Bats adjust squeaks to focus sonar

Human eyes, set as they are in front-facing sockets, give us a limited angle of view: we see what is directly in front of us, with only a few degrees of peripheral vision. But bats can broaden and narrow their 'visual field' by modulating the frequency of the squeaks they use to navigate and find prey, researchers in Denmark suggest today in Nature¹.

Bats find their way through the night by emitting sonar signals and using the echoes that return to them to create a map of their surroundings — a process called echolocation. Researchers have long known that small bats emit higher-frequency squeaks than larger bats, and most assumed that the difference arises because the smaller animals must catch smaller insects, from which low-frequency sound waves with long wavelengths do not reflect well.

That didn't sound right to Annemarie Surlykke, a neurobiologist who studies bat echolocation at the University of Southern Denmark in Odense. “When you look at the actual frequencies, small bats would be able to detect even the smallest prey they take with a much lower frequency,” she says. “So there must be another reason.”

Surlykke and her colleagues decided to test the hypothesis by studying six related species of bat that varied in size. They captured the animals in the wild and set them loose in a flight room — a pitch-dark netted corridor 2.5 metres high, 4.8 metres wide and 7 metres long, rigged on all sides with microphones and infrared cameras. “It’s a pretty confined space, so this corresponds to flying close to vegetation,” says Surlykke.

Direct call

By measuring the time it took for a bat’s echolocation signals to hit different microphones, Surlykke’s team could pinpoint the exact location of the animals in flight. They could then analyse the intensity of each signal, as well as the size of each animal’s mouth, to reconstruct the width of the sound beam.

Under the specific conditions of the flight room, the researchers found, the animals adjusted the frequency of their signals and the openings of their mouths to come up with the same beam width for their echolocation calls — around 37°, no matter the animal's size. In past studies, two species tested in the field used different beam widths depending on whether they were scanning for prey from on high or about to dive in for the capture.

“That means that the small bats, we think now, are not forced to use the high frequency to detect their prey, but to keep the beam narrow,” says Surlykke. A lower-frequency vocalization would broaden the beam, making it hit more objects and increase the noise in the signal, which would make echolocation more difficult. So small species need to use high frequencies simply because their mouths are petite.

Out and about

Hans-Ulrich Schnitzler, who studies echolocation at the University of Tübingen in Germany, lauds the finding for bringing a previously unconsidered parameter to the discipline. “I really think it opens up a new field,” he says.

However, he thinks that the group’s conclusion is not yet definitive. “It now has to be documented for other species and for flying out in nature — in the open, in the forest, in different habitats,” says Schnitzler.

Surlykke notes that her group examined only bats that echolocate using their mouths. “One of the intriguing questions is how this works in nose-emitting bats,” she says.

The study raises the question of how bats perceive their environment, says Surlykke, and her group plans to look at this too.

“The fact that the beam is constant means the important thing is in the bat’s head — and not in the environment,” says James Simmons, a neurobiologist at Brown University in Providence, Rhode Island. “Ultimately,” he says, “it’s a psychological problem.”

Source:Nature

MicroRNAs 103 and 107 regulate insulin sensitivity

Defects in insulin signalling are among the most common and earliest defects that predispose an individual to the development of type 2 diabetes^1, 2, 3. MicroRNAs have been identified as a new class of regulatory molecules that influence many biological functions, including metabolism^4, 5. However, the direct regulation of insulin sensitivity by microRNAs in vivo has not been demonstrated. Here we show that the expression of microRNAs 103 and 107 (miR-103/107) is upregulated in obese mice. Silencing of miR-103/107 leads to improved glucose homeostasis and insulin sensitivity. In contrast, gain of miR-103/107 function in either liver or fat is sufficient to induce impaired glucose homeostasis. We identify caveolin-1, a critical regulator of the insulin receptor, as a direct target gene of miR-103/107. We demonstrate that caveolin-1 is upregulated upon miR-103/107 inactivation in adipocytes and that this is concomitant with stabilization of the insulin receptor, enhanced insulin signalling, decreased adipocyte size and enhanced insulin-stimulated glucose uptake. These findings demonstrate the central importance of miR-103/107 to insulin sensitivity and identify a new target for the treatment of type 2 diabetes and obesity.

Source:Nature

Hubble Eyes a Loose Spiral Galaxy

The galaxy is viewed from an angle, allowing Hubble to reveal its spiral nature clearly. The faint, loose spiral arms can be distinguished as bluish features swirling around the galaxy's nucleus. This blue tinge emanates from the hot, young stars located in the spiral arms. The arms of a spiral galaxy have large amounts of gas and dust, and are often areas where new stars are constantly forming.

The galaxy's most characteristic feature is a bright elongated nucleus. The bulging central core usually contains the highest density of stars in the galaxy, where typically a large group of comparatively cool old stars are packed in this compact, spheroidal region.

One feature common to many spiral galaxies is the presence of a bar running across the center of the galaxy. These bars are thought to act as a mechanism that channels gas from the spiral arms to the center, enhancing the star formation.

Recent studies suggest that ESO 499-G37's nucleus sits within a small bar up to a few hundreds of light-years along, about a tenth the size of a typical galactic bar. Astronomers think that such small bars could be important in the formation of galactic bulges since they might provide a mechanism for bringing material from the outer regions down to the inner ones. However, the connection between bars and bulge formation is still not clear since bars are not a universal feature in spiral galaxies.

The galaxy ESO 499-G37 lies in the southern border of the constellation of Hydra, which is shared with Antlia.

ESO 499-G37 was first observed in the late seventies within the ESO/Uppsala Survey of the ESO (B) atlas. This was a joint project undertaken by the European Southern Observatory (ESO) and the Uppsala Observatory, which used the ESO 1-metre Schmidt telescope at La Silla Observatory, Chile, to map a large portion of the southern sky looking for stars, galaxies, clusters, and planetary nebulae.

This picture was created from visible and infrared exposures taken with the Wide Field Channel of the Advanced Camera for Surveys. The field of view is approximately 3.4 arcminutes wide.

Source:sciencedaily

Single photon could detect quantum-scale black holes

Space is not smooth: physicists think that on the quantum scale, it is composed of indivisible subunits, like the dots that make up a pointillist painting. This pixellated landscape is thought to seethe with black holes smaller than one trillionth of one trillionth of the diameter of a hydrogen atom, continuously popping in and out of existence.

That tumultuous vista was proposed decades ago by theorists struggling to marry quantum theory with Einstein’s theory of gravity — the only one of nature’s four fundamental forces not to have been incorporated into the standard model of particle physics. If it is true, the idea could provide a deeper understanding of space-time and the birth of the Universe.

Scientists have attempted to use the Large Hadron Collider, gravitational wave detectors and observations of distant cosmic explosions to determine whether space is truly grainy, but results have so far been inconclusive. Now, Jacob Bekenstein, a theoretical physicist at the Hebrew University of Jerusalem, has proposed a simple tabletop experiment to find out, using readily available equipment¹.

As in previous experiments, Bekenstein’s set-up is designed to examine the problem on the scale of 1.6 × 10⁻³⁵ metres. This 'Planck length' is thought to mark the scale at which the macroscopic concept of distance ceases to have meaning and quantum fluctuations begin to cause space-time to resemble a foamy sea.

No instrument can directly measure a displacement as small as 10⁻³⁵ metres. Instead, Bekenstein proposes firing a single particle of light, or photon, through a transparent block, and indirectly measuring the minuscule distance that the block moves as a result of the photon’s momentum.

Light and mass

The wavelength of the photon and the mass and size of the block are carefully chosen so that the momentum is just large enough to move the block’s centre of mass by one Planck length. If space-time is not grainy on this scale, then each photon will pass through the block and be recorded by a detector on the other side. However, if space-time is grainy, the photon is significantly less likely to make it all the way through the block. “I argue that the consequence of that crossing — the translation of the block by a Planck length or so — is something nature would not like,” says Bekenstein.

If quantum fluctuations in length are important on the Planck scale, a sea of black holes, each with a Planck-scale radius, will readily form. Anything that falls into one of those black holes will be unable to escape until the hole disappears. So if the centre of mass of the moving block falls into one of the holes, the block's movement will be impeded (the photons are much larger than the Plank length, and so are not bothered by the miniature black holes).

Conservation of momentum in the experimental set-up requires that the photon cannot make it through the block if the block fails to move by a Planck length. So if fewer photons than expected are seen by the detector, it would indicate that the block's movement has been impeded by black holes, and that space-time exhibits quantum features at the Planck scale.

Bekenstein’s design is simple, so the experiment could easily be put into practice using established methods of generating and detecting single photons, says Igor Pikovski, a quantum physicist at the Vienna Center for Quantum Science and Technology. Nevertheless, he adds, “distinguishing possible quantum gravitational effects from other effects will be very challenging”.

Earlier this year, Pikovski and his colleagues published² another scheme for probing the graininess of space-time in the laboratory, using optical pulses and and the principles of quantum theory to drive a system from an initial configuration to the desired final state. “The truth is that we do not know at what exact scale quantum gravity will play a significant role,” says Pikovski. “There is plenty of room for granularity at much larger lengths [than the Planck length] and we do not have a full theory that could tell us the answer.” Experiments such as Bekenstein’s or his own may provide some of the first evidence for an answer, he adds.

Source: http://www.nature.com/news/single-photon-could-detect-quantum-scale-black-holes-1.11871

How Earth's wandering poles return home

A number of times over the past one billion years, the Earth's surface has "wandered" relative to its rotational axis – before returning to its original position. Now, a team of geophysicists from the US and Canada says it has developed a theory that explains this curious phenomenon of "oscillatory true polar wander". Understanding the mechanics behind polar wander is crucial, as a shift could tip the Earth over by as far as 50° over a period of 10–100 million years and this would cause profound global environmental and geological changes.

Wandering Earth?

True polar wander (TPW) can be defined as the relative movement between the mantle (and so the surface of the Earth) and the Earth's spin axis or its rotational axis. Incredibly, researchers believe that over the past one billion years, the Earth's surface has "tipped over" and then returned to its original location six times along the same axis – this is the process of "oscillatory true polar wander". Scientists have worked this out by studying magnetism in rocks – a discipline known as "paleomagnetism". If a rock cools in a magnetic field, it records the magnetic properties of the field and these can be decoded in the lab millions of years later. So, by measuring changes in the orientation of the Earth's magnetic field that are stored in ancient rocks, scientists can "see" the effects of the oscillatory TPW.

Extreme shifts

"Someone sitting on the Earth would have seen the pole shift up to 50° and then turn around and return close to its original location, all in tens of millions of years," explained geophysicist Jerry Mitrovica of the Earth and Planetary Science Department at Harvard University. "But an observer floating in space would actually see the rotational axis stay relatively vertical and the Earth's surface tip over and then back." Unsurprisingly, these rather extreme and dramatic shifts can be linked to global changes in all large-scale Earth systems such as the carbon cycle, climate and even evolution. "After all, if it happened today, a shift of 50° one way might put Boston [Massachusetts] near the north pole, while a shift in the opposite direction would bring Boston near the equator," said Mitrovica.

But this in itself is not news – earth scientists have known for a while that TPW does occur and they even know why. They believe that the initial shift of the pole – or the Earth tipping over – is caused by large-scale flows in the Earth's interior known as "mantle convection", involving thermal convection currents that carry heat from the Earth's core to the surface. This is the same process that drives continental drift and plate tectonics. So, mantle convection disturbs the rotational equilibrium of the Earth and the result is a shift in the relative orientation of the Earth's solid surface and its rotational axis.

There and back again

What has eluded researchers is a theory that clearly explains how and why the pole returns to its original location, or the "oscillatory true polar wander". In the new work, graduate student Jessica Creveling, also of the Earth and Planetary Science Department at Harvard, along with Mitrovica and colleagues, provides an explanation. The researchers, using computer simulations and modelling, said that a combination of two mechanisms brings the "wandering" pole back to its original location.

The first mechanism relates to the Earth's equatorial bulge. The Earth is not a perfect sphere – rather it is an oblate spheroid, as it is flattened at the poles and bulges at the equator. So there is a difference in the radius of the Earth as measured from the centre to the equator compared with the poles – it is approximately 20 km greater at the equator. This band of excess mass forms because the Earth is rotating, which causes the equator to bulge outwards. "But the Earth's bulge is generally a bit larger than it should be...which is true even today. And this extra bulge, or fatness, acts to stabilize the Earth's rotation," explained Mitrovica. He likened this to the heavy weight that is placed at the bottom of a plastic punching-bag toy, which acts to bring the bag back to being vertical if it is punched sideways. In a similar manner, if the Earth, with its bulging equator, tips over, it prefers to right itself again. "So, this girdle of excess mass actually has a very stabilizing effect, acting as a self-righting mechanism for the Earth's rotation," he said.

The second mechanism relates to the strength of the tectonic plates. If the Earth's surface tips over relative to the rotational axis, the 12 larger tectonic plates all get deformed to a small extent, like elastic bands. In a similar way to a stretched elastic band, the plates want to go back to their original size, and these stabilizing elastic stresses also play a role in the oscillatory return of the pole. A clue that this might be the case is the fact that past polar-oscillation events seem to have happened when the Earth's continents were gathered together into one "supercontinent", a process that has repeated a number of times in Earth's history. The last supercontinent, known as Pangea, was formed 200 million years ago.

Efficiency of combined effects

Mitrovica pointed out that while Creveling was running her simulation, neither single mechanism could cause the pole to return – it was only a combination of both effects that did it. "What also really surprised me was the efficiency of the effects to pull and push the poles during a period of about 10 million years," said Mitrovica. "This paper made a believer out of me and I was a sceptic." He explains that other researchers might remain sceptical about the theory and that only more evidence gathered based on paleomagnetic field studies will provide the necessary evidence. The team also hopes to better determine how common or rare these events are. "Every rock cooling at the time of a tilt will show the evidence of it and we need to find that," said Mitrovica.

The team is also keen to determine just how drastic the effects of a shift are. It is believed that a shift would cause a significant change in the climate of every place on Earth, as well as changes in the sea level and the carbon cycle. Mitrovica believes that the consequences of these large-scale events would have left their own mark on the Earth's systems and they too should be studied in the future.

The research was published in Nature.

Need a Lot of Sleep? An Antidote for Hypersomnia

The results are scheduled for publication online November 21 by the journal Science Translational Medicine.

Some members of this patient population appear to have a distinct, disabling sleep disorder called "primary hypersomnia," which is separate from better-known conditions such as sleep apnea or narcolepsy. They regularly sleep more than 70 hours per week and have difficulties awakening. When awake, they still have reaction times comparable to someone who has been awake all night. Their sleepiness often interferes with work or school attendance, and conventional treatments such as stimulants bring little relief.

"These individuals report feeling as if they're walking around in a fog -- physically, but not mentally awake," says lead author David Rye, MD, PhD, professor of neurology at Emory University School of Medicine and director of research for Emory Healthcare's Program in Sleep. "When encountering excessive sleepiness in a patient, we typically think it's caused by an impairment in the brain's wake systems and treat it with stimulant medications. However, in these patients, the situation is more akin to attempting to drive a car with the parking brake engaged. Our thinking needs to shift from pushing the accelerator harder, to releasing the brake."

In a clinical study with seven patients who remained sleepy despite above-ordinary sleep amounts and treatment with stimulants, Emory researchers showed that treatment with the drug flumazenil can restore alertness, although flumazenil's effectiveness was not uniform for all seven. Alertness was gauged through the psychomotor vigilance test, a measurement of reaction time.

Flumazenil is usually used in cases of overdose of benzodiazepines, a widely used class of anesthetics and sedatives such as diazepam (Valium) and zolpidem (Ambien). Evidence in the paper suggests that the sleep-inducing substance in patients' cerebrospinal fluid is not a benzodiazepine drug, even though flumazenil counteracts it. Identifying the mysterious "somnogen," which appears to be produced by the body, could give scientists greater insight into how our brains regulate states of consciousness such as alertness and sleep.

"Primary hypersomnias are disabling and poorly understood. This study represents a breakthrough in determining a cause for these disorders and devising a rational approach to therapy," says Merrill Mitler, PhD, a program director at the National Institute of Neurological Disorders and Stroke, part of the National Institutes of Health." Further research is required to determine whether or not the results apply to the majority of patients."

The team of researchers involved in this effort includes Rye; Andrew Jenkins, PhD, Emory assistant professor of anesthesiology; and Kathy Parker, PhD, RN, FAAN, previously at Emory and now at University of Rochester Medical Center.

The paper describes how samples of patients' cerebrospinal fluid (CSF) contain a substance that enhances the effects of the brain chemical GABA (gamma-amino butyric acid). GABA is one of the main inhibitory chemicals of the nervous system -- alcohol, barbituates and benzodiazepines all enhance the effects of GABA. In the laboratory, the size of the effect on GABA receptor function is more than twice as large in the hyper-sleepy patients, on average, than in control samples.

"In some of the more severely affected patients, we estimated the magnitude of the GABA-enhancing effect as nearly equivalent to that expected for someone receiving sedation for outpatient colonoscopy," Rye says. "This is a level of impaired consciousness that many subjects had to combat on almost a daily basis in order to live their usual lives."

The ICSD-2 (International Classification of Sleep Disorders) terms this disorder "primary hypersomnia" and the proposed DSM-V describes it as "major hypersomnolence disorder." Its prevalence is unclear. The Emory team's findings could potentially provide a biological definition and a treatment for an under-recognized sleep disorder.

The patients in the group examined in the paper have received a variety of diagnoses, including idiopathic hypersomnia and narcolepsy without cataplexy. Cataplexy is a sudden loss of muscle tone, sometimes triggered by surprise or strong emotion, characteristic to narcolepsy. Other members of the group are simply considered "long sleepers" (more than 10 hours per day).

In addition, the identity of the GABA-enhancing substance is not yet known, although Rye and Jenkins are devising strategies to pin it down. Based on its size and sensitivity to certain enzymes, it could be a peptide, similar to but not the same as the hormones oxytocin or hypocretin. Jenkins and his colleagues have shown that the sleep-inducing substance can act on GABA receptors that are not sensitive to benzodiazepines.

"Previous studies with flumazenil indicate that it does not have a wake-promoting effect on most people, so its ability to normalize vigilance in this subpopulation of extremely sleepy patients appears genuinely novel," Rye says.

Source:ScienceDaily

Sleep Problems Cost Billions

If you can't sleep at night, you're not alone. Around ten per cent of the population suffer from insomnia, where you have trouble falling asleep, wake up frequently at night, and still feel tired when the morning comes.

"When you feel tired and indisposed, your performance at work suffers," says Børge Sivertsen, professor at UiB's Department of Clinical Psychology and senior researcher at the Norwegian Institute of Public Health.

Sleep apnea is a more severe problem, affecting four to five per cent of the population. Sufferers can stop breathing for up to 40 seconds several times during the night, putting a huge strain on the heart. As a result, they have many micro-awakenings that stop them from reaching deep sleep.

Bad night, bad day

According to the sleep scientist, a recently-published study from the United States puts the annual losses from insomnia alone at 63.2 billion US dollars annually. Only a third of this was due to actual absence from work; two thirds was due to a loss in productivity while at work.

"An Australian study found that about two per cent of Australia's GDP is lost due to sick leave caused by insomnia and sleep apnea disorder. This shows how common these diseases are and how much they affect work," Sivertsen says.

Danger on the roads

In their own ways, each sleep disorder also has a strong impact on accident statistics. For example, lorry drivers have sedentary jobs, and this increases the risk of developing obesity and sleep apnea.

"The disease is a major cause of the many traffic accidents on American roads," Sivertsen says.

As for insomnia, drug use can cause problems. Sivertsen's studies show that sedatives can cause users to feel less rested during the daytime.

"Sleep medication may work in the short term, but after six weeks of use we noticed a decrease in deep sleep. Sleep may be uninterrupted, but you may not necessarily get quality sleep," he says.

Testing every treatment there is

Sleep disorder sufferers are often major health care users, which leads to an increase in social costs.

"When you feel bad, you will try every treatment there is. There is an overconsumption of alternative methods amongst insomnia sufferers. They often consume too much alcohol and visit their GPs, psychologists, physiotherapists, and chiropractors more often."

Sivertsen wants insomnia treatment to become more accessible, and to include cognitive behavioural therapy.

"Several recent studies show that the Internet can be used to offer good and cost-effective methods of treatment. This is particularly true in areas where sleep centres are few and far between," he suggests.

Source:

Star Trek Classroom: Next Generation of School Desks

New results from a 3-year project working with over 400 pupils, mostly 8-10 year olds, show that collaborative learning increases both fluency and flexibility in maths. It also shows that using an interactive 'smart' desk can have benefits over doing mathematics on paper.

Using multi-touch desks in the new classroom, the children were able to work together in new ways to solve and answer questions and problems using inventive solutions. Seeing what your friends are doing, and being able to fully participate in group activities, offers new ways of working in class, the researchers say.

The 'Star Trek classroom' could also help learning and teaching in other subjects.

The findings published in the journalLearning and Instruction, show that children who use a collaborative maths activity in the SynergyNet classroom improve in both mathematical flexibility and fluency, while children working on traditional paper-based activities only improve in flexibility.

During the project, the team found that 45% of students who used NumberNet increased in the number of unique mathematical expressions they created after using NumberNet, compared to 16% of students in the traditional paper-based activity.

Lead researcher, Professor Liz Burd, School of Education, said: "Our aim was to encourage far higher levels of active student engagement, where knowledge is obtained by sharing, problem-solving and creating, rather than by passive listening. This classroom enables both active engagement and equal access.

"We found our tables encouraged students to collaborate more effectively. We were delighted to observe groups of students enhancing others' understanding of mathematical concepts. Such collaboration just did not happen when students used paper-based approaches."

The Durham University team designed software and desks that recognize multiple touches on the desktop using vision systems that see infrared light. The project called SynergyNet set out to integrate a fully collaborative system of desks, building it into the fabric and furniture of the classroom. The new desks with a 'multi-touch' surface are the central component, and these are networked and linked to a main smartboard.

In terms of current teaching, the new system means that the 'move-to-use' whiteboard is by-passed and the new desks can be both screen and keyboard. The desks act like multi-touch whiteboards and several students can use any one desk at once.

The technology allows all students to take part as opposed to one individual dominating.

Researcher, Emma Mercier, School of Education, said: "Cooperative learning works very well in the new classroom because the pupils interact and learn in a different way. The children really enjoy doing maths in this way and are always disappointed when you turn the desks off!

"We can achieve fluency in maths through practice, however, boosting a pupil's ability to find a range of solutions to arithmetic questions is harder to teach. This classroom can help teachers to use collaborative learning to improve their pupils' flexibility in maths."

The teacher plays a key role in the classroom and can send tasks to different tables to individuals and groups. The teacher can also send one group's answers on to the next group to work on and add to, or to the board for a class discussion.

A live feed of the desks goes directly to the teacher who can intervene quickly to help an individual while allowing the group work to continue.

Professor Steve Higgins said: "Technology like this has enormous potential for teaching as it can help the teacher to manage and to orchestrate the learning of individuals and groups of learners to ensure they are both challenged and supported so that they can learn effectively."

Such a classroom may be some way off being a regular feature of schools across the world due to the costs in setting it up, and the level of support needed to make it work, however, in just 3 years the project team have noted major improvements in the technology, and a reduction in costs.

The researchers also recognise that task management in the class environment is an issue requiring thought and planning, but the overall potential of the new classroom for improved numeracy, learning, and on-going assessment is very good.

The project has worked with 12 different schools in the North East.

SynergyNet is one of eight technology enhanced learning research projects funded by the Economic and Social Research Council and the Engineering and Physical Sciences Research Council as part of the £12M Teaching and Learning Research Programme into Technology Enhanced Learning.

The project is an inter-disciplinary collaboration at Durham University between the School of Education, the Department of Psychology and the Department of Computer Science.

Source: Sciencedaily

Algae can draw energy from other plants

Astonishing research finding by biologists at Bielefeld University published in the online journal Nature Communications. Flowers need water and light to grow. Even children learn that plants use sunlight to gather energy from earth and water. Members of Professor Dr. Olaf Kruse's biological research team at Bielefeld University have made a groundbreaking discovery that one plant has another way of doing this. They have confirmed for the first time that a plant, the green alga Chlamydomonas reinhardtii, not only engages in photosynthesis, but also has an alternative source of energy: it can draw it from other plants. This finding could also have a major impact on the future of bioenergy. The research findings have been released on Tuesday 20 November in the online journal Nature Communications published by the renowned journal Nature. Until now, it was believed that only worms, bacteria, and fungi could digest vegetable cellulose and use it as a source of carbon for their growth and survival. Plants, in contrast, engage in the photosynthesis of carbon dioxide, water, and light. In a series of experiments, Professor Dr. Olaf Kruse and his team cultivated the microscopically small green alga species Chlamydomonas reinhardtii in a low carbon dioxide environment and observed that when faced with such a shortage, these single-cell plants can draw energy from neighbouring vegetable cellulose instead. The alga secretes enzymes (so-called cellulose enzymes) that 'digest' the cellulose, breaking it down into smaller sugar components. These are then transported into the cells and transformed into a source of energy: the alga can continue to grow. 'This is the first time that such a behaviour has been confirmed in a vegetable organism', says Professor Kruse. 'That algae can digest cellulose contradicts every previous textbook. To a certain extent, what we are seeing is plants eating plants'. Currently, the scientists are studying whether this mechanism can also be found in other types of alga. Preliminary findings indicate that this is the case. In the future, this 'new' property of algae could also be of interest for bioenergy production. Breaking down vegetable cellulose biologically is one of the most important tasks in this field. Although vast quantities of waste containing cellulose are available from, for example, field crops, it cannot be transformed into biofuels in this form. Cellulose enzymes first have to break down the material and process it. At present, the necessary cellulose enzymes are extracted from fungi that, in turn, require organic material in order to grow. If, in future, cellulose enzymes can be obtained from algae, there would be no more need for the organic material to feed the fungi. Then even when it is confirmed that algae can use alternative nutrients, water and light suffice for them to grow in normal conditions.

 Source: http://www.uni-bielefeld.de/%28en%29/index.html