When invasive rats chow down on island seabirds, coral reefs suffer.

Researchers studied islands with and without the rodents in the Chagos Archipelago in the Indian Ocean. On rat-free isles, there were on average 1,243 birds per hectare compared with about two birds per hectare on rat-infested islands, the team found. And these rodentless islands had healthier coral reef ecosystems. The secret: Bird poop, naturally rich in nitrogen, washes into the ocean and helps keep reefs productive, the scientists report in the July 12 Nature.
“We’re essentially linking three ecosystems in this study,” says study coauthor Nick Graham, an ecologist at Lancaster University in England. The rats affect the seabirds, which affect the reefs.

Introduced by humans to the Chagos Archipelago in the late 18th century, rats have since devastated native seabird populations, including red-footed boobies and terns. The rodents will eat seabird eggs, chicks and even the brains of adult birds, says Holly Jones, a restoration ecologist at Northern Illinois University in DeKalb who was not involved in the study. Rats are a major problem, Jones says, because seabirds are “ecosystem engineers.” When they’re gone, the environment on land and in the water changes dramatically.
Bird poop, or guano, is rich in certain heavy nitrogen isotopes — different forms of the element with the same amount of protons but varying numbers of neutrons — which come from the animals’ diet. Graham and his colleagues tested for these isotopes on 12 islands, six with rat infestations and six that had no rats, and in nearby coral reefs.
Compared with rat-infested islands, the team found much more of the heavy nitrogen in the soil of rat-free islands, where bird populations still thrived, and in the algae, sponges and fish in reefs that surrounded those islands. Bird guano is known to leach into the sea in rainwater or lapping waves, but its effects on reefs has been unclear.
The researchers now suspect the reefs around rat-free islands are healthier in part because nitrogen can act as a fertilizer for ocean plants and algae. More algae grow, leading to more fish grazing on the reefs and helping clear out dead corals, essential processes for a healthy reef. The fish that lived near reefs with more nitrogen also grew larger and faster, the scientists showed.

In addition to these indirect effects on reefs, nitrogen may also directly help the corals, says David Gillikin, a biogeochemist at Union College in Schenectady, N.Y., who was not involved in the study. Between 15 and 50 percent of nitrogen found in corals comes directly from seabird guano, he says.
Eradicating invasive rats from the islands will help preserve reefs, Graham says. Rat extermination has been done on 580 islands worldwide, with a success rate of about 85 percent.

Still, many coral reefs have been in trouble for decades and face various threats, including bleaching and ocean acidification, both consequences of climate change (SN: 5/12/18, p. 20). The UNESCO’s World Heritage Centre estimates that large coral reefs could be gone by the end of this century. “We’re constantly looking for solutions for the coral reef crisis,” Graham says.

Protecting seabirds to save coral reefs is one solution that doesn’t stink.

Painkillers crafted with a part of the wrinkle-smoothing drug Botox provide long-term pain relief in mice.

Researchers added the modified Botox to molecules that target pain-messaging nerve cells. Mice given a single spinal injection of the new drugs showed signs of pain relief for the full duration of the experiments, around three weeks, researchers report online July 18 in Science Translational Medicine. Such painkillers could potentially one day be developed for humans as alternatives to more addictive drugs, such as opioids.
Created by the bacterium Clostridium botulinum, botulinum toxin causes the food poisoning disease botulism. Botox, which is made from the toxin, is often injected into people to iron out worry lines and has been used to treat conditions that involve overactive muscles, such as repetitive neck spasms or overactive bladder (SN: 4/5/08, p. 213). The toxin has also been used to reduce the frequency of migraines.

Biochemist Bazbek Davletov of the University of Sheffield in England and colleagues focused on botulinum toxin because it can stop certain nerve cells from communicating with one another for up to five months with each injection. And “you locally inject less than a millionth of a gram, which is helpful to avoid any immune response,” he says.

Davletov and colleagues created their new drugs with a process he describes as a “molecular Lego system.” Taking the part of the botulinum toxin that blocks nerve cells from sending messages, the team attached the piece to one of two molecules that target neurons that relay pain information. The researchers removed the part of the toxin, found in Botox, that binds to muscle-controlling nerve cells.

In the new study, the scientists injected SP-BOT, a botulinum toxin-based pain reliever they’d made previously, into the spinal fluid of male mice with pain due to nerve damage. SP-BOT provided pain relief starting around three days after the injection and lasted through the rest of the experiment. In another experiment, SP-BOT also mollified pain from inflammation due to a different injury.
The researchers also created a new formula, called DERM-BOT, which targets nerve cell opioid receptors with dermorphin, a natural opioid secreted from the skin of a South American tree frog. DERM-BOT injected in mice with nerve damage kicked in right away and then provided pain relief to the rodents for over three weeks. The drug was also likewise effective in lessening pain from injuries that produced inflammation.

The team gauged the painkillers’ effectiveness by poking the animals’ paws with plastic filaments of different diameters. Mice in pain withdrew their paws from the finer filaments, Davletov says, while mice with pain relief didn’t withdraw until prodded by the thicker filaments, the same behavior seen in healthy mice.

Injecting the drugs into healthy mice caused no mobility issues, the researchers found, indicating that the drugs did not target muscle-controlling nerve cells as Botox does.

Neuroscientist Luana Colloca of the University of Maryland, Baltimore, who was not part of the study, says the drugs are promising candidates for further research in humans. Short-term painkillers, including morphine, may require multiple daily doses, and a body can build up tolerance and require higher doses for relief, she says. “One single administration lasting for several months can reduce the risk of dependence and addiction.”

But the drugs should be tested in female animals, Colloca adds. “We truly need to know if this data apply also to women in pain.”

An intergalactic race between light and a bizarre subatomic particle called a neutrino has ended in a draw.

The tie suggests that high-energy neutrinos, which are so lightweight they behave as if they’re massless, adhere to a basic rule of physics: Massless particles travel at the speed of light.

Comparing the arrival times of a neutrino and an associated blaze of high-energy light emitted from a bright, flaring galaxy (SN Online: 7/12/18) showed that the neutrino and light differed in speed by less than a billionth of a percent, physicists report in a paper posted July 13 at arXiv.org.
Massless particles — including the particles of light known as photons — consistently move about 300,000 kilometers per second, while massive particles move more slowly. Although neutrinos have mass, their heft is so infinitesimal that high-energy neutrinos travel at a rate effectively indistinguishable from that of light.

Some theories propose that a “spacetime foam” might slow particles of very high energies. The idea is that spacetime on extremely small scales is not smooth, but foamy. As a result, high-energy particles could get bogged down, as if moving through molasses. That effect could cause a significant difference between the speeds of the neutrino and the associated light, which would build up into a delay over the 4-billion-light-year trip from the neutrino’s home galaxy to Earth. But since the flare of light was spotted around the same time as the neutrino, there’s no evidence for such a discrepancy.

The result once again refutes a 2011 claim that neutrinos might travel faster than light. That measurement, made by a particle detector known as OPERA, was eventually determined to have been distorted by a loose cable (SN: 4/7/12, p. 9).

In the final frenzy of reproduction and death, social amoebas secrete proteins that help preserve a starter kit of food for its offspring.

Dictyostelium discoideum, a type of slime mold in soil, eats bacteria. Some wild forms of this species essentially farm the microbes, passing them along in spore cases that give the next generation of amoebas the beginnings of a fine local patch of prey. Tests find that the trick to keeping the parental immune system from killing this starter crop of bacteria is a surge of proteins called lectins, researchers say in the July 27 Science.
Lectins create a different way for the amoebas to treat bacteria: as actual symbionts inside cells, instead of as prey or infections, says study coauthor Adam Kuspa, a molecular cell biologist at Baylor College of Medicine in Houston. In a lab test of this ability, coating other bacteria with lectin derived from a plant allowed bacteria to slip inside cells from mice and survive as symbiotic residents.

The findings mark another chapter in a story that has been upending decades of what people thought they knew about social amoebas eating bacteria. The basic, almost alien, scenario is still true: D. discoideum amoebas, nicknamed Dicty, start life as single cells. When food dwindles, cells come together into a much bigger, multicellular slug-shaped creature with eight to 10 types of cells and the power to crawl. It then develops into something more like a fungus with a stalk holding up a case of spores, which start the next generation of amoebas.
Those casings, scientists once believed, held only spores. “For 70 years, we all thought that Dictyostelium development was sterile,” meaning no bacteria survived among spores, Kuspa says. “If you were not a very good microbiologist and contaminated your amoeba sample, one way to cure them of bacteria was to put them through a cycle of development.”
Then in 2011, researchers discovered that some Dicty strains are “farmers,” routinely packing live bacteria into spore cases, and jump-starting new bacterial livestock with each generation (SN: 2/12/11, p. 11). “That was a shock,” Kuspa says.

Researchers also discovered that the Dicty animal-like slug phase forms an immune system that kills bacteria, even as evidence grew that some bacteria had uses beyond food, such as providing defense chemistry. But how the slug avoided killing its own helpful bacteria was a mystery.

Comparing secretions of Dicty strains carrying bacteria versus strains that don’t showed a “dead-obvious” difference, Kuspa says: more lectins called discoidin A and discoidin C in the carrier forms. A series of tests supplying and withholding the proteins showed big effects on the fates of bacteria. The researchers found that the lectins raise the chances that bacteria can slip inside an amoeba cell and live hidden from immune-system sentinels that purge free-living intruders. That gives the bacteria a chance to end up in the spore case.

Lectins’ powers help make sense of how the startling discovery of bacterial farming fits with the revelation of social amoebas’ bacteria-killing immune systems. “Outstanding” work, says Debra Brock of Washington University in St. Louis, who studies both phenomena. “I love mechanisms.”

A new species of Ebola virus has been discovered in bats in Sierra Leone, the country’s government announced July 26. Researchers looking to identify new viruses before the pathogens spill over into human populations found the new Ebola strain while sampling bats in the northern Bombali district. This is the sixth known species of the virus.

RNA analysis of the virus revealed that it is “definitely related to other Ebola viruses,” says Tracey Goldstein, a pathologist at University of California, Davis, who is with the virus-hunting PREDICT project. “But [it] was quite different.”
Goldstein and her colleagues confirmed that the Bombali virus can infect human cells, but they still don’t know whether or not it can cause disease in people. “It has the machinery” to enter a human cell, she says, but that doesn’t mean that it can make people sick.

Some species of Ebola, such as the Reston virus, can cause disease in nonhuman primates but do not sicken humans. Other species of the virus however, like the Zaire virus, have been responsible for widespread epidemics, including a recent outbreak in the Democratic Republic of Congo that killed 33 people (SN Online: 5/18/18) and an earlier one responsible for more than 11,000 deaths across West Africa (SN: 1/24/15, p.12).

“We don’t really know where on the spectrum [the Bombali virus] stands,” Goldstein says. PREDICT and its partners are continuing to study the virus, and are educating people in the Bombali region to stay away from bats. At this point, Goldstein says, “I don’t think people should be alarmed.”

For nearly 60 years, scientists in Siberia have bred silver foxes in an attempt to replay how domestication occurred thousands of years ago. Now, in a first, researchers have compiled the genetic instruction book, or genome, of Vulpes vulpes, the red fox species that includes the silver-coated variant. This long-awaited study of the foxes’ DNA may reveal genetic changes that drove domestication of animals such as cats and dogs, the team reports online August 6 in Nature Ecology & Evolution.

At the Institute of Cytology and Genetics of the Russian Academy of Sciences in Novosibirsk, Russia, researchers bred one group of foxes for ever-tamer behavior, while another group was bred for increasing aggressiveness toward humans (SN: 5/13/17, p. 29). Rif, the male silver fox whose DNA serves as the example, or reference, genome for all members of the species, was the son of an aggressive vixen and a tame male.
Geneticist Anna Kukekova of the University of Illinois at Urbana-Champaign and colleagues also conducted less-detailed examinations of 30 foxes’ DNA: 10 foxes each from the tame and aggressive groups and 10 animals from a “conventional” group that hadn’t been bred for either friendliness or aggression.
Those genomes are an invaluable resource for researchers studying domestication, behavioral and population genetics and even human disorders such as autism and mental illness, says Ben Sacks, a canid evolutionary geneticist at the University of California, Davis, School of Veterinary Medicine. “It makes all kinds of research possible that weren’t before,” he says.
Domestication researchers want to pinpoint the genes that set tame foxes apart from conventionally bred and aggressive foxes because those genes may be the same ones that were altered in dogs and other domesticated animals. Kukekova and colleagues haven’t yet identified the precise genetic changes that led to the foxes’ tameness. But the team did find 103 regions of the genome where tame foxes tend to have one pattern of genetic variants and aggressive foxes are more likely to have a different pattern. Some of the regions contain multiple genes and DNA tweaks.
Narrowing the search to precise DNA changes will take more work, but the research is an important first step, says geneticist Elaine Ostrander, chief of the Cancer Genetics and Comparative Genomics Branch at the National Human Genome Research Institute in Bethesda, Md. She likens it to zooming in on a map.

“Before you get to the right house, you have to get to the right street. Before you can get to the right street, you have to get to the right city, state and so on,” she says. “It’s exciting that they’re to the right city at this point. Now they have to find the right addresses.” The list of 103 regions gives researchers clues about where to focus future studies, she says.

Many of the genes in the 103 regions are involved in brain development or function. In particular, the researchers found that a gene called SorCS1 is involved in making friendlier foxes. In people, some versions of the gene have been associated with autism or schizophrenia. Versions of that gene, which encodes a protein involved in transmitting chemical information between brain cells, determined whether foxes wanted to interact with humans “or never wanted to come close or see you again,” Kukekova says. One version of SorCS1 was found in 61 percent of tame foxes, but none of the aggressive foxes.
Other genes that differed between tame and aggressive foxes included ones involved in brain-cell signaling with the chemical messenger glutamate (SN Online: 5/15/13). Changes in these genes have also been associated with domestication in dogs, cats and rabbits.

Finding the same tweaked genes in studies of many different domesticated animals gives researchers confidence that they are closing in on the right answer, says evolutionary geneticist Krishna Veeramah of Stony Brook University in New York. But because of its long history and wealth of data, the fox study is the true test, he says. Having the same genes pop up in silver foxes “is incredibly encouraging that they are the real ones involved in domestication.”

Some lizards shed their still-wriggling tails to distract predators, but sea cucumbers take this sort of strategy to the next level. Some startled sea cucumbers shoot a silky — and sticky — substance out of their rear ends that is actually an entire organ.

The tangle of tubules looks like intestines, but it evolved from the invertebrates’ respiratory system, and, like lizard tails, it regenerates after use. In a new study in the April 10 Proceedings of the National Academy of Sciences, researchers delved into the black sea cucumber’s genome to see how the stringlike tubules, called the Cuvierian organ, work at the molecular level.
The black sea cucumber (Holothuria leucospilota) is “the most dominant sea cucumber species in the South China Sea,” says Ting Chen, a biologist at the South China Sea Institute of Oceanology in Guangzhou. “We would like to know what evolutionary advantage this sea cucumber has gained … so that its population can expand so widely and predominantly.”
So the team analyzed the sea cucumber’s entire genome, or genetic instruction book, and focused on genes from the Cuvierian organ because it’s such an odd structure. Then the team predicted what proteins would be made from Cuvierian organ genes using a program called AlphaFold (SN: 9/23/22). Some unexpected predicted proteins were new types of receptors on cells’ surfaces that may play a role in expelling the organ.

The team also found that the “silk” proteins of sea cucumbers’ tubules don’t contain the same sequences of amino acids seen in spider silk, but are similarly made up of long repeated chains of amino acids. This finding hints that these long repeats might be a shared structure across silklike proteins, even when those proteins evolved independently.

What’s more, Chen says, is that the organ’s stickiness — which stops sea cucumber predators like fish, crabs and starfish in their tracks — comes from proteins that have features similar to amyloids. Amyloids are associated with many diseases in humans, including neurodegenerative conditions like Alzheimer’s (SN: 9/9/15).

This paper not only highlights unexpected proteins that are specific to the Cuvierian tubules, says Patrick Flammang, a biologist at the University of Mons in Belgium who was not involved with the study. It also provides a lot of data that can be used to answer other questions about how the enigmatic organ evolved, he says.

And the usefulness of a high-quality genome doesn’t stop there. “We need genomic data for our studies on the reproductive, endocrine, immune and digestive systems of H. leucospilota,” Chen says. The team, he says, is now investigating the genetics behind how the sea cucumbers detect light and digest food.

A good genome, Flammang says, is “a cornerstone to be able to do this work.”

To understand the human brain, take note of the rare, the strange and the downright spooky. That’s the premise of two new books, Unthinkable by science writer Helen Thomson and The Disordered Mind by neuroscientist Eric R. Kandel.

Both books describe people with minds that don’t work the same way as everyone else’s. These are people who are convinced that they are dead, for instance; people whose mental illnesses lead to incredible art; people whose memories have been stolen by dementia; people who don’t forget anything. By scrutinizing these cases, the stories offer extreme examples of how the brain creates our realities.
In the tradition of the late neurologist Oliver Sacks (SN: 10/14/17, p. 28), Thomson explores the experiences of nine people with unusual minds. She travels around the world to interview her subjects with compassion and curiosity. In England, she meets a man who, following a bathtub electrocution, became convinced that he was dead. (Every so often, he still feels “a little bit dead,” he tells Thomson.) In Los Angeles, she spends time with a 64-year-old man who can remember almost every day of his life in extreme detail. And in a frightening encounter in a hospital in the United Arab Emirates, she interviews a man with schizophrenia who transmogrifies into a growling tiger. By visiting them in their element, Thomson presents these people not as parlor tricks, but as fully rendered human beings.
Kandel chooses the brain disorders themselves as his subjects. He explains the current neuroscientific understanding of autism, depression and schizophrenia, for example, by weaving together the history of the research and human examples. His chapter on dementia and memory is particularly compelling, given his own Nobel Prize–winning role in revealing how brains form memories (SN: 10/14/00, p. 247).

With diagrams of key brain regions, Alzheimer’s plaques and even chromosomes, Kandel’s book reads in some ways as a primer on the basic tenets of biology and neuroscience. Also included are stories of people, such as a woman who describes her bipolar illness in stark terms: “Feelings of ease, intensity, power, well-being, financial omnipotence and euphoria pervade one’s marrow.” But then, she says, everything changes. “You are irritable, angry, frightened, uncontrollable and enmeshed totally in the blackest caves of the mind. You never knew those caves were there. It will never end, for madness carves its own reality.”

Though these cases seem extreme, Thomson and Kandel relate unusual brains to more common forms of thinking. Observing huge emotional swings that come with bipolar disorder can help inform scientists about more mundane changes in our happiness or sorrow. Figuring out why a person thinks he’s dead could reveal how we more generally create our sense of self. Understanding why someone might remember everything, or nothing, could help us understand how memories physically change the brain (SN: 2/3/18, p. 22).

By connecting these strange brains to everyday mental processes, both books make clear how much we all have in common, and more than that, how all our brains are a little bit unusual.

Some snippets of RNA can be a real pain.

A microRNA called miR-30c-5p contributes to nerve pain in rats and people, a new study finds. A different microRNA, miR-711, interacts with a well-known itch-inducing protein to cause itching, a second study concludes. Together, the research highlights the important role that the small pieces of genetic material can play in nerve cell function, and may help researchers understand the causes of chronic nerve pain and itch.
MicroRNAs help regulate gene activity and protein production. The small molecules play a big role in controlling cancer (SN: 8/28/10, p. 18) and other aspects of health and disease (SN: 2/20/16, p. 18). Usually, microRNAs work by pairing up with bigger pieces of RNA called messenger RNAs, or mRNA. Messenger RNAs contain copies of genetic instructions that are read by cellular machinery to build proteins. When microRNAs glom onto the messengers, the mRNA can be degraded or the microRNAs can prevent the protein-building machinery from reading the instructions. Either way, the result is typically to dial down production of certain proteins.

In the case of nerve pain, miR-30c-5p limits production of an important protein called TGF-beta that’s involved in controlling pain, María Hurlé, a pharmacologist at the University of Cantabria in Santander, Spain, and colleagues report August 8 in Science Translational Medicine. The researchers discovered the link in experiments with mice, rats and people.

In the rat experiments, researchers cut the sciatic nerve in the thigh, making the rodents more sensitive to pain caused by heat or cold. These rats had more miR-30c-5p in their blood and cerebral spinal fluid than uninjured rats did, Hurlé and colleagues found. And the amount of the microRNA in the rats’ blood correlated with their pain sensitivity. People with nerve pain caused by a lack of blood flow to a limb also had elevated levels of the microRNA in their blood and spinal fluid.
Hurlé’s group confirmed that the microRNA was causing pain by injecting uninjured rats with miR-30c-5p
or an imposter microRNA. Those rats that got the imposter injected into their brains had normal pain sensitivity, but rodents shot up with miR-30c-5p became sensitive to cold pain. Researchers also blocked miR-30c-5p by using another piece of RNA that would latch onto it and prevent it from interacting with the mRNA for TGF-beta. Pain-sensitive rats that got the blocker RNA recovered normal pain responses. “This was a spectacular result,” Hurlé says.
But the finding doesn’t mean that doctors can treat nerve pain by blocking the microRNA in people, she says. Both the microRNA and TGF-beta do too many other important jobs throughout the body to mess with them. The research, however, does suggest that the level of miR-30c-5p in people’s blood and spinal fluid might be a good indicator of nerve pain.

Having a nerve pain indicator would be useful, says Marzia Malcangio, a neuropharmacologist at King’s College London who was not involved in either study. Pain doctors don’t know of any biological molecules that can distinguish nerve pain from pain caused by inflammation or other causes, Malcangio says. Making that distinction is important because different types of pain are treated differently.

A different microRNA, miR-711, seems to be the culprit causing chronic itching in people with lymphoma, neurobiologist and pain researcher Ru-Rong Ji and colleagues report in the Aug. 8 Neuron.

Cancerous immune cells called T-cells secrete miR-711, the team showed in experiments with mice. And giving mice the microRNA by itself made the rodents scratch. Surprisingly, the researchers found, the microRNA gloms onto a well-known pain and itch sensing protein called TRPA1 outside of a cell, instead of binding to an mRNA inside a cell like other microRNAs.

That finding may be a big advance in understanding how itch works, Malcangio says. Chemicals that trigger TRPA1 from inside a nerve cell open a floodgate that allows calcium to pour in and launch a pain signal. Tickling TRPA1 with the microRNA on the outside of the cell causes just a trickle of calcium into the nerve, producing itch instead of pain, Ji, of Duke University School of Medicine, and colleagues propose.

The team designed a peptide (a small protein or portion of a protein) that could block miR-711 from binding to TRPA1. Itchy mice that got the blocking peptide scratched about half as often as mice that got miR-711 injections alone.

Ji thinks the blocking peptide may be able to reduce itch in lymphoma patients, but the team needs to do more research before giving it to people. About a third of Hodgkin’s lymphoma patients and 15 percent of people with non-Hodgkin’s lymphoma have severe itching. The researchers are also investigating whether the microRNA is involved in other types of itchy conditions, such as eczema.

Landing sites on the asteroid Ryugu for the Hayabusa2 spacecraft and its hitchhiking landers have been picked out, scientists with Japan’s Aerospace Exploration Agency announced in a news conference on August 23.

Hayabusa2 arrived at the 1,000-meter-wide asteroid on June 27, and has been scanning the surface since. More than 100 mission team members met on August 17 to choose the first spots for the spacecraft to land.

The team decided that the two landers, called MINERVA-II and MASCOT, will touch down on the diamond-shaped asteroid’s surface first. MINERVA-II, which carries small hopping rovers equipped with cameras and other instruments, will land at a spot near Ryugu’s north pole on September 21. MASCOT, a tumbling rover, will land closer to the south pole on October 4. The craft will roam the landscape making measurements of the asteroid’s composition, temperature and magnetic properties.
The main body of Hayabusa2 will join them in late October, touching down at a point near the asteroid’s equator and gathering a sample of dust there.

The mission team looked for regions 100 meters in diameter that were relatively flat, with slopes less than 30 degrees and with few boulders. Ryugu turned out to be strewn with more boulders than expected based on the first Hayabusa mission, which brought back bits of a smoother asteroid called Itokawa.

But the observations from orbit suggest Ryugu’s surface is well-mixed, meaning that no matter where Hayabusa2 lands, it has a good chance of picking up something interesting. The spacecraft will collect samples from two other, still unknown sites over the next 15 months before returning the samples to Earth in 2020.