Uptake of Prochlorococcus-derived metabolites by Alteromonas macleodii MIT1002 shows high levels of substrate specificity

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 11, 2025

Abstract Seawater contains an abundance of small biomolecules, or metabolites, that are highly labile components dissolved organic matter (DOM). Marine microbes interact by exchanging thus shaping marine microbial ecology, DOM composition, and global carbon cycling. To better constrain one set microbe-metabolite interactions, we cultured the gammaproteobacterium Alteromonas macleodii MIT1002 on a range compounds excreted sympatric cyanobacterium, Prochlorococcus . could assimilate branched chain amino acids leucine, isoleucine, valine, as well 3-methyl-2-oxobutanoic acid (a ketoacid intermediate valine metabolism), but not thymidine, kynurenine, 4-hydroxybenzoic acid, other ketoacids. The assimilation indicates can metabolically process each corresponding ketoacid, suggesting transporter specificity underlies observed substrate for acid. These experiments show even subtle changes in chemical structure result different interactions fates metabolites. Significance Statement Microbial with important controls cycle. Dissolved is often considered bulk, which leaves nature these poorly constrained. Here microbe-molecule be specific, distinguishing between molecules structurally biochemically similar. This implies this pool have large impacts overall system function, measuring molecular-level resolution to characterizing interactions. We further explore mechanism underlying suggest it caused selectivity, meaning ability selectively uptake specific molecules.

Language: Английский

---

New chemical and microbial perspectives on vitamin B1 and vitamer dynamics of a coastal system

ISME Communications, Journal Year: 2024, Volume and Issue: 4(1)

Published: Jan. 1, 2024

Abstract Vitamin B1 (thiamin, B1) is an essential micronutrient for cells, yet intriguingly in aquatic systems most bacterioplankton are unable to synthesize it de novo (auxotrophy), requiring exogenous source. Cycling of this valuable metabolite has not been fully investigated and vitamers (B1-related compounds) have only begun be measured incorporated into the cycle. Here, we identify potential key producers consumers gain new insights dynamics cycling through measurements (HMP: 4-amino-5-hydroxymethyl-2-methylpyrimidine, HET: 4-methyl-5-thiazoleethanol, FAMP: N-formyl-4-amino-5-aminomethyl-2-methylpyrimidine) particulate dissolved pool a temperate coastal system. Dissolved was primary limiting nutrient bacterial production relatively stable across seasons with concentrations ranging from 74–117 pM, indicating balance supply demand. However, vitamer concentration changed markedly season as did transcripts related salvage transport suggesting use by certain bacterioplankton, e.g. Pelagibacterales. Genomic transcriptomic analyses showed that up 78% taxa were auxotrophs. Notably, restricted few abundant (e.g. Vulcanococcus, BACL14 (Burkholderiales), Verrucomicrobiales) seasons. In summer, picocyanobacteria important putative sources, based on transcriptional activity, leading increase pool. Our results provide dynamic view players processes involved over time waters, specific priority populations future study.

Language: Английский

---

Seasonal patterns in b-vitamins and cobalamin co-limitation in the Northwest Atlantic

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 10, 2024

Abstract B-vitamins are important co-enzymes that have long been hypothesized to play key roles in marine ecosystems. However, environmental measurements remain scarce, which limits our understanding of their potential impact. Here, we present mass spectrometry-based b-vitamins (B 1 , B 2 3 5 6, 12 ) and related vitamers along a transect the Northwest Atlantic Ocean, both particulate phase dissolved seawater, seasonally over years, couple this with targeted investigations impact (cobalamin) on phytoplankton growth. We show these metabolites at femto pico-molar concentrations demonstrate season explains most variance but not dissolved, offering further evidence metabolite inventories two phases often decoupled. find correlations between organic carbon chlorophyll DMB fall spring, indicating unique seasonal drivers vitamin inventories. Of all measured vitamins, only cobalamin was enriched phase, predominantly spring. documented nitrogen co-limitation growth during spring bloom decline, when is seemingly drawn down, fall, elevated. These differences may be underpinned by increased importance remodeling recycling fall. This study provides insights into absolute concentrations, stoichiometry, variability ocean offers exerts seasonally-varying controls

Language: Английский

---

Polyelectrolyte mannan from diatoms reshapes sunlit ocean microbiome

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: July 5, 2024

Abstract Algae catalyze half of the global solar powered reduction carbon dioxide to organic molecules. While this synthesis shapes genomes heterotrophic microbiota globally, many corresponding structures remain elusive. We show that diatoms release a mannan polyelectrolyte selecting for bacteria with specifically adapted enzymatic cascade. NMR spectroscopy, chromatography, automated glycan assembly and dissection resolved structure C6 sulfated α-1,3-mannan exceptional simplicity polysaccharide from algae. Biochemical, physiological structural analyses demonstrated some can hydrolyze cascade just four enzymes. Circumnavigation metagenome data revealed genes in Atlantic, Pacific, Southern Indian Ocean surface waters. may exert substantial selection pressure on marine around globe.

Language: Английский

---

A witches’ brew: Dissolved metabolites in seawater

Elsevier eBooks, Journal Year: 2024, Volume and Issue: unknown, P. 69 - 99

Published: Jan. 1, 2024

Language: Английский

---