Alfred Wegener Institute, Am Handelshafen 12, D-27570 Bremerhaven, Germany.
Senckenberg Research Institute and Natural History Museum, Senckenberganlage 25, D-60325 Frankfurt a.M., Germany.
Harmful Algae. 2016 May;55:85-96. doi: 10.1016/j.hal.2016.02.004. Epub 2016 Mar 2.
Harmful algal blooms are mainly caused by marine dinoflagellates and are known to produce potent toxins that may affect the ecosystem, human activities and health. Such events have increased in frequency and intensity worldwide in the past decades. Numerous processes involved in Global Change are amplified in the Arctic, but little is known about species specific responses of arctic dinoflagellates. The aim of this work was to perform an exhaustive morphological, phylogenetical and toxinological characterization of Greenland Protoceratium reticulatum and, in addition, to test the effect of temperature on growth and production of bioactive secondary metabolites. Seven clonal isolates, the first isolates of P. reticulatum available from arctic waters, were phylogenetically characterized by analysis of the LSU rDNA. Six isolates were further characterized morphologically and were shown to produce both yessotoxins (YTX) and lytic compounds, representing the first report of allelochemical activity in P. reticulatum. As shown for one of the isolates, growth was strongly affected by temperature with a maximum growth rate at 15°C, a significant but slow growth at 1°C, and cell death at 25°C, suggesting an adaptation of P. reticulatum to temperate waters. Temperature had no major effect on total YTX cell quota or lytic activity but both were affected by the growth phase with a significant increase at stationary phase. A comparison of six isolates at a fixed temperature of 10°C showed high intraspecific variability for all three physiological parameters tested. Growth rate varied from 0.06 to 0.19d, and total YTX concentration ranged from 0.3 to 15.0pg YTXcell and from 0.5 to 31.0pgYTXcell at exponential and stationary phase, respectively. All six isolates performed lytic activity; however, for two isolates lytic activity was only detectable at higher cell densities in stationary phase.
赤潮主要由海洋甲藻引起，已知会产生强效毒素，可能影响生态系统、人类活动和健康。在过去几十年中，这种事件在全球范围内的频率和强度都有所增加。全球变化涉及的许多过程在北极地区被放大，但对北极甲藻的特定物种反应知之甚少。这项工作的目的是对格陵兰原甲藻进行详尽的形态、系统发育和毒素学特征描述，并测试温度对生物活性次生代谢物生长和产生的影响。七个克隆分离株，是来自北极水域的第一批原甲藻分离株，通过 LSU rDNA 分析进行了系统发育特征描述。六个分离株进一步进行了形态特征描述，并显示出产生 both yessotoxins (YTX) 和裂解化合物的能力，这代表了原甲藻中首次报道的化感活性。正如对其中一个分离株的研究表明，生长受到温度的强烈影响，在 15°C 时最大生长速率，在 1°C 时显著但缓慢生长，在 25°C 时细胞死亡，表明原甲藻适应了温带水域。温度对总 YTX 细胞配额或裂解活性没有重大影响，但两者都受到生长阶段的影响，在静止阶段显著增加。在固定温度 10°C 下对六个分离株的比较表明，所有三个生理参数的种内变异性都很高。生长速率从 0.06 到 0.19d 不等，总 YTX 浓度范围从 0.3 到 15.0pg YTXcell 和从 0.5 到 31.0pgYTXcell，分别在指数和静止阶段。六个分离株均具有裂解活性；然而，对于两个分离株，只有在静止阶段较高的细胞密度下才能检测到裂解活性。
