Gad Frankel

Imperial College London, Londinium, England, United Kingdom

Are you Gad Frankel?

Claim your profile

Publications (172)873.7 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The enteric pathogens enteropathogenic Escherichia coli and enterohemorrhagic E. coli employ a T3SS to manipulate the host inflammatory response during infection. Previously, it has been reported that EPEC, in a T3SS-dependent manner, induces an early pro-inflammatory response through activation of NF-κB via ERK1/2 and PKCζ. However, no effector has yet been attributed to the activation of NF-κB during infection. At later time points post infection NF-κB signalling is inhibited through the translocation of multiple effectors including NleE and NleC. Here we report that the highly conserved non-LEE encoded effector F (NleF) shows both diffuse and mitochondrial localization during ectopic expression. Moreover, NleF induces nuclear translocation of NF-κB p65 and the expression of IL-8 following ectopic expression and during EPEC infection. Furthermore, the pro-inflammatory activity and localization of NleF was dependent on the C-terminal amino acids LQCG. Whilst the C-terminal domain of NleF was previously shown to be essential for interaction with caspase-4, -8 and -9; the pro-inflammatory activity of NleF was independent of caspase-4, -8 or -9 interaction. In conclusion EPEC, through the T3SS-dependent translocation of NleF, induces a pro-inflammatory response in an NF-κB dependent manner in the early stages of infection.
    Infection and immunity. 09/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Citrobacter rodentium is a mucosal pathogen of mice that shares several pathogenic mechanisms with enteropathogenic Escherichia coli (EPEC) and enterohaemorrhagic E. coli (EHEC), which are two clinically important human gastrointestinal pathogens. Thus, C. rodentium has long been used as a model to understand the molecular basis of EPEC and EHEC infection in vivo. In this Review, we discuss recent studies in which C. rodentium has been used to study mucosal immunology, including the deregulation of intestinal inflammatory responses during bacteria-induced colitis and the role of the intestinal microbiota in mediating resistance to colonization by enteric pathogens. These insights should help to elucidate the roles of mucosal inflammatory responses and the microbiota in the virulence of enteric pathogens.
    Nature Reviews Microbiology 08/2014; · 22.49 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC/EHEC) manipulate many cell processes by injecting effector proteins from the bacteria into the host cell via a Type III secretion system. In this paper we report that the effector protein EspG disrupts recycling endosome function. In particular, we found that following transferrin binding and endocytosis EspG reduces recycling of the transferrin receptor (TfR), the prototypical recycling protein, from an intracellular location to the cell surface, resulting in an accumulation of TfR within the cell. The surface levels of three receptors (TfR, Epidermal Growth Factor Receptor (EGFR) and β1 integrin) were tested and found to be reduced dependent on EspG translocation. Furthermore, disruption of recycling endosome function and the reduced surface presentation of receptors was dependent on the previously reported RabGAP activity and ARF binding ability of EspG. This paper therefore supports the previous hypothesis that EspG acts as an enzyme scaffold perturbing cell signalling events, in this case altering recycling endosome function and cell surface receptor levels during infection.
    Cellular Microbiology 06/2014; · 4.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We evaluated the protective effects of fermented dairy products (FDPs) in an infection model, using the mouse pathogen Citrobacter rodentium (CR). Treatment of mice with FDP formulas A, B, C or a control product did not affect CR colonization, organ specificity, or attaching and effacing lesion formation. Fermented dairy product A (FDP-A), but neither the supernatant from FDP-A nor β-irradiated (IR)-FDP-A, caused a significant reduction in colonic crypt hyperplasia and CR-associated pathology. Profiling the gut microbiota revealed that IR-FDP-A promoted higher levels of phylotypes belonging to Alcaligenaceae and a decrease in Lachnospiraceae (Ruminococcus) during CR infection. Conversely, FDP-A prevented a decrease in Ruminococcus and increased Turicibacteraceae (Turicibacter). Importantly, loss of Ruminococcus and Turicibacter has been associated with susceptibility to dextran sodium sulfate-induced colitis. Our results demonstrate that viable bacteria in FDP-A reduced CR-induced colonic crypt hyperplasia and prevented the loss of key bacterial genera that may contribute to disease pathology.
    The Journal of Infectious Diseases 04/2014; · 5.85 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Mucus production by goblet cells of the large intestine serves as a crucial antimicrobial protective mechanism at the interface between the eukaryotic and prokaryotic cells of the mammalian intestinal ecosystem. However, the regulatory pathways involved in goblet cell-induced mucus secretion remain largely unknown. Here, we demonstrate that the NLRP6 inflammasome, a recently described regulator of colonic microbiota composition and biogeographical distribution, is a critical orchestrator of goblet cell mucin granule exocytosis. NLRP6 deficiency leads to defective autophagy in goblet cells and abrogated mucus secretion into the large intestinal lumen. Consequently, NLRP6 inflammasome-deficient mice are unable to clear enteric pathogens from the mucosal surface, rendering them highly susceptible to persistent infection. This study identifies an innate immune regulatory pathway governing goblet cell mucus secretion, linking nonhematopoietic inflammasome signaling to autophagy and highlighting the goblet cell as a critical innate immune player in the control of intestinal host-microbial mutualism. PAPERCLIP:
    Cell 02/2014; 156(5):1045-59. · 31.96 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Legionella pneumophila, the causative agent of Legionnaires' disease, uses the Dot/Icm type IV secretion system (T4SS) to translocate more than 300 effectors into host cells, where they subvert host cell signaling. The function and host cell targets of most effectors remain unknown. PieE is a 69-kDa Dot/Icm effector containing three coiled-coil (CC) regions and 2 transmembrane (TM) helices followed by a fourth CC region. Here, we report that PieE dimerized by an interaction between CC3 and CC4. We found that ectopically expressed PieE localized to the endoplasmic reticulum (ER) and induced the formation of organized smooth ER, while following infection PieE localized to the Legionella-containing vacuole (LCV). To identify the physiological targets of PieE during infection, we established a new purification method for which we created an A549 cell line stably expressing the Escherichia coli biotin ligase BirA and infected the cells with L. pneumophila expressing PieE fused to a BirA-specific biotinylation site and a hexahistidine tag. Following tandem Ni(2+) nitrilotriacetic acid (NTA) and streptavidin affinity chromatography, the effector-target complexes were analyzed by mass spectrometry. This revealed interactions of PieE with multiple host cell proteins, including the Rab GTPases 1a, 1b, 2a, 5c, 6a, 7, and 10. Binding of the Rab GTPases, which was validated by yeast two-hybrid binding assays, was mediated by the PieE CC1 and CC2. In summary, using a novel, highly specific strategy to purify effector complexes from infected cells, which is widely applicable to other pathogens, we identified PieE as a multidomain LCV protein with promiscuous Rab GTPase-binding capacity.
    mBio 01/2014; 5(4). · 6.88 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Successful infection by enteric bacterial pathogens depends on the ability of the bacteria to colonize the gut, replicate in host tissues and disseminate to other hosts. Pathogens such as Salmonella, Shigella and enteropathogenic and enterohaemorrhagic (EPEC and EHEC, respectively) Escherichia coli use a type III secretion system (T3SS) to deliver virulence effector proteins into host cells during infection that promote colonization and interfere with antimicrobial host responses. Here we report that the T3SS effector NleB1 from EPEC binds to host cell death-domain-containing proteins and thereby inhibits death receptor signalling. Protein interaction studies identified FADD, TRADD and RIPK1 as binding partners of NleB1. NleB1 expressed ectopically or injected by the bacterial T3SS prevented Fas ligand or TNF-induced formation of the canonical death-inducing signalling complex (DISC) and proteolytic activation of caspase-8, an essential step in death-receptor-induced apoptosis. This inhibition depended on the N-acetylglucosamine transferase activity of NleB1, which specifically modified Arg 117 in the death domain of FADD. The importance of the death receptor apoptotic pathway to host defence was demonstrated using mice deficient in the FAS signalling pathway, which showed delayed clearance of the EPEC-like mouse pathogen Citrobacter rodentium and reversion to virulence of an nleB mutant. The activity of NleB suggests that EPEC and other attaching and effacing pathogens antagonize death-receptor-induced apoptosis of infected cells, thereby blocking a major antimicrobial host response.
    Nature 09/2013; 501(7466):247-51. · 38.60 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The Dot/Icm type IV secretion system (T4SS) of Legionella pneumophila is crucial for the pathogen to survive in protozoa and cause human disease. Although more than 275 effector proteins are delivered into the host cell by the T4SS, the function of the majority is unknown. Here we have characterized the Dot/Icm effector LtpD. During infection LtpD localized to the cytoplasmic face of the membrane of the Legionella containing vacuole (LCV). In A549 lung epithelial cells, ectopically-expressed LtpD localized to large vesicular structures which contained markers of endosomal compartments. Systematic analysis of LtpD fragments identified an internal 17 kDa fragment, LtpD471-626, which was essential for targeting ectopically-expressed LtpD to vesicular structures and for association of translocated LtpD with the LCV. LtpD471-626 bound directly to phosphatidylinositol-3-phosphate (PtdIns (3)P) in vitro and co-localized with the PtdIns (3)P markers FYVE and SetA in co-transfected cells. LtpD was also found to bind the host cell enzyme inositol (myo)-1 (or 4)-monophosphatase 1, an important phosphatase involved in phosphoinositide production. Analysis of the role of LtpD in infection showed that LtpD is involved in bacterial replication in THP-1 macrophages, the larvae of Galleria mellonella and mouse lungs. Together, these data suggest that LtpD is a novel phosphoinositide-binding L. pneumophila effector, which has a role in intracellular bacterial replication.
    Infection and immunity 09/2013; · 4.21 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Enteropathogenic and enterohaemorrhagic Escherichia coli use a novel infection strategy to colonize the gut epithelium, involving translocation of their own receptor, Tir, via a type III secretion system and subsequent formation of attaching and effecting (A/E) lesions. Following integration into the host cell plasma membrane of cultured cells, and clustering by the outer membrane adhesin intimin, Tir triggers multiple actin polymerization pathways involving host and bacterial adaptor proteins that converge on the host Arp2/3 actin nucleator. Although initially thought to be involved in A/E lesion formation, recent data have shown that the known Tir-induced actin polymerization pathways are dispensable for this activity, but can play other major roles in colonization efficiency, in vivo fitness and systemic disease. In this review we summarize the roadmap leading from the discovery of Tir, through the different actin polymerization pathways it triggers, to our current understanding of their physiological functions.
    Cellular Microbiology 08/2013; · 4.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Injection of effector proteins by a type III secretion system (T3SS) is a common infection strategy employed by many important human pathogens, including enteric Escherichia coli, Salmonella, Yersinia, and Shigella, to subvert cell signaling and host responses. In recent years, great advances have been made in understanding how the T3SS effectors function and execute the diverse infection strategies employed by these pathogens. In this review, we focus on effectors that subvert signaling pathways that impact on endosomal trafficking, cell survival, and innate immunity, particularly phagocytosis, nuclear factor-κB (NF-κB), and mitogen-activated protein (MAP) kinase pathways and the inflammasome.
    Trends in Microbiology 07/2013; · 8.43 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Legionella pneumophila is an intracellular bacterium that resides within amoebae and macrophages in a specialized compartment termed the Legionella containing vacuole (LCV). As well as providing an intracellular niche for replication, the LCV helps to prevent the release of bacterial components into the cytoplasm. Recognition of these components as danger signals by the host activates immune responses leading to clearance of the bacteria. Here, we examined the role of two important virulence factors of L. pneumophila, the potent danger signal flagellin and the translocated Dot/Icm type IVB secretion system effector SdhA, which is crucial to maintain LCV integrity, in the Galleria mellonella infection model. We demonstrate that flagellin expression does not contribute to virulence, replication or induction of clearance mechanisms. Conversely, SdhA expression is important for virulence. We found that in the absence of SdhA, the LCV in haemocytes showed signs of instability and leakage. Furthermore, in contrast to wild type L. pneumophila, a ΔsdhA mutant caused a transient depletion of haemocytes and reduced mortality. Analysis of the ΔsdhA mutant in the A/J mouse model also showed a significant replication defect. Together, our data underline the crucial importance of SdhA in infection across different model organisms.
    Infection and immunity 05/2013; · 4.21 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: L. pneumophila is a water-borne bacterium that causes pneumonia in humans. PlcA and PlcB are two previously defined L. pneumophila proteins with homology to the phosphatidylcholine (PC)- phospholipase C (PC-PLC) of Pseudomonas fluorescens. It is unclear, however, whether L. pneumophila exhibits PLC activity. Therefore we screened the L. pneumophila genome for PLClike genes and additionally found lpg0012, which has been shown to encode a Dot/Icm-injected effector, CegC1, which is designated here as PlcC. PlcC expressed in E. coli hydrolyzed a broad phospholipid spectrum, including PC, phosphatidylglycerol (PG) and phosphatidylinositol. Addition of Zn2+ ions activated, while EDTA inhibited, PlcC-derived PLC activity. Protein screening revealed that the three Legionella enzymes and P. fluorescens PCPLC share conserved domains also present in uncharacterized fungal proteins. Seven conserved amino acids were essential to catalysis as identified via PlcC mutagenesis. Analysis of defined L. pneumophila knock out mutants indicates Lsp-dependent export of PlcA and likely PlcB, both of which exhibit PG-specific activity and contain a predicted Sec signal sequence. Under the condition of expected impaired type IVB secretion, the Dot/Icm effector PlcC showed cell-associated PC-specific PLC activity. Ectopic expression of PlcC in lung epithelial cells resulted in its accumulation in vesicular structures. A PLC triple mutant, but not single or double mutants, exhibited reduced host cell killing in a Galleria mellonella infection model, highlighting the importance of the three PLCs in pathogenesis. In summary, we describe here a novel Zn2+-dependent PLC family present in Legionella, Pseudomonas, and fungi with broad substrate preference and function in virulence.
    Journal of Biological Chemistry 03/2013; · 4.65 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Legionella pneumophila, the causative agent of a severe pneumonia named Legionnaires' disease, is an important human pathogen that infects and replicates within alveolar macrophages. Its virulence depends on the Dot/Icm type IV secretion system (T4SS), which is essential to establish a replication permissive vacuole known as the Legionella containing vacuole (LCV). L. pneumophila infection can be modeled in mice however most mouse strains are not permissive, leading to the search for novel infection models. We have recently shown that the larvae of the wax moth Galleria mellonella are suitable for investigation of L. pneumophila infection. G. mellonella is increasingly used as an infection model for human pathogens and a good correlation exists between virulence of several bacterial species in the insect and in mammalian models. A key component of the larvae's immune defenses are hemocytes, professional phagocytes, which take up and destroy invaders. L. pneumophila is able to infect, form a LCV and replicate within these cells. Here we demonstrate protocols for analyzing L. pneumophila virulence in the G. mellonella model, including how to grow infectious L. pneumophila, pretreat the larvae with inhibitors, infect the larvae and how to extract infected cells for quantification and immunofluorescence microscopy. We also describe how to quantify bacterial replication and fitness in competition assays. These approaches allow for the rapid screening of mutants to determine factors important in L. pneumophila virulence, describing a new tool to aid our understanding of this complex pathogen.
    Journal of Visualized Experiments 01/2013;
  • [Show abstract] [Hide abstract]
    ABSTRACT: The translocation of effector proteins by the Dot/Icm type IV secretion system is central to the ability of Legionella pneumophila to persist and replicate within eukaryotic cells. The subcellular localization of translocated Dot/Icm proteins in host cells provides insight into their function. Through co-staining with host cell markers, effector proteins may be localized to specific subcellular compartments and membranes, which frequently reflects their host cell target and mechanism of action. In this chapter, we describe protocols to (1) localize effector proteins within cells by ectopic expression using green fluorescent protein fusions and (2) localize effector proteins within infected cells using epitope-tagged effector proteins and immuno-fluorescence microscopy.
    Methods in molecular biology (Clifton, N.J.) 01/2013; 954:333-344. · 1.29 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This protocol outlines the steps required to longitudinally monitor a bioluminescent bacterial infection using composite 3D diffuse light imaging tomography with integrated μCT (DLIT-μCT) and the subsequent use of this data to generate a four dimensional (4D) movie of the infection cycle. To develop the 4D infection movies and to validate the DLIT-μCT imaging for bacterial infection studies using an IVIS Spectrum CT, we used infection with bioluminescent C. rodentium, which causes self-limiting colitis in mice. In this protocol, we outline the infection of mice with bioluminescent C. rodentium and non-invasive monitoring of colonization by daily DLIT-μCT imaging and bacterial enumeration from feces for 8 days. The use of the IVIS Spectrum CT facilitates seamless co-registration of optical and μCT scans using a single imaging platform. The low dose μCT modality enables the imaging of mice at multiple time points during infection, providing detailed anatomical localization of bioluminescent bacterial foci in 3D without causing artifacts from the cumulative radiation. Importantly, the 4D movies of infected mice provide a powerful analytical tool to monitor bacterial colonization dynamics in vivo.
    Journal of Visualized Experiments 01/2013;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Phagocytosis is the force-dependent complex cellular process by which immune cells engulf particles. Whilst there has been considerable progress in understanding ligand-receptor-induced actin polymerization in pushing the membrane around the particle, significantly less is known about how localized contractile activities regulate cup closure in coordination with the actin cytoskeleton. Herein, we show that the unconventional class-I myosin, Myosin 1G (Myo1G) is localized at phagocytic cups following Fcγ-receptor (FcγR) ligation in macrophages. This progressive recruitment is dependent on the activity of phosphoinositide 3-kinase and is particularly important for engulfment of large particles. Furthermore, point mutations in the conserved pleckstrin homology-like domain of Myo1G abolishes the localization of the motor protein at phagocytic cups and inhibits engulfment downstream of FcγR. Binding of Myo1G to both F-actin and phospholipids may enable cells to transport phospholipids towards the leading edge of cups and to facilitate localized contraction for cup closure.
    Journal of Cell Science 10/2012; · 5.88 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Legionella pneumophila is a facultative intracellular human pathogen and the etiological agent of severe pneumonia known as Legionnaires' disease. Its virulence depends on protein secretion systems, in particular, the Dot/Icm type IV secretion system (T4SS), which is essential to establish a replication-permissive vacuole in macrophages. The analysis of the role of these systems and their substrates for pathogenesis requires easy-to-use models which approximate human infection. We examined the effectiveness of the larvae of the wax moth Galleria mellonella as a new model for L. pneumophila infection. We found that the L. pneumophila strains 130b, Paris, and JR32 caused mortality of the G. mellonella larvae that was strain, infectious dose, growth phase, and T4SS dependent. Wild-type L. pneumophila persisted and replicated within the larvae, whereas T4SS mutants were rapidly cleared. L. pneumophila strain Lp02, which is attenuated in the absence of thymidine but has a functional T4SS, resisted clearance in G. mellonella up to 18 h postinfection without inducing mortality. Immunofluorescence and transmission electron microscopy revealed that L. pneumophila resided within insect hemocytes in a vacuole that ultrastructurally resembled the Legionella-containing vacuole (LCV) observed in macrophages. The vacuole was decorated with the T4SS effector and LCV marker SidC. Infection caused severe damage to the insect organs and triggered immune responses, including activation of the phenoloxidase cascade leading to melanization, nodule formation, and upregulation of antimicrobial peptides. Taken together, these results suggest that G. mellonella provides an effective model to investigate the interaction between L. pneumophila and the host.
    Infection and immunity 05/2012; 80(8):2780-90. · 4.21 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: EPEC (enteropathogenic Escherichia coli) and EHEC (enterohaemorrhagic Escherichia coli) are attaching and effacing pathogens frequently associated with infectious diarrhoea. EPEC and EHEC use a T3SS (type III secretion system) to translocate effectors that subvert different cellular processes to sustain colonization and multiplication. The eukaryotic proteins NHERF2 (Na(+)/H(+) exchanger regulatory factor 2) and AnxA2 (annexin A2), which are involved in regulation of intestinal ion channels, are recruited to the bacterial attachment sites. Using a stable HeLa-NHERF2 cell line, we found partial co-localization of AnxA2 and NHERF2; in EPEC-infected cells, AnxA2 and NHERF2 were extensively recruited to the site of bacterial attachment. We confirmed that NHERF2 dimerizes and found that NHERF2 interacts with AnxA2. Moreover, we found that AnxA2 also binds both the N- and C-terminal domains of the bacterial effector Tir through its C-terminal domain. Immunofluorescence of HeLa cells infected with EPEC showed that AnxA2 is recruited to the site of bacterial attachment in a Tir-dependent manner, but independently of Tir-induced actin polymerization. Our results suggest that AnxA2 and NHERF2 form a scaffold complex that links adjacent Tir molecules at the plasma membrane forming a lattice that could be involved in retention and dissemination of other effectors at the bacterial attachment site.
    Biochemical Journal 05/2012; 445(3):383-92. · 4.65 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Enteric Escherichia coli (E. coli) are both natural flora of humans and important pathogens causing significant morbidity and mortality worldwide. Traditionally enteric E. coli have been divided into 6 pathotypes, with further pathotypes often proposed. In this review we suggest expansion of the enteric E. coli into 8 pathotypes to include the emerging pathotypes of adherent invasive E. coli (AIEC) and Shiga-toxin producing enteroaggregative E. coli (STEAEC). The molecular mechanisms that allow enteric E. coli to colonize and cause disease in the human host are examined and for two of the pathotypes that express a type 3 secretion system (T3SS) we discuss the complex interplay between translocated effectors and manipulation of host cell signaling pathways that occurs during infection.
    Gut Microbes 03/2012; 3(2):71-87.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC and EHEC) are diarrheagenic pathogens that colonize the gut mucosa via attaching-and-effacing lesion formation. EPEC and EHEC utilize a type III secretion system (T3SS) to translocate effector proteins that subvert host cell signalling to sustain colonization and multiplication. EspH, a T3SS effector that modulates actin dynamics, was implicated in the elongation of the EHEC actin pedestals. In this study we found that EspH is necessary for both efficient pedestal formation and pedestal elongation during EPEC infection. We report that EspH induces actin polymerization at the bacterial attachment sites independently of the Tir tyrosine residues Y474 and Y454, which are implicated in binding Nck and IRSp53/ITRKS respectively. Moreover, EspH promotes recruitment of neural Wiskott-Aldrich syndrome protein (N-WASP) and the Arp2/3 complex to the bacterial attachment site, in a mechanism involving the C-terminus of Tir and the WH1 domain of N-WASP. Dominant negative of WASP-interacting protein (WIP), which binds the N-WASP WH1 domain, diminished EspH-mediated actin polymerization. This study implicates WIP in EPEC-mediated actin polymerization and pedestal elongation and represents the first instance whereby N-WASP is efficiently recruited to the EPEC attachment sites independently of the Tir:Nck and Tir:IRTKS/IRSp53 pathways. Our study reveals the intricacies of Tir and EspH-mediated actin signalling pathways that comprise of distinct, convergent and synergistic signalling cascades.
    Cellular Microbiology 02/2012; 14(7):1051-70. · 4.81 Impact Factor

Publication Stats

5k Citations
873.70 Total Impact Points

Institutions

  • 1995–2014
    • Imperial College London
      • • Division of Cell and Molecular Biology
      • • Centre for Molecular Microbiology and Infection
      Londinium, England, United Kingdom
  • 2013
    • Victoria University Melbourne
      Melbourne, Victoria, Australia
    • University of Massachusetts Medical School
      • Department of Microbiology and Physiological Systems
      Worcester, MA, United States
  • 2010–2013
    • University of Melbourne
      • Department of Microbiology and Immunology
      Melbourne, Victoria, Australia
    • Queen Mary, University of London
      • Barts and The London School of Medicine and Dentistry
      London, ENG, United Kingdom
    • University of Queensland 
      • School of Chemistry and Molecular Biosciences
      Brisbane, Queensland, Australia
    • DNAVEC Corporation
      Ibaragi, Ōsaka, Japan
  • 2012
    • University of Bath
      • Department of Biology and Biochemistry
      Bath, England, United Kingdom
  • 2009–2011
    • Wellcome Trust Sanger Institute
      Cambridge, England, United Kingdom
  • 2002–2010
    • University of Birmingham
      • • School of Biosciences
      • • School of Immunity and Infection
      Birmingham, ENG, United Kingdom
  • 2006–2008
    • Monash University (Australia)
      • Department of Microbiology
      Melbourne, Victoria, Australia
    • Instituto Adolfo Lutz
      San Paulo, São Paulo, Brazil
    • Osaka University
      • Department of Integrated Medicine
      Ōsaka-shi, Osaka-fu, Japan
  • 2007
    • Bundesinstitut für Risikobewertung
      Berlín, Berlin, Germany
    • Miyazaki University
      • Frontier Science Research Center
      Миядзаки, Miyazaki, Japan
  • 2004
    • Hebrew University of Jerusalem
      • Department of Microbiology and Molecular Genetics
      Yerushalayim, Jerusalem District, Israel
    • University College London
      • Centre for Gastroenterology and Nutrition
      London, ENG, United Kingdom
  • 1998–2004
    • Imperial Valley College
      Imperial, California, United States
  • 2003
    • The University of Edinburgh
      • Centre for Tropical Veterinary Medicine
      Edinburgh, SCT, United Kingdom