Publications by authors named "Mark A Blight"

Escherichia coli haemolysin A (HlyA), an RTX toxin, is secreted probably as an unfolded intermediate, by the type I (ABC transporter-dependent) pathway, utilizing a C-terminal secretion signal. However, the mechanism of translocation and post-translocation folding is not understood. We identified a mutation (hlyA99) at the extreme C terminus, which is dominant in competition experiments, blocking secretion of the wild-type toxin co-expressed in the same cell.

View Article and Find Full Text PDF

Some bacterial phenotypes measured in vitro can be used to access bacterial virulence, on the premise that they are positively correlated with data from in vivo experiments. We show here that in vitro assessment of bacterial phenotypes, such as adherence and cytotoxicity, are positively correlated with data from in vivo experiments in Drosophila and can be used to assess bacterial virulence in vivo. Manipulation of environmental parameters, such as iron availability, induced changes in the phenotypes measured in vitro that correlated with changes in vivo virulence of all strains tested.

View Article and Find Full Text PDF

The ATPase activity of the ABC (ATP-binding cassette) ATPase domain of the HlyB (haemolysin B) transporter is required for secretion of Escherichia coli haemolysin via the type I pathway. Although ABC transporters are generally presumed to function as dimers, the precise role of dimerization remains unclear. In the present study, we have analysed the HlyB ABC domain, purified separately from the membrane domain, with respect to its activity and capacity to form physically detectable dimers.

View Article and Find Full Text PDF

By enriching a random transposon insertion bank of Pseudomonas fluorescens for mutants affected in their adherence to the human extracellular matrix protein fibronectin, we isolated 23 adherence minus mutants. Mutants showed a defect in their ability to develop a biofilm on an abiotic surface and were impaired for virulence when tested in an in vivo virulence model in the fruit fly, Drosophila melanogaster. Molecular characterisation of these mutants showed that the transposon insertions localised to two distinct chromosomal locations, which were subsequently cloned and characterised from two mutants.

View Article and Find Full Text PDF

The ABC-transporter haemolysin B is a central component of the secretion machinery that translocates the toxin, haemolysin A, in a Sec-independent fashion across both membranes of E. coli. Here, we report the X-ray crystal structure of the nucleotide-binding domain (NBD) of HlyB.

View Article and Find Full Text PDF

Proteases play a key role in the interaction between pathogens and their hosts. The bacterial entomopathogen Photorhabdus lives in symbiosis with nematodes that invade insects. Following entry into the insect, the bacteria are released from the nematode gut into the open blood system of the insect.

View Article and Find Full Text PDF

A member of the family of RTX toxins, Escherichia coli haemolysin A, is secreted from Gram-negative bacteria. It carries a C-terminal secretion signal of approximately 50 residues, targeting the protein to the secretion or translocation complex, in which the ABC-transporter HlyB is a central element. We have purified the nucleotide-binding domain of HlyB (HlyB-NBD) and a C-terminal 23kDa fragment of HlyA plus the His-tag (HlyA1), which contains the secretion sequence.

View Article and Find Full Text PDF

The entomopathogen Photorhabdus luminescens secretes many proteins during the late stages of insect larvae infection and during in vitro laboratory culture. The authors have previously characterized and purified a 55 kDa zinc metalloprotease, PrtA, from culture supernatants of P. luminescens.

View Article and Find Full Text PDF

Haemolysin B (HlyB) is a transmembrane protein which belongs to the superfamily of ABC transporters. In vivo, it mediates the non-classical translocation of the 107 kDa toxin HlyA across both membranes of Escherichia coli together with haemolysin D and the outer membrane protein TolC. The cytosolic ATP-binding domain of HlyB has been overexpressed and purified as an N-terminal His-tag fusion protein.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_session3km73m6aahsmhmp3m7nu2s0vfoahuiec): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once