805 research outputs found

    Alpha-1 Antitrypsin is Markedly Decreased Following Pulmonary F. tularensis Challenge

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    Neutrophils form the first line of defense during infection and are indispensable in this function. The neutrophil elastase is a key effector molecule of the innate immune system with potent antimicrobial activity against Gram-negative bacteria, spirochaetes, and fungi. However, the release of neutrophil elastase during bacterial infection must be checked otherwise its release in the extracellular milieu will result in damage to surrounding tissues. Alpha-1 antitrypsin is a small glycoprotein clade A serpine serine protease inhibitor and has been shown to increase in humans following bacterial and viral infection. Francisella tularensis is a Gram-negative facultative intracellular bacterium and the causative agent of tularemia. Type A strains are the most virulent with an infectious dose as low as 10 colony forming units and a mortality rate of 30–60% among untreated cases of pneumonic tularemia. We report here significant reduction of this major inhibitor of the neutrophil elastase in plasma of F. tularensis LVS and F. tularensis (type A) SCHU S4 infected animals following pulmonary challenge. Associated with an imbalance of protease–antiprotease function at the alveolar level in lungs of infected animals, increased elastase activity was observed in lung lavage fluids accompanied by decrease lung function, i.e., loss of lung elastance with concomitant increase of pulmonary hysteresivity. Consistent with a competent acute phase response following F. tularensis LVS and F. tularensis (type A) SCHU S4 pulmonary challenge and proposed up-regulation of plasma haptoglobin during the course of the acute phase reaction, haptoglobin was observed significantly increased. These data suggest that unchecked neutrophil serine protease activity may arise from F. tularensis targeted reduction of plasma α(1)-antitrysin promoting lung tissue damage facilitating increased dissemination of this bacterium in infected animals

    The Indo-U.S. Library of Coude Feed Stellar Spectra

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    We have obtained spectra for 1273 stars using the 0.9m Coud\'e Feed telescope at Kitt Peak National Observatory. This telescope feeds the coud\'e spectrograph of the 2.1m telescope. The spectra have been obtained with the #5 camera of the coud\'e spectrograph and a Loral 3K X 1K CCD. Two gratings have been used to provide spectral coverage from 3460 \AA to 9464 \AA, at a resolution of \sim1\AA FWHM and at an original dispersion of 0.44 \AA/pixel. For 885 stars we have complete spectra over the entire 3460 \AA to 9464 \AA wavelength region (neglecting small gaps of << 50 \AA), and partial spectral coverage for the remaining stars. The 1273 stars have been selected to provide broad coverage of the atmospheric parameters Teff_{eff}, log g, and [Fe/H], as well as spectral type. The goal of the project is to provide a comprehensive library of stellar spectra for use in the automated classification of stellar and galaxy spectra and in galaxy population synthesis. In this paper we discuss the characteristics of the spectral library, viz., details of the observations, data reduction procedures, and selection of stars. We also present a few illustrations of the quality and information available in the spectra. The first version of the complete spectral library is now publicly available from the National Optical Astronomy Observatory (NOAO) via FTP and HTTP.Comment: 18 pages, 6 figures, 4 table

    LuxS Coexpression Enhances Yields of Recombinant Proteins in Escherichia coli in Part through Posttranscriptional Control of GroEL

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    Cell-to-cell communication, or quorum sensing (QS), enables cell density-dependent regulation of bacterial gene expression which can be exploited for the autonomous-signal-guided expression of recombinant proteins (C. Y. Tsao, S. Hooshangi, H. C. Wu, J. J. Valdes, and W. E. Bentley, Metab. Eng. 12:291-297, 2010). Earlier observations that the metabolic potential of Escherichia coli is conveyed via the QS signaling molecule autoinducer-2 (AI-2) suggested that the capacity for protein synthesis could also be affected by AI-2 signaling (M. P. DeLisa, J. J. Valdes, and W. E. Bentley, J. Bacteriol. 183:2918-2928, 2001). In this work, we found that simply adding conditioned medium containing high levels of AI-2 at the same time as inducing the synthesis of recombinant proteins doubled the yield of active product. We have hypothesized that AI-2 signaling “conditions” cells as a natural consequence of cell-to-cell communication and that this could tweak the signal transduction cascade to alter the protein synthesis landscape. We inserted luxS (AI-2 synthase) into vectors which cosynthesized proteins of interest (organophosphorus hydrolase [OPH], chloramphenicol acetyltransferase [CAT], or UV-variant green fluorescent protein [GFPuv]) and evaluated the protein expression in luxS-deficient hosts. In this way, we altered the level of luxS in the cells in order to “tune” the synthesis of AI-2. We found conditions in which the protein yield was dramatically increased. Further studies demonstrated coincident upregulation of the chaperone GroEL, which may have facilitated higher yields and is shown for the first time to be positively regulated at the posttranscriptional level by AI-2. This report is the first to demonstrate that the protein synthesis capacity of E. coli can be altered by rewiring quorum sensing circuitry

    RNA Interference mediated knockdown of genes in order to increase protein production using the baculovirus expression system

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    The baculovirus expression system has proven to be a robust and versatile system for recombinant protein production in insect cells. A wide range of promoters is available for the facile expression of transgenes, and yields of up to 50% of total protein have been reported. However, in many cases yield is decreased as a result of proteases and host cell apoptosis. Past efforts to overcome this problem include co-expressing chaperone proteins to assist with folding, anti-apoptotic proteins to reduce cell death, or adding chemical protease inhibitors to the culture media. However, these methods may have non-specific effects, prove too costly to be practical, or impose an undue metabolic burden on an already stressed cell. An alternative approach to increasing protein production is through the application of RNA interference (RNAi) to knockdown viral and host genes responsible for decreasing the yield of recombinant protein. Potential targets include proteases, cell-death proteins, and cell cycle regulators. By altering the metabolic landscape of cells prior to the introduction of the baculovirus, protein production can be improved.https://doi.org/10.1186/1475-2859-5-S1-P1

    Brain-predicted age difference mediates the association between PROMIS sleep impairment, and self-reported pain measure in persons with knee pain

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    Knee pain, the most common cause of musculoskeletal pain (MSK), constitutes a severe public health burden. Its neurobiological causes, however, remain poorly understood. Among many possible causes, it has been proposed that sleep problems could lead to an increase in chronic pain symptomatology, which may be driven by central nervous system changes. In fact, we previously found that brain cortical thickness mediated the relationship between sleep qualities and pain severity in older adults with MSK. We also demonstrated a significant difference in a machine-learning-derived brain-aging biomarker between participants with low-and high-impact knee pain. Considering this, we examined whether brain aging was associated with self-reported sleep and pain measures, and whether brain aging mediated the relationship between sleep problems and knee pain. Exploratory Spearman and Pearson partial correlations, controlling for age, sex, race and study site, showed a significant association of brain aging with sleep related impairment and self-reported pain measures. Moreover, mediation analysis showed that brain aging significantly mediated the effect of sleep related impairment on clinical pain and physical symptoms. Our findings extend our prior work demonstrating advanced brain aging among individuals with chronic pain and the mediating role of brain-aging on the association between sleep and pain severity. Future longitudinal studies are needed to further understand whether the brain can be a therapeutic target to reverse the possible effect of sleep problems on chronic pain

    New species of Ehrlichia isolated from Rhipicephalus (Boophilus) microplus shows an ortholog of the E. canis major immunogenic glycoprotein gp36 with a new sequence of tandem repeats

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    Background: Ehrlichia species are the etiological agents of emerging and life-threatening tick-borne human zoonoses that inflict serious and fatal infections in companion animals and livestock. The aim of this paper was to phylogeneticaly characterise a new species of Ehrlichia isolated from Rhipicephalus (Boophilus) microplus from Minas Gerais, Brazil. Methods: The agent was isolated from the hemolymph of Rhipicephalus (B.) microplus engorged females that had been collected from naturally infested cattle in a farm in the state of Minas Gerais, Brazil. This agent was then established and cultured in IDE8 tick cells. The molecular and phylogenetic analysis was based on 16S rRNA, groEL, dsb, gltA and gp36 genes. We used the maximum likelihood method to construct the phylogenetic trees. Results: The phylogenetic trees based on 16S rRNA, groEL, dsb and gltA showed that the Ehrlichia spp isolated in this study falls in a clade separated from any previously reported Ehrlichia spp. The molecular analysis of the ortholog of gp36, the major immunoreactive glycoproteins in E. canis and ortholog of the E. chaffeensis gp47, showed a unique tandem repeat of 9 amino acids (VPAASGDAQ) when compared with those reported for E. canis, E. chaffeensis and the related mucin-like protein in E. ruminantium. Conclusions: Based on the molecular and phylogenetic analysis of the 16S rRNA, groEL, dsb and gltA genes we concluded that this tick-derived microorganism isolated in Brazil is a new species, named E. mineirensis (UFMG-EV), with predicted novel antigenic properties in the gp36 ortholog glycoprotein. Further studies on this new Ehrlichia spp should address questions about its transmissibility by ticks and its pathogenicity for mammalian hosts

    Identification of Plasmodium falciparum Translation Initiation eIF2 beta Subunit: Direct Interaction with Protein Phosphatase Type 1

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    Protein phosphatase 1 (PP1c) is one of the main phosphatases whose function is shaped by many regulators to confer a specific location and a selective function for this enzyme. Here, we report that eukaryotic initiation factor 2β of Plasmodium falciparum (PfeIF2β) is an interactor of PfPP1c. Sequence analysis of PfeIF2β revealed a deletion of 111 amino acids when compared to its human counterpart and the presence of two potential binding motifs to PfPP1 ((29)FGEKKK(34), (103)KVAW(106)). As expected, we showed that PfeIF2β binds PfeIF2γ and PfeIF5, confirming its canonical interaction with partners of the translation complex. Studies of the PfeIF2β-PfPP1 interaction using wild-type, single and double mutated versions of PfeIF2β revealed that both binding motifs are critical. We next showed that PfeIF2β is able to induce Germinal Vesicle Break Down (GVBD) when expressed in Xenopus oocytes, an indicator of its capacity to regulate PP1. Only combined mutations of both binding motifs abolished the interaction with PP1 and the induction of GVBD. In P. falciparum, although the locus is accessible for genetic manipulation, PfeIF2β seems to play an essential role in intraerythrocytic cycle as no viable knockout parasites were detectable. Interestingly, as for PfPP1, the subcellular fractionation of P. falciparum localized PfeIF2β in cytoplasm and nuclear extracts, suggesting a potential effect on PfPP1 in both compartments and raising the question of a non-canonical function of PfeIf2β in the nucleus. Hence, the role played by PfeIF2β in blood stage parasites could occur at multiple levels involving the binding to proteins of the translational complex and to PfPP1

    Dynamical Measurements of Black Hole Masses in Four Brightest Cluster Galaxies at 100 Mpc

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    We present stellar kinematics and orbit superposition models for the central regions of four Brightest Cluster Galaxies (BCGs), based upon integral-field spectroscopy at Gemini, Keck, and McDonald Observatories. Our integral-field data span radii from < 100 pc to tens of kpc. We report black hole masses, M_BH, of 2.1 +/- 1.6 x 10^10 M_Sun for NGC 4889, 9.7 + 3.0 - 2.6 x 10^9 M_Sun for NGC 3842, and 1.3 + 0.5 - 0.4 x 10^9 M_Sun for NGC 7768. For NGC 2832 we report an upper limit of M_BH < 9 x 10^9 M_Sun. Stellar orbits near the center of each galaxy are tangentially biased, on comparable spatial scales to the galaxies' photometric cores. We find possible photometric and kinematic evidence for an eccentric torus of stars in NGC 4889, with a radius of nearly 1 kpc. We compare our measurements of M_BH to the predicted black hole masses from various fits to the relations between M_BH and stellar velocity dispersion, luminosity, or stellar mass. The black holes in NGC 4889 and NGC 3842 are significantly more massive than all dispersion-based predictions and most luminosity-based predictions. The black hole in NGC 7768 is consistent with a broader range of predictions.Comment: 24 pages, 18 figures. Accepted for publication in Ap

    The anti-inflammatory effect of bacterial short chain fatty acids is partially mediated by endocannabinoids

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    The endocannabinoid (EC) system has pleiotropic functions in the body. It plays a key role in energy homeostasis and the development of metabolic disorders being a mediator in the relationship between the gut microbiota and host metabolism. In the current study we explore the functional interactions between the endocannabinoid system and the gut microbiome in modulating inflammatory markers. Using data from a 6week exercise intervention (treatment n =38 control n =40) and a cross sectional validation cohort (n=35), we measured the associations of 2-arachidonoylglycerol (2-AG), anandamide (AEA), N-oleoylethanolamine (OEA) and N-palmitoylethanolamine (PEA) with gut microbiome composition, gut derived metabolites (SCFAs) and inflammatory markers both cross-sectionally and longitudinally. At baseline AEA and OEA were positively associated with alpha diversity (β(SE)=.32 (.06), P =.002;.44 (.04), P <.001) and with SCFA producing bacteria such as Bifidobacterium (2-AG β(SE)=.21 (.10), P <.01; PEA β(SE)=.23 (.08), P <.01), Coprococcus 3 and Faecalibacterium (PEA β(SE)=.29 (.11), P =.01;.25 (.09), P <.01) and negatively associated with Collinsella (AEA β(SE)=−.31 (.12), P =.004). Additionally, we found AEA to be positively associated with SCFA Butyrate (β(SE)=.34 (.15), P =.01). AEA, OEA and PEA all increased significantly with the exercise intervention but remained constant in the control group. Changes in AEA correlated with SCFA butyrate and increases in AEA and PEA correlated with decreases in TNF-ɑ and IL-6 statistically mediating one third of the effect of SCFAs on these cytokines. Our data show that the anti-inflammatory effects of SCFAs are partly mediated by the EC system suggesting that there may be other pathways involved in the modulation of the immune system via the gut microbiome
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