Escherichia coli DnaA forms helical structures along the longitudinal cell axis distinct from MreB filaments.

DnaA initiates chromosomal replication in Escherichia coli at a well-regulated time in the cell cycle. To determine how the spatial distribution of DnaA is related to the location of chromosomal replication and other cell cycle events, the localization of DnaA in living cells was visualized by confocal fluorescence microscopy. The gfp gene was randomly inserted into a dnaA-bearing plasmid via in vitro transposition to create a library that included internally GFP-tagged DnaA proteins.

Self-efficacy in counseling in Norwegian chain pharmacies: a cross-sectional study.

Background: After pharmacy reform in Norway in 2001, pharmacy chains have systematically trained their personnel in advising self-medication of some symptoms and diseases to increase their competence. It may be important to reveal factors at work that increase self-efficacy in counseling as part of enhancing good pharmacy practice.

Objectives: The aims of this study were to investigate (1) self-efficacy in counseling among pharmacy personnel in respect to a range of medical complaints, and (2) the relationship between self-efficacy in counseling and pharmacy staff's education, age, years of work in pharmacy and psychosocial factors.

A robust screen for novel antibiotics: specific knockout of the initiator of bacterial DNA replication.

We have developed a novel type of a positive screen for the discovery of antibacterial compounds that target the Escherichia coli replication initiator protein DnaA. DnaA is an essential replication protein, conserved in (almost) all bacteria--including all human pathogens--and no existing antibiotics target the main components of the DNA replication machinery. This makes DnaA an attractive target and compounds discovered by this screen will constitute a new group of antibiotics.

Organization of sister origins and replisomes during multifork DNA replication in Escherichia coli.

The replication period of Escherichia coli cells grown in rich medium lasts longer than one generation. Initiation thus occurs in the 'mother-' or 'grandmother generation'. Sister origins in such cells were found to be colocalized for an entire generation or more, whereas sister origins in slow-growing cells were colocalized for about 0.

Specific N-terminal interactions of the Escherichia coli SeqA protein are required to form multimers that restrain negative supercoils and form foci.

The Escherichia coli SeqA protein binds preferentially to hemimethylated DNA and is required for inactivation (sequestration) of newly formed origins. A mutant SeqA protein, SeqA4 (A25T), which is deficient in origin sequestration in vivo, was found here to have lost the ability to form multimers, but could bind as dimers with wild-type affinity to a pair of hemimethylated GATC sites. In vitro, binding of SeqA dimers to a plasmid first generates a topology change equivalent to a few positive supercoils, then the binding leads to a topology change in the "opposite" direction, resulting in a restraint of negative supercoils.

Lack of SeqA focus formation, specific DNA binding and proper protein multimerization in the Escherichia coli sequestration mutant seqA2.

In Escherichia coli wild-type cells newly formed origins cannot be reinitiated. The prevention of reinitiation is termed sequestration and is dependent on the hemimethylated state of newly replicated DNA. Several mutants discovered in a screen for the inability to sequester hemimethylated origins have been mapped to the seqA gene.