1
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Koedooder C, Zhang F, Wang S, Basu S, Haley ST, Tolic N, Nicora CD, Glavina del Rio T, Dyhrman ST, Gledhill M, Boiteau RM, Rubin-Blum M, Shaked Y. Taxonomic distribution of metabolic functions in bacteria associated with Trichodesmium consortia. mSystems 2023; 8:e0074223. [PMID: 37916816 PMCID: PMC10734445 DOI: 10.1128/msystems.00742-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/21/2023] [Indexed: 11/03/2023] Open
Abstract
IMPORTANCE Colonies of the cyanobacteria Trichodesmium act as a biological hotspot for the usage and recycling of key resources such as C, N, P, and Fe within an otherwise oligotrophic environment. While Trichodesmium colonies are known to interact and support a unique community of algae and particle-associated microbes, our understanding of the taxa that populate these colonies and the gene functions they encode is still limited. Characterizing the taxa and adaptive strategies that influence consortium physiology and its concomitant biogeochemistry is critical in a future ocean predicted to have increasingly resource-depleted regions.
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Affiliation(s)
- Coco Koedooder
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
- Israel Oceanographic and Limnological Research, Haifa, Israel
| | - Futing Zhang
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
| | - Siyuan Wang
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
| | - Subhajit Basu
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
- Microsensor Research Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Sheean T. Haley
- Lamont-Doherty Earth Observatory, Columbia University, New York, USA
| | - Nikola Tolic
- Earth and Biological Sciences, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Carrie D. Nicora
- Earth and Biological Sciences, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Tijana Glavina del Rio
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Sonya T. Dyhrman
- Lamont-Doherty Earth Observatory, Columbia University, New York, USA
- Department of Earth and Environmental Sciences, Columbia University, New York, USA
| | | | - Rene M. Boiteau
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, USA
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
| | | | - Yeala Shaked
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
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2
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Rucker HR, Kaçar B. Enigmatic evolution of microbial nitrogen fixation: insights from Earth's past. Trends Microbiol 2023:S0966-842X(23)00091-4. [PMID: 37061455 DOI: 10.1016/j.tim.2023.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 04/17/2023]
Abstract
The evolution of nitrogen fixation undoubtedly altered nearly all corners of the biosphere, given the essential role of nitrogen in the synthesis of biomass. To date, there is no unified view on what planetary conditions gave rise to nitrogen fixation or how these conditions have sustained it evolutionarily. Intriguingly, the concentrations of metals that nitrogenases require to function have changed throughout Earth's history. In this review, we describe the interconnection of the metal and nitrogen cycles with nitrogenase evolution and the importance of ancient ecology in the formation of the modern nitrogen cycle. We argue that exploration of the nitrogen cycle's deep past will provide insights into humanity's immediate environmental challenges centered on nitrogen availability.
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Affiliation(s)
- Holly R Rucker
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Betül Kaçar
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA.
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3
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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: 7] [Impact Index Per Article: 3.5] [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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4
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Blanckaert ACA, Omanović D, Fine M, Grover R, Ferrier-Pagès C. Desert dust deposition supplies essential bioelements to Red Sea corals. GLOBAL CHANGE BIOLOGY 2022; 28:2341-2359. [PMID: 34981609 DOI: 10.1111/gcb.16074] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 12/14/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Climate change-related increase in seawater temperature has become a leading cause of coral bleaching and mortality. However, corals from the northern Red Sea show high thermal tolerance and no recorded massive bleaching event. This specific region is frequently subjected to intense dust storms, coming from the surrounding arid deserts, which are expected to increase in frequency and intensity in the future. The aerial dust deposition supplies essential bioelements to the water column. Here, we investigated the effect of dust deposition on the physiology of a Red Sea coral, Stylophora pistillata. We measured the modifications in coral and Symbiodiniaceae metallome (cellular metal content), as well as the changes in photosynthesis and oxidative stress status of colonies exposed during few weeks to dust deposition. Our results show that 1 mg L-1 of dust supplied nanomolar amounts of nitrate and other essential bioelements, such as iron, manganese, zinc and copper, rapidly assimilated by the symbionts. At 25°C, metal bioaccumulation enhanced the chlorophyll concentration and photosynthesis of dust-exposed corals compared to control corals. These results suggest that primary production was limited by metal availability in seawater. A 5°C increase in seawater temperature enhanced iron assimilation in both control and dust-enriched corals. Temperature rise increased the photosynthesis of control corals only, dust-exposed ones having already reached maximal photosynthesis rates at 25°C. Finally, we observed a combined effect of temperature and bioelement concentration on the assimilation of molybdenum, cadmium, manganese and copper, which were in higher concentrations in symbionts of dust-exposed corals maintained at 30°C. All together these observations highlight the importance of dust deposition in the supply of essential bioelements, such as iron, to corals and its role in sustaining coral productivity in Red Sea reefs.
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Affiliation(s)
- Alice C A Blanckaert
- Centre Scientifique de Monaco, Coral Ecophysiology Team, Monaco, Monaco
- Sorbonne Université, Collège Doctoral, Paris, France
| | - Dario Omanović
- Center for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia
| | - Maoz Fine
- The Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
- The Interuniversity Institute for Marine Science in Eilat, Eilat, Israel
| | - Renaud Grover
- Centre Scientifique de Monaco, Coral Ecophysiology Team, Monaco, Monaco
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5
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Dynamic diel proteome and daytime nitrogenase activity supports buoyancy in the cyanobacterium Trichodesmium. Nat Microbiol 2022; 7:300-311. [PMID: 35013592 DOI: 10.1038/s41564-021-01028-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [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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6
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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: 1.7] [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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7
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Wu S, Mi T, Zhen Y, Yu K, Wang F, Yu Z. A Rise in ROS and EPS Production: New Insights into the Trichodesmium erythraeum Response to Ocean Acidification. JOURNAL OF PHYCOLOGY 2021; 57:172-182. [PMID: 32975309 DOI: 10.1111/jpy.13075] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 08/20/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
The diazotrophic cyanobacterium Trichodesmium is thought to be a major contributor to the new N in parts of the oligotrophic, subtropical, and tropical oceans. In this study, physiological and biochemical methods and transcriptome sequencing were used to investigate the influences of ocean acidification (OA) on Trichodesmium erythraeum (T. erythraeum). We presented evidence that OA caused by CO2 slowed the growth rate and physiological activity of T. erythraeum. OA led to reduced development of proportion of the vegetative cells into diazocytes which included up-regulated genes of nitrogen fixation. Reactive oxygen species (ROS) accumulation was increased due to the disruption of photosynthetic electron transport and decrease in antioxidant enzyme activities under acidified conditions. This study showed that OA increased the amounts of (exopolysaccharides) EPS in T. erythraeum, and the key genes of ribose-5-phosphate (R5P) and glycosyltransferases (Tery_3818) were up-regulated. These results provide new insight into how ROS and EPS of T. erythraeum increase in an acidified future ocean to cope with OA-imposed stress.
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Affiliation(s)
- Shijie Wu
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
| | - Tiezhu Mi
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
| | - Yu Zhen
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
| | - Kaiqiang Yu
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
| | - Fuwen Wang
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China
| | - Zhigang Yu
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education/Institute for Advanced Ocean Study, Ocean University of China, Qingdao, 266100, China
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8
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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: 3.0] [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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9
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Sutak R, Camadro JM, Lesuisse E. Iron Uptake Mechanisms in Marine Phytoplankton. Front Microbiol 2020; 11:566691. [PMID: 33250865 PMCID: PMC7676907 DOI: 10.3389/fmicb.2020.566691] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/19/2020] [Indexed: 12/20/2022] Open
Abstract
Oceanic phytoplankton species have highly efficient mechanisms of iron acquisition, as they can take up iron from environments in which it is present at subnanomolar concentrations. In eukaryotes, three main models were proposed for iron transport into the cells by first studying the kinetics of iron uptake in different algal species and then, more recently, by using modern biological techniques on the model diatom Phaeodactylum tricornutum. In the first model, the rate of uptake is dependent on the concentration of unchelated Fe species, and is thus limited thermodynamically. Iron is transported by endocytosis after carbonate-dependent binding of Fe(III)' (inorganic soluble ferric species) to phytotransferrin at the cell surface. In this strategy the cells are able to take up iron from very low iron concentration. In an alternative model, kinetically limited for iron acquisition, the extracellular reduction of all iron species (including Fe') is a prerequisite for iron acquisition. This strategy allows the cells to take up iron from a great variety of ferric species. In a third model, hydroxamate siderophores can be transported by endocytosis (dependent on ISIP1) after binding to the FBP1 protein, and iron is released from the siderophores by FRE2-dependent reduction. In prokaryotes, one mechanism of iron uptake is based on the use of siderophores excreted by the cells. Iron-loaded siderophores are transported across the cell outer membrane via a TonB-dependent transporter (TBDT), and are then transported into the cells by an ABC transporter. Open ocean cyanobacteria do not excrete siderophores but can probably use siderophores produced by other organisms. In an alternative model, inorganic ferric species are transported through the outer membrane by TBDT or by porins, and are taken up by the ABC transporter system FutABC. Alternatively, ferric iron of the periplasmic space can be reduced by the alternative respiratory terminal oxidase (ARTO) and the ferrous ions can be transported by divalent metal transporters (FeoB or ZIP). After reoxidation, iron can be taken up by the high-affinity permease Ftr1.
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Affiliation(s)
- Robert Sutak
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czechia
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10
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Benavides M, Arístegui J. Untreated sewage outfalls do not promote Trichodesmium blooms in the coasts of the Canary Islands. Sci Rep 2020; 10:18386. [PMID: 33110228 PMCID: PMC7591472 DOI: 10.1038/s41598-020-75447-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 09/30/2020] [Indexed: 11/10/2022] Open
Abstract
During the summer of 2017, recurrent extensive blooms of the diazotrophic cyanobacterium Trichodesmium invaded the beaches and coastal waters of the Canary Islands, causing great social alarm. Some local media and public sectors ascribed, without any strong scientific evidence, the origin and reactivation of these blooms to untreated sewage outfalls distributed along the coasts. In order to test whether sewage outfalls could have any influence on the metabolic activity of Trichodesmium, we performed 13C and 15N2 uptake experiments with colonies experiencing three different bloom development stages, incubated both with clear seawater and sewage water from an outfall south of Gran Canaria island. Our results showed that sewage outfalls did not promote any increase in dinitrogen (N2) fixation in Trichodesmium, supporting the hypothesis that decaying blooms were generated offshore and transported shoreward by local currents and winds, accumulating mostly leeward of the islands. The combination of unusually warm seawater temperatures, enhanced and sustained stratification of the upper water column and recurrent dust deposition events would have favored the development of the Trichodesmium blooms, which lasted for at least four months.
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Affiliation(s)
- Mar Benavides
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Javier Arístegui
- Instituto de Oceanografía y Cambio Global, Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain.
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11
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Thirumurthy MA, Hitchcock A, Cereda A, Liu J, Chavez MS, Doss BL, Ros R, El-Naggar MY, Heap JT, Bibby TS, Jones AK. Type IV Pili-Independent Photocurrent Production by the Cyanobacterium Synechocystis sp. PCC 6803. Front Microbiol 2020; 11:1344. [PMID: 32714295 PMCID: PMC7344198 DOI: 10.3389/fmicb.2020.01344] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/26/2020] [Indexed: 11/13/2022] Open
Abstract
Biophotovoltaic devices utilize photosynthetic organisms such as the model cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis) to generate current for power or hydrogen production from light. These devices have been improved by both architecture engineering and genetic engineering of the phototrophic organism. However, genetic approaches are limited by lack of understanding of cellular mechanisms of electron transfer from internal metabolism to the cell exterior. Type IV pili have been implicated in extracellular electron transfer (EET) in some species of heterotrophic bacteria. Furthermore, conductive cell surface filaments have been reported for cyanobacteria, including Synechocystis. However, it remains unclear whether these filaments are type IV pili and whether they are involved in EET. Herein, a mediatorless electrochemical setup is used to compare the electrogenic output of wild-type Synechocystis to that of a ΔpilD mutant that cannot produce type IV pili. No differences in photocurrent, i.e., current in response to illumination, are detectable. Furthermore, measurements of individual pili using conductive atomic force microscopy indicate these structures are not conductive. These results suggest that pili are not required for EET by Synechocystis, supporting a role for shuttling of electrons via soluble redox mediators or direct interactions between the cell surface and extracellular substrates.
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Affiliation(s)
| | - Andrew Hitchcock
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, United Kingdom
| | - Angelo Cereda
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
| | - Jiawei Liu
- Department of Physics, Arizona State University, Tempe, AZ, United States
| | - Marko S. Chavez
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, United States
| | - Bryant L. Doss
- Department of Physics, Arizona State University, Tempe, AZ, United States
| | - Robert Ros
- Department of Physics, Arizona State University, Tempe, AZ, United States
| | - Mohamed Y. El-Naggar
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, United States
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
- Department of Chemistry, University of Southern California, Los Angeles, CA, United States
| | - John T. Heap
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, London, United Kingdom
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Thomas S. Bibby
- Ocean and Earth Science, University of Southampton, Southampton, United Kingdom
| | - Anne K. Jones
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
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12
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Marine nitrogen fixers mediate a low latitude pathway for atmospheric CO 2 drawdown. Nat Commun 2019; 10:4611. [PMID: 31601810 PMCID: PMC6787065 DOI: 10.1038/s41467-019-12549-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 09/16/2019] [Indexed: 02/02/2023] Open
Abstract
Roughly a third (~30 ppm) of the carbon dioxide (CO2) that entered the ocean during ice ages is attributed to biological mechanisms. A leading hypothesis for the biological drawdown of CO2 is iron (Fe) fertilisation of the high latitudes, but modelling efforts attribute at most 10 ppm to this mechanism, leaving ~20 ppm unexplained. We show that an Fe-induced stimulation of dinitrogen (N2) fixation can induce a low latitude drawdown of 7–16 ppm CO2. This mechanism involves a closer coupling between N2 fixers and denitrifiers that alleviates widespread nitrate limitation. Consequently, phosphate utilisation and carbon export increase near upwelling zones, causing deoxygenation and deeper carbon injection. Furthermore, this low latitude mechanism reproduces the regional patterns of organic δ15N deposited in glacial sediments. The positive response of marine N2 fixation to dusty ice age conditions, first proposed twenty years ago, therefore compliments high latitude changes to amplify CO2 drawdown. Iron fertilisation of the high latitude oceans is a well-established biological mechanism to explain the ice age drawdown of atmospheric CO2, yet modelling has so far struggled to account for a sufficient drawdown via this mechanism. Here, the authors propose that N2 fixers, which inhabit the lower latitude ocean, made a significant contribution to CO2 drawdown and so amplified the global response to iron fertilisation during ice ages.
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Zhang F, Hong H, Kranz SA, Shen R, Lin W, Shi D. Proteomic responses to ocean acidification of the marine diazotroph Trichodesmium under iron-replete and iron-limited conditions. PHOTOSYNTHESIS RESEARCH 2019; 142:17-34. [PMID: 31077001 DOI: 10.1007/s11120-019-00643-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 04/30/2019] [Indexed: 05/19/2023]
Abstract
Growth and dinitrogen (N2) fixation of the globally important diazotrophic cyanobacteria Trichodesmium are often limited by iron (Fe) availability in surface seawaters. To systematically examine the combined effects of Fe limitation and ocean acidification (OA), T. erythraeum strain IMS101 was acclimated to both Fe-replete and Fe-limited concentrations under ambient and acidified conditions. Proteomic analysis showed that OA affected a wider range of proteins under Fe-limited conditions compared to Fe-replete conditions. OA also led to an intensification of Fe deficiency in key cellular processes (e.g., photosystem I and chlorophyll a synthesis) in already Fe-limited T. erythraeum. This is a result of reallocating Fe from these processes to Fe-rich nitrogenase to compensate for the suppressed N2 fixation. To alleviate the Fe shortage, the diazotroph adopts a series of Fe-based economic strategies (e.g., upregulating Fe acquisition systems for organically complexed Fe and particulate Fe, replacing ferredoxin by flavodoxin, and using alternative electron flow pathways to produce ATP). This was more pronounced under Fe-limited-OA conditions than under Fe limitation only. Consequently, OA resulted in a further decrease of N2- and carbon-fixation rates in Fe-limited T. erythraeum. In contrast, Fe-replete T. erythraeum induced photosystem I (PSI) expression to potentially enhance the PSI cyclic flow for ATP production to meet the higher demand for energy to cope with the stress caused by OA. Our study provides mechanistic insight into the holistic response of the globally important N2-fixing marine cyanobacteria Trichodesmium to acidified and Fe-limited conditions of future oceans.
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Affiliation(s)
- Futing Zhang
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Haizheng Hong
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China
- Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen University, Xiamen, Fujian, People's Republic of China
- College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Sven A Kranz
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Rong Shen
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Wenfang Lin
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Dalin Shi
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China.
- Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen University, Xiamen, Fujian, People's Republic of China.
- College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, People's Republic of China.
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Selective collection of iron-rich dust particles by natural Trichodesmium colonies. ISME JOURNAL 2019; 14:91-103. [PMID: 31551530 PMCID: PMC6908701 DOI: 10.1038/s41396-019-0505-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 07/31/2019] [Accepted: 08/09/2019] [Indexed: 02/07/2023]
Abstract
Dust is an important iron (Fe) source to the ocean, but its utilization by phytoplankton is constrained by rapid sinking and slow dissolution dust-bound iron (dust-Fe). Colonies of the globally important cyanobacterium, Trichodesmium, overcome these constraints by efficient dust capturing and active dust-Fe dissolution. In this study we examined the ability of Trichodesmium colonies to maximize their Fe supply from dust by selectively collecting Fe-rich particles. Testing for selectivity in particle collection, we supplied ~600 individual colonies, collected on multiple days from the Gulf of Aqaba, with natural dust and silica minerals that were either cleaned of or coated with Fe. Using a stereoscope, we counted the number of particles retained by each colony shortly after addition and following 24 h incubation with particles, and documented translocation of particles to the colony core. We observed a strong preference for Fe-rich particles over Fe-free particles in all tested parameters. Moreover, some colonies discarded the Fe-free particles they initially collected. The preferred collection of Fe-rich particles and disposal of Fe-free particles suggest that Trichodesmium can sense Fe and selectively choose Fe-rich dust particles. This ability assists Trichodesmium obtain Fe from dust and facilitate its growth and subsequent contribution to nutrient cycling and productivity in the ocean.
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Eichner M, Basu S, Gledhill M, de Beer D, Shaked Y. Hydrogen Dynamics in Trichodesmium Colonies and Their Potential Role in Mineral Iron Acquisition. Front Microbiol 2019; 10:1565. [PMID: 31354665 PMCID: PMC6636555 DOI: 10.3389/fmicb.2019.01565] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 06/24/2019] [Indexed: 12/14/2022] Open
Abstract
N2-fixing cyanobacteria mediate H2 fluxes through the opposing processes of H2 evolution, which is a by-product of the N2 fixation reaction, and H2 uptake, which is driven by uptake hydrogenases. Here, we used microelectrodes to characterize H2 and O2 dynamics in single natural colonies of the globally important N2 fixer Trichodesmium collected from the Gulf of Eilat. We observed gradually changing H2 dynamics over the course of the day, including both net H2 evolution and net H2 uptake, as well as large differences in H2 fluxes between individual colonies. Net H2 uptake was observed in colonies amended with H2 in both light and dark. Net H2 evolution was recorded in the light only, reflecting light-dependent N2 fixation coupled to H2 evolution. Both net H2 evolution and H2 uptake rates were higher before 2 pm than later in the day. These pronounced H2 dynamics in the morning coincided with strong net O2 uptake and the previously reported diel peak in N2 fixation. Later in the afternoon, when photosynthesis rates determined by O2 measurements were highest, and N2 fixation rates decrease according to previous studies, the H2 dynamics were also less pronounced. Thus, the observed diel variations in H2 dynamics reflect diel changes in the rates of O2 consumption and N2 fixation. Remarkably, the presence of H2 strongly stimulated the uptake of mineral iron by natural colonies. The magnitude of this effect was dependent on the time of day, with the strongest response in incubations that started before 2 pm, i.e., the period that covered the time of highest uptake hydrogenase activity. Based on these findings, we propose that by providing an electron source for mineral iron reduction in N2-fixing cells, H2 may contribute to iron uptake in Trichodesmium colonies.
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Affiliation(s)
- Meri Eichner
- Microsensor Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Subhajit Basu
- The Freddy & Nadine Herrmann Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
| | - Martha Gledhill
- GEOMAR Helmholtz Center for Ocean Research Kiel, Kiel, Germany
| | - Dirk de Beer
- Microsensor Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Yeala Shaked
- The Freddy & Nadine Herrmann Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
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Frischkorn KR, Haley ST, Dyhrman ST. Transcriptional and Proteomic Choreography Under Phosphorus Deficiency and Re-supply in the N 2 Fixing Cyanobacterium Trichodesmium erythraeum. Front Microbiol 2019; 10:330. [PMID: 30891009 PMCID: PMC6411698 DOI: 10.3389/fmicb.2019.00330] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/08/2019] [Indexed: 01/27/2023] Open
Abstract
The N2 fixing cyanobacterium Trichodesmium is a critically important organism in oligotrophic marine ecosystems, supplying “new” nitrogen (N) to the otherwise N-poor tropical and subtropical regions where it occurs. Low concentrations of phosphorus (P) in these regions can constrain Trichodesmium distribution and N2 fixation rates. Physiological characterization of a single species in a mixed community can be challenging, and ‘omic approaches are increasingly important tools for tracking nutritional physiology in a taxon-specific manner. As such, studies examining the dynamics of gene and protein markers of physiology (e.g., nutrient stress) are critical for the application and interpretation of such ‘omic data in situ. Here we leveraged combined transcriptomics, proteomics, and enzyme activity assays to track the physiological response of Trichodesmium erythraeum IMS101 to P deficiency and subsequent P re-supply over 72 h of sampling. P deficiency resulted in differential gene expression, protein abundance, and enzyme activity that highlighted a synchronous shift in P physiology with increases in the transcripts and corresponding proteins for hydrolyzing organic phosphorus, taking up phosphate with higher affinity, and modulating intracellular P demand. After P deficiency was alleviated, gene expression of these biomarkers was reduced to replete levels within 4 h of P amendment. A number of these gene biomarkers were adjacent to putative pho boxes and their expression patterns were similar to a sphR response regulator. Protein products of the P deficiency biomarkers were slow to decline, with 84% of the original P deficient protein set still significantly differentially expressed after 72 h. Alkaline phosphatase activity tracked with proteins for this enzyme. With the rapid turnover time of transcripts, they appear to be good biomarkers of a P stress phenotype, whereas proteins, with a slower turnover time, may better reflect cellular activities. These results highlight the importance of validating and pairing transcriptome and proteome data that can be applied to physiological studies of key species in situ.
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Affiliation(s)
- Kyle R Frischkorn
- Department of Earth and Environmental Sciences, Columbia University, New York, NY, United States.,Lamont-Doherty Earth Observatory, Palisades, NY, United States
| | - Sheean T Haley
- Lamont-Doherty Earth Observatory, Palisades, NY, United States
| | - Sonya T Dyhrman
- Department of Earth and Environmental Sciences, Columbia University, New York, NY, United States.,Lamont-Doherty Earth Observatory, Palisades, NY, United States
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