Presence of auxin indole-3-acetic acid in the northern Adriatic Sea: phytohormones and mucilage

Mazur, H.; Homme, E.

doi:10.3354/meps099163

“…The distribution and functional roles of IAA have been investigated in soil systems (Martens and Frankenberger, 1993b). However, few studies have quantified IAA in seawater (Bentley, 1960;Maruyama et al, 1989;Mazur and Homme, 1993), and these had limited spatial distributions for sampling. The released IAA may function as a signalling molecule or may simply be a waste product.…”

Section: Extracellular Metabolitesmentioning

confidence: 99%

“…The released IAA may function as a signalling molecule or may simply be a waste product. There are several lines of evidence for a connection between the occurrence and concentration of IAA in seawater and mucus exudation by diatoms (Homme and Mazur, 1992;Mazur and Homme, 1993). The production of mucus has broader ecological implications as it can influence the flux of organic matter to the deep ocean (Riebesell et al, 1995;Turk et al, 2010), and the mucus itself consists of a rich matrix of phytoplankton exudates and polysaccharides (Myklestad, 1995;Brussaard et al, 1996).…”

Section: Extracellular Metabolitesmentioning

confidence: 99%

Release of ecologically relevant metabolites by the cyanobacterium Synechococcus elongatus CCMP 1631

Fiore

¹

,

Longnecker

²

,

Soule

³

et al. 2015

Environmental Microbiology

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Photoautotrophic plankton in the surface ocean release organic compounds that fuel secondary production by heterotrophic bacteria. Here we show that an abundant marine cyanobacterium, Synechococcus elongatus, contributes a variety of nitrogen-rich and sulfur-containing compounds to dissolved organic matter. A combination of targeted and untargeted metabolomics and genomic tools was used to characterize the intracellular and extracellular metabolites of S. elongatus. Aromatic compounds such as 4-hydroxybenzoic acid and phenylalanine, as well as nucleosides (e.g., thymidine, 5'-methylthioadenosine, xanthosine), the organosulfur compound 3-mercaptopropionate, and the plant auxin indole 3-acetic acid, were released by S. elongatus at multiple time points during its growth. Further, the amino acid kynurenine was found to accumulate in the media even though it was not present in the predicted metabolome of S. elongatus. This indicates that some metabolites, including those not predicted by an organism's genome, are likely excreted into the environment as waste; however, these molecules may have broader ecological relevance if they are labile to nearby microbes. The compounds described herein provide excellent targets for quantitative analysis in field settings to assess the source and lability of dissolved organic matter in situ.

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“…To date, however, our understanding of the composition of coral reef DOM has been limited by methods that cannot fully resolve the complex nature of DOM, particularly within the low-molecular weight component (LMW DOM, <1,000 Da). This fraction could be particularly important to reef ecosystems as it contains molecules that are produced during metabolism and that may be labile to other organisms (e.g., Mazur & Homme, 1993; Amin et al, 2015). …”

Section: Introductionmentioning

confidence: 99%

Sponge exhalent seawater contains a unique chemical profile of dissolved organic matter

Fiore

¹

,

Freeman

²

,

Kujawinski

³

2017

PeerJ

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Sponges are efficient filter feeders, removing significant portions of particulate and dissolved organic matter (POM, DOM) from the water column. While the assimilation and respiration of POM and DOM by sponges and their abundant microbial symbiont communities have received much attention, there is virtually no information on the impact of sponge holobiont metabolism on the composition of DOM at a molecular-level. We applied untargeted and targeted metabolomics techniques to characterize DOM in seawater samples prior to entering the sponge (inhalant reef water), in samples exiting the sponge (exhalent seawater), and in samples collected just outside the reef area (off reef seawater). Samples were collected from two sponge species, Ircinia campana and Spheciospongia vesparium, on a near-shore hard bottom reef in the Florida Keys. Metabolic profiles generated from untargeted metabolomics analysis indicated that many more compounds were enhanced in the exhalent samples than in the inhalant samples. Targeted metabolomics analysis revealed differences in diversity and concentration of metabolites between exhalent and off reef seawater. For example, most of the nucleosides were enriched in the exhalent seawater, while the aromatic amino acids, caffeine and the nucleoside xanthosine were elevated in the off reef water samples. Although the metabolic profile of the exhalent seawater was unique, the impact of sponge metabolism on the overall reef DOM profile was spatially limited in our study. There were also no significant differences in the metabolic profiles of exhalent water between the two sponge species, potentially indicating that there is a characteristic DOM profile in the exhalent seawater of Caribbean sponges. Additional work is needed to determine whether the impact of sponge DOM is greater in habitats with higher sponge cover and diversity. This work provides the first insight into the molecular-level impact of sponge holobiont metabolism on reef DOM and establishes a foundation for future experimental studies addressing the influence of sponge-derived DOM on chemical and ecological processes in coral reef ecosystems.

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“…To date, however, our understanding of the composition of coral reef DOM has been limited by methods that cannot fully resolve the complex nature of DOM, particularly within the low-molecular weight component (LMW DOM, < 1000 Da). This fraction could be particularly important to reef ecosystems as it contains molecules that are produced during metabolism and that may be labile to other organisms (e.g., Mazur & Homme, 1993;Amin et al, 2015). Sponges are typically considered to be a sink for DOM, releasing exhalent water that has lower concentrations of carbon relative to water entering the sponge (Wilkinson 1987;Yahel et al, 2003;de Goeij et al, 2008b;McMurray et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Peer Review #1 of "Sponge exhalent seawater contains a unique chemical profile of dissolved organic matter (v0.1)"

Aluwihare¹

2017

0

View full text Add to dashboard Cite

Sponges are efficient filter feeders, removing significant portions of particulate and dissolved organic matter (POM, DOM) from the water column. While the assimilation and respiration of POM and DOM by sponges and their abundant microbial symbiont communities have received much attention, there is virtually no information on the impact of sponge holobiont metabolism on the composition of DOM at a molecular-level. We applied untargeted and targeted metabolomics techniques to characterize DOM in seawater samples prior to entering the sponge (inhalant reef water), in samples exiting the sponge (exhalent seawater), and in samples collected just outside the reef area (off reef seawater). Samples were collected from two sponge species, Ircinia campana and Spheciospongia vesparium, on a near-shore hard bottom reef in the Florida Keys. Metabolic profiles generated from untargeted metabolomics analysis indicated that many more compounds were enhanced in the exhalent samples than in the inhalant samples. Targeted metabolomics analysis revealed differences in diversity and concentration of metabolites between exhalent and off reef seawater. For example, most of the nucleosides were enriched in the exhalent seawater, while the aromatic amino acids, caffeine and the nucleoside xanthosine were elevated in the off reef water samples. Although the metabolic profile of the exhalent seawater was unique, the impact of sponge metabolism on the overall reef DOM profile was spatially limited in our study. There were also no significant differences in the metabolic profiles of exhalent water between the two sponge species, potentially indicating that there is a characteristic DOM profile in the exhalent seawater of Caribbean sponges. Additional work is needed to determine whether the impact of sponge DOM is greater in habitats with higher sponge cover and diversity. This work provides the first insight into the molecular-level impact of sponge holobiont metabolism on reef DOM and establishes a foundation for future experimental studies addressing the influence of sponge-derived DOM on chemical and ecological processes in coral reef ecosystems.

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Presence of auxin indole-3-acetic acid in the northern Adriatic Sea: phytohormones and mucilage

Cited by 9 publications

References 8 publications

Release of ecologically relevant metabolites by the cyanobacterium Synechococcus elongatus CCMP 1631

Release of ecologically relevant metabolites by the cyanobacterium Synechococcus elongatus CCMP 1631

Sponge exhalent seawater contains a unique chemical profile of dissolved organic matter

Peer Review #1 of "Sponge exhalent seawater contains a unique chemical profile of dissolved organic matter (v0.1)"

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