193 research outputs found
Vacuum phototriodes for the CMS electromagnetic calorimeter endcap
The measurement of scintillation light from the lead tungstate crystals of the Compact Muon Solenoid (CMS) electromagnetic calorimeter (ECAL) poses a substantial technical challenge, particularly in the endcap regions, where the radiation levels are highest. The photodetectors must be fast, sensitive, radiationhard, and operate with significant internal gain in a magnetic field of 4 Tesla. The measured performance characteristics of the first batches of series production vacuum phototriodes (VPT), developed to satisfy the needs of CMS, will be described
In silico prediction of cancer immunogens:current state of the art
Cancer kills 8 million annually worldwide. Although survival rates in prevalent cancers continue to increase, many cancers have no effective treatment, prompting the search for new and improved protocols. Immunotherapy is a new and exciting addition to the anti-cancer arsenal. The successful and accurate identification of aberrant host proteins acting as antigens for vaccination and immunotherapy is a key aspiration for both experimental and computational research. Here we describe key elements of in silico prediction, including databases of cancer antigens and bleeding-edge methodology for their prediction. We also highlight the role dendritic cell vaccines can play and how they can act as delivery mechanisms for epitope ensemble vaccines. Immunoinformatics can help streamline the discovery and utility of Cancer Immunogens
New Noncovalent Inhibitors of Penicillin-Binding Proteins from Penicillin-Resistant Bacteria
BACKGROUND: Penicillin-binding proteins (PBPs) are well known and validated targets for antibacterial therapy. The most important clinically used inhibitors of PBPs beta-lactams inhibit transpeptidase activity of PBPs by forming a covalent penicilloyl-enzyme complex that blocks the normal transpeptidation reaction; this finally results in bacterial death. In some resistant bacteria the resistance is acquired by active-site distortion of PBPs, which lowers their acylation efficiency for beta-lactams. To address this problem we focused our attention to discovery of novel noncovalent inhibitors of PBPs. METHODOLOGY/PRINCIPAL FINDINGS: Our in-house bank of compounds was screened for inhibition of three PBPs from resistant bacteria: PBP2a from Methicillin-resistant Staphylococcus aureus (MRSA), PBP2x from Streptococcus pneumoniae strain 5204, and PBP5fm from Enterococcus faecium strain D63r. Initial hit inhibitor obtained by screening was then used as a starting point for computational similarity searching for structurally related compounds and several new noncovalent inhibitors were discovered. Two compounds had promising inhibitory activities of both PBP2a and PBP2x 5204, and good in-vitro antibacterial activities against a panel of Gram-positive bacterial strains. CONCLUSIONS: We found new noncovalent inhibitors of PBPs which represent important starting points for development of more potent inhibitors of PBPs that can target penicillin-resistant bacteria.Eur-Intafa
Network analysis of the Viking Age in Ireland as portrayed in Cogadh Gaedhel re Gallaibh
Cogadh Gaedhel re Gallaibh (‘The War of the Gaedhil with the Gaill’) is a medieval Irish text, telling how an army under the leadership of Brian Boru challenged Viking invaders and their allies in Ireland, culminating with the Battle of Clontarf in 1014. Brian’s victory is widely remembered for breaking Viking power in Ireland, although much modern scholarship disputes traditional perceptions. Instead of an international conflict between Irish and Viking, interpretations based on revisionist scholarship consider it a domestic feud or civil war. Counterrevisionists challenge this view and a long-standing and lively debate continues. Here, we introduce quantitative measures to the discussions.We present statistical analyses of network data embedded in the text to position its sets of interactions on a spectrum from the domestic to the international. This delivers a picture that lies between antipodal traditional and revisionist extremes; hostilities recorded in the text are mostly between Irish and Viking—but internal conflict forms a significant proportion of the negative interactions too
Inter-Species Complementation of the Translocon Beta Subunit Requires Only Its Transmembrane Domain
In eukaryotes, proteins enter the secretory pathway through the translocon pore of the endoplasmic reticulum. This protein translocation channel is composed of three major subunits, called Sec61α, β and γ in mammals. Unlike the other subunits, the β subunit is dispensable for translocation and cell viability in all organisms studied. Intriguingly, the knockout of the Sec61β encoding genes results in different phenotypes in different species. Nevertheless, the β subunit shows a high level of sequence homology across species, suggesting the conservation of a biological function that remains ill-defined. To address its cellular roles, we characterized the homolog of Sec61β in the fission yeast Schizosaccharomyces pombe (Sbh1p). Here, we show that the knockout of sbh1+ results in severe cold sensitivity, increased sensitivity to cell-wall stress, and reduced protein secretion at 23°C. Sec61β homologs from Saccharomyces cerevisiae and human complement the knockout of sbh1+ in S. pombe. As in S. cerevisiae, the transmembrane domain (TMD) of S. pombe Sec61β is sufficient to complement the phenotypes resulting from the knockout of the entire encoding gene. Remarkably, the TMD of Sec61β from S. cerevisiae and human also complement the gene knockouts in both yeasts. Together, these observations indicate that the TMD of Sec61β exerts a cellular function that is conserved across species
Molecular Dynamics Analysis of Apolipoprotein-D - Lipid Hydroperoxide Interactions: Mechanism for Selective Oxidation of Met-93
Background: Recent studies suggest reduction of radical-propagating fatty acid hydroperoxides to inert hydroxides by interaction with apolipoprotein-D (apoD) Met93 may represent an antioxidant function for apoD. The nature and structural consequences of this selective interaction are unknown.
Methodology/Principal Findings: Herein we used molecular dynamics (MD) analysis to address these issues. Longtimescale simulations of apoD suggest lipid molecules are bound flexibly, with the molecules free to explore multiple conformations in a binding site at the entrance to the classical lipocalin ligand-binding pocket. Models of 5s- 12s- and 15s hydroperoxyeicosatetraenoic acids were created and the lipids found to wrap around Met93 thus providing a plausible mechanism by which eicosatetraenoic acids bearing hydroperoxides on different carbon atoms can interact with Met93 to yield Met93 sulfoxide (Met93SO). Simulations of glycosylated apoD indicated that a second solvent exposed Met at position 49 was shielded by a triantennerary N-glycan attached to Asn45 thereby precluding lipid interactions. MD simulations of apoD showed B-factors of the loop containing Met93SO were higher in the oxidized protein, indicating increased flexibility that is predicted to destabilize the protein and promote self-association.
Conclusions/Significance: These studies provide novel insights into the mechanisms that may contribute to the antioxidant function of apoD and the structural consequences that result if Met93SO is not redox-cycled back to its native state
Physician practices related to use of BMI-for-age and counseling for childhood obesity prevention: A cross-sectional study
<p>Abstract</p> <p>Background</p> <p>Screening for obesity and providing appropriate obesity-related counseling in the clinical setting are important strategies to prevent and control childhood obesity. The purpose of this study is to document pediatricians (PEDs) and general practitioners (GPs) with pediatric patients use of BMI-for-age to screen for obesity, confidence in explaining BMI, access to referral clinics, and characteristics associated with screening and counseling to children and their caregivers.</p> <p>Methods</p> <p>The authors used 2008 DocStyles survey data to examine these practices at every well child visit for children aged two years and older. Counseling topics included: physical activity, TV viewing time, energy dense foods, fruits and vegetables, and sugar-sweetened beverages. Chi-square tests were used to examine differences in proportions and logistic regression to identify characteristics associated with screening and counseling.</p> <p>Results</p> <p>The final analytic sample included 250 PEDs and 621 GPs. Prevalence of using BMI-for-age to screen for obesity at every well child visit was higher for PEDs than GPs (50% vs. 22%, χ2 = 67.0, p ≤ 0.01); more PEDs reported being very/somewhat confident in explaining BMI (94% vs. GPs, 87%, p < 0.01); more PEDs reported access to a pediatric obesity specialty clinic for referral (PEDs = 65% vs. GPs = 42%, χ2 = 37.5, p ≤ 0.0001).</p> <p>In general, PEDs reported higher counseling prevalence than GPs. There were significant differences in the following topics: TV viewing (PEDs, 79% vs. GPs, 61%, χ2 = 19.1, p ≤ 0.0001); fruit and vegetable consumption (PEDs, 87% vs. GPs, 78%, χ2 = 6.4, p ≤ 0.01). The only characteristics associated with use of BMI for GPs were being female (OR = 2.3, 95% CI = 1.5-3.5) and serving mostly non-white patients (OR = 1.8, 95% CI = 1.1-2.9); there were no significant associations for PEDs.</p> <p>Conclusions</p> <p>The findings for use of BMI-for-age, counseling habits, and access to a pediatric obesity specialty clinic leave room for improvement. More research is needed to better understand why BMI-for-age is not being used to screen at every well child visit, which may increase the likelihood overweight and obese patients receive counseling and referrals for additional services. The authors also suggest more communication between PEDs and GPs through professional organizations to increase awareness of existing resources, and to enhance access and referral to pediatric obesity specialty clinics.</p
Inter-Species Complementation of the Translocon Beta Subunit Requires Only Its Transmembrane Domain
In eukaryotes, proteins enter the secretory pathway through the translocon pore of the endoplasmic reticulum. This protein translocation channel is composed of three major subunits, called Sec61α, β and γ in mammals. Unlike the other subunits, the β subunit is dispensable for translocation and cell viability in all organisms studied. Intriguingly, the knockout of the Sec61β encoding genes results in different phenotypes in different species. Nevertheless, the β subunit shows a high level of sequence homology across species, suggesting the conservation of a biological function that remains ill-defined. To address its cellular roles, we characterized the homolog of Sec61β in the fission yeast Schizosaccharomyces pombe (Sbh1p). Here, we show that the knockout of sbh1+ results in severe cold sensitivity, increased sensitivity to cell-wall stress, and reduced protein secretion at 23°C. Sec61β homologs from Saccharomyces cerevisiae and human complement the knockout of sbh1+ in S. pombe. As in S. cerevisiae, the transmembrane domain (TMD) of S. pombe Sec61β is sufficient to complement the phenotypes resulting from the knockout of the entire encoding gene. Remarkably, the TMD of Sec61β from S. cerevisiae and human also complement the gene knockouts in both yeasts. Together, these observations indicate that the TMD of Sec61β exerts a cellular function that is conserved across species
Re-Shuffling of Species with Climate Disruption: A No-Analog Future for California Birds?
By facilitating independent shifts in species' distributions, climate disruption may result in the rapid development of novel species assemblages that challenge the capacity of species to co-exist and adapt. We used a multivariate approach borrowed from paleoecology to quantify the potential change in California terrestrial breeding bird communities based on current and future species-distribution models for 60 focal species. Projections of future no-analog communities based on two climate models and two species-distribution-model algorithms indicate that by 2070 over half of California could be occupied by novel assemblages of bird species, implying the potential for dramatic community reshuffling and altered patterns of species interactions. The expected percentage of no-analog bird communities was dependent on the community scale examined, but consistent geographic patterns indicated several locations that are particularly likely to host novel bird communities in the future. These no-analog areas did not always coincide with areas of greatest projected species turnover. Efforts to conserve and manage biodiversity could be substantially improved by considering not just future changes in the distribution of individual species, but including the potential for unprecedented changes in community composition and unanticipated consequences of novel species assemblages
Apolipoprotein D synthesis progressively increases in frontal cortex during human lifespan
Apolipoprotein D (apo D) is a lipocalin present in the nervous system that may be related to processes of reinnervation, regeneration and neuronal cell protection. In the other way, apo D expression has been correlated, in some brain regions, with normal aging and neurodegenerative diseases. To elucidate the regional and cellular expression of apo D in normal human brain during aging, we performed a detailed and extensive study in samples of post-mortem human cerebral cortices. To achieve this study, slot blot techniques, for protein and mRNA, as well as immunohistochemistry and hybridohistochemistry methods were used. A positive correlation for apo D expression with aging was found; furthermore, mRNA levels, as well as the protein ones, were higher in the white than in the grey matter. Immunohistochemistry and non-isotopic HIS showed that apo D is synthesized in both neurons and glial cells. Apo D expression is notorious in oligodendrocytes but with aging the number of neurons that synthesize apo D is increased. Our results indicate that apo D could play a fundamental role in central nervous system aging and in the reduction of products derivated from lipid peroxidation. The increment in the expression of apo D with aging can be included in a global mechanism of cellular protection to prevent the deleterious effects caused by aging
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