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Lu J, Niu X, Wang H, Zhang H, Guan W. Toxic dinoflagellate Karenia mikimotoi induces apoptosis in Neuro-2a cells through an oxidative stress-mediated mitochondrial pathway. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 267:115667. [PMID: 37944466 DOI: 10.1016/j.ecoenv.2023.115667] [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: 06/15/2023] [Revised: 11/01/2023] [Accepted: 11/04/2023] [Indexed: 11/12/2023]
Abstract
The dinoflagellate Karenia mikimotoi is a toxic bloom-forming species that threatens aquaculture and public health worldwide. Previous studies showed that K. mikimotoi induces neurotoxicity; however, the underlying mechanism is poorly understood. In this study, three neural cell lines were used to investigate the potential neurotoxicity of K. mikimotoi. The tested cells were exposed to a ruptured cell solution (RCS) of K. mikimotoi at different concentrations (0.5 × 105, 1.0 × 105, 2.0 × 105, 4.0 × 105, and 6 × 105 cells mL-1) for 24 h, and the RCS decreased cell viabilities and promoted Neuro-2a (N2A) cell apoptosis in a dose-dependent manner. The underlying mechanism was further investigated in N2A cells. At the biochemical level, the RCS stimulated reactive oxygen species (ROS) and malondialdehyde (MDA) formation, decreased SOD activity, and reduced mitochondrial membrane potential (MMP). At the gene level, the moderate RCS treatment (2.0 × 105 cells mL-1) upregulated antioxidant response genes (e.g., nrf-2, HO-1, NQO-1, and cat) to alleviate RCS-induced oxidative stress, while the high RCS treatment (4.0 × 105 cells mL-1) downregulated these genes, thereby aggravating oxidative stress. Meanwhile, apoptosis-related genes (e.g., p53, caspase 3, and bax2) were significantly upregulated and the anti-apoptotic gene bcl2 was suppressed after RCS treatment. Western blotting results for Caspase 3, Bax2 and Bcl2 were consistent with the mRNA trends. These results revealed that K. mikimotoi RCS can induce neural cell apoptosis via the oxidative stress-mediated mitochondrial pathway, providing novel insights into the neurotoxicity of K. mikimotoi.
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Affiliation(s)
- Jinfang Lu
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Xiaoqin Niu
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China; Department of Clinical Laboratory, The First Hospital of Jiaxing, The Affiliated Hospital of Jiaxing University, Jiaxing 314000, China
| | - Hong Wang
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - He Zhang
- Zhejiang Provincial Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection, National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, College of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang 325035, China.
| | - Wanchun Guan
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China; Institute of Marine Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
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2
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Wan X, Yao G, Wang K, Bao S, Han P, Wang F, Song T, Jiang H. Transcriptomic analysis of polyketide synthesis in dinoflagellate, Prorocentrum lima. HARMFUL ALGAE 2023; 123:102391. [PMID: 36894212 DOI: 10.1016/j.hal.2023.102391] [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: 08/30/2022] [Revised: 12/31/2022] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
The benthic dinoflagellate Prorocentrum lima is among the most common toxic morphospecies with a cosmopolitan distribution. P. lima can produce polyketide compounds, such as okadaic acid (OA), dinophysistoxin (DTX) and their analogues, which are responsible for diarrhetic shellfish poisoning (DSP). Studying the molecular mechanism of DSP toxin biosynthesis is crucial for understanding the environmental driver influencing toxin biosynthesis as well as for better monitoring of marine ecosystems. Commonly, polyketides are produced by polyketide synthases (PKS). However, no gene has been confirmatively assigned to DSP toxin production. Here, we assembled a transcriptome from 94,730,858 Illumina RNAseq reads using Trinity, resulting in 147,527 unigenes with average sequence length of 1035 nt. Using bioinformatics analysis methods, we found 210 unigenes encoding single-domain PKS with sequence similarity to type I PKSs, as reported in other dinoflagellates. In addition, 15 transcripts encoding multi-domain PKS (forming typical type I PKSs modules) and 5 transcripts encoding hybrid nonribosomal peptide synthetase (NRPS)/PKS were found. Using comparative transcriptome and differential expression analysis, a total of 16 PKS genes were identified to be up-regulated in phosphorus-limited cultures, which was related to the up regulation of toxin expression. In concert with other recent transcriptome analyses, this study contributes to the building consensus that dinoflagellates may utilize a combination of Type I multi-domain and single-domain PKS proteins, in an as yet undefined manner, to synthesize polyketides. Our study provides valuable genomic resource for future research in order to understand the complex mechanism of toxin production in this dinoflagellate.
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Affiliation(s)
- Xiukun Wan
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Ge Yao
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Kang Wang
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Shaoheng Bao
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Penggang Han
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Fuli Wang
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Tianyu Song
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Hui Jiang
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China.
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Chen H, Wang J, Zhuang Y, Yu W, Liu G. Reduced Fitness and Elevated Oxidative Stress in the Marine Copepod Tigriopus japonicus Exposed to the Toxic Dinoflagellate Karenia mikimotoi. Antioxidants (Basel) 2022; 11:2299. [PMID: 36421485 PMCID: PMC9687495 DOI: 10.3390/antiox11112299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 11/13/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022] Open
Abstract
Blooms of the toxic dinoflagellate Karenia mikimotoi cause devastation to marine life, including declines of fitness and population recruitment. However, little is known about the effects of them on benthic copepods. Here, we assessed the acute and chronic effects of K. mikimotoi on the marine benthic copepod Tigriopus japonicus. Results showed that adult females maintained high survival (>85%) throughout 14-d incubation, but time-dependent reduction of survival was detected in the highest K. mikimotoi concentration, and nauplii and copepodites were more vulnerable compared to adults. Ingestion of K. mikimotoi depressed the grazing of copepods but significantly induced the generation of reactive oxygen species (ROS), total antioxidant capacity, activities of antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase), and acetylcholinesterase. Under sublethal concentrations for two generations, K. mikimotoi reduced the fitness of copepods by prolonging development time and decreasing successful development rate, egg production, and the number of clutches. Our findings suggest that the bloom of K. mikimotoi may threaten copepod population recruitment, and its adverse effects are associated with oxidative stress.
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Affiliation(s)
- Hongju Chen
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
- Laboratory for Marine Ecology and Environmental Science Laboratory, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Jing Wang
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
| | - Yunyun Zhuang
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
- Laboratory for Marine Ecology and Environmental Science Laboratory, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Wenzhuo Yu
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
| | - Guangxing Liu
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
- Laboratory for Marine Ecology and Environmental Science Laboratory, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
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Lin S, Yu L, Wu X, Li M, Zhang Y, Luo H, Li H, Li T, Li L. Active meiosis during dinoflagellate blooms: A 'sex for proliferation' hypothesis. HARMFUL ALGAE 2022; 118:102307. [PMID: 36195414 DOI: 10.1016/j.hal.2022.102307] [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: 07/21/2022] [Revised: 08/05/2022] [Accepted: 08/05/2022] [Indexed: 06/16/2023]
Abstract
In dinoflagellates, sexual reproduction is best known to be induced by adverse environmental conditions and culminate in encystment for survival ('sex for encystment'). Although increasing laboratory observations indicate that sex can lead to production of vegetative cells bypassing encystment, the occurrence of this alternative pathway in natural populations and its ecological roles remain poorly understood. Here we report evidence that sex in dinoflagellates can potentially be an instrument for bloom proliferation or extension. By bloom metatranscriptome profiling, we documented elevated expression of meiosis genes in two evolutionarily distinct species (Prorocentrum shikokuense and Karenia mikimotoi) during bloom, a timing unexpected of the 'sex for encystment' scenario. To link these genes to meiosis, we induced encystment and cyst germination in the cyst-forming species Scrippsiella acuminata, and found that five of these genes were upregulated during cyst germination, when meiosis occurs. Integrating data from all three species revealed that SPO11, MND1, and DMC1 were likely common between cyst-forming and non-encysting sex in dinoflagellates. Furthermore, flow cytometric analyses revealed consecutive rounds of DNA halving during blooms of P. shikokuense and K. mikimotoi, evidencing meiosis. These data provided novel evidence that sexual reproduction in dinoflagellates might serve to promote cell proliferation, and along with the consequent enhancement of genetic diversity facilitating resistance against pathogens and environmental stress, to boost or extend a bloom ('sex for proliferation'). The putative meiosis-specific genes and insights reported here will prove to be helpful for rigorously testing the hypothesis and addressing whether the two modes of sex are genetically predisposed (i.e. species-specific) or environmentally induced (switchable within species), and if the latter what triggers the switch.
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Affiliation(s)
- Senjie Lin
- Department of Marine Sciences, University of Connecticut, Groton, CT 06340, USA.
| | - Liying Yu
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Xiaomei Wu
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Meizhen Li
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Yaqun Zhang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Hao Luo
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Hongfei Li
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Tangcheng Li
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Ling Li
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian 361102, China
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D’Ambrosio HK, Ganley JG, Keeler AM, Derbyshire ER. A single amino acid residue controls acyltransferase activity in a polyketide synthase from Toxoplasma gondii. iScience 2022; 25:104443. [PMID: 35874921 PMCID: PMC9301873 DOI: 10.1016/j.isci.2022.104443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 04/12/2022] [Accepted: 05/16/2022] [Indexed: 11/17/2022] Open
Abstract
Type I polyketide synthases (PKSs) are multidomain, multimodule enzymes capable of producing complex polyketide metabolites. These modules contain an acyltransferase (AT) domain, which selects acyl-CoA substrates to be incorporated into the metabolite scaffold. Herein, we reveal the sequences of three AT domains from a polyketide synthase (TgPKS2) from the apicomplexan parasite Toxoplasma gondii. Phylogenic analysis indicates these ATs (AT1, AT2, and AT3) are distinct from domains in well-characterized microbial biosynthetic gene clusters. Biochemical investigations revealed that AT1 and AT2 hydrolyze malonyl-CoA but the terminal AT3 domain is non-functional. We further identify an "on-off switch" residue that controls activity such that a single amino acid change in AT3 confers hydrolysis activity while the analogous mutation in AT2 eliminates activity. This biochemical analysis of AT domains from an apicomplexan PKS lays the foundation for further molecular and structural studies on PKSs from T. gondii and other protists.
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Affiliation(s)
- Hannah K. D’Ambrosio
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC 27708, USA
| | - Jack G. Ganley
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC 27708, USA
| | - Aaron M. Keeler
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC 27708, USA
| | - Emily R. Derbyshire
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC 27708, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, 213 Research Drive, Durham, NC 27710, USA
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Guo X, Han T, Tan L, Zhao T, Zhu X, Huang W, Lin K, Zhang N, Wang J. The allelopathy and underlying mechanism of Skeletonema costatum on Karenia mikimotoi integrating transcriptomics profiling. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 242:106042. [PMID: 34861574 DOI: 10.1016/j.aquatox.2021.106042] [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: 07/03/2021] [Revised: 11/08/2021] [Accepted: 11/20/2021] [Indexed: 06/13/2023]
Abstract
The roles of allelopathy for succession of marine phytoplankton communities remain controversial, especially for the development of blooms. Physiological parameters measurement (Fv/Fm value, MDA content, SOD activity, Na+/K+, Ca2+/ Mg2+-ATPase activity, cell size, chlorophyll content, apoptosis and cell cycle) and whole transcriptome profiling analysis were used to investigate allelopathy effect of Skeletonema costatum on Karenia mikimotoi. Filtrate and extracts from S. costatum culture inhibited the growth of K. mikimotoi. Allelopathic effects were dose-dependent for filtrate culture and extract culture. K. mikimotoi scavenged excessive ROS and adapted to the stress fastly and easily, so oxidative damage was not the main cause of the growth inhibition. Allelochemicals of S. costatum were found to influence the structure and function of cell membrane of K. mikimotoi by damaging membrane structure till to cell necrosis, which caused high mortality. Coupled with the sensitivity of algal cells to environmental stress and restricted cell cycle, allelopathy was suggested to be deeply detrimental to the development of competition algal population.
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Affiliation(s)
- Xin Guo
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
| | - Tongzhu Han
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
| | - Liju Tan
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
| | - Ting Zhao
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China; Eco-Environmental Monitoring and Research Center, Pearl River Valley and South China Sea Ecology and Environment Administration, Ministry of Ecology and Environment, PCR, Guangzhou, 510610, China
| | - Xiaolin Zhu
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
| | - Wenqiu Huang
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
| | - Kun Lin
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
| | - Na Zhang
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
| | - Jiangtao Wang
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China.
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Remize M, Planchon F, Garnier M, Loh AN, Le Grand F, Bideau A, Lambert C, Corvaisier R, Volety A, Soudant P. A 13CO 2 Enrichment Experiment to Study the Synthesis Pathways of Polyunsaturated Fatty Acids of the Haptophyte Tisochrysis lutea. Mar Drugs 2021; 20:md20010022. [PMID: 35049877 PMCID: PMC8779623 DOI: 10.3390/md20010022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/03/2021] [Accepted: 12/14/2021] [Indexed: 11/26/2022] Open
Abstract
The production of polyunsaturated fatty acids (PUFA) in Tisochrysis lutea was studied using the gradual incorporation of a 13C-enriched isotopic marker, 13CO2, for 24 h during the exponential growth of the algae. The 13C enrichment of eleven fatty acids was followed to understand the synthetic pathways the most likely to form the essential polyunsaturated fatty acids 20:5n-3 (EPA) and 22:6n-3 (DHA) in T. lutea. The fatty acids 16:0, 18:1n-9 + 18:3n-3, 18:2n-6, and 22:5n-6 were the most enriched in 13C. On the contrary, 18:4n-3 and 18:5n-3 were the least enriched in 13C after long chain polyunsaturated fatty acids such as 20:5n-3 or 22:5n-3. The algae appeared to use different routes in parallel to form its polyunsaturated fatty acids. The use of the PKS pathway was hypothesized for polyunsaturated fatty acids with n-6 configuration (such as 22:5n-6) but might also exist for n-3 PUFA (especially 20:5n-3). With regard to the conventional n-3 PUFA pathway, Δ6 desaturation of 18:3n-3 appeared to be the most limiting step for T. lutea, “stopping” at the synthesis of 18:4n-3 and 18:5n-3. These two fatty acids were hypothesized to not undergo any further reaction of elongation and desaturation after being formed and were therefore considered “end-products”. To circumvent this limiting synthetic route, Tisochrysis lutea seemed to have developed an alternative route via Δ8 desaturation to produce longer chain fatty acids such as 20:5n-3 and 22:5n-3. 22:6n-3 presented a lower enrichment and appeared to be produced by a combination of different pathways: the conventional n-3 PUFA pathway by desaturation of 22:5n-3, the alternative route of ω-3 desaturase using 22:5n-6 as precursor, and possibly the PKS pathway. In this study, PKS synthesis looked particularly effective for producing long chain polyunsaturated fatty acids. The rate of enrichment of these compounds hypothetically synthesized by PKS is remarkably fast, making undetectable the 13C incorporation into their precursors. Finally, we identified a protein cluster gathering PKS sequences of proteins that are hypothesized allowing n-3 PUFA synthesis.
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Affiliation(s)
- Marine Remize
- UMR 6539 LEMAR, CNRS, IRD, Ifremer, University of Brest, 29280 Plouzane, France; (F.P.); (F.L.G.); (A.B.); (C.L.); (R.C.)
- GREENSEA, Promenade du Sergeant Navarro, 34140 Meze, France
- Correspondence: (M.R.); (P.S.)
| | - Frédéric Planchon
- UMR 6539 LEMAR, CNRS, IRD, Ifremer, University of Brest, 29280 Plouzane, France; (F.P.); (F.L.G.); (A.B.); (C.L.); (R.C.)
| | - Matthieu Garnier
- PBA, Ifremer, Rue de l’Ile d’Yeu, BP 21105, CEDEX 03, 44311 Nantes, France;
| | - Ai Ning Loh
- Center for Marine Science, Department of Earth and Ocean Sciences, University of North Carolina Wilmington, 5600 Marvin K. Moss Ln, Wilmington, NC 28403, USA;
| | - Fabienne Le Grand
- UMR 6539 LEMAR, CNRS, IRD, Ifremer, University of Brest, 29280 Plouzane, France; (F.P.); (F.L.G.); (A.B.); (C.L.); (R.C.)
| | - Antoine Bideau
- UMR 6539 LEMAR, CNRS, IRD, Ifremer, University of Brest, 29280 Plouzane, France; (F.P.); (F.L.G.); (A.B.); (C.L.); (R.C.)
| | - Christophe Lambert
- UMR 6539 LEMAR, CNRS, IRD, Ifremer, University of Brest, 29280 Plouzane, France; (F.P.); (F.L.G.); (A.B.); (C.L.); (R.C.)
| | - Rudolph Corvaisier
- UMR 6539 LEMAR, CNRS, IRD, Ifremer, University of Brest, 29280 Plouzane, France; (F.P.); (F.L.G.); (A.B.); (C.L.); (R.C.)
| | - Aswani Volety
- 50 Campus Drive, Elon University, Elon, NC 27244, USA;
| | - Philippe Soudant
- UMR 6539 LEMAR, CNRS, IRD, Ifremer, University of Brest, 29280 Plouzane, France; (F.P.); (F.L.G.); (A.B.); (C.L.); (R.C.)
- Correspondence: (M.R.); (P.S.)
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Niu X, Xu S, Yang Q, Xu X, Zheng M, Li X, Guan W. Toxic effects of the dinoflagellate Karenia mikimotoi on zebrafish (Danio rerio) larval behavior. HARMFUL ALGAE 2021; 103:101996. [PMID: 33980436 DOI: 10.1016/j.hal.2021.101996] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/28/2021] [Accepted: 01/31/2021] [Indexed: 06/12/2023]
Abstract
Karenia mikimotoi is a toxic dinoflagellate that forms harmful blooms in coastal waters, threatening aquaculture worldwide. However, we do not know whether K. mikimotoi has a neurotoxic effect on aquatic animal behavior. Thus, this study investigated potential K. mikimotoi neurotoxicity in zebrafish larvae. Cells of K. mikimotoi were collected at the mid-exponential phase from a batch culture to prepare ruptured cell solutions (RCS). At 6 h post-fertilization (hpf), zebrafish embryos were exposed to different RCS concentrations (0, 102, 103, 104, and 2.5 × 104 cells mL-1). After 120 hpf, treated larvae were collected to analyze locomotor behavior; activities of acetylcholinesterase (AChE), superoxide dismutase (SOD), catalase (CAT); and expression of genes related to neurodevelopment. We found that RCS did not affect survival rate, but significantly decreased larval locomotion, as well as their AChE, SOD, and CAT activity. Additionally, the examination of the day-night behavioral experiment revealed RCS decreased locomotion only at night. Zebrafish larvae were also significantly hypoactive in response to light and sound stimulations. Of the neurodevelopment genes, three (th, neurog1, and neurod1) were downregulated, while two (bdnf and manf) were upregulated. Our study suggests that K. mikimotoi neurotoxicity occurs through causing oxidative damage, as well as disorders in the cholinergic system and nervous system development. The results provide new insight that K. mikimotoi in low abundance did not cause significant lethal effect but still exhibited significant neurotoxicity on aquatic animals.
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Affiliation(s)
- Xiaoqin Niu
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China 325035
| | - Shengnan Xu
- The Affiliated Kangning Hospital of Wenzhou Medical University, Wenzhou 325035, Zhejiang, China
| | - Qiongying Yang
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China 325035
| | - Xuelian Xu
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China 325035
| | - Miaomiao Zheng
- The Affiliated Kangning Hospital of Wenzhou Medical University, Wenzhou 325035, Zhejiang, China
| | - Xi Li
- The Affiliated Kangning Hospital of Wenzhou Medical University, Wenzhou 325035, Zhejiang, China.
| | - Wanchun Guan
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China 325035.
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Durán-Vinet B, Araya-Castro K, Chao TC, Wood SA, Gallardo V, Godoy K, Abanto M. Potential applications of CRISPR/Cas for next-generation biomonitoring of harmful algae blooms: A review. HARMFUL ALGAE 2021; 103:102027. [PMID: 33980455 DOI: 10.1016/j.hal.2021.102027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/01/2021] [Accepted: 03/21/2021] [Indexed: 06/12/2023]
Abstract
Research on harmful algal and cyanobacterial blooms (HABs and CHABs) has risen dramatically due to their increasing global distribution, frequency, and intensity. These blooms jeopardize public health, ecosystem function, sustainability and can have negative economic impacts. Numerous monitoring programs have been established using light microscopy, liquid chromatography coupled to mass spectrometry (LC-MS), ELISA, and spectrophotometry to monitor HABs/CHABs outbreaks. Recently, DNA/RNA-based molecular methods have been integrated into these programs to replace or complement traditional methods through analyzing environmental DNA and RNA (eDNA/eRNA) with techniques such as quantitative polymerase chain reaction (qPCR), fluorescent in situ hybridization (FISH), sandwich hybridization assay (SHA), isothermal amplification methods, and microarrays. These have enabled the detection of rare or cryptic species, enhanced sample throughput, and reduced costs and the need for visual taxonomic expertise. However, these methods have limitations, such as the need for high capital investment in equipment or detection uncertainties, including determining whether organisms are viable. In this review, we discuss the potential of newly developed molecular diagnosis technology based on Clustered Regularly Interspaced Short Palindromic Repeats/Cas proteins (CRISPR/Cas), which utilizes the prokaryotic adaptative immune systems of bacteria and archaea. Cas12 and Cas13-based platforms can detect both DNA and RNA with attomolar sensitivity within an hour. CRISPR/Cas diagnostic is a rapid, inexpensive, specific, and ultrasensitive technology that, with some further development, will provide many new platforms that can be used for HABs/CHABs biomonitoring and research.
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Affiliation(s)
- B Durán-Vinet
- Scientific and Technological Bioresource Nucleus (BIOREN-UFRO), Genomics and Bioinformatics Unit, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile; Bachelor of Biotechnology (Honours) Program, Faculty of Agricultural and Forestry Sciences, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile.
| | - K Araya-Castro
- Doctoral Program in Science of Natural Resources, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile
| | - T C Chao
- Institute of Environmental Change & Society, Department of Biology, University of Regina, Wascana Parkway, 3737 Regina, Canada
| | - S A Wood
- Coastal and Freshwater Group, Cawthron Institute, 98 Halifax Street East, Nelson 7010, New Zealand
| | - V Gallardo
- Scientific and Technological Bioresource Nucleus (BIOREN-UFRO), Genomics and Bioinformatics Unit, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile; Bachelor of Biotechnology (Honours) Program, Faculty of Agricultural and Forestry Sciences, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile
| | - K Godoy
- Scientific and Technological Bioresource Nucleus (BIOREN-UFRO), Microscopy and Flow Cytometry Unit, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile
| | - M Abanto
- Scientific and Technological Bioresource Nucleus (BIOREN-UFRO), Genomics and Bioinformatics Unit, Universidad de La Frontera, Av. Francisco Salazar, 1145 Temuco, Chile
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10
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Remize M, Brunel Y, Silva JL, Berthon JY, Filaire E. Microalgae n-3 PUFAs Production and Use in Food and Feed Industries. Mar Drugs 2021; 19:113. [PMID: 33670628 PMCID: PMC7922858 DOI: 10.3390/md19020113] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/13/2021] [Accepted: 02/15/2021] [Indexed: 12/11/2022] Open
Abstract
N-3 polyunsaturated fatty acids (n-3 PUFAs), and especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are essential compounds for human health. They have been proven to act positively on a panel of diseases and have interesting anti-oxidative, anti-inflammatory or anti-cancer properties. For these reasons, they are receiving more and more attention in recent years, especially future food or feed development. EPA and DHA come mainly from marine sources like fish or seaweed. Unfortunately, due to global warming, these compounds are becoming scarce for humans because of overfishing and stock reduction. Although increasing in recent years, aquaculture appears insufficient to meet the increasing requirements of these healthy molecules for humans. One alternative resides in the cultivation of microalgae, the initial producers of EPA and DHA. They are also rich in biochemicals with interesting properties. After defining macro and microalgae, this review synthesizes the current knowledge on n-3 PUFAs regarding health benefits and the challenges surrounding their supply within the environmental context. Microalgae n-3 PUFA production is examined and its synthesis pathways are discussed. Finally, the use of EPA and DHA in food and feed is investigated. This work aims to define better the issues surrounding n-3 PUFA production and supply and the potential of microalgae as a sustainable source of compounds to enhance the food and feed of the future.
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Affiliation(s)
- Marine Remize
- GREENSEA, 3 Promenade du Sergent Jean-Louis Navarro, 34140 MÈZE, France; (M.R.); (Y.B.)
| | - Yves Brunel
- GREENSEA, 3 Promenade du Sergent Jean-Louis Navarro, 34140 MÈZE, France; (M.R.); (Y.B.)
| | - Joana L. Silva
- ALLMICROALGAE–Natural Products, Avenida 25 Abril, 2445-413 Pataias, Portugal;
| | | | - Edith Filaire
- GREENTECH, Biopôle Clermont-Limagne, 63360 SAINT BEAUZIRE, France;
- ECREIN Team, UMR 1019 INRA-UcA, UNH (Human Nutrition Unity), University Clermont Auvergne, 63000 Clermont-Ferrand, France
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11
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Recent Progress in the Study of Peroxiredoxin in the Harmful Algal Bloom Species Chattonella marina. Antioxidants (Basel) 2021; 10:antiox10020162. [PMID: 33499182 PMCID: PMC7911785 DOI: 10.3390/antiox10020162] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 01/17/2021] [Accepted: 01/19/2021] [Indexed: 02/06/2023] Open
Abstract
Peroxiredoxin (Prx) is a relatively recently discovered antioxidant enzyme family that scavenges peroxides and is known to be present in organisms from biological taxa ranging from bacteria to multicellular eukaryotes, including photosynthetic organisms. Although there have been many studies of the Prx family in higher plants, green algae, and cyanobacteria, few studies have concerned raphidophytes and dinoflagellates, which are among the eukaryotic algae that cause harmful algal blooms (HABs). In our proteomic study using 2-D electrophoresis, we found a highly expressed 2-Cys peroxiredoxin (2-CysPrx) in the raphidophyte Chattonella marina var. antiqua, a species that induces mass mortality of aquacultured fish. The abundance of the C. marina 2-CysPrx enzyme was highest in the exponential growth phase, during which photosynthetic activity was high, and it then decreased by about a factor of two during the late stationary growth phase. This pattern suggested that 2-CysPrx is a key enzyme involved in the maintenance of high photosynthesis activity. In addition, the fact that the depression of photosynthesis by excessively high irradiance was more severe in the 2-CysPrx low-expression strain (wild type) than in the normal-expression strain (wild type) of C. marina suggested that 2-CysPrx played a critical role in protecting the cell from oxidative stress caused by exposure to excessively high irradiance. In the field of HAB research, estimates of growth potential have been desired to predict the population dynamics of HABs for mitigating damage to fisheries. Therefore, omics approaches have recently begun to be applied to elucidate the physiology of the growth of HAB species. In this review, we describe the progress we have made using a molecular physiological approach to identify the roles of 2-CysPrx and other antioxidant enzymes in mitigating environmental stress associated with strong light and high temperatures and resultant oxidative stress. We also describe results of a survey of expressed Prx genes and their growth-phase-dependent behavior in C. marina using RNA-seq analysis. Finally, we speculate about the function of these genes and the ecological significance of 2-CysPrx, such as its involvement in circadian rhythms and the toxicity of C. marina to fish.
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12
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Identification of Polyunsaturated Fatty Acids Synthesis Pathways in the Toxic Dinophyte Alexandrium minutum Using 13C-Labelling. Biomolecules 2020; 10:biom10101428. [PMID: 33050104 PMCID: PMC7600785 DOI: 10.3390/biom10101428] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/26/2020] [Accepted: 10/07/2020] [Indexed: 11/16/2022] Open
Abstract
The synthetic pathways responsible for the production of the polyunsaturated fatty acids 22:6n-3 and 20:5n-3 were studied in the Dinophyte Alexandrium minutum. The purpose of this work was to follow the progressive incorporation of an isotopic label (13CO2) into 11 fatty acids to better understand the fatty acid synthesis pathways in A. minutum. The Dinophyte growth was monitored for 54 h using high-frequency sampling. A. minutum presented a growth in two phases. A lag phase was observed during the first 30 h of development and had been associated with the probable temporary encystment of Dinophyte cells. An exponential growth phase was then observed after t30. A. minutum rapidly incorporated 13C into 22:6n-3, which ended up being the most 13C-enriched polyunsaturated fatty acid (PUFA) in this experiment, with a higher 13C atomic enrichment than 18:4n-3, 18:5n-3, 20:5n-3, and 22:5n-3. Overall, the 13C atomic enrichment (AE) was inversely proportional to number of carbons in n-3 PUFA. C18 PUFAs, 18:4n-3, and 18:5n-3, were indeed among the least 13C-enriched FAs during this experiment. They were assumed to be produced by the n-3 PUFA pathway. However, they could not be further elongated or desaturated to produce n-3 C20-C22 PUFA, because the AEs of the n-3 C18 PUFAs were lower than those of the n-3 C20-C22 PUFAs. Thus, the especially high atomic enrichment of 22:6n-3 (55.8% and 54.9% in neutral lipids (NLs) and polar lipids (PLs), respectively) led us to hypothesize that this major PUFA was synthesized by an O2-independent Polyketide Synthase (PKS) pathway. Another parallel PKS, independent of the one leading to 22:6n-3, was also supposed to produce 20:5n-3. The inverse order of the 13C atomic enrichment for n-3 PUFAs was also suspected to be related to the possible β-oxidation of long-chain n-3 PUFAs occurring during A. minutum encystment.
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13
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Cusick KD, Widder EA. Bioluminescence and toxicity as driving factors in harmful algal blooms: Ecological functions and genetic variability. HARMFUL ALGAE 2020; 98:101850. [PMID: 33129462 DOI: 10.1016/j.hal.2020.101850] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 05/29/2020] [Accepted: 06/02/2020] [Indexed: 06/11/2023]
Abstract
Dinoflagellates are an ecologically important group of marine microbial eukaryotes with a remarkable array of adaptive strategies. It is ironic that two of the traits for which dinoflagellates are best known, toxin production and bioluminescence, are rarely linked when considering the ecological significance of either. Although dinoflagellate species that form some of the most widespread and frequent harmful algal blooms (HABs) are bioluminescent, the molecular and eco-evolutionary associations between these two traits has received little attention. Here, the major themes of biochemistry and genetics, ecological functions, signaling mechanisms, and evolution are addressed, with parallels and connections drawn between the two. Of the 17 major classes of dinoflagellate toxins, only two are produced by bioluminescent species: saxitoxin (STX) and yessotoxin. Of these, STX has been extensively studied, including the identification of the STX biosynthetic genes. While numerous theories have been put forward as to the eco-evolutionary roles of both bioluminescence and toxicity, a general consensus is that both function as grazing deterrents. Thus, both bioluminescence and toxicity may aid in HAB initiation as they alleviate grazing pressure on the HAB species. A large gap in our understanding is the genetic variability among natural bloom populations, as both toxic and non-toxic strains have been isolated from the same geographic location. The same applies to bioluminescence, as there exist both bioluminescent and non-bioluminescent strains of the same species. Recent evidence demonstrating that blooms are not monoclonal events necessitates a greater level of understanding as to the genetic variability of these traits among sub-populations as well as the mechanisms by which cells acquire or lose the trait, as sequence analysis of STX+ and STX- species indicate the key gene required for toxicity is lost rather than gained. While the extent of genetic variability for both bioluminescence and toxicity among natural HAB sub-populations remains unknown, it is an area that needs to be explored in order to gain greater insights into the molecular mechanisms and environmental parameters driving HAB evolution.
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Affiliation(s)
- Kathleen D Cusick
- University of Maryland Baltimore County, Department of Biological Sciences, 1000 Hilltop Circle, Baltimore, MD 21250, United States.
| | - Edith A Widder
- Ocean Research and Conservation Association, 1420 Seaway Dr, Fort Pierce, FL 34949, United States.
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14
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Wang H, Kim H, Ki JS. Transcriptome survey and toxin measurements reveal evolutionary modification and loss of saxitoxin biosynthesis genes in the dinoflagellates Amphidinium carterae and Prorocentrum micans. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 195:110474. [PMID: 32200147 DOI: 10.1016/j.ecoenv.2020.110474] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/09/2020] [Accepted: 03/11/2020] [Indexed: 06/10/2023]
Abstract
In the present study, we characterized the potential toxin genes for polyketide synthase (PKS) and saxitoxin (STX) biosynthesis using the transcriptomes of two non-STX producing dinoflagellates Amphidinium carterae and Prorocentrum micans. RNA sequencing revealed 94 and 166 PKS contigs in A. carterae and P. micans, respectively. We first detected type III PKS, which was closely related to bacteria. In addition, dozens of homologs of 20 STX biosynthesis genes were identified. Interestingly, the core STX-synthesizing genes sxtA and sxtB were only found in P. micans, whereas sxtD was detected in A. carterae alone. Bioinformatic analysis showed that the first two core genes (sxtA and sxtG) had a low sequence similarity (37.0-67.6%) and different domain organization compared to those of other toxigenic dinoflagellates, such as Alexandrium pacificum. These might result in the breakdown of the initial reactions in STX production and ultimately the loss of the ability to synthesize the toxins in both dinoflagellates. Our findings suggest that toxin-related PKS and sxt genes are commonly found in non-STX producing dinoflagellates. In addition to their involvement in the synthesis of toxins, our result indicates that genes may also have other molecular metabolic functions.
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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
| | - Jang-Seu Ki
- Department of Biotechnology, Sangmyung University, Seoul, 03016, South Korea.
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15
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Wu Z, Luo H, Yu L, Lee WH, Li L, Mak YL, Lin S, Lam PKS. Characterizing ciguatoxin (CTX)- and Non-CTX-producing strains of Gambierdiscus balechii using comparative transcriptomics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 717:137184. [PMID: 32084685 DOI: 10.1016/j.scitotenv.2020.137184] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/28/2020] [Accepted: 02/06/2020] [Indexed: 06/10/2023]
Abstract
Gambierdiscus spp. can produce the polyketide compound, ciguatoxin (CTX), and are hence responsible for ciguatera fish poisoning (CFP). Studying the molecular mechanism that regulates CTX production is crucial for understanding the environmental trigger of CTX as well as for better informing fishery management. Commonly, polyketide synthases are important for polyketide synthesis; however, no gene has been confirmatively assigned to CTX production. Here, suppression subtractive hybridization (SSH) and transcriptome sequencing (RNA-Seq) were used to compare a CTX-producing strain with a non-CTX-producing strain. Using both methods, a total of 52 polyketide synthase (PKS) genes were identified to be up-regulated in the CTX-producing G. balechii, including transcripts encoding single-domain PKSs as well as transcripts encoding multi-domain PKSs. Using reverse transcription quantitative PCR, the expression of these genes in the CTX-producing strain and in nitrogen-limited cultures of the strain was further documented. These data suggest that PKSs are likely involved in polyketide synthesis and potentially in CTX synthesis in this dinoflagellate species. Our study provides the candidate biomarkers for the detection of CTXs or CFP in waters or any other organisms as well as a valuable genomic resource for the research on Gambierdiscus and other dinoflagellates.
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Affiliation(s)
- Zhen Wu
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China; Department of Chemistry, City University of Hong Kong, Hong Kong, China
| | - Hao Luo
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Liying Yu
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Wai Hin Lee
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China; Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Ling Li
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Yim Ling Mak
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China; Shenzhen Key Laboratory for the Sustainable Use of Marine Biodiversity, Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
| | - Senjie Lin
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China; Department of Marine Sciences, University of Connecticut, Groton, CT, USA.
| | - Paul K S Lam
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China; Department of Chemistry, City University of Hong Kong, Hong Kong, China; Shenzhen Key Laboratory for the Sustainable Use of Marine Biodiversity, Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
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16
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Wang H, Guo R, Lim WA, Allen AE, Ki JS. Comparative transcriptomics of toxin synthesis genes between the non-toxin producing dinoflagellate Cochlodinium polykrikoides and toxigenic Alexandrium pacificum. HARMFUL ALGAE 2020; 93:101777. [PMID: 32307068 DOI: 10.1016/j.hal.2020.101777] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 02/13/2020] [Accepted: 02/19/2020] [Indexed: 06/11/2023]
Abstract
In the present study, we extensively characterized potential toxin-related genes, including polyketide synthase (PKS), saxitoxin (STX) and fatty acid synthase (FAS) from the non-toxin producing marine dinoflagellate Cochlodinium polykrikoides, comparing to those of a toxigenic dinoflagellate Alexandrium pacificum. RNA sequencing revealed 50 and 271 PKS contigs from C. polykrikoides and A. pacificum, respectively. According to domain constitute and amino acid alteration, we further classified the dinoflagellate type I PKS genes into 4 sub-groups. Type III PKS was first identified in C. polykrikoides. Interestingly, we detected a large number (242 and 288) of homologs of 18 sxt genes from two studied dinoflagellates. Most of the eight key genes (sxtA, sxtB, sxtD, sxtG, sxtH/T, sxtI, sxtS and sxtU) for STX synthesis were detected in both dinoflatellates, whereas a core STX biosynthesis gene sxtG was not detected in C. polykrikoides. This may partially explain the absence of saxitoxin production in C. polykrikoides. In addition, we identified several type I and type II FAS genes, including FabD, FabF, FabG, FabH, FabI, and FabZ, whereas FabB was not found in C. polykrikoides. Overall, the numbers of the toxin-related genes in C. polykrikoides were less than that of A. pacificum. Phylogenetic analyses showed that type I PKS/FASs of dinoflagellates had close relationships with apicomplexans and bacteria. These suggest that the toxin-related PKS and sxt genes are commonly present in toxigenic and non-toxin producing dinoflagellates, and may be involved not only in the toxin synthesis, but also in other related molecular metabolic functions.
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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; Key Laboratory of Marine Ecosystem and Biogeochemistry, State Oceanic Administration & Second Institute of Oceanography, Ministry of Natural Resources, PR China
| | - Weol-Ae Lim
- Ocean Climate and Ecology Research Division, National Institute of Fisheries Science (NIFS), Busan 46083, South Korea
| | - Andrew E Allen
- Scripps Institution of Oceanography, University of California, San Diego, CA 92093, USA; Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA 92037, USA
| | - Jang-Seu Ki
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea.
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17
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Li X, Yan T, Yu R, Zhou M. A review of karenia mikimotoi: Bloom events, physiology, toxicity and toxic mechanism. HARMFUL ALGAE 2019; 90:101702. [PMID: 31806160 DOI: 10.1016/j.hal.2019.101702] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/10/2019] [Accepted: 10/28/2019] [Indexed: 06/10/2023]
Abstract
Karenia mikimotoi is a worldwide bloom-forming dinoflagellate in the genus Karenia. Blooms of this alga have been observed since the 1930s and have caused mass mortalities of fish, shellfish, and other invertebrates in the coastal waters of many countries, including Japan, Norway, Ireland, and New Zealand. This species has frequently bloomed in China, causing great financial losses (more than 2 billion yuan, Fujian Province, 2012). K. mikimotoi can adapt to various light, temperature, salinity, and nutrient conditions, which together with its complex life history, strong motility, and density-dependent allelopathy, allows it to form blooms that are lethal to almost all marine organisms. However, its toxicity differs between subspecies and some target-species-specific toxicity has also been recorded. Significant gill disorder is observed in affected fish, to which the massive fish kills are attributed, rather than to the hypoxia that occurs in the fading stage of a bloom. However, although this species is haemolytic and cytotoxic, and generates reactive oxygen species, none of the isolated toxins or lipophilic extracts have toxic effects as extreme as those of the intact algal cells. The toxic effects of K. mikimotoi are strongly related to contact with intact cells. Several reasonable hypotheses of how and why this species blooms and causes mass mortalities have been proposed, but further research is required.
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Affiliation(s)
- Xiaodong Li
- Key Laboratory of Marine Biotechnology of Fujian Province, Institute of Oceanology, College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian Province, 350002, China; Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong Province, 266071, China.
| | - Tian Yan
- Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong Province, 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong Province, 266071, China; Centre for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China.
| | - Rencheng Yu
- Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong Province, 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong Province, 266071, China; Centre for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Mingjiang Zhou
- Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong Province, 266071, China
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18
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Wan X, Yao G, Liu Y, Chen J, Jiang H. Research Progress in the Biosynthetic Mechanisms of Marine Polyether Toxins. Mar Drugs 2019; 17:E594. [PMID: 31652489 PMCID: PMC6835853 DOI: 10.3390/md17100594] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 12/28/2022] Open
Abstract
Marine polyether toxins, mainly produced by marine dinoflagellates, are novel, complex, and diverse natural products with extensive toxicological and pharmacological effects. Owing to their harmful effects during outbreaks of marine red tides, as well as their potential value for the development of new drugs, marine polyether toxins have been extensively studied, in terms of toxicology, pharmacology, detection, and analysis, structural identification, as well as their biosynthetic mechanisms. Although the biosynthetic mechanisms of marine polyether toxins are still unclear, certain progress has been made. In this review, research progress and current knowledge on the biosynthetic mechanisms of polyether toxins are summarized, including the mechanisms of carbon skeleton deletion, pendant alkylation, and polyether ring formation, along with providing a summary of mined biosynthesis-related genes. Finally, future research directions and applications of marine polyether toxins are discussed.
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Affiliation(s)
- Xiukun Wan
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China.
| | - Ge Yao
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China.
| | - Yanli Liu
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China.
| | - Jisheng Chen
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China.
| | - Hui Jiang
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China.
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19
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Morlighem JÉRL, Radis-Baptista G. The Place for Enzymes and Biologically Active Peptides from Marine Organisms for Application in Industrial and Pharmaceutical Biotechnology. Curr Protein Pept Sci 2019; 20:334-355. [PMID: 30255754 DOI: 10.2174/1389203719666180926121722] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 09/10/2018] [Accepted: 09/15/2018] [Indexed: 01/07/2023]
Abstract
Since the beginning of written history, diverse texts have reported the use of enzymatic preparations in food processing and have described the medicinal properties of crude and fractionated venoms to treat various diseases and injuries. With the biochemical characterization of enzymes from distinct sources and bioactive polypeptides from animal venoms, the last sixty years have testified the advent of industrial enzymology and protein therapeutics, which are currently applicable in a wide variety of industrial processes, household products, and pharmaceuticals. Bioprospecting of novel biocatalysts and bioactive peptides is propelled by their unsurpassed properties that are applicable for current and future green industrial processes, biotechnology, and biomedicine. The demand for both novel enzymes with desired characteristics and novel peptides that lead to drug development, has experienced a steady increase in response to the expanding global market for industrial enzymes and peptidebased drugs. Moreover, although largely unexplored, oceans and marine realms, with their unique ecosystems inhabited by a large variety of species, including a considerable number of venomous animals, are recognized as untapped reservoirs of molecules and macromolecules (enzymes and bioactive venom-derived peptides) that can potentially be converted into highly valuable biopharmaceutical products. In this review, we have focused on enzymes and animal venom (poly)peptides that are presently in biotechnological use, and considering the state of prospection of marine resources, on the discovery of useful industrial biocatalysts and drug leads with novel structures exhibiting selectivity and improved performance.
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Affiliation(s)
- Jean-Étienne R L Morlighem
- Institute for Marine Sciences, Federal University of Ceara, Av da Abolicao 3207. Fortaleza/CE. 60165081, Brazil
| | - Gandhi Radis-Baptista
- Institute for Marine Sciences, Federal University of Ceara, Av da Abolicao 3207. Fortaleza/CE. 60165081, Brazil
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20
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Wang X, Niu X, Chen Y, Sun Z, Han A, Lou X, Ge J, Li X, Yang Y, Jian J, Gonçalves RJ, Guan W. Transcriptome sequencing of a toxic dinoflagellate, Karenia mikimotoi subjected to stress from solar ultraviolet radiation. HARMFUL ALGAE 2019; 88:101640. [PMID: 31582153 DOI: 10.1016/j.hal.2019.101640] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 06/10/2023]
Abstract
Solar ultraviolet radiation (UVR) is a stress factor in aquatic environments and may act directly or indirectly on orgnisms in the upper layers of the water column. However, UVR effects are usually species-specific and difficult to extrapolate. Here we use the HAB-forming, toxic dinoflagellate Karenia mikimotoi (which was found to be relatively resistant in previous studies) to investigate its transcriptional responses to a one-week UVR exposure. For this, batch cultures of K. mikimotoi were grown with and without UVR, and their transcriptomes (generated via RNAseq technology) were compared. RNA-seq generated 45.31 million reads, which were further assembled to 202600 unigenes (>300bp). Among these, ca. 61% were annotated with NCBI, NR, GO, KOG, PFAM, Swiss-Prot, and KEGG database. Transcriptomic analysis revealed 722 differentially expressed unigenes (DEGs, defined as being within a |log2 fold change| ≥ 2 and padj < 0.05) responding to solar UVR, which were only 0.36% of all unigenes. 716 unigenes were down-regulated, and only 6 unigenes were up-regulated in the UVR compared to non-UVR treatment. KEGG pathway further analysis revealed DEGs were involved in the different pathway; genes involved in the ribosome, endocytosis and steroid biosynthesis pathways were highly down-regulated, but this was not the case for those involved in the energy metabolisms (including photosynthesis, oxidative phosphorylation) which may contribute to the sustainable growth observed in UVR treatment. The up-regulated expression of both zinc-finger proteins (ZFPs) and ribosomal protein L11 (RPL11) may be one of the acclimated mechanisms against UVR. In addition, this work identified down-regulated genes involved in fatty acid degradation and the hydrophobic branched chain amino acids (e.g., Valine, leucine, and isoleucine), which act as structural components of cell membranes modulating lipid homeostasis or turnover. In conclusion, the present study suggests that the toxic dinoflagellate K. mikimotoi has limited transcriptomic regulation but confirms that it appears as a tolerant species in response to solar UVR. These findings expand current knowledge of gene expression in HAB-forming species in response to natural environment factors such as solar radiation.
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Affiliation(s)
- Xinjie Wang
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China; Marine Biology Institute, Shantou University, Shantou, Guangdong 515063 China
| | - Xiaoqin Niu
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Yiji Chen
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Zhewei Sun
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Axiang Han
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Xiayuan Lou
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Jingke Ge
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Xuanwen Li
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Yuqian Yang
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Jianbo Jian
- Marine Biology Institute, Shantou University, Shantou, Guangdong 515063 China
| | - Rodrigo J Gonçalves
- Laboratorio de Oceanografía Biológica (LOBio), Centro para el Estudio de Sistemas Marinos (CESIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). U9120ACD, Puerto Madryn, Argentina
| | - Wanchun Guan
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China.
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21
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Verma A, Kohli GS, Harwood DT, Ralph PJ, Murray SA. Transcriptomic investigation into polyketide toxin synthesis in Ostreopsis (Dinophyceae) species. Environ Microbiol 2019; 21:4196-4211. [PMID: 31415128 DOI: 10.1111/1462-2920.14780] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 08/12/2019] [Accepted: 08/12/2019] [Indexed: 12/01/2022]
Abstract
In marine ecosystems, dinoflagellates can become highly abundant and even dominant at times, despite their comparatively slow growth. Their ecological success may be related to their production of complex toxic polyketide compounds. Ostreopsis species produce potent palytoxin-like compounds (PLTX), which are associated with human skin and eye irritations, and illnesses through the consumption of contaminated seafood. To investigate the genetic basis of PLTX-like compounds, we sequenced and annotated transcriptomes from two PLTX-producing Ostreopsis species; O. cf. ovata, O. cf. siamensis, one non-PLTX producing species, O. rhodesae and compared them to a close phylogenetic relative and non-PLTX producer, Coolia malayensis. We found no clear differences in the presence or diversity of ketosynthase and ketoreductase transcripts between PLTX producing and non-producing Ostreopsis and Coolia species, as both groups contained >90 and > 10 phylogenetically diverse ketosynthase and ketoreductase transcripts, respectively. We report for the first-time type I single-, multi-domain polyketide synthases (PKSs) and hybrid non-ribosomal peptide synthase/PKS transcripts from all species. The long multi-modular PKSs were insufficient by themselves to synthesize the large complex polyether backbone of PLTX-like compounds. This implies that numerous PKS domains, including both single and multi-, work together on the biosynthesis of PLTX-like and other related polyketide compounds.
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Affiliation(s)
- Arjun Verma
- Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales, 2007, Australia
| | - Gurjeet S Kohli
- Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales, 2007, Australia.,Alfred-Wegener-Institute Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, 27515, Germany
| | - D Tim Harwood
- Cawthron Institute, 98, Halifax Street East, Nelson, 7010, New Zealand
| | - Peter J Ralph
- Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales, 2007, Australia
| | - Shauna A Murray
- Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales, 2007, Australia
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22
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Shikata T, Takahashi F, Nishide H, Shigenobu S, Kamei Y, Sakamoto S, Yuasa K, Nishiyama Y, Yamasaki Y, Uchiyama I. RNA-Seq Analysis Reveals Genes Related to Photoreception, Nutrient Uptake, and Toxicity in a Noxious Red-Tide Raphidophyte Chattonella antiqua. Front Microbiol 2019; 10:1764. [PMID: 31417538 PMCID: PMC6685483 DOI: 10.3389/fmicb.2019.01764] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 07/16/2019] [Indexed: 11/13/2022] Open
Abstract
Aquaculture industries are under threat from noxious red tides, but harm can be mitigated by precautions such as early harvesting and restricting fish feeding to just before the outbreak of a red tide. Therefore, accurate techniques for forecasting red-tide outbreaks are strongly needed. Omics analyses have the potential to expand our understanding of the eco-physiology of these organisms at the molecular level, and to facilitate identification of molecular markers for forecasting their population dynamics and occurrence of damages to fisheries. Red tides of marine raphidophytes, especially Chattonella species, often extensively harm aquaculture industries in regions with a temperate climate around the world. A red tide of Chattonella tends to develop just after an input of nutrients along the coast. Chattonella displays diurnal vertical migration regulated by a weak blue light, so it photosynthesizes in the surface layer during the daytime and takes up nutrients in the bottom layer during the nighttime. Superoxide produced by Chattonella cells is a strong candidate for the cause of its toxicity to bacteria and fishes. Here we conducted mRNA-seq of Chattonella antiqua to identify genes with functions closely related to the dynamics of the noxious red tide, such as photosynthesis, photoreception, nutrient uptake, and superoxide production. The genes related to photosynthetic pigment biosynthesis and nutrient uptake had high similarity with those of model organisms of plants and algae and other red-tide microalgae. We identified orthologous genes of photoreceptors such as aureochrome (newly five genes), the cryptochrome/photolyase (CRY/PHR) family (6-4PHR, plant CRY or cyclobutane pyrimidine dimer [CPD] Class III, CPD Class II, and CRY-DASH), and phytochrome (four genes), which regulate various physiological processes such as flagellar motion and cell cycle in model organisms. Six orthologous genes of NADPH oxidase, which produces superoxide on the cell membrane, were found and divided into two types: one with 5–6 transmembrane domains and another with 11 transmembrane domains. The present study should open the way for analyzing the eco-physiological features of marine raphidophytes at the molecular level.
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Affiliation(s)
- Tomoyuki Shikata
- National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research and Education Agency, Hatsukaiti, Japan
| | - Fumio Takahashi
- Department of Biotechnology, College of Life Sciences, Ritsumeikan University, Kusatsu, Japan.,Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology, Kawaguchi, Japan
| | - Hiroyo Nishide
- Laboratory of Genome Informatics, National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Japan
| | - Shuji Shigenobu
- Core Research Facilities, National Institute for Basic Biology, Okazaki, Japan
| | - Yasuhiro Kamei
- Core Research Facilities, National Institute for Basic Biology, Okazaki, Japan
| | - Setsuko Sakamoto
- National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research and Education Agency, Hatsukaiti, Japan
| | - Kouki Yuasa
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Japan
| | - Yoshitaka Nishiyama
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Japan
| | - Yasuhiro Yamasaki
- Laboratory of Environmental Biology, Department of Applied Aquabiology, National Fisheries University, Fisheries Research and Education Agency, Yamaguchi, Japan
| | - Ikuo Uchiyama
- Laboratory of Genome Informatics, National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Japan
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23
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Verma A, Barua A, Ruvindy R, Savela H, Ajani PA, Murray SA. The Genetic Basis of Toxin Biosynthesis in Dinoflagellates. Microorganisms 2019; 7:E222. [PMID: 31362398 PMCID: PMC6722697 DOI: 10.3390/microorganisms7080222] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 07/23/2019] [Accepted: 07/27/2019] [Indexed: 02/07/2023] Open
Abstract
In marine ecosystems, dinoflagellates can become highly abundant and even dominant at times, despite their comparatively slow growth rates. One factor that may play a role in their ecological success is the production of complex secondary metabolite compounds that can have anti-predator, allelopathic, or other toxic effects on marine organisms, and also cause seafood poisoning in humans. Our knowledge about the genes involved in toxin biosynthesis in dinoflagellates is currently limited due to the complex genomic features of these organisms. Most recently, the sequencing of dinoflagellate transcriptomes has provided us with valuable insights into the biosynthesis of polyketide and alkaloid-based toxin molecules in dinoflagellate species. This review synthesizes the recent progress that has been made in understanding the evolution, biosynthetic pathways, and gene regulation in dinoflagellates with the aid of transcriptomic and other molecular genetic tools, and provides a pathway for future studies of dinoflagellates in this exciting omics era.
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Affiliation(s)
- Arjun Verma
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia.
| | - Abanti Barua
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
- Department of Microbiology, Noakhali Science and Technology University, Chittagong 3814, Bangladesh
| | - Rendy Ruvindy
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
| | - Henna Savela
- Finnish Environment Institute, Marine Research Centre, 00790 Helsinki, Finland
| | - Penelope A Ajani
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
| | - Shauna A Murray
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
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24
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Binzer SB, Svenssen DK, Daugbjerg N, Alves-de-Souza C, Pinto E, Hansen PJ, Larsen TO, Varga E. A-, B- and C-type prymnesins are clade specific compounds and chemotaxonomic markers in Prymnesium parvum. HARMFUL ALGAE 2019; 81:10-17. [PMID: 30638493 DOI: 10.1016/j.hal.2018.11.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 11/14/2018] [Accepted: 11/16/2018] [Indexed: 05/11/2023]
Abstract
Harmful blooms formed by planktonic microalgae (HABs) in both freshwater and coastal waters regularly lead to severe mortalities of fish and invertebrates causing substantial economic losses of marine products worldwide. The mixotrophic haptophyte Prymnesium parvum is one of the most important microalgae associated with fish kills. Here 26 strains of P. parvum with a wide geographical distribution were screened for the production of prymnesins, the suspected causative allelochemical toxins. All investigated strains produced prymnesins, indicating that the toxins play an important role for the organism. The prymnesins can be classified into three types based on the length of the carbon backbone of the compound and each algal strain produced only one of these types. Biogeographical mapping of the prymnesin distribution indicated a global distribution of each type. In addition, phylogenetic analyses based on internal transcribed spacer (ITS) sequences revealed monophyletic origin of all prymnesin types and clades could therefore be defined based on the toxic compound. It might be that evolution of new species within the P. parvum species complex is driven by changes in toxin type or that they are a result of it. Such a correlation between chemotype and phylotype has never been documented before for a harmful microalga. Chemotaxonomy and ITS-type classification may thus be used to further delimit the P. parvum species complex.
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Affiliation(s)
- Sofie Bjørnholt Binzer
- Marine Biological Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, 3000, Helsingør, Denmark
| | - Daniel Killerup Svenssen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, 2800, Kgs. Lyngby, Denmark
| | - Niels Daugbjerg
- Marine Biological Section, Department of Biology, University of Copenhagen, Universitetsparken 4, 2200, Copenhagen K, Denmark.
| | - Catharina Alves-de-Souza
- Algal Resources Collection, MARBIONC at CREST Research Park, University of North Carolina Wilmington, 5600 Marvin K. Moss Ln, Wilmington, NC, 28409, USA; Laboratório de Ficologia, Departamento de Botânica, Museu Nacional/Universidade Federal do Rio de Janeiro, Quinta da Boa Vista S/N, São Cristóvão, Rio de Janeiro, RJ, 20940-040, Brazil
| | - Ernani Pinto
- School of Pharmaceutical Sciences, University of Sao Paulo, Av. Prof Lineu Prestes 580, 05508-000, São Paulo, SP, Brazil
| | - Per Juel Hansen
- Marine Biological Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, 3000, Helsingør, Denmark.
| | - Thomas Ostenfeld Larsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, 2800, Kgs. Lyngby, Denmark.
| | - Elisabeth Varga
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, 2800, Kgs. Lyngby, Denmark
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25
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Van Dolah FM, Kohli GS, Morey JS, Murray SA. Both modular and single-domain Type I polyketide synthases are expressed in the brevetoxin-producing dinoflagellate, Karenia brevis (Dinophyceae). JOURNAL OF PHYCOLOGY 2017; 53:1325-1339. [PMID: 28949419 PMCID: PMC5725682 DOI: 10.1111/jpy.12586] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 09/14/2017] [Indexed: 05/09/2023]
Abstract
Dinoflagellates are prolific producers of polyketide compounds, many of which are potent toxins with adverse impacts on human and marine animal health. To identify polyketide synthase (PKS) genes in the brevetoxin-producing dinoflagellate, Karenia brevis, we assembled a transcriptome from 595 million Illumina reads, sampled under different growth conditions. The assembly included 125,687 transcripts greater than 300 nt in length, with over half having >100× coverage. We found 121 transcripts encoding Type I ketosynthase (KS) domains, of which 99 encoded single KS domains, while 22 contained multiple KS domains arranged in 1-3 protein modules. Phylogenetic analysis placed all single domain and a majority of multidomain KSs within a monophyletic clade of protist PKSs. In contrast with the highly amplified single-domain KSs, only eight single-domain ketoreductase transcripts were found in the assembly, suggesting that they are more evolutionarily conserved. The multidomain PKSs were dominated by trans-acyltransferase architectures, which were recently shown to be prevalent in other algal protists. Karenia brevis also expressed several hybrid nonribosomal peptide synthetase (NRPS)/PKS sequences, including a burA-like sequence previously reported in a wide variety of dinoflagellates. This contrasts with a similarly deep transcriptome of Gambierdiscus polynesiensis, which lacked NRPS/PKS other than the burA-like transcript, and may reflect the presence of amide-containing polyketides in K. brevis and their absence from G. polynesiensis. In concert with other recent transcriptome analyses, this study provides evidence for both single domain and multidomain PKSs in the synthesis of polyketide compounds in dinoflagellates.
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Affiliation(s)
- Frances M. Van Dolah
- College of CharlestonSchool of Sciences and Mathematics66 George St.CharlestonSouth Carolina29424USA
- Hollings Marine Laboratory331 Fort Johnson Rd.CharlestonSouth Carolina29412USA
| | - Gurjeet S. Kohli
- Climate Change ClusterUniversity of Technology Sydney15 Broadway, UltimoSydneyNew South Wales2007Australia
- Singapore Centre for Environmental Life Sciences EngineeringNanyang Technological UniversitySingapore689528
| | - Jeanine S. Morey
- Hollings Marine Laboratory331 Fort Johnson Rd.CharlestonSouth Carolina29412USA
- JHT Incorporated2710 Discovery Dr.OrlandoFlorida32826USA
| | - Shauna A. Murray
- Climate Change ClusterUniversity of Technology Sydney15 Broadway, UltimoSydneyNew South Wales2007Australia
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26
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Shmukler YB, Nikishin DA. Ladder-Shaped Ion Channel Ligands: Current State of Knowledge. Mar Drugs 2017; 15:E232. [PMID: 28726749 PMCID: PMC5532674 DOI: 10.3390/md15070232] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 07/07/2017] [Accepted: 07/14/2017] [Indexed: 12/20/2022] Open
Abstract
Ciguatoxins (CTX) and brevetoxins (BTX) are polycyclic ethereal compounds biosynthesized by the worldwide distributed planktonic and epibenthic dinoflagellates of Gambierdiscus and Karenia genera, correspondingly. Ciguatera, evoked by CTXs, is a type of ichthyosarcotoxism, which involves a variety of gastrointestinal and neurological symptoms, while BTXs cause so-called neurotoxic shellfish poisoning. Both types of toxins are reviewed together because of similar mechanisms of their action. These are the only molecules known to activate voltage-sensitive Na⁺-channels in mammals through a specific interaction with site 5 of its α-subunit and may compete for it, which results in an increase in neuronal excitability, neurotransmitter release and impairment of synaptic vesicle recycling. Most marine ciguatoxins potentiate Nav channels, but a considerable number of them, such as gambierol and maitotoxin, have been shown to affect another ion channel. Although the extrinsic function of these toxins is probably associated with the function of a feeding deterrent, it was suggested that their intrinsic function is coupled with the regulation of photosynthesis via light-harvesting complex II and thioredoxin. Antagonistic effects of BTXs and brevenal may provide evidence of their participation as positive and negative regulators of this mechanism.
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Affiliation(s)
- Yuri B Shmukler
- Group of Embryophysiology, N.K. Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 26, Vavilov st, 119334 Moscow, Russia.
| | - Denis A Nikishin
- Group of Embryophysiology, N.K. Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 26, Vavilov st, 119334 Moscow, Russia.
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27
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Kohli GS, Campbell K, John U, Smith KF, Fraga S, Rhodes LL, Murray SA. Role of Modular Polyketide Synthases in the Production of Polyether Ladder Compounds in Ciguatoxin-Producing Gambierdiscus polynesiensis and G. excentricus (Dinophyceae). J Eukaryot Microbiol 2017; 64:691-706. [PMID: 28211202 DOI: 10.1111/jeu.12405] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 01/31/2017] [Accepted: 02/03/2017] [Indexed: 11/28/2022]
Abstract
Gambierdiscus, a benthic dinoflagellate, produces ciguatoxins that cause the human illness Ciguatera. Ciguatoxins are polyether ladder compounds that have a polyketide origin, indicating that polyketide synthases (PKS) are involved in their production. We sequenced transcriptomes of Gambierdiscus excentricus and Gambierdiscus polynesiensis and found 264 contigs encoding single domain ketoacyl synthases (KS; G. excentricus: 106, G. polynesiensis: 143) and ketoreductases (KR; G. excentricus: 7, G. polynesiensis: 8) with sequence similarity to type I PKSs, as reported in other dinoflagellates. In addition, 24 contigs (G. excentricus: 3, G. polynesiensis: 21) encoding multiple PKS domains (forming typical type I PKSs modules) were found. The proposed structure produced by one of these megasynthases resembles a partial carbon backbone of a polyether ladder compound. Seventeen contigs encoding single domain KS, KR, s-malonyltransacylase, dehydratase and enoyl reductase with sequence similarity to type II fatty acid synthases (FAS) in plants were found. Type I PKS and type II FAS genes were distinguished based on the arrangement of domains on the contigs and their sequence similarity and phylogenetic clustering with known PKS/FAS genes in other organisms. This differentiation of PKS and FAS pathways in Gambierdiscus is important, as it will facilitate approaches to investigating toxin biosynthesis pathways in dinoflagellates.
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Affiliation(s)
- Gurjeet S Kohli
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 689528, Singapore
| | - Katrina Campbell
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast, BT9 5AG, United Kingdom
| | - Uwe John
- Alfred-Wegener-Institute Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, 27515, Germany.,Helmholtz Institute for Functional Marine Biodiversity, University of Oldenburg, Oldenburg, 26111, Germany
| | - Kirsty F Smith
- Cawthron Institute, 98 Halifax Street East, Nelson, 7010, New Zealand
| | - Santiago Fraga
- Instituto Español de Oceanografía, Centro Oceanográfico de Vigo, Subida a Radio Faro 50, Vigo, 36390, Spain
| | - Lesley L Rhodes
- Cawthron Institute, 98 Halifax Street East, Nelson, 7010, New Zealand
| | - Shauna A Murray
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia
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