David H. Edwards

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Cell division in rod-shaped bacteria is initiated by formation of a ring of the tubulin-like protein FtsZ at mid-cell. Division site selection is controlled by a conserved division inhibitor MinCD, which prevents aberrant division at the cell poles. The Bacillus subtilis DivIVA protein controls the topological specificity of MinCD action. Here we show that(More)
The Bacillus subtilis divIVA gene, first defined by a mutation giving rise to anucleate minicells, has been cloned and characterized. Depletion of DivIVA leads to inhibition of the initiation of cell division. The residual divisions that do occur are abnormally placed and sometimes misorientated relative to the long axis of the cell. The DivIVA phenotype(More)
The existence of endothelium-derived vascular relaxant factor (EDRF) was postulated by Furchgott and colleagues when they observed that acetylcholine paradoxically relaxed preconstricted aortic strip preparations by an endothelium-dependent mechanism. This phenomenon has since been demonstrated in different blood vessels and mammalian species and it can be(More)
The rodA(Sui) mutation allows cell division to take place at 42 degrees C in ftsI23 mutant cells, which produce a thermolabile penicillin-binding protein 3 (PBP3, the septation-specific peptidoglycan transpeptidase). We show here that the mutation in rodA is a single-base change from a glutamine to a chain termination (amber) codon, and that an amber(More)
We have investigated the role of cAMP in NO- and prostanoid-independent relaxations that are widely attributed to an endothelium-derived hyperpolarizing factor (EDHF). Under control conditions EDHF-type relaxations evoked by acetylcholine (ACh) in rabbit iliac arteries were transient, but in the presence of the cAMP phosphodiesterase inhibitor(More)
Although an endothelium-derived hyperpolarizing factor (EDHF) has often been hypothesized to underpin vascular relaxations that are independent of nitric oxide (NO) and prostanoids, bioassay techniques have failed to confirm the existence of a freely transferable EDHF in a consistent fashion. Indeed, observations that inhibitors of direct cell-cell coupling(More)
The Bacillus subtilis divIVA gene encodes a coiled-coil protein that shows weak similarity to eukaryotic tropomyosins. The protein is targeted to the sites of cell division and mature cell poles where, in B.subtilis, it controls the site specificity of cell division. Although clear homologues of DivIVA are present only in Gram-positive bacteria, and its(More)
The characteristic shape of bacterial cells is mainly determined by the cell wall, the synthesis of which is orchestrated by penicillin-binding proteins (PBPs). Rod-shaped bacteria have two distinct modes of cell wall synthesis, involved in cell elongation and cell division, which are believed to employ different sets of PBPs. A long-held question has been(More)
A deletion in the structural gene for the soluble lytic transglycosylase, the predominant murein hydrolase in the soluble fraction of Escherichia coli, has been constructed. The mutant grows normally but exhibits increased sensitivity toward mecillinam, a beta-lactam specific for penicillin-binding protein 2. In the presence of furazlocillin or other(More)
We have developed a mathematical model of arterial vasomotion in which irregular rhythmic activity is generated by the nonlinear interaction of intracellular and membrane oscillators that depend on cyclic release of Ca2+ from internal stores and cyclic influx of extracellular Ca2+, respectively. Four key control variables were selected on the basis of the(More)