Occurrence of Pseudo-nitzschia species and associated domoic acid production along the Guangdong coast, South China Sea
Occurrence of Pseudo-nitzschia species and associated domoic acid production along the Guangdong coast, South China Sea
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DOI：
10.1016/j.hal.2020.101899
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发表时间：
2020-09-01
期刊：
影响因子：
6.6
通讯作者：
Li, Yang
中科院分区：
文献类型：
--
作者：
Dong, Huan Chang;Lundholm, Nina;Li, Yang
在全球范围内，与失忆性贝类中毒事件有关的假尼奇硅藻属也是南海北岸广东沿海海域的主要有害微藻群之一。为探究其多样性和产毒特性，建立了伪尼茨氏菌分离株。基于形态学和分子特征，共鉴定出26个不同的伪nitzschia分类群，包括2个新种：P. uniseriata H.C. Dong & Yang Li和P. yuensis H.C. Dong & Yang Li。在形态学上，单叶杨的独特之处在于其条纹主要由一排孔组成，孔是简单的，内部没有分裂的膜，每个孔含有一个，很少有两个部门。羽拟刺槐的特征是具有包含一至两行孔体的条纹。在双柱条纹中，孔体呈多边形，分布不规则，中间可出现不连续的一排孔体。在单列条纹中，孔状体通常包含1-5扇区。根据ITS2序列结构信息进行系统发育分析，这两个类群与其他伪尼茨亚属有很好的区别。拟uniseriata p . lineola妹妹,而p yuensis形成一个组一起p . micropora和p . delicatissima。在比较ITS2二级结构时，发现单叶茅和lineola之间存在两种半代偿性碱基变化（HCBCs）。在云南云杉树和细叶云杉树之间存在1个代偿性碱基变化（CBC）和4个HCBCs，在云南云杉树和微孔云杉树之间存在1个代偿性碱基变化（CBC）和5个HCBCs。培养菌株产生颗粒DA （pDA）的能力显示，29株菌株属于7个物种：P. bipertita、P. caciantha、P. cuspidata、P. fraudulenta、P. fukuyoi、P. lundholmiae和P. multiseries。这是第一次报道双头藻有毒，其pDA含量为15.6 +/- 2.1 fg细胞（-1）。盐水对虾的存在使东北对虾、福山对虾、龙口对虾和多系对虾的pDA含量显著提高1.4 ~ 7倍，并使假对虾的pDA产量从低于检测限提高到17.5 +/- 1.6 fg细胞（-1）。在多系假蝇中检测到最高的pDA浓度为4830.5 +/- 120.3 fg cell(-1)，远低于北美和欧洲的报道。总体而言，广东沿海地区假尼茨氏菌的细胞毒素水平较低。
The diatom genus Pseudo-nitzschia, which has been associated with amnesic shellfish poisoning events globally, is also one of the key harmful microalga groups in Guangdong coastal waters, off the north coast of the South China Sea. In order to explore the diversity and toxigenic characteristics, Pseudo-nitzschia isolates were established. Based on a combination of morphological and molecular features, in total 26 different Pseudo-nitzschia taxa were identified, including two new species, P. uniseriata H.C. Dong & Yang Li and P. yuensis H.C. Dong & Yang Li. Morphologically, P. uniseriata is unique by having striae mainly comprising one row of poroids, which are simple without divided hymen internally, and each poroid containing one, seldom two sectors. Pseudonitzschia yuensis is characterized by having striae comprising one to two rows of poroids. In biseriate striae, the poroids are polygonal and irregularly distributed, and a discontinuous row of poroids may be present in the middle. In uniseriate striae, the poroids usually contain 1-5 sectors. Both taxa are well differentiated from other Pseudo-nitzschia species in phylogenetic analyses inferred from ITS2 sequence-structure information. Pseudonitzschia uniseriata is sister to P. lineola, whereas P. yuensis forms a group together with P. micropora and P. delicatissima. When comparing ITS2 secondary structure, two hemi-compensatory base change (HCBCs) are found between P. uniseriata and P. lineola. One compensatory base change (CBC) and four HCBCs are found between P. yuensis and P. delicatissima, and there is one CBC and five HCBCs between P. yuensis and P. micropora. The ability of cultured strains to produce particulate DA (pDA) revealed production of pDA in twenty-nine strains belonging to seven species: P. bipertita, P. caciantha, P. cuspidata, P. fraudulenta, P. fukuyoi, P. lundholmiae and P. multiseries. This is the first report of P. bipertita being toxic, with pDA content of 15.6 +/- 2.1 fg cell(-1). The presence of brine shrimps significantly increased pDA content in P. cuspidata, P. fukuyoi, P. lundholmiae and P. multiseries 1.4 to 7 times, and induced pDA production in P. fraudulenta from below detection limit to 17.5 +/- 1.6 fg cell(-1). The highest pDA concentration, 4830.5 +/- 120.3 fg cell(-1), was detected in P. multiseries, a level much lower than previous reports on P. multiseries from North America and Europe. Overall, the cellular toxin levels in Pseudo-nitzschia spp. were low in Guangdong coastal isolates.