Stephen Michell

Learn More
Francisella tularensis is one of the most infectious human pathogens known. In the past, both the former Soviet Union and the US had programs to develop weapons containing the bacterium. We report the complete genome sequence of a highly virulent isolate of F. tularensis (1,892,819 bp). The sequence uncovers previously uncharacterized genes encoding type IV(More)
Epidemic C. difficile (027/BI/NAP1) has rapidly emerged in the past decade as the leading cause of antibiotic-associated diarrhea worldwide. However, the key events in evolutionary history leading to its emergence and the subsequent patterns of global spread remain unknown. Here, we define the global population structure of C. difficile 027/BI/NAP1 using(More)
The Mycobacterium bovis antigens MPB70 and MPB83 are homologous cross-reactive proteins. It has been reported previously that MPB83 is glycosylated and exists in two forms with apparent molecular masses of 23kDa and 25kDa, whereas the apparent molecular mass of MPB70 is 22kDa. Using a monoclonal antibody, SB10, which recognizes an epitope common to both(More)
Bacterial lipoproteins are a set of membrane proteins with many different functions. Due to this broad-ranging functionality, these proteins have a considerable significance in many phenomena, from cellular physiology through cell division and virulence. Here we give a general overview of lipoprotein biogenesis and highlight examples of the roles of(More)
We have determined the sequence of the gene cluster encoding the O antigen in Francisella novicida and compared it to the previously reported O-antigen cluster in Francisella tularensis subsp. tularensis. Immunization with purified lipopolysaccharide (LPS) from F. tularensis subsp. tularensis or F. novicida protected against challenge with Francisella(More)
Mycobacterium tuberculosis and Mycobacterium bovis, the causative agents of human and bovine tuberculosis, have been reported to express a range of surface and secreted glycoproteins, although only one of these has been subjected to detailed structural analysis. We describe the use of a genetic system, in conjunction with lectin binding, to characterize the(More)
Burkholderia pseudomallei is the causative agent of melioidosis, a tropical disease of humans with a variable and often fatal outcome. In murine models of infection, different strains exhibit varying degrees of virulence. In contrast, two related species, B. thailandensis and B. oklahomensis, are highly attenuated in mice. Our aim was to determine whether(More)
Tularemia is a geographically widespread, severely debilitating, and occasionally lethal disease in humans. It is caused by infection by a gram-negative bacterium, Francisella tularensis. In order to better understand its potency as an etiological agent as well as its potential as a biological weapon, we have completed draft assemblies and report the first(More)
In Francisella tularensis subsp. tularensis, DsbA has been shown to be an essential virulence factor and has been observed to migrate to multiple protein spots on two-dimensional electrophoresis gels. In this work, we show that the protein is modified with a 1,156-Da glycan moiety in O-linkage. The results of mass spectrometry studies suggest that the(More)
Francisella tularensis, the causative agent of tularaemia, is a highly infectious and virulent intracellular pathogen. There are two main human pathogenic subspecies, Francisella tularensis ssp. tularensis (type A), and Francisella tularensis ssp. holarctica (type B). So far, knowledge regarding key virulence determinants is limited but it is clear that(More)