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Journal articlePallett MA, Berger CN, Pearson JS, et al., 2014, , INFECTION AND IMMUNITY, Vol: 82, Pages: 4878-4888, ISSN: 0019-9567
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- Citations: 25
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Journal articleClements A, Stoneham CA, Furniss RCD, et al., 2014, , CELLULAR MICROBIOLOGY, Vol: 16, Pages: 1693-1705, ISSN: 1462-5814
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- Citations: 12
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Journal articleFajardo A, Hernando-Amado S, Oliver A, et al., 2014, , JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY, Vol: 69, Pages: 2972-2978, ISSN: 0305-7453
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- Citations: 30
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Journal articleKrynicka V, Tichy M, Krafl J, et al., 2014, , MOLECULAR MICROBIOLOGY, Vol: 94, Pages: 609-624, ISSN: 0950-382X
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- Citations: 38
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Journal articleLeung HTA, Kukic P, Camilloni C, et al., 2014, , PROTEIN SCIENCE, Vol: 23, Pages: 1596-1606, ISSN: 0961-8368
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- Citations: 7
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Journal articleBryan SJ, Burroughs NJ, Shevela D, et al., 2014, , Molecular Microbiology, Vol: 94, Pages: 1179-1195, ISSN: 1365-2958
The Vipp1 protein is essential in cyanobacteria andchloroplasts for the maintenance of photosyntheticfunction and thylakoid membrane architecture. Toinvestigate its mode of action we generated strainsof the cyanobacteria Synechocystis sp. PCC6803and Synechococcus sp. PCC7942 in which Vipp1was tagged with green fluorescent protein at theC-terminus and expressed from the native chromosomallocus. There was little perturbation of function. Live-cell fluorescence imaging shows dramatic relocalisationof Vipp1 under high light. Under low light,Vipp1 is predominantly dispersed in the cytoplasmwith occasional concentrations at the outer peripheryof the thylakoid membranes. High light induces Vipp1coalescence into localised puncta within minutes, withnet relocation of Vipp1 to the vicinity of the cytoplasmicmembrane and the thylakoid membranes. Pulldownsand mass spectrometry identify an extensivecollection of proteins that are directly or indirectlyassociated with Vipp1 only after high-light exposure.These include not only photosynthetic and stressrelatedproteins but also RNA-processing, translationand protein assembly factors. This suggests that theVipp1 puncta could be involved in protein assembly.One possibility is that Vipp1 is involved in the formationof stress-induced localised protein assemblycentres, enabling enhanced protein synthesis anddelivery to membranes under stress conditions.
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Journal articleHohenester E, Yurchenco PD, 2013, , CELL ADHESION & MIGRATION, Vol: 7, Pages: 56-63
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- Citations: 334
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Journal articleLee C, Kang HJ, Hjelm A, et al., 2014, , FEBS LETTERS, Vol: 588, Pages: 3761-3769, ISSN: 0014-5793
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- Citations: 24
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Journal articleBurroughs NJ, Boehm M, Eckert C, et al., 2014, , Energy Environ Sci, Vol: 7, Pages: 3791-3800, ISSN: 1754-5692
Cyanobacteria contain a bidirectional [NiFe] hydrogenase which transiently produces hydrogen upon exposure of anoxic cells to light, potentially acting as a "valve" releasing excess electrons from the electron transport chain. However, its interaction with the photosynthetic electron transport chain remains unclear. By GFP-tagging the HoxF diaphorase subunit we show that the hydrogenase is thylakoid associated, comprising a population dispersed uniformly through the thylakoids and a subpopulation localized to discrete puncta in the distal thylakoid. Thylakoid localisation of both the HoxH and HoxY hydrogenase subunits is confirmed by immunogold electron microscopy. The diaphorase HoxE subunit is essential for recruitment to the dispersed thylakoid population, potentially anchoring the hydrogenase to the membrane, but aggregation to puncta occurs through a distinct HoxE-independent mechanism. Membrane association does not require NDH-1. Localization is dynamic on a scale of minutes, with anoxia and high light inducing a significant redistribution between these populations in favour of puncta. Since HoxE is essential for access to its electron donor, electron supply to the hydrogenase depends on a physiologically controlled localization, potentially offering a new avenue to enhance photosynthetic hydrogen production by exploiting localization/aggregation signals.
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Journal articleCampeotto I, Percy MG, MacDonald JT, et al., 2014, , Journal of Biological Chemistry, Vol: 289, Pages: 28054-28069, ISSN: 0021-9258
Lipoteichoic acid (LTA) is an important cell wall componentrequired for proper cell growth in many Gram-positive bacteria.In Listeria monocytogenes, two enzymes are required for the synthesisof this polyglycerolphosphate polymer. The LTA primaseLtaPLm initiates LTA synthesis by transferring the first glycerolphosphate(GroP) subunit onto the glycolipid anchor and theLTA synthase LtaSLm extends the polymer by the repeated additionof GroP subunits to the tip of the growing chain. Here, wepresent the crystal structures of the enzymatic domains ofLtaPLm and LtaSLm. Although the enzymes share the same fold,substantial differences in the cavity of the catalytic site andsurface charge distribution contribute to enzyme specialization.The eLtaSLm structure was also determined in complexwith GroP revealing a second GroP binding site. Mutationalanalysis confirmed an essential function for this binding siteand allowed us to propose a model for the binding of thegrowing chain.
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Journal articleBoulet-Audet M, Byrne B, Kazarian SG, 2014, , Analytical Chemistry, Vol: 86, Pages: 9786-9793, ISSN: 0003-2700
The use of biotherapeutics, such as monoclonal antibodies, has markedly increased in recent years. It is thus essential that biotherapeutic production pipelines are as efficient as possible. For the production process, one of the major concerns is the propensity of a biotherapeutic antibody to aggregate. In addition to reducing bioactive material recovery, protein aggregation can have major effects on drug potency and cause highly undesirable immunological effects. It is thus essential to identify processing conditions which maximize recovery while avoiding aggregation. Heat resistance is a proxy for long-term aggregation propensity. Thermal stability assays are routinely performed using various spectroscopic and scattering detection methods. Here, we evaluated the potential of macro attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopic imaging as a novel method for the high-throughput thermal stability assay of a monoclonal antibody. This chemically specific visualization method has the distinct advantage of being able to discriminate between monomeric and aggregated protein. Attenuated total reflection is particularly suitable for selectively probing the bottom of vessels, where precipitated aggregates accumulate. With focal plane array detection, we tested 12 different buffer conditions simultaneously to assess the effect of pH and ionic strength on protein thermal stability. Applying the Finke model to our imaging kinetics allowed us to determine the rate constants of nucleation and autocatalytic growth. This analysis demonstrated the greater stability of our immunoglobulin at higher pH and moderate ionic strength, revealing the key role of electrostatic interactions. The high-throughput approach presented here has significant potential for analyzing the stability of biotherapeutics as well as any other biological molecules prone to aggregation.
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Journal articleCollins JW, Chervaux C, Raymond B, et al., 2014, , JOURNAL OF INFECTIOUS DISEASES, Vol: 210, Pages: 1029-1041, ISSN: 0022-1899
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- Citations: 29
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Journal articleDevi S, Williams DR, 2014, , EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS, Vol: 88, Pages: 492-501, ISSN: 0939-6411
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- Citations: 14
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Journal articleHingorani K, Pace R, Whitney S, et al., 2014, , BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS, Vol: 1837, Pages: 1821-1834, ISSN: 0005-2728
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- Citations: 13
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Journal articleMichoux F, Boehm M, Bialek W, et al., 2014, , PHOTOSYNTHESIS RESEARCH, Vol: 122, Pages: 57-67, ISSN: 0166-8595
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- Citations: 25
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Journal articleDouse CH, Maas SJ, Thomas JC, et al., 2014, , ACS CHEMICAL BIOLOGY, Vol: 9, Pages: 2204-2209, ISSN: 1554-8929
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- Citations: 46
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Journal articleMoscoso JA, Jaeger T, Valentini M, et al., 2014, , Journal of Bacteriology, Vol: 196, Pages: 4081-4088, ISSN: 1098-5530
Pseudomonas aeruginosa is a Gram-negative opportunistic human pathogen and a threat for immunocompromised and cysticfibrosis patients. It is responsible for acute and chronic infections and can switch between these lifestyles upon taking an informeddecision involving complex regulatory networks. The RetS/LadS/Gac/Rsm network and the cyclic-di-GMP (c-di-GMP)signaling pathways are both central to this phenomenon redirecting the P. aeruginosa population toward a biofilm mode ofgrowth, which is associated with chronic infections. While these two pathways were traditionally studied independently fromeach other, we recently showed that cellular levels of c-di-GMP are increased in the hyperbiofilm retS mutant. Here, we have formallyestablished the link between the two networks by showing that the SadC diguanylate cyclase is central to the Gac/Rsmassociatedphenotypes, notably, biofilm formation. Importantly, SadC is involved in the signaling that converges onto the RsmAtranslational repressor either via RetS/LadS or via HptB/HsbR. Although the level of expression of the sadC gene does not seemto be impacted by the regulatory cascade, the production of the SadC protein is tightly repressed by RsmA. This adds to thegrowing complexity of the signaling network associated with c-di-GMP in P. aeruginosa. While this organism possesses morethan 40 c-di-GMP-related enzymes, it remains unclear how signaling specificity is maintained within the c-di-GMP network. Thefinding that SadC but no other diguanylate cyclase is related to the formation of biofilm governed by the Gac/Rsm pathway furthercontributes to understanding of this insulation mechanism.
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Journal articleMichie KA, Boysen A, Low HH, et al., 2014, , PLoS One, Vol: 9, Pages: 1-10, ISSN: 1932-6203
Escherichia coli (ETEC) strain H10407 contains a GTPase virulence factor, LeoA, which is encoded on a pathogenicity island and has been shown to enhance toxin release, potentially through vesicle secretion. By sequence comparisons and X-ray structure determination we now identify LeoA as a bacterial dynamin-like protein (DLP). Proteins of the dynamin family remodel membranes and were once thought to be restricted to eukaryotes. In ETEC H10407 LeoA localises to the periplasm where it forms a punctate localisation pattern. Bioinformatic analyses of leoA and the two upstream genes leoB and leoC suggest that LeoA works in concert with a second dynamin-like protein, made up of LeoB and LeoC. Disruption of the leoAB genes leads to a reduction in secretion of periplasmic Tat-GFP and outer membrane OmpA. Our data suggest a role for LeoABC dynamin-like proteins in potentiating virulence through membrane vesicle associated toxin secretion.
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Journal articleMatsuo E, Leon E, Matthews SJ, et al., 2014, , BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, Vol: 451, Pages: 603-608, ISSN: 0006-291X
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- Citations: 7
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Journal articleCole K, Buffler A, Cilliers JJ, et al., 2014, , Powder Technology, Vol: 263, Pages: 26-30, ISSN: 0032-5910
Positron emission particle tracking (PEPT) is a technique by which particle behaviour can be measured in a system of flow. The quality of the measurement is related to the spatial and temporal precision of the PET scanner and the characteristics of the tracer, which must replicate physical and chemical properties of the system bulk. Tracer particles can be made from ion exchange resins which have a high capacity for the commonly used positron emitting radionuclides 18F or 68Ga. However, these resins have a polymer composition and are naturally hydrophilic, which limits their application in systems involving mineral particles. This work presents a method to modify ion exchange resins with a coating to change the physical properties of the tracer. Two types of tracer were fabricated in this way, with hydrophobic and hydrophilic surfaces, to investigate the behaviour of valuable and gangue minerals in froth flotation with PEPT. The PEPT data were used to determine the spatial occupancies of each tracer, showing that the hydrophobic tracer has the highest occupancy in the froth region and the hydrophilic tracer is rarely entrained.
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Journal articleHirt MN, Boeddinghaus J, Mitchell A, et al., 2014, , JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY, Vol: 74, Pages: 151-161, ISSN: 0022-2828
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- Citations: 286
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Journal articleCollins JW, Keeney KM, Crepin VE, et al., 2014, , NATURE REVIEWS MICROBIOLOGY, Vol: 12, Pages: 612-623, ISSN: 1740-1526
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- Citations: 392
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Journal articleBerry AA, Yang Y, Pakharukova N, et al., 2014, , PLOS PATHOGENS, Vol: 10, ISSN: 1553-7366
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- Citations: 36
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Conference paperMota J, Holden DW, Domingues L, 2014,
The <i>Salmonella</i> effector SteA contributes to the control of membrane dynamics of <i>Salmonella</i>-containing vacuoles
, FEBS EMBO 2014 Conference, Publisher: WILEY-BLACKWELL, Pages: 766-767, ISSN: 1742-464X -
Journal articleMousnier A, Schroeder GN, Stoneham CA, et al., 2014, , MBIO, Vol: 5, ISSN: 2150-7511
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- Citations: 30
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Journal articleGründling A, 2014, , Microbe, Vol: 9, Pages: 315-320, ISSN: 1558-7452
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Journal articleChung L, Bailey D, Leen EN, et al., 2014, , Journal of Biological Chemistry, Vol: 289, Pages: 21738-21750, ISSN: 0021-9258
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Journal articleStevens MP, Frankel GM, 2014, , Microbiol Spectr, Vol: 2
A subset of Shiga toxin-producing Escherichia coli strains, termed enterohemorrhagic E. coli (EHEC), is defined in part by the ability to produce attaching and effacing (A/E) lesions on intestinal epithelia. Such lesions are characterized by intimate bacterial attachment to the apical surface of enterocytes, cytoskeletal rearrangements beneath adherent bacteria, and destruction of proximal microvilli. A/E lesion formation requires the locus of enterocyte effacement (LEE), which encodes a Type III secretion system that injects bacterial proteins into host cells. The translocated proteins, termed effectors, subvert a plethora of cellular pathways to the benefit of the pathogen, for example, by recruiting cytoskeletal proteins, disrupting epithelial barrier integrity, and interfering with the induction of inflammation, phagocytosis, and apoptosis. The LEE and selected effectors play pivotal roles in intestinal persistence and virulence of EHEC, and it is becoming clear that effectors may act in redundant, synergistic, and antagonistic ways during infection. Vaccines that target the function of the Type III secretion system limit colonization of reservoir hosts by EHEC and may thus aid control of zoonotic infections. Here we review the features and functions of the LEE-encoded Type III secretion system and associated effectors of E. coli O157:H7 and other Shiga toxin-producing E. coli strains.
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Journal articleCasini A, Christodoulou G, Freemont PS, et al., 2014, , ACS SYNTHETIC BIOLOGY, Vol: 3, Pages: 525-528, ISSN: 2161-5063
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- Citations: 49
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Journal articleXie H-X, Lu J-F, Rolhion N, et al., 2014, , INFECTION AND IMMUNITY, Vol: 82, Pages: 3436-3445, ISSN: 0019-9567
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- Citations: 40
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