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RESEARCH PROJECTS IN THE MARINE SYMBIOSIS LABORATORY

We study cellular interactions in symbiotic associations that consist of animal hosts e.g. corals and zoanthids, and algal symbionts, including:

- host cell signals that regulate the symbionts
- functions of membrane molecules
- effects of pollutants on both host and symbiont

Because of their intracellular location, all symbiont metabolism is under the control of the animal host. We are particularly interested in the biochemistry of cell signals that the animal host uses to regulate symbionts as these signals are essential in maintaining stable symbioses. That is, signals that are essential to avoid expulsion of algae and coral bleaching.

CONTINUING PROJECTS

What is the nature of the coral host signal that stimulates the release of photosynthetic compounds from the symbiotic algae for use in host nutrition?
What mechanisms are involved?
What is the signal that the animal host uses to partially inhibit algal photosynthesis? Which steps in the photosynthesis pathway are involved?
What role does the symbiosome membrane (the animal membrane that surrounds each intracellular alga) play in host-algal interactions?
Does pollution cause deleterious long-term effects on symbiotic associations?
For example, do pollutants cause oxidative damage to the cell signals?

Our recent publications provide background to these projects.

If any of these topics interest you (or you wish to suggest one of your own), contact:

Associate Professor Rosalind Hinde

or Dr. Adrienne Grant

Marine Symbiosis Laboratory, Room 201B,
School of Biological Sciences, A08,
University of Sydney, New South Wales, Australia, 2006.

Some of the techniques that we currently use include:

Measuring photosynthesis:

¹⁴CO₂ experiments for photosynthetic carbon fixation
oxygen electrode
pulse amplitude modulated fluorescence

Fluorimetric, spectroscopic and microscopic analysis:

enzyme assays
pigments
identification of membranes in live cells
determining the location of oxidative damage

Purification of cell signals:

To retain biological activity, wherever possible we avoid destructive methods when isolating bioactive molecules and use:

centrifugal concentration to fractionate molecules (molecular mass cut-off membranes)
ion exchange chromatography
HPLC

To identify signalling molecules and metabolites:

polyacrylamide gel electrophoresis
we have also developed sensitive methods

- to quantify metabolites
- and the products of oxidative damage

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