1. To descirbe and compare the phylogenetic diversity and distribution of the total bacterial flora associated with G catenatum cysts and vegetative cells. 2. To culture and identify bacteria from G catenatum, and identify/characterise any bacteria capable of autonomous PST production in G. catenatum 3. To examine the effect of cyst surface sterilisation and re-introduction of bacteria on PST production in G catenatum 4. Survey bacteria for quorum sensing capability (cell signaling) and detect in situ quorum sesing in xenic G. catenatum cultures, relating to toxicity development. 5. Develop molecular markers of cross species quorum sensing, facilitating analysis of quorum sensing in uncultivated bacteria.