Category Archives: Biology

Bee Social Activity Tied To Gene

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A gene involved in egg production also helps honeybees exhibit some crucial social behaviors that distinguish them from solitary insects, researchers report in PLoS Biology this week.

The gene vitellogenin, which is involved in egg production in all egg laying animals, coordinates three core aspects of bees’ social life: “It paces the onset of foraging behavior, it primes bees for specialized foraging tasks, and it influences longevity, three very important life-history characteristics for honeybees,” senior author Gro Amdam of Arizona State University told The Scientist.

The results confirm predictions drawn from the sequence of the honey bee genome, which was published last October. The sequence suggested that new, distinguishing social behaviors likely developed from old genes and mechanisms.

“This is a very exciting paper,” Thomas Flatt of Brown University, who did not participate in the study, told The Scientist. “It’s the first mechanistic study to look at the genetic and hormonal regulation of complex social behaviors by a single gene using honeybees as a model organism.”

The Scientist

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Chinese Scientists Fly Pigeons by Remote Control

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Chinese scientists have succeeded in implanting electrodes in the brain of a pigeon to remotely control the bird’s flight, state media said.

Xinhua News Agency said the scientists at the Robot Engineering Technology Research Center at Shandong University of Science and Technology in eastern China used the micro electrodes to command the bird to fly right or left, and up or down.

The implants stimulated different areas of the pigeon’s brain according to electronic signals sent by the scientists via computer, mirroring natural signals generated by the brain, Xinhua quoted chief scientist Su Xuecheng as saying.

It was the first such successful experiment on a pigeon in the world, said Su, who conducted a similar successful experiment on mice in 2005.

msn

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Evolving Robots and a Comparison of Individual vs Group Selection… Awesome

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Living things communicate all the time. They bark, they glow, they make a stink, they thwack the ground. How their communication evolved is the sort of big question that keeps lots of biologists busy for entire careers. One of the reasons it’s so big is that there are many different things that organisms communicate. A frog may sing to attract mates. A plant may give off a chemical to attract parasitoid wasps to attack the bugs chewing its leaves. An ant may lay down pheromone trails to guide other ants to food. Bacteria emit chemical signals to each other so that they can build biofilms that line our lungs and guts.

Communication may work all very well in these cases, but scientists also want to know how they evolved in the first place. Roughly speaking, their question goes something like this. Say you’re an organism living a solitary life. Sending a signal to another member of your species may cost you more than it might bring back in benefits. If you come across some food and suddenly declare, “My, but those are some tasty grubs,” you may find yourself besieged by other members of your species all coming to have some for themselves. You might even attract the attention of a predator and become a meal yourself. So why not just shut up?

There are many ways to attack this question. You can go out and listen to birds. You can genetically engineer bacteria to tinker with their communication system and see what happens. Or you can build an army of robots.

Laurent Keller, an expert on social evolution at the University of Lausanne in Switzerland, chose the latter. Working with robotics experts at Lausanne, he constructed simple robots like the ones shown above. Each robot had a pair of wheeled tracks, a 360-degree light-sensing camera, and an infrared sensor underneath. The robots were controlled by a program with a neural network architecture. In neural networks, inputs come in through various channels and get combined in various combinations, and the combinations then produce outgoing signals. In the case of the Swiss robots, the inputs were the signals from the camera and the infrared sensor, and the output was the control of the tracks.

The scientists then put the robots in a little arena with two glowing red disks. One disk they called the food source. The other was the poison source. The only difference between them was that food source sat on top of a gray piece of paper, and the poison source sat on top of black paper. A robot could tell the difference between the two only once it was close enough to a source to use its infrared sensor to see the paper color.

Then the scientists allowed the robots to evolve. The robots—a thousand of them in each trial of the experiment—started out with neural networks that were wired at random. They were placed in groups of ten in arenas with poison and food, and they all wandered in a haze. If a robot happened to reach the food and detected the gray paper, the scientists awarded it a point. If it ended up by the poison source, it lost a point. The scientists observed each robot over the course of ten minutes and added up all their points during that time. (This part of the experiment was run on a computer simulation to save time and to be able to evolve lots of robots at once.)

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Storing Digital Data In DNA

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For people who want to ensure their words last for their progeny, Japanese scientists have found a way to literally put a message into genes.

A research team said this week it had developed a technology for storing digital data in the DNA of bacteria, which unlike most living organisms can survive for millennia in the right conditions.

Each hay bacillus bacterium can store two megabits—the equivalent of 1.6 million Roman letters. The scientists can take out the microscopic implants in a laboratory and read them so they appear as ordinary text.

The team at Keio University’s Institute for Advanced Biosciences said the technology needs to be perfected but that it was optimistic about its future uses.

“If I wanted to store my personal diary in these live bacteria and take it with me to my grave, then my story can live for thousands and thousands of years,” head researcher Yoshiaki Ohashi said with a laugh.

yahoo

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Chimpanzees ‘Hunt Using Spears’

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Chimpanzees in Senegal have been observed making and using wooden spears to hunt other primates, according to a study in the journal Current Biology.

Researchers documented 22 cases of chimps fashioning tools to jab at smaller primates sheltering in cavities of hollow branches or tree trunks.

The report’s authors, Jill Pruetz and Paco Bertolani, said the finding could have implications for human evolution.

Chimps had not been previously observed hunting other animals with tools.

Pruetz and Bertolani made the discovery at their research site in Fongoli, Senegal, between March 2005 and July 2006.

“There were hints that this behaviour might occur, but it was one time at a different site,” said Jill Pruetz, assistant professor of anthropology at Iowa State University, US.

“While in Senegal for the spring semester, I saw about 13 different hunting bouts. So it really is habitual.”

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Check out this movie at National Geographic.

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Genetic Breakthrough That Reveals the Differences Between Humans

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Scientists have discovered a dramatic variation in the genetic make-up of humans that could lead to a fundamental reappraisal of what causes incurable diseases and could provide a greater understanding of mankind.

The discovery has astonished scientists studying the human genome – the genetic recipe of man. Until now it was believed the variation between people was due largely to differences in the sequences of the individual ” letters” of the genome.

It now appears much of the variation is explained instead by people having multiple copies of some key genes that make up the human genome.

Until now it was assumed that the human genome, or “book of life”, is largely the same for everyone, save for a few spelling differences in some of the words. Instead, the findings suggest that the book contains entire sentences, paragraphs or even whole pages that are repeated any number of times.

The findings mean that instead of humanity being 99.9 per cent identical, as previously believed, we are at least 10 times more different between one another than once thought – which could explain why some people are prone to serious diseases.

The studies published today have found that instead of having just two copies of each gene – one from each parent – people can carry many copies, but just how many can vary between one person and the next.

The studies suggest variations in the number of copies of genes is normal and healthy. But the scientists also believe many diseases may be triggered by an abnormal loss or gain in the copies of some key genes.

Another implication of the finding is that we are more different to our closest living relative, the chimpanzee, than previously assumed from earlier studies. Instead of being 99 per cent similar, we are more likely to be about 96 per cent similar.

The findings, published simultaneously in three leading science journals by scientists from 13 different research centres in Britain and America, were described as ground-breaking by leading scientists.

independent uk

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Lizards Have Personalities Too!

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They may be cold-blooded, but some lizards have warm personalities and like to socialise, a new study shows.

A behavioural study reveals that lizards have different social skills: some are naturally inclined to join large groups while others eschew company altogether. The discovery of reptilian personality types could help ecologists better understand and model animal population dynamics, say the researchers involved.

NS

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First Bionic Woman Can Feel It When People Shake Her Prosthetic Hand

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It’s the stuff of science fiction: a prosthetic arm that can be moved just by thinking about it and that can feel heat and the pressure of a handshake. It became a reality for US Marine Claudia Mitchell two years after she lost her arm to a motorcycle, researchers said last week.

The bionic arm is controlled by rerouting nerves in Mitchell’s shoulder to healthy muscles in her chest. This targeted muscle reinnervation directs the signals once sent to the amputated arm to the robotic arm via surface electrodes that respond to Mitchell’s thoughts.

PhysOrg

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‘Spectrum of Empathy’ – Mirror Neurons Confirmed in Human Brain

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Ever wondered how some people can “put themselves into another person’s shoes” and some people cannot? Our ability to empathise with others seems to depend on the action of “mirror neurons” in the brain, according to a new study.

Mirror neurons, known to exist in humans and in macaque monkeys, activate when an action is observed, and also when it is performed. Now new research reveals that there are mirror neurons in humans that fire when sounds are heard. In other words, if you hear the noise of someone eating an apple, some of the same neurons fire as when you eat the apple yourself.

So-called auditory mirror neurons were known only in macaques. To determine if they exist in humans Valeria Gazzola, at the school of behavioural and cognitive neurosciences neuroimaging centre at the University of Groningen, the Netherlands, and colleagues, put 16 volunteers into functional magnetic resonance imaging (fMRI) scanners and observed their brains as they were played different noises.

The volunteers heard noises such as a sheet of paper being torn, or of someone crunching potato chips. Then the same subjects were scanned again, this time whilst tearing a piece of paper, or eating potato chips.

new scientist

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Meerkats Show Signs of Culture

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Meerkat pups do not learn how to eat dangerous animals such as scorpions on their own but are taught by adults, scientists have discovered.

Researchers found that adults bring dead animals to the youngest pups.

As pups get older, helpers disable live prey for them; finally they coax the youngsters to hunt for themselves.

Writing in the journal Science, the scientists suggest meerkats are only the second non-human animal species found to teach its young actively.

The only other clear demonstration of teaching behaviour in species other than Homo sapiens is, they say, the finding reported earlier this year that ants can help their fellows locate food.

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Mice Show Empathy For Fellow Rodents

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Mice appear to empathize with pain in other critters they’re familiar with, a capacity previously thought to exist only in higher primates.

When mice saw others they knew showing pain, they responded with signs of empathy, such as staying close by, according to a new study.

The mice seem hardwired to form a lower type of empathy called “emotional contagion,” said Jeffrey Mogil, a McGill University geneticist, who led the study appearing in Friday’s issue of the journal Science.

The contagious effect isn’t triggered by conscious kindness. It’s more like the way someone’s yawn prompts someone nearby to do the same.

cbc news

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“I’ve found God”, Says Man Who Cracked the Genome

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THE scientist who led the team that cracked the human genome is to publish a book explaining why he now believes in the existence of God and is convinced that miracles are real.

Francis Collins, the director of the US National Human Genome Research Institute, claims there is a rational basis for a creator and that scientific discoveries bring man “closer to God”.

His book, The Language of God, to be published in September, will reopen the age-old debate about the relationship between science and faith. “One of the great tragedies of our time is this impression that has been created that science and religion have to be at war,” said Collins, 56.

Sunday Times

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Semiconductor Brain: Nerve Tissue Interfaced With A Computer Chip

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For the first time, scientists at the Max-Planck Institute for Biochemistry in Martinsried near Munich coupled living brain tissue to a chip equivalent to the chips that run computers. The researchers under Peter Fromherz have reported this news in the online edition of the Journal of Neurophysiology (May 10, 2006).

Before informational input perceived by the mammalian brain is stored in the long-term memory, it is temporarily memorised in the hippocampus*. Understanding the function of the hippocampus as an important player in the memory process is a major topic of current brain research. Thin slices of this brain region provide the appropriate material to study the intact neural network of the hippocampus.

Methods commonly used in neurophysiology are invasive, restricted to a small number of cells or suffer from low spatial resolution. The scientists in Martinsried developed a revolutionary non- invasive technique that enables them to record neural communication between thousands of nerve cells in the tissue of a brain slice with high spatial resolution. This technique involves culturing razor-thin slices of the hippocampus region on semiconductor chips. These chips were developed in collaboration with Infineon Technologies AG and excel in their density of sensory transistors: 16384 transistors on an area of one square millimeter record the neural activity in the brain.

Science Daily

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Scientist Reverses Process of Cell Division

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Gary J. Gorbsky, Ph.D., a scientist with the Oklahoma Medical Research Foundation, has found a way to reverse the process of cell division.

The discovery could have important implications for the treatment of cancer, birth defects and numerous other diseases and disorders. Gorbsky’s findings appear in the April 13 issue of the journal Nature, one of the world’s leading scientific publications.

“No one has gotten the cell cycle to go backwards before now,” said Gorbsky, who holds the W.H. and Betty Phelps Chair in Developmental Biology at OMRF. “This shows that certain events in the cell cycle that have long been assumed irreversible may, in fact, be reversible.”

Cell division occurs millions of times each day in the human body and is essential to life itself. In the lab, Gorbsky and his OMRF colleagues were able to control the protein responsible for the division process, interrupt and reverse the event, sending duplicate chromosomes back to the center of the original cell, an event once thought impossible.

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Print me a heart and a set of arteries

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SITTING in a culture dish, a layer of chicken heart cells beats in synchrony. But this muscle layer was not sliced from an intact heart, nor even grown laboriously in the lab. Instead, it was “printed”, using a technology that could be the future of tissue engineering.

Gabor Forgacs, a biophysicist at the University of Missouri in Columbia, described his “bioprinting” technique last week at the Experimental Biology 2006 meeting in San Francisco. It relies on droplets of “bioink”, clumps of cells a few hundred micrometres in diameter, which Forgacs has found behave just like a liquid.

This means that droplets placed next to one another will flow together and fuse, forming layers, rings or other shapes, depending on how they were deposited. To print 3D structures, Forgacs and his colleagues alternate layers of supporting gel, dubbed “biopaper”, with the bioink droplets. To build tubes that could serve as blood vessels, for instance, they lay down successive rings containing muscle and endothelial cells, which line our arteries and veins. “We can print any desired structure, in principle,” Forgacs told the meeting.

New Scientist

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