Original title: The role of metals in photosynthesis regulation of Trichodesmium
Authors: COLUSSI, Antonio
Document type: Doctoral theses
Year: 2025
Language: eng
Abstract: The surfaces of the oceans tend to be poor in free nutrients. Trichodesmium is a cyanobacterium living in these oligotrophic environments and it is a key genus for the nutrient fluxes and for all the food chain. This study focussed on two aspects of iron-limitation: an alternative nutrient source Trichodesmium is able to use, and the effect of this limitation on the photosynthesis of this cyanobacterium. Regarding the photosynthesis, previous studies have found that the PhotoSystem II of this organism is needed as power source for the energy-demanding protein nitrogenase, core protein of the nitrogen fixation. These two complexes seem to belong to two mutually-excluding processes (oxygen-producing photosynthesis and oxygen-sensitive nitrogen fixation), but Trichodesmium has evolved to perform both at the same time. This study was done with a particular focus on how the electron flux around PSII is regulated in response to long-term controlled iron-limiting conditions. Despite the measurable stress the cells were undergoing, electrons were still able to flow between photosystems. In parallel, in the context of the collaboration of our laboratory with the Laboratory of Prof. Shaked of the Interuniversity Institute of Marine Sciences in Eilat (Israel), the intracolony and intracellular distribution of different elements (in particular iron) was studied in relation to different nutrient sources. It was hypothesized that one important source of iron for Trichodesmium was represented by solid matter and not only by what is available in solution. This was confirmed by our work, which proved for the first time that the contact between filaments and particles was needed for the uptake of iron from dust, and measured its effect on a high number of colonies. Developing our knowledge in these two fields will improve our understanding on the primary production in the oceans and could help in making more accurate forecasts for the future.
Keywords: chromoatography; colony; dust; ICP-MS; IMS101; iron; metalloproteins; metalloproteomics; nitrogenase; photosynthesis; PSII; Red Sea; Trichodesmium; XRF
Citation: COLUSSI, Antonio. The role of metals in photosynthesis regulation of Trichodesmium. České Budějovice, 2025. disertační práce (Ph.D.). JIHOČESKÁ UNIVERZITA V ČESKÝCH BUDĚJOVICÍCH. Přírodovědecká fakulta

Institution: University of South Bohemia in České Budějovice (web)
Document availability information: Fulltext is available in the Digital Repository of University of South Bohemia.
Original record: http://www.jcu.cz/vskp/77674

Permalink: http://www.nusl.cz/ntk/nusl-684945


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Universities and colleges > Public universities > University of South Bohemia in České Budějovice
Academic theses (ETDs) > Doctoral theses