January 17th, 2013
1 minute read
Within our DNA are the remains of thousands, maybe millions, of genetic nomads. They once roamed free through the landscape of our genomes; now most are silenced and still, unable to move. These are the ‘jumping genes’, or ‘transposable elements’ to give them their proper name; curious stretches of mobile DNA. Almost 50% of our DNA is made of these remnants. We see them in virtually all organisms, from bacteria, insects and fish all the way through to us humans. In mammals the only active jumping genes we’ve seen are a type called retro-transposons, which scatter copies of themselves throughout genomes. Now a new DNA sequence for a different type of jumping gene, the first active example of its kind ever to be seen in a mammal, has been spotted jumping around in the genome of the brown bat.
December 28th, 2012
1 minute read
You’re not just eating for one. You’re eating for trillions. We like to think of ourselves as an individual, but the truth is we are never alone. We are a buzzing hive of bacteria and other microbes that make up our ‘microbiome’. They eke out a living in whatever niches they can find, our skin or parts of our digestive system; we are an ecosystem. Like all ecosystems there is competition for resources, and some microbes don’t take it lying down, they fight. I’ve written before about Cholera’s spring loaded dagger, but microbes have many means at their disposal, some release enzymes to chew off important bits of their competitors, or poison them. But a few go a step further; they use biological warfare: unleashing viruses to kill off the competition.
November 11th, 2012
1 minute read
Like a kind of Russian doll infection, a prolific human parasite—responsible for almost 250 million infections annually—can itself harbour a parasite, a virus. You might reasonably feel a sense of something akin to schadenfreude; glad it’s getting a dose of its own medicine, so to speak… But you may be too hasty. The very presence of this virus—though it doesn’t infect human cells—in its parasite host could be making infections worse, or even stymying our attempts at relieving the infection. The parasite in question, with around 3.7 million people infected in the US alone, is the most common protozoan infection in the industrialised world: Trichomonas vaginalis (TrV). It infects the human genitourinary tract of both men and women causing Trichomoniasis; in fact, it can only live in the human genitourinary tract (an ‘obligate human parasite’). Women are more likely to experience symptoms than men, and while generally mild, it can be bad. Its ...(Read More)
November 2nd, 2012
4 minute read
Nestled safely away within your cells, among your DNA, lies something…foreign. An invader. Something you weren’t born with, hidden, evading your immune system and waiting to make its next strike: a ‘latent’ virus. In all probability, there are armies of different viruses performing this same trick throughout your body. Remaining silent; some of their own mysterious accord, others kept in check by your immune system or by random mutations, rendering them useless. Now researchers at The Ohio State University and the University of Oxford have worked out how some of these viruses can reactivate in healthy people, and once again go about their nefarious mindless deeds: hijacking our cells machinery, producing more of their own kind, and causing disease. An inefficient virus kills its host. A clever virus stays with it. — James Lovelock In healthy people latent viruses aren’t generally a problem, occasionally annoying, but rarely life threatening. However, ...(Read More)
September 14th, 2012
4 minute read
Taming the power of the immune system in the lab wasn’t easy. For a start, it was a mystery how we have so many different antibodies, millions at any one time. But if it’s one gene per protein, and we only had something like 30,000 genes, how could we have millions of different antibodies? Understanding this problem was the key that unlocked one way to make antibodies against targets that we select. We can use them as tools in the lab, or to treat disease—therapeutic antibodies. Chances are you may know someone who has, or is, using them; if they have Crohn’s disease for example. Just finding antibodies that stick to a target—some unique bump, crevice or corner on a virus, for example—isn’t enough. The next step is to find out if they do something useful. They may stick but not prevent infection, or not activate some receptor on a ...(Read More)