A5018192461- Clostridium difficile and Clostridium perfringens research
- Toxin Mechanisms and Immunotoxins
- Botulinum Toxin and Related Neurological Disorders
- Antimicrobial Resistance in Staphylococcus
- Bacteriophages and microbial interactions
- Viral gastroenteritis research and epidemiology
- Bacterial Infections and Vaccines
- Biochemical and Structural Characterization
- Bacterial Genetics and Biotechnology
- Helicobacter pylori-related gastroenterology studies
- Salmonella and Campylobacter epidemiology
- Glycosylation and Glycoproteins Research
- Microscopic Colitis
- RNA and protein synthesis mechanisms
- Streptococcal Infections and Treatments
- Escherichia coli research studies
- Monoclonal and Polyclonal Antibodies Research
- Nerve injury and regeneration
- Antibiotic Resistance in Bacteria
- Diphtheria, Corynebacterium, and Tetanus
- Gut microbiota and health
- Bacterial Identification and Susceptibility Testing
- Plant-based Medicinal Research
- Microbial infections and disease research
- Cancer therapeutics and mechanisms
Imperial College London
2014-2024
Saudi Aramco (Saudi Arabia)
2023
Apache (Canada)
2012
Czech Academy of Sciences, Biology Centre
2011
Kyoto Institute of Technology
2008
Imperial Valley College
2000
Wellcome Trust
1987-1996
University of Glasgow
1993-1996
University of Dundee
1995
University of Cambridge
1994
Clostridium difficile persists in hospitals by exploiting an infection cycle that is dependent on humans shedding highly resistant and infectious spores. Here we show human virulent C. can asymptomatically colonize the intestines of immunocompetent mice, establishing a carrier state for many months. mice consistently shed low levels spores but, surprisingly, do not transmit to cohabiting mice. However, antibiotic treatment carriers triggers contagious supershedder state, characterized...
ABSTRACT Clostridium difficile is a major cause of chronic antibiotic-associated diarrhea and significant health care-associated pathogen that forms highly resistant infectious spores. Spo0A conserved transcriptional regulator plays key role in initiating sporulation Bacillus species. Here, we use murine model to study the C. spo0A gene during infection transmission. We demonstrate mutant derivatives can intestinal disease but are unable persist within effectively transmit between mice....
Protein translocation across the cytoplasmic membrane is an essential process in all bacteria. The Sec system, comprising at its core ATPase, SecA, and a channel, SecYEG, responsible for majority of this protein transport. Recently, second parallel system has been described number Gram-positive species. This accessory characterized by presence copy energizing SecA2; where it studied, SecA2 subset substrates. In common with many pathogenic species, Clostridium difficile possesses two copies...
Bound antibodies can modulate antigen processing but it is not clear to what extent this affects presentation. Here we show that presentation of T cell determinants in tetanus toxin be either enhanced or suppressed as a direct consequence antibody modulation human B lymphoblastoid cells. Remarkably, single bound its Fab fragment simultaneously enhance the one determinant by more than 10-fold while strongly suppressing different determinant. Biochemical analysis demonstrates both and boosted...
ABSTRACT Clostridium difficile is the etiological agent of antibiotic-associated diarrhea, a potentially serious condition frequently affecting elderly hospitalized patients. While tissue damage primarily induced by two toxins, mechanism gut colonization, and particularly role bacterial adherence to mucosa, remains be clarified. Previous studies have shown binding C. whole cells cultured cell lines suggested existence multiple adhesins, only one which has been molecularly characterized. In...
ABSTRACT For the first time, bacterial spores have been evaluated as vaccine vehicles. Bacillus subtilis displaying tetanus toxin fragment C (TTFC) antigen were used for oral and intranasal immunization shown to generate mucosal systemic responses in a murine model. TTFC-specific immunoglobulin G titers serum (determined by enzyme-linked immunosorbent assay) reached significant levels 33 days after dosing, while against spore coat proteins relatively low. Tetanus antitoxin sufficient protect...
The gp63 gene of Leishmania major was transformed into the AroA- vaccine strain Salmonella typhimurium (SL3261). construct (SL3261-gp63), which stably expresses Ag in vitro, used to immunize CBA mice by oral route. Spleen cells from inoculated with SL3261-gp63 developed antibody and proliferative T cell response L. major. They did not express detectable delayed-type hypersensitivity reactivity. activated are mainly CD4+ secrete IL-2 IFN-gamma but no IL-4. orally immunized significant...
Protein P.69 is localized on the outer membrane of Bordetella pertussis and one virulence factors believed to contribute disease state whooping cough. We demonstrate that protein synthesis under genetic control vir locus. Using oligonucleotide probes derived from sequence a cyanogen bromide fragment, we have cloned gene for B. CN2992. Analysis DNA reveals G + C-rich capable encoding 910 amino acids with Mr 93,478, suggesting processed form larger precursor. In common some genes in toxin...
Clostridium difficile is the most common cause of antibiotic-associated intestinal infections and a significant morbidity mortality. Infection with C. requires disruption microbiota, commonly by antibiotic usage. Therapeutic intervention largely relies on small number broad-spectrum antibiotics, which further exacerbate dysbiosis leave patient acutely sensitive to reinfection. Development novel targeted therapeutic interventions will require detailed knowledge essential cellular processes,...
Spores of Clostridium difficile play a key role in the dissemination this important human pathogen, and until recently little has been known their functional characteristics. Genes encoding six spore coat proteins (cotA, cotB, cotCB, cotD, cotE, sodA) were disrupted by ClosTron insertional mutagenesis. Mutation one gene, cotA, presented major structural defect assembly, with clear misassembly outermost layers coat. The CotA protein is most probably subject to posttranslational modification...
Abstract Many bacteria and archaea possess a two-dimensional protein array, or S-layer, that covers the cell surface plays crucial roles in physiology. Here, we report crystal structure of SlpA, main S-layer bacterial pathogen Clostridioides difficile , use electron microscopy to study organisation assembly. The SlpA lattice mimics assembly cell, through tiling triangular prisms above wall, interlocked by distinct ridges facing environment. Strikingly, array is very compact, with pores only...
Many bacteria express a surface‐exposed proteinaceous layer, termed the S‐layer, which forms regular two‐dimensional array visible by electron microscopy. Clostridium difficile is unusual in expressing two S‐layer proteins (SLPs), are of varying size number strains. In an approach combining molecular biology with mass spectrometric sequencing strategies, we have identified structural gene ( slpA ) for from three strains C. . Both derived common precursor, and processing involves removal...
Tetanus toxin, a member of the family of<i>Clostridial</i> neurotoxins, is one most potent toxins known. The crystal structure complex COOH-terminal fragment heavy chain with an analogue its ganglioside receptor, GT1b, provides first direct identification and characterization ganglioside-binding sites. induces cross-linking by binding to two distinct sites on Hc molecule. sheds new light neurotoxins receptors neuronal cells important information relevant design anti-tetanus anti-botulism...
Journal Article Expression of tetanus toxin fragment C in E.coli : high level expression by removing rare codons Get access A.J. Makoff, Makoff * To whom correspondence should be addressed Search for other works this author on: Oxford Academic PubMed Google Scholar M.D. Oxer, Oxer M.A. Romanos, Romanos N.F. Fairweather, Fairweather S. Ballantine 1Departments Protein ChemistryWellcome Biotech, Langley Court, Beckenham, Kent BR3 3BS, UK Nucleic Acids Research, Volume 17, Issue 24, 25 December...
The entry of tetanus neurotoxin into neuronal cells proceeds through the initial binding toxin to gangliosides on cell surface. carboxyl-terminal fragment heavy chain contains ganglioside-binding site, which has not yet been fully characterized. crystal structures native H(C) and soaked with carbohydrates reveal a number sites provide insight possible mode ganglioside binding.
Clostridium difficile expresses a surface layer (S-layer) which coats the of bacterium and acts as an adhesin facilitating interaction with host enteric cells. The S-layer contains high-molecular-weight protein (HMW SLP) its low-molecular-weight partner (LMW SLP). We show that these proteins form tightly associated non-covalent complex, H/L we identify regions both responsible for complex formation. 2.4 A X-ray crystal structure truncated derivative LMW SLP reveals two domains. Domain 1 has...
Two recombinant plasmids, pTet11 and pTet18, which express nontoxic protein fragments of tetanus toxin in Escherichia coli, were constructed. (86 kilodaltons) is a fusion between part the E. coli trpE 441 amino acids fragment C, pTet18 (63 consists B all C toxin. The synthesis these proteins was induced cultures, partially purified. Mice immunized with proteins, dose-dependent titers anti-tetanus toxoid antibodies obtained. able to induce neutralizing mice, as demonstrated by ability mice 1...
A Salmonella typhimurium aroA mutant has been used as a live carrier to immunize mice against tetanus. Plasmid pTETtac4, which expresses 50-kilodalton fragment of tetanus toxin (fragment C) under the control tac promoter, was introduced into SL3261 aroA. When vaccine and administered orally or intravenously, this strain able induce protective immunity in lethal challenge. plasmid pTETtac2, contains lacI gene, used, no obtained, indicating that expression C repressed vivo. We believe is first...
Clostridium difficile is a leading cause of nosocomial infection in the developed world. Two toxins, A and B, produced by most strains C. are implicated as virulence factors, yet only recently has requirement these for been investigated genetic manipulation. Current vaccine strategies focused mostly on parenteral delivery toxoids. In this work, we have used bacterial spores (Bacillus subtilis) vehicle to evaluate carboxy-terminal repeat domains toxins B protective antigens. Our findings...