Acceleration of the rate of nitrite oxidation by freezing in aqueous solution

Article Abstract:

The oxidation reaction in which dissolved oxygen converts nitrate to nitrate can be speeded up greatly by occurring in a solution being frozen. The rate of oxidation goes up by 10 to the fifth power at a pH of 4.5, a temperature of 25 degrees C and a freezing rate of 0.2 g solution per minute. Moreover, the reaction rate goes up as the freezing rate rises. The speeding-up is not brought about by thermochemical, photochemical, simple electrochemical or catalytic influences although the true cause has yet to be determined. This sort of accelerated oxidation may be occurring in the atmosphere.

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Three-dimensional structure of photosystem II

Article Abstract:

Digital image processing has revealed a three-dimensional, functional structure of photosystem II (PSII) with antennae and core light-harvesting proteins in higher plants. The PSII, located in the thylakoid membranes of plants and cyanobacteria, is the place for photosynthetic oxidation of water. The core of the PSII contains light-harvesting proteins and a reaction center.

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Detection of an intermediate of photosynthetic water oxidation

Article Abstract:

Experimental evidence is provided for an intermediate of the enigmatic reaction pathway from water to oxygen. It shows the backpressure of oxygen on Mn4Ca center, and re-investigates the oxygen consumption of PSII under conditions of varied oxygen pressure.

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