A man in China who, after eating high-carbohydrate or sugary meals, became so intoxicated that he blacked out, has led researchers to discover strains of bacteria in the human gut that could be an important driver of the world’s most common liver disease.#Science #Biology #Bacteria #Microbiomes
Doctors previously had diagnosed the man’s intoxication problem as autobrewery syndrome, a rarely reported condition in which people become drunk from starchy or sugary foods. It is thought to be caused by gut fermentation, aided by an abundance of yeast. But antifungal treatment had no effect on the man. Liver biopsies showed he had nonalcoholic steatohepatitis (NASH), the severe form of NAFLD. He was moved to the intensive care unit and closely observed. Doctors noted that after he ate a meal high in sugar, his blood alcohol level rose to as high as 400 milligrams per deciliter. “That’s equivalent to 15 shots of 40% [80-proof] whisky,” Yuan says.
Because some other microbes can metabolize sugars into alcohol, Yuan and colleagues analyzed 14 of the man’s stool samples taken at different times for species-specific bacterial DNA fragments. They found that when he was most intoxicated, 18.8% of the bacteria in a sample were K. pneumoniae, a 900-fold increase over normal. When they put these bacteria in a medium of yeast and sugar, they could isolate strains of the bacterium that produced high, medium, or low levels of alcohol.
Yuan and colleagues report that the initial patient they studied recovered from his bacteria-driven autobrewery syndrome after he began to take antibiotics and changed his diet. His NASH has abated, too. Her team is now planning to study the gut microbes of a large group of people, including children, over time. “We want to investigate why some people have high-alcohol-producing strains of K. pneumoniae in their gut while others don’t,” she says.
Diehl cautions that the new study speaks only to a subset of NAFLD patients. But she predicts “this will work will attract a lot of attention.”
[F]our of the lab’s scientists dedicated themselves to testing a relatively new claim about pangolin scales—that they contain tramadol, an opiate used for pain relief that, like all opiates, has the potential for abuse.#Biology #Nature #Mammals #Pangolins
Wildlife forensic scientist Rachel Jacobs and her colleagues examined the chemical signatures of clippings of scales from more than 100 pangolins and found no traces of tramadol. They published the findings in June in the journal Conservation Science and Practice.
“There’s so much misinformation surrounding this whole thing,” Jacobs says.
Pangolin scales are made of nothing more than keratin, a protein that makes up fingernails, hair, horns, claws, and hooves. It has no scientifically proven medicinal value. Jacobs was doing related research when she first heard the rumors about pangolin scales being smuggled into the U.S. for tramadol. “It surprised us. We thought it was a bit bizarre,” she says. “We hadn’t heard of it before.”
In the late 1980s, an Inuit subsistence hunter named Jens Larsen killed a trio of very strange whales off the western coast of Greenland.#Science #Biology #Nature #Whales #Narwhal #Beluga #Hybrids
In 1990, it caught the attention of Mads Peter Heide-Jørgensen, a scientist who studies marine mammals. With Larsen’s permission, he took it to the Greenland Fisheries Research Institute in Copenhagen for study. And after comparing it to the skulls of known belugas and narwhals, he suggested that it might have been a hybrid between the two species—a narluga.
By analyzing DNA extracted from one of the creature’s teeth, a team led by Eline Lorenzen from the Natural History Museum of Denmark showed that it was a male, born to a beluga father and a narwhal mother. Most of its DNA was a half-and-half mix between the two species, but its mitochondrial DNA—a secondary set that animals inherit only from their mothers—was entirely narwhal. “A while back, we presented our findings at a conference of 150 people who are very into belugas, and you could hear a pin drop,” Lorenzen says. “None of them were familiar with hybrids between those two species.”"
The cuttlefish and its relatives, squid and octopuses, often strike human observers as floating aliens wreathed in sucker-covered limbs — boneless, squirming appendages that would seem to have nothing in common with our own arms and legs.#Biology #Nature #Evolution #Genetics #Cephalopods
But hidden under the superficial differences, a new study shows, are some profound similarities: Human and cuttlefish limbs develop under the direction of the same genes. The new study, published on Tuesday in the journal eLife, lends weight to the theory that many animal appendages, from insect wings to fish fins, share a long evolutionary history.
It’s possible that the common ancestor of cuttlefish, flies and humans had limbs of some sort. Perhaps the animal used these genes to map the coordinates in other three-dimensional body parts, even one located entirely inside the body.
In later generations, animal lineages evolved profound differences. When it comes to limbs, flies and other insects are as different from cephalopods as they are from us. They have hard exoskeletons, with muscles pulling on them from the inside.
But every time a new kind of limb evolved, it seems, animals did not need a new way to tell cells where they were located inside it. Evolution reused the same genetic program over and over again.
“We’re looking at something ancient,” Dr. Cohn said.
Killifish manage to endure a variety of environments. The wee freshwater fish survive in isolated desert pools, lakes made by flood water, even seasonal ponds that are little more than puddles.#Science #Biology #Fish #Birds #Nature #Biodiversity
One place scientists didn’t expect to find them was in swan poop. But an international team of researchers reported last week in the journal Ecology that whole killifish eggs make it through the digestive tract of water birds intact, with one egg in the study even hatching more than a month after its transit through a swan. The findings suggest that bird feces may be capable of carrying fish eggs far from their original locations.
The researchers are planning a similar experiment now that uses eggs from carp, which hatch much faster than killifish. As killifish and carp can be invasive species outside of their normal range, understanding how they spread can help in containment.
Yonggang Nie and Fuwen Wei of the Chinese Academy of Sciences have spent years tracking wild pandas, analyzing exactly what kinds of bamboo they eat, and measuring the chemicals within those mouthfuls. And they found that the nutrient profile of a panda’s all-bamboo diet—very high in protein, and low in carbohydrates—is much closer to that of a typical carnivore than to that of other plant-eating mammals. “It was a surprise,” Wei says. Nutritionally, “bamboo looks like a kind of meat.”#Biology #Nature #Evolution #Pandas
In other words, “the giant panda does what human vegetarians do,” says Silvia Pineda-Munoz of the Georgia Institute of Technology. “We have high protein requirements, so we wouldn’t be able to survive if we just ate kale salad. Thus, we choose to eat tofu, beans, nuts, and other plant-based foods that compensate for the protein we aren’t getting from animal products. In the end, vegetarians and nonvegetarians don’t have such different diets when it comes to nutrients.” And so it is with China’s black-and-white bear.
This suggests that the move from meat to plants might have been easier for ancestral pandas than commonly assumed. By simply choosing parts of plants that are richer in protein, they could switch to vegetarianism without needing to radically overhaul their bodies. “If you’re going to switch to a specific plant, bamboo isn’t too bad, as it does have respectable plant protein levels, as well as a swath of different vitamins,” says Garret Suen of the University of Wisconsin at Madison.
These results should help to counter the tiresome myth that pandas are evolutionary dead ends: lazy, poorly adapted creatures that eat deficient diets, are inept at sex, and should be allowed to go extinct. Nonsense. Pandas have beautifully adapted to eat an extremely plentiful food source—bamboo—and they go to great, careful lengths to get exactly the right balance of nutrients.
Designing materials from scratch to produce blue is difficult even today, Subramanian says. "So much chemistry has to come together," he says. Subtle changes in the arrangement of neighboring atoms can throw off the energy levels of an atom's electrons, altering the color it can absorb. The red of rubies and the green of emeralds both spring from chromium ions surrounded by six oxygen atoms; other atoms in the two stones cause the color difference by altering the chromium's energy levels. Such effects are very hard to predict, Subramanian says: "If rubies and emeralds did not exist in nature, no one would know how to create them."#Science #Biology #Chemistry #Colours #Blue
But scientists have not given up hunting for new blues, continuing an age-old quest with 21st century tools. Although Subramanian's discovery came about by accident, other researchers are methodically using physics, chemistry, and genetics to find or create new blues for painters to dazzle with, edible colorants that make food more interesting, and blue flowers that, so far, only exist in artists' imaginations.
Conventional wisdom holds that earthworms head to the surface after rain because they can’t breathe. This is still taught to schoolkids, and you can find a lot of detailed explanation online. Most claim that worm trails and air pockets underground become submerged, and the earthworms can’t breathe. It makes sense.#Science #Research #Biology #Earthworms #Invertebrates
Most researchers, though, dispute this explanation. As Chris Lowe, a researcher at the University of Central Lancashire, points out in Scientific American, earthworms breathe through their skin and require moisture to do so.
Humans drown when their lungs fill with water. This is not possible for earthworms as they lack lungs. Multiple studies have also shown that most earthworm species can survive being submerged in water for two weeks or more.
Lately, most popular scientific accounts write off the “drowning worm” idea as a myth. While it is certainly not likely the entire explanation, perhaps we shouldn’t entirely rule it out. Research published in the journal Invertebrate Biology, for instance, found that worm behavior following rain depended on the species.
There undoubtedly will be new research and new revelations about the lives and habits of earthworms. Nature’s mysteries are not just “out there” in the wilderness. The common creatures that live around us still hold surprises. Take a moment and observe the phenomenon happening in the natural world, right now, where we live. The surprises and wonders are right under our feet."
A century ago, a strain of pandemic flu killed up to 100 million people—5 percent of the world’s population. In 2013, a new mystery illness swept the western coast of North America, causing starfish to disintegrate. In 2015, a big-nosed Asian antelope known as the saiga lost two-thirds of its population—some 200,000 individuals—to what now looks to be a bacterial infection. But none of these devastating infections comes close to the destructive power of Bd—a singularly apocalyptic fungus that’s unrivaled in its ability not only to kill animals, but to delete entire species from existence.#Biology #Nature #Environment #FungalDisease #Amphibians #Disease
Bd—Batrachochytrium dendrobatidis in full—kills frogs and other amphibians by eating away at their skin and triggering fatal heart attacks. It’s often said that the fungus has caused the decline or extinction of 200 amphibian species, but that figure is almost two decades out-of-date. New figures, compiled by a team led by Ben Scheele from the Australian National University, are much worse.
Scheele’s team estimates that the fungus has caused the decline of 501 amphibian species—about 6.5 percent of the known total. Of these, 90 have been wiped out entirely. Another 124 have fallen by more than 90 percent, and their odds of recovery are slim. Never in recorded history has a single disease burned down so much of the tree of life. “It rewrote our understanding of what disease could do to wildlife,” Scheele says.
“There’s no obvious way to deal with this,” Lips says. Some researchers have set up captive-breeding programs to buy time for species in contaminated habitats. Others are looking at ways of manipulating the fungus, or breeding more tolerant frogs, or pairing the frogs with defensive bacteria, or relocating frogs to sites that are inhospitable to the fungus. None of these solutions is a silver bullet, and none is close to readiness. “It says a lot about the scary nature of the disease that even after intense, long-term collaborations we haven’t come up with a viable solution,” Lips adds."
Gallery: What happens when you mix math, coral and crochet? It’s mind-blowing
How two Australian sisters channeled their love of STEM and coral reefs into the most glorious participatory art project.
It is a truth universally acknowledged among virologists that a single virus, carrying a full set of genes, must be in want of a cell. A virus is just a collection of genes packaged into a capsule. It infiltrates and hijacks a living cell to make extra copies of itself. Those daughter viruses then bust out of their ailing host, and each finds a new cell to infect. Rinse, and repeat. This is how all viruses, from Ebola to influenza, are meant to work.#Biology #Viruses #Replication #Nature
But Stéphane Blanc and his colleagues at the University of Montpellier have shown that one virus breaks all the rules.
Faba bean necrotic stunt virus, or FBNSV for short, infects legumes, and is spread through the bites of aphids. Its genes are split among eight segments, each of which is packaged into its own capsule. And, as Blanc’s team has now shown, these eight segments can reproduce themselves, even if they infect different cells. FBNSV needs all of its components, but it doesn’t need them in the same place. Indeed, this virus never seems to fully comes together. It is always distributed, its existence spread between among capsules and split among different host cells.
“This is truly a revolutionary result in virology,” says Siobain Duffy of Rutgers University, who wasn’t involved in the study. “Once again, viruses prove that they’ve had the evolutionary time to try just about every reproductive strategy, even ones that are hard for scientists to imagine.”