660 research outputs found
Is Safe Agile Portfolio Management Compatible With COBIT?
Background. Software development companies leverage various agile practices to remain flex- ible in dynamically developing markets. The iterative nature of Agile introduces new challenges at the portfolio management level. Yet, the research on Agile portfolio management has enjoyed limited research interest. Aim. Describe how traditional management approaches can leverage existing agile portfolio management practices and concepts. Method. Conceptual Analysis with mapping of SAFe portfolio management concepts and COBIT 2019. Results. Portfolio man- agement concepts from SAFe which the COBIT 2019 practitioners can leverage. Conclusion. Using the frameworks SAFe and COBIT combined is not yet ready for implementation. Rec- ommendation. Introduce new COBIT’s focus area so that the agile concepts can be leveraged
Unravelling metabolism of Leishmania by metabolomics
The leishmaniases are neglected tropical diseases with an urgent need for effective drugs. Better understanding of the metabolism of the causative parasites will hopefully lead to development of new compounds targeted at critical points of the parasite’s biochemical pathways. In my work I focused on the pentose phosphate pathway of Leishmania, specifically on transketolase, sugar utilisation, and comparison between insect and mammalian infective stages of the parasites.
The pentose phosphate pathway (PPP) is the major cellular source of NADPH, an agent critical for oxidative stress defence. The PPP uses glucose, reduces the NADP+ cofactor and produces various sugar phosphates by mutual interconversions. One of the enzymes involved in this latter part is transketolase (TKT). A Leishmania mexicana cell line deleted in transketolase (Δtkt) was assessed regarding viability, sensitivity to a range of drugs, changes in metabolism, and infectivity. The Δtkt cell line had no obvious growth defect in the promastigote stage, but it was more sensitive to an oxidative stress inducing agent and most of the drugs tested. Most importantly, the Δtkt cells were not infective to mice, establishing TKT as a new potential drug target.
Metabolomic analyses revealed multiple changes as a consequence of TKT deletion. Levels of the PPP intermediates upstream of TKT increased substantially, and were diverted into additional reactions. The perturbation triggered further changes in metabolism, resembling the ‘stringent metabolic response’ of amastigotes. The Δtkt cells consumed less glucose and glycolytic intermediates were decreased indicating a decrease in flux, and metabolic end products were diminished in production. The decrease in glycolysis was possibly caused by inhibition of fructose-1,6-bisphosphate aldolase by accumulation of the PPP intermediates 6-phosphogluconate and ribose 5-phosphate. The TCA cycle was fuelled by alternative carbon sources, most likely amino acids, instead of glucose. It remains unclear why deletion of TKT is lethal for amastigotes, increased sensitivity to oxidative stress or drop in mannogen levels may contribute, but no definite conclusions can be made.
TKT localisation indicated interesting trends too. The WT enzyme is present in the cytosol and glycosomes, whereas a mutant version, truncated by ten amino acids, but retaining a C-terminal targeting sequence, localised solely to glycosomes. Surprisingly, cells expressing purely cytosolic or glycosomal TKT did not have different phenotypes regarding growth, oxidative stress sensitivity or any detected changes in metabolism. Hence, control of the subcellular localisation remains unclear as well as its function. However, these data are in agreement with the presumed semipermeable nature of the glycosome.
Further, L. mexicana promastigote cultures were grown in media with different combinations of labelled glucose and ribose and their incorporation into metabolism was followed. Glucose was the preferred carbon source, but when not available, it could be fully replaced with ribose.
I also compared metabolic profiles from splenic amastigotes, axenic amastigotes and promastigotes of L. donovani. Metabolomic analysis revealed a substantial drop in amino acids and other indications coherent with a stringent metabolic response in amastigotes. Despite some notable differences, axenic and splenic amastigotes demonstrated fairly similar results both regarding the total metabolic profile and specific metabolites of interest
Das deutsche und tschechische Phonemsystem aus kontrastiver Sicht - Erfahrungen aus dem Phonetikunterricht und der Arbeit mit künftigen Deutschlehrern
Aus dem Vergleich der Lautsysteme der deutschen und der tschechischen
Sprache können Phoneme ermittelt werden, die im Tschechischen nicht vorkommen und den tschechischen Muttersprachlern Schwierigkeiten bei der Aussprache auf der segmentalen Ebene bereiten. Besondere Aufmerksamkeit muss jedoch den Unterschieden im suprasegmentalen Bereich gewidmet werden, da das Deutsche eine akzentzählende, das Tschechische eine silbenzählende Sprache ist. Bei der Ausbildung künftiger Deutschlehrer wird großer Wert nicht nur auf die Einübung einer korrekten Aussprache des Deutschen, sondern auch auf die Methodik zur Behebung der häufigsten Aussprachefehler gelegt
Challenges in cancer research and multifaceted approaches for cancer biomarker quest
AbstractRecent advances in cancer biology have subsequently led to the development of new molecularly targeted anti-cancer agents that can effectively hit cancer-related proteins and pathways. Despite better insight into genomic aberrations and diversity of cancer phenotypes, it is apparent that proteomics too deserves attention in cancer research. Currently, a wide range of proteomic technologies are being used in quest for new cancer biomarkers with effective use. These, together with newer technologies such as multiplex assays could significantly contribute to the discovery and development of selective and specific cancer biomarkers with diagnostic or prognostic values for monitoring the disease state. This review attempts to illustrate recent advances in the field of cancer biomarkers and multifaceted approaches undertaken in combating cancer
PGE2 Promotes Apoptosis Induced by Cytokine Deprivation through EP3 Receptor and Induces Bim in Mouse Mast Cells
Increased mast cell numbers are observed at sites of allergic inflammation and restoration of normal mast cell numbers is critical to the resolution of these responses. Early studies showed that cytokines protect mast cells from apoptosis, suggesting a simple model in which diminished cytokine levels during resolution leads to cell death. The report that prostaglandins can contribute both to recruitment and to the resolution of inflammation together with the demonstration that mast cells express all four PGE2 receptors raises the question of whether a single PGE2 receptor mediates the ability of PGE2 to regulate mast cell survival and apoptosis. We report here that PGE2 through the EP3 receptor promotes cell death of mast cells initiated by cytokine withdrawal. Furthermore, the ability of PGE2 to limit reconstitution of tissues with cultured mast cells is lost in cell lacking the EP3 receptor. Apoptosis is accompanied by higher dissipation of mitochondrial potential (ΔΨm), increased caspase-3 activation, chromatin condensation, and low molecular weight DNA cleavage. PGE2 augmented cell death is dependent on an increase in intracellular calcium release, calmodulin dependent kinase II and MAPK activation. Synergy between the EP3 pathway and the intrinsic mitochondrial apoptotic pathway results in increased Bim expression and higher sensitivity of mast cells to cytokine deprivation. This supports a model in which PGE2 can contribute to the resolution of inflammation in part by augmenting the removal of inflammatory cells in this case, mast cells
Enhanced mast cell activation in mice deficient in the A2b adenosine receptor
Antigen-mediated cross-linking of IgE bound to mast cells via the high affinity receptor for IgE triggers a signaling cascade that results in the release of intracellular calcium stores, followed by an influx of extracellular calcium. The collective increase in intracellular calcium is critical to the release of the granular contents of the mast cell, which include the mediators of acute anaphylaxis. We show that the sensitivity of the mast cell to antigen-mediated degranulation through this pathway can be dramatically influenced by the A2b adenosine receptor. Loss of this Gs-coupled receptor on mouse bone marrow–derived mast cells results in decreased basal levels of cyclic AMP and an excessive influx of extracellular calcium through store-operated calcium channels following antigen activation. Mice lacking the A2b receptor display increased sensitivity to IgE-mediated anaphylaxis. Collectively, these findings show that the A2b adenosine receptor functions as a critical regulator of signaling pathways within the mast cell, which act in concert to limit the magnitude of mast cell responsiveness when antigen is encountered
Cholesterol deficiency in a mouse model of Smith-Lemli-Opitz syndrome reveals increased mast cell responsiveness
Mutation of the 3β-hydroxysterol Δ7-reductase gene (Dhcr7−/−) results in Smith-Lemli-Opitz syndrome (SLOS). Patients, and genetically altered mice, are unable to produce cholesterol and accumulate 7-dehydrocholesterol (DHC) in serum and tissue. This causes multiple growth and developmental abnormalities as well as immune system anomalies including allergy. Because cholesterol is a key component of liquid-ordered membranes (lipid rafts) and these domains have been implicated in regulating mast cell activation, we examined whether mast cell responsiveness is altered in this model. Mast cells derived from Dhcr7−/− mice (DHCR KO) showed constitutive cytokine production and hyper-degranulation after stimulation of the high affinity IgE receptor (FcɛRI). DHCR KO mast cells, but not wild-type mast cells, accumulated DHC in lipid rafts. DHC partially disrupted lipid raft stability and displaced Lyn kinase protein and activity from lipid rafts. This led to down-regulation of some Lyn-dependent signaling events but increased Fyn kinase activity and Akt phosphorylation. The Lyn-dependent phosphorylation of Csk-binding protein, which negatively regulates Fyn activity, was decreased. This phenotype reproduces some of the characteristics of Lyn-null mast cells, which also demonstrate hyper-degranulation. These findings provide the first evidence of lipid raft dysfunction in SLOS and may explain the observed association of allergy with SLOS
Efficient Inhibition of HIV Replication in the Gastrointestinal and Female Reproductive Tracts of Humanized BLT Mice by EFdA
The nucleoside reverse transcriptase inhibitor (NRTI) 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA) in preclinical development exhibits improved safety and antiviral activity profiles with minimal drug resistance compared to approved NRTIs. However, the systemic antiviral efficacy of EFdA has not been fully evaluated. In this study, we utilized bone marrow/liver/thymus (BLT) humanized mice to investigate the systemic effect of EFdA treatment on HIV replication and CD4+ T cell depletion in the peripheral blood (PB) and tissues. In particular, we performed a comprehensive analysis of the female reproductive tract (FRT) and gastrointestinal (GI) tract, major sites of transmission, viral replication, and CD4+ T cell depletion and where some current antiretroviral drugs have a sub-optimal effect
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