866 research outputs found
Protein crystals in adenovirus type 5-infected cells: requirements for intranuclear crystallogenesis, structural and functional analysis
Intranuclear crystalline inclusions have been observed in the nucleus of epithelial cells infected with Adenovirus serotype 5 (Ad5) at late steps of the virus life cycle. Using immuno-electron microscopy and confocal microscopy of cells infected with various Ad5 recombinants modified in their penton base or fiber domains, we found that these inclusions represented crystals of penton capsomers, the heteromeric capsid protein formed of penton base and fiber subunits. The occurrence of protein crystals within the nucleus of infected cells required the integrity of the fiber knob and part of the shaft domain. In the knob domain, the region overlapping residues 489–492 in the FG loop was found to be essential for crystal formation. In the shaft, a large deletion of repeats 4 to 16 had no detrimental effect on crystal inclusions, whereas deletion of repeats 8 to 21 abolished crystal formation without altering the level of fiber protein expression. This suggested a crucial role of the five penultimate repeats in the crystallisation process. Chimeric pentons made of Ad5 penton base and fiber domains from different serotypes were analyzed with respect to crystal formation. No crystal was found when fiber consisted of shaft (S) from Ad5 and knob (K) from Ad3 (heterotypic S5-K3 fiber), but occurred with homotypic S3K3 fiber. However, less regular crystals were observed with homotypic S35-K35 fiber. TB5, a monoclonal antibody directed against the Ad5 fiber knob was found by immunofluorescence microscopy to react with high efficiency with the intranuclear protein crystals in situ. Data obtained with Ad fiber mutants indicated that the absence of crystalline inclusions correlated with a lower infectivity and/or lower yields of virus progeny, suggesting that the protein crystals might be involved in virion assembly. Thus, we propose that TB5 staining of Ad-infected 293 cells can be used as a prognostic assay for the viability and productivity of fiber-modified Ad5 vectors
How important is the context of an adolescent's first alcoholic drink? Evidence that parental provision may reduce later heavy episodic drinking
Objective: This study examined the extent to which a retrospective measure of parental provision of the first alcoholic beverage was related to current heavy episodic drinking and current responsible drinking practices. Sample: 608 14- to 17-year-olds from the 2007 Australian National Drug Strategy Household Survey. Measures: Source of first alcoholic beverage (friends/parents/others), source of current alcohol, age of onset of alcohol use, current responsible drinking practices, and proportion of current friends who drink. Results: Binary logistic and multiple regression procedures revealed that parental provision of an adolescent's first alcoholic beverage predicted lower current heavy episodic drinking, and responsible drinking mediated this association. Discussion: The results suggested that for adolescents who become alcohol users, parental provision of the first drink may reduce subsequent alcohol-related risks compared to introduction to alcohol by friends and other sources. Alcohol-related risks remain significant for adolescents who consume alcohol, independent of who is the provider. Copyright (C) 2012 S. Karger AG, Base
Does managerial ability and auditor report readability affect corporate liquidity and cost of debt?
Purpose: This study investigates the impact of managerial ability and auditor report readability on the cost of debt and corporate liquidity in Omani-listed industrial companies.
Design/methodology/approach: The study uses data from the S&P Capital IQ database and audited annual reports published on Muscat Securities Market. The sample consists of 35 firms (175 firm-year observations) from 2015 to 2019. Managerial ability is measured using the data envelopment analysis proposed by Demerjian et al. (2012a, b). Auditor report readability is measured as a log of the auditor report digital file size proposed by Loughran and McDonald (2014).
Findings: This study finds that a company's managerial ability reduces the cost of debt lending support to upper echelons and agency theory. Highly able managers of industrial companies are associated with increased corporate liquidity consistent with the precautionary motive of holding cash. In addition, less-readable auditor reports contribute to higher debt costs and reduce corporate liquidity.
Originality/value: To the best of the authors’ knowledge, few studies have explored the influence of managerial ability and auditor reporting readability on firms' financial policy. For industrial-sector firms, this study demonstrates the managerial ability and readability of auditor readability as significant determinants of the cost of debt and corporate liquidity, especially during periods of uncertainty. Thus, the findings can be generalized to other non-financial sector firms in the country and the Middle East
Do intellectual capital efficiency and institutional quality influence a firm’s capital structure? Evidence from India
Purpose: This research explores the influence of intellectual capital (IC) efficiency (ICE) and institutional quality (IQ) on a firm’s capital structure (CS) in Indian firms.
Design/methodology/approach: The analysis was conducted on a sample of Indian companies from 2015 to 2019. Data were collected from the S&P database, and regression and additional analyses were performed to achieve the objectives of this research.
Findings: The findings show a significant positive effect of ICE on a firm’s CS from debt (CSD) and an insignificant positive effect of IQ on CSD and CS from equity (CSE). The findings also indicate that human-capital efficiency (HCE) and capital-employed efficiency (CEE) are the main IC sub-dimensions influencing a firm’s CS, compared to the structural-capital efficiency (SCE) dimension.
Practical implications: The results of this study have several practical implications, as they examine the influence of ICE and IQ on CS as potential determinants, which could help business leaders adopt optimal CS strategies.
Originality/value: The results of this study offer several novel contributions to the existing literature on CS by examining unexplored factors, such as ICE as a knowledge management strategy, ICE sub-dimensions, and IQ in the context of CS
Optimization of machining parameters and wire vibration in wire electrical discharge machining process
Search for new physics in the multijet and missing transverse momentum final state in proton-proton collisions at √s=8 Tev
Peer reviewe
Measurement of Higgs boson production and properties in the WW decay channel with leptonic final states
Peer reviewe
Generation of peptide-specific cytotoxic T cells and presence of regulatory T cells during vaccination with hTERT (class I and II) peptide-pulsed DCs
Optimal techniques for DC generation for immunotherapy in cancer are yet to be established. Study aims were to evaluate: (i) DC activation/maturation milieu (TNF-α +/- IFN-α) and its effects on CD8+ hTERT-specific T cell responses to class I epitopes (p540 or p865), (ii) CD8+ hTERT-specific T cell responses elicited by vaccination with class I alone or both class I and II epitope (p766 and p672)-pulsed DCs, prepared without IFN-α, (iii) association between circulating T regulatory cells (Tregs) and clinical responses
Current opinion on the role of testosterone in the development of prostate cancer: a dynamic model
Background: Since the landmark study conducted by Huggins and Hodges in 1941, a failure to distinguish between the role of testosterone in prostate cancer development and progression has led to the prevailing opinion that high levels of testosterone increase the risk of prostate cancer. To date, this claim remains unproven.
Presentation of the Hypothesis: We present a novel dynamic mode of the relationship between testosterone and prostate cancer by hypothesizing that the magnitude of age-related declines in testosterone, rather than a static level of testosterone measured at a single point, may trigger and promote the development of prostate cancer.
Testing of the Hypothesis: Although not easily testable currently, prospective cohort studies with population-representative samples and repeated measurements of testosterone or retrospective cohorts with stored blood samples from different ages are warranted in future to test the hypothesis.
Implications of the Hypothesis: Our dynamic model can satisfactorily explain the observed age patterns of prostate cancer incidence, the apparent conflicts in epidemiological findings on testosterone and risk of prostate cancer, racial disparities in prostate cancer incidence, risk factors associated with prostate cancer, and the role of testosterone in prostate cancer progression. Our dynamic model may also have implications for testosterone replacement therapy
Histone deacetylases suppress cgg repeat-induced neurodegeneration via transcriptional silencing in models of Fragile X Tremor Ataxia Syndrome
Fragile X Tremor Ataxia Syndrome (FXTAS) is a common inherited neurodegenerative disorder caused by expansion of a CGG trinucleotide repeat in the 59UTR of the fragile X syndrome (FXS) gene, FMR1. The expanded CGG repeat is thought to induce toxicity as RNA, and in FXTAS patients mRNA levels for FMR1 are markedly increased. Despite the critical role of FMR1 mRNA in disease pathogenesis, the basis for the increase in FMR1 mRNA expression is unknown. Here we show that overexpressing any of three histone deacetylases (HDACs 3, 6, or 11) suppresses CGG repeat-induced neurodegeneration in a Drosophila model of FXTAS. This suppression results from selective transcriptional repression of the CGG repeat-containing transgene. These findings led us to evaluate the acetylation state of histones at the human FMR1 locus. In patient-derived lymphoblasts and fibroblasts, we determined by chromatin immunoprecipitation that there is increased acetylation of histones at the FMR1 locus in pre-mutation carriers compared to control or FXS derived cell lines. These epigenetic changes correlate with elevated FMR1 mRNA expression in pre-mutation cell lines. Consistent with this finding, histone acetyltransferase (HAT) inhibitors repress FMR1 mRNA expression to control levels in pre-mutation carrier cell lines and extend lifespan in CGG repeat-expressing Drosophila. These findings support a disease model whereby the CGG repeat expansion in FXTAS promotes chromatin remodeling in cis, which in turn increases expression of the toxic FMR1 mRNA. Moreover, these results provide proof of principle that HAT inhibitors or HDAC activators might be used to selectively repress transcription at the FMR1 locus.open293
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