Posts Tagged ‘biology’

Meet the weird bird that’s half-chicken, half-turkey [Biology]

16 Mar
This is the Transylvanian naked neck chicken, popularly known as the "churkey" because it appears to have the body of a chicken and the head of a turkey. And this mysterious mutation could actually help feed the world. More »

How did humans really evolve? [Io9 Backgrounder]

04 Mar
Almost two million years ago, a band of brave explorers left their families behind in their warm, tropical home and sought refuge in northern lands. Armed with sharp stone tools and their wits, they followed the coast as far north as they could, then began to veer east, settling on the sunny, fertile shores of an inland sea that today we call the Mediterranean. Their children spread further north and east, and a million years later they had established settlements along the coasts of today's Europe, England, and China. More »

A drug that can make your old memories like new [Mad Science]

04 Mar
There are drugs that help you remember what you learn, and ones that erase your memory. But until now, there have no substances with the power to enhance and strengthen old memories hovering on the brink of being forgotten. Now a group of neuroscientsts say they've isolated a single enzyme in the brain that can help long-term memories remain crisp in your mind. More »

The truth about why things smell bad: Vibrating molecules [Biology]

15 Feb
For over a century, our sense of smell has been explained with the "lock and key" hypothesis, which holds that each odor molecule has a particular shape that allows it to fit into particular smell receptors in the nose. But now a controversial study involving fruit flies suggests that hypothesis might miss the truth entirely - the secret, they say, is all in the vibrations. More »

Solar-powered hornet is the Superman of the animal kingdom [Mad Biology]

13 Feb
Plants use photosynthesis to turn sunlight into energy every single day. This ability appeared to be completely unknown in the animal kingdom, leaving the living solar battery that is Superman as the only animal to ever harness the sun's rays for power. But now we've discovered that a type of hornet is doing its own homegrown photosynthesis, absorbing sunlight and turning it into useful energy. It's the first animal we've ever discovered that possesses this ability...and we might be able to harness our own version of it for alternative energy. More »

Women’s tears might actually reduce men’s testosterone [Mad Science]

06 Jan
The fact that we cry when we're feeling sad, overjoyed, or otherwise emotional is thought to be a uniquely human trait. But biologists long suspected tears have some other function, and now we might know: they reduce men's sexual arousal. More »

You are what your parents eat [Obesity]

23 Dec
Proving once again that life is utterly unfair, it appears that your parents' diet can leave a permanent mark on your genetics. More »

"Brown fat" injections could solve the obesity problem [Medical Breakthroughs]

20 Dec
Most fat cells are called white fat cells - they store excess energy and make it tough to lose weight. But we've discovered how to turn mice's white fat cells into energy burning brown fat cells, and humans could be next. More »

Giant storks lived among the ancient "hobbit" people of Indonesia [Monsters Among Us]

08 Dec
The ancient species of "hobbit people" called Homo florensiensis may have shared their Indonesian island with giant 6-foot-tall cranes. Their antagonistic relationships with these bird monsters may have made it into ancient art, too. More »

Bacteria evolve a way to share electrons

04 Dec

Life is powered by the shuffling of electrons. When organisms break down a food source like a sugar, they're really extracting high-energy electrons, which they shuffle down through intermediate proteins before they end up in a final electron acceptor. For most of the life we're familiar with, that acceptor is oxygen. But for various microbes that thrive in the absence of oxygen, a variety of other chemicals are used.

A few bacteria don't even use a chemical receptor at all, instead transferring their excess electrons to metals in their environment (these can form the basis of microbial fuel cells). Now, researchers have witnessed the evolution of a bacteria that transfers its electrons to another bacteria, which goes on to put them to further use.

There are a number of symbiotic relationships like this among the microbes, some of which can metabolize an organic molecule, while others can transfer them to a low-energy chemical. Typically, the bugs exchange an organic chemical or hydrogen to a symbiotic bacteria that extracts further energy from it.

In the current paper, the authors forced two different species of bacteria to live in an anaerobic environment, and provided them with ethanol as food. Initially, they grew very poorly. After several transfers, however, the rate of growth improved, and small, colored nodules began to appear in the culture, which contained a mix of the two types of bacteria. The authors checked a number of the chemicals that are typically used to transfer electrons in these symbiotic cultures, but saw no evidence of their being used.

To figure out what was going on, they did whole-genome sequencing, and found only one change: a single base missing in the gene for a protein that regulates RNA production. Making a similar mutation in another strain also allowed those bacteria to form quick-growing nodules. The mutation appears to cause proteins involved in electron transfer to be expressed at increased levels. These proteins end up on pilli, arm-like structures that extend out from the bacteria.

As a result, the authors conclude that one of the two species of bacteria has evolved the ability to transfer electrons directly to their neighboring species, allowing both to get more energy out of the limited food available.

Science, 2010. DOI: 10.1126/science.1196526  (About DOIs).

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