- Researchers at Kolkata’s the Indian Institute of Chemical Biology (CSIR-IICB) and the Indian Association for the Cultivation of Science (IACS) have designed and synthesised about 25 quinoline derivatives that show potent anticancer activity.
- The compounds were tested in vitro against human Topoisomerase 1 (topo1) activity and their efficacy to kill cancer cells was carried out using breast, ovarian, cervical and colon cancer cell lines.
- The results of topo1 inhibition activity, cellular mechanisms and the cancer cell line studies carried out at IACS and the compounds designed and synthesised by IICB researchers were published in the Journal of Medicinal Chemistry.
- Preliminary data based on cell line studies suggest that the compounds from IICB might be effective against breast and colon cancer.
- The success of the project is due to the years immaculate design by going back-and-forth with our hypothesis through computational analysis followed by synthesis and X-ray crystallography even before the biological validation began.
An Essential enzyme:
- Topoisomerase 1 is a fundamental enzyme that is essential for replication.
- DNA is in a supercoiled state and has to be unwound before replication can take place.
- For the DNA to uncoil, the topo1 enzyme has to first bind to the DNA and form a complex.
- Once the complex is formed, the topo1 enzyme cleaves one strand of the DNA thus allowing the DNA to uncoil. Once uncoiling is completed, the topo1 enzyme rejoins the cleaved DNA strand for replication to take place.
- It is important to note that existing drugs and the quinoline derivatives synthesised by the IICB team have the ability to trap the complex thereby not freeing the topo1 to rejoin the cleaved DNA strand.
- As the number of trapped complexes in the DNA increases, the amount of free topo1 enzyme available to repair the cleaved DNA strand reduces. Also, other enzymes involved in replication and transcription (where DNA is converted into RNA) come and collide with the trapped topo1 and this causes more DNA breaks.
- As a result, replication gets affected leading to DNA break and cancer cell death.
- The mode of action of the existing drugs and the synthesised compounds is the same. The difference lies in the time the complexes remain trapped when the drugs or the synthesised compounds are used and therefore the ability to kill cancer cells.
- Compared with normal cells, topo1 enzyme is produced in far excess amount in cancer cells and so more complexes are formed.
- As a result, though topo1 enzyme is found even in normal cells, there is greater likelihood of the drugs specifically targeting the cancer cells.
- The existing drugs bind to the complex and trap it only transiently. This is because the drugs can be easily removed by body fluids. So within about 20 minutes, all the DNA breaks are repaired. So the existing drugs have less ability to kill cancer cells.
- It is important to note that the existing drugs are not metabolically stable and so become inactive very fast.
- Hence, using the existing drugs, the complexes can be trapped only for a brief period.
- However, the compound developed by this team of scientists can trap the complex for as long as five hours. All the 25 quinoline derivatives that this team synthesised show similar efficacy towards human topo1 inhibition.
- The ability of the synthesised derivatives to trap the complex for a much longer time might translate into better efficacy in killing cancer cells.
- The speciality of this compound is that they do not react with or bind to topo1 or the DNA when they are in isolation. They bind only when topo1 and the DNA form a complex.
- Thus, the compounds which have been designed by the team can be seen as targeted therapies.
- A new theoretical study from Tata Institute of Fundamental Research finds that Neutrinos could be the driving force behind supernova explosions.
- The study which makes a fundamental advance in modelling neutrinos inside stars puts forth the idea that “fast neutrino oscillations” could hold the key to why some stars explode forming supernovae at the end of their lives.
- Neutrinos come in three flavours: electron neutrino, muon neutrino and tau neutrino, so named because of the corresponding leptons they are associated with (electron, muon and tau).
- There are several puzzles they have posed, including how they are ordered according to mass and this puzzle still remains to be solved.
- Earlier when measuring the number of neutrinos coming from the sun, experimentalists found that only a third of the number of solar neutrinos that was expected was being intercepted on earth.
- This was later explained by the understanding that they have a small mass and they can change from one flavour to another – a phenomenon named neutrino oscillations.
Fast neutrino oscillations:
- When the same neutrinos are in the presence of many other neutrinos and when the different flavours are emitted slightly differently in various directions (anisotropy) the oscillations from one flavour to another happen at a higher frequency.
- This is called fast oscillation and is proportional to the density of neutrinos in the medium, and not the masses of the neutrinos.
- Any star that collapses under its own gravity after having run out of its fusion fuel is called a supernova.
- Usually stars more massive than eight times the Sun’s mass enter this phase of explosive death.
- It is important to note that in earlier work, it was assumed that high density and anisotropy conditions were put in by hand, while the neutrinos were assumed to travel in straight lines without colliding.
- In the present work the authors include collisions that lead to the high anisotropy conditions.
- They show how in the presence of collisions the fast oscillations take place.
- Using two indigenous strains of bacterium isolated from arsenic-contaminated field, researchers from CSIR-National Botanical Research Institute (CSIR-NBRI), Lucknow and the University of Lucknow have shown that arsenic can be effectively removed from contaminated soil with the help of microbes.
- What adds value to these strains (Bacillus flexus and Acinetobacter junii) is the fact that they can promote plant growth too.
Different forms of arsenic:
- Several studies have pointed out that using arsenic-contaminated water for agricultural purposes can lead to increased concentration of arsenic in fruits and grains, proving toxic to humans.
- The researchers studied the two bacteria under different concentrations of arsenate and arsenite, the toxic forms of heavy metal.
- Arsenic treatment did not stunt or delay the growth of both the bacterial strains.
- flexus exhibited resistance to high levels (150 mmol per litre) of arsenate and A. junii to about 70 mmol per litre of arsenite. This is higher than previously reported arsenic tolerant bacteria and so were regarded as hyper-tolerant strains.
- Further gene detection studies pointed out that both the bacteria have a special ars C gene, which aids in arsenic detoxification.
Plant growth promoters:
- The bacterial strains were further scrutinised to understand if they can help in plant growth too. In studies carried out in the lab, both the bacteria were able to solubilise phosphorus. Phosphate solubilising bacteria have been reported to increase phytoavailability of phosphate, thus facilitating plant growth. These two bacterial strains were also found to produce siderophores and ACC deaminase enzyme.
- It is important to note that Siderophore increase the bioavailability of iron and other metal ions in polluted soil environment and ACC deaminase is a well known plant growth promoting enzyme.
- These bacteria can live symbiotically in the roots of plants in arsenic- contaminated soils and help them uptake the required nutrients without causing toxicity.
- The paper published in the Journal of Applied Microbiology notes that these indigenous strains demonstrated the “potential to accumulate arsenic within the cells and transform it into less phytotoxic forms, making the strains more proficient candidate for bioremediation”.
- The Earth and the atmosphere surrounding it receive radiation from the Sun, and get “heated”.
- Some of the gases in the atmosphere, notably carbon dioxide (CO2) absorb this heat radiating from the earth’s surface and bounce it back.
- This is what keeps the earth- land and seas- at a temperature range “comfortable” for us humans and the other organisms inhabiting the earth today. We thus live in a large “green house”.
- However, an important question arises: What happens when the level of these greenhouse gases increases? The temperature will rise. And this rise has been due to increases in the levels of CO2 and other gases, produced upon burning carbon-rich fuels (coal, wood, petroleum products).
- It is important to note that over the last 100 years alone, the global temperature has risen by close to 2 degrees. And if we do not reduce or stop these fuels and use alternate sources of energy (solar, wind and others), the global temperature will rise further.
A Two degree rise has been dangerous:
- We already see it in the form of the melting of ice caps and glaciers, causing a rise in sea level. This can submerge small island countries such as Maldives and Mauritius. It has also led to a change in the global climate, causing errant monsoons, cyclones, tsunamis, El Nino and so on, affecting life on earth and in the oceans (fish, algae, coral reefs).
- Temperature rise and climate change affect not just some countries but the entire globe, on which all species live- humans, animals, plants, fish, microbes. And if it is left uncontrolled, disaster looms for all life across the globe.
- Climate change, plus relentless industrial farming and fishing are leading to the extinction of 1 million species from Mother Earth within decades.
Paris Agreement 2015
- It is for acting against this catastrophe that the UNO brought countries across the world, and in 2015 came up with what is called the Paris Agreement 2015 wherein they decided to make all efforts contain the temperature rise to no more than 1.5 degrees.
- While 195 countries across the globe signed the Paris Agreement and promised to take steps towards it, some oil producing/ importing) countries such as Turkey, Syria, Iran and USA have not.
Steps that need to be taken:
- We need to do two urgent things.
- One is to reduce, indeed replace carbon-based fuels, with other forms of energy generation that do not generate greenhouse gases; hence solar power, wind power and others.
- The second is to enhance all natural methods which absorb CO2. Forests and plants do this best. Photosynthesis is done by all varieties of plants- algae in water, mangroves on the coast, crops and forests on land.
- They absorb atmospheric CO2 and produce oxygen for us to breathe.
- Tropical forests do this best; hence, deforestation in the Amazon, tropical Africa and in India must end.
- These regions also house over 200 million species of plants, animals and fungi.
- They are thus termed as Key Biodiversity Areas (KBAs); likewise are Marine Protection Areas (MPAs). They restore and protect biodiversity, increase yields and enhance ecosystem protection and defense.
- They alone help us preserve over 17% of land realm and 10% of marine areas by 2020, and preserve millions of species from extinction. However, experts opine that we need to do more beyond next year.
Global Deal for Nature
- It is with all this in mind that a diverse group of scientists and ecologists from across the world have come up with a companion pact to the Paris Agreement, called: “A Global Deal for Nature: Guiding Principles, Milestones and Targets”.
- This policy document is published on 19 April 2019 in the journal Science Advances, which should be read by every concerned citizen and government.
- Global Deal for Nature (or GDN) has five fundamental goals:
(1) representation of all native ecosystem types and stages across their natural range of variation;
(2) maintain viable populations of all native species in natural pattern of abundance and distribution – or “saving species”;
(3) maintain ecological functions and ecosystem services;
(4) maximize carbon sequestration by natural ecosystems and
(5) address environmental change to maintain evolutionary processes and adapt to the impact of climate change.
- It is important to note that these five goals of GDN have three Priority themes.
- Theme 1 is on protecting biodiversity. Towards this, they have listed a total of 846 ecoregions across the world and given milestones on how to protect as much as 30% of them by the year 2030.
- Theme 2 is on mitigating climate changes by conserving carbon storehouses or climate stabilization areas (CSAs) and Other Effective area- based Conservation Measures (OECMs).
- Theses involve saving about 18% of existing areas across the world (e.g., tundra, rainforest) as CSAs and about 37% of the areas as OECMs (indigenous peoples’ lands, such as in the Amazon Basin, Congo Basin, Northeast Asia, Continental India).
- Theme 3 is on reducing threats to ecosystems, and concerns reducing major threats (such as overfishing, wild life trade, laying new roads cutting across forest lands, and building major dams).
- In order to do all this, the gross cost is estimated to be $ 100 billion per year.
- Considering that these are over 200 nations across the world (plus the private sector, which too should also be involved), this is a sum well worth achievable if we are to leave the world livable for our children, and all the flora and fauna that have enriched our earth since the last 550 million years.
What is India’s policy for electric vehicles?
- While carmakers in the rest of the world have been focussing on electric cars in the premium segment (costing over ₹10 lakh), India is targeting smaller vehicles.
- The reason for this is, according to NITI Aayog, 79% of vehicles on Indian roads are two-wheelers, while three-wheelers and cars costing less than ₹10 lakh account for 4% and 12% of the vehicle population, respectively.
- Experts opine that concentrating on small electric vehicles will help meet domestic demand and place India in a “position of global leadership”.
- While China, the U.S. and a few European countries offer various subsidies up to 40% to encourage uptake of electric cars, India wants to offer non-fiscal incentives.
- Credits will be offered based on carbon dioxide emissions per km as well as vehicle efficiency.
- While manufacturers exceeding the emission targets will be required to purchase credits, those meeting them will be rewarded.
- The price of the credit will be decided by the market. This approach will make electric vehicles and those with low-emissions cheaper and the polluting vehicles expensive.
- In the next five years, India aims to have at least 15% of electric vehicles on the road. On February 28, India announced the second phase of the Faster Adoption and Manufacturing of (Hybrid and) Electric Vehicles (FAME-2) scheme with an outlay of ₹10,000 crore for a period of three years.
- To encourage faster adoption, incentives will be provided on purchase of an electric vehicle. The scheme will support 10 lakh two-wheelers, 5 lakh three-wheelers, 55,000 four-wheelers and 7,000 buses. While the focus will be on private vehicles for two-wheelers, incentives will be given for three and four-wheelers used for public transport and commercial purposes.
- The aim is to set up charging stations and other infrastructure under ‘Make in India’.
What is the driving range of electric vehicles?
- In electric cars using lithium ion battery (the most widely used battery worldwide), it is between 200 and 300 km per charge.
- The driving range in a city is typically 25-30 km per day. Battery technology to increase driving range and energy density has been, and will continue to be, the focus area in the coming years.
- The most important determinant will be the lifespan of the battery. As per current battery technology, its lifetime will be shorter than the rest of the vehicle.
- According to the European Academies’ Science Advisory Council, some car manufacturers in developed countries are offering an eight-year or 1,60,000 km warranty on batteries.
How long will it take to charge the battery?
- Currently, batteries used in electric cars have capacities of 50 kWh (kilowatt hour) and can be charged overnight using the existing power supply available at home.
- Like in the case of mobile phones, batteries used in electric vehicles can be fast-charged using 7 and 22 kW supply. Charging stations at service stations have 50 or 120 kW supplies and the battery can be charged in 20-30 minutes.
- However, fast-charging causes overheating and degradation, and if done frequently reduces battery life.
Will electric vehicles reduce carbon emission?
- At nearly 55%, electricity generation in India is primarily using coal. Hydroelectric generation is 13% and renewable energy sources including small hydro projects, wind and solar, account for about 21%.
- So like in the case of the U.S. and China, net reduction in carbon emission will not be much even if there is large-scale adoption of electric vehicles in India.
- This is unlike France and the U.K., where non-fossil fuel is a major source of electricity generation. However, cities and town using electric vehicles in large numbers will see a reduction in exhaust-pipe emissions, particularly particulate matter.
- This will be important in the case of India which is home to 14 of the 20 most polluted cities in the world.
Can used batteries be recycled?
- Lithium ion batteries used in electric vehicles can be recycled.
- According to the Financial Times, China and the European Union have rules that make carmakers responsible for recycling their batteries.
- In July 2016, Elon Musk had tweeted that Tesla’s Gigafactory battery factory in Nevada, U.S., will recycle lithium ion battery.
- Li-ion batteries use a “variety of chemical processes, making it difficult to develop standardised recycling”.
- Battery recycling will become an industry by itself by 2025 when used batteries will become plentiful. Eaton, a U.K.-based company, is already selling used electric batteries for reuse as household batteries.
Is there enough cobalt to meet the demand?
- In lithium ion batteries, cobalt is a key component of the cathode (positive electrode).
- Cobalt plays a pivotal role in preventing overheating and provides stability to the battery thus allowing charging and discharging over many years.
- Cobalt is a by-product of mining nickel and copper.
- About 60% of the world’s supply of cobalt comes from the Democratic Republic of Congo, the mining of which has been linked to human rights abuse including child labour.
- As battery technology evolves, the amount of cobalt used may reduce or even stop.
- In May, 2018 Tesla’s battery cell supplier Panasonic Corp said it has already “substantially cut down” cobalt usage and is already “aiming to achieve close to zero usage of cobalt in the near future”.
1. Consider the following statements:
- Any star that collapses under its own gravity after having run out of its fusion fuel is called a supernova.
- Fast neutrino oscillation is proportional to the density of neutrinos in the medium, and not the masses of the neutrinos.
Which among the above statements is/are correct?
a. 1 only
b. Both 1 and 2
c. 2 only
d. Neither 1 nor 2