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Yu Z, Wang Z, Liu L. Electrophysiological techniques in marine microalgae study: A new perspective for harmful algal bloom (HAB) research. HARMFUL ALGAE 2024; 134:102629. [PMID: 38705615 DOI: 10.1016/j.hal.2024.102629] [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: 01/07/2024] [Revised: 04/11/2024] [Accepted: 04/15/2024] [Indexed: 05/07/2024]
Abstract
Electrophysiological techniques, by measuring bioelectrical signals and ion channel activities in tissues and cells, are now widely utilized to study ion channel-related physiological functions and their underlying mechanisms. Electrophysiological techniques have been extensively employed in the investigation of animals, plants, and microorganisms; however, their application in marine algae lags behind that in other organisms. In this paper, we present an overview of current electrophysiological techniques applicable to algae while reviewing the historical usage of such techniques in this field. Furthermore, we explore the potential specific applications of electrophysiological technology in harmful algal bloom (HAB) research. The application prospects in the studies of stress tolerance, competitive advantage, nutrient absorption, toxin synthesis and secretion by HAB microalgae are discussed and anticipated herein with the aim of providing novel perspectives on HAB investigations.
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Affiliation(s)
- Zhiming Yu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory of Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266237, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China.
| | - Zhongshi Wang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory of Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266237, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Lidong Liu
- The Djavad Mowafaghian Centre for Brian Health and Department of Medicine, University of British Columbia, Vancouver, BC, Canada
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2
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Chen XW, Chen H, Zhao HL, Li DW, Ou LJ. Triazine herbicide reduced the toxicity of the harmful dinoflagellate Karenia mikimotoi by impairing its photosynthetic systems. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 269:115740. [PMID: 38042131 DOI: 10.1016/j.ecoenv.2023.115740] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/04/2023]
Abstract
Triazine herbicides are common contaminants in coastal waters, and they are recognized as inhibitors of photosystem II, causing significant hinderance to the growth and reproduction of phytoplankton. However, the influence of these herbicides on microalgal toxin production remains unclear. This study aimed to examine this relationship by conducting a comprehensive physiological and 4D label-free quantitative proteomic analysis on the harmful dinoflagellate Karenia mikimotoi in the presence of the triazine herbicide dipropetryn. The findings demonstrated a significant decrease in photosynthetic activity and pigment content, as well as reduced levels of unsaturated fatty acids, reactive oxygen species (ROS), and hemolytic toxins in K. mikimotoi when exposed to dipropetryn. The proteomic analysis revealed a down-regulation in proteins associated with photosynthesis, ROS response, and energy metabolism, such as fatty acid biosynthesis, chlorophyll metabolism, and nitrogen metabolism. In contrast, an up-regulation of proteins related to energy-producing processes, such as fatty acid β-oxidation, glycolysis, and the tricarboxylic acid cycle, was observed. This study demonstrated that dipropetryn disrupts the photosynthetic systems of K. mikimotoi, resulting in a notable decrease in algal toxin production. These findings provide valuable insights into the underlying mechanisms of toxin production in toxigenic microalgae and explore the potential effect of herbicide pollution on harmful algal blooms in coastal environments.
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Affiliation(s)
- Xiang-Wu Chen
- College of Life Science and Technology and Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, Jinan University, Guangzhou, China
| | - Heng Chen
- College of Life Science and Technology and Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, Jinan University, Guangzhou, China
| | - Hai-Ling Zhao
- College of Life Science and Technology and Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, Jinan University, Guangzhou, China
| | - Da-Wei Li
- College of Life Science and Technology and Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, Jinan University, Guangzhou, China.
| | - Lin-Jian Ou
- College of Life Science and Technology and Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, Jinan University, Guangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China.
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3
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Liu X, Chen J, Du H, Liu Z, Du H, Rashid A, Wang Y, Ma W, Wang S. Resolving the dynamics of chrysolaminarin regulation in a marine diatom: A physiological and transcriptomic study. Int J Biol Macromol 2023; 252:126361. [PMID: 37591430 DOI: 10.1016/j.ijbiomac.2023.126361] [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: 02/21/2023] [Revised: 08/01/2023] [Accepted: 08/14/2023] [Indexed: 08/19/2023]
Abstract
Diatom containing different active biological macromolecules are thought to be an excellent microbial cell factory. Phaeodactylum tricornutum, a model diatom, is a superb chassis organism accumulating chrysolaminarin with important bioactivities. However, the characteristic of chrysolaminarin accumulation and molecular mechanism of the fluctuated chrysolaminarin in diatom are still unknown. In this study, physiological data and transcriptomic analysis were carried out to clarify the mechanism involved in chrysolaminarin fluctuation. The results showed that chrysolaminarin content fluctuated, from 7.41 % dry weight (DW) to 40.01 % DW during one light/dark cycle, increase by day and decrease by night. The similar fluctuated characteristic was also observed in neutral lipid content. Genes related to the biosynthesis of chrysolaminarin and neutral lipid were up-regulated at the beginning of light-phase, explaining the accumulation of these biological macromolecules. Furthermore, genes involved in carbohydrate degradation, cell cycle, DNA replication and mitochondria-localized β-oxidation were up-regulated at the end of light phase and at the beginning of dark phase hinting an energy transition of carbohydrate to cell division during the dark period. Totally, our findings provide important information for the regulatory mechanism in the diurnal fluctuation of chrysolaminarin. It would also be of great help for the mass production of economical chrysolaminarin in marine diatom.
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Affiliation(s)
- Xiaojuan Liu
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou 515063, Guangdong, China
| | - Jichen Chen
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou 515063, Guangdong, China
| | - Hong Du
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou 515063, Guangdong, China.
| | - Zidong Liu
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou 515063, Guangdong, China
| | - Hua Du
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou 515063, Guangdong, China
| | - Azhar Rashid
- Department of Environmental Sciences, The University of Haripur, Haripur 22620, Pakistan
| | - Yuwen Wang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou 515063, Guangdong, China
| | - Wanying Ma
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou 515063, Guangdong, China
| | - Shuqi Wang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou 515063, Guangdong, China
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4
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Carnicer O, Hu YY, Ebenezer V, Irwin AJ, Finkel ZV. Genomic architecture constrains macromolecular allocation in dinoflagellates. Protist 2023; 174:125992. [PMID: 37738738 DOI: 10.1016/j.protis.2023.125992] [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: 04/13/2023] [Revised: 07/21/2023] [Accepted: 09/11/2023] [Indexed: 09/24/2023]
Abstract
Dinoflagellate genomes have a unique architecture that may constrain their physiological and biochemical responsiveness to environmental stressors. Here we quantified how nitrogen (N) starvation influenced macromolecular allocation and C:N:P of three photosynthetic marine dinoflagellates, representing different taxonomic classes and genome sizes. Dinoflagellates respond to nitrogen starvation by decreasing cellular nitrogen, protein and RNA content, but unlike many other eukaryotic phytoplankton examined RNA:protein is invariant. Additionally, 2 of the 3 species exhibit increases in cellular phosphorus and very little change in cellular carbon with N-starvation. As a consequence, N starvation induces moderate increases in C:N, but extreme decreases in N:P and C:P, relative to diatoms. Dinoflagellate DNA content relative to total C, N and P is much higher than similar sized diatoms, but similar to very small photosynthetic picoeukaryotes such as Ostreococcus. In aggregate these results indicate the accumulation of phosphate stores may be an important strategy employed by dinoflagellates to meet P requirements associated with the maintenance and replication of their large genomes.
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Affiliation(s)
- Olga Carnicer
- Department of Oceanography, Dalhousie University, Halifax, Canada
| | - Ying-Yu Hu
- Department of Oceanography, Dalhousie University, Halifax, Canada
| | - Vinitha Ebenezer
- Department of Oceanography, Dalhousie University, Halifax, Canada
| | - Andrew J Irwin
- Department of Mathematics & Statistics, Dalhousie University, Halifax, Canada
| | - Zoe V Finkel
- Department of Oceanography, Dalhousie University, Halifax, Canada.
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Ahn SH, Glibert PM, Heil CA. In hot water: Interactions of temperature, nitrogen form and availability and photosynthetic and nitrogen uptake responses in natural Karenia brevis populations. HARMFUL ALGAE 2023; 129:102519. [PMID: 37951619 DOI: 10.1016/j.hal.2023.102519] [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: 03/13/2023] [Revised: 08/30/2023] [Accepted: 09/29/2023] [Indexed: 11/14/2023]
Abstract
During 2020-2021, an unusually prolonged bloom of the toxigenic dinoflagellate Karenia brevis persisted for more than 12 months along the Gulf coast of Florida, resulting in severe environmental effects. Motivated by the possibility that unusual nutrient conditions existed during summer 2021, the short-term interactions of temperature, nitrogen (N) forms (ammonium (NH4+), nitrate (NO3-), and urea) and availability on photosynthesis-irradiance responses and N uptake rates were examined in summer 2021 and compared to such responses from the earlier winter. Winter samples were exposed to temperatures of 15, 20, 25, 30 °C while summer samples were incubated at 15, 25, 30, 33 °C, representing the maximum range the cells might experience throughout the water column due to daytime surface heating or extreme weather events. Depending on thermal history of the cells, photosynthetic performance differed when cells were exposed to the same temperature, showing a capacity for thermal acclimation in this species. Although blooms generally do not persist throughout the summer, bloom biomass was remarkably higher in summer than during the winter. However, most of the photosynthetic parameters and N uptake rates, as well as total carbon (C) and N cell-1 were significantly lower in the summer populations, showing that the summer populations were photosynthetically and nutritionally stressed. When the summer cells were treated with urea, however, uptake rates and total C and N cell-1 were higher than with the other N substrates, especially in warmer waters, showing differential thermal responses depending on N forms.
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Affiliation(s)
- So Hyun Ahn
- Horn Point Laboratory, University of Maryland Center for Environmental Science, 2020 Horns Point Road, Cambridge, MD 21613, United States.
| | - Patricia M Glibert
- Horn Point Laboratory, University of Maryland Center for Environmental Science, 2020 Horns Point Road, Cambridge, MD 21613, United States
| | - Cynthia A Heil
- Mote Marine Laboratory, 1600 Ken Thompson Pkwy, Sarasota, FL 34236, United States
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6
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Roussel A, Mériot V, Jauffrais T, Berteaux-Lecellier V, Lebouvier N. OMICS Approaches to Assess Dinoflagellate Responses to Chemical Stressors. BIOLOGY 2023; 12:1234. [PMID: 37759633 PMCID: PMC10525455 DOI: 10.3390/biology12091234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/13/2023] [Accepted: 07/18/2023] [Indexed: 09/29/2023]
Abstract
Dinoflagellates are important primary producers known to form Harmful Algae Blooms (HABs). In water, nutrient availability, pH, salinity and anthropogenic contamination constitute chemical stressors for them. The emergence of OMICs approaches propelled our understanding of dinoflagellates' responses to stressors. However, in dinoflagellates, these approaches are still biased, as transcriptomic approaches are largely conducted compared to proteomic and metabolomic approaches. Furthermore, integrated OMICs approaches are just emerging. Here, we report recent contributions of the different OMICs approaches to the investigation of dinoflagellates' responses to chemical stressors and discuss the current challenges we need to face to push studies further despite the lack of genomic resources available for dinoflagellates.
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Affiliation(s)
- Alice Roussel
- ISEA, EA7484, Campus de Nouville, Université de la Nouvelle Calédonie, Noumea 98851, New Caledonia; (A.R.); (V.M.)
| | - Vincent Mériot
- ISEA, EA7484, Campus de Nouville, Université de la Nouvelle Calédonie, Noumea 98851, New Caledonia; (A.R.); (V.M.)
- Ifremer, IRD, CNRS, Univ. de la Réunion, Univ. de la Nouvelle Calédonie, UMR 9220 ENTROPIE, 101 Promenade Roger Laroque, Noumea 98897, New Caledonia;
| | - Thierry Jauffrais
- Ifremer, IRD, CNRS, Univ. de la Réunion, Univ. de la Nouvelle Calédonie, UMR 9220 ENTROPIE, 101 Promenade Roger Laroque, Noumea 98897, New Caledonia;
| | - Véronique Berteaux-Lecellier
- CNRS, Ifremer, IRD, Univ. de la Réunion, Univ. de la Nouvelle Calédonie, UMR 9220 ENTROPIE, 101 Promenade Roger Laroque, Noumea 98897, New Caledonia;
| | - Nicolas Lebouvier
- ISEA, EA7484, Campus de Nouville, Université de la Nouvelle Calédonie, Noumea 98851, New Caledonia; (A.R.); (V.M.)
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7
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Saldivia P, Hernández M, Isla A, Fritz R, Varela D, González-Jartín JM, Figueroa J, Botana LM, Vargas C, Yañez AJ. Proteomic and toxicological analysis of the response of dinoflagellate Alexandrium catenella to changes in NaNO 3 concentration. HARMFUL ALGAE 2023; 125:102428. [PMID: 37220981 DOI: 10.1016/j.hal.2023.102428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 03/05/2023] [Accepted: 03/18/2023] [Indexed: 05/25/2023]
Abstract
Dinoflagellates of the genus Alexandrium cause Harmful Algal Blooms (HABs) in coastal waters worldwide, damaging marine environments, aquaculture, and human health. They synthesize potent neurotoxic alkaloids known as PSTs (i.e., Paralytic Shellfish Toxins), the etiological agents of PSP (i.e., Paralytic Shellfish Poisoning). In recent decades, the eutrophication of coastal waters with inorganic nitrogen (e.g., nitrate, nitrite, and ammonia) has increased the frequency and scale of HABs. PSTs concentrations within Alexandrium cells can increase by up to 76% after a nitrogen enrichment event; however, the mechanisms that underlie their biosynthesis in dinoflagellates remains unclear. This study combines mass spectrometry, bioinformatics, and toxicology and investigates the expression profiles of PSTs in Alexandrium catenella grown in 0.4, 0.9 and 1.3 mM NaNO3. Pathway analysis of protein expression revealed that tRNA amino acylation, glycolysis, TCA cycle and pigment biosynthesis were upregulated in 0.4 mM and downregulated in 1.3 mM NaNO3 compared to those grown in 0.9 mM NaNO3. Conversely, ATP synthesis, photosynthesis and arginine biosynthesis were downregulated in 0.4 mM and upregulated in 1.3 mM NaNO3. Additionally, the expression of proteins involved in PST biosynthesis (sxtA, sxtG, sxtV, sxtW and sxtZ) and overall PST production like STX, NEO, C1, C2, GTX1-6 and dcGTX2 was higher at lower nitrate concentrations. Therefore, increased nitrogen concentrations increase protein synthesis, photosynthesis, and energy metabolism and decrease enzyme expression in PST biosynthesis and production. This research provides new clues about how the changes in the nitrate concentration can modulate different metabolic pathways and the expression of PST biosynthesis in toxigenic dinoflagellates.
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Affiliation(s)
- Pablo Saldivia
- Division of Biotechnology, MELISA Institute, Concepción, Chile; Programa de Doctorado en Biotecnología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | | | - Adolfo Isla
- Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad Santo Tomás, Valdivia, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile; Laboratorio de Diagnóstico y Terapia, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Rocío Fritz
- Vicerrectoría de Investigación y Postgrado, Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Daniel Varela
- Centro i∼mar, Universidad de Los Lagos, Puerto Montt, Chile
| | - Jesús M González-Jartín
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, Lugo, Spain
| | - Jaime Figueroa
- Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile; Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Luis M Botana
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, Lugo, Spain
| | - Cristian Vargas
- Division of Biotechnology, MELISA Institute, Concepción, Chile
| | - Alejandro J Yañez
- Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile; Laboratorio de Diagnóstico y Terapia, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
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8
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Hano T, Tomaru Y. Chronological age-related metabolome responses in the dinoflagellate Karenia mikimotoi, can predict future bloom demise. Commun Biol 2023; 6:273. [PMID: 36922623 PMCID: PMC10017670 DOI: 10.1038/s42003-023-04646-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 03/01/2023] [Indexed: 03/18/2023] Open
Abstract
Karenia mikimotoi is a common harmful algal bloom (HAB)-forming dinoflagellate and has caused severe financial loss in aquaculture. There are limited metabolomic studies on dinoflagellate biology. Here, we examined alterations in metabolic profiles over the growth curve of K. mikimotoi under nitrogen or phosphorus deficiency and further explored a key criterion for the diagnosis of late stationary phase to identify when the dinoflagellate cells will enter bloom demise. The results demonstrate the differential expression of metabolites for coping with chronological aging or nutrient deprivation. Furthermore, an increase in the glucose to glycine ratio in the late stationary phase was indicative of dinoflagellate cells entering bloom demise; this was also detected in the cultured diatom, Chaetoceros tenuissimus, indicating that this may be the general criterion for phytoplankton species. Our findings provide insights regarding chronological aging and the criterion for the prediction of phytoplankton bloom demise.
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Affiliation(s)
- Takeshi Hano
- Environment Conservation Division, Fisheries Technology Institute, National Research and Development Agency, Japan Fisheries Research and Education Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima, 739-0452, Japan.
| | - Yuji Tomaru
- Environment Conservation Division, Fisheries Technology Institute, National Research and Development Agency, Japan Fisheries Research and Education Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima, 739-0452, Japan
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9
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Full-Length Transcriptome Analysis of the Ichthyotoxic Harmful Alga Heterosigma akashiwo (Raphidophyceae) Using Single-Molecule Real-Time Sequencing. Microorganisms 2023; 11:microorganisms11020389. [PMID: 36838354 PMCID: PMC9959365 DOI: 10.3390/microorganisms11020389] [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: 11/20/2022] [Revised: 01/25/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023] Open
Abstract
The raphidophyte Heterosigma akashiwo is a harmful algal species. The bloom of this organism has been associated with the massive mortality of fish in many coastal waters. To investigate the molecular mechanism of H. akashiwo blooms, having a reliable reference transcriptome of this species is essential. Therefore, in this study, a full-length transcriptome of H. akashiwo was obtained by single-molecule real-time sequencing. In total, 45.44 Gb subread bases were generated, and 16,668 unigenes were obtained after the sequencing data processing. A total of 8666 (52.00%) unigenes were successfully annotated using seven public databases. Among them, mostly phosphorus and nitrogen metabolism genes were detected. Moreover, there were 300 putative transcription factors, 4392 putative long non-coding RNAs, and 7851 simple sequence repeats predicted. This study provides a valuable reference transcriptome for understanding how H. akashiwo blooms at a molecular level.
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Cho Y, Tsuchiya S, Omura T, Koike K, Konoki K, Oshima Y, Yotsu-Yamashita M. Metabolic inhibitor induces dynamic changes in saxitoxin biosynthesis and metabolism in the dinoflagellate Alexandrium pacificum (Group IV) under in vivo labeling condition. HARMFUL ALGAE 2023; 122:102372. [PMID: 36754461 DOI: 10.1016/j.hal.2022.102372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 12/14/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
In paralytic shellfish toxin-producing dinoflagellates, intracellular levels of saxitoxin and its analogues (STXs) are controlled by a balance between degradation and biosynthesis in response to marine environmental fluctuations and stresses. The purpose of this study was to demonstrate the utility of statistical analysis of in vivo labeling data for the dynamic analysis of variations in toxin production under stress. A toxic strain of the dinoflagellate Alexandrium pacificum (Group IV) was cultured in colchicine-containing 15N-labeled sodium nitrate-medium and metabolite levels were analyzed over time by liquid chromatography-mass spectrometry. Quantitative values of all isotopomers of precursor amino acids, biosynthetic intermediates, and major STXs were subjected to statistical analysis. The decrease of the nitrogen incorporation rates for all compounds suggested that colchicine decreased nitrate assimilation upstream of glutamate biosynthesis. In colchicine-treated cultures, the per-cell content of total STX analogues did not change significantly over time; however, the production rate of each pathway varied greatly. De novo STX biosynthesis was decreased by colchicine until Day 3, while the salvage pathway was not. Subsequently, biosynthesis by both pathways was enhanced. This analysis of dynamic metabolism provides new insights into the complex mechanisms regulating STX metabolism in dinoflagellates.
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Affiliation(s)
- Yuko Cho
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan.
| | - Shigeki Tsuchiya
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Takuo Omura
- Laboratory of Aquatic Science Consultant Co., LTD. 2-30-17, Higashikamata, Ota-ku, Tokyo 144-0031, Japan
| | - Kazuhiko Koike
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
| | - Keiichi Konoki
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Yasukatsu Oshima
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
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11
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Kamalanathan M, Mapes S, Prouse A, Faulkner P, Klobusnik NH, Hillhouse J, Hala D, Quigg A. Core metabolism plasticity in phytoplankton: Response of Dunaliella tertiolecta to oil exposure. JOURNAL OF PHYCOLOGY 2022; 58:804-814. [PMID: 36056600 PMCID: PMC10087180 DOI: 10.1111/jpy.13286] [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: 06/06/2022] [Accepted: 08/23/2022] [Indexed: 06/15/2023]
Abstract
Human alterations to the marine environment such as an oil spill can induce oxidative stress in phytoplankton. Exposure to oil has been shown to be lethal to most phytoplankton species, but some are able to survive and grow at unaffected or reduced growth rates, which appears to be independent of the class and phylum of the phytoplankton and their ability to consume components of oil heterotrophically. The goal of this article is to test the role of core metabolism plasticity in the oil-resisting ability of phytoplankton. Experiments were performed on the oil- resistant chlorophyte, Dunaliella tertiolecta, in control and water accommodated fractions of oil, with and without metabolic inhibitors targeting the core metabolic pathways. We observed that inhibiting pathways such as photosynthetic electron transport (PET) and pentose-phosphate pathway were lethal; however, inhibition of pathways such as mitochondrial electron transport and cyclic electron transport caused growth to be arrested. Pathways such as photorespiration and Kreb's cycle appear to play a critical role in the oil-tolerating ability of D. tertiolecta. Analysis of photo-physiology revealed reduced PET under inhibition of photorespiration but not Kreb's cycle. Further studies showed enhanced flux through Kreb's cycle suggesting increased energy production and photorespiration counteract oxidative stress. Lastly, reduced extracellular carbohydrate secretion under oil exposure indicated carbon and energy conservation, which together with enhanced flux through Kreb's cycle played a major role in the survival of D. tertiolecta under oil exposure by meeting the additional energy demands. Overall, we present data that suggest the role of phenotypic plasticity of multiple core metabolic pathways in accounting for the oxidative stress tolerating ability of certain phytoplankton species.
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Affiliation(s)
- Manoj Kamalanathan
- Department of Marine BiologyTexas A&M University at GalvestonGalvestonTexas77573USA
- Present address:
Bigelow Laboratory for Ocean SciencesEast BoothbayMaine04544USA
| | - Savannah Mapes
- Department of Marine BiologyTexas A&M University at GalvestonGalvestonTexas77573USA
- Present address:
Virginia Institute of Marine ScienceGloucester PointVirginia23062USA
| | - Alexandra Prouse
- Department of Marine BiologyTexas A&M University at GalvestonGalvestonTexas77573USA
| | - Patricia Faulkner
- Department of Marine BiologyTexas A&M University at GalvestonGalvestonTexas77573USA
| | | | - Jessica Hillhouse
- Department of Marine BiologyTexas A&M University at GalvestonGalvestonTexas77573USA
| | - David Hala
- Department of Marine BiologyTexas A&M University at GalvestonGalvestonTexas77573USA
| | - Antonietta Quigg
- Department of Marine BiologyTexas A&M University at GalvestonGalvestonTexas77573USA
- Department of OceanographyTexas A&M UniversityCollege StationTexas77845USA
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A Novel Algicidal Bacterium and Its Effects against the Toxic Dinoflagellate Karenia mikimotoi (Dinophyceae). Microbiol Spectr 2022; 10:e0042922. [PMID: 35616372 PMCID: PMC9241683 DOI: 10.1128/spectrum.00429-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The toxic dinoflagellate Karenia mikimotoi is a harmful algal bloom-forming species in coastal areas around the world. It produces ichthyotoxins and hemolytic toxins, with deleterious effects on marine ecosystems. In this study, the bacterium Pseudoalteromonas sp. FDHY-MZ2, with high algicidal efficiency against K. mikimotoi, was isolated from a bloom event. Based on the results, it completely lysed K. mikimotoi cells within 24 h 0.5% (vol/vol), with the algicidal activity of the supernatant of the bacterium culture. Algal cell wall fragmentation occurred, leading to cell death. There was a marked decline in various photochemical traits. When treated with the supernatant, cellulase, pheophorbide a oxygenase (PAO) and cyclin B genes were significantly increased, suggesting induced cell wall deterioration, chloroplast degradation and cell cycle regulation of K. mikimotoi cells. In addition, the expression levels of reactive oxygen species (ROS) scavenging gene was significantly inhibited, indicating that the ROS removal system was damaged. The bacterial culture was dried to obtain the spray-dried powder, which showed algicidal activity rates of 92.2 and 100% against a laboratory K. mikimotoi culture and a field microcosm of Karlodinium sp. bloom within 24 h with the addition of 0.04% mass fraction powder. Our results demonstrate that FDHY-MZ2 is a suitable strain for K. mikimotoi and Karlodinium sp. blooms management. In addition, this study provides a new strategy for the anthropogenic control of harmful algal bloom-forming species in situ. IMPORTANCE K. mikimotoi is a noxious algal bloom-forming species that cause damaging of the aquaculture industry and great financial losses. Bacterium with algicidal activity is an ideal agency to inhibit the growth of harmful algae. In this approach application, the bacterium with high algicidal activity is required and the final management material is ideal for easy-to-use. The algicidal characteristics are also needed to understand the effects of the bacterium for managing strategy exploration. In this study, we isolated a novel algicidal bacterium with extremely high lysis efficiency for K. mikimotoi. The algicidal characteristics of the bacterium as well as the chemical and molecular response of K. mikimotoi with the strain challenge were examined. Finally, the algicidal powder was explored for application. The results demonstrate that FDHY-MZ2 is suitable for K. mikimotoi and Karlodinium sp. blooms controlling, and this study provides a new strategy for algicidal bacterium application.
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Gann ER, Truchon AR, Papoulis SE, Dyhrman ST, Gobler CJ, Wilhelm SW. Aureococcus anophagefferens (Pelagophyceae) genomes improve evaluation of nutrient acquisition strategies involved in brown tide dynamics. JOURNAL OF PHYCOLOGY 2022; 58:146-160. [PMID: 34773248 DOI: 10.1111/jpy.13221] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 06/13/2023]
Abstract
The pelagophyte Aureococcus anophagefferens causes harmful brown tide blooms in marine embayments on three continents. Aureococcus anophagefferens was the first harmful algal bloom species to have its genome sequenced, an advance that evidenced genes important for adaptation to environmental conditions that prevail during brown tides. To expand the genomic tools available for this species, genomes for four strains were assembled, including three newly sequenced strains and one assembled from publicly available data. These genomes ranged from 57.11 to 73.62 Mb, encoding 13,191-17,404 potential proteins. All strains shared ~90% of their encoded proteins as determined by homology searches and shared most functional orthologs as determined by KEGG, although each strain also possessed coding sequences with unique functions. Like the original reference genome, the genomes assembled in this study possessed genes hypothesized to be important in bloom proliferation, including genes involved in organic compound metabolism and growth at low light. Cross-strain informatics and culture experiments suggest that the utilization of purines is a potentially important source of organic nitrogen for brown tides. Analyses of metatranscriptomes from a brown tide event demonstrated that use of a single genome yielded a lower read mapping percentage (~30% of library reads) as compared to a database generated from all available genomes (~43%), suggesting novel information about bloom ecology can be gained from expanding genomic space. This work demonstrates the continued need to sequence ecologically relevant algae to understand the genomic potential and their ecology in the environment.
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Affiliation(s)
- Eric R Gann
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Alexander R Truchon
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Spiridon E Papoulis
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Sonya T Dyhrman
- Biology and Paleo Environment Division, Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, 10964, USA
- Department of Earth and Environmental Sciences, Columbia University, Palisades, New York, 10964, USA
| | - Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, 11790, USA
| | - Steven W Wilhelm
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, 37996, USA
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