Aggressive but sustainable bioreactor conversion in ant fungus gardens

Hovedområde:Molecular ecology
Målgruppe:Biology, Biochemistry
Niveau:Masters, Bachelor

Background: When leaf-cutting ants bring home newly collected leaf material to be used as substrate for their fungus garden, they chew leaves into small pieces and add droplets of their own fecal fluid before offering the new substrate to the fungal symbiont.

By subjecting fecal fluid to mass spectrometry analyses, we have identified the ca 100 proteins in the fecal fluid, most of which are produced by the fungal symbiont. Remarkably, they pass the ant digestive tract unharmed because they are only needed for their fecal fluid functions; only a handful of these ca 100 proteins are in fact produced by the ants themselves.

Apart from functions in degradation of the leaf material, these proteins may also have hygienic purposes (e.g. pathogen killing). Some of them also likely serve as somatic incompatibility factors to exclude that related but competing symbiont strains may grow in the same clonal fungus garden.

Recently we have found that the fecal fluid enzymes produce hydroxyl radicals by Fenton chemistry, which operates in small bioreactor-like balls of plant biomass, quite likely to break down recalcitrant plant cell walls very fast. Fenton chemistry is rare in nature because it produces huge amounts of free radicals which give DNA damage.

The human bioconversion industry has tried to use Fenton chemistry, but so far this is not sustainable. We think the ants may have solved the secret, so would like to do further research on this.

Several projects (from 7.5 to 60 ECTS) are available to answer questions like:

-          Stability of fecal fluid enzymes. Are the enzymes involved particularly resistant to proteases and Fenton chemistry?
-          Who is involved and exposed. Is there a correlation between worker age/size and the ability to produce fecal fluid with Fenton reaction activity?
-          How unique? So far we know that only Acromyrmex leafcutter ants make Fenton-balls in their fungus gardens, and it seems Atta leafcutter ants do not use this technique. We would like to know why?
-          Experimental manipulation: Will inhibition of the Fenton reaction affect the ability of fecal fluid to degrade plant substrate?
Competencies to be obtained: Ability to perform biochemical assays, heterologous protein expression, PCR, RT-PCR, droplet digital PCR and RNA extraction

Anvendte metoder:biochemical assays, heterologous protein expression, PCR, RT-PCR, droplet digital PCR, RNA extraction
Keywords:symbiosis, proteomics, evolutionary stability, bioreactors, Panama
Vejleder(e): Jacobus J. Boomsma, Morten Schiøtt