Category Archives: Life Science

Gene Study Finds Cannibal Pattern

Deep in the recesses of the human heart, lurking guiltily beneath the threshold of consciousness, there may lie a depraved craving — for the forbidden taste of human flesh. The basis for this morbid accusation, made by a team of researchers in London, is a genetic signature, found almost worldwide, that points to a long history of cannibalism.

The signature is one that protects the bearer from infection by prions, proteins that can be transmitted in infected meat and attack the nerve cells of the brain. Prions can be acquired from eating infected animals, as in the case of the mad cow disease that in 1996 spread to people in England, but they spread even more easily through eating infected humans.
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The researchers then examined DNA from various ethnic groups around the world and found that all but one, the Japanese, carried the protective signature to some degree, and that the Japanese are protected by a different signature in the same gene.

Various genetic tests showed that the protective genes could not be there by chance, but were a result of natural selection. This implies that human populations in the past must have been exposed to some form of prion disease, the researchers say.

Effect of People on Other Species

We’ve Seen The Future, And It Is Us:

Human habitation has been, and is increasingly, playing a direct role not only in the extinction of species, but in their evolution. By our own actions, we may be accompanied into the future by ever more diverse pests and pathogens, and may leave behind what we value most—elephants, tigers, and others of the earth’s great megabeasts.
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Where we have industrialized agriculture, weeds have evolved to chemically mimic our crops to avoid the herbicide. Insect pests have evolved resistance to DDT and to the pesticides that have followed. We have countered with genetically engineered crops. Already there are insect species resistant to the defenses of those crops. When we add new species of crops, insects in turn rapidly switch to those.

Midichloria mitochondrii

Use the force, bacteria (sadly, the site broke the link so our link was removed):

When his team took a tick apart to look for the new bug, they found it in the ovaries. And, when they looked closely at electron micrographs of infected ovarian tissues, they could see that the microbes were intracellular – living not in the cytoplasm of tick ova, but within their mitochondria.

“We’d never seen anything like this before,” Lo says, as he opens the image files on his laptop on a rainy afternoon in Sydney. “They seem to get in between the inner and outer mitochondrial membranes and eat the mitochondria up. In the end you’ve just got this empty sack.”
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says he wasn’t aware of any other bacteria that live inside mitochondria. “It’s pretty surprising to see a bacterial species living inside the mitochondrion, which itself was a bacterium,”

Scientists Knock-out Prion Gene in Cows

Scientists Announce Mad Cow Breakthrough by Rick Weiss

Scientists said yesterday that they have used genetic engineering techniques to produce the first cattle that may be biologically incapable of getting mad cow disease. The animals, which lack a gene that is crucial to the disease’s progression, were not designed for use as food. They were created so that human pharmaceuticals can be made in their blood without the danger that those products might get contaminated with the infectious agent that causes mad cow.

That agent, a protein known as a prion (pronounced PREE-on), can cause a fatal human ailment, variant Creutzfeldt-Jakob disease, if it gets into the body. More generally, scientists said, the animals will facilitate studies of prions, which are among the strangest of all known infectious agents because they do not contain any genetic material.
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Prions remain poorly understood, but experiments suggest that it takes just one bad one to ruin a brain. That’s because a badly folded prion in the brain can strong-arm normal, nearby prions, turning good prions bad.

Antibiotic resistance: How do antibiotics kill bacteria?

Many, if not most, antibiotics act by inhibiting the events necessary for bacterial growth. Some inhibit DNA replication, some, transcription, some antibiotics prevent bacteria from making proteins, some prevent the synthesis of cell walls, and so on. In general, antibiotics keep bacteria from building the parts that are needed for growth.
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It seems funny to think that not growing can be a mechanism for survival. But if you’re a bacteria, and you can hang around long enough in an inactive, non-growing state, eventually your human host will stop taking antibiotics, they will disappear from your environment and you can go back to growing.

Bald Eagle Carry a Fish Over Manhattan

Famed NYC hawk sees bald eagle soar by (page deleted by AP)

A bald eagle carries a fish in its talons over New York City’s Central Park, Wednesday, Dec. 27, 2006. The eagles flight didn’t go unnoticed by Pale Male, the famed red-tailed hawk of Central Park, who was perched on the 22nd floor of the Beresford apartment building as the eagle flew by. “Pale Male usually sits there sort of relaxed, but he sat up straight when he saw the bald eagle,” said Lincoln Karim

via: AP: Bald eagle, dangling a big fish in its talons, over NY City

Brain Research on Sea Slugs

How many genes does it take to learn? Lessons from sea slugs

“In the human brain there are a hundred billion neurons, each expressing at least 18,000 genes, and the level of expression of each gene is different,” said Moroz, who is affiliated with UF’s Evelyn F. and William L. McKnight Brain Institute and the UF Genetics Institute. “Understanding individual genes or proteins is important, but this is a sort of molecular alphabet. This helps us learn the molecular grammar, or a set of rules that can control orchestrated activity of multiple genes. If we are going to understand memory or neurological disease at the cellular level, we need to understand the rules.”

Scientists also analyzed 146 human genes implicated in 168 neurological disorders, including Parkinson’s and Alzheimer’s diseases, and genes controlling aging and stem-cell differentiation. They found 104 counterpart genes in Aplysia, suggesting it will be a valuable tool for developing treatments for neurodegenerative diseases.

Robot Heading for Antarctic Dive

Robot heading for Antarctic dive, BBC News:

Isis, the UK’s first deep-diving remotely operated vehicle (ROV), will be combing the sea-bed in the region in its inaugural science mission. Researchers hope to uncover more about the effects of glaciers on the ocean floor, and also find out about the animals that inhabit these waters. The mission begins in mid-January and will last for about three weeks. While the scientists and engineers begin their long journey to the Antarctic at the start of January, Isis left the UK shores in November and has only just arrived at its destination.
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Ten kilometres of cable connect it to its “mother ship”, allowing scientists to control the vehicle and receive the data it collects in real-time. On the ROV, Mr Mason said, were lights, cameras to produce high-quality video and still pictures, sonars for acoustic navigation and imaging, and two remotely controlled manipulator arms to collect samples or place scientific instruments on the sea-bed.
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“We are hoping to see a whole bunch of large creatures such as star fish, sea cucumbers, sea fans, sea pens, etc, that inhabit the deep shelf slope and abyssal depths.” He added: “Essentially no-one has explored Antarctica using a ROV at these depths.”

Single Gene Could Lead to Long Life

Single Gene Could Lead to Long Life, Better Mental Function by Charles Q. Choi:

The CETP gene variant makes cholesterol particles in the blood larger than normal. The researchers suggest smaller particles can more readily lodge in the lining of blood vessels, leading to fatty buildups, which are a risk factor for heart attacks and strokes.

Whether or not this gene variant protects the brain by preventing this buildup, or through some other mechanism, remains uncertain, says Barzilai. Future research should also investigate whether this gene has an effect on dementia associated with Alzheimer’s disease, says pathologist and human geneticist George Martin at the University of Washington.

Pharmaceutical companies are currently developing drugs that mimic the effect of this gene variant, says Barzilai. Unfortunately, one known as torcetrapib, manufactured by Pfizer, was pulled in December due to increased death and heart problems among study subjects, “but others in development aren’t seeing that, so it might just have been a problem with that drug,”

Smallest Known Living Organisms Found – 200 nanometers

Shotgun sequencing finds nanoorganisms by Robert Sanders:

Once Baker had found gene segments (ribosomal RNA) from three Archaea, he was able to fish the microbes out of the slime soup and found that they were extremely small, around 200 nanometers in diameter, the size of large viruses. Bacteria average about five times this diameter. These therefore could be the smallest organisms ever found, though Baker needs to culture them before confirming this. Because they’re so small, however, they may not be free-living.

“We’re not sure they can live independently, whether they have enough genes to fend for themselves, but instead are symbiotic with another organism or are feeding off another organism,” Baker said. Baker now is trying to find the right conditions for these Archaea to thrive in a culture dish. For now, he has dubbed them ARMAN-1, -2 and -3, for Archaeal Richmond Mine Acidophilic Nanoorganisms.