On December 11th, 2017 we learned about

Florida raptors show surprising resilience in their rapid recovery against invasive snails

The arrival of an invasive species is usually terrible news for an ecosystem. History can offer plenty of examples of plants or animals arriving in a new place, only to out-consume everything that had previously lived there, as no predators are prepared to help keep populations in check. Humans have tried curbing these conflicts by introducing new creatures meant to go after the invaders, but our efforts don’t have the best track record either. All this makes the story of North American snail kites rather surprising, as the native birds have apparently been able to survive, and even take advantage of, snails that would otherwise be wrecking havoc across the Florida Everglades.

Snacking on apple snails

North American snail kites (Rostrhamus sociabilis) live in various locations around the Gulf of Mexico, including parts of Florida. With sharp talons, a long, hooked beak, dark plumage and crimson eyes, these raptors look ready to take on anything. In reality, they’re only interested in one thing, which is the small apple snails they find in wetlands. While they’re capable of feeding on small turtles and rodents in a pinch, the kite’s usual tactic is to hold a snail in one claw while using their long beak to pick flesh out of the mollusk’s shell. As their name implies, snail kites are specialists, which is why ecologists were so worried when their narrow menu options became threatened by…other snails?

Oddly, the invasive species that was encroaching on the apple snails and thus threatening the snail kites was another species of apple snail. However, the South American apple snail grows much larger, making them harder to prey on. This left them more or less unchecked, allowing them to quickly cause billions of dollars worth of damage to the ecosystem, from hurting bird populations to eating plants that normally helped prevent algae blooms. Predictions were grim for the kites and the ecosystem in general.

Getting bigger, faster

Amazingly, the snail kites have found a way to rebound. Their population has grown, as have their bodies and beaks. The birds are now growing eight percent larger than they used to, with some growth spikes reaching as high as 12 percent. They seem to be benefiting from eating the larger snails as prey, but bigger meals alone don’t explain all the changes researchers have witnessed. In less than two generations time, the surviving kites are already showing a bias towards genes that grow larger beaks. It’s easy to see how bigger beaks allows the kites to scoop food out of bigger snail shells, but the rate that these changes are taking place are startling.

Natural selection is continuous process, but it usually operates on longer time-scale in larger animals. It’s easy to witness change in something like bacteria, which can propagate beneficial mutations across multiple generations in 24 hours. The snail kites, on the other hand, live to be eight years old, and so the larger birds with bigger beaks have somehow boosted their real and proportional numbers in less than two life spans. Researchers don’t necessarily think that the snail kites will now reign in Florida’s apple snail problems, but they do feel optimistic for the future of the raptors, which are now estimated to have a population over 2,000 for the first time in ten years.

Source: Things Looked Bleak Until These Birds Rapidly Evolved Bigger Beaks by Douglas Quenqua, New York Times

On December 10th, 2017 we learned about

Sorting through the spectrum of what chimpanzees regard as repulsive

You might not want to eat while reading this. According to a recent study that aimed to gross out chimpanzees, text probably isn’t enough to trigger the sense of disgust we’ve inherited from our ancestors. With that said, stories that bring up the issue of coprophagia, or eating feces, probably isn’t great for one’s appetite. At least not a first.

Digging into the details of disgust

Researchers were investigating where chimpanzees, as our closest genetic relative alive today, draw the line with what they’ll put in their mouths to eat. That line certainly wasn’t clear from the outset, as wild chimps will pick seeds out of poop to eat, and captive chimps will go a step further and snack on their poop outright. Researchers learned that there was some nuance to chimps’ consumption of crap, as the animals apparently evaluate feces based on genetic familiarity. A chimpanzee will eat their own poop, or that of closely related family members, but any other chimps’ waste elicits a clear display of disgust.

With that baseline established, researchers set up experiments to further probe chimpanzees’ criteria for when food is too revolting to eat. In one scenario, food was placed in an opaque box, either on top of soft but edible dough, or on top of a piece of rope. Chimps reaching in for the food were obviously repulsed by the soft, moist dough, yanking their hands out of the box as if it bit them. Other tests involved food being placed on what looked like feces, or near the scent of blood, and while no response was apparently quite as disgusting as something soft, wet and squishy, the chimps seemed to have similar guidelines for what was gross that humans do. They didn’t necessarily have the same standards though, as they would sometimes end up eating food from disgusting sources, but overall their criteria was pretty relatable.

Finding the value in what chimps find foul

The fact that these chimpanzees get grossed out like we do may seem obvious, but it wouldn’t have been safe to automatically assume they operated on similar criteria to humans. After all, any degree of coprophagia is probably too disgusting for humans to seriously consider, and researchers wanted to see exactly what our species had in common with our fellow primates. Avoiding substances, like poop or blood, that could easily harbor pathogens makes sense as a survival tactic, and identifying commonalities indicates that chimps and humans likely inherited some of these reference points from a shared ancestor. This work may also help zoos and conservationists manage the health of chimpanzees in their care. Dangerous substances can be presented in a more disgusting manner, and individual chimps that seem too casual about gross sources of food can be given extra attention for exposure to pathogens.

Source: What grosses out a chimpanzee? The origins of disgust by Kyoto University, EurekAlert!

On December 10th, 2017 we learned about

The invention and improvements that led to the modern roll of toilet paper

If you’re old enough to read these words, you’re probably at a stage in your life where you can take things like toilet paper for granted. Using your annual quota of 50 pounds of toilet paper per year may feel easy, but like any tool, it’s something you had to be taught to use and understand (as my four-year-old is now acutely aware of.) Beyond our acclimation to wiping ourselves with paper products, there’s been technological innovation in toilet paper as well, starting with the invention of paper itself.

Early years of paper hygiene products

Just a few hundred years after paper was invented in China, their revolutionary material for writing found its way into someone’s toilet. In 589 AD, the first account of using paper for personal hygiene was documented in Korea. By 1391, paper was being produced in China for the express purpose of wiping one’s rear. That paper came in awkwardly large sheets, around two- by three-feet overall, but at least had some perfume in it to make the experience more pleasant. It wasn’t an immediate world-wide hit though, partially because these tissues were intended for the emperor’s family only. Paper was still too precious for most people to dispose of after a single use.

This early start certainly didn’t put toilet paper, scented or unscented, into everyone’s bathroom. For many parts of the world, paper was scarce enough that it wasn’t even being used in books, much less in toilets. Instead, many folks made (or continue to make) due with a variety of options that many of us wouldn’t really associate with wiping. Throughout history, the list of bathroom tissue alternatives has included stones, sponges, clay, moss, shells, sticks, hands and corncobs.

Building a better toilet tissue

By the 17th century, paper products started making their way into the bathroom in the western world, but only after it arrived in the mailbox. Newspapers and magazines were repurposed as toilet paper in the American colonies, since paper was finally cheap enough to be disposable. Dedicated toilet paper was made available in 1857 by a one Joseph Gayetty, but it faced stiff competition in the form of the Sears Roebuck catalog. The latter was mailed out for free, and came with a hole punched in the corner, making it convenient to hang in one’s outhouse. This interest in convenience may have informed the next big innovations toilet paper technology, as in 1871 Seth Wheeler started selling perforated sheets in a role rather than a tissue-style box.

That doesn’t mean the story of toilet paper was settled in 1871 though. It wasn’t until 1935 that Northern Tissue offered “splinter free” paper with a process called linenizing, reminding us of how much bravery a trip to the lavatory once required. Two-ply tissue arrived in 1942, and colored paper was available in 1954. As important as all these improvements were, toilet paper’s place in public awareness was also being updated in this time period, since at one point the whole concept of wiping one’s self was deemed too inappropriate to even bring up, much less purchase in a public setting.

Selling toilet paper to an uncomfortable public

While Joseph Gayetty was proud enough of his medicated tissues to put his name on every one, other manufacturers were a bit more hesitant to brag about their products. Thomas Seymour, Edward Irvin and Clarence Wood Scott started producing rolled toilet paper, but sold it directly to hotels and drugstores, putting their clients’ names on them instead of their own. The Scott Paper Company didn’t really acknowledge their toilet paper production until 1896, over a decade after they started selling it. At the end of the 19th century, homes started being built with indoor plumbing, meaning older methods for hygiene, like corncobs, weren’t acceptable anymore. This gave toilet paper an opening in public discourse, since the product could be advertised for how well it broke apart in plumbing, avoiding too much detail about what it did directly for consumers themselves.

The final innovation on this front came from the Hoberg Paper Company in 1928. The company started selling their toilet tissues in “ladylike” packaging, since bragging about softness and feminine qualities would be easier than getting into the specifics of cleaning one’s nether-regions. When coupled with paper sold in four-packs, the branding was enormously successful, helping keep Charmin afloat through the Great Depression and beyond. They’ve had a number of major advertising campaigns since, but they’ve all been based around notions of soft, tactile enjoyment without getting too specific about where you’re supposed to actually feel that softness. Even though toilet paper use is growing worldwide, it’s still not something most of us (over age four) want to discuss in great detail.

Source: Who Invented Toilet Paper?, Toilet Paper History

On December 7th, 2017 we learned about

Elephant feet provide context in studies of extinct sauropods’ footprints

To understand how extinct dinosaurs functioned in the world, paleontologists often look to living animals for examples of how similarly built creatures put their modern anatomy to use. For example, the thick, columnar legs of an elephant seem like a good reference point for how ancient sauropods might have lumbered around.  Looking beyond bones, researchers are thinking that modern elephants can also be a reference point for trace fossils, like footprints made back in the Mesozoic era. While sauropod dinosaurs haven’t shared a direct ancestor with elephants for over 100 million years, the hope is that the similarity in their ecological niches as giant herbivores will carry over into other aspects of each animal, right down to the bottom of their feet.

In South Korea, a fossilized footprint revealed a very specific similarity between elephant and sauropod feet. The trace fossil footprint was covered in a sort of honeycomb-shaped pattern, as soft mud crept into the cracks of the dinosour’s feet way back in the Cretaceous period. The resulting texture shows the dinosaur’s feet were covered in hexagonal scales across their soles, looking strikingly similar to the natural tread found on an elephant’s feet. It’s hard not to assume that this was a case of convergent evolution, with both large herbivores evolving the same “solution” to keeping thick, heavy limbs from slipping as they walked through soft soil or wet mud.

Inferring size from a foot’s impression

A second study looking at sauropod footprints wasn’t focused on the texture of the dinosaur’s soles as much as what those prints could tell us about the animal as a whole. Starting with the simple premise that heavier animals will make deeper footprints, researchers measured fossilized tracks and then simulated the forces that would be needed to make different sizes of footprint. Once a match could be made between simulated feet and the depth of actual fossilized prints, researchers could then calculate just how much the original sauropod must have weighed to sink that far in the soil.

To validate this method, they turned to elephants as the closest living approximation for extinct sauropods. Researchers used the same techniques developed around fossilized prints on fresh elephant footprints, since they could then verify the living elephant’s weight. In the end, the simulated footprints weren’t perfect, but with a margin of error of around 15 percent, they were at least as close as other methods for estimating dinosaur mass. For example, estimates for a dinosaur’s size may be made calculating the animal’s volume based on bone sizes, which in turn is often based on living animals as reference points. The hope is that estimates based on footprints can be refined to become more accurate, particularly in regards to the physics that control soil movement.

Restraint in using elephants as reference points

Other researchers question the validation aspect of this technique though, since we can’t be sure if elephants really are the best reference point for animals that could grow to be close to 100 feet long and probably weigh ten times more than the largest living pachyderm. Differences in leg movement, for instance, could change how weight is distributed across a dinosaur’s heels and toes, which could affect how deep a foot presses into the dirt. These critics aren’t advocating that giraffes or rhinos would necessarily be a better model organism, but that we should be careful about assuming too much about how sauropods were built and moved, even if their feet now seem so familiar.

Source: Can fossil footprints reveal the weight of a dinosaur? by David Moscato, Earth Magazine

On December 7th, 2017 we learned about

Robotic tractors will soon be adding more automation to building construction

Something people don’t tell you about parenthood is how much time you have to spend lurking around construction sites. Something about the preschool brain finds huge pieces of machinery rather mesmerizing, leading to mornings where a walk or bike ride has to be put on pause so you can watch just how cool excavators really are. Workers on job sites have been pretty welcoming as well, often answering questions or just sharing my kids’ appreciation for what a bulldozer can do. Some of this dynamic my change in the near future though, because a company called Built Robotics is looking to change the scheduling of construction, and maybe even get rid of some of the folks who currently control major machines.

Unmanned machinery

Right now, Built Robotics is starting small, working on turning a standard Bobcat skid loader into an autonomous robot. Ideally, the small tractor will be delivered to a site and given instructions about the size of the future building, at which point it will start scraping out a foundation pit on its own. It will navigate the space using a combination of GPS and LIDAR, the same laser systems employed by robotic vacuum cleaners to figure out the shape of your living room. It’s a bit trickier for these robotic tractors though, since if they’re doing their job, they’ll be constantly changing the shape of the space around them, which makes establishing navigational reference points a little more complicated.

Once all these technical challenges are smoothed over, a robotic tractor promises to do the same work as people, but in a more compact schedule since nobody would necessarily be limited to the schedules a human being finds comfortable. It would also remove some humans from the job site, meaning there would be fewer people at risk of injury, which is an attractive notion. Some of those people might still be needed to help manage the robotic tractors, but only if they’re up tackling a new set of specialties.

Effects of automation

From my four-year-old’s perspective, the coming wave of robotic tractors is kind of a mixed bag. On one hand, it’s a combination of tractors and robots, which is cool by definition, even if those tractors can’t also transform into humanoid warriors. On the other hand, if these tractors are somehow quiet enough to work all hours of the day without bothering the neighbors, construction will no longer be on a preschool-friendly schedule. The compressed building schedule will probably be appealing to everyone who wants to use the resulting building, but it’ll leave us much less time to stop and gawk.

Source: This Robot Tractor Is Ready To Disrupt Construction by Matt Simon, Wired

On December 6th, 2017 we learned about

Halszkaraptor escuilliei, the first known dinosaur (partially) adapted to an aquatic lifestyle

It wouldn’t really do Halszkaraptor escuilliei justice to say the newly described dinosaur “broke the mold,” because this unusual animal seems to have been the product of three or four molds mashed together. While technically a theropod dinosaur, like Tyrannosaurus or Velociraptor, H. escuilliei followed very few of the anatomical conventions laid out by its relatives. Instead, the resident of what is now Mongolia sported features only seen on more modern relatives, like the neck of a swan, or the upright posture of a duck. The overall package was so unusual that paleontologists studying H. escuilliei‘s fossils weren’t even sure it was a legitimate specimen when it was first presented to them.

An artificial amalgam, or just really odd?

Paleontologists usually find fossils themselves, either in the field or at least in a museum’s archives. Appropriately for such a weird species, H. escuilliei was handed over to researchers at the Royal Belgian Institute of Natural Sciences after it was purchased from smugglers on the black market, with the eventual goal of repatriating it to Mongolia. This sordid history, plus the strange mix of anatomy, necessitated extra scrutiny to make sure the 15-inch block of stone contained fossils from one animal, as fossil poachers will sometimes glue fossils together to basically fabricate a more exciting specimen. Since H. escuilliei already looked like a mix of at least two to three animals, researchers felt it warranted a trip to the European Synchroton Radiation Facility (ESRF).

Using the multi-resolution tomographic scanning, researchers were able to comb over every inch of the fossils and rock that contained the specimen. Rather than finding suspicious cracks and glue, the high-energy x-rays from the synchroton showed that the bones were consistent in their composition throughout the skeleton. This confirmed that the skeleton had not been altered by humans, and was simply exotic looking due to evolution.

Mostly set for going swimming

The synchroton also allowed researchers to assemble a highly detailed, 3D digital model that let them examine details without damaging the rock or fossils in the process. Peering through the 3D structure, they found an unusual number of skinny teeth towards the front of H. escuilliei’s mouth. Scans also revealed spaces for a network of sensory nerves, reminiscent of a crocodile’s sensitive snout. The nostrils were located higher on the snout than most ancient theropods, placed in a location closer to where you’d find them on a modern duck. Finally, the head was noted for being especially triangular overall, all of which seemed to indicate that H. escuilliei wasn’t running down food on land like its kin, but was instead snatching fish from the water.

Imagining H. escuilliei moving through the water was a little weirder than figuring out how it fed. The dinosaur had an elongated, flexible neck which has been compared to a swan’s. However, the arms certainly didn’t allow for flight like many waterfowl today, and they weren’t quite as specialized as a penguin’s flippers either. The fingers were elongated differently than other ancient theropods, instead looking like the shape of a bird like a murre. Researchers suspect that these forelimbs were used like paddles in the water, although without more information about the shoulders, it’s hard to know how well they could really move. At the very least, the feet and legs don’t match the efficient webbed feet found on a modern duck or goose, instead being more suited for simply walking around on land.

Aquatic but kind of awkward

The overall impression of H. escuilliei seems to be a jack-of-all-trades, and master of none. The dinosaur was at least partially equipped for the water, but not completely committed to it to the degree modern shorebirds are. The small predator could walk around on land, but probably collected most of its food paddling around lakes or swamps. This may indicate that H. escuilliei’s environment was in a state of flux, and that the water it preferred wasn’t always available. As a result, it still had to be ready to walk to the next pond to look for more fish.

Finally, the last weird thing about this dinosaur is that it’s weird at all. Mammals can be found in the air, in trees, underground, and in the oceans. Dinosaurs came in all shapes and sizes, ruling the Earth for millions of years, but somehow skipped going for a swim in all that time. We don’t find many theropods in the shape of H. escuilliei, but this creature’s existence begs the question as to why that is. Are more aquatic species still waiting to be discovered, or did dinosaurs have some other reason to avoid committing to living on the water?

Source: Apparently This Is What a Swimming Dinosaur Looks Like by Ed Yong, The Atlantic

On December 6th, 2017 we learned about

Newly discovered black hole is bafflingly large for being 13 billion years old

When you look at stars in the night sky, you’re not only seeing light from another place, but another time. Space is so vast that even light, moving at the fastest speed we can imagine, takes ages to reach our planet from other parts of the universe. So if you look at our solar system’s closest neighbor, Alpha Centauri, you’re seeing the light emitted by that star over four years ago. Bigger distances thus yield bigger gaps in time, which is how astronomers recently found evidence of a black hole from 13 billion years ago, long before the Earth, or most other planets, even existed.

Finding darkness in ultrabright objects

The light that was detected by wasn’t coming directly from the black hole itself, as those intensely massive objects don’t emit or reflect any light to see (hence their name). Any object that gets too close gets pulled into the black hole, but all that gravity is good for collecting a looser assortment of material in the immediate space around the black hole as well. In the case of this ancient black hole spotted by astronomers, they knew it was there it was surrounded by an ultrabright quasar, a cloud of energy-emitting particles orbiting the black hole at close to the speed of light.

By analyzing the light coming from quasar J1342+0928, the following profile of the black hole was put together. The supermassive black hole was around 800 million times the mass of our Sun, which isn’t surprising since it would have to be large to support a quasar around it. However, when combining that size plus its age, scientists started scratching their heads. How did such huge collection of mass exist only 690 million years after the Big Bang created our universe?

What existed in the early days of the universe?

As far as everyone could understand, there shouldn’t have been that much material in one place to form a giant black hole that early in our universe’s history. The current model is that after the Big Bang occurred, matter was first very energetic, but then calmed down into mostly neutral hydrogen atoms. Each proton and electron pair was balanced, and had no need to interact with its neighbors, meaning no energy was being released anywhere. This time in the universe’s history is known as the Cosmic Dark Ages, because no stars yet existed to emit any light. Everything was essentially inert.

Eventually, gravity started stirring things up. Particles began to clump and collide, forming larger atoms and reactions. New elements were created for the first time, as did collections of mass with enough nuclear activity to start emitting energy, becoming the first stars. As it happens, the light from the newly discovered quasar J1342+0928 was emitted at this time, meaning it existed when the entire concept of “stars” was just getting started.

Too old to be so big?

Which brings us back to how weird this timing is. The nuances of the light from quasar J1342+0928 help narrow down the date of the so-called Cosmic Dawn, but also raises new questions about what the state of the universe was at that time. If stars were still forming for the first time, how was enough matter somehow rounded up already to form a black hole 800 times bigger than our Sun? Smaller black holes are normally created from the collapse of a star, not congealing dust. This doesn’t necessarily contradict the model for the universe’s maturation, but instead has astronomers looking for new ways for black holes to form.


My four-year-old asked: What would happen to a person sucked into a black hole? To a car? To a house? To a… (etc.)

In almost every case, once that object got close enough to the black hole, crossing the so-called event horizon, it would be ripped and stretched to the center of the gravity-producing mass. For instance, if you fell in feet first, your feet would be yanked downwards harder than your head, although overall the experience would probably be very short, as you’d be pulled apart into a molecular “piece of spaghetti” before being crushed into the black hole itself. You’d technically be adding more mass to the black hole too, making it ever-slightly bigger than it was before.

 

Source: Scientists observe supermassive black hole in infant universe, Phys.org

On December 5th, 2017 we learned about

Pigeons parsing time and space suggest that our brains might not be as special as we thought

Thanks to a test of pigeons’ sense of space and time, researchers may be casting doubts on the evolution of human brains. That’s not a knock on the people studying pigeons— these birds are capable of a lot, right down to helping diagnose cancer. The issue is that the birds seem to have a quirk in their perception that has previously only been seen in primates like us. It’s been understood to be tied to the specific structures in our brain that assist with processing spatial and temporal information, but that can’t be the case with these pigeons, because their brains simply don’t have any of the structures in question.

How long is a line, and how long does it last?

The first phase of this test trained pigeons to watch a screen, and then poke a response on a touch screen in order to earn a snack. When looking at a two-inch line and a nine-inch line, they needed to select the longer option. When lines were flashed on the screen for either two or eight seconds, the birds needed to choose the shape shown for the longer duration. This was nothing to sneeze at, but it was only the training for the real testing in phase two.

Once the pigeons seemed comfortable with looking for lengthy lines for longer time periods, researchers complicated their task by mixing in more intermediate choices. Instead of the seven-inch difference between the first sets of lines, the birds now had to consider lines that were only off by one inch. The attribute that was being tested was also less clear, with length and duration both being tested at random. This forced the birds to really pay attention to both space and time, which lead to some interesting blurred lines in their perception.

As the pigeons progressed, a pattern emerged that showed how their brains handled this spatial and temporal information. When the birds saw a longer line, they were also likely to react to it as if it were on screen longer. The reverse was true as well, with lines displayed for longer amounts of time apparently appearing lengthier to the pigeons as well. It may sound strange on paper, but as a primate you’re probably more familiar with this than you might think, as we do this too. The major difference is that we do it thanks to both types of information being processed in the same place in our brains— the parietal cortex in our cerebral cortex. Without such a structure to mash that information together, why does pigeon perception seem to work the same way?

Explaining the overlap in pigeon perception

There are two hypotheses at this point, and both of them reduce the prestige of a primate’s parietal cortex. The first hypothesis is that pigeons, and probably other birds as well, evolved similar cognitive abilities independently of mammals, essentially reproducing what our primate brains do in these tests, right down to the errors. This kind of functional overlap does occur in what’s called convergent evolution, but not usually to this degree of specificity. The strikingly similar overlap in pigeons’ spatial and temporal perception has with primates seems unlikely to have occurred by chance, particularly without any clear evolutionary benefit to promote its growth in two family trees.

The second explanation is that this mental circuitry evolved once, long ago in a common ancestor, and bird and mammal brains have just packed it into different structures in our brains. So instead of using a parietal cortex, those circuits, quirks and all, were packed into birds’ palliums instead. The catch here is that mammals haven’t shared an ancestor with birds for millions of years, meaning this specialized perception has been getting passed down through a lot of different species, well beyond the chimpanzees and pigeons we’ve tested. Since the underlying structure that handles this thinking might not be exclusive to primates, it suggests that some of our amazing cognition just needs to be properly tested in other animals.

Source: Pigeons can discriminate both space and time, Iowa Now

On December 5th, 2017 we learned about

Your body’s circadian rhythm changes the composition of your muscle cells’ membranes

Circadian rhythms are usually associated with sleepy brains, but it looks like our muscles have a daily routine as well. As the day ticks on, researchers have found that the mixture of lipids, or fats, in our muscles regularly change, regardless of activity levels. This doesn’t necessarily mean that you’re likely to feel weaker or stronger at different times, but it may have implications for other parts of the body, like your liver or fat cells.

Measuring muscle cells

The first phase of this study simply measured the composition of lipids in people’s thigh muscles throughout the day to see if it changed on a regular cycle. Every four hours, a small muscle sample was taken and analyzed. As expected, the lipids found in a single thigh varied according to a 24 hour schedule. However, they also varied greatly between individuals, which muddled things up a bit. To try to really isolate the relationship between lipid composition and circadian rhythm, researchers decided to isolate the muscle cells themselves.

The second phase of the experiment was based around muscle cells living in a petri dish. This allowed for finer control over variables, such as the signals that would normally put muscle cells on a daily rhythm in the first place. A circadian rhythm was then simulated by exposing the muscle cells to signal molecules that the body normally produces on a daily basis. As expected, this triggered the changes in lipid composition that matched what had been previously observed in people’s thighs. To further prove the importance of this signal molecule, genes in the muscle cells that enabled sensitivity to circadian signals were blocked, and the signal molecule no longer affected lipid production.

Interfering with insulin intake

You probably haven’t noticed these changes in your muscles’ lipid production, but your liver and pancreas might have. Lipids are make up part of a cell’s outer membrane, and thus can influence how well substances can pass in and out of a cell. This balance is disrupted in insulin resistant cases of type 2 diabetes, reducing muscle cell’s ability to take in blood sugar. Knowing that the lipids that influence insulin absorption change throughout the day may enable more sophisticated treatment methods. The circadian signaling molecules in our bodies, the treatment that’s a good match for someone’s morning might not be as effective in the evening.

Source: Our muscles measure the time of day, Universite de Geneve

On December 4th, 2017 we learned about

Organisms prepare for danger by picking up on specific smells

Growing up, we’re taught to look and listen for dangers in the world around us, from oncoming traffic to fire alarms. As humans, we generally gloss over things like smell, because these other senses are just so central to our experience. Our experience, however, isn’t universal, and plenty of other organisms do use their sense of smell for these tasks, sniffing for signs of trouble before it’s upon them. It’s actually such popular way to survey one’s local environment that life forms that lack a proper nose even rely on smell as a way to stay safe, or at least prepare for the worst.

Preemptive protection for plants

The tall goldenrod (Solidago altissima) is a plant that, as the name would suggest, grows up to four feet high and sprouts small, yellow flowers at its top. It’s popular with populating insects, but also with bugs that can cause it harm, like goldenrod gall flies (Eurosta solidaginis). The flies like to lay their eggs in the stem of the goldenrod so the larvae can hatch surrounded by their first meal. Their munching might not kill the plant outright, but they induce the plant to grow a gall, or protective casing around the larvae, that can strain growth and reduce the flower’s seed production.

To protect against the flies larvae, tall goldenrod have evolved a very specific defense system. A plant under attack will produce jasmonic acid, a compound that can reduce the amount of nutrition the larvae can gain from eating the plant, constraining their growth and theoretically limiting their impact. Researchers have confirmed that this defense mechanism can be deployed to greater effect if the plant can prepare in advance, particularly after smelling danger in the air. The exact scent they pick up is the mating pheromones of male E. solidaginis flies. While the flies use this scent to communicate their intent to reproduce, tall goldenrod can use it as a way to minimize the damage for the eventual offspring.

Roundworms bolster themselves against bacteria

The tiny roundworm Caenorhabditis elegans is a bit more mobile than your average tall goldenrod, but they use smell to prepare for danger in a similar way. Instead of worrying about fly larvae, the microscopic nematodes keep a nose, or smell receptor, out for the scent of a strain of Pseudomonas aeruginosa bacteria called PA14. Even though the worms are technically mobile, they don’t bother fleeing a sniff of bacterial byproducts, and instead prime their cells’ immune response. When they do come in to contact with PA14, the prepared roundworms are much more likely to survive the encounter than peers that are caught off guard.

While roundworm safety is great, research into this dynamic has been more focused on understanding exactly how it works on cellular and chemical level. Scientists first had to confirm that the worms were able to truly prepare in reaction to the smell of bacteria, and not just reacting to any stimuli. They exposed the roundworms to smells from various bacteria, and found that their “noses” were discriminating enough to only react to odors from more dangerous sources.

The mechanism that drives the preparation is called heat shock response, and is common to both plant and animal cells. When a stress, like changes in heat, salinity or other stimuli, is encountered, the cell creates specific proteins to do extra repair work in any damage that cell already has. That way it will be more likely to withstand new damage caused by the new threat when it starts causing trouble. While humans aren’t necessarily concerned about the same strains of P. aeruginosa the nematodes are, we might like to imitate their cell’s sense of smell to fight off other diseases or even symptoms of aging that do affect us.

Source: Worms learn to smell danger, EurekAlert!