Problem drinkers: what's it like to be a vampire?

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2017-10-31 11:00:12

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Problem drinkers: what's it like to be a vampire?

Jennifer Zaspel can't explain why you decided to poke your thumb into the vial mol. I just want to. It catches moths in the July night in the far East in Russia and caught calyptra (Calyptra), with brown curls on the wings, resembling a dried leaf in plastic bottle Assembly. Of the 17 tropical species calyptra eight were vampires. The males are sometimes moving away from its fruit diet, sinking its robust oral jaws in mammals such as cattle, tapirs and even elephants and people to drink fresh blood.

But Zaspel believed that is outside the territory where you could encounter types of vampires. She caught C. thalictri, widely known in Switzerland, France and Japan as strict pledgor.

Before you wrap the bottle with a moth, "I'm just so stuck in his thumb, to see what it will do," says Zaspel. "She pierced my thumb and I start to eat."

Here you have eight vampires. Have zaspel, entomologist of the public Museum of Milwaukee, still puzzled by the genetics of moths in the two Russian places that she visited in 2006. Males will bite the researcher's finger, if they offer, but genetic studies show that these moths are included in the list of friendly species. At least should be.

The Proboscis of Calyptra thalictri extracts the blood from the scientist. For a long time it was believed that this moth feed exclusively on fruit, because its proboscis is better adapted to pierce a plum than a thumb.

"I would compare it to a bee bite", says Zaspel. In the pursuit of science, one of my colleagues has Zaspel voluntarily documented the experience, noting that a moth ate the whole 20 minutes. These bites definitely do not go unnoticed. These moths and other vampires risk their life while you eat.

To be Interrupted by periodic red Breakfast or try to survive alone blood much more difficult than in the movies. Relatively few animals are this way of life: some insects and other arthropods, some mollusks, some fish, sometimes birds and, of course, three kinds of bats.

Blood is not the simple food. The animal typically tries to absorb as much food at a time. But such heroic amounts of blood can be toxic. One bloody food is not enough because it lacks of some basic nutrients. When this way of life of the colon have a special physiology. The modern tools of genetics and molecular biology reveal a hidden specialization needed to supply blood, along with the cruel practices, which sometimes go to extremes, like transfer of blood from moth to moth. While many of these biological adaptations could never compare with the power of the immortal vampire, in a sense they can be considered superpowers.

the

the Big dish

To understand the risks that are real vampires, imagine an animal whose weight more your 35 million times. Now try to bite. Hard enough to bleed.

Obviously, it's going to be pissed. "You could easily kill a carrier," says molecular physiologist insect Pedro Oliveira from the Federal University of Rio de Janeiro. The multiplier 35 million is applied for a 2 milligram mosquito attacking a 70-kg person.

To Find such a huge source of blood is not easy. "If you go into the woods between vertebrate hosts hundreds of meters distance, and hundreds of meters to kilometers for us," says Oliveira. Then the little vampire need to find a capillary, which can penetrate just a few millimeters below the skin's surface. In the case of a man fit only about 10% of the skin.

The Professional part of the sucking of blood, the bug Rhodnius prolixus, has enzymes in the intestine that hold the tyrosine in the diet from crystallization and perforation of fabrics.

Considering the dangers and difficulties faced by blood donors, "most of them try to minimize the number of visits", says Oliveira. They drink quickly and drink a lot. The young insect, bloodsucker, capable of spreading debilitating Chagas disease, in just a few minutes drinking the blood in 10 times its weight.

To tie it to human physiology? Forget. There are people who deliberately drink the blood, and that's another story, but even small amounts by the standards of vampires, for example, blood, swallowed in the result of nasal bleeding, can cause an upset stomach, ie diarrhea, says Tomas Ganz of the school of medicine David Geffen University of California Los Angeles. Fresh blood is hard to digest by the human gut, and very little water from the blood is extracted and sent to the kidneys. Ganz compares the blood and fluids that people drink to clean the digestive system, quick and nasty, for a colonoscopy.

For large receptions blood in food ingredients that were harmless in large amounts, can be toxic. "Dose determines the poison," said Oliveira.

Remove from the blood the water and get 90% composed of protein substance. Oliveira faced with the danger of this protein, when investigated the genetics of one of the American bugs Rhodnius prolixus in the laboratory. This teardrop-shaped beetle, with the body tapering to the head, hiding in the crevices indoors or outside. At night, the males and females of a beetle looking for people, their Pets or other mammals, to bloody dinner. This beetle is extremely secretive and, unlike vampires, butterflies, poisons its prey during a bite. Unlike mosquitoes, whose bites transmit pathogens through the saliva, this beetle transmits the parasites of Chagas disease through feces, which are left on the media.

Of all amino acids found in this great product, only tyrosine has a large array of enzymes ready to break it in the stomach of the beetle, shown by scientists in 2014. Search enzyme degrading tyrosine in the intestine, is "a little weird", says Oliveira. In mammals, the liver and kidneys are the only organs with the enzymes that Deplete tyrosine. Again, most mammals do not flood the gut with only one protein.

When the researchers turned off the ability to the destruction of the tyrosine at the beetle, either genetically or chemically blocking the enzymes, the beetles died after lunch. About Oliveira and colleagues wrote in Current Biology in 2016. Part of the dead beetles revealed that tyrosine crystals perforating the bowel and its contents spilled into the cavity of the body. This discovery, noted scientists, I can give molecular biologists own medicine, which will be used to kill vampires.

Blood sucking arthropods have evolved independently several times (up to 21), but most vampires had to solve the same problem with the various quirks of biochemistry. However, the problem of detoxification of tyrosine may be an issue that many genealogical solved very similar way, according to Oliveira.

The First strikes on weapons that disable General chemistry — a compound inhibiting the enzyme HPPD. The enzyme stops the degradation of tyrosine, and not only the above-mentioned bugs. When testing method was safe for dairy beetles and mealy worms.

the

Bad blood

Tyrosine is just one of the nutrients that become toxic due to the volume. In the real world the ability of vampires to excrete the wastes is much more important than some fictional power to raise the truck.

A Nephrologist Jonas Axelsson of the Karolinska Institute in Stockholm and his colleagues studied renal function in bats-vampires in comparison with their mass species living fruit or nectar. The human diet usually consists of 50 to 120 grams of protein a day, but if to eat like bat-vampire, human equivalent would have amounted to 6000 grams of protein per day for a 70-kilogram body. Such an overdose of protein means that these bats have a protein concentration protein and metabolic waste products such as urea, that will instantly lead to kidney failure in humans.

But the mouse-vampires in the order. Their kidneys the same size as the kidneys other bats. Mouse-vampires devote more space long tubules that are engaged in the reabsorption of nutrients from freshly prepared urine, he said.

Most of the protein in blood is hemoglobin, an iron containing a miracle molecule that carries oxygen through the body and helps vertebrates grow big and fat. However, the rapid digestion of such amounts of hemoglobin can release potentially toxic dose of iron in the bloodstream. A healthy person can bring happiness to your doctor concentration of iron in the blood of about 127 micrograms per 100 milliliters. However, concentrations 200 times higher, apparently, do not harm mnogoobraznye fish in their larval form. Larvae take iron in the process of eating whatever I find. When the sea lamprey (Petromyzon marinus) are ripe, they have a ruthless series of teeth with which they pierce and suck blood from other fish. The concentration of iron in the blood fall to about 10 times the healthy level for a man content.

But even worse blood-sucking sea lamprey selection, which do not allow the victim's blood clotting

First, the lamprey adheres to the skin, which resembles "wetted suction Cup on the face," says an expert on lampreys, a biologist Margaret Docker of the University of Manitoba in Winnipeg, Canada. In the experiment she let a blood-sucking silver lamprey (Ichthyomyzon unicuspis) to bite her cheek. They are found in lakes and streams of North America. Only half of the world's 38 species of lampreys suck blood.

Lampreys are well captured victim. Some are not disengaged even when driving up waterfalls or dams. Very rarely it happens that fish...

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