With all the rain this week many of you may be wondering
"will I get less wet if I run or walk?"
Well thank god for Minute Physics, they let us know which is better, and exactly why.

We’ve been tinkering with the DNA of other species for thousands of years. We just didn’t know what we were doing.

Starting about ten thousand years ago, humans began to steer the evolution of animals and plants. Our ancestors collected certain seeds instead of others, started to plant them in gardens, and gradually produced domesticated crops. They didn’t know which genetic variants they were choosing, or how those genes helped build new kinds of plants. All they knew was that some plants were better than others. Over thousands of years, for example, an innocuous bush called teosinte turned into tall stalks with gargantuan seeds–otherwise known as corn.

Our ancestors could see the outward changes they were bringing to crops like corn, as well as livestock like cows and pigs. But hidden from view, other species were evolving in response to the dawn of agriculture. Early dairy farmers had no idea that they needed certain bacteria to turn their milk to yogurt or cheese. And they didn’t realize that the bacteria were adapting to this strange new environment that had never existed before.

And it wasn’t just the bacteria in pots of yogurt that were evolving. So were the microbes in our mouths.

The human mouth is home to hundreds of species of bacteria. While some of them keep our mouths healthy, others can cause us trouble. One of the worst offenders is Streptococcus mutans. It lives in the nooks of our teeth, feeding on carbohydrates. It excretes lactic acid as waste, and the acid eats away at the enamel on which it rests. Over time, Streptococcus mutans can dig a hole in a tooth–otherwise known as a cavity.

Streptococcus mutants is not some jack-of-all trades microbe that happens to drop onto our teeth once in a while. For them, human teeth are the world. They are passed down from mothers to their children, and colonize those children for life. Other mammals have closely related Streptococcus strains on their teeth as well, suggesting that these bacteria have been tracking their hosts–and dwelling on their teeth–for tens of millions of years.

Recently Michael Stanhope, a biologist at Cornell, and his colleagues carried out a large-scale study of Streptococcus mutans. They looked at 57 colonies that had been gathered from the mouths of people in Brazil, Britain, Iceland, Hong Kong, South Africa, Turkey, and the United States. The scientists tallied up the genes that the bacteria had in common, as well as the ones that were only present in some people. (Bacteria sometimes pick up genes from other species.) Then the scientists compared all the human strains of the bacteria to Streptococcus living in rats, hamsters, and monkeys to pinpoint the DNA that is unique to our own passengers. And when they analyzed all these genes, they discovered something remarkable: these bacteria appear to have evolved with resounding success in response to the rise of civilization.

The Streptococcus mutans the scientists found in people’s mouths shared 1490 genes in common–a core genome, as it’s known. These shared genes varied from mouth to mouth, Stanhope found, with minor mutations sprinkled among them. It’s possible to tally up these mutations and use them to reconstruct some of the history of their ancestors. Stanhope and his colleagues found that Streptococcus mutans underwent a population explosion. And that explosion started ten thousand years ago.

It may well be no coincidence that this was also when our ancestors began to farm. Those early farmers shifted to diets dominated by corn and other grains–which turned the human mouth into an endless banquet of carbohydrates.

Stanhope and his colleagues were also able to pinpoint some of the genes that were important for Streptococcus mutans’s adaptation to civilization. Fourteen genes, for example, show signs of having experienced strong natural selection. Some of those evolved genes are essential for breaking down sugar. Others help the bacteria survive in the acidic conditions that arise in the mouth when we eat starches.

Perhaps most intriguing of all the genes in Streptococcus mutans are the 148 that Stanhope and his colleagues found in every human strain, but in none of the related bacteria in the mouths of other animals. The best explanation for this is that Streptococcus mutans picked these 148 genes up from other species in our bodies. Once Streptococcus mutans grabbed these genes, it didn’t let them go.

The function of the genes hints at their value. Some provide additional help at breaking down sugar. Others create more defenses against low pH. Others produce toxins that can kill off other species of bacteria that are competing with Streptococcus mutans for the spoils of civilization.

These adaptations have made Streptococcus mutans spectacularly successful, and they’ve also provided us with a lot of misery. The cavities would be bad enough. Archaeological evidence indicates that cavities went from rare to common with the advent of agriculture. Making matters, worse, however, is the fact that when Streptococcus mutans gets into the bloodstream through the gums, it can make its way to the heart and cause problems there, too.

Appreciating how Streptococcus mutans evolved into such a successful burden might offer a way to fight it. Stanhope’s study provides a veritable catalog of adaptations that the germ relies on to transform the agricultural revolution into trillions of new bacteria. It might be possible to target one of those adaptations and attack Streptococcus mutans with pinpoint accuracy, leaving the rest of the residents of our mouths unharmed. We may have unwittingly made Streptococcus mutans what it is today, but we can wittingly do something about it now.

Covering yourself in hagfish slime may not sound like the smartest thing to do… But researchers from Canada’s University of Guelph have discovered that it’s actually not such a bad idea.

The hagfish (which isn’t really a fish in the conventional sense) is a living fossil. It has undergone little to no evolution in the past 300 million years. It has an interesting and effective defence mechanism that can repel even sharks. When threatened, it releases large quantities of protein. This protein, when released into the water, forms threads that turn the immediate environment of the hagfish thick and gooey. The slime, which “smells like dirty sea water”, according to one of the researchers, deters predators from attacking the hagfish.

The researchers have found that the protein threads can be isolated from the slime (via the removal of water and mucous). The protein threads themselves are categorized as ‘intermediate filaments’. Each thread is 100 times smaller than a single human hair. These fine threads can be woven to create fabric that’s as strong as nylon or plastic. With more research, these fabrics can even be used to make clothes! Hagfish produce large amounts of slime in mere seconds. The mere efficiency of this process grants it an advantage over harvesting silk from silkworms. Furthermore, the material is much more sustainable than artificial fibers like nylon and polyester. In the words of the head researcher, Atsuko Negishi, “This work is just the beginning of our efforts to apply what we have learned from animals like hagfishes to the challenge of making high-performance materials from sustainable protein feedstocks.”

The next challenge would be to make the process feasible on an industrial scale. It’s unlikely that slime will be directly harvested from the hagfish in large amounts. Alternatively, the slime-making genes might be transplanted into bacteria, which can be cultured to provide the slime on a much larger and more feasible scale.

more

the video is in english and then dubbed over in another language, but even without commentary it is amazing to see what happens to blood when exposed to snake venom

The Horseshoe crab has played a vital role in the pharmaceutical industry, the video below shows some of the amazing things we have learned from them.

Everyone has heard of blood groups such as A-, AB, B+ etc. But how many of us actually understand what they mean and the complicated differences between each group?

Blood is made up of four major components: 

interesting explanation of how particles move 

one of the most epic battles ever caught on film. 
shows the daily struggle of some of the amazing animals in the world. 

gets good at 3:00