Department of Chemistry, Canterbury University, Private Bag 4800, Christchurch 8140, New Zealand.
Toxicon. 2011 Mar 15;57(4):566-73. doi: 10.1016/j.toxicon.2010.12.020. Epub 2011 Jan 9.
Saxitoxins or paralytic shellfish poisons (PSP) are neurotoxins produced by some species of freshwater cyanobacteria and marine dinoflagellates. Samples collected from the metaphyton of a drinking-water supply's pre-treatment reservoir and a small eutrophic lake in New Zealand returned positive results when screened using a Jellett PSP Rapid Test Kit. The dominant species in the sample was identified as Scytonema cf. crispum. A non-axenic clonal culture (UCFS10) was isolated from the lake. The partial 16S rRNA gene sequence shared only a 91% or less sequence similarity with other Scytonema species, indicating that it is unlikely that this genus is monophyletic and that further in-depth phylogenetic re-evaluation is required. The sxtA gene, which is known to be involved in saxitoxin production, was detected in UCFS10. Saxitoxin concentrations were determined from the lake samples and from UCFS10 using pre-column oxidation high performance liquid chromatography with fluorescence detection. Saxitoxin was the only variant detected and this was found at concentrations of 65.6 μg g⁻¹ dry weight in the lake sample and 119.4 μg g⁻¹ dry weight or 1.3 pg cell⁻¹ in UCFS10. This is the first confirmation of a saxitoxin-producing species in New Zealand and the first report of saxitoxin production by a species of Scytonema.
贝类毒素或麻痹性贝类毒素（PSP）是由一些淡水蓝藻和海洋甲藻产生的神经毒素。使用 Jellett PSP 快速检测试剂盒对取自新西兰饮用水供应预处理水库和一个小型富营养化湖泊的底栖生物样品进行筛选，结果呈阳性。样品中的优势物种被鉴定为 Scytonema cf. crispum。从湖中分离出非纯培养的克隆培养物（UCFS10）。部分 16S rRNA 基因序列与其他 Scytonema 物种的相似性仅为 91%或更低，表明该属不太可能是单系的，需要进一步深入的系统发育重新评估。检测到已知参与贝类毒素产生的 sxtA 基因在 UCFS10 中。使用柱前氧化高效液相色谱法和荧光检测法从湖泊样品和 UCFS10 中测定贝类毒素浓度。仅检测到贝类毒素这一种变体，在湖泊样品中的浓度为 65.6 μg g⁻¹ 干重，在 UCFS10 中的浓度为 119.4 μg g⁻¹ 干重或 1.3 pg 细胞⁻¹。这是新西兰首次确认产贝类毒素的物种，也是首次报道 Scytonema 物种产生贝类毒素。
