Exploration

From ActinoBase

General overview

Exploration is an alternative developmental stage of Actinobacteria consisting of rapid horizontal hyphal growth on YP agar, or YPD agar in the presence of certain fungi, with little to no branching. The exploring colony will also produce volatile organic compounds which induce exploration in distal colonies. Not every Actinobacteria is capable of exploring but was first described in Streptomyces venezuelae along with others [1].

Useful host strains:

  • Streptomyces venezuelae [1]

This species is currently the most well characterised for exploration.

Abiotic induction protocol:

  • Make 33-50mL YP plates
  • Inoculate 5μL of bacterial spore stock in the centre of the plate
  • Incubate at 30ºC for 14 days
  • Image plate

This protocol is more reliable as you are not reliant on the activity of the yeast co-culture

Biotic induction protocol:

  • Grow Saccharomyces cerevisiae in an overnight culture of liquid YPD
  • Make 33-50mL YPD plates
  • Inoculate 5μL of bacterial spore stock in the centre of the plates
  • Inoculate 5μL of Saccharomyces cerevisiae overnight culture next to the other inoculation and blend gently
  • Incubate at 30ºC for 14 days
  • Image plate

This protocol can be less reliable due to the nature of the yeast co-culture but allows for reciprocal testing if required.

References: [1] Jones, S., Ho, L., Rees, C., Hill, J., Nodwell, J. and Elliot, M. (2017). Streptomyces exploration is triggered by fungal interactions and volatile signals. eLife, 6.

Protocol adapted for Actinobase by Thomas C. McLean, The University of East Anglia