Martin J. Callaghan

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  • Alain Patoine, Mark D Graham, Peter R Leavitt, Lorelei Benoit, Martin Callaghan, Brianna Dopson +4 others
  • 2006
Cyanobacterial blooms are a regular feature of lakes in central North America, but little is known of their importance to the nitrogen (N) cycle and nutrition of aquatic food webs. We hypothesized that N 2-fixing cyanobacteria constitute a significant source of N to prairie lakes, that fixed N is effectively transferred to primary and secondary consumers,(More)
Phase variable restriction-modification (R-M) systems are widespread in Eubacteria. Haemophilus influenzae encodes a phase variable homolog of Type III R-M systems. Sequence analysis of this system in 22 non-typeable H.influenzae isolates revealed a hypervariable region in the central portion of the mod gene whereas the res gene was conserved. Maximum(More)
The opa genes of the Gram negative bacterium Neisseria meningitidis encode Opacity-associated outer membrane proteins whose role is to promote adhesion to the human host tissue during colonisation and invasion. Each meningococcus contains 3-4 opa loci, each of which may be occupied by one of a large number of alleles. We analysed the Opa repertoire(More)
Clusters of meningococcal disease caused by a hyperinvasive lineage of Neisseria meningitidis, the ST11 complex, bearing a serogroup C polysaccharide capsule, have been prominent in Europe and North America since the early 1990s. This situation has led to expensive public health measures for outbreak control and, finally, to the introduction of a serogroup(More)
Neisseria meningitidis is a major global pathogen causing invasive disease with a mortality of 5-10%. Most disease in developed countries is caused by serogroup B infection, against which there is no universal vaccine. Opacity-associated adhesin (Opa) proteins are major meningococcal outer membrane proteins, which have shown recent promise as a potential(More)
One potential vaccine strategy in the fight against meningococcal disease involves the exploitation of outer-membrane components of Neisseria lactamica, a commensal bacterium closely related to the meningococcus, Neisseria meningitidis. Although N. lactamica shares many surface structures with the meningococcus, little is known about the antigenic diversity(More)
System dynamics simulation models provide a powerful and rigorous means of evaluating management options in dynamically complex settings such as a metro subway system. This paper explores how a system dynamics model has been used over several years to address a variety of management challenges at London Underground. Several short case illustrations are(More)
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