Sabatino, Valeria (2017) Silencing of lipoxygenase pathways in the diatom genus Pseudo-nitzschia. [Tesi di dottorato]


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Tipologia del documento: Tesi di dottorato
Lingua: English
Titolo: Silencing of lipoxygenase pathways in the diatom genus Pseudo-nitzschia
Data: 10 Aprile 2017
Numero di pagine: 108
Istituzione: Università degli Studi di Napoli Federico II
Dipartimento: Biologia
Dottorato: Biologia
Ciclo di dottorato: 29
Coordinatore del Corso di dottorato:
Fontana, Angelo[non definito]
Ferrante, Maria Immacolata[non definito]
Data: 10 Aprile 2017
Numero di pagine: 108
Parole chiave: diatoms, lipoxygenase, gene-silencing
Settori scientifico-disciplinari del MIUR: Area 05 - Scienze biologiche > BIO/10 - Biochimica
Area 05 - Scienze biologiche > BIO/11 - Biologia molecolare
Area 05 - Scienze biologiche > BIO/13 - Biologia applicata
Informazioni aggiuntive: Il dottorato è stato svolto presso l'istituto di chimica biomolecolare ICB di Pozzuoli e presso la Stazione Zoologica Anton Dohrn di Napoli
Depositato il: 20 Apr 2017 11:36
Ultima modifica: 16 Mar 2018 12:00
DOI: 10.6093/UNINA/FEDOA/11616


Diatoms are unicellular eukaryotic organisms that are responsible for about 40% of the marine primary production. They also contribute to the biogeochemical cycles in the oceans. Diatoms produce oxylipins, a varied family of lipoxygenase-derived metabolites that share a structural motif arising from the addition of oxygen to polyunsaturated fatty acids (PUFAs). Oxylipins are widely distributed in animals and plants, where they are involved in a broad spectrum of actions including stress and defense responses, regulation of growth and development, signaling, and innate immunity. In diatoms, oxylipins have been proposed as ecological and physiological mediators but their function has not been proven in any species mostly because of the lack of molecular tools. The aim of this doctoral thesis was the functional study of lipoxygenase (LOX) pathways in the ecologically relevant Pseudo-nitzschia genus. Transformation of Pseudo-nitzschia arenysensis empowered the use of RNAi to silence for the first time LOX genes in this species. Experimental evidence showed that the two LOX pathways previously described in P. arenysensis were affected by this process with resulting reduction of the levels of corresponding oxylipins. The silenced diatom cells revealed a reduced growth compared to wild type cells and showed a phenotype with a marked photoinhibition, thus confirming the regulatory role of LOX pathways in diatoms and suggesting a direct link between oxylipins and cell resilience. Overall, this study shows the first correlation between a diatom gene and the synthesis of lipid mediators, providing direct evidence that the reduction of lipoxygenase expression levels are correlated to a marked physiological effect.

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