Streptomycetes are mycelial soil bacteria that undergo a complex developmental life cycle on solid media,which is accompanied by production of secondary metabolites, e.g.antibiotics. Streptomyces coelicolor is the model Streptomycete and its 8.7Mb genome h as an unusually high number (965) of putative regulatory genes including 65 sigma factors as well as putative gene clusters involved in anaerobic metabolism. The latter was unexpected as Streptomyces are considered to be obligate aerobes. Recently I have s hown that morphological differentiation of S. coelicolor also occurs in standing liquid culture (SLC). After a period of submerged growth, hyphae migrate to the air interface, where they become fixed by a rigid reflecting film. The resulting colonies form sporulating aerial hyphae. In contrast, shaken liquid cultures of S. coelicolor do not differentiate. In addition, SLCs rapidly become anoxic only 1 to 2mm below the surface, implying the existence of metabolic pathways supporting anaerobic growth or enabl ing the organism to survive long periods of low exygen conditions. The proposed project aims to understand growth, stress responses and developmental pathways at the molecular level in S. coelicolor SLCs. This will be done by identifying differentially exp ressed genes in liquid and solid media using DNA microarrays and proteomics. The roles of the identified genes in morphological differentiation, stress and anaerobic/microaerophilic growth will be investigated using the rapid PCR-di rected gene-disrupti on method developed at the host institute, and through biochemical characterization of selected proteins. The project will be carried out at the John Innes Centre (JIC) under the supervision of Dr. M. Buttner and Dr. G. Sawers. The JIC offers a stimulating research environment as well as world-leading expertise in the analysis of S. coelicolor functional genomics, morpholoogical differentiation, stress responses, and antibiotic biosynthesis.
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