Sam, Sahh and Map gene expression during cell division and paralytic shellfish toxin production of Alexandrium catenella (Dinophyceae)
Sam, Sahh and Map gene expression during cell division and paralytic shellfish toxin production of Alexandrium catenella (Dinophyceae)
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DOI：
10.2216/07-25.1
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发表时间：
2007-11-01
期刊：
影响因子：
1.6
通讯作者：
Koutoulis, Anthony
中科院分区：
文献类型：
--
作者：
Harlow, Lucy D.;Negri, Andrew;Koutoulis, Anthony
在甲藻链状亚历山大藻细胞分裂过程中，可能参与麻痹性贝类毒素（PST）生物合成的基因的表达进行了定量。神经毒性PST分子的基本前体，如S-腺苷甲硫氨酸（SAM），已被假设，但没有编码PST生产的基因已被确定在甲藻。SAM编码酶SAM合成酶和其他两个候选PST基因S-腺苷高半胱氨酸水解酶（Sahh）和甲硫氨酸氨基肽酶（Map）先前已被确定在密切相关的PST生产甲藻亚历山大fundyense。在A.链状体。A.链状结构主要由C2（30- 37mol%）、GTX 5（12- 19mol%）和GTX 6（27- 33mol%）组成，并且在整个细胞周期中是恒定的。然而，细胞PST的净产生率在细胞周期中变化，在细胞周期的G（2）+M期最高（127 fmol cell（-1）h（-1））（56%的细胞处于G（2）+M期），随着细胞进入G（1）期（66%的细胞处于G（1）期），其产生率显著降低（-14 fmol cell（-1）h-1）。定量真实的时间PCR显示，Sam，Sahh和Map在辐射前的PST产生和细胞分裂周期的G（2）+M期上调（每种情况下加倍）。链状亚历山大藻在这段黑暗时期活跃地产生PST，这表明光子辐照不是PST产生的直接触发因素。细胞分裂和PST产生之间的相互作用似乎很复杂，本研究已经证明了PST产生与Sam，Sahh和Map表达之间的相关性，这值得进一步研究。
The expression of genes potentially involved in paralytic shellfish toxin (PST) biosynthesis was quantified during cell division of the dinoflagellate Alexandrium catenella. Basic precursors of the neurotoxic PST molecule(s), such as S-adenosylmethionine (SAM), have been hypothesised, but no genes coding for PST production have been definitively identified in dinoflagellates. Sam encodes the enzyme SAM synthetase and two other candidate PST genes S-adenosylhomocysteine hydrolase (Sahh) and methionine aminopeptidase (Map) have been previously identified in the closely related PST producing dinoflagellate Alexandrium fundyense. PST production and expression of Sam, Sahh and Map were examined concurrently during cell division in A. catenella. The PST protile of A. catenella was dominated by C2 (30-37 mol%), GTX5 (12-19 mol%) and GTX6 (27-33 mol%) and was constant over the cell cycle. However, the net cellular PST production rate varied over the cell cycle and was highest (127 fmol cell(-1) h(-1)) during the G(2)+M phase of the cell cycle (56% cells in G(2)+M), slowing considerably (- 14 fmol cell(-1) h-1) as cells entered the G(1) phase (66% cells in G(1)). Quantitative real time PCR revealed that Sam, Sahh and Map were up-regulated (doubling in each case) during PST production and the G(2)+M phase of the cell division cycle before irradiance. Alexandrium catenella actively produced PSTs during this dark period, suggesting that photon irradiance was riot a direct trigger for PST production. Interactions between cell division and PST production appear complex and the present study has demonstrated correlations between PST production and expression of Sam, Sahh and Map, which warrants further investigation.