ORGANISMIC INTERACTIONS

‘When we try to pick out anything by itself, we find it bound fast by a thousand invisible cords that cannot be broken, to everything else in the Universe’ – John Muir, 1869

Diatoms photosynthetic organisms that account for roughly one-fifth of global primary production, and are the microbial engines that drive global cycling of the six major elements (hydrogen, carbon, nitrogen, oxygen, sulphur and phosphorus)1. Diatoms are also cultivated for use in fields such as aquaculture industries (mainly as feed for fish larvae), in nutraceutical and pharmaceutical industries, in bioremediation, and nanotechnology (mainly due to the intricate silica nanostructures they possess).

However, diatoms are not found in monocultures in nature – they are part of a complex microbiome. Bacteria and diatoms, in particular, have coexisted in habitats throughout the oceans for more than 200 million years2, and gaining insight into this relationship will allow us to increase our understanding of phenomena such as nutrient cycling in our oceans and the mechanisms of Harmful Algal Blooms (HABs) which could possibly allow us to predict and/or control them.

Furthermore, the potential inclusion of bacteria to microalgal biotechnology is of particular industrial interest. After all, probiotic gut bacteria are used routinely as a prophylactic against bacterial disease in animal production, since they exhibit natural mechanisms of competitive exclusion against pathogenic competitors. This could be achieved in large-scale cultures through the creation of a ‘synthetic ecosystem’3, where the species-rich community utilises all resources available because every possible niche is occupied, avoiding competition and so productivity is maximised. Studying species-specific bacterial-microalgal interactions may encourage the growth of favourable bacteria that will enhance the growth of the diatom through the provision of expensive nutrients such as vitamin B12 or iron, therefore keeping production costs down.

MODELLING APPROACH

Reconstructions of an organism's metabolic network at the genome scale contain precious information that can be used to understand metabolic interactions between different species. Co-factors such as vitamin B12 are of particular interest in bacterial-microalgal interactions, but their action is currently ignored in constraint-based model approaches like Flux Balance Analysis (FBA). We are working on including dynamic effects in FBA that can capture such important mechanisms. This will allow for in silico testing of possible synthetic communities.

Contact: Fiona Moejes M. BiolSci, Dr. Antonella Succurro, Dipl. Biol. Ovidiu Popa

Further reading

  1. Falkowski, P. G., Fenchel, T. and Delong, E. F. The microbial engines that drive Earth’s biogeochemical cycles. Science 320, 1034–9 (2008).
  2. Amin, S., Parker, M. S. and Armbrust, E. V. Interactions between diatoms and bacteria. Microbiol. Mol. Biol. Rev. 76, 667–84 (2012).
  3. Kazamia, E., Aldridge, D. C. and Smith, A. G. Synthetic ecology – A way forward for sustainable algal biofuel production? J. Biotechnol. 162, 163–169 (2012).

Verantwortlich für den Inhalt: E-Mail sendenPascal Spinnrath