2,238 research outputs found

    An emerging learning design for student-generated 'iVideos'

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    This paper describes an emerging learning design for a popular genre of learner-generated video projects: Ideas Videos or iVideos. These advocacy-style videos are short, two-minute, digital videos designed âto evoke powerful experiences about educative ideasâ (Wong, Mishra, Koehler & Siebenthal, 2007, p1). We draw on a recent study in teacher education to present a structured description of a pedagogical approach to iVideo filmmaking. A visual learning design representation (Agostinho, Harper, Oliver, Hedberg & Wills, 2008) and a LAMS-based generic learning design template (Cameron, 2008) form part of this description

    Manipulation of both virus- and cell-specific factors is required for robust transient replication of a hepatitis C virus genotype 3a sub-genomic replicon

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    Hepatitis C virus (HCV) genotype (GT) 3 is the second most prevalent of the seven HCV genotypes and exhibits the greatest resistance to the highly potent, direct-acting antivirals (DAAs) that are currently in use. Previously a stable cell line harbouring the S52 GT3 subgenomic replicon (SGR) was established, but this SGR was unable to robustly replicate transiently. As transient SGRs are a critical tool in the development of DAAs, and the study of viral resistance, we sought to establish a transient SGR system based on S52. Next generation sequencing was used to identify putative culture-adaptive substitutions that had arisen during long term selection of the S52 SGR. A subset of these substitutions were built back into the S52 SGR in the context of a CpG/UpA-low luciferase reporter, with a single point mutation in NS4A conferring the greatest replication capability upon S52. Modification of the innate immune-sensing pathways of Huh7.5 hepatoma cells by expression of the parainfluenza virus type 5 V protein and SEC14L2 resulted in a further enhancement of S52 replication. Furthermore, this transiently-replicating SGR showed genotype-specific differences in sensitivity to two clinically-relevant NS5A DAAs. In conclusion, we report that a single substitution in NS4A, coupled with host cell modifications, enabled robust levels of transient replication by the GT3 S52 SGR. This system will have beneficial uses in both basic research into the unique aspects of GT3 biology and drug discovery

    Is the ADP ribose site of the Chikungunya virus NSP3 Macro domain a target for antiviral approaches?

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    Chikungunya virus (CHIKV) is a mosquito-transmitted virus of special concern as it causes Chikungunya fever, characterized by an acute febrile illness, rash, and arthralgia that can progress to chronic and debilitating arthritic symptoms. The effects of climate change on the geographic distribution of the mosquito vector has the potential to expose more of the globe to this virus. No antiviral agents or vaccines are currently available against CHIKV infection and the development of novel therapies that may lead to a future treatment is therefore necessary. In this context, the ADP-ribose binding site of the CHIKV nsP3 macro domain has been reported as a potential target for the development of antivirals. Mutations in the ADP-ribose binding site demonstrated decreased viral replication in cell culture and reduced virulence. In this study, 48,750 small molecules were screened in silico for their ability to bind to the ADP-ribose binding site of the CHIKV nsP3 macro domain. From this in silico analysis, 12 molecules were selected for in vitro analysis using a CHIKV subgenomic replicon in Huh-7 cells. Cell viability and CHIKV replication were evaluated and molecules C5 and C13 demonstrated 53 and 66% inhibition of CHIKV replication, respectively. By using a CHIKV-Dual luciferase replicon contain two reporter genes, we also demonstrated that the treatment with either compounds are probably interfering in the early replication rather than after RNA replication has occurred

    Comprehensive analysis of type 1 fimbriae regulation in fimB -null strains from the multidrug resistant Escherichia coli ST131 clone

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    Summary\ud \ud Uropathogenic Escherichia coli (UPEC) of sequence type 131 (ST131) are a pandemic multidrug resistant clone associated with urinary tract and bloodstream infections. Type 1 fimbriae, a major UPEC virulence factor, are essential for ST131 bladder colonization. The globally dominant sub-lineage of ST131 strains, clade C/H30-R, possess an ISEc55 insertion in the fimB gene that controls phase-variable type 1 fimbriae expression via the invertible fimS promoter. We report that inactivation of fimB in these strains causes altered regulation of type 1 fimbriae expression. Using a novel read-mapping approach based on Illumina sequencing, we demonstrate that ‘off’ to ‘on’ fimS inversion is reduced in these strains and controlled by recombinases encoded by the fimE and fimX genes. Unlike typical UPEC strains, the nucleoid-associated H-NS protein does not strongly repress fimE transcription in clade C ST131 strains. Using a genetic screen to identify novel regulators of fimE and fimX in the clade C ST131 strain EC958, we defined a new role for the guaB gene in the regulation of type 1 fimbriae and in colonisation of the mouse bladder. Our results provide a comprehensive analysis of type 1 fimbriae regulation in ST131, and highlight important differences in its control compared to non-ST131 UPEC

    Cytotoxic polyfunctionality maturation of cytomegalovirus-pp65-specific CD4 + and CD8 + T-cell responses in older adults positively correlates with response size

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    Cytomegalovirus (CMV) infection is one of the most common persistent viral infections in humans worldwide and is epidemiologically associated with many adverse health consequences during aging. Previous studies yielded conflicting results regarding whether large, CMV-specific T-cell expansions maintain their function during human aging. In the current study, we examined the in vitro CMV-pp65-reactive T-cell response by comprehensively studying five effector functions (i.e., interleukin-2, tumor necrosis factor-α, interferon-γ, perforin, and CD107a expression) in 76 seropositive individuals aged 70 years or older. Two data-driven, polyfunctionality panels (IL-2-associated and cytotoxicity-associated) derived from effector function co-expression patterns were used to analyze the results. We found that, CMV-pp65-reactive CD8 + and CD4 + T cells contained similar polyfunctional subsets, and the level of polyfunctionality was related to the size of antigen-specific response. In both CD8 + and CD4 + cells, polyfunctional cells with high cytotoxic potential accounted for a larger proportion of the total response as the total response size increased. Notably, a higher serum CMV-IgG level was positively associated with a larger T-cell response size and a higher level of cytotoxic polyfunctionality. These findings indicate that CMV-pp65-specific CD4 + and CD8 + T cell undergo simultaneous cytotoxic polyfunctionality maturation during aging

    Oral Anti-Tumour Necrosis Factor Domain Antibody V565 Provides High Intestinal Concentrations, and Reduces Markers of Inflammation in Ulcerative Colitis Patients.

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    V565 is an engineered TNFα-neutralising single domain antibody formulated into enteric coated mini-tablets to enable release in the intestine after oral administration as a possible oral treatment for inflammatory bowel disease (IBD). Following oral administration, ileal recovery of V565 was investigated in four patients with terminal ileostomy. Intestinal and systemic pharmacokinetics were measured in six patients with Crohn's disease and evidence of target engagement assessed in five patients with ulcerative colitis. Following oral administration, V565 was detected at micromolar concentrations in ileal fluid from the ileostomy patients and in stools of the Crohn's patients. In four of the five ulcerative colitis patients, biopsies taken after 7d dosing demonstrated V565 in the lamina propria with co-immunostaining on CD3+ T-lymphocytes and CD14+ macrophages. Phosphorylation of signalling proteins in biopsies taken after 7d oral dosing was decreased by approximately 50%. In conclusion, enteric coating of V565 mini-tablets provided protection in the stomach with gradual release in intestinal regions affected by IBD. Immunostaining revealed V565 tissue penetration and association with inflammatory cells, while decreased phosphoproteins after 7d oral dosing was consistent with V565-TNFα engagement and neutralising activity. Overall these results are encouraging for the clinical utility of V565 in the treatment of IBD
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