Industrial microbiology

Engineering Escherichia coli for efficient conversion of glucose to pyruvate Causey, T. B. et al. Proc. Natl Acad. Sci. USA 101, 2235–2240 (2004)

For industrial purposes, the main microorganisms involved in the microbial production of pyruvate — mutant strains of the yeast T. glabrata and E. coli — both require precise regulation of the culture conditions, and the associated production costs are high. This paper reports on the development of an E. coli strain, strain TC44, which, by the appropriate combination of mutations, gives a high yield of pyruvate from glucose and only requires simple mineral salts as nutrients.

Bacterial virulence

Clustering of Nck by a 12-residue Tir phosphopeptide is sufficient to trigger localized actin assembly Campellone, K. G. et al. J. Cell Biol. 164, 407–416 (2004)

Enteropathogenic E. coli attach to intestinal epithelial cells and induce attaching and effacing (A/E) lesions. One of the main features of A/E lesions is the pronounced alteration to the cytoskeleton directly beneath the attached bacterium that results in the formation of an actin pedestal. Now, Campellone et al. report that Tir is the only translocated bacterial effector protein that is required for pedestal formation. Additionally, they have pinpointed a key domain of just 12 amino acids in the carboxyl terminus that is sufficient to induce actin tail formation.

Innate immunity

Inactivation of a Pseudomonas aeruginosa quorum-sensing signal by human airway epithelia Chun, C. K. et al. Proc. Natl Acad. Sci. USA (17 Feb 2004) doi: 10.1073/pnas.0308750101

P. aeruginosa is the main cause of respiratory tract infections in cystic fibrosis patients. Here, Chun et al. demonstrate that an activity associated with differentiated mammalian airway epithelial cells can inactivate the P. aeruginosa quorum-sensing signal molecule 3OC12-HSL. The inactivation of this host defence mechanism could be an important factor in chronic bacterial infections.

Virology

The AU-rich RNA recombination hot spot sequence of brome mosaic virus is functional in tombusviruses: implications for the mechanism of RNA recombination Shapka, N. & Nagy, P. D. J. Virol. 78, 2288–2300 (2004)

This study shows that RNA from a tombusvirus, an RNA virus that is pathogenic to plants, carrying a well-defined recombination signal from a different plant virus, brome mosaic virus, undergoes frequent recombination in both plant and protoplast cells. The recognition of the same recombination signal by different viruses could promote interviral recombination.