Have you ever been away from the city, away from the bustling activities and clattering? If you have, then, without all the noises of the city to distract you, you might have noticed how loud a seemingly empty field is! Birds, frogs and insects all join in on this chorus. The animals making these calls need to invest time and energy into making them, and hence are made for specific reasons, where every call counts. Often, in the animal kingdom these vocalisations are used to attract potential mating partners. To be heard by a female frog, the male of the species must not only compete with other members of the same species, but also ensure that his song stands out in the surrounding uproar. How an individual of one species positions itself, changes the timing or the nature of its call are all factors that have been studied by scientists. In a recent study from the Indian Institute of Science, Bangalore researchers have explored how the timing of the calls of two species of tree cricket has ensured their reproductive isolation. Studying the tree crickets Oecanthus henryi and Oecanthus indicus, the researchers used a statistical model to study how an individual respond to calls made in its surroundings. Their findings from the field showed that individuals belonging to the same species responded more strongly to call of their own species than the statistical model predicted. Similarly, individuals belonging to different species responded poorly to the call of the other species than predicted by the model. This research indicates the crucial role acoustic signals play in the reproductive isolation species in the wild. It also shows that animals may be better at recognizing members of their own species, than we predicted.
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Medical advancements and modern scientific techniques strive to solve challenges posed to human communities, especially healthcare threats. Viruses are one of the major threats and tend to make themselves resistant to drugs and evolve new mechanisms for survival by making subtle changes in their DNA called as mutations. Today among the many viruses, Dengue virus has been a serious problem causing mortality in widespread areas. Although treatments and drugs have been developed, it is essential to make sure that we’re ready to face worse cases in future. Every family of organisms have a common DNA sequence conserved through the course of evolution, called as consensus sequences. A strategy to detect the consensus sequence of dengue virus has been attempted in a new study by researchers from Amity University, Noida and Maharishi Dayanand University, Rohtak , so that we will be able to identify even if the virus disguise themselves with DNA mutations. The researchers have introduced a new sensor to detect Dengue virus using the new technique
A DNA molecule has two strands complementary to each other, like a zipper. Probe DNA (pDNA), a single-stranded DNA sequence complementary to the consensus sequence of dengue virus was synthesized in the new study. pDNA has a tendency to bind to a target DNA (tDNA) (i.e. dengue viral DNA) when brought in proximity. The researchers used Methylene blue (MB), which serves as an indicator of pDNA-tDNA interaction by emanating electrical signals. It was also found to react differently with pDNA and pDNA-tDNA hybrid. Normally, MB binds with pDNA giving out increased response but the signal intensity decreases after the interaction as it is sandwiched between two strands of DNA. Thus, following the electrical activity reveals the dengue contamination in patient samples. The support material has been studied thoroughly by various techniques and optimal concentration of pDNA that can be loaded onto them for best signal detection has also been determined. This technique surpasses the disadvantages faced by the previous sensors, such as cross reactivity and specificity towards a particular serotype. The new sensor can be used for fast detection of dengue in suspected patients by placing it in the samples and recording the electrical activity.
The human body has a mechanism to maintain a certain balanced pH (potential of Hydrogen), or the degree of acidity or alkalinity in the body. Generally, this is found to be around 7.35 (on a scale of 0-14), and it varies throughout the day, depending on one’s diet and activities. The pH levels in tissues are far more sensitive. A slight decrease in the pH, that is a slight increase in acidity in tissues, is called Tissue Acidosis; the degree of acidosis is relies on the circulating glucose concentrations, and conditions like Hyperglycemia or increased blood sugar level causes higher degree of acidosis.
It is well known that tissue acidosis, along with high lactate concentrations, are associated with cerebral ischemia--an unfamiliar word in the household context. Ischemia is the condition where there is a shortage of blood supply to a certain parts of the body. There are various types of ischemia, and the one concerning the braincerebrum is ‘Cerebral ischemia’.
Along with a number of other agents, lactates and protons have been found to activate the potassium channel TREK1 and its increased activity has shown to hinder ischemic cell damage. hTREK1 is an intracellular ionic channel through which potassium ions travel in and out of the cell. In a new study by the Molecular Biophysics Unit, Indian Institute of Science, Bangalore, it was observed that a certain concentration of lactate(30 mM) at pH 7.0 and 6.5, levels which are generally seen during ischemia, can cause booming increase in the effect of hTREK1 activity. While the same concentration of lactate at pH 6.0 and 5.5, observed during hyperglycemic ischemia, reduces the activity of hTREK1 significantly. The effects of 30 mM lactate concentrations ̶ also known as ischemic concentration ̶ is very specific and when experiments were conducted with 3 mM lactate and 30 mM pyruvate at pH 7.0 and 5.5, it failed to show similar results as that of lactate (30 mM).
Since hTREK1 is a gene which can be experimented upon, it was further subjected to deletion and mutation. From this, it was inferred that lactate changes the pH modulation of hTREK1 by behaving differently with Histidine, which is an amino acid residue. This is the first time that such varying effect of pH-dependent lactate on the normal functioning of an ion channel has been reported. This plays an important role in recognizing and addressing different stages of ischemia.
In July this year, the Moderate Resolution Imaging Spectroradiometer on NASA’s Aqua satellite photographed a major chunk of glacial ice shelf (5,800 sq. km) breaking off from one of Antarctica’s floating ice platforms, called Larsen C, shrinking its size by at least 10 percent. Melting glaciers is perhaps the most tangible reality of climate change, more so in the Himalayan region, since the gradual melting of Himalayan glaciers and snowfields supply freshwater to populations in India, Nepal, Bangladesh and Pakistan. Which is why monitoring the speed of deglaciation is more significant than ever,since it helps researchers to understand the implications they may have on populations depending on the meltwater. But are there more factors other than the climate contributing to the retreat of glaciers? A group of researchers from M.G. Science Institute, Ahmedabad; Space Applications Centre, ISRO, Ahmedabad; Indian Institute of Science, Bangalore and Department of Hydrology & Water Resources University of Arizona, Tucson, studied the Himalayan glaciers in the Chenab basin to understand the contributing factors to glacier retreat. They considered glacio-morphological factors such as aspect, length, area of the glaciers and area of debris cover, and altitude of snowline at the end of ablation. While 324 glaciers studied between 1962-2001/02 showed a 11% loss in glacial area, 238 of them observed between 2001/02 and 2010/11 showed only a loss of 1.1%. Less glacial shrinkage has been observed in longer glaciers with a larger area, than in the smaller ones. The study also found that glaciers in lower altitudes are prone to faster retreat than higher altitude ones. Debris covered glaciers were found to be least likely to melt, compared to debris free glaciers. Of the 158 glaciers found to have no debris cover, a 14% loss of area has been observed. Whereas glaciers with 40% debris cover were found to have retreated only to the tune of 8%. Another factor found to have significant effect on glacier retreat is the equilibrium line altitude (ELA). Between 2001/02–2010/11, glaciers below ELA showed 4.6% of deglaciation while ones above ELA experienced only 1.1%. Thus, factors like altitude, debris cover and ELA are found to be significant influencers in accelerating the retreat among glaciers in Chenab basin. While the effects of climate change on the glaciers are widely studied, this study provides a clue to other factors affecting them, and could be used to protect the disappearing glaciers.
Come summer, and we all struggle with availability of fresh and safe water. Have you ever wondered what can be done to conserve enough water when it rains, so that we don’t have to suffer from water scarcity in the summers? India is the largest groundwater user with unchecked groundwater consumption by farmers, industries, urban and rural citizens alike. While the country supports 18% of the world’s population, it has only around 4% of the freshwater resources. The semi-arid Aravalli hills region is experiencing rapid and unchecked urbanization due to the pressures of the growing National Capital Region (NCR) of Delhi. Increased water consumption as well as encroachment of water bodies and natural flow channels in the region have severely impacted the groundwater as well as surface water.
One of the biggest challenges in watershed conservation is the lack of data for planning interventions. Scientists from Indian Agricultural Research Institute, New Delhi and Satyabhama University, Chennai have developed a methodology to calculate run offs of ungauged watersheds using Remote Sensing imagery and Geographical Information Systems for Manesar watershed around Gurgaon. Among the methodologies available for the estimation of the surface run-off, the USDA SCS-CN (Soil Conservation System-Curve Number Method, approved by the US Department of Agriculture) and GIS-based methods are the most widely used.
The new methodology combined the USDA SCS-CN and RS-GIS methods. It involved the integration of land use-land cover maps with the Hydrology Soil Group maps, and the study of 14 year rainfall data (2002-15) to calculate the surface run-off coefficient. The hydrological behaviour of the watershed was then modelled using GIS and SCS-CN method. The study established the average annual surface runoff in the region to be approximately 0.21 m with an annual runoff coefficient of 0.29, based on an annual rainfall of 720 mm.
This methodology would be hugely useful for identifying surface run-offs for similar dry areas without gauges, where there is an urgent need to monitor and plan for watershed management and conservation measures. The data obtained would act as an important input for land use planning and watershed conservation policy in the country.
Approximately 75% of the emerging infectious diseases and 60% of all human diseases are zoonotic in nature, i.e. they are are caused due to the spread of infection between animals and humans. Leptospirosis, a zoonotic disease is a bacterial infection caused by the pathogen spirochetes and reports an estimated 1.03 million cases and 58,900 deaths each year. Leptospira contains 250 antigenically diverse species and due to these distinct variations in the bacteria --called serovars, creating a cross-protective vaccine against the disease is challenging. Natural immunity against a particular strain of Leptospira doesn’t necessarily ensure a mutual protection against the other serovars of the disease. Given the severity of the cases which occur it is often a misdiagnosed and under-explored disease.
The Regional Medical Research Center and Bharathidasan University conducted a study in three Primary Health Care (PHC) centers of South Andaman district where Leptospirosis has been an important public health issue since 1988. The study aimed at assessing the long-term clinical course and the level and duration of antibody persistence against various strains of Leptospira through natural infection. Patients reporting common symptoms of Leptospirosis were tested through a positive blood culture and sero-diagnosis (diagnosis conducted on blood serum) was conducted through the microscopic- agglutination test (MAT) to confirm the presence of the disease. In order to understand the level and duration of antibody persistence across diverse serovars, blood samples were collected from a sub-sample of positively tested patients at the time of reporting of symptoms and during convalescence at 2-3 weeks post diagnosis. In addition, blood samples were collected at various intervals between the duration of 1-48 months and were also subjected to MAT and blood culture tests to understand the long term clinical course of the disease. The results of this study could yield critical information with regard to the pathology and course of the disease post a natural infection. It could also help us understand the possibility of cross-protection amongst certain serovars in an endemic population leading to the creation of an effective vaccine to combat this epidemic disease.
In the present time, with increasing demand for transportation fuels coupled with declining reserves of crude oil, scientific communities are forced to focus on renewable fuels. Although biofuels obtained from energy crops such as food and non-food energy crops act as renewable fuels, various issues such as food versus fuel debate, biodiversity loss and their effect on the land has shifted the idea of energy production towards other alternative biofuel producers like waste materials and microorganisms. Using these alternative energy resources are also debatable, due to their inability to satisfy the demand for petroleum-based fuels and due to the relatively high production cost and slower rate of production of the biodiesel. In order to overcome the cost related to biodiesel production, researchers from IIT Roorkee, for the first time, have investigated the use of crude glycerol (CG), for heterotrophic cultivation of a of microalgae (namely Chorella sp.) in a Photo Bioreactor (PBR) to enhance biodiesel production. In heterotrophic cultivation system, a light source is not provided to the cells and the balance between oxygen and carbon dioxide is automatically adjusted with PBR. The study found that the quantity of biodiesel obtained was nearly two times more (446.50 ± 1.50mg L-1 day-1 ) than that produced from other methods. On evaluation, the quality of biodiesel produced was found to be of automotive quality which would ensure smooth running of an engine, improve cold start behaviour , reduced white smoke and ensure a longer shelf life, making it it is perfectly suitable for vehicular use. The researchers suggested that by recycling of CG for cultivation of micro algae, enhanced quality and quantity of biodiesel can be produced at a low cost. The study has contributed to sustainable and low cost production process of biodiesels, and on implementation, could help satisfy the high demand for transportation fuels in the present time by overcoming the relatively high production cost of biofuels.
Welding is a process that has been used to sculpt metal from the renaissance periods. Over the ages, it has become one of the key processes in making several consumable and artistic materials. Though there is mechanization in most industries, this field still has over 5 million people working in it. The massive industry, comes with its own set occupational hazards. Welding releases a cocktail of toxic gases, heavy metals and nanoparticles. Even upon exercising great care and protection, these substances can still be inhaled by the workers. Moreover, most welders do not use proper gear, hence inhale several of the aforementioned chemicals.
A recent study conducted using rats as model organisms showed a direct correlation between inhalation of stainless steel welding fumes and its negative impact. Chromium (Cr) is seen in very high concentrations in the lung tissue of the mice exposed to these fumes. It exists in two oxidation states – Cr(VI) and Cr (III) of which Cr(VI) is soluble and passes through the cell membrane, deeming it more toxic than the insoluble Cr(III) ions.
Cr(VI) interacts with DNA directly or indirectly through the formation of reactive oxygen species(ROS) causing oxidative stress via breaks in the DNA strands. This puts cells in a precarious state where they need to rescue their DNA from further damage, failure to do which , would result in cell death. Cells minimize the damage using antioxidants and DNA repair systems that arrest the cell cycle to counter the effect and minimize DNA damage, including via the NFĸB (a protein that helps in sensing cellular stress) and Nrf-2 (a protein that activates the production of antioxidant proteins) systems. However, if the damage is beyond repair, cells elaborately plan their death in a process called apoptosis. Apoptosis of cells was observed in the rats, showing the extent to which the fumes have caused damage.
The bottom line is, our cells have many repair systems in place to deal with DNA damage that could arise on exposure to various substances, one of them being Cr (VI). However, when push comes to shove and the damage reaches the point of no return, some cells sacrifice their lives for the greater good. Unfortunately, we do not yet know if our cells have a strategy to combat the chronic exposure that thousands of welders face on a daily basis.
Ever wondered if natural surroundings give out subtle hints before going through landscape level transformations? Scientists from Princeton University (USA) and Indian Institute of Science (India), have collaborated to try and figure out if there are any such hints or signs in nature, which can help in predicting transformations within grassland and woodland habitats in Serengeti-Mara. The researchers were working on ‘Critical Slowing Down’ (CSD), a phenomenon where as ecosystems approach natural landscape-level changes (regime shifts), they tend to become slow to recover from external disturbances in nature (also called perturbations). A few common examples of such perturbations are earthquakes, floods, storms, forest fires and even human-induced alteration of forests, wetlands and other natural landscapes. The researchers used ‘rainfall’ as a potential indicator, that brings about changes among grassland-woodland landscapes. With the help of information retrieved from satellite imagery and by using advanced statistical modelling, they have come close to predicting these transformations before they occur. ‘CSD effect’ has been tested and proven in laboratory settings as well as in well-mixed landscape systems. But this is the first time scientists are trying to study its effect on a large landscape-level scale. The study was also able to detect ‘sensitive regions’ within the grassland-woodland habitat which are more prone to regime shifts. The researchers further suggested that more such landscape-level experiments on the ‘CSD effect’ are needed, to prove it as a robust technique in identifying early signs of changes within large ecosystems.
Research at the Indian Institute of Science, Bengaluru and Vikram Sarabhai Space Centre, Thiruvananthapuram indicates that black carbon (BC) aerosol emissions from aircrafts could be impacting the stratospheric ozone layer. Aerosols are minute particles suspended in the atmosphere that interact with incoming and terrestrial radiation affecting the earth’s climate. Some aerosols, such as sulphates and, nitrates cool the atmosphere. BC, on the other hand, is a positive climate forcing agent, absorbing radiation across a wide range of wavelengths. Near the earth’s surface, BC concentration is known to disturb large scale atmospheric phenomena such as the Asian monsoon, and melt the Himalayan glaciers. By heating the lower atmosphere, it can also set off a convection system lifting the BC across the tropopause. Hence, it is important to understand the vertical distribution of BC under strong convection, such as over India during the monsoons. Lidar based studies have shown a near steady vertical distribution up to a height of 3 km. Recently, for the first time in India, hydrogen balloons were sent up into the atmosphere, over Hyderabad, to study the impacts of elevated BC concentration layers. Their in-situ measurements revealed sharp confined layers of BC at high altitudes of 4.5 km and 8 km over the Indian region. In the current study, researchers revisited these high-altitude balloon measurements to investigate possible causes for the presence of confined BC layers using a regional chemistry transport model. The model simulated vertical profile matched with the balloon measurements at lower altitudes of 3 km, but failed to capture the sharp confined BC peaks at high altitudes. This led the team to look for other sources of local BC injection at mid and upper troposphere, such as air traffic emissions. When incorporated into the model, it showed sharp BC layers in the vertical profiles akin to the observed BC profiles, indicating a causal role. The team also found noticeable levels of aerosols in the stratosphere using CALIPSO Lidar data over India. With an average residence time of 1 year, stratospheric BC aerosol pose a serious concern to the ozone layer and the new study is a step in the right direction.