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by Staff Writers Boston MA (SPX) Aug 20, 2010
A revolutionary series of discoveries ushers in a new paradigm in our understanding of how life began. In this month's issue of the online Journal of Cosmology, Dr. Michael Russell and colleagues, of NASA, JPL, and the California Institute of Technology, have detailed a bold new theory, supported by considerable evidence, demonstrating how life emerged in the tempestuous water-world that was our planet four billion years ago. In the same edition of the Journal of Cosmology, Dr. Russell's work receives near unanimous support from 12 independent scientists who report on the evolutionary stages taken by life, right from its emergence in a warm and bitter submarine spring spewing hydrogen-rich waters into a carbonated ocean, through the process of metabolism, onto the RNA world, to the first viruses, and bacteria to animals, humans and consciousness. Many are saying this bold new theory is a watershed, revolutionary achievement, which promises to create a scientific revolution. According to one of the contributors, Professor John F. Allen of Queen Mary, University of London, "Mike Russell has created a new paradigm in the sense of Thomas Kuhn.a euros Behold the next scientific revolution: How life began. For thousands of years scientists have pondered life's origins, many creating fanciful scenarios with fully formed life emerging from the soil and even dead bodies. More recently, eminent scientists have concluded that even the simplest of cells is so complex, that it is almost beyond our imagination to conceive of how even proto-cells may have formed. Even the nature of pre-life, the first proto-organisms, has been a matter of bitter debate, with scientists advocating numerous possible scenarios and others pointing out their fatal flaws. In fact, there is no general agreement as to exactly what life is, thus making it nearly impossible to determine how life began. According to Russell, in order to understand this age old problem we shouldn't ask what life is, but what life does. What life does is take carbon dioxide from the atmosphere or the ocean and react it with hydrogen gleaned from water to produce waste products such as methane, acetate and, later in Earth's history, oxygen. Life can push a planet like ours closer to chemical and physical equilibrium, and here is the key clue to the emergence of life: disequilibrium. Out of chaos there came order, and it was alive. More specifically, carbon dioxide from volcanoes, and the hydrogen emanating from the Earth at hot springs or produced by photosynthesis, are out of equilibrium. They want to react but are inhibited from doing so by the symmetry of the carbon dioxide molecule. Life is the catalyst that encourages and quickens their interaction. If carbon dioxide were to have easily reacted with hydrogen there would have been no call for life chemistry would have done the job. But the early Earth had a very rich carbon dioxide atmosphere indeed, perhaps the equivalent of ten atmospheres. How to resolve the chemical tension and approach equilibrium? Life was the solution. Yet, where was life first fashioned? Some scientists have argued Early Earth did not contain the necessary ingredients, and even if present, they would have had to accumulate in the same location. Statistically, some believe the odds of life beginning on Earth border on impossibility. Location is a key to understanding the origins of life, and Dr. Russell discovered that location many years ago. Life began in the first ocean, at a thermal vent where the two fluids with the necessary chemicals reacted together to jump start life. As detailed by Russell and colleagues in this months Journal of Cosmology, the advantage of a submarine spring for life's hatchery is that all the requirements of life are delivered on site by convection currents the electrochemical energy (up to 1 volt, commensurate with what life is currently driven by), hydrogen, ammonia, phosphate and all those trace metals that make up the active centers of the metalloenzymes to this day. What was missing were organic molecules but making those was proto-life's first job. Life did not emerge as life, but evolved into life, and life's intermediary was cell-like proto-life which began as a series of compartments almost identical to those fashioned naturally in under sea thermal vents such as the romantically named Lost City, to this day. The steps from inorganic to organic to proto-life were rife with difficulties. Pathways were beaten from hydrogen plus carbon dioxide through formate and formaldehyde to a methyl group and thereby to acetate and pyruvate and to other carboxylic acids. Some of these organic acids were probably aminated with hydrothermal ammonia to amino acids in reactions encouraged by the alkaline conditions obtaining in the hydrothermal hatchery. Yet, to get started, the vehicle of life had not only to be inorganic but also cell-like to take advantage of the energy available from gradients building up across the cellular walls gradients of pH, redox and temperature as well as the hydrothermal delivery of that best of all fluid fuels, hydrogen. Compartments form naturally in undersea vents and these compartments were able to hold in the organic products from reactions between the carbon dioxide, the hydrogen, phosphate, ammonia and sulfide, catalyzed by the transition metals. The prototype compartmentalized vehicles of life were therefore hybrids, driven by electrochemical as well as chemical energy; the exhaust effluents were acetate and methane. Only once the vehicle's engine had been fabricated could the system be regulated and the plans laid for reproduction. In other words metabolism had to have preceded replication. The RNA world or era was the next evolutionary development. And how did this RNA world arise? As detailed in the same edition, lifeless viral particles may have served as mobile RNA-worlds which interacted with Russell's compartmentalized catalytic proto-cells to kick start life. Viruses may have later provided the direction which guided the trajectory of what would become replicating life. So what played the part of the first enzymes in the absence of direction; how did these entities take over from mere catalysis? According to Russell and colleagues once amino acids had formed within the cell-like compartments they could be induced to join up as short peptides driven by energy available in di- and tri-phosphates. As is now known, these are promoted in alkaline conditions. Once this energy was spent the phosphates could be recharged by the proton gradient acting across the walls to the compartments. At the same time the short peptides could wrap themselves around the phosphates, protecting them from dissolution and crystallization; a synergy between phosphate and peptides was born. The peptides could also enfold the metal sulfide clusters involved in electron transfer, hydrogenations and reductions; vastly improving their catalytic activities and approaching the activities of modern enzymes. Moreover the peptides could begin to take over the role of membrane and cell wall while still retaining the inorganic elements that quickened the slow geochemical reactions. However, certain organic ring compounds could have acted as catalysts or coenzymes too. Indeed, RNA molecules themselves such as ATP of which we each make our own body weight every day are vital to metabolism. In other words, early RNA had jobs to do before they became organized as information molecules. To condense RNA monomers to polymers required their concentration, through a diffusion process effected by the thermal gradient available at the hot spring. These RNAs operated first rather like retro-viruses they could travel between the cells making up the hydrothermal hatchery and those particularly adept at replication (through a convective polymerase chain reaction driven by the thermal gradient acting across the submarine hydrothermal mound) could survive to make DNA which made RNA which made proteins to take over from the simple peptides. These peptides could also play a part in maintaining homeostasis in the cell through an ingenious mechanism suggested by John Allen in the same edition, involving feed-forward as well as feed-back that afforded the cell a means of controlling its internal environment while adapting to the outside world. Evolution as a search engine for commensurate energy and nutrient niches was now possible, evolution as a euros �the survival of the most fitting on this, or any other wet, rocky and sunlit planet and in any galaxy. What this means is: we are not alone, and this is how life begins.
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