Research lab at the University of California Santa Cruz working to understand the evolutionary and molecular mechanisms underlying host-symbiont interactions.
Research Systems: Chemosynthetic Symbioses
Marine bivalve-bacteria chemosynthetic systems: tractable model system for marine nutritional symbioses (e.g., hydrothermal vent symbioses)
“And the most extreme examples of this mutually assured success can be found in the deep oceans, where some microbes supplement their hosts to such a degree that the animals can eat the most impoverished diets of all – nothing.” ― Ed Yong, I Contain Multitudes: The Microbes Within Us and a Grander View of Life
Using Illumina short read and Nanopore long read sequencing, we have characterized the transmission dynamics and population genomic diversity of marine bivalves and their chemosynthetic symbionts across the full range of transmission modes in order to assess the impact horizontal transmission and recombination have on symbiont genome evolution (see Publications). Future work will use the tractable S. velum system described below to understand the cellular and metabolic interactions that underpin this association.
The Atlantic Awning Clam, Solemya velum, in its y-shaped burrow in a mudflat in Point Judith, RI. In these burrows, the bivalves acquire oxygenated seawater by pumping it from above, and sulfidic porewater diffuses through the tunnel leading from the bottom of the burrow. Sitting at this crucial juncture in the burrow, S. velum provides reduced sulfide to its symbionts for chemosynthetic fixation of carbon dioxide and synthesis of ATP, which feeds this association. Associations nearly phylogenetically and functionally identical to this sustain the dense communities at hydrothermal vents, cold seeps, whale falls, and wood falls around the world.
S. Russell collecting S. velum from Great Bay, NJ intertidal sediments with a shovel and sieve
S. velum collected from Point Judith, RI and maintained in filtered seawater in the lab. Watch the video to see how they are able to use their foot to move through the water, but be patient. They only move intermittently.
S. velum cultured in aquaria with reducing sediment from their habitat (Point Judith, RI) prior to burying themselves and constructing their y-shaped burrow
Juvenile S. velum spawned and fertilized in the lab, still contained within its egg capsule (i.e, vitelline membrane)
Fluorescence in situ hybridization (FISH) staining of S. velum gill tissue containing gammaproteobacterial symbionts (red = symbiont 16S rRNA; blue = nuclei)
