Category 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.

CDC: Reduce Salt in Your Diet

USA Center for Disease Control: Application of Lower Sodium Intake Recommendations for Adults, 1999-2006 study

In 2005-2006, an estimated 29% of U.S. adults had hypertension (i.e., high blood pressure), and another 28% had prehypertension. The estimated average intake of sodium for those in the United States over 2 years old was 3,436 mg/day while the U.S. Department of Health and Human Services and U.S. Department of Agriculture recommended adults should consume no more than 2,300 mg/day of sodium (equal to approximately 1 tsp of salt), but those in specific groups (i.e., all persons with hypertension, all middle-aged and older adults, and all blacks) should consume no more than 1,500 mg/day of sodium (69% of U.S. adults should consume no more than !,500 mg/day). There is substantial evidence linking greater sodium intake to higher blood pressure.

Sodium reduction is recommended for persons with hypertension and as a first line of intervention for persons with prehypertension. Public health actions to reduce sodium intake likely will include reducing the sodium content of processed foods; encouraging consumption of more low-sodium foods, such as fruits and vegetables; and providing more relevant information about sodium in food labeling.

The current daily percentage value for sodium in the nutrition facts panel of packaged foods is based on a previous federal guideline of 2,400 mg/day and is likely to mislead the majority of consumers, for whom the 1,500 mg/day limit is applicable.

Why People Often Get Sicker When They’re Stressed

Researchers at UT Southwestern Medical Center identified a receptor, known as QseE, which resides in a diarrhea-causing strain of E coli. The receptor senses stress cues from the bacterium’s host and helps the pathogen make the host ill. A receptor is a molecule on the surface of a cell that docks with other molecules, often signaling the cell to carry out a specific function.

Dr. Vanessa Sperandio, associate professor of microbiology at UT Southwestern and the study’’ senior author, said QseE is an important player in disease development because the stress cues it senses from a host, chiefly epinephrine and phosphate, are generally associated with blood poisoning, or sepsis.

“Patients with high levels of phosphate in the intestine have a much higher probability of developing sepsis due to systemic infection by intestinal bacteria,” Dr. Sperandio said. “If we can find out how bacteria sense these cues, then we can try to interfere in the process and prevent infection.”

Millions of potentially harmful bacteria exist in the human body, awaiting a signal from their host that it’s time to release their toxins. Without those signals, the bacteria pass through the digestive tract without infecting cells. What hasn’t been identified is how to prevent the release of those toxins.

“There’s obviously a lot of chemical signaling between host and bacteria going on, and we have very little information about which bacteria receptors recognize the host and vice versa,” Dr. Sperandio said. “We’re scratching at the tip of the iceberg on our knowledge of this.”

“When people are stressed they have more epinephrine and norepinephrine being released. Both of these human hormones activate the receptors QseC and QseE, which in turn trigger virulence. Hence, if you are stressed, you activate bacterial virulence.” Dr. Sperandio said the findings also suggest that there may be more going on at the genetic level in stress-induced illness than previously thought.

“The problem may not only be that the stress signals are weakening your immune system, but that you’re also priming some pathogens at the same time,” she said. “Then it’s a double-edged sword. You have a weakened immune system and pathogens exploiting it.”

Previous research by Dr. Sperandio found that phentolamine, an alpha blocker drug used to treat hypertension, and a new drug called LED209 prevent QseC from expressing its virulence genes in cells. Next she will test whether phentolamine has the same effect on QseE.

Full press release: Researchers probe mechanisms of infection

Nearly Half of Adults in the USA Don’t Know How Long it Takes the Earth to Circle the Sun

Questions:

How long does it take for the Earth to revolve around the Sun?
Did the earliest humans and dinosaurs live on the earth at the same time?
What percent of the Earth’s surface that is covered with water?

According to the national survey commissioned by the California Academy of Sciences: only 53% of adults know how long it takes for the Earth to revolve around the Sun; only 59% of adults know that the earliest humans and dinosaurs did not live at the same time; only 47% of adults can roughly approximate the percent of the Earth’s surface that is covered with water. Only 21% of adults answered all three questions correctly. I sure hope readers of this blog do much better than that.

Despite the fact that access to fresh water is likely to be one of the most pressing environmental issues over the coming years, less than 1% of U.S. adults know what percent of the planet’s water is fresh (the correct answer is 3%).

Answers: Continue reading →

Continuing Bee Colony Collapse Disorder

Photo of a bee

‘I do everything… the bees still die’

The use of the term colony collapse disorder has been criticised by some scientists and other experts who say that it’s often an excuse for poor beekeeping. David sighs heavily.

“Well… I don’t abuse my bees, I kinda take offence at that, when we transport them we take great pains to make sure they arrive safely, to make sure they have water. It’s totally unexplained.

“That’s the frustrating part. There’s no reason that these bees here should be in this shape, just three months ago they were beautiful bees, they were large thriving colonies, and to have them dwindle down to one or two or frames of bees is beyond comprehension as far as I’m concerned.”

But despite the disappearance of his bees, and the lack of clarity about what’s causing it, David remains an optimist. He points to a small discreet emblem on the side of his pickup truck, a hieroglyph of an ancient bee.

“That little hieroglyph there is Egyptian it stands for a beekeeper or bees. It’s an ancient craft; it’s been around a long time. The bees will endure.”

Photo by Justin Hunter

Cactus Eating Bull Saving Kenyan Drylands

Cactus eating bull saves Kenyan drylands

Cows are playing an important role in land restoration in Baringo by eating up the invasive prickly pear cactus a nasty invasive plant that is destroying the drylands. It’s not obvious at all for cows to eat this thorny cactus, but Murry Roberts and his wife Elizabeth Meyerhoff told me about an amazing project that their organization, RAE (Rehabilitation of Arid Environments) has been working on. A few years ago they discovered that a local farmer had a bull that not only ate the nasty exotic thorny ugly, plant, but also taught other cows to go for it too.
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During the drought of 1999 – 2000 grassy fields were reduced to bare earth and cows had nothing left to eat were dying of starvation leading to widespread famine. The story goes that one farmer persuaded his bull to eat the leaves after he had burned off the thorns. Opuntia are 80% water and if one can get past the thorns, the plant is quite nutritious . The other starving cows watched the bull and then followed suit thus saving the herd and the farmer who has never looked back. The thorns are burnt off using wood from another nasty invasive species, Prosopis juliflora – making this an eco-friendly project all round.

Scientists Target Bacteria Where They Live

Scientists Learning to Target Bacteria Where They Live

Scientists have learned that bacteria that are vulnerable when floating around as individual cells in what is known as their “planktonic state” are much tougher to combat once they get established in a suitable place — whether the hull of a ship or inside the lungs — and come together in tightly bound biofilms. In that state, they can activate mechanisms like tiny pumps to expel antibiotics, share genes that confer protection against drugs, slow down their metabolism or become dormant, making them harder to kill.

The answer, say researchers, is to find substances that will break up biofilms.
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Melander said “a throwaway sentence in an obscure journal” — the Bulletin of the Chemical Society of Japan — gave them another clue. They isolated a compound from the sponge that disperses biofilms and figured out how to synthesize it quickly and cheaply.
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But dispersing biofilms without understanding all the ramifications could be a “double-edged sword,” Romeo warned, because some bacteria in a biofilm could wreak worse havoc once they disperse.

“Simply inducing biofilm dispersion without understanding exactly how it will impact the bacterium and host could be very dangerous, as it might lead to spread of a more damaging acute infection,” he said.

Resurrection of the Human IRGM Gene

Interesting open access paper on Death and Resurrection of the Human IRGM Gene. Author summary:

The IRG gene family plays an important role in defense against intracellular bacteria, and genome-wide association studies have implicated structural variants of the single-copy human IRGM locus as a risk factor for Crohn’s disease. We reconstruct the evolutionary history of this region among primates and show that the ancestral tandem gene family contracted to a single pseudogene within the ancestral lineage of apes and monkeys.

Phylogenetic analyses support a model where the gene has been “dead” for at least 25 million years of human primate evolution but whose ORF became restored in all human and great ape lineages. We suggest that the rebirth or restoration of the gene coincided with the insertion of an endogenous retrovirus, which now serves as the functional promoter driving human gene expression. We suggest that either the gene is not functional in humans or this represents one of the first documented examples of gene death and rebirth.

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.

Macropinna Microstoma: Fish with a Transparent Head

That is a pretty awesome fish. The eyes were believed to be fixed in place and seemed to provide only a “tunnel-vision” view of whatever was directly above the fish’s head. A new paper by Bruce Robison and Kim Reisenbichler shows that these unusual eyes can rotate within a transparent shield that covers the fish’s head. This allows the barreleye to peer up at potential prey or focus forward to see what it is eating.

Deep-sea fish have adapted to their pitch-black environment in a variety of amazing ways. Several species of deep-water fishes in the family Opisthoproctidae are called “barreleyes” because their eyes are tubular in shape. Barreleyes typically live near the depth where sunlight from the surface fades to complete blackness. They use their ultra-sensitive tubular eyes to search for the faint silhouettes of prey overhead.

Full press release