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SciAm blogger wonders: Complex life owes its existence to parasites?

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However, a new piece of research offers an intriguing (albeit equally unproven) alternative. Zhang Wang and Martin Wu of the University of Virginia make an argument that instead of a chancy cellular merger, or engulfment of one prokaryote by another, the mitochondrial machinery actually comes from a parasite. What started out as a bacterium stealing chemical energy eventually became an organism providing chemical energy – in return for an evolutionary advantage.

This proposal comes from a deep look at the genetic relationships between modern mitochondria and 18 closely related free-ranging bacteria. The researchers in effect attempt a reconstruction of the likely metabolic processes of the earliest mitochondria and their immediate precursors. They find that these critters were more likely to have been chemical energy parasites, and probably mobile too – with genes for the bacterial ‘tails’ or flagella that propel many microbes. More.

Seriously, The Science Fictions series at your fingertips (origin of life)

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OT: Stephen Meyer teaching a Biblical history class: A Tale of Two Conquests - Stephen Meyer - video (Biblical History) https://www.youtube.com/watch?v=NcDNYXmUWO0 Seminar by Dr. Stephen Meyer Bear Creek School, Redmond WA September 2014 bornagain77
Of related interest, crev.info has this recent article up: Cell Biologists Use Machine Language - October 23, 2014 http://crev.info/2014/10/cell-machine-language/ bornagain77
of related interest to 'mitochondrial machinery' is this recent piece of news: Shaking up cell biology - October 20, 2014 Excerpt: a team of scientists,,, has imaged mitochondria for the first time oscillating in a live animal,,, “The movements could last from tens of seconds to minutes, which was far longer and frequently at a faster tempo than observed previously in cell culture,” said Roberto Weigert, Ph.D.,,, The mitochondria also appear to synchronize their movements not only in an individual cell but, quite unexpectedly, into a linked network of oscillators vibrating throughout the tissue. “You look through the microscope, and it almost looks like a synchronized dance,” said Weigert. “The synchronization, to borrow an old cliché, tells us that we need to differentiate the forest from the trees — and vice versa — when studying mitochondria. It may be that the forest holds the key to understanding how mitochondria function in human health and disease.” The mitochondrion (the singular of mitochondria) is of one of several distinct compartments, or organelles, in the cell cytoplasm. Although mitochondria are jacks of many biochemical trades, they are best known as the power plants of the cell. They generate a continuous supply of the molecule ATP that, like bits of coal, serve as the cell’s main source of energy to power the heart to beat, muscles to stretch, and virtually every movement that the body makes. ,,, http://www.nih.gov/news/health/oct2014/nidcr-20.htm a few more notes: Your Rotary Engines Are Arranged in Factories - August 2011 Excerpt: As if ATP synthase was not amazing enough, a team of scientists in Germany now tells us they are arranged in rows with other equipment to optimize performance. From electron micrographs of intact mitochondria, they were able to detect the rotary engines of ATP synthase and other parts of the respiratory chain. Their diagram in an open-source paper in PNAS looks for all the world like a factory.,,, “We propose that the supramolecular organization of respiratory chain complexes as proton sources and ATP synthase rows as proton sinks in the mitochondrial cristae ensures optimal conditions for efficient ATP synthesis.” The authors had virtually nothing to say about how this might have evolved, noting only that the structure is “conserved during evolution” in every sample they examined (3 species of fungi including yeast, potato, and mammal). What this means is a lack of evolution over nearly two billion years, in the standard evolutionary timeline. http://crev.info/content/110817-your_rotary_engines_are_arranged_in_factories Mighty Mitochondria Conduct Energy Exquisitely - October 2011 Excerpt: ,,,Mitochondria have inner and outer membranes. The inner membranes are folded into protrusions called cristae that increase their surface area. With the help of transporter machines, the mitochondrion takes in molecules (glucose, pyruvate, and NADH) from the cytosol into its outer and inner membranes into the interior where, with the aid of oxygen and a large number of enzymes and cofactors, electrons are transferred to oxygen through five complexes of machines. The first three, called NADH dehydrogenase (Complex I), cytochrome c reductase, and cytochrome c oxidase, provide an “electron transport chain” that is used to pump protons into the space between the mitochondrion’s inner and outer membranes. The protons return through the inner membrane via the fifth machine, the turbine-like rotary motor ATP synthase (see CMI), which uses the proton motive force generated by the other machines to synthase ATP. Although cells can generate ATP without oxygen (anaerobic respiration), producing it through the mitochondrial machinery is much more efficient. On a busy day you produce approximately your body’s weight in ATP.,,, http://crev.info/content/111007-mighty_mitochondria Nanomachines in the Powerhouse of the Cell: Architecture of the Largest Protein Complex of Cellular Respiration Elucidated - July 2010 Excerpt: In biological oxidation, the energy will be released by the membrane bound protein complexes of the respiratory chain in a controlled manner in small packages. Comparable to a fuel cell, this process generates an electrical membrane potential, which is the driving force of ATP synthesis. The total surface of all mitochondrial membranes in a human body covers about 14,000 square meter. This accounts for a daily production of about 65 kg of ATP. (A little over 143 pounds). The now presented structural model provides important and unexpected insights for the function of complex I. A special type of “transmission element,” which is not known from any other protein, appears to be responsible for the energy transduction within the complex by mechanical nanoscale coupling. Transferred to the technical world, this could be described as a power transmission by a coupling rod, which connects for instance the wheels of a steam train. This new nano-mechanical principle will now be analysed by additional functional studies and a refined structural analysis. http://www.sciencedaily.com/releases/2010/07/100702100414.htm Powering the Cell: Mitochondria - video http://www.youtube.com/watch?v=RrS2uROUjK4 Researchers discover protein that shuttles RNA into cell mitochondria - August 2010 Excerpt: Without this RNA import, the cell lacks the machinery to assemble the mitochondria's energy source, Koehler said.,, Mitochondria are fantastically complex and our study reveals another cellular pathway in which these tiny but important powerhouses participate in essential cell activities, such as the generation of energy essential for life." http://www.physorg.com/news200306498.html bornagain77

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