Category Archives: Life Science

Science Summary: Photosynthesis

Seed’s latest cribsheet, a one page summary of Photosynthesis:

Through the process of photosynthesis, plants, algae, and bacteria use sunlight to convert water and carbon dioxide into the oxygen and food that sustain much of life on Earth. This Cribsheet covers the basics of photosynthesis: where it happens, how light is used in the process, and why we think photosynthesis may have triggered the rise of complex life. In addition, we tell you why plants are green and how photosynthesis could temper climate change—if rainforests and oceanic ecosystems aren’t destroyed.

One Species’ Genome Discovered Inside Another’s

Video describing genome inside genome Watch video of Professor Werren describing the genome-in-a-genome at the University of Rochester.

More incredible gene research. Scientists at the University of Rochester and the J. Craig Venter Institute have discovered a copy of the genome of a bacterial parasite residing inside the genome of its host species. The research, reported in today’s Science, also shows that lateral gene transfer—the movement of genes between unrelated species—may happen much more frequently between bacteria and multicellular organisms than scientists previously believed, posing dramatic implications for evolution.

Such large-scale heritable gene transfers may allow species to acquire new genes and functions extremely quickly, says Jack Werren, a principle investigator of the study. If such genes provide new abilities in species that cause or transmit disease, they could provide new targets for fighting these diseases.

The results also have serious repercussions for genome-sequencing projects. Bacterial DNA is routinely discarded when scientists are assembling invertebrate genomes, yet these genes may very well be part of the organism’s genome, and might even be responsible for functioning traits.

“This study establishes the widespread occurrence and high frequency of a process that we would have dismissed as science fiction until just a few years ago,” says W. Ford Doolittle, Canada Research Chair in Comparative Microbial Genomics at Dalhousie University, who is not connected to the study. “This is stunning evidence for increased frequency of gene transfer.”

Continue reading →

Ocean Foam

Cappuccino Coast: The day the Pacific was whipped up into an ocean of froth

One minute a group of teenage surfers were waiting to catch a wave, the next they were swallowed up in a giant bubble bath. The foam was so light that they could puff it out of their hands and watch it float away. It stretched for 30 miles out into the Pacific in a phenomenon not seen at the beach for more than three decades.

Scientists explain that the foam is created by impurities in the ocean, such as salts, chemicals, dead plants, decomposed fish and excretions from seaweed. All are churned up together by powerful currents which cause the water to form bubbles. These bubbles stick to each other as they are carried below the surface by the current towards the shore.

As a wave starts to form on the surface, the motion of the water causes the bubbles to swirl upwards and, massed together, they become foam.
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As for 12-year-old beachgoer Tom Woods, who has been surfing since he was two, riding a wave was out of the question. “Me and my mates just spent the afternoon leaping about in that stuff,” he said. “It was quite cool to touch and it was really weird. It was like clouds of air – you could hardly feel it.”

Sexy Math

Mean Girls:

British researchers, stated that men had 12.7 heterosexual partners in their lifetimes and women had 6.5.” These numbers, though Kolata doesn’t say so, are means, not medians. In this case, it’s indeed mathematically impossible that the numbers are correct. The medians in the British sample? Seven and four, same as in the American study—so you can stop worrying about a transatlantic promiscuity gap.

“It is logically impossible for heterosexual men to have more partners on average than heterosexual women,” she explains. “Those survey results cannot be correct.” Kolata even quotes a theorem to this effect, backed up by mathematician David Gale of Berkeley: The average number of partners has to be the same for men and women.

This article makes several good mathematical and scientific points, including the dangers of trusting reports by participants. Also I can see if this page is more popular than some of the other math posts. For awhile now I have noticed “sex 100” showing up as one of the terms guiding the most visitors to this site. I wondered what that could be – I just took a look: Bdelloid Rotifers Abandoned Sex 100 Million Years Ago. I think maybe those searchers didn’t exactly find what they wanted.

Regular Aerobic Exercise for a Faster Brain

Lobes of Steel

Scientists have suspected for decades that exercise, particularly regular aerobic exercise, can affect the brain. But they could only speculate as to how. Now an expanding body of research shows that exercise can improve the performance of the brain by boosting memory and cognitive processing speed. Exercise can, in fact, create a stronger, faster brain.
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But something else happened as a result of all those workouts: blood flowed at a much higher volume to a part of the brain responsible for neurogenesis. Functional M.R.I.’s showed that a portion of each person’s hippocampus received almost twice the blood volume as it did before. Scientists suspect that the blood pumping into that part of the brain was helping to produce fresh neurons.

The hippocampus plays a large role in how mammals create and process memories; it also plays a role in cognition. If your hippocampus is damaged, you most likely have trouble learning facts and forming new memories. Age plays a factor, too. As you get older, your brain gets smaller, and one of the areas most prone to this shrinkage is the hippocampus. (This can start depressingly early, in your 30’s.) Many neurologists believe that the loss of neurons in the hippocampus may be a primary cause of the cognitive decay associated with aging.

Common Virus May Contribute to Obesity

Common virus may contribute to obesity

Infection with human adenovirus-36 (Ad-36) seems to direct adult stem cells from fat tissue to turn into fat cells, researchers have found in lab experiments. Stem cells not exposed to the virus, in contrast, were unchanged. More importantly, the researchers have identified the specific gene in the virus that appears to be involved in this obesity-promoting effect: E4Orfl.

The field of research investigating the role of viruses in obesity — dubbed “infectobesity” — is still relatively new and experimental. Researchers don’t believe that infection with one of these pathogens is the sole cause of obesity but they say some obesity cases may involve viral infections.

‘Looming Crisis’ from NIH Budget

‘Looming crisis’ from NIH budget by Ted Agres:

“Promising research is now being slowed or halted,” said Edward Miller, dean of Johns Hopkins Medicine. “We are seeing veteran scientists spending time not in labs but on the fundraising circuit. We are seeing young researchers quitting academic research in frustration, having concluded that their chances of having innovative research funded by NIH are slim to none,” Miller told a Capitol Hill news conference yesterday.

The scientists released a report prepared by 20 leading researchers from a consortium of nine academic institutions and universities, that outlines the benefits of increased NIH funding on biomedical innovations, and warns of the negative implications should the present budget be left unaddressed. The report cited threats from unexpected new diseases, such as SARS and pandemic influenza, as well as obesity, HIV, and bioterrorism.

While Congress and the White House doubled NIH’s budget from 1998 to 2003, funding has failed to keep pace with inflation. NIH’s budget has hovered at around $28 billion, but once inflation is factored in, its purchasing power has fallen 13% over the past four years. According to the report, an average of eight out of ten NIH grant applications currently go unfunded, while at the National Cancer Institute, only 11 percent of grants are funded. “This is a recipe for disaster,” Miller said. “The number of termination letters at Johns Hopkins is up three-fold.”

Peak Soil

An interesting article. Obvious the author has a biased viewpoint (that doesn’t mean the conclusions are wrong but it certainly can make one cautious – just as if a drug company shows results that their drug is effective or safe – you just have to pay a bit more attention…). I would be interested in others thoughts on this. My perception (though it is just an opinion based on limited facts) is that topsoil loss is a problem and that using corn for ethanol is more a federal government payoff to buy votes than a wise national policy. I am less inclined to accept some of the more extreme suggestions in the article. Peak Soil: Why cellulosic ethanol, biofuels are unsustainable and a threat to America

“The nation that destroys its soil destroys itself.” – President Franklin D. Roosevelt
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When you take out more nutrients and organic matter from the soil than you put back in, you are “mining” the topsoil. The organic matter is especially important, since that’s what prevents erosion, improves soil structure, health, water retention, and gives the next crop its nutrition. Modern agriculture only addresses the nutritional component by adding fossil-fuel based fertilizers, and because the soil is unhealthy from a lack of organic matter, copes with insects and disease with oil-based pesticides.

I believe it makes sense to research things like bio-fuels. However I am not convinced massive payments to the political well connected is a wise course of action.

Raised Without Antibiotics

Tyson is going to start selling chicken Raised Without Antibiotics. The overuse of antibiotics is a huge problem and the overuse in the raising of livestock is a huge problem.

“While we have great confidence in the quality of our traditional chicken, we’re also committed to providing mainstream consumers with the kind of products they want,” said Richard L. Bond, president and CEO of Tyson Foods. “According to our research, 91% of consumers agree it’s important to have fresh chicken produced and labeled ‘raised without antibiotics’,” Bond said.

Tyson started selling 100% All Naturalâ„¢, Raised Without Antibiotics chicken this week. The product is being distributed nationwide in newly-designed packaging highlighting that the chicken is raised without antibiotics and contains no artificial ingredients.

While it is nice they will start selling a portion of chicken raised without using antibiotics and endangering the health of the community by helping evolve super-resistant bugs this is really a pretty small step I would guess. The risk is not even mainly to the person eating the food pumped full of antibiotics it is to everyone when drug resistant bacteria are evolved through the overuse of antibiotics. Also, 100% All Natural is trademarked? Give me a break.

Nationwide Survey Reveals Most Americans are Unaware They Consume Beef and Poultry Raised on Antibiotics (2003)

“Antibiotic medicines are losing effectiveness on humans due to their increased use in animal feed,” said Margaret Mellon, Ph.D, JD, director of the food and environment program for the Union of Concerned Scientists. “Animals raised in natural environments rarely require the use of antibiotics. Americans who choose meat produced this way are making conscious decisions to ensure that antibiotics will still be working when they or their family need them.” The Union of Concerned Scientists estimates that 70 percent of all antibiotics in the United States are now fed to animals raised for human consumption in order to hasten the animals’ growth or prevent illness amid crowded, unsanitary conditions on factory farms.

Abuse of Antibiotics at Factory Farms Threatens the Effectiveness of Drugs Used to Treat Disease in Humans:

According to the Center for Disease Control, more than one-third of the salmonella poisoning cases in 1997 were found to be resistant to five antibiotics. Drug resistance in campylobacter bacteria, the most commonly known cause of bacterial food-borne illness in the United States, increased from zero in 1991 to 14 percent in 1998.
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The European Union, on the recommendation of the World Health Organization, has banned the use of antibiotics to promote the growth of livestock animals when those drugs are also used to treat people. The Center for Disease Control has agreed with this position, but the U.S. government has failed to reduce the threat that ineffective antibiotics pose to human health. (Lieberman, et.al., 1999)

To reduce serious health threats, the Food and Drug Administration should ban the use of antibiotics to promote livestock growth when those antibiotics are used to treat humans.

Galactic Dust with the Ability to Reproduce?

Dust ‘comes alive’ in space:

An international panel from the Russian Academy of Sciences, the Max Planck institute in Germany and the University of Sydney found that galactic dust could form spontaneously into helixes and double helixes and that the inorganic creations had memory and the power to reproduce themselves.

The new research, to be published this week in the New Journal of Physics, found nonorganic dust, when held in the form of plasma in zero gravity, formed the helical structures found in DNA. The particles are held together by electromagnetic forces that the scientists say could contain a code comparable to the genetic information held in organic matter. It appeared that this code could be transferred to the next generation.

Professor Greg Morfill, of the Max Planck institute of extra-terrestrial physics, said: “Going by our current narrow definitions of what life is, it qualifies. “The question now is to see if it can evolve to become intelligent. It’s a little bit like science fiction at the moment. The potential level of complexity we are looking at is of an amoeba or a plant.”

“I do not believe that the systems we are talking about are life as we know it. We need to define the criteria for what we think of as life much more clearly.”

Interesting, though I don’t really understand what they mean by memory and reproduction in this context.

Related: Cosmic ‘DNA’: Double Helix Spotted in Space – “Magnetic forces at the center of the galaxy have twisted a nebula into the shape of DNA, a new study reveals. The double helix shape is commonly seen inside living organisms, but this is the first time it has been observed in the cosmos.”