- Rohini Subrahmanyam
 

Adult Russell’s viper (Photo: Kartik Sunagar)

Snake venom has evolved into a complex cocktail of chemical killers, with remarkable diversity across different snake species. Even the same snake species can face different evolutionary and ecological pressures over time, which can change the potency of its venom.

In a recent study published in BMC Biology, Kartik Sunagar, Associate Professor at the Evolutionary Venomics Lab, Center for Ecological Sciences, IISc, and collaborators explored how the evolutionary ecology of two snake species shapes their venom as they age. The team focused on two clinically relevant venomous snakes in India, the Russell’s viper (Daboia russelii) and the spectacled cobra (Naja naja) – both responsible for a distressing number of deaths and disabilities.

The researchers maintained more than 200 snakes of the two species in captivity, to source venom from them at different stages of the snakes’ lives. They then performed several experiments to check how the composition, activity, and toxicity of the venom changes over time as these snakes change their diet from feeding on one prey to another.

Russell’s viper neonate (Photo: Kartik Sunagar)

Interestingly, the toxicity of the two snakes’ venom varied based on its ontogeny – at which stage of life it was sourced from. In the Russell’s viper, newborns had considerably higher toxicity against mammals and reptiles, as compared to juveniles and adult snakes. On the other hand, the toxicity levels of the cobra venom remained the same over the course of its development. The latter could, however, bind strongly to receptors found in the cell surface of various prey animals, most likely to make up for its lack of ontogenic variation, the researchers suggest. The results provide a glimpse into the evolutionary arms race between prey and predator, and how snakes have adapted and developed effective venom concoctions.

The findings of the study can not only help us better understand how snake venom diversity may have evolved, but also aid us in developing more effective snakebite treatments, which is also a major theme of the lab.

REFERENCE:
Senji Laxme RR, Khochare S, Bhatia S, Martin G, Sunagar K, From birth to bite: the evolutionary ecology of India's medically most important snake venoms, BMC Biology (2024).

 https://doi.org/10.1186/s12915-024-01960-8

LAB WEBSITE:
https://www.venomicslab.com/

A photon is a small energy packet of electromagnetic radiation. The amount of energy carried by a single photon around the optical fiber communication wavelength (~1,550 nm) is extremely tiny – on the order of 10^-19 Joule – making reliable detection of individual photons highly challenging. Nevertheless, Single Photon Detectors (SPDs) play a crucial role in spectroscopy, astronomy, bioimaging, and sensing applications. SPDs are also integral parts of emerging quantum technologies, such as quantum computation and quantum communication. Photonic qubit is a promising platform for realising these quantum applications as they provide several advantages, such as room-temperature operation, long-range transmission, low de-coherence, and ease of manipulation. 

SPDs that operate at room temperature are of particular interest as one can avoid the energy and cost overhead introduced by cryogenic cooling. Although silicon-based single photon avalanche diodes (SPADs) are well-matured and operate at room temperature, these devices cannot operate at the telecommunication wavelength (1,550 nm) and beyond. This is due to the relatively higher bandgap of silicon than the energy of the photon, which forbids absorption. InGaAs-based SPADs, on the other hand, are sensitive to 1,550 nm photons, but suffer from relatively lower efficiency, high dark count rate, after-pulsing probability, and pose hazards to the environment. 

REFERENCE:

Abraham N, Watanabe K, Taniguchi T, Majumdar K, Room Temperature Single Photon Detection at 1550 nm using van der Waals Heterojunction, Advanced Functional Materials (2024).

https://onlinelibrary.wiley.com/doi/10.1002/adfm.202406510

LAB WEBSITE:

https://ece.iisc.ac.in/~kausikm/

Colours are one of the most striking ways in which Nature showcases her beauty. Be it the vividly-patterned wings of the butterfly, the elegant feathers of the peacock or the myriad-coloured birds—they all enthral, mesmerize and charm each of us alike—from a child to an adult, a layman to a scientist, a writer to a poet.

However, unlike the colours due to dyes and pigments, most of the colours observed in living organisms are primarily due to underlying periodic structures. Nature remarkably self-assembles these structures from individual building blocks that could be as small as a millionth of a millimetre. Apart from their aesthetic appeal, realization of these structural colours has tremendous applications in our everyday life. Structural colours can have a significant impact on modern electronic gadgets such as smartphones and laptops. The display panel of the devices based on structural colours will use the ambient light itself to power themselves, which in turn can also solve the problems of poor visibility of screens in excess glare.

Over the last decades, scientists across the world are striving hard to realize structural colours in laboratory that can mimic the beautiful colours seen in nature. However, the major impediments in realizing them have been the low mobility of the building blocks, namely colloids and nanoparticles, on surfaces. Owing to their large size, these particles do not diffuse significant distances on the surfaces before meeting another one of their kind, so that they would grow further on. For any useful application, tuning of this separation between the growing centres is very crucial.

In a major breakthrough, scientists at the city’s Jawaharlal Nehru Centre for Advanced Scientific Research and Indian Institute of Science have developed a new strategy wherein they can precisely control the spacing between these growing centres. They have taken recourse to soft-lithography to engineer surfaces with inhomogeneous yet periodic structures. With great ingenuity, they have been able to introduce attraction between the building blocks and the engineered surfaces that locomote the building blocks to the desired sites before the ensuing growth could begin. This technique gives a facile control over the growing structures and that too with much-needed simplicity in the growth techniques. These findings that will shortly appear in prestigious scientific journal “Proceedings of National Academy of Sciences, U.S.A. (2016)” are expected to have a crucial impact on the photonics industry.

Chandan K. Mishra, A. K. Sood and Rajesh Ganapathy, _Site-Specific Colloidal Crystal Nucleation by Template-enhanced Particle Transport_, Proceedings of National Academy of Sciences (PNAS), U.S.A. vol 113 (43), 12094 (2016)”.

http://www.thehindu.com/sci-tech/science/Bengaluru-researchers-mimic-nature-to-produce-richer-colour/article16896281.ece

Other Featured research

The role of variability in motor learning

BioSystems Science and Engineering (BSSE)  student, Mr. Puneet Singh, under the supervision of Prof. Aditya Murthy and Prof. Ashitava Ghosal, explored whether motor variability–often unwanted characteristic of motor performance–has any significance in motor learning. They proposed that motor variability has two components, one caused by redundancy and other due to random noise. In this work, Singh et al. quantified redundancy space and investigated its significance and effect on motor learning. They proposed that a larger redundancy space leads to faster learning across subjects and that noise is not the redundant component of motor variability. They also tested this hypothesis in neurologically diseased conditions to get a mechanistic understanding of how reward-based learning and error-based learning interact and how such learning is affected by redundancy space.
Publication: *P. Singh, S. Jana, A. Ghosal, A. Murthy* “Exploration of joint redundancy but not task space variability facilitates supervised motor learning”, PNAS, 2016 DOI: 10.1073/pnas.1613383113 <http://www.dx.doi.org/10.1073/pnas.1613383113>

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IISc Research Insignia
This page features the IISc logo or the abbreviation “IISc” used to exemplify an algorithm, a concept, a discovery, a design, an invention, a process, or any other scientific, engineering, or technological research done in IISc.

Landscaping IISc Logo

IISc logo landscape with iso-contours
The IISc logo landscape was created by computing a topology-based segmentation of a signed distance field. The figures below illustrates the different steps in creating the landscape. The IISc logo was first converted to a binary image by applying a thresholding filter. Next, a collection of boundary curves was extracted from the binary image. A clean signed distance field from the set of curves was computed over a unit square. The sign of the distance field essentially segments the image into the blue and golden regions. The distance field is mapped to elevation resulting in a terrain, the IISc logo landscape. Isocontours of the distance field are computed and displayed over the terrain to highlight the valleys. Further details, including a video illustrating the mapping from the signed distance field to the terrain, are available @ http://vgl.csa.iisc.ac.in/iiscLogo/

References:

Parallel computation of 2D Morse-Smale complexes.
Nithin Shivashankar, Senthilnathan M and Vijay Natarajan.
IEEE Transactions on Visualization and Graphics, 18(10), 2012, 1757-1770. (pdf)

Parallel computation of 3D Morse-Smale complexes.
Nithin Shivashankar and Vijay Natarajan.
Computer Graphics Forum (EuroVis 2012), 31(3), 2012, 965-974 (pdf)
Efficient software for programmable visual analysis using Morse-Smale complexes.
Nithin Shivashankar and Vijay Natarajan.
Topological Methods in Data Analysis and Visualization IV.
Hamish Carr, Christoph Garth, and Tino Weinkauf (Eds.)
Springer-Verlag, Mathematics and Visualization Series, 2016, to appear.
http://vgl.csa.iisc.ac.in/pub/paper.php?pid=052

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