The enzymes in snot may help to change the chemical makeup of odors that enter the nose. Credit: ptaxa/iStock

Snot is often what shows up after a hard sneeze. It’s a constant companion of allergies and the common cold. It’s wet, sticky and — to most people — best left up the nose.

But snot, or mucus, also contains many different kinds of proteins. Those proteins may play an important role in something else that happens in the nose: smelling. In a recent study, researchers from Japan’s University of Tokyo showed that proteins in mucus change the makeup of odors before those scents even make it to smell receptors. Smell receptors are also proteins. They stick out from the cells that send signals about a smell to the brain, which identifies the odor.

That means that sticky, wet, gross mucus might have a more glamorous role: It may be important for smelling smells.

It seems natural to assume a connection between smells and snot. After all, the human nose is home to the sense of smell — and is an exit for snot. But “most people and most scientists pay no attention at all to mucus,” neuroscientist Leslie Vosshall told Science News. Vosshall is at Rockefeller University in New York City and was not involved in the recent study.

Scientists suspect that some molecules in mucus carry smells to other parts of the nose, where they can be detected. Other molecules in snot are enzymes, which start chemical reactions. Some enzymes may protect the body by chopping toxic substances — such as inhaled chemicals — into smaller, safer chunks. But until now, scientists did not know whether this chopping action could affect the smell of something.

To learn about smells and mucus, the researchers experimented on mice. They removed mucus from the noses of mice. Then, they mixed in chemicals that have particular odors. One of these chemicals was benzaldehyde, also known as artificial almond oil. After five minutes in mouse snot, the benzaldehyde had broken down into two chemicals — one that had no smell and another that did.

When the researchers inactivated the enzymes, by boiling the mucus, and then tried the same experiment again, the benzaldehyde did not break down.

That part of the experiment showed that the mucus could change the chemical composition of odors. Next, the researchers showed that the mice brains also register this difference. For this part of the project, the scientists “turned off” the mucus chemicals in the mice noses that usually chop up odorous molecules. As a result of this change, the mouse brains reacted differently than they did before — showing that their brains had picked up on the change.

The researchers also used mouse behavior to show that mucus changes the smell of something. For this part of the experiment, they used mice that had been trained to identify certain smells. (In training, the mice had been given treats when they went to those smells. After training, the mice naturally went back to those smells, hoping for more treats.) When the scientists turned off the important molecules in the mouse mucus, the mice were unable to recognize those favorite smells.

Scientists don’t know whether the molecules in mucus work the same way in people. Human mucus does have many of the same proteins as the mucus in mouse noses, so it’s worth investigating. Early studies do suggest that human snot can change odors, so stay tuned. And cover your nose when you sneeze.

POWER WORDS (adapted from the Yahoo! Kids Dictionary)

olfactory Of, relating to, or contributing to the sense of smell.

proteins Fundamental components of all living cells, including many substances, such as enzymes, hormones and antibodies, that are necessary for the proper functioning of an organism.

molecule A group of like or of different atoms held together by chemical forces.

enzyme Any of numerous proteins produced by living organisms that function as biochemical catalysts.

bacteria Single-celled microorganisms that vary in terms of morphology, oxygen and nutritional requirements, and motility. They may be free-living, saprophytic, or pathogenic in plants or animals.

Weird place on Earth Mono Lake in eastern California is where researchers found a type of bacteria that appears to break the rules for how we think life should survive. Credit: NASA image gallery

You may not know phosphorus when you see it, but your body does. Phosphorus is a sturdy workhorse element. In DNA molecules, phosphorus helps support the whole double helix. Within cells, energy shows up as ATP — and the “P” stands for phosphorus (specifically, phosphate, a form of phosphorus).

All life as we know it, in other words, depends on phosphorus. For that reason, scientists around the world were shocked December 2 when a team of scientists announced finding life forms that didn’t necessarily depend on this all-important element. In laboratory tests, the scientists grew bacteria that were able to use arsenic — a different element with similar chemistry — in the place of phosphorus.

It’s a surprising discovery because living organisms have never been found without all six of the ingredients crucial to life: carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur (all together known as CHNOPS). Arsenic, though, is a potentially fatal poison.

Many scientists say they would like to see more evidence that the research team did in fact observe life forms using arsenic instead of phosphorus.

“This is an amazing result, a striking, very important and astonishing result — if true,” Alan Schwartz told Science News. Schwartz researches chemistry at Radboud University Nijmegen in the Netherlands. “I’m even more skeptical than usual, because of the implications. But it is fascinating work.”

The bacteria came from Mono Lake, a lake in eastern California that is well known for its unusual population of living organisms, including shrimp and algae. The lake doesn’t drain, so the only way for water to leave is through evaporation. As a result, the lake is much saltier than the ocean.

An up-close picture of the bacteria GFAJ-1 grown on arsenic. Credit: Jodi Switzer Blum, NASA

Several researchers had been studying a number of tiny organisms that lived in Mono Lake mud. Astrobiologists study life in the universe and want to know how it started, how it has changed, and what will happen to life in the future. They also want to know whether life exists on other planets and if so, what it might look like. Many astrobiologists study what lives in Earth’s strangest places, such as Mono Lake, as a way to understand the possibilities for life.

The study was led by Felisa Wolfe-Simon of NASA’s Astrobiology Institute and the U.S. Geological Survey in Menlo Park, Calif. She and her team removed organisms from the Mono samples and grew those bacteria in the lab. The scientists fed the microbes with sugar and vitamins — but left out phosphate. Then they changed the diet again, and gave the microbes arsenate, which is a form of arsenic.

In one type of bacteria, called GFAJ-1, the researchers observed that arsenic wasn’t fatal. The bacteria continued to grow, though not as fast as if they’d had phosphorus. After studying these bacteria, Wolfe-Simon and her team concluded that the organisms had begun to make use of the arsenic the way they usually used phosphorus. The researchers suggest that arsenic was being used as a building block in the bacteria’s DNA.

“This microbe, if we are correct, has solved the challenge of being alive in a different way,” Wolfe-Simon told Science News.

If the scientists are right, then “life as we know it” may not include all the life that actually is possible. For astrobiologists, that conclusion suggests that life on other planets may not necessarily look like life on Earth.

It’s possible that follow-up studies will show that the researchers were mistaken. Wolfe-Simon and her team could not get rid of all the phosphorus when they were growing the bacteria. Some scientists say minute amounts might be enough to keep the microbes alive. It’s possible that, in the experiment, the bacterium GFAJ-1 was still getting small amounts of phosphate.

Can life exist using poison instead of phosphorus? Life of a different type is an exciting prospect, so stay tuned to see how the scientific community reacts. Next up, scientists will want to know how, exactly, the arsenic substitution works.

POWER WORDS

arsenic A highly poisonous metallic element having three allotropic forms, yellow, black and gray, of which the brittle, crystalline gray is the most common. Used in insecticides.

phosphorus A highly reactive, nonmetallic element occurring naturally in phosphates.

DNA A nucleic acid that carries the genetic information in the cell. DNA consists of two long chains of nucleotides twisted into a double helix and joined by hydrogen bonds between the bases.

molecule A group of like or of different atoms held together by chemical forces.

microbe A minute life form; a microorganism, especially a bacterium that causes disease.

bacterium A life form that is a single cell and too small to see without using a microscope. Bacteria (plural of bacterium) live in almost every environment on Earth, including very cold places, very warm places, in all types of water, in the air, even on and in plants and animals. These microorganisms can also cause disease in plants and animals.

This image represents the evolution of the universe over its 13.7 billion years. Time increases from left to right, starting from the period of inflation to the present day. Source: WMAP team/NASA

How old is the universe? Ask a cosmologist, and you’ll probably learn that the universe was born with the Big Bang about 13.7 billion years ago. (Cosmologists study the age of the universe.) At the time of the Big Bang, the universe, then smaller than an atom, started to get big — very quickly. It’s been growing ever since.

But if you ask Roger Penrose and Vahe Gurzadyan, you’ll get a much different — and wilder — answer. They’ll agree that the Big Bang probably happened 13.7 billion years ago, but they might argue that it was not the beginning. In a new, online paper by Penrose and Gurzadyan, the scientists suggest that the Big Bang was only the latest in a series of many “bangs.” The universe, in other words, has had many births — and many deaths.

If they’re right, the Big Bang is actually just the latest “bang,” and the universe has expanded and contracted multiple times.

Here’s a way to understand their theory. Imagine that the universe started out as a lump of uncooked bread dough. Just as bread dough grows with time (if you let it rise), the universe has been expanding ever since the Big Bang.

If the universe is bread dough in the model of Penrose and Gurzadyan, the dough doesn’t act like anything you’ve ever kneaded. Instead, this dough rises, and then falls. And then rises again. Then falls again.

The WMAP picture of the universe as it appeared 13.7 years ago is a major tool cosmologists use to understand the universe’s earliest time. WMAP stands for Wilkinson Microwave Anisotropy Probe, because this background radiation from the early universe is “visible” in microwave energy. Source: WMAP team/NASA

Penrose is a theoretical physicist at the University of Oxford in England. Gurzadyan is a physicist at the Yerevan Physics Institute and Yerevan State University in Armenia.

Penrose is famous for his accomplishments in physics and mathematics, including research on how black holes emerge from the deaths of stars. His best-selling books explain complicated science topics to ordinary readers. He is also famous, however, for saying that popular ideas in physics are just plain wrong.

Penrose and Gurzadyan claim that the evidence for their idea lies in a map of the early universe. This isn’t any ordinary map. It doesn’t show only constellations or galaxies. Instead, it shows the oldest light in the universe, left over from the Big Bang. This light isn’t visible. It’s microwave radiation, and it is like a fading glimpse of the first moment in time.

After studying the data, the physicists say they’ve found strange patterns in the map. In some places, the microwave radiation looks a little different from the rest of the picture. In the map, these regions look like circles within circles — they’re places where the radiation temperatures are unlike those in other parts of the universe, but in a weird way.

In general, the background radiation looks like a mess — there are many different spots of different temperatures right next to each other. But within the circles, the temperature isn’t messed up enough. In other words, some natural force caused these regions to be too tidy.

Two physicists say a pattern of concentric circles in the map holds new information about the universe’s beginning. Source: V.G.Gurzadyan and R.Penrose

Penrose and Gurzadyan say these circles can’t be explained by the theory of inflation, which says the universe expanded very rapidly right after the Big Bang.

Their idea for how the circles showed up is wild. In the previous version of the universe, they argue, supermassive black holes might have collided. This giant smash-up would have produced powerful waves that moved away from the collision in concentric circles. These waves are called gravitational waves, and they shake the very fabric of the universe.

Penrose and Gurzadyan say that when the previous universe ended and ours began, those gravitational waves turned into energy. That extra energy burst created the tidy concentric circles that the physicists found.

In other words, those concentric circles are like echoes of black holes that smashed together — in a previous universe.

It’s a wild idea, and not all physicists are ready to get behind Penrose and Gurzadyan. After all, their work seems to cast doubt on inflation, one of the most important ideas in modern cosmology. To convince their colleagues, Penrose and Gurzadyan still have a lot of work to do.

“The paper does not provide enough detail about the analysis to assess the reality of these circles,” David Spergel told Science News. Spergel is a cosmologist at Princeton University.

POWER WORDS (adapted from NASA and the Yahoo! Kids Dictionary)

Big Bang The cosmic expansion that marked the origin of the universe, according to current theory.

cosmology The study of the history, structure and movements of the universe.

inflation theory A theory that proposes a period of extremely rapid expansion of the universe during its first few moments.

cosmic microwave radiation background The heat left over from the Big Bang and that should exist throughout the universe. It is estimated to be about 2.725 degrees above absolute zero.

Lake Tahoe, seen here from Emerald Bay, was one of the 167 major lakes studied. Credit: Jet Propulsion Laboratory, NASA

There’s no doubt: In the last few decades, the average temperature on Earth has been higher than it’s been in hundreds of years. Around the world, people are starting to measure the effects of global warming — and trying to figure out what to do about it.

Scientists recently used satellites to study the temperatures of lakes around the world, and they found that lakes are heating up. Between 1985 and 2009, satellites recorded the nighttime temperatures of the surfaces of 167 lakes. During those 24 years, the lakes got warmer — by an average of about 0.045 degree Celsius per year.

In some places, lakes have been warming by as much as 0.10 degree Celsius per year. At that rate, a lake may warm by a full degree Celsius, or 1.8 degrees Fahrenheit, in just 10 years. That difference may seem small — you might not even notice it in your bathtub. But in a lake, slightly warmer temperatures could mean more algae, and algae can make the lake poisonous to fish.

The scientists who did the study work for NASA’s Jet Propulsion Laboratory at the California Institute of Technology in Pasadena. They report that lakes seem to be warming faster in the northern parts of the Northern Hemisphere. In the United States, lakes in the southwestern part of the country warmed faster than did the Great Lakes in the north.

The study shows that in some regions, lakes are warming faster than the air around them. This is important because scientists often use measurements of air temperature to study how the Earth is warming. By using lake temperatures as well, scientists can get a better picture of global warming. The scientists say data on lakes give scientists a new way to measure the impact of climate change around the world.

This is an Advanced Along-Track Scanning Radiometer (AATSR) image of the Lake Tahoe region, acquired September 25, 2002. It’s the type of satellite data used to compute lake surface temperatures. Source: Jet Propulsion Laboratory, NASA

That’s going to be useful, since no country is too big or too small to ignore climate change. Scientists aren’t the only ones concerned. Everyone who lives on Earth is going to be affected by the rapid warming of the planet. Many world leaders believe we might be able to do something about it, especially by reducing the amount of greenhouse gases we put into the air.

That’s why the United Nations started the Framework Convention on Climate Change, or UNFCCC. Every year the convention meets, and representatives from countries around the world gather to talk about climate change and discuss global solutions to the challenges of a warming world. This year, convention members will also discuss progress on the Kyoto Protocol, a plan to get the world’s largest polluters to reduce global greenhouse gas emissions. This year’s meeting began November 29 in Cancún, Mexico, and ends December 10.

“Climate change is humanity’s long-term challenge,” Christiana Figueres told the audience on the first day of the conference. Figueres is the executive secretary of the UNFCCC. “Cancún will be successful if parties compromise, if they make sure that in the process of getting what they want they allow others to leave with what they need.”

The President of Mexico, Felipe Calderón, also spoke on the opening day. He said we are already seeing the devastating effects of climate change, including recent storms and hurricanes in Mexico, flooding in Pakistan and devastating fires in Russia. It is important to do something, he said, for the sake of our children, and of their children.

“Climate change is an issue that affects life on a planetary scale,” Calderón said.

POWER WORDS (adapted from the Yahoo! Kids Dictionary)

global warming An increase in the average temperature of Earth’s atmosphere, especially a sustained increase sufficient to cause climatic change.

greenhouse gas Any of the atmospheric gases that contribute to the greenhouse effect.

satellite An object launched to orbit Earth or another celestial body.