Biologist Dorothy Matthews and company wanted to test a particular bacteria, Mycobacterium vaccae. It’s found commonly in the soil and carried widely through the air, so if you take a walk in the park you’ll probably breathe it in. Previous studies have shown that the bacterium increases serotonin in the brain, and have even suggested that the bacterium has antidepressant qualities. Since the neurotransmitter serotonin is also involved in cognition, the team wanted to see if the bacterium could have a direct effect on learning. Indeed it did, Matthews’ team announced at the General Meeting of the American Society for Microbiology in San Diego.
In a classic test of learning ability, Matthews gave mice a treat – white bread with peanut butter – as a reward to encourage them to learn to run through a maze. When she laced the treat with a tiny bit of Mycobacterium vaccae, she found that the mice ran through the maze twice as fast as mice that were given plain peanut butter [New Scientist].
Kaleidoscopic. Delightfully odd. And too numerous to truly grasp.
There are many more words one could deploy to describe the worlds unknown under the sea. An international group of scientists has been scouring them for life for the last decade, and later this year, on October 4, the Census of Marine Life will release it catalog of marine inhabitants. “The number could be astonishingly large, perhaps a million or more, if all small animals and protists are included,” the organization says.
Octopuses, jellyfish, and other sprawling sea creatures dominated the census’ prior reports. But this time they’ve dived even deeper, surveying tiny life. Remotely operated deep-sea vehicles discovered that roundworms dominate the deepest, darkest abyss. Sometimes, more than 500,000 can exist in just over a square yard of soft clay [AP].
And then there are the microbes. The scientists conservatively estimate that there must be at least 20 million kinds of microbe in the oceans. The true number may even be billions or trillions [Nature]. Individual microbes reach even more astronomical number. There are probably a nonillion of them in the sea, the scientists estimate. That’s a billion cubed, and then times 1,000. Or, if you prefer your measurements given in the weight of African elephants, it’d be 240 billion of them.
Take a peek through this quick slideshow of some of the weirdest ocean life seen so far.
Here’s a new way to prove the maxim that we are what we eat: Take a peek into the teeming universe of bacteria that thrive in a Japanese person’s gut. Trillions of microbes in the gut help digest the foods we eat, and researchers have found that the “gut microbiomes” of Japanese people have adapted over the centuries to help digest seaweed–an integral part of sushi. Remarkably, they adapted by taking in genetic material found in that very sushi.
The new study, published in Nature, reveals that these gut bacteria engaged in a gene swap, grabbing algae-digesting genes from marine bacteria that live on red algae like nori, the seaweed used to wrap sushi. The marine bacteria traveled on the seaweed into human digestive systems, where the crucial genes were transferred to bacteria in the gut.
Scientists stumbled on this swap when they identified a new group of enzymes from the algae-chomping marine bacteria that help the microbes break down the unique carbohydrates in seaweed. When they searched for other organisms that had the same enzymes, they found one match that, oddly, came from a species of bacteria that lived in the gut of a Japanese volunteer. Further study revealed that this species of gut bacteria is seen only in Japanese individuals.
If you thought that fingerprints or DNA fragments were the only bits of forensic evidence that could pin you to a scene of a crime, then think again. Researchers at the University of Colorado, Boulder have found preliminary evidence suggesting that you can be identified from the unique mix of bacteria that lives on you.
Each person, they say, is a teeming petri dish of bacteria, but the composition varies from person to person. Every place a person goes and each thing he touches is smudged with his unique “microbial fingerprint.” The bacterial mixes are so specific to individuals that researchers found that they could pair up individual computer keyboards with their owners–just by matching the bacteria found on the keyboard to the bacteria found on the person’s fingertips. Describing their findings in the journal Proceedings of the National Academy of Sciences, scientists write that that if this bacterial fingerprint technique is refined, it could one day help in forensic investigations.
The Human Microbiome Project has already found that different body parts harbor different kinds of microbes. Study coauthors Noah Fierer and Rob Knight note that these colonies don’t change much over time. No amount of hand-washing will change a person’s microbial make-up, they say.
The human genome may have been sequenced back in 2004, but that was a far cry from documenting all the genes inside us. Our bodies are home to a dizzying number and variety of bacteria, and in a study published in this week’s Nature, researchers have used metagenomic sequencing to catalog the genes that belong to the microbes living in our guts.
The project, which sampled 124 European people, found that each individual had at least 160 species of bacteria living in his or her digestive tract, and there’s a lot of overlap between our guts. At least 57 species of bacteria were present in just about everybody. Overall, the researchers cataloged about 1,000 different bacteria species and figure there’s another 150 or so they haven’t found [AP].
Once again, laziness pays off. When microbiologist Lars Peter Nielsen and his team were studying marine sediments, they got a little sloppy about cleaning their beakers. But after letting samples sit around in the lab for a few weeks, they began to see weird chemical patterns in them that you just wouldn’t expect. As they saw changes in the surface of the mud quickly trigger other changes down below, the scientists came upon a startling idea: that the bacteria in the top layer and those deep down were somehow electrically linked. Their paper appears this week in Nature.
Specifically, Nielsen saw that hydrogen sulfide buried below the sediment’s surface (the stuff that makes it smell bad) was oxidizing and changing color. One problem, though: That shouldn’t be happening. Below the sediment surface there is plenty of hydrogen sulfide and carbon for bacteria to consume via oxidation, or removing electrons [Scientific American]. But the reaction can’t be sustained without access to dissolved oxygen, which carries away electrons produced by the reaction, and in these samples the oxygen was all up at the sediment’s surface. So the researchers hypothesize that the buried bacteria form a conductive chain to ferry the electrons up to the surface.
Most of us associate the bacteria E. coli with nasty stomach ailments. But a new study published in Naturemagazinesuggests E. coli can not just turn stomachs, but could potentially turn the wheels of your car, since a genetically engineered strain of the bacteria has produced clean, road-ready biodiesel.
The bacteria can work on any type of biomass, including wood chip, switchgrass, and the plant parts that are left behind after a harvest–all contain cellulose, a structural material that comprises much of a plant’s mass. Study coauthor Jay Keasling and his colleagues report engineering E. coli bacteria to synthesize and excrete the enzyme hemicellulase, which breaks down cellulose into sugars. The bacteria can then convert those sugars into a variety of chemicals–diesel fuel among them. The final products are excreted by the bacteria and then float to the top of the fermentation vat before being siphoned off [Technology Review].
One small step for flashing bacteria, one giant leap for synthetic biology. In a new Naturestudy, molecular biologist Jeff Hasty and his team say they have created a line of E. coli bacteria that flash in fluorescent light and keep time like a clock.
Previously, scientists had engineered only single cells to become oscillators — devices that could count time by performing a particular activity on a cyclical schedule [Nature News]. Back in 2008, Hasty and his team created an oscillator for single cells that could be set to temperature or chemical triggers. But now the researchers have induced a whole host of bacteria to work together to keep time by taking advantage of the way they collaborate naturally: quorom sensing.
Breaking news from the “Great–one more thing to worry about” file! Microbiologists have looked inside showerheads and found that the dark and damp crannies provide perfect conditions for the growth of bacterial film. A new study in the Proceedings of the National Academy of Sciences looked at showerheads in nine cities and found that they harbor colonies of Mycobacterium avium in particular, a type of microbe that can cause lung ailments. “If you are getting a face full of water when you first turn your shower on, that means you are probably getting a particularly high load of Mycobacterium avium, which may not be too healthy,” says lead author Norman Pace [CNET].
These findings may sound alarming, but the researchers stress that bacteria is everywhere–in the air we breathe and the water we drink–and for the most part, these microbes pose little danger. Study coauthor Leah Feazel says of the shower findings: “This really shouldn’t concern average, healthy people. The main concern is for people who are immune-compromised” [Reuters]. People with AIDS or other immune system disorders should consider getting metal showerheads, which harbor less bacteria than plastic, and changing them often. Anybody else who feels uncomfortable with the idea of a bacterial shower has a couple of options–they can let the shower run for 30 seconds or so before stepping in to flush out some of the microbes, or they can take a bath.
One of the greatest musical geniuses the world has ever seen might have been struck down at the height of his powers by a bacterial infection that school nurses yawn at. A new analysis suggests that Wolfgang Amadeus Mozart may have died of complications relating to strep throat.
Mozart died on December 5, 1791 in Vienna after abruptly taking ill about two weeks before. The cause of death for the 35-year-old man was recorded as “fever and rash,” which even in the 18th century were considered symptoms, not a disease. Many causes have been suggested over the centuries: syphilis, the effects of treatment with salts of mercury, rheumatic fever, vasculitis leading to renal failure, infection from a bloodletting procedure, trichinosis from eating undercooked pork chops [The New York Times]. As no autopsy was conducted at the time of death and the common grave that held Mozart’s remains was later dug up to make room for new graves, modern medical sleuths have little direct evidence to go on.
A new study of the atmosphere of Mars casts doubt on the enticing possibility that methane plumes emanating from the planet are a signature of microbial life. The researchers found that the variations in methane concentration across Mars could only be explained if the methane produced was quickly broken down by unknown forces, before atmospheric currents could distribute the gas evenly around the planet. But methane is the simplest organic molecule, so if something is destroying it, then other, more complex organic molecules could suffer the same fate [New Scientist].
The mystery began in 2003, when scientists first detected plumes of methane coming from the Martian surface; further observations revealed that the hotspots varied with the Martian seasons. Researchers said the methane could come from volcanic activity, but said it could also, theoretically, be the gaseous excretions of bacteria buried deep underground. To probe the mystery, researchers used a model of the Martian climate that accounted for the chemistry of the atmosphere and its wind patterns, and studied whether the planet’s conditions would allow for the isolated bursts of methane that researchers had previously observed.
To stop the spread of the Sahara Desert, one innovative thinker has proposed a bold plan: a wall along the southern border of the desert that would hold back the advancing dunes. Swedish architect Magnus Larsson says the wall would effectively be made by “freezing” the shifting sand dunes, turning them into sandstone. “The idea is to stop the desert using the desert itself,” he said. The sand grains would be bound together using a bacterium called Bacillus pasteurii commonly found in wetlands.” It is a microorganism which chemically produces calcite – a kind of natural cement” [BBC News].
Larsson is already well-known in the field thanks to his proposed Great Green Wall, a 4,349 mile line of trees stretching across Africa to stop desertification [Fast Company]. The sandstone wall could compliment the green wall, Larsson says, because if people chopped down the trees for firewood the sandstone wall would still remain.
After 120,000 years of slumbering in a Greenland glacier beneath almost two miles of ice, an ultra-small bacteria has been resurrected by the patient efforts of scientists. After incubating the bacteria for almost a year in water that was just above freezing temperature, colonies of the tiny purple-brown bacteria began to grow in a petri dish. Researchers say the bacteria’s resilience provides clues to how life can survive in hostile environments like the Arctic–and maybe even other planets.
The Herminiimonas glaciei bug is not the oldest to ever be resurrected, but it’s the first “ultramicrobacteria” to be revived. Ultramicrobacteria, tiny even by bacterial standards, are about 10 to 50 times smaller than the common human intestinal microbe E. coli. Their diminutive size could give the bacteria a survival advantage over other microorganisms. H. glaciei, for example, is thought to have survived in thin capillaries of nutrient-rich water in the Greenland glacier that would have been too tight a fit for larger bacteria [National Geographic News].
It’s not just humans who can take part in combating global warming–cows can play a role, too. Scientists say that the methane belched up by cows is a significant source of the greenhouse gas, and are searching for ways to reduce these burps. The digestive bacteria in the cows’ stomach produces the methane, which is the second-most significant gas (behind carbon dioxide) driving global warming. While methane is much less prevalent in the atmosphere than carbon dioxide, it traps heat 20 times more efficiently than carbon dioxide.
Researchers are examining a variety of tactics, including breeding or genetically engineering cows that belch less, or adjusting the bacterial mix in cows’ stomachs. But altering the cows’ feed has shown the most promise thus far. Since January, cows at 15 farms across Vermont have had their grain feed adjusted to include more plants like alfalfa and flaxseed — substances that, unlike corn or soy, mimic the spring grasses that the animals evolved long ago to eat. As of the last reading in mid-May, the methane output of [one test] herd had dropped 18 percent. Meanwhile, milk production has held its own [The New York Times].
Hydrogen peroxide can kill viruses and bacteria, and it’s been used for generations to sterilize wounds and help them heal faster. But a new study published in the journal Nature shows that the substance may also serve as a Pied Piper for white blood cells, summoning them to the site of a wound to promote healing.
Damaged tissue hails a variety of cells to defend the body from infectious agents; one type is white blood cells, which kill by initiating a “respiratory burst,” which releases highly reactive antimicrobial molecules, including hydrogen peroxide produced by the body itself [ScienceNOW Daily News]. But it wasn’t until now that researchers noticed that hydrogen peroxide appeared at the injury site an average of 17 minutes before the immune cells arrived. Study coauthor Phillipp Niethammer explains that after nicking the tail of a zebrafish, “I saw something bursting at the wound,” he says, “but I didn’t see leukocytes there.” That bursting, experiments revealed, was hydrogen peroxide… [I]t appeared as if hydrogen peroxide was bringing leukocytes to the wound rather than the other way around [ScienceNOW Daily News]. Further investigations revealed more about the chain of post-injury events.
80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles on the day's most compelling topics.
80beats is written by Veronique Greenwood and Valerie Ross. This team darts through each day's science news faster than the ruby-throated hummingbird that beats its wings 80 times per second. Send ideas, tips, suggestions, and complaints to [azeeberg at discovermagazine dot com].
This is not an “eat dirt for your health and happiness” study. You don’t need to shovel soil in your mouth. Just go outside.
Here’s a new way to prove the maxim that we are what we eat: Take a peek into the teeming universe of bacteria that thrive in a Japanese person’s gut. Trillions of microbes in the gut help digest the foods we eat, and researchers have found that the “gut microbiomes” of Japanese people have adapted over the centuries to help digest seaweed–an integral part of sushi. Remarkably, they adapted by taking in genetic material found in that very sushi.
If you thought that fingerprints or DNA fragments were the only bits of forensic evidence that could pin you to a scene of a crime, then think again. Researchers at the 
The human genome may have been sequenced back in 2004, but that was a far cry from documenting all the genes inside us. Our bodies are home to a dizzying number and variety of bacteria, and in a 
Once again, laziness pays off. When microbiologist Lars Peter Nielsen and his team were studying marine sediments, they got a little sloppy about cleaning their beakers. But after letting samples sit around in the lab for a few weeks, they began to see weird chemical patterns in them that you just wouldn’t expect. As they saw changes in the surface of the mud quickly trigger other changes down below, the scientists came upon a startling idea: that the bacteria in the top layer and those deep down were somehow electrically linked. Their 
Most of us associate the bacteria E. coli with nasty stomach ailments. But a new
Breaking news from the “Great–one more thing to worry about” file! Microbiologists have looked inside showerheads and found that the dark and damp crannies provide perfect conditions for the growth of 
One of the greatest 
A new study of the atmosphere of 
To stop the spread of the Sahara Desert, one innovative thinker has proposed a bold plan: a wall along the southern border of the 
After 120,000 years of slumbering in a Greenland 
It’s not just humans who can take part in combating 
Hydrogen peroxide can kill 
