Escherichia coli with a linear genome.

Chromosomes in eukaryotes are linear, whereas those of most, but not all, prokaryotes are circular. To explore the effects of possessing a linear genome on prokaryotic cells, we linearized the Escherichia coli genome using the lysogenic lambda-like phage N15. Linear genome E.

Azithromycin inhibits the formation of flagellar filaments without suppressing flagellin synthesis in Salmonella enterica serovar typhimurium.

The present study shows that a sub-MIC of the macrolide antibiotic azithromycin (AZM) diminishes the virulence function of Salmonella enterica serovar Typhimurium. We first constructed an AZM-resistant strain (MS248) by introducing ermBC, an erythromycin ribosome methylase gene, into serovar Typhimurium. The MIC of AZM for MS248 exceeded 100 microg/ml.

Sequential binding of SeqA protein to nascent DNA segments at replication forks in synchronized cultures of Escherichia coli.

To demonstrate that sequestration A (SeqA) protein binds preferentially to hemimethylated GATC sequences at replication forks and forms clusters in Escherichia coli growing cells, we analysed, by the chromatin immunoprecipitation (ChIP) assay using anti-SeqA antibody, a synchronized culture of a temperature-sensitive dnaC mutant strain in which only one round of chromosomal DNA replication was synchronously initiated. After synchronized initiation of chromosome replication, the replication origin oriC was first detected by the ChIP assay, and other six chromosomal regions having multiple GATC sequences were sequentially detected according to bidirectional replication of the chromosome. In contrast, DNA regions lacking the GATC sequence were not detected by the ChIP assay.

Replication-dependent recruitment of the beta-subunit of DNA polymerase III from cytosolic spaces to replication forks in Escherichia coli.

The beta-subunit of DNA polymerase III is located as one or two condensed clusters within the nucleoid-occupied space in exponentially growing cells of Escherichia coli. When chromosome replication is terminated after incubation at nonpermissive temperature in a temperature-sensitive dnaC mutant, the beta-subunit is located in the cytosolic spaces of the cell poles.