There are a lot of unknowns when it comes to understanding how the mammalian respiratory tract responds to allergens, but a study published January 17 in Science Immunology, offers new insight. Researchers identified a group of epithelial cells in the mouse nose that are capable of responding to allergens directly and also to ATP released in response to allergens. When exposed to allergens, these so-called brush cells secrete cysteinyl leukotrienes, proinflammatory lipids that have been previously shown to come mostly from immune cells and have been linked to asthma and allergies.
“We have been interested in how allergens are recognized by the airway epithelium and how they drive immune responses that are biased towards allergic inflammation,” says coauthor Lora Bankova of Harvard Medical School.
Previous research had shown that tuft cells, a solitary chemosensory cell type found in the intestine, are responsible for orchestrating immunity to parasitic worms in the gut, which trigger the same type of immune response as allergens. To determine whether there might be cells playing the same role in the airway epithelium, she and her colleagues investigated a similar cell type in the mouse trachea: brush cells. In work published in 2018, they analyzed the gene expression profile of brush cells and found that brush cell activation was important for airway inflammation.
In the trachea, brush cells are only about half of a percent of the total number of cells. These small numbers made it hard to do in vitro or ex vivo cultures in which it would be possible to directly stimulate them and see what happens, Bankova explains. So the research team looked for these cells elsewhere in the airway. In the current study they found that there are solitary chemosensory cells with similar transcriptional profiles to the tracheal brush cells present in much larger numbers in the mouse nose, where they contribute 4–8 percent of the total cells.
“Because they’re so abundant we were actually able to isolate them and study them directly to see what activates them, what can they produce in response to stimulation,” Bankova tells The Scientist. The researchers isolated nasal brush cells from mice and incubated them with ATP, which functions as a cellular stress or damage signal, or with allergens from dust mites or mold.
In response, the brush cells released proinflammatory cysteinyl leukotrienes at amounts comparable to or exceeding what immune cells produced when the research team stimulated them. Brush cell production of these lipids, and the lower levels generated by other cell types, indicate that the epithelial cells are likely the dominant source of cysteinyl leukotrienes in the nose. The researchers also showed that mice without brush cells had a reduced amount of allergic inflammation in response to an allergen.
“Allergen activates them, and they’re important for generating the cysteinyl leukotrienes and allergic inflammation in that setting,” says Bankova. She explains that it’s likely that they’re also responding to other sorts of damage in the airway epithelium because they release cysteinyl leukotrienes in response to ATP as well.
That ATP serves as a ligand for brush cells is the most surprising finding, says Christoph Schneider, a biologist at the University of Zurich who did not participate in the study. He adds that open questions include whether or not brush cells are the sole target of ATP and sole source of cysteinyl leukotrienes and “whether this is true only for these airway brush cells or whether the same ATP effect is also observed in other situations, in other organs, et cetera.”
“To develop an asthma-like syndrome — especially if it’s allergic in nature—you have to have sensitization and then a subsequent response to challenge, so this is providing a mechanism by which the epithelium by itself is critical for sensitization,” says Teal Hallstrand, a pulmonary physician at the University of Washington who was not involved in the work. “I’d be very excited to learn about whether or not people with asthma have an alteration in the number of these cells in their airways and what specific physiological effect that has.”
Researchers have found that people are more gloomy in November, so Blue Monday is not the most depressing day of the year.
In 2005 Dr Cliff Arnall, formerly of Cardiff University, came up with a light-hearted formula for predicting the day of the year when people are most despondent, based on factors including weather, debts, time since Christmas and motivation.
He concluded unhappiness peaked at the third Monday in January as festive bills roll in and the post-holiday buzz wears off, which would fall this year on Monday 20th.
But new analysis of 18.7 million sick days taken by 600,000 employees at FTSE 100 companies and NHS Trusts over 15 years, shows that January never makes it into top month for people taking time off for mental health issues.
In fact for 13 out of the 15 years, most mental health sick days were taken in November (47 per cent) or December (40 per cent) with the 14th and 27th of November and December 1, each appearing twice in the list.
In contrast, the main reasons given for workplace absence recorded in January are coughs, colds and the flu.
The year 1996 was not a good one for me. Early in the year, I completed work for the Intergovernmental Panel on Climate Change—the IPCC. I had served as convening lead author for the climate change detection and attribution chapter of the IPCC’s Second Assessment Report. Twelve simple words captured the bottom-line finding of our chapter: “The balance of evidence suggests a discernible human influence on global climate.” These twelve words changed my life.
The IPCC report was published in the spring. The fallout was swift. The “discernible human influence” finding threatened the interests of powerful organizations and individuals. At a time of ethnic cleansing in Bosnia, an energy lobbying group called the Global Climate Coalition (GCC) accused me of “scientific cleansing.” The GCC made the demonstrably incorrect claim that I had purged all scientific uncertainty from Chapter 8. This allegation was deeply disturbing. My family had been “cleansed” by the Nazis in the Second World War; the GCC’s words reopened old wounds.
After the Global Climate Coalition’s opening salvo, others weighed in. The June 12 issue of the Wall Street Journal ran an opinion piece by Fred Seitz, a past president of the U.S. National Academy of Sciences. In his op-ed, Seitz wrote that in more than 60 years as a leading light in American science, he had “never witnessed a more disturbing corruption of the peer-review process than the events that led to this IPCC report.” Seitz blamed me personally for this “corruption.”
Seitz was not a climate scientist, had not been involved with the IPCC’s Second Assessment Report, and had not attended the key IPCC Plenary Meeting in Madrid at which the “discernible human influence” finding was finalized. His incorrect claims regarding the IPCC’s peer-review process were eventually rebutted by the IPCC leadership and by scientists involved with the IPCC report. But the reputational damage was already done. Untruths move quickly. The truth moves slowly.
My personal low point was in July 1996. I was in Oakland, participating in the jury selection for a trial. I checked my voicemail during a break in the selection proceedings. An urgent message informed me that Representative Dana Rohrabacher had begun to investigate the research funding I received from the U.S. Department of Energy. Writing to then Secretary of Energy Hazel O’Leary, Representative Rohrabacher noted that the allegations made against me by the GCC and others were of “great concern” to him. This was clearly a serious new development.
Back to the courtroom in Oakland. Immediately after I learned of Representative Rohrabacher’s letter, jury selection continued. Soon it was my turn to answer questions regarding my suitability to serve as a juror. The presiding judge asked me whether I’d ever been the victim of a crime. It was hard to respond. In front of dozens of other prospective jurors, I replied that my three-and-a-half-year-old son Nick had been taken to Germany by his mother and that I was not sure if and when he would return. In an unsteady voice, I explained that I urgently needed to find Nick, but could not leave the country as my U.S. passport had expired.
The judge excused me from jury service. Later that summer I traveled to Europe to search for my son. I filed papers in Germany under the Hague Convention on the Civil Aspects of International Child Abduction. The Hague Convention proceedings concluded in September 1996. Nick was returned to the United States later that month. I continue to have the extraordinary privilege of being an integral part of his life.
In the last few days I’ve had the opportunity to reflect on this experience. I am profoundly grateful that the Hague Convention exists. If it did not, I might have been nothing more than a ghost—a rapidly fading memory in a young child’s mind.
International conventions, accords and treaties are of great value in our complex world. They provide a means for resolving conflicts between individuals (as in my case) and between nations. They stipulate minimum standards of human behavior. Don’t torture. Don’t use land mines or chemical weapons. Don’t test nuclear weapons. Don’t destroy our planetary life-support system by treating the atmosphere as “an unpriced sewer.” Don’t commit war crimes.
It is of concern that President Trump does not ascribe to all of these minimum standards of human behavior. The president has threatened to target sites “important to Iran & the Iranian culture,” and to hit these targets “VERY FAST AND VERY HARD.” Such behavior would contravene multiple international conventions. Destroying another nation’s cultural heritage is a war crime.
One lesson I learned from my IPCC experiences is that words matter. The 12 words from Chapter 8 mattered. They changed the world. And the president’s words matter. Threats to abrogate international law cannot be dismissed as idle tweeting, or as a joke. They cannot become the new normal.
Soon 100 senators will have to decide whether their primary allegiance is to the U.S. Constitution or to Donald J. Trump. If facts matter, the balance of evidence suggests that the Senate’s decision should be simple. If facts no longer matter, this country will be forever diminished.
Researches have shown that not only cats can eat the flesh of their deceased hosts. Even hamsters are capable of such behavior.
A November 2019 paper described two feral cats who had taken to eating decomposing bodies at Colorado Mesa University’s (CMU) Forensic Investigation Research Station (FIRS)—also known as a body farm.This is not the first case of cats chowing down on their owners. In fact, cats aren’t the only pets who have been known to eat their humans, either—dogs have also exhibited this kind of behavior.
The picturesque campus of Colorado Mesa University (CMU) stands in stark contrast to the school’s Forensic Investigation Research Station (FIRS), where a body farm is home to several decomposing corpses—and the two feral cats who fed on them.
In 2017, when CMU student and the co-author of a paper detailing these carnivorous kitties sat down to review research footage, she was stunned to see a feral cat eating one of the bodies. A few months later, another cat had taken to eating another corpse. They both managed to get down to the bone.
Per the November 2019 report in the Journal of Forensic Sciences, the cats also showed a preference for soft tissue, specifically in the shoulders and arms of the bodies. Strangely, cats are known as predators, but these feral specimens appeared perfectly content scavenging bodies in the early stages of decomposition.
At the time the footage was captured, 40 bodies were on display but both cats continually returned to the same corpse they initially dined on—“one almost nightly for 35 nights straight,” reports The Washington Post. Garcia told the Post that one of the theories as to why the cats returned to the same bodies is because cats are “picky eaters,” who “stick with” food once they try it and like it.
And it’s not just cats and dogs—there are reported cases of hamsters scavenging human bodies postmortem. Carolyn Rando, a forensic anthropologist at London’s UCL Institute of Archaeology, says that when an animal becomes distressed, it can attempt to rouse its owner by nudging the body and can begin to nibble if there’s no response. If blood is drawn, it’s very possible that “instinct” takes over and causes the animal to begin eating.
“Yes, your pets will eat you when you die, and perhaps a bit sooner than is comfortable,” Rando told BuzzFeed News in 2015, referring to the case where a dog began to eat its owner who was not dead, but merely passed out drunk. The woman ultimately died.
Our pets might be our best friends, but at the end of the day—it’s a dog eat human world out there.
The researchers have uncovered hints about how the cephalopod’s brain became so huge, and how it accomplishes such impressive camouflage.
Up until 2006, most of our clues about the giant squid’s very existence came in the form of their washed-up, slimy corpses on beaches or through their beaks, which have been uncovered from the bellies of sperm whales. When the first-ever live footage of a giant squid was captured that year, just off of Japan’s Ogasawara Islands, we caught our first real glimpse of the magnificent cephalopod while still alive.
Fourteen years later, we’ve seen footage of the giant squid in its natural habitat, deep below the ocean’s waves, where the sun can’t reach—but the beasts are still fleeting and still difficult to study.
That’s why it’s such a huge deal that researchers have finally put together a draft genome sequence of the giant squid. It could help answer questions about how this mollusk grew to become over 40 feet long. The stuff of nightmares. Fodder for sailors’ tales of krakens.
“The elusiveness of the species makes it difficult to study,” the authors of the genome research, published in the scientific journal GigaScience, wrote in the abstract. “Thus, having a genome assembled for this deep-sea dwelling species will allow several pending evolutionary questions to be unlocked.”
The research team, led by Rute da Fonseca at the University of Copenhagen, found that just as the giant squid is absolutely humongous, so is its genome. With about 2.7 billion DNA base pairs, its genome is about 90 percent the size of the human genome. Still, that size in and of itself is not that telling. A rare Japanese flower called the Paris japonica, for instance, has 149 billion base pairs, which makes it about 50 times larger than the human genome.
The scientists extracted DNA for this analysis from a single giant squid, also known by the scientific name Architeuthis du. Because a giant squid has never been caught and kept alive before, the DNA sample came from a dead giant squid. While genome analysis points to some of the giant’s secrets—like how its brain grew to become the largest of the invertebrates and how it manages to camouflage its huge body so well—there’s still plenty that the researchers say can’t be told through genome sequencing just yet. For example, we still don’t know how the giant squid mates or what it eats.
Caroline Albertin, Hibbitt Fellow at Marine Biological Laboratory in Woods Hole, Massachusetts, is an expert on slippery creatures like the octopus and the squid. In 2015, she led the team that uncovered the very first cephalopod genome for the California two-spot octopus, Octopus bimaculoides.
Working on the giant squid genome, she noticed some similarities between it, the two-spot octopus, and the other three cephalopods that have had their genomes sequenced to date. In almost all animals, important developmental genes like Hox and Wnt are present.
In the giant squid, these were only present in single copies, which means the huge invertebrates didn’t become huge through whole-genome duplication, a biological strategy that allowed vertebrates to grow larger throughout the course of evolution. Indeed, it looks like invertebrates take a whole different approach to growth than vertebrates.
Whole-genome duplication is a process by which an organism creates additional copies of the entire genome of its species. Most living things that reproduce sexually, including humans, contain two copies of their full genome, inherited from each parent. This means humans are diploid, or contain two full sets of chromosomes. Whole-genome duplication increases the rate and efficiency by which organisms can acquire new biological traits.
So to fully understand why these cephalopods grow to over 40 feet in length, researchers will have to further probe the giant squid genome.
“A genome is a first step for answering a lot of questions about the biology of these very weird animals,” Albertin said in a press release. “While cephalopods have many complex and elaborate features, they are thought to have evolved independently of the vertebrates. By comparing their genomes we can ask, ‘Are cephalopods and vertebrates built the same way or are they built differently?'”
A Little Brain
One of the truly remarkable characteristics of the giant squid is its brain, which is rather complex and strangely shaped. Smithsonian describes its brain as “shaped like a donut.” And weirdly enough, its esophagus actually runs through that hole.
But here’s the catch: While the brain is colossally complicated, it’s actually pretty small as a share of the giant squid’s full body mass. While a giant squid can weigh up to one ton, based on the carcasses that have washed ashore and the limited video evidence we’ve seen of the them, their brain only weighs about 100 grams, which is just over one-fifth of a pound. Still, that’s the largest invertebrate brain on record.
Albertin and the rest of the research team working on the giant squid genome noticed the presence of more than 100 genes in the protocadherin family, which “are thought to be important in wiring up a complicated brain correctly,” she said. Usually, these genes aren’t found in invertebrates, so it’s hard to say what exactly this finding means. However, Albertin also identified protocadherins in the octopus genome she studied in 2015.
Camouflage for Days
Unique to cephalopods, reflectins are a gene family present in the giant squid’s genome that can help to camouflage them while stalking prey or trying to escape from one of their few natural predators, the sperm whale.
“Reflectins encode a protein that is involved in making iridescence,” Albertin said. “Color is an important part of camouflage, so we are trying to understand what this gene family is doing and how it works.”
Since only a few types of cephalopods have had their genomes sequenced—and because reflectins are so far only present in this class of animals—it’s difficult to say exactly how the proteins work. Finding them in the giant squid will help to propel research on them.
“Having this giant squid genome is an important node in helping us understand what makes a cephalopod a cephalopod,” Albertin said. “And it also can help us understand how new and novel genes arise in evolution and development.”
Mysterious drone swarms have been seen flying in Colorado, Nebraska and Wyoming at night since December, sometimes over locations believed to house nuclear missile silos. A federal task force has been formed to investigate the drones’ origin and purpose.
The Phillips County Sheriff’s Office in Colorado reported the first drones on 20 December. There have been hundreds of sightings since, some of groups of drones flying in grid patterns.
Some observers assumed the drones were part of a military exercise, but the US Air Force has denied involvement. There is no evidence of malicious intent, although the drone operators are breaking US regulations governing flying at night.
The drones are described as resembling model aircraft with a wingspan of around 2 metres. None has been recovered or even photographed. Similar drones are widely available online for a few hundred dollars.
Robert Bunker of the US Army War College’s Strategic Studies Institute in Pennsylvania says the scale of operation suggests it is the work of an organisation such as a university or government, rather than a lone individual – assuming the drones actually exist.
“The first question that the task force has to rule out is if we are not dealing with social media hype. Have these drone swarm sightings now turned into an urban legend?” says Bunker.
Richard Gill of UK company Drone Defence says that real drone sightings may have led to a number of false reports.
“People become hypersensitive after a scare,” he says. “Everything with a flashing light will get reported as a mystery drone.”
Small drones are elusive though, and taking photos of them at night is virtually impossible. Even locating them on radar is difficult.
“Small drones have a low metal content, so a normal radar simply passes through them,” says Gill. “Detecting them requires a special type of radar which usually has a range of just a few miles.”
While the task force is said to be looking at getting a fix on a radio controller on the ground, Gill says its best bet may be to bring one of the drones down, probably with a jammer. Although usually illegal in the US, jammers are permitted when protecting national assets.
“There’s a high probability you could get the GPS location of the launch site from the drone,” says Gill. “You can also get lots of other forensic information, such as picking up fingerprints and DNA and, if it’s homebuilt, comparing it to the construction of other drones on file.”
A captured drone would also be hard evidence. Similar drone sightings around London Gatwick airport in 2018 prompted the deployment of defences, and new counter-drone protection has just been introduced.
As with Gatwick though, the mystery drone sightings may simply cease, leaving the riddle of the drones’ source and motive – and even their existence – forever unsolved.
The world’s oceans were warmer in 2019 than it had ever been before, reported scientists.
The report comes at a time when studies have linked rising ocean water temperatures to manmade pollution. Researchers say the rate of warming is speeding up and may cause a planet-wide disaster.
The oceans take in more than 90 percent of the extra heat created by carbon dioxide and other greenhouse gas emissions. Greenhouse gases are a product of pollution from factories, driving motor vehicles and other human activities.
Scientists are able to measure the rate of global warming when they compare current ocean water temperatures with those measured over the past few years.
For a better understanding of ocean warmth, scientists from around the world studied records shared by China’s Institute of Atmospheric Physics (IAP). They found that the latest water temperature was 0.075 degrees Celsius higher than the average temperature from 1981 to 2010. Their findings were published in the scientific journal Advances in Atmospheric Sciences.
Effects of warmer oceans
The scientists pointed to the many extreme weather events of 2019 as one effect of warmer oceans. They added that warmer water also endangers some sea creatures and causes higher sea levels.
Lijing Cheng is with the International Center for Climate and Environmental Sciences at the IAP. He also was the lead author of a paper on the study. He says the heat the oceans have taken in to make the temperature change amounts to 228 Zetta Joules (228 billion trillion Joules) of energy.
“That’s a lot of zeros indeed,” he said. “To make it easier to understand, I did a calculation… The amount of heat we have put into the world’s oceans in the past 25 years equals to 3.6 billion Hiroshima atom-bomb explosions.”
One hundred hair dryers per person
Michael Mann is director of the Earth System Sciences Center at Penn State University in the United States. He says the energy that caused the warming is equal to “everyone on the planet running a hundred hairdryers or a hundred microwaves continuously for the entire year.” He spoke to the French news agency AFP.
The past five years are the five hottest years for the ocean since scientists began keeping records, the study found.
John Abraham is a co-author of the paper. He said it is important to “understand how fast things are changing. The key to answering this question is in the oceans — that’s where the vast majority of heat ends up. If you want to understand global warming, you have to measure ocean warming.”
Abraham is a professor of mechanical engineering at the University of St. Thomas in Minnesota.
Target limit to global warming
In 2015, world leaders signed the Paris Agreement as part of efforts to limit climate change. The agreement took effect the following year. It aims to limit global temperature increases to “well below” 2 degrees Celsius, and to 1.5 degrees Celsius if at all possible.
There has been about 1 degree Celsius of warming since the start of the Industrial Revolution 200 years ago. Yet the result of rising water temperatures is not evenly spread in the world’s oceans. The report says that warmer temperatures are partly to blame for heavy rainfall in Indonesia and the drying of Australia, leading to wildfires in Australia and the Amazon.
Mann explained that there is still hope for the climate to recover from this temperature increase. “If we stop warming the planet, heat will continue to diffuse down into the deep ocean for centuries until eventually stabilizing.”
Scientists had developed ‘Living concrete’ which can heal its own cracks and even ‘give birth’ to new bricks.
The new material is a mixture of sand and bacteria, which can act as both a structural, load bearing substance, but can also carry out biological functions, like reproduction.
It was created by scientists at the University of Colorado Boulder who admit it would not look out of place in the laboratory of a mad scientist.
“It looks like a Frankenstein-type material,” said senior author Dr Wil Srubar, who heads the Living Materials Laboratory.
“That’s exactly what we’re trying to create – something that stays alive. We use photosynthetic cyanobacteria to biomineralize the scaffold, so it actually is really green.”
To create the living material, scientists first created a scaffold out of sand and a water-based gel for the bacteria to grow in, then allowed the bugs to proliferate and mineralise, a process similar to the formation of seashells in the ocean.
The hydrogel-sand brick is not only alive, but it also reproduces. While stable when dry, it springs back to life with an increase in temperature and humidity, and enters a new growth phase.
By splitting the brick in half, the bacteria can grow into two complete bricks with the help of adding a little extra sand, hydrogel, and food.
Scientists have solved a 50-year-old mechanics problem that could change how statisticians run simulations and draw conclusions. The question is this: Is a 2D liquid different from a 3D liquid? The answer seems intuitive, but isolating and proving it has taken decades. “Our findings help to explain many puzzling differences between the dynamical properties of two- and three-dimensional liquids, which had been reported in the scientific literature,” says lead study author Massimo Pica Ciamarra in the press release.
Researchers who study fluid dynamics go back at least as far as ancient Greece, but people have probably looked at and wondered about water in particular since the beginning of human consciousness. You likely made a soda-bottle tornado in elementary school, which inducts you as a fluid dynamicist as well. This example is good for illustrating the basic idea of Ciamarra and his team’s paper. A soda-bottle tornado is clearly a three-dimensional item, but the liquid is directed by a drain that reduces the chaos you’d find in, say, a fishtank full of water.
In 3D liquids, particles swirl in a chaotic way called Brownian motion, without any sense of collective motion or memory. (Turbulence and vortices have their own entire branch of fluid dynamics.) In 2D liquids cooled to a certain point, these researchers found, particles can “remember” where they were over surprisingly long distances, which preempts Brownian motion and gives these liquids more in common with 2D solids than with 3D liquids at the same temperature. The particles end up moving in collected masses within the overall space.
A 2D liquid is just what it sounds like. In research, a completely 2D space, meaning a flat sheet with hypothetically no “thickness” or a thickness of one relevant unit like atom or molecule, is assigned the properties of a liquid. In real life, this means liquids can be studied under microscopes. (If you ever did a cheek swab and dilution and prepared a slide in biology class, you also studied a 2D liquid, technically.)
Los Alamos National Laboratory scientist Robert Ecke, who wasn’t involved in this research, explains in a paper why it’s useful to do this:
“In fluid dynamics, a reduction in dimensionality is important because there are many mechanisms that generate large spatial anisotropy with two spatial dimensions dominant compared with the third.”
The Brownian motion and other complications in 3D liquids are reduced in 2D liquids.
Studying a 2D reduction of the “real” 3D world makes some phenomena more noticeable and easier to observe. Especially when computer models are involved, there are also questions of the time, complexity, and computing power it takes to run 3D simulations compared with 2D. Fluid dynamics in action can look like chaos because of the huge number of different forces interacting. Remember how hard it was to measure just five birds in flight, using ultra slow motion and sensors?
This complexity is part of why it’s been so difficult to isolate causes and differences between 2D and 3D models. Scientists could guess many of the ways the two models differ, but others were perplexing even within the understanding of the chaos of fluid dynamics research.
The world’s first living robots have been built using stem cells from frog embryos, in a strange machine-animal hybrid that scientists say is an ‘entirely new life-form.’
Dubbed ‘xenobots’ because they are constructed of biological material taken from the Xenopus laevis frog, the little bots are the first to be constructed from living cells.
Researchers are hopeful they could be programmed to move through arteries scraping away plaque, or swim through oceans removing toxic microplastic.
And because they are alive, they can replicate and repair themselves if damaged or torn.
“These are novel living machines,” said Dr Joshua Bongard, a computer scientist and robotics expert at the University of Vermont, who co-led the new research.
“They’re neither a traditional robot nor a known species of animal. It’s a new class of artifact: a living, programmable organism.”
Living organisms have often been manipulated by humans in the past, right down to their DNA code, but this is the first time that biological machines have been built completely from scratch.
Scientists first used the Deep Green supercomputer cluster at the University of Vermont to create an algorithm that assembled a few hundred virtual skin and heart cells into a myriad forms and body shapes, for specific tasks.