pangea's video: The race to create the best Antiviral Drugs - Carl Zimmer

Interview with science writer Carl Zimmer. If you've ever had a bacterial infection like staph or strep throat, your doctor may have prescribed penicillin. But if you've had the flu or a common cold virus, penicillin won't work. That's because antibacterials only kill bacteria, and both the flu and the common cold are viruses. So for illnesses like the flu, doctors prescribe antiviral drugs, which target the mechanisms that viruses use to reproduce. "For example, there are antivirals for the flu that interfere with the virus as it tries to get out of its host cell," says science writer Carl Zimmer. "So this molecule latches on to that particular protein that the virus uses to escape, and interferes with it so that the virus is trapped inside." Zimmer's latest piece for Wired magazine profiles the scientists who are developing antiviral medications, and examines the new ways medicine is working to attack viruses. "There's this whole ecosystem of interactions going on inside our own bodies that we do not understand — barely at all," he says. "Scientists are just starting to figure it out with very big projects where they're sequencing all the genes these microbes have. But they're just at the beginning of understanding it." Did viruses help make us human? As weird as it sounds, the question is actually a reasonable one to ask. And now scientists have offered some evidence that the answer may be yes. If you’re sick right now with the flu or a cold, the viruses infecting you are just passing through. They invade your cells and make new copies of themselves, which burst forth and infect other cells. Eventually your immune system will wipe them out, but there’s a fair chance some of them may escape and infect someone else. But sometimes viruses can merge into our genomes. Some viruses, for example, hijack our cells by inserting its genes into our own DNA. If they happen to slip into the genome of an egg, they can potentially get a new lease on life. If the egg is fertilized and grows into an embryo, the new cells will also contain the virus’s DNA. And when that embryo becomes an adult, the virus has a chance to move into the next generation. These so-called endogenous retroviruses are sometimes quite dangerous. Koalas, for example, are suffering from a devastating epidemic of them. The viruses are spreading both on their own from koala to koala and from parents to offspring. As the viruses invade new koala cells, they sometimes wreak havoc on their host’s DNA. If a virus inserts itself in the wrong place in a koala cell, it may disrupt its host’s genes. The infected cell may start to grow madly, and give rise to cancer. If the koalas manage to survive this outbreak, chances are that the virus will become harmless. Their immune systems will stop their spread from one host to another, leaving only the viruses in their own genomes. Over the generations, mutations will erode their DNA. They will lose the ability to break out of their host cell. They will still make copies of their genes, but those copies will only get reinserted back into their host’s genome. But eventually they will lose even this feeble ability to replicate. We know this is the likely future of the koala retroviruses, because we can see it in ourselves. Viruses invaded the genomes of our ancestors several times over the past 50 million years or so, and their viral signature is still visible in our DNA. In fact, we share many of the same stretches of virus DNA with apes and monkeys. Today we carry half a million of these viral fossils, which make up eight percent of the human genome.