Streptomyces:Research

Research

Gabriella Kelemen

Key Research Interests

Our main research interest is studying bacterial development of Streptomyces coelicolor, a Gram-positive, filamentous bacterium. Unlike most bacteria that divide by binary fission, in Streptomyces coelicolor long, multigenomic filaments are formed with ocasional septa and regular branching. Cell division is completed only during sporulation when 50-100 sporulation septa are laid down synchronously in the aerial hyphae generating unigenomic spore compartments.

Current projects include:

• The role of specific RNA polymerase holoenzymes controlling development and stress response
• Global characterisation of spore maturation and germination
• Cytoskeletal proteins
• Chromosome organisation during hyphal growth

Matt Hutchings

Key Research Interests

In order to survive, bacteria must sense and respond to their environment. One of the main ways in which bacteria do this is via two-component signal transduction pathways. In a typical two-component system the extracellular loop of the transmembrane sensor kinase senses a specific signal, autophosphorylates and passes that phosphate group to its cognate response regulator. The activated response regulator then switches on target genes to bring about a response to the original signal (Figure 1).

Figure 1. Classical model for a bacterial two-component signal transduction pathway.

We have been studying these signal transduction pathways in the filamentous bacterium Streptomyces coelicolor. S. coelicolor is the model organism for the genus Streptomyces, a group of bacteria that produce about 80% of commercially important antibiotics. The streptomycetes are soil bacteria and undergo a complex life cycle that includes hyphal growth and sporulation. The S. coelicolor genome encodes 164 two-component proteins, more than nearly any other bacterium. This reflects both its complex life cycle and the highly variable soil environment in which it lives. We are investigating the signal transduction systems of S. coelicolor to work out how streptomycetes sense stresses (such as nutrient starvation and antibiotic attack from competing microorganisms) that trigger antibiotic production and sporulation.

Figure 2. (A) wild type S. coelicolor, (B), a mutant which has lost the ability to sporulate, (C) a strain which overproduces the blue pigmented antibiotic actinorhodin and (D) a cross section of a colony showing the substrate mycelium (sm), aerial mycelium (am) and production of the antibiotic undecylprodigiosin, also known as “red”. Prodigiosins have recently been shown to have strong anti-cancer properties.