Scalco Eleonora, Amato Alberto, Ferrante Maria Immacolata, Montresor Marina
Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
Protoplasma. 2016 Nov;253(6):1421-1431. doi: 10.1007/s00709-015-0891-5. Epub 2015 Oct 22.
Pseudo-nitzschia is a thoroughly studied pennate diatom genus for ecological and biological reasons. Many species in this genus, including Pseudo-nitzschia multistriata, can produce domoic acid, a toxin responsible for amnesic shellfish poisoning. Physiological, phylogenetic and biological features of P. multistriata were studied extensively in the past. Life cycle stages, including the sexual phase, fundamental in diatoms to restore the maximum cell size and avoid miniaturization to death, have been well described for this species. P. multistriata is heterothallic; sexual reproduction is induced when strains of opposite mating type are mixed, and proceeds with cells producing two functionally anisogamous gametes each; however, detailed cytological information for this process is missing. By means of confocal laser scanning microscopy and nuclear staining, we followed the nuclear fate during meiosis, and using time-lapse cinematography, we timed every step of the sexual reproduction process from mate pairing to initial cell hatching. The present paper depicts cytological aspects during gametogenesis in P. multistriata, shedding light on the chloroplast behaviour during sexual reproduction, finely describing the timing of the sexual phases and providing reference data for further studies on the molecular control of this fundamental process.
由于生态和生物学原因，拟菱形藻属是一个经过充分研究的羽纹硅藻属。该属中的许多物种，包括多列拟菱形藻，都能产生软骨藻酸，一种导致失忆性贝类中毒的毒素。过去对多列拟菱形藻的生理、系统发育和生物学特征进行了广泛研究。该物种的生命周期阶段，包括有性阶段（这在硅藻恢复最大细胞大小并避免因细胞缩小而死亡的过程中至关重要），已有详细描述。多列拟菱形藻是异宗配合的；当相反交配型的菌株混合时会诱导有性繁殖，每个细胞会产生两个功能上异形的配子；然而，这个过程的详细细胞学信息尚缺。通过共聚焦激光扫描显微镜和细胞核染色，我们追踪了减数分裂过程中细胞核的命运，并使用延时摄影技术，记录了从配偶配对到初始细胞孵化的有性繁殖过程的每一步。本文描述了多列拟菱形藻配子发生过程中的细胞学方面，揭示了有性繁殖过程中叶绿体的行为，精确描述了有性阶段的时间，并为进一步研究这一基本过程的分子控制提供了参考数据。
