A recent study published in the journal Applied Physiology, Nutrition and Metabolism has some very exciting findings in the fight against memory loss and dementia. I probably don't need to tell you how debilitating dementia can be if you've experienced it with someone you care about. If you haven't, count yourself lucky. The World Health Organization (WHO) says that around 50 million people worldwide have dementia. Nearly 60 percent live in low- and middle-income countries. Every year, there are nearly 10 million new cases. And to make matters worse, the total number of people with dementia is projected to reach 82 million in 2030 and 152 million by 2050. Currently, there's no treatment or cure for dementia or even a way to alter its progression. That makes preventative treatments, such as the study I'm focussing on today, even more exciting. Thankfully, numerous new treatments are being investigated, which are at various stages of clinical trials. So it's not all doom and gloom. Exercise affects the brain in many ways. To start with, exercise generally increases your heart rate, which in turn pumps more oxygen to the brain. Exercise aids the release of hormones, which provide an excellent environment for the growth of new brain cells. Exercise also promotes brain plasticity by stimulating the growth of new connections between cells in many important cortical areas of the brain. Research from UCLA even demonstrated that exercise increased growth factors in the brain, which makes it easier for the brain to grow new neuronal connections....

Neurons communicate with each other via electrical impulses, which are produced by ion channels that control the flow of ions such as potassium and sodium. In a surprising new finding, MIT neuroscientists have shown that human neurons have a much smaller number of these channels than expected, compared to the neurons of other mammals. The researchers hypothesize that this reduction in channel density may have helped the human brain evolve to operate more efficiently, allowing it to divert resources to other energy-intensive processes that are required to perform complex cognitive tasks. “If the brain can save energy by reducing the density of ion channels, it can spend that energy on other neuronal or circuit processes,” says Mark Harnett, an associate professor of brain and cognitive sciences, a member of MIT’s McGovern Institute for Brain Research, and the senior author of the study. Harnett and his colleagues analyzed neurons from 10 different mammals, the most extensive electrophysiological study of its kind, and identified a “building plan” that holds true for every species they looked at — except for humans. They found that as the size of neurons increases, the density of channels found in the neurons also increases....

The Bio Revolution has the potential to transform our lives, and genome editing—the ability to change the DNA sequence in a targeted way using CRISPR-Cas9, is one of the key innovations that has sparked imaginations while also raising its fair share of controversy. What is the origin of this technique? How do we weigh the enormous benefits against the potential risks? And what is its role in solving the global coronavirus pandemic? As part of the McKinsey Global Institute’s research on the Bio Revolution, partner Michael Chui spoke with Jennifer Doudna, PhD, one of the scientists who discovered the genome-editing technique CRISPR-Cas9 and leading proponent of its responsible use. Jennifer is a professor of molecular and cell biology and chemistry at the University of California, Berkeley. The Doudna lab pursues a mechanistic understanding of fundamental biological processes involving RNA molecules. Michael Chui: Jennifer Doudna, thanks for joining us today. We want to cover a lot of different things today. But why don’t we start with where we are today. We’re in a unique biological moment, you might say. We’re recording this in mid-April 2020, and we’re sheltering in place. This is an event that’s affecting everyone. And I’d love to ask you about this. What has the COVID-19 pandemic been like for you? Jennifer Doudna: Like everyone, it’s a strange moment we’re in right now. It’s an odd experience to be sequestered at home doing what we can, both professionally and personally, to keep our sanity and possibly contribute to mitigating the effects of this disease. It’s a time when many of us are discovering things, or rediscovering things, about ourselves. I’ll give you an example for myself. I’m an avid gardener but I haven’t had any time to work in my garden for, I don’t know, six or seven years with all the craziness going on with CRISPR and work that I’ve been doing at the university. This past month or so has been an opportunity to reconnect with my garden, my flowers, and rediscover what it means to have a more of a balanced life. That’s the silver lining, I suppose, to this current moment. Professionally, it’s been an opportunity to pull together with colleagues and ask ourselves, “What can we do as scientists to address this current national and international emergency?” As you may know, we’ve been able to pull a team of scientists and computer specialists together at the Innovative Genomics Institute here in the Bay Area of California, to build a clinical testing lab that is now testing patient samples for the presence of the coronavirus. And in the future, we will also help some local teams to test new types of diagnostics that could eventually provide an at-home test for this and future viruses. It’s been a really extraordinary time in many ways. Michael Chui: Now, I think a lot of people who are listening probably have watched your TED Talk or, otherwise heard of CRISPR. But if you don’t mind can you explain what that technique is? Jennifer Doudna: CRISPR is a nice segue from talking about a pandemic caused by a virus, because CRISPR is, in fact, a bacterial immune system. It’s an ancient system that evolved in microbes to allow prevention of viral infection. Our interest in this started with that fundamental biology, asking, “How does this work?” We did a collaborative research project with Emmanuelle Charpentier, a medical microbiologist, and our work with her laboratory revealed that one of the components of this CRISPR immune system is, in fact, a protein that’s called Cas9, that can be programmed to find and cut virus DNA. ...

Hello Nature readers,Today we learn that China has joined the international vaccine coalition COVAX, enjoy rediscovering the work that won this year’s science Nobels and hear what Germany’s leading pandemic scientist says about what’s to come. China announced today that it will join COVAX, the international coalition that aims to fairly distribute COVID-19 vaccines. The effort — run by Gavi, the Vaccine Alliance; the Coalition for Epidemic Preparedness Innovations; and the World Health Organization — wants to provide 2 billion vaccine doses to the most-vulnerable people and to health-care workers, especially in poor countries. Some 80 wealthy countries have committed to support the initiative, with the notable exception of the United States. It is not clear yet whether China will commit money or vaccines, and how much. This week, a giant fire in northern California reached ‘gigafire’ status. It burnt more than one million acres over weeks — the largest wildfire the state has ever seen. “It makes up more than all of the fires that occurred between 1932 and 1999,” said Gavin Newsom, the state’s governor. “If that’s not proof-point testament to climate change, I don’t know what is.” California experienced its hottest August on record this year, after years of below-average rainfall. These factors contributed to ideal conditions for the worst fire season the state has ever recorded; 4 million acres have burnt so far. It’s Nobel’s week! Half the fun of which is rediscovering the work that has taken home the prize this year — and the fascinating scientists behind it. Microbiologist Emmanuelle Charpentier and biochemist Jennifer Doudna shared the chemistry Nobel for developing the precise genome-editing technology CRISPR. Virologists Harvey Alter, Michael Houghton and Charles Rice shared the medicine Nobel for research on hepatitis C, the virus responsible for many cases of hepatitis and liver disease. Mathematical physicist Roger Penrose shared the Nobel prize in physics with astronomers Andrea Ghez and Reinhard Genzel, who discovered a giant black hole in the centre of the Galaxy. This week, the Nature Podcast speaks to Lauren Wolf, the US bureau chief of Nature’s news team, and our US-based reporter Jeff Tollefson about why Nature must cover politics and what’s at stake in the upcoming US presidential election. “I think the short answer is: everything,” says Tollefson, who wrote a feature on how Trump damaged science, and why it could take decades to recover. The coronavirus pandemic has put a harsh spotlight on the connections between science, politics and policy, he says. “This touches on public health, it touches on just how science is used across the US government, it touches on issues of scientific integrity — and frankly it touches on issues of democracy.” Plus, the podcast explores whether maternal behaviours are learned or innate, and I drop in to chat about the Nobel winners. Virologist Christian Drosten, who is leading Germany’s response to the COVID-19 pandemic, addresses everything from testing strategies to whether to eat inside a restaurant in a wide-ranging interview with Die Zeit. “I think we need to start preparing people now for a vaccine that may not be perfect,” he says. He also looks forward to returning to his normal life as an anonymous scientist. “I hope that people will then forget about me, that in a few years’ time, newspapers will write a ‘Where Are They Now?’ story about Christian Drosten.” Today, our favourite flightless adventurer is hiding out at the thermal springs of Pamukkale in southwest Turkey. Can you find Leif Penguinson? The answer will be in Monday’s e-mail, all thanks to Briefing photo editor and penguin wrangler Tom Houghton. Yesterday I wrote that chemist Mario Molina was Mexico’s only Nobel laureate. He was of course the country’s only science Nobel winner. Diplomat and politician Alfonso Garcia Robles was awarded the Nobel peace prize in 1982, for his work on nuclear disarmament. And author and diplomat Octavio Paz won the Nobel Prize in literature in 1990. I’m sorry for the error and I’m grateful to all of you who flagged it. This newsletter is always evolving — tell us what you think! Please send your feedback to briefing@nature.com. Flora Graham, senior editor, Nature Briefing With contributions by Nicky Phillips ...