Archive for the ‘Bacteria’ Category

A student in Taiwan who kept a pair of disposable contact lenses in her eyes for six months has been left blinded after a microscopic bug devoured her eyeballs.

The tiny single-cell amoeba ate away at undergraduate Lian Kao’s sight because she didn’t take out and clean the contacts once during that time.

According to a warning issued by doctors the case was a particularly severe example of a young person under pressure who did not take the time to carry out basic hygiene on their contact lenses

As well as being regularly cleaned, contact lenses should also be removed when swimming and washing.

The general advice is to avoid wearing contacts for more than eight hours a day.

Yet apparently 23-year-old Kao had even kept her contact lenses in at all times, even at the swimming pool.

Medics were horrified when they removed the contact lenses to find that the surface of the girl’s eyes had literally been eaten by the amoeba that had been able to breed in the perfect conditions that existed between the contact lens and the eye.

The director of ophthalmology at Taipei’s Wan Fang Hospital, Wu Jian-liang, said: ‘Contact lens wearers are a high-risk group that can easily be exposed to eye diseases.

‘A shortage of oxygen can destroy the surface of the epithelial tissue, creating tiny wounds into which the bacteria can easily infect, spreading to the rest of the eye and providing a perfect breeding ground.

‘The girl should have thrown the contact lenses away after a month but instead she overused them and has now permanently damaged her corneas.’

He said that she had been diagnosed with acanthamoeba keratitis, which although rare was always more common in the summer.

He confirmed and spoke about the girl’s case as a way of urging others to be more careful if they had to use contact lenses.

The problem is the condition can build up over several years – it’s only when it gets to an advanced stage that contacts wearers become aware of a problem, as that’s when it will cause red, irritated eyes, by which time it may be too late.

Acanthamoeba bugs stick to contact lenses and can then burrow their way through the cornea, causing acute pain.

It’s only at this stage that a sufferer would be aware they had a problem.

Prescription drugs may be able to treat the bug in the early stages, but specialists say it is very difficult to get rid of. In serious cases, the patient needs a corneal transplant but these have a high failure rate, resulting in sight loss.

Other steps to prevent the infection include never swimming or using a hot tub or shower when wearing contacts.

Each year, infections cause around 6,000 cases of a severe eye condition known as microbial keratitis – inflammation and ulceration of the cornea that can lead to vision loss.

Contact lens wearers are at a higher risk, since bacteria can get trapped in the lenses.

Read more: http://www.dailymail.co.uk/news/article-2687477/Student-goes-blind-keeping-contact-lenses-six-months-microscopic-bug-EATS-eyeballs.html#ixzz37dnGxTKv

Thanks to Pete Cuomo for bringing this to the attention of the It’s Interesting community.

Advertisements

The NASA Curiosity rover that was thought to bring only cameras, sensors, and scientific equipment when it traveled to Mars in August 2012 may have brought along dozens of species of bacteria that originated on Earth, according to a new study.

A study conducted by the American Society for Microbiology and published in the Nature science journal revealed that 377 strains of bacteria may have survived the sterilization process that the Curiosity rover endured before it was launched in an attempt to avoid contaminating the red planet.

It was less of a surprise for scientists that the bacteria survived the cleaning process than the revelation about the conditions they went through. The microbes in question endured near-freezing temperatures and intense damage caused by ultra-C radiation, thought to be the most harmful type of radiation.

“Although studies are constantly expanding our knowledge about life in extreme environments, it is still unclear whether organisms from Earth can survive and grow in a Martian environment where there is intense radiation, high oxidation potential, extreme desiccation, and limited nutrients,” microbiologist Stephanie Smith of the University of Idaho in Moscow and lead author of the study wrote in the study’s abstract.

“Knowing if microorganisms survive in conditions simulating those on the Martian surface is paramount to addressing whether these microorganisms could pose a risk to future challenging planetary protection missions.”

Whether the bacteria spread to the Mars surface is unknown, although the very possibility has already made scientists concerned about unnaturally spreading life from earth to Mars.

There is already a United Nations Outer Space Treaty that aims to regulate how the increasingly advanced space programs from the international community explore the unknown. The parameters were first agreed upon in 1966 and they include, among others, the stipulation that “States shall be liable for damage caused by their space objects; and shall avoid harmful contamination of space and celestial bodies.”

The limits vary depending on where the spacecraft lands. Mars, Europa, and other bodies that could potentially nurture life have a relatively strict standard of 300 bacterial spores per square meter. The goal is to keep the odds of contamination Mars (and others) at less than 1 in 10,000.

“Up to 300,000 spores are allowed on the exposed surfaces of the landed spacecraft. That many spores would fit on the head of a large pin,” said Laura Newlin, an engineer at NASA’s Jet Propulsion Laboratory in California. “Currently our total spore count on the surface…is comfortably under 200,000, so we’re below the allowable level.”

The announcement comes at a time when another team of researchers published an unrelated study revealing that methanogens, the oldest organisms on earth, could be the perfect candidate to foster Martian life. The University of Arkansas Fayetteville study determined that, because methanogens are non-photosynthetic and capable of living without oxygen, they are capable of living underground on Mars.

“The surface temperature of Mars varies widely, often ranging between minus 90 degrees Celsius and 27 degrees Celsius over one Martian day,” Rebecca Mickol, a doctoral student of space and planetary sciences, told Science Daily. “If any life were to exist on Mars right now, it would have to at least survive that temperature range. The survival of these two methanogen species, exposed to long-term freeze thaw cycles, suggests methanogens could potentially inhabit the future of Mars.”

http://rt.com/usa/160636-mars-curiosity-rover-bacteria/

heart infection

University of Iowa researchers have discovered what causes the lethal effects of staphylococcal infective endocarditis – a serious bacterial infection of heart valves that kills approximately 20,000 Americans each year. According to the UI study, the culprits are superantigens — toxins produced in large quantities by Staphylococcus aureus bacteria — which disrupt the immune system, turning it from friend to foe.

“The function of a superantigen is to ‘mess’ with the immune system,” says Patrick Schlievert, PhD, UI professor and chair of microbiology at the UI Carver College of Medicine. “Our study shows that in endocarditis, a superantigen is over-activating the immune system, and the excessive immune response is actually contributing very significantly to the destructive aspects of the disease, including capillary leakage, low blood pressure, shock, fever, destruction of the heart valves, and strokes that may occur in half of patients.”

Other superantigens include toxic shock syndrome toxin-1, which Schlievert identified in 1981 as the cause of toxic shock syndrome.

Staph bacteria is the most significant cause of serious infectious diseases in the United States, according to the Centers for Disease Control and Prevention (CDC), and infective endocarditis is the most serious complication of staph bloodstream infection. This dangerous condition affects approximately 40,000 people annually and has a death rate of about 50 percent. Among patients who survive the infection, approximately half will have a stroke due to the damage from the aggressive infection of the heart valves.

Despite the serious nature of this disease, little progress has been made over the past several decades in treating the deadly condition.

The new study, led Schlievert, and published Aug. 20 in the online open-access journal mBio, suggests that blocking the action of superantigens might provide a new approach for treating infective endocarditis.

“We have high affinity molecules that neutralize superantigens and we have previously shown in experimental animals that we can actually prevent strokes associated with endocarditis in animal models. Likewise, we have shown that we can vaccinate against the superantigens and prevent serious disease in animals,” Schlievert says.

“The idea is that either therapeutics or vaccination might be a strategy to block the harmful effects of the superantigens, which gives us the chance to do something about the most serious complications of staph infections.”

The UI scientists used a strain of methicillin resistant staph aureus (MRSA), which is a common cause of endocarditis in humans, in the study. They also tested versions of the bacteria that are unable to produce superantigens. By comparing the outcomes in the animal model of infection with these various bacteria, the team proved that the lethal effects of endocarditis and sepsis are caused by the large quantities of the superantigen staphylococcal enterotoxin C (SEC) produced by the staph bacteria.

The study found that SEC contributes to disease both through disruption of the immune system, causing excessive immune response to the infection and low blood pressure, and direct toxicity to the cells lining the heart.

Low blood flow at the infection site appears to be one of the consequences of the superantigen’s action. Increasing blood pressure by replacing fluids reduced the formation of so-called vegetations – plaque-like meshwork made up of cellular factors from the body and bacterial cells — on the heart valves and significantly protected the infected animals from endocarditis. The researchers speculate that increased blood flow may act to wash away the superantigen molecules or to prevent the bacteria from settling and accumulating on the heart valves.

In addition to Schlievert, the research team included Wilmara Salgado-Pabon, PhD, the first author on the study, Laura Breshears, Adam Spaulding, Joseph Merriman, Christopher Stach, Alexander Horswill, and Marnie Peterson.

The research was funded in part by grants from the National Institutes of Health (AI74283, AI57153, AI83211, and AI73366).

http://www.infectioncontroltoday.com/news/2013/08/bacterial-toxins-cause-deadly-heart-disease.aspx

dn23277-1_300

Hollywood director James Cameron found little evidence of life when he descended nearly 11,000 metres to the deepest point in the world’s oceans last year. If only he had taken a microscope and looked just a few centimetres deeper.

Ronnie Glud at the University of Southern Denmark in Odense, and his colleagues, have discovered unusually high levels of microbial activity in the sediments at the site of Cameron’s dive – Challenger Deep at the bottom of the western Pacific’s Mariana Trench.

Glud’s team dispatched autonomous sensors and sample collectors into the trench to measure microbial activity in the top 20 centimetres of sediment on the sea bed. The pressure there is almost 1100 times greater than at the surface. Finding food, however, is an even greater challenge than surviving high pressures for anything calling the trench home.

Any nourishment must come in the form of detritus falling from the surface ocean, most of which is consumed by other organisms on the way down. Only 1 per cent of the organic matter generated at the surface reaches the sea floor’s abyssal plains, 3000 to 6000 metres below sea level. So what are the chances of organic matter making it even deeper, into the trenches that form when one tectonic plate ploughs beneath another?

Surprisingly, the odds seem high. Glud’s team compared sediment samples taken from Challenger Deep and a reference site on the nearby abyssal plain. The bacteria at Challenger Deep were around 10 times as abundant as those on the abyssal plain, with every cubic centimetre of sediment containing 10 million microbes. The deep microbes were also twice as active as their shallower kin.

These figures make sense, says Glud, because ocean trenches are particularly good at capturing sediment. They are broad as well as deep, with a steep slope down to the deepest point, so any sediment falling on their flanks quickly cascades down to the bottom in muddy avalanches. Although the sediment may contain no more than 1 per cent organic matter, so much of it ends up at Challenger Deep that the level of microbial activity shoots up.

“There is much more than meets the eye at the bottom of the sea,” says Hans Røy, at Aarhus University in Denmark. Last year, he studied seafloor sediments below the north Pacific gyre – an area that, unlike Challenger Deep, is almost devoid of nutrients. Remarkably, though, even here Røy found living microbes.

“With the exception of temperatures much above boiling, bacteria seem to cope with everything this planet can throw at them,” he says.

Journal reference: Nature Geoscience, DOI: 10.1038/ngeo1773

http://www.newscientist.com/article/dn23277-deepest-point-in-the-ocean-is-teeming-with-life.html?cmpid=RSS|NSNS|2012-GLOBAL|online-news

68218_Farringon-Charterhouse-Square-archaeology_-March-2013-thumb-600x460-174532

If you find yourself walking in central London, think about this: not far beneath your feet there may well be human remains. On the edge of Charterhouse Square in the district of Farringdon, engineers were digging an access tunnel for the new Crossrail underground railway when they uncovered 12 skeletons.

“We suspected there might be bodies there,” says Crossrail’s chief archaeologist, Jay Carver. “When the excavation machine uncovered the first bones, we went in and excavated by hand.”

Historical documents suggest the then-lord mayor of London ordered an emergency burial ground to be prepared in Farringdon, in response to the Black Death sweeping Europe in the 14th century.

Relatively few people died in the early stages of the plague and so they were buried in an orderly, east-west orientation. In later years there were more dead, and in their graves bodies are essentially heaped on top of one another. The newly discovered Farringdon bodies, just 2.5 metres below the surface, are neatly oriented and were probably wrapped in shrouds and interred: the Crossrail team have found shroud pins but no fabric remains and no sign of coffins. Pottery found at the same depth as the bodies has been dated to before 1350.

The skeletons will now be removed to the Museum of London Archaeology, where radiocarbon dating will determine the approximate age of the bodies. Skeletons discovered in a plague pit in nearby Smithfield yielded DNA markers identifying the plague bacterium Yersinia pestis.

“Our evidence suggests these are burials associated with that period and therefore that these are people buried during the emergency black death period,” says Carver. “If we can find a signature of that bacterium it will provide some interesting new data about this important historical event.”

The Crossrail team have a licence from the Ministry of Justice allowing them to exhume the remains, and at some point the archaeologists will make a decision about curation. Will the skeletons be reburied?

“They may be placed in a charnel store in a crypt, in case future generations want to study them,” says Carver. “It’s an academic and legal decision.”

http://www.newscientist.com/blogs/shortsharpscience/2013/03/crossrail-plague-skeleton.html?cmpid=RSS|NSNS|2012-GLOBAL|online-news

Polonnaruwa%20meteorite

On 29 December 2012, a fireball lit up the early evening skies over the Sri Lankan province of Polonnaruwa. Hot, sparkling fragments of the fireball rained down across the countryside and witnesses reported the strong odour of tar or asphalt.

Over the next few days, the local police gathered numerous examples of these stones and sent them to the Sri Lankan Medical Research Institute of the Ministry of Health in Colombo. After noticing curious features inside these stones, officials forwarded the samples to a team of astrobiologists at Cardiff University in the UK for further analysis.

The results of these tests, which the Cardiff team reveal today, are extraordinary. They say the stones contain fossilised biological structures fused into the rock matrix and that their tests clearly rule out the possibility of terrestrial contamination.

In total, Jamie Wallis at Cardiff University and a few buddies received 628 stone fragments collected from rice fields in the region. However, they were able to clearly identify only three as possible meteorites.

The general properties of these three stones immediately mark them out as unusual. One stone, for example, had a density of less than 1 gram per cubic centimetre, less than all known carbonaceous meteorites. It had a partially fused crust, good evidence of atmospheric heating, a carbon content of up to 4 per cent and contained an abundance of organic compounds with a high molecular weight, which is not unknown in meteorites. On this evidence, Wallis and co think the fireball was probably a small comet.

The most startling claims, however, are based on electron microscope images of structures within the stones (see above). Wallis and co say that one image shows a complex, thick-walled, carbon-rich microfossil about 100 micrometres across that bares similarities with a group of largely extinct marine dinoflagellate algae.

They say another image shows well-preserved flagella that are 2 micrometres in diameter and 100 micrometres long. By terrestrial standards, that’s extremely long and thin, which Wallis and co interpret as evidence of formation in a low-gravity, low-pressure environment.

Wallis and co also measured the abundance of various elements in the samples to determine their origin. They say that low levels of nitrogen in particular rule out the possibility of contamination by modern organisms which would have a much higher nitrogen content. The fact that these samples are also buried within the rock matrix is further evidence, they say.

Wallis and co are convinced that the lines of evidence they have gathered are powerful and persuasive. “This provides clear and convincing evidence that these obviously ancient remains of extinct marine algae found embedded in the Polonnaruwa meteorite are indigenous to the stones and not the result of post-arrival microbial contaminants,” they conclude.

There’s no question that a claim of this kind is likely to generate controversy. Critics have already pointed out that the stones could have been formed by lightning strikes on Earth although Wallis and co counter by saying there was no evidence of lightning at the time of the fireball and that in any case, the stones do not bear the usual characteristics of this kind of strike. What’s more, the temperatures generated by lightning would have destroyed any biological content.

Nevertheless, extraordinary claims require extraordinary evidence and Wallis and co will need to make their samples and evidence available to the scientific community for further study before the claims will be taken seriously.

If the paper is taken at face value, one obvious question that arises is where these samples came from. Wallis and co have their own ideas: “The presence of fossilized biological structures provides compelling evidence in support of the theory of cometary panspermia first proposed over thirty years ago,” they say.

This is an idea put forward by Fred Hoyle and Chandra Wickramasinghe, the latter being a member of the team who has carried out this analysis.

There are other explanations, of course. One is that the fireball was of terrestrial origin, a remnant of one of the many asteroid impacts in Earth’s history that that have ejected billions of tonnes of rock and water into space, presumably with biological material inside. Another is that the structures are not biological and have a different explanation.

Either way, considerably more work will have to be done before the claims from this team can be broadly accepted. Exciting times ahead!

http://www.technologyreview.com/view/512381/astrobiologists-find-ancient-fossils-in-fireball-fragments/

Thanks to Kebmodee for bringing this to the attention of the It’s Interesting community.

sn-atmosphere

Each year, hundreds of millions of metric tons of dust, water, and humanmade pollutants make their way into the atmosphere, often traveling between continents on jet streams. Now a new study confirms that some microbes make the trip with them, seeding the skies with billions of bacteria and other organisms—and potentially affecting the weather. What’s more, some of these high-flying organisms may actually be able to feed while traveling through the clouds, forming an active ecosystem high above the surface of the Earth.

The discovery came about when a team of scientists based at the Georgia Institute of Technology in Atlanta hitched a ride on nine NASA airplane flights aimed at studying hurricanes. Previous studies carried out at the tops of mountains hinted that researchers were likely to find microorganisms at high altitudes, but no one had ever attempted to catalog the microscopic life floating above the oceans—let alone during raging tropical storms. After all, it isn’t easy to take air samples while your plane is flying through a hurricane.

Despite the technical challenges, the researchers managed to collect thousands upon thousands of airborne microorganisms floating in the troposphere about 10 kilometers over the Caribbean, as well as the continental United States and the coast of California. Studying their genes back on Earth, the scientists counted an average of 5100 bacterial cells per cubic meter of air, they report in the Proceedings of the National Academy of Sciences. Although the researchers also captured various types of fungal cells, the bacteria were over two orders of magnitude more abundant in their samples. Well over 60% of all the microbes collected were still alive.

The researchers cataloged a total of 314 different families of bacteria in their samples. Because the type of genetic analysis they used didn’t allow them to identify precise species, it’s not clear if any of the bugs they found are pathogens. Still, the scientists offer the somewhat reassuring news that bacteria associated with human and animal feces only showed up in the air samples taken after Hurricanes Karl and Earl. In fact, these storms seemed to kick up a wide variety of microbes, especially from populated areas, that don’t normally make it to the troposphere.

This uptick in aerial microbial diversity after hurricanes supports the idea that the storms “serve as an atmospheric escalator,” plucking dirt, dust, seawater, and, now, microbes off Earth’s surface and carrying them high into the sky, says Dale Griffin, an environmental and public health microbiologist with the U.S. Geological Survey in St. Petersburg, Florida, who was not involved in the study.

Although many of the organisms borne aloft are likely occasional visitors to the upper troposphere, 17 types of bacteria turned up in every sample. Researchers like environmental microbiologist and co-author Kostas Konstantinidis suspect that these microbes may have evolved to survive for weeks in the sky, perhaps as a way to travel from place to place and spread their genes across the globe. “Not everybody makes it up there,” he says. “It’s only a few that have something unique about their cells” that allows them survive the trip.

The scientists point out that two of the 17 most common families of bacteria in the upper troposphere feed on oxalic acid, one of the most abundant chemical compounds in the sky. This observation raises the question of whether the traveling bacteria might be eating, growing, and perhaps even reproducing 10 kilometers above the surface of Earth. “That’s a big question in the field right now,” Griffin says. “Can you view [the atmosphere] as an ecosystem?”

David Smith, a microbiologist at NASA’s Kennedy Space Center in Florida, warns against jumping to such dramatic conclusions. He also observed a wide variety of microbes in the air above Oregon’s Mount Bachelor in a separate study, but he believes they must hibernate for the duration of their long, cold trips between far-flung terrestrial ecosystems. “While it’s really exciting to think about microorganisms in the atmosphere that are potentially making a living, there’s no evidence of that so far.”

Even if microbes spend their atmospheric travels in dormancy, that doesn’t mean they don’t have a job to do up there. Many microbial cells are the perfect size and texture to cause water vapor to condense or even form ice around them, meaning that they may be able to seed clouds. If these microorganisms are causing clouds to form, they could be having a substantial impact on the weather. By continuing to study the sky’s microbiome, Konstantinidis and his team hope to soon be able to incorporate its effects into atmospheric models.

http://news.sciencemag.org/sciencenow/2013/01/microbes-survive-and-maybe-thriv.html