News & Events
Stories from the Sea – Predator resistance mechanisms expressed by marine bacteria
Speaker(s): Dr Carla Lutz (SCELSE)
When: 17 September 2015 (9:30)
Where: SBS Classroom 4 (Level 1)
Type: Seminars

Bacteria are dominant organisms in the marine environment, providing the foundation for food webs that are essential for ecosystem structure and function.  The ubiquity of bacteria in the marine environment is a result of their capacity to survive in many different niches.  This is largely due to the evolution of a range of adaptive responses that allow bacteria to survive stressors such as nutrient deprivation, fluctuations in salinity and temperature and to resist lysis by bacteriophage and predation by bacterivorous bacteria and heterotrophic protists. 

This presentation will discuss factors that influence resistance to protozoan grazing, specifically, the role of habitat of origin, such as association with algal surfaces, plays in resistance to predation by the ciliate Tetrahymena pyriformis

In addition, a variety of protozoan grazing resistance mechanisms were detected, including post-ingestional toxicity, biofilm formation and intracellular survival.  One mechanisms studied in detail was intracellular survival within the host.  This mechanism was employed by Shewanella spp. as T. pyriformis feeding on these organisms led to expulsion of Shewanella-filled vacuoles into the external milieu.  The current understanding of the mechanisms that facilitated intracellular survival within Shewanella will be discussed.