Glycine betaine uptake and metabolism in marine microbial communities
Ontology highlight
ABSTRACT: Glycine betaine (GBT) is a component of labile dissolved organic matter and a compatible solute in high concentrations in marine microbial populations. GBT has complex biochemical potential, but, once taken up from the environment, the cellular fate of the carbon and nitrogen from GBT is unknown. Here we determine the uptake kinetics and metabolism of GBT in two natural microbial communities characterized by different nitrate concentrations in the North Pacific transition zone. Dissolved GBT had maximum uptake rates of 0.36 and 0.56 nM hr -1 and half-saturation constants of 79 and 11 nM in the high nitrate and low nitrate stations, respectively. GBT taken into cells was predominantly retained as an untransformed compatible solute. A portion of GBT was transformed into other metabolites, through characterized and uncharacterized pathways. Where nitrate was scarce, GBT was primarily catabolized via the demethylation to glycine. Resulting metabolites were used to build protein biomass, and remineralized ammonia was re-assimilated into cells. Gene expression data from this region show that bacteria, especially SAR11, are the dominant organisms expressing the demethylation genes. Where nitrate concentrations were higher, more GBT was used for choline synthesis. Our data highlight undiscussed metabolic pathways and potential routes of microbial metabolite exchange.
ORGANISM(S): Marine Microbes Natural Mixed Marine Microbial Community
TISSUE(S): Marine Particulate Matter
SUBMITTER: William Kumler
PROVIDER: ST002008 | MetabolomicsWorkbench | Wed Dec 01 00:00:00 GMT 2021
REPOSITORIES: MetabolomicsWorkbench
ACCESS DATA