Project description:Studies on temporal changes in the sediment oxygen consumption and bacterial community structure in a seasonally hypoxic enclosed bay, Omura Bay
Project description:Response of sedimentary oxygen consumption and bacterial community composition to temporal re-oxygenation in a seasonally hypoxic enclosed bay
Project description:Marine sediments harbor highly diverse microbial communities that contribute to global biodiversity and play essential roles in the ecosystem functioning. However, the metaproteome of marine sediments remains poorly understood. Extracting proteins from environmental samples can be challenging, especially in marine sediments due to their complex matrix. Few studies have been conducted on improving protein extraction methods from marine sediments. To establish an effective protein extraction workflow for clay-rich sediments, we compared, combined and improved several protein extraction methods. The presented workflow includes blocking of protein binding sites on sediment particles with high concentrations of amino acids, effective cell lysis via ultra-sonication, and the electro-elution and simultaneous fractionation of proteins. Using this workflow, we were able to recover 100% of the previously added Escherichia coli proteins from the sediment.
Project description:Methanogenic and methanotrophic archaea produce and consume the greenhouse gas methane, respectively, using the reversible enzyme methyl-coenzyme M reductase (Mcr). Recently, Mcr variants that can activate multi-carbon alkanes have been recovered from archaeal cultures. These enzymes, called alkyl-coenzyme M reductase (Acrs), are widespread in the environment but remain poorly understood. Here, we produced anoxic cultures degrading mid-chain petroleum n-alkanes from pentane (C5) to tetradecane (C14) at 70°C using oil-rich Guaymas Basin sediments. In these cultures, archaea of the genus Candidatus Alkanophaga activate the alkanes with Acrs and completely oxidize the alkyl groups to CO2. Ca. Alkanophaga form a deep-branching sister clade to the methanotrophs ANME-1 and are closely related to the short-chain alkane oxidizers Ca. Syntrophoarchaeum. Incapable of sulfate reduction, Ca. Alkanophaga shuttle electrons from alkane oxidation to the sulfate-reducing Ca. Thermodesulfobacterium syntrophicum. These syntrophic consortia are potential key players in petroleum degradation in heated oil reservoirs.