:WYPUN 4LL[PUN 4HYJO¶ (WYPS ,KPUI\YNO 0U[LYUH[PVUHS *VUMLYLUJL *LU[YL (IZ[YHJ[Z Bacterial secretion systems: commonality and diversity 3 Plenary Session Influence of climate change on disease and microbial environmental processes: microbes and climate change 6 Hot Topic Symposium Type V secretion 8 Contents Cells & Cell Surfaces Group Biological basis of infection control 11 Clinical Microbiology Group How to pass the MRCPath Part 2: tips for the exam 14 Clinical Microbiology / Clinical Virology Groups Joint Session Workshop: Rapid diagnostics – ‘lab on a chip’ 15 Vaccines against viral infections from concept to practice 17 Clinical Virology Group Microbial metabolism of nitrogen-, phosphorus- and sulfur-containing compounds: environmental challenges, possible solutions and future perspectives 20 Environmental Microbiology Group Commercial industrial bioprocess development 24 Fermentation & Bioprocessing Group / IChemE BESG Transmission of viruses through the food chain 26 Food & Beverages Group The horizontal gene pool: the mobilome and virulence 28 Microbial Infection / Physiology, Biochemistry & Molecular Genetics Groups Joint Session Prokaryotic cell biology 31 Physiology, Biochemistry & Molecular Genetics Group Cyanobacteria, architects of our environment: who are they and what do they do? 34 Systematics & Evolution Group supported by the Environmental Microbiology Group Virus modulation of host defences 38 Control of virus gene expression 43 Virus Group Marjory Stephenson Prize Lecture 46 Fleming Prize Lecture 46 Posters 47 Authors 97 Late Abstracts 102 e Abstracts 76 Please note: Abstracts are printed as received from the authors and are not subjected to editing. Plenary Session Bacterial secretion systems: commonality and diversity Mechanism of ATP-driven translocation by the bacterial preprotein The YidC/Oxa1p/Alb3 family of proteins is a new class of proteins Plenary that play a role in the membrane assembly of proteins in bacteria, translocase mitochondria, and chloroplasts. In bacteria, null mutations in YidC are Arnold J.M. Driessen lethal, indicating that YidC is essential. YidC was discovered to be Dept of Molecular Microbiology, Groningen Biomolecular Sciences and critical for the membrane insertion of viral coat proteins that were Biotechnology Institute and the Zernike Institute for Advanced Materials, previously thought to insert into the membrane spontaneously. In University of Groningen, 9751 NN Haren, The Netherlands addition to acting as an independent insertase, YidC also assists in About 25–30% of the bacterial proteins function in the cell envelope membrane protein insertion in the Sec pathway. In this talk, we will or outside of the cell. These proteins are synthesized in the cytosol and highlight what is known about the role of the YidC insertase in the the vast majority is recognized as a ribosome-bound nascent chain by membrane insertion of subunit II of cytochrome bo3 oxidase. We will the signal recognition particle or by the secretion-dedicated chaperone also describe recent membrane insertion studies with Streptococcal SecB. Subsequently, they are targeted to the Sec-translocase in the mutans YidC family members and results of cold-sensitive mutants cytoplasmic membrane, a multimeric membrane protein complex with that indicate the importance of transmembrane segment 3 in YidC a highly conserved protein conducting channel, SecYEG, and function. peripheral bound ligands, the ribosome or the ATP-dependent motor protein SecA. The Sec-translocase mediates the translocation of Transport of folded proteins by the bacterial Tat (twin arginine proteins across the membrane and the insertion of membrane proteins translocation) pathway into the cytoplasmic membrane. Translocation requires the energy sources ATP and the proton motive force, while membrane protein Tracy Palmer insertion is coupled to polypeptide chain elongation at the ribosome. Division of Molecular & Environmental Microbiology, College of Life This presentation will discuss recent insights in the different structural Sciences, University of Dundee, Dundee DD1 5EH requirements for translocase-mediated membrane protein insertion The Tat protein translocase transports fully folded and often oligomeric and protein translocation. proteins across the bacterial cytoplasmic membrane and the thylakoid membrane of plant chloroplasts. Protein substrates are targeted to the The bacterial Sec translocase nanomotor: structure and function Tat machinery by N-terminal signal peptides that contain a twin T. Economou arginine motif. The Tat system of Escherichia coli comprises three University of Crete membrane-bound components, TatA, TatB and TatC. Under resting Abstract not received conditions the machinery comprises two separate, high molecular weight complexes. One complex is made up of TatB and TatC which The signal recognition particle targeting pathway in Escherichia coli acts as the receptor for substrates. Disulfide cross-linking expermients indicate that TatB is arranged as a multimeric unit, at least a tetramer, Harris D. Bernstein, Janine H. Peterson, Pu Tian & Cheryl A. Woolhead within the TatBC complex. The second type of complex contains only Genetics and Biochemistry Branch, National Institute of Diabetes and the TatA protein. This complex is highly heterogeneous and forms a Digestive and Kidney Diseases, National Institutes of Health, Bethesda ladder of bands on blue native PAGE, ranging from less than 100 to MD 20892, USA greater than 600 kD. Analysis of the TatA complex by negative stain The signal recognition particle (SRP) is a universally conserved electron microscopy and random conical tilt reconstruction reveals that ribonucleoprotein that recognizes signal sequences as they emerge it forms ring-shaped structures of variable diameter. These structures during translation and then targets ribosome-nascent chain complexes to the SecYEG/Sec61p translocation channel. Mammalian SRP enclose internal cavities which are large enough to accommodate recognizes both cleaved signal peptides and the transmembrane folded Tat substrate proteins, strongly suggesting that TatA forms the segments of integral membrane proteins, which function as internal protein conducting channel. The channel is closed by a lid, probably signal sequences. In contrast, we found that E. coli SRP recognizes located at the cytoplasmic side of the membrane, which may gate only transmembrane segments and a few cleaved signal peptides that substrate access. are exceptionally hydrophobic. Consequently, most proteins that contain cleaved signal peptides (periplasmic and outer membrane proteins) are targeted to the SecYEG channel post-translationally. In The ESX-1 secretion pathway in virulent mycobacteria recent studies we have examined the export of cytoplasmic proteins J. Cox fused to signal peptides. Previous work showed that cytoplasmic University of California at San Francisco, USA proteins must be targeted to the SecYEG channel co-translationally to prevent them from folding into a translocation-incompetent Abstract not received conformation. We found, however, that efficient export of several cytoplasmic proteins depends not only on the sequence of the signal Targeting proteins to the cell wall envelope of Gram-positive peptide, but also on the sequence of residues adjacent to the signal bacteria peptide. Our results indicate that the initiation of protein export involves a second event (presumably the opening of the SecYEG Olaf Schneewind channel) that is separable from the targeting reaction and that is Dept of Microbiology, University of Chicago, USA sensitive to sequences both within and just beyond the signal peptide. The cell wall envelopes of Gram-positive bacteria represent a surface organelle that not only functions as a cytoskeletal element but also Inserting and assembling proteins into bacterial membranes by the promotes interactions between bacteria and their environment. Cell YidC insertase wall peptidoglycan is covalently and noncovalently decorated with R. Dalbey teichoic acids, polysaccharides, and proteins. The sum of these Ohio State University, USA molecular decorations provides bacterial envelopes with species- and 3 strain-specific properties that are ultimately responsible for bacterial Outer membrane biogenesis in Gram-negative bacteria virulence, interactions with host immune systems, and the development Thomas J. Silhavy of disease symptoms or successful outcomes of infections. Surface Princeton University, USA proteins typically carry two topogenic sequences, i.e. N-terminal signal peptides and C-terminal sorting signals. Sortases catalyse a trans- The outer membrane (OM) of Gram-negative bacteria functions as a peptidation reaction by first cleaving a surface protein substrate at the protective barrier. It is unusual because the OM bilayer is asymmetric; cell wall sorting signal. The resulting acyl enzyme intermediates the inner leaflet is composed of phospholipids, but the outer leaflet is Plenary between sortases and their substrates are then resolved by the made of lipopolysaccharide (LPS). Two kinds of proteins are found in nucleophilic attack of amino groups, typically provided by the cell wall the OM. Lipoproteins are inserted into the inner leaflet of the OM by cross bridges of peptidoglycan precursors. Surface protein linked to posttranslationally attached lipid moieties. Integral OM proteins are β- peptidoglycan is then incorporated into the envelope and displayed on barrel proteins (OMPs). All of the components of the OM