Robert Orchard

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CRISPR-Cas9-based genetic screens are a powerful new tool in biology. By simply altering the sequence of the single-guide RNA (sgRNA), one can reprogram Cas9 to target different sites in the genome with relative ease, but the on-target activity and off-target effects of individual sgRNAs can vary widely. Here, we use recently devised sgRNA design rules to(More)
The Escherichia coli type III effector Map belongs to a large family of bacterial virulence factors that activate host Rho GTPase signaling pathways through an unknown molecular mechanism. Here we report direct evidence that Map functions as a potent and selective guanine-nucleotide exchange factor (GEF) for Cdc42. The 2.3-A structure of the Map-Cdc42(More)
LC3-associated phagocytosis (LAP) is a process wherein elements of autophagy conjugate LC3 to phagosomal membranes. We characterize the molecular requirements for LAP, and identify Rubicon as being required for LAP but not autophagy. Rubicon is recruited to LAPosomes and is required for the activity of a Class III PI(3)K complex containing UVRAG but lacking(More)
Jess, the JavaTM Expert System Shell, provides a rich and flexible environment for creating rule-based systems. Since it is written in Java it provides platform portability, extensibility and easy integration with other Java code or applications. The rules of Jess allow one to build systems that reason about knowledge that is expressed as facts. However,(More)
The fidelity and specificity of information flow within a cell is controlled by scaffolding proteins that assemble and link enzymes into signalling circuits. These circuits can be inhibited by bacterial effector proteins that post-translationally modify individual pathway components. However, there is emerging evidence that pathogens directly organize(More)
Small molecular weight GTPases are master regulators of eukaryotic signalling, making them prime targets for bacterial virulence factors. Here, we review the recent advances made in understanding how bacterial type III secreted effector proteins directly activate GTPase signalling cascades. Specifically we focus on the SopE/WxxxE family of effectors that(More)
This paper describes the Integrated Diagnostic System (IDS), an applied AI project concerned with the development of hybrid information systems to diagnose problems and help manage repair processes of commercial aircraft fleets. A study at one major airline indicated that significant benefits could accrue (approximately 2% of overall maintenance budget)(More)
The isolation and results of genomic and functional analyses of Rhodococcus equi phages ReqiPepy6, ReqiDocB7, ReqiPine5, and ReqiPoco6 (hereafter referred to as Pepy6, DocB7, Pine5, and Poco6, respectively) are reported. Two phages, Pepy6 and Poco6, more than 75% identical, exhibited genome organization and protein sequence likeness to Lactococcus lactis(More)
The effects of verapamil on the [K+]o rise produced by myocardial ischaemia were assessed in 26 open chest mongrel dogs. Ischaemia was produced by intermittent occlusion of the LAD artery (15 dogs) or by reduction of flow of the cannulated LAD (11 dogs). Specially constructed valinomycin K+ sensitive electrodes were inserted into the mid myocardium in the(More)
Defects in clearance of dying cells have been proposed to underlie the pathogenesis of systemic lupus erythematosus (SLE). Mice lacking molecules associated with dying cell clearance develop SLE-like disease, and phagocytes from patients with SLE often display defective clearance and increased inflammatory cytokine production when exposed to dying cells in(More)