////////////////The extraordinary role of viruses in evolution and how this is revolutionising biology and medicine. Darwin's theory of evolution is still the greatest breakthrough in biological science. His explanation of the role of natural selection in driving the evolution of life on earth depended on steady variation of living things over time -- but he was unable to explain how this variation occurred. In the 150 years since publication of the Origin of Species, we have discovered three main sources for this variation -- mutation, hybridisation and epigenetics. Then on Sunday, 12th February, 2001 the evidence for perhaps the most extraordinary cause of variation was simultaneously released by two organisations -- the code for the entire human genome. Not only was the human genome unbelievably simple (it is only ten times more complicated than a bacteria), but embedded in the code were large fragments that were derived from viruses -- fragments that were vital to evolution of all organisms and the evidence for a fourth and vital source of variation -- viruses. Virolution is the product of Dr Frank Ryan's decade of research at the frontiers of this new science -- now called viral symbiosis -- and the amazing revolution that it has had in these few years. As scientists begin to look for evidence of viral involvement in more and more processes, they have discovered that they are vital in nearly every case. And with this understanding comes the possibility of manipulating the role of the viruses to help fight a huge range of diseases.
About the Author
Originally qualified as a doctor, Frank Ryan is now one of the pioneers of the role of viruses in evolution. He was recently made Honorary Research Fellow in the Department of Animal and Plant Sciences at the University of Sheffiled, with the express purpose of developing his evolutionary concepts and helping to translate evolutionary science into medicine. He is the author of four general books, including a New York Times NON-FICTION BOOK OF THE YEAR (Tuberculosis).
/////////////////AGGRESSIVE SYMBIOSIS
////////////////Elysia chlorotica is a small-to-medium-sized species of green sea slug, a marine opisthobranch gastropod mollusc. This sea slug superficially resembles a nudibranch, yet it does not belong to that suborder of gastropods. Instead it is a member of the closely-related suborder Sacoglossa. The suborder Sacoglossa are known as the 'sap-sucking Opisthobranchias'. Many members of this group use chloroplasts from the algae they eat; a phenomenon known as kleptoplasty. Elysia chlorotica is one of the "solar-powered sea slugs", utilizing solar energy via chloroplasts from its algal food. It lives in a subcellular endosymbiotic relationship with chloroplasts of the marine heterokont alga Vaucheria litorea. Elysia chlorotica are most commonly found in salt marshes, tidal marshes, pools and shallow creeks along the east coast of the United States. They are often found as far north as Nova Scotia and as far south as Florida.
////////////////////ANGKOR VAT-900-1400-THEN DECLINE-
////////////////////1994-HANTAVIRUS EPIDEMIC IN US
/////////////////MAMMALS ARE MAIN RESERVOIR OF VIRUSES
//////////////GENOME IS SUM TOTAL OF ALL GENES OF AN ORGNSM
////////////////VIRUS IS A PIECE OF BAD NEWS WRAPPED UP IN A PROTEIN
/////////////////It’s Alive
In the December issue of “Scientific American,” Luis Villarreal examines the debate concerning biological viruses and evolution.2 He notes that although there is still much to be learned about how and whether these agents evolve, the impact they have had on the world around them (and in turn the evolution of other biological systems) should be analyzed. This article takes the same approach, introducing the possibility of “evolution” and computer viruses and how these virtual agents affect the world around them. Viruses are analyzed from two fronts: how they react to external forces and how they act as a catalyst for changing their environment, namely the Internet.
Does malware evolve? The use of the term “evolution” when describing a virus certainly elicits the notion that they adapt to changes on their own, something that most people would concede does not happen.3 Although some polymorphic worms do change their appearance, this is constrained by routines coded into the program. Viruses, however, do change quite frequently; a worm may become much more potent (or destructive) based on the improvements made by its author. Virus coders learn from previous releases and computer technology improves, both of which provide an author with new tools from which to build malware. In this way, viruses are much more about innovation than evolution.
/////////////////VIRUS-HORIZONTAL GENE TRANSFER
/////////////////////////Cryo-electron microscopy reconstruction of a poliovirus-receptor-membrane complex
Doryen Bubeck1, David J Filman2 & James M Hogle1, 2
1 Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, Massachusetts 02138, USA.
2 Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Correspondence should be addressed to James M Hogle james_hogle@hms.harvard.edu
To study non-enveloped virus cell entry, a versatile in vitro model system was developed in which liposomes containing nickel-chelating lipids were decorated with His-tagged poliovirus receptors and bound to virus. This system provides an exciting opportunity for structural characterization of the early steps in cell entry in the context of a membrane. Here we report the three-dimensional structure of a poliovirus−receptor−membrane complex solved by cryo-electron microscopy (cryo-EM) at a resolution of 32 Å. Methods were developed to establish the symmetry of the complex objectively. This reconstruction demonstrates that receptor binding brings a viral five-fold axis close to the membrane. Density is clearly defined for the icosahedral virus, for receptors (including known glycosylation sites) and for the membrane bilayer. Apparent perturbations of the bilayer close to the viral five-fold axis may function in subsequent steps of cell entry.
//////////////////Our genome is the sum of all the DNA that makes us human.
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