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Devangshu Datta: The discoveries that saved lives

An entire generation owes its respite from killer diseases to the physiological researchers awarded the Nobel this year

Devangshu Datta 

Devangshu Datta

The 2015 Nobel Prize for Physiology or Medicine goes to work with huge practical applications. The prize was divided, one half going jointly (meaning a quarter each) to William C Campbell and Satoshi Omura "for their discoveries concerning a novel therapy against infections caused by roundworm parasites". The other half went to Youyou Tu "for her discoveries concerning a novel therapy against malaria".

The three recipients discovered, and developed, two key drugs that tackle parasite-driven diseases. Those drugs have spared millions from untold misery and death. There has been strong public resonance, especially to the story of Tu's research.

The story of Project 523 (it began on May 23, 1967) has often been told. Chairman Mao demanded an effective anti-malarial drug for the People's Liberation Army (PLA). Units of the PLA posted in Vietnam were suffering from malaria, endemic to Indochina.

Tu and her team isolated the active ingredient, artemisinin, from the wormwood flower used in traditional remedies. Tu found a clever way to isolate the active ingredient. Other scientists found the drug has a unique crystalline structure. It has a peroxide bridge, which has never been found in any other naturally-occurring chemical. Tu and her team took major personal risks, in experimenting on themselves. Artemisinin has saved tens of millions of lives.

Omura cultured Streptomyces avermitilis, a member of the streptomycin family. This was the source of avermectin, a drug which kills the roundworm parasites that cause river blindness and lymphatic filariasis (elephantiasis). Campbell was an expert in parasite biology. He discovered the anti-parasitical properties of avermectin. Importantly, a small dose administered just once or twice annually kills parasites without harming the hosts. About 200 million people have taken avermectin.

The chemistry Nobel was awarded jointly to Tomas Lindahl, Paul Modrich and Aziz Sancar for "mechanistic studies of DNA repair". The trio mapped repair mechanisms within cells and found explanations for how DNA information is protected, backed up and errors repaired.

DNA - the double helix - preserves all genetic information. Every cell contains the DNA unique to that individual, which is faithfully copied. A human body contains billions of cells and that of some other species contain even more cells. What is more, cell division and regeneration are continuous.

How is DNA fidelity maintained across so many copies? How is the genome 'proof-read' for errors and how are corrections applied? The trio who won the chemistry Nobel, independently discovered and mapped many of these processes.

Lindahl found that DNA suffered many potential dangerous injuries every day. He worked out how DNA repairs itself from such natural damage, by using certain enzymes. Sancar was interested in post-radiation repair, when cells are exposed to radiation including the ultra-violet radiation present in sunlight. He discovered a light-sensitive repair enzyme for UV radiation and then found another enzyme, which worked in the dark.

Modrich found that the enzyme, dam methylase, was key to identifying DNA mismatches. When a cell replicates, DNA sections that don't match the original are identified by this enzyme. He subsequently worked out some other enzymes key to the identification process.

The Nobel Prize in Physics 2015 was awarded jointly to Takaaki Kajita and Arthur B McDonald "for the discovery of neutrino oscillations, which shows that neutrinos have mass". This is perhaps the most obscure of the awards.

Neutrinos are particles that pass through almost everything, making them hard to study. Wolfgang Pauli, who postulated their existence in a theoretical paper in 1930, doubted they existed. The Standard Model of physics postulates three types of neutrinos. These particles were assumed to be mass-less.

Kajita and McDonald were in different research teams. They discovered independently that neutrinos can transform from one type into another. This cannot happen unless the neutrinos have mass. It is the first time experimental data has conflicted with the Standard Model. More work needs to be done and the implications are far-reaching.

In DNA repair as well, the entire mechanism is not well understood and more breakthroughs could have positive consequences for cancer research, among other things. Where malaria and filaria are concerned, other drugs must soon be developed to counter drug resistance and other methods of disease eradication are also important. But an entire generation owes its respite from killer diseases to the trio of physiological researchers honoured this year.

First Published: Thu, October 15 2015. 21:48 IST
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