Fabro Elena, Almandoz Gastón O, Ferrario Martha, John Uwe, Tillmann Urban, Toebe Kerstin, Krock Bernd, Cembella Allan
División Ficología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Paseo del Bosque s/n (B1900FWA), La Plata, Argentina.
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
J Phycol. 2017 Dec;53(6):1206-1222. doi: 10.1111/jpy.12574. Epub 2017 Sep 14.
In the Argentine Sea, blooms of toxigenic dinoflagellates of the Alexandrium tamarense species complex have led to fish and bird mortalities and human deaths as a consequence of paralytic shellfish poisoning (PSP). Yet little is known about the occurrence of other toxigenic species of the genus Alexandrium, or of their toxin composition beyond coastal waters. The distribution of Alexandrium species and related toxins in the Argentine Sea was determined by sampling surface waters on an oceanographic expedition during austral spring from ~39°S to 48°S. Light microscope and SEM analysis for species identification and enumeration was supplemented by confirmatory PCR analysis from field samples. The most frequent Alexandrium taxon identified by microscopy corresponded to the classical description of A. tamarense. Only weak signals of Group I from the A. tamarense species complex were detected by PCR of bulk field samples, but phylogenetic reconstruction of rDNA sequences from single cells from one station assigned them to ribotype Group I (Alexandrium catenella). PCR probes for Alexandrium minutum and Alexandrium ostenfeldii yielded a positive signal, although A. minutum morphology did not completely match the classical description. Analysis of PSP toxin composition of plankton samples revealed toxin profiles dominated by gonyautoxins (GTX1/4). The main toxic cyclic imine detected was 13-desMe-spirolide C and this supported the association with A. ostenfeldii in the field. This study represents the first integrated molecular, morphological and toxinological analysis of field populations of the genus Alexandrium in the Argentine Sea.
在阿根廷海域，塔玛亚历山大藻（Alexandrium tamarense）物种复合体中的产毒甲藻大量繁殖，导致鱼类和鸟类死亡以及人类因麻痹性贝类中毒（PSP）而死亡。然而，对于亚历山大藻属其他产毒物种的发生情况，以及其在沿海水域以外的毒素组成，人们了解甚少。通过在南半球春季从约南纬39°至48°进行的一次海洋学考察中采集表层水样，确定了阿根廷海域亚历山大藻物种及其相关毒素的分布。通过现场样本的验证性PCR分析，补充了用于物种鉴定和计数的光学显微镜和扫描电子显微镜分析。显微镜鉴定出的最常见的亚历山大藻分类单元与塔玛亚历山大藻的经典描述相符。通过对大量现场样本进行PCR检测，仅检测到来自塔玛亚历山大藻物种复合体第一组的微弱信号，但对一个站点单细胞的rDNA序列进行系统发育重建后，将它们归为第一核糖体类型组（链状亚历山大藻，Alexandrium catenella）。尽管微小亚历山大藻（Alexandrium minutum）的形态与经典描述并不完全匹配，但针对微小亚历山大藻和奥氏亚历山大藻（Alexandrium ostenfeldii）的PCR探针产生了阳性信号。浮游生物样本的PSP毒素组成分析显示，毒素谱以膝沟藻毒素（GTX1/4）为主。检测到的主要有毒环状亚胺是13-去甲基螺旋环内酯C，这支持了其在现场与奥氏亚历山大藻的关联。这项研究是对阿根廷海域亚历山大藻属野外种群进行的首次综合分子、形态和毒素学分析。
