Thiazolylidene-ketonitriles are efficient inhibitors of photosynthetic electron flow in reaction centers from either Rhodobacter sphaeroides or Rhodobacter capsulatus. Some compounds of this class exhibit a higher inhibitor potency in the bacterial system as compared to photosystem II. Up to now, photosystem II inhibitors were generally less active in photosynthetic bacteria. An azido-thiazolyl...

Oxygenic photosynthesis is the principal producer of both oxygen and organic matter on earth. The primary step in this process--the conversion of sunlight into chemical energy--is driven by four multi-subunit membrane protein complexes named photosystem I, photosystem II, cytochrome b(6)f complex and F-ATPase. Photosystem I generates the most negative redox potential in nature and thus largely ...

Even though light is the ultimate substrate for photosynthetic energy conversion, it can also harm plants. This toxicity is targeted to the water-splitting photosystem II and leads to damage and degradation of the reaction centre D1-polypeptide. The degradation of this very important protein appears to be a direct consequence of photosystem II chemistry involving highly oxidizing radicals and t...

Temperature-induced changes in electron transport activities of chloroplasts isolated from chilling-sensitive and chilling-resistant plants have been examined. Using methylviologen as electron acceptor, temperature-induced changes occurred in the photosystem II plus photosystem I activities of chloroplasts isolated from chilling-resistant spinach (Spinacia oleracea L.) and pea (Pisum sativum L....

The midpoint potential of B F O . the sensitivity of its photoreduction to D C M U . D BM IB and K CN . and the photosystem I activity, suggest that the photoreduction of BFO in the chloroplast is at the primary electron acceptor x of photosystem I, and is irreversible. Rates of electron transport are similar in basal phosphorylating or uncoupled conditions al­ though electron transport is coup...

Although root-to-shoot communication has been intensively investigated in plants under drought, few studies have examined root-to-shoot communication under chilling. Here we explored whether root-to-shoot communication contributes to the chilling-light tolerance of cucumber shoots and clarified the key signal involves in this communication. After leaf discs chilling-light treatment, the photoin...

Photosystem II is a specialized protein complex that uses light energy to oxidize water, resulting in the release of molecular oxygen into the atmosphere, and to reduce plastoquinone, which is released into the hydrophobic core of the photosynthetic membrane. All oxygenic photosynthetic organisms, which include plants, algae and some bacteria, depend on photosystem II to extract electrons from ...