Two decades of bacterial ecology and evolution in a freshwater lake

Nature Microbiology, Journal Year: 2025, Volume and Issue: 10(1), P. 246 - 257

Published: Jan. 3, 2025

Language: Английский

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Bacterial alginate metabolism: an important pathway for bioconversion of brown algae

Biotechnology for Biofuels, Journal Year: 2021, Volume and Issue: 14(1)

Published: July 18, 2021

Abstract Brown macroalgae have attracted great attention as an alternative feedstock for biorefining. Although direct conversion of ethanol from alginates (major components brown cell walls) is not amenable industrial production, significant progress has been made only on enzymes involved in alginate degradation, but also metabolic pathways biorefining at the laboratory level. In this article, we summarise recent advances four aspects: alginate, lyases, different alginate-degrading systems, and application lyases associated pathways. This knowledge will likely inspire sustainable solutions further both their

Language: Английский

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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

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Petrobactin, a siderophore produced by Alteromonas, mediates community iron acquisition in the global ocean

The ISME Journal, Journal Year: 2021, Volume and Issue: 16(2), P. 358 - 369

Published: Aug. 2, 2021

Abstract It is now widely accepted that siderophores play a role in marine iron biogeochemical cycling. However, the mechanisms by which affect availability of from specific sources and resulting significance these processes on cycling as whole have remained largely untested. In this study, we develop model system for testing effects siderophore production bioavailability using copiotroph Alteromonas macleodii ATCC 27126. Through generation knockout cell line ΔasbB::kmr, lacks biosynthetic capabilities, demonstrate petrobactin enables acquisition mineral weaker iron-ligand complexes. Notably, utilization lithogenic iron, such atmospheric dust, indicates significant incorporation new into systems. We also detected petrobactin, photoreactive siderophore, directly seawater mid-latitudes North Pacific identified pathway bacterial metagenome-assembled genomes distributed across global ocean. Together, results improve our mechanistic understanding environment wherein speciation, bioavailability, residence time can be influenced microbial activities.

Language: Английский

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Assessing the Plastisphere from Floating Plastics in the Northwestern Mediterranean Sea, with Emphasis on Viruses

Microorganisms, Journal Year: 2024, Volume and Issue: 12(3), P. 444 - 444

Published: Feb. 22, 2024

Plastics in the ocean create "plastisphere", a diverse habitat hosting various life forms. Other than pollution induced by plastics, co-occurrence of primary producers, symbiotic organisms, decomposers, and pathogens within plastisphere raises questions about how they influence dynamics marine ecosystems. Here, we used shotgun DNA-sequencing approach to describe species thriving on floating plastics collected two Mediterranean sites. Our findings revealed many bacteria, eukaryotes, viruses, archaea each plastic. Proteobacteria was dominant (70% reads entire dataset), with other groups such as Ascomycota fungi (11%) Bacteroidetes (9%) also being represented. The community structure not affected polymeric composition or plastic shape. Notably, pathogenic Vibrio species, including V. campbelli, alginolyticus, coralliilyticus, were among most abundant species. Viruses, despite showing lower relative abundances, occurred all samples, especially Herpesvirales, Caudovirales, Poxviridae groups. A significant finding presence White Spot Syndrome virus (WSSV). This pathogen, responsible for devastating outbreaks aquaculture systems, had been previously reported plastisphere. study emphasizes need further investigation into ecological economic impacts organisms ocean.

Language: Английский

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Linkages Among Dissolved Organic Matter Export, Dissolved Metabolites, and Associated Microbial Community Structure Response in the Northwestern Sargasso Sea on a Seasonal Scale

Frontiers in Microbiology, Journal Year: 2022, Volume and Issue: 13

Published: March 8, 2022

Deep convective mixing of dissolved and suspended organic matter from the surface to depth can represent an important export pathway biological carbon pump. The seasonally oligotrophic Sargasso Sea experiences annual winter as deep 300 m, providing a unique model system examine (DOM) its subsequent compositional transformation by microbial oxidation. We analyzed biogeochemical parameters collected northwestern Sea, including bulk (DOC), total amino acids (TDAA), metabolites, bacterial abundance production, community structure, assess fate DOM microbes on seasonal time-scale in 2016–2017. dynamics at Bermuda Atlantic Time-series Study site followed general trend DOC accumulation during stratified periods downward flux mixing. Changes acid concentrations compositions provide useful indices diagenetic alteration DOM. TDAA degradation increased mesopelagic zone mixing, indicating relatively less diagenetically altered (i.e., more labile) During subset such acids, vitamins, benzoic was produced or lost. change were accompanied growth response specific lineages SAR11, SAR202, SAR86 clades, Acidimicrobiales , Flavobacteria shortly following Complementary biogeochemistry measurements revealed changes composition state, highlighting quantity quality ocean.

Language: Английский

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Labile Dissolved Organic Matter Compound Characteristics Select for Divergence in Marine Bacterial Activity and Transcription

Frontiers in Microbiology, Journal Year: 2020, Volume and Issue: 11

Published: Sept. 25, 2020

Bacteria play a key role in the oceanic carbon cycle partly because they rapidly assimilate labile dissolved organic matter (DOM). However, knowledge of molecular mechanisms at work when bacterioplankton metabolize DOM is still limited. We conducted seawater culture enrichment experiments with ecologically relevant polymer and monomer model compounds for compound classes carbohydrates (polysaccharides versus monosaccharides), proteins (polypeptides amino acids) nucleic acids (DNA nucleotides). noted pronounced changes bacterial growth, activity, transcription related to characteristics. Transcriptional responses differed between classes, showing "core gene" (notably genes utilization, glucosidases, motility chemotaxis), (e.g. phosphorus metabolism genes), DNA conversion, nucleotides TonB transporters). Moreover, there was strong divergence functional level particular monomers polymers mediated by distinct taxa primarily protein classes. These specific included membrane transporters (Oceanospirillales; monosaccharides treatment), glycogen utilization (Alteromonadales; polysaccharides), uptake systems polyamines (Pseudomonadales; acids), transferases (Flavobacteriales; polypeptides). Responses were limited both dominated Alteromonadales. Altogether, our findings show that two important facets DOM, class condensation state, shape gene expression, ultimately select (functional) groups. emphasize interdependency marine bacteria regulating transformation surface waters thereby determining central planetary cycle.

Language: Английский

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Microbial diversity of co-occurring heterotrophs in cultures of marine picocyanobacteria

Environmental Microbiome, Journal Year: 2021, Volume and Issue: 16(1)

Published: Jan. 6, 2021

Abstract Background The cyanobacteria Prochlorococcus and Synechococcus are responsible for around 10% of global net primary productivity, serving as part the foundation marine food webs. Heterotrophic bacteria often co-isolated with these picocyanobacteria in seawater enrichment cultures that contain no added organic carbon; heterotrophs grow on carbon supplied by photolithoautotrophs. For examining selective pressures shaping autotroph/heterotroph interactions, we have made use unialgal maintained hundreds to thousands generations lab. We examine diversity 74 obtained from diverse areas oceans. Results Heterotroph community composition differed between clades ecotypes autotrophic ‘hosts’ but there was significant overlap heterotroph across cultures. Collectively, were comprised many shared taxa, even at genus level. Yet, observed differences associated time since isolation, location, depth, methods isolation. majority rare ocean, conditions favor opportunistic outgrowth bacteria. However, found a few examples, such family Rhodobacteraceae, ubiquitous abundant their abundance wild is also positively correlated picocyanobacteria. Conclusions Particular surrounding isolation persistent effect long-term culture composition, likely bottlenecking selection happen during early stages highlight potential ecologically relevant relationships identifying patterns distribution culture-enriched organisms

Language: Английский

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Unveiling the P-solubilizing potential of bacteria enriched from natural colonies of Red Sea Trichodesmium spp.

The Science of The Total Environment, Journal Year: 2025, Volume and Issue: 963, P. 178446 - 178446

Published: Jan. 17, 2025

Language: Английский

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Strong Effects of Increased Hydrostatic Pressure on Polysaccharide‐Hydrolyzing Enzyme Activities in Coastal Seawater and Sediments

Journal of Geophysical Research Biogeosciences, Journal Year: 2025, Volume and Issue: 130(2)

Published: Feb. 1, 2025

Abstract Heterotrophic microorganisms are responsible for transforming and respiring a substantial fraction of the organic matter produced by phytoplankton in surface ocean. Much this is composed polysaccharides, high‐molecular weight (HMW) sugars. To initiate degradation must produce extracellular enzymes right structural specificity to hydrolyze these complex structures. date, most measurements enzyme activities made at situ temperatures, but atmospheric pressure. However, previous studies have shown that hydrostatic pressure can impact functionality enzymes. Since deep sea communities may be seeded microbes from shallow waters, we aimed determine if affects performance coastal waters. extent which enzymatic microbial affected pressure, quantified seven polysaccharides under pressures ranging 0.1 MPa (atmospheric) 40 (equivalent 4,000 m). Enzyme pelagic were inhibited with increased while benthic more resistant Addition HMW resulted freely‐dissolved (<0.2 μm) strongly suggesting pressure‐resistant cell‐surface attached. Because inhibition varied polysaccharide, surmise complexity polysaccharide—and therefore number distinct required hydrolysis—is likely closely associated inhibition.

Language: Английский

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