Genomic imprinting in mouse blastocysts is predominantly associated with H3K27me3.

In mammalian genomes, differentially methylated regions (DMRs) and histone marks including trimethylation of histone 3 lysine 27 (H3K27me3) at imprinted genes are asymmetrically inherited to control parentally-biased gene expression. However, neither parent-of-origin-specific transcription nor imprints have been comprehensively mapped at the blastocyst stage of preimplantation development. Here, we address this by integrating transcriptomic and epigenomic approaches in mouse preimplantation embryos. We find that seventy-one genes exhibit previously unreported parent-of-origin-specific expression in blastocysts (nBiX: novel blastocyst-imprinted expressed). Uniparental expression of nBiX genes disappears soon after implantation. Micro-whole-genome bisulfite sequencing (µWGBS) of individual uniparental blastocysts detects 859 DMRs. We further find that 16% of nBiX genes are associated with a DMR, whereas most are associated with parentally-biased H3K27me3, suggesting a role for Polycomb-mediated imprinting in blastocysts. nBiX genes are clustered: five clusters contained at least one published imprinted gene, and five clusters exclusively contained nBiX genes. These data suggest that early development undergoes a complex program of stage-specific imprinting involving different tiers of regulation

Mental imagery and software visualization in high-performance software development teams

This paper considers the relationship between mental imagery and software visualization in professional, high-performance software development. It presents overviews of four empirical studies of professional software developers in high-performing teams: (1) expert programmers' mental imagery, (2) how experts externalize their mental imagery as part of teamwork, (3) experts' use of commercially available visualization software, and (4) what tools experts build themselves, how they use the tools they build for themselves, and why they build tools for themselves. Through this series of studies, the paper provides insight into a relationship between how experts reason about and imagine solutions, and their use of and requirements for external representations and software visualization. In particular, it provides insight into how experts use visualization in reasoning about software design, and how their requirements for the support of design tasks differ from those for the support of other software development tasks. The paper draws on theory from other disciplines to explicate issues in this area, and it discusses implications for future work in this field

Enzyme-linked immunofiltration assay used in the screening of solid supports and immunoreagents for the development of an azinphos-methyl flow immunosensor

Azinphos-methyl (AM), O,O-dimethyl S-[(4-oxo-1,2,3-benzotriazin-3(4H)-yl)methyl] phosphorodithioate, is a dithiophosphorous insecticide extensively used for the control of fruit culture pests. In this work the ELIFA system, initially developed and marketed to substitute conventional ELISA methods, was used for the screening of supports and immunoreagents in the development of a flow immunosensor to AM. The objective was to find the optimal antibody concentration, support quantity and enzymatic tracer concentration to develop a sensitive and reusable immunosensor. The influence of chitosan as protein stabilizing agent was also investigated. We observed that, on the basis of immunosorbent characterization, chitosan-modified silica with immobilized LIB-MFH14 monoclonal antibody (MAb) showed the best sensitivity, with a I50 value of 6 nM AM. All of the immobilized MAbs either in alkylaminated or chitosan-modified silica showed I50 values between 10 and 36 nM. Regarding the regeneration capability, the best desorption agent tested was 0.1 M glycine/HCl, pH 2.0, performing in most cases a 100% desorption after just one wash and maintaining the antibody activity even after 20 cycles of regeneration. The chitosan-modified silica seemed to be the best support for this purpose.http://www.sciencedirect.com/science/article/B6T2Y-44HWVKN-1/1/c9cc3be1ddfa14005d133d72353dd8e

Deliberate practice enhances quality of laparoscopic surgical performance in a randomized controlled trial: from arrested development to expert performance

BACKGROUND: This study investigated whether deliberate practice leads to an increase in surgical quality in virtual reality (VR) laparoscopic cholecystectomies (LC). Previous research has suggested that sustained DP is effective in surgical training. METHODS: Fourteen residents were randomized into deliberate practice (n=7) or control training (n=7). Both groups performed ten sessions of two VR LCs. Each session, the DP group was assigned 30min of DP activities in between LCs while the control group viewed educational videos or read journal articles. Performance was assessed on speed and dexterity; quality was rated with global (GRS) and procedure-specific (PSRS) rating scales. All participants then performed five porcine LCs. RESULTS: Both groups improved over 20 VR LCs in time, dexterity, and global rating scales (all

Novel imprints in mouse blastocysts are predominantly DNA methylation independent

In mammals, chromatin marks at imprinted genes are asymmetrically inherited to control parentally-biased gene expression. This control is thought predominantly to involve parent-specific differentially methylated regions (DMR) in genomic DNA. However, neither parent-of-origin-specific transcription nor DMRs have been comprehensively mapped. We here address this by integrating transcriptomic and epigenomic approaches in mouse preimplantation embryos (blastocysts). Transcriptome-analysis identified 71 genes expressed with previously unknown parent-of-origin-specific expression in blastocysts (nBiX: novel blastocyst-imprinted expression). Uniparental expression of nBiX genes disappeared soon after implantation. Micro-whole-genome bisulfite sequencing (μWGBS) of individual uniparental blastocysts detected 859 DMRs. Only 18% of nBiXs were associated with a DMR, whereas 60% were associated with parentally-biased H3K27me3. This suggests a major role for Polycomb-mediated imprinting in blastocysts. Five nBiX-clusters contained at least one known imprinted gene, and five novel clusters contained exclusively nBiX-genes. These data suggest a complex program of stage-specific imprinting involving different tiers of regulation

Genomic imprinting in mouse blastocysts is predominantly associated with H3K27me3

Abstract: In mammalian genomes, differentially methylated regions (DMRs) and histone marks including trimethylation of histone 3 lysine 27 (H3K27me3) at imprinted genes are asymmetrically inherited to control parentally-biased gene expression. However, neither parent-of-origin-specific transcription nor imprints have been comprehensively mapped at the blastocyst stage of preimplantation development. Here, we address this by integrating transcriptomic and epigenomic approaches in mouse preimplantation embryos. We find that seventy-one genes exhibit previously unreported parent-of-origin-specific expression in blastocysts (nBiX: novel blastocyst-imprinted expressed). Uniparental expression of nBiX genes disappears soon after implantation. Micro-whole-genome bisulfite sequencing (µWGBS) of individual uniparental blastocysts detects 859 DMRs. We further find that 16% of nBiX genes are associated with a DMR, whereas most are associated with parentally-biased H3K27me3, suggesting a role for Polycomb-mediated imprinting in blastocysts. nBiX genes are clustered: five clusters contained at least one published imprinted gene, and five clusters exclusively contained nBiX genes. These data suggest that early development undergoes a complex program of stage-specific imprinting involving different tiers of regulation