36 research outputs found

    Rearrangement of the RNA polymerase subunit H and the lower jaw in archaeal elongation complexes

    Get PDF
    The lower jaws of archaeal RNA polymerase and eukaryotic RNA polymerase II include orthologous subunits H and Rpb5, respectively. The tertiary structure of H is very similar to the structure of the C-terminal domain of Rpb5, and both subunits are proximal to downstream DNA in pre-initiation complexes. Analyses of reconstituted euryarchaeal polymerase lacking subunit H revealed that H is important for open complex formation and initial transcription. Eukaryotic Rpb5 rescues activity of the ΔH enzyme indicating a strong conservation of function for this subunit from archaea to eukaryotes. Photochemical cross-linking in elongation complexes revealed a striking structural rearrangement of RNA polymerase, bringing subunit H near the transcribed DNA strand one helical turn downstream of the active center, in contrast to the positioning observed in preinitiation complexes. The rearrangement of subunits H and A′′ suggest a major conformational change in the archaeal RNAP lower jaw upon formation of the elongation complex

    Rgs2 Mediates Pro-Angiogenic Function of Myeloid Derived Suppressor Cells in the Tumor Microenvironment via Upregulation of MCP-1

    Get PDF
    Tumor growth is intimately linked with stromal interactions. Myeloid derived suppressor cells (MDSCs) are dramatically elevated in cancer patients and tumor bearing mice. MDSCs modulate the tumor microenvironment through attenuating host immune response and increasing vascularization.In searching for molecular mediators responsible for pro-tumor functions, we found that regulator of G protein signaling-2 (Rgs2) is highly increased in tumor-derived MDSCs compared to control MDSCs. We further demonstrate that hypoxia, a common feature associated with solid tumors, upregulates the gene expression. Genetic deletion of Rgs2 in mice resulted in a significant retardation of tumor growth, and the tumors exhibit decreased vascular density and increased cell death. Interestingly, deletion of Rgs2 in MDSCs completely abolished their tumor promoting function, suggesting that Rgs2 signaling in MDSCs is responsible for the tumor promoting function. Cytokine array profiling identified that Rgs2-/- tumor MDSCs produce less MCP-1, leading to decreased angiogenesis, which could be restored with addition of recombinant MCP-1.Our data reveal Rgs2 as a critical regulator of the pro-angiogenic function of MDSCs in the tumor microenvironment, through regulating MCP-1 production

    The Speed of Sound in Methane under Conditions of the Thermal Boundary Layer of Uranus

    Full text link
    We present the first direct observations of acoustic waves in warm dense matter. We analyze wavenumber- and energy-resolved X-ray spectra taken from warm dense methane created by laser-heating a cryogenic liquid jet. X-ray diffraction and inelastic free electron scattering yield sample conditions of 0.3±\pm0.1 eV and 0.8±\pm0.1 g/cm3^3, corresponding to a pressure of \sim13 GPa and matching the conditions predicted in the thermal boundary layer between the inner and outer envelope of Uranus. Inelastic X-ray scattering was used to observe the collective oscillations of the ions. With a highly improved energy resolution of \sim50 meV, we could clearly distinguish the Brillouin peaks from the quasi-elastic Rayleigh feature. Data at different wavenumbers were used to obtain a sound speed of 5.9±\pm0.5 km/s, which enabled us to validate the use of Birch's law in this new parameter regime.Comment: 7 pages, 4 figures with supplementary informatio

    A model for predicting effect of treatment on progression-free survival using MRD as a surrogate end point in CLL

    Get PDF
    Our objective was to evaluate minimal residual disease (MRD) at the end of induction treatment with chemoimmunotherapy as a surrogate end point for progression-free survival (PFS) in chronic lymphocytic leukemia (CLL) based on 3 randomized, phase 3 clinical trials (ClinicalTrials.gov identifiers NCT00281918, NCT00769522, and NCT02053610). MRD was measured in peripheral blood (PB) from treatment-naïve patients in the CLL8, CLL10, and CLL11 clinical trials, and quantified by 4-color flow cytometry or allele-specific oligonucleotide real-time quantitative polymerase chain reaction. A meta-regression model was developed to predict treatment effect on PFS using treatment effect on PB-MRD. PB-MRD levels were measured in 393, 337, and 474 patients from CLL8, CLL10, and CLL11, respectively. The model demonstrated a statistically significant relationship between treatment effect on PB-MRD and treatment effect on PFS. As the difference between treatment arms in PB-MRD response rates increased, a reduction in the risk of progression or death was observed; for each unit increase in the (log) ratio of MRD2 rates between arms, the log of the PFS hazard ratio decreased by 20.188 (95% confidence interval, 20.321 to 20.055; P 5 .008). External model validation on the REACH trial and sensitivity analyses confirm the robustness and applicability of the surrogacy model. Our surrogacy model supports use of PB-MRD as a primary end point in randomized clinical trials of chemoimmunotherapy in CLL. Additional CLL trial data are required to establish a more precise quantitative relationship between MRD and PFS, and to support general applicability of MRD surrogacy for PFS across diverse patient characteristics, treatment regimens, and different treatment mechanisms of action

    Mitochondrial physiology

    Get PDF
    As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

    Mitochondrial physiology

    Get PDF
    As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

    "Ska vi arbeta hårdast eller smartast?" : En kvalitativ studie med fokus på IT-företag i Växjö och deras arbete med processinnovationer  

    No full text
    Titel: “Ska vi arbeta hårdast eller smartast?” – En kvalitativ studie med fokus på IT-företag i Växjö och deras arbete med processinnovationer.  Bakgrund: Företag arbetar dagligen i processer. Det blir väsentligt för företag att utveckla sina processer för att säkerställa att de bedriver sitt arbete på det mest effektiva arbetssättet - med fokus på att arbeta smartare snarare än hårdare. Processinnovationer innebär att vara innovativ med fokus på att förändra sina befintliga processer och dess arbetssätt för att säkerställa effektiva processer. Resultatet av processinnovationer kan exempelvis innebära minskade kostnader, tidsbesparing och ökat kundvärde. IT-branschen har visat sig vara den mest innovationsaktiva bransch i Sverige där processinnovationer var den mest förekommande.  Syfte och problemformulering: Syftet med studien är att skapa förståelse kring hur IT- företag i Växjö arbetar med processinnovationer. Studiens två problemformuleringar är: 1. Hur bedrivs processinnovationer på IT-företag i Växjö? 2. Vilka likheter respektive skillnader går att identifiera i processinnovationerna på IT-företag i Växjö?  Teori: Den teoretiska referensramen bygger på processinnovation med stöd av genomgång av innovation och processer. Dessutom görs en djupare redogörelse för centrala och essentiella delar inom arbetet med processinnovationer: öppenhet, samarbete, processkartläggning och IT-system vid processinnovationer.  Metod: Studien bygger på en fallstudiedesign med tre fall (tre IT-företag i Växjö). Den empiriska insamlingen bestod av totalt elva semistrukturerade intervjuer med representanter fördelat mellan studiens tre företag. Urvalet av respondenter gjordes via ett målstyrt urval och snöbollsurval för att säkerställa medverkande respondenter som hade inblick i företagens arbete med processinnovationer.  Slutsats: Resultatet av studien visar att samtliga företag arbetar tydligt och strukturerat med processinnovation. Vi har kunnat skapa en god förståelse samt kunskap om arbetssättet kring processinnovationer på IT-företag i Växjö. Studien har även identifierat likheter och skillnader kring företagens arbetssätt vid processinnovationer.
    corecore