells, Glut3 is localized at the cell surface and, also, in a distinct population of homogenous synaptic-like vesicles. Glut3-containing vesicles co-purify with "classical" synaptic vesicles, but can be separated from the latter by sucrose gradient centrifugation. Unlike classical synaptic vesicles, Glut3-containing vesicles possess a high level of aminopeptidase activity, which has been identified as aminopeptidase B. This enzyme has recently been shown to be a marker of the secretory pathway in PC12 cells (Balogh, A., Cadel, S., Foulon, T., Picart, R., Der Garabedian, A., Rousselet, A., Tougard, C., and Cohen, P. (1998) J. Cell Sci. 111, 161-169). We, therefore, conclude that Glut3 is targeted to secretory vesicles in both neurons and PC12 cells. 相似文献