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Varanasi Thursday, 18 October, 2018 - 13:58

In a recent study published in the journal Microorganisms, researchers from the Banaras Hindu University, India, Rutgers University, USA, and Great Lakes Science Center, USA, have described a close association between microbes and plants that they live in, and how this relationship benefits both. The association, called the ‘rhizophagy cycle’, involves friendly bacteria and fungi that live in the roots of specific plants and help in nutrient transfer.

The term rhizophagy literally translates to 'root eating'. The bacteria and fungi involved in the rhizophagy cycle alternate between two phases—the endophytic phase where they live inside the roots of the plants, and the free-living phase where they live in the soil. The microbes acquire nutrients from the ground in the free-living soil phase. These nutrients are extracted from the bacteria by the plant when they live in its roots.

The researchers of the current study conducted experiments on several species of microbes to determine the details of the rhizophagy cycle. “Bacteria that function in the rhizophagy cycle belong to diverse classes, and it seems likely that any bacterium that colonises roots and can be induced to enter root cells, may be involved in the process,” they say.

The researchers informed that initially, the symbiotic microbes are attracted by the plants around their roots with the secretion of nutritious root exudates. The bacteria and fungi then enter the cells in the tips of the root and live in the space between the cell wall and the plasma membrane. When these cells mature, they secrete harmful reactive oxygen, which degrades some of the microbes inside, and the cells absorb the nutrients from them. Those bacteria and fungi that can survive the stress of oxidation trigger the formation of root hairs and come out from the roots.

Why then do plants eat the hands that feed them? “It seems probable that plants would not be internalising and degrading symbiotic microbes unless critical nutrients were being obtained from the consumption of those microbes”, remark the researchers.

Although we don’t yet know about the exact nutrients that plants acquire from the rhizophagy cycle, this process is crucial to the plants, the researchers hypothesise. “While rhizophagy has been shown to increase movement of nitrogen into plants, we hypothesise that the real benefit of the rhizophagy cycle may be in the acquisition of iron and other micronutrients from symbiotic microbes, although this must be proven”, they add. Other than the nutrients, the microbes also provide additional benefits like promoting development, resistance from disease and some other stresses.

Is there any benefit for the microbes in this entire process? “Microbes engage in the rhizophagy symbiosis likely because they also benefit from the nutrients provided by host plants. The rhizophagy symbiosis may be viewed as a mutualism involving an exchange of nutrients between the plant and microbe participants”, comment the researchers.

Section: General, Science, News Source: Link
Kottayam Thursday, 18 October, 2018 - 08:00

Carbon content in the soil is often used as an indicator of its richness in nutrients as carbon is essential for the healthy growth of plants. One way to increase soil nutrients is to use earthworms that feed on decaying organic matter in the soil. In a study, S. N. Sruthi and Prof. E. V. Ramasamy from the School of Environmental Sciences, Mahatma Gandhi University, Kottayam, report that the diversity of earthworms enriches the carbon content of the soil. The study was published in the journal Nature Communications and funded by Kerala State Council for Science, Technology, and Environment.

The researchers of the study spent twelve months observing the changes in the soil with and without earthworms. They marked out three plots of land, measuring 1 metre by 1 metre, in Jeevaka Live Laboratory—an area in the university campus with naturally varied vegetation and minimal human interference.

In the first plot, the researchers introduced about 100 earthworms of a native species and regularly fed water and cattle dung to the soil. They also fenced it with nylon mesh to a depth of 1 metre into the soil on all four sides to prevent the earthworms from migrating to the neighbouring plots. In the second plot, they added only water and dung and left the third plot as is. They then compared the changes in the biodiversity of earthworms and the properties of the soil over time of the three plots with three other plots of the same size outside Jeevaka lab in an area with a lot of human interference.

The researchers collected soil samples before beginning the experiment and once every three months afterwards. Soil organic matter acts as an essential reserve of plant nutrients in the soil and helps to retain more water. The results of the study found that both, the amount of organic matter and organic carbon, increased in all the three plots. The second plot, fed with just water and dung, showed the highest increase in these two quantities.

The researchers attribute this finding to the presence of more number and diversity of earthworms in the plot. “A majority of the earthworms in the first plot were the introduced species. Even though this plot received the same supplements, the nylon mesh might have restricted the entry of different varieties of earthworm”, they speculate. The earthworm diversity also influences the number of stable carbon particles available in the soil, which can stay in the soil for a decade or longer, the study found. The second Jeevaka plot showed the highest increase of about 50% in this quantity when compared to the other two Jeevaka plots. The three non-Jeevaka plots showed only about a 9% increase.

Besides, the presence of different types of earthworms also leads to increased microbial activity. In all six plots, there was an increase in the carbon content available from bacteria and fungi, which decompose the organic matter in the soil and release carbon dioxide needed for the plants. The second Jeevaka plot, which had the most diversity of earthworms, also showed the highest increase in microbial activity, which in turn increased the amount of easily decomposable carbon particles.

“Different types of microbial groups and their activity can enrich the soil with more carbon than a single group can”, add the researchers.

Earthworms lump together the carbon and organic particles decomposed by the microbes which make them last longer in the soil. Despite the increased consumption of carbon by the microbes in the second plot, it has better carbon content in the long term due to this interaction between the earthworms and microbes. “The diversity of earthworms influences the microbial activity in the soil, which in turn results in better carbon content in the soil. This can be further enhanced by regularly providing water and feed such as cattle dung”, say the researchers.

This study is the first to report an experiment exploring the role of earthworms in maintaining the carbon cycle in Indian soil. “The activity of a diverse group of earthworms can help the farmers sustain long-term stability of carbon in the soil without resorting to the use of chemical fertilizers”, conclude the researchers, talking about the implications of their findings.

Section: General, Science, Ecology, Deep-dive Source: Link
Bengaluru Wednesday, 17 October, 2018 - 10:23

कार्बनचाच एक प्रकार असलेला ग्राफीन हा पत्र्यासारखा द्विमितीय पदार्थ, विज्ञान आणि अभियांत्रिकी क्षेत्रात बराच हवाहवासा आहे. शास्त्रज्ञ त्याचे गुणधर्म तपासून त्यांचा उपयोग कसा करून घेता येईल  याचा अभ्यास करत आहेतच शिवाय हा पदार्थ तयार करायच्या कार्यक्षम व कमी खर्चाच्या पद्धती देखील शोधत आहेत. नुकत्याच प्रसिद्ध करण्यात आलेल्या अभ्यासानुसार, भारतीय तंत्रज्ञान संस्था मुंबई येथील प्राध्यापक राजीव दुसाने आणि डॉ. शिल्पा रामकृष्णन् यांनी नेहेमीच्या ठराविक पद्धतीपेक्षा कमी तापमानात आण्विक हायड्रोजनच्या मदतीने तांब्याच्या पत्र्यावर नॅनोग्राफीन आवरण तयार करण्याची नवीन पद्धत विकसित केली आहे.

२००४ मध्ये ग्राफीनची ओळख निर्विवादपणे पटल्यावर व ते सर्वप्रथम तयार केल्यापासून त्याचा मोठ्या प्रमाणावर अभ्यास चालू आहे कारण त्याचे यांत्रिक आणि विद्युतसंबंधित गुणधर्म विशेष आहेत. ग्राफीन तयार करण्यासाठी वापरलेले एक प्राथमिक तंत्र म्हणजे केमिकल व्हेपर डीपॉझीशन (रासायनिक बाष्प निक्षेपण). त्यासाठी कार्बन असलेले मिथेनसारखे संयुग १००० अंश सेल्सियस इतक्या जास्त तापमानाला तापवले जाते. उष्णतेमुळे कार्बनचे अणू मोकळे होतात आणि कार्यद्रव्य (किंवा सबस्ट्रेट - म्हणजे ज्या पदार्थाच्या पृष्ठभागावर क्रिया घडते तो) पट्टीवर जमतात. बहुतेक वेळेस योग्य औष्णिक गुणधर्मांमुळे तांबे हेच कार्यद्रव्य म्हणून वापरले जाते. 

मात्र या पद्धतीचा मोठा तोटा म्हणजे या पद्धतीत कार्यद्रव्यदेखील उच्च तापमानाला तापवून त्या तापमानाला टिकवून ठेवावे लागते. “उच्च तापमानामुळे इतर कोणत्याही प्रकारचे पदार्थ कार्यद्रव्य म्हणून वापरता येत नाहीत. तसेच उच्च तापमानाची गरज असणाऱ्या प्रक्रियेत साधनांच्या जुळणीचा आणि त्यांच्या निगराणीचा खर्च बराच असतो.” असे डॉ. शिल्पा सांगतात. मात्र हे तापमान कमी करणे योग्य ठरत नाही कारण कार्यद्रव्याचे तापमान कमी असेल तर जमलेला कार्बन अस्फटिक अवस्थेत राहतो आणि ग्राफीनचे स्फटिक तयार होत नाहीत.

पूर्वी झालेल्या अभ्यासावरून कोणत्याही कार्यद्रव्याच्या पृष्ठभागावर हिऱ्याचे आणि बहुवारिक (पॉलिमेरिक) पदार्थांचे आवरण जमा होण्यात आण्विक हायड्रोजनची भूमिका किती महत्वाची असते याची कल्पना आली होती. त्यावरून प्रेरणा घेऊन वरील संशोधकांनी तशाप्रकारची पद्धत वापरण्याचे ठरवले. त्यांचा हा शोधनिबंध मटेरीअल्स केमिस्ट्री अॅण्ड फिजिक्स या नियतकालिकात प्रसिद्ध झाला आहे. त्यांनी सांगितलेल्या पद्धतीनुसार तांब्याचे कार्यद्रव्य उच्च तापमानाला नेण्याऐवजी त्यांनी ते ६०० अंश सेल्सियस इतक्याच तापमानाला ठेवले आणि त्यावर २००० अंश तापमान असलेली टंगस्टनची तार ठेवली. मग त्या जुळणीतून मिथेन वायू सोडण्यात आला. याचा परिणाम म्हणजे अस्फटिक स्वरूपातील कार्बनचा एक थर तांब्याच्या पृष्ठभागावर जमा झाला. त्यानंतर टंगस्टनच्या तारेवरून हायड्रोजन वायू सोडण्यात आला. तेव्हा तेथे हायड्रोजनच्या अणूंचे विभाजन होऊन त्यांची अस्फटिक स्वरूपातील कार्बनबरोबर अभिक्रिया घडून आली आणि त्या कार्बनचे रुपांतर ग्राफीनमध्ये झाले.

संशोधकांनी सुचवलेल्या या पद्धतीला हॉट वायर केमिकल व्हेपर डीपॉझीशन (तप्ततार रासायनिक बाष्प निक्षेपण) असे म्हणतात. पारंपारिक पद्धतींपेक्षा ही पद्धत अनेक बाबतीत चांगली आहे. मिथेनच्या रेणूंचे विभाजन किंवा निक्षेपण होण्याची प्रक्रिया अत्यंत कार्यक्षम असते. त्यामुळे इतर पारंपारिक पद्धतींच्या तुलनेत या पद्धतीत बऱ्याच कमी तीव्रतेचा मिथेन वायू वापरता येतो. तसेच तार तापवायला लागणारी उर्जादेखील कमी असते. त्यामुळे एरवी ग्राफीनच्या वाढीसाठी लागणारे कार्यद्रव्याचे उच्च तापमान मोठ्या प्रमाणात कमी होण्यास मदत होते. या कारणांमुळे ग्राफीन निर्मितीचा एकूण खर्च कमी होतो.

तयार झालेल्या ग्राफीनचा नॅनो प्रमाणात अभ्यास केल्यावर असे दिसले की, हायड्रोजनची तीव्रता आणि संपर्काचा कालावधी कमीजास्त करून ग्राफीनची वाढ नियंत्रित करता येते. कार्यद्रव्य आणि कार्बन यांच्या परस्परप्रक्रियेऐवजी आण्विक हायड्रोजन वापरून ग्राफीनच्या आवरणाचे गुणधर्म शोधता यावेत यासाठीच्या अभ्यासात वरील संशोधनामुळे मदत होऊ शकते.

प्राध्यापक दुसाने आणि त्यांचे सहकारी यापुढे ग्राफीन निर्मितीची सर्वसमावेशक प्रक्रिया तयार करण्याच्या मागे आहेत. “आण्विक हायड्रोजनचे रासायनिक गुणधर्म वापरून कमी तापमानात हॉट वायर केमिकल व्हेपर पद्धतीने ग्राफीन निर्मितीची आणखी सुधारीत पद्धत तयार करण्याचा आमचा मानस आहे”, असे प्राध्यापक दुसाने म्हणतात.

Section: General, Science, Deep-dive Source:
Karnal Wednesday, 17 October, 2018 - 02:26

Interested in buffalo farming? Scientists from the National Dairy Research Institute (ICAR-NDRI), Karnal and the Indian Veterinary Research Institute (ICAR-IVRI), Izatnagar, may have good news for you! In a study published in the journal Theriogenology, they have described how some proteins present in the saliva of a female buffalo might help in detecting their estrus or mating stage.

Buffaloes are essential livestock for milk production in Southeast Asia and the Middle East. However, detection of the estrus in female buffaloes, which is crucial for insemination, is a complicated process. “Accurate and efficient detection of estrus is a key factor for right time artificial insemination and successful conception in buffaloes. This is a major constraint in buffalo as expressions of visible behavioural signs common during the mating time like bellowing, swelling and reddening of the vulva, and sniffing of genitalia are not very obvious in them,” say the authors of the study. The short span of the mating stage and changes in their sexual behaviour in different seasons make the detection all the more difficult.

The researchers studied 38 estrus cycles from 19 animals during the study. They collected saliva from these buffaloes during different stages of their estrus cycle, namely ‘proestrus’ or the stage before the onset of estrus, ‘estrus’ or when the female is sexually receptive, and the stages following the estrus called ‘metestrus’ and ‘diestrus’. The proteins isolated from the saliva samples were identified using a technique called nano-LCMS/MS—an efficient method for detecting proteins from a mixture.

The researchers identified hundreds of proteins from the saliva collected during different stages of the estrus cycle. Out of these, 31, 62, 32 and 104 proteins were found to be specific to proestrus, estrus, metestrus and diestrus stage of the estrus cycle respectively.

“The higher number of proteins in the estrus and diestrus stages suggest that the protein synthetic activity is induced during these stages in response to an increase in estrogen and progesterone hormone levels. These proteins might support the important processes of reproduction and embryonic development”, explain the researchers.

Some estrus-specific proteins like cullin associated NEDD8-dissociated protein 1, heat shock 70 kDa protein 1A, 17-beta-hydroxysteroid dehydrogenase type 1, inhibin beta A chain, and testin are essential for physiological processes related to reproduction. The researchers believe that these proteins might help in the accurate detection of estrus stage and understanding the buffalo reproductive biology in detail.

“The estrus specific proteins identified in this study could be explored further for their possible use as biomarkers for detection and confirmation of estrus in buffalo after thorough validation”, remark the researchers, about the implications of the findings.

Section: General, Science, News Source: Link
Pune Wednesday, 17 October, 2018 - 00:30

It was a little over a year ago. The two, in their twenties, were scouting the streets of Pune in the hunt for tubes and casings of different sizes. The idea? To construct an experimental setup to study fruit flies, aka Drosophila—the tiny little flies that appear out of nowhere to buzz around cut fruits and vegetables. Their objective—to figure out if a fruit fly’s sex, in association with other behavioural attributes, contributed to its inclination to disperse.

In a recent study, a team of researchers from the Indian Institute of Science Education and Research (IISER), Pune, have reported that  environment and evolution can influence the ‘dispersal syndrome’ in fruit flies. Dispersal syndrome is, simply put, all traits of an organism that are associated with its movement. Fascinated by this aspect of biology, researchers, led by Prof. Sutirth Dey from IISER Pune, have been studying dispersal syndrome in fruit flies. Their latest study was published in the journal Philosophical Transactions of The Royal Society B and was supported by the Department of Science and Technology, Government of India.

Dispersal syndrome provides clues about how an organism functions in a given habitat, which in turn answers much larger questions in the context of ecology and evolution, such as how wildlife survives in a world of climate change and habitat losses.

“The insights gained from such studies will not only have academic interest but will also appeal to practitioners of conservation and population management”, explains Mr. Abhishek Mishra, a research scholar from IISER Pune and an author of the study.

In their study, the researchers constructed a setup—long transparent tube connecting two containers on each end that could allow identification of the dispersers among the flies. “We still remember looking for plastic bottles and pipes of varying dimensions. Subsequently, cutting those bottles and fixing them with funnels were no less fun than performing the actual experiment”, laughs Sudipta Tung, also a research associate scholar at IISER Pune and an author of the study.

The researchers used this setup to breed flies for over 70 generations to study the dispersal syndrome over short and long timescales. The researchers built multiple such structures in the lab and then set out on the exhausting task of observing the flies, in batches, for dispersal. The experiments involved observations of sex-based disparity in the dispersal of Drosophila under low and normal nutrition. The scientists used low nutrition as a representation of a stressful situation that the flies could experience in their natural habitat. They assessed the flies’ body mass, resistance to drying up or desiccation, and even their exploratory tendencies—all as collective determinants of the complex composite function that is studied as ‘dispersal syndrome’.

The experiments led to a series of interesting observations. For instance, dispersive females were found to be more resistant to desiccation than their non-dispersive counterparts. However, no such trend was observed for males. “The most exciting result is that males and females can differ substantially in their dispersal syndromes and that these sex-specific differences can change with a change in the environment or with evolution,” says Sudipta. “Also, the dispersers had a higher desiccation resistance than non-dispersers when measured within a single generation, but after evolution (studied over 70 generations), the dispersers had evolved a lower desiccation resistance than non-dispersers”, chips in Abhishek.

These results enthuse evolutionary biologists to understand how and why animals disperse and are relevant in the context of deteriorating environments. In today’s world of deforestation, urbanisation, climate change, and worse, animals survive by resorting to dispersal in the hunt of a habitable space. Although one cannot directly extrapolate the study with Drosophila to endangered species such as the big cats, it does provide ecological clues about sex and dispersal syndromes that were hitherto unknown, which hold promise for a better tomorrow. 

Section: General, Science, Ecology, Deep-dive Source: Link
Mumbai Tuesday, 16 October, 2018 - 08:30

Prof. Vikram Vishal, Assistant Professor at the Department of Earth Sciences at the Indian Institute of Technology Bombay, was recently awarded the prestigious NASI Young Scientist Award - 2018 for his work on unconventional hydrocarbons. He is one of the 20 researchers across the country, to be awarded the annual prize for exceptional research in the field of Electronics, Engineering, Chemical Sciences, Physical Sciences and Plant Sciences.

The NASI Young Scientist award, instituted by the National Academy of Sciences India, recognises creativity and excellence in young scientists in India. The annual award carries a citation, a medal and Rs. 25,000 cash prize. Since 2006, 143 researchers across India have received the coveted award.

“NASI is the oldest scientific academy in India, and unlike several awards, the Young Scientist Award is highly competitive as the awardees come from different disciplines. I feel great about receiving the award,” says an elated Prof. Vishal.

Prof. Vishal’s current research, funded by the Ministry of Human Resource Development, focuses on unconventional hydrocarbon reservoirs in India. Unconventional hydrocarbon reservoirs are sources of oil and gas, that needs to be extracted using techniques different from the conventional extraction of hydrocarbons. Examples of these hydrocarbons include shale gas (natural gas trapped within certain fine-grained, fissile rocks called shales), shale oil, gas hydrates (a solid ice-like form of water containing gas molecules) and coal bed methane. His work proposes to estimate the shale gas potential for India accurately.

In their research, Prof. Vishal and his team of researchers mimic the conditions of the hydrocarbon reservoirs in their lab. They subject the collected shale samples to various conditions of temperature and pressure and estimate gas potential based on their observations. They predict a gas potential value of 25-30% more than that predicted by existing methods.

“Current shale gas estimates in India are not supported by field studies or experiments and do not have validated numbers. In this aspect, India is capable of producing best estimates through in-depth studies”, shares Prof. Vishal, who is also a recipient of the INSA Young Scientist Award for 2017. A combination of specialized techniques and expertise helps us understand these unconventional oil and gas sources.

“The recent efforts by the Government of India to explore unconventional hydrocarbon reservoirs such as shale gas and gas hydrates coincides with my expertise and interests. As a scientist, this laid the foundation for me to collect samples from various prospective basins in India and estimate the potential of natural gas as a future energy source. Exploiting even a small proportion of these reservoirs can serve the country for centuries”, adds Prof. Vishal. His work could help the country’s aspiration of reducing oil imports in the next five years and increase the country’s share to the natural gas contribution by 15 per cent by 2022.

Section: General, Science, News Source:
Brunei Darussalam Monday, 15 October, 2018 - 22:32

Forests, be it the Amazonian rainforests or the montane forests of the Western Ghats closer home, are astoundingly complex biological systems. For years, enthralled by this complexity, researchers have tried to understand the distribution of the world’s forests with the geography—a field of study called phytogeography. Till date, they have identified six floristic realms—geographical areas with a uniform composition of plant species—across the world, namely Afrotropical, Antarctic, Boreal, Holarctic, Neotropical and Paleotropical realms.

The advent of phylogenetics, or the study of evolutionary relationships among biological entities using genetic data, has aided in establishing new, evolutionary connections among several plant and animal species across the world. In a recent study, published in the Proceedings of the National Academy of Sciences (PNAS) of the United States of America, an international team of researchers have phylogenetically classified the world’s tropical forests into five principal floristic regions—Indo-Pacific, Subtropical, African, American and dry forests that include the famed forests of Andes ranges and Brazilian Cerrado.

“This study is different in the fact that for the first time a global classification of forests based on inventory data using phylogenetic (evolutionary) similarity between tree communities is produced", remarks Dr Ferry Slik, an Associate Professor at the Universiti Brunei Darussalam, Brunei Darussalam, and an author of the study. "The findings highlight historical similarity better than previous analyses that were based on just similarity in species, genus or family", he adds, talking about the novelty of this approach.

Previous classification systems often found the three main tropical continents—America, Africa and Asia—as separate biomes. America stood separated from Africa and Asia, and often there were distinctions between the classical 'New-world' and 'Old-world' tropics. "Our study links most African forests with American forests, while some are linked to Asian forests, i.e. the split runs through Africa”, explains Dr Slik.

The phylogenetic tree, proposed in the current study, included all flowering plants dating back to 140 million years. It was found that the plants from the Late Cretaceous period, as old as 100-66 million years, dominated the present-day tropical forests. The pattern of distribution is further explained by the breakup of an ancient supercontinent, Gondwanaland. The breakup of  Gondwanaland into present-day Africa, South America, Australia, Antarctica, the Indian subcontinent and the Arabian Peninsula, explains the connection between South American and African forests.

“The phylogenetic analysis just calculates the evolutionary distance in years since the last common ancestor between pairs of species in each tree inventory, gathering accurate information on the health and diversity of a forest. Based on that, you can calculate an average similarity between inventories, with more closer inventories having more species in common that split apart more recently”, elucidates Dr Slik.

In the 1970s, two famous botanists, Peter Raven and Daniel Isaac Axelrod, had proposed a link between Africa and America based on plant fossils. The current study provides evidence for the same, thereby confirming the relationship. Also, the study found indications for the existence of a global dry forest region with representative forests in America, Africa, India and Madagascar that are characterised by a deficit of rain and contain deciduous species. A northern hemisphere subtropical forest region was identified within representative field sites from Asia and America providing evidence for their forest linkages.

“There are still many things to discover about tropical forests”, says Dr Slik, adding that there are only a handful of studies that have compared global patterns in forests.

“Such comparisons are important because it has become clear that there are substantial regional differences in tree compositions and forest structure, which are linked to the separate historical developments of all these regional forests. If we can pinpoint these differences, we will also be much better in predicting how these forests will respond to things like climate change, forest fragmentation, and increasing levels of carbon dioxide. It clearly has significant policy implications as well, not just contributing fundamental biological knowledge”, he adds, talking about the implications of such studies.

Section: General, Science, Ecology, Deep-dive Source: Link
Pune Monday, 15 October, 2018 - 15:56

In a recent announcement, Dr Shekhar C. Mande, the current Director of the National Centre for Cell Science (NCCS), Pune has been appointed as the new Director General of the Council of Scientific and Industrial Research (CSIR) and the Secretary of the Department of Scientific and Industrial Research (DSIR), India. He succeeds Dr Girish Sahni, who retired on 31st August 2018. CSIR is one of the world’s largest publicly-funded research and development organisations and is known for its contributions in diverse areas of science.

Dr Mande is a leading structural and computational biologist and has more than 100 publications to his credit. His laboratory at NCCS has been involved in research on the structural characterisation of Mycobacterium tuberculosis proteins and the computational analysis of genome-wide protein: protein interactions.

After completing his M.Sc. in Physics from Nagpur University in 1984, Dr Mande obtained his PhD in Molecular Biophysics from the Indian Institute of Science, Bengaluru, in 1991 under the supervision of Prof. M. Vijayan. He started his postdoctoral research at Rijksuniversiteit Groningen, in the Netherlands in 1991 and joined as a senior fellow at the University of Washington, Seattle, USA in 1992.

After returning to India, he joined the Institute of Microbial Technology, Chandigarh, as a scientist and continued till 2001 when he was selected as a Staff Scientist at the Centre for DNA Fingerprinting and Diagnostics, Hyderabad. In 2011, Dr Mande was appointed as the Director of NCCS, Pune, an autonomous Institute of the Department of Biotechnology, Government of India. He also served in various advisory committees for the Government of India.

Dr Mande has several honours and awards to his credit. He is the fellow of all the three major science academies of India—the Indian National Science Academy (INSA), the National Academy of Sciences India (NASI), and the Indian Academy of Sciences (IAS). He received the prestigious Shanti Swarup Bhatnagar Prize for Biological Sciences in 2005.

Expressing his commitment to this new role, Dr Mande responded, “I am personally excited with this opportunity to work with great institutions...” and that “...CSIR will strive to contribute to the growth on Indian society, as it has gloriously done in the last 75 years.”

Section: General, Science, News Source:
Bengaluru Monday, 15 October, 2018 - 08:00

Looking up at the clear moonless sky gives one a glimpse of the breathtaking view presented by a part of our galaxy, the Milky Way, as a starry strip across the sky. Whether you are stargazing casually or observing with a pair of binoculars or a telescope, you are always in for a treat whenever you point your ‘eyes’ at the beautiful star clusters, nebulae and the dusty dark lanes. However, beyond the myriad stars and nebulae, exists a complex system of a star cluster near the massive black hole at the very centre of our galaxy. Most of these central ‘nuclear’ stars are old, but there are some young and luminous stars that appear to be distributed in a disc very close to the black hole. Unlike most other stars that are formed by dense clumps of molecular gas, these young stars are thought to have originated when the gas around the massive black hole fragmented to form locally dense regions. In this case, their orbits at formation would have been close to circular shape, inherited from the parent gas flow. But the young stars at the galactic center have orbits that are much more elongated or eccentric than expected.

In a recent study, researchers from the Raman Research Institute (RRI), Bengaluru and their collaborators at Leiden University, Netherlands, and the American University of Beirut, Lebanon, have delved deeper into the lives of these nuclear stars, and how gravity influences their orbits. They have identified instabilities, driven by the gravitational interactions between the stars themselves and the central black hole, which can drive a disc full of stars on nearly circular orbits into a state where the disc has more elongated orbits.

To describe how the change happens, we need to introduce the orbital energy and angular momentum of a star. The energy is a measure of the size of the orbit, and the angular momentum is a measure of how circular the orbit is. Astronomers study the orbits of stars in galaxies because the nature of the orbits of individual stars is one of the factors, which probe the internal structure of galaxies.

Physically, these orbits look oval-shaped with two centers or ‘foci’ with two unequal diameters called the minor and major axes. The degree of such elongation, known as the ‘eccentricity’ of the orbit, governs its shape. However, in the center of our Galaxy, a tightly packed system of many stars in their orbits interact with each other due to gravity, often leading to an exchange of their orbital angular momenta, while their semi-major axes which is the most extended radius, are constant. Thus, any decrease in the angular momentum of a star implies an increase in its eccentricity, causing these stars to have elongated orbits.

So, can gravitational interactions between the stars lead to an increase in the range of elongations of orbits as observed in our Galactic center? This question is difficult to answer since there are millions of stars in our Galaxy, and gravity is a long-range, purely attractive force. Hence, it is a challenge to disentangle the cumulative effect of each of these stars.

In this study, Dr. Karamveer Kaur and Prof. S. Sridhar from RRI, and their collaborators Mher Kazandjian from Leiden and Jihad Touma from Beirut, present a simple analytical model that tries to solve this question. The model assumes a razor-thin disc in which each star has an elliptical orbit with a massive black hole at one of its foci. Since the physical problem concerns exchange of angular momenta, they consider all the stars to have the same semi-major axis. So, in this model, each stellar orbit will have just its angular momentum and the angle along which it is elongated in the disc plane.

Since there are many stars in the disc, the researchers used a 'water bag' model to simplify the model.  A water bag model is analogous to water in a container having constant density inside but zero outside. Thus, despite all angles of elongation being equally probable in an initially circular disc of stars, this could evolve into a disc, which is non-symmetric about the axis (non-axisymmetric) wherein only some angles of elongation are more heavily represented.

The stellar orbits evolve over long timescales (though smaller than the average lifespan of stars) to result in a transformation from an initial planar configuration into a stable complex system of orbits with broad eccentricities. The critical part of this result stems from simulations performed using different combinations of angular momenta values and tracing the evolution of the model over different timescales. The simulations successfully demonstrated that the thin disc of stars experiences various non-axisymmetric, linearly unstable, long-term disturbances as a result of gravitational interaction between them. In the one particular case, it appears that the non-axisymmetric features eventually damp, and the disc settles into a new circular state, with a much wider distribution of eccentricities than in the original circular disc.

“The water bag instabilities for stellar discs are the first of their kind. Earlier known instabilities were mainly associated with counter-rotating systems. These non-axisymmetric instabilities open a way for stellar discs in the vicinity of massive black holes to accelerate in their eccentricity distribution on much shorter timescales. This phenomenon might be a possible channel via which stars in the young stellar disc at the galactic center got excited in eccentricities within their lifespan”, says Dr. Kaur, explaining their results in a nutshell.

The findings of the study have a crucial impact on our understanding of the Milky Way’s center and the processes that occur within it. An incredibly simple construct like this is a first step towards explaining the nature of the orbits of the nuclear stars. Exciting follow-up investigations are planned which would involve updating the disc models to mimic the real physical system, incorporating detailed properties of the nuclear stars like their ages.

“The assumption of a flat disc is a restriction that needs to be lifted to allow for fully three-dimensional stellar orbits. Our interest is to see if the eccentric instabilities we found will trigger inclination oscillations, perhaps leading to an eccentric and warped final state”, comments S. Sridhar, explaining the future research direction. 

Section: General, Science, Deep-dive Source: Link
Bengaluru Friday, 12 October, 2018 - 09:11

In a recent study, scientists have reported that the extract of the plant Toxicodendron pubescens, commonly called the Atlantic poison oak, could help alleviate neuropathic pain caused by nerve damage. The study included researchers from the R. C. Patel Institute of Pharmaceutical Education and Research, Kalinga Institute of Industrial Technology, SVKM’s Institute of Pharmacy, Janmangal Homeopathy and Wellness Centre and UAE University. It was published in the journal Scientific Reports.

Neuropathic pain is caused by damage or disease in parts of our nervous system perceiving various sensations. Thanks to the increase in the ageing population, survivors from cancer chemotherapy and the incidence of diabetes, this condition is now prevalent. Although there are a few anti-neuropathic drugs, they are not effective for pain management and pose various side effects. “The efficacy of available anti-neuropathic drugs is limited due to occurrence of several side effects and inadequate or delayed pain relief”, say the researchers.

For their study, the researchers, induced a neuropathic pain-like condition in laboratory rats by surgical lesions and treated them with the extract of the Atlantic poison oak. The extracts of the plant has been already used in alternative system of medicines, like homeopathy, for treating inflammatory conditions, rheumatic pain and typhoid fever. This is the first such attempt to test their efficacy on neuropathic pain.

What causes nerve injury and pain? Oxidative stress—an imbalance between harmful free radicals generated in the body and our ability to detoxify their effects, and inflammation, are some factors that could lead to nerve injury and persistent pain in the nerves. Enzymes like catalase, which catalyses the decomposition of hydrogen peroxide into water and oxygen, and superoxide dismutase, an antioxidant enzyme, protect us from oxidative stress by scavenging the harmful free radicals. When there is a nerve injury, the levels of these enzyme decrease in the body.

The study found that the extract of the Atlantic poison oak had antioxidant and anti-inflammatory properties that could alleviate neuropathic pain. When the injured rats were treated with the plant extract, it could revive the levels of catalase and superoxide dismutase. The researchers also observed that some cytokines (signaling molecules) of the immune system, which are released following nerve injury and contribute to the development of neuropathic pain, were also inhibited by the plant extract.

This study shows how the extract of Toxicodendron pubescens, also called Rhus Tox (RT), can help control neuropathic pain in laboratory rats. The researchers suggest the need for further pre-clinical and clinical studies to confirm its potential therapeutic use in humans.  “Results of the present study are suggestive of the effect of RT extract against neuropathic pain and deserve further validation of its effectiveness in various painful conditions”, conclude the researchers.

Section: General, Science, News Source: Link