144 research outputs found
A T cell receptor (TCR) antagonist competitively inhibits serial TCR triggering by low-affinity ligands, but does not affect triggering by high-affinity anti-CD3 antibodies
No full textIt has been demonstrated that modified peptides which fail to induce detectable T cell responses can act as T cell receptor (TCR) antagonists when presented together with agonist by the same antigen-presenting cell (APC). We report that a TCR antagonist competitively inhibits TCR triggering induced by low-affinity ligands such as agonistic peptides or bacterial superantigens. However, the same antagonist cannot inhibit TCR triggering and T cell activation induced by high-affinity anti-CD3 antibodies that engage most TCR at once. These results indicate that TCR antagonists inhibit T cell responses by interfering with the ongoing process of serial triggering, rather than by delivering an inhibitory signal to T cells
The genetics of Ug99 stem rust resistance in spring wheat variety ‘Linkert‘
No full textWheat stem rust caused by Puccinia graminis f. sp. tritici (Pgt) threatens wheat production worldwide. The objective of this study was to characterize wheat stem rust resistance in ‘Linkert’, a variety with adult plant resistance effective to emerging wheat stem rust pathogen strain Ug99. Two doubled haploid (DH) populations and one recombinant inbred line (RIL) population were developed with ‘Linkert’ as a stem rust resistant parent. Hard red spring wheat variety ‘Forefront’ and genetic stock ‘LMPG’ were used as stem rust susceptible parents of the DH populations. Breeding line ‘MN07098-6’ was used as a susceptible parent of the RIL population. Both DH and RIL populations with their parents were evaluated both at the seedling stage and in the field against Pgt races. Genotyping data of the DH populations were generated using the wheat iSelect 90k SNP assay. The RIL population was genotyped by genotyping-by-sequencing. We found QTL consistently associated with wheat stem rust resistance on chromosome 2BS for the Linkert/Forefront DH population and the Linkert/MN07098-6 RIL population both in Ethiopia and Kenya. Additional reliable QTL were detected on chromosomes 5BL (125.91 cM) and 4AL (Sr7a) for the Linkert/LMPG population in Ethiopia and Kenya. Different QTL identified in the populations reflect the importance of examining the genetics of resistance in populations derived from adapted germplasm (Forefront and MN07098-6) in addition to a genetic stock (LMPG). The associated markers in this study could be used to track and select for the identified QTL in wheat breeding programs
Quantitative contribution of CD4 and CD8 to T cell antigen receptor serial triggering.
No full textCD4 and CD8 are thought to function as coreceptors by binding to the cognate major histocompatibility complex (MHC) molecules recognized by the T cell antigen receptor (TCR) and initiating the signal transduction cascade. We report that during T cell-antigen-presenting cell interaction, triggered TCRs and coreceptors are downregulated and degraded with identical kinetics. This coordinated disappearance takes place whenever the TCR is triggered, even when the coreceptor does not engage the cognate MHC molecule and is the consequence of binding of the coreceptor-associated Lck to ZAP-70. The interaction of coreceptor and cognate MHC molecules is dispensable when T cells are stimulated by optimal ligands, but becomes crucial when suboptimal ligands are used. In the latter case the coreceptor increases the efficiency of TCR triggering without changing the activation threshold or the quality of the T cell response
Developmental regulation of Lck targeting to the CD8 coreceptor controls signaling in naive and memory T cells.
No full textThe question of whether enhanced memory T cell responses are simply due to an increased frequency of specific cells or also to an improved response at the single cell level is widely debated. In this study, we analyzed T cell receptor (TCR) transgenic memory T cells and bona fide memory T cells isolated from virally infected normal mice using the tetramer technology. We found that memory T cells are qualitatively different from naive T cells due to a developmentally regulated rearrangement of the topology of the signaling machinery. In naive cytotoxic T cells, only a few CD8 molecules are associated with Lck and the kinase is homogeneously distributed inside the cell. However, in vivo priming of naive T cells induces the targeting of Lck to the CD8 coreceptor in the cell membrane and the consequent organization of a more efficient TCR signaling machinery in effector and memory cells
Five years of Ulysses dust data: 2000-2004
No full textKrueger H, Altobelli N, Anweiler B, et al. Five years of Ulysses dust data: 2000-2004. Planetary and Space Science. 2006;54(9-10):932-956.The Ulysses spacecraft has been orbiting the Sun on a highly inclined ellipse (i = 79 degrees, perihelion distance 1.3 AU, aphelion distance 5.4 AU) since it encountered Jupiter in 1992. Between January 2000 and December 2004, the spacecraft completed almost an entire revolution about the Sun, passing through perihelion in May 2001 and aphelion in July 2004. In this five-year period the dust detector on board recorded 4415 dust impacts. We publish and analyse the complete data set of both raw and reduced data for particles with masses 10(-16) g <= M <= 10(-7) g. Together with. 1695 dust impacts recorded between launch of Ulysses and the end of 1999 published earlier (Grain, E., Baguhl, M., Divine, N., Fechtig, H., Hamilton, D.P, Harmer, M.S., Kissel, J., Lindblad, B.A., Linkert, D., Linkert, G., Mann, L, McDonnell, J.A.M., Morfill, G.E., Polanskey, C., Riemann, R., Schwehm, G.H., Siddique, N., Staubach, P., Zook, H.A., 1995a. Two years of Ulysses dust data. Planetary Space Sci. 43, 971-999, Paper III; Kruger, H., Grun, E., Landgraf, M., Baguhl, M., Dermott, S.F., Fechtig, H., Gustafson, B.A., Hamilton, D.P., Harmer, M.S., Horanyi, M., Kissel, J., Lindblad, B., Linkert, D., Linkert, G., Mann, L, McDonnell, J.A.M., Morfill, G.E., Polanskey, C., Schwehm, G.H., Srama, R., Zook, H.A., 1995. Three years of Ulysses dust data: 1993 to 1995. Planetary and Space Sci. 47, 363-383, Paper V; Kruger, H., Grun, E., Landgraf, M., Dermott, S.F., Fechtig, H., Gustafson, B.A., Hamilton, D.P., Harmer, M.S., Horanyi, M., Kissel, J., Lindblad, B., Linkert, D., Linkert, G., Mann, I., McDonnell, J.A.M., Morfill, G.E., Polanskey, C., Schwehm, G.H., Srama, R., Zook, H.A., 2001b. Four years of Ulysses dust data: 1996 to 1999. Planetary Space Sci. 49, 1303-1324, Paper VII), a data set of 6110 dust impacts detected with the Ulysses sensor between October 1990 and December 2004 is now available. The impact rate measured between 2000 and 2002 was relatively constant with about 0.3 impacts per day showing a maximum at 1.5 per day around ecliptic plane crossing in early-2001. The impact direction of the majority of impacts between 2000 and 2002 is compatible with particles of interstellar origin, the rest are most likely interplanetary particles. In 2003 and 2004 dust stream particles originating from the jovian system dominated the overall impact rate. Twenty-two individual dust streams were measured between November 2002 and December 2004. The observed impact rates are compared with models for interplanetary and interstellar dust. The dust measurements from the entire mission since Ulysses launch give good agreement with the interplanetary flux model of Staubach, P., Grun, E., Jehn, R., 1997. The meteoroid environment near Earth, Adv. Space Res. 19, 301-308. (c) 2006 Elsevier Ltd. All rights reserved
ChemInform Abstract: Intramolecular Hetero-Diels-Alder Reaction of Prolinal-Derived N- Arylimines Lewis Acid-Dependent Reversal of the Diastereoselectivity.
No full textChemInform Abstract: Chelation Control by a Second Nitrogen Atom in Formal Hetero Diels- Alder Reactions of N-Arylimines.
No full textChemInform Abstract: Evidence for a Stepwise Mechanism in Formal Hetero-Diels-Alder Reactions of N-Arylimines.
No full textPENGARUH GAYA KEPEMIMPINAN TERHADAP KINERJA PADA BADAN PENGAWAS PEMILIHAN UMUM KAB. INHIL
No full textThis study discusses how leadership styles influence performance. Data obtained through surveys by disseminating questionnaire with linkert measurement scale to 31 respondents in BAWASLU who is located at Jalan Baharuddin Yusuf No.10 Tembilahan Kota. Sampling technique the technique used is convience sampling while the analytical tools used is a simple linear regression and is processed using t test using SPSS.20
From the results of this study the authors find out the influence of leadership style an (x) with respect to performance (y). With a style hypothesis leadership has no positive influence and does not signifakan on the performance of Bawaslu. Based onThe results of data analysis and hypothesis testing denbro, the result of R Squareof 0.030 or 3% leadership stylen affect performanceand Sthe term97% performanceinfluenced by factors-another factor. The author suggests toresearch next to conduct research in other organizations, with scope expanded research
Analisa Persepsi Masyarakat Terhadap Dampak Lingkungan Usaha Sapi Perah di Kecamatan Pancoran
No full textThe dairy cattle business in DKI Jakarta has been hereditary and has been increasing. This increase also has an impact on the environment around the farm, including pollution due to unpleasant odors, water pollution, soil pollution and the presence of annoying flies. The public's perception of the dairy business is very diverse, therefore the author conducted an analysis of the public's perception of the dairy business. Data collection was carried out in Pancoran District, South Jakarta, DKI Jakarta. Data was obtained through distributing questionnaires to residents and after interviews were processed using the ultrasound method and Linkert Scale. From the results of data processing, it was found that the community was disturbed by pollution due to unpleasant odors, water pollution, soil pollution and the presence of annoying flies. The proposal to overcome environmental impacts is made by turning cow faeces into organic fertilizer and biogas. Handling environmental impacts well can have a social impact and also provide many benefits to the surrounding community
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