Harmful Algae最新文献

{"title":"Control of cyanobacterial blooms with iron addition can favor stress-tolerant toxic species","authors":"Luis Aubriot ,&nbsp;Florencia Clivio ,&nbsp;Andrea Somma ,&nbsp;Elena Galvanese ,&nbsp;Sol Colombo ,&nbsp;Signe Haakonsson","doi":"10.1016/j.hal.2024.102784","DOIUrl":"10.1016/j.hal.2024.102784","url":null,"abstract":"<div><div>The control of internal phosphorus (P) load by in-lake measures has been the subject of decades of research. Although iron (Fe) is effective in precipitating P, it has been less tested due to its redox sensitivity. The effectiveness of Fe in controlling P availability and sinking cyanobacterial blooms contrasts to its function as a nutrient for phytoplankton growth. Both roles of Fe were tested in enclosures placed for 36 days in a shallow lake with a perennial cyanobacterial bloom, and in laboratory experiments with Fe-deficient <em>Raphidiopsis raciborskii</em>. Based on total P (TP) of lake water, we applied two doses of FeCl₃, corresponding to 30:1 (16 mg Fe L^-1) and 90:1 (47 mg Fe L^-1) (Fe:P molar), to cause P precipitation, and flocculation and sinking of cyanobacterial populations. Three enclosures per treatment and three without FeCl₃ additions (control) were used. The 90:1 treatment sank the main cyanobacterial biomass (50-fold) dominated by <em>Planktothrix agardhii</em>, with a significant decrease in turbidity, chlorophyll <em>a</em> and TP, without lasting decrease in pH, and achieved mesotrophic-like conditions. However, signs of recovery of <em>R. raciborskii</em> were detected between days 3 and 14. In laboratory experiments, Fe-deficient <em>R. raciborskii</em> MVCC19 grown under nitrate availability (+N) and N₂-fixation (–N) were exposed to five FeCl₃ concentrations from 0 to 17.9 (10:1) mg Fe L^-1 (Fe:P molar). A remarkable tolerance to high Fe was found at concentrations 7-fold higher than culture medium and decreased under –N. Also <em>R. raciborskii</em> stood low Fe levels in +N and exhibited higher Fe requirements under N₂-fixation. The increase in trichome length suggests resistance to the stressor, with shorter trichomes in –N. Therefore, effective management of <em>R. raciborskii</em> requires additional control of N in lakes. Our results point out the double role of Fe applications in which stress-tolerant species may become dominant under the reoligotrophication scenario.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102784"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144654","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":"Effects of the salinity on the growth, hemolytic activity, fatty acid content, and expression of polyketide synthase and fatty acid synthase genes of Amphidinium carterae (Dinophyceae)","authors":"Armando Mendoza-Flores ,&nbsp;Clara Elizabeth Galindo-Sánchez ,&nbsp;M. del Pilar Sánchez-Saavedra","doi":"10.1016/j.hal.2024.102788","DOIUrl":"10.1016/j.hal.2024.102788","url":null,"abstract":"<div><div>The benthic dinoflagellate <em>Amphidinium carterae</em> can produce fatty acids and polyketide compounds, such as amphidinols. Commonly, polyketides are produced by polyketides synthase (PKS), and fatty acids are produced by fatty acids synthase (FAS). The PKS and FAS genes in dinoflagellates share a common evolutionary history. This study aimed to investigate the effect of five salinities (20, 25, 30, 35, and 40 ‰) on growth, fatty acid content, hemolytic activity, and the expression of PKS and FAS genes. The results showed that low salinity (20 ‰) induces low growth in <em>A. carterae.</em> Cell size was affected by salinity, with a decrease in cell size with the salinity increase. The content of fatty acids and hemolytic compounds content increased at low salinities (20 and 25 ‰). The gene expression of the PKS genes was upregulated at high salinities (35 and 40 ‰) and downregulated at low salinities (20 and 25 ‰); FAS genes were downregulated at high (40 ‰) and low (20 ‰) salinities. The low growth rate at low salinity (20 ‰) and the high content of fatty acids and hemolytic compounds in low salinities (20 and 25 ‰) indicate that low salinities caused stress in this strain of <em>A. carterae.</em> The hemolytic activity at salinity of 20 ‰ probably due to a combinatory effect of high content of polyunsaturated fatty acids and amphidinols. To understand the relationship between gene expression and amphidinols biosynthesis requires the analysis of single-domain and multi-domain PKS.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102788"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143515","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":"Strain variability in toxin profiles and toxic potential of Dinophysis fortii populations from Southwestern and Northern Japanese coastal waters","authors":"Sirje Sildever ,&nbsp;Hajime Uchida ,&nbsp;Takanori Kuribayashi ,&nbsp;Masafumi Natsuike ,&nbsp;Yasufumi Hada ,&nbsp;Akira Miyazono ,&nbsp;Yuki Kosaka ,&nbsp;Natsuko Nakayama ,&nbsp;Wai Mun Lum ,&nbsp;Kazutaka Miyahara ,&nbsp;Kana Yamamoto ,&nbsp;Ryoji Matsushima ,&nbsp;Toshiyuki Suzuki ,&nbsp;Satoshi Nagai","doi":"10.1016/j.hal.2025.102803","DOIUrl":"10.1016/j.hal.2025.102803","url":null,"abstract":"<div><div>Harmful algal blooms are responsible for economic, societal, and health issues worldwide. In Japan, heterogeneity concerning diarrhetic shellfish poisoning (DSP) events has been reported, with most occurrences in the northern region. Although the toxin profile of <em>Dinophysis</em> cells from the DSP outbreaks has been investigated, no statistical comparison has been conducted on total toxin (particulate and released) production using cultured strains. A comparative toxin analysis was done based on &gt; 400 strains of <em>Dinophysis fortii</em> from Japan's southwestern and northern areas to investigate the heterogeneity in toxicity. Regardless of the origin, the toxin profile of all strains was dominated by PTX2. However, OA was the second most abundant toxin in the southwestern and DTX1 in the northern strains. For DTX1, the average concentrations in the north (330.54 ± 223.03 ng/mL) were significantly higher than in the southwest (5.85 ± 8.92 ng/mL). PTX2 also displayed significantly higher average concentrations in the north (384.51 ± 240.03 ng/mL) than in the southwest (122.66 ± 125.1 ng/mL). However, the northern strains had significantly lower levels of OA (6.74 ng/mL ± 13.53) than those from the southwest (34.86 ± 38.47 ng/mL). The total toxin yield in the northern strain cultures was about 56 times higher for DTX1, whereas OA content was 5 times lower, indicating significant differences in toxic potential in the strains from the two regions. The results of this toxin analysis contribute to the explanation of the geographical differences in DSP outbreaks associated with the blooms of <em>D. fortii</em> in Japan.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102803"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144165","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":"Unexpected shift from cyanobacterial to dinoflagellate dominance due to a summer drought","authors":"Sandra Rabow,&nbsp;Emma Johansson,&nbsp;Per Carlsson,&nbsp;Karin Rengefors","doi":"10.1016/j.hal.2024.102787","DOIUrl":"10.1016/j.hal.2024.102787","url":null,"abstract":"<div><div>The ruling paradigm is that future climate change scenarios will lead to an increase in the frequency, intensity, and duration of cyanobacterial blooms across the globe. It was therefore unexpected when, during an unusually warm and dry summer in southern Sweden in 2018, cyanobacteria did not dominate the phytoplankton community of the temperate Lake Vombsjön known for toxic cyanobacterial blooms. Instead, a potentially toxic dinoflagellate, <em>Naiadinium polonicum</em>, formed a large bloom and was dominant for the entire season. Dinoflagellates share important functional traits with cyanobacteria, but few studies have considered competition between dinoflagellates and cyanobacteria under future climate change scenarios. In order to understand the underlying factors leading to the <em>N. polonicum</em> bloom in 2018, we designed a study of Lake Vombsjön for an additional two years. When compared with subsequent years, 2018 was defined by an extended period of thermal stratification and hypoxia near the sediment surface. A significant positive relationship was also identified between <em>N. polonicum</em> biomass and both surface water temperature and soluble reactive phosphorus. We therefore suggest that the combination of higher temperatures and higher water column stability benefitted <em>N. polonicum</em> more so than cyanobacteria. Given that these factors are generally associated with cyanobacterial success, we conclude that freshwater phytoplankton community composition in temperate lakes can take different pathways in a warmer world.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102787"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144662","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":"Zooplankton grazing can facilitate and control the proliferation of harmful algal blooms caused by Dinophysis acuminata in NY, USA, estuaries","authors":"Megan Ladds,&nbsp;Christopher J. Gobler","doi":"10.1016/j.hal.2024.102789","DOIUrl":"10.1016/j.hal.2024.102789","url":null,"abstract":"<div><div>While harmful algal blooms (HABs) caused by the obligate-mixotroph, <em>Dinophysis acuminata</em>, have been associated with the ciliate, <em>Mesodinium rubrum,</em> the role of zooplankton grazing in the occurrence of these HABs has been under studied. Here, the dynamics of <em>D. acuminata</em> blooms were tracked within two NY, USA, harbors, over three years (2019–2021) during which grazing by native protozooplankton and introduced copepods (<em>Acartia tonsa</em>) was evaluated experimentally using an Imaging FlowCytobot (IFCB) to quantify plankton between 20 µm and 150µm. During each year, protoozooplankton grazing on <em>Dinophysis</em> was low during the bloom initiation period but exceeded cellular growth rates of <em>Dinophysis</em> during the peak bloom period, suggesting that a lack of grazing permitted bloom initiation but grazing onset facilitated bloom decline. The addition of juvenile <em>Acartia</em> increased <em>Dinophysis</em> growth rates in 10 of 14 experiments with differences being significant during three, bloom peak experiments. This finding suggests juvenile copepods can trigger a trophic cascade, potentially consuming <em>Dinophysis</em>-predators and releasing this HAB from grazer control. In contrast, adult <em>Acartia</em> and other mesozooplankton had minimal effects on <em>Dinophysis</em> densities suggesting that mesozooplankton did not directly impact blooms. Collectively, this study demonstrates that reduced grazing pressure at the onset of blooms facilitates bloom development, enhanced grazing during bloom peak can facilitate bloom decline, and that juvenile copepods can promote blooms via the induction of a trophic cascade.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"142 ","pages":"Article 102789"},"PeriodicalIF":5.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379149","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":"Higher sensitivity of microcystin-producing Microcystis to two algaecides compared to co-cultured non-microcystin producers","authors":"Ying Wei ,&nbsp;Yunni Gao ,&nbsp;Jing Wu ,&nbsp;Jing Dong ,&nbsp;Jingxiao Zhang ,&nbsp;Xiaofei Gao ,&nbsp;Huatao Yuan ,&nbsp;Xuejun Li ,&nbsp;Michele A. Burford","doi":"10.1016/j.hal.2025.102798","DOIUrl":"10.1016/j.hal.2025.102798","url":null,"abstract":"<div><div>Targeting and selectivity are essential for assessing the effectiveness of ecofriendly algaecides in controlling toxic cyanobacterial blooms. The dose- and time-dependent effects of hydrogen peroxide (H₂O₂), pyrogallol and their sustained-release microcapsules (HRM, PRM) on proportion of MC-producing cell numbers and genotypes of the co-existing MC- and non-MC-producing <em>Microcystis</em>, as well as microcystins (MCs) concentrations were investigated in the present study. Two MC-producing and two non-MC-producing <em>Microcystis</em> strains were used in mono- and co-culture test systems. The findings revealed that the MC-producing <em>Microcystis</em> strains were more sensitive to both forms of H₂O₂ and pyrogallol in comparison with the non-MC-producing strains. Inhibition of all <em>Microcystis</em> strains by H₂O₂ and pyrogallol was found to be dose- and time-dependent, with H₂O₂ exhibiting stronger effects. Additionally, both pure and granular forms of H₂O₂ and pyrogallol reduced the relative abundance of MC-producing genotypes in co-culture conditions, along with total MC concentrations. The HRM and PRM demonstrated more potent and prolonged effects than their pure forms, indicating they are optimal for targeted reduction of <em>Microcystis</em> bloom toxicity. Their long-term effects against different levels of MC-producing <em>Microcystis</em> in various environmental conditions need further investigation through large-scale outdoor experiments.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"143 ","pages":"Article 102798"},"PeriodicalIF":5.5,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395513","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":"Clearance rates and toxin accumulation by North Atlantic bivalves during harmful algal blooms caused by the dinoflagellate, Dinophysis acuminata, in NY, USA, estuaries","authors":"Bradley T. McGuire ,&nbsp;Marta P. Sanderson ,&nbsp;Juliette L. Smith ,&nbsp;Christopher J. Gobler","doi":"10.1016/j.hal.2024.102745","DOIUrl":"10.1016/j.hal.2024.102745","url":null,"abstract":"<div><div>Diarrhetic shellfish poisoning (DSP) is the intoxication syndrome derived from the consumption of bivalves that have accumulated toxins produced by algae such as <em>Dinophysis acuminata</em>, yet no study has examined the rate at which bivalves feed on this toxigenic species. During 2021 and 2022, the clearance rates (CR) of three commercially significant bivalve species native to the western North Atlantic (<em>Crassostrea virginica, Mercenaria mercenaria</em>, and <em>Mytilus edulis</em>) were quantified during exposure to <em>D. acuminata</em> blooms of varying densities (10² – 10⁵ cells L⁻¹) at three sites across New York (NY), USA. The same bivalve species were deployed at NY sites experiencing <em>Dinophysis</em> blooms to track accumulation and depuration rates of diarrhetic shellfish toxins (DSTs) and pectenotoxins (PTXs), toxins that are harmful to humans or shellfish, respectively. A native, non-commercial mussel species (<em>Geukensis demissa</em>) was also sampled in situ to quantify toxin accumulation. CR of <em>D. acuminata</em> were greater than chlorophyll-<em>a</em>-based-rates for all bivalves and clearance rates of <em>D. acuminata</em> by <em>C. virginica</em> (1.69 ± 1.34 L h⁻¹ g⁻¹) were significantly greater than those of <em>M. edulis</em> (0.46 ± 0.32 L h⁻¹ g⁻¹) and <em>M. mercenaria</em> (0.41 ± 0.24 L h⁻¹ g⁻¹; <em>p</em> &lt; 0.05). During a bloom event in 2021, <em>C. virginica</em> and <em>M. mercenaria</em> accumulated low levels of pectenotoxin-2 (PTX2), whereas during a more sustained bloom in 2022, <em>C. virginica, M. edulis</em>, and <em>G. demissa</em> accumulated combinations of DSTs (okadaic acid (OA), dinophysistoxin-1 (DTX1)), PTX2, and pectenotoxin-2 seco acid (PTX2sa) with <em>M. edulis</em> DST loads (265 ng OA + DTX1 g⁻¹ shellfish tissue) exceeding the FDA closure guideline (160 ng toxin g⁻¹) for three weeks. DST concentrations in <em>M. edulis</em> were significantly higher (<em>p</em> &lt; 0.05) than <em>C. virginica</em> and <em>M. mercenaria</em>, whereas PTX2 concentrations in <em>C. virginica</em> were significantly higher than in all other bivalves (<em>p</em> &lt; 0.05). PTX2sa loads in <em>M. edulis</em> and <em>C. virginica</em> were similar to each other and were significantly greater than PTX2 loads (<em>p</em> &lt; 0.05). Toxin accumulation efficiencies (TAEs) were higher for <em>M. edulis</em> than <em>C. virginica,</em> and TAEs for DSTs were higher than for PTX2 and PTX2sa in both species. The combination of rapid CR of <em>D. acuminata</em> observed in all bivalves, even at &gt;10⁵ cells L⁻¹, and the ability of bivalves such as <em>M. edulis</em> to rapidly accumulate high levels of DSTs demonstrate these HABs may represent a significant DSP threat in North America.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"141 ","pages":"Article 102745"},"PeriodicalIF":5.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142793109","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":"Divergent responses of an armored and an unarmored dinoflagellate to ocean acidification","authors":"Wei-Ping Zhang ,&nbsp;Shuo-Yu Zhang ,&nbsp;Yang Zhou ,&nbsp;Wen-Jing Sun ,&nbsp;Shu-Feng Zhang ,&nbsp;Jae-Seong Lee ,&nbsp;Minghua Wang ,&nbsp;Da-Zhi Wang","doi":"10.1016/j.hal.2024.102772","DOIUrl":"10.1016/j.hal.2024.102772","url":null,"abstract":"<div><div>Dinoflagellates, both armored and unarmored, with distinct cell wall difference, are being affected by elevated CO₂-induced ocean acidification (OA). However, their specific responses to OA are not well understood. In this study, we investigated the physiological and molecular response of the armored species <em>Prorocentrum obtusidens</em> and the unarmored species <em>Karenia mikimotoi</em> to OA over a 28-day period. The results show that the two species responded differently to OA. Cell growth rate, particulate organic carbon (POC) content, and the activities of C₄ pathway enzymes decreased in <em>P. obtusidens</em> under future acidified ocean condition (pH 7.8, 1000 μatm <em>p</em>CO₂), but the activities of carbonic anhydrase (CA), ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), and superoxide dismutase (SOD) increased. Whereas cell growth rate, contents of Chl <em>a</em> and PON, and SOD activity altered insignificantly in <em>K. mikimotoi</em>, but contents of POC and total carbohydrate, and the activity of RubisCO increased while the activities of CA and C₄ pathway enzymes decreased. Transcriptomic analysis indicates that genes associated with antioxidative response, heat shock protein, proteasome, signal transduction, ribosome, and pH regulation were up-regulated in <em>P. obtusidens</em> but down-regulated in <em>K. mikimotoi</em>. Notably, the synthesis of soluble organic matter (i.e., spermidine and trehalose) was enhanced in <em>K. mikimotoi</em>, thereby regulating intracellular pH and improving stress resistance. This study highlights the divergent response of the armored and unarmored dinoflagellates to OA, with the unarmored dinoflagellate exhibiting a higher ability to withstand this stressor. Therefore, caution should be exercised when predicting the behavior and the eventual fate of dinoflagellates in the future acidified ocean.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"141 ","pages":"Article 102772"},"PeriodicalIF":5.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746094","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":"Target-oriented element activation and functional group synthesis lead to high quality modified clay for Prorocentrum donghaiense control","authors":"Xihua Cao ,&nbsp;Mingjiao Wang ,&nbsp;Fan Liu ,&nbsp;Xiuxian Song ,&nbsp;Zhiming Yu","doi":"10.1016/j.hal.2024.102770","DOIUrl":"10.1016/j.hal.2024.102770","url":null,"abstract":"<div><div>Single source with series modifications (SSSM) is a new method to modify clay surfaces by activating clay mineral resources for harmful algal blooms control. In this study, the optimal preparation conditions for this method were obtained using response surface methodology. Based on the material analysis, an important way to obtain modified clay (MC) with the excellent <em>Prorocentrum donghaiense</em> removal performance was explored and the optimum preparation conditions were as follows: calcination temperature 750 °C, alkali neutralization pH 3.7 and clay supplementation ratio 1.3:1. Under these conditions, the calcination treatment can effectively activate the aluminum element in the clay lattice and obtain the largest amount of highly active Al ^IV and Al ^V, which are readily released from the lattice as activated aluminum. When the alkali neutralization pH was adjusted to 3.7, the activated aluminum was hydrolyzed and induced into highly positively charged polyhydroxyaluminum compounds. The supplemented kaolin increased the yield of the MC product by surface convergence of the activated aluminum in the system. As a result, the optimized MC can form large particle size flocs with good regeneration and stability during the algal removal process, which greatly improved its ability to coagulate and sediment algal cells. Overall, the MC prepared by the SSSM method achieved high algal removal efficiency through targeted element activation and functional group shaping.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"141 ","pages":"Article 102770"},"PeriodicalIF":5.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746093","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":"Metabolic transformation of paralytic shellfish toxins in the mussel Mytilus galloprovincialis under different exposure modes","authors":"Guanchao Zheng ,&nbsp;Hanyu Che ,&nbsp;Haiyan Wu ,&nbsp;Yuxiang Deng ,&nbsp;Mengmeng Guo ,&nbsp;Jixing Peng ,&nbsp;Qianqian Geng ,&nbsp;Zhijun Tan","doi":"10.1016/j.hal.2024.102771","DOIUrl":"10.1016/j.hal.2024.102771","url":null,"abstract":"<div><div><em>Gymnodinium catenatum</em> is a widely distributed toxic marine dinoflagellate that produces paralytic shellfish toxins (PSTs). It is prone to causing algal blooms and poses a serious threat to the shellfish industry and human health. Previous studies have shown that when algal blooms occur, shellfish can accumulate PSTs in their bodies due to filtration. In this study, mussels (<em>Mytilus galloprovincialis</em>) were fed with <em>G. catenatum</em> at different fixed or varied cell density over time, with the latter designed to mimic the changes in algal cell density over time in the wild. The PST concentration in the mussels was positively correlated with the number of algal cells, and PSTs rapidly accumulated in the mussels under both feeding modes. Compared with constant feeding in the low feeding group, variable cell density feeding over time was more conducive to the accumulation of PSTs in <em>M. galloprovincialis</em>. An obvious toxin transformation process was also detected in the mussels, which transformed the less toxic gonyautoxins-5 and -6 and <em>N</em>-sulfocarbamoyl gonyautoxin-3 ingested from <em>G. catenatum</em> into the more toxic decarbamoyl gonyautoxin-2, decarbamoyl saxitoxin, and decarbamoyl neosaxitoxin. The ratio of epimer pairs, α:β, tended to stabilize when the toxin concentration was highest, and it increased rapidly after mussels stopped consuming toxigenic algae. These results suggested that the formation of α-stable toxoids mainly occurred during the process of toxin depuration. Toxins were also transformed from low to high toxicity, and α-stable toxoids were formed mainly in the hepatopancreas. These results provided basic data for better understanding of the laws governing metabolic transformation of PSTs in bivalves during algal blooms.</div></div>","PeriodicalId":12897,"journal":{"name":"Harmful Algae","volume":"141 ","pages":"Article 102771"},"PeriodicalIF":5.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745988","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}