8 results found containing all search terms.
... Science Frontiers ONLINE No. 58: Jul-Aug 1988 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Bacteria One dictionary's definition: "Widely distributed group of microscopic, one-celled vegetable organisms..." As a matter of fact, the nearly universal image of a bacterium is that of a simple, single-cell organism. But: "That view is now being challenged. Investigators are finding that in many ways an individual bacterium is more analogous to a component cell of a multicellular organism than it is to a free-living, autonomous organism. Bacteria form complex communities, hunt prey in groups and secrete chemical trails for the directed movement of thousands of individuals." J.A . Shapiro, author of ... , to form elaborate fruiting bodies." The Myxobacteria also collectively form baglike traps to engulf and digest prey. It is apparent now that as simple as a single bacterium may seem, bacterial colonies are pretty complex. (Shapiro, James A.; "Bacteria as Multicellular Organisms," Scientific American, 258:82, June 1988.) Comment. How are the collective actions of bacteria effected? Is there a central control center? Oh, oh! We are falling into the reductionist trap again! Life forms do not have to operate like computers do, nor do their functions have to be defined in those block diagrams we like so well. There may be holistic forces involved that escape reductionist thought. It is all very remarkable that bacteria which have been around for billions of ...
Terms matched: 2 - Score: 246 - 15 May 2017 - URL: /sf058/sf058b09.htm
... Science Frontiers ONLINE No. 96: Nov-Dec 1994 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects "ADAPTIVE" MUTATION Six years ago, J. Cairns performed experiments with bacteria that implied that said bacteria could "direct" their own mutations so that they could cope more speedily with sudden environmental trauma. (SF#64) In Cairns' experiments, bacteria unable to digest lactose were presented with an all-lactose diet. They quickly acquired the mutations needed to digest the only food available. They did not have to wait for random mutations to accidentally hit upon the correct genome changes. A firestorm spread across the scientific community, even though other researchers saw similar effects. It was traumatic! One of science's foundation stones ... at risk. The current theory of biological evolution insists that all mutations are random. Cairns believed he had shown that his bacteria experienced only useful mutations. This claim was too awful to accept. In the July 21, 1994, issue of Science, two new papers appeared that, while not proving that only useful mutations occur in Cairns-type experiments, do indicate that something unusual is indeed happening. Basically, when bacteria are under stress (say, starving), a "distinctive" type of mutation occurs! Is "distinctive" a code word for "non-random"? The title of the commentary accompanying the two articles says it all. (Culotta, Elizabeth; "A Boost for 'Adaptive' Mutation," Science, 265:318, 1994.) ...
Terms matched: 2 - Score: 213 - 15 May 2017 - URL: /sf096/sf096b08.htm
... amazing complexity of the seawater microcosm and its incredibly high microbe population density. The long strands in the oceanic gel are mostly crosslinked polysaccharides. If the polysaccharides in 1 milliliter of seawater could be placed end-to-end, they would stretch out to 5,600 kilometers! Coexisting proteins would span 310 kilometers ; DNA, 2 kilometers. This same milliliter may also contain up to a million bacteria and ten times as many virus particles. Also in this brew are, on the average, 1.000 protozoans and 100 phytoplankton. It's a microscopic metropolis, about the size of a sugar cube, and one in which you may never wish to swim again! The polysaccharides and proteins that comprise most of the thin goo are not alive, although the bacteria are. Just ... changes our ideas of the microcosmos in which sea organisms live. It has added another layer of complexity that people are only now starting to consider in the context of whole ocean systems . . Gel is like the dark matter of the sea. While sea gel does not impede the snorkeler, . it does herd microbes into clumps or microniches . which we cannot see either. These microbes. in effect, exist in a tangled. 3-D mesh that affects not only their movements but also those of their prey and predators. A few statistics confirm the amazing complexity of the seawater microcosm and its incredibly high microbe population density. The long strands in the oceanic gel are mostly crosslinked polysaccharides. If the polysaccharides in 1 milliliter of seawater could be placed end-to-end, they ...
Terms matched: 2 - Score: 175 - 15 May 2017 - URL: /sf134/sf134p09.htm
... Science Frontiers ONLINE No. 15: Spring 1981 Other pages Home Page Science Frontiers Online All Issues Last Issue Next Issue Sourcebook Project Sourcebook Subjects Contents Archaeology Basques in the Susquehanna Valley 2,500 Years Ago? Invention of Agriculture May Have Been A Step Backward Hidden Stonehenge Atlantis Found -- again Astronomy Distant Galaxies Look Like Those Close-by "tired Light" Theory Revived Those Darn Quarks Biology If Bacteria Don't Think, Neither Do We The Evolutionary Struggle Within Geology Is All Natural Gas Biological in Origin? Iceland and the Iridium Layer Geophysics The Novaya Zemlya Effect Massive Ice Lump Falls on England Psychology Is Your Brain Really Necessary? ...
Terms matched: 2 - Score: 168 - 15 May 2017 - URL: /sf015/index.htm
... their graph covering the past 70 years which speaks for itself. You can add the 1990 flu outbreak to the curve yourself! To strengthen the correlation Hoyle and Wickramasinghe tabulate flu and sunspot data back to 1761. They find that flu pandemics and sunspot maxima have kept in step for the last 17 cycles. Key to the Hoyle-Wickramasinghe argument is their contention that simple life forms (viruses, bacteria, etc.) not only exist in outer space but likely evolved there. If so, how do they ride in to afflict us on the peaks of the solar cycle? Here's how, in their words: "In conclusion, we note that electrical fields associated with intense solar winds can rapidly drive charged particles of the size of viruses down through the exposed upper atmosphere into ... shelter of the lower atmosphere, the charging of such particles being due to the photoelectric effect. This could define one possible causal link between influenza pandemics and solar activity." (Hoyle, F., and Wickramasinghe, N. C.; "Sunspots and Influenza," Nature, 343: 304, 1990.) Reference. Periodic epidemics are cataloged in BHH3 in: Biological Anomalies: Humans II. To order, visit: here . From Science Frontiers #68, MAR-APR 1990 . 1990-2000 William R. Corliss ...
Terms matched: 2 - Score: 156 - 15 May 2017 - URL: /sf068/sf068b11.htm
... river, called the Ganga by the Indians. Despite this heavy burden of pollutants, the Ganges has for millennia been regarded as incorruptible. How can this be? Several foreigners have recorded the effects of this river's "magical" cleansing properties: Ganges water does not putrefy, even after long periods of storage. River water begins to putrefy when lack of oxygen promotes the growth of anaerobic bacteria, which produce the tell-tale smell of stale water. British physician, C.E . Nelson, observed that Ganga water taken from the Hooghly -- one of its dirtiest mouths -- by ships returning to England remained fresh throughout the voyage. In 1896, the British physician E. Hanbury Hankin reported in the French journal Annales de l'Institut Pasteur that cholera microbes died ... The Ganges The Ganges is 2525 kilometers long. Along its course, 27 major towns dump 902 million liters of sewage into it each day. Added to this are all those human bodies consigned to this holy river, called the Ganga by the Indians. Despite this heavy burden of pollutants, the Ganges has for millennia been regarded as incorruptible. How can this be? Several foreigners have recorded the effects of this river's "magical" cleansing properties: Ganges water does not putrefy, even after long periods of storage. River water begins to putrefy when lack of oxygen promotes the growth of anaerobic bacteria, which produce the tell-tale smell of stale water. British physician, C.E . Nelson, observed that Ganga water taken from the Hooghly -- one of its dirtiest ...
Terms matched: 2 - Score: 156 - 15 May 2017 - URL: /sf094/sf094g11.htm
... magnetic crystals is obscure. The favored explanation is that the hornets use them as guides during nest construction -- sort of like those little flags human surveyors set out. This explanation assumes that hornets can somehow sense and make use of the complex magnetic field created by an array of many tiny magnets. Another question asks where the magnetic crystals come from. Do the hornets secrete them like the magnetotactic bacteria or do they gather them from their environments? (Stokroos, Ietse, et al; "Keystone-Like Crystals in Cells of Hornet Combs," Nature, 411:654, 2001.) Comment. It would be so easy to dismiss the hornets' little crystals as just one more animal gee-whiz fact, but we should not. Did the hornets first recognize that magnetic ... than light. To achieve the high accuracy needed to home in on small rodents in the black of night, their ears are slightly offset so that they can draw a bead by using microsecond time-of-arrival differences in the sounds coming from the target. To increase the owl's passive sonar, their auditory neurons multiply the signals instead of adding them as do other neurons. In effect, they create an "auditory map" of their surroundings. On their high-precision auditory maps, a rustling mouse would be highlighted. So far, though, biologists have not learned how neurons can multiply signals. The asymmetrical design of the Barn Owl's ears is essential for pinpointing its prey in the dark. (From: Biological Anomalies: Birds) (Helmuth, Laura ...
Terms matched: 2 - Score: 145 - 15 May 2017 - URL: /sf138/sf138p04.htm
... Science Frontiers ONLINE No. 119: Sep-Oct 1998 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects The black death and ccr5-delta 32 Plagues are not all bad, and the Black Death (bubonic plague) that swept into Europe from Asia in 1346 was no exception. It is now common knowledge that bacteria, insects, plants, and even humans can build up resistances to poisons, diseases, and antibiotics. Mutations are always occurring; some good, some neutral, some bad. It has been found that a human mutation designated CCR5-delta 32 confers immunity to AIDS if inherited from both parents. People carrying the CCR5-delta 32 mutation lack the receptors to which the AIDS virus must attach itself if it is to ... something must have occurred about that time to greatly favor the survival of people carrying the mutation." What biological catastrophe decimated Europe 700 years ago? The Black Death. One-quarter to one-third of the Europeans succumbed between 1347 and 1350. The Black Death strongly modified the European gene pool, increasing the frequency of CCR5-delta 32. This mutation may not have had any direct effect on the plague itself. It may just be a quirk of fate that the survivors of the Black Death had a higher frequency of the CCR5-delta 32 mutation, and it is doubly quirky that the mutation confers a resistance to AIDS, which is a recent human affliction. About 10% of whites of European origin now carry the CCR5-delta 32 mutation. The incidence is only ...
Terms matched: 2 - Score: 144 - 15 May 2017 - URL: /sf119/sf119p05.htm
