Speaker: Dr Rowena Ball Affiliation: Australian National University
Date: Friday 7th October
Time: 10.30-11.30 am
Title: The life story of hydrogen peroxide
Abstract: The story of the relationship between hydrogen peroxide and life is complex and ongoing, and fraught with misapprehensions. Living cells make and break hydrogen peroxide, and, after a long period when it was reviled as a toxic cell vandal and saboteur of gene transcription fidelity, evidence is mounting that its relationship with living organisms is intimate and vital. This relationship is usually assumed to have begun with the evolution around 2.3 billion years ago of oxygen-evolving photosynthesis. Yet hydrogen peroxide was present on Earth before photosynthetic cells appeared, and primitive anaerobes must have come to some arrangement with it. And what of its role with respect to proto-cellular life, the putative RNA world?
In a series of four papers John Brindley and I developed and tested the hypothesis that hydrogen peroxide was essential to the development of the RNA world on Earth more than 3.8 billion years ago, and that it set the scene for the emergence of cellular life [1-4]. In this talk I shall synthesise and interpret those works, and ask a key relevant question: Are we all really vampires? First I review the thiosulfate-hydrogen peroxide (THP) redox oscillator and discuss its dynamic interactions with the proto-cellular RNA world, providing a periodic power source, initiating the universal dependence of all life on the proton motive force, and acting as a driver for change. We conjectured that the axial chirality of hydrogen peroxide may have played a key role in homochiral amplification of D-ribonucleic acids and extinction of the L species, and I shall discuss the possible mechanism for this action and present a simple process model.
All this leads us to consider the irony of it all: Biggest consumer of hydrogen peroxide today is the plastics industry. Hydrogen peroxide enabled life to establish on Earth, which in due course evolved a creature capable of manufacturing hydrogen peroxide and vast amounts of plastic. Then we dump the plastic waste in the ocean, which kills off life. Images in the media of plastic garbage in the oceans, and of dead marine creatures strangled by plastic waste, are surely a sad answer to the question, "what is life's purpose?"
- Ball R, Brindley J (2015) J. Roy. Soc. Interface 12, 20150366 (doi 10.1098/rsif.2015.0366).
- Ball R, Brindley J (2016) Origins of Life and Evolution of Biospheres 46, 81-93. (doi 10.1007/s11084-015-9465-y).
- Ball R, Brindley J (2016) Origins of Life and Evolution of Biospheres 46, 133-147. (doi 10.1007/s11084-015-9448-z).
- Ball R, Brindley J (2014) Journal of the Royal Society Interface 11, 20131052, 2014. (doi 10.1098/rsif.2013.1052).
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