Experiments in marine biochemistry. Homarine metabolism in Penaeus duorarum.

Hall, E R; Gurin, Samuel

doi:10.1016/s0021-9258(19)41023-5

Cited by 12 publications

(2 citation statements)

References 13 publications

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“…Homarine and trigonelline are structural isomers made by different biosynthetic pathways that both involve SAM‐dependent methyltransferases (Hall and Gurin, 1975; Ashihara, 2008). The 13 C 1 isotopologue of trigonelline increased in both experiments, with a greater increase in the south than in the north (Fig.…”

Section: Resultsmentioning

confidence: 99%

Glycine betaine uptake and metabolism in marine microbial communities

Boysen

Durham

Kumler

et al. 2022

Environmental Microbiology

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Summary Glycine betaine (GBT) is a compatible solute in high concentrations in marine microorganisms. As a component of labile organic matter, GBT has complex biochemical potential as a substrate for microbial use that is unconstrained in the environment. Here we determine the uptake kinetics and metabolic fate of GBT in two natural microbial communities in the North Pacific characterized by different nitrate concentrations. Dissolved GBT had maximum uptake rates of 0.36 and 0.56 nM h−1 with half‐saturation constants of 79 and 11 nM in the high nitrate and low nitrate stations respectively. During multiday incubations, most GBT taken into cells was retained as a compatible solute. Stable isotopes derived from the added GBT were also observed in other metabolites, including choline, carnitine and sarcosine, suggesting that GBT was used for biosynthesis and for catabolism to pyruvate and ammonium. Where nitrate was scarce, GBT was primarily metabolized via demethylation to glycine. Gene transcript data were consistent with SAR11 using GBT as a source of methyl groups to fuel the methionine cycle. Where nitrate concentrations were higher, more GBT was partitioned for lipid biosynthesis by both bacteria and eukaryotic phytoplankton. Our data highlight unexpected metabolic pathways and potential routes of microbial metabolite exchange.

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Section: Resultsmentioning

confidence: 99%

Glycine betaine uptake and metabolism in marine microbial communities

Boysen

Durham

Kumler

et al. 2022

Environmental Microbiology

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“…Biochemically, the sources and sinks for homarine and trigonelline are likely distinct. Trigonelline is produced from nicotinic acid ( 47 ), while homarine is decarboxylated from quinolinic acid, which is produced from tryptophan ( 48 ), though the exact enzyme that performs the decarboxylation has not been characterized. The first step of bacterial trigonelline degradation is the opening of the aromatic ring by the TgnA/TgnB oxygenase system ( 40 ).…”

Section: Resultsmentioning

confidence: 99%

Marine Community Metabolomes Carry Fingerprints of Phytoplankton Community Composition

et al. 2021

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Phytoplankton transform inorganic carbon into thousands of biomolecules that represent an important pool of fixed carbon, nitrogen, and sulfur in the surface ocean. Metabolite production differs between phytoplankton, and the flux of these molecules through the microbial food web depends on compound-specific bioavailability to members of a wider microbial community. Yet relatively little is known about the diversity or concentration of metabolites within marine plankton. Here, we compare 313 polar metabolites in 21 cultured phytoplankton species and in natural planktonic communities across environmental gradients to show that bulk community metabolomes reflect the chemical composition of the phytoplankton community. We also show that groups of compounds have similar patterns across space and taxonomy, suggesting that the concentrations of these compounds in the environment are controlled by similar sources and sinks. We quantify several compounds in the surface ocean that represent substantial understudied pools of labile carbon. For example, the N-containing metabolite homarine was up to 3% of particulate carbon and is produced in high concentrations by cultured Synechococcus, and S-containing gonyol accumulated up to 2.5 nM in surface particles and likely originates from dinoflagellates or haptophytes. Our results show that phytoplankton composition directly shapes the carbon composition of the surface ocean. Our findings suggest that in order to access these pools of bioavailable carbon, the wider microbial community must be adapted to phytoplankton community composition. IMPORTANCE Microscopic phytoplankton transform 100 million tons of inorganic carbon into thousands of different organic compounds each day. The structure of each chemical is critical to its biological and ecosystem function, yet the diversity of biomolecules produced by marine microbial communities remained mainly unexplored, especially small polar molecules which are often considered the currency of the microbial loop. Here, we explore the abundance and diversity of small biomolecules in planktonic communities across ecological gradients in the North Pacific and within 21 cultured phytoplankton species. Our work demonstrates that phytoplankton diversity is an important determinant of the chemical composition of the highly bioavailable pool of organic carbon in the ocean, and we highlight understudied yet abundant compounds in both the environment and cultured organisms. These findings add to understanding of how the chemical makeup of phytoplankton shapes marine microbial communities where the ability to sense and use biomolecules depends on the chemical structure.

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Nitrogen Metabolism

Claybrook¹

1983

Internal Anatomy and Physiological Regulation

101

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Experiments in marine biochemistry. Homarine metabolism in Penaeus duorarum.

Cited by 12 publications

References 13 publications

Glycine betaine uptake and metabolism in marine microbial communities

Glycine betaine uptake and metabolism in marine microbial communities

Marine Community Metabolomes Carry Fingerprints of Phytoplankton Community Composition

Nitrogen Metabolism

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