On August 15th, 2018 we learned about

Anglerfish’s biolumincent bacteria retain a strange potential for independence

While they sport an impressive visage complete with bulbous eyes and a mouth full of spiny teeth, an anglerfish’s most famous feature doesn’t exactly belong to the fish itself. The small glowing bulb that hangs from a stalk growing out of the female anglerfish’s forehead only lights up because it houses a colony of bioluminecent bacteria. As these bacteria light up, they attract potential prey and mates for the fish, although the exact details of how both organisms benefits haven’t been fully explored. Even after sequencing the bacteria’s DNA, it would seem that the relationship may be a bit more complicated than your average bit of symbiosis.

Most symbiotic relationships involving bacteria fall into one of two categories. In the first, a host offers a home or other benefits to the partner organism, but that partner remains free and unchanged from it’s uncoupled counterparts. The second form of bacterial symbiosis includes significant changes to the bacteria’s DNA. Thanks to services supplied by their host, they no longer need to maintain all their own bodily functions, and can be absorbed to live in a hosts own cells. A widespread example of this kind of relationship is the chloroplasts in plant cells that are essentially cyanobacteria living as organelles in plants, enabling photosynthesis.

Incomplete integration

The genome of the bioluminencent bacteria in anglerfish suggests an unusual third option that seems to operate as a half-way point between the relationships described above. The bacteria have apparently been shedding some of their genes over time, but not as many as you might expect from an organism tied so closely to a 100 million-year-old fish like the anglerfish. Instead of being completely independent or assimilated, these glowing bacteria may be hedging their bets somehow, retaining some of the genes found in their free-swimming kin found elsewhere in the ocean. For example, they’ve lost the genes to allow them to detect all food sources but one. They can’t make their own amino acids, but they do still have the genes necessary to grow the tail-like appendage called a flagellum that enables other bacteria to swim through the water.

Overall, both the fish and bacteria are still helping each other. The bacteria help attract things the fish needs, and the fish then houses and helps feed the bacteria nutrients they can no longer come up with on their own. Still, researchers are curious how this particular balance came to be, and if it’s still a work in progress that will eventually leave the bacteria more fully integrated into the anglerfish’s own body.

Source: Glowing bacteria on deep-sea fish shed light on evolution, 'third type' of symbiosis by Krishna Ramanujan, Phys.org

On July 19th, 2018 we learned about

Without climate control, heat waves take a measurable toll on our cognitive abilities

On the hottest days of summer, I generally just feel like giving up. By later afternoon, temperatures in my older building easily surpass whatever’s happening outside, a factor compounded by the outdated myth that “nobody needs an air conditioner in northern California.” The net effect is a feeling of tired fogginess, making concentration on just about any task rather difficult. While this may sound like a lot of whining (it is!) scientists have actually been able to quantify the cognitive hit inflicted by seasonal spikes in heat, pointing out that they take a measurable toll on all of us.

Testing the effects of living in high temperatures

Unusually high temperatures associated with heat waves have long been known to be detrimental to human health, although most research on heat has focused on cases when it’s literally a danger to people’s lives. To investigate cognitive issues possibly experienced by everyone, researchers purposely skipped at-risk populations like infants and the elderly, working only with healthy college students. In theory, any issue that would affect a 22-year-old would probably be an issue for 30- and 40-year-olds as well. The only other criteria that mattered was whether or not each student had air-conditioning in the dormitory where they lived.

Every day of the study, test participants were asked to take a few cognitive tests when they woke up in the morning. The tests included tasks like quickly reading the names of colors with letters displayed in conflicting hues, which is a long-standing way to asses how well someone can filter relevant information in a hurry. They were also asked to do some math and memory tests, giving researchers a range of performance metrics to compare. To make sure environmental conditions were also comparable, test subjects’ rooms were outfitted with temperature, carbon dioxide, humidity and noise sensors. Physical activity and sleep were also tracked with a wearable device.

Extra time and additional errors

After five days of normal temperatures, there was a spike in the area’s heat index. Almost immediately, students living without air conditioning started showing a decrease in cognitive performance. They took 13.4 percent longer in deciphering the color words, and also had 13.3 percent more errors in their math tests. Even after the heatwave broke and the outside world returned to normal, much of that heat was retained indoors, extending the impact of overheated students’ low scores.

Anyone who has lived through unusually hot days won’t be surprised by this, but anecdotally hot homes don’t help science diagnose health problems shape policy. By measuring the significant impact heat has one people’s ability to handle cognitive tasks, this study reveals that rising global temperatures may be causing more immediate and widespread problems than people realized. It’s practical to demand air conditioning for every hot home on the planet, but we may need to further prioritize heat-shedding designs in future construction, plus look for ways to mitigate possible problems caused by people too hot to think clearly.

Source: Extreme heat and reduced cognitive performance in adults in non-air-conditioned buildings by Harvard T.H. Chan School of Public Health, Medical Xpress

On July 9th, 2018 we learned about

Prehistoric pink pigments found in fossils of world’s most ancient organisms

Beauty, and by extension coloration, is only skin deep. It’s a frustrating fact for paleontologists, who can often only guess at what colors extinct creatures like dinosaurs may have been millions of years ago. Allowing for a few unusual exceptions, it’s just very unlikely for the color-producing pigments from an animal’s skin to be preserved as a fossil. Unless, apparently, that organism is so ancient and simple that there was never skin to worry about, in which case we can say with confidence that some of the world’s original organisms were all pink.

This conclusion is the result of oil drilling in the Sahara Desert. Some of the extracted shale was found to contain microscopic fossils from 1.1 billion years ago, well before any multi-cellular organism ever wriggled or swam across the Earth. When analyzed further, researchers realized that the fossilized cells were preserved well enough to carry molecules from the organisms’ pigmentation, and that that pigment would have given each cell a light pink hue. That pink was likely part of an early version of chlorophyll, which helped researchers identify exactly what kind of organism produced it.

Large numbers, tiny size

Cosmetic concerns aside, these fossils were identifiable as an ancient form of cyanobacteria. Their concentration was high enough to suggest that these tiny organisms likely dominated their ecosystem to such an extent that they may have been holding other forms of life in check. Until algae really spread throughout the oceans, an ecosystem flooded with minuscule cyanobacteria wouldn’t have provided much nutrition for larger, more predatory organisms. In fact, they’re so small many have been appropriated in to larger organisms’ cells, making up the chloroplasts found in plant cells today.

More complex organisms still had a long time to wait though. These tiny, pink cells would continue to dominate the planet for another 450 million years after this particular batch started becoming fossils.

My fourth-grader asked: What are cyanobacteria? What were they eating then?

Cyanobacteria were likely the first organisms on the planet, and they’re still alive today. They generally live in water, and produce their own food through photosynthesis, which is why some now live in plants as mentioned above. Thankfully for the rest of us, cyanobacteria’s primary waste product is oxygen, meaning their metabolism is actually the reason we have air to breath today.

Source: Scientists discover world's oldest colour – bright pink by Luke Henriques-Gomes, The Guardian

On May 2nd, 2018 we learned about

The protein-based toolkit that lets bacteria keep building in the low temperatures of your refrigerator

You can’t avoid sharing your food. Even if you pack up your fruit, sandwich or pasta in closed container in your fridge to hide it from pets, kids and insects, it will eventually get nibbled on by bacteria clinging to its surface. Putting food in a refrigerator does help though, as the cold can greatly inhibit bacteria’s growth, minimizing just how many microbes you’ll risk ingesting when you finally get to your leftovers. Of course, anyone who has cleaned out a fridge knows that this protection is temporary, which is sort of weird if you think about it. If the temperature doesn’t significantly change when food is in a fridge, how do bacteria overcome the chill to eventually take a slimy bite out of your old casserole?

Making sense of a cell’s instructions

The first step to understanding how bacteria can beat the cold is figure out how the cold slows the bacteria. Inside bacterial (and other organisms’) cells, DNA is read by proteins to create a sort of working copy of the cells instructions, called RNA. Proteins called enzymes then go through the RNA instructions to build whatever new proteins the cell needs to perform its task, such as split and multiply across your cottage cheese. Making those enzymes is a lot of work, and bacteria seem to put about half their resources into creating them, just so they can do the other work the cell needs completed.

Lowering the temperature messes up this process in two ways. First, enzymes just function more slowly when they’re cold, so every step of a cell’s operation slows down. The second issue is that the RNA that’s used by enzymes to build new, functional proteins gets crumpled up, or “structured,” when it’s cold. Like a tangled set of Christmas lights, structured RNA is much harder for an enzyme to make sense of, and so it needs to somehow be relaxed into a looser configuration before it can be used.

Keeping counter-measures close at hand

To make that RNA usable, bacteria employ another set of proteins called Cold Shock Proteins (Csps). These help untangle the RNA to make it available to enzymes, but that’s only helpful if the Csps are available when a bacterium needs them. To prepare for unexpected swings in temperature, bacteria actually carry a lot of RNA instructions for Csp production, ready to deploy at a moment’s notice. This way they don’t have to unpack those instructions out of DNA, then RNA, then production to start dealing with the cold.

The instructions for Csps are essentially always kept at the ready, saving the bacteria time when temperatures drop. If that weren’t enough, researchers have found that the RNA that is used in Csp production actually reacts to temperatures in reverse. Unlike most of the RNA that needs rescuing from low temperatures, these instructions are crumpled and structured when the cell is warm, but relaxes for use when things get cold.

These specializations help bacteria bounce back from temperature changes that would otherwise immobilize them. Once the Csp RNA is in use, a bacterial cell will likely invest as much as 25 percent of its protein-building energy into making Csps alone. And this isn’t even the only way bacteria respond to cold temperatures- in some cases, pieces of overly-structured RNA are destroyed altogether to allow enzymes to get on with their work. So even though we can relax a little when we put our food in the refrigerator, the bacteria on our leftovers are doing their best to spring into action, engaging in a slow-motion race that we only notice when the bacteria win.

Source: Refrigeration slows – but doesn’t stop – food rot. Now scientists know why by Melanie Silvis, Massive

On April 26th, 2018 we learned about

Deciphering ancient diets from parasite DNA in people’s poop

Hopefully you’re not eating as you read this. If you are, however, future researchers may be able to figure out what you munching on, assuming you had some other organisms enjoying the meal with you. While not as widespread today, many meals can be unknowingly shared with parasitic worms in people’s digestive tracts. Those worms’ eggs are then… deposited in toilets, creating quite the treasure trove of data for researchers. A recent study of various ancient European latrines has even been able to recover DNA from digested food and eggs, adding a new level of detail to our understand of historical diets.

Deciphering dining habits from people’s dung

Researchers dug through toilets from the Middle East to Scandinavia, spanning not just geography, but time periods as well. From the 2500-year-old samples from Bahrain to more recent, 300-year-old poop from the Netherlands, they found that the majority of the parasitic eggs came from species that were transmitted directly between humans, such as pinworms. This wasn’t a huge surprise, as these parasites have specifically evolved to be easily passed between one person’s… unwashed hands to food very easily.

Knowing that people were in contact with other people wasn’t a huge insight, of course. More revealing was the number of eggs from parasites that don’t specialize in human infections. It’s suspected that these eggs were more likely picked up from eating under-cooked pork and fish that had been carrying parasites when they were alive. DNA tests also found revealed the non-worm portions of people’s meals, which generally supported notions of geographic trends in cuisine. For instance, cabbage and buckwheat turned up in northern Europe, while fin whales were apparently on the menu in medieval Denmark.

Tracking worms’ travel between towns

This isn’t the first study to dig through ancient people’s poop to identify components of their diets, but the use of so-called ‘shotgun’ DNA sequencing may open up new avenues of research. In many samples, the mitochondrial DNA was recovered from parasites’ eggs, in addition the nuclear DNA. Because mitochondrial DNA is (almost) only inherited from an organism’s mother, it can be used to trace specific family relationships over time. This means that researchers may soon be able to not only find parasites, but map out how and when they spread from one town to another. This can then help us understand a how people traveled long before they could meticulously document every moment and meal themselves.

Source: Parasite eggs from ancient latrines hint at people's past diets by Public Library of Science, Phys.org

On April 8th, 2018 we learned about

Investigating the likelyhood of microbial life existing in Venus’ upper atmosphere

You don’t want to live on Venus, but there are a lot of places you don’t want to live on Earth as well. Hydrothermal vents, acidic lakes and the cold reaches of the upper atmosphere are all pretty inhospitable plants and animals alike, but that doesn’t mean that they’re not home to life. As we look closer at the nastiest, hottest, most acidic bits of real estate on the planet, the more bacteria we find adapted to these extreme conditions. This has scientists excited, because if life is in the market for these spots on Earth, there’s a small but real chance that it might love what’s available on Venus.

Too hostile to be a home?

Don’t feel bad if you’re not familiar with the brutal conditions on Venus. It’s such a rough part of the solar system that the probes we’ve sent to the second planet generally don’t last very long; the Soviet Venera 13 set records by surviving for a whole 127 minutes. Aside from a few photographs, we have been able to determine that the surface of Venus gets up to 863º Fahrenheit, and the air pressure is between 17 to 20 times as strong as on Earth. With the wind and acidic chemistry in the air, even the heartiest Earth-born bacteria couldn’t survive on Venus’ surface. On the other hand, the upper atmosphere may be just gentle enough to allow microbes a small chance at survival.

The upper layers of clouds on Venus are reflective and acidic, made mostly of carbon dioxide, water and sulfuric acid. It doesn’t sound pleasant, but the temperatures are low enough that life as we know it could exist there. What’s more, the sulfuric acid may even be a byproduct of microbial metabolisms– species on Earth are already known to do that (often with unfortunate consequences for their surroundings.) What’s more, observations from space have noted unexplained dark patches in these Venusian clouds, most of which are within the size range of bacteria on our own planet. This isn’t proof of alien life, but since we’ve never tested specifically for organic chemistry in Venus’ upper atmosphere, we can’t rule out the possibility of microbes without getting more information.

While spacecraft are circling Venus in space, none of them are in a position to sample these dark spots in the planet’s clouds. One proposed design is the Venus Atmospheric Maneuverable Platform (VAMP), which would fly through caustic clouds for as long as a year. With the right set of sensors, like mass spectrometers and microscopes to examine airborne samples, researchers would be in a better position to identify potentially organic materials in the atmosphere.

Originating from the past, or other planets

As hard as it is to picture life on such a harsh planet, there are actually a few possibilities for how bacteria could end up there. The first option is that the bacteria migrated from the ground, since Venus was probably a nice place 2.9 billion years ago. At that time, there’s a fair chance that the planet was a tepid 51° Fahrenheit on the surface, giving microbes a chance to evolve before the upper atmosphere was the only place left to go. Alternatively, the clouds could have been seeded by a place like Earth, as high-speed dust moving through the solar system has been calculated to be able to knock microbes in our atmosphere clear into space. So if life didn’t arise on Venus on its own, there’s still a chance that other Earthlings simply beat us to the punch of traveling to another planet.

Source: Is there life adrift in the clouds of Venus? by University of Wisconsin-Madison, Science Daily

On March 27th, 2018 we learned about

Reshaping sugar crystals to reduce quantities while staying sweet

The average piece of milk chocolate is 60 percent sugar by weight. While your stomach and pancreas will need to process all those calories, there’s a chance that the bundles of sugar-sensitive cells on your tongue won’t actually taste it all. This has presented a bit of an opportunity for food scientists looking for ways to reduce the amount of sugar used in sweet foods, as they realized that less sugar can be used if more of that sugar will actually be tasted when you eat. So rather than add sugar substitutes like aspartame, researchers at Nestlé and startup DouxMatok have been trying to reshape the sugar itself so that it’s essentially easier to enjoy, even in smaller doses.

Creating more contact with our taste buds

Nestlé’s approach has been to make what they’re calling “structured sugar.” Using a process that involves spraying sugar, milk and water in warm air, they’re creating porous sugar crystals that dissolve faster than more cubic crystals. This allows more of the key molecules in the sugar to quickly trigger your taste buds, giving you the equivalent experience of eating a sweeter food. By maximizing how much you experience each gram of sugar, Nestle says they’ll be able to cut just how much sugar goes into their recipes by as much as 30 percent, starting with their new Milkybar Wowsomes in the United Kingdom.

DouxMatok’s patented sugar operates on a similar principle. Instead of increasing your tongue’s contact with sugar crystals by making them hollow and porous, their process increases the available surface area of sugar crystals by attaching them to a carrier agent that will help them come in contact with the correct tongue cells. Again, this allows for your tongue to come in contact with more of each gram of sugar, allowing less to be used in a recipe overall.

Selling the public on smaller sizes

Even if both high-surface area sugars keep treats sweet, candy makers are concerned with the dimensions of their product on a larger scale as well. Going back to our original piece of milk chocolate, a 30 percent reduction in sugar will likely result in a noticeable decrease in the candy’s net weight. There’s concern that this may look bad to consumers, and that some new filler agent will be needed to make up the difference.

One option may be just to reshape the chocolate itself. When people were asked to let chocolate pieces melt in their mouths, manufacturers found that spheres were considered the tastiest shape. It’s suspected that a round shape allows air to circulate through the mouth, which makes it easier to smell the compounds that help give chocolate its flavor (aside from all that sugar, of course.)

Source: Designer sugar is here – but just what are we sacrificing for healthier sweets? by Jodi Helmer, The Guardian

On March 25th, 2018 we learned about

Biologists rely on dogs’ sense of smell to find samples of endangered animals’ feces

Dogs’ sense of smell is legendary, possibly on par with their revolting interest in other animal’s poop. Biologists have realized that these two strengths are quite complimentary, and are using dogs to help track down other animals’ scat. It’s an efficient system, and none of the dogs seem to be too disappointed that they aren’t allowed to eat any of the feces that they help find. Instead, the stinky samples are collected an analyzed to assess the health of whichever animal made them. As dogs would surely tell us, there’s a lot of information in poop if you know what you’re sniffing for.

There are currently 17 dogs working for the CK-9 program at the University of Washington Center for Conservation Biology, all of whom have trained to turn their nose into a focused, feces-finding instrument of science. They start on controlled course, where they can be rewarded for finding and reporting poop from specific species, such as spotted owls or caribou. Over time, a dog may train on as many as 13 different species, helping biologists gather data on the state of threatened or endangered animals in need of protection. By analyzing found poop, researchers can figure out an individual’s identity, stress levels and more, all without needing to actually capture any of them.

Sniffing scat on the high seas

Most of this work is conducted on land, but some dogs even work on boats to find whale droppings. Or floatings? Whale poop is often brightly colored and floats on the water’s surface when first released, making it practical to sample if it can be found quickly enough. While a human nose is capable of detecting whale poop, a dog can pick the scent up from a mile away, giving their handler signals about which way the boat needs to go. It has enabled biologists to successfully patrol 100 square miles of territory, keeping tabs on individual whales each year. For example, researchers are currently tracking the levels of toxins from orcas eating Chinook salmon, as it may be influencing whale birthrates around the Pacific Northwest.

Finding feces to play fetch

As much as your dog may be interested in sniffing stool that they find on their evening walk, the C-K9 dogs do still need motivation to stay focused on their task. Instead of food, each successful sample is rewarded with a bit of playtime with a rubber ball. Even on a boat, a short round of fetch is used to keep these dogs going. That may not be a huge motivation for every dog out there, so an intense desire to play fetch is actually the key perquisite to join the C-K9 team. Once properly motivated, it seems that any pooch is capable of finding particular bits of poop.

Source: Meet the Dogs Sniffing Out Whale Poop for Science by Michelle Z. Donahue, Smithsonian

On March 18th, 2018 we learned about

Platypus milk fights bacteria with specially-folded proteins

When you’re as weird a mammal as a platypus, some compromises are to be expected. As monotremes, platypuses hatch their kids out of eggs instead of giving live birth, although mammals don’t really have a monopoly on that bit of child-rearing in the first place. Platypuses do try to stick with the signature mammalian ability to feed milk to their offspring, even if they lack the lips or nipples to make feeding time a tidy process. This kind of milk secretion has required its own set of adaptations, and one of them may prove to be very helpful to humans, regardless of how we nurse.

When a platypus feeds her young, it does so by secreting the milk through special patches of skin around her belly. That milk dribbles into grooves in the mother’s skin where it can be more easily lapped up, or saturate her fur where babies can suckle. The potential complications in this path means that the milk needs extra protection from bacteria who might hitch a ride into the baby’s mouth, and researchers now believe they’ve gotten a handle on the protein responsible.

The protein itself isn’t as exciting as the way it functions. Researchers from Australia’s Commonwealth Scientific and Industrial Research Organization (CSIRO) isolated the protein, then rebuilt it in the lab to more closely observe how it worked. The way the protein folds into a series of curly loops that not only helps fend off bacteria, but also earned it the nickname “Shirley Temple,” after the actress’ hair. If researchers can replicate those properties in other proteins, we can incorporate them into medicines without needing to specifically suck on monotreme stomach hair.

Antibiotics in other mammals’ milk

As special as these proteins are, platypuses aren’t the first mammal to load their milk with bacteria-fighting ingredients. Human milk can also fend off bacteria like Group B. Streptococcus, although we do it with sugars instead of proteins. Those sugars don’t seem to be produced equally by every mom, so researchers are now trying to figure out exactly how they work so their antibiotic properties can be added to more accessible media.

Source: Saving lives with platypus milk by CSIRO, Phys.org

On March 4th, 2018 we learned about

Resilient bacteria in Chilean desert raise hopes of finding microbes on Mars

Life as we know it needs water. Aside from the larger-scale functions we need water for, even bacteria struggle if their proteins unravel when no water is available. So when researchers in the found traces of bacteria and algae in the hyperarid Atacama Desert, it was assumed that these organisms were essentially unlucky. A place that can go years between rainfalls just can’t support life, and so these microbes and accompanying bits of DNA that turned up in soil samples were thought to have been blown in by the wind, and left to decompose among the rocks.

Dormant, but not dead

As it turned out, many of these parched organisms were just waiting for the rain. Soil samples were collected shortly after a rainfall in 2015, and found to be much more biologically active than anyone expected. Researchers were able to see that the microbes were healthy and reproducing, and had apparently only been dormant in the previous dry spell. It’s not an unprecedented survival strategy, as other organisms, such as tardigrades, are also known to become dormant in response to dehydration. However, the idea that these desert microbes essentially spend most of their existence waiting for the next drop of moisture shows that life is worth looking for in even the most extreme environments.

Red Planet proxy

The reason anyone was looking in Atacama in the first place is thanks to its resemblance to another extreme environment that may also be home to dormant organisms. The minimal rainfall and rocky terrain has made the Chilean desert a proxy for the surface of Mars here on Earth. Sure, there’s a lot more oxygen, not as much radiation from the Sun, etc. in Chile, but it’s the closest approximation of our neighboring planet available. As such, it’s been used to test equipment bound for Mars, and in this case, see if there was any hope of finding living things in hyperarid conditions. After all, if nothing could survive in Atacama, the colder and even drier Martian landscape would be an impossible place for any organism to survive.

Instead, it looks like there’s a definite chance that the harsh conditions of Mars could be home to at least dormant microbes. The Red Planet was once wetter and warmer than it is today, and thus more likely to be home to at least microbial organisms like bacteria. As the planet lost much of its atmosphere and grew colder and drier, some of those microbes could have adopted a similar strategy to what was found in Atacama— going dormant until the next round of moisture arrives. Instead of rain, that would most likely be some kind of frost or snow, or possibly just some sub-surface run-off soaking through the Martian soil. It’s no guarantee that we’ll find any native Martian species, but it supports the idea that it’s still worth looking.

Temporarily full of flowers

Funnily enough, the rains can sometimes bring even more than microbes in Atacama. Unusual rainfall in the fall of 2017 actually spurred the growth of flowers and various plants. While it was a lovely sight for tourists, it wasn’t exactly what Mars researchers would want for their investigations.

Source: Life in world's driest desert seen as sign of potential life on Mars by Washington State University, Phys.org