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Bengaluru Tuesday, 25 September, 2018 - 19:20

In the last few years, there has been a surge of new species discovered and described from the Western Ghats—one of the world's hottest biodiversity hotspot. For instance, so far in 2018, we have three new species of frogs and one snake from this region! Thanks to the systematic sampling of the landscape and modern molecular techniques, we are now starting to have a better picture of the richness of this ecosystem. In one such effort through four years of field work, scientists from the Indian Institute of Science, Bengaluru, Bombay Natural History Society (BNHS), Mumbai, Oklahoma State University, USA, and The Natural History Museum (NHM), London, have discovered two new species of lizards in the Western Ghats.

In the study, published in the journal Zootaxa, the researchers have used an integrative taxonomic approach that combines molecular analysis, geographical distribution and physical characteristics of the lizards. They have also reassessed the nomenclature of all the species of lizards of the genus Calotes found in the Western Ghats. The study was supported by the Critical Ecosystem Partnership Fund (Western Ghats), the Department of Biotechnology and the Ministry of Environment and Forests (MoEF).

The 27 known species of lizards of the genus Calotes, which includes the forest lizards and garden lizards, are spread across South and Southeast Asia and parts of China, with the Western Ghats in Peninsular India being a hotspot for several of them. This study splits Calotes into three genera while describing two new species.

“There has been no substantial taxonomic work on most of the agamid lizards from Peninsular India since they were initially described more than 150 years ago. Back then, taxonomy was only based on morphological observations of specimens with very less understanding of the ecology and biogeography of these groups. Hence, superficially similar-looking agamids were grouped together in the genus Calotes", remarks Mr. Saunak Pal from BNHS, who is the lead author of the study.  "Now, with a widespread geographical study and use of molecular tools, we have a better understanding of the relationship of these lizards”, he adds.

Based on genetic and physical similarities and differences between the different species of lizards, the researchers of the study created an evolutionary tree—a branching diagram showing the evolutionary relationships among different species in the group. They found four evolutionary groups among agamid lizards of Peninsular India, two of which (Microauris and Monilesaurus) were earlier thought to be a part of the genus Calotes. They found that both of them were endemic to the Western Ghats and described them as new genera in this study.

The genus Microauris was named after the Latin word ‘auris’ meaning ear, referring to the extremely small tympanum these lizards have. The tympanum is an external hearing structure present in mammals, birds and some reptiles. At present, this genus has only one species, Microauris aurantolabium, which can be distinguished from other lizards as it has the smallest tympanum. The other genus, Monilesaurus, was named after the Latin word ‘monile’ meaning necklace, referring to the distinct neck fold found in the individuals of this genus, and the Greek word ‘sauros’ meaning lizard. Species belonging to this genus can be identified by the presence of a characteristic fold of skin on their neck.

The two new species discovered by the researchers belong to the genus Monilesaurus, and are named Monilesaurus acanthocephalus and Monilesaurus montanus. M. acanthocephalus are olive-red coloured lizards with a distinct long spine behind their eye, light brown head and, red and black blotches on their body. They are currently known from high elevation evergreen forests and along the forest-tea garden edges of the Megamalai hills of the southern Western Ghats.

The other species, M. montanus, named after the word ‘montane’, are restricted to the high elevation forests 1500m above the sea level, as their name suggests. These yellowish-green lizards have alternating light and dark brown patches on the back and are found in the high elevation evergreen forests of Kudremukh, Brahmagiri, Nilgiri and Elivalmalai.

The researchers believe that pre-monsoon might be a breeding season for this species. Both these species are diurnal in habit. “Nothing much is known about the behaviour of these new lizards other than that they are arboreal and have small distributional ranges restricted to the high elevations of the Western Ghats.”, says Mr. Pal.

While recent advancements in taxonomic tools and techniques have helped a systematic study on the evolutionary history and biogeography of many species, there is still a long way ahead for these lizards to be in the limelight. “While frogs of the Western Ghats are often in the news with the discovery of many new species, reptiles have received less attention. There is, however, a substantial diversity of lizards and snakes in the Western Ghats as well”, remarks Mr. Pal, talking about what could still be unexplored in the forests.

The researchers believe there is a host of exciting things the lizards can bring to the board. “This study signifies the lack of understanding of the evolutionary relationships among Indian reptiles and shows that we still need a lot more systematic research on Indian agamids, especially for the widespread but ignored groups like the Rock Agamas and those occurring in the North East. Along with morphology, we also need to study the distribution and molecular phylogenies to understand the relationship and evolution of lizards”, signs off Dr. Deepak, a co-author of this study from NHM.

Section: General, Science, Ecology, Deep-dive Source:
Bengaluru Tuesday, 25 September, 2018 - 12:19

In an exciting recent study, researchers have reported an accidental encounter of a male praying mantis (Hierodula tenuidentata), eating a guppy fish  (Poecilia reticulata) in Karnataka. Although mantises are known to attack small vertebrates, the addition of fish to their menu, as reported in the study published in the Journal of Orthoptera Research, is the first such documented evidence. 

Mantises are a group of insects which mostly feed on other insects. The name ‘praying mantis’ comes from the distinctive way they raise their forelegs, as if in prayer. They have a voracious appetite and are, at times, referred to as ‘preying mantis’. They usually sit and wait for their prey, but fishing is a behaviour that is considered unusual.

In an accidental encounter, researchers saw the male mantis, about 5.6 cm long, visiting the roof garden continuously for five consecutive days looking for its prey. A small, artificial pond in the garden had some fish. The water lilies and water cabbage that were on the surface of the pond helped the insect to sit and hunt its prey. The researchers observed that the insect consumed nine fishes in five days, and disappeared after that.

Many studies in the past have indicated that the eyes of the mantises are adapted to vision mostly in daylight. However, the present observation, where the mantis was seen hunting in the night with low light, could add a new dimension to their visual abilities. Besides, the fact that these insects could feed on fish has a remarkable significance on the pond ecosystem.

“Our observation shows the potential for a single invertebrate to have a strong impact on the fish community and indirectly on the whole pond ecosystem as small fishes like guppies are active predators of aquatic insects”, say the researchers.

The other interesting observation from the study was the repeated predation behaviour of the mantis where it was seen hunting for the fish from the same location. Although mantises are known to possess basic learning abilities like avoiding a toxic prey, this observation indicates a more elaborate hunting strategy that these insects might have learned from different environmental clues. There are also earlier reports of mantises that know how to select an area for hunting.

The researchers believe that their findings could open up the possibility for other studies exploring this behaviour of mantises. “Remembering the prey’s abundance at a particular site in relation to their ease of capture and their nutritional content could be one important factor helping these insects and may indirectly influence individual fitness. This should be investigated in further studies”, conclude the researchers.

Section: General, Science, Ecology, News Source:
Tuesday, 25 September, 2018 - 11:08

স্বাস্থ্য ৰক্ষাৰ ক্ষেত্ৰত পৰিষ্কাৰ খোৱাপানীৰ যথেষ্ঠ অৱদান আছে। লেতেৰা খোৱাপানী সেৱনৰ ফলত বিভিন্ন ধৰণৰ বেমাৰ যেনে ক’লেৰা, ডায়েৰীয়া, গ্ৰহনী, টাইফয়েড আৰু জণ্ডিছ আদিয়ে দেখা দিব পাৰে। ভাৰতৰ দৰে দেশ এখনত পৰিষ্কাৰ পানীযোগানৰ প্ৰতি বিশেষ মনোযোগ দিয়াটো অতি প্ৰয়োজন কাৰণ ইয়াত ২১ শতাংশ সংক্ৰমণশীল বেমাৰ লেতেৰা খোৱাপানী সেৱনৰ ফলতে হয় আৰু প্ৰতিদিনে প্ৰায় পাচশঁতকৈও বেছি ল'ৰা ছোৱালীয়ে ডায়েৰীয়াৰ ফলত মৃত্যুবৰণ কৰে । বৈজ্ঞানিক আৰু উদ্যোগিক অনুসন্ধান পৰিষদ (চি এচ আই আৰ) ৰ অধীনস্থ ভাৰতীয় বিষবিজ্ঞান অনুসন্ধান সংস্থান (আই আই টি আৰ) দ্বাৰা উদ্ভাবিত এটা নতুন পৰিশোধন যন্ত্ৰই খোৱাপানীৰ সমস্যা যথেষ্ট পৰিমানে লাঘৱ কৰিব বুলি আশা কৰা হৈছে।

বিভিন্ন ধৰণৰ পৰিশোধন যন্ত্ৰ (ফিল্টাৰ) বজাৰত সহজলভ্য, কিন্তু বেছিভাগ ফিল্টাৰেই অতি ব্যয়বহুল। চি এচ আই আৰৰ দ্বাৰা উদ্ভাবিত অ’নীৰ নামৰ এই ফিল্টাৰটো কিন্তু বাকীবোৰতকৈ অলপ ব্য়তিক্ৰম | সৌৰ শক্তিৰ দ্বাৰা চালিত এই ফিল্টাৰটোৱে মাত্ৰ দুই পইচাতে এক লিটাৰ পৰিষ্কাৰ খোৱাপানীৰ যোগান ধৰিব পাৰিব। এই ফিল্টাৰটোৱে পানীত থকা জীৱাণু সমূহ ধংশ কৰাৰ উপৰিও লেতেৰা ঘোলা পানীও পৰিশোধন কৰিব পাৰিব।

ৰিচাৰ্ছ মেটাৰ্চৰ সৈতে হোৱা এক সাক্ষাৎকাৰত ভাৰতীয় বিষবিজ্ঞান অনুসন্ধান সংস্থানৰ (আই আই টি আৰ) নিৰ্দেশক প্ৰফেছৰ আলোক ধাৱানে জনায় যে “এই ফিল্টাৰটোৱে ‘এন’ডিক অক্সিডেচন’ প্ৰক্ৰিয়াৰ দ্বাৰা কাম কৰে। এই অভিনৱ প্ৰক্ৰিয়া টোৱে বেমাৰ সৃষ্টি কৰিব পৰা ভাইৰাচ, বেক্টেৰিয়া, ভেকুৰ, প্ৰ’ট’যোৱা আদি নিৰ্মূল কৰিব পাৰে। পৰিষ্কাৰ খোৱাপানীৰ বাবে বিশ্ব স্বাস্থ্য সংস্থাৰ দ্বাৰা নিৰ্ধাৰিত, ৰাষ্ট্ৰীয় আৰু আন্তৰাষ্ট্ৰীয় মানদণ্ড অনুসাৰে সেৱা আগবঢ়াবলৈ ই কাৰ্যক্ষম।”

অ’নীৰৰ দুটা সংস্কৰণ বনোৱা হৈছে, এটা ঘৰত ব্যৱহাৰৰ উপযোগী আৰু আনটো ব্যৱসায়িক প্ৰয়োগৰ কাৰণে। ঘৰুৱা সংস্কৰণটোৱে পাচ মিনিটত দহ লিটাৰ পানী পৰিশোধন কৰিব পাৰে। ব্যৱসায়িক ভিত্তিত প্ৰয়োগ হবলগীয়া সংস্কৰণটোৱে এক ঘণ্টাত ৪৫০ লিটাৰ পানী পৰিশোধন কৰে। পৰিশোধনৰ সীমা ঘণ্টাত ৫০০০ লিটাৰৰ পৰা এক লাখ লিটাৰ লৈকে উন্নীত কৰিব পৰা যাব। মজাৰ কথাতো হ’ল যিহেতু এই ফিল্টাৰটো সৌৰশক্তিৰ দ্বাৰাও চালিত হয়, গতিকে, বিদ্য়ুত যোগান নথকা গাওঁসমূহ আৰু ৰাস্তাৰ কাষৰ অস্থায়ী দোকানসমূহতো এতিয়া বিশুদ্ধ পানী উপলব্ধ হ’ব।

যিহেতু এই ফিল্টাৰটিত অতিৰিক্ত চেকনীৰ প্ৰয়োজন নহয় গতিকে সঘনাই চেকনী সলনি কৰিবলগীয়া হোৱা সমস্যাটোৰ পৰা অ’নীৰৰ গ্ৰাহকসকল মুক্ত হ’ব । প্ৰফেছৰ আলোক ধাৱানে জনায় যে “ফিল্টাৰত লাগি থকা চেন্সৰে পৰিশোধন প্ৰক্ৰিয়াৰ অৱস্থাটোৰ বিষয়ে অৱগত কৰাব। চাফা কৰা, পানী ভৰোৱা আদি কামো ই নিজেই কৰি ল’ব। যদিহে পৰিশোধন কৰিবলগীয়া পানী খিনিত বেছি পৰিমাণে লেতেৰা আৰু সংক্ৰামক দ্ৰব্য থাকে, তেনেহ’লে এক বিশেষ চেকনীৰ ব্যৱহাৰ কৰি সেইবোৰ আঁতৰাব পৰা যাব।”

বিপৰীত আসৃতি (আৰ ও) পদ্ধতিৰে কৰা পৰিশোধন প্ৰক্ৰিয়াত পানীত থকা উপকাৰী খনিজ সমূহও ওলাই যায়। প্ৰফেছৰ আলোক ধাৱানে জনোৱা মতে “অ’নীৰৰ এটা বৈশিষ্ট হৈছে যে ই পানীত থকা উপযোগী খনিজ সমূহ ধৰি ৰাখে। এইদৰে অ’নীৰৰ দ্বাৰা পৰিশোধিত পানী আমাৰ সুস্বাস্থ্য ৰক্ষাত সহায়ক হ’ব।”

অ’নীৰৰ এটা ব্যৱসায়িক প্ৰ’ট’টাইপ ইতিমধ্যে মুকলি কৰা হৈছে। ভাৰতীয় বিষবিজ্ঞান অনুসন্ধান সংস্থানৰ (আই টি আৰ) কৰ্মচাৰী সকলে নিয়মিতভাৱে অ’নীৰৰ দ্বাৰা পৰিশোধিত পানী ব্যৱহাৰ কৰি আছে। বৈজ্ঞানিক আৰু উদ্যোগিক অনুসন্ধান পৰিষদৰ (চি এচ আই আৰ) খেল ধেমালী সমূহত নিয়মীয়া ভাবে ব্যৱহাৰ হোৱাৰ উপৰিও অলপতে হৈ যোৱা কৃষি মেলা এখনত পাঁচ হাজাৰ লোকে এই পানী সেৱন কৰিছিল । গ্ৰাহকৰ মতা-মত জানিবৰ বাবে লক্ষ্ণৌ চহৰৰ বিভিন্ন  ঠাইত  পাঁচ- ছয়টা পৰীক্ষামূলক ফিল্টাৰ স্থাপন কৰাৰ প্ৰক্ৰিয়াও চলি আছে। ডঃ আলোক ধাৱানে জনোৱা মতে বাণিজ্যিকৰণৰ বাবে অ’নীৰ সম্পূৰ্ন  সাজু আৰু বিভিন্ন ব্যক্তিগত খণ্ডৰ প্ৰতিষ্ঠানে ইতিমধ্য়েই এই ফিল্টাৰটোৰ ব্যৱসায়িক উৎপাদনত আগ্ৰহ প্ৰকাশ কৰিছে।

Section: General, Science, Technology, Health, Deep-dive Source:
Bengaluru Monday, 24 September, 2018 - 21:38

200 scientists, 73 research institutions, 20 countries and 13 years—this is what it took to complete a task that was once deemed implausible. Yes, it is the herculean task of sequencing the genome of the bread wheat (Triticum aestivum)—a grain that is used every day to prepare rotis, parathas and everything in between. In a recent study spearheaded by the International Wheat Genome Sequencing Consortium (IWGSC), researchers have reported the completion of sequencing the entire wheat genome.

Genome sequencing is the method of finding out the order of nucleotides bases which forms the DNA-the fundamental unit of all life-forms. It is made up of four repeating unit- Adenine, Guanine, Thymine and Cytosine. Scientists and farmers can now use this valuable information produced from wheat genome to increase the productivity of the grain on the existing but ever-depleting cultivable land without hurting the biodiversity and environment and using limited water and nutrients.

Wheat is one of the most important food crops in the world and is the staple diet of more than a third of the world's population. Yet, its genome was not fully understood until recently. The first draft of the genome sequence was published in 2014, and four years later, we now have a full reference genome with a far-reaching impact on the scientific research, plant breeders and global population.

What is the complexity of this task, considering even the human genome is already sequenced, you ask? Well, it is the size and structure of the wheat genome! The wheat genome is huge—more than five times the human genome and 35 times that of rice! It has 21 chromosomes originating from three highly similar smaller-genomes (A, B, and D), each of which is larger than the human genome, and contains seven chromosomes. To those unaware, the human genome is 3.3 billion nucleotide base pairs, while the wheat genome is 16 billion nucleotide base pairs!

The highly repetitive elements of the wheat genome add to its complexity—more than 85% of the genome is made up of repeat elements, and only 2% represents genes. Repetitive elements, which are patterns of nucleic acids present in several copies, are characteristics of most genomes. Hence, assembling a genome as huge as wheat, using small sequences called as reads, derived from sequencing machines, is an uphill task. The closest analogy of reads and its assembly could be a jigsaw puzzle with many pieces that are similar in shape and size, making it harder to assemble into a meaningful picture.

The scientists in the consortium tried to solve the above problem by following the same approach used in sequencing the genomes of other organisms like the mouse, human or rice. They reduced the complexity of the genome by sequencing each chromosome separately, and the end product was a near-perfect genome that can be used by scientists and breeders. With 94% of the genome covered, it is by far the best reference genome of wheat available till date. The study presents the location of 107,891 genes (compare this with only 20,000 genes in humans) and more than 4 million genetic markers—fragments of DNA in specific places and necessary for particular traits. It also presents the regulatory elements that would control gene expression—all handy tools for future research on wheat. 

There was also a significant Indian contribution to this colossal effort, with 18 scientists from three institutes, led by Dr Kuldeep Singh from the Punjab Agricultural University, Ludhiana who is also the Director at ICAR-National Bureau of Plant Genetic Resources, Prof. Nagendra Singh at ICAR-National Research Centre on Plant Biotechnology, New Delhi, and Prof. JP Khurana from the University of Delhi. They were tasked with the sequencing of the 2A chromosome, which constitutes 5% of the wheat genome. The Department of Biotechnology, Government of India, supported the research on the Indian side.  

India, the second largest producer of wheat after China, with production crossing 98 million tons in 2017-2018, is poised to make the best use of the genome information. With its population marching towards 1.6 billion by 2050, and the world population set to rise to 9.6 billion, the productivity of wheat has to increase by 1.6% annually to feed this ever-growing demand, notes IWGSC. Tuning the right gene to do this holds the key.

In addition to food security, there is also a need for developing wheat varieties that can stand the test of the changing climate. Using the information of the genome sequencing, scientists can develop high-yielding varieties of wheat that also has better resistance to environmental stresses and pathogen attacks. If you are allergic to gluten, the study may be good news to you since allergies associated with wheat-derived gluten could be mitigated by targeting the genes that might contribute to it.

The scientists behind the research hope that wheat genome sequencing could open up several possibilities to breeders and farmers, as it did when maize and rice genome were sequenced in 2009 and 2005 respectively. Coupled with gene editing technologies like CRISPR-Cas9, this breakthrough could change the future of wheat research for better. Although the cloud of scepticism over genetically modified plants persists, the availability of a high-quality reference genome of wheat is indeed a first step forward towards addressing the global problem of food scarcity.

Section: General, Science, Society, News Source:
Hyderabad Sunday, 23 September, 2018 - 23:30

Mosquitoes are not only known for their pesky bites, but also as vectors for transmitting about 17% of all infectious diseases—dengue, malaria, chikungunya and the likes. The female mosquitoes devour the blood meal to meet their protein and iron needs to lay their eggs, eventually transmitting several diseases. One such severe problem caused by mosquitoes is lymphatic filariasis, also known as elephantiasis. In a recent study, researchers from the Indian Institute of Chemical Technology, Hyderabad, University of Nevada, USA, and University of Georgia, Athens, USA, have provided insights into potential of developing a novel insecticide to control mosquitoes and filarial parasites.

Lymphatic filariasis, considered as one of the neglected tropical diseases worldwide, is a parasitic disease affecting the lymph nodes. It causes swelling and thickening of the skin and leads to permanent disability. Though filariasis is caused by three species of nematode worms (filariae), Wuchereria bancrofti (Wb), transmitted by mosquito species belonging to the genera Culex, Anopheles, Aedes and Mansonia, affect humans the most.

According to the World Health Organization, 120 million people across 55 countries are infected by this disease. In India, Culex quinquefasciatus is the primary vector of Wb, approximately constituting 45% of the world’s lymphatic filariasis burden. Improper drug administration, insecticide resistance in mosquitoes and drug resistance in the parasite, are often blamed for the spread of the disease.

In the current study, the researchers have found a link between a biological mechanism involved in the glucose uptake in cells, insulin signaling, and the filarial worm development in the mosquito Culex quinquefasciatus. The study, published in the journal PLOS Neglected Tropical Diseases, has provided clues on how insulin signaling can be targeted for development of a mosquito-specific, safer, and effective insecticide against mosquitoes and filarial parasites.

Filarial worms multiply inside vertebrates and undergo a developmental stage within mosquitoes. The ability of mosquitoes to acquire and mobilize nutrients plays a crucial role in the development and transmission of these worms. Filarial parasites are taken up by the mosquito when the female mosquito feeds on an infected person. Filarial development within mosquitoes takes 10-12 days to complete, during this time the parasite moves from mosquito’s midgut (stomach) to flight muscles (where it grows to infective stage), and finally into head via hemolymph (mosquito’s blood). When mosquito takes another blood meal from an uninfected person, the filarial parasites comes out of mosquito’s head and make their way into the bloodstream through skin.

In mosquitoes, like most organisms, insulin receptors—proteins found on the surface of the cells, help them in the absorption of glucose through the conserved insulin signaling pathway. Like in humans, insulin-like peptides (mosquitoes’ insulin) binds to the receptor and help uptake of the nutrients by the cell. These nutrients regulate reproduction by providing the energy for the development and laying of eggs.

In the study, the researchers silenced the gene responsible for producing the insulin receptor protein in Culex quinquefasciatus mosquitoes. They then infected these mosquitoes with the filarial parasite, Wuchereria bancrofti, for understanding the role of insulin signalling in filarial worm development. They observed how the absence of the mosquito insulin signalling mechanism affected the development of the filarial worms and found that silencing insulin receptor of mosquitoes resulted in complete lack of developmental stages of the worm in mosquito body parts.

“This could be due to either the death of filarial worms at early larval stages before reaching thoracic muscles or failure to mature due to nutrient limitation,” says Dr Monika Gulia-Nuss, Assistant Professor in Biochemistry, University of Nevada, USA, and the lead author of the study.

Insulin receptors silencing also interfered with blood digestion in the gut of the mosquitoes, resulting in further decrease in nutrients from the blood. These mosquitoes also had reduced levels of ecdysteroid—an insect hormone involved in moulting and reproduction.

The researchers also observed a drop in the egg-laying capacity of the infected mosquitoes. While the uninfected mosquitoes deposited 92 eggs per female within 96 hours after ingesting human blood meal, the infected mosquitoes laid only 58 eggs (37% fewer). The insulin receptor silenced mosquitoes produced no egg production at all. This observation shows that silencing the insulin receptor and the prevalence of Wb infection decreases the egg-laying capacity of the mosquitoes.

In tropical countries like India, where the mosquito menace is a major public health issue, this research could help us understand some of the underlying biological mechanisms at play in the transmission of these diseases.

“This is a proof-of-concept study that strongly suggests a link between mosquito insulin signalling and pathogen development within the mosquito vector. In the future, we plan to study the insulin signalling mechanism in both filarial and malarial parasite development. We are also evaluating insulin receptor antagonists—small molecules that bind to the receptor—which could be used as a novel insecticide to block the transmission of parasites”, says Dr Gulia-Nuss, describing the future direction of this study. 

Section: General, Science, Health, Deep-dive Source:
Bengaluru Sunday, 23 September, 2018 - 11:44

The banks of the river Krishna, an iconic river in South India, is a sight to behold! As you gaze through its vastness, have you ever wondered how the river is, and since when it is flowing? Here is a trivia—the rivers that flow in Karnataka are, in fact, older than the mighty Himalayas!

Karnataka is bestowed with seven critical river systems that are lifelines to the state—Godavari, Krishna, Cauvery, North Pennar, South Pennar, Palar and all the west flowing rivers. The Cauvery is the largest river in the state and originates from Talakaveri in Madikeri district. Although many rivers flow to the west and join the Arabian Sea, they account for a meagre 12.73% of the water that drain in the state. The majority, a whopping 87.27% of the drainage area, is a result of the six mighty east-flowing rivers. Why this starking imbalance, you wonder? There is a bit of geological history to this, and the story starts with the history of the Western Ghats, where most of Karnataka’s rivers originate.

The chronicles of the Western Ghats

Over 180 million years ago (mya), all of the present-day land mass, the seven major continents as we know them, was merged into a supercontinent called the Gondwana land. Thanks to an extraordinary geological event, the massive landmass broke up into several pieces and one of them, the Peninsular Indian plate, drifted northwards for about 100 million years. About 45 mya, it eventually hit the Asian plate resulting in the formation of the Himalayan mountain range.

During this arduous journey, the drifting Peninsular Indian plate passed through the present-day Reunion Islands, which had a volcanic centre in the Earth’s lithosphere spread over 200-300 km. The volcano, which erupted throwing out basaltic magma, resulted in the uplift of what is now the Western Ghats and tilted the Indian plate in the easterly direction. Thus, the Western Ghats are not actual ‘mountains’ but faulted edge of a raised plateau.

By the time the Peninsular Indian plate ended its northward drift and collided with the Asian mainland (between 45 and 65 mya), the Western Ghats was already there with permanently cast the drainage patterns. Hence, although most rivers in Karnataka originate in the Western Ghats, they eventually drain into the Bay of Bengal.

Ecology and Biodiversity

With a distinguished history in their origins, it is little surprise that the rivers in the Western Ghats have nurtured a unique ecosystem. The Ghats have high-altitude grasslands, the shola montane forests, wet evergreen forests, semi-evergreen, moist deciduous and dry deciduous forests. As one moves eastwards towards the plains, a bulk of the plateau is scrub—grasslands with occasional dry deciduous forests. These unique landscapes are home to several species of plants (like the Neelakurinji which blooms once in 12 years) and animals (like the endangered Lion-tailed Macaque) which are found nowhere else on Earth.

The scrublands form the catchment area and are part of the river hydrology that is responsible for capturing the incident rainwater and draining them off. Most west flowing rivers are perennial, while the east-flowing rivers depend on the monsoon rains.

Supporting livelihoods

India, an agriculture-dominated country, has over 70% of its population directly or indirectly dependent on the rivers for food and livelihood. In Karnataka, the rivers originating in the forests of the Western Ghats provide food and power security for the entire southern Peninsular India. The east-flowing rivers, which flow for thousands of kilometres before joining the Bay of Bengal, support livelihoods of hundreds of towns and villages on their downstream journey. 

Massive irrigation projects on the rivers like Cauvery, Krishna, and the Godavari serve as the granary of the Deccan plateau. Apart from household consumption and irrigation, these rivers also provide water for the generation of electricity. The west-flowing rivers mostly contribute to the production of electricity to power Bengaluru's IT hub and other parts of Karnataka. The Karnataka Power Corporation Limited has 34 dams on its rivers and 24 hydropower stations across the state.

Fisheries also form a substantial means of livelihood for those who live on the banks of these rivers and their tributaries. The livelihood means of tribals and other local people also largely depends on these river systems.

Rivers for Development

Since the east-flowing rivers are vital sources of water for drinking and irrigation, large dams have been built in the past to cater to these needs. With the generation of hydroelectricity gaining momentum in the last century, several hydroelectric projects came up along the Western Ghats. A series of dams have been built along the Sharavathi, which has reduced the natural flow of the 140 km long river to a mere 8 km! The ecological impact of dams has been irreparable. For instance, several species of stream fishes are unable to move across the stream for breeding since they are now confined to one side of the dam. Some species, which swim upstream for reproduction, are now restricted.

The construction spree of these massive dams took a break in the 1970s after a protest by locals against building a dam across River Bedthi. However, in the past decade, there has been a resurgence of small dams instead of the large ones, including the controversial Yettinahole project taken up by the Government of Karnataka. 

The Yettinahole River Diversion Project

Two rivers, Kempuhole and Kumaradhara, originate in the Sakleshpur taluk of Hassan district and flow westwards through the Western Ghats and drain into the Arabian sea. A massive ongoing project aims to divert nearly 24 TMC of water from the headwaters of the Kempuhole river, a tributary of the Netravati, towards the water-scarce regions of Kolar, Ramanagara, parts of Hassan, Tumkur, Chikkaballapur, Bengaluru Rural, and Devanahalli Industrial area.

The project also plans to divert the west-flowing Yettinahole stream, which eventually joins Kempuhole, through eight diversion weirs/dams and a canal network spanning 1,000 kilometres. The water will be pumped from the weirs through giant pipes that cut across the Western Ghats to channel this water eastwards. Seven massive storage reservoirs are also planned to be constructed in other parts of the state. This project, estimated to cost about Rs 13,000 crore, is energy and resource intensive and is expected to hurt the biodiversity of the region.

The recent floods in Madikeri district and Kerala ring a warning bell for pursuing any alterations to the ecology of the Western Ghats and rivers in particular. Understanding the river hydrology and floodplains, which form diverse habitats for flora and fauna, can go a long way in arriving at sustainable solutions. Time and again, ecologists have raised concerns against river linking and the threats it can cause to larger ecosystems. It is crucial that policymakers apply an integrated river water management framework that is evolved at a watershed level. Development goals should be evolved locally, and the water demands should be assessed at watershed levels. Unfortunately, it looks like the developmental activities at Yettinahole is another disaster in the making.
 

Section: General, Science, Ecology, Featured Source:
Bengaluru Friday, 21 September, 2018 - 16:51

Scientists are always on the lookout for novel chemical compounds with medicinal properties to fight many of the diseases we know. In one such effort, researchers from the Aligarh Muslim University, Uttar Pradesh, and their collaborators have developed three compounds with steroids and pyrimidines with remarkable biological applications. The results of the study are published in the International Journal of Biological Macromolecules.

The novel chemicals compounds, called ‘steroidal pyrimidines’, were synthesised in a laboratory by combining the compound steroidal thiosemicarbazone, with another compound called (2-methyl) diethyl malonate. The researchers then explored how these compounds interact with the DNA molecule in our cell and also studied the anticancer potential of these compounds.

The study showed that all the three steroidal pyrimidines had a strong affinity for the DNA molecule. To get an insight into the interaction process, the researchers used molecular docking—a computer-based approach to predict the orientation of a molecule in a compound. Docking indicated that in spite of their large size, the steroidal pyrimidines interact with the minor groove—a shallow furrow in the DNA molecule.

Interestingly, one of the newly synthesised compounds has a unique ability to cleave into the DNA molecule—a task that is not easy considering the stability of the phosphodiester bonds linking the nucleotides in a DNA molecule. DNA cleaving agents are vital in molecular biology for uses like insertion of a human gene in a bacterial DNA or preparation of recombinant DNA. Although some metal compounds can cleave the DNA, they are not preferred because of their toxicity.

When the researchers experimented the use of the steroidal pyrimidines with human cancer cells, they observed that the compounds have anticancer potential and one of these compounds was able to kill the cancer cells by inducing apoptosis—a tightly controlled cell suicide process. This compound, the researchers predict, has an excellent prospect to act as a cancer chemotherapeutic candidate in the future.

“The present study has shown that these synthesised steroidal pyrimidines can be used as a template for future modifications to design more potent and selective cell killing and DNA binding agents”, remark the authors on the potential applications of the compounds.

 

Section: General, Science, Health Source:
Mumbai Thursday, 20 September, 2018 - 22:52

Excess of arsenic in drinking water leads to arsenic poisoning which is linked to cancer, cardiovascular diseases and diabetes in adults and cognitive impairments in unborn babies. Now, researchers from the Indian Institute of Technology Bombay (IIT Bombay) have developed a filter that can reduce arsenic content in drinking water to acceptable levels.

In India, close to 24 crore people living in 21 states have been drinking water containing high levels of arsenic. Among them, the majority live in the Gangetic and Brahmaputra plains, where untreated water from tube wells have notorious levels of this cancer-causing chemical. Developed countries and big cities have a centralised water treatment system to purify water, including arsenic removal. In rural areas of India, settlements are smaller and spread out, and a central water treatment facility is not feasible. On the other hand, decentralised units to purify water are also not useful because they are expensive, inefficient and need skilled labour to operate.

The new arsenic filter, developed by Prof Sanjeev Chaudhari and his team from the Centre for Environmental Science and Engineering at IIT Bombay, can be attached to existing community handpumps, commonly found across India. The filter uses an elemental form of iron present in iron nails to remove arsenic through a chemical reaction between iron, arsenic, and oxygen. The filtering process involves no harmful chemicals and uses up to 20 times lesser amount of iron as compared to other similar techniques.

The researchers claim that the newly developed filters can provide safe drinking water to around 200 families in a village every day and reduce the amount of arsenic by 100 times—sufficient to comply with the recommended international standards. The design of the filter is flexible and can be modified to fit larger filter systems. The arsenic-contaminated waste collected can remain in the filters for about five years without any leak, thus making it safe. They need to be cleaned only once in three months and do not require constant supervision and hence are easy to maintain.

The filters can also be built by local communities, thus saving a considerable cost. “In West Bengal, two local boys were involved in building the filter system, and the local masons and plumbers did the job of installation", says Prof Sanjeev Chaudhari, citing an example. "In Ballia and surrounding areas, one local person, assisted by local masons and plumbers, could do the job”, he adds.

The filter unit needs to be connected to the existing handpumps prevalent in the rural communities by attaching a lift and force unit or by modifying the India Mark II pumps. The filter unit consists of two tanks. Each tank has two sections—one with iron nails and another with stone aggregates. The iron nails convert arsenic into a removable form in the presence of dissolved oxygen present in water and hold on to it.  The stone aggregates filter the water and remove other suspended impurities. The two tanks act as a fail-safe mechanism where one still filters the water in case the other fails.

Talking about the cost of installing the new filters, the researchers say that for a community of about 100-200 households, the installation cost ranges from ₹40,000 to ₹75,000 based on the region as the material and transport costs vary. Also, the annual maintenance cost to clean the filter comes up to around ₹1000. Hence, the effective running cost of obtaining arsenic-free water works out to be less than a rupee a month for a family of five!  

The researchers first installed arsenic removal filters as a trial in four villages in West Bengal in 2008. On tasting success, they further installed, 60 such filters in the Gangetic plains—27 in Uttar Pradesh, 21 in Bihar, 4 in Assam and 8 in West Bengal. Over time, they have improved the design of the filters to suit the rural masses based on the feedback received from the villagers. 

One of the challenges faced in the installation and use of the arsenic filters in the villages is the lack of awareness about such water treatment technologies, say the researchers. The government needs to make efforts to promote such filters in the rural areas. There may be some reluctance too because previous treatment facilities were either too complicated for the villagers to operate, or, in some cases, were very expensive. Although the new filters address these concerns, there are a few technical challenges in the village infrastructure, like the quality of handpumps. “Our arsenic filter seems to be quite robust in delivering good quality water, but the hand pumps have frequent breakdowns due to excessive use, and the filter ends up not being used”, points out Prof Chaudhari.

Another challenge that the researchers point out is that the lack of awareness also affects the maintenance of the filter and the handpump. “Since the arsenic filter was initially provided free of cost, the villagers later did not want to pay for the maintenance of handpump too,” says Prof. Chaudhari. “Wherever people are slightly aware, our arsenic filters are still operational. Hence, the success of the technology will depend on the awareness level and the ability to pay,” he signs off. 

Section: General, Science, Technology, Engineering, Health, Deep-dive Source:
Chennai Thursday, 20 September, 2018 - 13:31

Do you frown upon the smell of garlic? Perhaps it’s time to ‘age’ it and use it as it may help you protect your liver. In a recent study, researchers from the Chettinad Academy of Research and Education, Chennai, Indian Institute of Technology Madras, and the University of Kalyani, West Bengal, have studied how aged garlic extract can help fight cancer and repair damaged liver. The results of the study were published in the journal Drug and Chemical Toxicology.

Garlic, or Allium sativum, has historically been a part of many cuisines around the world. Its medicinal uses are documented in many traditional systems of medicine. However, thanks to the sulphur-based compound called allicin, the unpleasant odour of raw garlic puts off many from eating it. Aged garlic extract can provide all the goodness of garlic minus the smell. It is produced by storing fresh garlic in ethanol for a long time, sometimes up to months. This process of ageing retains all the useful compounds found in raw garlic but not allicin.

The researchers of the current study used rats in their experiment to study the beneficial effects of aged garlic. They first treated the rats with two cancer-causing agents, p-dimethylaminoazobenzene and phenobarbital, which harmed the liver of the rats. When the rats showed signs of liver damage, they were treated with aged garlic extract daily to observe how it helps to repair the damage. 

Toxicity in a liver leads to accumulation of products like serum triglyceride, creatinine, urea, and blood urea nitrogen. The experiments by the researchers showed that aged garlic extract was able to reduce the above compounds, establishing the fact that the treatment was beneficial for the rats. The garlic extract also protected the liver by balancing the amount of blood glucose, HDL-cholesterol, albumin, and haemoglobin in the liver.

Besides the aged garlic extract, the researchers also studied the efficacy of a commercially available aged garlic extract called kyolic. It is prepared from organically grown garlic with an ageing process of up to 20 months. The kyolic extract showed the ability to control the growth of the liver cancer cells.

Although the beneficial properties of garlic and its extracts were known, this study presents a systematic assessment of the beneficial effects of generic aged garlic extract and the specific kyolic garlic extract. “Our study validates the use of aged garlic extract in the treatment of diseases causing liver toxicity including liver cancer”, say the researchers explaining the potential applications of their findings.

Section: General, Science, Health, News Source:
Bengaluru Thursday, 20 September, 2018 - 00:37

Ever wondered what’s common among whipped cream, mayonnaise, butter, ink, coloured glass and paints? It’s the fact that all these substances are ‘colloids’—a mixture in which microscopic, insoluble particles of one material is dispersed into another. Scientists study colloids to understand how the dispersed particles behave and to decipher phenomena like crystallisation and phase transition. Colloidal suspensions have different viscoelastic (viscosity+elastic) properties, owing to the interparticle interactions and their structure. Hence, understanding the stress-strain relationship and flow behaviour of these particles are gaining momentum. 

Interestingly, the interparticle interactions can be changed or controlled by an external stimulus. Adding salt or applying electric or magnetic field can produce different structural organisation in the colloids and alter the flow property of the particles. In a recent study, researchers at the Raman Research Institute (RRI), Bengaluru, have shown what happens when an electric field is applied to Laponite nanoclay colloidal suspensions. The results are published in the journal Soft Matter.

Laponite is a synthetic clay which swells to produce a clear, colourless suspension when dispersed in water. In this study, the researchers have shown that when an electric field is applied, it can form soft, gel-like solids. The structure and the elastic nature of the soft solid can be altered by changing the electric field.

“The motivation of our work was to understand how the rheology (study of the deformation and flow of matter) of this particular colloidal suspension can be systematically altered by applying an external drive like an electric field, while simultaneously correlating the material structure to the observed rheology”, says Dr.Ranjini Bandyopadhyay, Professor at RRI and an author of the study.

The structure of Laponite particles resembles a disc and has a non-uniform charge distribution. Sodium ions from Laponite particles get dissociated when dispersed in water and form a diffuse layer of positive charges around the negatively charged Laponite discs, thus forming an electric double layer. When dispersed in water, the faces of the disc bear negative charges and the rim bears weak positive charges. The predominantly negatively charged particles repel each other and form a stable suspension.

In the current work, the researchers applied an electric field of strength varying between 2.5 kVm-1 and 10 kVm-1 to the Laponite suspension for 15 minutes. They observed that in each case, a soft solid was obtained, which under analysis showed a gradual increase in elastic nature and a corresponding change in the microstructure.

The researchers further noticed that under the influence of the electric field, the characteristics of the charged double layer around the Laponite particles change. The individual Laponite particles sense the external field and move towards the positive electrode, where particles interact with the electric field and with each other, rapidly forming clusters and attaining a soft gel-like structure. 

Another remarkable observation was the changes in the structure of these colloidal particles under an electron microscope. The researchers saw that the soft solid, formed when a higher electric field strength was applied, had percolated network structure. The particles were found to be arranged in ‘house-of-cards’ and ‘overlapping coin’ structures. In a ‘house-of-cards’ arrangement, the face of one particle touches the rim of another particle, and the same stacking pattern continues. In an 'overlapping coin' arrangement, the particles stack on top of another like a jumbled pile of coins. In contrast, the soft solids obtained at a lower electric field strength had a more open structure, where there was less interconnect among the chains of particles.

The study identified that the soft solid formed with higher electric field exhibits a higher storage modulus—a measurement indicating that the material behaves like an elastic solid. This property is due to the networked microstructure of the soft solid. “Our gels are also stronger and more stable than, say, Laponite gels obtained by adding salt”, remarks Dr.Ranjini

When the researchers subjected the soft solids to stress test, they found them to be very fragile and required a minimal pressure to break. This fragility could be because these gel-like solids form rapidly, without structurally organising into an optimal configuration, say the researchers. Interestingly, they found that the soft solids formed at a higher electric field deformed in two steps—first, the cluster network made by chains of particles broke, and then the chains made by individual particles crumbled.

The research illustrates how the rheological property of the Laponite colloidal suspension can be modified by merely varying the strength of the external stimulus. As a next step, the researchers will attempt to form a reversible Laponite soft solid. “To use these materials as ‘smart systems’ needs more work. I guess that looking into the potential reversibility of this transition would be a good start”, says Dr.Ranjini before signing off.

Section: General, Science, Technology, Deep-dive Source:

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