Nobel Prizes 2015 – the Lowdown
Welcome to my round-up of the new Laureates of the Nobel Prizes 2015! What do you think of this year’s haul? The winners this year have included scientists that helped discover cures for deadly parasitic diseases, disprove a major assumption physicists had made about the fundamental properties of the Universe, and work out how cells help stop their DNA falling apart. Enjoy!
All images are from official Nobel Prize online information unless otherwise stated.
The Medicine Nobel Prize 2015 winners this year have done nothing less than discover drugs that have saved hundreds of thousands of lives.
50% of the Prize is shared between Japanese microbiologist Satoshi Omura and US parasitologist William C. Campbell. Omura worked with Streptomyces soil bacteria that were rather good at killing off other organisms. To figure out what exactly the Streptomyces were producing that was so deadly, he carefully developed thousands of slightly different strains. Omura then whittled them down to the 50 candidates he deemed most likely to produce something useful.
These candidates were tested by Campbell, who was particularly impressed by the anti-parasitic abilities of a strain called Streptomyces avermitilis. The active substance called Avermectin was extracted and modified into an enhanced form called Ivermectin that can be used as a drug. Ivermectin can be given to humans or animals and kills off a range of parasites in their larval form.
The other 50% goes to Youyou Tu. She was searching for an alternative malaria drug because the parasite was becoming resistant to quinine and chloroquine, the best available drugs at the time. A large screen had highlighted extract from a plant called Artemisia annua as effective, but what exactly the active substance in this plant was, or how best to extract is, was unknown. Tu studied traditional Chinese medicine texts and found clues which informed her own purifications to develop the drug Artemisinin. This drug was so powerful because it worked on an early stage of parasitic development.
Their legacy remains. Ivermectin is still used today by those suffering parasitic infections that cause terrible conditions including river blindness and lymphatic filariasis. Tu’s Artemisinin forms part of current malaria combination therapies which have reduced deaths from this disease by over 20%.
Both drugs were isolated from natural sources. There is still so much of the natural world we haven’t explored – in deep rainforests and deeper oceans – that may contain the next major cure. The awarding of this Nobel Prize highlights not only the innovation of scientists, but also the desperate importance of conserving the natural world.
You are swarming with neutrinos. Millions of these ghostly particles pass through your body every second but they’re so hard to detect, it took twenty six years to go from theoretical postulation to actual real-life discovery. The work of the Nobel Laureates this year built upon this, realising that neutrinos are changelings; they’re switching form all the time. This finding has serious implications for the way physicists describe the rest of the universe as told by the Standard Model of the universe.
The two Laureates were working in research labs on opposite sides of the globe, each looking at neutrinos from different sources. Takaaki Kajita was working at the Super-kamiokande observatory in Japan, looking at neutrinos formed in the atmosphere from reactions with cosmic radiation. Meanwhile Arthur B. Macdonald was studying neutrinos coming to Earth from the Sun, and trying to solve a rather puzzling problem.
This was the issue: of all the neutrinos heading our way from the Sun, only a third were actually reaching us. What was happening to the two thirds that didn’t make it? Given how weakly they interact with matter, they couldn’t all have bumped into something on their way here!
Kajita’s group in 1998 first found evidence of neutrinos switching flavours. In 2001, the Canadian group recognised this was happening in neutrinos from the Sun. The equipment had been set up to detect only one of three flavours, but many neutrinos had changed form during their journey to Earth. The neutrinos hadn’t disappeared or gone somewhere else, they’d just shifted into something else.
The mystery was resolved, but it led to an even bigger problem for physicists to work on. Neutrinos can only switch forms if they have mass, however small. Yet the Standard Model of physics was working on the assumption that neutrinos are massless. They are not. This means that the Standard Model alone is not enough to explain the building blocks of our Universe. As ever, more research is needed.
Chemistry – DNA repair
DNA is beautiful, necessary and breaks a lot. Our cells keep their “master copy” of their genetic code tucked away as safe as possible in the nucleus, but it’s a thin, fragile molecule. It often breaks spontaneously, especially when being copied during cell division. Add in UV radiation and a whole host of chemicals actively disrupting the structure, and it’s pretty clear DNA needs help holding itself together.
Each of the Chemistry Laureates of 2015 have been involved in figuring out the molecular details of a different type of DNA repair. Thomas Lindahl from the UK discovered base excision repair after realising that DNA mutates and breaks so rapidly that complex life simply couldn’t have evolved without some form of repair. Base excision repair fixes small errors in the code which build up randomly over time.
Aziz Sancar from the USA worked on a different pathway called nucleotide excision repair, which fixes the bulkier bugs that are often caused by UV radiation. Overloading this pathway with intense sunlight for too long is one of the main factors in skin cancer.
Paul Modrich, also from the USA, looked at errors particular to cell division, when the DNA goes through a series of complicated processes. Fixing these errors is called mismatch repair, and chances of developing cancer increase 1000-fold if something goes wrong with it.
If DNA errors aren’t fixed in time, they can become permanent mutations within cells. If the mutation happens to be in an important gene, it might just lead to that cell turning cancerous. The more we understand about all of our DNA repair pathways, the better we can help our cells help themselves, putting the break on cancer before it has a chance to take hold.