Suppressor Mutations in Type II Secretion Mutants of Vibrio cholerae: Inactivation of the VesC Protease.

The type II secretion system (T2SS) is a conserved transport pathway responsible for the secretion of a range of virulence factors by many pathogens, including Disruption of the T2SS genes in results in loss of secretion, changes in cell envelope function, and growth defects. While T2SS mutants are viable, high-throughput genomic analyses have listed these genes among essential genes. To investigate whether secondary mutations arise as a consequence of T2SS inactivation, we sequenced the genomes of six T2SS mutants with deletions or insertions in either the , , or genes and identified secondary mutations in all mutants.

Competition and predation as possible causes of bacterial rarity.

We assembled communities of bacteria and exposed them to different nutrient concentrations with or without predation by protists. Taxa that were rare in the field were less abundant at low nutrient concentrations than common taxa, independent of predation. However, some taxa that were rare in the field became highly abundant in the assembled communities, especially under ample nutrient availability.

Optimization of Methionyl tRNA-Synthetase Inhibitors for Treatment of Infection.

Cryptosporidiosis is one of the leading causes of moderate to severe diarrhea in children in low-resource settings. The therapeutic options for cryptosporidiosis are limited to one drug, nitazoxanide, which unfortunately has poor activity in the most needy populations of malnourished children and HIV-infected persons. We describe here the discovery and early optimization of a class of imidazopyridine-containing compounds with potential for treating infections.

Cultivation-success of rare soil bacteria is not influenced by incubation time and growth medium.

Rare bacterial species have recently attracted interest due to their many potential beneficial functions. However, only little is known about their cultivability. In this study we test the hypotheses that the use of flow cell-sorting for cultivation results in a high proportion of rare soil bacterial isolates relative to bacterial taxa that are abundant in soil.