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Klimek D, Herold M, Calusinska M. Comparative genomic analysis of Planctomycetota potential for polysaccharide degradation identifies biotechnologically relevant microbes. BMC Genomics 2024; 25:523. [PMID: 38802741 PMCID: PMC11131199 DOI: 10.1186/s12864-024-10413-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 05/15/2024] [Indexed: 05/29/2024] Open
Abstract
BACKGROUND Members of the Planctomycetota phylum harbour an outstanding potential for carbohydrate degradation given the abundance and diversity of carbohydrate-active enzymes (CAZymes) encoded in their genomes. However, mainly members of the Planctomycetia class have been characterised up to now, and little is known about the degrading capacities of the other Planctomycetota. Here, we present a comprehensive comparative analysis of all available planctomycetotal genome representatives and detail encoded carbohydrolytic potential across phylogenetic groups and different habitats. RESULTS Our in-depth characterisation of the available planctomycetotal genomic resources increases our knowledge of the carbohydrolytic capacities of Planctomycetota. We show that this single phylum encompasses a wide variety of the currently known CAZyme diversity assigned to glycoside hydrolase families and that many members encode a versatile enzymatic machinery towards complex carbohydrate degradation, including lignocellulose. We highlight members of the Isosphaerales, Pirellulales, Sedimentisphaerales and Tepidisphaerales orders as having the highest encoded hydrolytic potential of the Planctomycetota. Furthermore, members of a yet uncultivated group affiliated to the Phycisphaerales order could represent an interesting source of novel lytic polysaccharide monooxygenases to boost lignocellulose degradation. Surprisingly, many Planctomycetota from anaerobic digestion reactors encode CAZymes targeting algal polysaccharides - this opens new perspectives for algal biomass valorisation in biogas processes. CONCLUSIONS Our study provides a new perspective on planctomycetotal carbohydrolytic potential, highlighting distinct phylogenetic groups which could provide a wealth of diverse, potentially novel CAZymes of industrial interest.
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Affiliation(s)
- Dominika Klimek
- Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology (LIST), 41 rue du Brill, Belvaux, L-4422, Luxembourg.
- The Faculty of Science, Technology and Medicine (FSTM), University of Luxembourg, 2 Avenue de l'Université, Esch-sur-Alzette, L-4365, Luxembourg.
| | - Malte Herold
- Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology (LIST), 41 rue du Brill, Belvaux, L-4422, Luxembourg
| | - Magdalena Calusinska
- Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology (LIST), 41 rue du Brill, Belvaux, L-4422, Luxembourg
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2
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Zhao Z, Amano C, Reinthaler T, Orellana MV, Herndl GJ. Substrate uptake patterns shape niche separation in marine prokaryotic microbiome. SCIENCE ADVANCES 2024; 10:eadn5143. [PMID: 38748788 PMCID: PMC11095472 DOI: 10.1126/sciadv.adn5143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 04/11/2024] [Indexed: 05/19/2024]
Abstract
Marine heterotrophic prokaryotes primarily take up ambient substrates using transporters. The patterns of transporters targeting particular substrates shape the ecological role of heterotrophic prokaryotes in marine organic matter cycles. Here, we report a size-fractionated pattern in the expression of prokaryotic transporters throughout the oceanic water column due to taxonomic variations, revealed by a multi-"omics" approach targeting ATP-binding cassette (ABC) transporters and TonB-dependent transporters (TBDTs). Substrate specificity analyses showed that marine SAR11, Rhodobacterales, and Oceanospirillales use ABC transporters to take up organic nitrogenous compounds in the free-living fraction, while Alteromonadales, Bacteroidetes, and Sphingomonadales use TBDTs for carbon-rich organic matter and metal chelates on particles. The expression of transporter proteins also supports distinct lifestyles of deep-sea prokaryotes. Our results suggest that transporter divergency in organic matter assimilation reflects a pronounced niche separation in the prokaryote-mediated organic matter cycles.
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Affiliation(s)
- Zihao Zhao
- Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Djerassiplatz 1, A-1030 Vienna, Austria
| | - Chie Amano
- Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Djerassiplatz 1, A-1030 Vienna, Austria
| | - Thomas Reinthaler
- Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Djerassiplatz 1, A-1030 Vienna, Austria
| | - Mónica V. Orellana
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98195, USA
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Gerhard J. Herndl
- Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Djerassiplatz 1, A-1030 Vienna, Austria
- NIOZ, Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, Den Burg, Netherlands
- Environmental and Climate Research Hub, University of Vienna, Althanstraße 14, A-1090 Vienna, Austria
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3
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Zhao Z, Baltar F, Herndl GJ. Decoupling between the genetic potential and the metabolic regulation and expression in microbial organic matter cleavage across microbiomes. Microbiol Spectr 2024; 12:e0303623. [PMID: 38511953 DOI: 10.1128/spectrum.03036-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 03/06/2024] [Indexed: 03/22/2024] Open
Abstract
Metagenomics, metatranscriptomics, and metaproteomics are used to explore the microbial capability of enzyme secretion, but the links between protein-encoding genes and corresponding transcripts/proteins across ecosystems are underexplored. By conducting a multi-omics comparison focusing on key enzymes (carbohydrate-active enzymes [CAZymes] and peptidases) cleaving the main biomolecules across distinct microbiomes living in the ocean, soil, and human gut, we show that the community structure, functional diversity, and secretion mechanisms of microbial secretory CAZymes and peptidases vary drastically between microbiomes at metagenomic, metatranscriptomic, and metaproteomic levels. Such variations lead to decoupled relationships between CAZymes and peptidases from genetic potentials to protein expressions due to the different responses of key players toward organic matter sources and concentrations. Our results highlight the need for systematic analysis of the factors shaping patterns of microbial cleavage on organic matter to better link omics data to ecosystem processes. IMPORTANCE Omics tools are used to explore adaptive mechanism of microbes in diverse systems, but the advantages and limitations of different omics tools remain skeptical. Here, we reported distinct profiles in microbial secretory enzyme composition revealed by different omics methods. In general, the predicted function from metagenomic analysis decoupled from the expression of corresponding transcripts/proteins. Linking omics results to taxonomic origin, functional capability, substrate specificity, secretion preference, and enzymatic activity measurement suggested the substrate's source, concentration and stoichiometry impose strong filtering on the expression of extracellular enzymes, which may overwrite the genetic potentials. Our results present an integrated perspective on the need for multi-dimensional characterization of microbial adaptation in a changing environment.
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Affiliation(s)
- Zihao Zhao
- Department of Functional and Evolutionary Ecology, Bio-Oceanography Unit, University of Vienna, Vienna, Austria
| | - Federico Baltar
- Department of Functional and Evolutionary Ecology, Bio-Oceanography Unit, University of Vienna, Vienna, Austria
| | - Gerhard J Herndl
- Department of Functional and Evolutionary Ecology, Bio-Oceanography Unit, University of Vienna, Vienna, Austria
- NIOZ, Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, Den Burg, the Netherlands
- Vienna Metabolomics Center, University of Vienna, Vienna, Austria
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Bradshaw C, Iburg S, Morys C, Sköld M, Pusceddu A, Ennas C, Jonsson P, Nascimento FJA. Effects of bottom trawling and environmental factors on benthic bacteria, meiofauna and macrofauna communities and benthic ecosystem processes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171076. [PMID: 38382611 DOI: 10.1016/j.scitotenv.2024.171076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 02/01/2024] [Accepted: 02/16/2024] [Indexed: 02/23/2024]
Abstract
Soft sediment marine benthic ecosystems comprise a diverse community of bacteria, meiofauna and macrofauna, which together support a range of ecosystem processes such as biogeochemical cycling. These ecosystems are also fishing grounds for demersal species that are often caught using bottom trawling. This fishing method can have deleterious effects on benthic communities by causing injury or mortality, and through alteration of sediment properties that in turn influence community structure. Although the impacts of bottom trawling on macrofauna are relatively well studied, less is known about the responses of meiofauna and bacteria to such disturbances, or how bottom trawling impacts benthic ecosystem processes. Quantifying trawling impacts against a background of natural environmental variability is also a challenge. To address these questions, we examined effects of bottom trawling and a range of environmental variables (e.g. water chemistry and physical and biochemical surface sediment properties) on a) bacterial, meiofaunal and macrofaunal community structure and b) benthic ecosystem processes (nutrient fluxes, extracellular enzyme activities and carbon turnover and degradation rates). We also investigated the link between the benthic macrofauna community and the same ecosystem processes. While there was a significant effect of bottom trawling intensity on macrofaunal community structure, the same was not seen for bacterial or meiofaunal community composition, which were more affected by environmental factors, such as surface sediment properties. The labile component of the surface sediment carbon pool was higher at highly trawled sites. Carbon degradation rates, extracellular enzyme activities, oxygen fluxes and some nutrient fluxes were significantly affected by trawling, but ecosystem processes were also strongly linked to the abundance of key bioturbators (Macoma balthica, Halicryptus spinulosus, Scoloplos armiger and Pontoporeia femorata). Although benthic ecosystems were affected by a combination of trawling and natural variability, disentangling these showed that the anthropogenic effects were clearest on the larger component of the community, i.e. macrofauna composition, and on ecosystem processes related to sedimentary carbon.
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Affiliation(s)
- Clare Bradshaw
- Stockholm University, Department of Ecology, Environment and Plant Sciences, Stockholm, Sweden.
| | - Sven Iburg
- Stockholm University, Department of Ecology, Environment and Plant Sciences, Stockholm, Sweden
| | - Claudia Morys
- Stockholm University, Department of Ecology, Environment and Plant Sciences, Stockholm, Sweden
| | - Mattias Sköld
- Department of Aquatic Resources, Institute of Marine Research, Swedish University of Agricultural Sciences, Lysekil, Sweden
| | - Antonio Pusceddu
- University of Cagliari, Department of Life and Environmental Sciences, Cagliari, Sardinia, Italy
| | - Claudia Ennas
- University of Cagliari, Department of Life and Environmental Sciences, Cagliari, Sardinia, Italy
| | - Patrik Jonsson
- Department of Aquatic Resources, Institute of Marine Research, Swedish University of Agricultural Sciences, Lysekil, Sweden
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Maldonado-Ruiz K, Pedroza-Islas R, Pedraza-Segura L. Blue Biotechnology: Marine Bacteria Bioproducts. Microorganisms 2024; 12:697. [PMID: 38674641 PMCID: PMC11051736 DOI: 10.3390/microorganisms12040697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 03/19/2024] [Accepted: 03/20/2024] [Indexed: 04/28/2024] Open
Abstract
The ocean is the habitat of a great number of organisms with different characteristics. Compared to terrestrial microorganisms, marine microorganisms also represent a vast and largely unexplored reservoir of bioactive compounds with diverse industrial applications like terrestrial microorganisms. This review examines the properties and potential applications of products derived from marine microorganisms, including bacteriocins, enzymes, exopolysaccharides, and pigments, juxtaposing them in some cases against their terrestrial counterparts. We discuss the distinct characteristics that set marine-derived products apart, including enhanced stability and unique structural features such as the amount of uronic acid and sulfate groups in exopolysaccharides. Further, we explore the uses of these marine-derived compounds across various industries, ranging from food and pharmaceuticals to cosmetics and biotechnology. This review also presents a broad description of biotechnologically important compounds produced by bacteria isolated from marine environments, some of them with different qualities compared to their terrestrial counterparts.
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Affiliation(s)
| | - Ruth Pedroza-Islas
- Department of Chemical, Industrial and Food Engineering, Universidad Iberoamericana, Prol. Paseo de la Reforma 880, Lomas de Santa Fe, Mexico City 01210, Mexico; (K.M.-R.); (L.P.-S.)
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Jiao N, Luo T, Chen Q, Zhao Z, Xiao X, Liu J, Jian Z, Xie S, Thomas H, Herndl GJ, Benner R, Gonsior M, Chen F, Cai WJ, Robinson C. The microbial carbon pump and climate change. Nat Rev Microbiol 2024:10.1038/s41579-024-01018-0. [PMID: 38491185 DOI: 10.1038/s41579-024-01018-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2024] [Indexed: 03/18/2024]
Abstract
The ocean has been a regulator of climate change throughout the history of Earth. One key mechanism is the mediation of the carbon reservoir by refractory dissolved organic carbon (RDOC), which can either be stored in the water column for centuries or released back into the atmosphere as CO2 depending on the conditions. The RDOC is produced through a myriad of microbial metabolic and ecological processes known as the microbial carbon pump (MCP). Here, we review recent research advances in processes related to the MCP, including the distribution patterns and molecular composition of RDOC, links between the complexity of RDOC compounds and microbial diversity, MCP-driven carbon cycles across time and space, and responses of the MCP to a changing climate. We identify knowledge gaps and future research directions in the role of the MCP, particularly as a key component in integrated approaches combining the mechanisms of the biological and abiotic carbon pumps for ocean negative carbon emissions.
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Affiliation(s)
- Nianzhi Jiao
- Innovation Research Center for Carbon Neutralization, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, China.
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China.
| | - Tingwei Luo
- Innovation Research Center for Carbon Neutralization, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, China
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
| | - Quanrui Chen
- Innovation Research Center for Carbon Neutralization, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, China
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
| | - Zhao Zhao
- Innovation Research Center for Carbon Neutralization, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, China
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
| | - Xilin Xiao
- Innovation Research Center for Carbon Neutralization, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, China
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
| | - Jihua Liu
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
- Institute of Marine Science and Technology, Shandong University, Qingdao, China
| | - Zhimin Jian
- State Key Laboratory of Marine Geology, Tongji University, Shanghai, China
| | - Shucheng Xie
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Helmuth Thomas
- Institute of Carbon Cycles, Helmholtz-Zentrum Hereon, Geesthacht, Germany
- Institut für Chemie und Biologie des Meeres (ICBM), Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Gerhard J Herndl
- Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
| | - Ronald Benner
- Department of Biological Sciences, School of the Earth, Ocean and Environment, University of South Carolina, Columbia, SC, USA
| | - Micheal Gonsior
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
- Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, MD, USA
| | - Feng Chen
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, MD, USA
| | - Wei-Jun Cai
- School of Marine Science and Policy, University of Delaware, Newark, DE, USA
| | - Carol Robinson
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China.
- Centre for Ocean and Atmospheric Sciences (COAS), School of Environmental Sciences, University of East Anglia, Norwich, UK.
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Wright LS, Simpkins T, Filbee-Dexter K, Wernberg T. Temperature sensitivity of detrital photosynthesis. ANNALS OF BOTANY 2024; 133:17-28. [PMID: 38142363 PMCID: PMC10921823 DOI: 10.1093/aob/mcad167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/24/2023] [Accepted: 11/22/2023] [Indexed: 12/25/2023]
Abstract
BACKGROUND AND AIMS Kelp forests are increasingly considered blue carbon habitats for ocean-based biological carbon dioxide removal, but knowledge gaps remain in our understanding of their carbon cycle. Of particular interest is the remineralization of detritus, which can remain photosynthetically active. Here, we study a widespread, thermotolerant kelp (Ecklonia radiata) to explore detrital photosynthesis as a mechanism underlying temperature and light as two key drivers of remineralization. METHODS We used meta-analysis to constrain the thermal optimum (Topt) of E. radiata. Temperature and light were subsequently controlled over a 119-day ex situ decomposition experiment. Flow-through experimental tanks were kept in darkness at 15 °C or under a subcompensating maximal irradiance of 8 µmol photons m-2 s-1 at 15, 20 or 25 °C. Photosynthesis of laterals (analogues to leaves) was estimated using closed-chamber oxygen evolution in darkness and under a saturating irradiance of 420 µmol photons m-2 s-1. KEY RESULTS T opt of E. radiata is 18 °C across performance variables (photosynthesis, growth, abundance, size, mass and fertility), life stages (gametophyte and sporophyte) and populations. Our models predict that a temperature of >15 °C reduces the potential for E. radiata detritus to be photosynthetically viable, hence detrital Topt ≤ 15 °C. Detritus is viable under subcompensating irradiance, where it performs better than in darkness. Comparison of net and gross photosynthesis indicates that elevated temperature primarily decreases detrital photosynthesis, whereas darkness primarily increases detrital respiration compared with optimal experimental conditions, in which detrital photosynthesis can persist for ≥119 days. CONCLUSIONS T opt of kelp detritus is ≥3 °C colder than that of the intact plant. Given that E. radiata is one of the most temperature-tolerant kelps, this suggests that photosynthesis is generally more thermosensitive in the detrital phase, which partly explains the enhancing effect of temperature on remineralization. In contrast to darkness, even subcompensating irradiance maintains detrital viability, elucidating the accelerating effect of depth and its concomitant light reduction on remineralization to some extent. Detrital photosynthesis is a meaningful mechanism underlying at least two drivers of remineralization, even below the photoenvironment inhabited by the attached alga.
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Affiliation(s)
- Luka Seamus Wright
- Oceans Institute, University of Western Australia, Perth,Australia
- School of Biological Sciences, University of Western Australia, Perth,Australia
| | - Taylor Simpkins
- Oceans Institute, University of Western Australia, Perth,Australia
- School of Biological Sciences, University of Western Australia, Perth,Australia
| | - Karen Filbee-Dexter
- Oceans Institute, University of Western Australia, Perth,Australia
- School of Biological Sciences, University of Western Australia, Perth,Australia
- Institute of Marine Research, His, Norway
| | - Thomas Wernberg
- Oceans Institute, University of Western Australia, Perth,Australia
- School of Biological Sciences, University of Western Australia, Perth,Australia
- Institute of Marine Research, His, Norway
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Balmonte JP, Giebel HA, Arnosti C, Simon M, Wietz M. Distinct bacterial succession and functional response to alginate in the South, Equatorial, and North Pacific Ocean. Environ Microbiol 2024; 26:e16594. [PMID: 38418376 DOI: 10.1111/1462-2920.16594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 01/26/2024] [Indexed: 03/01/2024]
Abstract
The availability of alginate, an abundant macroalgal polysaccharide, induces compositional and functional responses among marine microbes, but these dynamics have not been characterized across the Pacific Ocean. We investigated alginate-induced compositional and functional shifts (e.g., heterotrophic production, glucose turnover, hydrolytic enzyme activities) of microbial communities in the South Subtropical, Equatorial, and Polar Frontal North Pacific in mesocosms. We observed that shifts in response to alginate were site-specific. In the South Subtropical Pacific, prokaryotic cell counts, glucose turnover, and peptidase activities changed the most with alginate addition, along with the enrichment of the widest range of particle-associated taxa (161 amplicon sequence variants; ASVs) belonging to Alteromonadaceae, Rhodobacteraceae, Phormidiaceae, and Pseudoalteromonadaceae. Some of these taxa were detected at other sites but only enriched in the South Pacific. In the Equatorial Pacific, glucose turnover and heterotrophic prokaryotic production increased most rapidly; a single Alteromonas taxon dominated (60% of the community) but remained low (<2%) elsewhere. In the North Pacific, the particle-associated community response to alginate was gradual, with a more limited range of alginate-enriched taxa (82 ASVs). Thus, alginate-related ecological and biogeochemical shifts depend on a combination of factors that include the ability to utilize alginate, environmental conditions, and microbial interactions.
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Affiliation(s)
- John Paul Balmonte
- Department of Earth, Marine and Environmental Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, PA, USA
| | - Helge-Ansgar Giebel
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
| | - Carol Arnosti
- Department of Earth, Marine and Environmental Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Meinhard Simon
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
| | - Matthias Wietz
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
- Deep-Sea Ecology and Technology, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
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Zhang YS, Zhang YQ, Zhao XM, Liu XL, Qin QL, Liu NH, Xu F, Chen XL, Zhang YZ, Li PY. Metagenomic insights into the dynamic degradation of brown algal polysaccharides by kelp-associated microbiota. Appl Environ Microbiol 2024; 90:e0202523. [PMID: 38259074 PMCID: PMC10880675 DOI: 10.1128/aem.02025-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Accepted: 12/19/2023] [Indexed: 01/24/2024] Open
Abstract
Marine bacteria play important roles in the degradation and cycling of algal polysaccharides. However, the dynamics of epiphytic bacterial communities and their roles in algal polysaccharide degradation during kelp decay are still unclear. Here, we performed metagenomic analyses to investigate the identities and predicted metabolic abilities of epiphytic bacterial communities during the early and late decay stages of the kelp Saccharina japonica. During kelp decay, the dominant epiphytic bacterial communities shifted from Gammaproteobacteria to Verrucomicrobia and Bacteroidetes. In the early decay stage of S. japonica, epiphytic bacteria primarily targeted kelp-derived labile alginate for degradation, among which the gammaproteobacterial Vibrionaceae (particularly Vibrio) and Psychromonadaceae (particularly Psychromonas), abundant in alginate lyases belonging to the polysaccharide lyase (PL) families PL6, PL7, and PL17, were key alginate degraders. More complex fucoidan was preferred to be degraded in the late decay stage of S. japonica by epiphytic bacteria, predominantly from Verrucomicrobia (particularly Lentimonas), Pirellulaceae of Planctomycetes (particularly Rhodopirellula), Pontiellaceae of Kiritimatiellota, and Flavobacteriaceae of Bacteroidetes, which depended on using glycoside hydrolases (GHs) from the GH29, GH95, and GH141 families and sulfatases from the S1_15, S1_16, S1_17, and S1_25 families to depolymerize fucoidan. The pathways for algal polysaccharide degradation in dominant epiphytic bacterial groups were reconstructed based on analyses of metagenome-assembled genomes. This study sheds light on the roles of different epiphytic bacteria in the degradation of brown algal polysaccharides.IMPORTANCEKelps are important primary producers in coastal marine ecosystems. Polysaccharides, as major components of brown algal biomass, constitute a large fraction of organic carbon in the ocean. However, knowledge of the identities and pathways of epiphytic bacteria involved in the degradation process of brown algal polysaccharides during kelp decay is still elusive. Here, based on metagenomic analyses, the succession of epiphytic bacterial communities and their metabolic potential were investigated during the early and late decay stages of Saccharina japonica. Our study revealed a transition in algal polysaccharide-degrading bacteria during kelp decay, shifting from alginate-degrading Gammaproteobacteria to fucoidan-degrading Verrucomicrobia, Planctomycetes, Kiritimatiellota, and Bacteroidetes. A model for the dynamic degradation of algal cell wall polysaccharides, a complex organic carbon, by epiphytic microbiota during kelp decay was proposed. This study deepens our understanding of the role of epiphytic bacteria in marine algal carbon cycling as well as pathogen control in algal culture.
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Affiliation(s)
- Yi-Shuo Zhang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Yu-Qi Zhang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Xiang-Ming Zhao
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Xiao-Lei Liu
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Qi-Long Qin
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Ning-Hua Liu
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Fei Xu
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Yu-Zhong Zhang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Joint Research Center for Marine Microbiol Science and Technology, Shandong University and Ocean University of China, Qingdao, China
| | - Ping-Yi Li
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
- Joint Research Center for Marine Microbiol Science and Technology, Shandong University and Ocean University of China, Qingdao, China
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Salazar-Alekseyeva K, Herndl GJ, Baltar F. Influence of Salinity on the Extracellular Enzymatic Activities of Marine Pelagic Fungi. J Fungi (Basel) 2024; 10:152. [PMID: 38392824 PMCID: PMC10890631 DOI: 10.3390/jof10020152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/13/2023] [Accepted: 12/15/2023] [Indexed: 02/24/2024] Open
Abstract
Even though fungi are ubiquitous in the biosphere, the ecological knowledge of marine fungi remains rather rudimentary. Also, little is known about their tolerance to salinity and how it influences their activities. Extracellular enzymatic activities (EEAs) are widely used to determine heterotrophic microbes' enzymatic capabilities and substrate preferences. Five marine fungal species belonging to the most abundant pelagic phyla (Ascomycota and Basidiomycota) were grown under non-saline and saline conditions (0 g/L and 35 g/L, respectively). Due to their sensitivity and specificity, fluorogenic substrate analogues were used to determine hydrolytic activity on carbohydrates (β-glucosidase, β-xylosidase, and N-acetyl-β-D-glucosaminidase); peptides (leucine aminopeptidase and trypsin); lipids (lipase); organic phosphorus (alkaline phosphatase), and sulfur compounds (sulfatase). Afterwards, kinetic parameters such as maximum velocity (Vmax) and half-saturation constant (Km) were calculated. All fungal species investigated cleaved these substrates, but some species were more efficient than others. Moreover, most enzymatic activities were reduced in the saline medium, with some exceptions like sulfatase. In non-saline conditions, the average Vmax ranged between 208.5 to 0.02 μmol/g biomass/h, and in saline conditions, 88.4 to 0.02 μmol/g biomass/h. The average Km ranged between 1553.2 and 0.02 μM with no clear influence of salinity. Taken together, our results highlight a potential tolerance of marine fungi to freshwater conditions and indicate that changes in salinity (due to freshwater input or evaporation) might impact their enzymatic activities spectrum and, therefore, their contribution to the oceanic elemental cycles.
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Affiliation(s)
- Katherine Salazar-Alekseyeva
- Bio-Oceanography and Marine Biology Unit, Department of Functional and Evolutionary Ecology, University of Vienna, 1030 Vienna, Austria
- Bioprocess Engineering Group, Department of Agrotechnology and Food Sciences, Wageningen University and Research, 6708 WG Wageningen, The Netherlands
| | - Gerhard J Herndl
- Bio-Oceanography and Marine Biology Unit, Department of Functional and Evolutionary Ecology, University of Vienna, 1030 Vienna, Austria
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research (NIOZ), University of Utrecht, 1790 AB Texel, The Netherlands
| | - Federico Baltar
- Bio-Oceanography and Marine Biology Unit, Department of Functional and Evolutionary Ecology, University of Vienna, 1030 Vienna, Austria
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11
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Wei L, Malinverno A, Colwell F, Goldberg DS. Reactive transport modeling of organic carbon degradation in marine methane hydrate systems. Sci Rep 2024; 14:2837. [PMID: 38310160 PMCID: PMC10838294 DOI: 10.1038/s41598-024-52957-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 01/25/2024] [Indexed: 02/05/2024] Open
Abstract
Natural methane hydrate has often been observed in sand layers that contain no particulate organic carbon (POC), but are surrounded by organic-rich, fine-grained marine muds. In this paper, we develop a reactive transport model (RTM) of a microbially-mediated set of POC degradation reactions, including hydrolysis of POC driven by extracellular enzymes, fermentation of the resulting high-molecular weight dissolved organic carbon (HMW-DOC), and methanogenesis that consumes low-molecular weight dissolved organic carbon (LMW-DOC). These processes are mediated by two groups of microbes, fermenters and methanogens that are heterogeneously distributed in different lithologies, with the largest numbers of microbes in the large pores of coarse-grained layers. We find that the RTM can reproduce methane hydrate occurrences observed in two different geological environments, at Walker Ridge Site 313-H (Gulf of Mexico) and IODP Site U1325 (Cascadia Margin). We also find that microbes can degrade POC even if they are physically separated, as extracellular enzymes and DOC can diffuse away from where they are produced by microbes. Microbial activity is highest at relatively early times after burial at shallow depths and near lithological boundaries, where concentration gradients transport solutes to intervals that contain the most microbes.
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Affiliation(s)
- Li Wei
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, 10964, USA.
| | - Alberto Malinverno
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, 10964, USA
| | - Frederick Colwell
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, 97331, USA
| | - David S Goldberg
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, 10964, USA
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12
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Soru S, Berlino M, Sarà G, Mangano MC, De Vittor C, Pusceddu A. Effects of acidification on the biogeochemistry of unvegetated and seagrass marine sediments. MARINE POLLUTION BULLETIN 2024; 199:115983. [PMID: 38277962 DOI: 10.1016/j.marpolbul.2023.115983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 12/22/2023] [Accepted: 12/23/2023] [Indexed: 01/28/2024]
Abstract
Many studies addressed ocean acidification (OA) effects on marine life, whereas its effects on sedimentary organic matter (OM) have received less attention. We investigated differences in OM features in sediments from unvegetated and seagrass (Posidonia oceanica) beds in a shallow hydrothermal area (Aeolian Archipelago, Mediterranean Sea), under natural (8.1-8.0) and acidified (7.8-7.9) conditions. We show that a pH difference of -0.3 units have minor effects on OM features in unvegetated sediments, but relevant consequences within acidified seagrass meadows, where OM quantity and nutritional quality are lower than those under natural pH conditions. Effects of acidified conditions on OM biogeochemistry vary between unvegetated and seagrass sediments, with lower C degradation rates and longer C turnover time in the former than in the latter. We conclude that OA, although with effects not consistent between unvegetated and vegetated sediments, can affect OM quantity, composition, and degradation, thus having possible far-reaching consequences for benthic trophic webs.
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Affiliation(s)
- Santina Soru
- Department of Life and Environmental Sciences, University of Cagliari, Via Fiorelli 1, 09126 Cagliari, Italy.
| | - Manuel Berlino
- Stazione Zoologica Anton Dohrn, Department of Integrative Marine Ecology (EMI), Sicily Marine Centre, Lungomare Cristoforo Colombo (complesso Roosevelt), 90149 Palermo, Italy; NBFC, National Biodiversity Future Center, Palermo Piazza Marina 61, 90133 Palermo, Italy.
| | - Gianluca Sarà
- NBFC, National Biodiversity Future Center, Palermo Piazza Marina 61, 90133 Palermo, Italy; Department of Earth and Marine Sciences, University of Palermo, Viale delle Scienze Ed. 16, 90128 Palermo, Italy.
| | - Maria Cristina Mangano
- Stazione Zoologica Anton Dohrn, Department of Integrative Marine Ecology (EMI), Sicily Marine Centre, Lungomare Cristoforo Colombo (complesso Roosevelt), 90149 Palermo, Italy; NBFC, National Biodiversity Future Center, Palermo Piazza Marina 61, 90133 Palermo, Italy.
| | - Cinzia De Vittor
- NBFC, National Biodiversity Future Center, Palermo Piazza Marina 61, 90133 Palermo, Italy; National Institute of Oceanography and Applied Geophysics - OGS, 34010 Trieste, Italy.
| | - Antonio Pusceddu
- Department of Life and Environmental Sciences, University of Cagliari, Via Fiorelli 1, 09126 Cagliari, Italy.
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13
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Rothman DH. Slow closure of Earth's carbon cycle. Proc Natl Acad Sci U S A 2024; 121:e2310998121. [PMID: 38241442 PMCID: PMC10823250 DOI: 10.1073/pnas.2310998121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 12/07/2023] [Indexed: 01/21/2024] Open
Abstract
Carbon near the Earth's surface cycles between the production and consumption of organic carbon; the former sequesters carbon dioxide while the latter releases it. Microbes attempt to close the loop, but the longer organic matter survives, the slower microbial degradation becomes. This aging effect leaves observable quantitative signatures: Organic matter decays at rates that are inversely proportional to its age, while microbial populations and concentrations of organic carbon in ocean sediments decrease at distinct powers of age. Yet mechanisms that predict this collective organization remain unknown. Here, I show that these and other observations follow from the assumption that the decay of organic matter is limited by progressively rare extreme fluctuations in the energy available to microbes for decomposition. The theory successfully predicts not only observed scaling exponents but also a previously unobserved scaling regime that emerges when microbes subsist on the minimum energy flux required for survival. The resulting picture suggests that the carbon cycle's age-dependent dynamics are analogous to the slow approach to equilibrium in disordered systems. The impact of these slow dynamics is profound: They preclude complete oxidation of organic carbon in sediments, thereby freeing molecular oxygen to accumulate in the atmosphere.
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Affiliation(s)
- Daniel H. Rothman
- Lorenz Center, Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA02139
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14
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McNichol SM, Sanchez-Quete F, Loeb SK, Teske AP, Shah Walter SR, Mahmoudi N. Dynamics of carbon substrate competition among heterotrophic microorganisms. THE ISME JOURNAL 2024; 18:wrae018. [PMID: 38366177 PMCID: PMC10942773 DOI: 10.1093/ismejo/wrae018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 01/06/2024] [Accepted: 01/26/2024] [Indexed: 02/18/2024]
Abstract
Growing evidence suggests that interactions among heterotrophic microorganisms influence the efficiency and rate of organic matter turnover. These interactions are dynamic and shaped by the composition and availability of resources in their surrounding environment. Heterotrophic microorganisms inhabiting marine environments often encounter fluctuations in the quality and quantity of carbon inputs, ranging from simple sugars to large, complex compounds. Here, we experimentally tested how the chemical complexity of carbon substrates affects competition and growth dynamics between two heterotrophic marine isolates. We tracked cell density using species-specific polymerase chain reaction (PCR) assays and measured rates of microbial CO2 production along with associated isotopic signatures (13C and 14C) to quantify the impact of these interactions on organic matter remineralization. The observed cell densities revealed substrate-driven interactions: one species exhibited a competitive advantage and quickly outgrew the other when incubated with a labile compound whereas both species seemed to coexist harmoniously in the presence of more complex organic matter. Rates of CO2 respiration revealed that coincubation of these isolates enhanced organic matter turnover, sometimes by nearly 2-fold, compared to their incubation as mono-cultures. Isotopic signatures of respired CO2 indicated that coincubation resulted in a greater remineralization of macromolecular organic matter. These results demonstrate that simple substrates promote competition whereas high substrate complexity reduces competitiveness and promotes the partitioning of degradative activities into distinct niches, facilitating coordinated utilization of the carbon pool. Taken together, this study yields new insight into how the quality of organic matter plays a pivotal role in determining microbial interactions within marine environments.
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Affiliation(s)
- Samuel M McNichol
- Department of Earth and Planetary Sciences, McGill University, 3450 University St, Montréal, Quebec H3A 0E8, Canada
| | - Fernando Sanchez-Quete
- Department of Civil Engineering, McGill University, 817 Rue Sherbrooke Ouest, Montréal, Quebec H3A 0C3, Canada
| | - Stephanie K Loeb
- Department of Civil Engineering, McGill University, 817 Rue Sherbrooke Ouest, Montréal, Quebec H3A 0C3, Canada
| | - Andreas P Teske
- Department of Earth, Marine and Environmental Sciences, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Sunita R Shah Walter
- School of Marine Science and Policy, University of Delaware, 700 Pilottown Rd, Lewes, DE 19958, United States
| | - Nagissa Mahmoudi
- Department of Earth and Planetary Sciences, McGill University, 3450 University St, Montréal, Quebec H3A 0E8, Canada
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15
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Zhang L, Wang X, Wang H, Cao Y, Weng L, Ma L. Electric field as extracellular enzyme activator promotes conversion of lignocellulose to humic acid in composting process. BIORESOURCE TECHNOLOGY 2024; 391:129948. [PMID: 37914057 DOI: 10.1016/j.biortech.2023.129948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/22/2023] [Accepted: 10/28/2023] [Indexed: 11/03/2023]
Abstract
To promote efficient conversion of lignocellulose to humus (HS) during composting, a novel bio-electrochemical technology was applied and explored the effect and mechanism of electrification on carbon conversion during different composting periods. The results showed that supplementary electric field played different roles during composting. In the early stage, organic matter mineralization was significantly accelerated under electric field application, that was embodied in a 29.8% increase of CO2 emission due to the enhanced metabolic activity of microorganisms. However, the electric field functioned as an extracellular enzyme activator during the later stage since the abundance of functional microorganisms related to lignocellulose degradation was increased by 1.5-2.8 fold that effectively promoted the conversion of lignocellulose to HS. The humic acid content of the compost products increased by 23.0-32.9% compared with control. This study elucidated how electric fields affect carbon conversion during composting, which provides a novel strategy for returning agricultural wastes to soil.
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Affiliation(s)
- Lu Zhang
- Key Laboratory of Agricultural Water Resources, Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetic and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, China; University of Chinese Academy of Sciences, Beijing, China
| | - Xuan Wang
- Key Laboratory of Agricultural Water Resources, Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetic and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, China; Xiongan Institute of Innovation, Chinese Academy of Sciences, Xiongan, China
| | - Hongge Wang
- Key Laboratory of Agricultural Water Resources, Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetic and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yubo Cao
- Key Laboratory of Agricultural Water Resources, Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetic and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, China; University of Chinese Academy of Sciences, Beijing, China
| | - Liping Weng
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China; Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Lin Ma
- Key Laboratory of Agricultural Water Resources, Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetic and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, China.
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16
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Perkins AK, Rose AL, Grossart HP, Schulz KG, Neubauer D, Tonge MP, Rosentreter JA, Eyre BD, Rojas-Jimenez K, Deschaseaux E, Oakes JM. Fungi increases kelp (Ecklonia radiata) remineralisation and dissolved organic carbon, alkalinity, and dimethylsulfoniopropionate (DMSP) production. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:166957. [PMID: 37704140 DOI: 10.1016/j.scitotenv.2023.166957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 09/06/2023] [Accepted: 09/08/2023] [Indexed: 09/15/2023]
Abstract
Fungi are key players in terrestrial organic matter (OM) degradation, but little is known about their role in marine environments. Here we compared the degradation of kelp (Ecklonia radiata) in mesocosms with and without fungicides over 45 days. The aim was to improve our understanding of the vital role of fungal OM degradation and remineralisation and its relevance to marine biogeochemical cycles (e.g., carbon, nitrogen, sulfur, or volatile sulfur). In the presence of fungi, 68 % of the kelp detritus degraded over 45 days, resulting in the production of 0.6 mol of dissolved organic carbon (DOC), 0.16 mol of dissolved inorganic carbon (DIC), 0.23 mol of total alkalinity (TA), and 0.076 mol of CO2, which was subsequently emitted to the atmosphere. Conversely, when fungi were inhibited, the bacterial community diversity was reduced, and only 25 % of the kelp detritus degraded over 45 days. The application of fungicides resulted in the generation of an excess amount of 1.5 mol of DOC, but we observed only 0.02 mol of DIC, and 0.04 mol of TA per one mole of kelp detritus, accompanied by a CO2 emission of 0.081 mol. In contrast, without fungi, remineralisation of kelp detritus to DIC, TA, dimethyl sulfide (DMS), dimethylsulfoniopropionate (DMSP) and methanethiol (MeSH) was significantly reduced. Fungal kelp remineralisation led to a remarkable 100,000 % increase in DMSP production. The observed substantial changes in sediment chemistry when fungi are inhibited highlight the important biogeochemical role of fungal remineralisation, which likely plays a crucial role in defining coastal biogeochemical cycling, blue carbon sequestration, and thus climate regulation.
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Affiliation(s)
- Anita K Perkins
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia; Southern Cross Geoscience, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia.
| | - Andrew L Rose
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia; Southern Cross Geoscience, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
| | - Hans-Peter Grossart
- Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB), Experimental Limnology, 16775 Neuglobsow, Germany; University of Potsdam, Institute of Biochemistry and Biology, Maulbeerallee 2, 14469 Potsdam, Germany
| | - Kai G Schulz
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
| | - Darshan Neubauer
- Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB), Experimental Limnology, 16775 Neuglobsow, Germany; University of Potsdam, Institute of Biochemistry and Biology, Maulbeerallee 2, 14469 Potsdam, Germany
| | - Matthew P Tonge
- Southern Cross Geoscience, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
| | - Judith A Rosentreter
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
| | - Bradley D Eyre
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
| | | | - Elisabeth Deschaseaux
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
| | - Joanne M Oakes
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
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17
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Salazar-Alekseyeva K, Herndl GJ, Baltar F. Release of cell-free enzymes by marine pelagic fungal strains. FRONTIERS IN FUNGAL BIOLOGY 2023; 4:1209265. [PMID: 38025900 PMCID: PMC10658710 DOI: 10.3389/ffunb.2023.1209265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 09/22/2023] [Indexed: 12/01/2023]
Abstract
Fungi are ubiquitous organisms that secrete different enzymes to cleave large molecules into smaller ones so that can then be assimilated. Recent studies suggest that fungi are also present in the oceanic water column harboring the enzymatic repertoire necessary to cleave carbohydrates and proteins. In marine prokaryotes, the cell-free fraction is an important contributor to the oceanic extracellular enzymatic activities (EEAs), but the release of cell-free enzymes by marine fungi remains unknown. Here, to study the cell-free enzymatic activities of marine fungi and the potential influence of salinity on them, five strains of marine fungi that belong to the most abundant pelagic phyla (Ascomycota and Basidiomycota), were grown under non-saline and saline conditions (0 g/L and 35 g/L, respectively). The biomass was separated from the medium by filtration (0.2 μm), and the filtrate was used to perform fluorogenic enzymatic assays with substrate analogues of carbohydrates, lipids, organic phosphorus, sulfur moieties, and proteins. Kinetic parameters such as maximum velocity (Vmax) and half-saturation constant (Km) were obtained. The species studied were able to release cell-free enzymes, and this represented up to 85.1% of the respective total EEA. However, this differed between species and enzymes, with some of the highest contributions being found in those with low total EEA, with some exceptions. This suggests that some of these contributions to the enzymatic pool might be minimal compared to those with higher total EEA. Generally, in the saline medium, the release of cell-free enzymes degrading carbohydrates was reduced compared to the non-saline medium, but those degrading lipids and sulfur moieties were increased. For the remaining substrates, there was not a clear influence of the salinity. Taken together, our results suggest that marine fungi are potential contributors to the oceanic dissolved (i.e., cell-free) enzymatic pool. Our results also suggest that, under salinity changes, a potential effect of global warming, the hydrolysis of organic matter by marine fungal cell-free enzymes might be affected and hence, their potential contribution to the oceanic biogeochemical cycles.
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Affiliation(s)
- Katherine Salazar-Alekseyeva
- Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Vienna, Austria
- Department of Agrotechnology and Food Sciences, Bioprocess Engineering Group, Wageningen University and Research, Wageningen, Netherlands
| | - Gerhard J. Herndl
- Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Vienna, Austria
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research (NIOZ), University of Utrecht, Texel, Netherlands
| | - Federico Baltar
- Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Vienna, Austria
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18
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Dutschei T, Beidler I, Bartosik D, Seeßelberg JM, Teune M, Bäumgen M, Ferreira SQ, Heldmann J, Nagel F, Krull J, Berndt L, Methling K, Hein M, Becher D, Langer P, Delcea M, Lalk M, Lammers M, Höhne M, Hehemann JH, Schweder T, Bornscheuer UT. Marine Bacteroidetes enzymatically digest xylans from terrestrial plants. Environ Microbiol 2023; 25:1713-1727. [PMID: 37121608 DOI: 10.1111/1462-2920.16390] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 04/18/2023] [Indexed: 05/02/2023]
Abstract
Marine Bacteroidetes that degrade polysaccharides contribute to carbon cycling in the ocean. Organic matter, including glycans from terrestrial plants, might enter the oceans through rivers. Whether marine bacteria degrade structurally related glycans from diverse sources including terrestrial plants and marine algae was previously unknown. We show that the marine bacterium Flavimarina sp. Hel_I_48 encodes two polysaccharide utilization loci (PULs) which degrade xylans from terrestrial plants and marine algae. Biochemical experiments revealed activity and specificity of the encoded xylanases and associated enzymes of these PULs. Proteomics indicated that these genomic regions respond to glucuronoxylans and arabinoxylans. Substrate specificities of key enzymes suggest dedicated metabolic pathways for xylan utilization. Some of the xylanases were active on different xylans with the conserved β-1,4-linked xylose main chain. Enzyme activity was consistent with growth curves showing Flavimarina sp. Hel_I_48 uses structurally different xylans. The observed abundance of related xylan-degrading enzyme repertoires in genomes of other marine Bacteroidetes indicates similar activities are common in the ocean. The here presented data show that certain marine bacteria are genetically and biochemically variable enough to access parts of structurally diverse xylans from terrestrial plants as well as from marine algal sources.
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Affiliation(s)
- Theresa Dutschei
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University Greifswald, Greifswald, Germany
| | - Irena Beidler
- Department of Pharmaceutical Biotechnology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Daniel Bartosik
- Department of Pharmaceutical Biotechnology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
- Institute of Marine Biotechnology e.V., Greifswald, Germany
| | - Julia-Maria Seeßelberg
- Department of Protein Biochemistry, Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Michelle Teune
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University Greifswald, Greifswald, Germany
| | - Marcus Bäumgen
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University Greifswald, Greifswald, Germany
| | - Soraia Querido Ferreira
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University Greifswald, Greifswald, Germany
| | - Julia Heldmann
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University Greifswald, Greifswald, Germany
| | - Felix Nagel
- Department of Biophysical Chemistry, Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Joris Krull
- Institute of Marine Biotechnology e.V., Greifswald, Germany
- Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Leona Berndt
- Department of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Karen Methling
- Department of Cellular Biochemistry and Metabolomics, Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Martin Hein
- Department of Organic Chemistry, Institute of Chemistry, University of Rostock, Rostock, Germany
| | - Dörte Becher
- Department of Microbial Proteomics, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Peter Langer
- Department of Organic Chemistry, Institute of Chemistry, University of Rostock, Rostock, Germany
| | - Mihaela Delcea
- Department of Biophysical Chemistry, Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Michael Lalk
- Department of Cellular Biochemistry and Metabolomics, Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Michael Lammers
- Department of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Matthias Höhne
- Department of Protein Biochemistry, Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Jan-Hendrik Hehemann
- Institute of Marine Biotechnology e.V., Greifswald, Germany
- Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Thomas Schweder
- Department of Pharmaceutical Biotechnology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
- Institute of Marine Biotechnology e.V., Greifswald, Germany
| | - Uwe T Bornscheuer
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University Greifswald, Greifswald, Germany
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19
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Moore OW, Curti L, Woulds C, Bradley JA, Babakhani P, Mills BJW, Homoky WB, Xiao KQ, Bray AW, Fisher BJ, Kazemian M, Kaulich B, Dale AW, Peacock CL. Long-term organic carbon preservation enhanced by iron and manganese. Nature 2023; 621:312-317. [PMID: 37532941 PMCID: PMC10499600 DOI: 10.1038/s41586-023-06325-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 06/14/2023] [Indexed: 08/04/2023]
Abstract
The balance between degradation and preservation of sedimentary organic carbon (OC) is important for global carbon and oxygen cycles1. The relative importance of different mechanisms and environmental conditions contributing to marine sedimentary OC preservation, however, remains unclear2-8. Simple organic molecules can be geopolymerized into recalcitrant forms by means of the Maillard reaction5, although reaction kinetics at marine sedimentary temperatures are thought to be slow9,10. More recent work in terrestrial systems suggests that the reaction can be catalysed by manganese minerals11-13, but the potential for the promotion of geopolymerized OC formation at marine sedimentary temperatures is uncertain. Here we present incubation experiments and find that iron and manganese ions and minerals abiotically catalyse the Maillard reaction by up to two orders of magnitude at temperatures relevant to continental margins where most preservation occurs4. Furthermore, the chemical signature of the reaction products closely resembles dissolved and total OC found in continental margin sediments globally. With the aid of a pore-water model14, we estimate that iron- and manganese-catalysed transformation of simple organic molecules into complex macromolecules might generate on the order of approximately 4.1 Tg C yr-1 for preservation in marine sediments. In the context of perhaps only about 63 Tg C yr-1 variation in sedimentary organic preservation over the past 300 million years6, we propose that variable iron and manganese inputs to the ocean could exert a substantial but hitherto unexplored impact on global OC preservation over geological time.
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Affiliation(s)
- Oliver W Moore
- School of Earth and Environment, University of Leeds, Leeds, UK.
| | - Lisa Curti
- School of Earth and Environment, University of Leeds, Leeds, UK
| | - Clare Woulds
- School of Geography, University of Leeds, Leeds, UK
| | - James A Bradley
- School of Geography, Queen Mary University of London, London, UK
- Department of Geochemistry, GFZ, German Research Centre for Geosciences, Potsdam, Germany
| | | | | | | | - Ke-Qing Xiao
- School of Earth and Environment, University of Leeds, Leeds, UK
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Andrew W Bray
- School of Earth and Environment, University of Leeds, Leeds, UK
| | - Ben J Fisher
- School of Earth and Environment, University of Leeds, Leeds, UK
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
| | - Majid Kazemian
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, UK
| | - Burkhard Kaulich
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, UK
| | - Andrew W Dale
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
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20
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Tsikopoulou I, Chatzivasileiou D, Dimitriou PD, Magiopoulos I, Papageorgiou N, Karakassis I. Contribution of holothuroids to the bioremediation and stimulation of the benthic microbial metabolism in aquaculture. MARINE POLLUTION BULLETIN 2023; 194:115418. [PMID: 37611338 DOI: 10.1016/j.marpolbul.2023.115418] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 08/10/2023] [Accepted: 08/13/2023] [Indexed: 08/25/2023]
Abstract
The implementation of sustainable system designs in aquaculture comprises the biological treatment of pollutants. In order to test the potential of Holothuria (Roweothuria) poli as a candidate for bioremediation of aquaculture wastes, the effect of this species on the benthic microbial activity was studied. Two experimental treatments, with and without holothuroids, were allocated in two benthocosms, each one containing four replicate tanks with undisturbed sediment and a volume of water above it. It was anticipated that H. poli could affect the overall assimilative capacity of the aquaculture effluent system either through the consumption of particulate organic matter or through the stimulation of benthic microbial metabolism. Indeed, the results indicated that the microbial activity related to the mineralization of the N and C was significantly different between the treatments verifying our hypothesis that deposit-feeders that move above or inside the sediment matrix can accelerate the depletion of organic matter through bioturbation.
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Affiliation(s)
- Irini Tsikopoulou
- Hellenic Centre for Marine Research, Institute of Marine Biological Resources and Inland Waters, GR 71003 Heraklion, Greece; Department of Biology, University of Crete, GR 70013 Heraklion, Greece.
| | | | | | - Iordanis Magiopoulos
- Hellenic Centre for Marine Research, Institute of Oceanography, GR 71003 Heraklion, Greece
| | - Nafsika Papageorgiou
- Department of Agricultural Development, Agrofood & Management of Natural Resources, National and Kapodistrian University of Athens, GR 34400 Athens, Greece
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21
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Tinta T, Zhao Z, Bayer B, Herndl GJ. Jellyfish detritus supports niche partitioning and metabolic interactions among pelagic marine bacteria. MICROBIOME 2023; 11:156. [PMID: 37480075 PMCID: PMC10360251 DOI: 10.1186/s40168-023-01598-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 06/13/2023] [Indexed: 07/23/2023]
Abstract
BACKGROUND Jellyfish blooms represent a significant but largely overlooked source of labile organic matter (jelly-OM) in the ocean, characterized by a high protein content. Decaying jellyfish are important carriers for carbon export to the ocean's interior. To accurately incorporate them into biogeochemical models, the interactions between microbes and jelly-OM have yet to be fully characterized. We conducted jelly-OM enrichment experiments in microcosms to simulate the scenario experienced by the coastal pelagic microbiome after the decay of a jellyfish bloom. We combined metagenomics, endo- and exo-metaproteomic approaches to obtain a mechanistic understanding on the metabolic network operated by the jelly-OM degrading bacterial consortium. RESULTS Our analysis revealed that OM released during the decay of jellyfish blooms triggers a rapid shuffling of the taxonomic and functional profile of the pelagic bacterial community, resulting in a significant enrichment of protein/amino acid catabolism-related enzymes in the jelly-OM degrading community dominated by Pseudoalteromonadaceae, Alteromonadaceae and Vibrionaceae, compared to unamended control treatments. In accordance with the proteinaceous character of jelly-OM, Pseudoalteromonadaceae synthesized and excreted enzymes associated with proteolysis, while Alteromonadaceae contributed to extracellular hydrolysis of complex carbohydrates and organophosphorus compounds. In contrast, Vibrionaceae synthesized transporter proteins for peptides, amino acids and carbohydrates, exhibiting a cheater-type lifestyle, i.e. benefiting from public goods released by others. In the late stage of jelly-OM degradation, Rhodobacteraceae and Alteromonadaceae became dominant, growing on jelly-OM left-overs or bacterial debris, potentially contributing to the accumulation of dissolved organic nitrogen compounds and inorganic nutrients, following the decay of jellyfish blooms. CONCLUSIONS Our findings indicate that specific chemical and metabolic fingerprints associated with decaying jellyfish blooms are substantially different to those previously associated with decaying phytoplankton blooms, potentially altering the functioning and biogeochemistry of marine systems. We show that decaying jellyfish blooms are associated with the enrichment in extracellular collagenolytic bacterial proteases, which could act as virulence factors in human and marine organisms' disease, with possible implications for marine ecosystem services. Our study also provides novel insights into niche partitioning and metabolic interactions among key jelly-OM degraders operating a complex metabolic network in a temporal cascade of biochemical reactions to degrade pulses of jellyfish-bloom-specific compounds in the water column. Video Abstract.
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Affiliation(s)
- Tinkara Tinta
- Marine Biology Station Piran, National Institute of Biology, Piran, Slovenia.
- Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Vienna, Austria.
| | - Zihao Zhao
- Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Vienna, Austria
| | - Barbara Bayer
- Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Gerhard J Herndl
- Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Vienna, Austria
- NIOZ, Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, Utrecht University, Den Burg, The Netherlands
- Vienna Metabolomics & Proteomics Center, University of Vienna, Vienna, Austria
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22
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Liu Y, Ma C, Sun J. Integrated FT-ICR MS and metabolome reveals diatom-derived organic matter by bacterial transformation under warming and acidification. iScience 2023; 26:106812. [PMID: 37213222 PMCID: PMC10197009 DOI: 10.1016/j.isci.2023.106812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 02/21/2023] [Accepted: 05/01/2023] [Indexed: 05/23/2023] Open
Abstract
Bacterial transformation and processing of diatom-derived organic matter (OM) is extremely important for the cycling of production and energy in marine ecosystems; this process contributes to the production of microbial food webs. In this study, a cultivable bacterium (Roseobacter sp. SD-R1) from the marine diatom Skeletonema dohrnii were isolated and identified. A combined Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS)/untargeted metabolomics approach was used to synthesize the results of bacterial transformation with dissolved OM (DOM) and lysate OM (LOM) under warming and acidification through laboratory experiments. Roseobacter sp. SD-R1 had different preferences for the conversion of molecules in S. dohrnii-derived DOM and LOM treatments. The effects of warming and acidification contribute to the increased number and complexity of molecules of carbon, hydrogen, oxygen, nitrogen, and sulfur after the bacterial transformation of OM. The chemical complexity generated by bacterial metabolism provides new insights into the mechanisms that shape OM complexity.
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Affiliation(s)
- Yang Liu
- Institute for Advance Marine Research, China University of Geosciences, Guangzhou 511462, China
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China
- Institute of Marine Science and Technology, Shandong University, Qingdao 266237, China
| | - Chao Ma
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Jun Sun
- Institute for Advance Marine Research, China University of Geosciences, Guangzhou 511462, China
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China
- Corresponding author
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23
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Sakkos JK, Santos-Merino M, Kokarakis EJ, Li B, Fuentes-Cabrera M, Zuliani P, Ducat DC. Predicting partner fitness based on spatial structuring in a light-driven microbial community. PLoS Comput Biol 2023; 19:e1011045. [PMID: 37134119 PMCID: PMC10184905 DOI: 10.1371/journal.pcbi.1011045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 05/15/2023] [Accepted: 03/22/2023] [Indexed: 05/04/2023] Open
Abstract
Microbial communities have vital roles in systems essential to human health and agriculture, such as gut and soil microbiomes, and there is growing interest in engineering designer consortia for applications in biotechnology (e.g., personalized probiotics, bioproduction of high-value products, biosensing). The capacity to monitor and model metabolite exchange in dynamic microbial consortia can provide foundational information important to understand the community level behaviors that emerge, a requirement for building novel consortia. Where experimental approaches for monitoring metabolic exchange are technologically challenging, computational tools can enable greater access to the fate of both chemicals and microbes within a consortium. In this study, we developed an in-silico model of a synthetic microbial consortia of sucrose-secreting Synechococcus elongatus PCC 7942 and Escherichia coli W. Our model was built on the NUFEB framework for Individual-based Modeling (IbM) and optimized for biological accuracy using experimental data. We showed that the relative level of sucrose secretion regulates not only the steady-state support for heterotrophic biomass, but also the temporal dynamics of consortia growth. In order to determine the importance of spatial organization within the consortium, we fit a regression model to spatial data and used it to accurately predict colony fitness. We found that some of the critical parameters for fitness prediction were inter-colony distance, initial biomass, induction level, and distance from the center of the simulation volume. We anticipate that the synergy between experimental and computational approaches will improve our ability to design consortia with novel function.
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Affiliation(s)
- Jonathan K Sakkos
- Plant Research Laboratory, Michigan State University, East Lansing, Michigan, United States of America
| | - María Santos-Merino
- Plant Research Laboratory, Michigan State University, East Lansing, Michigan, United States of America
| | - Emmanuel J Kokarakis
- Plant Research Laboratory, Michigan State University, East Lansing, Michigan, United States of America
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Bowen Li
- School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Miguel Fuentes-Cabrera
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Paolo Zuliani
- Dipartimento di Informatica, Università di Roma "La Sapienza", Rome, Italy
| | - Daniel C Ducat
- Plant Research Laboratory, Michigan State University, East Lansing, Michigan, United States of America
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, United States of America
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24
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Šebela M. The use of matrix-assisted laser desorption/ionization mass spectrometry in enzyme activity assays and its position in the context of other available methods. MASS SPECTROMETRY REVIEWS 2023; 42:1008-1031. [PMID: 34549449 DOI: 10.1002/mas.21733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/28/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Activity assays are indispensable for studying biochemical properties of enzymes. The purposes of measuring activity are wide ranging from a simple detection of the presence of an enzyme to kinetic experiments evaluating the substrate specificity, reaction mechanisms, and susceptibility to inhibitors. Common activity assay methods include spectroscopy, electrochemical sensors, or liquid chromatography coupled with various detection techniques. This review focuses on the use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) as a growing and modern alternative, which offers high speed of analysis, sensitivity, versatility, possibility of automation, and cost-effectiveness. It may reveal reaction intermediates, side products or measure more enzymes at once. The addition of an internal standard or calculating the ratios of the substrate and product peak intensities and areas overcome the inherent inhomogeneous distribution of analyte and matrix in the sample spot, which otherwise results in a poor reproducibility. Examples of the application of MALDI-TOF MS for assaying hydrolases (including peptidases and β-lactamases for antibiotic resistance tests) and other enzymes are provided. Concluding remarks summarize advantages and challenges coming from the present experience, and draw future perspectives such as a screening of large libraries of chemical compounds for their substrate or inhibitory properties towards enzymes.
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Affiliation(s)
- Marek Šebela
- Department of Biochemistry, Faculty of Science, and CATRIN, Palacký University, Olomouc, Czech Republic
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25
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Hu T, Luo M, Qi Y, He D, Chen L, Xu Y, Chen D. Molecular evidence for the production of labile, sulfur-bearing dissolved organic matter in the seep sediments of the South China Sea. WATER RESEARCH 2023; 233:119732. [PMID: 36801578 DOI: 10.1016/j.watres.2023.119732] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 02/05/2023] [Accepted: 02/11/2023] [Indexed: 06/18/2023]
Abstract
Cold seeps with methane-rich fluids leaking out of the seafloor usually support massive biomass of chemosynthetic organisms and associated fauna. A substantial amount of methane is converted to dissolved inorganic carbon by microbial metabolism, and this process also releases dissolved organic matter (DOM) into pore water. Here, pore water samples from "Haima cold seeps" sediments and the non-seep reference sediments in the northern South China Sea were analyzed for optical properties and molecular compositions of pore water DOM. Our results showed that the relative abundance of protein-like DOM, H/Cwa and molecular lability boundary percentage (MLBL%) in the seep sediments were significantly higher than those in the reference sediments, indicating that more labile DOM related to unsaturated aliphatic compounds is produced in the seep sediments. Spearman's correlation of the fluoresce and molecular data suggested that the humic-like components (C1 and C2) mainly constituted the refractory compounds (CRAM, highly unsaturated and aromatics compounds). In contrast, the protein-like component (C3) had high H/C ratios featuring high degree of DOM lability. The amount of S-containing formulas (CHOS and CHONS) was greatly elevated in the seep sediments, likely caused by abiotic and biotic sulfurization of DOM in the sulfidic environment. Although the abiotic sulfurization was proposed to have a stabilizing effect on organic matter, our results implied that the biotic sulfurization in the cold seep sediments would increase DOM lability. Overall, the labile DOM accumulated in the seep sediments is closely linked to methane oxidation, which not only support heterotrophic communities and but also likely have an impact on carbon and sulfur cycling in the sediments and the ocean.
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Affiliation(s)
- Tingcang Hu
- College of Geography and Environment, Liaocheng University, Liaocheng, China
| | - Min Luo
- Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China.
| | - Yulin Qi
- Institute of Surface-Earth System Science, College of Earth System Science, Tianjin University, Tianjin, China
| | - Ding He
- Department of Ocean Science and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Hong Kong, China
| | - Linying Chen
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
| | - Yunping Xu
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
| | - Duofu Chen
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China.
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26
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Kang JY, Song HY, Kim JM. Agarolytic Pathway in the Newly Isolated Aquimarina sp. Bacterial Strain ERC-38 and Characterization of a Putative β-agarase. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2023; 25:314-327. [PMID: 37002465 PMCID: PMC10163077 DOI: 10.1007/s10126-023-10206-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 03/19/2023] [Indexed: 05/06/2023]
Abstract
Marine microbes, particularly Bacteroidetes, are a rich source of enzymes that can degrade diverse marine polysaccharides. Aquimarina sp. ERC-38, which belongs to the Bacteroidetes phylum, was isolated from seawater in South Korea. It showed agar-degrading activity and required an additional carbon source for growth on marine broth 2216. Here, the genome of the strain was sequenced to understand its agar degradation mechanism, and 3615 protein-coding sequences were predicted, which were assigned putative functions according to their annotated functional feature categories. In silico genome analysis revealed that the ERC-38 strain has several carrageenan-degrading enzymes but could not degrade carrageenan because it lacked genes encoding κ-carrageenanase and S1_19A type sulfatase. Moreover, the strain possesses multiple genes predicted to encode enzymes involved in agarose degradation, which are located in a polysaccharide utilization locus. Among the enzymes, Aq1840, which is closest to ZgAgaC within the glycoside hydrolase 16 family, was characterized using a recombinant enzyme expressed in Escherichia coli BL21 (DE3) cells. An enzyme assay revealed that recombinant Aq1840 mainly converts agarose to NA4. Moreover, recombinant Aq1840 could weakly hydrolyze A5 into A3 and NA2. These results showed that Aq1840 is involved in at least the initial agar degradation step prior to the metabolic pathway that uses agarose as a carbon source for growth of the strain. Thus, this enzyme can be applied to development and manufacturing industry for prebiotic and antioxidant food additive. Furthermore, our genome sequence analysis revealed that the strain is a potential resource for research on marine polysaccharide degradation mechanisms and carbon cycling.
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Affiliation(s)
- Ji Young Kang
- Industrial Microbiology and Bioprocess Research Center, Korea Research, Institute of Bioscience and Biotechnology (KRIBB) , Jeongeup, Jeonbuk, 56212, Republic of Korea.
| | - Ha-Yeon Song
- Department of Life and Environmental Sciences, Institute of Life Science and Natural Resources, Wonkwang University, Iksan, Jeonbuk, 54538, Republic of Korea
| | - Jung-Mi Kim
- Department of Life and Environmental Sciences, Institute of Life Science and Natural Resources, Wonkwang University, Iksan, Jeonbuk, 54538, Republic of Korea.
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27
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Lu J, Shu Y, Zhang H, Zhang S, Zhu C, Ding W, Zhang W. The Landscape of Global Ocean Microbiome: From Bacterioplankton to Biofilms. Int J Mol Sci 2023; 24:ijms24076491. [PMID: 37047466 PMCID: PMC10095273 DOI: 10.3390/ijms24076491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 03/26/2023] [Accepted: 03/27/2023] [Indexed: 04/01/2023] Open
Abstract
The development of metagenomics has opened up a new era in the study of marine microbiota, which play important roles in biogeochemical cycles. In recent years, the global ocean sampling expeditions have spurred this research field toward a deeper understanding of the microbial diversities and functions spanning various lifestyles, planktonic (free-living) or sessile (biofilm-associated). In this review, we deliver a comprehensive summary of marine microbiome datasets generated in global ocean expeditions conducted over the last 20 years, including the Sorcerer II GOS Expedition, the Tara Oceans project, the bioGEOTRACES project, the Micro B3 project, the Bio-GO-SHIP project, and the Marine Biofilms. These datasets have revealed unprecedented insights into the microscopic life in our oceans and led to the publication of world-leading research. We also note the progress of metatranscriptomics and metaproteomics, which are confined to local marine microbiota. Furthermore, approaches to transforming the global ocean microbiome datasets are highlighted, and the state-of-the-art techniques that can be combined with data analyses, which can present fresh perspectives on marine molecular ecology and microbiology, are proposed.
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Affiliation(s)
- Jie Lu
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266100, China
| | - Yi Shu
- MOE Key Laboratory of Marine Genetics and Breeding, Ocean University of China, Qingdao 266100, China;
| | - Heng Zhang
- College of Marine Life Sciences, Ocean University of China, Qingdao 266100, China
| | - Shangxian Zhang
- Haide College, Ocean University of China, Qingdao 266100, China
| | - Chengrui Zhu
- Haide College, Ocean University of China, Qingdao 266100, China
| | - Wei Ding
- MOE Key Laboratory of Marine Genetics and Breeding, Ocean University of China, Qingdao 266100, China;
- College of Marine Life Sciences, Ocean University of China, Qingdao 266100, China
- Haide College, Ocean University of China, Qingdao 266100, China
- Correspondence: (W.D.); (W.Z.)
| | - Weipeng Zhang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266100, China
- College of Marine Life Sciences, Ocean University of China, Qingdao 266100, China
- Haide College, Ocean University of China, Qingdao 266100, China
- Correspondence: (W.D.); (W.Z.)
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28
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Cell aggregation is associated with enzyme secretion strategies in marine polysaccharide-degrading bacteria. THE ISME JOURNAL 2023; 17:703-711. [PMID: 36813911 PMCID: PMC10119383 DOI: 10.1038/s41396-023-01385-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 02/06/2023] [Accepted: 02/13/2023] [Indexed: 02/24/2023]
Abstract
Polysaccharide breakdown by bacteria requires the activity of enzymes that degrade polymers either intra- or extra-cellularly. The latter mechanism generates a localized pool of breakdown products that are accessible to the enzyme producers themselves as well as to other organisms. Marine bacterial taxa often show marked differences in the production and secretion of degradative enzymes that break down polysaccharides. These differences can have profound effects on the pool of diffusible breakdown products and hence on the ecological dynamics. However, the consequences of differences in enzymatic secretions on cellular growth dynamics and interactions are unclear. Here we study growth dynamics of single cells within populations of marine Vibrionaceae strains that grow on the abundant marine polymer alginate, using microfluidics coupled to quantitative single-cell analysis and mathematical modelling. We find that strains that have low extracellular secretions of alginate lyases aggregate more strongly than strains that secrete high levels of enzymes. One plausible reason for this observation is that low secretors require a higher cellular density to achieve maximal growth rates in comparison with high secretors. Our findings indicate that increased aggregation increases intercellular synergy amongst cells of low-secreting strains. By mathematically modelling the impact of the level of degradative enzyme secretion on the rate of diffusive oligomer loss, we find that enzymatic secretion capability modulates the propensity of cells within clonal populations to cooperate or compete with each other. Our experiments and models demonstrate that enzymatic secretion capabilities can be linked with the propensity of cell aggregation in marine bacteria that extracellularly catabolize polysaccharides.
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29
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Nelson CE, Wegley Kelly L, Haas AF. Microbial Interactions with Dissolved Organic Matter Are Central to Coral Reef Ecosystem Function and Resilience. ANNUAL REVIEW OF MARINE SCIENCE 2023; 15:431-460. [PMID: 36100218 DOI: 10.1146/annurev-marine-042121-080917] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
To thrive in nutrient-poor waters, coral reefs must retain and recycle materials efficiently. This review centers microbial processes in facilitating the persistence and stability of coral reefs, specifically the role of these processes in transforming and recycling the dissolved organic matter (DOM) that acts as an invisible currency in reef production, nutrient exchange, and organismal interactions. The defining characteristics of coral reefs, including high productivity, balanced metabolism, high biodiversity, nutrient retention, and structural complexity, are inextricably linked to microbial processing of DOM. The composition of microbes and DOM in reefs is summarized, and the spatial and temporal dynamics of biogeochemical processes carried out by microorganisms in diverse reef habitats are explored in a variety of key reef processes, including decomposition, accretion, trophictransfer, and macronutrient recycling. Finally, we examine how widespread habitat degradation of reefs is altering these important microbe-DOM interactions, creating feedbacks that reduce reef resilience to global change.
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Affiliation(s)
- Craig E Nelson
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, Department of Oceanography, and Sea Grant College Program, School of Ocean and Earth Sciences and Technology, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA;
| | - Linda Wegley Kelly
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, USA;
| | - Andreas F Haas
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research (NIOZ), Texel, The Netherlands;
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30
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Darroch SA, Gutarra S, Masaki H, Olaru A, Gibson BM, Dunn FS, Mitchell EG, Racicot RA, Burzynski G, Rahman IA. The rangeomorph Pectinifrons abyssalis: Hydrodynamic function at the dawn of animal life. iScience 2023; 26:105989. [PMID: 36756377 PMCID: PMC9900436 DOI: 10.1016/j.isci.2023.105989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/06/2022] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
Rangeomorphs are among the oldest putative eumetazoans known from the fossil record. Establishing how they fed is thus key to understanding the structure and function of the earliest animal ecosystems. Here, we use computational fluid dynamics to test hypothesized feeding modes for the fence-like rangeomorph Pectinifrons abyssalis, comparing this to the morphologically similar extant carnivorous sponge Chondrocladia lyra. Our results reveal complex patterns of flow around P. abyssalis unlike those previously reconstructed for any other Ediacaran taxon. Comparisons with C. lyra reveal substantial differences between the two organisms, suggesting they converged on a similar fence-like morphology for different functions. We argue that the flow patterns recovered for P. abyssalis do not support either a suspension feeding or osmotrophic feeding habit. Instead, our results indicate that rangeomorph fronds may represent organs adapted for gas exchange. If correct, this interpretation could require a dramatic reinterpretation of the oldest macroscopic animals.
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Affiliation(s)
- Simon A.F. Darroch
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN 37240, USA,Evolutionary Studies Institute, Vanderbilt University, Nashville, TN 37235, USA,Senckenberg Research Institute and Natural History Museum Frankfurt, 60325 Frankfurt, Germany
| | | | - Hale Masaki
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Andrei Olaru
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Brandt M. Gibson
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN 37240, USA,Department of Chemistry and Physical Sciences, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Frances S. Dunn
- Oxford University Museum of Natural History, University of Oxford, Oxford OX1 3PW, UK
| | - Emily G. Mitchell
- Department of Zoology, Museum of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Rachel A. Racicot
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN 37240, USA,Evolutionary Studies Institute, Vanderbilt University, Nashville, TN 37235, USA,Senckenberg Research Institute and Natural History Museum Frankfurt, 60325 Frankfurt, Germany
| | - Gregory Burzynski
- Department of Biology, Fairfield University, Fairfield, CT 06824, USA
| | - Imran A. Rahman
- The Natural History Museum, London SW7 5BD, UK,Oxford University Museum of Natural History, University of Oxford, Oxford OX1 3PW, UK,Corresponding author
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Frequent Occurrence and Metabolic Versatility of Marinifilaceae Bacteria as Key Players in Organic Matter Mineralization in Global Deep Seas. mSystems 2022; 7:e0086422. [PMID: 36342154 PMCID: PMC9765461 DOI: 10.1128/msystems.00864-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Transfer of animal and plant detritus of both terrestrial and marine origins to the deep sea occurs on a global scale. Microorganisms play an important role in mineralizing them therein, but these are yet to be identified in situ. To observe key bacteria involved, we conducted long-term in situ incubation and found that members of the family Marinifilaceae (MF) occurred as some of the most predominant bacteria thriving on the new inputs of plant and animal biomasses in the deep sea in both marginal and oceanic areas. This taxon is diverse and ubiquitous in marine environments. A total of 11 MAGs belonging to MF were retrieved from metagenomic data and diverged into four subgroups in the phylogenomic tree. Based on metagenomic and metatranscriptomic analyses, we described the metabolic features and in situ metabolizing activities of different subgroups. The MF-2 subgroup, which dominates plant detritus-enriched cultures, specializes in polysaccharide degradation and lignin oxidation and has high transcriptional activities of related genes in situ. Intriguingly, members of this subgroup encode a nitrogen fixation pathway to compensate for the shortage of nitrogen sources inside the plant detritus. In contrast, other subgroups dominating the animal tissue-supported microbiomes are distinguished from MF-2 with regard to carbon and nitrogen metabolism and exhibit high transcriptional activity for proteolysis in situ. Despite these metabolic divergences of MF lineages, they show high in situ transcriptional activities for organic fermentation and anaerobic respiration (reductions of metal and/or dimethyl sulfoxide). These results highlight the role of previously unrecognized Marinifilaceae bacteria in organic matter mineralization in marine environments by coupling carbon and nitrogen cycling with metal and sulfur. IMPORTANCE Microbial mineralization of organic matter has a significant impact on the global biogeochemical cycle. This report confirms the role of Marinifilaceae in organic degradation in the oceans, with a contribution to ocean carbon cycling that has previously been underestimated. It was the dominant taxon thriving on plant and animal biomasses in our in situ incubator, as well as in whale falls and wood falls. At least 9 subgroups were revealed, and they were widely distributed in oceans globally but predominant in organic-matter-rich environments, with an average relative abundance of 8.3%. Different subgroups display a preference for the degradation of different macromolecules (polysaccharides, lignin, and protein) and adapt to their environments via special metabolic mechanisms.
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Abstract
Microorganisms dominate all ecosystems on Earth and play a key role in the turnover of organic matter. By producing enzymes, they degrade complex carbohydrates, facilitating the recycling of nutrients and controlling the carbon cycle. Despite their importance, our knowledge regarding microbial carbohydrate utilization has been limited to genome-sequenced taxa and thus heavily biased to specific groups and environments. Here, we used the Genomes from Earth's Microbiomes (GEM) catalog to describe the carbohydrate utilization potential in >7000 bacterial and archaeal taxa originating from a range of terrestrial, marine and host-associated habitats. We show that the production of carbohydrate-active enzymes (CAZymes) is phylogenetically conserved and varies significantly among microbial phyla. High numbers of carbohydrate-active enzymes were recorded in phyla known for their versatile use of carbohydrates, such as Firmicutes, Fibrobacterota, and Armatimonadota, but also phyla without cultured representatives whose carbohydrate utilization potential was so far unknown, such as KSB1, Hydrogenedentota, Sumerlaeota, and UBP3. Carbohydrate utilization potential reflected the specificity of various habitats: the richest complements of CAZymes were observed in MAGs of plant microbiomes, indicating the structural complexity of plant biopolymers. IMPORTANCE This study expanded our knowledge of the phylogenetic distribution of carbohydrate-active enzymes across prokaryotic tree of life, including new phyla where the carbohydrate-active enzymes composition have not been described until now and demonstrated the potential for carbohydrate utilization of numerous yet uncultured phyla. Profiles of carbohydrate-active enzymes are largely habitat-specific and reflect local carbohydrate availability by selecting taxa with appropriate complements of these enzymes. This information should aid in the prediction of functions in microbiomes of known taxonomic composition and helps to identify key components of habitat-specific carbohydrate pools. In addition, these findings have a high relevance for the understanding of carbohydrate utilization and carbon cycling in the environment, the process that is closely link to the carbon storage potential of Earth habitats and the production of greenhouse gasses.
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Li X, Deng Q, Zhang Z, Bai D, Liu Z, Cao X, Zhou Y, Song C. The role of sulfur cycle and enzyme activity in dissimilatory nitrate reduction processes in heterotrophic sediments. CHEMOSPHERE 2022; 308:136385. [PMID: 36096301 DOI: 10.1016/j.chemosphere.2022.136385] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 09/02/2022] [Accepted: 09/05/2022] [Indexed: 06/15/2023]
Abstract
The dissimilatory nitrate (NO3-) reduction processes (DNRPs) play an important role in regulating the nitrogen (N) balance of aquatic ecosystem. Organic carbon (OC) and sulfur are important factors that influence the DNRPs. In this study, we investigated the effects of sulfur cycle and enzyme activity on DNRPs in the natural and human-modified heterotrophic sediments. Quarterly monitoring of anaerobic ammonium oxidation, denitrification (DNF), and dissimilatory NO3- reduction to ammonium (DNRA) in sediments was conducted using 15N isotope tracing method. qPCR and high-throughput sequencing were applied to characterize the DNF and DNRA microbial abundances and communities. Results showed that instead of the OC, the glucosidase activity (GLU) was the key driver of the DNRPs. Furthermore, instead of the ratio of OC to NO3-, the GLU and the ratio of OC to sulfide (C/S) correctly indicated the partitioning of DNRPs in this study. We deduced that the sulfur reduction processes competed with the DNRPs for the available OC. In addition, the inhibitory effect of sulfide (final product of the sulfur reduction processes) on the DNRPs bacterial community were observed, which suggested a general restrictive role of the sulfur cycle in the regulation and partitioning of the DNRPs in heterotrophic sediments.
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Affiliation(s)
- Xiaowen Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, PR China.
| | - Qinghui Deng
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, PR China; Shenzhen Key Laboratory of Marine Bioresource & Eco-environmental Sciences, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, 518071, PR China.
| | - Zhimin Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, PR China.
| | - Dong Bai
- State Key Laboratory of Freshwater Ecology and Biotechnology, Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, PR China; University of Chinese Academy of Sciences, Beijing, 100039, PR China.
| | - Zhenghan Liu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, PR China; University of Chinese Academy of Sciences, Beijing, 100039, PR China.
| | - Xiuyun Cao
- State Key Laboratory of Freshwater Ecology and Biotechnology, Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, PR China.
| | - Yiyong Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, PR China.
| | - Chunlei Song
- State Key Laboratory of Freshwater Ecology and Biotechnology, Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, PR China.
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34
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Sutherland KM, Johnston DT, Hemingway JD, Wankel SD, Ward CP. Revised microbial and photochemical triple-oxygen isotope effects improve marine gross oxygen production estimates. PNAS NEXUS 2022; 1:pgac233. [PMID: 36712381 PMCID: PMC9802178 DOI: 10.1093/pnasnexus/pgac233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 10/08/2022] [Indexed: 11/05/2022]
Abstract
The biogeochemical fluxes that cycle oxygen (O2) play a critical role in regulating Earth's climate and habitability. Triple-oxygen isotope (TOI) compositions of marine dissolved O2 are considered a robust tool for tracing oxygen cycling and quantifying gross photosynthetic O2 production. This method assumes that photosynthesis, microbial respiration, and gas exchange with the atmosphere are the primary influences on dissolved O2 content, and that they have predictable, fixed isotope effects. Despite its widespread use, there are major elements of this approach that remain uncharacterized, including the TOI dynamics of respiration by marine heterotrophic bacteria and abiotic O2 sinks such as the photochemical oxidation of dissolved organic carbon (DOC). Here, we report the TOI fractionation for O2 utilization by two model marine heterotrophs and by abiotic photo-oxidation of representative terrestrial and coastal marine DOC. We demonstrate that TOI slopes associated with these processes span a significant range of the mass-dependent domain (λ = 0.499 to 0.521). A sensitivity analysis reveals that even under moderate productivity and photo-oxidation scenarios, true gross oxygen production may deviate from previous estimates by more than 20% in either direction. By considering a broader suite of oxygen cycle reactions, our findings challenge current gross oxygen production estimates and highlight several paths forward to better understanding the marine oxygen and carbon cycles.
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Affiliation(s)
| | - David T Johnston
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Jordon D Hemingway
- ETH Zürich, Geological Institute, Department of Earth Sciences, Zürich 8092, Switzerland
| | - Scott D Wankel
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
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Lloyd CC, Brown S, Balmonte JP, Hoarfrost A, Ghobrial S, Arnosti C. Particles act as ‘specialty centers’ with expanded enzymatic function throughout the water column in the western North Atlantic. Front Microbiol 2022; 13:882333. [PMID: 36246226 PMCID: PMC9553992 DOI: 10.3389/fmicb.2022.882333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
Heterotrophic bacteria initiate the degradation of high molecular weight organic matter by producing an array of extracellular enzymes to hydrolyze complex organic matter into sizes that can be taken up into the cell. These bacterial communities differ spatially and temporally in composition, and potentially also in their enzymatic complements. Previous research has shown that particle-associated bacteria can be considerably more active than bacteria in the surrounding bulk water, but most prior studies of particle-associated bacteria have been focused on the upper ocean - there are few measurements of enzymatic activities of particle-associated bacteria in the mesopelagic and bathypelagic ocean, although the bacterial communities in the deep are dependent upon degradation of particulate organic matter to fuel their metabolism. We used a broad suite of substrates to compare the glucosidase, peptidase, and polysaccharide hydrolase activities of particle-associated and unfiltered seawater microbial communities in epipelagic, mesopelagic, and bathypelagic waters across 11 stations in the western North Atlantic. We concurrently determined bacterial community composition of unfiltered seawater and of samples collected via gravity filtration (>3 μm). Overall, particle-associated bacterial communities showed a broader spectrum of enzyme activities compared with unfiltered seawater communities. These differences in enzymatic activities were greater at offshore than at coastal locations, and increased with increasing depth in the ocean. The greater differences in enzymatic function measured on particles with depth coincided with increasing differences in particle-associated community composition, suggesting that particles act as ‘specialty centers’ that are essential for degradation of organic matter even at bathypelagic depths.
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Affiliation(s)
- C. Chad Lloyd
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- *Correspondence: C. Chad Lloyd,
| | - Sarah Brown
- Environment, Ecology and Energy Program, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - John Paul Balmonte
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Biology, HADAL and Nordcee, University of Southern Denmark, Odense, Denmark
| | - Adrienne Hoarfrost
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Marine Sciences, University of Georgia, Athens, GA, United States
| | - Sherif Ghobrial
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Carol Arnosti
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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36
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Zhang W, Liu Y, Geng M, Chen R, Wang J, Xue B, Xie P, Wang J. Extracellular enzyme stoichiometry reveals carbon and nitrogen limitations closely linked to bacterial communities in China’s largest saline lake. Front Microbiol 2022; 13:1002542. [PMID: 36212873 PMCID: PMC9532593 DOI: 10.3389/fmicb.2022.1002542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 09/05/2022] [Indexed: 11/13/2022] Open
Abstract
Saline lakes possess substantial carbon storage and play essential roles in global carbon cycling. Benthic microorganisms mine and decompose sediment organic matter via extracellular enzymes to acquire limiting nutrients and thus meet their element budgets, which ultimately causes variations in sediment carbon storage. However, current knowledge about microbial nutrient limitation and the associated organic carbon changes especially in saline lake remains elusive. Therefore, we took Qinghai Lake, the largest saline lake of China, as an example to identify the patterns and drivers of microbial metabolic limitations quantified by the vector analyses of extracellular enzyme stoichiometry. Benthic microorganisms were dominantly colimited by carbon (C) and nitrogen (N). Such microbial C limitation was aggravated upon the increases in water salinity and sediment total phosphorus, which suggests that sediment C loss would be elevated when the lake water is concentrated (increasing salinity) and phosphorus becomes enriched under climate change and nutrient pollution, respectively. Microbial N limitation was predominantly intensified by water total nitrogen and inhibited by C limitation. Among the microbial drivers of extracellular enzyme investments, bacterial community structure consistently exerted significant effects on the C, N, and P cycles and microbial C and N limitations, while fungi only altered the P cycle through species richness. These findings advance our knowledge of microbial metabolic limitation in saline lakes, which will provide insights towards a better understanding of global sediment C storage dynamics under climate warming and intensified human activity.
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Affiliation(s)
- Weizhen Zhang
- Center for The Pan-Third Pole Environment, Lanzhou University, Lanzhou, China
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
| | - Yongqin Liu
- Center for The Pan-Third Pole Environment, Lanzhou University, Lanzhou, China
| | - Mengdie Geng
- Center for The Pan-Third Pole Environment, Lanzhou University, Lanzhou, China
| | - Ruirui Chen
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Jiyi Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
- College of Life Science and Technology, Harbin Normal University, Harbin, China
| | - Bin Xue
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
| | - Ping Xie
- State Key Laboratory of Plateau Ecology and Agriculture, College of Eco-Environmental Engineering, Qinghai University, Xining, China
| | - Jianjun Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
- *Correspondence: Jianjun Wang,
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37
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Qi M, Zheng C, Wu W, Yu G, Wang P. Exopolysaccharides from Marine Microbes: Source, Structure and Application. Mar Drugs 2022; 20:md20080512. [PMID: 36005515 PMCID: PMC9409974 DOI: 10.3390/md20080512] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 12/03/2022] Open
Abstract
The unique living environment of marine microorganisms endows them with the potential to produce novel chemical compounds with various biological activities. Among them, the exopolysaccharides produced by marine microbes are an important factor for them to survive in these extreme environments. Up to now, exopolysaccharides from marine microbes, especially from extremophiles, have attracted more and more attention due to their structural complexity, biodegradability, biological activities, and biocompatibility. With the development of culture and separation methods, an increasing number of novel exopolysaccharides are being found and investigated. Here, the source, structure and biological activities of exopolysaccharides, as well as their potential applications in environmental restoration fields of the last decade are summarized, indicating the commercial potential of these versatile EPS in different areas, such as food, cosmetic, and biomedical industries, and also in environmental remediation.
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Affiliation(s)
- Mingxing Qi
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China
| | - Caijuan Zheng
- Key Laboratory of Tropical Medicinal Resource Chemistry of Ministry of Education, College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158, China
- Key Laboratory of Tropical Medicinal Plant Chemistry of Hainan Province, Haikou 571158, China
| | - Wenhui Wu
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China
- Correspondence: (W.W.); (G.Y.); (P.W.); Tel.: +86-021-61900388 (W.W.); +86-0532-8203-1609 (G.Y.); +86-021-61900388 (P.W.)
| | - Guangli Yu
- Key Laboratory of Marine Drugs, Ministry of Education, Shandong Provincial Key Laboratory of Glycoscience and Glycoengineering, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266237, China
- Laboratory for Marine Drugs and Bioproducts of Qingdao Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
- Correspondence: (W.W.); (G.Y.); (P.W.); Tel.: +86-021-61900388 (W.W.); +86-0532-8203-1609 (G.Y.); +86-021-61900388 (P.W.)
| | - Peipei Wang
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China
- Correspondence: (W.W.); (G.Y.); (P.W.); Tel.: +86-021-61900388 (W.W.); +86-0532-8203-1609 (G.Y.); +86-021-61900388 (P.W.)
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38
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Manna V, Zoccarato L, Banchi E, Arnosti C, Grossart H, Celussi M. Linking lifestyle and foraging strategies of marine bacteria: selfish behaviour of particle-attached bacteria in the northern Adriatic Sea. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:549-558. [PMID: 35362215 PMCID: PMC9546125 DOI: 10.1111/1758-2229.13059] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 03/13/2022] [Accepted: 03/13/2022] [Indexed: 06/14/2023]
Abstract
Microbe-mediated enzymatic hydrolysis of organic matter entails the production of hydrolysate, the recovery of which may be more or less efficient. The selfish uptake mechanism, recently discovered, allows microbes to hydrolyze polysaccharides and take up large oligomers, which are then degraded in the periplasmic space. By minimizing the hydrolysate loss, selfish behaviour may be profitable for free-living cells dwelling in a patchy substrate landscape. However, selfish uptake seems to be tailored to algal-derived polysaccharides, abundant in organic particles, suggesting that particle-attached microbes may use this strategy. We tracked selfish polysaccharides uptake in surface microbial communities of the northeastern Mediterranean Sea, linking the occurrence of this processing mode with microbial lifestyle. Additionally, we set up fluorescently labelled polysaccharides incubations supplying phytodetritus to investigate a 'pioneer' scenario for particle-attached microbes. Under both conditions, selfish behaviour was almost exclusively carried out by particle-attached microbes, suggesting that this mechanism may represent an advantage in the race for particle exploitation. Our findings shed light on the selfish potential of particle-attached microbes, suggesting multifaceted foraging strategies exerted by particle colonizers.
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Affiliation(s)
- Vincenzo Manna
- National Institute of Oceanography and Applied Geophysics – OGSDepartment of OceanographyTriesteItaly
| | - Luca Zoccarato
- Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB)Department of Experimental LimnologyZur alten Fischerhuette 2, D‐16775 StechlinGermany
| | - Elisa Banchi
- National Institute of Oceanography and Applied Geophysics – OGSDepartment of OceanographyTriesteItaly
| | - Carol Arnosti
- University of North Carolina – Chapel HillDepartment of Earth, Marine, and Environmental SciencesChapel HillNC27599USA
| | - Hans‐Peter Grossart
- Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB)Department of Experimental LimnologyZur alten Fischerhuette 2, D‐16775 StechlinGermany
- Potsdam UniversityInstitute for Biochemistry and BiologyMaulbeeralle 2, D‐14469 PotsdamGermany
| | - Mauro Celussi
- National Institute of Oceanography and Applied Geophysics – OGSDepartment of OceanographyTriesteItaly
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39
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Giffard B, Winter S, Guidoni S, Nicolai A, Castaldini M, Cluzeau D, Coll P, Cortet J, Le Cadre E, d’Errico G, Forneck A, Gagnarli E, Griesser M, Guernion M, Lagomarsino A, Landi S, Bissonnais YL, Mania E, Mocali S, Preda C, Priori S, Reineke A, Rusch A, Schroers HJ, Simoni S, Steiner M, Temneanu E, Bacher S, Costantini EAC, Zaller J, Leyer I. Vineyard Management and Its Impacts on Soil Biodiversity, Functions, and Ecosystem Services. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.850272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Healthy soils form the basis of sustainable viticulture, where soil characteristics have a direct impact on wine quantity and quality. Soil not only provides water and nutrients to vines, but is also a living medium containing micro- and macroorganisms that perform many ecological functions and provide ecosystem services. These organisms are involved in many processes, from decomposing organic matter to providing minerals to vine roots. They also control diseases, pests, and weeds, in addition to improving the soil structure in terms of its capacity to retain water and nutrients. Related to decomposition processes, the carbon content of vineyard soils influences fertility, erosion and biogeochemical cycles, with significant implications for the global climate. However, common agricultural practices represent strong threats to biodiversity and associated ecosystem services provided by vineyard soils. As consumers increasingly consider environmental aspects in their purchase decisions, winegrowers have to adapt their vineyard management strategies, raising the demand for sustainable pest- and weed-control methods. This article presents a comprehensive review of the impacts of vineyard practices on the soil ecosystem, biodiversity, and biodiversity-based ecosystem services, and provides future prospects for sustainable viticulture.
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Karaoz U, Brodie EL. microTrait: A Toolset for a Trait-Based Representation of Microbial Genomes. FRONTIERS IN BIOINFORMATICS 2022; 2:918853. [PMID: 36304272 PMCID: PMC9580909 DOI: 10.3389/fbinf.2022.918853] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 06/20/2022] [Indexed: 11/29/2023] Open
Abstract
Remote sensing approaches have revolutionized the study of macroorganisms, allowing theories of population and community ecology to be tested across increasingly larger scales without much compromise in resolution of biological complexity. In microbial ecology, our remote window into the ecology of microorganisms is through the lens of genome sequencing. For microbial organisms, recent evidence from genomes recovered from metagenomic samples corroborate a highly complex view of their metabolic diversity and other associated traits which map into high physiological complexity. Regardless, during the first decades of this omics era, microbial ecological research has primarily focused on taxa and functional genes as ecological units, favoring breadth of coverage over resolution of biological complexity manifested as physiological diversity. Recently, the rate at which provisional draft genomes are generated has increased substantially, giving new insights into ecological processes and interactions. From a genotype perspective, the wide availability of genome-centric data requires new data synthesis approaches that place organismal genomes center stage in the study of environmental roles and functional performance. Extraction of ecologically relevant traits from microbial genomes will be essential to the future of microbial ecological research. Here, we present microTrait, a computational pipeline that infers and distills ecologically relevant traits from microbial genome sequences. microTrait maps a genome sequence into a trait space, including discrete and continuous traits, as well as simple and composite. Traits are inferred from genes and pathways representing energetic, resource acquisition, and stress tolerance mechanisms, while genome-wide signatures are used to infer composite, or life history, traits of microorganisms. This approach is extensible to any microbial habitat, although we provide initial examples of this approach with reference to soil microbiomes.
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Affiliation(s)
- Ulas Karaoz
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Eoin L. Brodie
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, United States
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Diverse Genomic Traits Differentiate Sinking-Particle-Associated versus Free-Living Microbes throughout the Oligotrophic Open Ocean Water Column. mBio 2022; 13:e0156922. [PMID: 35862780 PMCID: PMC9426571 DOI: 10.1128/mbio.01569-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Bacteria and archaea are central to the production, consumption, and remineralization of dissolved and particulate organic matter and contribute critically to carbon delivery, nutrient availability, and energy transformations in the deep ocean. To explore environmentally relevant genomic traits of sinking-particle-associated versus free-living microbes, we compared habitat-specific metagenome-assembled genomes recovered throughout the water column in the North Pacific Subtropical Gyre. The genomic traits of sinking-particle-associated versus free-living prokaryotes were compositionally, functionally, and phylogenetically distinct. Substrate-specific transporters and extracellular peptidases and carbohydrate-active enzymes were more enriched and diverse in particle-associated microbes at all depths than in free-living counterparts. These data indicate specific roles for particle-attached microbes in particle substrate hydrolysis, uptake, and remineralization. Shallow-water particle-associated microbes had elevated genomic GC content and proteome nitrogen content and reduced proteome carbon content in comparison to abyssal particle-associated microbes. An inverse trend was observed for their sympatric free-living counterparts. These different properties of attached microbes are postulated to arise in part due to elevated organic and inorganic nitrogen availability inside sinking particles. Particle-attached microbes also were enriched in genes for environmental sensing via two-component regulatory systems, and cell-cell interactions via extracellular secretion systems, reflecting their surface-adapted lifestyles. Finally, particle-attached bacteria had greater predicted maximal growth efficiencies than free-living bacterioplankton at all depths. All of these particle-associated specific genomic and proteomic features appear to be driven by microhabitat-specific elevated nutrient and energy availability as well as surface-associated competitive and synergistic ecological interactions. Although some of these characteristics have been previously postulated or observed individually, we report them together here in aggregate via direct comparisons of cooccurring free-living and sinking-particle-attached microbial genomes from the open ocean.
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Role of Staphylococcus agnetis and Staphylococcus hyicus in the Pathogenesis of Buffalo Fly Skin Lesions in Cattle. Microbiol Spectr 2022; 10:e0087322. [PMID: 35863026 PMCID: PMC9430782 DOI: 10.1128/spectrum.00873-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Buffalo flies (Haematobia irritansexigua) are hematophagous ectoparasites of cattle causing production and welfare impacts in northern Australian herds. Skin lesions associated with buffalo fly infestation and Stephanofilaria nematode infection are manifested as focal dermatitis or ulcerated areas, most commonly on the medial canthus of the eye, along the lateral and ventral neck, and on the abdomen of cattle. For closely related horn flies (Haematobia irritans irritans), Staphylococcus aureus has been suggested as a contributing factor in the development of lesions. To investigate the potential role of bacterial infection in the pathogenesis of buffalo fly lesions, swabs were taken from lesions and normal skin, and bacteria were also isolated from surface washings of buffalo flies and surface-sterilized homogenized flies. Bacterial identification was conducted by matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) and strain typing by repetitive sequence-based PCR (rep-PCR) and DNA sequencing to determine species similarity and virulence factors. Of 50 bacterial isolates collected from lesions, 38 were identified as Staphylococcus agnetis and 12 as Staphylococcus hyicus, whereas four isolates from normal skin were S. hyicus and one was Mammaliicoccus sciuri. Of the Staphylococcus isolates isolated from buffalo flies, five were identified as S. agnetis and three as S. hyicus. Fifty percent of the buffalo fly isolates had rep-PCR genotypic patterns identical to those of the lesion isolates. Genome sequencing of 16 S. agnetis and four S. hyicus isolates revealed closely similar virulence factor profiles, with all isolates possessing exfoliative toxin A and C genes. The findings from this study suggest the involvement of S. agnetis and S. hyicus in buffalo fly lesion pathogenesis. This should be taken into account in the development of effective treatment and control strategies for lesions. IMPORTANCE Skin lesions in cattle associated with feeding by Haematobia fly species are a significant welfare issue in Australia, North and South America, and Europe. The development of these lesions has been attributed to a number of causal factors, but the exact etiology and pathogenesis were unclear. This study characterized Staphylococcus agnetis and Staphylococcus hyicus strains from cattle skin lesions and in vector flies and demonstrated their role in the pathogenesis of these lesions. These findings will aid the development of targeted and more effective treatment and control strategies for lesions associated with fly infestation in cattle.
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Yun J, Jung JY, Kwon MJ, Seo J, Nam S, Lee YK, Kang H. Temporal Variations Rather than Long-Term Warming Control Extracellular Enzyme Activities and Microbial Community Structures in the High Arctic Soil. MICROBIAL ECOLOGY 2022; 84:168-181. [PMID: 34498119 DOI: 10.1007/s00248-021-01859-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 09/02/2021] [Indexed: 06/13/2023]
Abstract
In Arctic soils, warming accelerates decomposition of organic matter and increases emission of greenhouse gases (GHGs), contributing to a positive feedback to climate change. Although microorganisms play a key role in the processes between decomposition of organic matter and GHGs emission, the effects of warming on temporal responses of microbial activity are still elusive. In this study, treatments of warming and precipitation were conducted from 2012 to 2018 in Cambridge Bay, Canada. Soils of organic and mineral layers were collected monthly from June to September in 2018 and analyzed for extracellular enzyme activities and bacterial community structures. The activity of hydrolases was the highest in June and decreased thereafter over summer in both organic and mineral layers. Bacterial community structures changed gradually over summer, and the responses were distinct depending on soil layers and environmental factors; water content and soil temperature affected the shift of bacterial community structures in both layers, whereas bacterial abundance, dissolved organic carbon, and inorganic nitrogen did so in the organic layer only. The activity of hydrolases and bacterial community structures did not differ significantly among treatments but among months. Our results demonstrate that temporal variations may control extracellular enzyme activities and microbial community structure rather than the small effect of warming over a long period in high Arctic soil. Although the effects of the treatments on microbial activity were minor, our study provides insight that microbial activity may increase due to an increase in carbon availability, if the growing season is prolonged in the Arctic.
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Affiliation(s)
- Jeongeun Yun
- School of Civil and Environmental Engineering, Yonsei University, Seoul, 03722, Korea
| | - Ji Young Jung
- Korea Polar Research Institute, Incheon, 21990, Korea
| | - Min Jung Kwon
- Laboratoire Des Sciences du Climat Et de I'Environnement, LSCE, 91191, Gif sur Yvette, France
| | - Juyoung Seo
- School of Civil and Environmental Engineering, Yonsei University, Seoul, 03722, Korea
| | - Sungjin Nam
- Korea Polar Research Institute, Incheon, 21990, Korea
| | - Yoo Kyung Lee
- Korea Polar Research Institute, Incheon, 21990, Korea
| | - Hojeong Kang
- School of Civil and Environmental Engineering, Yonsei University, Seoul, 03722, Korea.
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Wang J, Guo X, Li Y, Song G, Zhao L. Understanding the Variation of Bacteria in Response to Summertime Oxygen Depletion in Water Column of Bohai Sea. Front Microbiol 2022; 13:890973. [PMID: 35756048 PMCID: PMC9221365 DOI: 10.3389/fmicb.2022.890973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/05/2022] [Indexed: 11/14/2022] Open
Abstract
Aiming to reveal the variation in bacteria community under oxygen depletion formed every summer in water column of central Bohai Sea, a time-scenario sampling from June to August in 2018 at a 20-day interval along one inshore-offshore transect was settled. Water samples were collected at the surface, middle, and bottom layer and then analyzed by high-throughput sequencing targeting both 16S rRNA and nosZ genes. Compared to the surface and middle water, oxygen depletion occurred at bottom layer in August. In top two layers, Cyanobacteria dominated the bacterial community, whereas heterotrophic bacteria became dominant in bottom water of Bohai Sea. Based on the time scenario, distinct community separation was observed before (June and July) and after (August) oxygen depletion (p = 0.003). Vertically, strict stratification of nosZ gene was stably formed along 3 sampling layers. As a response to oxygen depletion, the diversity indices of both total bacteria (16S rRNA) and nosZ gene-encoded denitrification bacteria all increased, which indicated the intense potential of nitrogen lose when oxygen depleted. Dissolved oxygen (DO) was the key impacting factor on the community composition of total bacteria in June, whereas nutrients together with DO play the important roles in August for both total and denitrifying bacteria. The biotic impact was revealed further by strong correlations which showed between Cyanobacteria and heterotrophic bacteria in June from co-occurrence network analysis, which became weak in August when DO was depleted. This study discovered the variation in bacteria community in oxygen-depleted water with further effort to understand the potential role of denitrifying bacteria under oxygen depletion in Bohai Sea for the first time, which provided insights into the microbial response to the world-wide expanding oxygen depletion and their contributions in the ocean nitrogen cycling.
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Affiliation(s)
- Jing Wang
- Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, Tianjin Normal University, Tianjin, China
| | - Xiaoxiao Guo
- Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, Tianjin Normal University, Tianjin, China
| | - Yanying Li
- Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, Tianjin Normal University, Tianjin, China
| | - Guisheng Song
- School of Marine Science and Technology, Tianjin University, Tianjin, China
| | - Liang Zhao
- College of Marine and Environmental Sciences, Tianjin University of Science and Technology, Tianjin, China
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Liu Y, Wang X, Sun J. Bacterial Transformation and Processing of Diatom-Derived Organic Matter: A Case Study for Skeletonema dohrnii. Front Microbiol 2022; 13:840564. [PMID: 35572715 PMCID: PMC9096949 DOI: 10.3389/fmicb.2022.840564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 03/25/2022] [Indexed: 11/13/2022] Open
Abstract
Bacterial transformation and processing of phytoplankton-derived organic matter are extremely important for the formation of ubiquitous organic matter (OM) in aquatic ecosystems. Heterotrophic bacteria convert OM into biomass and recycle inorganic components, contributing to the production of microbial food webs. While phytoplankton-derived organic matter is commonly studied, the transformation and processing of dissolved OM (DOM) and lysate OM (LOM) by culturable epiphytic bacteria remains poorly understood. In this study, cultivable epiphytic bacteria from the marine diatom, Skeletonema dohrnii, were isolated, purified, and identified. Three bacteria, Roseobacteria sp., Marinobacter sp., and Bacillus sp., were selected to study the transformation and processing of S. dohrnii-derived DOM and LOM using excitation-emission matrix (EEM) fluorescence methods, and bacterial abundance, dissolved organic carbon (DOC) concentration, and transparent exopolymer particle (TEP) content were measured. Meanwhile, the bacterial transformation of DOM and LOM was further evaluated by the fluorescence index, biological index, β/α, and humification index. The primary fluorophores, peak A (humic-like), peak C (humic-like), peak M (humic-like), peak B (protein-like), and peak T (tryptophan-like), were present in the sample. The fluorescence of DOM and LOM was dominated by protein-like signal that became increasingly humic-like over time, suggesting that more complex molecules (e.g., recalcitrant OM) are being produced. The fluorescence of DOM and LOM was dominated by a protein-like signal that became increasingly humic-like over time, suggesting that epiphytic bacteria produced more complex molecules. Results showed that the bacteria utilized LOM more rapidly than DOM. While the three bacteria transformed OM to different degrees, all were able to facilitate microbial reprocessing of OM into refractory OM.
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Affiliation(s)
- Yang Liu
- Institute of Marine Science and Technology, Shandong University, Qingdao, China.,Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, China
| | - Xueru Wang
- Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, China
| | - Jun Sun
- Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, China.,College of Marine Science and Technology, China University of Geosciences, Wuhan, China.,State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
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Liu S, Longnecker K, Kujawinski EB, Vergin K, Bolaños LM, Giovannoni SJ, Parsons R, Opalk K, Halewood E, Hansell DA, Johnson R, Curry R, Carlson CA. Linkages Among Dissolved Organic Matter Export, Dissolved Metabolites, and Associated Microbial Community Structure Response in the Northwestern Sargasso Sea on a Seasonal Scale. Front Microbiol 2022; 13:833252. [PMID: 35350629 PMCID: PMC8957919 DOI: 10.3389/fmicb.2022.833252] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 01/31/2022] [Indexed: 01/04/2023] Open
Abstract
Deep convective mixing of dissolved and suspended organic matter from the surface to depth can represent an important export pathway of the biological carbon pump. The seasonally oligotrophic Sargasso Sea experiences annual winter convective mixing to as deep as 300 m, providing a unique model system to examine dissolved organic matter (DOM) export and its subsequent compositional transformation by microbial oxidation. We analyzed biogeochemical and microbial parameters collected from the northwestern Sargasso Sea, including bulk dissolved organic carbon (DOC), total dissolved amino acids (TDAA), dissolved metabolites, bacterial abundance and production, and bacterial community structure, to assess the fate and compositional transformation of DOM by microbes on a seasonal time-scale in 2016–2017. DOM dynamics at the Bermuda Atlantic Time-series Study site followed a general annual trend of DOC accumulation in the surface during stratified periods followed by downward flux during winter convective mixing. Changes in the amino acid concentrations and compositions provide useful indices of diagenetic alteration of DOM. TDAA concentrations and degradation indices increased in the mesopelagic zone during mixing, indicating the export of a relatively less diagenetically altered (i.e., more labile) DOM. During periods of deep mixing, a unique subset of dissolved metabolites, such as amino acids, vitamins, and benzoic acids, was produced or lost. DOM export and compositional change were accompanied by mesopelagic bacterial growth and response of specific bacterial lineages in the SAR11, SAR202, and SAR86 clades, Acidimicrobiales, and Flavobacteria, during and shortly following deep mixing. Complementary DOM biogeochemistry and microbial measurements revealed seasonal changes in DOM composition and diagenetic state, highlighting microbial alteration of the quantity and quality of DOM in the ocean.
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Affiliation(s)
- Shuting Liu
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Krista Longnecker
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Elizabeth B Kujawinski
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Kevin Vergin
- Microbial DNA Analytics, Phoenix, OR, United States
| | - Luis M Bolaños
- School of Biosciences, University of Exeter, Exeter, United Kingdom.,Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Stephen J Giovannoni
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Rachel Parsons
- Bermuda Institute of Ocean Sciences, Saint George's, Bermuda
| | - Keri Opalk
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Elisa Halewood
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Dennis A Hansell
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States
| | - Rod Johnson
- Bermuda Institute of Ocean Sciences, Saint George's, Bermuda
| | - Ruth Curry
- Bermuda Institute of Ocean Sciences, Saint George's, Bermuda
| | - Craig A Carlson
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
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Chen J, Zang Y, Yang Z, Qu T, Sun T, Liang S, Zhu M, Wang Y, Tang X. Composition and Functional Diversity of Epiphytic Bacterial and Fungal Communities on Marine Macrophytes in an Intertidal Zone. Front Microbiol 2022; 13:839465. [PMID: 35369473 PMCID: PMC8972133 DOI: 10.3389/fmicb.2022.839465] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
Marine macrophytes (seagrasses and macroalgae) and their epiphytic microorganisms play an important role in the ecological and biochemical processes of coastal oceans. However, simultaneous comparative studies on the biodiversity and functions of epiphytic bacteria and fungi associated with marine macrophytes have not been conducted. In this study, high-throughput sequencing technology was used to describe the epiphytic bacterial and fungal communities of 11 common macroalgae and 2 seagrasses from an intertidal zone of northern China and compare them with seawater communities. The results showed that Proteobacteria and Bacteroidota were the dominant bacterial phyla in marine macrophytes, whereas Ascomycota, Chytridiomycota, and Basidiomycota were the dominant fungal phyla. The alpha diversity of the bacterial and fungal communities in seagrasses was the highest of all macrophyte samples. This may have been related to their ability to recruit microorganisms from multiple sources. Host phylogeny may influence bacterial community structure, and geographical differences may influence fungal community structure. The FAPROTAX data indicated that C metabolic microbes were enriched in marine macrophytes, while the FUNGuild data indicated that undefined saprotroph, which participated in organic matter degradation, were also enriched in marine macrophytes. These findings provide a theoretical basis regarding the epiphytic microorganisms of macrophytes and may offer new insights to support the improved ecological restoration of seagrass and macroalgae beds.
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Affiliation(s)
- Jun Chen
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Yu Zang
- Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China
| | - Zhibo Yang
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Tongfei Qu
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Tao Sun
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Shuo Liang
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Meiling Zhu
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Ying Wang
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xuexi Tang
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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Microbial Community Structure and Ecological Networks during Simulation of Diatom Sinking. Microorganisms 2022; 10:microorganisms10030639. [PMID: 35336213 PMCID: PMC8949005 DOI: 10.3390/microorganisms10030639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/10/2022] [Accepted: 03/11/2022] [Indexed: 11/17/2022] Open
Abstract
Microbial-mediated utilization of particulate organic matter (POM) during its downward transport from the surface to the deep ocean constitutes a critical component of the global ocean carbon cycle. However, it remains unclear as to how high hydrostatic pressure (HHP) and low temperature (LT) with the sinking particles affects community structure and network interactions of the particle-attached microorganisms (PAM) and those free-living microorganisms (FLM) in the surrounding water. In this study, we investigated microbial succession and network interactions in experiments simulating POM sinking in the ocean. Diatom-derived 13C- and 12C-labeled POM were used to incubate surface water microbial communities from the East China Sea (ECS) under pressure (temperature) of 0.1 (25 °C), 20 (4 °C), and 40 (4 °C) MPa (megapascal). Our results show that the diversity and species richness of the PAM and FLM communities decreased significantly with HHP and LT. Microbial community analysis indicated an increase in the relative abundance of Bacteroidetes at high pressure (40 MPa), mostly at the expense of Gammaproteobacteria, Alphaproteobacteria, and Gracilibacteria at atmospheric pressure. Hydrostatic pressure and temperature affected lifestyle preferences between particle-attached (PA) and free-living (FL) microbes. Ecological network analysis showed that HHP and LT enhanced microbial network interactions and resulted in higher vulnerability to networks of the PAM communities and more resilience of those of the FLM communities. Most interestingly, the PAM communities occupied most of the module hubs of the networks, whereas the FLM communities mainly served as connectors of the modules, suggesting their different ecological roles of the two groups of microbes. These results provided novel insights into how HHP and LT affected microbial community dynamics, ecological networks during POM sinking, and the implications for carbon cycling in the ocean.
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Kulshreshtha G, D’Alba L, Dunn IC, Rehault-Godbert S, Rodriguez-Navarro AB, Hincke MT. Properties, Genetics and Innate Immune Function of the Cuticle in Egg-Laying Species. Front Immunol 2022; 13:838525. [PMID: 35281050 PMCID: PMC8914949 DOI: 10.3389/fimmu.2022.838525] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/31/2022] [Indexed: 01/13/2023] Open
Abstract
Cleidoic eggs possess very efficient and orchestrated systems to protect the embryo from external microbes until hatch. The cuticle is a proteinaceous layer on the shell surface in many bird and some reptile species. An intact cuticle forms a pore plug to occlude respiratory pores and is an effective physical and chemical barrier against microbial penetration. The interior of the egg is assumed to be normally sterile, while the outer eggshell cuticle hosts microbes. The diversity of the eggshell microbiome is derived from both maternal microbiota and those of the nesting environment. The surface characteristics of the egg, outer moisture layer and the presence of antimicrobial molecules composing the cuticle dictate constituents of the microbial communities on the eggshell surface. The avian cuticle affects eggshell wettability, water vapor conductance and regulates ultraviolet reflectance in various ground-nesting species; moreover, its composition, thickness and degree of coverage are dependent on species, hen age, and physiological stressors. Studies in domestic avian species have demonstrated that changes in the cuticle affect the food safety of eggs with respect to the risk of contamination by bacterial pathogens such as Salmonella and Escherichia coli. Moreover, preventing contamination of internal egg components is crucial to optimize hatching success in bird species. In chickens there is moderate heritability (38%) of cuticle deposition with a potential for genetic improvement. However, much less is known about other bird or reptile cuticles. This review synthesizes current knowledge of eggshell cuticle and provides insight into its evolution in the clade reptilia. The origin, composition and regulation of the eggshell microbiome and the potential function of the cuticle as the first barrier of egg defense are discussed in detail. We evaluate how changes in the cuticle affect the food safety of table eggs and vertical transmission of pathogens in the production chain with respect to the risk of contamination. Thus, this review provides insight into the physiological and microbiological characteristics of eggshell cuticle in relation to its protective function (innate immunity) in egg-laying birds and reptiles.
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Affiliation(s)
- Garima Kulshreshtha
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Liliana D’Alba
- Evolutionary Ecology, Naturalis Biodiversity Center, Leiden, Netherlands
| | - Ian C. Dunn
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | | | | | - Maxwell T. Hincke
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Innovation in Medical Education, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
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Liu Y, Wang X, Sun J. Transformations of Diatom-Derived Dissolved Organic Matter by Bacillus pumilus Under Warming and Acidification Conditions. Front Microbiol 2022; 13:833670. [PMID: 35283861 PMCID: PMC8914222 DOI: 10.3389/fmicb.2022.833670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 01/10/2022] [Indexed: 01/08/2023] Open
Abstract
Heterotrophic bacteria are assumed to play an important role in processing of phytoplankton-derived dissolved organic matter (DOM). Although the algae-derived organic matter is commonly studied, the transformation and processing of DOM by epiphytic bacteria for phytoplankton have rarely been investigated, especially under warming and acidification. In this study, Bacillus pumilus is used to explore the ecologically important marine diatom Skeletonema dohrnii-derived DOM under different conditions (temperature, 27°C and 31°C; pCO2, 400 and 1,000 ppm), utilizing fluorescence excitation-emission matrix (EEM) combined with parallel factor analysis (EEM-PARAFAC). Fluorescence regional integration and the peak selecting method are used to generate B, T, N, A, M, and C peaks in the EEM fluorescence spectroscopy. The main known fluorophores including that protein-like components (peaks B and T), unknown components (peak N), and humic-like component (peaks A, M, and C). Our experimental results showed that under higher temperature and pressure of CO2 (pCO2) conditions, S. dohrnii-derived DOM fluorescence was dominated by a protein-like signal that slower waning throughout the experiment, becoming an increasingly humic-like substance, implying that processing by the epiphytic bacteria (B. pumilus) produced more complex molecules. In addition, spectroscopic indices (e.g., fluorescence index, biological index, freshness index β/α, and humification index) were changed in varying degrees. This study reveals and confirms the direct participation of heterotrophic bacteria in the transformation and generation of algae-derived DOM in the laboratory, underlining the influence of global warming and ocean acidification on this process.
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Affiliation(s)
- Yang Liu
- Institute of Marine Science and Technology, Shandong University, Qingdao, China
- Research Center for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, China
| | - Xueru Wang
- Research Center for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, China
| | - Jun Sun
- Research Center for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, China
- College of Marine Science and Technology, China University of Geosciences, Wuhan, China
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
- *Correspondence: Jun Sun,
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