CLOSE
Original image
The Iceman (reconstruction by Adrie and Alfons Kennis). Image Credit: © South Tyrol Museum of Archaeology, Foto Ochsenreiter

Scientists Find Ulcer-Causing Bacteria in Ötzi the Ice Man

Original image
The Iceman (reconstruction by Adrie and Alfons Kennis). Image Credit: © South Tyrol Museum of Archaeology, Foto Ochsenreiter

In 1991, hikers in the Alps found the body of a Copper Age man preserved in a glacier in the Italian Alps. That body—nicknamed “Ötzi” or “the Ice Man”—has become a rich source of information on Neolithic humans. His latest contribution comes straight from the gut: Scientists have found that Ötzi was infected with the same bacteria that causes ulcers in modern humans.

Ötzi was a survivor; that much is clear. Before he was killed by an arrow to the back about 5300 years ago, he endured parasites, degenerative conditions, and bacterial infections to live to about 45 years of age—an old man, by the standards of his time.

In the two decades since the discovery of Ötzi’s body, scientists have mapped the Ice Man’s plentiful tattoos, sampled his stomach contents to determine his last meal, and sequenced his genome. Now a team of researchers has analyzed his gut bacteria. The results of the study were published online today in the journal Science.

Eduard Egarter-Vigl (left) and Albert Zink (right) taking a sample from the Iceman in November 2010. Image credit: © EURAC/Marion Lafogler

“One of the first challenges was to obtain samples from the stomach without doing any damage to the mummy,” researcher Albert Zink said in a press-only teleconference yesterday. The body was kept frozen to prevent any further deterioration, so the first step was to defrost it. The researchers went in through an incision in Ötzi’s belly made during previous examinations. They took a sample of the Ice Man’s stomach contents and sequenced the DNA of everything they found. From there, they were able to spot and tease out the genomes of specific bacteria—most notably, Helicobacter pylori.

H. pylori is still around today, wreaking havoc in the guts of millions of people around the globe. The bacterium embeds in a person’s stomach lining, causing irritation that can lead to peptic ulcers and stomach cancer. The National Institutes of Health estimate that two-thirds of us are infected with H. pylori, although many people will not have symptoms.

Was Ötzi one of those people? It’s hard to say. His body was well preserved, but some parts had deteriorated over time, including his stomach lining. “He probably had some stomach issues, but we cannot really tell to what extent,” Zink said.

There are several strains of H. pylori, each originating from a different area of the globe. Because Ötzi was discovered on the border of modern-day Italy and Austria, the researchers expected to find the European strain. Instead, they found a strain that’s most commonly found in modern-day Asia, a fact that suggests humans from the two continents were already very familiar with one another.

"This mixing of two bacterial populations can only ever happen if humans actually come together, and by coming together, I mean, intimately," study co-author Yoshan Moodley said in the press conference.

Despite this infection his lactose intolerance, and his hard life, Ötzi was still going strong when he died, the researchers said.

“We think that he could have lived another 10 or 20 years if he wasn't killed by this arrow in his back,” Zink said. “So in the end, it was for sure a tough life in this time period, but with regard to this life circumstance, I think he was still in quite good shape.”

Original image
iStock
arrow
Food
Researchers Pinpoint the Genes Behind the Durian's Foul Stench
Original image
iStock

Durian is a popular fruit in parts of southeast Asia. It's also known for having the most putrid, off-putting odor of any item sold in the produce section. Even fans of durian know why the fruit gets a bad rap, but what exactly causes its divisive scent is less obvious. Determined to find the answer, a team of researchers funded by "a group of anonymous durian lovers" mapped the fruit's genome, as reported by the BBC.

The study, published in the journal Nature Genetics [PDF], contains data from the first-ever complete genetic mapping of a durian fruit. It confirms that durian's excess stinkiness comes from sulfur, a chemical element whose scent is often compared to that of rotten eggs.

Analysis of the fruit's chemical makeup has been done in the past, so the idea that sulfur is a major contributor to its signature smell is nothing new. What is new is the identification of the specific class of sulfur-producing genes. These genes pump out sulfur at a "turbocharged" rate, which explains why the stench is powerful enough to have durian banned in some public areas. It may seem like the smell is a defense mechanism to ward off predators, but the study authors write that it's meant to have the opposite effect. According to the paper, "it is possible that linking odor and ripening may provide an evolutionary advantage for durian in facilitating fruit dispersal." In other words, the scent attracts hungry primates that help spread the seeds of ripe durian fruits by consuming them.

The revelation opens the door to genetically modified durian that are tweaked to produce less sulfur and therefore have a milder taste and smell. But such a product would likely inspire outrage from the food's passionate fans. While the flavor profile has been compared to rotten garbage and dead animal meat, it's also been praised for its "overtones of hazelnut, apricot, caramelized banana, and egg custard" by those who appreciate its unique character.

[h/t BBC]

Original image
iStock
arrow
science
Why DNA Is So Hard to Visualize
Original image
iStock

Picture a strand of DNA and the image you see will likely be similar to the artist’s rendering above. The iconic twisted ladder, or double-helix structure, was first revealed in a photo captured by Rosalind Franklin in the 1950s, but this popular visualization only tells part of the story of DNA. In the video below, It’s Okay to Be Smart explains a more accurate way to imagine the blueprints of life.

Even with sophisticated lab equipment, DNA isn’t easy to study. That’s because a strand of the stuff is just 2 nanometers wide, which is smaller than a wavelength of light. Researchers can use electron microscopes to observe the genetic material or x-rays like Rosalind Franklin did, but even these tools paint a flawed picture. The best method scientists have come up with to visualize DNA as it exists inside our cells is computer modeling.

By rendering a 3D image of a genome on a computer, we can see that DNA isn’t just a bunch of free-floating squiggles. Most of the time the strands sit tightly wound in a well-organized web inside the nucleus. These balls of genes are efficient, packing 2 meters of DNA into a space just 10 millionths of a meter across. So if you ever see a giant sculpture inspired by an elegant double-helix structure, imagine it folded into a space smaller than a shoe box to get closer to the truth.

[h/t It’s Okay to Be Smart]

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios