Meeting Abstract

P2.196A  Monday, Jan. 5  Exploring the Boundaries of Metazoan Thermotolerance at Hydrothermal Vents: Respiration and Protein Expression of Paralvinellid Worms DILLY, G.F.*; GIRGUIS, P.R.; Harvard University; Harvard University gdilly@fas.harvard.edu

Eukaryotic thermotolerance is pushed to its limits at one of the most extreme ecosystems on the planet, deep-sea hydrothermal vents. Temperatures around vent sulfides (or chimneys) range from 2C to well over 300C. This wide thermal regime has given rise to some of the most thermally tolerant organisms on earth including the annelid Paralvinella sulfincola. These worms are found at vents on the Juan de Fuca Ridge, in 2200m water depths off the coast of Washington, USA. Paralvinellids are amenable to recovery and shipboard experimentation and can withstand prolonged exposure to temperatures between 5C and 55C, one of the largest thermal ranges known.

Our experiments utilize live worms in flow-through chambers at in situ pressure and chemistry that replicate vent conditions. Coupling high-pressure respirometry with tandem mass spectrometry, this work examines oxygen consumption rates and differential protein expression of P. sulfincola and P. palmiformis, maintained under two thermal regimes (30 and 53C, and 12 and 35C respectively). Our data suggest that P. sulfincola exposed to 53C exhibit an up-regulation of proteins involved in maintaining cellular structure and a down-regulation of enzymes associated with energy metabolism. Surprisingly, P. sulfincola exhibited high concentrations of HSP70 in both treatments. We suggest that the continual production of HSPs, as well as an increased synthesis of proteins that confer structural stability allow P. sulfincola to survive exposure to temperatures greater than 50C. These data provide the first insights into the biochemical factors that enable an organism to exist at the edge of eukaryotic thermotolerance.