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DNA chip for ophthalmic diagnosis Prof Yash
Pal
This Universe Trends |
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How butterflies fool ants IT sounds like one of Aesop’s fables but the story of the blue butterfly and the red ant is probably not one you would like to send your children off to sleep with. The caterpillar of the blue butterfly is “adopted” by the red ant which takes the butterfly larva back to its nest where it treats it like one of its own brood, feeding it until it is old enough to turn into an adult butterfly.
The caterpillar, however, repays the ant’s generous hospitality by greedily eating as much food as it can and gobbling up the ant’s offspring as a tasty side dish. All five species of large blue butterflies in Europe engage in this form of parasitism on red ants and now scientists have worked out the trick that allows them to do it. The caterpillars cover themselves in a chemical that makes them smell like orphaned baby ants. Researchers have found that the organic molecules secreted on the skin of the blue caterpillars closely match those on the skin of the red ant larvae. What is more, the closer the chemical cocktail is, the stronger the attraction of the ant to the caterpillar. The findings should help conservationists in their attempts at reintroducing large blue butterflies, which are endangered, by making sure the chemistry of the caterpillars and the ants match each other as closely as possible. David Nash of the University of Copenhagen, who led the study published in the journal Science, said the results were a vivid demonstration of the evolutionary “arms race” that can escalate between parasites and their hosts. “Parasites are always trying to better adapt to their hosts, to parasitise them, whereas their hosts are experiencing selection pressures to avoid being parasitised,” Dr Nash said. “It means there can be an ongoing evolutionary arms race between the parasite and its host. There have been some previous studies on microscopic organisms showing this can occur in the laboratory but what we have here I think is one of the first cases where we have clear evidence that this has been happening out in the field.” The scientists studied dozens of red ant colonies on an island off the Danish coast and, in each nest they examined, they counted the number of caterpillars of the Alcon large blue butterfly that they found living there Alcon blue butterflies lay their eggs on the marsh gentian plant and its caterpillars grow in the usual way by feeding on the plant’s leaves. But, at the fourth stage of growth, the caterpillars gently lower themselves to the ground on silken threads. “The caterpillars first start developing on a food plant but once they reach a certain stage they leave the food plant and wait on the ground to be discovered by one of these ants,” Dr Nash said.
— The Independent |
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DNA chip for ophthalmic diagnosis IN a development of great significance to the medical diagnosis, the Bangalore based Xycton has designed and developed a DNA chip that can successfully zero in on the pathogens causing ophthalmic disorders and diseases with a high degree of accuracy in a very short period of time. This innovative DNA chip named XCyto Screen could easily and precisely detect as many as 15 pathogenic micro-organisms, including virus, bacteria and fungus, all of which cause severe damage to the ophthalmic region. According to Dr Ravi Kumar, Chairman and Managing Director of Xcyton, “the technology is a combination of nucleic acid amplification and genome based DNA micro array and helps in the simultaneous detection of multiple pathogens, something not done so far”. This efficient diagnostic tool was developed by Xycton with the support of many research institutions and medical establishments, including All India Institute of Medical Sciences (AIIMS), Shankara Nethralaya, Chennai, L.V.Prasad Eye Institute, Hyderabad and Kidwai Memorial Institute of Oncology, Bangalore. In fact, many American universities, academic institutions and genetic engineering firms have been exploring the possibility of using the protein derived from the primitive bacteria E. Coli popularly called the workhorse of the genetic engineering to develop a chip capable of increasing the data storage capability of a computing machine by a substantial extent. As it is, for millions of years now, this primitive bacteria has been in the business of protein synthesis-the basis of life process-much the same way as the modern day computer does the job of information processing and data analysis with quiet efficiency. The quest of researchers working on biological computer is to use the bacterial protein-in conjunction with transistors and printed circuit boards-as a potential substitute for the seemingly irreplaceable silicon chips. Sometime back a group of researchers at the Bangalore based Indian Institute of Science (IISc) had covered much ground in developing a biochip based on bacterial protein. The objective of this path-breaking project was to build a biochip that would increase the memory level and storage capacity of a computer. Clearly and apparently, computers falling back on high performance biochips could easily help close the gap between the processing speed and storage capacity. |
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This Universe
How are glass and water transparent? They too have a lot of mass. LET
us be clear. What you are asking is the reason for visible light going through glass and water without significant attenuation. But glass and water do not allow X-rays to go through. They are also not transparent to infrared radiation. This latter we know because a closed car sitting in the sun becomes very hot. This is because while light comes in through the glass windows the infrared, or heat radiation cannot go out as easily. This is the so-called green house effect. Our atmosphere has a thickness of about 1000 grams per centimetre square. This is almost like half a metre thick wall of carbon, yet it does not present too much of an obstacle to visible light — we can see the sun, the moon and the stars. But the same atmosphere is not very transparent to x-rays, gamma rays or infrared. It also protects us from the ultraviolet from the sun and, of course, from energetic cosmic rays. There are particles like the neutrinos that can go through the earth billions of times without making a hit. It is clear therefore that the stopping power against a form of radiation does not depend only on the mass of material. It also depends on the structure of the material: this structure defines the band of radiation that it can absorb or scatter. This structure is atomic and molecular in nature. Glass and water do not have strong absorption bands in the wavelength of light that form the visible region or its spectrum. In the end I might mention that glass, water and air are not completely transparent to visible light. There is molecular scattering that leads to the production of our blue skies, blue colour of the sea and pitch darkness at the bottom of the ocean, and less than perfect transmission in ordinary optical fibers used for optical communication. Why petrol and related substance alone have the property of fuel? Petrol, oil, coal and would contain elements that combine with easily available oxygen in the atmosphere to produce some other products. These materials are called hydrocarbons.
It means they contain hydrogen and carbon. Hydrogen can combine with oxygen and so can carbon. The product might be water or carbon dioxide but both reactions are highly exothermic, meaning energy releasing. So the secret lies in the fact that abundant oxygen is available and combination of oxygen with these substances produces heat and energy. Talking of dreams there are people who are making plans for converting mars into an earthlike planet. It is not so different in size and does show evidences that at one time it had lot of water flowing on its surface. If human kind really wants to make mars into an earth like planet, with plants, atmosphere rain and clouds, it will have to use biological means and it might take a few centuries if not a few millennia. I am not sure we have enough patience or cooperation for projects like this. We only think in terms of military bases and ways of dominating and conquering others. I personally think there is a lot to be done here on earth if only we will. We have to remember that it is impossible to think of a habitat that contains only one species. Even we are not just one species alone. We would not be possible if we did not have within us a large number of other species inhabiting the world within us in a symbiotic relationship. All these would have to be sustainable in a planet that behaves like our earth. Just remember that even the earth had to be prepared by early life to come to a state where we became possible.
For example oxygen in our atmosphere is a gift of that early life. This is not to say that there was a conscious attempt to prepare for our arrival. We just happened, that also very recently. Thus a lot will have to happen before mars becomes and autonomous earth like planet. Who knows it might even happen in a few thousand years. |
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Trends “In primate societies, grooming is the underlying fabric of it all,” Dr. Michael
Gumert, a primatologist at the Nanyang Technological University in Singapore, said in a telephone interview Saturday. “It’s a sign of friendship and family, and it’s also something that can be exchanged for sexual services,” Gumert said.
— AP
Ethanol from prairie grass New research shows that prairie grasses grown using only moderate amounts of fertiliser on marginal land can produce significant amounts of ethanol. The five-year study of switch grass done by the University of Nebraska and the USDA’s Agricultural Research Service was published this week by the National Academy of Sciences. Researcher Ken Vogel said he estimates that an acre of switch grass would produce an average of 300 gallons of ethanol based on the study of grass grown on marginal land on farms in Nebraska, South Dakota and North Dakota.
— AP Fingerprinting diamonds The phosphorescence comes from boron in the gem, the same element that makes it appear blue in normal light, explained Jeffrey Port, curator of the National Gem Collection at the Smithsonian’s National Museum of Natural History.
— AP |
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The famed Hope Diamond glows a mysterious red when exposed to ultraviolet light, a finding that scientists say can help them “fingerprint” blue diamonds and tell the real ones from the artificial.