Neuroscientists are known for doing some strange things to mice in their pursuit of learning about the brain. One such strange thing is training mice to self-administer cocaine, but it’s all for a good cause: Self-administration can help us understand the biological underpinnings of substance use disorders.
In a study recently published in Neuron, researchers found that cocaine use changes the DNA in mouse brains, specifically in the brain regions associated with reward. After consuming cocaine, the DNA in their brain cells had different chemical modifications known as epigenetic changes. These epigenetic changes also altered the types of RNAs the cells made through splicing. In this process, pieces of genes are left out or added in to create different RNAs that create different proteins.
Scientists have known RNA splicing is particularly important for neurons, and the researchers behind this mouse study saw many epigenetic and splicing changes after the mice consumed cocaine. Then, they artificially recreated one specific epigenetic change at a gene called Srsf11. This led Srsf11 to be spliced differently. However, Srsf11 is also a gene that controls splicing across the genome, meaning that changes to it had ripple effects in the mice. This one change also altered splicing across a few hundred other genes, some of which were previously implicated in substance use disorders. Most interestingly, the mice with the modified version of Srsf11 self-administered more cocaine, showing that these sorts of changes in the brain may underlie addiction.
Some researchers argue that increasing the body of evidence for the biological basis of substance use disorders reduces stigma against people who use substances, though the effectiveness of this in public messaging is debated. Regardless, though we continue to see evidence that substance use disorders are biologically-driven, there are currently no approved drugs to treat the overuse of cocaine. Epigenetics and RNA splicing may be promising targets for future medical interventions.
When we take medications, we generally do two things: first, we swallow some pills, then we wait for them to kick in. Whether or not they do, however, may be tied to our gut microbes.
Intestinal bacteria influence the availability and activity of therapeutic drugs in the body. For instance, some bacteria metabolically convert, or ‘biotransform,’ drugs into their active forms; others inactivate them. And some, according to a new report published in Nature, don’t chemically manipulate drug molecules — they hoard them.
In this study, researchers incubated 25 representative strains of gut bacteria with 12 orally administered drugs, including those used to treat asthma, high cholesterol, and diarrhea. By measuring drug levels in the growth medium before and after 48 hours of incubation, the scientists identified 29 novel bacteria-drug pairs in which the drug was depleted from the medium. Comparing drug concentrations in the medium alone with that of the total culture revealed that, in most cases, the drug was absent from the medium but recoverable from the total culture. These results suggest the medications were accumulating inside the bacteria.
The question is: When bacteria vacuum up drug molecules, does this alter the drug’s effect on the host?
To explore this, the researchers incubated Caenorhabditis elegans, a nematode and model organism, with duloxetine, an antidepressant that was accumulated by several bacterial strains. While duloxetine alone decreased nematode motility, adding a duloxetine-accumulating strain of E. coli to the culture reduced this effect.
These findings indicate that bacterial hoarding of medications may affect the way those drugs affect their targets. Ultimately, more research is required to determine whether a similar scenario plays out in the human gut, and in the context of other drugs. Greater insight into the interplay between medications and gut microbes could expand our understanding of drug bioavailability and efficacy, and how they may vary from one person (and gut microbiome) to the next.
Fluorescence is caused by an animal absorbing light and bouncing it back out again, and in nature, it’s not a new thing. Fluorescence occurs across only a handful of mammals but they span three different continents and inhabit entirely different ecosystems. The platypus is one such animal, whose glow-in-the-dark abilities were only discovered in 2020.
But, a discovery earlier this year by Northland College researchers that springhares fluoresce is special: it is the first documented case of biofluorescence in an Afro-Eurasian placental mammal. The study purports that perhaps fluorescence in mammals is not as rare as once previously thought.
The researchers entered Chicago’s Field Museum of Natural History armed with a flashlight, with the goal of examining the fluorescent abilities of flying squirrels. Along the way, they accidentally discovered that springhares also glow. One specimen they examined was collected in 1905, and continued to glow in the dark for over 100 years.
The researchers subsequently tested live springhares (this time, in the dead of night—springhares are nocturnal) and found they could also fluoresce, predictably stronger than in the dead specimens. This study raises the questions: What other animals are out there, pulsating in every different shade of the rainbow after the clock strikes midnight?
In a strange triumph of science, researchers have now successfully potty trained 11 cows. The study, done by research groups in Germany and New Zealand, included 16 calves, which they trained by giving the calves a reward when they urinated in a latrine and later by adding an unpleasant stimulus (three-second water spray) when they began urinating outside of the designated area. The calves' potty training performances are equivalent to those of children and better than very young children.
But why is this important?
First, because cattle waste is a substantial contributor to greenhouse gas emissions and soil and water contamination. Being able to collect cow waste in one place would enable us to treat and dispose of it properly. One way of doing it is by keeping the animals confined in barns, but that lowers their welfare conditions.
Second, it shows that cows are able to react to and control their reflexes, indicating that their behavior — like shown with many other animal species before — is subject to modification by using rewards. This demonstrates that cows have more awareness than previously thought, which is important to better understand their wellbeing and welfare needs. Having cattle keep their own living areas a bit cleaner would also increase their welfare.
Potty training cows in farm settings is time consuming and logistically challenging, but it would help significantly decrease gas emissions without compromising animal welfare. Model calculations predict that capturing 80 percent of cattle waste could lead to a 56 percent reduction in ammonia emissions, which would lead to cleaner air for all of us.
Our cells require proteins, which are composed of individual amino acids connected in a long chain, to perform important functions. These amino acids are delivered to protein-building machinery by another molecule called a tRNA. Amino acids and tRNAs are attached together, or charged, by an enzyme colloquially known as ARS.
Mutations in ARS enzymes cause diseases such as Charcot-Marie-Tooth disease, which affects the nerves to a person's arms and legs, because cells cannot make proteins properly. Currently, there are few treatments for ARS defects. However, researchers predict that flooding cells with extra amino acid might allow defective ARS enzymes to function better.
To test this, scientists identified patients with ARS mutations that cause charging defects, and grew their cells in a petri dish. They then treated these cells with different amounts of amino acid, and compared the electrical impedance of the cells that received treatment to those that did not. “Impedance analysis” is an approach where scientists put cells on a surface that can conduct electricity. As cells grow, they block the electrical current, and the speed at which the current is blocked corresponds to how fast the cells are growing.
The scientists found cells with ARS mutations that were treated with amino acids grew faster than cells that did not receive treatment. These promising results meant that the researchers could move on to trying this treatment in the patients themselves. They designed specific amino acid treatments for four people with the same ARS mutations they studied in cells, monitored their symptoms over time, and found that giving patients amino acids alleviated many of their most severe symptoms.
While we still don’t know if these results are applicable to all patients with ARS mutations, this study found a potential new way to treat ARS mutations in patients. Considering that ARS mutations can cause very severe disease, this is exciting and promising for both scientists and patients alike.
Scientists have been predicted that climate change will both increase and decrease the prevalence of a pathogen across its geographic range, depending on local climate effects, a pathogen’s favored conditions, and host factors. In an article published in Nature Communications, a group of researchers led by Joan Dudney demonstrate exactly this in a natural system.
The researchers report the effects of climate change on the occurrence of white pine blister rust in the Sequoia and Kings Canyon National Parks (SEKI) in California. Blister rust is a fungal disease that threatens white pine forests across Europe and North America. Leveraging blister rust prevalence data from two surveys conducted twenty years apart (1996 and 2016) in SEKI, alongside climate data over the same timeframe, they authors found that a warming, increasingly dry climate caused contraction of blister rust's range at low elevations and expansion at higher elevations, where conditions remained relatively mild. They noted an approximately 33 percent decline in overall disease prevalence despite these expansions and high elevations.
The blister rust fungus has a complex lifecycle that requires both a white pine tree and an alternative host, such as Ribes shrubs. Dudney and her fellow researchers found that alternative hosts were less common at higher elevations, likely limiting blister rust's ability to infect pine trees at those elevations even though the pathogen could live there. They also observed that aridity, or dryness, played an important role in determining infection risk.
The study provides a roadmap for future studies on host-pathogen-climate interactions. Genomic adaptations of rapidly reproducing pathogens to changing conditions could further alter these dynamics and represent an additional avenue to explore in future work.
To some animals, their own excretion isn't just waste. They may use their fecal matter to ward off predators. Here are several examples of fecal prowess.
Sperm whales are some of the largest animals to ever exist, reaching a whopping 14 meters long in adulthood. Despite their intimidating size, they still can get spooked (such as by pesky divers) and unleash a poopy trick. Through emergency defecation, a sperm whale can disperse a smoke screen of shit into the water before the cetacean makes its escape. Waving its tail to disperse their poop creates an underwater "poopnado," as Canadian diver Keri Wilk called it. These enormous diarrhea clouds also help recycle nutrients and store immense amounts of carbon, mitigating some effects of climate change.
The larvae of the tortoise beetle are the Captain America of the animal kingdom — because they make shields out of poop. Using their maneuverable anus that sits on their flexible rear end, they deposit their dung defense on their back. The fecal armor, made in part from the larvae's shed exoskeleton, can double as a club to whack off potential predators.
The Green Woodhoopoe takes a rather straightforward approach to defense. Young birds will simply coat themselves in liquid poop, using the odor to deter — or gross out — would-be predators. You wouldn't want to eat a poop-slathered bird now, would you?
Hubble / NASA, ESA, and the Hubble SM4 ERO Team
From our perspective on Earth, most stars look like tiny, twinkling dots. But what color would a star be if you could actually see it up close?
Most astronomy textbooks will clearly say hot stars are blue, and colder stars are red. These colors come from an idealized version of the light a star gives off, called a blackbody curve. That’s not quite the whole story though, especially for smaller stars — the outer layers of a star absorb parts of the light emitted from the center, and our eyes respond differently to different wavelengths of light.
New research published in Research Notes of the American Astronomical Society calculated colors of stars based on their actual energy distributions and the response of the human eye. Turns out, we’ve been missing stars’ true colors. The hottest stars appear blue, as we’ve thought, but stars like our Sun appear off-white. Smaller stars, like K and M stars, are beige instead of red.
Most shocking of all — brown dwarfs aren’t even brown, they’re violet! These cool sub-stars are purple because absorption by molecules in their atmospheres takes out a whole chunk of their visible light, leaving only red and blue light for us to see.
There are a few more complexities that could change the color a star appears to us. For example, clouds on brown dwarfs may change how their atmosphere absorbs light, and that’s something researchers are still trying to figure out. Earth’s atmosphere reddens light, too, so all these colors would look different if we were looking from Earth’s surface. For now, though, it’s fun to have a better idea of what vivid colors are out in the universe, including purple (brown) dwarfs!
Whether you’re a social butterfly or a lone wolf, the brain circuits that define social behaviors begin forming early in life and mature over a lifetime. But how the social brain develops has remained unclear, and new research explores oxytocin – often referred to as the “love hormone” – for answers.
Oxytocin earns its loving nickname because the brain releases the hormone during moments of social bonding, such as those between a parent and child or romantic partners. But beyond this role, oxytocin has long been thought to play a more direct role in social circuit development, and a recent study published in the Journal of Neuroscience put this idea to the test with zebrafish.
Zebrafish are social creatures with evolutionarily similar brain circuitry to humans. Scientists can genetically alter them before observing their behavior across an entire lifespan, making them ideal for studying social behavior. So to understand the role of oxytocin-producing neurons in social brain development, researchers selectively removed those neurons from their brain circuits early in life and examined the consequences to social behavior once the zebrafish reached adulthood.
The researchers evaluated the zebrafish behavior by first separating a fish from a larger group with a transparent barrier, then observing how the lone fish reacts to its isolation. Like a person with FOMO ("fear of missing out") from a party next door, socially healthy zebrafish stay close to the transparent barrier – seemingly longing to join the group on the other side. However, zebrafish with a disrupted social circuit explore their own tank with no preference to socialize.
Researchers found that zebrafish with their oxytocin neurons removed early in life showed less preference to socialize as adults. However, eliminating these cells in adulthood did not affect social behavior, suggesting that oxytocin shapes the social circuit early in life during a critical developmental window. They also found that removing oxytocin neurons early impaired other social brain components, including those required for attention, decision making, and reward.
Together, this suggests that the famous "love hormone" may define our long-term social preferences early in life. But unlike a Pixar movie, fish are not humans, and there is still more to learn about social brain development.
Tool making is a complex behavior that, until recently, had only been confirmed in three species of primates (including humans), and in some birds, including captive Goffin's cockatoos. Now, a research group at the University of Vienna that has studied Goffin's cockatoos for decades has also observed the behavior in wild cockatoos.
This species of cockatoo, a member of the parrot family, is comparable to three-year-old humans in terms of intelligence. But before now, tool making behavior has not been observed in wild cockatoos, which is necessary to confirm that a species is indeed capable of making tools and their tool use is not just an artifact of captivity.
The group spent over 884 hours observing wild birds in their natural habitat in the Tanimbar Islands, Indonesia, with no success in witnessing tool use and manufacture. They then moved on to a catch and release method, where they captured 15 individuals and placed them in temporary aviaries with many resources and a food option that finally encouraged more complex approaches to foraging: the Wawai fruit, or sea mango. The cockatoos really like eating the seeds of these fruits and need to go through the thick skin and flesh of the fruit in order to reach the seeds.
Two of the 15 individuals manufactured and used tools to extract sea mango seeds. Those two birds made tools by removing fragments from branches and then modifying them with their beaks. The researchers identified three different tool types: wedges, to widen the fissures to reach the seed inside the fruit; fine tools used for piercing the coating of the seed; and medium tools used for scooping the seeds. Furthermore, the tools were used sequentially, which the researchers believe to be the most complex example of tool use in a species without hands.
Both cockatoos proficiently manufactured and used the tools immediately after provided the Wawai fruit, suggesting they knew how to do that before capture. The fact that only two individuals were observed using tools indicates that this complex skill is not found species-wide and therefore has to be learned as a result of opportunity and innovation. This finding broadens our understanding of tool making ability beyond just primates.
The growth of modern giant clams is supercharged compared to growth measured from fossil clams. A recent study from the Red Sea has shown this, finding that growth lines from modern species are larger than those of fossils from similar animals dated to the Holocene and Pleistocene.
These increased growth rates appear to be related to higher amounts of nitrate aerosols in the modern atmosphere. These come from many different sources. Some are natural, such as lightning, biomass burning, and soil processing, but most are from anthropogenic activity like burning fossil fuels and agricultural fertilization.
This fast growth may seem like a good thing, but growth doesn't mean anything about the overall health of the clams. Additionally, aerosols may actually reduce the productivity of marine phytoplankton, which represent almost half of the world's primary production.
The overall effects of nitrate and other aerosol pollution on global land and ocean cycles are not well understood. They may appear to reduce global warming by improving carbon dioxide uptake and reflecting the sun's heat, but they contribute to poor air quality. We can congratulate today's super clams on their impressive growth. But in the long run, fewer emissions on our part are probably better for them.
One thousand years ago, archers rode horses across the landscape of Hungary. They were probably intimidating, possibly threatening, and definitely adventurous, but just like equestrians today, they also fell a lot.
These horse riders remain a mystery. Who were they? Where were they from? When did they start riding horses? To answer these questions, an international team of scientists set out to find a way to identify horse riders from just their skeletons, using the fact that horse riders tend to fall.
The researchers examined skeletons from a cemetery of well-known horse riders in Hungary dating to the 10th century CE. Riders in the cemetery were identified by horse riding equipment and horse bones in their graves. However, scientists could not be sure that skeletons without artifacts in the Hungarian cemetery never rode horses. Therefore, they also investigated skeletons from another group of people from 20th century Portugal that definitely did not ride horses.
They found that upper body fractures were more common among riders, and that fractures of the clavicle (collar bone) were significantly more common among the Hungarian riders than the 20th century non-riders. To figure out if these fractures could be caused by horse riding, researchers turned to modern equestrians. Sure enough, fractures of the upper body, especially the clavicle, are some of the most commonly reported injuries in modern day equestrians.
The researchers argue that, in combination with other skeletal changes, clavicle fractures can be used to identify horse riders from just their skeletons. Being able to identify horse riders in the past could help researchers find the first horse riders, shedding light on the ways horse riding shaped human history.
Humans aren't the only animals that step up to help others out of difficult situations. In a study recently published in the journal Scientific Reports, Michaela Masilkova of the Czech University of Life Sciences and her colleagues described a boar's daring rescue of two young wild boars stuck in a trap.
Few animals show this kind of rescue behavior: to go out of their way to help other members of their species that are caught in a dangerous situation. Masilkova's team inadvertently caught an astonishing act of altruism on camera while conducting a separate experiment to monitor wild boar movement for the prevention of African Swine Fever. The goal was to catch boars so the researchers could mark them individually. The researchers set up traps containing food as lure. Once lured inside, a boar would be caged in by logs that would roll off the top of the enclosure and bar the door shut.
One night the trap — operating as usual — snared two young boars. But the night took an unexpected turn when a new herd arrived at the scene. One adult female took particular interest in the captives' predicament. Over the course of 29 minutes, the female pushed against the logs and successfully moved it, allowing the young boars to escape. Given that the rescuer spent so much time on this activity and showed physical signs of distress throughout, the researchers believed her act to be potential evidence of pro-social empathy.
This discovery suggests that complex forms of empathy may just be more common in the animal kingdom than scientists may have previously believed.
In many species, not long after fertilization, the embryo implants into the uterus wall, preparing it for further development. In humans this implantation occurs at around day eight to nine after conception. However, in European roe deer, instead of implanting, the embryo stops developing, hovering in a period of dormancy.
This phenomenon has now been found in over 130 species, including mice and armadillos. But the roe deer have one of the longest known periods of embryonic suspension, lasting up to five months. This period is called diapause. Unlike in many of the other species that can induce diapause, cell division in roe deer embryos do not stop completely, but drastically slows, with cells dividing just once every few weeks.
Until now, the cellular mechanism that regulated the process of extensively slowing down cell replication was unknown. However, a recently published study in PNAS has uncovered it. Researchers discovered that a predominant driver of embryonic diapause is the changing abundance of amino acids in the embryo. One family of amino acids in particular were found to cause a significant increase in a protein called mTORC1, inducing the embryo to activate more of it. In fact, the increase of mTORC1 appeared to immediately coincide with the embryo’s exit from diapause, after which cells start dividing more rapidly, but was not detectable during the previous period of slow cell replication.
The mTOR protein family has been known for many years to be a crucial factor in regulating metabolic pathways, including in humans. In fact, a related protein called mTORC2 thought to be essential for maintaining slow cell divisions remains switched on throughout roe deer diapause. This new study will open up avenues of research into the precise timing of embryo implantation, as well as increasing our understanding about the interplay between the chemical and metabolic pathways of an animal and its embryo.
If you've ever witnessed an overly aggressive guy get bounced from a bar, you probably found yourself internally judging him. But new research published in the journal Animal Behaviour suggests that the opposite may be true for spiders: the more aggressive a male jumping spider is, the sexier his female counterparts find him.
Researchers from the National University of Singapore quantified female spiders' preferences for aggressive males. They first placed males in a small chamber containing a mirror and observed how combative they were toward their own reflection. Once males had demonstrated either their contempt for or passivity towards their own reflections, they were paired with another male for a series of bouts. Using the results from the mirror test and combat trials, the researchers assigned each individual male spider an aggression predictability score. Finally, a pair of one highly aggressive male and one more passive male were placed in a chamber with a single female spider. Female preference was determined based on the amount of time she spent ogling each of her potential suitors.
The researchers found that aggressive males are both more likely to defeat a rival in a combat trial, and to draw a higher amount of attention from females than their more pacifist competitors. They concluded that, not only is this evidence for sexual selection, but that the combination of strong competitiveness and female favor reinforce each other to push the most aggressive spiders to the top of the pile.
People with sickle cell disease encounter significant health issues such as kidney failure. Sickle cell disease, found predominantly in Black and African American populations, is when red blood cells are shaped like crescent moons (or “sickle-shaped”) instead of round and disc-like. This shape, which may have had evolutionary benefits during previous generations, can block blood flow, and therefore oxygen transport, through a person's body.
Kidney failure is a major health complication encountered by people with sickle cell disease. Therefore, people with sickle cell disease are often reliant on dialysis treatment to filter the waste from their blood, but this is often not enough to save their lives.
Therefore, researchers are exploring kidney transplantation as an additional treatment option for patients. In a study published in the Clinical Journal of the American Society of Nephrology, researchers used two national databases that collected information on adults from 1998-2017 with kidney failure who were on dialysis or the kidney transplant list. The researchers measured the impact of kidney transplantation on mortality, as well as differences in access to kidney transplants between people with and without sickle cell disease.
People with sickle cell disease who were on dialysis had a higher mortality risk than the control group. However, the researchers found that transplantation reduced mortality risk for people with sickle cell disease as well as those without it, a benefit that lasted for at least ten years.
Finally, the researchers found that patients with sickle cell were less likely to receive a transplant when compared to the control group, even though kidney transplantation has a higher likelihood of increasing the lifespan of sickle cell patients than does dialysis. This is yet another example of health inequity for Black and African American populations, and one with serious consequences, since kidney transplant is a life-saving intervention for people with sickle cell disease.
Bacteria survive and thrive even in the harshest environments. Scientists have characterized species thriving in Antarctica, and even in deep-sea oil wells. Now, a study published in PNAS in August found that many bacteria can live without food for more than 1000 days.
Using 100 different types of bacteria, researchers tracked their growth and survival over time. This allowed them to model how long the community could eventually live. Early on, many of the bacteria within a population died out. But the remaining bacteria ate these dead cells. Afterward, the rate of bacterial death slowed as they adapted to low-energy conditions. Over these 1000 days, natural selection drove innovative survival strategies.
The study shows that many bacterial species can survive far harsher conditions than scientists would have predicted. Their persistence could allow them to survive thousands of years. It is also important for learning why certain recurrent infections are difficult to cure, and provides more credence for researchers focused on findings signs of microbial life on Mars. After all, if most microbes can survive without any food, they might be able to persist in even harsher environments on other worlds.
are found in marine and aquatic environments worldwide because they are used in personal care products, and result from the breakdown of larger plastic waste. Many researchers, policy makers, and scientists in the the private sector are concerned about how microplastics affect the environment, ecologically and commercially important species, and human health.
The effects of microplastics on freshwater species are less well-studied than those in marine species. In a study published in Environmental Toxicology, researchers from tested zebra mussels found in a German lake for various signs of microplastic toxicity and connections between toxicity and physical traits. Zebra mussels are a freshwater mollusk native to Russia and Ukraine, that are now considered an invasive species in Europe and North America. The researchers also repeated some tests with duck mussels and Chinese pond mussels to compare the results.
All three freshwater mussel species showed little impact from microplastics. For zebra mussels in particular, microplastic toxicity only affected their ability to filter algae for food. The researchers believe this happens as a result of their ability to filter out microplastic particles before ingesting them. Given the harsher impacts of microplastics on other animals, the team may study how the filtering is so effective in comparison to other shellfish, for instance.
Fat, oil, and lard. The purported nutritional value of each has changed over the past decade, and while health experts now assert that not all fat is bad for you, it can be challenging for the everyday person to figure out which one to eat.
Oil from soybeans is the most widely consumed oil in America. However, its effects on the gut microbiome are poorly understood. Studying this oil and how it interacts with gut bacteria can help us to understand the its impacts on our health.
A study published recently in the Journal of Nutritional Biochemistry looked at how soybean oil interacts with mouse microbiomes, as a model for how it affects human microbiomes. Soybean oil is rich in health-promoting omega-6 fatty acids, which are broken down into smaller molecules called sphingolipids and ceramides. In healthy mice, increased levels of ceramides found in the liver have been shown to result in insulin resistance while those found in the blood are associated with cardiovascular disease.
To model human diets, standard lab mice and mice devoid of all microorganisms (germ-free mice) were fed either low fat diets or diets supplemented with soybean oil for 10 weeks. The researchers measured fatty acid and sphingolipid levels in their blood and livers, and analyzed microbial DNA from their feces to determine the amount of gut bacteria present.
One group of germ-free mice was found to be contaminated with bacteria at low levels due to difficulties in sterilizing the diet. This group led the researchers to find that large amounts of gut bacteria present may increase the amount of ceramides in the liver regardless of how little or excess fat is consumed. High soybean oil levels made the mice gain fat, but those with colonized microbiomes were able to accumulate more fat than the germ-free mice. Therefore, they concluded that sphingolipids in the liver are more affected by our gut microbiomes than the amount of fat in our diets.
This study suggests that soybean oil consumption in Western diets should be moderated with future interest in finding alternative sources of omega-6 fatty acids.
Want to make a new planet? All you need is a newborn star and a metric boatload of gas and dust particles. As they orbit the young star, these tiny bits of ice and dust collide, eventually growing up into full-blown planets.
Seems simple enough. But what about making a planet with two suns? Stars are generally much bigger than planets, and throwing a second one into the mix — as in a binary system — speeds up how fast the pre-planet space dust swirls around thanks to increased gravitational forces. At those speeds, collisions mean destruction and it’s hard to build a planet. But scientists have detected exoplanets orbiting around binary star systems. So how did they get there?
A solves this mystery by simulating the planet formation process in a specific type of binary star system, where the smaller star orbits around the larger star about once a century. The researchers found that, as long as the bits of dust and ice swirl around the main star in a roughly circular orbit, any drag effects from stellar gas become very large in certain parts of the disc. This drag slows down the dust particles to more reasonable, less explosion-y speeds so that they can actually stick together instead of destroying each other. The leading particles in a group are slowed more than the ones behind it, allowing the trailing particles to catch up and join the expanding clump. It's like a cycling road race. Cyclists tend to race in packs because wind drag is reduced behind a teammate. Once larger boulders about 10 kilometer in diameter are formed, they can survive high-speed collisions and are able to grow normally up to planet sizes.
While this particular kind of binary star system is now better understood, the next mystery for the new model to tackle is the formation of "Tatooine"-style planets, which orbit both stars in a binary system instead of just one. NASA’s Kepler Space Telescope has already found some of these deep in space, but we still don’t quite understand how they’re made.
Seiya Ishibashi / Wikimedia
Slime mold, Physarum polycephalum, is famous for its seeming intelligence in and . Sometimes called The Blob, this unicellular network of tubes grows in intricate designs that slowly pulsate and crawl across rotting logs. They eat dead plants and will reconfigure their structures to approach food — enlarging their tendrils toward snacks. Researchers have described this behavior, where a slime mold repeatedly positions near a food source, to reflect formed memory. A pair of scientists, Mirna Kramar and Karen Alim, wanted to . Kramar and Alim's results appeared in PNAS in March.
Previous explanations, such as mechanisms involving and altering , would require at least 30 minutes to establish a non-neuronal memory — too long to fit slime mold learning observations. The researchers made mathematical models to explain how slime mold changes its shape, and they found that food triggers a progressive change in tendril diameter that is slower than the speed of pressure propagation but faster than speed of diffusion. Therefore, perhaps a signal is being transported in the fluids within the tendrils. This signal was proposed to be released when contacting food, increasing tendril diameter while simultaneously shrinking the distant tendrils (because the total fluid volume within all of the tendrils remains constant).
Although Kramar and Alim did not directly test the nature of this signal, they proposed that it is a chemical that softens the tendril structure, such as adenosine triphosphate (ATP). ATP levels have been measured to be double in slime molds at their migration front than the trailing back. Softening tube walls helps the slime mold grow or spread when migrating.
Researchers use “memory” more broadly than in colloquial terms, but are slime molds really exhibiting associative memory, or are they just reacting? The mentioned study suggests that slime mold exhibits encoded memory because their shape persists longer than transient reactions. Its gently initiates a philosophical discussion for distinguishing memory from reactions.
Synapses are the connection points between neurons where information is exchanged through chemical signals. As infants, we have an abundance of these connections, but when we transition into adulthood, the number of synapses in our brains decrease substantially. During this process, called , unnecessary synapses are eliminated in order to strengthen the most important ones. By reducing synapses, the brain refines the circuits that allow us to learn, remember, and function properly throughout our lives.
One of the key players involved in pruning are , the immune cells of the brain. Microglia “nibble” at pieces of synapses, which allows new connections to form as the brain is remodeling during development. Researchers have been investigating how microglia can target specific types of synapses and why microglia nibble some synapses in favor of others.
a subset of microglia that make direct contact with inhibitory synapses. These synapses can be thought of as a brake pedal, and when they release the neurotransmitter , they subdue activity of the cell receiving the signal. Interestingly, microglia make most of these contacts with GABA synapses early in life, during the prime time for synaptic pruning.
The researchers used mice to find out the role of microglia in the development of these connections. They treated newborn mice with a compound that diminishes microglia during the critical window when those microglia would typically be most active in pruning. When the microglia-deficient mice grew up, their brains contained more inhibitory synapses compared to mice that grew up with intact microglia. Genetically altered mice that lacked microglia with GABA receptors were also impacted behaviorally, displaying more hyperactive tendencies.
Microglia are crucial for remodeling synapses in the brain early in life. When microglia functioning is disrupted, it can affect synaptic pruning and lead to behavioral disorders including and . By characterizing different subtypes of microglia and how they interact with neurons, scientists are revealing how synapses become mature and how these processes can go awry.
The causes of the US opioid epidemic are complex, but excessive prescription of opioid painkillers . As a result, health authorities now that doctors gradually reduce or discontinue prescribing opioid painkillers to their patients with chronic pain, a practice referred to as opioid tapering.
The results were recently published in the Journal of the American Medical Association by a team of researchers at the University of California, Davis. To evaluate the potential harm of tapering opioid prescriptions, the researchers looked at the health data of 113, 618 people who were prescribed stable, high-dose opioid therapy for at least a one year period of time from 2008 to 2019. Next, they compared the health outcomes of people whose opioid therapy was tapered to the health outcomes of people before opioid tapering or whose opioid therapy was not tapered. They found that opioid tapering is associated with an elevated risk of both drug overdose and mental health crises, specifically depression, anxiety, and suicide attempts.
The researchers caution that interpretation of their findings is limited by the study’s observational design. Nonetheless, the results raise questions about the risks of opioid tapering, highlighting the importance of to minimize those risks, such as careful planning, monitoring, and coordination between patients and doctors.
Trans and gender-nonconforming people may express themselves in gender-affirming ways, such as choosing clothing, changing their names or pronouns, beginning hormone replacement therapy, and undergoing surgery. “Detransitioning” — reverting to representing oneself as one’s sex assigned at birth — is often incorrectly conflated with regret by the media.
In a study published in LGBT Health, researchers of psychiatry and health policy examined results from the US Transgender Survey, which includes responses from 27,715 transgender and gender diverse adults, and found that very few people detransitioned due to internal regrets. Of 2,242 survey respondents who detransitioned, 82.5 percent did so because of external factors, such as pressure from family, threats of violence, or losing employment or education opportunities. Only 2.4 percent of respondents who reported detransitioning attributed it to doubt about their gender identity.
This result characterizes a relatable, human experience: wanting to be safe and supported by one’s family and community. People who choose to detransition may remain part of the trans community and may later seek gender-affirming care.
For the first time, a type of CRISPR/Cas9 genome editing, called prime editing, has been performed in “mini-organs” to correct the mutation causing cystic fibrosis.
Cystic fibrosis is thought to affect more than 70,000 people worldwide. It is a genetic disease caused by a mutation in a single gene, called the CFTR gene, which result in a dysfunctional CFTR protein. This dysfunctional protein aspect is what causes the main symptom of cystic fibrosis; a sticky mucus buildup in the respiratory tract and lungs.
Published in Life Science Alliance, researchers from the Hubrecht Institute, in collaboration with UMC Utrecht and Oncode Institute, demonstrated that they were able to correct a mutation in CFTR that causes cystic fibrosis by performing genome editing in a mini-organ called an organoid. The organoids, mini intestines, had been grown from stem cells originally collected from patients with cystic fibrosis.
Prime editing is different than traditional CRISPR genome editing. Instead of acting as a pair of scissors, prime editing uses a modified Cas9 protein to make a direct change to the DNA sequence. In doing so, the researchers are able to change the underlying DNA sequence without cutting the DNA. This also reduces the risk of Cas9 cutting randomly elsewhere in the genome.
To test if the prime editing was successful, the researchers, led by Hans Clever, added a treatment called forskolin to the organoids. In healthy organoids, addition of forskolin causes the mini-intestines to swell up due to movement of fluids into the center. The researchers found that this happened in some of the prime edited organoids as well, suggesting that the mutation had been corrected. Organoids that carried a CFTR gene with a mutation however, did not respond to forskolin treatment.
Prime editing efficiency is variable between organoids and cell types, an important consideration in the developments towards gene therapy for cystic fibrosis and other diseases. Moreover, significant research effort should be invested into ensuring that prime editing techniques do not cause any unintended off-target effects. Despite this, these proof-of-principle research findings provide a step forward for the understanding and future developments of gene therapy for cystic fibrosis treatment.