Prof. Tony Larkum
School of Biological Sciences
The University of Sydney, Australia
Phone: +61 7 9351 2069
Fax: +9351 2119
Photosynthesis is the process that underpins all sustainable energy use on the Earth, except nuclear energy. My interests over the last 40 years have centred on photosynthesis, especially in algae and cyanobacteria.
The interests of my laboratory are currently centres on the following topics:
Photosynthesis and Light Harvesting in natural and artificial systems: This work focuses on the pigments and processes that photosynthetic organisms use to capture and harvest solar energy. As a corollary to this it is clear that plants and algae have special mechanisms of down-regulation of light energy (non-photochemical quenching) under excess light. Both aspects of light harvesting are currently studied in my laboratory. A range of microalgae and cyanobacteria are used in these studies. The pulse amplitude mosulated fluorometer is the major tool that we use to investigate these processes together with oxygen electrodes.The Chl d-containing organism Acaryochloris marina has been the focus of our recent studies. In addition our focus has been on prochlorophyte cyanobacterial organisms that containe Chl b. In addition we are working on the following: Synechocystis spp., Synechococcus spp., Gloeobacter violaceus, Cryptomonas, Euglena spp, Symbiodinium microadriaticum, Ostreobium sp.
Coral Reef Ecosystems: Our main focus is currently on coral bleaching. We study the molecular triggers for bleaching in coral and related organisms (zooanthids). Recently we have established a technique for isolating symbiosomes (dinoflagellate symbiont plus host-derived envelope) and of purifying the symbiosome host-derived membrane. We are now carrying out a proteomic analysis of the proteins of the symbiosome membrane with the intention of identifying the key proteins involved in the expulsion of dinoflagellate symbionts during mass bleaching events. We are also investigating the activity of the key CO2-fixing enzyme Rubisco, to establish if this is a primary target of the temperature effects in coral bleaching.
Evolution of photosynthesis: Our focus here has been to compare the strategies that photosynthetic organisms have taken to harvest solar energy. This has involved comparing the detailed protein make-up of anoxygenic photosyntheic bacteria, cyanobacteria and eukaryotic algae.
Bioinformatics: We are using DNA-based Phylogenetic Analysis of Cyanobacteria and Algae to establishe the evolutionary pathway that various organism have taken. In particular we have studied the evolution of the IsiA light-harvesting protein in cyanobacteria and the evolution of cyanobacterial clades. The latter study has involved the development of advanced techniques to compare homologous genes across a wide range of diverse taxa.