Chloroplast DNA content in Dinophysis (Dinophyceae) from different cell cycle stages is consistent with kleptoplasty.
Chloroplast DNA content in Dinophysis (Dinophyceae) from different cell cycle stages is consistent with kleptoplasty.
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甲藻纲（Dinophyceae）不同细胞周期阶段的叶绿体 DNA 含量与盗窃形成一致。
DOI：
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发表时间：
2008
影响因子：
5.1
通讯作者：
S. Janson
中科院分区：
文献类型：
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作者：
Susanna Minnhagen;W. F. Carvalho;P. Salomon;S. Janson
盗窃成形术是保留从摄入的藻类猎物中获得的质体，这些质体可以暂时保持功能并可供捕食者用于光合作用。通过一种基于细胞周期分析的新方法，我们解决了有毒的、开花形成的甲藻 Dinophysnorvegica 是否进行盗贼成形术或者它们是否复制自己的质体 DNA 的问题。根据 DNA 含量，使用流式细胞仪将来自自然群体的分裂 (G2) 和非分裂 (G1) 褐藻细胞进行物理分离。 G1 和 G2 组中核和质体 rDNA 拷贝的平均数量均通过实时 PCR 进行定量。 G1组的细胞含有5800+/-340个核rDNA拷贝和1300+/-200个质体rDNA拷贝； G2 组的细胞含有 9700 +/- 58 拷贝的核 rDNA 和 1400 +/- 220 拷贝的质体 rDNA（平均值 +/- SD，n = 3）。每个细胞的平均 rDNA 拷贝数中 G2/G1 的比率对于核 DNA 为 1.67，对于质体 DNA 为 1.07。这些比率表明，褐藻中的质体获取要么与细胞周期脱钩，要么质体在细胞周期开始时由于摄食而迅速积累，正如在具有盗塑行为的原生生物中所预期的那样，但在具有自身质体复制的原生生物中则不然。此外，对用于实时 PCR 的同一群体的细胞进行流式细胞术测量表明，当没有质体猎物时，活的 Dinophys 细胞在 24 小时内平均损失了 36% 的质体藻红蛋白荧光。这些发现强烈表明褐藻不具备质体复制的能力。
Kleptoplasty is the retention of plastids obtained from ingested algal prey, which can remain temporarily functional and be used for photosynthesis by the predator. With a new approach based on cell cycle analysis, we have addressed the question of whether the toxic, bloom-forming dinoflagellate Dinophysis norvegica practice kleptoplasty or if they replicate their own plastid DNA. Dividing (G2) and non-dividing (G1) D. norvegica cells from a natural population were physically separated with a flow cytometer based on their DNA content. Average numbers of nuclear and plastid rDNA copies were quantified with real-time PCR both in the G1 and G2 group. Cells from the G1 group contained 5800 +/- 340 copies of nuclear rDNA and 1300 +/- 200 copies of plastid rDNA; cells from the G2 group contained 9700 +/- 58 copies of nuclear rDNA and 1400 +/- 220 copies of plastid rDNA (mean +/- SD, n = 3). The ratio G2/G1 in average rDNA copies per cell was 1.67 for nuclear DNA and 1.07 for plastid DNA. These ratios show that plastid acquisition in D. norvegica is either uncoupled with the cell cycle, or plastids accumulate rapidly in the beginning of the cell cycle owing to feeding, as would be expected in a protist with kleptoplastic behaviour but not in a protist with own plastid replication. In addition, flow cytometry measurements on cells from the same population used for real-time PCR showed that when kept without plastidic prey, live Dinophysis cells lost on average 36% of their plastid phycoerythrin fluorescence in 24 h. Together these findings strongly suggest that D. norvegica does not possess the ability for plastid replication.