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.
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Image: flickr / stevendepolo
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.
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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.
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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.
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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].
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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].
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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.
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Researchers are singing a song of praise for armpits, groins, and all the other moist parts of the body that polite society prefers not to contemplate.
On the microbial level, a person’s underarms are akin to lush rain forests brimming with diversity—and that’s a good thing—according to a new “topographic map” of human skin. Most of our skin is like an arid desert, said study co-author Julia Segre… “But as you walk through this desert you encounter an oasis, which is the inside of your nose,” she said. “You encounter a stream, which is a moist crease. [These] areas are like habitats rich in diversity” [National Geographic News]. In the new study, the researchers cataloged the bacteria distributed across human skin, and note that a better understanding of these native bacteria of the epidermis may help doctors promote skin health and fight skin diseases.
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The disease of leprosy has been eating away at humankind for the past 4,000 years, according to a newly discovered skeleton that showed signs of the ailment. Researchers say that the ancient leper provides clues to how the disease spread through the human population. The skeleton was found at the site of Balathal, near Udaipur in northwestern India. Historians have long considered the Indian subcontinent to be the source of the leprosy that was first reported in Europe in the fourth century B.C., shortly after the armies of Alexander the Great returned from India [The New York Times].
The skeleton was buried, which is uncommon in the Hindu tradition unless the person is highly respected or unfit to be cremated, a category that included outcasts, pregnant women, children under 5, victims of magic or curses, and lepers. The leper’s skeleton was interred within a large stone enclosure that had been filled with vitrified ash from burned cow dung, the most sacred and purifying of substances in Vedic tradition [LiveScience]. A close examination of the skull showed eroded pits typical of advanced leprosy, as well as tooth loss and root exposure.
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When the liver of a live mouse began to glow with infrared light, researchers knew they’d gotten it right. In a new study, biochemists developed an imaging technique that will allow scientists to get an unprecedented look at biological processes going on in real time, and within the body of an animal rather than inside a petri dish.
The new technology builds on earlier work with fluorescence. Fluorescent proteins, which are compounds that can absorb and then emit light, have become a powerful instrument in the cell biologist’s toolkit—so powerful, in fact, that the discovery and development of green fluorescent proteins from jellyfish earned the 2008 Nobel Prize in Chemistry [Scientific American]. But although these green fluorescent proteins have become an indispensable tool in biological research, functioning as glowing markers of particular cells or proteins, the technology has its limits. The wavelengths of light it emits and light used to observe this emission are quickly absorbed by cells, making it difficult to study living cells except in laboratory tissue cultures, microbes and extremely tiny animals [Wired].
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Life sure turns up in the darnedest places. The latest discovery comes from Blood Falls, a rusty red discolouration on the face of the Taylor Glacier in Antarctica [that] occasionally gushes forth a transparent, briny, iron-rich liquid that quickly oxidizes and turns red, staining the ice below [Nature News].
The source of that water is an intensely salty lake trapped beneath 1,300 feet of ice, and a new study has now found that microbes have carved out a niche for themselves in that inhospitable environment, living on sulfur and iron compounds. The bacteria colony has been isolated there for about 1.5 million years, researchers say, ever since the glacier rolled over the lake and created a cold, dark, oxygen-poor ecosystem.
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About 2.7 billion years ago, the primordial seas already hosted the first photosynthetic microbes, the blue-green algae that took in carbon dioxide and released oxygen into the air. But they were outnumbered by methane-producing bacteria called methanogens [that] thrived in nickel-rich seas. The high amounts of methane that this early life pumped into the environment prevented oxygen accumulation in the atmosphere because the methane reacted with any oxygen, creating carbon dioxide and water [Science News], according to one theory. Now, a group of researchers say they’ve found the trigger that allowed oxygen to build up, and therefore allowed for a profusion of oxygen-breathing life.
The secret was the concentrations of the metal nickel, according to the new study, published in Nature. The scientists found that by analysing a type of sedimentary rock known as banded-iron formations they could monitor levels of nickel in the oceans of the early Earth dating as far back as 3.8 billion years ago. They found there was a marked fall in nickel between 2.7 billion and 2.5 billion years ago [The Independent]. That stretch of time correlates with what researchers call the Great Oxidation Event, when oxygen began to take hold in the atmosphere.
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NASA has proposed sending both an orbiter and a robotic explorer to Mars in the next decade to follow up on the recent report that Mars “hotspots” emit plumes of methane gas, which could be produced by either geothermal reactions or by deeply buried bacteria that breathe out methane as a waste product. That exciting phenomenon, which is still being debated by Mars experts, was observed by researchers using ground-based telescopes to measure seasonal fluctuations of gases on the planet. Researchers say closer observations would have a much better chance of determining whether the methane does signal the ultimate prize: extraterrestrial life.
NASA officials sketched out their proposal at a meeting of Mars scientists, but stressed that plans could change. The current idea is to launch the Mars Science Orbiter in 2016 followed by a exobiology lander or rover mission launched during a particularly juicy launch window in 2018 (the best since the Spirit and Opportunity rovers)…. The plan would also follow a natural progression: MSO would map the methane; the lander or rover would go after it with a suite of astrobiological instruments [Nature blog].
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The spit in each person’s mouth contains a diverse and unique universe of bacteria, according to a study in the journal Genome Research, and there’s no geographical pattern to the differences between one mouth and the next. A new worldwide survey of the human saliva microbiome – the bugs in our spit – finds that a man from La Paz, Bolivia, shares no more microbes in common with his neighbours than with a woman from Shanghai [New Scientist].
Molecular anthropologist Mark Stoneking made the discovery while searching for a better way to trace prehistoric human migrations. He had been impressed by how anthropologists were able to trace human migrations through the differences in the strains of the stomach bug Helicobacter pylori in various groups of people…. “With that species, you see very strong geographic patterning,” says Stoneking. But getting a sample of H. pylori is relatively difficult, as it requires a stomach biopsy. He wondered whether any of the bacteria in spit would work instead [ScienceNOW Daily News].
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The biodefense lab that was associated with the anthrax mailings of 2001 is temporarily shutting down most research to allow officials to make a thorough accounting of every germ, virus, and poison that’s being stored at the facility. The lab, at Fort Detrick in Maryland, has come under intense scrutiny since the FBI accused researcher Bruce Ivins of sending the 2001 letters laced with anthrax. (Ivins killed himself while under investigation.) Now, officials want to comb through storage rooms and refrigerators to ensure that every dangerous agent is listed in the lab’s inventory. The suspension started Friday, and the tedious process of counting thousands of vials could take up to three months, institute spokeswoman Caree Vander Linden said [AP].
The order to stop most work came after a spot check last month found 20 samples of Venezuelan equine encephalitis in a box of vials instead of the 16 that had been listed in the institute’s database [Washington Post], officials say. “I believe that the probability that there are additional vials of BSAT [biological select agents and toxins] not captured in our … database is high,” Skvorak wrote in a memo to employees [ScienceInsider]. Researchers at the lab work with some of the most dangerous infectious diseases known, like anthrax and Ebola, but officials stressed that they do not know of any missing vials of lethal substances.
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