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Snowfall in Himalayas decreasing
Chemistry comes closer to biology
Application-oriented research ‘self-defeating’
New drug against TB soon
Ribosomes key to new antibiotics
Hydrogen sulphide: toxic yet therapeutic
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Snowfall in Himalayas decreasing The 98th Indian Science Congress held at SRM University in Kattankulathur, Chennai, brought together a galaxy of scientists, including Nobel laureates. N Ravikumar reports For those enjoying the snow fall in the Himalayan region now, a leading scientist who is observing the Himalayan cryosphere, says that what they are seeing now is probably lesser than the snow fall which occurred a few decades ago. Presenting a paper titled “Response of Himalayan Snow and Glaciers to Climate Change” at the 98th Indian Science Congress, a leading scientist, Dr Anil V Kulkarni, said Himalayan cryosphere was witnessing a decrease in snow fall and increase in temperature. The decreasing snow fall had resulted in depleting snow cover in the Himalayas and this was indicated by an algorithm developed using AWiFS sensor of Indian remote sensing satellite, Kulkarni, a scientist with the Indian Institute of Science, Bangalore, said. Normalised Difference Snow Index (NDSI) technique, which uses the unique spectral characteristics of snow, which has high reflectance in visible region and low reflectance in short wave Infrared Region, was utilised to overcome the cloud and snow problems, he said. Many basins of the Himalayas had shown large amounts of snow cover depletion in early part of winter (from October to December); he said and added that the average steam runoff off the Baspa basin during the month of December showed an increase by 75 per cent. Dr Kulkarni said the satellite based techniques had also shown that most of the Himalayan glaciers were retreating, though the rate of retreat varied from glacier to glacier. Estimates had shown an overall reduction in glacier area from 6,332 to 5,329 sq km., a deglaciation of over 16 per cent. The study also suggested that the Himalayan glaciers had lost 21 metre of ice from 1972 to 2010, he said and added that this observation was supported by the change in snow line altitude at the end of ablation season on the Chhota Shigri glacier from 4,900 to 5,200 metre from late 1970 to 2010. “This combination of glacial retreat, negative mass balance and early melting of seasonal snow cover suggested an influence of climate change on the Himalayan cryosphere. Many Himalayan rivers including Indus, Ganges and Brahmaputra originate from the snow and glacier bound regions. This source of water should not be considered permanent, as geological history of the Earth suggests constant variations in glacial extent due to climate”, he warned. |
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Chemistry comes closer to biology The most important frontiers of chemistry today are related to biology and advanced materials and the emphasis of chemists in this century is more on materials and biology and less on molecular chemistry, CNR Rao, a prominent Indian scientist said .
Rao, chairman of Jawaharlal Nehru Centre for Advanced Scientific Research, who delivered a lecture titled “Chemistry of future,” said that the contributions of chemists to biology, environment, health and medicine had become so crucial and synthesis and development of new materials of desired properties had come to the fore. Every few years, a major discovery of a new molecule or a new material with unusual properties trigger chemical research in a big way. High temperature cuprate superconductors, mesoporous silica, fulerenes and nanotubes were typical examples, Rao said. The beginning of modern chemistry was in 1930 when it was thought that structure formed the basis of everything in chemistry. When molecular conformation got recognised to be an important aspect of chemistry in 1969, new methods for the study of molecular structure came to the fore, he said. Chemists had used spectroscopies, diffraction methods and microscopes and Four modern discoveries, high temperature superconductors (1986), synthesis of new carbon forms (1990), mesoporous solids (1992) and colossal magnetoresistance (1993) were the major achievements in materials chemistry. Rao said superconductors became chemicals after 1987 and solid state chemistry got to be recognised as part of main stream chemistry. After the year 2000, there had been a change as to how one viewed chemistry. The main challenges before chemical sciences in the 21st century would be new synthesis, self assembly and complex chemistry. The major areas of chemistry today were chemical and physical transformations of matter, imaging structures, chemical theory and computer modelling, interface with biology and medicine, materials by design, atmosphere and environment and energy. The cause of the ozone hold was discovered through chemical research, Rao said and added that climate change, monsoons and other aspects of the environment and atmosphere could be understood and modelled only on the basis of the chemical processes involved. It would be important to pursue dynamics of chemical reactions involved in causing pollution, brown clouds and global warming, he said and stressed |
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Application-oriented research ‘self-defeating’ Slamming the tendency of governments and universities to lay more stress on “Translational” (application-oriented) research, Nobel laureate Dr Martin Chalfie said it will be “detrimental and self-defeating”.
Delivering a lecture on “Adventures in non-translational research” he said in recent years government officials and university administrators had called for a greater emphasis on “translational research” over basic research. Translational research emphasises studies that apply or translate findings in the laboratory into new treatments for medical conditions. Chalfie, a biologist at the Columbia University, USA, said “Although the applications of biological and bio-chemical research to human disease, agriculture and industry was very important, I feel that the current, increased emphasis is not needed and is actually detrimental”. Recalling his own experience in developing Green Flourescent Proteins (GFP), which is used as a biological marker in studying nerve cell development, he said “non-translational” (basic) research was important for its own sake. Explaining the condition of biological research before his discovery of GFP. He said most observations of gene activity or protein localisation before 1990s were done on dead specimens that were specially prepared and permeabilised to allow entry of reagents to stain cell components. These methods allowed a glimpse of what cells were doing, but they gave a necessarily static view of life, just a snapshot in time, he said and added that most cellular processes could not be easily followed. GFP and other fluorescent proteins revolutionised the biological sciences because they allowed scientists to look at the inner workings of living cells. GFP could be used to tell where genes turned on, where proteins were located within tissues and how cell activities changed over time. |
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In what will be good news for thousands of tuberculosis patients throughout the world, Nobel laureate and Molecular Biochemist Dr Thomas A Steitz has said the recent success in the determination of “ribosome complexed with three tRNAs” could enable the development of new derivatives of tuberoctinomycins that would be effective against the alarming drug resistant TB strain, XDR.
Explaining the functioning of the new antibiotics, he said they bind near to the decoding centre (of bacteria), interacting with both the large and small subunits as well as the tRNA. The antibiotics being developed would be different from the earlier antibiotics paromomycin and hygromycin, since its binding site (the position where the drug attacks the bacterial structure) would be adjacent to those of earlier antibiotics. Throwing light on the research being done at the highest level and another effective antibiotic which is being developed, the scientist said a compound derived from linazolid and sparsomycin had completed phase II clinical trials successfully. This compound was proving effective against all resistant strains of bacteria that had been tested. Raising alarm over the rapid rise in antibiotic drug resistant bacteria around the world in recent decades, Steitz said new families of antibiotics that could combat the growing threat to human health posed by antibiotic resistant bacteria were being developed due to the recent successes in structural studies of ribosomes. He said over 50 per cent of antibiotics target the bacterial ribosome and most of them inhibit the functioning of the large ribosomal subunit. Outlining the history of research in ribosomes, he said the initial research ribosome structural studies were done on the large ribosomal subunit that was isolated from the archaeal bacteria called Haloarcula marismortui (Hma). The atomic structure of the large subunit and its complex with a substrate analogue published in 2000 showed a tightly packed RNA with the globular domains of the proteins scattered on the surface and non-globular loops of 14 proteins imbedded within the RNA interior, he said. Recalling the assumption of scientist Francis Crick in 1968 that ribosome was indeed a ribozyme, he said the assumption was later proved since proteins did not participate in the catalysis. The crystal structures of many complexes of the large subunit with different families of antibiotics had shown their mechanisms of inhibition of ribosome function as well as the sources of antibiotic resistance, Dr Steitz said. Explaining how the antibiotics attacking a particular site in the bacterial structure was developed and major macrolide resistance mutations occurred through structural modifications, he said new potential antibiotic compounds were being developed using computational chemistry. Computational chemistry was used to design and evaluate many new possible modifications of the hybrid compounds and then new compounds were synthesised and their effectiveness measured. |
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Ribosomes key to new antibiotics Venkatraman Ramakrishnan, the Nobel laureate of Indian origin, today said understanding the structure of ribosomes would be the key to produce new and effective antibiotics to diseases caused by bacterial infections. Scientists throughout the world were working to find new antibiotics since the existing ones were becoming ineffective due to the resistance developed by the disease-causing bacteria, he said. About two million deaths were caused in the world every year due to tuberculosis and scientists were trying to understand the structure of ribosomes, so that new and effective antibiotics could be found. Underlining the significance of ribosomes, he said. In all life forms, ribosomes use the instructions present in genes to make proteins. Proteins catalysed most of the vast array of chemical reactions in the cell and were thus essential to life. “Ribosomes are large macromolecular machines consisting of roughly two-third RNA (Ribo Nucleic Acid) and one-third protein and consist of almost half a million atoms in bacteria”, he said. Ramakrishnan said ribosomes were also the target of a large number of clinically important antibiotics.
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Hydrogen sulphide: toxic yet therapeutic Hydrogen sulphide is known to be toxic for living organisms for more than two centuries. However, a recent study has shown that it may be of therapeutic benefit as it is a novel and efficacious endogenous bronchodilator. This will be more effective than nitric oxide and carbon monoxide as a gaso-transmitter, as “it is highly soluble in aqueous and lipid milieu and eminently membrane permeable”, said Dr NL Stephens, a Canadian scientist working at University of Manitoba. “We have conducted studies on canine tracheal smooth muscle and used sodium-bi-sulphide dissolved in the nutrient solution to generate hydrogen sulphide. Equilibrium with the tissue was attained in 20 minutes. The hydrogen sulphide-generating enzyme was distributed in airway smooth muscle,” Maximum isometric force development, isotonic, shortening capacity and velocity of shortening were significantly reduced by hydrogen sulphide treatment, he said. The reduction in isotonic shortening induced by hydrogen sulphide suggested that it be of therapeutic benefit in sensitised airway smooth muscle, which showed increased capacity and velocity of shortening in the past, Dr Stephens added. All regular columns have been held over this week because of the special coverage provided in today's issue. The columns will resume from next week.
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The 98th Indian Science Congress held at SRM University in Kattankulathur, Chennai, brought together a galaxy of scientists, including Nobel laureates. N Ravikumar reports
For those enjoying the snow fall in the Himalayan region now, a leading scientist who is observing the Himalayan
cryosphere, says that what they are seeing now is probably lesser than the snow fall which occurred a few decades ago.
“More recently, we have determined the structure of the whole ribosome complexed with three tRNAs and either capreomycin or viomycin-antibiotics that are effective against tuberculosis”, Dr Steitz, a scientist working at the Yale University and Howard Hughes Medical Institute said. He was delivering a lecture titled: “From the structures of ribosome complexes to new antibiotics”.