College of Life Science and Technology, Jinan University, Guangzhou 510632, China; Third Institute of Oceanography, SOA, Xiamen 361005, China.
Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany.
Harmful Algae. 2016 May;55:56-65. doi: 10.1016/j.hal.2016.02.006. Epub 2016 Feb 25.
Azadinium poporum produces a variety of azaspiracids and consists of several ribotypes, but information on its biogeography is limited. A strain of A. poporum (GM29) was incubated from a Gulf of Mexico sediment sample. Strain GM29 was characterized by a plate pattern of po, cp, x, 4', 3a, 6″, 6C, 5S, 6‴, 2⁗, a distinct ventral pore at the junction of po and the first two apical plates, and a lack of an antapical spine, thus fitting the original description of A. poporum. The genus Azadinium has not been reported in waters of the United States of America before this study. Molecular phylogeny, based on large subunit ribosomal DNA (LSU rDNA) and internal transcribed spacer (ITS) sequences, reveals that strain GM29 is nested within the well-resolved A. poporum complex, but forms a sister clade either to ribotype B (ITS) or ribotype C (LSU). It is, therefore, designated as a new ribotype, termed as ribotype D. LSU and ITS sequences similarity among different ribotypes of A. poporum ranges from 95.4% to 98.2%, and from 97.1% to 99.2% respectively, suggesting that the LSU fragment is a better candidate for molecular discrimination. Azaspiracid profiles were analyzed using LC-MS/MS and demonstrate that strain GM29 produces predominantly AZA-2 with an amount of 45fg/cell. The results suggest that A. poporum has a wide distribution and highlights the risk potential of azaspiracid intoxication in the United States.
波氏菱形海胆产生多种azaspiracids，并由多个核糖体型组成，但有关其生物地理学的信息有限。从墨西哥湾沉积物样本中培养出一株波氏菱形海胆（GM29）。菌株 GM29 的特征是具有 po、cp、x、4'、3a、6″、6C、5S、6‴、2⁗ 的板模式，在 po 和前两个顶片的交界处有一个明显的腹孔，并且缺乏抗顶棘，因此符合波氏菱形海胆的原始描述。在本研究之前，美国水域尚未报道过 Azadinium 属。基于大亚基核糖体 DNA（LSU rDNA）和内部转录间隔区（ITS）序列的分子系统发育表明，菌株 GM29 嵌套在已明确界定的波氏菱形海胆复合体中，但与核糖体型 B（ITS）或核糖体型 C（LSU）形成姐妹分支。因此，它被指定为一个新的核糖体型，称为核糖体型 D。核糖体型 A. poporum 的 LSU 和 ITS 序列相似性在 95.4%到 98.2%之间，而在 97.1%到 99.2%之间，这表明 LSU 片段是分子鉴别更好的候选者。使用 LC-MS/MS 分析了 azaspiracid 图谱，结果表明菌株 GM29 主要产生 AZA-2，其含量为 45fg/细胞。结果表明，波氏菱形海胆分布广泛，并突出了美国azaspiracid 中毒的潜在风险。
