The photosynthesis and related plant productivity aspects of plants and cyanobacteria depend upon the functioning of photosystem 2 (PS2), associated with D1 and D2 heterodimer reaction centre core proteins. The D1 protein is encoded by psbA gene, genetically localized on the plastid genome (cpDNA), contains functional cofactors of PS2 in association with D2 protein, and also functions for radiant energy transformation through oxidation of water and reduction of plastoquinone. Surprisingly, D1 protein accounts for even less than 1% of the total thylakoid membrane protein content. In spite of that, its rate of turnover is very much comparable to ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) large subunit, most abundantly present in green tissue. The normal functioning of PS2 possesses damage-repair cycles of D1 protein. Generally, rate of photodamage does not exceed the rate of repair under optimal growth conditions, therefore, no adverse effect on photosynthetic efficiency is manifest. However, under strong irradiance coupled with elevated temperature, level of photodamage exceeds the rate of repair, resulting in photoinhibition, photodegradation of D1 protein, and lowering photosynthetic efficiency linked with plant productivity eventually. The features of D1 turnover process are reviewed, particularly with respect to molecular mechanisms.
Fabrication of plasmonic nanoantennas with resonance frequencies in visible range is often challenging due to the necessity of exposure of nonconductive substrates. This work is focused in comparison of conventional fabrication approach using conductive polymer layers and alternative variable pressure electron beam lithography (VP-EBL) method. We have also studied the stability of VP-EBL process for long exposures. and Výroba plazmonických nanoantén s rezonančními frekvencemi ve viditelné oblasti pomocí elektronové litografie mnohdy přináší nutnost expozice nevodivých substrátů. Tato práce je zaměřena na porovnání výsledků dosažitelných konvenčním přístupem za použití vodivých polymerů a alternativního postupu v podobě litografie za variabilního tlaku (VP-EBL). Dále je testována stabilita VP-EBL procesu pro dlouhodobé expozice.