News & Current Affairs

July 20, 2009

Alarming Africa male gay HIV rate

Alarming Africa male gay HIV rate

HIV

The reports said more education was needed to combat HIV among gay men

HIV rates among gay men in some African countries are 10 times higher than among the general male population, says research in medical journal the Lancet.

The report said prejudice towards gay people was leading to isolation and harassment, which in turn led to risky sexual practices among gay communities.

But the risks are not limited to gay men, as many of the infected also have female sexual partners.

The report called for greater education and resources in the fight against HIV.

The Oxford University researchers found that the prevalence of HIV/Aids among gay men in sub-Saharan African has been “driven by cultural, religious and political unwillingness to accept [gay men] as equal members of society”.

Lead researcher Adrian Smith told the EXPRESS there was “profound stigma and social hostility at every level of society concerning either same-sex behaviours amongst men, or homosexuality”.

“This has the consequence that this group becomes extremely hard to reach,” he said.

Mr Smith said that gay male sex had always been acknowledged as being particularly dangerous in terms of contracting HIV/Aids.

But gay men were also more likely to be involved in other high-risk behaviours, including sex work, having multiple partners and being in contact with intravenous drug use, he said.

Education crucial

George Kanuma, a gay rights activist in Burundi, told the EXPRESS many men “hide their sexual orientation” to get married and have children, but continue to have sex with men.

“Most of them know that you can contract HIV/Aids or any infection when you are making sex with women, but not when you are having sex with another man,” he said.

Mr Smith said there was “a desperate need for delivering a basic package of prevention for HIV”, including ensuring supplies of condoms.

“There is also a need to sensitise, educate and train those involved in HIV, the interface with men who have sex with men, to educate those involved in care and prevention activities,” he said.

The United Nations Aids agency estimates that 33 million people in the world have HIV, of whom two-thirds live in sub-Saharan Africa.

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July 17, 2009

Tiny lizard falls like a feather

Filed under: Latest — Tags: , , , , , , , , , , , , — expressyoureself @ 6:07 pm
Tiny lizard falls like a feather

The lacertid lizard Holaspis guentheri

Not one to free fall

A tiny species of lizard is so light that it falls to the ground like a feather, scientists have discovered.

Outwardly, little of the animal’s body seems adapted to flying, gliding or moving through the air in any way.

But a slow-motion camera has revealed that when the lizard jumps from a height, it can slow the rate of its descent and land gently on the ground.

The lizard’s surprising aerial ability might help explain how some animals became true gliders.

Details of the little lizard’s talents are published in the Journal of Experimental Biology.

Controlled descent

Active flight, powered by the flapping of wings, has evolved in three living lineages of animals: birds, bats and insects.

But at least 30 different types of animal have evolved the ability to control their aerial descent, by parachuting or gliding to ground.

For example, gliding frogs use huge webbed feet, flying squirrels use long flaps of skin between their legs, and flying fish use their fins to glide.

Other animals have less obvious morphological adaptations.

Gliding snakes flatten and undulate their bodies, which helps to slow their fall while some species of ant are so tiny they can jump out of trees and freefall gently to lower on the trunk without hurting themselves.

So Bieke Vanhooydonck of the University of Antwerp became extremely interested when she read some old scientific papers reporting anecdotal evidence that a relatively ordinary species of lizard might also be able to glide from tree to tree.

Holaspis guentheri belongs to a group of lizards known as lacertids, which live in the Old World.

The lacertid lizard Holaspis guentheri

A slender, flat build helps

Though colourful, they do not stand out in terms of their behaviour, morphology or ecology.

“Also, compared to other gliding lizard species, it does not have any conspicuous morphological adaptations to an aerial lifestyle, ie no cutaneous flaps, webbed feet etc,” says Vanhooydonck.

“It made me very curious about whether these animals were really able to ‘glide’ and if so, how they were accomplishing it.”

Leaping platform

So Vanhooydonck and colleagues in Belgium and France filmed individual lizards leaping from a platform two metres above ground.

They compared the performance of H.guentheri with a rock-dwelling lizard (Podarcis muralis) that never takes to the air, and a highly specialised leaping gecko (Ptychozoon kuhli) that has a range of skin flaps that it uses to parachute to the ground.

For each, they examined the duration of each species’ descent, the horizontal distance it covered and at what speed.

Both the rock-dwelling lizard and H.guentheri landed 50 centimetres from the base of the platform, while the gecko landed up to 1m away. But H.guentheri fell for longer, and more slowly than its rock-dwelling competitor.

“Much to our surprise, H. guentheri is able to slow down its descent and has low impact forces upon landing,” says Vanhooydonck.

In fact, the lizard weighs just 1.5g, which is one third of the rock-dwelling lizard’s weight and one-tenth of the gecko’s.

Once weight was factored in, the researchers found that H.guentheri landed 20cm further away that it should have done had it fallen like a stone.

Leaping gecko (Ptychozoon kuhli)

The leaping gecko P. kuhli is a true glider

“Also its wing loading, the ratio of mass to surface area, is extremely low and in the same range as that of the gekko.”

However, the two species achieve this aerial ability in different ways. As a result of its webbed feet and body flaps, the gecko achieves a low wing loading by having a large surface area.

H. guentheri has a low wing loading too, but by being so light.

X-ray scans of the lizard’s body revealed its bones are packed full of air spaces.

Although the lizard’s light weight and ability to fall gently are linked, it is still unclear whether its air-filled bones are an adaptation for parachuting, or whether they evolved for another reason.

It is also unclear whether H.guentheri glides from tree to tree to escape predators or move about more efficiently.

“Because of [the lizards’] secretive lifestyle, it is very hard to observe them in the wild, but it seems plausible they use it as an escape response,” says Vanhooydonck.

And that could be just how other gliding animals took the first evolutionary steps towards an aerial lifestyle, she says.

June 24, 2009

Right ear is ‘better for hearing’

Filed under: Health and Fitness, Latest, Reviews — Tags: , , , , , , , , , — expressyoureself @ 5:50 pm

Right ear is ‘better for hearing’

Ear

The left-side of the brain processes much of what is heard in the right ear

If you want to get someone to do something, ask them in their right ear, say scientists.

Italian researchers found people were better at processing information when requests were made on that side in three separate tests.

They believe this is because the left side of the brain, which is known to be better at processing requests, deals with information from the right ear.

The findings are reported online in the journal Naturwissenschaffen.

We can also see this tendency when people use the phone, most will naturally hold it to their right ear
Professor Sophie Scott, of University College London

In the first study, 286 clubbers were observed while they were talking with loud music in the background.

In total, 72% of interactions occurred on the right side of the listener.

In the second study, researchers approached 160 clubbers and mumbled an inaudible, meaningless utterance and waited for the subjects to turn their head and offer either their left or their right ear.

They then asked them for a cigarette.

Overall, 58% offered their right ear for listening and 42% their left.

In the third study, the researchers intentionally addressed 176 clubbers in either their right or their left ear when asking for a cigarette.

The researchers obtained significantly more cigarettes when they spoke to the clubbers’ right ear compared with their left.

Brain

In conclusion, the researchers said: “Talk into the right ear you send your words into a slightly more amenable part of the brain.

“These results seem to be consistent with the hypothesised specialisation of right and left hemispheres.”

Professor Sophie Scott, of the Institute of Cognitive Neuroscience at University College London, agreed.

“Most people process speech and language on the left-hand side of the brain and while it is not cut-and-dry a lot of what goes in our right ear will be dealt with by the left-side of the brain.

“The other side of the brain is more involved in things such as interpreting emotion and that is why we have these kind of findings.

“We can also see this tendency when people use the phone, most will naturally hold it to their right ear.”

September 24, 2008

Analysing Bin Laden’s jihadi poetry

Analysing Bin Laden’s jihadi poetry

Undated file image of Osama Bin Laden

The tapes show Osama Bin Laden to be ‘an entertainer with an agenda’

To many people Osama Bin Laden is the ultimate barbarian, to others an elusive Muslim warrior. Most know him simply as the world’s most wanted man.

Few would imagine him as a published poet or wedding raconteur.

But now a host of previously unpublished speeches made by the man accused of planning the 9/11 attacks on the US are to be made public.

They include sermons and readings delivered at a wide range of events from weddings to jihadi recruitment sessions.

The material was discovered on a dozen of 1,500 cassettes found in al-Qaeda’s headquarters in Kandahar, Afghanistan, which was evacuated during the US-led invasion in 2001.

Encompassing recordings from the late 1960s until the year 2000, the collection includes hundreds of sermons by Islamic scholars, political speeches by al-Qaeda’s top strategists and even footage of live battles – as well as recordings of the group’s reclusive leader.

According to one US linguistics expert, Flagg Miller, who has spent five years analysing the material, the tapes provide an audio library of Bin Laden’s development as an orator.

The assistant professor of religious studies at the University of California, Davis said the recordings also offer “unprecedented insight” into debates within Bin Laden’s circle in the years leading up to the attacks on the US on 11 September 2001.

Jihad and weddings

Prof Miller’s analysis of the tapes shows Saudi-born Bin Laden to be a skilled poet who weaves mystical references as well as jihadist imagery into his verse, reciting 1,400-year-old poetry alongside more current mujahideen-era work.

“[The readings] were sometimes given to large audiences when he was recruiting for jihad in Afghanistan… and other times they were delivered at weddings, or to smaller audiences, possibly in private homes,” Prof Miller, a linguistic anthropologist specialising in the Middle East, told.

Poetry is important to Bin Laden’s core audiences of radical Islamists and disaffected youth, and his verses have been picked up by his followers around the world and used in their own work, said Prof Miller.

“The violence and barbarism of war can sicken anybody and poetry is a way to frame that violence in higher ethics,” he said.

However, some scholars have objected to the publication of Bin Laden’s poetry, saying the work has only sparked interest because of the notoriety of its author, and that publishing the verse gives a forum to a reviled figure.

In one of his own poems, Bin Laden, whose whereabouts remain unknown, refers to a youth “who plunges into the smoke of war, smiling”.

“He hunches forth, staining the blades of lances red. May God not let my eye stray from the most eminent humans, should they fall,” continues the recital.

The words are believed to have been recorded in the mountainous Afghan cave complex of Tora Bora in 1996, as the al-Qaeda chief made his first declaration of war against the US.

Performer with an agenda

Often identifiable by his distinctive monotone, Bin Laden’s recitals show him to be “the performer, the entertainer with an agenda”, said Prof Miller, who is researching a book analysing the poetry and its role in jihad.

Flagg Miller
Bin Laden uses poetry to tap into the cultural orientation, the history and the ethics of Islam
Prof Flagg Miller
University of California, Davis

“They also show his evolution from a relatively unpolished Muslim reformer, orator and jihad recruiter to his current persona, in which he attempts to position himself as an important intellectual and political voice on international affairs.”

Earlier material is littered with references to tribal poetry, Koranic verses and mystical allusions – mountains, for example, are used as metaphors to help his followers avoid the temptations of the secular world.

In one instance the man accused of orchestrating bombings in East Africa, Indonesia, Morocco, Saudi Arabia and Turkey, as well as the US, describes himself as a “warrior poet”, whose words will lead his followers to an idyllic refuge in the Hindu Kush mountains.

More recent recordings are both more professionally produced and more overtly political – the anti-Western rhetoric with which the world has become familiar since the 9/11 attacks.

Prof Miller said that if alive, Bin Laden would still be writing poetry, which is central to the oral traditions of his tribal culture.

“Poetry is part of the oral tradition in the Arab world, which Bin Laden uses to tap into the cultural orientation, the history and the ethics of Islam,” he said.

The tapes are currently being cleaned and digitised at Yale University in the US and public access is expected to be granted in 2010.

Prof Miller’s findings are published in the October issue of the journal, Language and Communication.

September 17, 2008

Tea ‘healthier’ drink than water

Tea ‘healthier’ drink than water

Image of a mug of tea

The researchers recommend people consume three to four cups a day

Drinking three or more cups of tea a day is as good for you as drinking plenty of water and may even have extra health benefits, say researchers.

The work in the European Journal of Clinical Nutrition dispels the common belief that tea dehydrates.

Tea not only rehydrates as well as water does, but it can also protect against heart disease and some cancers, UK nutritionists found.

Experts believe flavonoids are the key ingredient in tea that promote health.

Healthy cuppa

These polyphenol antioxidants are found in many foods and plants, including tea leaves, and have been shown to help prevent cell damage.

Tea replaces fluids and contains antioxidants so its got two things going for it
Lead author Dr Ruxton

Public health nutritionist Dr Carrie Ruxton, and colleagues at Kings College London, looked at published studies on the health effects of tea consumption.

They found clear evidence that drinking three to four cups of tea a day can cut the chances of having a heart attack.

Some studies suggested tea consumption protected against cancer, although this effect was less clear-cut.

Other health benefits seen included protection against tooth plaque and potentially tooth decay, plus bone strengthening.

Dr Ruxton said: “Drinking tea is actually better for you than drinking water. Water is essentially replacing fluid. Tea replaces fluids and contains antioxidants so it’s got two things going for it.”

Rehydrating

She said it was an urban myth that tea is dehydrating.

“Studies on caffeine have found very high doses dehydrate and everyone assumes that caffeine-containing beverages dehydrate. But even if you had a really, really strong cup of tea or coffee, which is quite hard to make, you would still have a net gain of fluid.

“Also, a cup of tea contains fluoride, which is good for the teeth,” she added.

There was no evidence that tea consumption was harmful to health. However, research suggests that tea can impair the body’s ability to absorb iron from food, meaning people at risk of anaemia should avoid drinking tea around mealtimes.

Tea is not dehydrating. It is a healthy drink
Claire Williamson of the British Nutrition Foundation

Dr Ruxton’s team found average tea consumption was just under three cups per day.

She said the increasing popularity of soft drinks meant many people were not drinking as much tea as before.

“Tea drinking is most common in older people, the 40 plus age range. In older people, tea sometimes made up about 70% of fluid intake so it is a really important contributor,” she said.

Claire Williamson of the British Nutrition Foundation said: “Studies in the laboratory have shown potential health benefits.

“The evidence in humans is not as strong and more studies need to be done. But there are definite potential health benefits from the polyphenols in terms of reducing the risk of diseases such as heart disease and cancers.

“In terms of fluid intake, we recommend 1.5-2 litres per day and that can include tea. Tea is not dehydrating. It is a healthy drink.”

The Tea Council provided funding for the work. Dr Ruxton stressed that the work was independent.

September 9, 2008

Hugging benefits fractious chimps

Hugging benefits fractious chimps

Chimps at Chester Zoo (Orlaith Fraser)

The consoling arm of a good friend

If you have just had a big falling out with a colleague, there is nothing better than the comforting and consoling arm of a good friend.

Chimps, it seems, feel the same way, according to a study at Chester Zoo.

The research is said to provide the first evidence that consolation in primates, such as hugging and stroking, can reduce stress levels after a fight.

The behavior could indicate some level of empathy, Dr Orlaith Fraser told the British Association Science Festival.

“We can’t actually say what’s going on in a chimpanzee’s mind; we can only deduce from their behavior what’s going on,” the Liverpool John Moores University researcher said.

“Because this behavior is actually reducing stress levels and it’s being offered by a valuable partner, it seems likely that this is an expression of empathy.”

A bit of sympathy

Dr Fraser and colleagues spent 18 months observing 22 adult chimps at Chester Zoo.

They watched closely what happened immediately after the animals had a scrap – perhaps a fight over food, a mate or simply where to sit.

In about 50% of cases, the victim in the fight would be consoled by another member of the group. The soothing was always done by a valuable – or best – friend, a chimp with whom the victim would routinely play or share food.

Chimps at Chester Zoo (S.P.Hill)

Feeling better after a kiss

The consolation usually took the form of a kiss or embrace, a grooming session or even play.

The scientists could see that this activity had the effect of reducing stress levels, indicated by the return to the animals’ normal activities of self-scratching and self-grooming.

“Sympathetic concern” has also been observed in gorillas, bonobos, dogs and even rooks – but it is the calming effect that it had on the Chester Zoo chimps which is said to be a new observation.

“If these chimpanzees are actually motivated by empathy to console victims of aggression, they must first of all be able to recognize that the victim is distressed and then they must know what to do in order to act appropriately to respond to this distress,” said Dr Fraser.

“This is something often thought to be a unique trait to humans, so understanding the link between consolation and stress reduction in chimpanzees is an important step towards understanding whether or not chimpanzees are capable of this level of empathy.”

The results of the Chester Zoo study were recently published in the journal Proceedings of the National Academy of Sciences.

September 5, 2008

Down’s signs ‘seen in stem cells’

Down’s signs ‘seen in stem cells’

A baby girl with Down's syndrome

The researchers suggest they may be able to develop treatments for children

Scientists have revealed the earliest developmental changes that lead to Down’s syndrome.

The team from Barts and the Royal London say the changes to embryonic stem cells are caused by the presence of an extra copy of chromosome 21.

The study, in the American Journal of Human Genetics, says the extra chromosome sets off a chain of genetic changes in the developing embryo.

The Down’s Syndrome Association welcomed the “excellent” research.

Down syndrome belongs to a group of conditions called “aneuploidies”, which are defined by an abnormal loss or gain of genetic material, such as fragments of chromosomes or whole chromosomes.

Aneuploidies cause congenital anomalies that are a prime cause of infant death in Europe and the US, and are currently on the increase with advancing maternal age in European countries.

Around one in every 1,000 babies born in the UK will have Down’s syndrome.

There are 60,000 people in the UK with the condition.

Therapeutic potential

The international team of researchers, which also included scientists from the US, Australia, Spain and Switzerland, looked at embryonic stem cells from mice which had been genetically engineered to carry a copy of human chromosome 21.

“It’s not just important for the development of brain cells but for their maintenance throughout life
Professor Dean Nizetic

They discovered that the presence of the extra chromosome 21, known as trisomy 21, disturbs a key regulating gene called REST, which then disturbs the cascade of other genes that control normal development at the embryonic stem cell stage.

The scientists also found that one gene (DYRK1A) which is present on chromosome 21, acts as the trigger for this disturbance.

Dean Nizetic, professor of cellular and molecular biology at Barts and the London, said the work could one day lead to molecule-based therapies which could alleviate the effects of Down’s syndrome.

“We hope that further research might lead to clues for the design of new therapeutic approaches tackling developmental delay, mental retardation, ageing and regeneration of brain cells, and Alzheimer’s disease.

He said he believed the genetic effects continue throughout life.

“I suspect that it’s not just important for the development of brain cells but for their maintenance throughout life; how cells age and how they can cope with stress.

“That’s an area that could be approached with regard to therapies.”

‘Extremely positive’

Professor Nizetic suggested future research should be directed into basic molecular mechanisms that could one day develop into treatments to children with Down’s syndrome in the first few years of life when the brains are “plastic” and rapidly developing.

And he said that the same areas of the human genome have been thought to play a part in Alzheimer’s disease – so research could also lead to treatments for that condition.

Carol Boys, chief executive for the Down’s Syndrome Association said: “Any research that helps us to understand more about some of the complex medical conditions that are commonly associated with Down’s syndrome can only be a positive step forward.

“The development of therapeutic treatments for these sometimes complicated health problems that can be associated with the condition will hopefully lead to an improvement in the overall health of people of with Down’s syndrome.”

She added: “We understand that research is slow, but the initial results look extremely positive and we look forward to the continuation of the excellent work of this dedicated research team with interest.”

August 26, 2008

Mums ‘accept natural birth risks’

Mums ‘accept natural birth risks’

Pregnant woman

About a quarter of UK births are carried out by Caesarean section

First-time mothers-to-be will accept greater risks than clinicians for a natural birth, research suggests.

A Sydney, Australia study also found the women prepared to accept higher pain levels, reports the British Journal of Obstetrics and Gynaecology.

Researchers asked 102 pregnant women and 341 midwives, obstetricians and other doctors what complications would make them choose a Caesarean section.

The journal editor said doctors were “biased”, having seen things go wrong.

This indicates that experiencing labour and attempting a normal birth are two very important priorities in women’s decision-making
Professor Philip Steer
Editor in chief, BJOG

Approximately one in four pregnancies in the UK ends in a Caesarean section, and most are offered in the face of potential complications such as the baby lying in the wrong position for natural birth.

But the Royal Prince Alfred Hospital study suggested that women, given an informed choice, were less likely than the professionals treating them to take a more cautious approach.

A total of 102 women, 84 midwives, 166 obstetricians, 12 urogynaecologists and 79 colorectal surgeons were interviewed to find out whether different complications would prompt them to choose a Caesarean.

Researchers asked them about mild complications such as a prolonged birth and superficial tears to severe problems such as anal and urinary incontinence, vaginal prolapse and severe tearing.

In all categories, the pregnant women were far more likely to be prepared to put up with complications in order to have a natural birth than their midwives or doctors.

Priorities

Study author Catherine Turner said: “Our study found that pregnant women were more likely to aim for a vaginal delivery, and they accept a higher threshold of risks from vaginal delivery when compared with clinicians.”

Professor Philip Steer, the journal’s editor in chief, said: “This indicates that experiencing labor and attempting a normal birth are two very important priorities in women’s decision-making.

“It may also indicate that doctors are biased by their inevitable involvement in complex cases, or labours where things have gone wrong.”

Belinda Phipps, chief executive of the National Childbirth Trust, agreed that health professionals could let their own negative experiences influence the recommendations they gave to women.

“If they’ve seen a traumatic birth, or been involved in a tragedy, there is no debriefing for them.

“It can mean they are more judgemental about the risks involved.”

She added: “I recognise that this is very difficult to avoid, but they need to realise that for most women, this is something that they feel it is important to do for themselves.”

August 23, 2008

Face transplant ‘double success’

Face transplant ‘double success’

The Lancet

This man had been attacked by a bear

Successful results from two more face transplants will speed progress towards similar operations in other countries, say experts.

The Lancet journal reported operations involving a bear attack victim in China, and a French patient with a massive facial tumour had taken place.

The Chinese patient was given not just the lip, nose, skin and muscle from a donor, but even some facial bone.

Specialists in London are working towards the UK’s first transplant.

Frenchwoman Isabel Dinoire became the world’s first face transplant patient in 2005 after being savaged by a pet dog. She described the results of the operation as a “miracle”.

The latest operations were just as complex, but involved different challenges for French and Chinese surgeons.

Face transplantation has moved from ethical debate to surgical reality
French transplantation team

The first operation took place in April 2006. The patient was a farmer from a remote village in Yunnan province in China, who had been attacked by a bear 18 months earlier, leaving a huge section of tissue missing from the right side of his face.

The operation, at Xijing Hospital in Xi’an City, used the face of a 25-year-old man who had died in a traffic accident.

Despite immune-suppressing treatment, the patient had to battle his body’s attempt to reject the new tissue on three occasions.

His doctors said they now believed that face transplantation was a viable long-term option.

The second operation, carried out in Paris in January 2007, involved a 29-year-old man disfigured by a neurofibroma, a massive tumour growing on his facial nerves.

Its removal was timed to coincide with a face transplant, and a year later, doctors again declared the operation a success.

The patient told them that previously he had been considered a “monster”, but now felt like an anonymous person in the crowd.

The procedure, they said, had moved “from ethical debate to surgical reality”.

Moving forward

In the UK, surgeons at the Royal Free Hospital in London are making preparations to carry out the operation if the right combination of patient and donor becomes available.

Professor Iain Hutchison, a consultant oral and maxillofacial surgeon at Barts and the London Hospital, and founder of the “Saving Faces” charity, said that the twin successes would offer more encouragement for surgical teams considering carrying out their own operations.

He said: “This takes a step forward in two ways – firstly the use of bone as well as skin – and next is carrying out this operation on someone with a benign tumour.

“There will always be limitations to this – the main one would be a societal constraint – a lack of suitable donors.

“However, there is certainly demand for this, with the major area being for people with facial burns.”

Roger Green, president of the British Association of Plastic, Reconstructive and Aesthetic Surgeons, said: “This particular surgery is a way of giving back a life to a patient who has been horribly scarred by burns, trauma or a tumour.

“However, we must acknowledge the long-term medical risks, such as transplant rejection and the need for life-long medication, associated with the procedure. There is also the potential of psychological impact following such a transplant.”

August 14, 2008

Arsenic-munching bacteria found

Arsenic-munching bacteria found

Bacteria(USGS)

Microbial biofilms form in rocky pools, fed by hot springs containing arsenic

In the warm, bubbling pools of Mono Lake in California, scientists have isolated a bacterium that fuels itself on arsenic.

Combining light and arsenic, these bacteria make their food and multiply using a chemical that is toxic to most other life forms.

The researchers think using arsenic as an energy source was a process used by ancient bacteria.

Their findings are reported in the journal Science.

Ronald Oremland of the US Geological Survey explained that these bacteria are photosynthetic, using sunlight – like plants – to turn carbon dioxide into food.

What is different about them is that instead of using water in this process, they use arsenic.

The US-based researchers isolated the bacterium from the lake, which lies at the foot of the Sierra Nevada.

Colour film

“These lakes are fed by hydrothermal waters that leach out arsenic-containing minerals from the surrounding rocks,” Dr Oremland told.

The researchers noticed that the bacteria had colonised small, hot pools, forming colorful “biofilms”.

MonoLake(USGS)

Bacteria living in Mono Lake, California can survive the high levels of arsenic

“We suspected that these bacteria were using arsenic to make a living, so we scraped the biofilms off the rock and studied them under laboratory conditions.”

By first withholding light, then arsenic, the team showed that the bacteria required both to grow.

This the first time an organism has been found that can use arsenic to photosynthesise under anaerobic conditions, Dr Oremland believes.

He suspects that this is an ancient ability in bacteria.

“We think that bacteria were photosynthesising before oxygen was present in the atmosphere,” he said.

Primordial niche

Understanding how arsenic is metabolized by bacteria could help scientists comprehend its damaging affects inside human cells.

Worldwide, 144 million people are exposed to toxic levels of arsenic in their drinking water.

It enters the body’s cells by diffusion; and once inside, it disrupts how they function by binding to their machinery, inactivating it, and disrupting the way energy is transported.

Long-term exposure can lead to skin disease and kidney and bladder cancer, and it is thought to stunt the intellectual development of children.

The most arsenic-contaminated regions are in India, Pakistan, and China, where soluble arsenic in ground waters is above the World Health Organization’s (WHO) suggested maximum safe level of 10 parts per billion.

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