Proteins which are secreted or associated with the cell envelope of Mycobacterium tuberculosis may contain protective T-cell epitopes. Prior to this study, a recombinant clone bank of enzymatically active M. tuberculosis-alkaline phosphatase fusions, were screened for immunogenicity in a murine T-cell model. Five of these were selected for further study, and the IFN-gamma secretion and proliferation of human PBMC from purified protein derivative- (PPD)-positive and PPD-negative donors were measured in response to oligopeptides, Mtb-PhoA fusions and one full-length protein. Epitopes from four of the five selected antigens were immunoreactive in the human model and corresponded to cytochrome d ubiquinol oxidase, cytochrome c oxidase subunit II, MTV005.02 and MTV033.08. Thus, this strategy identified novel human immunogenic peptides as possible candidates for a subunit vaccine. 相似文献
Patterns of O2 evolution resulting from sequences of short flashes are reported for Photosystem (PS) II preparations isolated from spinach and containing an active, O2-evolving system. The results can be interpreted in terms of the S-state model developed to explain the process of photosynthetic water splitting in chloroplasts and algae. The PS II samples display damped, oscillating patterns of O2 evolution with a period of four flashes. Unlike chloroplasts, the flash yields of the preparations decay with increasing flash number due to the limited plastoquinone acceptor pool on the reducing side of PS II. The optimal pH for O2 evolution in this system (pH 5.5–6.5) is more acidic than in chloroplasts (pH 6.5–8.0). The O2-evolution, inactivation half-time of dark-adapted preparations was 91 min (on the rate electrode) at room temperature. Dark-inactivation half-times of 14 h were observed if the samples were aged off the electrode at room temperature. Under our conditions (experimental conditions can influence flash-sequence results), deactivation of S3 was first order with a half-time of 105 s while that of S2 was biphasic. The half-times for the first-order rapid phase were 17 s (one preflash) and 23 s (two preflashes). The longer S2 phase deactivated very slowly (the minimum half-time observed was 265 s). These results indicate that deactivation from S3 → S2 → S1, thought to be the dominant pathway in chloroplasts, is not the case for PS II preparations. Finally, it was demonstrated that the ratio of S1 to S0 can be set by previously developed techniques, that S0 is formed mostly from activated S3 (S4), and that both S0 and S1 are stable in the dark. 相似文献
Functional coupling of the human thrombin receptor PAR1 (protease-activated receptor 1) with the retinal rod G-protein transducin (Gt, a member of the Gi family) was studied in a reconstituted system of membranes from Sf9 cells expressing the thrombin receptor and purified Gt from bovine rod outer segments. TRAP6-agonist-activated PAR1 interacts productively with the distant G-protein. Agonist-dependent Gt activation was measured using a real-time fluorimetric GTP[S]-binding assay and membranes from Sf9 cells. To characterize nucleotide-exchange catalysis by PAR1, we analyzed dependence on nucleotides, temperature and pH. Activation was inhibited by low GDP concentrations (IC50 = 5.2 +/- 1.5 microM at 5 microM GTP[S]), indicating that receptor-Gt coupling, followed by instantaneous GDP release, is rate limiting under the conditions (25 degrees C). Arrhenius plots of the temperature dependence reflect an apparent Ea of 60 +/- 3.5 kJ.mol-1. Evaluation of the pH/rate profiles of Gt activation indicates that the activating conformation of the receptor is determined by protonation of a titratable group with an apparent pKa of 6.4. This supports the idea that the active state of agonist-bound PAR1 depends on forced protonation, indicating possible analogies to the scheme established for rhodopsin. 相似文献
iSERS (SERS=surface‐enhanced Raman scattering) microscopy is an emerging Raman‐based staining technique for the selective localization of target proteins on cells and tissues using antibody‐ SERS nanotag conjugates. In this contribution we demonstrate the feasibility of iSERS for imaging of programmed cell death‐ligand 1 (PD‐L1), an important predictive biomarker, on single SkBr‐3 breast cancer cells. Further details can be found in the article by Elzbieta Stepula, Matthias König, Xin‐Ping Wang, et al. ( e201960034 ).
Abstract LCA-CPG-nucleoside 5′-O-(O-β-cyanoethyl-H-phosphonates) react with 3′-amino-2′,3′-dideoxynucleoside in the presence of iodine giving in a high yield N3′→P5′ phosphoramidate oligonucleotides. 相似文献
As individuals with problematic alcohol consumption are hardly reached by the treatment system, measures of early intervention in the primary health care system are promising. However, counseling strategies such as Motivational Interviewing that have been proven to be effective are rarely conducted. Lack of time is mentioned by physicians as a main barrier for conducting brief interventions. New technologies allow the development of economic and individualized prevention strategies. This paper presents the computerized Expert-test and Guide [“Ratgeber”] for Alcohol use (ExtrA), a prevention program for at-risk drinking. Data on the efficacy of this approach in proactively recruited samples are described and possible conclusions for the usability of new technologies for interventions with a high population impact are presented. 相似文献
For the biogenesis of mitochondria, hundreds of proteins need to be targeted from the cytosol into the various compartments of this organelle. The intramitochondrial targeting routes these proteins take to reach their respective location in the organelle are well understood. However, the early targeting processes, from cytosolic ribosomes to the membrane of the organelle, are still largely unknown. In this study, we present evidence that an integral membrane protein of the endoplasmic reticulum (ER), Ema19, plays a role in this process. Mutants lacking Ema19 show an increased stability of mitochondrial precursor proteins, indicating that Ema19 promotes the proteolytic degradation of nonproductive precursors. The deletion of Ema19 improves the growth of respiration-deficient cells, suggesting that Ema19-mediated degradation can compete with productive protein import into mitochondria. Ema19 is the yeast representative of a conserved protein family. The human Ema19 homologue is known as sigma 2 receptor or TMEM97. Though its molecular function is not known, previous studies suggested a role of the sigma 2 receptor as a quality control factor in the ER, compatible with our observations about Ema19. More globally, our data provide an additional demonstration of the important role of the ER in mitochondrial protein targeting. 相似文献