These Algae Live Inside Growing Baby Salamanders

© Roger Hangarter
© Roger Hangarter

Nature has produced some very odd couples. One of the most beautiful and bizarre may be the duo of green algae and baby salamanders. It’s a relationship that has fascinated scientists for more than a century. Now a new paper in the journal eLife sheds a little light on their weird and wonderful dynamic.

Mutually beneficial relationships between species are a dime a dozen, lead author John Burns of the American Museum of Natural History said in a statement, “but the relationship between this particular alga and salamander is very unusual.”

The alga Oophila amblystomatis and its pal, the spotted salamander, don’t just hang out in a living room somewhere. The beautiful, grassy green alga enters the salamander’s jelly-like egg—and then enters the cells of the salamander itself.

The in-egg cohabitation seems to benefit both parties. The alga makes oxygen for the salamander, and the salamander makes nitrogen for the alga through its waste.


© Roger Hangarter

It’s a “strange arrangement,” said co-author Ryan Kerney of Gettysburg College. But how does it work?

To find out, Kerney, Burns, and their colleagues analyzed both species’ cells at the molecular level. They looked at the RNA of algae that lived with and inside salamanders; algae that didn’t; salamanders that lived with algae; and salamanders that didn’t.

They found that, as with any intense relationship, being together changed things for both partners. For the algae, the changes weren’t all positive: those living inside salamanders showed signs of stress and difficulty adapting. This is not a huge surprise; green algae ordinarily get their energy from the Sun. Moving inside an animal’s sunless body would be a pretty big shock.

The same was not true for the salamanders. The results showed that their bodies changed to become more hospitable for the algae by suppressing their immune systems, which suggests that they may have something to gain by letting the algae in.

Learning more about these two weirdos could teach us more about the way the rest of the natural world works.

“These two fundamentally different cells are changing each other dramatically,” co-author Eunsoo Kim of AMNH said. “This might be relevant for other symbiotic systems, including human and parasitic microbe relationships.”

For the First Time Ever, a Woman Has Won the Abel Prize—Math's Version of the Nobel Prize

iStock.com/perfectlab
iStock.com/perfectlab

Every year since 2003, the Norwegian Academy of Science and Letters has bestowed the Abel Prize for excellence and contributions in the field of mathematics. Every year, the recipient has been a man. In 2019, Karen Uhlenbeck crushed that dubious tradition and became the first woman to win the Abel Prize and its $700,000 award.

An emeritus professor at the University of Texas at Austin, Uhlenbeck’s work is focused on gauge theory and geometric analysis—the latter a field she pioneered. Gauge theory supports theoretical physics and is involved in the research of particle physics and string theory. Uhlenbeck is also credited with work that led to greater comprehension of the unification of forces, a primary objective in physics that attempts to link electromagnetic force and weak nuclear force with strong nuclear force in a single theory, which would help us understand the universe.

Mathematician and Abel Prize winner Karen Uhlenbeck is seen in a portrait
Courtesy of the University of Texas at Austin

Uhlenbeck arrived at UT Austin in 1987 and stayed after her retirement in 2014. During that time, she co-founded several programs, including the Saturday Morning Math Group and Distinguished Women in Mathematics lecture series, both in Texas, as well as the Park City Mathematics Institute and the Woman and Mathematics program at the Institute for Advanced Study in Princeton, New Jersey.

She achieved another milestone in her field in 1990, when she became the second woman (and the first since 1932) to host a plenary lecture at the International Congress of Mathematicians.

The Abel Prize, which is modeled after the Nobel Prize, is named after Norwegian mathematician Niels Hendrik Abel. Uhlenbeck will receive the prize in Oslo on May 21.

[h/t New Scientist]

12 Intriguing Facts About the Intestines

When we talk about the belly, gut, or bowels, what we're really talking about are the intestines—long, hollow, coiled tubes that comprise a major part of the digestive tract, running from the stomach to the anus. The intestines begin with the small intestine, divided into three parts whimsically named the duodenum, jejunum, and ileum, which absorb most of the nutrients from what we eat and drink. Food then moves into the large intestine, or colon, which absorbs water from the digested food and expels it into the rectum. That's when sensitive nerves in your rectum create the sensation of needing to poop.

These organs can be the source of intestinal pain, such as in irritable bowel syndrome, but they can also support microbes that are beneficial to your overall health. Here are some more facts about your intestines.

1. The intestines were named by medieval anatomists.

Medieval anatomists had a pretty good understanding of the physiology of the gut, and are the ones who gave the intestinal sections their names, which are still used today in modern anatomy. When they weren't moralizing about the organs, they got metaphorical about them. In 1535, the Spanish doctor Andrés Laguna noted that because the intestines "carry the chyle and all the excrement through the entire region of the stomach as if through the Ocean Sea," they could be likened to "those tall ships which as soon as they have crossed the ocean come to Rouen with their cargoes on their way to Paris but transfer their cargoes at Rouen into small boats for the last stage of the journey up the Seine."

2. Leonardo da Vinci believed the intestines helped you breathe.

Leonardo mistakenly believed the digestive system aided respiratory function. In 1490, he wrote in his unpublished notebooks, "The compressed intestines with the condensed air which is generated in them, thrust the diaphragm upwards; the diaphragm compresses the lungs and expresses the air." While that isn't anatomically accurate, it is true that the opening of the lungs is helped by the relaxation of stomach muscles, which does draw down the diaphragm.

3. Your intestines could cover two tennis courts ...

Your intestines take up a whole lot of square footage inside you. "The surface area of the intestines, if laid out flat, would cover two tennis courts," Colby Zaph, a professor of immunology in the department of biochemistry and molecular biology at Melbourne's Monash University, tells Mental Floss. The small intestine alone is about 20 feet long, and the large intestine about 5 feet long.

4. ... and they're pretty athletic.

The process of moving food through your intestines requires a wave-like pattern of muscular action, known as peristalsis, which you can see in action during surgery in this YouTube video.

5. Your intestines can fold like a telescope—but that's not something you want to happen.

Intussusception is the name of a condition where a part of your intestine folds in on itself, usually between the lower part of the small intestine and the beginning of the large intestine. It often presents as severe intestinal pain and requires immediate medical attention. It's very rare, and in children may be related to a viral infection. In adults, it's more commonly a symptom of an abnormal growth or polyp.

6. Intestines are very discriminating.

"The intestines have to discriminate between good things—food, water, vitamins, good bacteria—and bad things, such as infectious organisms like viruses, parasites and bad bacteria," Zaph says. Researchers don't entirely know how the intestines do this. Zaph says that while your intestines are designed to keep dangerous bacteria contained, infectious microbes can sometimes penetrate your immune system through your intestines.

7. The small intestine is covered in "fingers" ...

The lining of the small intestine is blanketed in tiny finger-like protrusions known as villi. These villi are then covered in even tinier protrusions called microvilli, which help capture food particles to absorb nutrients, and move food on to the large intestine.

8. ... And you can't live without it.

Your small intestine "is the sole point of food and water absorption," Zaph says. Without it, "you'd have to be fed through the blood."

9. The intestines house your microbiome. 

The microbiome is made up of all kinds of microorganisms, including bacteria, viruses, fungi, and protozoans, "and probably used to include worm parasites too," says Zaph. So in a way, he adds, "we are constantly infected with something, but it [can be] helpful, not harmful."

10. Intestines are sensitive to change.

Zaph says that many factors change the composition of the microbiome, including antibiotics, foods we eat, stress, and infections. But in general, most people's microbiomes return to a stable state after these events. "The microbiome composition is different between people and affected by diseases. But we still don't know whether the different microbiomes cause disease, or are a result in the development of disease," he says.

11. Transferring bacteria from one gut to another can transfer disease—or maybe cure it.

"Studies in mice show that transplanting microbes from obese mice can transfer obesity to thin mice," Zaph says. But transplanting microbes from healthy people into sick people can be a powerful treatment for some intestinal infections, like that of the bacteria Clostridium difficile, he adds. Research is pouring out on how the microbiome affects various diseases, including multiple sclerosis, Parkinson's, and even autism.

12. The microbes in your intestines might influence how you respond to medical treatments.

Some people don't respond to cancer drugs as effectively as others, Zaph says. "One reason is that different microbiomes can metabolize the drugs differently." This has huge ramifications for chemotherapy and new cancer treatments called checkpoint inhibitors. As scientists learn more about how different bacteria metabolize drugs, they could possibly improve how effective existing cancer treatments are.

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