The sexual phase of the diatom Pseudo-nitzschia multistriata: cytological and time-lapse cinematography characterization
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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.
KeywordsChloroplasts Diatoms Life cycle Pseudo-nitzschia multistriata Sexual reproduction Time-lapse cinematography
The authors would like to thank Dr. Giovanna Benvenuto (Unit Morpho-Functional Analyses and Bioimaging, Stazione Zoologica Anton Dohrn) for her assistance with CLSM and time-lapse microscopy. E.S. has been supported by a PhD fellowship from Stazione Zoologica Anton Dohrn. A.A. was funded by the EC FP7-People COFUND (GA n. 600407) and RITMARE (Ricerca ITaliana per il MARE) Flagship Project. This work was partially supported by the Marie Curie FP7-PEOPLE-2011-CIG 293887 (GyPSy) grant to M.I.F.
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Conflict of interest
The authors declare that they have no competing interests.
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