1
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Bui QTN, Ki JS. Two novel superoxide dismutase genes (CuZnSOD and MnSOD) in the toxic marine dinoflagellate Alexandrium pacificum and their differential responses to metal stressors. Chemosphere 2023; 313:137532. [PMID: 36509186 DOI: 10.1016/j.chemosphere.2022.137532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Superoxide dismutase (SOD) is an important antioxidant enzyme that is involved in the first line of defense against reactive oxygen species (ROS) within cells. Herein, we determined two novel CuZnSOD and MnSOD genes from the toxic marine dinoflagellate Alexandrium pacificum (designated as ApCuZnSOD and ApMnSOD) and characterized their structural features and phylogenetic affiliations. In addition, we examined the relative gene expression and ROS levels following exposure to heavy metals. ApCuZnSOD encoded 358 amino acids (aa) with two CuZnSOD-conserved domains. ApMnSOD encoded 203 aa that contained a mitochondrial-targeting signal and a MnSOD signature motif but missed an N-terminal domain. Phylogenetic trees showed that ApCuZnSOD clustered with other dinoflagellates, whereas ApMnSOD formed a clade with green algae and plants. Based on the 72-h median effective concentration (EC50), A. pacificum showed toxic responses in the order of Cu, Ni, Cr, Zn, Cd, and Pb. SOD expression levels dramatically increased after 6 h of Pb (≥6.5 times) and 48 h of Cu treatment (≥3.9 times). These results are consistent with the significant increase in ROS production in the A. pacificum exposed to Pb and Cu. These suggest that the two ApSODs are involved in the antioxidant defense system but respond differentially to individual metals.
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Affiliation(s)
- Quynh Thi Nhu Bui
- 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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2
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Nowicka B. Heavy metal-induced stress in eukaryotic algae-mechanisms of heavy metal toxicity and tolerance with particular emphasis on oxidative stress in exposed cells and the role of antioxidant response. Environ Sci Pollut Res Int 2022; 29:16860-16911. [PMID: 35006558 PMCID: PMC8873139 DOI: 10.1007/s11356-021-18419-w] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/27/2021] [Indexed: 04/15/2023]
Abstract
Heavy metals is a collective term describing metals and metalloids with a density higher than 5 g/cm3. Some of them are essential micronutrients; others do not play a positive role in living organisms. Increased anthropogenic emissions of heavy metal ions pose a serious threat to water and land ecosystems. The mechanism of heavy metal toxicity predominantly depends on (1) their high affinity to thiol groups, (2) spatial similarity to biochemical functional groups, (3) competition with essential metal cations, (4) and induction of oxidative stress. The antioxidant response is therefore crucial for providing tolerance to heavy metal-induced stress. This review aims to summarize the knowledge of heavy metal toxicity, oxidative stress and antioxidant response in eukaryotic algae. Types of ROS, their formation sites in photosynthetic cells, and the damage they cause to the cellular components are described at the beginning. Furthermore, heavy metals are characterized in more detail, including their chemical properties, roles they play in living cells, sources of contamination, biochemical mechanisms of toxicity, and stress symptoms. The following subchapters contain the description of low-molecular-weight antioxidants and ROS-detoxifying enzymes, their properties, cellular localization, and the occurrence in algae belonging to different clades, as well as the summary of the results of the experiments concerning antioxidant response in heavy metal-treated eukaryotic algae. Other mechanisms providing tolerance to metal ions are briefly outlined at the end.
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Affiliation(s)
- Beatrycze Nowicka
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland.
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3
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Gong Y, Zhang K, Geng N, Wu M, Yi X, Liu R, Challis JK, Codling G, Xu EG, Giesy JP. Molecular mechanisms of zooplanktonic toxicity in the okadaic acid-producing dinoflagellate Prorocentrum lima. Environ Pollut 2021; 279:116942. [PMID: 33765503 DOI: 10.1016/j.envpol.2021.116942] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 03/01/2021] [Accepted: 03/02/2021] [Indexed: 06/12/2023]
Abstract
Prorocentrum lima is a dinoflagellate that forms hazardous blooms and produces okadaic acid (OA), leading to adverse environmental consequences associated with the declines of zooplankton populations. However, little is known about the toxic effects and molecular mechanisms of P. lima or OA on zooplankton. Here, their toxic effects were investigated using the brine shrimp Artemia salina. Acute exposure of A. salina to P. lima resulted in lethality at concentrations 100-fold lower than densities observed during blooms. The first comprehensive results from global transcriptomic and metabolomic analyses in A. salina showed up-regulated mRNA expression of antioxidant enzymes and reduced non-enzyme antioxidants, indicating general detoxification responses to oxidative stress after exposure to P. lima. The significantly up-regulated mRNA expression of proteasome, spliceosome, and ribosome, as well as the increased fatty acid oxidation and oxidative phosphorylation suggested the proteolysis of damaged proteins and induction of energy expenditure. Exposure to OA increased catabolism of chitin, which may further disrupt the molting and reproduction activities of A. salina. Our data shed new insights on the molecular responses and toxicity mechanisms of A. salina to P. lima or OA. The simple zooplankton model integrated with omic methods provides a sensitive assessment approach for studying hazardous algae.
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Affiliation(s)
- Yufeng Gong
- School of Ocean Science and Technology, Dalian University of Technology, Panjin Campus, Panjin, Liaoning, China; Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada
| | - Keke Zhang
- School of Ocean Science and Technology, Dalian University of Technology, Panjin Campus, Panjin, Liaoning, China
| | - Ningbo Geng
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Minghuo Wu
- School of Ocean Science and Technology, Dalian University of Technology, Panjin Campus, Panjin, Liaoning, China
| | - Xianliang Yi
- School of Ocean Science and Technology, Dalian University of Technology, Panjin Campus, Panjin, Liaoning, China.
| | - Renyan Liu
- National Marine Environmental Monitoring Center, Dalian, Liaoning, China
| | | | - Garry Codling
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada; RECETOX Centre, Masaryk University, Kamenice, Brno, Czech Republic
| | - Elvis Genbo Xu
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | - John P Giesy
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada; Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK, Canada; Department of Environmental Sciences, Baylor University, Waco, TX, USA; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, People's Republic of China
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Kim H, Wang H, Ki JS. Chloroacetanilides inhibit photosynthesis and disrupt the thylakoid membranes of the dinoflagellate Prorocentrum minimum as revealed with metazachlor treatment. Ecotoxicol Environ Saf 2021; 211:111928. [PMID: 33476845 DOI: 10.1016/j.ecoenv.2021.111928] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 06/12/2023]
Abstract
The chloroacetanilides are among the most commonly used herbicides worldwide, which contaminate aquatic environments and affect aquatic phototrophs. Their sub-lethal toxicity has been evaluated using freshwater algae; however, the modes of cellular toxicity and levels of toxicity to marine organisms are not fully understood. In the present study, we assessed the cellular and molecular effects of chloroacetanilides on marine phototrophs using the dinoflagellate Prorocentrum minimum and the herbicide metazachlor (MZC). The MZC treatment led to a considerable reduction in cell number and pigment, and the EC50 of MZC was calculated to be 0.647 mg/L. The photosynthetic parameters, Fv/Fm and chlorophyll fluorescence significantly decreased with MZC exposure time in a dose-dependent manner. In addition, MZC significantly induced photosynthesis genes, including PmpsbA, PmpsaA, and PmatpB, and the antioxidant PmGST, but not PmKatG. These findings were well matched to reactive oxygen species (ROS) production in MZC-treated cells. Interestingly, we observed inflated vacuoles, undivided chloroplasts, and breakdown of thylakoid membranes in MZC-treated cells. These results support the hypothesis that MZC severely damages chloroplasts, resulting in dysfunction of the dinoflagellate photosynthesis and possibly marine phototrophs in the environment.
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Affiliation(s)
- Hansol Kim
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea
| | - Hui Wang
- 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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Vingiani GM, Štālberga D, De Luca P, Ianora A, De Luca D, Lauritano C. De novo Transcriptome of the Non-saxitoxin Producing Alexandrium tamutum Reveals New Insights on Harmful Dinoflagellates. Mar Drugs 2020; 18:E386. [PMID: 32722301 DOI: 10.3390/md18080386] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 12/17/2022] Open
Abstract
Many dinoflagellates species, especially of the Alexandrium genus, produce a series of toxins with tremendous impacts on human and environmental health, and tourism economies. Alexandrium tamutum was discovered for the first time in the Gulf of Naples, and it is not known to produce saxitoxins. However, a clone of A. tamutum from the same Gulf showed copepod reproduction impairment and antiproliferative activity. In this study, the full transcriptome of the dinoflagellate A. tamutum is presented in both control and phosphate starvation conditions. RNA-seq approach was used for in silico identification of transcripts that can be involved in the synthesis of toxic compounds. Phosphate starvation was selected because it is known to induce toxin production for other Alexandrium spp. Results showed the presence of three transcripts related to saxitoxin synthesis (sxtA, sxtG and sxtU), and others potentially related to the synthesis of additional toxic compounds (e.g., 44 transcripts annotated as "polyketide synthase"). These data suggest that even if this A. tamutum clone does not produce saxitoxins, it has the potential to produce toxic metabolites, in line with the previously observed activity. These data give new insights into toxic microalgae, toxin production and their potential applications for the treatment of human pathologies.
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Wang H, Ki JS. Molecular characterization and expression analysis of copper-zinc superoxide dismutases from the freshwater alga Closterium ehrenbergii under metal stress. Environ Toxicol 2020; 35:5-14. [PMID: 31452338 DOI: 10.1002/tox.22837] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 08/08/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Superoxide dismutase (SOD) acts as the first line of defense against reactive oxygen species (ROS) within cells. In the present study, we determined two novel CuZnSOD genes (designated as CeCSD1 and CeCSD2) from the toxicity-testing freshwater algae Closterium ehrenbergii and examined their structural features, phylogenetic relationships, and gene expression under exposure to different metals. Putative CeCSD1 (204 aa, 20.6 kDa) and CeCSD2 (155 aa, 15.3 kDa) proteins had conserved CuZnSOD family motifs and metal (Cu, Zn) binding sites, but different N-terminus structures, that is, CeCSD1 has a signal peptide to chloroplasts. Phylogenetic analysis of each protein revealed that C. ehrenbergii was well clustered with other green algae and plants. Real-time PCR results showed that the gene expression obviously increased with heavy metal exposure. In addition, excess copper considerably increased the SOD activity and ROS generation but decreased the photosynthetic efficiency in treated cells. These results suggest that CeCSDs are involved in the antioxidant defense system and can be regarded as potential biomarkers for monitoring metal contaminants in aquatic environments.
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Affiliation(s)
- Hui Wang
- 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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Wang H, Kim H, Lim WA, Ki JS. Molecular cloning and oxidative-stress responses of a novel manganese superoxide dismutase (MnSOD) gene in the dinoflagellate Prorocentrum minimum. Mol Biol Rep 2019; 46:5955-5966. [PMID: 31407247 DOI: 10.1007/s11033-019-05029-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 08/07/2019] [Indexed: 10/26/2022]
Abstract
Dinoflagellate algae are microeukaryotes that have distinct genomes and gene regulation systems, making them an interesting model for studying protist evolution and genomics. In the present study, we discovered a novel manganese superoxide dismutase (PmMnSOD) gene from the marine dinoflagellate Prorocentrum minimum, examined its molecular characteristics, and evaluated its transcriptional responses to the oxidative stress-inducing contaminants, CuSO4 and NaOCl. Its cDNA was 1238 bp and contained a dinoflagellate spliced leader sequence, a 906 bp open reading frame (301 amino acids), and a poly (A) tail. The gene was coded on the nuclear genome with one 174 bp intron; signal peptide analysis showed that it might be localized to the mitochondria. Real-time PCR analysis revealed an increase in gene expression of MnSOD and SOD activity when P. minimum cells were separately exposed to CuSO4 and NaOCl. In addition, both contaminants considerably decreased chlorophyll autofluorescence, and increased intracellular reactive oxygen species. These results suggest that dinoflagellate MnSOD may be involved in protecting cells against oxidative damage.
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Affiliation(s)
- Hui Wang
- Department of Biotechnology, Sangmyung University, Seoul, 03016, South Korea
| | - Hansol Kim
- Department of Biotechnology, Sangmyung University, Seoul, 03016, South Korea
| | - Weol-Ae Lim
- Ocean Climate and Ecology Research Division, National Institute of Fisheries Science (NIFS), Busan, 46083, South Korea
| | - Jang-Seu Ki
- Department of Biotechnology, Sangmyung University, Seoul, 03016, South Korea.
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Sathasivam R, Ki JS. Differential transcriptional responses of carotenoid biosynthesis genes in the marine green alga Tetraselmis suecica exposed to redox and non-redox active metals. Mol Biol Rep 2019; 46:1167-79. [PMID: 30649658 DOI: 10.1007/s11033-018-04583-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 12/20/2018] [Indexed: 10/27/2022]
Abstract
The green microalga, Tetraselmis suecica, is commonly used in scientific, industrial, and aquacultural purposes because of its high stress tolerance and ease of culture in wide spectrums of environments. We hypothesized that carotenoids help to protect Tetraselmis cells from environmental stress by regulating genes in biosynthetic pathways. Here, we determined three major carotenogenic genes, phytoene synthase (PSY), phytoene desaturase (PDS), and β-lycopene cyclase (LCY-B) in T. suecica, and examined the physiological parameters and gene expression responses when exposed to redox-active metals and non-redox-active metals. Phylogenetic analyses of each gene indicated that T. suecica clustered well with other green algae. Real-time PCR analysis showed that TsPSY, TsPDS, and TsLCY-B genes greatly responded to the redox-active metals in CuSO4 followed by CuCl2, but not to the non-redox-active metals. The redox-active metals strongly affected the physiology of the cells, as determined by cell counting, reactive oxygen species (ROS) imaging, and photosynthetic efficiency. This suggests that carotenoids protect the cells from oxidative damage caused by metals, thereby contributing to cell survival under various stress conditions.
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Wang H, Abassi S, Ki JS. Origin and roles of a novel copper-zinc superoxide dismutase (CuZnSOD) gene from the harmful dinoflagellate Prorocentrum minimum. Gene 2018; 683:113-122. [PMID: 30304703 DOI: 10.1016/j.gene.2018.10.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 09/11/2018] [Accepted: 10/06/2018] [Indexed: 10/28/2022]
Abstract
Superoxide dismutase (SOD) acts as the first line of defence against reactive oxygen species (ROS) within cells. In this study, we characterized a novel SOD gene (PmCuZnSOD) from the dinoflagellate Prorocentrum minimum, and examined its structural features, putative origin and gene expression. The SOD cDNA is 895 bp in length, containing dinoflagellate splice-leader (dinoSL) sequence, 714-bp ORF (237 aa), and poly (A) tail. In addition, PmCuZnSOD is coded on the dinoflagellate nuclear genome without introns and in a non-tandem repeat manner; however, the encoded protein is probably localized in chloroplasts. Phylogenetic analysis indicated that it might be acquired from cyanobacteria via horizontal gene transfer (HGT) and then the gene possibly relocated from the chloroplast to the nuclear genome. Excess copper dramatically increased the PmCuZnSOD transcripts and SOD activity in cells, caused by ROS generation and decrease of photosynthetic efficiency in the treated cells. These suggest that CuZnSOD may function to defend against oxidative stress for the survival of the dinoflagellate.
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Affiliation(s)
- Hui Wang
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea
| | - 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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Wang H, Park BS, Lim W, Ki J. CpMCA , a novel metacaspase gene from the harmful dinoflagellate Cochlodinium polykrikoides and its expression during cell death. Gene 2018; 651:70-8. [DOI: 10.1016/j.gene.2018.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 01/26/2018] [Accepted: 02/01/2018] [Indexed: 11/23/2022]
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Wang H, Guo R, Ki JS. 6.0 K microarray reveals differential transcriptomic responses in the dinoflagellate Prorocentrum minimum exposed to polychlorinated biphenyl (PCB). Chemosphere 2018; 195:398-409. [PMID: 29274579 DOI: 10.1016/j.chemosphere.2017.12.066] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 10/23/2017] [Accepted: 12/11/2017] [Indexed: 06/07/2023]
Abstract
Endocrine disrupting chemicals (EDCs) have toxic effects on algae; however, their molecular genomic responses have not been sufficiently elucidated. Here, we evaluated genome-scaled responses of the dinoflagellate alga Prorocentrum minimum exposed to an EDC, polychlorinated biphenyl (PCB), using a 6.0 K microarray. Based on two-fold change cut-off, we identified that 609 genes (∼10.2%) responded to the PCB treatment. KEGG pathway analysis showed that differentially expressed genes (DEGs) were related to ribosomes, biosynthesis of amino acids, spliceosomes, and cellular processes. Many DEGs were involved in cell cycle progression, apoptosis, signal transduction, ion binding, and cellular transportation. In contrast, only a few genes related to photosynthesis and oxidative stress were expressed in response to PCB exposure. This was supported by that fact that there were no obvious changes in the photosynthetic efficiency and reactive oxygen species (ROS) production. These results suggest that PCB might not cause chloroplast and oxidative damage, but could lead to cell cycle arrest and apoptosis. In addition, various signal transduction and transport pathways might be disrupted in the cells, which could further contribute to cell death. These results expand the genomic understanding of the effects of EDCs on this dinoflagellate protist.
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Affiliation(s)
- Hui Wang
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea
| | - Ruoyu Guo
- 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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Abassi S, Wang H, Park BS, Park JW, Ki JS. A Novel Cyclophilin B Gene in the Red Tide Dinoflagellate Cochlodinium polykrikoides: Molecular Characterizations and Transcriptional Responses to Environmental Stresses. Biomed Res Int 2017; 2017:4101580. [PMID: 29226135 DOI: 10.1155/2017/4101580] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 09/13/2017] [Indexed: 11/25/2022]
Abstract
The marine dinoflagellate Cochlodinium polykrikoides is one of the most common ichthyotoxic species that causes harmful algal blooms (HABs), which leads to ecological damage and huge economic loss in aquaculture industries. Cyclophilins (CYPs) belong to the immunophilin superfamily, and they may play a role in the survival mechanisms of the dinoflagellate in stress environments. In the present study, we identified a novel cyclophilin gene from C. polykrikoides and examined physiological and gene transcriptional responses to biocides copper sulphate (CuSO4) and sodium hypochlorite (NaOCl). The full length of CpCYP was 903 bp, ranging from the dinoflagellate splice leader (DinoSL) sequence to the polyA tail, comprising a 639 bp ORF, a 117 bp 5′-UTR, and a 147 bp 3′-UTR. Motif and phylogenetic comparisons showed that CpCYP was affiliated to group B of CYP. In biocide stressors, cell counts, chlorophyll a, and photosynthetic efficiency (Fv/Fm) of C. polykrikoides were considerably decreased in both exposure time- and dose-dependent manners. In addition, CpCYP gene expression was significantly induced after 24 h exposure to the biocide-treated stress conditions. These results indicate an effect of the biocides on the cell physiology and expression profile of CpCYP, suggesting that the gene may play a role in environmental stress responses.
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Pokrzywinski KL, Tilney CL, Warner ME, Coyne KJ. Cell cycle arrest and biochemical changes accompanying cell death in harmful dinoflagellates following exposure to bacterial algicide IRI-160AA. Sci Rep 2017; 7:45102. [PMID: 28332589 PMCID: PMC5362807 DOI: 10.1038/srep45102] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 02/17/2017] [Indexed: 12/02/2022] Open
Abstract
Bacteria may play a role in regulating harmful algal blooms, but little is known about the biochemical and physiological changes associated with cell death induced by algicidal bacteria. Previous work characterized an algicidal exudate (IRI-160AA) produced by Shewanella sp. IRI-160 that is effective against dinoflagellates, while having little to no effect on other phytoplankton species in laboratory culture experiments. The objective of this study was to evaluate biochemical changes associated with cell death and impacts on the cell cycle in three dinoflagellate species (Prorocentrum minimum, Karlodinium veneficum and Gyrodinium instriatum) after exposure to IRI-160AA. In this study, IRI-160AA induced cell cycle arrest in all dinoflagellates examined. Several indicators for programmed cell death (PCD) that are often observed in phytoplankton in response to a variety of stressors were also evaluated. Cell death was accompanied by significant increases in DNA degradation, intra- and extracellular ROS concentrations and DEVDase (caspase-3 like) protease activity, which have been associated with PCD in other phytoplankton species. Overall, results of this investigation provide strong evidence that treatment with the bacterial algicide, IRI-160AA results in cell cycle arrest and induces biochemical changes consistent with stress-related cell death responses observed in other phytoplankton.
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Affiliation(s)
- Kaytee L Pokrzywinski
- College of Earth, Ocean, and Environment, University of Delaware, 700 Pilottown Road, Lewes, DE 19958, USA
| | - Charles L Tilney
- College of Earth, Ocean, and Environment, University of Delaware, 700 Pilottown Road, Lewes, DE 19958, USA
| | - Mark E Warner
- College of Earth, Ocean, and Environment, University of Delaware, 700 Pilottown Road, Lewes, DE 19958, USA
| | - Kathryn J Coyne
- College of Earth, Ocean, and Environment, University of Delaware, 700 Pilottown Road, Lewes, DE 19958, USA
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Guo R, Lim WA, Ki JS. Genome-wide analysis of transcription and photosynthesis inhibition in the harmful dinoflagellate Prorocentrum minimum in response to the biocide copper sulfate. Harmful Algae 2016; 57:27-38. [PMID: 30170719 DOI: 10.1016/j.hal.2016.05.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 06/08/2023]
Abstract
Copper is an essential trace metal for organisms; however, excess copper may damage cellular processes. Their efficiency and physiological effects of biocides have been well documented; however, molecular transcriptome responses to biocides are insufficiently studied. In the present study, a 6.0K oligonucleotide chip was developed to investigate the molecular responses of the harmful dinoflagellate Prorocentrum minimum to copper sulfate (CuSO4) treatment. The results revealed that 515 genes (approximately 8.6%) responded to CuSO4, defined as being within a 2-fold change. Further, KEGG pathway analysis showed that differentially expressed genes (DEGs) were involved in ribosomal function, RNA transport, carbon metabolism, biosynthesis of amino acids, photosystem maintenance, and other cellular processes. Among the DEGs, 49 genes were related to chloroplasts and mitochondria. Furthermore, the genes involved in the RAS signaling pathway, MAPK signaling pathway, and transport pathways were identified. An additional experiment showed that the photosynthesis efficiency decreased considerably, and reactive oxygen species (ROS) production increased in P. minimum after CuSO4 exposure. These results suggest that CuSO4 caused cellular oxidative stress in P. minimum, affecting the ribosome and mitochondria, and severely damaged the photosystem. These effects may potentially lead to cell death, although the dinoflagellate has developed a complex signal transduction process to combat copper toxicity.
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Affiliation(s)
- Ruoyu Guo
- Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul 03016, Republic of Korea
| | - Weol-Ae Lim
- Oceanic Climate & Ecology Research Division, the National Institute of Fisheries Science (NISF), Busan 46083, Republic of Korea
| | - Jang-Seu Ki
- Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul 03016, Republic of Korea.
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Ponmani T, Guo R, Ki JS. A novel cyclophilin gene from the dinoflagellate Prorocentrum minimum and its possible role in the environmental stress response. Chemosphere 2015; 139:260-7. [PMID: 26150195 DOI: 10.1016/j.chemosphere.2015.06.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 06/18/2015] [Accepted: 06/21/2015] [Indexed: 05/20/2023]
Abstract
Cyclophilins (CYPs) are a family of proteins that bind to cyclosporine and are thought to be involved in the stress response. In dinoflagellate algae, CYPs may function as a survival strategy in cells exposed to environmental stressors. Here, we identified a novel cyclophilin gene (referred to as PmCYP, comprising a 516-bp open reading frame, encoding a 171-aa protein with a molecular mass of 17.5kDa) from the dinoflagellate Prorocentrum minimum, and evaluated the role of dinoflagellate CYP in cells exposed to environmental pollutants copper and polychlorinated biphenyl. In addition, we assessed the cytoprotective role of nitric oxide in relation to the expression of PmCYP. These stressors strongly affected the physiology of the cells, as judged by cell counting, reactive oxygen species (ROS) imaging, and photosynthetic parameters (Fv/Fm and PIABS). PmCYP expression was significantly (P<0.05) induced upon exposure of the cells to all the test pollutants used in this study. These clearly indicate that PmCYP plays a vital role in the oxidative stress response in dinoflagellate survival, although the gene was initially known only for its housekeeping function.
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Affiliation(s)
- Thangaraj Ponmani
- Institute of Natural Sciences, Sangmyung University, Seoul 110-743, South Korea
| | - Ruoyu Guo
- Department of Life Science, Sangmyung University, Seoul 110-743, South Korea
| | - Jang-Seu Ki
- Institute of Natural Sciences, Sangmyung University, Seoul 110-743, South Korea; Department of Life Science, Sangmyung University, Seoul 110-743, South Korea.
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Krueger T, Fisher PL, Becker S, Pontasch S, Dove S, Hoegh-Guldberg O, Leggat W, Davy SK. Transcriptomic characterization of the enzymatic antioxidants FeSOD, MnSOD, APX and KatG in the dinoflagellate genus Symbiodinium. BMC Evol Biol 2015; 15:48. [PMID: 25887897 PMCID: PMC4416395 DOI: 10.1186/s12862-015-0326-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 02/24/2015] [Indexed: 11/26/2022] Open
Abstract
Background The diversity of the symbiotic dinoflagellate Symbiodinium sp., as assessed by genetic markers, is well established. To what extent this diversity is reflected on the amino acid level of functional genes such as enzymatic antioxidants that play an important role in thermal stress tolerance of the coral-Symbiodinium symbiosis is, however, unknown. Here we present a predicted structural analysis and phylogenetic characterization of the enzymatic antioxidant repertoire of the genus Symbiodinium. We also report gene expression and enzymatic activity under short-term thermal stress in Symbiodinium of the B1 genotype. Results Based on eight different ITS2 types, covering six clades, multiple protein isoforms for three of the four investigated antioxidants (ascorbate peroxidase [APX], catalase peroxidase [KatG], manganese superoxide dismutase [MnSOD]) are present in the genus Symbiodinium. Amino acid sequences of both SOD metalloforms (Fe/Mn), as well as KatG, exhibited a number of prokaryotic characteristics that were also supported by the protein phylogeny. In contrast to the bacterial form, KatG in Symbiodinium is characterized by extended functionally important loops and a shortened C-terminal domain. Intercladal sequence variations were found to be much higher in both peroxidases, compared to SODs. For APX, these variable residues involve binding sites for substrates and cofactors, and might therefore differentially affect the catalytic properties of this enzyme between clades. While expression of antioxidant genes was successfully measured in Symbiodinium B1, it was not possible to assess the link between gene expression and protein activity due to high variability in expression between replicates, and little response in their enzymatic activity over the three-day experimental period. Conclusions The genus Symbiodinium has a diverse enzymatic antioxidant repertoire that has similarities to prokaryotes, potentially as a result of horizontal gene transfer or events of secondary endosymbiosis. Different degrees of sequence evolution between SODs and peroxidases might be the result of potential selective pressure on the conserved molecular function of SODs as the first line of defence. In contrast, genetic redundancy of hydrogen peroxide scavenging enzymes might permit the observed variations in peroxidase sequences. Our data and successful measurement of antioxidant gene expression in Symbiodinium will serve as basis for further studies of coral health. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0326-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Thomas Krueger
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6140, New Zealand. .,Laboratory for Biological Geochemistry, ENAC, École polytechnique fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland.
| | - Paul L Fisher
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6140, New Zealand. .,School of Civil Engineering, University of Queensland, St Lucia, QLD 4072, Australia.
| | - Susanne Becker
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6140, New Zealand.
| | - Stefanie Pontasch
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6140, New Zealand.
| | - Sophie Dove
- School of Biological Sciences & ARC Centre of Excellence for Coral Reef Studies, University of Queensland, Brisbane, QLD, 4072, Australia.
| | - Ove Hoegh-Guldberg
- Global Change Institute, University of Queensland, Brisbane, QLD 4072, Australia.
| | - William Leggat
- Comparative Genomics Centre, School of Pharmacy and Molecular Sciences & ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia.
| | - Simon K Davy
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6140, New Zealand.
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Ponmani T, Guo R, Suh YS, Ki JS. Molecular characterisation and expression analysis of a novel calreticulin (CRT) gene in the dinoflagellate Prorocentrum minimum. Mol Biol Rep 2014; 42:681-8. [DOI: 10.1007/s11033-014-3815-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 11/04/2014] [Indexed: 11/28/2022]
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Guo R, Ebenezer V, Ki J. PmMGST3, a novel microsomal glutathione S-transferase gene in the dinoflagellate Prorocentrum minimum, is a potential biomarker of oxidative stress. Gene 2014; 546:378-85. [DOI: 10.1016/j.gene.2014.05.046] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 05/13/2014] [Accepted: 05/21/2014] [Indexed: 11/24/2022]
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