RM had his first out-of-body experience at the age of 16. Now, at the age of 55, he has had more than he can count. They usually happen just before he falls asleep; for ten minutes, he feels like he is floating above his body, looking down on himself. If the same thing happens when he’s awake, it’s a far less tranquil story. The sense of displacement is stronger – his real body feels like a marionette, while he feels like a puppeteer. His feelings of elevation soon change into religious delusions, in which he imagines himself talking to angels and demons. Psychotic episodes follow. After four or five days, RM is hospitalised.
This has happened between 15 to 20 times, ever since RM was first diagnosed with schizophrenia at the age of 23. He hears voices, and he suffers from hallucinations and delusions. Despite these problems, he managed to hold down a job as a reporter until 2002 and more recently, he has been working in restaurants and volunteering as an archivist. Then, about a year ago, he took part in a study that seems to have changed his life.
There is a vast, unseen marketplace that connects us all. The traders are the trillions of bacteria that live on or within our bodies; the commodities they exchange are genes. This flow of genes around our bodies allows bacteria to rapidly evolve new skills, including the abilities to resist antibiotics, cause disease, or break down environmental chemicals. In the past, scientists have caught glimpses of individual deals, but now the full size of the marketplace is becoming clear.
The human body is home to 100 trillion microbes, whose cells outnumber ours by ten to one, and whose genes outnumber ours by a hundred to one. These genes are not only more numerous than ours, but they operate under different rules. While we can only pass down our DNA to our children, bacteria and other microbes can swap genes between one another. For example, the gut bacteria of Japanese people have a gene that helps them to digest seaweed. They borrowed it from an oceanic species that hitched its way into Japanese bowels, aboard uncooked pieces of sushi.
This was an isolated example, but such ‘horizontal gene transfers’ are fairly commonplace. When Chris Smillie and Mark Smith from MIT looked at the genomes of over 2,200 species of bacteria, they found 10,000 genes that had been recently swapped. These genes were more than 99 percent identical, even though they came from bacteria that were distantly related*. Standing out like beacons of similarity amid seas of difference, they must have been transferred from one species to another, rather than inherited from mother cell to daughter.
The first episode of Frozen Planet – the BBC’s new mega-series on life at the poles, fronted by the peerless David Attenborough – aired on Wednesday. It exceeded my already lofty expectations, and I’ve written a comment piece for the Guardian that’s a bit of a love letter to the makers of the show, the BBC’s Natural History Unit, and the BBC’s attitude to science programmes more generally. Extract below; go read the whole thing.
Giant unicorn-whales with tusks? That’s why I pay my licence fee
Here is what I do when I’m feeling down about the country: I load up the Wikipedia page for the BBC Natural History Unit and click on the “In Production” link. Happy sighs ensue.
The unit’s latest product, aired on Wednesdays, is Frozen Planet, a majestic tour of Arctic and Antarctic wildlife ably narrated by Sir David Attenborough, an 85-year-old man who insists on travelling to the south pole while people many decades his junior make a small noise whenever we sit down.
On the screen, polar bears mate and fight, wolves run down herds of bison and lunging whales create concentric ripples of fleeing fish. It would take several thousands of pounds to see these sights in person, but for £145.50 a year, I can recline on my sofa and watch the world’s jammiest penguin escape from the world’s most incompetent sea lion. From the screen, that velvety voice: “Never have the roles of hunter and hunted been played with so little skill.” Fortunately, the same can’t be said for the people behind the cameras.
Photo via BBC NHU
In comic books, many superheroes have gained extraordinary powers after being transfused with the (often modified or irradiated) blood of animals. But, as so often happens, life proves stranger than fiction. At the University of Colorado, Boulder, a group of mice have grown bigger hearts after scientists injected them a chemical cocktail, inspired by the blood of pythons.
When the situation demands it, the muscles of mammal hearts grow larger and pump more vigorously. That’s useful for pregnant women who need to pump for two, toddlers who need to fuel their rapid growth, or athletes who need to power their regularly exercise. But growing hearts can also be bad news if they’re triggered by genetic disorders, high blood pressure or heart attacks. These situations can cause “hypertrophic cardiomyopathy”, where the heart’s thickening walls force it to work harder to pump blood.
To understand how hearts get bigger, Cecilia Riquelme turned to an animal whose heart swells in size every time it eats – the Burmese python. Pythons can swallow extremely large prey like pigs or deer, and they remodel their organs to cope with their meals. Their intestines and liver nearly double in size. As, as Stephen Secor discovered in the 90s, their hearts become 40 percent bigger in just two to three days. For comparison, most mammal hearts only become 10 to 20 percent bigger after months of exercise.
It’s a seemingly simple idea: if you can find the genetic changes that turn normal cells into cancerous ones, you could find new ways of treating cancer. But that’s easier said than done. The genome of a cancer cell is a chaotic mess. Typos build up throughout its DNA, corrupting the encoded information. Entire sections can be flipped, relocated, doubled and deleted. Some of these changes drive the cells to grow and multiply uncontrollably; others are irrelevant passengers that are just along for the ride. Separating the former form the latter is like finding a needle in a haystack made of needles.
And that’s exactly what Elisa Oricchio from the Sloan-Kettering Memorial Cancer Center has done. Using powerful genetic techniques, she has identified a gene – EPHA7 – whose loss can lead to a sluggish but hard-to-treat type of lymphoma called follicular lymphoma. The gene encodes a protein of the same name, and Oricchio even used the EPHA7 protein to shrink the size of tumours in mice with lymphoma.
The hagfish looks like an easy meal. Its sinuous, eel-like body has no obvious defences, but any predator that moves in for a bite is in for a nasty surprise. The hagfish releases a quick-setting slime that clogs up the predator’s gills, causing it to gag, choke and flee. Scientists have known about this repulsive defence for decades, but Vincent Zintzen has finally filmed it in the wild. His videos also prove that hagfish, generally thought to be scavengers of the abyss, are also active hunters that can drag tiny fish from their burrows.
The answer is… not a lot. Well, actually, a bit. Look, it’s complicated. There’s a new study out that tries to answer this question and I’ve written about it for Nature News. Here’s the summary, but do read the full piece – the really interesting thing here is the potential for future experiments that will actually be able to test some of the grandiose claims that adorn yoghurt packets.
Many yoghurts are loaded with live bacteria, and labelled with claims that consuming these microorganisms can be good for your health. But a study published today shows that such yoghurts have only subtle effects on the bacteria already in the gut and do not replace them.
Nathan McNulty, a microbiologist at Washington University in St Louis, Missouri, recruited seven pairs of identical twins, and asked one in each pair to eat twice-daily servings of a popular yoghurt brand containing five strains of bacteria.
By sequencing bacterial DNA in the twins’ stool samples, the team showed that the yoghurt microbes neither took up residence in the volunteers’ guts, nor affected the make-up of the local bacterial communities.
McNulty also fed the five bacterial strains from the yoghurt to ‘gnotobiotic’ mice — animals raised so that the only microorganisms that their guts contain are 15 species found in humans.
As with the twins, the yoghurt bacteria did not change the composition of the rodents’ resident communities. However, the activity of genes that allow the native bacteria to break down carbohydrates did increase.
We’re in western America in the late Jurassic period, and a herd of Camarasaurus dinosaurs is on the move. It’s the dry season and the giants are running out of water. Fortunately, they know exactly where to find a drink: a range of volcanic highlands to the west. To quench their titanic thirst, they must head for the hills. Now, 150 million years later, Henry Fricke from Colorado College had discovered a way of reconstructing their migration.
Vast migrations are a common feature among modern animals, and it’s reasonable to think that some dinosaurs undertook similar treks. But how do you work out the routes of long-extinct animals, when you only know about the spot where they died? The answer, as with many aspects of dinosaur life, is to look at their skeletons. As well as revealing the shape and size of these beasts, dinosaur fossils can also hold a record of their travel plans.
Such is the life of the Australian plague locust, a common pest that is targeted by the black digger wasp. The wasp is a parasite that creates living larders for her grubs. She stocks them with the bodies of paralysed insects. Last December, the locusts formed dense plagues in southeastern Australia just as the wasps were starting to collect fresh meat for their young. And Darrell Kemp from Macquarie University was watching as the two species collided.