Cell differentiation in the Caulobacter crescentus cell cycle requires differential gene expression that is regulated primarily at the transcriptional level. Until now, however, a defined in vitro transcription system for the biochemical study of developmentally regulated transcription factors had not been available in this bacterium. We report here the purification of C. crescentus RNA polymer...

A multilocus sequence analysis (MLSA) was established and performed on the genus Thioclava, including 23 strains isolated from diverse marine environments, with the aim of better differentiation of strains and species within this genus. The study was based on sequences of 16S rRNA gene and five protein-coding housekeeping genes, gyrB, rpoD, dnaK, trpB, and recA. In contrast to 16S rRNA gene-bas...

Antarctica harbors a great diversity of microorganisms, including bacteria, archaea, microalgae and yeasts. The Pseudomonas genus is one of the most diverse and successful bacterial groups described to date, but only eight species isolated from Antarctica have been characterized. Here, we present three potentially novel species isolated on King George Island. The most abundant isolates from fou...

Many regulons controlled by alternative factors, including S and , are poorly induced in cells lacking the alarmone ppGpp. We show that ppGpp is not absolutely required for the activity of -dependent promoters because underproduction of , specific mutations in rpoD (rpoD40 and rpoD35), or overproduction of Rsd (anti) restored expression from -dependent promoters in vivo in the absence of ppGpp ...

AIMS To identify bacteria with high selenium tolerance and reduction capacity for bioremediation of wastewater and nanoselenium particle production. METHODS AND RESULTS A bacterial endophyte was isolated from the selenium hyperaccumulator Stanleya pinnata (Brassicaceae) growing on seleniferous soils in Colorado, USA. Based on fatty acid methyl ester analysis and multi-locus sequence analysis ...

The pectinolytic species Pseudomonas viridiflava has a wide host range among plants, causing foliar and stem necrotic lesions and basal stem and root rots. However, little is known about the molecular evolution of this species. In this study we investigated the intraspecies genetic variation of P. viridiflava amongst local (Cretan), as well as international isolates of the pathogen. The genetic...

The bacterial strain 2-92T, isolated from a field plot under long-term (>40 years) mineral fertilization, exhibited in vitro antagonistic properties against fungal pathogens. A polyphasic approach was undertaken to verify its taxonomic status. Strain 2-92T was Gram-reaction-negative, aerobic, non-spore-forming, motile by one or more flagella, and oxidase-, catalase- and urease-positive. The opt...

We describe a "protein knockout" technique that can be used to identify essential proteins in bacteria. This technique uses phage display to select peptides that bind specifically to purified target proteins. The peptides are expressed intracellularly and cause inhibition of growth when the protein is essential. In this study, peptides that each specifically bind to one of seven essential prote...

Characterization of 999 Aeromonas strains using a published 16S rDNA RFLP identification method showed that 8.1% of the strains produced unexpected (hereafter called "atypical") restriction patterns, making their identification uncertain. Atypical patterns were due to the presence of nucleotide polymorphisms among the rrn operons of the 16S rRNA gene (so-called microheterogeneities). Double seq...

Transcription sigma factors direct the selective binding of RNA polymerase holoenzyme (Eσ) to specific promoters. Two families of sigma factors determine promoter specificity, the σ(70) (RpoD) family and the σ(54) (RpoN) family. In transcription controlled by σ(54), the Eσ(54)-promoter closed complex requires ATP hydrolysis by an associated bacterial enhancer-binding protein (bEBP) for the tran...