Project description:At hydrothermal vent sites, chimneys consisting of sulfides, sulfates, and oxides are formed upon contact of reduced hydrothermal fluids with oxygenated seawater. The walls and surfaces of these chimneys are an important habitat for vent-associated microorganisms. We used community proteogenomics to investigate and compare the composition and in situ protein expression of microbial communities colonizing two actively venting hydrothermal chimneys from the Manus Basin back-arc spreading center (Papua New Guinea).
Project description:Biological carbon fixation is foundational to the biosphere. Most autotrophs are thought to possess one carbon fixation pathway. The hydrothermal vent tubeworm Riftia pachyptila’s chemoautotrophic symbionts, however, possess two functional pathways: the Calvin Benson-Bassham (CBB) and the reductive tricarboxylic acid (rTCA) cycles. Little is known about how Riftia’s symbionts and related organisms coordinate the functioning of these two pathways. Here we investigated net carbon fixation rates, transcriptional/metabolic responses, and transcriptional co-expression patterns of Riftia pachyptila’s endosymbionts by incubating tubeworms at environmental pressures, temperature, and geochemistry. Results showed that rTCA and CBB transcriptional patterns varied in response to different geochemical regimes and that each pathway is allied to specific metabolic processes, suggesting distinctive yet complementary roles in metabolic function. Net carbon fixation rates were also exemplary, and accordingly we propose that co-activity of CBB and rTCA may be an adaptation for maintaining high carbon fixation rates, conferring a fitness advantage in dynamic vent environments.
Project description:The present study describes the isolation of a Thermococcus sp. strain 175 from the world‘s deepest hydrothermal vent sites known thus far – The Mid-Cayman Rise.consisting of two hydrothermal venting systems Bee Bee (or Piccard), at 4950m depth and Von Damm (or Walsh) at 2300m The strain is capable of growth over 0.1MPa (atm. Pressure) to 120MPa, the widest known range of pressure dependent growth. The study further explores piezophilic adaptation using comparative genomic tools. Insights into the transcriptome of this strain providers the first look into the transcriptional machinery of peizophilic Thermococci.
