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Meng R, Du X, Ge K, Wu C, Zhang Z, Liang X, Yang J, Zhang H. Does climate change increase the risk of marine toxins? Insights from changing seawater conditions. Arch Toxicol 2024; 98:2743-2762. [PMID: 38795135 DOI: 10.1007/s00204-024-03784-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 05/08/2024] [Indexed: 05/27/2024]
Abstract
Marine toxins produced by marine organisms threaten human health and impose a heavy public health burden on coastal countries. Lately, there has been an emergence of marine toxins in regions that were previously unaffected, and it is believed that climate change may be a significant factor. This paper systematically summarizes the impact of climate change on the risk of marine toxins in terms of changes in seawater conditions. From our findings, climate change can cause ocean warming, acidification, stratification, and sea-level rise. These climatic events can alter the surface temperature, salinity, pH, and nutrient conditions of seawater, which may promote the growth of various algae and bacteria, facilitating the production of marine toxins. On the other hand, climate change may expand the living ranges of marine organisms (such as algae, bacteria, and fish), thereby exacerbating the production and spread of marine toxins. In addition, the sources, distribution, and toxicity of ciguatoxin, tetrodotoxin, cyclic imines, and microcystin were described to improve public awareness of these emerging marine toxins. Looking ahead, developing interdisciplinary cooperation, strengthening monitoring of emerging marine toxins, and exploring more novel approaches are essential to better address the risks of marine toxins posed by climate change. Altogether, the interrelationships between climate, marine ecology, and marine toxins were analyzed in this study, providing a theoretical basis for preventing and managing future health risks from marine toxins.
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Affiliation(s)
- Ruiyang Meng
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Xingde Du
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Kangfeng Ge
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Chunrui Wu
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Zongxin Zhang
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Xiao Liang
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Jun Yang
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Huizhen Zhang
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China.
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2
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Fallon TR, Shende VV, Wierzbicki IH, Pendleton AL, Watervoot NF, Auber RP, Gonzalez DJ, Wisecaver JH, Moore BS. Giant polyketide synthase enzymes in the biosynthesis of giant marine polyether toxins. Science 2024; 385:671-678. [PMID: 39116217 DOI: 10.1126/science.ado3290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 07/10/2024] [Indexed: 08/10/2024]
Abstract
Prymnesium parvum are harmful haptophyte algae that cause massive environmental fish kills. Their polyketide polyether toxins, the prymnesins, are among the largest nonpolymeric compounds in nature and have biosynthetic origins that have remained enigmatic for more than 40 years. In this work, we report the "PKZILLAs," massive P. parvum polyketide synthase (PKS) genes that have evaded previous detection. PKZILLA-1 and -2 encode giant protein products of 4.7 and 3.2 megadaltons that have 140 and 99 enzyme domains. Their predicted polyene product matches the proposed pre-prymnesin precursor of the 90-carbon-backbone A-type prymnesins. We further characterize the variant PKZILLA-B1, which is responsible for the shorter B-type analog prymnesin-B1, from P. parvum RCC3426 and thus establish a general model of haptophyte polyether biosynthetic logic. This work expands expectations of genetic and enzymatic size limits in biology.
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Affiliation(s)
- Timothy R Fallon
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and University of California, San Diego, La Jolla, CA 92093, USA
| | - Vikram V Shende
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and University of California, San Diego, La Jolla, CA 92093, USA
| | - Igor H Wierzbicki
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Amanda L Pendleton
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Nathan F Watervoot
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Robert P Auber
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - David J Gonzalez
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jennifer H Wisecaver
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Bradley S Moore
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and University of California, San Diego, La Jolla, CA 92093, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
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Xu SY, Mo YH, Liu YJ, Wang X, Li HY, Yang WD. Physiological and genetic responses of the benthic dinoflagellate Prorocentrum lima to polystyrene microplastics. HARMFUL ALGAE 2024; 136:102652. [PMID: 38876530 DOI: 10.1016/j.hal.2024.102652] [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: 02/20/2024] [Revised: 05/13/2024] [Accepted: 05/20/2024] [Indexed: 06/16/2024]
Abstract
Microplastics are well known as contaminants in marine environments. With the development of biofilms, most microplastics will eventually sink and deposit in benthic environment. However, little research has been done on benthic toxic dinoflagellates, and the effects of microplastics on benthic dinoflagellates are unknown. Prorocentrum lima is a cosmopolitan toxic benthic dinoflagellate, which can produce a range of polyether metabolites, such as diarrhetic shellfish poisoning (DSP) toxins. In order to explore the impact of microplastics on marine benthic dinoflagellates, in this paper, we studied the effects of polystyrene (PS) on the growth and toxin production of P. lima. The molecular response of P. lima to microplastic stress was analyzed by transcriptomics. We selected 100 nm, 10 μm and 100 μm PS, and set three concentrations of 1 mg L-1, 10 mg L-1 and 100 mg L-1. The results showed that PS exposure had limited effects on cell growth, but increased the OA and extracellular polysaccharide content at high concentrations. After exposure to PS MPs, genes associated with DSP toxins synthesis, carbohydrate synthesis and energy metabolism, such as glycolysis, TCA cycle and pyruvate metabolism, were significantly up-regulated. We speculated that after exposure to microplastics, P. lima may increase the synthesis of DSP toxins and extracellular polysaccharides, improve the level of energy metabolism and gene expression of ABC transporter, thereby protecting algal cells from damage. Our findings provide new insights into the effects of microplastics on toxic benthic dinoflagellates.
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Affiliation(s)
- Si-Yuan Xu
- Key Laboratory of Aquatic Eutrophication and Control of Harmful Algal Blooms of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou 510632, PR China
| | - Yan-Hang Mo
- Key Laboratory of Aquatic Eutrophication and Control of Harmful Algal Blooms of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou 510632, PR China
| | - Yu-Jie Liu
- Key Laboratory of Aquatic Eutrophication and Control of Harmful Algal Blooms of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou 510632, PR China
| | - Xiang Wang
- Key Laboratory of Aquatic Eutrophication and Control of Harmful Algal Blooms of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou 510632, PR China
| | - Hong-Ye Li
- Key Laboratory of Aquatic Eutrophication and Control of Harmful Algal Blooms of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou 510632, PR China
| | - Wei-Dong Yang
- Key Laboratory of Aquatic Eutrophication and Control of Harmful Algal Blooms of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou 510632, PR China.
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Zheng D, Zou L, Zou J, Li Q, Lu S. Refining taxonomic identification of microalgae through molecular and genetic evolution: a case study of Prorocentrum lima and Prorocentrum arenarium. Microbiol Spectr 2024; 12:e0236723. [PMID: 38572997 PMCID: PMC11064606 DOI: 10.1128/spectrum.02367-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 02/08/2024] [Indexed: 04/05/2024] Open
Abstract
Species delimitation based on lineage definition has become increasingly popular. However, these methods have been limited, especially for species that lack genomic data and are morphologically similar. The trickiest part for the species identification is that the interspecific and intraspecific boundaries are vague. Taking Prorocentrum (Dinophyta) as an example, analysis of cell morphology, growth, and toxin synthesis in both species of P. lima and P. arenarium does not provide a reliable basis for species delineation. However, through phylogenetic and genetic distance analyses of their ITS and LSU sequences, establishment of evolutionary tree based on orthologous gene sequences, and combining the results of automatic barcode gap discovery and Poisson tree processes models, it was sustained that P. arenarium does not belong to the P. lima complex and should be considered as an independent species. Interspecies genetic evolution analysis revealed that P. lima and P. arenarium may contribute to evolutionary direction that favors combating reverse environmental factors. In P. lima, viral invasion may be one of the reasons for its large genome size. In the study, P. lima complex has been selected as an example to enhance the taxonomic identification of microalgae through molecular and genetic evolution, offering valuable insights into refining taxonomic identification and promoting microbial biodiversity research in other species.IMPORTANCEMicroalgae, especially the species known as Prorocentrum, have received significant attention due to their ability to trigger harmful algal blooms and produce toxins. However, the boundaries between species and within species are ambiguous. Clear and comprehensive species delineation indicates that Prorocentrum arenarium should be considered as an independent species, separate from the Prorocentrum lima complex. Improving the classification and identification of microalgae through molecular and genetic evolution will provide reference points for other cryptic species. Prorocentrum occupy multiple ecological niches in marine environments, and studying their evolutionary direction contributes to understanding their ecological adaptations and community succession.
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Affiliation(s)
- Danlin Zheng
- College of Life Science and Technology, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Jinan University, Guangzhou, China
| | - Ligong Zou
- College of Life Science and Technology, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Jinan University, Guangzhou, China
| | - Jian Zou
- College of Life Science and Technology, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Jinan University, Guangzhou, China
| | - Qun Li
- College of Life Science and Technology, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Jinan University, Guangzhou, China
| | - Songhui Lu
- College of Life Science and Technology, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Jinan University, Guangzhou, China
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Bui QTN, Pradhan B, Kim HS, Ki JS. Environmental Factors Modulate Saxitoxins (STXs) Production in Toxic Dinoflagellate Alexandrium: An Updated Review of STXs and Synthesis Gene Aspects. Toxins (Basel) 2024; 16:210. [PMID: 38787062 PMCID: PMC11125744 DOI: 10.3390/toxins16050210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/23/2024] [Accepted: 04/28/2024] [Indexed: 05/25/2024] Open
Abstract
The marine dinoflagellate Alexandrium is known to form harmful algal blooms (HABs) and produces saxitoxin (STX) and its derivatives (STXs) that cause paralytic shellfish poisoning (PSP) in humans. Cell growth and cellular metabolism are affected by environmental conditions, including nutrients, temperature, light, and the salinity of aquatic systems. Abiotic factors not only engage in photosynthesis, but also modulate the production of toxic secondary metabolites, such as STXs, in dinoflagellates. STXs production is influenced by a variety of abiotic factors; however, the relationship between the regulation of these abiotic variables and STXs accumulation seems not to be consistent, and sometimes it is controversial. Few studies have suggested that abiotic factors may influence toxicity and STXs-biosynthesis gene (sxt) regulation in toxic Alexandrium, particularly in A. catenella, A. minutum, and A. pacificum. Hence, in this review, we focused on STXs production in toxic Alexandrium with respect to the major abiotic factors, such as temperature, salinity, nutrients, and light intensity. This review informs future research on more sxt genes involved in STXs production in relation to the abiotic factors in toxic dinoflagellates.
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Affiliation(s)
- Quynh Thi Nhu Bui
- Department of Life Science, Sangmyung University, Seoul 03016, Republic of Korea; (Q.T.N.B.); (H.-S.K.)
| | - Biswajita Pradhan
- Department of Biotechnology, Sangmyung University, Seoul 03016, Republic of Korea;
- Department of Botany, Model Degree College, Rayagada 765017, Odisha, India
| | - Han-Sol Kim
- Department of Life Science, Sangmyung University, Seoul 03016, Republic of Korea; (Q.T.N.B.); (H.-S.K.)
| | - Jang-Seu Ki
- Department of Life Science, Sangmyung University, Seoul 03016, Republic of Korea; (Q.T.N.B.); (H.-S.K.)
- Department of Biotechnology, Sangmyung University, Seoul 03016, Republic of Korea;
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Bui QTN, Kim HS, Ki JS. Polyphyletic origin of saxitoxin biosynthesis genes in the marine dinoflagellate Alexandrium revealed by comparative transcriptomics. HARMFUL ALGAE 2024; 134:102620. [PMID: 38705616 DOI: 10.1016/j.hal.2024.102620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/26/2024] [Accepted: 03/15/2024] [Indexed: 05/07/2024]
Abstract
The marine dinoflagellate Alexandrium is known to form harmful algal blooms, and at least 14 species within the genus can produce saxitoxins (STXs). STX biosynthesis genes (sxt) are individually revealed in toxic dinoflagellates; however, the evolutionary history remains controversial. Herein, we determined the transcriptome sequences of toxic Alexandrium (A. catenella and A. pacificum) and non-toxic Alexandrium (A. fraterculus and A. fragae) and characterized their sxt by focusing on evolutionary events and STX production. Comparative transcriptome analysis revealed higher homology of the sxt in toxic Alexandrium than in non-toxic species. Notably, non-toxic Alexandrium spp. were found to have lost two sxt core genes, namely sxtA4 and sxtG. Expression levels of 28 transcripts related to eight sxt core genes showed that sxtA, sxtG, and sxtI were relatively high (>1.5) in the toxic group compared to the non-toxic group. In contrast, the non-toxic group showed high expression levels in sxtU (1.9) and sxtD (1.7). Phylogenetic tree comparisons revealed distinct evolutionary patterns between 28S rDNA and sxtA, sxtB, sxtI, sxtD, and sxtU. However, similar topology was observed between 28S rDNA, sxtS, and sxtH/T. In the sxtB and sxtI phylogeny trees, toxic Alexandrium and cyanobacteria were clustered together, separating from non-toxic species. These suggest that Alexandrium may acquire sxt genes independently via horizontal gene transfer from toxic cyanobacteria and other multiple sources, demonstrating monocistronic transcripts of sxt in dinoflagellates.
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Affiliation(s)
- Quynh Thi Nhu Bui
- Department of Life Science, Sangmyung University, Seoul 03016, South Korea
| | - Han-Sol Kim
- Department of Life Science, Sangmyung University, Seoul 03016, South Korea
| | - Jang-Seu Ki
- Department of Life Science, Sangmyung University, Seoul 03016, South Korea.
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Díaz-Alonso A, Rodríguez F, Riobó P, Álvarez-Salgado X, Teira E, Fernández E. Response of the toxic dinoflagellate Alexandrium minutum to exudates of the eelgrass Zostera marina. HARMFUL ALGAE 2024; 133:102605. [PMID: 38485446 DOI: 10.1016/j.hal.2024.102605] [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: 10/20/2023] [Revised: 01/15/2024] [Accepted: 02/20/2024] [Indexed: 03/19/2024]
Abstract
Biotic interactions are a key factor in the development of harmful algal blooms. Recently, a lower abundance of planktonic dinoflagellates has been reported in areas dominated by seagrass beds, suggesting a negative interaction between both groups of organisms. The interaction between planktonic dinoflagellates and marine phanerogams, as well as the way in which bacteria can affect this interaction, was studied in two experiments using a non-axenic culture of the toxic dinoflagellate Alexandrium minutum exposed to increasing additions of eelgrass (Zostera marina) exudates from old and young leaves and to the presence or absence of antibiotics. In these experiments, A. minutum abundance, growth rate and photosynthetic efficiency (Fv/Fm), as well as bacterial abundance, were measured every 48 h. Toxin concentration per cell was determined at the end of both experiments. Our results demonstrated that Z. marina exudates reduced A. minutum growth rate and, in one of the experiments, also the photosynthetic efficiency. These results are not an indirect effect mediated by the bacteria in the culture, although their growth modify the magnitude of the negative impact on the dinoflagellate growth rate. No clear pattern was observed in the variation of toxin production with the treatments.
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Affiliation(s)
| | - Francisco Rodríguez
- Centro Oceanográfico de Vigo, Instituto Español de Ocanografía, Consejo Superior de Investigaciones Científicas, Spain
| | - Pilar Riobó
- Instituto de Investigacións Mariñas, Consejo Superior de Investigaciones Científicas, Spain
| | - Xose Álvarez-Salgado
- Instituto de Investigacións Mariñas, Consejo Superior de Investigaciones Científicas, Spain
| | - Eva Teira
- Centro de Investigación Mariña, Universidade de Vigo, Vigo, Spain
| | - Emilio Fernández
- Centro de Investigación Mariña, Universidade de Vigo, Vigo, Spain
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Huang D, Cheng CQ, Qiu JB, Huang Y, Zhang HY, Xu ZH, Wu SW, Huang YT, Chen J, Zou LG, Yang WD, Zheng XF, Li HY, Li DW. Mechanistic insights into the effects of diuron exposure on Alexandrium pacificum. WATER RESEARCH 2024; 250:120987. [PMID: 38113594 DOI: 10.1016/j.watres.2023.120987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 12/03/2023] [Accepted: 12/06/2023] [Indexed: 12/21/2023]
Abstract
Diuron (N-(3,4-dichlorophenyl)-N,N‑dimethylurea, DCMU), a ureic herbicide, is extensively used in agriculture to boost crop productivity; however, its extensive application culminates in notable environmental pollution, especially in aquatic habitats. Therefore, the present study investigated the effect of diuron on the dinoflagellate Alexandrium pacificum, which is known to induce harmful algal blooms (HAB), and its potential to biodegrade DCMU. Following a four-day DCMU exposure, our results revealed that A. pacificum proficiently assimilated DCMU at concentrations of 0.05 mg/L and 0.1 mg/L in seawater, attaining a complete reduction (100 % efficiency) after 96 h for both concentrations. Moreover, evaluations of paralytic shellfish toxins content indicated that cells subjected to higher DCMU concentrations (0.1 mg/L) exhibited reductions of 73.4 %, 86.7 %, and 75 % in GTX1, GTX4, and NEO, respectively. Exposure to DCMU led to a notable decrease in A. pacificum's photosynthetic efficacy, accompanied by increased levels of reactive oxygen species (ROS) and suppressed cell growth, with a growth inhibition rate of 41.1 % at 72 h. Proteomic investigations pinpointed the diminished expression levels of specific proteins like SxtV and SxtW, linked to paralytic shellfish toxins (PSTs) synthesis, as well as key proteins associated with Photosystem II, namely PsbA, PsbD, PsbO, and PsbU. Conversely, proteins central to the cysteine biosynthesis pathways exhibited enhanced expression. In summary, our results preliminarily resolved the molecular mechanisms underlying the response of A. pacificum to DCMU and revealed that DCMU affected the synthesis of PSTs. Meanwhile, our data suggested that A. pacificum has great potential in scavenging DCMU.
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Affiliation(s)
- Dan Huang
- Department of Sports Medicine, The First Affiliated Hospital, Guangdong Provincial Key Laboratory of Speed Capability, The Guangzhou Key Laboratory of Precision Orthopedics and Regenerative Medicine, Jinan University, Guangzhou 510630, China
| | - Cai-Qin Cheng
- Department of Sports Medicine, The First Affiliated Hospital, Guangdong Provincial Key Laboratory of Speed Capability, The Guangzhou Key Laboratory of Precision Orthopedics and Regenerative Medicine, Jinan University, Guangzhou 510630, China
| | - Jiang-Bing Qiu
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Yun Huang
- Department of Sports Medicine, The First Affiliated Hospital, Guangdong Provincial Key Laboratory of Speed Capability, The Guangzhou Key Laboratory of Precision Orthopedics and Regenerative Medicine, Jinan University, Guangzhou 510630, China
| | - Hao-Yun Zhang
- Department of Sports Medicine, The First Affiliated Hospital, Guangdong Provincial Key Laboratory of Speed Capability, The Guangzhou Key Laboratory of Precision Orthopedics and Regenerative Medicine, Jinan University, Guangzhou 510630, China
| | - Zhen-Hao Xu
- Department of Sports Medicine, The First Affiliated Hospital, Guangdong Provincial Key Laboratory of Speed Capability, The Guangzhou Key Laboratory of Precision Orthopedics and Regenerative Medicine, Jinan University, Guangzhou 510630, China
| | - Si-Wei Wu
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Yi-Tong Huang
- Department of Sports Medicine, The First Affiliated Hospital, Guangdong Provincial Key Laboratory of Speed Capability, The Guangzhou Key Laboratory of Precision Orthopedics and Regenerative Medicine, Jinan University, Guangzhou 510630, China
| | - Jian Chen
- State Key Laboratory of Medical Vector Surveillance, Zhuhai International Travel Healthcare Center, Zhuhai, Guangdong 519020, China
| | - Li-Gong Zou
- Department of Sports Medicine, The First Affiliated Hospital, Guangdong Provincial Key Laboratory of Speed Capability, The Guangzhou Key Laboratory of Precision Orthopedics and Regenerative Medicine, Jinan University, Guangzhou 510630, China
| | - Wei-Dong Yang
- Department of Sports Medicine, The First Affiliated Hospital, Guangdong Provincial Key Laboratory of Speed Capability, The Guangzhou Key Laboratory of Precision Orthopedics and Regenerative Medicine, Jinan University, Guangzhou 510630, China
| | - Xiao-Fei Zheng
- Department of Sports Medicine, The First Affiliated Hospital, Guangdong Provincial Key Laboratory of Speed Capability, The Guangzhou Key Laboratory of Precision Orthopedics and Regenerative Medicine, Jinan University, Guangzhou 510630, China
| | - Hong-Ye Li
- Department of Sports Medicine, The First Affiliated Hospital, Guangdong Provincial Key Laboratory of Speed Capability, The Guangzhou Key Laboratory of Precision Orthopedics and Regenerative Medicine, Jinan University, Guangzhou 510630, China
| | - Da-Wei Li
- Department of Sports Medicine, The First Affiliated Hospital, Guangdong Provincial Key Laboratory of Speed Capability, The Guangzhou Key Laboratory of Precision Orthopedics and Regenerative Medicine, Jinan University, Guangzhou 510630, China.
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Ly NH, Barceló D, Vasseghian Y, Choo J, Joo SW. Sustainable bioremediation technologies for algal toxins and their ecological significance. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 341:122878. [PMID: 37967713 DOI: 10.1016/j.envpol.2023.122878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 11/01/2023] [Accepted: 11/03/2023] [Indexed: 11/17/2023]
Abstract
The emergence of algal toxins in water ecosystems poses a significant ecological and human health concern. These toxins, produced by various algal species, can lead to harmful algal blooms, and have far-reaching consequences on biodiversity, food chains, and water quality. This review explores the types and sources of algal toxins, their ecological impacts, and the associated human health risks. Additionally, the review delves into the potential of bioremediation strategies to mitigate the effects of algal toxins. It discusses the role of microorganisms, enzymes, and algal-bacterial interactions in toxin removal, along with engineering approaches such as advanced oxidation processes and adsorbent utilization. Microbes and enzymes have been studied for their environmentally friendly and biocompatible properties, which make them useful for controlling or removing harmful algae and their toxins. The challenges and limitations of bioremediation are examined, along with case studies highlighting successful toxin control efforts. Finally, the review outlines future prospects, emerging technologies, and the need for continued research to effectively address the complex issue of algal toxins and their ecological significance.
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Affiliation(s)
- Nguyễn Hoàng Ly
- Department of Chemistry, Gachon University, Seongnam, 13120, Republic of Korea
| | - Damià Barceló
- Water and Soil Quality Research Group, Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 1826, Barcelona, 08034, Spain; Sustainability Cluster, School of Engineering, UPES, Dehradun, 248007, India
| | - Yasser Vasseghian
- Department of Chemistry, Soongsil University, Seoul, 06978, Republic of Korea; School of Engineering, Lebanese American University, Byblos, Lebanon; University Centre for Research & Development, Department of Mechanical Engineering, Chandigarh University, Gharuan, Mohali, Punjab, 140413, India; Department of Sustainable Engineering, Saveetha School of Engineering, SIMATS, Chennai, 602105, India.
| | - Jaebum Choo
- Department of Chemistry, Chung-Ang University, Seoul, 06974, Republic of Korea.
| | - Sang-Woo Joo
- Department of Chemistry, Soongsil University, Seoul, 06978, Republic of Korea.
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10
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Dougan KE, Deng ZL, Wöhlbrand L, Reuse C, Bunk B, Chen Y, Hartlich J, Hiller K, John U, Kalvelage J, Mansky J, Neumann-Schaal M, Overmann J, Petersen J, Sanchez-Garcia S, Schmidt-Hohagen K, Shah S, Spröer C, Sztajer H, Wang H, Bhattacharya D, Rabus R, Jahn D, Chan CX, Wagner-Döbler I. Multi-omics analysis reveals the molecular response to heat stress in a "red tide" dinoflagellate. Genome Biol 2023; 24:265. [PMID: 37996937 PMCID: PMC10666404 DOI: 10.1186/s13059-023-03107-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 11/10/2023] [Indexed: 11/25/2023] Open
Abstract
BACKGROUND "Red tides" are harmful algal blooms caused by dinoflagellate microalgae that accumulate toxins lethal to other organisms, including humans via consumption of contaminated seafood. These algal blooms are driven by a combination of environmental factors including nutrient enrichment, particularly in warm waters, and are increasingly frequent. The molecular, regulatory, and evolutionary mechanisms that underlie the heat stress response in these harmful bloom-forming algal species remain little understood, due in part to the limited genomic resources from dinoflagellates, complicated by the large sizes of genomes, exhibiting features atypical of eukaryotes. RESULTS We present the de novo assembled genome (~ 4.75 Gbp with 85,849 protein-coding genes), transcriptome, proteome, and metabolome from Prorocentrum cordatum, a globally abundant, bloom-forming dinoflagellate. Using axenic algal cultures, we study the molecular mechanisms that underpin the algal response to heat stress, which is relevant to current ocean warming trends. We present the first evidence of a complementary interplay between RNA editing and exon usage that regulates the expression and functional diversity of biomolecules, reflected by reduction in photosynthesis, central metabolism, and protein synthesis. These results reveal genomic signatures and post-transcriptional regulation for the first time in a pelagic dinoflagellate. CONCLUSIONS Our multi-omics analyses uncover the molecular response to heat stress in an important bloom-forming algal species, which is driven by complex gene structures in a large, high-G+C genome, combined with multi-level transcriptional regulation. The dynamics and interplay of molecular regulatory mechanisms may explain in part how dinoflagellates diversified to become some of the most ecologically successful organisms on Earth.
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Affiliation(s)
- Katherine E Dougan
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Zhi-Luo Deng
- Helmholtz-Center for Infection Research (HZI), Inhoffenstraße 7, Braunschweig, 38124, Germany
| | - Lars Wöhlbrand
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, 26129, Oldenburg, Germany
| | - Carsten Reuse
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Boyke Bunk
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Yibi Chen
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Juliane Hartlich
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Karsten Hiller
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Uwe John
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany
- Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Ammerländer Heerstraße 231, 26129, Oldenburg, Germany
| | - Jana Kalvelage
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, 26129, Oldenburg, Germany
| | - Johannes Mansky
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Meina Neumann-Schaal
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Jörg Overmann
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Jörn Petersen
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Selene Sanchez-Garcia
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Kerstin Schmidt-Hohagen
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Sarah Shah
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Cathrin Spröer
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Helena Sztajer
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Hui Wang
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Ralf Rabus
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, 26129, Oldenburg, Germany
| | - Dieter Jahn
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Cheong Xin Chan
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia.
| | - Irene Wagner-Döbler
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany.
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11
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Abassi S, Kim HS, Bui QTN, Ki JS. Effects of nitrate on the saxitoxins biosynthesis revealed by sxt genes in the toxic dinoflagellate Alexandrium pacificum (group IV). HARMFUL ALGAE 2023; 127:102473. [PMID: 37544673 DOI: 10.1016/j.hal.2023.102473] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 06/09/2023] [Accepted: 06/10/2023] [Indexed: 08/08/2023]
Abstract
The dinoflagellate Alexandrium pacificum (group IV) is of particular interest because of its involvement in harmful algal blooms and production of saxitoxin (STX), which causes paralytic shellfish poisoning. The toxicity from STX and its analogues (STXs) is suspected to be affected by nitrogen (N) availability. However, the toxicity-associated behavior and STX-biosynthesis gene responses of the toxic A. pacificum under N fluctuations have not been sufficiently investigated. In the present study, we identified the sxtI gene involved in sxt biosynthesis pathway and evaluated the effects of nitrate (NO3-) on STXs production and the expression of four sxt core genes (sxtA4, sxtG, sxtB, and sxtI). Quantification of total STXs levels in the cultures under different NO3- regimes showed that NO3- concentration influenced STXs production. In addition, the proportion and concentration of STXs varied depending on the NO3- concentration. Core sxt transcript abundance was also influenced by available NO3- in a time-dependent manner. Expressional levels and patterns of sxtI were correlated with those of sxtA and sxtB. The relationship between the toxins and sxt responses in A. pacificum under various NO3- regimes suggests the direct involvement of N in the STXs biosynthesis pathway. Understanding this link would provide a tool to understand the toxin dynamics of dinoflagellates following N shifts in marine environments.
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Affiliation(s)
- Sofia Abassi
- Department of Biotechnology, Sangmyung University, Seoul, 03016, Republic of Korea
| | - Han-Sol Kim
- Department of Biotechnology, Sangmyung University, Seoul, 03016, Republic of Korea
| | - Quynh Thi Nhu Bui
- Department of Biotechnology, Sangmyung University, Seoul, 03016, Republic of Korea
| | - Jang-Seu Ki
- Department of Biotechnology, Sangmyung University, Seoul, 03016, Republic of Korea.
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12
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Kim HS, Park H, Wang H, Kim T, Ki JS. Saxitoxins-producing potential of the marine dinoflagellate Alexandrium affine and its environmental implications revealed by toxins and transcriptome profiling. MARINE ENVIRONMENTAL RESEARCH 2023; 185:105874. [PMID: 36689843 DOI: 10.1016/j.marenvres.2023.105874] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/08/2022] [Accepted: 01/04/2023] [Indexed: 06/17/2023]
Abstract
The marine dinoflagellate Alexandrium occurs widely in coastal waters, and some of them can produce saxitoxins (STXs) that cause paralytic shellfish poisoning (PSP). Alexandrium affine is a harmful algal bloom (HAB)-forming species off the coast of Asia; however, its ability to produce STXs has been controversial. In the present study, we detected STXs in A. affine Alex02 isolated from the southern coast of Korea. The total STXs equivalent (STXs eq) and profiles of Alex02 varied depending on the tested environmental conditions, including the temperature and nitrate concentrations. STXs toxicity levels of A. affine Alex02 (<0.8 STXs eq fmol cell-1) were significantly lower than those of toxic A. catenella Alex03 and A. pacificum Alex05. On a genetic basis, we identified all the STX biosynthesis sxt genes, except sxtX in A. affine, via large-scale transcriptome analysis. Interestingly, the two proteins, sxtA4 and sxtG, were similar in sequence and domain structure to those of other toxic dinoflagellates and cyanobacteria; however, their transcript levels were extremely low. Our results suggest that A. affine has the potential to produce STXs, while its toxicity is much lower or negligible, which is unlikely to cause PSP incidents in marine environments.
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Affiliation(s)
- Han-Sol Kim
- Department of Biotechnology, Sangmyung University, Seoul, 03016, South Korea
| | - Hyunjun Park
- Department of Biotechnology, Sangmyung University, Seoul, 03016, South Korea
| | - Hui Wang
- Department of Biotechnology, Sangmyung University, Seoul, 03016, South Korea
| | - Taehee 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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13
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Verma A, Hoppenrath M, Smith KF, Murray JS, Harwood DT, Hosking JM, Rongo T, Rhodes LL, Murray SA. Ostreopsis Schmidt and Coolia Meunier (Dinophyceae, Gonyaulacales) from Cook Islands and Niue (South Pacific Ocean), including description of Ostreopsis tairoto sp. nov. Sci Rep 2023; 13:3110. [PMID: 36813881 PMCID: PMC9947023 DOI: 10.1038/s41598-023-29969-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 02/14/2023] [Indexed: 02/24/2023] Open
Abstract
It is important to decipher the diversity and distribution of benthic dinoflagellates, as there are many morphologically indistinct taxa that differ from one another in production of potent toxins. To date, the genus Ostreopsis comprises twelve described species, of which seven are potentially toxic and produce compounds presenting a threat to human and environmental health. In this study, isolates previously identified as "Ostreopsis sp. 3" were sampled from the area where it was first reported, Rarotonga, Cook Islands, and have been taxonomically and phylogenetically characterised as Ostreopsis tairoto sp. nov. Phylogenetically, the species is closely related to "Ostreopsis sp. 8", O. mascarenensis, "O. sp. 4", O. fattorussoi, O. rhodesiae and O. cf. siamensis. Previously, it was considered a part of the O. cf. ovata complex but can be distinguished from O. cf. ovata based on the small pores identified on this study, and from O. fattorussoi and O. rhodesiae based on relative lengths of the 2' plates. No known palytoxin -like compounds were detected in strains investigated in this study. Strains of O. lenticularis, Coolia malayensis and C. tropicalis were also identified and described. This study advances our knowledge of biogeography, distribution, and toxins of Ostreopsis and Coolia species.
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Affiliation(s)
- A. Verma
- grid.117476.20000 0004 1936 7611School of Life Sciences, University of Technology, Broadway, Sydney, NSW 2007 Australia
| | - M. Hoppenrath
- grid.500026.10000 0004 0487 6958Senckenberg am Meer, German Center for Marine Biodiversity Research (DZMB), Südstrand 44, D-26382 Wilhelmshaven, Germany
| | - K. F. Smith
- grid.418703.90000 0001 0740 4700Cawthron Institute, Nelson, 7010 New Zealand
| | - J. S. Murray
- grid.418703.90000 0001 0740 4700Cawthron Institute, Nelson, 7010 New Zealand
| | - D. T. Harwood
- grid.418703.90000 0001 0740 4700Cawthron Institute, Nelson, 7010 New Zealand
| | - J. M. Hosking
- Te Ipukarea Society, PO Box 649, Rarotonga, Cook Islands
| | - T. Rongo
- Kōrero O Te `Ōrau, Avarua, PO Box 881, Avarua, Rarotonga, Cook Islands
| | - L. L. Rhodes
- grid.418703.90000 0001 0740 4700Cawthron Institute, Nelson, 7010 New Zealand
| | - S. A. Murray
- grid.117476.20000 0004 1936 7611School of Life Sciences, University of Technology, Broadway, Sydney, NSW 2007 Australia
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14
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Mashini AG, Oakley CA, Beepat SS, Peng L, Grossman AR, Weis VM, Davy SK. The Influence of Symbiosis on the Proteome of the Exaiptasia Endosymbiont Breviolum minutum. Microorganisms 2023; 11:292. [PMID: 36838257 PMCID: PMC9967746 DOI: 10.3390/microorganisms11020292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/13/2023] [Accepted: 01/19/2023] [Indexed: 01/26/2023] Open
Abstract
The cellular mechanisms responsible for the regulation of nutrient exchange, immune response, and symbiont population growth in the cnidarian-dinoflagellate symbiosis are poorly resolved. Here, we employed liquid chromatography-mass spectrometry to elucidate proteomic changes associated with symbiosis in Breviolum minutum, a native symbiont of the sea anemone Exaiptasia diaphana ('Aiptasia'). We manipulated nutrients available to the algae in culture and to the holobiont in hospite (i.e., in symbiosis) and then monitored the impacts of our treatments on host-endosymbiont interactions. Both the symbiotic and nutritional states had significant impacts on the B. minutum proteome. B. minutum in hospite showed an increased abundance of proteins involved in phosphoinositol metabolism (e.g., glycerophosphoinositol permease 1 and phosphatidylinositol phosphatase) relative to the free-living alga, potentially reflecting inter-partner signalling that promotes the stability of the symbiosis. Proteins potentially involved in concentrating and fixing inorganic carbon (e.g., carbonic anhydrase, V-type ATPase) and in the assimilation of nitrogen (e.g., glutamine synthase) were more abundant in free-living B. minutum than in hospite, possibly due to host-facilitated access to inorganic carbon and nitrogen limitation by the host when in hospite. Photosystem proteins increased in abundance at high nutrient levels irrespective of the symbiotic state, as did proteins involved in antioxidant defences (e.g., superoxide dismutase, glutathione s-transferase). Proteins involved in iron metabolism were also affected by the nutritional state, with an increased iron demand and uptake under low nutrient treatments. These results detail the changes in symbiont physiology in response to the host microenvironment and nutrient availability and indicate potential symbiont-driven mechanisms that regulate the cnidarian-dinoflagellate symbiosis.
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Affiliation(s)
| | - Clinton A. Oakley
- School of Biological Sciences, Victoria University of Wellington, Wellington 6140, New Zealand
| | - Sandeep S. Beepat
- School of Biological Sciences, Victoria University of Wellington, Wellington 6140, New Zealand
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Lifeng Peng
- School of Biological Sciences, Victoria University of Wellington, Wellington 6140, New Zealand
- Centre for Biodiscovery, Victoria University of Wellington, Wellington 6140, New Zealand
| | - Arthur R. Grossman
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Virginia M. Weis
- Department of Integrative Biology, Oregon State University, Corvallis, OR 97331, USA
| | - Simon K. Davy
- School of Biological Sciences, Victoria University of Wellington, Wellington 6140, New Zealand
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15
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Mary L, Quere J, Latimier M, Rovillon GA, Hégaret H, Réveillon D, Le Gac M. Genetic association of toxin production in the dinoflagellate Alexandrium minutum. Microb Genom 2022; 8:mgen000879. [PMID: 36326655 PMCID: PMC9836089 DOI: 10.1099/mgen.0.000879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 07/25/2022] [Indexed: 11/06/2022] Open
Abstract
Dinoflagellates of the genus Alexandrium are responsible for harmful algal blooms and produce paralytic shellfish toxins (PSTs). Their very large and complex genomes make it challenging to identify the genes responsible for toxin synthesis. A family-based genomic association study was developed to determine the inheritance of toxin production in Alexandrium minutum and identify genomic regions linked to this production. We show that the ability to produce toxins is inheritable in a Mendelian way, while the heritability of the toxin profile is more complex. We developed the first dinoflagellate genetic linkage map. Using this map, several major results were obtained: 1. A genomic region related to the ability to produce toxins was identified. 2. This region does not contain any polymorphic sxt genes, known to be involved in toxin production in cyanobacteria. 3. The sxt genes, known to be present in a single cluster in cyanobacteria, are scattered on different linkage groups in A. minutum. 4. The expression of two sxt genes not assigned to any linkage group, sxtI and sxtG, may be regulated by the genomic region related to the ability to produce toxins. Our results provide new insights into the organization of toxicity-related genes in A. minutum, suggesting a dissociated genetic mechanism for the production of the different analogues and the ability to produce toxins. However, most of the newly identified genes remain unannotated. This study therefore proposes new candidate genes to be further explored to understand how dinoflagellates synthesize their toxins.
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Affiliation(s)
- Lou Mary
- Ifremer, DYNECO PELAGOS, 29280 Plouzané, France
- Ifremer, PHYTOX, Laboratoire METALG, F-44000 Nantes, France
- Laboratoire des Sciences de l’Environnement Marin (LEMAR), UMR 6539 CNRS UBO IRD IFREMER - Institut Universitaire Européen de la Mer, 29280 Plouzané, France
| | | | | | | | - Hélène Hégaret
- Laboratoire des Sciences de l’Environnement Marin (LEMAR), UMR 6539 CNRS UBO IRD IFREMER - Institut Universitaire Européen de la Mer, 29280 Plouzané, France
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16
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Judd M, Place AR. A Strategy for Gene Knockdown in Dinoflagellates. Microorganisms 2022; 10:microorganisms10061131. [PMID: 35744649 PMCID: PMC9228228 DOI: 10.3390/microorganisms10061131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 02/01/2023] Open
Abstract
Dinoflagellates are unicellular protists that display unusual nuclear features such as large genomes, condensed chromosomes and multiple gene copies organized as tandem gene arrays. Genetic regulation is believed to be controlled at the translational rather than transcriptional level. An important player in this process is initiation factor eIF4E which binds the 7-methylguanosine cap structure (m7G) at the 5′-end of mRNA. Transcriptome analysis of eleven dinoflagellate species has established that each species encodes between eight to fifteen eIF4E family members. Determining the role of eIF4E family members in gene expression requires a method of knocking down their expression. In other eukaryotes this can be accomplished using translational blocking morpholinos that bind to complementary strands of RNA, therefore inhibiting the mRNA processing. Previously, unmodified morpholinos lacked the ability to pass through cell membranes, however peptide-based reagents have been used to deliver substances into the cytosol of cells by an endocytosis-mediated process without damaging the cell membrane. We have successfully delivered fluorescently-tagged morpholinos to the cytosol of Amphidinium carterae by using a specific cell penetrating peptide with the goal to target an eIF4e-1a sequence to inhibit translation. Specific eIF4e knockdown success (up to 42%) has been characterized via microscopy and western blot analysis.
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17
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Alzheimer’s Disease and Toxins Produced by Marine Dinoflagellates: An Issue to Explore. Mar Drugs 2022; 20:md20040253. [PMID: 35447926 PMCID: PMC9029327 DOI: 10.3390/md20040253] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/21/2022] [Accepted: 03/30/2022] [Indexed: 12/10/2022] Open
Abstract
This paper examined the toxins naturally produced by marine dinoflagellates and their effects on increases in β-amyloid plaques along with tau protein hyperphosphorylation, both major drivers of Alzheimer’s disease (AD). This approach is in line with the demand for certain natural compounds, namely those produced by marine invertebrates that have the potential to be used in the treatment of AD. Current advances in AD treatment are discussed as well as the main factors that potentially affect the puzzling global AD pattern. This study focused on yessotoxins (YTXs), gymnodimine (GYM), spirolides (SPXs), and gambierol, all toxins that have been shown to reduce β-amyloid plaques and tau hyperphosphorylation, thus preventing the neuronal or synaptic dysfunction that ultimately causes the cell death associated with AD (or other neurodegenerative diseases). Another group of toxins described, okadaic acid (OA) and its derivatives, inhibit protein phosphatase activity, which facilitates the presence of phosphorylated tau proteins. A few studies have used OA to trigger AD in zebrafish, providing an opportunity to test in vivo the effectiveness of new drugs in treating or attenuating AD. Constraints on the production of marine toxins for use in these tests have been considered. Different lines of research are anticipated regarding the action of the two groups of toxins.
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18
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Dinoflagellate Phosphopantetheinyl Transferase (PPTase) and Thiolation Domain Interactions Characterized Using a Modified Indigoidine Synthesizing Reporter. Microorganisms 2022; 10:microorganisms10040687. [PMID: 35456738 PMCID: PMC9027781 DOI: 10.3390/microorganisms10040687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/07/2022] [Accepted: 03/14/2022] [Indexed: 02/01/2023] Open
Abstract
Photosynthetic dinoflagellates synthesize many toxic but also potential therapeutic compounds therapeutics via polyketide/non-ribosomal peptide synthesis, a common means of producing natural products in bacteria and fungi. Although canonical genes are identifiable in dinoflagellate transcriptomes, the biosynthetic pathways are obfuscated by high copy numbers and fractured synteny. This study focuses on the carrier domains that scaffold natural product synthesis (thiolation domains) and the phosphopantetheinyl transferases (PPTases) that thiolate these carriers. We replaced the thiolation domain of the indigoidine producing BpsA gene from Streptomyces lavendulae with those of three multidomain dinoflagellate transcripts and coexpressed these constructs with each of three dinoflagellate PPTases looking for specific pairings that would identify distinct pathways. Surprisingly, all three PPTases were able to activate all the thiolation domains from one transcript, although with differing levels of indigoidine produced, demonstrating an unusual lack of specificity. Unfortunately, constructs with the remaining thiolation domains produced almost no indigoidine and the thiolation domain for lipid synthesis could not be expressed in E. coli. These results combined with inconsistent protein expression for different PPTase/thiolation domain pairings present technical hurdles for future work. Despite these challenges, expression of catalytically active dinoflagellate proteins in E. coli is a novel and useful tool going forward.
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Thi Nhu Bui Q, Kim H, Wang H, Ki JS. Unveiling the genomic structures and evolutionary events of the saxitoxin biosynthetic gene sxtA in the marine toxic dinoflagellate Alexandrium. Mol Phylogenet Evol 2022; 168:107417. [PMID: 35031458 DOI: 10.1016/j.ympev.2022.107417] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 11/24/2021] [Accepted: 12/27/2021] [Indexed: 12/30/2022]
Abstract
Marine dinoflagellates Alexandriumare known to produce saxitoxin (STX) and cause paralytic shellfish poisoning (PSP) which can result in mortality in human. SxtA is considered a core gene for the biosynthesis of STX. However, its gene coding structure and evolutionary history have yet to be fully elucidated. Here, we determined the full-length sequences of sxtA cDNA and genomic coding regions from two toxic dinoflagellates, Alexandrium catenella (LIMS-PS-2645 and LIMS-PS-2647) andA. pacificum (LMBE-C4), characterised their domain structures, and resolved evolutionary events. The sxtA gene was encoded on the genome without introns, and was identical in length (4002 bp) between two A. catenella strains, but their sequences differed from A. pacificum (5031 bp). SxtA consists of four domains, sxtA1, sxtA2, sxtA3, and sxtA4; however, A. pacificum has an extra domain TauD near sxtA1. Each domain had >64.4% GC content, with the highest being 71.6% in sxtA3. Molecular divergence was found to be significantly higher in sxtA4 than in the other domains. Phylogenetic trees of sxtA and separate domains showed that bacteria diverged earliest, followed by non-toxic, toxic cyanobacteria, toxic dinoflagellates. While sxtA domains in Alexandrium were similar to the PKS-like structure with the conserved sxtA1, sxtA2, and sxtA3. PKS_KS may be replaced by sxtA4 in toxic Alexandrium. These suggest that sxtA in Alexandrium may have evolved by acquiring specific domains, whose modification and complexity markedly affect toxin biosynthesis.
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Affiliation(s)
- Quynh Thi Nhu Bui
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea
| | - Hansol Kim
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea
| | - Hui Wang
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea; Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, University of South China, Hengyang 421001, China
| | - Jang-Seu Ki
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea.
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Wang H, Kim H, Park H, Ki JS. Temperature influences the content and biosynthesis gene expression of saxitoxins (STXs) in the toxigenic dinoflagellate Alexandrium pacificum. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 802:149801. [PMID: 34454155 DOI: 10.1016/j.scitotenv.2021.149801] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Temperature may affect the production of saxitoxin (STX) and its derivatives (STXs); however, this is still controversial. Further, STX-biosynthesis gene regulation and the relation of its toxicity with temperature are not clearly understood. In the present study, we evaluated the effects of different temperatures (12 °C, 16 °C, and 20 °C) on the growth, toxin profiles, and expression of two core STX-biosynthesis genes, sxtA and sxtG, in the toxic dinoflagellate Alexandrium pacificum Alex05, isolated from Korean coasts. We found that temperature significantly affected cell growth, with maximum growth recorded at 16 °C, followed by 20 °C and 12 °C. HPLC analysis revealed mostly 12 of STXs from the tested cultures. Interestingly, the contents of STXs increased in the cells cultured at 16 °C and exposed to cold stress, compared to the 20 °C culture and heat stress; however, toxin components were much more diverse under heat stress. These toxin profiles generally matched with the sxtA and sxtG expression levels. Incubation at lower temperatures (12 °C and 16 °C) and exposure to cold stress increased sxtA and sxtG expressions in the cells, whereas heat stress showed little change or downregulated the transcription of both genes. Principal component analysis (PCA) showed low correlation between STXs eq and expressional levels of sxtA and sxtG in heat-stressed cells. These results suggest that temperature might be a crucial factor affecting the level and biosynthesis of STXs in marine toxic dinoflagellates.
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Affiliation(s)
- Hui Wang
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea; Hunan Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, China
| | - Hansol Kim
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea
| | - Hyunjun Park
- 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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21
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Sandoval-Sanhueza A, Aguilera-Belmonte A, Basti L, Figueroa RI, Molinet C, Álvarez G, Oyanedel S, Riobó P, Mancilla-Gutiérrez G, Díaz PA. Interactive effects of temperature and salinity on the growth and cytotoxicity of the fish-killing microalgal species Heterosigma akashiwo and Pseudochattonella verruculosa. MARINE POLLUTION BULLETIN 2022; 174:113234. [PMID: 34922228 DOI: 10.1016/j.marpolbul.2021.113234] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
Fish-killing blooms of Heterosigma akashiwo and Pseudochattonella verruculosa have been devastating for the farmed salmon industry, but in Southern Chile the conditions that promote the growth and toxicity of these microalgae are poorly understood. This study examined the effects of different combinations of temperature (12, 15, 18 °C) and salinity (10, 20, 30 psu) on the growth of Chilean strains of these two species. The results showed that the optimal growth conditions for H. akashiwo and P. verruculosa differed, with a maximum rate of 0.99 day-1 obtained at 15 °C and a salinity of 20 psu for H. akashiwo, and a maximum rate of 1.06 day-1 obtained at 18 °C and a salinity of 30 psu for P. verruculosa. Cytotoxic assays (2 × 101 - 2 × 105 cell mL-1; cells, filtrates, and cell lysates) performed at salinities of 20 and 30 psu showed a 100% reduction in the viability of embryonic fish cells exposed to intact cells of H. akashiwo and a 39% reduction following exposure to culture filtrates of P. verruculosa. Differences in the fish-killing mechanisms (direct cell contact vs. extracellular substances) and physiological traits of H. akashiwo and P. verruculosa explain the recent occurrence of very large blooms under contrasting (cold-brackish vs. hot-salty) extreme climate conditions in Chile.
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Affiliation(s)
| | - Alejandra Aguilera-Belmonte
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Lago Panguipulli 1390, Puerto Montt 5501842, Chile
| | - Leila Basti
- Faculty of Marine Environment and Resources, Tokyo University of Marine Science and Technology, 108-8477 Tokyo, Japan
| | - Rosa I Figueroa
- Centro Oceanográfico de Vigo, Instituto Español de Oceanografía (IEO-CSIC), Subida a Radio Faro 50, 36390 Vigo, Spain
| | - Carlos Molinet
- Programa de Investigación Pesquera, Instituto de Acuicultura, Universidad Austral de Chile, Puerto Montt, Chile; Programa Integrativo, Centro Interdisciplinario para la Investigación Acuícola (INCAR), Universidad de Concepción, Chile
| | - Gonzalo Álvarez
- Facultad de Ciencias del Mar, Departamento de Acuicultura, Universidad Católica del Norte, Coquimbo, Chile; Centro de Investigación y Desarrollo Tecnológico en Algas (CIDTA), Facultad de Ciencias del Mar, Larrondo 1281, Universidad Católica del Norte, Coquimbo, Chile
| | - Sandra Oyanedel
- Fraunhofer Chile Research - Fundación Chile, Quillaipe Aquaculture Center, Km 23.8 Quillaipe, Puerto Montt, Chile
| | - Pilar Riobó
- Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas (IIM-CSIC), 36208 Vigo, Spain
| | | | - Patricio A Díaz
- Centro i~mar, Universidad de Los Lagos, Casilla 557, Puerto Montt, Chile; CeBiB, Universidad de Los Lagos, Casilla 557, Puerto Montt, Chile.
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22
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Latitudinal Variation in the Toxicity and Sexual Compatibility of Alexandrium catenella Strains from Southern Chile. Toxins (Basel) 2021; 13:toxins13120900. [PMID: 34941737 PMCID: PMC8706904 DOI: 10.3390/toxins13120900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/04/2021] [Accepted: 12/07/2021] [Indexed: 12/13/2022] Open
Abstract
The bloom-forming toxic dinoflagellate Alexandrium catenella was first detected in southern Chile (39.5–55° S) 50 years ago and is responsible for most of the area’s cases of paralytic shellfish poisoning (PSP). Given the complex life history of A. catenella, which includes benthic sexual cysts, in this study, we examined the potential link between latitude, toxicity, and sexual compatibility. Nine clones isolated from Chilean Patagonia were used in self- and out-crosses in all possible combinations (n = 45). The effect of latitude on toxicity, reproductive success indexes, and cyst production was also determined. Using the toxin profiles for all strains, consisting of C1, C2, GTX4, GTX1, GTX3, and NeoSTX, a latitudinal gradient was determined for their proportions (%) and content per cell (pg cell−1), with the more toxic strains occurring in the north (−40.6° S). Reproductive success also showed a latitudinal tendency and was lower in the north. None of the self-crosses yielded resting cysts. Rather, the production of resting cysts was highest in pairings of clones separated by distances of 1000–1650 km. Our results contribute to a better understanding of PSP outbreaks in the region and demonstrate the importance of resting cysts in fueling new toxic events. They also provide additional evidence that the introduction of strains from neighboring regions is a cause for concern.
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Dean KJ, Alexander RP, Hatfield RG, Lewis AM, Coates LN, Collin T, Teixeira Alves M, Lee V, Daumich C, Hicks R, White P, Thomas KM, Ellis JR, Turner AD. The Common Sunstar Crossaster papposus-A Neurotoxic Starfish. Mar Drugs 2021; 19:695. [PMID: 34940694 PMCID: PMC8704474 DOI: 10.3390/md19120695] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/01/2021] [Accepted: 12/01/2021] [Indexed: 12/21/2022] Open
Abstract
Saxitoxins (STXs) are a family of potent neurotoxins produced naturally by certain species of phytoplankton and cyanobacteria which are extremely toxic to mammalian nervous systems. The accumulation of STXs in bivalve molluscs can significantly impact animal and human health. Recent work conducted in the North Sea highlighted the widespread presence of various saxitoxins in a range of benthic organisms, with the common sunstar (Crossaster papposus) demonstrating high concentrations of saxitoxins. In this study, an extensive sampling program was undertaken across multiple seas surrounding the UK, with 146 starfish and 5 brittlestars of multiple species analysed for STXs. All the common sunstars analysed (n > 70) contained quantifiable levels of STXs, with the total concentrations ranging from 99 to 11,245 µg STX eq/kg. The common sunstars were statistically different in terms of toxin loading to all the other starfish species tested. Two distinct toxic profiles were observed in sunstars, a decarbomylsaxitoxin (dcSTX)-dominant profile which encompassed samples from most of the UK coast and an STX and gonyautoxin2 (GTX2) profile from the North Yorkshire coast of England. Compartmentalisation studies demonstrated that the female gonads exhibited the highest toxin concentrations of all the individual organs tested, with concentrations >40,000 µg STX eq/kg in one sample. All the sunstars, male or female, exhibited the presence of STXs in the skin, digestive glands and gonads. This study highlights that the common sunstar ubiquitously contains STXs, independent of the geographical location around the UK and often at concentrations many times higher than the current regulatory limits for STXs in molluscs; therefore, the common sunstar should be considered toxic hereafter.
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Affiliation(s)
- Karl J. Dean
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Barrack Road, Weymouth DT4 8UB, UK; (R.P.A.); (R.G.H.); (A.M.L.); (L.N.C.); (T.C.); (M.T.A.); (V.L.); (C.D.); (R.H.); (P.W.); (A.D.T.)
| | - Ryan P. Alexander
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Barrack Road, Weymouth DT4 8UB, UK; (R.P.A.); (R.G.H.); (A.M.L.); (L.N.C.); (T.C.); (M.T.A.); (V.L.); (C.D.); (R.H.); (P.W.); (A.D.T.)
| | - Robert G. Hatfield
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Barrack Road, Weymouth DT4 8UB, UK; (R.P.A.); (R.G.H.); (A.M.L.); (L.N.C.); (T.C.); (M.T.A.); (V.L.); (C.D.); (R.H.); (P.W.); (A.D.T.)
| | - Adam M. Lewis
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Barrack Road, Weymouth DT4 8UB, UK; (R.P.A.); (R.G.H.); (A.M.L.); (L.N.C.); (T.C.); (M.T.A.); (V.L.); (C.D.); (R.H.); (P.W.); (A.D.T.)
| | - Lewis N. Coates
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Barrack Road, Weymouth DT4 8UB, UK; (R.P.A.); (R.G.H.); (A.M.L.); (L.N.C.); (T.C.); (M.T.A.); (V.L.); (C.D.); (R.H.); (P.W.); (A.D.T.)
| | - Tom Collin
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Barrack Road, Weymouth DT4 8UB, UK; (R.P.A.); (R.G.H.); (A.M.L.); (L.N.C.); (T.C.); (M.T.A.); (V.L.); (C.D.); (R.H.); (P.W.); (A.D.T.)
- Department of Chemistry, University of Surrey, Guildford GU2 7XH, UK
| | - Mickael Teixeira Alves
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Barrack Road, Weymouth DT4 8UB, UK; (R.P.A.); (R.G.H.); (A.M.L.); (L.N.C.); (T.C.); (M.T.A.); (V.L.); (C.D.); (R.H.); (P.W.); (A.D.T.)
| | - Vanessa Lee
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Barrack Road, Weymouth DT4 8UB, UK; (R.P.A.); (R.G.H.); (A.M.L.); (L.N.C.); (T.C.); (M.T.A.); (V.L.); (C.D.); (R.H.); (P.W.); (A.D.T.)
- Department of Chemistry, University of Surrey, Guildford GU2 7XH, UK
| | - Caroline Daumich
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Barrack Road, Weymouth DT4 8UB, UK; (R.P.A.); (R.G.H.); (A.M.L.); (L.N.C.); (T.C.); (M.T.A.); (V.L.); (C.D.); (R.H.); (P.W.); (A.D.T.)
| | - Ruth Hicks
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Barrack Road, Weymouth DT4 8UB, UK; (R.P.A.); (R.G.H.); (A.M.L.); (L.N.C.); (T.C.); (M.T.A.); (V.L.); (C.D.); (R.H.); (P.W.); (A.D.T.)
| | - Peter White
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Barrack Road, Weymouth DT4 8UB, UK; (R.P.A.); (R.G.H.); (A.M.L.); (L.N.C.); (T.C.); (M.T.A.); (V.L.); (C.D.); (R.H.); (P.W.); (A.D.T.)
| | - Krista M. Thomas
- Biotoxin Metrology, National Research Council Canada, Halifax, NS B3Z 3H1, Canada;
| | - Jim R. Ellis
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Pakefield Road, Lowestoft NR33 0HT, UK;
| | - Andrew D. Turner
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Barrack Road, Weymouth DT4 8UB, UK; (R.P.A.); (R.G.H.); (A.M.L.); (L.N.C.); (T.C.); (M.T.A.); (V.L.); (C.D.); (R.H.); (P.W.); (A.D.T.)
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24
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Sprecher BN, Zhang H, Park G, Lin S. Isolation from a fish kill and transcriptomic characterization of Gyrodinium jinhaense off Long Island Sound. HARMFUL ALGAE 2021; 110:102136. [PMID: 34887013 DOI: 10.1016/j.hal.2021.102136] [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: 05/21/2021] [Revised: 11/01/2021] [Accepted: 11/08/2021] [Indexed: 06/13/2023]
Abstract
First found in Korean coastal water, the dinoflagellate Gyrodinium jinhaense is a recently established species with unclear global distribution and unexplored genomic characteristics. From a laboratory fish mortality event off Long Island Sound, USA, we isolated a dinoflagellate, and by microscopic and molecular (18S rRNA gene; >99% identical) analyses found that it resembles G. jinhaense, hence named G. jinhaense strain AP17. Towards developing a genetic database for this dinoflagellate, a transcriptome of this species was sequenced using RNA-seq, producing 6 Gbp of data that was assembled into over 70,000 unigenes. The assembled transcriptome GC content was approximately 56% and the total Benchmarking Universal Single-Copy Orthologs for Eukaryota and Alveolata databases were approximately 50% and 57%, respectfully. Genes involved in grazing, energy generation, genome architecture, and protein synthesis, processing, and degradation were highly represented in the transcriptome. Moreover, fragments of polyketide synthase and saxitoxin genes were found but saxitoxins were not detected in high performance liquid chromatography measurements. With the first reported transcriptome for the Gyrodinium genus, this study will serve as a baseline for future Gyrodinium genomics and toxicological studies.
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Affiliation(s)
- Brittany N Sprecher
- University of Connecticut Avery Point, 1084 Shennecossett Rd, Groton, CT 06340, United States; Current Address - University of Konstanz, Universitätsstraße 10, 78462 Konstanz, Germany.
| | - Huan Zhang
- University of Connecticut Avery Point, 1084 Shennecossett Rd, Groton, CT 06340, United States
| | - Gihong Park
- University of Connecticut Avery Point, 1084 Shennecossett Rd, Groton, CT 06340, United States
| | - Senjie Lin
- University of Connecticut Avery Point, 1084 Shennecossett Rd, Groton, CT 06340, United States.
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25
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Bui QTN, Kim H, Park H, Ki JS. Salinity Affects Saxitoxins (STXs) Toxicity in the Dinoflagellate Alexandrium pacificum, with Low Transcription of SXT-Biosynthesis Genes sxtA4 and sxtG. Toxins (Basel) 2021; 13:toxins13100733. [PMID: 34679026 PMCID: PMC8539879 DOI: 10.3390/toxins13100733] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/13/2021] [Accepted: 10/15/2021] [Indexed: 01/23/2023] Open
Abstract
Salinity is an important factor for regulating metabolic processes in aquatic organisms; however, its effects on toxicity and STX biosynthesis gene responses in dinoflagellates require further elucidation. Herein, we evaluated the physiological responses, toxin production, and expression levels of two STX synthesis core genes, sxtA4 and sxtG, in the dinoflagellate Alexandrium pacificum Alex05 under different salinities (20, 25, 30, 35, and 40 psu). Optimal growth was observed at 30 psu (0.12 cell division/d), but cell growth significantly decreased at 20 psu and was irregular at 25 and 40 psu. The cell size increased at lower salinities, with the highest size of 31.5 µm at 20 psu. STXs eq was highest (35.8 fmol/cell) in the exponential phase at 30 psu. GTX4 and C2 were predominant at that time but were replaced by GTX1 and NeoSTX in the stationary phase. However, sxtA4 and sxtG mRNAs were induced, and their patterns were similar in all tested conditions. PCA showed that gene transcriptional levels were not correlated with toxin contents and salinity. These results suggest that A. pacificum may produce the highest amount of toxins at optimal salinity, but sxtA4 and sxtG may be only minimally affected by salinity, even under high salinity stress.
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Affiliation(s)
- Quynh Thi Nhu Bui
- Department of Biotechnology, Sangmyung University, Seoul 03016, Korea
| | - Hansol Kim
- Department of Biotechnology, Sangmyung University, Seoul 03016, Korea
| | - Hyunjun Park
- Department of Biotechnology, Sangmyung University, Seoul 03016, Korea
| | - Jang-Seu Ki
- Department of Biotechnology, Sangmyung University, Seoul 03016, Korea
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26
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Chan KKY, Kong HK, Tse SPK, Chan Z, Lo PY, Kwok KWH, Lo SCL. Finding Species-Specific Extracellular Surface-Facing Proteomes in Toxic Dinoflagellates. Toxins (Basel) 2021; 13:624. [PMID: 34564629 PMCID: PMC8473415 DOI: 10.3390/toxins13090624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/31/2021] [Accepted: 09/01/2021] [Indexed: 11/27/2022] Open
Abstract
As a sequel to our previous report of the existence of species-specific protein/peptide expression profiles (PEPs) acquired by mass spectrometry in some dinoflagellates, we established, with the help of a plasma-membrane-impermeable labeling agent, a surface amphiesmal protein extraction method (SAPE) to label and capture species-specific surface proteins (SSSPs) as well as saxitoxins-producing-species-specific surface proteins (Stx-SSPs) that face the extracellular space (i.e., SSSPsEf and Stx-SSPsEf). Five selected toxic dinoflagellates, Alexandrium minutum, A. lusitanicum, A. tamarense, Gymnodinium catenatum, and Karenia mikimotoi, were used in this study. Transcriptomic databases of these five species were also constructed. With the aid of liquid chromatography linked-tandem mass spectrometry (LC-MS/MS) and the transcriptomic databases of these species, extracellularly facing membrane proteomes of the five different species were identified. Within these proteomes, 16 extracellular-facing and functionally significant transport proteins were found. Furthermore, 10 SSSPs and 6 Stx-SSPs were identified as amphiesmal proteins but not facing outward to the extracellular environment. We also found SSSPsEf and Stx-SSPsEf in the proteomes. The potential functional correlation of these proteins towards the production of saxitoxins in dinoflagellates and the degree of species specificity were discussed accordingly.
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Affiliation(s)
- Kenrick Kai-yuen Chan
- Department of Applied Biology and Chemical Technology, Faculty of Applied Science and Textiles, The Hong Kong Polytechnic University, Hung Hom, Hong Kong; (K.K.-y.C.); (H.-k.K.); (S.P.-k.T.); (Z.C.); (P.-y.L.); (K.W.H.K.)
| | - Hang-kin Kong
- Department of Applied Biology and Chemical Technology, Faculty of Applied Science and Textiles, The Hong Kong Polytechnic University, Hung Hom, Hong Kong; (K.K.-y.C.); (H.-k.K.); (S.P.-k.T.); (Z.C.); (P.-y.L.); (K.W.H.K.)
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Sirius Pui-kam Tse
- Department of Applied Biology and Chemical Technology, Faculty of Applied Science and Textiles, The Hong Kong Polytechnic University, Hung Hom, Hong Kong; (K.K.-y.C.); (H.-k.K.); (S.P.-k.T.); (Z.C.); (P.-y.L.); (K.W.H.K.)
| | - Zoe Chan
- Department of Applied Biology and Chemical Technology, Faculty of Applied Science and Textiles, The Hong Kong Polytechnic University, Hung Hom, Hong Kong; (K.K.-y.C.); (H.-k.K.); (S.P.-k.T.); (Z.C.); (P.-y.L.); (K.W.H.K.)
| | - Pak-yeung Lo
- Department of Applied Biology and Chemical Technology, Faculty of Applied Science and Textiles, The Hong Kong Polytechnic University, Hung Hom, Hong Kong; (K.K.-y.C.); (H.-k.K.); (S.P.-k.T.); (Z.C.); (P.-y.L.); (K.W.H.K.)
| | - Kevin W. H. Kwok
- Department of Applied Biology and Chemical Technology, Faculty of Applied Science and Textiles, The Hong Kong Polytechnic University, Hung Hom, Hong Kong; (K.K.-y.C.); (H.-k.K.); (S.P.-k.T.); (Z.C.); (P.-y.L.); (K.W.H.K.)
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Samuel Chun-lap Lo
- Department of Applied Biology and Chemical Technology, Faculty of Applied Science and Textiles, The Hong Kong Polytechnic University, Hung Hom, Hong Kong; (K.K.-y.C.); (H.-k.K.); (S.P.-k.T.); (Z.C.); (P.-y.L.); (K.W.H.K.)
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
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27
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Pearson LA, D'Agostino PM, Neilan BA. Recent developments in quantitative PCR for monitoring harmful marine microalgae. HARMFUL ALGAE 2021; 108:102096. [PMID: 34588118 DOI: 10.1016/j.hal.2021.102096] [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: 06/14/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
Marine microalgae produce a variety of specialised metabolites that have toxic effects on humans, farmed fish, and marine wildlife. Alarmingly, many of these compounds bioaccumulate in the tissues of shellfish and higher trophic organisms, including species consumed by humans. Molecular methods are emerging as a potential alternative and complement to the conventional microscopic diagnosis of toxic or otherwise harmful microalgal species. Quantitative PCR (qPCR) in particular, has gained popularity over the past decade as a sensitive, rapid, and cost-effective method for monitoring harmful microalgae. Assays targeting taxonomic marker genes provide the opportunity to identify and quantify (or semi-quantify) microalgal species and importantly to pre-empt bloom events. Moreover, the discovery of paralytic shellfish toxin biosynthesis genes in dinoflagellates has enabled researchers to directly monitor toxigenic species in coastal waters and fisheries. This review summarises the recent developments in qPCR detection methods for harmful microalgae, with emphasis on emerging toxin gene monitoring technologies.
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Affiliation(s)
- Leanne A Pearson
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Paul M D'Agostino
- Chair of Technical Biochemistry, Technical University of Dresden, Dresden, Germany
| | - Brett A Neilan
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia.
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28
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Kim H, Park H, Wang H, Yoo HY, Park J, Ki JS. Low Temperature and Cold Stress Significantly Increase Saxitoxins (STXs) and Expression of STX Biosynthesis Genes sxtA4 and sxtG in the Dinoflagellate Alexandrium catenella. Mar Drugs 2021; 19:291. [PMID: 34064031 PMCID: PMC8224010 DOI: 10.3390/md19060291] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/18/2021] [Accepted: 05/18/2021] [Indexed: 12/22/2022] Open
Abstract
Toxic dinoflagellate Alexandrium spp. produce saxitoxins (STXs), whose biosynthesis pathway is affected by temperature. However, the link between the regulation of the relevant genes and STXs' accumulation and temperature is insufficiently understood. In the present study, we evaluated the effects of temperature on cellular STXs and the expression of two core STX biosynthesis genes (sxtA4 and sxtG) in the toxic dinoflagellate Alexandrium catenella Alex03 isolated from Korean waters. We analyzed the growth rate, toxin profiles, and gene responses in cells exposed to different temperatures, including long-term adaptation (12, 16, and 20 °C) and cold and heat stresses. Temperature significantly affected the growth of A. catenella, with optimal growth (0.49 division/day) at 16 °C and the largest cell size (30.5 µm) at 12 °C. High concentration of STXs eq were detected in cells cultured at 16 °C (86.3 fmol/cell) and exposed to cold stress at 20→12 °C (96.6 fmol/cell) compared to those at 20 °C and exposed to heat stress. Quantitative real-time PCR (qRT-PCR) revealed significant gene expression changes of sxtA4 in cells cultured at 16 °C (1.8-fold) and cold shock at 20→16 °C (9.9-fold). In addition, sxtG was significantly induced in cells exposed to cold shocks (20→16 °C; 19.5-fold) and heat stress (12→20 °C; 25.6-fold). Principal component analysis (PCA) revealed that low temperature (12 and 16 °C) and cold stress were positively related with STXs' production and gene expression levels. These results suggest that temperature may affect the toxicity and regulation of STX biosynthesis genes in dinoflagellates.
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Affiliation(s)
- Hansol Kim
- Department of Biotechnology, Sangmyung University, Seoul 03016, Korea; (H.K.); (H.P.); (H.W.); (H.Y.Y.)
| | - Hyunjun Park
- Department of Biotechnology, Sangmyung University, Seoul 03016, Korea; (H.K.); (H.P.); (H.W.); (H.Y.Y.)
| | - Hui Wang
- Department of Biotechnology, Sangmyung University, Seoul 03016, Korea; (H.K.); (H.P.); (H.W.); (H.Y.Y.)
| | - Hah Young Yoo
- Department of Biotechnology, Sangmyung University, Seoul 03016, Korea; (H.K.); (H.P.); (H.W.); (H.Y.Y.)
| | - Jaeyeon Park
- Environment and Resource Convergence Center, Advanced Institute of Convergence Technologies, Suwon 16229, Korea
| | - Jang-Seu Ki
- Department of Biotechnology, Sangmyung University, Seoul 03016, Korea; (H.K.); (H.P.); (H.W.); (H.Y.Y.)
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Yu RC, Zhang QC, Liu Y, Chen ZF, Geng HX, Dai L, Lin ZR, Tang WJ, Kong FZ, Yan T, Zhou MJ. The dinoflagellate Alexandrium catenella producing only carbamate toxins may account for the seafood poisonings in Qinhuangdao, China. HARMFUL ALGAE 2021; 103:101980. [PMID: 33980430 DOI: 10.1016/j.hal.2021.101980] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/25/2020] [Accepted: 01/21/2021] [Indexed: 06/12/2023]
Abstract
An outbreak of paralytic shellfish poisoning, recorded in April 2016 in Qinhuangdao China, was suspected to be caused by a toxic species in genus Alexandrium. Shortly after the poisoning outbreak, shellfish and net-concentrated phytoplankton samples were collected from the Bohai Sea, and analysed using high performance liquid chromatography coupled with fluorescence detection. Paralytic shellfish toxins (PSTs) were detected in both phytoplankton and shellfish samples, with similar toxin profiles dominated by carbamate toxins. High throughput sequencing data for phytoplankton samples collected previously in the coastal waters of Qinhuangdao were then analysed, and 8 operational taxonomic units (OTUs) were assigned to Alexandrium affine, A. andersonii/A. ostenfeldii, A. catenella, A. fraterculus, A. hiranoi/A. pseudogonyaulax, A. margalefii, A. pacificum and A. pohangense, among which A. catenella, A. pacificum and A. ostenfeldii could be potential producers of PSTs. During a cruise in 2019, three isolates of Alexandrium were established by cyst germination, and identified as A. catenella based on the sequences of the 28S ribosomal RNA gene (28S rDNA) D1-D2 region. Interestingly, all the three strains had the same toxin profile consisting of gonyautoxins 1, 3, 4 (GTX1, 3, 4) and neosaxitoxin (NEO). The toxin profile is similar to those of phytoplankton samples collected previously in the coastal waters of Qinhuangdao, but remarkably different from the general toxin profile of A. catenella dominated by N-sulfocarbamoyl toxins C1-2 in the Bohai Sea and the Yellow Sea. The results suggest that A. catenella is most likely to be the causative species of the poisoning outbreak in Qinhuangdao. As far as we know, this is the first report of A. catenella in the Bohai Sea producing PSTs dominated by high potent gonyautoxins GTX1-4. Occurrence of the highly toxic A. catenella will increase the risk of paralytic shellfish poisoning, which necessitates in-depth mechanism studies and increasing monitoring efforts.
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Affiliation(s)
- Ren-Cheng Yu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Key Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
| | - Qing-Chun Zhang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Key Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China
| | - Yang Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Zhen-Fan Chen
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China
| | - Hui-Xia Geng
- Changjiang River Estuary Ecosystem Research Station, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Li Dai
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhuo-Ru Lin
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wen-Jiao Tang
- College of Marine Life Science, Ocean University of China, Qingdao 266003, China
| | - Fan-Zhou Kong
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Key Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China
| | - Tian Yan
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Key Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China
| | - Ming-Jiang Zhou
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
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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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Geffroy S, Lechat MM, Le Gac M, Rovillon GA, Marie D, Bigeard E, Malo F, Amzil Z, Guillou L, Caruana AMN. From the sxtA4 Gene to Saxitoxin Production: What Controls the Variability Among Alexandrium minutum and Alexandrium pacificum Strains? Front Microbiol 2021; 12:613199. [PMID: 33717003 PMCID: PMC7944994 DOI: 10.3389/fmicb.2021.613199] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 02/03/2021] [Indexed: 12/22/2022] Open
Abstract
Paralytic shellfish poisoning (PSP) is a human foodborne syndrome caused by the consumption of shellfish that accumulate paralytic shellfish toxins (PSTs, saxitoxin group). In PST-producing dinoflagellates such as Alexandrium spp., toxin synthesis is encoded in the nuclear genome via a gene cluster (sxt). Toxin production is supposedly associated with the presence of a 4th domain in the sxtA gene (sxtA4), one of the core genes of the PST gene cluster. It is postulated that gene expression in dinoflagellates is partially constitutive, with both transcriptional and post-transcriptional processes potentially co-occurring. Therefore, gene structure and expression mode are two important features to explore in order to fully understand toxin production processes in dinoflagellates. In this study, we determined the intracellular toxin contents of twenty European Alexandrium minutum and Alexandrium pacificum strains that we compared with their genome size and sxtA4 gene copy numbers. We observed a significant correlation between the sxtA4 gene copy number and toxin content, as well as a moderate positive correlation between the sxtA4 gene copy number and genome size. The 18 toxic strains had several sxtA4 gene copies (9-187), whereas only one copy was found in the two observed non-toxin producing strains. Exploration of allelic frequencies and expression of sxtA4 mRNA in 11 A. minutum strains showed both a differential expression and specific allelic forms in the non-toxic strains compared with the toxic ones. Also, the toxic strains exhibited a polymorphic sxtA4 mRNA sequence between strains and between gene copies within strains. Finally, our study supported the hypothesis of a genetic determinism of toxin synthesis (i.e., the existence of several genetic isoforms of the sxtA4 gene and their copy numbers), and was also consistent with the hypothesis that constitutive gene expression and moderation by transcriptional and post-transcriptional regulation mechanisms are the cause of the observed variability in the production of toxins by A. minutum.
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Affiliation(s)
| | | | | | | | - Dominique Marie
- Sorbonne Université, CNRS, UMR 7144 Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
| | - Estelle Bigeard
- Sorbonne Université, CNRS, UMR 7144 Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
| | | | | | - Laure Guillou
- Sorbonne Université, CNRS, UMR 7144 Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
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Cho Y, Hidema S, Omura T, Koike K, Koike K, Oikawa H, Konoki K, Oshima Y, Yotsu-Yamashita M. SxtA localizes to chloroplasts and changes to its 3'UTR may reduce toxin biosynthesis in non-toxic Alexandrium catenella (Group I) ✰. HARMFUL ALGAE 2021; 101:101972. [PMID: 33526188 DOI: 10.1016/j.hal.2020.101972] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/14/2020] [Accepted: 12/19/2020] [Indexed: 06/12/2023]
Abstract
SxtA is the enzyme that catalyses the first step of saxitoxin biosynthesis. We developed an immunofluorescent method to detect SxtA using antibodies against SxtA peptides. Confocal microscopy revealed the presence of abundant, sub-cellularly localized signal in cells of toxic species and its absence in non-toxic species. Co-localization of SxtA with Rubisco II and ultra-structural observation by transmission electron microscopy strongly suggested the association of SxtA with chloroplasts. We also characterized a non-toxic sub-clone of Alexandrium catenella (Group I) to elucidate the mutation responsible for its loss of toxicity. Although sxtA4 gene copy number was indistinguishable in toxic and non-toxic sub-clones, mRNA and protein expression were significantly reduced in the non-toxic sub-clone and we uncovered sequence variation at the 3' untranslated region (3'UTR) of sxtA4 mRNA. We propose that differences in the sxtA4 mRNA 3'UTR lead to down-regulation of STX biosynthesis post-transcriptionally, thereby explaining the differences in toxicity amongst different A. catenella (Group I) sub-clones.
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Affiliation(s)
- Yuko Cho
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan.
| | - Shizu Hidema
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University, 1 Hikariga-oka, Fukushima 960-1295, Japan
| | - Takuo Omura
- Laboratory of Aquatic Science Consultant Co., Ltd. 2-30-17, Higashikamata, Ota-ku, Tokyo 144-0031, Japan
| | - Kazuhiko Koike
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
| | - Kanae Koike
- Natural Science Center for Basic Research and Development, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
| | - Hiroshi Oikawa
- Japan Fisheries Research and Education Agency, Fisheries Technology Institute, 2-12-4 Fukuura, Kanazawa, Yokohama, Kanagawa 236-8648, Japan
| | - Keiichi Konoki
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Yasukatsu Oshima
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
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Carroll AR, Copp BR, Davis RA, Keyzers RA, Prinsep MR. Marine natural products. Nat Prod Rep 2021; 38:362-413. [PMID: 33570537 DOI: 10.1039/d0np00089b] [Citation(s) in RCA: 198] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This review covers the literature published in 2019 for marine natural products (MNPs), with 719 citations (701 for the period January to December 2019) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1490 in 440 papers for 2019), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. Methods used to study marine fungi and their chemical diversity have also been discussed.
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Affiliation(s)
- Anthony R Carroll
- School of Environment and Science, Griffith University, Gold Coast, Australia. and Griffith Institute for Drug Discovery, Griffith University, Brisbane, Australia
| | - Brent R Copp
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Rohan A Davis
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, Australia and School of Enivironment and Science, Griffith University, Brisbane, Australia
| | - Robert A Keyzers
- Centre for Biodiscovery, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Michèle R Prinsep
- Chemistry, School of Science, University of Waikato, Hamilton, New Zealand
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34
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Biosynthesis of marine toxins. Curr Opin Chem Biol 2020; 59:119-129. [DOI: 10.1016/j.cbpa.2020.06.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/21/2020] [Accepted: 06/23/2020] [Indexed: 12/18/2022]
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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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De novo Transcriptome of the Non-saxitoxin Producing Alexandrium tamutum Reveals New Insights on Harmful Dinoflagellates. Mar Drugs 2020; 18:md18080386. [PMID: 32722301 PMCID: PMC7460133 DOI: 10.3390/md18080386] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [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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Verma A, Hughes DJ, Harwood DT, Suggett DJ, Ralph PJ, Murray SA. Functional significance of phylogeographic structure in a toxic benthic marine microbial eukaryote over a latitudinal gradient along the East Australian Current. Ecol Evol 2020; 10:6257-6273. [PMID: 32724512 PMCID: PMC7381561 DOI: 10.1002/ece3.6358] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 03/24/2020] [Accepted: 04/22/2020] [Indexed: 01/04/2023] Open
Abstract
Genetic diversity in marine microbial eukaryotic populations (protists) drives their ecological success by enabling diverse phenotypes to respond rapidly to changing environmental conditions. Despite enormous population sizes and lack of barriers to gene flow, genetic differentiation that is associated with geographic distance, currents, and environmental gradients has been reported from planktonic protists. However, for benthic protists, which have reduced dispersal opportunities, phylogeography and its phenotypic significance are little known. In recent years, the East Australian Current (EAC) has intensified its southward flow, associated with the tropicalization of temperate waters. Benthic harmful algal species have been increasingly found in south-eastern Australia. Yet little is known about the potential of these species to adapt or extend their range in relation to changing conditions. Here, we examine genetic diversity and functional niche divergence in a toxic benthic dinoflagellate, Ostreopsis cf. siamensis, along a 1,500 km north-south gradient in southeastern Australia. Sixty-eight strains were established from eight sampling sites. The study revealed long-standing genetic diversity among strains established from the northern-most sites, along with large phenotypic variation in observed physiological traits such as growth rates, cell volume, production of palytoxin-like compounds, and photophysiological parameters. Strains from the southern populations were more uniform in both genetic and functional traits, and have possibly colonized their habitats more recently. Our study reports significant genetic and functional trait variability in a benthic harmful algal species, indicative of high adaptability, and a possible climate-driven range extension. The observed high trait variation may facilitate development of harmful algal blooms under dynamic coastal environmental conditions.
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Affiliation(s)
- Arjun Verma
- Climate Change ClusterUniversity of Technology SydneyUltimoNSWAustralia
| | - David J. Hughes
- Climate Change ClusterUniversity of Technology SydneyUltimoNSWAustralia
| | | | - David J. Suggett
- Climate Change ClusterUniversity of Technology SydneyUltimoNSWAustralia
| | - Peter J. Ralph
- Climate Change ClusterUniversity of Technology SydneyUltimoNSWAustralia
| | - Shauna A. Murray
- Climate Change ClusterUniversity of Technology SydneyUltimoNSWAustralia
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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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Akbar MA, Mohd Yusof NY, Tahir NI, Ahmad A, Usup G, Sahrani FK, Bunawan H. Biosynthesis of Saxitoxin in Marine Dinoflagellates: An Omics Perspective. Mar Drugs 2020; 18:md18020103. [PMID: 32033403 PMCID: PMC7073992 DOI: 10.3390/md18020103] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/09/2020] [Accepted: 01/09/2020] [Indexed: 02/07/2023] Open
Abstract
Saxitoxin is an alkaloid neurotoxin originally isolated from the clam Saxidomus giganteus in 1957. This group of neurotoxins is produced by several species of freshwater cyanobacteria and marine dinoflagellates. The saxitoxin biosynthesis pathway was described for the first time in the 1980s and, since then, it was studied in more than seven cyanobacterial genera, comprising 26 genes that form a cluster ranging from 25.7 kb to 35 kb in sequence length. Due to the complexity of the genomic landscape, saxitoxin biosynthesis in dinoflagellates remains unknown. In order to reveal and understand the dynamics of the activity in such impressive unicellular organisms with a complex genome, a strategy that can carefully engage them in a systems view is necessary. Advances in omics technology (the collective tools of biological sciences) facilitated high-throughput studies of the genome, transcriptome, proteome, and metabolome of dinoflagellates. The omics approach was utilized to address saxitoxin-producing dinoflagellates in response to environmental stresses to improve understanding of dinoflagellates gene–environment interactions. Therefore, in this review, the progress in understanding dinoflagellate saxitoxin biosynthesis using an omics approach is emphasized. Further potential applications of metabolomics and genomics to unravel novel insights into saxitoxin biosynthesis in dinoflagellates are also reviewed.
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Affiliation(s)
- Muhamad Afiq Akbar
- School of Bioscience and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia;
| | - Nurul Yuziana Mohd Yusof
- Department of Earth Science and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia; (N.Y.M.Y.); (F.K.S.)
| | - Noor Idayu Tahir
- Malaysian Palm Oil Board, No 6, Persiaran Institusi, Bandar Baru Bangi, Kajang 43000, Selangor, Malaysia;
| | - Asmat Ahmad
- University College Sabah Foundation, Jalan Sanzac, Kota Kinabalu 88100, Sabah, Malaysia; (A.A.); (G.U.)
| | - Gires Usup
- University College Sabah Foundation, Jalan Sanzac, Kota Kinabalu 88100, Sabah, Malaysia; (A.A.); (G.U.)
| | - Fathul Karim Sahrani
- Department of Earth Science and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia; (N.Y.M.Y.); (F.K.S.)
| | - Hamidun Bunawan
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia
- Correspondence: ; Tel.: +60-389-214-546
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Konstantinou D, Mavrogonatou E, Zervou SK, Giannogonas P, Gkelis S. Bioprospecting Sponge-Associated Marine Cyanobacteria to Produce Bioactive Compounds. Toxins (Basel) 2020; 12:toxins12020073. [PMID: 31979262 PMCID: PMC7076795 DOI: 10.3390/toxins12020073] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 12/23/2022] Open
Abstract
Marine cyanobacteria are considered a prolific source of bioactive natural products with a range of biotechnological and pharmacological applications. However, data on the production of natural compounds from sponge-associated cyanobacteria are scarce. This study aimed to assess the potential of sponge-associated cyanobacteria strains representing different taxonomic groups for the production of bioactive compounds and the biological activity of their extracts. Phylogenetic analysis of sponge-associated cyanobacteria and screening for the presence of genes encoding non-ribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs) were performed. Methanol extracts of the sponge-associated strains were analyzed for cyanotoxin production and tested for antioxidant activity and cytotoxic activity against several human cancer cell lines and pathogenic bacteria. PKS were detected in all sponge-associated strains examined, indicating the metabolic potential of the isolates. PKS genes were more ubiquitous than NRPS genes. Cyanotoxins (i.e., cylindrospermopsin, anatoxin-a, nodularin, and microcystins) were not detected in any of the sponge-associated cyanobacterial strains. Strains belonging to Leptothoe, Pseudanabaena, and Synechococcus were found to have activity mainly against Staphylococcus aureus. In addition, sponge-associated Leptothoe strains (TAU-MAC 0915, 1015, 1115, and 1215) were found to be highly cytotoxic and in most cases more effective against human cancer cell lines than against normal cells. Extracts with the most promising bioactivity deserve further investigation in order to isolate and identify the bioactive molecule(s).
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Affiliation(s)
- Despoina Konstantinou
- Department of Botany, School of Biology, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece; (D.K.); (E.M.); (S.-K.Z.); (P.G.)
| | - Eleni Mavrogonatou
- Department of Botany, School of Biology, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece; (D.K.); (E.M.); (S.-K.Z.); (P.G.)
- Laboratory of Cell Proliferation and Ageing, Institute of Biosciences & Applications, National Centre for Scientific Research “Demokritos”, Patriarchou Grigoriou & Neapoleos, Agia Paraskevi, 15341 Athens, Greece
| | - Sevasti-Kiriaki Zervou
- Department of Botany, School of Biology, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece; (D.K.); (E.M.); (S.-K.Z.); (P.G.)
- Laboratory of Photo-Catalytic Processes and Environmental Chemistry, Institute of Nanoscience & Nanotechnology, National Centre for Scientific Research “Demokritos”, Patriarchou Grigoriou & Neapoleos, Agia Paraskevi, 15341 Athens, Greece
| | - Panagiotis Giannogonas
- Department of Botany, School of Biology, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece; (D.K.); (E.M.); (S.-K.Z.); (P.G.)
- Laboratory of Cell Proliferation and Ageing, Institute of Biosciences & Applications, National Centre for Scientific Research “Demokritos”, Patriarchou Grigoriou & Neapoleos, Agia Paraskevi, 15341 Athens, Greece
| | - Spyros Gkelis
- Department of Botany, School of Biology, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece; (D.K.); (E.M.); (S.-K.Z.); (P.G.)
- Correspondence: ; Tel.: +30-231-099-8083
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Ciguatera Fish Poisoning: The Risk from an Aotearoa/New Zealand Perspective. Toxins (Basel) 2020; 12:toxins12010050. [PMID: 31952334 PMCID: PMC7020403 DOI: 10.3390/toxins12010050] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/07/2020] [Accepted: 01/10/2020] [Indexed: 01/24/2023] Open
Abstract
Gambierdiscus and Fukuyoa species have been identified in Aotearoa/New Zealand's coastal waters and G. polynesiensis, a known producer of ciguatoxins, has been isolated from Rangitāhua/Kermadec Islands (a New Zealand territory). The warming of the Tasman Sea and the waters around New Zealand's northern subtropical coastline heighten the risk of Gambierdiscus proliferating in New Zealand. If this occurs, the risk of ciguatera fish poisoning due to consumption of locally caught fish will increase. Research, including the development and testing of sampling methods, molecular assays, and chemical and toxicity tests, will continue. Reliable monitoring strategies are important to manage and mitigate the risk posed by this emerging threat. The research approaches that have been made, many of which will continue, are summarised in this review.
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Murray SA, Ruvindy R, Kohli GS, Anderson DM, Brosnahan ML. Evaluation of sxtA and rDNA qPCR assays through monitoring of an inshore bloom of Alexandrium catenella Group 1. Sci Rep 2019; 9:14532. [PMID: 31601884 PMCID: PMC6787220 DOI: 10.1038/s41598-019-51074-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 09/24/2019] [Indexed: 12/16/2022] Open
Abstract
Alexandrium catenella (formerly A. tamarense Group 1, or A. fundyense) is the leading cause of Paralytic Shellfish Poisoning in North and South America, Europe, Africa, Australia and Asia. The quantification of A.catenella via sxtA, a gene involved in Paralytic Shellfish Toxin synthesis, may be a promising approach, but has not been evaluated in situ on blooms of A. catenella, in which cell abundances may vary from not detectable to in the order of 106 cells L-1. In this study, we compared sxtA assay performance to a qPCR assay targeted to a species-specific region of ribosomal DNA (rDNA) and an established fluorescent in situ hybridization (FISH) microscopy method. Passing-Bablok regression analyses revealed the sxtA assay to overestimate abundances when <5 cell equivalents A. catenella DNA were analysed, but otherwise was closer to microscopy estimates than the rDNA assay, which overestimated abundance across the full range of concentrations analysed, indicative of a copy number difference between the bloom population and a culture used for assay calibration a priori. In contrast, the sxtA assay performed more consistently, indicating less copy number variation. The sxtA assay was generally reliable, fast and effective in quantifying A. catenella and was predictive of PST contamination of shellfish.
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Affiliation(s)
- Shauna A Murray
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia.
| | - Rendy Ruvindy
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia
| | - Gurjeet S Kohli
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia
- Ramaciotti Centre for Gene Function Analysis, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Donald M Anderson
- Woods Hole Oceanographic Institution, MS # 32, 266 Woods Hole Road, Woods Hole, Massachusetts, 02543, United States
| | - Michael L Brosnahan
- Woods Hole Oceanographic Institution, MS # 32, 266 Woods Hole Road, Woods Hole, Massachusetts, 02543, United States
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Identification of a Novel Saxitoxin Analogue, 12β-Deoxygonyautoxin 3, in the Cyanobacterium, Anabaena circinalis (TA04). Toxins (Basel) 2019; 11:toxins11090539. [PMID: 31527551 PMCID: PMC6784053 DOI: 10.3390/toxins11090539] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 12/11/2022] Open
Abstract
Saxitoxin (STX) and its analogues, the potent voltage-gated sodium channel blockers, are biosynthesized by freshwater cyanobacteria and marine dinoflagellates. We previously identified several biosynthetic intermediates in the extract of the cyanobacterium, Anabaena circinalis (TA04), that are primarily produced during the early and middle stages in the biosynthetic pathway to produce STX. These findings allowed us to propose a putative biosynthetic pathway responsible for STX production based on the structures of these intermediates. In the present study, we identified 12β-deoxygonyautoxin 3 (12β-deoxyGTX3), a novel STX analogue produced by A. circinalis (TA04), by comparing the retention time and MS/MS fragmentation pattern with those of synthetic standards using LC-MS. The presence of this compound in A. circinalis (TA04) is consistent with stereoselective enzymatic oxidations at C11 and C12, and 11-O-sulfation, during the late stage of STX biosynthesis, as proposed in previous studies.
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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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