Harmful Algae最新文献

Divergent responses of an armored and an unarmored dinoflagellate to ocean acidification 甲壳鞭毛虫与非甲壳鞭毛虫对海洋酸化的不同反应

IF 5.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2024-11-26 DOI: 10.1016/j.hal.2024.102772

Wei-Ping Zhang , Shuo-Yu Zhang , Yang Zhou , Wen-Jing Sun , Shu-Feng Zhang , Jae-Seong Lee , Minghua Wang , Da-Zhi Wang

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 Prorocentrum obtusidens and the unarmored species Karenia mikimotoi 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 P. obtusidens under future acidified ocean condition (pH 7.8, 1000 μatm pCO₂), 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 a and PON, and SOD activity altered insignificantly in K. mikimotoi, 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 P. obtusidens but down-regulated in K. mikimotoi. Notably, the synthesis of soluble organic matter (i.e., spermidine and trehalose) was enhanced in K. mikimotoi, 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.

甲壳和无甲壳鞭毛藻细胞壁差异明显，正受到co2引起的海洋酸化（OA）升高的影响。然而，他们对OA的具体反应尚不清楚。在这项研究中，我们研究了在28天的时间里，有甲种原心菌（proorocentrum obtusidens）和无甲种mikimotokarenia对OA的生理和分子反应。结果表明，两种植物对OA的反应不同。在未来酸化的海洋环境（pH 7.8, 1000 μatm pCO2）下，P. obtusidens的细胞生长速率、颗粒有机碳（POC）含量和C4途径酶活性降低，但碳酸酐酶（CA）、核酮糖-1,5-二磷酸羧化酶/加氧酶（RubisCO）和超氧化物歧化酶（SOD）活性升高。细胞生长速率、Chl a和PON含量以及SOD活性变化不显著，但POC和总碳水化合物含量以及RubisCO活性升高，CA和C4途径酶活性降低。转录组学分析表明，与抗氧化反应、热休克蛋白、蛋白酶体、信号转导、核糖体和pH调节相关的基因在黑齿冬中上调，而在mikimotoi中下调。值得注意的是，mikimotoi提高了可溶性有机物（即亚精胺和海藻糖）的合成，从而调节了细胞内pH值，提高了抗逆性。这项研究强调了甲壳鞭毛虫和未甲壳鞭毛虫对OA的不同反应，未甲壳鞭毛虫表现出更高的抵抗这种应激源的能力。因此，在预测未来酸化海洋中鞭毛藻的行为和最终命运时，应谨慎行事。

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引用次数: 0

Target-oriented element activation and functional group synthesis lead to high quality modified clay for Prorocentrum donghaiense control 目标导向元素活化和官能团合成可获得高质量的东海原心控制改性粘土

IF 5.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2024-11-26 DOI: 10.1016/j.hal.2024.102770

Xihua Cao , Mingjiao Wang , Fan Liu , Xiuxian Song , Zhiming Yu

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 Prorocentrum donghaiense 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.

单源串联修饰是通过激活黏土矿物资源对黏土矿物表面进行修饰以控制有害藻华的新方法。在本研究中，利用响应面法获得了该方法的最佳制备条件。在材料分析的基础上，探索了获得具有优异东海原心菌去除性能的改性粘土（MC）的重要途径，最佳制备条件为：煅烧温度750℃，碱中和pH 3.7，粘土添加比1.3:1。在此条件下，煅烧处理能有效活化粘土晶格中的铝元素，获得最多的高活性Al IV和Al V，它们很容易以活性铝的形式从晶格中释放出来。当碱中和pH调至3.7时，活化铝水解并诱导成高正电荷的多羟基铝化合物。添加高岭土后，活性铝在体系中的表面聚合，提高了MC产品的收率。结果表明，优化后的MC在除藻过程中可以形成大粒径的絮凝体，且再生稳定性好，大大提高了其对藻细胞的凝结和沉淀能力。综上所述，SSSM法制备的MC通过靶向元件活化和官能团塑造实现了较高的除藻效率。

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引用次数: 0

Metabolic transformation of paralytic shellfish toxins in the mussel Mytilus galloprovincialis under different exposure modes 不同暴露方式下麻痹贝类毒素在褐贻贝体内的代谢转化

IF 5.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2024-11-26 DOI: 10.1016/j.hal.2024.102771

Guanchao Zheng , Hanyu Che , Haiyan Wu , Yuxiang Deng , Mengmeng Guo , Jixing Peng , Qianqian Geng , Zhijun Tan

Gymnodinium catenatum 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 (Mytilus galloprovincialis) were fed with G. catenatum 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 M. galloprovincialis. An obvious toxin transformation process was also detected in the mussels, which transformed the less toxic gonyautoxins-5 and -6 and N-sulfocarbamoyl gonyautoxin-3 ingested from G. catenatum 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.

裸子鞭毛虫是一种广泛分布的有毒海洋鞭毛虫，产生麻痹性贝类毒素（PSTs）。它容易引起藻华，对贝类产业和人类健康构成严重威胁。先前的研究表明，当藻华发生时，贝类可以通过过滤在体内积累pst。在这项研究中，贻贝（Mytilus galloprovincialis）在不同的固定或变化的细胞密度下喂食G. catenatum，后者的设计是为了模仿野生藻类细胞密度随时间的变化。贻贝体内PST浓度与藻细胞数量呈正相关，在两种摄食方式下，PST在贻贝体内迅速积累。与低摄食组的恒定摄食相比，随时间变化的细胞密度摄食更有利于百毒杆菌PSTs的积累。在贻贝体内也检测到明显的毒素转化过程，将从螯虾中摄取的毒性较小的gonyautooxin -5、-6和N-sulfocarbamoyl gonyautotoxin -3转化为毒性较大的decarbamoyl gonyautotoxin -2、decarbamoyl saxitoxin和decarbamoyl neosaitoxin。当毒素浓度最高时，外显体对α:β的比值趋于稳定，在贻贝停止食用产毒藻类后，外显体对α:β的比值迅速增加。这些结果表明，α-稳定型类毒素的形成主要发生在毒素净化过程中。毒素也由低毒性向高毒性转化，α-稳定的类毒素主要在肝胰脏形成。这些结果为更好地理解藻华期间双壳类PSTs代谢转化规律提供了基础数据。

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引用次数: 0

Intraspecific genetic diversity with unrestricted gene flow in the domoic acid-producing diatom Nitzschia navis-varingica (Bacillariophyceae) from the Western Pacific 西太平洋产软骨藻酸硅藻耐氏硅藻（硅藻科）种内基因流动不受限制的遗传多样性

IF 5.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2024-11-26 DOI: 10.1016/j.hal.2024.102769

Suh Nih Tan , Yuichi Kotaki , Sing Tung Teng , Hong Chang Lim , Chunlei Gao , Nina Lundholm , Matthias Wolf , Haifeng Gu , Po Teen Lim , Chui Pin Leaw

The benthic pennate diatom Nitzschia navis-varingica, known for producing domoic acid (DA) and its isomers, is widely distributed in the Western Pacific (WP) region. To investigate the genetic differentiation and gene flow patterns among the populations in the WP, the genetic diversity of 354 strains of N. navis-varingica was analysed using two nuclear-encoded rDNA loci: the large subunit rDNA (LSU rDNA) and the internal transcribed spacer 2 (ITS2). Frustule morphology of each strain was examined by TEM. The LSU rDNA phylogeny revealed a monophyletic lineage encompassing all strains, with sequence divergences of <0.9 %. Phylogenetic and population genetic analyses of ITS2 identified eight distinct clades (designated as Groups A to H) with moderate to high genetic heterogeneity (0.5–19.7 %). The low genetic differentiations between the geographically separated populations (pairwise F_ST of <0.03) suggested high gene flow and lack of spatial genetic structuring. Molecular clock analysis of the ITS2 phylogeny traced the evolutionary history of N. navis-varingica to the Eocene Epoch, and the split between clades likely occurred from the mid-Miocene to Pleistocene Epochs (10.8–1.2 Ma). The population dispersal in the WP were likely influenced by historical events like the Quarternary glacial cycles during the period, contributing to its homogenous distributions in the region.

底栖pennate硅藻Nitzschia navis-varingica以生产软骨藻酸（DA）及其异构体而闻名，广泛分布于西太平洋（WP）地区。为了研究湿地内不同居群间的遗传分化和基因流动模式，利用大亚基rDNA （LSU rDNA）和内转录间隔区2 （ITS2）两个核编码rDNA位点，对354株褐花南芥的遗传多样性进行了分析。用透射电镜观察各菌株的结晶形态。LSU rDNA系统发育揭示了包含所有菌株的单系谱系，序列差异为0.9%。通过对ITS2的系统发育和群体遗传分析，鉴定出8个不同的进化支（称为A ~ H群），具有中等到高度的遗传异质性（0.5 ~ 19.7%）。地理分离居群间的遗传分化程度较低（两两FST为0.03），表明居群间存在较大的基因流动，缺乏空间遗传结构。分子钟分析将navis-varingica的进化历史追溯至始新世，分支之间的分裂可能发生在中新世中期至更新世（10.8-1.2 Ma）。在此期间，第四纪冰期旋回等历史事件可能影响了该地区的种群分布，从而导致了该地区种群分布的均匀性。

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引用次数: 0

Microcystins bioaccumulate but do not biomagnify in an experimental aquatic food chain 微囊藻毒素在实验水生食物链中生物积累但不生物放大

IF 5.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2024-11-23 DOI: 10.1016/j.hal.2024.102768

Dani Glidewell, Jessica E. Beyer, K. David Hambright

Microcystins—common hepatotoxins produced by cyanobacteria—have been detected in a wide range of organisms, though research examining the trophic transfer of microcystins and whether microcystins bioaccumulate or biomagnify in food webs has generated contradictory results. Here, we explored the trophic transfer of microcystins from the herbivorous water flea, Daphnia pulex, to the predatory larvae of a damselfly, Enallagma sp. We tested the hypotheses that microcystins transfer from the tissue of herbivorus zooplankton to that of predatory invertebrates and that these toxins biomagnify across trophic levels. We also assessed the relative contribution of toxin transfer from the gut and tissue of Daphnia pulex to Enallagma sp. We found that microcystins are effectively sequestered in the tissue of Daphnia pulex, and that these sequestered toxins are then transferred to the tissue of Enallagma sp. The contribution of gut contents to toxin transfer was negligible. Contrary to the pattern predicted by biomagnification, we found that the concentration of microcystins decreased with increasing trophic levels. Our results support the hypothesis that microcystins can be transferred trophically, but do not support the hypothesis that microcystins biomagnify from lower to higher trophic levels. Conversly, we observe biodilution in this system. These results have consequences for the impact of microcystins across trophic levels in a changing world with increasing intensity and duration of harmful algal blooms.

微囊藻毒素——由蓝藻细菌产生的常见肝毒素——已经在广泛的生物体中被检测到，尽管研究微囊藻毒素的营养转移以及微囊藻毒素是否在食物网中生物积累或生物放大已经产生了相互矛盾的结果。在这里，我们探索了微囊藻毒素从食草水蚤（Daphnia pulex）到豆蝇（Enallagma sp.）的掠食性幼虫的营养转移。我们验证了微囊藻毒素从食草浮游动物组织转移到掠食性无脊椎动物组织的假设，以及这些毒素在营养水平上的生物放大。我们还评估了毒素从水蚤的肠道和组织转移到蛭形线虫的相对贡献。我们发现微囊藻毒素有效地隔离在水蚤的组织中，这些隔离的毒素随后被转移到蛭形线虫的组织中。肠道内容物对毒素转移的贡献可以忽略不计。与生物放大预测的模式相反，我们发现微囊藻毒素的浓度随着营养水平的增加而下降。我们的研究结果支持微囊藻毒素可以营养转移的假设，但不支持微囊藻毒素从低营养水平向高营养水平生物放大的假设。相反，我们在这个系统中观察到生物稀释。随着有害藻华的强度和持续时间不断增加，这些结果对微囊藻毒素在营养水平上的影响产生了影响。

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引用次数: 0

Gonyaulax montresoriae sp. nov. (Dinophyceae) from the Adriatic Sea produces predominantly yessotoxin 来自亚得里亚海的 Gonyaulax montresoriae sp.

IF 5.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2024-11-23 DOI: 10.1016/j.hal.2024.102761

Shuning Huang , Kenneth Neil Mertens , Amélie Derrien , Ophélie David , Hyeon Ho Shin , Zhun Li , Xiuyun Cao , Marina Cabrini , Daniela Klisarova , Haifeng Gu

Yessotoxin is one of the shellfish toxins leading to mussel farm closures in the Adriatic Sea of Italy. Two putative Gonyaulax spinifera strains GSA0501 and GSA0602 are known as yessotoxins producers, but their identities have remained elusive since 2005. To address this gap, we established five Gonyaulax strains by incubating sediments from the Adriatic Sea and subsequently isolating single cells. Both cyst and theca morphology were examined using light and scanning electron microscopy. In addition, LSU and/or SSU rRNA gene sequences were obtained for all strains. Two strains produce cysts resembling Spiniferites mirabilis and one strain was related to S. scabratus. The other two strains are described as Gonyaulax montresoriae sp. nov., characterized by a high cingular displacement and overhang, along with two unequal antapical spines. Cysts of G. montresoriae are pear-shaped, showing a smooth surface and exclusively gonal processes with perforations at the base, the latter similar to S. lazus. LSU rRNA gene sequence comparison suggests that the G. spinifera strain GSA0501 isolated from the Adriatic Sea in 2005 should also be identified as G. montresoriae. Maximum likelihood and Bayesian inference analyses based on LSU and SSU rRNA gene sequences reveal that G. montresoriae is monophyletic, and close to several toxic strains of presumable Gonyaulax spinifera from the Adriatic Sea and New Zealand, whose taxonomic positions are uncertain. One strain of G. montresoriae was examined for yessotoxin production using LC-MS/MS, and found to produce predominantly yessotoxin at a concentration of 3.0 pg cell^-1. Our results highlight the rich diversity and risks associated with Gonyaulax species in the Mediterranean Sea.

贻贝毒素是导致意大利亚得里亚海贻贝养殖场关闭的贝类毒素之一。两种推定的 Gonyaulax spinifera 菌株 GSA0501 和 GSA0602 是已知的叶索毒素生产者，但自 2005 年以来，它们的身份一直难以确定。为了填补这一空白，我们对亚得里亚海的沉积物进行培养，随后分离出单细胞，建立了五株 Gonyaulax 菌株。我们使用光镜和扫描电子显微镜对囊肿和囊口形态进行了检测。此外，还获得了所有菌株的 LSU 和/或 SSU rRNA 基因序列。两株菌株产生的包囊与奇异棘皮动物（Spiniferites mirabilis）相似，一株菌株与疥棘皮动物（S. scabratus）有亲缘关系。另外两株被描述为 Gonyaulax montresoriae sp.G. montresoriae 的孢子囊呈梨形，表面光滑，基部仅有带孔的子房突起，后者与 S. lazus 相似。LSU rRNA 基因序列比较表明，2005 年从亚得里亚海分离出的 G. spinifera 菌株 GSA0501 也应被确定为 G. montresoriae。基于 LSU 和 SSU rRNA 基因序列的最大似然法和贝叶斯推断分析表明，G. montresoriae 是单系的，与来自亚得里亚海和新西兰的几株推测为 Gonyaulax spinifera 的有毒菌株很接近，而这些菌株的分类位置尚不确定。我们使用 LC-MS/MS 对一株 G. montresoriae 进行了检查，以确定其是否产生贻贝毒素，结果发现在 3.0 pg cell-1 的浓度下，它主要产生贻贝毒素。我们的研究结果突显了地中海中 Gonyaulax 物种的丰富多样性和相关风险。

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引用次数: 0

Influence of nitrate and salinity on growth and toxin production of Prymnesium parvum 硝酸盐和盐度对副栉水母的生长和毒素产生的影响

IF 5.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2024-11-18 DOI: 10.1016/j.hal.2024.102760

Wenhui Yan , Guixiang Wang , Ying Ji , Jiangbing Qiu , Chengxu Zhou , Aifeng Li

Fish-killing events caused by haptophyte Prymnesium parvum have been reported in aquatic environments worldwide. This haptophyte could produce diverse prymnesins (PRMs) that harm to aquatic organisms like fishes. In this study, the components of prymnesins in the strain of P. parvum (NMBjih029) isolated from the coast of Ningbo city, China, were elucidated by a high-resolution mass spectrometer (HRMS), and the influence of nitrate levels and salinity on growth and toxin production of P. parvum were also explored. Results showed that the P. parvum produced C-type prymnesins with structure variations in saturation, chlorination, and sugar modifications. The growth and toxin production were significantly affected by nitrate levels in the batch cultures. At the lowest level of nitrate (N:P = 4:1), growth of P. parvum was inhibited but toxin quotas per cell increased up to approximately 4 times of that in control group (N:P = 16:1) during the exponential growth stage. Growth of P. parvum was not obviously affected by different salinities, but the biosynthesis of prymnesins increased with decreasing salinity from 32 to 14 in the culture media. The proportion of high chlorination of prymnesins (tetrachloride) increased in P. parvum under nitrogen limitation stress and low salinity. And the toxin quotas per cell also markedly increased with the extension of culture period in P. parvum under nitrogen limitation and different salinity conditions. This study provides some important cues for toxin profile and environmental impacts on the biosynthesis of prymnesins in the strain of P. parvum isolated from Chinese aquatic environments.

据报道，在世界各地的水生环境中都发生过由副栉水母（Prymnesium parvum）引起的杀鱼事件。这种隐翅虫可产生多种胰蛋白酶（PRMs），对鱼类等水生生物造成危害。本研究利用高分辨质谱仪（HRMS）阐明了从中国宁波沿海分离到的噬菌体菌株（NMBjih029）中的胰蛋白酶成分，并探讨了硝酸盐含量和盐度对噬菌体生长和毒素产生的影响。结果表明，副噬菌体产生的 C 型胰蛋白酶在饱和度、氯化和糖修饰方面存在结构变化。在批次培养过程中，生长和毒素产量受硝酸盐水平的显著影响。在最低硝酸盐水平（N:P = 4:1）下，副噬菌体的生长受到抑制，但在指数生长阶段，每个细胞的毒素配额增加到对照组（N:P = 16:1）的约 4 倍。不同盐度对副噬菌体的生长没有明显影响，但随着培养基盐度从 32 度降低到 14 度，胰蛋白酶的生物合成增加。在氮限制胁迫和低盐度条件下，副褐藻中高氯化的胰蛋白酶（四氯化碳）比例增加。在氮限制和不同盐度条件下，随着培养时间的延长，每个细胞的毒素配额也明显增加。本研究为了解从中国水生环境中分离出的副栉水母菌株的毒素特征以及环境对其胰蛋白酶生物合成的影响提供了一些重要线索。

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引用次数: 0

Species and genetic diversity of notorious dinoflagellates Pfiesteria piscicida, Luciella masanensis, and relatives in marine sediments of China 中国海洋沉积物中臭名昭著的甲藻 Pfiesteria piscicida、Luciella masanensis 及其近缘种的种类和遗传多样性

IF 5.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2024-11-15 DOI: 10.1016/j.hal.2024.102746

Zhe Tao , Xiaohan Liu , Xiaoying Song , Yunyan Deng , Lixia Shang , Zhaoyang Chai , Zhangxi Hu , Yuyang Liu , Ying Zhong Tang

The dinoflagellate genus Pfiesteria, encompassing Pfiesteria piscicida and P. shumwayae, became a hot topic in HABs research in the early 2000s due to numerous but controversial reports regarding life cycle and toxicity. While Pfiesteria presence has been reported from all continents, surprisingly, there has been no documented presence in China to date. Here, we report our findings on the presence, species, and genetic diversity of Pfiesteria and its phylogenetic relatives (particularly Luciella masanensis) using a combined approach. First, we demonstrated the presence of P. piscicida and L. masanensis using metabarcoding analysis of >320 sediment samples. Pfiesteria piscicida was identified in 32 sampling sites across all four seas of China, with rDNA sequences exhibiting considerable differences from the type strain (up to 3.83 %), while Luciella masanensis presented in 212 sites from all four seas and included only ribotypes 1 and 3 among the four known ribotypes. Second, based on the metabarcoding detections, our application of FISH with species-specific probes and subsequent single-cyst PCR sequencing to the “positive” sediments confirmed, both morphologically and molecularly, the existence of P. piscicida and L. masanensis cysts in the sediments. Finally, individual cysts were isolated using the sodium polytungstate protocol and sequenced targeting 28S rDNA D1–D6 domains. Phylogenetic analysis revealed that 35 resting cysts were relatives of Pfiesteria, likely belonging to either new species or novel genera and family because they formed at least two distinct clades in the phylogenetic tree. Pfiesteria shumwayae was not detected from any sample, suggesting its absence in Chinese waters. We believe this work provides important factual basis for the global biogeography of these species and future HABs monitoring of in China.

本世纪初，由 Pfiesteria piscicida 和 P. shumwayae 组成的甲藻属 Pfiesteria 成为有害藻华研究的热门话题，因为有关其生命周期和毒性的报告很多，但却存在争议。虽然各大洲都有关于 Pfiesteria 存在的报道，但令人惊讶的是，迄今为止还没有关于中国存在 Pfiesteria 的记录。在此，我们采用一种综合方法，报告了我们对 Pfiesteria 及其系统发育近缘种（尤其是 Masanensis Luciella）的存在、种类和遗传多样性的研究结果。首先，我们通过对 320 份沉积物样本进行代谢编码分析，证明了 P. piscicida 和 L. masanensis 的存在。Pfiesteria piscicida在中国所有四个海域的32个采样点被鉴定，其rDNA序列与模式株有相当大的差异（高达3.83%）；而Luciella masanensis在所有四个海域的212个采样点被鉴定，在已知的四个核型中仅包括核型1和核型3。其次，在元条码检测的基础上，我们对 "阳性 "沉积物使用物种特异性探针进行 FISH 检测，并随后进行单囊蚴 PCR 测序，从形态学和分子学上证实了 P. piscicida 和 L. masanensis 囊蚴在沉积物中的存在。最后，使用多钨酸钠方案分离了单个囊蚴，并对 28S rDNA D1-D6 域进行了测序。系统进化分析表明，35 个静止孢囊是 Pfiesteria 的近亲，很可能属于新种或新属和新科，因为它们在系统进化树中至少形成了两个不同的支系。在所有样本中都没有检测到 Pfiesteria shumwayae，这表明中国水域中没有这种细菌。我们相信，这项工作为这些物种的全球生物地理学和中国未来的有害藻华监测提供了重要的事实依据。

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引用次数: 0

Molecular investigation of harmful cyanobacteria reveals hidden risks and niche partitioning in Kenyan Lakes 有害蓝藻的分子研究揭示了肯尼亚湖泊中隐藏的风险和生态位划分

IF 5.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2024-11-10 DOI: 10.1016/j.hal.2024.102757

Brittany N. Zepernick , Lauren N. Hart , Emily E. Chase , Kaela E. Natwora , Julia A. Obuya , Mark Olokotum , Katelyn A. Houghton , E. Anders Kiledal

Despite the global expansion of cyanobacterial harmful algal blooms (cHABs), research is biased to temperate systems within the global north, such as the Laurentian Great Lakes. This lack of diversity represents a significant gap in the field and jeopardizes the health of those who reside along at-risk watersheds in the global south. The African Great Lake, Lake Victoria, is understudied despite serving as the second largest lake by surface area and demonstrating year-round cHABs. Here, we address this knowledge gap by performing a molecular survey of cHAB communities in three anthropogenically and ecologically important freshwater systems of Victoria's Kenyan watershed: Winam Gulf (Lake Victoria), Lake Simbi and Lake Naivasha. We identified a bloom of non-toxic Dolichospermum and toxic Microcystis in the Winam Gulf, with data suggesting sulfur limitation shapes competition dynamics between these two bloom-formers. Though we did not detect a bloom in Naivasha, it contained the largest diversity of cHAB genera amongst the three lakes. In turn, our results indicated methane metabolism may allow non-toxic picoplankton to outcompete cHAB genera, while suggesting Synechococcus spp. serves as a methane source and sink in this system. Lake Simbi exhibited a non-toxic Limnospira bloom at the time of sampling with very low abundances of cHAB genera present. Subsequently, these results were employed to design a cHAB screening and risk assessment framework for local stakeholders. Cumulatively, this work serves to increase cHAB research efforts on the international scale while serving as an impetus for cHAB monitoring on the local scale.

尽管蓝藻有害藻华（cHABs）在全球范围内蔓延，但研究却偏重于全球北部的温带系统，例如劳伦伦五大湖。这种多样性的缺乏是该领域的一个重大空白，并危及全球南部高危流域居民的健康。非洲大湖维多利亚湖（Lake Victoria）尽管是面积第二大的湖泊，而且全年都会发生 cHABs，但对它的研究却很不够。在此，我们通过对维多利亚湖肯尼亚流域三个具有重要人类和生态意义的淡水系统中的 cHAB 群落进行分子调查，填补了这一知识空白：维纳姆湾（维多利亚湖）、辛比湖和奈瓦沙湖。我们在维纳姆湾发现了无毒的多利可囊藻（Dolichospermum）和有毒的微囊藻（Microcystis）的藻华，数据表明硫限制影响了这两种藻华形成者之间的竞争态势。虽然我们在奈瓦沙没有发现藻华，但该湖中的 cHAB 属的多样性在三个湖泊中是最高的。反过来，我们的研究结果表明，甲烷代谢可能会使无毒的浮游微藻超越 cHAB 藻属，同时表明 Synechococcus spp.是该系统中的甲烷源和汇。取样时，Simbi 湖呈现出无毒的褐藻藻华，cHAB 属的丰度非常低。随后，利用这些结果为当地利益相关者设计了一个 cHAB 筛选和风险评估框架。总之，这项工作有助于加强国际范围内的 cHAB 研究工作，同时推动地方范围内的 cHAB 监测工作。

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引用次数: 0

Effects of temperature, salinity and CO2 concentration on growth and toxin production of the harmful algal bloom species Alexandrium pseudogonyaulax (Dinophyceae) from the Danish Limfjord 温度、盐度和二氧化碳浓度对丹麦林峡湾有害藻华物种 Alexandrium pseudogonyaulax（蝶形花科）的生长和毒素产生的影响

IF 5.5 1区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Harmful Algae

Pub Date : 2024-11-09 DOI: 10.1016/j.hal.2024.102756

Simon Tulatz , Bernd Krock , Urban Tillmann , Cédric Leo Meunier

The marine dinoflagellate Alexandrium pseudogonyaulax is a widely distributed Harmful Algal Bloom (HAB) species that produces the macrocyclic polyketide goniodomin A (GDA). Occurrences in northern European waters are increasing and a spreading of the species along a salinity gradient into the Baltic Sea has been observed. As GDA is suspected to lead to invertebrate mortality, the spreading is of concern for the environment and possibly human health. In order to assess the potential of A. pseudogonyaulax to adapt to the environmental conditions in the Baltic Sea and the risk of future harmful blooms of that species, we quantified the influence of bottom-up factors on the growth and toxin content of three strains of A. pseudogonyaulax from the Danish Limfjord. Specifically, we exposed these strains to salinities ranging from 5 to 50, temperatures in the range of 10 – 30 °C and to three different CO₂ concentrations of 250, 400 and 1000 µatm. All strains tolerated a broad range of salinities and temperatures, resulting in positive growth rates ranging from 0.06 to 0.33 d^-1 between temperatures of 12 and 27 °C and between salinities of 10 and 40. The highest cell quotas of GDA were measured at low temperatures. For two strains, GDA amounts were almost unaffected by salinity, while the cell quota of the third strain decreased about 20-fold when salinity increased above 30. Different CO₂ concentrations had no effect on growth or GDA production. In summary, these findings show a high ecological tolerance towards a wide range of temperatures and salinities of the Limfjord population of A. pseudogonyaulax, together with distinct intraspecific physiological differences within the population. Our results also suggest that a further spreading into the Baltic Sea might be possible.

海洋甲藻亚历山大藻（Alexandrium pseudogonyaulax）是一种广泛分布的有害藻华（HAB）物种，能产生大环多酮类物质贡碘明 A（GDA）。该物种在北欧水域的出现率正在上升，并已观察到其沿着盐度梯度向波罗的海扩散。由于 GDA 被怀疑会导致无脊椎动物死亡，其扩散对环境乃至人类健康都会造成影响。为了评估 A. pseudogonyaulax 适应波罗的海环境条件的潜力以及该物种未来发生有害藻华的风险，我们量化了自下而上的因素对来自丹麦林峡湾的三株 A. pseudogonyaulax 的生长和毒素含量的影响。具体来说，我们将这些菌株置于盐度为 5 至 50、温度为 10 至 30 °C、二氧化碳浓度为 250、400 和 1000 µatm 的三种不同环境中。所有菌株都能耐受较大范围的盐度和温度，在温度为 12 至 27 °C、盐度为 10 至 40 °C时，生长率为 0.06 至 0.33 d-1。在低温条件下测得的 GDA 细胞配额最高。两个菌株的 GDA 量几乎不受盐度影响，而第三个菌株的细胞配额在盐度超过 30 时减少了约 20 倍。不同浓度的二氧化碳对生长和 GDA 产量没有影响。总之，这些研究结果表明，林峡湾伪尾柱虫种群对多种温度和盐度具有很强的生态耐受性，而且种群内部存在明显的种内生理差异。我们的研究结果还表明，该种群有可能进一步向波罗的海扩散。

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引用次数: 0