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MODERN SYSTEM INEFFICIENCY. "These protective mechanisms involve fine-tuning of reduction potentials, switching of pathways and the use of short circuits, back-reactions and side-paths, all of which compromise efficiency." https://lnkd.in/dxpcWx8 View in LinkedIn

THE GREAT OXYGENATION EVENT. "It is widely assumed that atmospheric oxygen concentrations remained persistently low (less than 10−5 times present levels) for about the first 2 billion years of Earth’s history. The first long-term oxygenation of the atmosphere is thought to have taken place around 2.3 billion years ago, during the Great Oxidation Event." https://lnkd.in/euqjmtw View in LinkedIn

FINGER IN THE DYKE. "The tuning of electron transfer needed to deal with leaks and damaging back-reactions seems to be a requirement associated with life in the presence of oxygen." https://lnkd.in/dxpcWx8 View in LinkedIn

FRAGMENT FROM NATURE deals with some examples of how changes in the environment could have made many molecular mechanisms redundant without considerable molecular exaptation and serious work-around and bolt-ons, just as had happened with physical structures like feet. Here we see photosynthetic futile cycles and carefully positioned carotenoids operating as adaptations to the challenges of an oxygenated atmosphere. View in LinkedIn

BOLT-ON SOLUTIONS. "These features evolved in ancestral enzymes in a low O2 environment. When O2 appeared, energy-converting enzymes had to deal with its troublesome chemistry. Various protective mechanisms duly evolved that are not directly related to the enzymes’ principal redox roles." https://lnkd.in/dxpcWx8 View in LinkedIn

Johnson & Johnson to pay $4.7bn damages in talc cancer case. The family company. http://www.bbc.co.uk/news/business-44816805 View in LinkedIn

DELICATE BALANCE. "The energy wasteful reactions are a particular problem for photosynthetic reaction centres because the photochemistry gives such high energy intermediates. This problem is mainly dealt with through kinetic control: i.e. the forward reactions are faster than the back reactions. This is achieved by having cofactors appropriately spaced within the protein to allow rapid vectorial electron transfer across the membrane, separating the positive and negative charges from each other." https://lnkd.in/dxpcWx8 View in LinkedIn

"EMBRYONIC and neonatal mice can regenerate their digit tips if they are amputated through the distal phalanx, and similar digit tip regeneration occurs in humans." http://onlinelibrary.wiley.com/doi/10.1111/j.1440-169X.2007.00973.x/full View in LinkedIn

ANCIENT WORK-AROUNDS. "The energy-converting redox enzymes perform productive reactions efficiently despite the involvement of high energy intermediates in their catalytic cycles. This is achieved by kinetic control: with forward reactions being faster than competing, energy-wasteful reactions. This requires appropriate cofactor spacing, driving forces and reorganizational energies." https://lnkd.in/dxpcWx8 View in LinkedIn

PREVIOUSLY EFFICIENT. "The energy-converting enzymes evolved from ancestral enzymes that functioned in conditions of low O2 concentration or anaerobicity. These ancestral proteins did not have to deal with the inevitable side-reactions (leaks) that occur when O2 is present." https://lnkd.in/dxpcWx8 View in LinkedIn