Marine N-osmolytes

Nitrogen-containing compounds, including glycine betaine (GBT), choline and trimethylamine N-oxide (TMAO) are ubiquitous in marine organisms. They are used by marine organisms as compatible solutes in response to changes in environmental conditions, such as increasing salinity, because they do not interfere with cell metabolism. They also have beneficial effects in protecting proteins against denaturation due to chemical or physical damage. In the marine environment, these compounds are frequently released from these organisms directly into seawater due to changing environmental conditions, such as by viral lysis or grazing. The released nitrogenous osmolytes serve as important nutrients for marine microorganisms, which can use them as carbon, nitrogen and energy sources. We have a unique opportunity within the Antarctic Circumnavigation Expedition (ACE) to make measurements and collect samples around the entire Southern Ocean, and near Antarctica. This proposal aims to develop a new international network with six ACE projects and use post-cruise activities to exploit data and knowledge generated to capitalise on our NERC-funded research on nitrogenous osmolytes and to increase its international breadth.

 

Project investigators: Dr Ruth Airs (Plymouth Marine Laboratory).

Co-I, Dr Y Chen, Dr R Beal, Dr M Fitzsimons, Dr L Polimene.

Nitrogen-containing compounds, including glycine betaine, choline and trimethylamine oxide are ubiquitous in marine organisms. They are used by marine organisms as compatible solutes in response to changes in environmental conditions, such as increasing salinity, because they do not interfere with cell metabolism. They also have beneficial effects in protecting proteins against denaturation due to chemical or physical damage. In the marine environment, these compounds are frequently released from these organisms directly into seawater due to changing environmental conditions, such as by viral lysis or grazing. The released nitrogenous osmolytes serve as important nutrients for marine microorganisms, which can use them as carbon, nitrogen and energy sources. It is well known that the degradation of these nitrogenous osmolytes contribute to the release of climate-active gases, including volatile methylated amines. Methylated amines are important sources of aerosols in the marine atmosphere, which help to reflect sunlight and cause a cooling effect on the climate. There is an urgent need to understand the microbial metabolism of these compounds and their seasonal cycles in the marine water column, in order to better understand their role in marine biogeochemical cycles and their role in future climate change, which is the aim of this project.

 

Postdoctoral research fellow: Dr Michaela Mausz

Project investigators: Dr Yin Chen (University of Warwick), Prof David Scanlan (University of Warwick)

Project collaborators: Dr Ruth Airs (Plymouth Marine Laboratory), Dr Luca Polimene (Plymouth Marine Laboratory), Dr Wei HuangLink opens in a new window (University of Oxford)

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• A Mausz, RL Airs, JL Dixon, CE Widdicombe, GA Tarran, L Polimene,  et al Microbial uptake dynamics of choline and glycine betaine in coastal seawater. Limnology and Oceanography 67 (5), 1052-1064. 

• RL Airs, R Beale, L Polimene, Y Chen, MA Mausz, DJ Scanlan et al Seasonal measurements of the nitrogenous osmolyte glycine betaine in marine temperate coastal waters. Biogeochemistry 162 (3), 309-323

• HJ Jones, E Krober*, J Stephenson, M Mausz, E Jameson, A Millard, KJ Purdy, Y Chen* (2019) A new family of uncultivated bacteria involved in methanogenesis from the ubiquitous osmolyte glycine betaine in coastal saltmarsh sediments. Microbiome, http://doi.org/10.1186/s40168-019-0732-4.

• E Jameson, J Stephenson, H Jones, A Millard, AK Kaster, KJ Purdy, R Airs, JC Murrell, Y Chen*. Deltaproteobacteria (Pelobacter) and Methanococcides are responsible for choline-dependent methanogenesis in a coastal saltmarsh sediment. ISME Journal,  13, 277–289 (2019).

• Lidbury, I., Kimberley, G., Scanlan, D.J., Murrell, J.C. Chen, Y. (2015) Comparative genomics and mutagenesis analyses of choline metabolism in the marine Roseobacter clade. Environmental Microbiology  17 (12) : 5048–5062.