Harmful Algae最新文献

{"title":"Prevalence and distribution of dissolved paralytic shellfish toxins in seawater in the Yellow Sea and the Bohai Sea, China","authors":"Xiaoyun Wang ,&nbsp;Jiangbing Qiu ,&nbsp;Dongyue Li ,&nbsp;Aifeng Li","doi":"10.1016/j.hal.2024.102730","DOIUrl":"10.1016/j.hal.2024.102730","url":null,"abstract":"<div><div>Paralytic shellfish toxins (PSTs) could be secreted by PSTs-producing microalgae or released by ruptured cells in seawater. In this study, the distribution of dissolved PSTs in the Yellow Sea and the Bohai Sea, China, was investigated by two cruises in April and July 2023. Seawater samples were collected from the surface, middle and bottom layers, and the profiles of PSTs were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the spatial distribution characteristics of dissolved PSTs and their correlation with environmental factors were explored. Results showed that C1/2, GTX1/4, GTX2/3 and dcGTX2/3, were detected in seawater samples in both spring and summer, with the detection rates 100 % and 97.6 %, respectively. The total PST (ΣPSTs) concentrations ranged in 12 ∼ 590 pmol L⁻¹, 9.3 ∼ 546 pmol L⁻¹, 12 ∼ 2,452 pmol L⁻¹, and not detected (nd) ∼ 188 pmol L⁻¹ in seawater samples collected from the surface, middle and bottom layers in spring, and the surface layer in summer, respectively. Concentrations of PSTs markedly varied in the vertical water column in different sea regions. Generally, concentrations of ΣPSTs in the bottom seawater were higher than those in the surface and middle layers in the Bohai Sea and the North Yellow Sea, but no significant difference in the different water layers in the South Yellow Sea. In addition, concentrations of ΣPSTs in surface waters were much lower in summer than those in spring. In both spring and summer, dissolved PSTs in surface seawater were mainly distributed in the South Yellow Sea. These results indicate that PSTs were prevalent in the Yellow Sea and the Bohai Sea, of which the potential hazard to marine organisms should be highly concerned.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"139 ","pages":"Article 102730"},"PeriodicalIF":5.5,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Potential siderophore-dependent mutualism in the harmful dinoflagellate Alexandrium pacificum (Group IV) and bacterium Photobacterium sp. TY1-4 under iron-limited conditions","authors":"Yue Jiang ,&nbsp;Hyeon Ho Shin ,&nbsp;Bum Soo Park ,&nbsp;Zhun Li","doi":"10.1016/j.hal.2024.102726","DOIUrl":"10.1016/j.hal.2024.102726","url":null,"abstract":"<div><div>Specific bacterial species induce algal blooms by producing growth-promoting substances, such as siderophores, under iron-limited conditions. However, the molecular mechanisms underlying these effects remain poorly understood. This study investigates the interactions between the harmful dinoflagellate <em>Alexandrium pacificum</em> (Group IV) and siderophore-producing bacteria, with a focus on iron acquisition facilitated by bacterial siderophores. During algal bloom seasons in the South Sea of Korea, <em>Photobacterium</em> sp. TY1-4 was isolated, which enhances <em>A. pacificum</em> cell density under iron-deficient conditions, TY1-4 can use the sterile exudates from <em>A. pacificum</em> as the sole source of carbon<em>,</em> suggesting a mutualistic relationship. Transcriptomic and genomic analyses revealed siderophore-mediated redox-based signaling and non-reductive pathways enhancing iron bioavailability. <em>Photobacterium</em> sp. TY1-4 initiates siderophore production through quorum sensing, whereas <em>A. pacificum</em> utilizes specific receptors and transporters for hydroxamate-type siderophores (<em>ApFHUA</em> and <em>ApFHUC</em>) to uptake iron. Three redox key iron-uptake genes were also identified in <em>A. pacificum</em>: membrane-bound ferroxidase <em>ApFET3</em>, high-affinity iron permease <em>ApFTR1</em>, and ferric-chelate reductases/oxidoreductases <em>ApFRE1</em>, with transcription levels inversely related to bioavailable iron. Increased iron bioavailability mediated by siderophores alleviates iron stress in <em>A. pacificum</em>, supporting its growth in iron-scarce environments. Additionally, <em>A. pacificum</em> co-cultured with <em>Photobacterium</em> sp. TY1-4 synthesized high-toxicity STXs, including GTX4, GTX2, and STX. These findings highlight the critical role of bacterial siderophores in iron binding and their potential impact on harmful algal bloom dynamics.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"139 ","pages":"Article 102726"},"PeriodicalIF":5.5,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1568988324001598/pdfft?md5=193af3676fa67a46f3e3f7035ea047ab&pid=1-s2.0-S1568988324001598-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response to the CO2 concentrating mechanisms and transcriptional time series analysis of Ulva prolifera under inorganic carbon limitation","authors":"Jingyi Sun ,&nbsp;Wei Dai ,&nbsp;Shuang Zhao ,&nbsp;Jinlin Liu ,&nbsp;Jianheng Zhang ,&nbsp;Juntian Xu ,&nbsp;Peimin He","doi":"10.1016/j.hal.2024.102727","DOIUrl":"10.1016/j.hal.2024.102727","url":null,"abstract":"<div><div><em>Ulva prolifera</em> is a dominant species in green tides and has been affecting marine ecosystem for many years. Due to the low availability of CO₂ in the environment, <em>U. prolifera</em> utilizes the CO₂ concentrating mechanisms (CCMs) to increase intracellular inorganic carbon concentration. However, the transcriptional response mechanism and temporal changes of <em>U. prolifera</em> CCMs based on transcriptomics have not been thoroughly described. Therefore, we induced <em>U. prolifera</em> CCMs in a low CO₂ environment to explore the dynamic regulation of CCMs expression under inadequate inorganic carbon supply. The results showed that inorganic carbon limitation increased the inorganic carbon affinity of <em>U. prolifera</em>, upregulating CCMs. The first 24 h of inorganic carbon environmental changes were the most active period for <em>U. prolifera</em>'s expression regulation. <em>U. prolifera</em> gradually achieved a new steady state by regulating metabolic processes such as nucleic acids, energy, and ethylene-activated signaling pathways. In the carbon fixation system of <em>U. prolifera</em>, there are characteristics of both biophysical and biochemical CCMs. After 24 h of inorganic carbon limitation, the biophysical CCMs becomes more effective under conditions of inorganic carbon depletion. This study aids in exploring the CCMs of <em>U. prolifera</em> and their evolution in response to environmental changes<em>.</em></div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"139 ","pages":"Article 102727"},"PeriodicalIF":5.5,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Production of extracellular superoxide contributes to photosynthesis via elimination of reducing power and regeneration of NADP+ in the red-tide-forming raphidophyte Chattonella marina complex","authors":"Koki Yuasa ,&nbsp;Takayoshi Ichikawa ,&nbsp;Yuma Ishikawa ,&nbsp;Haruhiko Jimbo ,&nbsp;Maki Kawai-Yamada ,&nbsp;Tomoyuki Shikata ,&nbsp;Yoshitaka Nishiyama","doi":"10.1016/j.hal.2024.102712","DOIUrl":"10.1016/j.hal.2024.102712","url":null,"abstract":"<div><p>The raphidophyte <em>Chattonella marina</em> complex (hereafter <em>Chattonella</em>) consists of noxious red-tide-forming algae that are damaging to fish farms. <em>Chattonella</em> produces and secretes large amounts of the superoxide anion (•O₂⁻), and the production of extracellular •O₂⁻ has been associated with fish mortality. We reported previously that photosynthetic electron transport is correlated with the production of •O₂⁻ in the genus <em>Chattonella</em>. However, the physiological roles of the production of extracellular •O₂⁻ remain to be clarified. In the present study, we examined the effects of the production of extracellular •O₂⁻ on photosynthesis and cell proliferation in two strains of <em>Chattonella</em>, namely, Ago03, a highly toxic strain that produces large amounts of •O₂⁻ externally, and Ago04, a low-toxicity strain that produces very small amounts of •O₂⁻. Both the growth rate and the net photosynthetic activity of Ago04 were higher than those of Ago03. In Ago04, levels of Rubisco and 3-phosphoglycerate, the product of the reaction catalyzed by Rubisco, were 4-fold higher than those in Ago03, suggesting the higher photosynthetic activity of Ago04. In the presence of glycolaldehyde, a specific inhibitor of the Calvin-Benson cycle, the levels of NADP⁺ and the photosynthetic parameter qP declined under strong light in Ago04. By contrast, levels of NADP⁺ and qP in Ago03 changed less significantly than those in Ago04. Given that •O₂⁻ is produced by a putative NADPH oxidase that converts O₂ to •O₂⁻ in <em>Chattonella</em>, it seems likely that the production of •O₂⁻ might play a role not only in the elimination of excess reducing power of NADPH from the cell, via •O₂⁻, but also in the regeneration of NADP⁺, as a result of the action of NADPH oxidase, which oxidizes NADPH, to maintain photosynthetic electron transport.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"139 ","pages":"Article 102712"},"PeriodicalIF":5.5,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1568988324001458/pdfft?md5=0faa71a246e0adac6716c6df333523f0&pid=1-s2.0-S1568988324001458-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diversity, toxicity, and distribution of potentially toxic diatoms in Antarctic waters––With description of Pseudo-nitzschia meridionalis sp. nov. and P. glacialis sp. nov.","authors":"Nina Lundholm ,&nbsp;Anneliese L. Christensen ,&nbsp;Anna K.J. Olesen ,&nbsp;Bánk Beszteri ,&nbsp;Sarah Lena Eggers ,&nbsp;Bernd Krock ,&nbsp;Andreas Altenburger","doi":"10.1016/j.hal.2024.102724","DOIUrl":"10.1016/j.hal.2024.102724","url":null,"abstract":"<div><div>Diatoms of the genus <em>Pseudo-nitzschia</em>, known for their potential toxicity, are integral to the phytoplankton community of the Southern Ocean, which surrounds Antarctica. Despite their ecological importance, the diversity and toxicity of <em>Pseudo-nitzschia</em> in this region remain underexplored. Globally, these diatoms are notorious for forming harmful algal blooms in temperate and tropical waters, causing significant impacts on marine life, ecosystems, and coastal economies. However, detailed information on the diversity, morphology, and toxicity of <em>Pseudo-nitzschia</em> species in Antarctic waters is limited, with molecular characterizations of these species being particularly scarce.</div><div>During three research expeditions to the Southern Ocean, monoclonal strains of <em>Pseudo-nitzschia</em> were isolated and cultivated. Stored samples from a fourth expedition, the Brategg expedition, were used to complete the description of particularly <em>P. turgidula</em>. Through electron microscopy and molecular analysis, two novel species were identified—<em>Pseudo-nitzschia meridionalis</em> sp. nov. and <em>Pseudo-nitzschia glacialis</em> sp. nov.—alongside the previously described species <em>P. subcurvata, P. turgiduloides</em>, and <em>P. turgidula</em>. Toxin assays revealed no detectable levels of domoic acid in <em>P. turgiduloides, P. turgidula, P. meridionalis</em> sp. nov. and <em>P. glacialis</em> sp. nov. Conversely, <em>P. subcurvata</em> was reported in a related study to produce domoic acid and its isomer, isodomoic acid C.</div><div>These findings emphasize the need for comprehensive research on the phytoplankton of Antarctic waters, which is currently a largely uncharted domain. With the looming threat of climate change, understanding the dynamics of potentially harmful algal populations in this region is becoming increasingly critical.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"139 ","pages":"Article 102724"},"PeriodicalIF":5.5,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1568988324001574/pdfft?md5=7e59ef19d51e6398fbe85782b7c1ad4b&pid=1-s2.0-S1568988324001574-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced eDNA monitoring for detection of viable harmful algal bloom species using propidium monoazide","authors":"Kun-woo Yun,&nbsp;Hwa-seong Son,&nbsp;Min-jun Seong,&nbsp;Seung-min Lee,&nbsp;Mu-chan Kim","doi":"10.1016/j.hal.2024.102725","DOIUrl":"10.1016/j.hal.2024.102725","url":null,"abstract":"<div><p>This study investigated the use of propidium monoazide (PMA) to improve the accuracy of environmental DNA (eDNA) monitoring by selectively detecting intracellular DNA (iDNA) from living cells, while excluding extracellular DNA (exDNA) from dead organisms. eDNA samples were collected from various depths off the coast of Tongyeong, South Korea, and analyzed alongside environmental factors, such as temperature, dissolved oxygen, turbidity, and nutrient levels. The results showed that PMA-treated iDNA provided a more accurate estimate of viable harmful algal bloom species (HABs) than total eDNA and DNase-treated iDNA. Strong correlations were found between iDNA (PMA) and environmental factors, particularly nutrient levels and turbidity, suggesting its effectiveness in biological environments. The iDNA (PMA) concentrations were higher in the surface and bottom layers, indicating that these layers were more indicative of living organisms in marine environments. The application of PMA in eDNA monitoring reduces false positives and enhances the detection accuracy of viable HAB species, representing a promising tool for real-time monitoring and management of marine ecosystems.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"139 ","pages":"Article 102725"},"PeriodicalIF":5.5,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142232184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intracellular abundance, localization, and enzymatic activity of a saxitoxin biosynthesis enzyme, SxtG, in two sister subclones of the dinoflagellate Alexandrium catenella with extremely different levels of paralytic shellfish toxins","authors":"Yuko Cho ,&nbsp;Shizu Hidema ,&nbsp;Takuo Omura ,&nbsp;Shigeki Tsuchiya ,&nbsp;Keiichi Konoki ,&nbsp;Yasukatsu Oshima ,&nbsp;Mari Yotsu-Yamashita","doi":"10.1016/j.hal.2024.102723","DOIUrl":"10.1016/j.hal.2024.102723","url":null,"abstract":"<div><p>Paralytic shellfish poisoning is caused by saxitoxin (STX), and its analogues (paralytic shellfish toxins (PSTs)) produced by marine dinoflagellates. SxtA and SxtG are the most essential enzymes in STX biosynthesis. Previous studies investigated the abundance and subcellular localization (<em>i.e.</em>, chloroplasts) of SxtA in dinoflagellates using immunostaining. The present study characterized SxtG, and positive signals were detected in sister subclones of <em>Alexandrium catenella</em> (Group I) with extremely different levels of PSTs. Multiplex fluorescence immunostaining detection of a PST-positive subclone revealed co-localization of SxtA and SxtG, suggesting that SxtG localizes to chloroplasts. <em>In vitro</em> amidino-transfer from arginine to Int-A’, the first intermediate product in the biosynthesis, was presumed to be catalyzed by SxtG, and the reaction was established using crude extracts of PST-positive and negative <em>A. catenella</em> subclones. These analyses suggested that the PST-negative subclone expresses active SxtG but not SxtA. These findings support our hypothesis that decrease of SxtA leads to the loss of toxicity in the PST-negative subclone of <em>A. catenella</em>. Our results identified a key reaction that could enhance understanding of the biochemistry of STX biosynthesis in dinoflagellates.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"139 ","pages":"Article 102723"},"PeriodicalIF":5.5,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1568988324001562/pdfft?md5=fee179787431db79717ed90aee60f386&pid=1-s2.0-S1568988324001562-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142239857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperature-dependent akinete formation strategies of the harmful cyanobacterium Dolichospermum circinale","authors":"Chae-Hong Park ,&nbsp;Dae-Ryul Kwon ,&nbsp;Keonhee Kim ,&nbsp;Youn-Bo Sim ,&nbsp;Soon-Jin Hwang","doi":"10.1016/j.hal.2024.102722","DOIUrl":"10.1016/j.hal.2024.102722","url":null,"abstract":"<div><p>Cyanobacteria from the orders Nostocales and certain Stigonematales form akinetes, spore-like dormant cells that allow them to survive adverse environmental conditions. Temperature is known to be one of the key factors affecting akinete formation, but there is currently little known about akinete formation during cell growth over a wide range of temperature conditions and its relation to the overall survival strategy of cyanobacteria. Therefore, in the current study, we conducted a temperature-controlled experiment to analyze the akinete formation of a harmful cyanobacterium <em>Dolichospurmum circinale</em> using a growth chamber. We measured the concentration and size of both vegetative cells and different types of akinetes (free, attached, and empty type) under varying temperatures (5–25 °C). We also analyzed the buoyant ability and vertical migration velocity of trichomes along with changes in the volume of vegetative cells and akinetes. The total akinete concentration and ratio (number of akinetes to total number of cells) were both found to be higher at high temperatures (20–25°C) than they were at low temperatures (5–10°C) (p&lt;0.05). Meanwhile, the rate of formation of akinetes (both free and attached akinetes) was highest at low temperature (10 °C) and decreased with increasing temperature. The rate of empty akinete formation increased with increasing temperature and was highest at 25°C, indicating that most of the akinetes produced under high temperature conditions germinated. The change in vegetative cell size was proportional to the increase in the growth rate in response to increasing temperature (p&lt;0.05). At high temperature, vegetative cells exhibited positive buoyancy and higher vertical migration velocity, while at low temperature, they exhibited negative buoyancy and relatively low migration velocity. Akinete size was larger at low temperature than it was at high temperature. These findings suggest that akinetes play an important role in maintaining populations in the water column, with a link between akinete formation and germination during summer cyanobacteria blooms. This information is expected to contribute to a deeper understanding of the <em>D. circinale</em> life cycle.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"139 ","pages":"Article 102722"},"PeriodicalIF":5.5,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1568988324001550/pdfft?md5=750f603cbc5db879adfb904424002aef&pid=1-s2.0-S1568988324001550-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142164739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The green convergence: United States lakes are collectively moving toward a eutrophic state","authors":"Edna G. Fernandez-Figueroa ,&nbsp;Stephanie R. Rogers ,&nbsp;Matthew N. Waters ,&nbsp;Alan E. Wilson","doi":"10.1016/j.hal.2024.102721","DOIUrl":"10.1016/j.hal.2024.102721","url":null,"abstract":"<div><p>Nutrient enrichment and climate change promote algal blooms, leading to many lakes being characterized as eutrophic (i.e., green) worldwide. We examined recent eutrophication trends of freshwater lakes at a national scale by collating 32 years (1990–2021) of growing season (July-September) <em>in situ</em> chlorophyll-<em>a</em>, nutrient, transparency, and climate data for 1,082 lakes across 32 freshwater ecoregions in the United States. Based on chlorophyll-<em>a</em>, 78.2 % (427/546) of lakes initially exhibited eutrophic conditions and have remained eutrophic. Moreover, non-eutrophic lakes converged toward a eutrophic state, with oligotrophic (i.e., clear) or mesotrophic (i.e., moderately clear) lakes becoming greener, and hypereutrophic (i.e., very green) becoming less green. Optimized Hot Spot Analysis suggests lakes in the Appalachian Piedmont and Apalachicola freshwater ecoregions eutrophied more rapidly than other locations. Results suggest nutrient management targeting eutrophic lakes has hindered further degradation, but poor preventative management of clear lakes has led to their eutrophication.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"139 ","pages":"Article 102721"},"PeriodicalIF":5.5,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1568988324001549/pdfft?md5=c9f590cbb4747410140f7230d0b5becb&pid=1-s2.0-S1568988324001549-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142228856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Toxic effects of the emerging Alexandrium pseudogonyaulax (Dinophyceae) on multiple trophic levels of the pelagic food web","authors":"Kristof Möller ,&nbsp;Urban Tillmann ,&nbsp;Magdalena Pöchhacker ,&nbsp;Elisabeth Varga ,&nbsp;Bernd Krock ,&nbsp;Francesco Porreca ,&nbsp;Florian Koch ,&nbsp;Thomas M. Harris ,&nbsp;Cédric L. Meunier","doi":"10.1016/j.hal.2024.102705","DOIUrl":"10.1016/j.hal.2024.102705","url":null,"abstract":"<div><p>The dinoflagellate <em>Alexandrium pseudogonyaulax</em>, a harmful algal bloom species, is currently appearing in increasing frequency and abundance across Northern European waters, displacing other <em>Alexandrium</em> species. This mixotrophic alga produces goniodomins (GDs) and bioactive extracellular substances (BECs) that may pose a threat to coastal ecosystems and other marine resources. This study demonstrated the adverse effects of <em>A. pseudogonyaulax</em> on four marine trophic levels, including microalgae (<em>Rhodomonas salina</em>), microzooplankton (<em>Polykrikos kofoidii</em>) and mesozooplankton (<em>Acartia tonsa</em>), as well as fish gill cells (RTgill-W1, <em>Oncorhynchus mykiss</em>), ultimately leading to enhanced mortality and cell lysis. Furthermore, cell-free supernatants collected from <em>A. pseudogonyaulax</em> cultures caused complete loss of metabolic activity in the RTgill-W1 cell line, indicating ichthyotoxic properties, while all tested GDs were much less toxic. In addition, cell-free supernatants of <em>A. pseudogonyaulax</em> led to cell lysis of <em>R. salina</em>, while all tested GDs were non-lytic. Finally, reduced egg hatching rates of <em>A. tonsa</em> eggs exposed to cell-free supernatants of <em>A. pseudogonyaulax</em> and impaired mobility of <em>P. kofoidii</em> and <em>A. tonsa</em> exposed to <em>A. pseudogonyaulax</em> were also observed. Altogether, bioassay results suggest that the toxicity of <em>A. pseudogonyaulax</em> is mainly driven by BECs and not by GDs, although further research into factors modulating the lytic activity of <em>Alexandrium</em> spp. are needed.</p></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"138 ","pages":"Article 102705"},"PeriodicalIF":5.5,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1568988324001380/pdfft?md5=09b15ebc00116d8ada14edbd05d929d9&pid=1-s2.0-S1568988324001380-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142098057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}