The application of multiple-wavelength anomalous dispersion methods to protein crystallography

In order to collect crystallographic data rapidly and efficiently from proteins, an offline image plate detector was designed and installed on the beamline BM14, at the European Synchrotron Radiation Facility. The principal component of the detector was a rotating support frame onto which six image plates could be mounted. A barcode system identified each plate and differences in plate orientation were corrected by fiducial spots recorded using a xenon arc-lamp with fibre optic light guides. A suite of computer software was written to control the detector and manage all aspects of the data collection. [Continues.

Quantitative analysis of regulatory flexibility under changing environmental conditions

The circadian clock controls 24-h rhythms in many biological processes, allowing appropriate timing of biological rhythms relative to dawn and dusk. Known clock circuits include multiple, interlocked feedback loops. Theory suggested that multiple loops contribute the flexibility for molecular rhythms to track multiple phases of the external cycle. Clear dawn- and dusk-tracking rhythms illustrate the flexibility of timing in Ipomoea nil. Molecular clock components in Arabidopsis thaliana showed complex, photoperiod-dependent regulation, which was analysed by comparison with three contrasting models. A simple, quantitative measure, Dusk Sensitivity, was introduced to compare the behaviour of clock models with varying loop complexity. Evening-expressed clock genes showed photoperiod-dependent dusk sensitivity, as predicted by the three-loop model, whereas the one- and two-loop models tracked dawn and dusk, respectively. Output genes for starch degradation achieved dusk-tracking expression through light regulation, rather than a dusk-tracking rhythm. Model analysis predicted which biochemical processes could be manipulated to extend dusk tracking. Our results reveal how an operating principle of biological regulators applies specifically to the plant circadian clock

Crystallization and preliminary X-ray analysis of the 9 kDa protein of the mouse signal recognition particle and the selenomethionyl-SRP9

AbstractTwo different crystal forms of the 9 kDa protein of the signal recognition particle (SRP9) have been prepared by the hanging drop vapor diffusion technique using 28% (w/v) PEG8000 or 28% saturated ammonium sulphate as precipitant. The crystals are hexagonal bipyramids with average dimensions of 0.2 × 0.1 × 0.1 mm3 and they diffract to a resolution of 2.3 Å. They belong to the space groups P6222/P6422 or P3121/P3221 with cell dimensions a = b = 63.0 Å, and c = 111.5 Å. Crystals have also been grown from the selenomethionyl protein and multiwavelength data sets have been collected

Genetic effects on gene expression across human tissues

Characterization of the molecular function of the human genome and its variation across individuals is essential for identifying the cellular mechanisms that underlie human genetic traits and diseases. The Genotype-Tissue Expression (GTEx) project aims to characterize variation in gene expression levels across individuals and diverse tissues of the human body, many of which are not easily accessible. Here we describe genetic effects on gene expression levels across 44 human tissues. We find that local genetic variation affects gene expression levels for the majority of genes, and we further identify inter-chromosomal genetic effects for 93 genes and 112 loci. On the basis of the identified genetic effects, we characterize patterns of tissue specificity, compare local and distal effects, and evaluate the functional properties of the genetic effects. We also demonstrate that multi-tissue, multi-individual data can be used to identify genes and pathways affected by human disease-associated variation, enabling a mechanistic interpretation of gene regulation and the genetic basis of diseas

Genetic effects on gene expression across human tissues

Characterization of the molecular function of the human genome and its variation across individuals is essential for identifying the cellular mechanisms that underlie human genetic traits and diseases. The Genotype-Tissue Expression (GTEx) project aims to characterize variation in gene expression levels across individuals and diverse tissues of the human body, many of which are not easily accessible. Here we describe genetic effects on gene expression levels across 44 human tissues. We find that local genetic variation affects gene expression levels for the majority of genes, and we further identify inter-chromosomal genetic effects for 93 genes and 112 loci. On the basis of the identified genetic effects, we characterize patterns of tissue specificity, compare local and distal effects, and evaluate the functional properties of the genetic effects. We also demonstrate that multi-tissue, multi-individual data can be used to identify genes and pathways affected by human disease-associated variation, enabling a mechanistic interpretation of gene regulation and the genetic basis of disease

Play and Playfulness in Lynda Barry’s What It Is

This article discusses play and playfulness in Lynda Barry’s autobiographical comics/instructional work What It Is (2008). The term ‘playfulness’ is commonly used in two primary but distinct ways, namely in a phenomenological sense concerning a free attitude accompanying a given play activity, and referring to a frame-breaking form of disruption. I refer to the former as play/playing, and reserve the term ‘playfulness’ for the latter, while also suggesting that playfulness implies a form of disruptive attitude or intent. Playing is a central concept in Barry’s work, one on which the author draws in terms of formulating the creative process. Barry’s insistence on the phenomenological or experiential aspects of playing both reinforces and is reinforced by the stylistic aspects of What It Is. Thus, assertions of playfulness based on elements of Barry’s work that subvert convention, often via a form of ambiguity, are consistently countered by Barry’s emphasis on process. It is therefore argued that, if What It Is displays a form of playfulness, it is primarily in terms of the way that it occupies the border between immediacy and authenticity, on the one hand, and constructedness, on the other. The article first establishes the approach to playing adopted by Barry throughout What It Is, based on the work of D. W. Winnicott, and links it to other conceptualizations of play/playing, before drawing a distinction between playing and playfulness. Following this, it examines how Barry’s delineation of the creative process as play, as well as the author’s approach to style, achieves a perceived form of immediacy and authenticity. After this, following consideration of the playfulness of Barry’s collage pages, the article considers how What It Is occupies the border between immediacy and constructedness