Category Archives: Life Science

Asymmetrical Brains Aid Multi-tasking

Asymmetrical brains help fish (and us) to multi-task:

In the animal world, the ability to multi-task is a matter of life and death. Many species must be ever-watchful for food, while simultaneously looking out for predators who would view them in the same way Like too many open applications that slow down a computer, these multiple tasks compete for the brain’s finite resources. Those who survive life’s challenges are those with an edge at efficiently dealing with multiple demands.

One way of doing this is to use parallel processing – to delegate different parts of a problem to different pieces of hardware. This is exactly the situation found in the human brain, with two asymmetric hemispheres associated with different mental abilities. And this ‘lateralisation’ is not unique to us, but seems to be present in all back-boned animals, from fish to apes. An explanation for this asymmetry now becomes obvious – it may allow animals to multi-task, acting as a sort of cerebral division of labour.
…
In these cases, regardless of parallel processing power, an asymmetric brain is clearly a disadvantage. The two scientists believe that the tipping point between these pros and cons comes when an animal has to perform difficult mental tasks.

Other studies have shown that asymmetrical brains endow wild chimpanzees with superior termite-fishing skills, and (equally wild) human children with better mathematical and verbal abilities than their classmates. It may be that over the course of evolution, our brain’s halves started to work together more effectively as they became more different and specialised. It is ironic and sad then, that the opposite seems to hold true for the divergence of human cultures.

Move over MRSA, C.diff is Here

Clostridium difficile (C.diff), a bacteria, is increasingly posing health risk. Rising Foe Defies Hospitals’ War On ‘Superbugs’

Even as hospitals begin to get control of other drug-resistant infections such as MRSA, a form of staph, rates of C. diff are rising sharply, and a recent, more virulent strain of the bug is causing more severe complications. The Centers for Disease Control and Prevention estimates there are 500,000 cases of C. diff infection annually in the U.S., contributing to between 15,000 and 30,000 deaths. That’s up from roughly 150,000 cases in 2001.
…
Many patients get C. diff infections as an unintended consequence of taking antibiotics for other illnesses. That’s because bacteria normally found in a person’s intestines help keep C. diff under control, allowing the bug to live in the gut without necessarily causing illness. But when a person takes antibiotics, both bad and good bacteria are suppressed, allowing drug-resistant C. diff to grow out of control.
…
Only 3% to 5% of healthy, non-hospitalized adults carry C. diff in their gut, but that rate is much higher in hospitals and nursing homes, where carriers can spread the bacteria to others. Studies at several hospitals in recent years have shown that 20% or more of inpatients were colonized with C. diff, and a 2007 study of 73 long-term-care residents showed 55% were positive for C. diff. Even though the majority had no symptoms of disease, spores on the skin of asymptomatic patients were easily transferred to the investigators’ hands.

Ancient Ants

Blind “Ant From Mars” Found in Amazon

An ant so unlike all other living ants that it was given an extraterrestrial name has been discovered in the Amazon rain forest, biologists announced today. The tiny new species is the only known surviving member of an ant lineage that separated from the main family more than a hundred million years ago, DNA analysis revealed.

The pale, eyeless ant appears to be adapted to living underground, possibly surfacing at night to forage. Its long mandibles suggest that the 0.08-inch-long (2-millimeter-long) animal is a predator, most likely of soft-bodied creatures such as termite larvae.

Christian Rabeling, a graduate student at the University of Texas in Austin, found a single specimen of the new species, thought to be a worker ant, in tropical soils near Manaus, Brazil. Rabeling’s team named the new creature Martialis heureka—”Martialis” means “of Mars
…
The new species’ genes suggest that it broke away from the main ant family before the origin of all other living ant groups, which include 20 subfamilies that together contain more than 12,000 species.

Tardigrades In Space (TARDIS)

Research showing that Tardigrades (Water Bears) can survive in space without protection has been in the news lately. There is a blog with a few posts from the research team (only from last year unfortunately): Tardigrades In Space (TARDIS). They chose not to publish the research in an open access fashion, unfortunately.

Tiny Critters Survive Space

These small, segmented animals not only survived a 12-day orbital expedition, some members of the community felled by solar radiation actually recovered upon their return to Earth.

“How these animals were capable of reviving their body … remains a mystery,” said lead researcher Ingemar JÃ¶nsson, with Sweden’s Kristianstad University, who writes about the discovery in this week’s issue of Current Biology.
…
Most of the 3,000 creatures not only survived, but they went on to reproduce once they came back to Earth. About 12 percent of the animals exposed to ultraviolet radiation revived after being put back in water, a puzzling find since researchers presume the sterilizing rays broke down the tardigrades’ DNA. “This type of radiation cuts the DNA strand effectively in most organisms”

North American Fish Threatened

North American Fish Under Threat

Nearly 40 percent of fish species in North America are imperiled, according to a new survey by fish experts, the U. S. Geological Survey, and the American Fisheries Society, up 92 percent from the last survey done in 1989.
…
No single cause explains the ongoing fish losses, Taylor and others agree. Habitat loss, invasive species, diseases, dams, and water contaminants all contribute.

“Fish are kind of canaries in the coal mine,” said Howard Jelks of the USGS and lead author of the report, published in Fisheries. “If you change the water to something that’s not able to support these fish, it’s also not going to be as high quality for recreating, for eating the fish out of these streams, for drawing water that’s ultimately used for drinking, or for other things.”

Active Amish Avoid Obesity

Lessons from the Amish: We’re not doomed to obesity

Four years ago we discovered that the Amish maintained super-low obesity levels despite eating a diet high in fat, calories and refined sugar. They key was their level of physical activity — men averaged 18,000 steps a day, women 14,000. That’s monumental compared to the paltry couple of thousand or so most of us eke out in a day.
…
A recent study revealed even more about the Old Order Amish: They maintain low obesity levels despite having a gene variation that makes them susceptible to obesity. The secret here? You guessed it — lots of physical activity.

Study Conclusions: “Our results strongly suggest that the increased risk of obesity owing to genetic susceptibility by FTO variants can be blunted through physical activity. These findings emphasize the important role of physical activity in public health efforts to combat obesity, particularly in genetically susceptible individuals.”

Sometimes the simple explanation is worth paying attention to. Add lack of activity to eating more (Obesity Epidemic Explained – Kind Of: 1970 Americans ate an average of 2170 calories per day in 2000 they ate an average of 2700) and it seems like it is logical we would gain weight due to these two factors.

Do Dolphins Sleep?

Do dolphins sleep?, MIT:

Dolphins do sleep, but not quite in the same way that people do. They sleep with one half of the brain at a time and with one eye closed. Dolphins rest this way on and off throughout the day, switching which side of the brain they shut down. During these periods, everything inside the dolphin slows down, and the mammal moves very little.

Algorithmic Self-Assembly

Paul Rothemund, scientist at Cal Tech, provides a interesting look at DNA folding and DNA based algorithmic self-assembly. In the talk he shows the promise ahead for using biological building blocks using DNA origami — to create tiny machines that assemble themselves from a set of instructions.

Algorithmic Self-Assembly of DNA Sierpinski Triangles, PLoS paper.

I posted a few months ago about how you can participate in the protein folding, with the Protein Folding Game.

8 Percent of the Human Genome is Old Virus Genes

In Our Genes, Old Fossils Take On New Roles

It turns out that about 8 percent of the human genome is made up of viruses that once attacked our ancestors. The viruses lost. What remains are the molecular equivalents of mounted trophies, insects preserved in genomic amber, DNA fossils.

The thousands of human endogenous retroviruses, or HERVs, sketch a history of rough times during the 550 million years of vertebrate evolution. The best-preserved one, HERV-K113, probably arrived less than 200,000 years ago, long after human beings and chimpanzees diverged from a common ancestor.

But these retroviruses are more than just curiosities. They are some of the most important enemies we ever had. They helped mold the immune system that is one of the evolutionary marvels of life on Earth.

I must say there is tons of amazing stuff I learn about but I still find retroviruses amazing.

General Biology Berkeley Course Webcast

General Biology Course at University of California – Berkeley, Fall 2007. Instructors John Forte, R Fischer and R Malkin. “General introduction to cell structure and function, molecular and organism genetics, animal development, form and function. Intended for biological sciences majors, but open to all qualified students.” A great service from Berkeley with video and audio… Topics include: Macromolecules structure and function, How cells function-an introduction to cellular metabolism and biological catalysts, Microbes – Viruses, Bacteria, Plasmids, Transposons and Homeostasis: The body’s defenses.