Discovery of invertebrate attractants and toxins from diverse Actinomycetes

Actinomycetes are useful bacteria which produce compounds that are widely used in medicine. This project hopes to further their clinical use by examining how the bacteria interact with various insects.

The goal of this project is to:

1. Use insect model systems to investigate attractant and repellent phenotypes of around 1000 individual actinomycete isolates.

The details

The Actinomycetes are a group of bacteria. They produce an array of small molecules known as specialised metabolites. These chemicals are widely used in a variety of clinical medicine. Examples include antibiotics, antifungals, immunosuppressants and anticancer agents.

They can also affect other organisms apart from humans. In nature, actinomycete bacteria have been shown to form mutually beneficial associations with insects. For example, leaf-cutter ants have been observed cultivating actinomycetes. The bacteria produce a range of antibiotics to protect the ants' fungal food source from infection. Likewise, Philanthus wasps coat their larvae with antibiotic-producing bacteria to protect them from infection. Yet many examples also exist of actinomycetes producing molecules that are toxic to bugs. The actinomycete Streptomyces avermitilis produces a substance called avermectin, which is highly toxic to parasitic worms. Humans have used this property to cure diseases caused by the worms, such as river blindness. These are just some examples of how actinomycetes are used in the creation of insect attractants and repellants. However, there is still an opportunity to conduct more research in this area.

This project will use several insect model systems to investigate attractant and repellant (or toxic) phenotypes of ~1000 individual actinomycete isolates. Individual actinomycetes producing the desired phenotype will be selected and the responsible compounds will be isolated and have their structures fully elucidated. At the same time, the selected isolates will have their genomes sequenced to inform the development of mutant strains that will connect genes to molecules.

This project aims to provide a range of previously unseen invertebrate-active compounds. This will provide a pathway for further development and clinical use.

Supervision team

The University of Melbourne: Dr Sacha Pidot

The University of Toronto: Professor Justin Nodwell