Tag Archives: Life Science

Robot with Biological Brain

Life for Warwick’s robot began when his team at the University of Reading spread rat neurons onto an array of electrodes. After about 20 minutes, the neurons began to form connections with one another. “It’s an innate response of the neurons,” says Warwick, “they try to link up and start communicating.”

For the next week the team fed the developing brain a liquid containing nutrients and minerals. And once the neurons established a network sufficiently capable of responding to electrical inputs from the electrode array, they connected the newly formed brain to a simple robot body consisting of two wheels and a sonar sensor.
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At first, the young robot spent a lot of time crashing into things. But after a few weeks of practice, its performance began to improve as the connections between the active neurons in its brain strengthened. “This is a specific type of learning, called Hebbian learning,” says Warwick, “where, by doing something habitually, you get better at doing it.”
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“It’s fun just looking at it as a robot life form, but I think it may also contribute to a better understanding of how our brain works,” he says. Studying the ways in which his robot learns and stores memories in its brain may provide new insights into neurological disorders like Alzheimer’s disease.

Darwin’s Jellyfishes

Palau’s marine-lake jellyfish actually diverged very quickly from their common ancestor, the spotted jellyfish. Like other jellyfish, the spotted jellies are cnidarians, a scientific grouping that includes reef-building corals. The spotted jellyfish drift in Palau’s lagoon, zapping the occasional zooplankton with their stinging nettles and absorbing the sugary by-products of photosynthesizing algae living in their tissues.

Like many jelly species, the spotted jellyfish has a multi-stage life cycle. Adult males and females with the familiar bell-shaped bodies are called medusae, but you would not recognize very young jellyfish as jellyfish at all. After medusae release eggs and sperm into the water, fertilized eggs hatch as larvae that drift for a few days before attaching to solid objects, such as rocks. The larvae morph into polyps resembling tiny anemones. Polyps can bud off into more polyps or, when conditions are right, into new young medusae.
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the jellyfish do not “eat” algae. Like their lagoon ancestors, the jellyfish simply absorb their algae’s photosynthetic leftovers. The jellies get about three-fourths of their energy from algal excretions and the remainder from prey. In essence, the jellyfish are landlords that hunt a bit on the side.

The jellyfish-algae partnership did not originate in the lakes, either. Ancestral spotted jellyfish brought the arrangement with them. “Spotted jellyfish in the lagoon have basic behaviors that help ‘sun’ their algae,” Martin explains. “They move eastward in the morning. The lake jellies have adapted this migration to each individual lake. The most spectacular migration is in Jellyfish Lake.”

The jellies’ migration delicately balances time in the sun (to benefit their algae) and predator avoidance. The gelatinous masses of peanut-shaped Jellyfish Lake begin their day in the western basin. As the sun rises they pulsate eastward toward the rising sun—but not too far east, because the lakeshore is covered with jellyfish-eating anemones. The jellies stop swimming east when they hit the shade cast by mangrove trees lining the shore.
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At nightfall the jellies switch to a vertical migration. Jellyfish Lake reaches depths of 100 feet, but only the top 45 feet contain oxygen. The bottom is a toxic vat of hydrogen sulfide. Bacteria do a brisk business at the interface, metabolizing both the oxygen above and hydrogen sulfide below. Every night the jellies bob up and down from the surface to the bacterial layer. Besides helping the jellyfish stay in place, dipping down treats the jellies’ algae to a midnight snack of nutrients excreted by the microbial masses.

Very Cool.

Gram-negative Bacteria Defy Drug Solutions

Deadly bacteria defy drugs, alarming doctors by Mary Engel

Acinetobacter doesn’t garner as many headlines as methicillin-resistant Staphylococcus aureus, the dangerous superbug better known as MRSA. But a January report by the Infectious Diseases Society of America warned that drug-resistant strains of Acinetobacter baumannii and two other microbes — Pseudomonas aeruginosa and Klebsiella pneumoniae — could soon produce a toll to rival MRSA’s.

The three bugs belong to a large category of bacteria called “gram-negative” that are especially hard to fight because they are wrapped in a double membrane and harbor enzymes that chew up many antibiotics. As dangerous as MRSA is, some antibiotics can still treat it, and more are in development, experts say.

But the drugs once used to treat gram-negative bacteria are becoming ineffective, and finding effective new ones is especially challenging.
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For the most part, gram-negative bacteria are hospital scourges — harmless to healthy people but ready to infect already-damaged tissue. The bacteria steal into the body via ventilator tubes, catheters, open wounds and burns, causing pneumonia, urinary tract infections, and bone, joint and bloodstream infections.

Pseudomonas is widely found in soil and water, and rarely causes problems except in hospitals.

Why Does Hair Turn Grey as We Age?

A team of European scientists have learned why our hair turns gray as we age. Despite the notion that gray hair is a sign of wisdom, these researchers show that going gray is caused by a massive build up of hydrogen peroxide due to wear and tear of our hair follicles. The peroxide winds up blocking the normal synthesis of melanin, our hair’s natural pigment.

“Not only blondes change their hair color with hydrogen peroxide,” said Gerald Weissmann, MD, Editor-in-Chief of The FASEB Journal. “All of our hair cells make a tiny bit of hydrogen peroxide, but as we get older, this little bit becomes a lot. We bleach our hair pigment from within, and our hair turns gray and then white. This research, however, is an important first step to get at the root of the problem, so to speak.”

The researchers made this discovery by examining cell cultures of human hair follicles. They found that the build up of hydrogen peroxide was caused by a reduction of an enzyme that breaks up hydrogen peroxide into water and oxygen (catalase). They also discovered that hair follicles could not repair the damage caused by the hydrogen peroxide because of low levels of enzymes that normally serve this function (MSR A and B). Further complicating matters, the high levels of hydrogen peroxide and low levels of MSR A and B, disrupt the formation of an enzyme (tyrosinase) that leads to the production of melanin in hair follicles. Melanin is the pigment responsible for hair color, skin color, and eye color. The researchers speculate that a similar breakdown in the skin could be the root cause of vitiligo.

Weissmann added. “This study is a prime example of how basic research in biology can benefit us in ways never imagined.”

See full press release

Scientists Say Biotechnology Seed Companies Prevent Research

Crop Scientists Say Biotechnology Seed Companies Are Thwarting Research

Biotechnology companies are keeping university scientists from fully researching the effectiveness and environmental impact of the industry’s genetically modified crops, according to an unusual complaint issued by a group of those scientists.
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The researchers, 26 corn-insect specialists, withheld their names because they feared being cut off from research by the companies. But several of them agreed in interviews to have their names used.

The problem, the scientists say, is that farmers and other buyers of genetically engineered seeds have to sign an agreement meant to ensure that growers honor company patent rights and environmental regulations. But the agreements also prohibit growing the crops for research purposes.

So while university scientists can freely buy pesticides or conventional seeds for their research, they cannot do that with genetically engineered seeds. Instead, they must seek permission from the seed companies. And sometimes that permission is denied or the company insists on reviewing any findings before they can be published, they say.

Such agreements have long been a problem, the scientists said, but they are going public now because frustration has been building.

This is not acceptable. Regulators need to put safety above politically connected powerful groups. The bigger problem is we keep electing people more interested in who gives than money than the public interest. But part of the dynamic is embarrassing those that subvert the public good to reward those providing the politicians money. By shining light on what is being done the abuses are often reduced a bit.

Darwin’s Beetles Still Producing Surprises

As part of National Science Foundation-funded research on the evolution of male dimorphism in insects, biology professors J. Mark Rowland, UNM, and Douglas J. Emlen, UM, were surprised to find that many species of beetles are capable of producing not only two, but three different types of males.

The sex lives of animals is known to be complicated business. Where competition in mating is particularly intense, many kinds of animals produce enlarged weapons that function in male combat and utilize alternative tactics in deploying them. Such exaggerated structures include horns in dinosaurs and deer, and tusks in elephants and walrus.

Elaborate male weapons are also known to occur in many types of insects. Now it appears, as the research of Rowland and Emlen illustrates, that male weaponry and alternative mating tactics can be much more complex in the lives of beetles than previously imagined.

“We discovered a novel mating system in which the individual males of various species of beetles have the capacity to express one of three alternative morphologies,” said Rowland. “In many dung beetles , smaller males are unlikely to prevail in direct contests with alpha males. These beta males develop disproportionally smaller horns and employ alternative, less aggressive, reproductive tactics.

“The trimorphic species reported here have alpha, beta and gamma (completely hornless) male – three qualitatively distinct forms. A mating strategy with three such tactics implies considerable complexity, but may actually involve operational rules reminiscent of the old rock, paper, scissors game.”
Continue reading →

Bug of the Week: Leaf-footed Bug

Photo of leaf-footed bug by Roberta

The Growing With Science Blog by Roberta, an entomologist, is full of interesting posts on bugs and more. For example – Bug of the Week: Leaf-footed Bug

We were doing a bit of yard work when we came across this leaf-footed bug. These insects get their name from the leaf-like flanges on their hind legs.Note the light-colored zig-zag marking across the middle of its back.

Leaf-footed bugs have sucking mouthparts and sometimes feed of fruit such as cactus fruit, oranges or peaches. Although we do have citrus, I think this one is a visitor from our neighbors’ yard. Our neighbors have a pomegranate bush. Pomegranates are one of the leaf-footed bugs’ favorite foods.

Like many of their relatives, these true bugs can give off an odor when handled.

🙂 I was adding in some related links and the first one, I was adding, Backyard Wildlife: Great Spreadwing Damselfly, Roberta had commented on to let me know it was a Great Spreadwing Damselfly. It is a small web.

Evolution, Methane, Jobs, Food and More

Photo from May 2005 by NASA’s Mars Exploration Rover Spirit as the Sun sank below the rim of Gusev crater on Mars.

Science Friday is a great National Public Radio show. The week was a great show covering Antimicrobial Copper, Top Jobs for Math and Science, Human-Driven Evolution, Methane On Mars, Fish with Mercury and more. This show, in particular did a great job of showing the scientific inquiry process in action.

“Fishing regulations often prescribe the taking of larger fish, and the same often applies to hunting regulations,” said Chris Darimont, one of the authors of the study. “Hunters are instructed not to take smaller animals or those with smaller horns. This is counter to patterns of natural predation, and now we’re seeing the consequences of this management.” Darimont and colleagues found that human predation accelerated the rate of observable trait changes in a species by 300 percent above the pace observed within purely natural systems, and 50 percent above that of systems subject to other human influences, such as pollution

Very interesting stuff, listen for more details. A part of what happens is those individuals that chose to focus on reproducing early (instead of investing in growing larger, to reproduce later) are those that are favored (they gain advantage) by the conditions of human activity. I am amazed how quickly the scientists says the changes in populations are taking place.

And Methane On Mars is another potentially amazing discovery. While it is far from providing proof of live on Mars it is possibly evidence of life on Mars. Which would then be looked back on as one of the most important scientific discoveries ever. And in any even the podcast is a great overview of scientists in action.

This week astronomers reported finding an unexpected gas — methane — in the Martian atmosphere. On Earth, a major source of methane is biological activity. However, planetary scientists aren’t ready to say that life on Mars is to blame for the presence of the gas there, as geochemical processes could also account for the finding. The find is intriguing especially because the researchers say they have detected seasonal variations of methane emissions over specific locations on the planet.

Martian Methane Reveals the Red Planet is not a Dead Planet
The Mars Methane Mystery: Aliens At Last?

Soil Mineral Degrades the Nearly Indestructible Prion

Warped pathogens that lack both DNA and RNA, prions are believed to cause such fatal brain ailments as chronic wasting disease (CWD) in deer and moose, mad cow disease in cattle, scrapie in sheep and Creutzfeldt-Jakob disease in humans. In addition to being perhaps the weirdest infectious agent know to science, the prion is also the most durable. It resists almost every method of destruction from fire and ionizing radiation to chemical disinfectants and autoclaving, which reduce prion infectivity but fail to completely eliminate it.

Other studies have shown that prions can survive in the soil for at least three years, and that soil is a plausible route of transmission for some animals, says Joel Pedersen, a UW-Madison environmental chemist. “We know that environmental contamination occurs in deer and sheep at least,” he notes.

Prion reservoirs in the soil, Pedersen explains, are likely critical links in the chain of infection because the agent does not appear to depend on vectors — intermediate organisms like mosquitoes or ticks — to spread from animal to animal.

That the birnessite family of minerals possessed the capacity to degrade prions was a surprise, Pedersen says. Manganese oxides like birnessite are commonly used in such things as batteries and are among the most potent oxidants occurring naturally in soils, capable of chemically transforming a substance by adding oxygen atoms and stripping away electrons. The mineral is most abundant in soils that are seasonally waterlogged or poorly drained.

full press release

Moth Jams Bat Sonar

Superloud moth jams bat sonar

A gray moth with orange highlights called Bertholdia trigona “goes berserk,” making lots of noise above the range of human hearing when a hunting bat approaches, says William Conner of Wake Forest University in Winston-Salem, N.C. Bats rely on their natural sonar to locate flying moths in the dark, but in a lab setup, the bats rarely managed to nab a loud moth.

When researchers disabled the moth’s noisemaking organs, though, bats caught the moths in midair with ease, Conner reported at the annual meeting of the Society for Integrative and Comparative Biology.

Conner says the work is “the first example of any prey item that jams biological sonar.” Conference attendee David Yager of the University of Maryland in College Park says Conner’s experimental paradigm is “very strong, and I do think he has documented jamming by a species of moth.”

Insect-hunting bats and their moth prey have become a classic in the study of evolutionary arms races, Conner says. “This is warfare … The first counter-adaptation is that the insects developed ears.”
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Jamming isn’t the only possible explanation for moth noises, he said. An explosive clicking sound coming back out of the night might startle a bat just a split-second long enough for the moth to get away.