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Zhu H, Ye Z, Xu Z, Wei L. Transcriptomic Analysis Reveals the Effect of Urea on Metabolism of Nannochloropsis oceanica. Life (Basel) 2024; 14:797. [PMID: 39063552 PMCID: PMC11278182 DOI: 10.3390/life14070797] [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: 04/10/2024] [Revised: 06/20/2024] [Accepted: 06/21/2024] [Indexed: 07/28/2024] Open
Abstract
The eukaryotic microalga Nannochloropsis oceanica represents a promising bioresource for the production of biofuels and pharmaceuticals. Urea, a crucial nutrient for the photosynthetic N. oceanica, stimulates the accumulation of substances such as lipids, which influence growth and physiology. However, the specific mechanisms by which N. oceanica responds and adapts to urea addition remain unknown. High-throughput mRNA sequencing and differential gene expression analysis under control and urea-added conditions revealed significant metabolic changes. This involved the differential expression of 2104 genes, with 1354 being upregulated and 750 downregulated, resulting in the reprogramming of crucial pathways such as carbon and nitrogen metabolism, photosynthesis, and lipid metabolism. The results specifically showed that genes associated with photosynthesis in N. oceanica were significantly downregulated, particularly those related to light-harvesting proteins. Interestingly, urea absorption and transport may depend not only on specialized transport channels such as urease but also on alternative transport channels such as the ABC transporter family and the CLC protein family. In addition, urea caused specific changes in carbon and lipid metabolism. Genes associated with the Calvin cycle and carbon concentration mechanisms were significantly upregulated. In lipid metabolism, the expression of genes associated with lipases and polyunsaturated fatty acid synthesis was highly activated. Furthermore, the expression of several genes involved in the tricarboxylic acid cycle and folate metabolism was enhanced, making important contributions to energy supply and the synthesis and modification of genes and macromolecules. Our observations indicate that N. oceanica actively and dynamically regulates the redistribution of carbon and nitrogen after urea addition, providing references for further research on the effects of urea on N. oceanica.
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Affiliation(s)
- Han Zhu
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou 571158, China
- Hainan Observation and Research Station of Dongzhaigang Mangrove Wetland Ecosystem, Haikou 571129, China
- International Science and Technology Cooperation Laboratory for Marine Microalgae Ecological Carbon Sinks, Hainan Normal University, Haikou 571158, China
| | - Zhenli Ye
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou 571158, China
| | - Zhengru Xu
- College of Foreign Language, Hainan Normal University, Haikou 571157, China
| | - Li Wei
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou 571158, China
- Hainan Observation and Research Station of Dongzhaigang Mangrove Wetland Ecosystem, Haikou 571129, China
- International Science and Technology Cooperation Laboratory for Marine Microalgae Ecological Carbon Sinks, Hainan Normal University, Haikou 571158, China
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Kalinina V, Berdieva M, Aksenov N, Skarlato S. Phosphorus deficiency induces sexual reproduction in the dinoflagellate Prorocentrum cordatum. Sci Rep 2023; 13:14191. [PMID: 37648777 PMCID: PMC10468533 DOI: 10.1038/s41598-023-41339-3] [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: 06/16/2023] [Accepted: 08/24/2023] [Indexed: 09/01/2023] Open
Abstract
Nitrogen (N) and phosphorus (P) are essential elements whose availability promotes successful growth of phytoplankton and governs aquatic primary productivity. In this study, we investigated the effect of N and/or P deficiency on the sexual reproduction of Prorocentrum cordatum, the dinoflagellate with the haplontic life cycle which causes harmful algal blooms worldwide. In P. cordatum cultures, N and the combined N and P deficiency led to the arrest of the cell cycle in the G0/G1 phases and attenuation of cell culture growth. We observed, that P, but not N deficiency triggered the transition in the life cycle of P. cordatum from vegetative to the sexual stage. This resulted in a sharp increase in percentage of cells with relative nuclear DNA content 2C (zygotes) and the appearance of cells with relative nuclear DNA content 4C (dividing zygotes). Subsequent supplementation with phosphate stimulated meiosis and led to a noticeable increase in the 4C cell number (dividing zygotes). Additionally, we performed transcriptomic data analysis and identified putative phosphate transporters and enzymes involved in the phosphate uptake and regulation of its metabolism by P. cordatum. These include high- and low-affinity inorganic phosphate transporters, atypical alkaline phosphatase, purple acid phosphatases and SPX domain-containing proteins.
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Affiliation(s)
- Vera Kalinina
- Laboratory of Cytology of Unicellular Organisms, Institute of Cytology of the Russian Academy of Sciences, St.-Petersburg, 194064, Russia.
| | - Mariia Berdieva
- Laboratory of Cytology of Unicellular Organisms, Institute of Cytology of the Russian Academy of Sciences, St.-Petersburg, 194064, Russia
| | - Nikolay Aksenov
- Laboratory of Intracellular Membrane Dynamics, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg, 194064, Russia
| | - Sergei Skarlato
- Laboratory of Cytology of Unicellular Organisms, Institute of Cytology of the Russian Academy of Sciences, St.-Petersburg, 194064, Russia
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Wang C, Zhu WJ, Ding HT, Liu NH, Cao HY, Suo CL, Liu ZK, Zhang Y, Sun ML, Fu HH, Li CY, Chen XL, Zhang YZ, Wang P. Structural and molecular basis for urea recognition by Prochlorococcus. J Biol Chem 2023; 299:104958. [PMID: 37380083 PMCID: PMC10392092 DOI: 10.1016/j.jbc.2023.104958] [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: 02/16/2023] [Revised: 06/09/2023] [Accepted: 06/21/2023] [Indexed: 06/30/2023] Open
Abstract
Nitrogen (N) is an essential element for microbial growth and metabolism. The growth and reproduction of microorganisms in more than 75% of areas of the ocean are limited by N. Prochlorococcus is numerically the most abundant photosynthetic organism on the planet. Urea is an important and efficient N source for Prochlorococcus. However, how Prochlorococcus recognizes and absorbs urea still remains unclear. Prochlorococcus marinus MIT 9313, a typical Cyanobacteria, contains an ABC-type transporter, UrtABCDE, which may account for the transport of urea. Here, we heterologously expressed and purified UrtA, the substrate-binding protein of UrtABCDE, detected its binding affinity toward urea, and further determined the crystal structure of the UrtA/urea complex. Molecular dynamics simulations indicated that UrtA can alternate between "open" and "closed" states for urea binding. Based on structural and biochemical analyses, the molecular mechanism for urea recognition and binding was proposed. When a urea molecule is bound, UrtA undergoes a state change from open to closed surrounding the urea molecule, and the urea molecule is further stabilized by the hydrogen bonds supported by the conserved residues around it. Moreover, bioinformatics analysis showed that ABC-type urea transporters are widespread in bacteria and probably share similar urea recognition and binding mechanisms as UrtA from P. marinus MIT 9313. Our study provides a better understanding of urea absorption and utilization in marine bacteria.
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Affiliation(s)
- Chen Wang
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, China; State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Wen-Jing Zhu
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, China; State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Hai-Tao Ding
- Antarctic Great Wall Ecology National Observation and Research Station, Polar Research Institute of China, Shanghai, China
| | - Ning-Hua Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Hai-Yan Cao
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Chuan-Lei Suo
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Ze-Kun Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Yi Zhang
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Mei-Ling Sun
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Hui-Hui Fu
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Chun-Yang Li
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China; Marine Biotechnology Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Yu-Zhong Zhang
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China; Marine Biotechnology Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Peng Wang
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.
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Abassi S, Ki JS. Increased nitrate concentration differentially affects cell growth and expression of nitrate transporter and other nitrogen-related genes in the harmful dinoflagellate Prorocentrum minimum. CHEMOSPHERE 2022; 288:132526. [PMID: 34637868 DOI: 10.1016/j.chemosphere.2021.132526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/29/2021] [Accepted: 10/08/2021] [Indexed: 06/13/2023]
Abstract
The molecular mechanisms through which dinoflagellates adapt to nitrate fluctuations in aquatic environments remain poorly understood. Here, we sequenced the full-length cDNA of a nitrate transporter (NRT) gene from the harmful marine dinoflagellate Prorocentrum minimum Schiller. The cDNA length was 2431 bp. It encoded a 529-amino acid protein, which was phylogenetically clustered with proteins from other dinoflagellates. Nitrate supply promoted cell growth up to a certain concentration (∼1.76 mM) but inhibited it at higher concentrations. Interestingly, at the inhibitory concentrations, nitrite levels in the medium were considerably increased. Nitrate concentration affected the expression of PmNRT, nitrite transporter (PmNiRT), nitrate reductase (PmNR), and nitrite reductase (PmNiR). Specifically, PmNRT was upregulated after 24 h, with ∼6-fold change compared with the control level, in both nitrate-depleted and nitrate-repleted cultures. In addition, PmNR transcript levels increased to the maximum of 4-fold at 48 h but decreased thereafter. In contrast, PmNiR levels remained unchanged in both nitrate-repleted and nitrate-depleted cultures. Therefore, P. minimum likely copes with nitrate fluctuations in its environment by regulating a set of genes responsible for nitrate uptake.
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Affiliation(s)
- Sofia Abassi
- Department of Biotechnology, Sangmyung University, Seoul, 03016, South Korea
| | - Jang-Seu Ki
- Department of Biotechnology, Sangmyung University, Seoul, 03016, South Korea.
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Insights into Alexandrium minutum Nutrient Acquisition, Metabolism and Saxitoxin Biosynthesis through Comprehensive Transcriptome Survey. BIOLOGY 2021; 10:biology10090826. [PMID: 34571703 PMCID: PMC8465370 DOI: 10.3390/biology10090826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/12/2021] [Accepted: 08/13/2021] [Indexed: 11/17/2022]
Abstract
Simple Summary Alexandrium minutum is one of the causing organisms for the occurrence of harmful algae bloom (HABs) in marine ecosystems. This species produces saxitoxin, one of the deadliest neurotoxins which can cause human mortality. However, molecular information such as genes and proteins catalog on this species is still lacking. Therefore, this study has successfully characterized several new molecular mechanisms regarding A. minutum environmental adaptation and saxitoxin biosynthesis. Ultimately, this study provides a valuable resource for facilitating future dinoflagellates’ molecular response to environmental changes. Abstract The toxin-producing dinoflagellate Alexandrium minutum is responsible for the outbreaks of harmful algae bloom (HABs). It is a widely distributed species and is responsible for producing paralytic shellfish poisoning toxins. However, the information associated with the environmental adaptation pathway and toxin biosynthesis in this species is still lacking. Therefore, this study focuses on the functional characterization of A. minutum unigenes obtained from transcriptome sequencing using the Illumina Hiseq 4000 sequencing platform. A total of 58,802 (47.05%) unigenes were successfully annotated using public databases such as NCBI-Nr, UniprotKB, EggNOG, KEGG, InterPRO and Gene Ontology (GO). This study has successfully identified key features that enable A. minutum to adapt to the marine environment, including several carbon metabolic pathways, assimilation of various sources of nitrogen and phosphorus. A. minutum was found to encode homologues for several proteins involved in saxitoxin biosynthesis, including the first three proteins in the pathway of saxitoxin biosynthesis, namely sxtA, sxtG and sxtB. The comprehensive transcriptome analysis presented in this study represents a valuable resource for understanding the dinoflagellates molecular metabolic model regarding nutrient acquisition and biosynthesis of saxitoxin.
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