Research Interests

Cytoskeleton and motility in plant cells. 

Plant cells have an elaborate cytoskeleton of actin filaments, microtubules, and other proteins.  In small algae such as Chlamydomonas these actually confer motility (swimming), whereas in more advanced plants they are responsible for such tasks as moving chloroplasts into the best position to catch the sunlight without being damaged by it. Recent techniques such as confocal optical microscopy and high-resolution scanning electron microscopy have opened up a new perspective on these structures by providing us with three-dimensional views of their architecture. Flagellar-associated centrin cytoskeleton of Chlamydomonas, revealed by immuno-cytochemistry in conjunction with confocal microscopy.   Guy Cox & Teresa Dibbayawan.

Photosynthesis in prokaryotes

Cyanobacteria and prochlorophyta are technically bacteria, and have a bacterial cell organization, but possess all the photosynthetic chemistry of green plants.

Some cyanobacteria live in caves, where they survive on very little light and may play a significant part in precipitating calcite on stalactites and stalagmites.  With Julia James, Bill Allaway, Neville Michie and Anya Salih I have been studying these using confocal microscopy, electron microscopy and physiological methods.

On the Great Barrier Reef, and on other coral reefs around the world, cyanobacteria and their relatives, the prochlorophyta, live in symbiosis with sponges and ascidians (sea-squirts).  The prochlorophytes are particularly interesting from the point of view of cell evolution since they seem to be long-lost descendants of the ancestor of the chloroplast of green plants.  With Tony Larkum and Teresa Dibbayawan I have been looking at the ultrastructure of both prochlorophytes and symbiotic cyanobacteria on coral reefs.

3-D reconstruction of two types of optical data-sets: cyanobacteria (orange colour) imaged by confocal mode, and calcite crystals (green), imaged by reflection mode of CLSM. (a) A tilt series of the flake surface; (b) a top view of the same flake.

Structure and Ecology of Fluorescent Pigments in Corals

Projection of a 2-photon dataset of Plesiastrea versipora showing the spatial distribution of the pigments. Blue pigments predominate in the upper layers, green in lower layers, and the zooxanthellae (red) lie below both.

Second Harmonic Imaging of Collagen

The novel technique of second harmonic imaging provides a high resolution and extremely sensitive method of studying the three-dimensional distribution of collagen in tissue.