Search results for "Plastoquinone"
showing 7 items of 7 documents
The Water to Water Cycles in Microalgae.
2016
In oxygenic photosynthesis, light produces ATP plus NADPH via linear electron transfer, i.e. the in-series activity of the two photosystems: PSI and PSII. This process, however, is thought not to be sufficient to provide enough ATP per NADPH for carbon assimilation in the Calvin-Benson-Bassham cycle. Thus, it is assumed that additional ATP can be generated by alternative electron pathways. These circuits produce an electrochemical proton gradient without NADPH synthesis, and, although they often represent a small proportion of the linear electron flow, they could have a huge importance in optimizing CO2 assimilation. In Viridiplantae, there is a consensus that alternative electron flow comp…
Novel atrazine-binding biomimetics inspired to the D1 protein from the photosystem II of Chlamydomonas reinhardtii.
2020
Biomimetic design represents an emerging field for improving knowledge of natural molecules, as well as to project novel artificial tools with specific functions for biosensing. Effective strategies have been exploited to design artificial bioreceptors, taking inspiration from complex supramolecular assemblies. Among them, size-minimization strategy sounds promising to provide bioreceptors with tuned sensitivity, stability, and selectivity, through the ad hoc manipulation of chemical species at the molecular scale. Herein, a novel biomimetic peptide enabling herbicide binding was designed bioinspired to the D1 protein of the Photosystem II of the green alga Chlamydomonas reinhardtii. The D1…
Cyclic and noncyclic photophosphorylation during the ontogenesis of high-light and low-light leaves of Sinapis alba.
1981
Noncyclic electron transport to ferricyanide and photophosphorylation as well as the methylviologen mediated aerobic and anaerobic photophosphorylation with dichlorophenolindophenol-ascorbate as the electron donor of photosystem I were measured during the development of high-light and low-light adapted leaves of Sinapis alba. Anaerobic methylviologen-catalyzed phosphorylation is more than twice as high as aerobic phosphorylation. The difference between the rates of aerobic and anaerobic phosphorylation is sensitive to dibromothymoquinone. Thus, under anaerobic conditions, methylviologen mediates a cyclic phosphorylation including plastoquinone. All photochemical activities of high-light chl…
Fluorescence induction kinetics as a tool to detect a chlororespiratory activity in the prasinophycean alga, Mantoniella squamata
1990
Abstract Pulse-modulated fluorescence measuring systems were used to study the fluorescence induction kinetics of the primitive prasinophycean alga, Mantoniella squamata . DCMU-treated cells show a very strong non-photochemical quenching which is insensitive to uncouplers and can not be attributed to state transitions or photoinhibition. In order to analyze the origin for this quenching, different inhibitors of the photosynthetic electron flow were applied. It was found that DCCD, an inhibitor of the ATP-synthase as well as of the cytochrome- c oxidase, enhances the fluorescence quenching, whereas antimycin A, which blocks the cyclic electron flow around PS I, stimulates it. The effect of b…
Quantum dots functionalised artificial peptides bioinspired to the D1 protein from the Photosystem II of Chlamydomonas reinhardtii for endocrine disr…
2021
Herein we describe the design and synthesis of novel artificial peptides mimicking the plastoquinone binding niche of the D1 protein from the green photosynthetic alga Chlamydomonas reinhardtii, also able to bind herbicides. In particular, molecular dynamics (MD) simulations were performed to model in silico the behaviour of three peptides, D1Pep70-H, D1Pep70-S264K and D1Pep70-S268C, as genetic variants with different affinity towards the photosynthetic herbicide atrazine. Then the photosynthetic peptides were functionalised with quantum dots for the development of a hybrid optosensor for the detection of atrazine, one of the most employed herbicides for weed control in agriculture as well …
Light Regulation of the Thylakoid LHCII Protein Phosphorylation at the Substrate Level
1998
The distribution of light energy between the two photosystems as well as the light-induced turnover of PSII proteins are regulated by the reversible phosphorylation of LHCII and the PSII-core proteins. The thylakoid protein kinase(s) is activated by a signal transduction system involving the interaction of reduced plastoquinone with the quinol oxidation site of the cytochrome bf complex [1]. Phosphorylation of the mobile pool of LHCII induces dissociation of this antenna from PSII and allows its interaction with the PSI in the stroma exposed membranes (state transition)[21. Dephosphorylation of LHCII by a membrane -bound phosphatase appears to be regulated by a cyclophilinlike protein locat…
Correlative Analysis of the Photosynthetic Capacity and Different Components of the Photosynthetic Apparatus
1984
The majority of higher plants is able to adapt to the ecological factor light in a wide range. Depending on the light intensity and the light quality during growth, plant with an equal genotype develop into so-called low light and high light forms. The photosynthetic adaptation to different light conditions involves complex, balanced changes of many leaf features. The changes of physiological factors of photosynthesis includes differences in the CO2 conductance, in the Calvin cycle enzymes, the capacity of electron transport, the photophosphorylation and the pigments (Boardman, 1977; Wild, 1979; Bjorkman, 1981; Lichtenthaler et al., 1981). The adaptation of individual plants or leaves to lo…