Cell division and development of streptomycetes

Our research involves the filamentous soil bacterium Streptomyces. This Gram-positive bacterium is a model system for microbial development: during growth and DNA replication the cells do not separate but elongate and branch, which produces a mycelium network. Below is a schematic representation of the Streptomyces life-cycle.


Influenced by external factors such as starvation or drying out, an aerial mycelium develops with curled hyphae from the tips of which spores are secluded. This results in a complex life-cycle consisting of roughly three phases: vegetative mycelium, aerial mycelium and spores. During transition from vegetative to aerial growth, several secondary metabolites are produced, including antibiotics. In fact, streptomycetes produce about 60% of all known antibiotics, underlining their strong relevance for biotechnology. The pictures below show a cross-section of a Streptomyces coelicolor colony (left) and an electron micrograph of sporulating aerial hyphae (right).

Image courtesy of Dr. J. Ryding.

Image courtesy of John Innes Centre, Norwich, UK.

One of the exciting aspects of the study of streptomycetes is the close relationship between fundamental and applied research. In fact, it is often very difficult to draw the line. For example, Dr. van Wezel holds a KNAW fellowship to study fundamental aspects of cell division, which was for a significant part based on applied research carried out under the flag of STW (dutch applied research council), and now these topics are also an important basis for the new company Mycobics.

We are currently involved in the following subjects:

• Control of morphology: novel regulators of cell division (KNAW project)
• Fragmented growth of Streptomyces by enhancing cell division (STW project)
• Translational control and morphological development (collaboration with Dr. B. Kraal)