9 results found.
... Science Frontiers ONLINE No. 92: Mar-Apr 1994 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects The World Before Our World Genetically speaking, modern terrestrial life is bilingual in the sense that it employs two chemical languages. Function is written in the 20 amino-acid "alphabet" of proteins, while information is conveyed in sequences of four nucleotide "letters" called codons. We need go no further with the genetics lesson because our purpose here is to speculate a bit about the monolingual world that is believed to have preceded ours. This older world is commonly termed the "RNA World." It was and is monolingual because both function and information are carried on a single molecule. It is customary to call the RNA World "prebiotic," meaning that it was all chemistry and no life. But, one does wonder whether that was all there was to it. Catalysis and replication of genetic information occurred in the RNA World. What besides a chemical soup might have existed before "life-as-we-know-it" arrived upon the scene? A science fiction writer like H.P . Lovecraft could certainly come up with an ominous entity based upon RNA alone. Be that as it may, a book is now on the market bearing the title The RNA World (R .F . Gesteland and J.F . Atkins, eds., Cold Spring Harbor Laboratory Press, 1993) Nature reviewed the book in its January 20 issue. In addition, the RNA World was discussed recently in ...
Terms matched: 1 - Score: 109 - 15 May 2017 - URL: /sf092/sf092b07.htm
... Science Frontiers ONLINE No. 47: Sep-Oct 1986 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Earth's womb Three recent items indicate that scientists are now recognizing how the earth's crust is tailor-made for biochemical reactions of great variety and complexity. First, E.G . Nisbet explains how subsurface hydrothermal systems are ideal places to make biochemical products, particularly in the light of the discovery that RNA molecules can extrude introns and then behave like enzymes. "The most likely site for the inorgan ic construction or an RNA chain, which would have occurred in the Archaean, is in a hydrothermal system. Only in such a setting would the necessary basic components (CH4 , NH3 , and phosphates) be freely available. Suitable pH (fluctuating around 8) and temperatures around 40 C are characteristic of hydrothermal systems on land. Furthermore, altered lavas in the zeolite metamorphic facies, which are rich in zeolites, clays and heavy metal sulphides, would provide catalytic surfaces, pores and molecular sieves in which RNA molecules could be assembled and contained. If the RNA could then replicate with the aid of ribozymes and without proteins, the chance of creating life becomes not impossible but merely wildly unlikely." The article concludes with a statement that self-replicating molecules synthesized in hydrothermal systems would be pre-adapted to "life" in the open ocean if they "learned" to surround themselves with bags of lipids. (Bag of lipids = a membrane.) (Nisbet, E.G .; " ...
Terms matched: 1 - Score: 65 - 15 May 2017 - URL: /sf047/sf047p11.htm
... code for multiple variants of the same protein. And many proteins are modified by adding sugar molecules, which play a big role in determining where proteins go and what they do. What's more, different proteins can join together to carry out completely new functions. (Ref. 2) A group of French biologists, led by Francois Jacob and Jacques Monod showed that the gene's boundaries are fuzzier than had been thought and that genes are not restricted to chromosomes. Recently, biologists have found genes within genes, overlapping genes, and DNA sequences that specify one protein when read "forward" and another when read "in reverse." Muddling things further, the instructions encoded in the DNA do not always reach the ribosome as a literal translation. In a phenomenon known as RNA editing, an enzymatic highwayman intercepts the RNA message en route and alters it, so the resulting protein is not identical to that specified by the DNA. (Ref. 3) We can sum up by saying that a lot can happen to that information encoded in the genome before it is put to use. References Ref. 1. Anonymous; "The Flexible Genome," Nature, 411:xi, 2001. Ref. 2. Coghlan, Andy; "Privatising Your Proteins," New Scientist, p. 5, April 14, 2001. R3. Comfort, Nathaniel C.; "Are Genes Real? Natural History, 110:28, June 2001. From Science Frontiers #139, Jan-Feb 2002 . 2001 William R. Corliss Other Sites of Interest ...
Terms matched: 1 - Score: 25 - 15 May 2017 - URL: /sf139/sf139p05.htm
... Science Frontiers ONLINE No. 25: Jan-Feb 1983 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Learning By Injection The following abstract is taken from the Psychological Record. "In an attempt to replicate previous findings that learned information could be transferred from trained donor animals to untrained recipient animals by means of brain extracts, two groups of rats were trained to approach a food cup in response to a discriminative stimulus (click or light). RNA extracted from the brains of these animals was injected intraperitoneally into untrained rats. The two untrained groups showed a significant tendency to respond specifically to the stimulus employed during the training. The results support the conclusion that acquired behaviors can be transferred between animals by transferring brain DNA, and further suggest that the transfer effect is dependent upon and specific to the learning of the donors." (Oden, Brett B., et al; "Interanimal Transfer of Learned Behavior through Injection of Brain RNA," Psychological Record, 32:281, 1982.) Comment. Of course, morphogenic fields, as described in R. Sheldrake's A New Science of Life, could also explain this effect. From Science Frontiers #25, JAN-FEB 1983 . 1983-2000 William R. Corliss ...
Terms matched: 1 - Score: 24 - 15 May 2017 - URL: /sf025/sf025p05.htm
... Science Frontiers ONLINE No. 13: Winter 1981 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects The Alien Presence Hidden behind an obscure technical title is a most curious discovery. I.C . Eperon and his coworkers at the MRC Laboratory of Molecular Biology, England, have shown that "human mitochondria did not originate from recognizable relatives of present day organisms." The authors go even further, describing human mitochondria as a "radical departure." (Eperon, I.C ., et al; "Distinctive Sequence of Human Mitochondrial Ribosomal RNA Genes," Nature, 286:460, 1980.) Comment. The inferences above may be far-reaching. Mitochondria are vital components in the cells of the so-called higher organisms. Apparently possessing their own genetic material, they are suspected of being descendants of an cient bacteria that invaded and took up residence in cells. If human mitochondria are radically different, could changes in mitochondria be the source of the purported wide gap between humans and other animals? Did the mitochondria change (" evolve") in existing ancient mammals, converting them suddenly into humans? Or did a new "species" of mitochondria infect terrestrial cells, perhaps coming to earth on cosmic debris, as Fred Hoyle has suggested? From Science Frontiers #13, Winter 1981 . 1981-2000 William R. Corliss ...
Terms matched: 1 - Score: 15 - 15 May 2017 - URL: /sf013/sf013p10.htm
... Science Frontiers ONLINE No. 105: May-Jun 1996 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects The Nether Universe Of Life Bacteria well-adapted to high temperatures have been brought up from oil wells thousands of miles apart. All indications are that these bacteria are indigenous to the wells; that is, not introduced by the drilling fluids. What is most interesting is the fact that these bacteria are all closely related despite their remoteness from each other. They not only look and behave alike, but they also share 98.2 % of their 16S ribosomal RNA sequences. M. Magot asks what an anomalist would ask. "For example, where are these bacteria from? How did they succeed in colonizing these habitats?...Are these microorganisms directly descended from bacteria that were trapped during the formation of the oil, or accompanied its migration through tens to hundreds of millions of years? Did they arrive in the oil field later as a consequence of aquifer activity? What is their mode of maintenance and development in their environment?" (Magot, Michel; "Similar Bacteria in Remote Oil Fields," Nature, 379:681, 1996) Comment. Bacteria have also been extracted from mineral-charged fluids circulating in drill holes over 12 kilo meters deep and also in deep aquifers. There must be an unexplored universe of life thriving not only beneath our feet but also - quite possibly - beneath the forbidding surface of Mars. Reference. Examples of life thriving at great depths in the earth may be found ...
Terms matched: 1 - Score: 15 - 15 May 2017 - URL: /sf105/sf105p08.htm
... simple memory, the brain will quickly use up all available cells. It must be that individual brain cells can participate in the storage of many different memories. The conventional mem-ory-trace theory would have to be replaced by a new type of memory architecture. (Bower, Bruce; "Million-Cell Memories," Science News, 130:313, 1986) Comment. Our thinking about biological memory may be controlled by our preoccupation with the two-dimensional circuits of computer memories. Biological memories might be three-dimensional, or of even higher order. Some scientists have ventured that memory might entail electrical charge distribution patterns in the brain; such need not be limited to two dimensions. The same thinking can be applied to the storage of genetic information. While DNA, RNA, etc., may be pieces in the puzzle, the complete solution may include the ways in which these molecules are bent, twisted, convoluted, arrayed, juxtaposed, and so on. In a letter relating to the above article, P.J . Rosch points out that John's results are consistent with the holographic theory of brain function supported by Pribram and Bohm. "In a hologram, every element of the subject is distributed throughout the photographic plate, making it possible to reconstruct the entire original image from any portion of the picture. In this paradigm, the brain stores memory and deals with interactions by interpreting and integrating frequencies, retaining the data not in a localized area but dispersed throughout its substance." (Rosch, Paul J.; "The Brain ...
Terms matched: 1 - Score: 14 - 15 May 2017 - URL: /sf049/sf049p10.htm
... maps that were drawn up so hastily in the bitterly contested race between the publically and privately sponsored programs? How good are those computer programs that identified these 30,000 or so genes? According to W. Haseltine, who heads Human Genome Sciences, "They're reading smudged text through foggy glasses." Haseltine's company claims to have found more than 90,000 human genes. Two other organizations have identified between 60,000 and 65,000 genes. A research group at Ohio State University at Columbus analyzed the same data used by the public consortium and estimates that there are actually human 80,000 genes! In fact, this groups avers, the public consortium's software seems to have missed 850,000 gene segments for which there already exists protein or RNA evidence. The human genome map seems to harbor many terrae incognitae. So, we best not draw profound conclusions just yet. (Kintisch, Eli; "So What's the Score?" New Scientist, p. 16, May 12, 2001.) Errors. The genome-mapping efforts of both the public consortium and private company (Celera) depended heavily upon computers and software. That errors may have crept into Celera's map of the human genome via their software is suggested by analysis of Celera's earlier map of the fly genome. The same "shotgun" approach was employed in both efforts. When S. Karlin, at Stanford, began using the fly genome map he spotted many errors. He has said, More than 60 per cent of ...
Terms matched: 1 - Score: 14 - 15 May 2017 - URL: /sf136/sf136p06.htm
... Inheritance of Acquired Characters was not indicated. It is true that Steele has proposed a Darwinian interpretation of his findings, but his theory adds a startling new dimension to the development of life. In essence, Steele asserts that an organism's immunological system is really the evolutionary scenario in miniature and compressed in time. The body's immuno-logical system is trying to cope with up to 10 million defensive cells. The only defensive cells that survive and multiply are those that happen to encounter an invader that they can lock onto and destroy. The "fittest" defensive cells are those that have just the right characteristics to knock off invaders, and only they survive permanently in the body's defensive arsenal, giving it acquired immunity. The Lamarckian part of this story occurs when the RNA of the selected defensive cells gets passed on to the organism's progeny. (Tudge, Colin; "Lamarck Lives -- In the Immune System," New Scientist, 89:483, 1981.) Comment. The picture evolving here is one of a hierarchy of evolutionary struggles -- say, humans on one level and their contained defensive cells on another level. The levels are not completely independent. The question that arises next is whether there are other evolutionary struggles going on, possibly in the mitochondria and chloroplasts, which possess their own genetic material. Or, waxing speculative, are there hierarchies of evolutionary struggle above humanity of which we know nothing except for perhaps a few anomalies representing cross talk between levels? From Science Frontiers #15, Spring 1981 . 1981- ...
Terms matched: 1 - Score: 14 - 15 May 2017 - URL: /sf015/sf015p09.htm
