1
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Vishal CR, Gauns MU, Pratihary AK, Sadaiappan B. Unprecedented warming impacts on phytoplankton and special emphasis on diatom-diazotroph associations in the oligotrophic waters of the Eastern Arabian sea. MARINE ENVIRONMENTAL RESEARCH 2025; 207:107038. [PMID: 40048810 DOI: 10.1016/j.marenvres.2025.107038] [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: 07/20/2024] [Revised: 11/17/2024] [Accepted: 02/25/2025] [Indexed: 04/01/2025]
Abstract
The impact of anomalous warming on the phytoplankton dynamics in the euphotic zone (0-60 m depth) of the eastern Arabian Sea (EAS) during the southwest monsoon (SWM-2020) was investigated along the 68°E transect from 8°N to 21°N. During SWM-2020, sea surface temperatures (SSTs) along the transect exceeded 28 °C, with temperatures of ∼29-30 °C recorded in the North of the Findlater Jet Axis (NFJA). The active Findlater Jet (FJ) modulated the thermocline, causing shallower thermocline in the North EAS (NEAS, 16-21°N) and deeper thermocline in the South EAS (SEAS, 8-15°N). The increased stratification due to warming reduced the vertical mixing and exacerbated the oligotrophic condition within the MLDs in the NEAS. High dissolved inorganic silicate and phosphorous with low nitrate concentrations favouring dinoflagellates and diatom-diazotroph associations (DDAs) within the MLDs, particularly in the NEAS. In the NEAS, heterocystous cyanobacteria Richelia was abundant as free-living and in endosymbiosis with Rhizosolenia and Hemiaulus, while coccoid cells of Crocosphaera, symbiotic with Climacodium sp., thrived in both SEAS and NEAS indicating a critical role of dissolved iron in distribution of DDAs. DDAs were abundant in subsurface waters (25-40 m) and rare or absent within the nutricline and subsurface chlorophyll maximum (SCM, 40-60 m depths). High dissolved ammonium concentration in the NEAS indicated that N2 fixed by DDAs could be supplied into N-limited waters. A high abundance of unhealthy and moribund host-symbiotic stages suggests extreme warming, and shallower nitracline could harm DDAs in the EAS. This study highlights the importance of DDAs in the EAS, which remains poorly understood, and whose underestimation in N2 and C fixation can impact the regional nitrogen and carbon budgets.
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Affiliation(s)
- Chazhikulam Rajan Vishal
- CSIR-National Institute of Oceanography, Goa, India- 403004; School of Earth, Ocean and Atmospheric Sciences (SEOAS) - Department of Marine Science, Goa University, Taleigao Plateau, India- 403206
| | | | | | - Balamurugan Sadaiappan
- Department of Biology, United Arab Emirates University, Al Ain 971, United Arab Emirates
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2
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Helmann JD. Metals in Motion: Understanding Labile Metal Pools in Bacteria. Biochemistry 2025; 64:329-345. [PMID: 39755956 PMCID: PMC11755726 DOI: 10.1021/acs.biochem.4c00726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2024] [Revised: 12/02/2024] [Accepted: 12/13/2024] [Indexed: 01/07/2025]
Abstract
Metal ions are essential for all life. In microbial cells, potassium (K+) is the most abundant cation and plays a key role in maintaining osmotic balance. Magnesium (Mg2+) is the dominant divalent cation and is required for nucleic acid structure and as an enzyme cofactor. Microbes typically require the transition metals manganese (Mn), iron (Fe), copper (Cu), and zinc (Zn), although the precise set of metal ions needed to sustain life is variable. Intracellular metal pools can be conceptualized as a chemically complex mixture of rapidly exchanging (labile) ions, complemented by those reservoirs that exchange slowly relative to cell metabolism (sequestered). Labile metal pools are buffered by transient interactions with anionic metabolites and macromolecules, with the ribosome playing a major role. Sequestered metal pools include many metalloproteins, cofactors, and storage depots, with some pools redeployed upon metal depletion. Here, I review the size, composition, and dynamics of intracellular metal pools and highlight the major gaps in understanding.
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Affiliation(s)
- John D. Helmann
- Department of Microbiology, Cornell University, Ithaca, New York 14853-8101, United States
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3
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Caille C, Duhamel S, Latifi A, Rabouille S. Adaptive Responses of Cyanobacteria to Phosphate Limitation: A Focus on Marine Diazotrophs. Environ Microbiol 2024; 26:e70023. [PMID: 39714117 DOI: 10.1111/1462-2920.70023] [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: 05/14/2024] [Revised: 11/08/2024] [Accepted: 12/03/2024] [Indexed: 12/24/2024]
Abstract
Phosphorus is an essential component of numerous macromolecules and is vital for life. Its availability significantly influences primary production, particularly in oligotrophic environments. Marine diazotrophic cyanobacteria, which play key roles in biogeochemical cycles through nitrogen fixation (N2 fixation), have adapted to thrive in phosphate (Pi)-poor areas. However, the molecular mechanisms that facilitate their adaptation to such conditions remain incompletely understood. Bacteria have evolved various strategies to cope with Pi limitation, including detecting Pi availability, utilising high-affinity Pi transporters, and hydrolyzing dissolved organic phosphorus (DOP) with various enzymes. This review synthesises current knowledge regarding how cyanobacteria adapt to Pi scarcity, with particular emphasis on subtropical marine free-living diazotrophs and their ability to utilise diverse DOP molecules. Omics approaches, such as (meta)genomics and (meta)transcriptomics, reveal the resilience of marine diazotrophs in the face of Pi scarcity and highlight the need for further research into their molecular adaptive strategies. Adaptation to Pi limitation is often intertwined with the broader response of cyanobacteria to multiple limitations and stresses. This underscores the importance of understanding Pi adaptation to assess the ecological resilience of these crucial microorganisms in dynamic environments, particularly in the context of global climate change.
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Affiliation(s)
- Chloé Caille
- CNRS, Sorbonne Université, UMR 7621, Laboratoire d'Océanographie Microbienne (LOMIC), Banyuls sur mer, France
- Aix Marseille Univ, CNRS, Laboratoire de Chimie Bactérienne LCB, IMM, Marseille, France
| | - Solange Duhamel
- Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA
| | - Amel Latifi
- Aix Marseille Univ, CNRS, Laboratoire de Chimie Bactérienne LCB, IMM, Marseille, France
| | - Sophie Rabouille
- CNRS, Sorbonne Université, UMR 7621, Laboratoire d'Océanographie Microbienne (LOMIC), Banyuls sur mer, France
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4
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Rose SA, Robicheau BM, Tolman J, Fonseca-Batista D, Rowland E, Desai D, Ratten JM, Kantor EJH, Comeau AM, Langille MG, Jerlström-Hultqvist J, Devred E, Sarthou G, Bertrand EM, LaRoche J. Nitrogen fixation in the widely distributed marine γ-proteobacterial diazotroph Candidatus Thalassolituus haligoni. SCIENCE ADVANCES 2024; 10:eadn1476. [PMID: 39083619 PMCID: PMC11290528 DOI: 10.1126/sciadv.adn1476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 06/25/2024] [Indexed: 08/02/2024]
Abstract
The high diversity and global distribution of heterotrophic bacterial diazotrophs (HBDs) in the ocean has recently become apparent. However, understanding the role these largely uncultured microorganisms play in marine N2 fixation poses a challenge due to their undefined growth requirements and the complex regulation of the nitrogenase enzyme. We isolated and characterized Candidatus Thalassolituus haligoni, a member of a widely distributed clade of HBD belonging to the Oceanospirillales. Analysis of its nifH gene via amplicon sequencing revealed the extensive distribution of Cand. T. haligoni across the Pacific, Atlantic, and Arctic Oceans. Pangenome analysis indicates that the isolate shares >99% identity with an uncultured metagenome-assembled genome called Arc-Gamma-03, recently recovered from the Arctic Ocean. Through combined genomic, proteomic, and physiological approaches, we confirmed that the isolate fixes N2 gas. However, the mechanisms governing nitrogenase regulation in Cand. T. haligoni remain unclear. We propose Cand. T. haligoni as a globally distributed, cultured HBD model species within this understudied clade of Oceanospirillales.
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Affiliation(s)
- Sonja A. Rose
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Brent M. Robicheau
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jennifer Tolman
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Debany Fonseca-Batista
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Oceanography, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Elden Rowland
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Dhwani Desai
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
- Integrated Microbiome Resource (IMR) and Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jenni-Marie Ratten
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Ella Joy H. Kantor
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - André M. Comeau
- Integrated Microbiome Resource (IMR) and Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Morgan G.I. Langille
- Integrated Microbiome Resource (IMR) and Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
| | | | - Emmanuel Devred
- Fisheries and Oceans Canada, Bedford Institute of Oceanography, Halifax, Nova Scotia, Canada
| | | | - Erin M. Bertrand
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Julie LaRoche
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
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5
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Calvanese M, D’Angelo C, Tutino ML, Lauro C. Whole-Cell Biosensor for Iron Monitoring as a Potential Tool for Safeguarding Biodiversity in Polar Marine Environments. Mar Drugs 2024; 22:299. [PMID: 39057408 PMCID: PMC11277574 DOI: 10.3390/md22070299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/05/2024] [Accepted: 06/24/2024] [Indexed: 07/28/2024] Open
Abstract
Iron is a key micronutrient essential for various essential biological processes. As a consequence, alteration in iron concentration in seawater can deeply influence marine biodiversity. In polar marine environments, where environmental conditions are characterized by low temperatures, the role of iron becomes particularly significant. While iron limitation can negatively influence primary production and nutrient cycling, excessive iron concentrations can lead to harmful algal blooms and oxygen depletion. Furthermore, the growth of certain phytoplankton species can be increased in high-iron-content environments, resulting in altered balance in the marine food web and reduced biodiversity. Although many chemical/physical methods are established for inorganic iron quantification, the determination of the bio-available iron in seawater samples is more suitably carried out using marine microorganisms as biosensors. Despite existing challenges, whole-cell biosensors offer other advantages, such as real-time detection, cost-effectiveness, and ease of manipulation, making them promising tools for monitoring environmental iron levels in polar marine ecosystems. In this review, we discuss fundamental biosensor designs and assemblies, arranging host features, transcription factors, reporter proteins, and detection methods. The progress in the genetic manipulation of iron-responsive regulatory and reporter modules is also addressed to the optimization of the biosensor performance, focusing on the improvement of sensitivity and specificity.
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Affiliation(s)
- Marzia Calvanese
- Department of Chemical Sciences, University of Naples “Federico II”, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy; (M.C.); (C.D.); (M.L.T.)
- Istituto Nazionale Biostrutture e Biosistemi (I.N.B.B), Viale Medaglie D’Oro 305, 00136 Roma, Italy
| | - Caterina D’Angelo
- Department of Chemical Sciences, University of Naples “Federico II”, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy; (M.C.); (C.D.); (M.L.T.)
| | - Maria Luisa Tutino
- Department of Chemical Sciences, University of Naples “Federico II”, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy; (M.C.); (C.D.); (M.L.T.)
- Istituto Nazionale Biostrutture e Biosistemi (I.N.B.B), Viale Medaglie D’Oro 305, 00136 Roma, Italy
| | - Concetta Lauro
- Department of Chemical Sciences, University of Naples “Federico II”, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy; (M.C.); (C.D.); (M.L.T.)
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6
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Masuda T, Mareš J, Shiozaki T, Inomura K, Fujiwara A, Prášil O. Crocosphaera watsonii - A widespread nitrogen-fixing unicellular marine cyanobacterium. JOURNAL OF PHYCOLOGY 2024; 60:604-620. [PMID: 38551849 DOI: 10.1111/jpy.13450] [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: 05/05/2023] [Revised: 12/14/2023] [Accepted: 02/08/2024] [Indexed: 06/12/2024]
Abstract
Crocosphaera watsonii is a unicellular N2-fixing (diazotrophic) cyanobacterium observed in tropical and subtropical oligotrophic oceans. As a diazotroph, it can be a source of bioavailable nitrogen (N) to the microbial community in N-limited environments, and this may fuel primary production in the regions where it occurs. Crocosphaera watsonii has been the subject of intense study, both in culture and in field populations. Here, we summarize the current understanding of the phylogenetic and physiological diversity of C. watsonii, its distribution, and its ecological niche. Analysis of the relationships among the individual Crocosphaera species and related free-living and symbiotic lineages of diazotrophs based on the nifH gene have shown that the C. watsonii group holds a basal position and that its sequence is more similar to Rippkaea and Zehria than to other Crocosphaera species. This finding warrants further scrutiny to determine if the placement is related to a horizontal gene transfer event. Here, the nifH UCYN-B gene copy number from a recent synthesis effort was used as a proxy for relative C. watsonii abundance to examine patterns of C. watsonii distribution as a function of environmental factors, like iron and phosphorus concentration, and complimented with a synthesis of C. watsonii physiology. Furthermore, we have summarized the current knowledge of C. watsonii with regards to N2 fixation, photosynthesis, and quantitative modeling of physiology. Because N availability can limit primary production, C. watsonii is widely recognized for its importance to carbon and N cycling in ocean ecosystems, and we conclude this review by highlighting important topics for further research on this important species.
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Affiliation(s)
- Takako Masuda
- Institute of Microbiology, The Czech Academy of Sciences, Třeboň, Czech Republic
- Japan Fisheries Research and Education Agency, Shiogama, Miyagi, Japan
| | - Jan Mareš
- Institute of Microbiology, The Czech Academy of Sciences, Třeboň, Czech Republic
- Institute of Hydrobiology, Biology Centre, The Czech Academy of Sciences, České Budejovice, Czech Republic
| | - Takuhei Shiozaki
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan
| | - Keisuke Inomura
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA
| | - Amane Fujiwara
- Research Institute for Global Change, JAMSTEC, Yokosuka, Japan
| | - Ondřej Prášil
- Institute of Microbiology, The Czech Academy of Sciences, Třeboň, Czech Republic
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7
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Coale TH, Loconte V, Turk-Kubo KA, Vanslembrouck B, Mak WKE, Cheung S, Ekman A, Chen JH, Hagino K, Takano Y, Nishimura T, Adachi M, Le Gros M, Larabell C, Zehr JP. Nitrogen-fixing organelle in a marine alga. Science 2024; 384:217-222. [PMID: 38603509 DOI: 10.1126/science.adk1075] [Citation(s) in RCA: 47] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 02/22/2024] [Indexed: 04/13/2024]
Abstract
Symbiotic interactions were key to the evolution of chloroplast and mitochondria organelles, which mediate carbon and energy metabolism in eukaryotes. Biological nitrogen fixation, the reduction of abundant atmospheric nitrogen gas (N2) to biologically available ammonia, is a key metabolic process performed exclusively by prokaryotes. Candidatus Atelocyanobacterium thalassa, or UCYN-A, is a metabolically streamlined N2-fixing cyanobacterium previously reported to be an endosymbiont of a marine unicellular alga. Here we show that UCYN-A has been tightly integrated into algal cell architecture and organellar division and that it imports proteins encoded by the algal genome. These are characteristics of organelles and show that UCYN-A has evolved beyond endosymbiosis and functions as an early evolutionary stage N2-fixing organelle, or "nitroplast."
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Affiliation(s)
- Tyler H Coale
- Ocean Sciences Department, University of California, Santa Cruz, CA, USA
| | - Valentina Loconte
- Department of Anatomy, School of Medicine, University of California, San Francisco, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Kendra A Turk-Kubo
- Ocean Sciences Department, University of California, Santa Cruz, CA, USA
| | - Bieke Vanslembrouck
- Department of Anatomy, School of Medicine, University of California, San Francisco, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | | - Shunyan Cheung
- Institute of Marine Biology and Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan
| | - Axel Ekman
- Department of Anatomy, School of Medicine, University of California, San Francisco, CA, USA
| | - Jian-Hua Chen
- Department of Anatomy, School of Medicine, University of California, San Francisco, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Kyoko Hagino
- Marine Core Research Institute, Kochi University, Nankoku, Kochi, Japan
| | - Yoshihito Takano
- Marine Core Research Institute, Kochi University, Nankoku, Kochi, Japan
| | - Tomohiro Nishimura
- Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Hatsukaichi, Hiroshima, Japan
- Laboratory of Aquatic Environmental Science, Faculty of Agriculture and Marine Science, Kochi University, Nankoku, Kochi, Japan
| | - Masao Adachi
- Laboratory of Aquatic Environmental Science, Faculty of Agriculture and Marine Science, Kochi University, Nankoku, Kochi, Japan
| | - Mark Le Gros
- Department of Anatomy, School of Medicine, University of California, San Francisco, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Carolyn Larabell
- Department of Anatomy, School of Medicine, University of California, San Francisco, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jonathan P Zehr
- Ocean Sciences Department, University of California, Santa Cruz, CA, USA
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8
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Thompson AW, Nyerges G, Lamberson KM, Sutherland KR. Ubiquitous filter feeders shape open ocean microbial community structure and function. PNAS NEXUS 2024; 3:pgae091. [PMID: 38505693 PMCID: PMC10949910 DOI: 10.1093/pnasnexus/pgae091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 02/13/2024] [Indexed: 03/21/2024]
Abstract
The mechanism of mortality plays a large role in how microorganisms in the open ocean contribute to global energy and nutrient cycling. Salps are ubiquitous pelagic tunicates that are a well-known mortality source for large phototrophic microorganisms in coastal and high-latitude systems, but their impact on the immense populations of smaller prokaryotes in the tropical and subtropical open ocean gyres is not well quantified. We used robustly quantitative techniques to measure salp clearance and enrichment of specific microbial functional groups in the North Pacific Subtropical Gyre, one of the largest ecosystems on Earth. We discovered that salps are a previously unknown predator of the globally abundant nitrogen fixer Crocosphaera; thus, salps restrain new nitrogen delivery to the marine ecosystem. We show that the ocean's two numerically dominant cells, Prochlorococcus and SAR11, are not consumed by salps, which offers a new explanation for the dominance of small cells in open ocean systems. We also identified a double bonus for Prochlorococcus, wherein it not only escapes salp predation but the salps also remove one of its major mixotrophic predators, the prymnesiophyte Chrysochromulina. When we modeled the interaction between salp mesh and particles, we found that cell size alone could not account for these prey selection patterns. Instead, the results suggest that alternative mechanisms, such as surface property, shape, nutritional quality, or even prey behavior, determine which microbial cells are consumed by salps. Together, these results identify salps as a major factor in shaping the structure, function, and ecology of open ocean microbial communities.
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Affiliation(s)
- Anne W Thompson
- Department of Biology, Portland State University, Portland, OR 97201, USA
| | - Györgyi Nyerges
- Department of Biology, Pacific University, Forest Grove, OR 97116, USA
| | - Kylee M Lamberson
- Department of Chemistry, Portland State University, Portland, OR 97201, USA
| | - Kelly R Sutherland
- Oregon Institute of Marine Biology, University of Oregon, Eugene, OR 97403, USA
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9
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Colussi A, Bokhari SNH, Mijovilovich A, Koník P, Küpper H. Acclimation to medium-level non-lethal iron limitation: Adjustment of electron flow around the PSII and metalloprotein expression in Trichodesmium erythraeum IMS101. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149015. [PMID: 37742749 DOI: 10.1016/j.bbabio.2023.149015] [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: 03/17/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/26/2023]
Abstract
The aim of this study was to investigate how acclimation to medium-level, long-term, non-lethal iron limitation changes the electron flux around the Photosystem II of the oceanic diazotroph Trichodesmium erythraeum IMS101. Fe availability of about 5× and 100× lower than a replete level, i.e. conditions common in the natural environment of this cyanobacterium, were applied in chemostats. The response of the cells was studied not only in terms of growth, but also mechanistically, measuring the chlorophyll fluorescence of dark-adapted filaments via imaging fluorescence kinetic microscopy (FKM) with 0.3 ms time resolution. Combining these measurements with those of metal binding to proteins via online coupling of metal-free HPLC (size exclusion chromatography SEC) to sector-field ICP-MS allowed to track the fate of the photosystems, together with other metalloproteins. General increase of fluorescence has been observed, with the consequent decrease in the quantum yields φ of the PSII, while the efficiency ψ of the electron flux between PSII and the PSI remained surprisingly unchanged. This indicates the ability of Trichodesmium to cope with a situation that makes assembling the many iron clusters in Photosystem I a particular challenge, as shown by decreasing ratios of Fe to Mg in these proteins. The negative effect of Fe limitation on PSII may also be due to its fast turnover. A broader view was obtained from metalloproteomics via HPLC-ICP-MS, revealing a differential protein expression pattern under iron limitation with a drastic down-regulation especially of iron-containing proteins and some increase in low MW metal-binding complexes.
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Affiliation(s)
- Antonio Colussi
- Czech Academy of Sciences, Biology Centre, Institute of Plant Molecular Biology, Laboratory of Plant Biophysics and Biochemistry, České Budějovice, Czech Republic; University of South Bohemia, Faculty of Sciences, Department of Experimental Plant Biology, České Budějovice, Czech Republic
| | - Syed Nadeem Hussain Bokhari
- Czech Academy of Sciences, Biology Centre, Institute of Plant Molecular Biology, Laboratory of Plant Biophysics and Biochemistry, České Budějovice, Czech Republic
| | - Ana Mijovilovich
- Czech Academy of Sciences, Biology Centre, Institute of Plant Molecular Biology, Laboratory of Plant Biophysics and Biochemistry, České Budějovice, Czech Republic
| | - Peter Koník
- University of South Bohemia, Faculty of Sciences, Department of Chemistry, České Budějovice, Czech Republic
| | - Hendrik Küpper
- Czech Academy of Sciences, Biology Centre, Institute of Plant Molecular Biology, Laboratory of Plant Biophysics and Biochemistry, České Budějovice, Czech Republic; University of South Bohemia, Faculty of Sciences, Department of Experimental Plant Biology, České Budějovice, Czech Republic.
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10
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Golovko G, Khanipov K, Reyes V, Pinchuk I, Fofanov Y. Identification of multivariable Boolean patterns in microbiome and microbial gene composition data. Biosystems 2023; 233:105007. [PMID: 37619924 DOI: 10.1016/j.biosystems.2023.105007] [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: 03/29/2023] [Revised: 08/05/2023] [Accepted: 08/21/2023] [Indexed: 08/26/2023]
Abstract
Virtually every biological system is governed by complex relations among its components. Identifying such relations requires a rigorous or heuristics-based search for patterns among variables/features of a system. Various algorithms have been developed to identify two-dimensional (involving two variables) patterns employing correlation, covariation, mutual information, etc. It seems obvious, however, that comprehensive descriptions of complex biological systems need also to include more complicated multivariable relations, which can only be described using patterns that simultaneously embrace 3, 4, and more variables. The goal of this manuscript is to (a) introduce a novel type of associations (multivariable Boolean patterns) that can be manifested between features of complex systems but cannot be identified (described) by traditional pair-vise metrics; (b) propose patterns classification method, and (c) provide a novel definition of the pattern's strength (pattern's score) able to accommodate heterogeneous multi-omics data. To demonstrate the presence of such patterns, we performed a search for all possible 2-, 3-, and 4-dimensional patterns in historical data from the Human Microbiome Project (15 body sites) and collection of H. pylori genomes associated with gastric ulcers, gastritis, and duodenal ulcers. In all datasets under consideration, we were able to identify hundreds of statistically significant multivariable patterns. These results suggest that such patterns can be common in microbial genomics/microbiomics systems.
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Affiliation(s)
- George Golovko
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA
| | - Kamil Khanipov
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA
| | - Victor Reyes
- Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA
| | - Irina Pinchuk
- Department of Medicine, Penn State Health Milton Hershey Medical Center, Hershey, PA, USA
| | - Yuriy Fofanov
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA; Glass Bottom Analytics Inc, League City, TX, USA.
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11
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Esteves SM, Jadoul A, Iacono F, Schloesser M, Bosman B, Carnol M, Druet T, Cardol P, Hanikenne M. Natural variation of nutrient homeostasis among laboratory and field strains of Chlamydomonas reinhardtii. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:5198-5217. [PMID: 37235689 DOI: 10.1093/jxb/erad194] [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: 12/02/2022] [Accepted: 05/24/2023] [Indexed: 05/28/2023]
Abstract
Natural variation among individuals and populations exists in all species, playing key roles in response to environmental stress and adaptation. Micro- and macronutrients have a wide range of functions in photosynthetic organisms, and mineral nutrition thus plays a sizable role in biomass production. To maintain nutrient concentrations inside the cell within physiological limits and prevent the detrimental effects of deficiency or excess, complex homeostatic networks have evolved in photosynthetic cells. The microalga Chlamydomonas reinhardtii (Chlamydomonas) is a unicellular eukaryotic model for studying such mechanisms. In this work, 24 Chlamydomonas strains, comprising field isolates and laboratory strains, were examined for intraspecific differences in nutrient homeostasis. Growth and mineral content were quantified in mixotrophy, as full nutrition control, and compared with autotrophy and nine deficiency conditions for macronutrients (-Ca, -Mg, -N, -P, and -S) and micronutrients (-Cu, -Fe, -Mn, and -Zn). Growth differences among strains were relatively limited. However, similar growth was accompanied by highly divergent mineral accumulation among strains. The expression of nutrient status marker genes and photosynthesis were scored in pairs of contrasting field strains, revealing distinct transcriptional regulation and nutrient requirements. Leveraging this natural variation should enable a better understanding of nutrient homeostasis in Chlamydomonas.
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Affiliation(s)
- Sara M Esteves
- InBioS-PhytoSystems, Translational Plant Biology, University of Liège, Belgium
| | - Alice Jadoul
- InBioS-PhytoSystems, Translational Plant Biology, University of Liège, Belgium
| | - Fabrizio Iacono
- InBioS-PhytoSystems, Genetics and Physiology of Microalgae, University of Liège, Belgium
| | - Marie Schloesser
- InBioS-PhytoSystems, Translational Plant Biology, University of Liège, Belgium
| | - Bernard Bosman
- InBioS-PhytoSystems, Laboratory of Plant and Microbial Ecology, University of Liège, Belgium
| | - Monique Carnol
- InBioS-PhytoSystems, Laboratory of Plant and Microbial Ecology, University of Liège, Belgium
| | - Tom Druet
- Unit of Animal Genomics (GIGA), University of Liège, Belgium
| | - Pierre Cardol
- InBioS-PhytoSystems, Genetics and Physiology of Microalgae, University of Liège, Belgium
| | - Marc Hanikenne
- InBioS-PhytoSystems, Translational Plant Biology, University of Liège, Belgium
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12
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Payne D, Spietz RL, Newell DL, Dijkstra P, Boyd ES. Influence of sulfide on diazotrophic growth of the methanogen Methanococcus maripaludis and its implications for the origin of nitrogenase. Commun Biol 2023; 6:799. [PMID: 37524775 PMCID: PMC10390477 DOI: 10.1038/s42003-023-05163-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 07/21/2023] [Indexed: 08/02/2023] Open
Abstract
Methanogens inhabit euxinic (sulfide-rich) or ferruginous (iron-rich) environments that promote the precipitation of transition metals as metal sulfides, such as pyrite, reducing metal or sulfur availability. Such environments have been common throughout Earth's history raising the question as to how anaerobes obtain(ed) these elements for the synthesis of enzyme cofactors. Here, we show a methanogen can synthesize molybdenum nitrogenase metallocofactors from pyrite as the source of iron and sulfur, enabling nitrogen fixation. Pyrite-grown, nitrogen-fixing cells grow faster and require 25-fold less molybdenum than cells grown under euxinic conditions. Growth yields are 3 to 8 times higher in cultures grown under ferruginous relative to euxinic conditions. Physiological, transcriptomic, and geochemical data indicate these observations are due to sulfide-promoted metal limitation, in particular molybdenum. These findings suggest that molybdenum nitrogenase may have originated in a ferruginous environment that titrated sulfide to form pyrite, facilitating the availability of sufficient iron, sulfur, and molybdenum for cofactor biosynthesis.
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Affiliation(s)
- Devon Payne
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, 59717, USA
| | - Rachel L Spietz
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, 59717, USA
| | - Dennis L Newell
- Department of Geosciences, Utah State University, Logan, UT, 84322, USA
| | - Paul Dijkstra
- Center for Ecosystem Science and Society and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Eric S Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, 59717, USA.
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13
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Luo W, Luo YW. Diurnally dynamic iron allocation promotes N 2 fixation in marine dominant diazotroph Trichodesmium. Comput Struct Biotechnol J 2023; 21:3503-3512. [PMID: 37484493 PMCID: PMC10362294 DOI: 10.1016/j.csbj.2023.07.006] [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: 02/14/2023] [Revised: 06/15/2023] [Accepted: 07/04/2023] [Indexed: 07/25/2023] Open
Abstract
Trichodesmium is the dominant photoautotrophic dinitrogen (N2) fixer (diazotroph) in the ocean. Iron is an important factor limiting growth of marine diazotrophs including Trichodesmium mainly because of high iron content of its N2-fixing enzyme, nitrogenase. However, it still lacks a quantitative understanding of how dynamic iron allocation among physiological processes acts to regulate growth and N2 fixation in Trichodesmium. Here, we constructed a model of Trichodesmium trichome in which intracellular iron could be dynamically re-allocated in photosystems and nitrogenase during the daytime. The results demonstrate that the dynamic iron allocation enhances modeled N2 fixation and growth rates of Trichodesmium, especially in iron-limited conditions, albeit having a marginal impact under high iron concentrations. Although the reuse of iron during a day is an apparent cause that dynamic iron allocation can benefit Trichodesmium under iron limitation, our model reveals two important mechanisms. First, the release of iron from photosystems downregulates the intracellular oxygen (O2) production and reduces the demand of respiratory protection, a process that Trichodesmium wastefully respires carbohydrates to create a lower O2 window for N2 fixation. Hence, more carbohydrates can be used in growth. Second, lower allocation of iron to nitrogenase during early daytime, a period when photosynthesis is active and intracellular O2 is high, reduces the amount of iron that is trapped in the inactivated nitrogenase induced by O2. This mechanism further increases the iron use efficiency in Trichodesmium. Overall, our study provides mechanistic and quantitative insight into the diurnal iron allocation that can alleviate iron limitation to Trichodesmium.
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14
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Abstract
Living systems are built from a small subset of the atomic elements, including the bulk macronutrients (C,H,N,O,P,S) and ions (Mg,K,Na,Ca) together with a small but variable set of trace elements (micronutrients). Here, we provide a global survey of how chemical elements contribute to life. We define five classes of elements: those that are (i) essential for all life, (ii) essential for many organisms in all three domains of life, (iii) essential or beneficial for many organisms in at least one domain, (iv) beneficial to at least some species, and (v) of no known beneficial use. The ability of cells to sustain life when individual elements are absent or limiting relies on complex physiological and evolutionary mechanisms (elemental economy). This survey of elemental use across the tree of life is encapsulated in a web-based, interactive periodic table that summarizes the roles chemical elements in biology and highlights corresponding mechanisms of elemental economy.
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Affiliation(s)
- Kaleigh A Remick
- Department of Microbiology, Cornell University, New York, NY, United States
| | - John D Helmann
- Department of Microbiology, Cornell University, New York, NY, United States.
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15
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He ZW, Zou ZS, Ren YX, Tang CC, Zhou AJ, Liu W, Wang L, Li Z, Wang A. Roles of zero-valent iron in anaerobic digestion: Mechanisms, advances and perspectives. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 852:158420. [PMID: 36049687 DOI: 10.1016/j.scitotenv.2022.158420] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 08/26/2022] [Accepted: 08/26/2022] [Indexed: 06/15/2023]
Abstract
With the rapid growth of population and urbanization, more and more bio-wastes have been produced. Considering organics contained in bio-wastes, to recover resource from bio-wastes is of great significance, which can not only achieve the resource recycle, but also protect the environment. Anaerobic digestion (AD) has been proved as one of the most promising strategies to recover bio-energy from bio-wastes, as well as to realize the reduction of bio-wastes. However, the conventional interspecies electron transfer is sensitive to environmental shocks, such as high ammonia, organic pollutants, metal ions, etc., which lead to instability or failure of AD. The recent findings have proved that the introduction of zero-valent iron (ZVI) in AD system can significantly enhance methane production from bio-wastes. This review systematically highlighted the recent advances on the roles of ZVI in AD, including underlying mechanisms of ZVI on AD, performance enhancement of AD contributed by ZVI, and impact factors of AD regulated by ZVI. Furthermore, current limitations and outlooks have been analyzed and concluded. The roles of ZVI on underlying mechanisms in AD include regulating reaction conditions, electron transfer mode and function of microbial communities. The addition of ZVI in AD can not only enhance bio-energy recovery and toxic contaminants removal from bio-wastes, but also have the potential to buffer adverse effect caused by inhibitors. Moreover, the electron transfer modes induced by ZVI include both interspecies hydrogen transfer and direct interspecies electron transfer pathways. How to comprehensively evaluate the effects of ZVI on AD and further improve the roles of ZVI in AD is urgently needed for practical application of ZVI in AD. This review aims to provide some references for the introduction of ZVI in AD for enhancing bio-energy recovery from bio-wastes.
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Affiliation(s)
- Zhang-Wei He
- Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Zheng-Shuo Zou
- Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yong-Xiang Ren
- Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Cong-Cong Tang
- Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Ai-Juan Zhou
- College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Wenzong Liu
- State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China
| | - Ling Wang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266000, China
| | - Zhihua Li
- Shaanxi Key Laboratory of Environmental Engineering, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Aijie Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China
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16
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Wrightson L, Yang N, Mahaffey C, Hutchins DA, Tagliabue A. Integrating the impact of global change on the niche and physiology of marine nitrogen-fixing cyanobacteria. GLOBAL CHANGE BIOLOGY 2022; 28:7078-7093. [PMID: 36054414 PMCID: PMC9826025 DOI: 10.1111/gcb.16399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 08/05/2022] [Accepted: 08/10/2022] [Indexed: 06/15/2023]
Abstract
Marine nitrogen fixation is a major source of new nitrogen to the ocean, which interacts with climate driven changes to physical nutrient supply to regulate the response of ocean primary production in the oligotrophic tropical ocean. Warming and changes in nutrient supply may alter the ecological niche of nitrogen-fixing organisms, or 'diazotrophs', however, impacts of warming on diazotroph physiology may also be important. Lab-based studies reveal that warming increases the nitrogen fixation-specific elemental use efficiency (EUE) of two prevalent marine diazotrophs, Crocosphaera and Trichodesmium, thus reducing their requirements for the limiting nutrients iron and phosphorus. Here, we coupled a new diazotroph model based upon observed diazotroph energetics of growth and resource limitation to a state-of-the-art global model of phytoplankton physiology and ocean biogeochemistry. Our model is able to address the integrated response of nitrogen fixation by Trichodesmium and Crocosphaera to warming under the IPCC high emission RCP8.5 scenario for the first time. Our results project a global decline in nitrogen fixation over the coming century. However, the regional response of nitrogen fixation to climate change is modulated by the diazotroph-specific thermal performance curves and EUE, particularly in the Pacific Ocean, which shapes global trends. Spatially, the response of both diazotrophs is similar with expansion towards higher latitudes and reduced rates of nitrogen fixation in the lower latitudes. Overall, 95%-97% of the nitrogen fixation climate signal can be attributed to the combined effect of temperature on the niche and physiology of marine diazotrophs, with decreases being associated with a reduced niche and increases resulting due to a combination of expanding niche and temperature driven changes to EUE. Climate change impacts on both the niche and physiology of marine diazotrophs interact to shape patterns of marine nitrogen fixation, which will have important implications for ocean productivity in the future.
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Affiliation(s)
- Lewis Wrightson
- Department of Earth, Ocean and Ecological SciencesUniversity of LiverpoolLiverpoolUK
| | - Nina Yang
- Department of Biological SciencesUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Claire Mahaffey
- Department of Earth, Ocean and Ecological SciencesUniversity of LiverpoolLiverpoolUK
| | - David A. Hutchins
- Department of Biological SciencesUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
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17
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Yang N, Lin YA, Merkel CA, DeMers MA, Qu PP, Webb EA, Fu FX, Hutchins DA. Molecular mechanisms underlying iron and phosphorus co-limitation responses in the nitrogen-fixing cyanobacterium Crocosphaera. THE ISME JOURNAL 2022; 16:2702-2711. [PMID: 36008474 PMCID: PMC9666452 DOI: 10.1038/s41396-022-01307-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 08/04/2022] [Accepted: 08/09/2022] [Indexed: 12/15/2022]
Abstract
In the nitrogen-limited subtropical gyres, diazotrophic cyanobacteria, including Crocosphaera, provide an essential ecosystem service by converting dinitrogen (N2) gas into ammonia to support primary production in these oligotrophic regimes. Natural gradients of phosphorus (P) and iron (Fe) availability in the low-latitude oceans constrain the biogeography and activity of diazotrophs with important implications for marine biogeochemical cycling. Much remains unknown regarding Crocosphaera's physiological and molecular responses to multiple nutrient limitations. We cultured C. watsonii under Fe, P, and Fe/P (co)-limiting scenarios to link cellular physiology with diel gene expression and observed unique physiological and transcriptional profiles for each treatment. Counterintuitively, reduced growth and N2 fixation resource use efficiencies (RUEs) for Fe or P under P limitation were alleviated under Fe/P co-limitation. Differential gene expression analyses show that Fe/P co-limited cells employ the same responses as single-nutrient limited cells that reduce cellular nutrient requirements and increase responsiveness to environmental change including smaller cell size, protein turnover (Fe-limited), and upregulation of environmental sense-and-respond systems (P-limited). Combined, these mechanisms enhance growth and RUEs in Fe/P co-limited cells. These findings are important to our understanding of nutrient controls on N2 fixation and the implications for primary productivity and microbial dynamics in a changing ocean.
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Affiliation(s)
- Nina Yang
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Yu-An Lin
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Carlin A Merkel
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Michelle A DeMers
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Ping-Ping Qu
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Eric A Webb
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Fei-Xue Fu
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - David A Hutchins
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.
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18
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Inomura K, Deutsch C, Jahn O, Dutkiewicz S, Follows MJ. Global patterns in marine organic matter stoichiometry driven by phytoplankton ecophysiology. NATURE GEOSCIENCE 2022; 15:1034-1040. [PMID: 36530964 PMCID: PMC9749492 DOI: 10.1038/s41561-022-01066-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/29/2022] [Indexed: 05/28/2023]
Abstract
The proportion of major elements in marine organic matter links cellular processes to global nutrient, oxygen and carbon cycles. Differences in the C:N:P ratios of organic matter have been observed between ocean biomes, but these patterns have yet to be quantified from the underlying small-scale physiological and ecological processes. Here we use an ecosystem model that includes adaptive resource allocation within and between ecologically distinct plankton size classes to attribute the causes of global patterns in the C:N:P ratios. We find that patterns of N:C variation are largely driven by common physiological adjustment strategies across all phytoplankton, while patterns of N:P are driven by ecological selection for taxonomic groups with different phosphorus storage capacities. Although N:C varies widely due to cellular adjustment to light and nutrients, its latitudinal gradient is modest because of depth-dependent trade-offs between nutrient and light availability. Strong latitudinal variation in N:P reflects an ecological balance favouring small plankton with lower P storage capacity in the subtropics, and larger eukaryotes with a higher cellular P storage capacity in nutrient-rich high latitudes. A weaker N:P difference between southern and northern hemispheres, and between the Atlantic and Pacific oceans, reflects differences in phosphate available for cellular storage. Despite simulating only two phytoplankton size classes, the emergent global variability of elemental ratios resembles that of all measured species, suggesting that the range of growth conditions and ecological selection sustain the observed diversity of stoichiometry among phytoplankton.
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Affiliation(s)
- Keisuke Inomura
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI USA
- School of Oceanography, University of Washington, Seattle, WA USA
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Curtis Deutsch
- School of Oceanography, University of Washington, Seattle, WA USA
- Department of Geosciences and High Meadows Environmental Institute, Princeton University, Princeton, NJ USA
| | - Oliver Jahn
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Stephanie Dutkiewicz
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Michael J. Follows
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA USA
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19
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Lerch BA, Smith DA, Koffel T, Bagby SC, Abbott KC. How public can public goods be? Environmental context shapes the evolutionary ecology of partially private goods. PLoS Comput Biol 2022; 18:e1010666. [PMID: 36318525 PMCID: PMC9651594 DOI: 10.1371/journal.pcbi.1010666] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 11/11/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
The production of costly public goods (as distinct from metabolic byproducts) has largely been understood through the realization that spatial structure can minimize losses to non-producing "cheaters" by allowing for the positive assortment of producers. In well-mixed systems, where positive assortment is not possible, the stable production of public goods has been proposed to depend on lineages that become indispensable as the sole producers of those goods while their neighbors lose production capacity through genome streamlining (the Black Queen Hypothesis). Here, we develop consumer-resource models motivated by nitrogen-fixing, siderophore-producing bacteria that consider the role of colimitation in shaping eco-evolutionary dynamics. Our models demonstrate that in well-mixed environments, single "public goods" can only be ecologically and evolutionarily stable if they are partially privatized (i.e., if producers reserve a portion of the product pool for private use). Colimitation introduces the possibility of subsidy: strains producing a fully public good can exclude non-producing strains so long as the producing strain derives sufficient benefit from the production of a second partially private good. We derive a lower bound for the degree of privatization necessary for production to be advantageous, which depends on external resource concentrations. Highly privatized, low-investment goods, in environments where the good is limiting, are especially likely to be stably produced. Coexistence emerges more rarely in our mechanistic model of the external environment than in past phenomenological approaches. Broadly, we show that the viability of production depends critically on the environmental context (i.e., external resource concentrations), with production of shared resources favored in environments where a partially-privatized resource is scarce.
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Affiliation(s)
- Brian A. Lerch
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Derek A. Smith
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Thomas Koffel
- W. K. Kellogg Biological Station, Michigan State University, Hickory Corners, Michigan, United States of America
| | - Sarah C. Bagby
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Karen C. Abbott
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
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20
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Masuda T, Inomura K, Kodama T, Shiozaki T, Kitajima S, Armin G, Matsui T, Suzuki K, Takeda S, Sato M, Prášil O, Furuya K. Crocosphaera as a Major Consumer of Fixed Nitrogen. Microbiol Spectr 2022; 10:e0217721. [PMID: 35770981 PMCID: PMC9431459 DOI: 10.1128/spectrum.02177-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 06/05/2022] [Indexed: 11/23/2022] Open
Abstract
Crocosphaera watsonii (hereafter referred to as Crocosphaera) is a key nitrogen (N) fixer in the ocean, but its ability to consume combined-N sources is still unclear. Using in situ microcosm incubations with an ecological model, we show that Crocosphaera has high competitive capability both under low and moderately high combined-N concentrations. In field incubations, Crocosphaera accounted for the highest consumption of ammonium and nitrate, followed by picoeukaryotes. The model analysis shows that cells have a high ammonium uptake rate (~7 mol N [mol N]-1 d-1 at the maximum), which allows them to compete against picoeukaryotes and nondiazotrophic cyanobacteria when combined N is sufficiently available. Even when combined N is depleted, their capability of nitrogen fixation allows higher growth rates compared to potential competitors. These results suggest the high fitness of Crocosphaera in combined-N limiting, oligotrophic oceans heightening its potential significance in its ecosystem and in biogeochemical cycling. IMPORTANCE Crocosphaera watsonii is as a key nitrogen (N) supplier in marine ecosystems, and it has been estimated to contribute up to half of oceanic N2 fixation. Conversely, a recent study reported that Crocosphaera can assimilate combined N and proposed that unicellular diazotrophs can be competitors with non-N2 fixing phytoplankton for combined N. Despite its importance in nitrogen cycling, the methods by which Crocosphaera compete are not currently fully understood. Here, we present a new role of Crocosphaera as a combined-N consumer: a competitor against nondiazotrophic phytoplankton for combined N. In this study, we combined in situ microcosm experiments and an ecosystem model to quantitatively evaluate the combined-N consumption by Crocosphaera and other non-N2 fixing phytoplankton. Our results suggest the high fitness of Crocosphaera in combined-N limiting, oligotrophic oceans and, thus, heightens its potential significance in its ecosystem and in biogeochemical cycling.
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Affiliation(s)
- Takako Masuda
- Department of Aquatic Bioscience, The University of Tokyo, Tokyo, Japan
- Institute of Microbiology, The Czech Academy of Sciences, Třeboň, Czech Republic
| | - Keisuke Inomura
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA
| | - Taketoshi Kodama
- Department of Aquatic Bioscience, The University of Tokyo, Tokyo, Japan
| | - Takuhei Shiozaki
- Department of Aquatic Bioscience, The University of Tokyo, Tokyo, Japan
| | - Satoshi Kitajima
- Department of Aquatic Bioscience, The University of Tokyo, Tokyo, Japan
| | - Gabrielle Armin
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA
| | - Takato Matsui
- Graduate School of Environmental Science/Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan
| | - Koji Suzuki
- Graduate School of Environmental Science/Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan
| | - Shigenobu Takeda
- Department of Aquatic Bioscience, The University of Tokyo, Tokyo, Japan
| | - Mitsuhide Sato
- Department of Aquatic Bioscience, The University of Tokyo, Tokyo, Japan
| | - Ondřej Prášil
- Institute of Microbiology, The Czech Academy of Sciences, Třeboň, Czech Republic
| | - Ken Furuya
- Department of Aquatic Bioscience, The University of Tokyo, Tokyo, Japan
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21
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Fourquez M, Strzepek RF, Ellwood MJ, Hassler C, Cabanes D, Eggins S, Pearce I, Deppeler S, Trull TW, Boyd PW, Bressac M. Phytoplankton Responses to Bacterially Regenerated Iron in a Southern Ocean Eddy. Microorganisms 2022; 10:microorganisms10081655. [PMID: 36014073 PMCID: PMC9413495 DOI: 10.3390/microorganisms10081655] [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: 07/06/2022] [Revised: 08/07/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022] Open
Abstract
In the Subantarctic sector of the Southern Ocean, vertical entrainment of iron (Fe) triggers the seasonal productivity cycle but diminishing physical supply during the spring to summer transition forces microbial assemblages to rapidly acclimate. Here, we tested how phytoplankton and bacteria within an isolated eddy respond to different dissolved Fe (DFe)/ligand inputs. We used three treatments: one that mimicked the entrainment of new DFe (Fe-NEW), another in which DFe was supplied from bacterial regeneration of particles (Fe-REG), and a control with no addition of DFe (Fe-NO). After 6 days, 3.5 (Fe-NO, Fe-NEW) to 5-fold (Fe-REG) increases in Chlorophyll a were observed. These responses of the phytoplankton community were best explained by the differences between the treatments in the amount of DFe recycled during the incubation (Fe-REG, 15% recycled c.f. 40% Fe-NEW, 60% Fe-NO). This additional recycling was more likely mediated by bacteria. By day 6, bacterial production was comparable between Fe-NO and Fe-NEW but was approximately two-fold higher in Fe-REG. A preferential response of phytoplankton (haptophyte-dominated) relative to high nucleic acid (HNA) bacteria was also found in the Fe-REG treatment while the relative proportion of diatoms increased faster in the Fe-NEW and Fe-NO treatments. Comparisons between light and dark incubations further confirmed the competition between picophytoplankton and HNA for DFe. Overall, our results demonstrate great versatility by microorganisms to use different Fe sources that results in highly efficient Fe recycling within surface waters. This study also encourages future research to further investigate the interactions between functional groups of microbes (e.g. HNA and cyanobacteria) to better constraint modeling in Fe and carbon biogeochemical cycles.
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Affiliation(s)
- Marion Fourquez
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobart 7004, Australia
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UMR 110, 13288 Marseille, France
- Correspondence:
| | - Robert F. Strzepek
- Australian Antarctic Program Partnership (AAPP), Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
| | - Michael J. Ellwood
- Research School of Earth Sciences, Australian National University, Canberra 2601, Australia
| | - Christel Hassler
- Marine and Lake Biogeochemistry, Department F.-A. Forel, University of Geneva, 1205 Geneva, Switzerland
- Institute of Earth Sciences, University of Lausanne, 1015 Lausanne, Switzerland
| | - Damien Cabanes
- Marine and Lake Biogeochemistry, Department F.-A. Forel, University of Geneva, 1205 Geneva, Switzerland
| | - Sam Eggins
- Research School of Earth Sciences, Australian National University, Canberra 2601, Australia
| | - Imojen Pearce
- Australian Antarctic Division (AAD), Kingston 7050, Australia
| | - Stacy Deppeler
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- National Institute of Water and Atmospheric Research, Wellington 6021, New Zealand
| | - Thomas W. Trull
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobart 7004, Australia
- Climate Science Centre, Oceans and Atmosphere, Commonwealth Scientific and Industrial Research Organisation, Hobart 7004, Australia
| | - Philip W. Boyd
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobart 7004, Australia
| | - Matthieu Bressac
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- Laboratoire d’Océanographie de Villefranche, Sorbonne Université, CNRS, 06230 Villefranche-sur-Mer, France
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22
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Strzepek RF, Nunn BL, Bach LT, Berges JA, Young EB, Boyd PW. The ongoing need for rates: can physiology and omics come together to co-design the measurements needed to understand complex ocean biogeochemistry? JOURNAL OF PLANKTON RESEARCH 2022; 44:485-495. [PMID: 35898813 PMCID: PMC9310281 DOI: 10.1093/plankt/fbac026] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 05/05/2022] [Indexed: 05/16/2023]
Abstract
The necessity to understand the influence of global ocean change on biota has exposed wide-ranging gaps in our knowledge of the fundamental principles that underpin marine life. Concurrently, physiological research has stagnated, in part driven by the advent and rapid evolution of molecular biological techniques, such that they now influence all lines of enquiry in biological oceanography. This dominance has led to an implicit assumption that physiology is outmoded, and advocacy that ecological and biogeochemical models can be directly informed by omics. However, the main modeling currencies are biological rates and biogeochemical fluxes. Here, we ask: how do we translate the wealth of information on physiological potential from omics-based studies to quantifiable physiological rates and, ultimately, to biogeochemical fluxes? Based on the trajectory of the state-of-the-art in biomedical sciences, along with case-studies from ocean sciences, we conclude that it is unlikely that omics can provide such rates in the coming decade. Thus, while physiological rates will continue to be central to providing projections of global change biology, we must revisit the metrics we rely upon. We advocate for the co-design of a new generation of rate measurements that better link the benefits of omics and physiology.
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Affiliation(s)
- Robert F Strzepek
- Australian Antarctic Program Partnership (AAPP), Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Hobart, TAS 7004, Australia
| | - Brook L Nunn
- Department of Genome Sciences, University of Washington, Foege Building S113 3720 15th Ave NE, Seattle, WA 98195, USA
| | - Lennart T Bach
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS 7004, Australia
| | - John A Berges
- Department of Biological Sciences and School of Freshwater Sciences, University of Wisconsin-Milwaukee, 3209 N. Maryland Avenue, Milwaukee, WI 53211, USA
| | - Erica B Young
- Department of Biological Sciences and School of Freshwater Sciences, University of Wisconsin-Milwaukee, 3209 N. Maryland Avenue, Milwaukee, WI 53211, USA
| | - Philip W Boyd
- Australian Antarctic Program Partnership (AAPP), Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Hobart, TAS 7004, Australia
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS 7004, Australia
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23
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Lory C, Van Wambeke F, Fourquez M, Barani A, Guieu C, Tilliette C, Marie D, Nunige S, Berman-Frank I, Bonnet S. Assessing the contribution of diazotrophs to microbial Fe uptake using a group specific approach in the Western Tropical South Pacific Ocean. ISME COMMUNICATIONS 2022; 2:41. [PMID: 37938297 PMCID: PMC9723570 DOI: 10.1038/s43705-022-00122-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 03/26/2022] [Accepted: 04/07/2022] [Indexed: 04/27/2023]
Abstract
Diazotrophs are often limited by iron (Fe) availability in the oligotrophic ocean. The Western Tropical South Pacific (WTSP) ocean has been suggested as an intense N2 fixation area due to Fe fertilizations through shallow hydrothermal activity. Yet, the Fe demand of diazotrophs in their natural habitat, where they cohabit with other microbial organisms also requiring Fe, remains unknown. Here we develop and apply a method consisting of coupling 55Fe uptake experiments with cell-sorting by flow cytometry, and provide group-specific rates of in situ Fe uptake by the microbial community in the WTSP, in addition to bulk and size fractionation rates. We reveal that the diazotrophs Crocosphaera watsonii and Trichodesmium contribute substantially to the bulk in situ Fe uptake (~33% on average over the studied area), despite being numerically less abundant compared to the rest of the planktonic community. Trichodesmium had the highest cell-specific Fe uptake rates, followed by C. watsonii, picoeukaryotes, Prochlorococcus, Synechococcus and finally heterotrophic bacteria. Calculated Fe:C quotas were higher (by 2 to 52-fold) for both studied diazotrophs compared to those of the non-diazotrophic plankton, reflecting their high intrinsic Fe demand. This translates into a diazotroph biogeographical distribution that appears to be influenced by ambient dissolved Fe concentrations in the WTSP. Despite having low cell-specific uptake rates, Prochlorococcus and heterotrophic bacteria were largely the main contributors to the bulk Fe uptake (~23% and ~12%, respectively). Overall, this group-specific approach increases our ability to examine the ecophysiological role of functional groups, including those of less abundant and/or less active microbes.
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Affiliation(s)
- C Lory
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France.
| | - F Van Wambeke
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - M Fourquez
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - A Barani
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - C Guieu
- Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, LOV, F-06230, Villefranche-sur-Mer, France
| | - C Tilliette
- Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, LOV, F-06230, Villefranche-sur-Mer, France
| | - D Marie
- Sorbonne Université, CNRS, Station Biologique de Roscoff, Roscoff, France
| | - S Nunige
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - I Berman-Frank
- Department of Marine Biology, The Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - S Bonnet
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France.
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24
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Benavides M, Caffin M, Duhamel S, Foster RA, Grosso O, Guieu C, Van Wambeke F, Bonnet S. Anomalously high abundance of Crocosphaera in the South Pacific Gyre. FEMS Microbiol Lett 2022; 369:6565802. [PMID: 35396843 DOI: 10.1093/femsle/fnac039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/22/2022] [Accepted: 04/06/2022] [Indexed: 11/12/2022] Open
Abstract
The unicellular diazotrophic cyanobacterium Crocosphaera contributes significantly to fixed nitrogen inputs in the oligotrophic ocean. In the western tropical South Pacific Ocean (WTSP), these diazotrophs abound thanks to the phosphorus-rich waters provided by the South Equatorial Current, and iron provided aeolian and subsurface volcanic activity. East of the WTSP, the South Pacific Gyre (SPG) harbors the most oligotrophic and transparent waters of the world's oceans, where only heterotrophic diazotrophs have been reported before. Here in the SPG we detected unexpected accumulation of Crocosphaera at 50 m with peak abundances of 5.26×105nifH gene copies L-1. The abundance of Crocosphaera at 50 m was in the same order of magnitude as those detected westwards in the WTSP and represented 100% of volumetric N2 fixation rates. This accumulation at 50 m was likely due to a deeper penetration of UV light in the clear waters of the SPG being detrimental for Crocosphaera growth and N2 fixation activity. Nutrient and trace metal addition experiments did not induce any significant changes in N2 fixation or Crocosphaera abundance, indicating that this population was not limited by the resources tested and could develop in high numbers despite the oligotrophic conditions. Our findings indicate that the distribution of Crocosphaera can extend into subtropical gyres and further understanding of their controlling factors is needed.
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Affiliation(s)
- Mar Benavides
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Mathieu Caffin
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Solange Duhamel
- Lamont Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA
| | - Rachel Ann Foster
- Stockholm University, Department of Ecology, Environment and Plant Sciences, Stockholm, Sweden
| | - Olivier Grosso
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Cécile Guieu
- Sorbonne Universités, UPMC Univ Paris 06, INSU-CNRS, Laboratoire d'Océanographie de Villefranche, 181 Chemin du Lazaret, 06230 Villefranche-sur-mer, France.,Center for Prototype Climate Modeling, New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - France Van Wambeke
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Sophie Bonnet
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
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25
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Cerdan-Garcia E, Baylay A, Polyviou D, Woodward EMS, Wrightson L, Mahaffey C, Lohan MC, Moore CM, Bibby TS, Robidart JC. Transcriptional responses of Trichodesmium to natural inverse gradients of Fe and P availability. THE ISME JOURNAL 2022; 16:1055-1064. [PMID: 34819612 PMCID: PMC8941076 DOI: 10.1038/s41396-021-01151-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 10/28/2021] [Accepted: 11/01/2021] [Indexed: 12/28/2022]
Abstract
The filamentous diazotrophic cyanobacterium Trichodesmium is responsible for a significant fraction of marine di-nitrogen (N2) fixation. Growth and distribution of Trichodesmium and other diazotrophs in the vast oligotrophic subtropical gyres is influenced by iron (Fe) and phosphorus (P) availability, while reciprocally influencing the biogeochemistry of these nutrients. Here we use observations across natural inverse gradients in Fe and P in the North Atlantic subtropical gyre (NASG) to demonstrate how Trichodesmium acclimates in situ to resource availability. Transcriptomic analysis identified progressive upregulation of known iron-stress biomarker genes with decreasing Fe availability, and progressive upregulation of genes involved in the acquisition of diverse P sources with decreasing P availability, while genes involved in N2 fixation were upregulated at the intersection under moderate Fe and P availability. Enhanced N2 fixation within the Fe and P co-stressed transition region was also associated with a distinct, consistent metabolic profile, including the expression of alternative photosynthetic pathways that potentially facilitate ATP generation required for N2 fixation with reduced net oxygen production. The observed response of Trichodesmium to availability of both Fe and P supports suggestions that these biogeochemically significant organisms employ unique molecular, and thus physiological responses as adaptations to specifically exploit the Fe and P co-limited niche they construct.
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Affiliation(s)
- E Cerdan-Garcia
- Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK.
| | - A Baylay
- Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
| | - D Polyviou
- National Oceanography Centre, Southampton, SO14 3ZH, UK
| | | | - L Wrightson
- Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - C Mahaffey
- Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - M C Lohan
- Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
| | - C M Moore
- Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
| | - T S Bibby
- Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
| | - J C Robidart
- National Oceanography Centre, Southampton, SO14 3ZH, UK.
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26
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Masuda T, Inomura K, Mareš J, Prášil O. Crocosphaera watsonii. Trends Microbiol 2022; 30:805-806. [PMID: 35331632 DOI: 10.1016/j.tim.2022.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 11/27/2022]
Affiliation(s)
- Takako Masuda
- Institute of Microbiology, The Czech Academy of Sciences, Opatovický mlýn, 379 01 Třeboň, Czech Republic.
| | - Keisuke Inomura
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA
| | - Jan Mareš
- Institute of Microbiology, The Czech Academy of Sciences, Opatovický mlýn, 379 01 Třeboň, Czech Republic; Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 702/7, 370 05 České Budějovice, Czech Republic
| | - Ondřej Prášil
- Institute of Microbiology, The Czech Academy of Sciences, Opatovický mlýn, 379 01 Třeboň, Czech Republic
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27
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Held NA, Waterbury JB, Webb EA, Kellogg RM, McIlvin MR, Jakuba M, Valois FW, Moran DM, Sutherland KM, Saito MA. Dynamic diel proteome and daytime nitrogenase activity supports buoyancy in the cyanobacterium Trichodesmium. Nat Microbiol 2022; 7:300-311. [PMID: 35013592 PMCID: PMC10288448 DOI: 10.1038/s41564-021-01028-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 11/17/2021] [Indexed: 12/13/2022]
Abstract
Cyanobacteria of the genus Trichodesmium provide about 80 Tg of fixed nitrogen to the surface ocean per year and contribute to marine biogeochemistry, including the sequestration of carbon dioxide. Trichodesmium fixes nitrogen in the daylight, despite the incompatibility of the nitrogenase enzyme with oxygen produced during photosynthesis. While the mechanisms protecting nitrogenase remain unclear, all proposed strategies require considerable resource investment. Here we identify a crucial benefit of daytime nitrogen fixation in Trichodesmium spp. that may counteract these costs. We analysed diel proteomes of cultured and field populations of Trichodesmium in comparison with the marine diazotroph Crocosphaera watsonii WH8501, which fixes nitrogen at night. Trichodesmium's proteome is extraordinarily dynamic and demonstrates simultaneous photosynthesis and nitrogen fixation, resulting in balanced particulate organic carbon and particulate organic nitrogen production. Unlike Crocosphaera, which produces large quantities of glycogen as an energy store for nitrogenase, proteomic evidence is consistent with the idea that Trichodesmium reduces the need to produce glycogen by supplying energy directly to nitrogenase via soluble ferredoxin charged by the photosynthesis protein PsaC. This minimizes ballast associated with glycogen, reducing cell density and decreasing sinking velocity, thus supporting Trichodesmium's niche as a buoyant, high-light-adapted colony forming cyanobacterium. To occupy its niche of simultaneous nitrogen fixation and photosynthesis, Trichodesmium appears to be a conspicuous consumer of iron, and has therefore developed unique iron-acquisition strategies, including the use of iron-rich dust. Particle capture by buoyant Trichodesmium colonies may increase the residence time and degradation of mineral iron in the euphotic zone. These findings describe how cellular biochemistry defines and reinforces the ecological and biogeochemical function of these keystone marine diazotrophs.
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Affiliation(s)
- Noelle A Held
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
- Department of Earth, Atmospheric and Planetary Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Environmental Systems Science, ETH, Zurich, Switzerland
| | - John B Waterbury
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Eric A Webb
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Riss M Kellogg
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
- Department of Earth, Atmospheric and Planetary Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Matthew R McIlvin
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Michael Jakuba
- Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Frederica W Valois
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Dawn M Moran
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Kevin M Sutherland
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
- Department of Earth, Atmospheric and Planetary Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - Mak A Saito
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
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28
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Complex marine microbial communities partition metabolism of scarce resources over the diel cycle. Nat Ecol Evol 2022; 6:218-229. [DOI: 10.1038/s41559-021-01606-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/01/2021] [Indexed: 12/20/2022]
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29
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Walworth NG, Saito MA, Lee MD, McIlvin MR, Moran DM, Kellogg RM, Fu FX, Hutchins DA, Webb EA. Why Environmental Biomarkers Work: Transcriptome-Proteome Correlations and Modeling of Multistressor Experiments in the Marine Bacterium Trichodesmium. J Proteome Res 2021; 21:77-89. [PMID: 34855411 DOI: 10.1021/acs.jproteome.1c00517] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ocean microbial communities are important contributors to the global biogeochemical reactions that sustain life on Earth. The factors controlling these communities are being increasingly explored using metatranscriptomic and metaproteomic environmental biomarkers. Using published proteomes and transcriptomes from the abundant colony-forming cyanobacterium Trichodesmium (strain IMS101) grown under varying Fe and/or P limitation in low and high CO2, we observed robust correlations of stress-induced proteins and RNAs (i.e., involved in transport and homeostasis) that yield useful information on the nutrient status under low and/or high CO2. Conversely, transcriptional and translational correlations of many other central metabolism pathways exhibit broad discordance. A cellular RNA and protein production/degradation model demonstrates how biomolecules with small initial inventories, such as environmentally responsive proteins, achieve large increases in fold-change units as opposed to those with a higher basal expression and inventory such as metabolic systems. Microbial cells, due to their immersion in the environment, tend to show large adaptive responses in both RNA and protein that result in transcript-protein correlations. These observations and model results demonstrate multi-omic coherence for environmental biomarkers and provide the underlying mechanism for those observations, supporting the promise for global application in detecting responses to environmental stimuli in a changing ocean.
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Affiliation(s)
- Nathan G Walworth
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, United States
| | - Mak A Saito
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Michael D Lee
- Blue Marble Space Institute of Science, Seattle, Washington 98104, United States.,Exobiology Branch, NASA Ames Research Center, Moffett Field, California 94035, United States
| | - Matthew R McIlvin
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Dawn M Moran
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Riss M Kellogg
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Fei-Xue Fu
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, United States
| | - David A Hutchins
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, United States
| | - Eric A Webb
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, United States
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30
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Groussman RD, Coesel SN, Durham BP, Armbrust EV. Diel-Regulated Transcriptional Cascades of Microbial Eukaryotes in the North Pacific Subtropical Gyre. Front Microbiol 2021; 12:682651. [PMID: 34659137 PMCID: PMC8511712 DOI: 10.3389/fmicb.2021.682651] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 08/11/2021] [Indexed: 11/13/2022] Open
Abstract
Open-ocean surface waters host a diverse community of single-celled eukaryotic plankton (protists) consisting of phototrophs, heterotrophs, and mixotrophs. The productivity and biomass of these organisms oscillate over diel cycles, and yet the underlying transcriptional processes are known for few members of the community. Here, we examined a 4-day diel time series of transcriptional abundance profiles for the protist community (0.2-100 μm in cell size) in the North Pacific Subtropical Gyre near Station ALOHA. De novo assembly of poly-A+ selected metatranscriptomes yielded over 30 million contigs with taxonomic and functional annotations assigned to 54 and 25% of translated contigs, respectively. The completeness of the resulting environmental eukaryotic taxonomic bins was assessed, and 48 genera were further evaluated for diel patterns in transcript abundances. These environmental transcriptome bins maintained reproducible temporal partitioning of total gene family abundances, with haptophyte and ochrophyte genera generally showing the greatest diel partitioning of their transcriptomes. The haptophyte Phaeocystis demonstrated the highest proportion of transcript diel periodicity, while most other protists had intermediate levels of periodicity regardless of their trophic status. Dinoflagellates, except for the parasitoid genus Amoebophrya, exhibit the fewest diel oscillations of transcript abundances. Diel-regulated gene families were enriched in key metabolic pathways; photosynthesis, carbon fixation, and fatty acid biosynthesis gene families had peak times concentrated around dawn, while gene families involved in protein turnover (proteasome and protein processing) are most active during the high intensity daylight hours. TCA cycle, oxidative phosphorylation and fatty acid degradation predominantly peaked near dusk. We identified temporal pathway enrichments unique to certain taxa, including assimilatory sulfate reduction at dawn in dictyophytes and signaling pathways at early evening in haptophytes, pointing to possible taxon-specific channels of carbon and nutrients through the microbial community. These results illustrate the synchrony of transcriptional regulation to the diel cycle and how the protist community of the North Pacific Subtropical Gyre structures their transcriptomes to guide the daily flux of matter and energy through the gyre ecosystem.
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Affiliation(s)
- Ryan D. Groussman
- School of Oceanography, University of Washington, Seattle, WA, United States
| | - Sacha N. Coesel
- School of Oceanography, University of Washington, Seattle, WA, United States
| | - Bryndan P. Durham
- School of Oceanography, University of Washington, Seattle, WA, United States
- Department of Biology, Genetics Institute, University of Florida, Gainesville, FL, United States
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31
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Landolfi A, Prowe AEF, Pahlow M, Somes CJ, Chien CT, Schartau M, Koeve W, Oschlies A. Can Top-Down Controls Expand the Ecological Niche of Marine N 2 Fixers? Front Microbiol 2021; 12:690200. [PMID: 34489886 PMCID: PMC8416505 DOI: 10.3389/fmicb.2021.690200] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 07/05/2021] [Indexed: 01/12/2023] Open
Abstract
The ability of marine diazotrophs to fix dinitrogen gas (N2) is one of the most influential yet enigmatic processes in the ocean. With their activity diazotrophs support biological production by fixing about 100–200 Tg N/year and turning otherwise unavailable dinitrogen into bioavailable nitrogen (N), an essential limiting nutrient. Despite their important role, the factors that control the distribution of diazotrophs and their ability to fix N2 are not fully elucidated. We discuss insights that can be gained from the emerging picture of a wide geographical distribution of marine diazotrophs and provide a critical assessment of environmental (bottom-up) versus trophic (top-down) controls. We expand a simplified theoretical framework to understand how top-down control affects competition for resources that determine ecological niches. Selective mortality, mediated by grazing or viral-lysis, on non-fixing phytoplankton is identified as a critical process that can broaden the ability of diazotrophs to compete for resources in top-down controlled systems and explain an expanded ecological niche for diazotrophs. Our simplified analysis predicts a larger importance of top-down control on competition patterns as resource levels increase. As grazing controls the faster growing phytoplankton, coexistence of the slower growing diazotrophs can be established. However, these predictions require corroboration by experimental and field data, together with the identification of specific traits of organisms and associated trade-offs related to selective top-down control. Elucidation of these factors could greatly improve our predictive capability for patterns and rates of marine N2 fixation. The susceptibility of this key biogeochemical process to future changes may not only be determined by changes in environmental conditions but also via changes in the ecological interactions.
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Affiliation(s)
- Angela Landolfi
- Institute of Marine Sciences, National Research Council, Rome, Italy.,Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - A E Friederike Prowe
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Markus Pahlow
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Christopher J Somes
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Chia-Te Chien
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Markus Schartau
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Wolfgang Koeve
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Andreas Oschlies
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
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Gene Cluster Analysis of Marine Bacteria Seeking for Natural Anticancer Products. Jundishapur J Nat Pharm Prod 2021. [DOI: 10.5812/jjnpp.104665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: In the past decade, metabolites of marine microorganisms have been increasingly used for their various biological activities. An intense effort has been dedicated to assessing the therapeutic efficacy of the marine natural products and metabolites obtained from marine bacteria in cancer therapy. Fast and reliable analytical bacterial genome sequencing provides specialized bioinformatic tools to identify potential gene clusters in bacteria for obtaining secondary metabolites. Objectives: This study aimed to analyze the genome sequences of marine bacteria to recognize bioactive compounds with anti-cancer properties. Methods: Marine bacteria with the genomic sequences registered in the National Center for Biotechnology Information (NCBI) genome database were used in this study. The genome was analyzed for proteins, tRNAs, and rRNAs from GenBank entries by Feature Extract 1.2L Server. The Anti-SMASH webserver was used for the analysis of unique marine bacterial metabolites of the marine bacterial genome, available from the NCBI database. Results: A number of marine bacterial species, including Salinispora arenicola, Salinispora tropica, Crocosphaera watsonii, and Blastopirellula marina encoded metabolites belonging to the polyketide and nonribosomal peptide (NRP) families, showing anti-cancer properties. Among the marine species described, S. tropica and S. arenicola are richer in the genes encoding polyketide and NRP with potential antitumor activities. Conclusions: Marine bacteria are an excellent and exceptional source of anti-cancer compounds. In silico genome analysis of marine bacteria provided an opportunity to evaluate gene clusters for known natural products. Like this chemical engineering approaches for pharmaceutical application are useful in clinical evaluation of cancer treatment.
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Wang K, Mou X. Coordinated Diel Gene Expression of Cyanobacteria and Their Microbiome. Microorganisms 2021; 9:microorganisms9081670. [PMID: 34442749 PMCID: PMC8398468 DOI: 10.3390/microorganisms9081670] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 11/16/2022] Open
Abstract
Diel rhythms have been well recognized in cyanobacterial metabolisms. However, whether this programmed activity of cyanobacteria could elicit coordinated diel gene expressions in microorganisms (microbiome) that co-occur with cyanobacteria and how such responses in turn impact cyanobacterial metabolism are unknown. To address these questions, a microcosm experiment was set up using Lake Erie water to compare the metatranscriptomic variations of Microcystis cells alone, the microbiome alone, and these two together (whole water) over two day-night cycles. A total of 1205 Microcystis genes and 4779 microbiome genes exhibited significant diel expression patterns in the whole-water microcosm. However, when Microcystis and the microbiome were separated, only 515 Microcystis genes showed diel expression patterns. A significant structural change was not observed for the microbiome communities between the whole-water and microbiome microcosms. Correlation analyses further showed that diel expressions of carbon, nitrogen, phosphorous, and micronutrient (iron and vitamin B12) metabolizing genes were significantly coordinated between Microcystis and the microbiome in the whole-water microcosm. Our results suggest that diel fluxes of organic carbon and vitamin B12 (cobalamin) in Microcystis could cause the diel expression of microbiome genes. Meanwhile, the microbiome communities may support the growth of Microcystis by supplying them with recycled nutrients, but compete with Microcystis for iron.
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Held NA, Sutherland KM, Webb EA, McIlvin MR, Cohen NR, Devaux AJ, Hutchins DA, Waterbury JB, Hansel CM, Saito MA. Mechanisms and heterogeneity of in situ mineral processing by the marine nitrogen fixer Trichodesmium revealed by single-colony metaproteomics. ISME COMMUNICATIONS 2021; 1:35. [PMID: 36739337 PMCID: PMC9723768 DOI: 10.1038/s43705-021-00034-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 06/10/2021] [Accepted: 06/18/2021] [Indexed: 02/06/2023]
Abstract
The keystone marine nitrogen fixer Trichodesmium thrives in high-dust environments. While laboratory investigations have observed that Trichodesmium colonies can access the essential nutrient iron from dust particles, less clear are the biochemical strategies underlying particle-colony interactions in nature. Here we demonstrate that Trichodesmium colonies engage with mineral particles in the wild with distinct molecular responses. We encountered particle-laden Trichodesmium colonies at a sampling location in the Southern Caribbean Sea; microscopy and synchrotron-based imaging then demonstrated heterogeneous associations with iron oxide and iron-silicate minerals. Metaproteomic analysis of individual colonies by a new low-biomass approach revealed responses in biogeochemically relevant proteins including photosynthesis proteins and metalloproteins containing iron, nickel, copper, and zinc. The iron-storage protein ferritin was particularly enriched implying accumulation of mineral-derived iron, and multiple iron acquisition pathways including Fe(II), Fe(III), and Fe-siderophore transporters were engaged. While the particles provided key trace metals such as iron and nickel, there was also evidence that Trichodesmium was altering its strategy to confront increased superoxide production and metal exposure. Chemotaxis regulators also responded to mineral presence suggesting involvement in particle entrainment. These molecular responses are fundamental to Trichodesmium's ecological success and global biogeochemical impact, and may contribute to the leaching of particulate trace metals with implications for global iron and carbon cycling.
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Affiliation(s)
- Noelle A Held
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Kevin M Sutherland
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - Eric A Webb
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Matthew R McIlvin
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Natalie R Cohen
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Alexander J Devaux
- Department of Microbiology, Boston University School of Medicine, Boston, MA, USA
| | - David A Hutchins
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - John B Waterbury
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Colleen M Hansel
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Mak A Saito
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
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Muratore D, Weitz JS. Infect while the iron is scarce: nutrient-explicit phage-bacteria games. THEOR ECOL-NETH 2021. [DOI: 10.1007/s12080-021-00508-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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36
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Particulate Metabolites and Transcripts Reflect Diel Oscillations of Microbial Activity in the Surface Ocean. mSystems 2021; 6:6/3/e00896-20. [PMID: 33947808 PMCID: PMC8269247 DOI: 10.1128/msystems.00896-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Light fuels photosynthesis and organic matter production by primary producers in the sunlit ocean. The quantity and quality of the organic matter produced influence community function, yet in situ measurements of metabolites, the products of cellular metabolism, over the diel cycle are lacking. We evaluated community-level biochemical consequences of oscillations of light in the North Pacific Subtropical Gyre by quantifying 79 metabolites in particulate organic matter from 15 m every 4 h over 8 days. Total particulate metabolite concentration peaked at dusk and represented up to 2% of total particulate organic carbon (POC). The concentrations of 55/79 (70%) individual metabolites exhibited significant 24-h periodicity, with daily fold changes from 1.6 to 12.8, often greater than those of POC and flow cytometry-resolvable biomass, which ranged from 1.2 to 2.8. Paired metatranscriptome analysis revealed the taxa involved in production and consumption of a subset of metabolites. Primary metabolites involved in anabolism and redox maintenance had significant 24-h periodicity and diverse organisms exhibited diel periodicity in transcript abundance associated with these metabolites. Compounds with osmotic properties displayed the largest oscillations in concentration, implying rapid turnover and supporting prior evidence of functions beyond cell turgor maintenance. The large daily oscillation of trehalose paired with metatranscriptome and culture data showed that trehalose is produced by the nitrogen-fixing cyanobacterium Crocosphaera, likely to store energy for nighttime metabolism. Together, paired measurements of particulate metabolites and transcripts resolve strategies that microbes use to manage daily energy and redox oscillations and highlight dynamic metabolites with cryptic roles in marine microbial ecosystems.IMPORTANCE Fueled by light, phytoplankton produce the organic matter that supports ocean ecosystems and carbon sequestration. Ocean change impacts microbial metabolism with repercussions for biogeochemical cycling. As the small molecule products of cellular metabolism, metabolites often change rapidly in response to environmental conditions and form the basis of energy and nutrient management and storage within cells. By pairing measurements of metabolites and gene expression in the stratified surface ocean, we reveal strategies of microbial energy management over the day-night cycle and hypothesize that oscillating metabolites are important substrates for dark respiration by phytoplankton. These high-resolution diel measurements of in situ metabolite concentrations form the basis for future work into the specific roles these compounds play in marine microbial communities.
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Qiu GW, Jiang HB, Lis H, Li ZK, Deng B, Shang JL, Sun CY, Keren N, Qiu BS. A unique porin meditates iron-selective transport through cyanobacterial outer membranes. Environ Microbiol 2020; 23:376-390. [PMID: 33196124 DOI: 10.1111/1462-2920.15324] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 11/02/2020] [Accepted: 11/12/2020] [Indexed: 10/23/2022]
Abstract
Cyanobacteria are globally important primary producers and nitrogen fixers with high iron demands. Low ambient dissolved iron concentrations in many aquatic environments mean that these organisms must maintain sufficient and selective transport of iron into the cell. However, the nature of iron transport pathways through the cyanobacterial outer membrane remains obscure. Here we present multiple lines of experimental evidence that collectively support the existence of a novel class of substrate-selective iron porin, Slr1908, in the outer membrane of the cyanobacterium Synechocystis sp. PCC 6803. Elemental composition analysis and short-term iron uptake assays with mutants in Slr1908 reveal that this protein is primarily involved in inorganic iron uptake and contributes less to the accumulation of other metals. Homologues of Slr1908 are widely distributed in both freshwater and marine cyanobacteria, most notably in unicellular marine diazotrophs. Complementary experiments with a homologue of Slr1908 in Synechococcus sp. PCC 7002 restored the phenotype of Synechocystis knockdown mutants, showing that this siderophore producing species also possesses a porin with a similar function in Fe transport. The involvement of a substrate-selective porins in iron uptake may allow cyanobacteria to tightly control iron flux into the cell, particularly in environments where iron concentrations fluctuate.
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Affiliation(s)
- Guo-Wei Qiu
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
| | - Hai-Bo Jiang
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
| | - Hagar Lis
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, Israel
| | - Zheng-Ke Li
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
| | - Bin Deng
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
| | - Jin-Long Shang
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
| | - Chuan-Yu Sun
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
| | - Nir Keren
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, Israel
| | - Bao-Sheng Qiu
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, China
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Inomura K, Deutsch C, Masuda T, Prášil O, Follows MJ. Quantitative models of nitrogen-fixing organisms. Comput Struct Biotechnol J 2020; 18:3905-3924. [PMID: 33335688 PMCID: PMC7733014 DOI: 10.1016/j.csbj.2020.11.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 11/11/2020] [Accepted: 11/13/2020] [Indexed: 10/26/2022] Open
Abstract
Nitrogen-fixing organisms are of importance to the environment, providing bioavailable nitrogen to the biosphere. Quantitative models have been used to complement the laboratory experiments and in situ measurements, where such evaluations are difficult or costly. Here, we review the current state of the quantitative modeling of nitrogen-fixing organisms and ways to enhance the bridge between theoretical and empirical studies.
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Affiliation(s)
- Keisuke Inomura
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Curtis Deutsch
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Takako Masuda
- Institute of Microbiology, The Czech Academy of Sciences, Opatovický mlýn, Třeboň, Czech Republic
| | - Ondřej Prášil
- Institute of Microbiology, The Czech Academy of Sciences, Opatovický mlýn, Třeboň, Czech Republic
| | - Michael J. Follows
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
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Combined pigment and metatranscriptomic analysis reveals highly synchronized diel patterns of phenotypic light response across domains in the open oligotrophic ocean. ISME JOURNAL 2020; 15:520-533. [PMID: 33033374 DOI: 10.1038/s41396-020-00793-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 09/18/2020] [Accepted: 09/23/2020] [Indexed: 01/01/2023]
Abstract
Sunlight is the most important environmental control on diel fluctuations in phytoplankton activity, and understanding diel microbial processes is essential to the study of oceanic biogeochemical cycles. Yet, little is known about the in situ temporal dynamics of phytoplankton metabolic activities and their coordination across different populations. We investigated diel orchestration of phytoplankton activity in photosynthesis, photoacclimation, and photoprotection by analyzing pigment and quinone distributions in combination with metatranscriptomes in surface waters of the North Pacific Subtropical Gyre (NPSG). We found diel cycles in pigment abundances resulting from the balance of their synthesis and consumption. These dynamics suggest that night represents a metabolic recovery phase, refilling cellular pigment stores, while photosystems are remodeled towards photoprotection during daytime. Transcript levels of genes involved in photosynthesis and pigment metabolism had synchronized diel expression patterns among all taxa, reflecting the driving force light imparts upon photosynthetic organisms in the ocean, while other environmental factors drive niche differentiation. For instance, observed decoupling of diel oscillations in transcripts and related pigments indicates that pigment abundances are modulated by environmental factors extending beyond gene expression/regulation reinforcing the need to combine metatranscriptomics with proteomics and metabolomics to fully understand the timing of these critical processes in situ.
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Golovko G, Kamil K, Albayrak L, Nia AM, Duarte RSA, Chumakov S, Fofanov Y. Identification of multidimensional Boolean patterns in microbial communities. MICROBIOME 2020; 8:131. [PMID: 32917276 PMCID: PMC7488411 DOI: 10.1186/s40168-020-00853-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 05/04/2020] [Indexed: 05/09/2023]
Abstract
BACKGROUND Identification of complex multidimensional interaction patterns within microbial communities is the key to understand, modulate, and design beneficial microbiomes. Every community has members that fulfill an essential function affecting multiple other community members through secondary metabolism. Since microbial community members are often simultaneously involved in multiple relations, not all interaction patterns for such microorganisms are expected to exhibit a visually uninterrupted pattern. As a result, such relations cannot be detected using traditional correlation, mutual information, principal coordinate analysis, or covariation-based network inference approaches. RESULTS We present a novel pattern-specific method to quantify the strength and estimate the statistical significance of two-dimensional co-presence, co-exclusion, and one-way relation patterns between abundance profiles of two organisms as well as extend this approach to allow search and visualize three-, four-, and higher dimensional patterns. The proposed approach has been tested using 2380 microbiome samples from the Human Microbiome Project resulting in body site-specific networks of statistically significant 2D patterns as well as revealed the presence of 3D patterns in the Human Microbiome Project data. CONCLUSIONS The presented study suggested that search for Boolean patterns in the microbial abundance data needs to be pattern specific. The reported presence of multidimensional patterns (which cannot be reduced to a combination of two-dimensional patterns) suggests that multidimensional (multi-organism) relations may play important roles in the organization of microbial communities, and their detection (and appropriate visualization) may lead to a deeper understanding of the organization and dynamics of microbial communities. Video Abstract.
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Affiliation(s)
- George Golovko
- Department of Pharmacology and Toxicology, University of Texas Medical Branch–Galveston, Galveston, TX 77555-0144 USA
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch–Galveston, Galveston, TX 77555-0144 USA
| | - Khanipov Kamil
- Department of Pharmacology and Toxicology, University of Texas Medical Branch–Galveston, Galveston, TX 77555-0144 USA
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch–Galveston, Galveston, TX 77555-0144 USA
| | - Levent Albayrak
- Department of Pharmacology and Toxicology, University of Texas Medical Branch–Galveston, Galveston, TX 77555-0144 USA
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch–Galveston, Galveston, TX 77555-0144 USA
| | - Anna M. Nia
- Department of Molecular Biophysics, University of Texas Medical Branch–Galveston, Galveston, TX 77555-0144 USA
| | | | - Sergei Chumakov
- Department of Physics, University of Guadalajara, Revolucion, 1500 Guadalajara, Jalisco Mexico
| | - Yuriy Fofanov
- Department of Pharmacology and Toxicology, University of Texas Medical Branch–Galveston, Galveston, TX 77555-0144 USA
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch–Galveston, Galveston, TX 77555-0144 USA
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Minimal cobalt metabolism in the marine cyanobacterium Prochlorococcus. Proc Natl Acad Sci U S A 2020; 117:15740-15747. [PMID: 32576688 DOI: 10.1073/pnas.2001393117] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Despite very low concentrations of cobalt in marine waters, cyanobacteria in the genus Prochlorococcus retain the genetic machinery for the synthesis and use of cobalt-bearing cofactors (cobalamins) in their genomes. We explore cobalt metabolism in a Prochlorococcus isolate from the equatorial Pacific Ocean (strain MIT9215) through a series of growth experiments under iron- and cobalt-limiting conditions. Metal uptake rates, quantitative proteomic measurements of cobalamin-dependent enzymes, and theoretical calculations all indicate that Prochlorococcus MIT9215 can sustain growth with less than 50 cobalt atoms per cell, ∼100-fold lower than minimum iron requirements for these cells (∼5,100 atoms per cell). Quantitative descriptions of Prochlorococcus cobalt limitation are used to interpret the cobalt distribution in the equatorial Pacific Ocean, where surface concentrations are among the lowest measured globally but Prochlorococcus biomass is high. A low minimum cobalt quota ensures that other nutrients, notably iron, will be exhausted before cobalt can be fully depleted, helping to explain the persistence of cobalt-dependent metabolism in marine cyanobacteria.
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Zhang X, Ward BB, Sigman DM. Global Nitrogen Cycle: Critical Enzymes, Organisms, and Processes for Nitrogen Budgets and Dynamics. Chem Rev 2020; 120:5308-5351. [DOI: 10.1021/acs.chemrev.9b00613] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xinning Zhang
- Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States
- Princeton Environmental Institute, Princeton University, Princeton, New Jersey 08544, United States
| | - Bess B. Ward
- Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States
- Princeton Environmental Institute, Princeton University, Princeton, New Jersey 08544, United States
| | - Daniel M. Sigman
- Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States
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Abstract
Nitrogen fixation, the reduction of atmospheric dinitrogen gas (N2) to ammonia, is critical for biological productivity but is difficult to study in the vast expanse of the global ocean. Decades of field studies and the infusion of molecular biological, genomic, isotopic, and geochemical modeling approaches have led to new paradigms and questions. The discovery of previously unknown N2-fixing (diazotrophic) microorganisms and unusual physiological adaptations, combined with diagnostic distributions of nutrients and their isotopes as well as measured and modeled biogeographic patterns, have revolutionized our understanding of marine N2 fixation and its role in the global nitrogen cycle. Anthropogenic upper-ocean warming, increased dissolved carbon dioxide, and acidification will affect the distribution and relative importance of specific subgroups of N2 fixers in the sea; these changes have implications for foodwebs and biogeochemical cycles.
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Affiliation(s)
- Jonathan P. Zehr
- Department of Ocean Sciences, University of California, Santa Cruz, CA 95003, USA
| | - Douglas G. Capone
- Marine and Environmental Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
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Jia J, Gao Y, Lu Y, Shi K, Li Z, Wang S. Trace metal effects on gross primary productivity and its associative environmental risk assessment in a subtropical lake, China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 259:113848. [PMID: 31901797 DOI: 10.1016/j.envpol.2019.113848] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/26/2019] [Accepted: 12/16/2019] [Indexed: 06/10/2023]
Abstract
The transport of trace metals in river-lake systems can potentially increase or decrease primary productivity in some basins and subsequently affect the carbon cycle of watersheds. In this study, we investigated a variety of trace metal concentrations and transport flux in the Poyang Lake basin during four seasons. Results show that the Gan River transports 78% of selenium (Se) and 42% of lead (Pb) into Poyang Lake each year, resulting in heavy metal pollution dominated by Pb and Se in 30%-75% of its water. Although toxic heavy metals, such as Pb, chromium (Cr), and copper (Cu), inhibit phytoplankton growth and decrease its gross primary productivity (GPP), excessive Se could effectually promote productivity. However, the negative effect of Pb on GPP is more significant than the positive effect of Se on GPP; hence, their interaction effectuates a decrease in total primary productivity. Additionally, under high nutrients level, the synergistic effect of heavy metals and nutrients will reduce GPP. Agricultural fertilizer is likely the source of both Pb, Cu, Se and N. Gan River contributes 35%-80% of the heavy metal inputs to Poyang Lake. It is therefore necessary to improve the ecological environment of phytoplankton and promote productivity in the Poyang Lake basin by reducing the application of agricultural chemical fertilizers to control pollution. Our results indicate that the role of certain, less studied trace elements (e.g., Pb, Cr, Cu, and Se) in regulating primary productivity of watershed ecosystems is more important than previously thought. This study also discusses potential impacting mechanisms associated with these metals on phytoplankton, whose biological functions need to be verified in future experiments.
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Affiliation(s)
- Junjie Jia
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Yang Gao
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, PR China; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China.
| | - Yao Lu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Kun Shi
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China
| | - Zhaoxi Li
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Shuoyue Wang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
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Louropoulou E, Gledhill M, Achterberg EP, Browning TJ, Honey DJ, Schmitz RA, Tagliabue A. Heme b distributions through the Atlantic Ocean: evidence for "anemic" phytoplankton populations. Sci Rep 2020; 10:4551. [PMID: 32165723 PMCID: PMC7067765 DOI: 10.1038/s41598-020-61425-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 02/24/2020] [Indexed: 11/09/2022] Open
Abstract
Heme b is an iron-containing cofactor in hemoproteins that participates in the fundamental processes of photosynthesis and respiration in phytoplankton. Heme b concentrations typically decline in waters with low iron concentrations but due to lack of field data, the distribution of heme b in particulate material in the ocean is poorly constrained. Here we report particulate heme b distributions across the Atlantic Ocean (59.9°N to 34.6°S). Heme b concentrations in surface waters ranged from 0.10 to 33.7 pmol L-1 (median = 1.47 pmol L-1, n = 974) and were highest in regions with a high biomass. The ratio of heme b to particulate organic carbon (POC) exhibited a mean value of 0.44 μmol heme b mol-1 POC. We identified the ratio of 0.10 µmol heme b mol-1 POC as the cut-off between heme b replete and heme b deficient (anemic) phytoplankton. By this definition, we observed anemic phytoplankton populations in the Subtropical South Atlantic and Irminger Basin. Comparison of observed and modelled heme b suggested that heme b could account for between 0.17-9.1% of biogenic iron. Our large scale observations of heme b relative to organic matter provide further evidence of the impact of changes in iron supply on phytoplankton iron status across the Atlantic Ocean.
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Affiliation(s)
- Evangelia Louropoulou
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany. .,Institute for General Microbiology, Christian-Albrechts-Universität, Kiel, Germany.
| | - Martha Gledhill
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | | | | | - David J Honey
- School of Ocean and Earth Science, University of Southampton, Southampton, UK
| | - Ruth A Schmitz
- Institute for General Microbiology, Christian-Albrechts-Universität, Kiel, Germany
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Inomura K, Omta AW, Talmy D, Bragg J, Deutsch C, Follows MJ. A Mechanistic Model of Macromolecular Allocation, Elemental Stoichiometry, and Growth Rate in Phytoplankton. Front Microbiol 2020; 11:86. [PMID: 32256456 PMCID: PMC7093025 DOI: 10.3389/fmicb.2020.00086] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 01/15/2020] [Indexed: 01/09/2023] Open
Abstract
We present a model of the growth rate and elemental stoichiometry of phytoplankton as a function of resource allocation between and within broad macromolecular pools under a variety of resource supply conditions. The model is based on four, empirically-supported, cornerstone assumptions: that there is a saturating relationship between light and photosynthesis, a linear relationship between RNA/protein and growth rate, a linear relationship between biosynthetic proteins and growth rate, and a constant macromolecular composition of the light-harvesting machinery. We combine these assumptions with statements of conservation of carbon, nitrogen, phosphorus, and energy. The model can be solved algebraically for steady state conditions and constrained with data on elemental stoichiometry from published laboratory chemostat studies. It interprets the relationships between macromolecular and elemental stoichiometry and also provides quantitative predictions of the maximum growth rate at given light intensity and nutrient supply rates. The model is compatible with data sets from several laboratory studies characterizing both prokaryotic and eukaryotic phytoplankton from marine and freshwater environments. It is conceptually simple, yet mechanistic and quantitative. Here, the model is constrained only by elemental stoichiometry, but makes predictions about allocation to measurable macromolecular pools, which could be tested in the laboratory.
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Affiliation(s)
- Keisuke Inomura
- School of Oceanography, University of Washington, Seattle, WA, United States
| | - Anne Willem Omta
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - David Talmy
- Department of Microbiology, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Jason Bragg
- National Herbarium of New South Wales, The Royal Botanic Gardens and Domain Trust, Sydney, NSW, Australia
| | - Curtis Deutsch
- School of Oceanography, University of Washington, Seattle, WA, United States
| | - Michael J. Follows
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
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Quantifying Oxygen Management and Temperature and Light Dependencies of Nitrogen Fixation by Crocosphaera watsonii. mSphere 2019; 4:4/6/e00531-19. [PMID: 31826967 PMCID: PMC6908418 DOI: 10.1128/msphere.00531-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Crocosphaera is a major dinitrogen (N2)-fixing microorganism, providing bioavailable nitrogen (N) to marine ecosystems. The N2-fixing enzyme nitrogenase is deactivated by oxygen (O2), which is abundant in marine environments. Using a cellular scale model of Crocosphaera sp. and laboratory data, we quantify the role of three O2 management strategies by Crocosphaera sp.: size adjustment, reduced O2 diffusivity, and respiratory protection. Our model predicts that Crocosphaera cells increase their size under high O2 Using transmission electron microscopy, we show that starch granules and thylakoid membranes are located near the cytoplasmic membranes, forming a barrier for O2 The model indicates a critical role for respiration in protecting the rate of N2 fixation. Moreover, the rise in respiration rates and the decline in ambient O2 with temperature strengthen this mechanism in warmer water, providing a physiological rationale for the observed niche of Crocosphaera at temperatures exceeding 20°C. Our new measurements of the sensitivity to light intensity show that the rate of N2 fixation reaches saturation at a lower light intensity (∼100 μmol m-2 s-1) than photosynthesis and that both are similarly inhibited by light intensities of >500 μmol m-2 s-1 This suggests an explanation for the maximum population of Crocosphaera occurring slightly below the ocean surface.IMPORTANCE Crocosphaera is one of the major N2-fixing microorganisms in the open ocean. On a global scale, the process of N2 fixation is important in balancing the N budget, but the factors governing the rate of N2 fixation remain poorly resolved. Here, we combine a mechanistic model and both previous and present laboratory studies of Crocosphaera to quantify how chemical factors such as C, N, Fe, and O2 and physical factors such as temperature and light affect N2 fixation. Our study shows that Crocosphaera combines multiple mechanisms to reduce intracellular O2 to protect the O2-sensitive N2-fixing enzyme. Our model, however, indicates that these protections are insufficient at low temperature due to reduced respiration and the rate of N2 fixation becomes severely limited. This provides a physiological explanation for why the geographic distribution of Crocosphaera is confined to the warm low-latitude ocean.
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Active nitrogen fixation by Crocosphaera expands their niche despite the presence of ammonium - A case study. Sci Rep 2019; 9:15064. [PMID: 31636357 PMCID: PMC6803696 DOI: 10.1038/s41598-019-51378-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 09/30/2019] [Indexed: 11/09/2022] Open
Abstract
Unicellular nitrogen fixer Crocosphaera contributes substantially to nitrogen fixation in oligotrophic subtropical gyres. They fix nitrogen even when significant amounts of ammonium are available. This has been puzzling since fixing nitrogen is energetically inefficient compared with using available ammonium. Here we show that by fixing nitrogen, Crocosphaera can increase their population and expand their niche despite the presence of ammonium. We have developed a simple but mechanistic model of Crocosphaera based on their growth in steady state culture. The model shows that the growth of Crocosphaera can become nitrogen limited despite their capability to fix nitrogen. When they fix nitrogen, the population increases by up to 78% relative to the case without nitrogen fixation. When we simulate a simple ecological situation where Crocosphaera exists with non-nitrogen-fixing phytoplankton, the relative abundance of Crocosphaera increases with nitrogen fixation, while the population of non-nitrogen-fixing phytoplankton decreases since a larger fraction of fixed nitrogen is consumed by Crocosphaera. Our study quantitatively supports the benefit of nitrogen fixation despite the high electron/energy costs, even when an energetically efficient alternative is available. It demonstrates a competitive aspect of Crocosphaera, permitting them to be regionally significant nitrogen fixers.
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Burén S, Rubio LM. State of the art in eukaryotic nitrogenase engineering. FEMS Microbiol Lett 2019; 365:4733273. [PMID: 29240940 PMCID: PMC5812491 DOI: 10.1093/femsle/fnx274] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 12/11/2017] [Indexed: 12/27/2022] Open
Abstract
Improving the ability of plants and plant-associated organisms to fix and assimilate atmospheric nitrogen has inspired plant biotechnologists for decades, not only to alleviate negative effects on nature from increased use and availability of reactive nitrogen, but also because of apparent economic benefits and opportunities. The combination of recent advances in synthetic biology and increased knowledge about the biochemistry and biosynthesis of the nitrogenase enzyme has made the seemingly remote and for long unreachable dream more possible. In this review, we will discuss strategies how this could be accomplished using biotechnology, with a special focus on recent progress on engineering plants to express its own nitrogenase.
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Affiliation(s)
- Stefan Burén
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo UPM, 28223-Pozuelo de Alarcón, Madrid, Spain
| | - Luis M Rubio
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo UPM, 28223-Pozuelo de Alarcón, Madrid, Spain
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Guo M, Zhang X, Li M, Li T, Duan X, Zhang D, Hu L, Huang R. Label-Free Proteomic Analysis of Molecular Effects of 2-Methoxy-1,4-naphthoquinone on Penicillium italicum. Int J Mol Sci 2019; 20:ijms20143459. [PMID: 31337149 PMCID: PMC6678512 DOI: 10.3390/ijms20143459] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/06/2019] [Accepted: 07/10/2019] [Indexed: 12/18/2022] Open
Abstract
Penicillium italicum is the principal pathogen causing blue mold of citrus. Searching for novel antifungal agents is an important aspect of the post-harvest citrus industry because of the lack of higher effective and low toxic antifungal agents. Herein, the effects of 2-methoxy-1,4-naphthoquinone (MNQ) on P. italicum and its mechanism were carried out by a series of methods. MNQ had a significant anti-P. italicum effect with an MIC value of 5.0 µg/mL. The label-free protein profiling under different MNQ conditions identified a total of 3037 proteins in the control group and the treatment group. Among them, there were 129 differentially expressed proteins (DEPs, up-regulated > 2.0-fold or down-regulated < 0.5-fold, p < 0.05), 19 up-regulated proteins, 26 down-regulated proteins, and 67 proteins that were specific for the treatment group and another 17 proteins that were specific for the control group. Of these, 83 proteins were sub-categorized into 23 hierarchically-structured GO classifications. Most of the identified DEPs were involved in molecular function (47%), meanwhile 27% DEPs were involved in the cellular component and 26% DEPs were involved in the biological process. Twenty-eight proteins identified for differential metabolic pathways by KEGG were sub-categorized into 60 classifications. Functional characterization by GO and KEGG enrichment results suggests that the DEPs are mainly related to energy generation (mitochondrial carrier protein, glycoside hydrolase, acyl-CoA dehydrogenase, and ribulose-phosphate 3-epimerase), NADPH supply (enolase, pyruvate carboxylase), oxidative stress (catalase, glutathione synthetase), and pentose phosphate pathway (ribulose-phosphate 3-epimerase and xylulose 5-phosphate). Three of the down-regulated proteins selected randomly the nitro-reductase family protein, mono-oxygenase, and cytochrome P450 were verified using parallel reaction monitoring. These findings illustrated that MNQ may inhibit P. italicum by disrupting the metabolic processes, especially in energy metabolism and stimulus response that are both critical for the growth of the fungus. In conclusion, based on the molecular mechanisms, MNQ can be developed as a potential anti-fungi agent against P. italicum.
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Affiliation(s)
- Meixia Guo
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Xiaoyong Zhang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Meiying Li
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Taotao Li
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Xuewu Duan
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Dandan Zhang
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Lianmei Hu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
| | - Riming Huang
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China.
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