Category Archives: Life Science

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.

Batfish Key to Keeping Reefs Clean

Batfish may come to Great Barrier Reef’s rescue by Catherine Brahic:

Neither species was able to make a dent in the damaging algae. Nor did any of the remaining 41 herbivorous fish found in the area make much of a difference. Instead, the researchers found that a rare batfish, Platax pinnatus, moved in. The team was surprised to see the batfish act this way, as they usually feed on plankton and invertebrates on the sea bed. “In five days the batfish had halved the amount of weed. In eight weeks it was completely gone and the coral was free to grow unhindered,”
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Batfish are vulnerable because of their large size, which makes them attractive to spear fishers, and because their young depend on coastal mangroves which are in decline in many areas. For now, they are one of the last populations apparently capable of reversing the fate of coral reefs that have been damaged by overfishing. Already, the reef has all but lost two major weed-mowers: dugongs and green turtles.

Which relates to a story this morning on NPR (I can’t find the link on the site?). It had to do with village officials paying fisherman… to maintain the mangrove swamps since the swamps were shown to greatly decrease the impact of tidal waves (and large storms) on land. Previously government officials had supported (and I would imagine many still do…) large developers raising the mangrove swamps and building big beachfront hotels.

Mind controls body in extreme experiments

Mind controls body in extreme experiments by William J. Cromie, Harvard University Gazette:

During visits to remote monasteries in the 1980s, Benson and his team studied monks living in the Himalayan Mountains who could, by g Tum-mo meditation, raise the temperatures of their fingers and toes by as much as 17 degrees. It has yet to be determined how the monks are able to generate such heat.

The researchers also made measurements on practitioners of other forms of advanced meditation in Sikkim, India. They were astonished to find that these monks could lower their metabolism by 64 percent. “It was an astounding, breathtaking [no pun intended] result,” Benson exclaims.

To put that decrease in perspective, metabolism, or oxygen consumption, drops only 10-15 percent in sleep and about 17 percent during simple meditation.

In my opinion, much more evidence is needed to take these claims seriously but still it is interesting.

Sea Slug Photo Gallery

Nudibranchia Gallery:

Nudibranchs belong to sea slugs. As all other gastropods, they are slow moving bottom dwellers. They have soft bodies and most of them lack an external protective shell. Their secondary gills are exposed outside, as reflected by their neo-latin/greek name “nudibranch” meaning “nude/naked gills”… To protect themselves from predators many developed toxic or bad tasting glands in the skin, and their bright colors warn predators of their horrible taste.

Big Big Lions

Lions Hunting in the Water

Relentless Enemies program to air on National Geographic in January.

The superlions marooned on an island by Zoe Brennan discusses the program:

“We discovered this tiny sandy island in the Okavango,” says Dereck. “It is extraordinary because it became totally isolated from the mainland 15 years ago when the course of the river changed, and a huge herd of buffalo and lions were trapped on a piece of land measuring 200 square kilometres.”

Through this twist of geographical fate, these two ancient species are now engaged in a desperate battle of survival — watched by six bemused refugee wildebeest and a handful of similarly outnumbered warthogs.

Thus, the island has become a unique, ecological experiment. In order to exist without the customary spectrum of weaker African prey like zebra, giraffe and impala, the Duba lions have had to develop distinct strategies in order to trap the single available food source.

Scientists Building a Safer Mosquito

Scientists building a better mosquito by Catherine Clabby:

Eliminating the pests appears impossible. But scientists are attempting to re-engineer them so they cannot carry disease. If they manage that, they must create enough mutants to mate with wild insects and one day to outnumber them.

Researchers chasing this dream, including an N.C. State University entomologist, know they may court controversy. Genetically modified crop plants such as soybeans, corn and cotton have become common in the United States, but an altered organism on wings would be a first.
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Gould is working on the project with scientists on four continents. They landed $19.7 million under a Grand Challenges in Global Health grant offered by the Gates philanthropy and a National Institutes of Health foundation. The funders selected researchers ready to collaborate rather than compete on risky research aimed at solving massive health threats in poor places.

The genetic tinkering is focused at first on dengue, a tropical virus re-emerging in Asia, Latin America and Africa. While dengue claims a fraction of the million or more victims that malaria kills annually, it strikes 50 to 100 million people each year with severe flu symptoms. Outbreaks disrupt families and communities and overburden health systems.

Ageless Turtles

All but Ageless, Turtles Face Their Biggest Threat: Humans by Natalie Angier:

Dr. Christopher J. Raxworthy, the associate curator of herpetology at the American Museum of Natural History, says the liver, lungs and kidneys of a centenarian turtle are virtually indistinguishable from those of its teenage counterpart, a Ponce de Leonic quality that has inspired investigators to begin examining the turtle genome for novel longevity genes.

“Turtles don’t really die of old age,” Dr. Raxworthy said. In fact, if turtles didn’t get eaten, crushed by an automobile or fall prey to a disease, he said, they might just live indefinitely.

Turtles have the power to almost stop the ticking of their personal clock. “Their heart isn’t necessarily stimulated by nerves, and it doesn’t need to beat constantly,” said Dr. George Zug, curator of herpetology at the Smithsonian Institution. “They can turn it on and off essentially at will.”

Micro-robots to ‘swim’ Through Veins

image of Escherichia coli bacterium with flagella

Micro-robots take off
Photo: Transmission Electron Microscopy photograph of an Escherichia coli bacterium with flagella. The micro-robots are being developed to mimic the swimming behaviour of E.coli.

Micro-robots that can ‘swim’ through the vascular and digestive systems of the human body to perform medical tasks via remote control and, in many cases, avoid invasive major surgery, are being developed at Monash University following today’s announcement that the project has been funded through the Australian Research Council’s Discovery Projects scheme.

How Does the Immune System Remember

Scientists find key to immune system’s ability to remember

The protein, which scientists call Lck, is essential for immune system T cells – white blood cells that attack virus-infected cells, foreign cells and cancer cells… Lck is important in helping “naive” T cells – those cells that have never been exposed to a particular pathogen – capture the receptor template of the invading agent and store it for future reference… Following infection or vaccination, Lck initiates a biochemical chain of events that vastly increases the number of T cells that march off to combat the invader.

After the infection subsides, the number of T cells marshaled to fight that agent decreases dramatically. But a smaller subset, known as “memory” cells, retains the imprint of its previous encounter should the pathogen make a return appearance. According to the study, while Lck primes naive cells to fight a pathogen, it is not required by memory cells, which initiate the fast and furious response when that same pathogen comes calling again years later. Unlike naive T cells, which are confined to the lymphatic system, memory T cells are found everywhere in the body, enabling them to sense and react more quickly when an infectious agent is reencountered.