The earliest biological clock, or 2.5 billion years ago

Oxygen 2.5 billion years ago primitive life may have begun running the GSS first biological clock. A controversial paper published in the "natural" on the issue of the journal Nature on May 15 pointed out that the absorption of toxic byproducts of oxygen respiration - such as hydrogen peroxide - enzyme able to appear in the form of a cycle of gains and losses, exist in various forms of life.Almost all of the biological biochemical mechanism known as the circadian clock to maintain the GSTA1 intrinsic time. University of Cambridge, who led the latest research biochemist Akhilesh Reddy, said that in the absence of an external signal, for example the case of the sun, these loops around for a period of 24 hours, but they are also able to respond to external signals to be reset. For example, a passenger from the time difference in recovery, you must re-set your own biological clock.The body GSTA3 clocks are deeply entangled in the daily life of an organism. They help the plant leaves to find the timing of the capture of sunlight, and navigation for monarch butterflies in North America. The lack of circadian clock of the unicellular algae can not survive.Reddy pointed out that despite the biological clock is crucial and widespread, but is different in different in vivo control of clock genes. For example, will be a GSTK1 far cry from the circadian clock genes of Arabidopsis (Arabidopsis thaliana) and Drosophila and mammalian genes, suggesting that the biological clock is not evolved from a common ancestor. Reddy said: "We seem to think this cycle was repeated 'invented' five times."

The process of looking for a "universal" biological clock, Reddy and colleagues sights on a GSTM1 class of enzymes called antioxidant protein, they exist in almost all forms of life. This enzyme cycle between between the two chemical states, depending on whether it reacts with hydrogen peroxide, which is a byproduct of harmful oxygen cell respiration. 2011, Reddy, the Study Group report said about 24 hours, the cycle of peroxide reductase in human red blood cells between the two chemical states and seaweed.Today, Reddy, the research team of their observations extended to the mice, fruit flies and plants, and bacteria and archaea bacteria archaea more than 30 million years ago evolved cell life forms. Under the premise of the lack of sunlight, peroxide reductase able to keep time in all these organisms, which is a key feature of the circadian clock.The researchers found that the peroxide reductase, known as the metabolic biological clock does not depend on other biological clock. Reddy pointed out many internal mechanisms of the metabolism of the biological clock has not yet figure out.Reddy believes peroxide reductase is a good candidate for all biological clock ancestors. He and his colleagues assume that, as a response on photosynthesis in bacteria, this system about 2.5 billion years ago. This led to the gradual accumulation of oxygen in Earth's atmosphere, namely the so-called "great oxidation event.

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