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In this podcast, I talk to R. Ford Denison of the University of Minnesota. Denison is an evolutionary biologist who's interested in how to make agriculture better. The ways in which plants thrive or fail are shaped by their evolutionary history, as well as the evolution that unfolds every planting season.
We're most familiar with the evolution of resistance to pesticides in insects and to herbicides in weeds. But evolution has many other effects on farms. For example, many important crop plants, like soybeans, cannot extract nitrogen from the atmosphere on their own. They depend instead on bacteria that live inside their roots.
In exchange for fixed nitrogen, the bacteria get nutrients from the plants. It may seem like a happy case of cooperation, but the evolution of cooperation always runs the risk of cheating and deception. How plants and bacteria come to a compromise is a remarkable story that Denison and his colleagues are now documenting.
Cross section though a soybean (Glycine max 'Essex') root nodule. The bacterium, Bradyrhizobium japonicum, infects the roots and establishes a nitrogen fixing symbiosis. This high magnification image shows part of a cell with single bacteroids within their symbiosomes. In this image, you can also see endoplasmic reticulum, dictysome and cell wall.
Download: mp3 (38.5 min | 35.5 megs)
In this podcast, I talk with Irwin Sherman, professor emeritus at the University of California at Riverside, about the century-long quest for a vaccine against malaria.
Scientists have been trying to make a vaccine for the disease almost since the discovery of the parasite that causes malaria. Yet decade after decade, they've encountered setbacks and failures. We talked about why it's so hard to make a malaria vaccine, and how likely it is that scientists will ever be able to do so in the future.
If you want to find out more about this long-running saga, check out Sherman's new book, The Elusive Malaria Vaccine: Miracle or Mirage.
About the Book:Chronicling a 100-year quest, this book tells the fascinating story of the hunt for the still-elusive malaria vaccine. Its clear, engaging style makes the book accessible to a general audience and brings to life all the drama of the hunt, celebrating the triumphs and documenting the failures. The author captures the controversies, missteps, wars of words, stolen ideas, and clashes of ego as researchers around the world compete to develop the first successful malaria vaccine.
The Elusive Malaria Vaccine: Miracle or Mirage? is based on author Irwin W. Sherman’s thorough investigation of the scientific literature as well as his first-hand interviews with today’s pioneers in malaria vaccine research. As a result, the book offers remarkable insights into the keys to a successful malaria vaccine and the obstacles hindering its development.
Malaria is one of humankind’s greatest killers, currently afflicting some 300 to 500 million people. Moreover, malaria infections have begun to spread and surge in places previously free from the disease. With the book’s easy-to-follow coverage of such topics as immunity, immunology, recombinant DNA, and monoclonal antibodies, readers gain a new understanding of the disease itself, the importance of microbe hunters, and the need for responsible leadership to face the challenges that lie ahead in the battle against malaria.
Other Publications from Dr. Sherman:
Download: mp3 (54.5 min | 50 megs)
In this podcast I talk to Keith Klugman, William H. Foege Chair of Global Health at Emory University.
Dr. Klugman studies the disease that is the number one killer of children worldwide. If you guessed malaria or AIDS, you’d be wrong. It’s pneumonia. Two million children under five die every year from it every year--one child every 15 seconds.
Dr. Klugman and I spoke about his research on how pneumonia causes so much devastation, its hidden role in the 50 million deaths in the 1918 flu pandemic, and how a new pneumonia vaccine can stop the disease in its tracks. For more information on pneumonia and how we can all help fight it, visit the World Pneumonia Day web site.
Dr. Peter Daszak is a disease ecologist and President of the Wildlife Trust, an international organization of scientists dedicated to the conservation of biodiversity. He is a leader in the field of conservation medicine and is well known for uncovering the wildlife origin of the SARS virus. Dr. Daszak also identifed the first case of a species extinction caused by a disease and has demonstrated a link between global trade and disease emergence via a process called "pathogen pollution."
In this interview I ask Dr. Daszak about the threat new pathogens pose to endangered species and go into detail about his discovery that chytridiomycosis, a fungal disease caused by the chytrid Batrachochytrium dendrobatidis, is responsible for global amphibian population declines. Dr. Daszack also discusses a unique study that exposes how the W.H.O. might better use their resources when faced with new pathogens such as the kind we've seen with the recent outbreak of the H1N1 virus. We also explore how pathogens of animals have the ability to evolve into human diseases like flu and HIV.
In this podcast I talk to Curtis Suttle, a professor and associate dean at the University of British Columbia.Suttle studies the diversity and population of viruses across the entire planet. He has helped show that viruses are by far the most common life forms on the planet. They also contain most of the genetic diversity of life, and they even control how much oxygen we have to breathe. I talked to Suttle about coming to terms with the fact that we live on a virus planet, and how hard it is to find a place on Earth that's virus-free--even two miles underground.
Links to Curtis Suttle and his work.
Download: mp3 (26.5 min | 25 megs)
In this podcast, I talk to James Collins, an investigator at the Howard Hughes Medical Institute and a professor at Boston University.
Ten years ago Collins helped launch a new kind of science called synthetic biology. I talked to Collins about the achievements of synthetic biology over the past decade, such as engineering E. coli that can count, and about the future of synthetic biology--from using bacteria to make fuel to reprogramming the bacteria in our guts to improve our health.
Download: mp3 (37.5 min | 34 megs)
In this episode, I talk to Michael Worobey, an associate professor at the University of Arizona.
Worobey is virus detective, gathering clues about how some of the world's deadliest pathogens have emerged and spread across the globe. Worobey and I talked about the harrowing journeys he has made in search of the origin of HIV, as well as the round-the-clock data-processing he and his colleagues used to discover the hidden history of the new H1N1 flu strain.
Photos taken in January 2000 in the forest about 60km south of Kisangani DRC during an expedition to collect samples from wild chimpanzee.
In this episode, I speak to Rob Knight, an assistant professor in the Department of Chemistry and Biochemistry at the University of Colorado, Boulder.
Knight studies our inner ecology: the 100 trillion microbes that grow in and on our bodies. Knight explained how hundreds of species can coexist on the palm of your hand, how bacteria manipulate your immune system and maybe even your brain, and how obesity and other health problems may come down to the wrong balance of microbes.
In this episode I speak to Julian Davies, professor emeritus in the Department of Microbiology & Immunology at the University of British Columbia.
Dr. Davies is one of the world's experts on antibiotics. I talked to Davies about how the discovery of antibiotics changed the course of modern medicine, and how we now face a growing threat from the evolution of antibiotic-resistant bacteria. We also talked about some enduring mysteries about antibiotics.
Most of us think of antibiotics as a way to kill microbes. But the fact is that microbes make antibiotics naturally, and for them, these molecules may not be lethal weapons. They may actually be a way to talk to other microbes.
Download: mp3 (28.5 min | 21 megs)
In this episode I speak to Sallie "Penny" Chisholm, the Lee and Geraldine Martin Professor of Environmental Studies at MIT. Dr. Chisholm studies photosynthesis—the way life harnesses the energy of the sun. Plants carry out photosynthesis, but so do microbes in the ocean. Dr. Chisholm studies the most abundant of these photosynthetic microbes, a species of bacteria called Prochlorococcus. There are a trillion trillion Prochlrococcus on Earth. Dr. Chisholm researches these microbial lungs of the biosphere, and how they produce oxygen on which we depend.
Along with her scientific research, Dr. Chisholm is also the author of a new children's book, Living Sunlight: How Plants Bring The Earth To Life.
Download: mp3 (21 min | 16 megs)