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Lapointe A, Kocademir M, Bergman P, Ragupathy IC, Laumann M, Underwood GJC, Zumbusch A, Spiteller D, Kroth PG. Characterization of polyphosphate dynamics in the widespread freshwater diatom Achnanthidium minutissimum under varying phosphorus supplies. JOURNAL OF PHYCOLOGY 2024; 60:624-638. [PMID: 38163284 DOI: 10.1111/jpy.13423] [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: 03/27/2023] [Revised: 11/11/2023] [Accepted: 12/01/2023] [Indexed: 01/03/2024]
Abstract
Polyphosphates (polyP) are ubiquitous biomolecules that play a multitude of physiological roles in many cells. We have studied the presence and role of polyP in a unicellular alga, the freshwater diatom Achnanthidium minutissimum. This diatom stores up to 2.0 pg·cell-1 of polyP, with chain lengths ranging from 130 to 500 inorganic phosphate units (Pi). We applied energy dispersive X-ray spectroscopy, Raman/fluorescence microscopy, and biochemical assays to localize and characterize the intracellular polyP granules that were present in large apical vacuoles. We investigated the fate of polyP in axenic A. minutissimum cells grown under phosphorus (P), replete (P(+)), or P deplete (P(-)) cultivation conditions and observed that in the absence of exogenous P, A. minutissimum rapidly utilizes their internal polyP reserves, maintaining their intrinsic growth rates for up to 8 days. PolyP-depleted A. minutissimum cells rapidly took up exogenous P a few hours after Pi resupply and generated polyP three times faster than cells that were not initially subjected to P limitation. Accordingly, we propose that A. minutissimum deploys a succession of acclimation strategies regarding polyP dynamics where the production or consumption of polyP plays a central role in the homeostasis of the diatom.
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Affiliation(s)
- Adrien Lapointe
- Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Paavo Bergman
- Electron-Microscopy Centre, University of Konstanz, Konstanz, Germany
| | | | - Michael Laumann
- Electron-Microscopy Centre, University of Konstanz, Konstanz, Germany
| | | | - Andreas Zumbusch
- Department of Chemistry, University of Konstanz, Konstanz, Germany
| | - Dieter Spiteller
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Peter G Kroth
- Department of Biology, University of Konstanz, Konstanz, Germany
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Gleich SJ, Hu SK, Krinos AI, Caron DA. Protistan community composition and metabolism in the North Pacific Subtropical Gyre: Influences of mesoscale eddies and depth. Environ Microbiol 2024; 26:e16556. [PMID: 38081167 DOI: 10.1111/1462-2920.16556] [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: 08/11/2023] [Accepted: 11/27/2023] [Indexed: 01/30/2024]
Abstract
Marine protists and their metabolic activities are intricately tied to the cycling of nutrients and the flow of energy through microbial food webs. Physiochemical changes in the environment, such as those that result from mesoscale eddies, may impact protistan communities, but the effects that such changes have on protists are poorly known. A metatranscriptomic study was conducted to investigate how eddies affected protists at adjacent cyclonic and anticyclonic eddy sites in the oligotrophic ocean at four depths from 25 to 250 m. Eddy polarity impacted protists at all depths sampled, although the effects of eddy polarity were secondary to the impact of depth across the depth range. Eddy-induced vertical shifts in the water column yielded differences in the cyclonic and anticyclonic eddy protistan communities, and these differences were the most pronounced at and just below the deep chlorophyll maximum. An analysis of transcripts associated with protistan nutritional physiology at 150 m revealed that cyclonic eddies may support a more heterotrophic community, while anticyclonic eddies promote a more phototrophic community. The results of this study indicate that eddies alter the metabolism of protists particularly in the lower euphotic zone and may therefore impact carbon export from the euphotic zone.
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Affiliation(s)
- Samantha J Gleich
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Sarah K Hu
- Department of Oceanography, Texas A&M University, College Station, Texas, USA
| | - Arianna I Krinos
- MIT-WHOI Joint Program in Oceanography and Applied Ocean Science and Engineering, Cambridge and Woods Hole, Cambridge, Massachusetts, USA
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
- Department of Earth, Atmospheric, and Planetary Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - David A Caron
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
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Brunson JK, Thukral M, Ryan JP, Anderson CR, Kolody BC, James C, Chavez FP, Leaw CP, Rabines AJ, Venepally P, Zheng H, Kudela RM, Smith GJ, Moore BS, Allen AE. Molecular Forecasting of Domoic Acid during a Pervasive Toxic Diatom Bloom. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.02.565333. [PMID: 37961417 PMCID: PMC10635071 DOI: 10.1101/2023.11.02.565333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
In 2015, the largest recorded harmful algal bloom (HAB) occurred in the Northeast Pacific, causing nearly 100 million dollars in damages to fisheries and killing many protected marine mammals. Dominated by the toxic diatom Pseudo-nitzschia australis , this bloom produced high levels of the neurotoxin domoic acid (DA). Through molecular and transcriptional characterization of 52 near-weekly phytoplankton net-tow samples collected at a bloom hotspot in Monterey Bay, California, we identified active transcription of known DA biosynthesis ( dab ) genes from the three identified toxigenic species, including P. australis as the primary origin of toxicity. Elevated expression of silicon transporters ( sit1 ) during the bloom supports the previously hypothesized role of dissolved silica (Si) exhaustion in contributing to bloom physiology and toxicity. We find that co-expression of the dabA and sit1 genes serves as a robust predictor of DA one week in advance, potentially enabling the forecasting of DA-producing HABs. We additionally present evidence that low levels of iron could have co-limited the diatom population along with low Si. Iron limitation represents a previously unrecognized driver of both toxin production and ecological success of the low iron adapted Pseudo-nitzschia genus during the 2015 bloom, and increasing pervasiveness of iron limitation may fuel the escalating magnitude and frequency of toxic Pseudo-nitzschia blooms globally. Our results advance understanding of bloom physiology underlying toxin production, bloom prediction, and the impact of global change on toxic blooms. Significance Pseudo-nitzschia diatoms form oceanic harmful algal blooms that threaten human health through production of the neurotoxin domoic acid (DA). DA biosynthetic gene expression is hypothesized to control DA production in the environment, yet what regulates expression of these genes is yet to be discovered. In this study, we uncovered expression of DA biosynthesis genes by multiple toxigenic Pseudo-nitzschia species during an economically impactful bloom along the North American West Coast, and identified genes that predict DA in advance of its production. We discovered that iron and silica co-limitation restrained the bloom and likely promoted toxin production. This work suggests that increasing iron limitation due to global change may play a previously unrecognized role in driving bloom frequency and toxicity.
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Yee DP, Samo TJ, Abbriano RM, Shimasaki B, Vernet M, Mayali X, Weber PK, Mitchell BG, Hildebrand M, Decelle J, Tresguerres M. The V-type ATPase enhances photosynthesis in marine phytoplankton and further links phagocytosis to symbiogenesis. Curr Biol 2023; 33:2541-2547.e5. [PMID: 37263270 PMCID: PMC10326425 DOI: 10.1016/j.cub.2023.05.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 03/20/2023] [Accepted: 05/09/2023] [Indexed: 06/03/2023]
Abstract
Diatoms, dinoflagellates, and coccolithophores are dominant groups of marine eukaryotic phytoplankton that are collectively responsible for the majority of primary production in the ocean.1 These phytoplankton contain additional intracellular membranes around their chloroplasts, which are derived from ancestral engulfment of red microalgae by unicellular heterotrophic eukaryotes that led to secondary and tertiary endosymbiosis.2 However, the selectable evolutionary advantage of these membranes and the physiological significance for extant phytoplankton remain poorly understood. Since intracellular digestive vacuoles are ubiquitously acidified by V-type H+-ATPase (VHA),3 proton pumps were proposed to acidify the microenvironment around secondary chloroplasts to promote the dehydration of dissolved inorganic carbon (DIC) into CO2, thus enhancing photosynthesis.4,5 We report that VHA is localized around the chloroplasts of centric diatoms and that VHA significantly contributes to their photosynthesis across a wide range of oceanic irradiances. Similar results in a pennate diatom, dinoflagellate, and coccolithophore, but not green or red microalgae, imply the co-option of phagocytic VHA activity into a carbon-concentrating mechanism (CCM) is common to secondary endosymbiotic phytoplankton. Furthermore, analogous mechanisms in extant photosymbiotic marine invertebrates6,7,8 provide functional evidence for an adaptive advantage throughout the transition from endosymbiosis to symbiogenesis. Based on the contribution of diatoms to ocean biogeochemical cycles, VHA-mediated enhancement of photosynthesis contributes at least 3.5 Gtons of fixed carbon per year (or 7% of primary production in the ocean), providing an example of a symbiosis-derived evolutionary innovation with global environmental implications.
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Affiliation(s)
- Daniel P Yee
- Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Cell and Plant Physiology Laboratory, University of Grenoble Alpes, CNRS, CEA, INRAE, and IRIG, 17 Avenue des Martyrs, Grenoble 38054, Auvergne-Rhone-Alpes, France.
| | - Ty J Samo
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, USA
| | - Raffaela M Abbriano
- Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Bethany Shimasaki
- Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Maria Vernet
- Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Xavier Mayali
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, USA
| | - Peter K Weber
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, USA
| | - B Greg Mitchell
- Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Mark Hildebrand
- Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Johan Decelle
- Cell and Plant Physiology Laboratory, University of Grenoble Alpes, CNRS, CEA, INRAE, and IRIG, 17 Avenue des Martyrs, Grenoble 38054, Auvergne-Rhone-Alpes, France
| | - Martin Tresguerres
- Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
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Exocytosis of the silicified cell wall of diatoms involves extensive membrane disintegration. Nat Commun 2023; 14:480. [PMID: 36717559 PMCID: PMC9886994 DOI: 10.1038/s41467-023-36112-z] [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: 08/04/2021] [Accepted: 01/16/2023] [Indexed: 01/31/2023] Open
Abstract
Diatoms are unicellular algae characterized by silica cell walls. These silica elements are known to be formed intracellularly in membrane-bound silica deposition vesicles and exocytosed after completion. How diatoms maintain membrane homeostasis during the exocytosis of these large and rigid silica elements remains unknown. Here we study the membrane dynamics during cell wall formation and exocytosis in two model diatom species, using live-cell confocal microscopy, transmission electron microscopy and cryo-electron tomography. Our results show that during its formation, the mineral phase is in tight association with the silica deposition vesicle membranes, which form a precise mold of the delicate geometrical patterns. We find that during exocytosis, the distal silica deposition vesicle membrane and the plasma membrane gradually detach from the mineral and disintegrate in the extracellular space, without any noticeable endocytic retrieval or extracellular repurposing. We demonstrate that within the cell, the proximal silica deposition vesicle membrane becomes the new barrier between the cell and its environment, and assumes the role of a new plasma membrane. These results provide direct structural observations of diatom silica exocytosis, and point to an extraordinary mechanism in which membrane homeostasis is maintained by discarding, rather than recycling, significant membrane patches.
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Brownlee C, Helliwell KE, Meeda Y, McLachlan D, Murphy EA, Wheeler GL. Regulation and integration of membrane transport in marine diatoms. Semin Cell Dev Biol 2023; 134:79-89. [PMID: 35305902 DOI: 10.1016/j.semcdb.2022.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 02/18/2022] [Accepted: 03/04/2022] [Indexed: 12/27/2022]
Abstract
Diatoms represent one of the most successful groups of marine phytoplankton and are major contributors to ocean biogeochemical cycling. They have colonized marine, freshwater and ice environments and inhabit all regions of the World's oceans, from poles to tropics. Their success is underpinned by a remarkable ability to regulate their growth and metabolism during nutrient limitation and to respond rapidly when nutrients are available. This requires precise regulation of membrane transport and nutrient acquisition mechanisms, integration of nutrient sensing mechanisms and coordination of different transport pathways. This review outlines transport mechanisms involved in acquisition of key nutrients (N, C, P, Si, Fe) by marine diatoms, illustrating their complexity, sophistication and multiple levels of control.
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Affiliation(s)
- Colin Brownlee
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK; School of Ocean and Earth Sciences, University of Southampton, Southampton SO14 3ZH, UK
| | - Katherine E Helliwell
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK; Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK
| | - Yasmin Meeda
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
| | - Deirdre McLachlan
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK; School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Eleanor A Murphy
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
| | - Glen L Wheeler
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
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Bhattacharjya R, Tiwari A, Marella TK, Bansal H, Srivastava S. New paradigm in diatom omics and genetic manipulation. BIORESOURCE TECHNOLOGY 2021; 325:124708. [PMID: 33487514 DOI: 10.1016/j.biortech.2021.124708] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 06/12/2023]
Abstract
Diatoms are one of the most heterogeneous eukaryotic plankton known for regulating earth's biogeochemical cycles and maintaining the marine ecosystems ever since the late Eocene epoch. The advent of multidisciplinary omics approach has both epitomized and revolutionized the nature of their chimeric genetic toolkit, ecophysiology, and metabolic adaptability as well as their interaction with other communities. In addition, advanced functional annotation of transcriptomic and proteomic data using cutting edge bioinformatics tools together with high-resolution genome-scale mathematical modeling has effectively proven as the catapult in solving genetic bottlenecks in microbial as well as diatom exploration. In this review, a corroborative summation of the robust work done in manipulating, engineering, and sequencing of the diatom genomes besides underpinning the holistic application of omics in transcription and translation has been discussed in order to shrewd their multifarious novel potential in the field of biotechnology and provide an insight into their dynamic evolutionary relevance.
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Affiliation(s)
- Raya Bhattacharjya
- Diatom Research Laboratory, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh 201313, India
| | - Archana Tiwari
- Diatom Research Laboratory, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh 201313, India.
| | - Thomas Kiran Marella
- Algae Biomass Energy System Development Research Center (ABES), Tennodai, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Hina Bansal
- Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh 201313, India
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Turnšek J, Brunson JK, Viedma MDPM, Deerinck TJ, Horák A, Oborník M, Bielinski VA, Allen AE. Proximity proteomics in a marine diatom reveals a putative cell surface-to-chloroplast iron trafficking pathway. eLife 2021; 10:e52770. [PMID: 33591270 PMCID: PMC7972479 DOI: 10.7554/elife.52770] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/15/2021] [Indexed: 12/16/2022] Open
Abstract
Iron is a biochemically critical metal cofactor in enzymes involved in photosynthesis, cellular respiration, nitrate assimilation, nitrogen fixation, and reactive oxygen species defense. Marine microeukaryotes have evolved a phytotransferrin-based iron uptake system to cope with iron scarcity, a major factor limiting primary productivity in the global ocean. Diatom phytotransferrin is endocytosed; however, proteins downstream of this environmentally ubiquitous iron receptor are unknown. We applied engineered ascorbate peroxidase APEX2-based subcellular proteomics to catalog proximal proteins of phytotransferrin in the model marine diatom Phaeodactylum tricornutum. Proteins encoded by poorly characterized iron-sensitive genes were identified including three that are expressed from a chromosomal gene cluster. Two of them showed unambiguous colocalization with phytotransferrin adjacent to the chloroplast. Further phylogenetic, domain, and biochemical analyses suggest their involvement in intracellular iron processing. Proximity proteomics holds enormous potential to glean new insights into iron acquisition pathways and beyond in these evolutionarily, ecologically, and biotechnologically important microalgae.
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Affiliation(s)
- Jernej Turnšek
- Biological and Biomedical Sciences, The Graduate School of Arts and Sciences, Harvard UniversityCambridgeUnited States
- Department of Systems Biology, Harvard Medical SchoolBostonUnited States
- Wyss Institute for Biologically Inspired Engineering, Harvard UniversityBostonUnited States
- Integrative Oceanography Division, Scripps Institution of Oceanography, University of California San DiegoLa JollaUnited States
- Center for Research in Biological Systems, University of California San DiegoLa JollaUnited States
- Microbial and Environmental Genomics, J. Craig Venter InstituteLa JollaUnited States
| | - John K Brunson
- Microbial and Environmental Genomics, J. Craig Venter InstituteLa JollaUnited States
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San DiegoLa JollaUnited States
| | | | - Thomas J Deerinck
- National Center for Microscopy and Imaging Research, University of California San DiegoLa JollaUnited States
| | - Aleš Horák
- Biology Centre CAS, Institute of ParasitologyČeské BudějoviceCzech Republic
- University of South Bohemia, Faculty of ScienceČeské BudějoviceCzech Republic
| | - Miroslav Oborník
- Biology Centre CAS, Institute of ParasitologyČeské BudějoviceCzech Republic
- University of South Bohemia, Faculty of ScienceČeské BudějoviceCzech Republic
| | - Vincent A Bielinski
- Synthetic Biology and Bioenergy, J. Craig Venter InstituteLa JollaUnited States
| | - Andrew Ellis Allen
- Integrative Oceanography Division, Scripps Institution of Oceanography, University of California San DiegoLa JollaUnited States
- Microbial and Environmental Genomics, J. Craig Venter InstituteLa JollaUnited States
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