Olfactory neurons adapt to the surrounding environment

Cross-section of the nasal cavity of a mouse (wide view). Within the dense population of olfactory neurons (in blue), the olfactory neurons expressing a specific type of receptor (Olfr151) are marked in bright green.
Credit: Madlaina Boillat

Olfactory receptors, present on the surface of sensory neurons in the nasal cavity, recognize odorant molecules and relay this information to the brain. How do these neurons manage to detect a large variability of signals and adapt to different levels of stimulation? A joint team from the Faculty of Science and the Faculty of Medicine of the University of Geneva (UNIGE) investigated the gene expression profile of these neurons in the presence or absence of odorant stimulation. The scientists discovered an unsuspected variability in these profiles depending on the expressed olfactory receptor and previous exposure to odors. These results, to be read in the journal Nature Communications, highlight a wide range of identities of olfactory neurons, and their adaptation to the surrounding environment.

In mammals, the perception of odors is ensured by millions of olfactory neurons, located in the mucosa of the nasal cavity. These neurons have on their surface receptors able to bind specifically to an odorant molecule. Each olfactory neuron expresses only one gene coding for an olfactory receptor, chosen from a repertoire of about 450 in humans and 1,200 in mice.

Unselfish behavior has evolutionary reasons

Florida scrub jays,
Image: Wikimedia commons / Richard Crossley

Altruistic behavior is often seen as an exclusively human characteristic. However, behavioral research has uncovered numerous examples of altruistic behavior in the animal kingdom. In a new study, researchers at the University of Bern show that animals that help others “selflessly” to raise their young generate an evolutionary advantage.

Altruism is defined as doing something that benefits someone else, at a cost to oneself. In the animal kingdom, the most astonishing examples of this selflessness occur in the rearing of the next generation. Animal societies that exhibit cooperative breeding include cichlids in Lake Tanganyika, some mammals, many bird species, and numerous insects. In these societies, typically a single, dominant breeding pair produces young, and the other members of the group help raise them. These members of the group are therefore acting altruistically by the care of young that are not their own.

This type of care makes sense from an evolutionary perspective when the young are siblings of the carers – the brood care helpers are successfully handing down the genes that stimulate the care via their siblings, with whom they share these genes. However, from an evolutionary perspective it does not seem to make sense to look after young with whom you are not related. So why do unrelated group members often help to raise “foreign” young? A new study in the Science Advances academic journal by Irene Garcia Ruiz and Michael Taborsky from the Institute for Ecology and Evolution at the University of Bern, in collaboration with Andres Quinones from the University of Los Andes in Bogota, Colombia, and the University of Neuchâtel, reveals how this altruistic care of young can evolve by natural selection.

Black Hole Orrery

This visualization shows 22 X-ray binaries in our Milky Way galaxy and its nearest neighbor, the Large Magellanic Cloud, that host confirmed stellar-mass black holes. The systems are shown at the same physical scale, and their orbital motion is sped up by nearly 22,000 times. The view of each binary replicates how we see it from Earth. The star colors range from blue-white to reddish, representing temperatures from 5 times hotter to 45% cooler than our Sun.

While the black holes appear on a scale reflecting their masses, all are depicted using spheres larger than actual size. Cygnus X-1, with the largest companion star shown, is the first black hole ever confirmed and weighs about 21 times more than the Sun. But its surface – called its event horizon – spans only about 77 miles (124 kilometers). The enlarged spheres also cover up visible distortions produced by the black holes’ gravitational effects.

‘Transformative’ effects of mass gatherings like Burning Man are lasting

Photo by Curtis Simmons, Flickr: simmons_tx

Throughout history, mass gatherings such as collective rituals, ceremonies, and pilgrimages have created intense social bonds and feelings of unity in human societies. But Yale psychologists wondered if modern day secular gatherings that emphasize creativity and community serve an even broader purpose.

The research team studied people’s subjective experiences and social behavior at secular mass gatherings, such as the annual Burning Man festival in the Nevada desert. They found that people who reported transformative experiences at the gatherings felt more connected with all of humanity and were more willing to help distant strangers, the researchers report May 27 in the journal Nature Communications.

“We’ve long known that festivals, pilgrimages, and ceremonies make people feel more bonded with their own group,” said Daniel Yudkin, a postdoctoral researcher and first author of the paper. “Here we show that experiences at secular mass gatherings also have the potential to expand the boundaries of moral concern beyond one’s own group.”

The research team, led by M.J. Crockett, an associate professor of psychology at Yale, conducted field studies of more than 1,200 people attending multi-day mass gatherings in the United States and United Kingdom: Burning Man, Burning Nest, Lightning in a Bottle, Dirty Bird, and Latitude, all events that feature art, music, and self-expression.

Unlocking the Secrets of the Brain

Roberto Vargas

Researchers at Carnegie Mellon University have explored the regions of the brain where concrete and abstract concepts materialize. A new study now explores if people who grow up in different cultures and speak different languages form these concepts in the same regions of the brain.

"We wanted to look across languages to see if our cultural backgrounds influence how we understand, how we perceive abstract ideas like justice," said Roberto Vargas, a doctoral candidate in psychology at the Dietrich College of Humanities and Social Sciences and lead author on the study.

Vargas is continuing fundamental research in neural and semantic organization initiated by Marcel Just, the D.O. Hebb University Professor of Psychology. Just began this process more than 30 years ago by scanning the brains of participants using a functional magnetic resonance imaging (fMRI) machine. His research team began by identifying the regions of the brain that light up for concrete objects, like an apple, and later moved to abstract concepts from physics like force and gravity.

The latest study took the evaluation of abstract concepts one step further by exploring the regions of the brain that fire for abstract objects based on language. In this case, the researchers studied people whose first language is Mandarin or English.

"The lab's research is progress to study universalities of not only single concept representations, but also representations of larger bodies of knowledge such as scientific and technical knowledge," Just said. "Cultures and languages can give us a particular perspective of the world, but our mental filing cabinets are all very similar."

Quest for elusive monolayers just got a lot simpler

Researchers can process 100 images covering 1 centimeter x 1 centimeter-sized samples like this one in around nine minutes using a new system that greatly simplifies the often-tedious search for monolayers in the lab.
Credit: University of Rochester photo / J. Adam Fenster

One of the most tedious, daunting tasks for undergraduate assistants in university research labs involves looking for hours on end through a microscope at samples of material, trying to find monolayers.

These two-dimensional materials—less than 1/100,000th the width of a human hair—are highly sought for use in electronics, photonics, and optoelectronic devices because of their unique properties.

“Research labs hire armies of undergraduates to do nothing but look for monolayers,” says Jaime Cardenas, an assistant professor of optics at the University of Rochester. “It’s very tedious, and if you get tired, you might miss some of the monolayers or you might start making misidentifications.”

Even after all that work, the labs then must doublecheck the materials with expensive Raman spectroscopy or atomic force microscopy.

Jesús Sánchez Juárez, a PhD student in the Cardenas Lab, has made life a whole lot easier for those undergraduates, their research labs, and companies that encounter similar difficulties in detecting monolayers.

Gene Linked to Severe Learning Disabilities Governs Cell Stress Response

Like superheroes of the cell, the protein Rad6 (red), and its partner Uba1 (blue) respond to environmental stress by modifying the protein-producing ribosomes (purple) to stop their maintenance program. 
Credit: Dinachi Okonkwo

A gene that has been associated with severe learning disabilities in humans has been found to also play a vital role in cells’ response to environmental stress, according to a Duke University study appearing in the journal Cell Reports.

Cells are stressed by factors that may damage them, such as extreme temperatures, toxic substances, or mechanical shocks. When this happens, they undergo a range of molecular changes called the cellular stress response.

“Every cell, no matter from which organism, is always exposed to harmful substances in their environment that they have to deal with all the time,” said Gustavo Silva, assistant professor of biology at Duke and senior author on the paper. “Many human diseases are caused by cells not being able to cope with these aggressions.”

During the stress response, cells press pause the genes related to their normal housekeeping activities, and turn on genes related to crisis mode. Just like in a house being flooded, they put down the window cleaner, turn off the TV, and run to close the windows, then they patch holes, turn on the sump pump, and if needed, rip up carpet and throw away irreparably damaged furniture.

British coral predicted to be resilient to climate change

Pink sea fan / Warty coral (Eunicella verrucosa), Lundy Island Marine Conservation Zone, Devon, England, UK,

An iconic coral species found in UK waters could expand its range due to climate change, new research shows.

The pink sea fan is a soft coral that lives in shallow waters from the western Mediterranean (southern range) to north-west Ireland and the south-west of England and Wales (northern range).

The species is classified as "vulnerable" worldwide and it is listed as a species of principal importance in England and Wales under the NERC Act 2006.

The new study, by the University of Exeter, found that the species is likely to spread northwards – including around the British coast – as global temperatures rise.

The results could be used to identify priority areas to protect pink sea fan populations.

"We built models to predict the current and future (2081-2100) habitat of pink sea fans across an area covering the Bay of Biscay, the British Isles and southern Norway," said Dr Tom Jenkins, from the University of Exeter.

Researchers aim X-rays at century-old plant secretions for insight into Aboriginal Australian cultural heritage

Century-old plants exudate samples in amber jars. Researchers mapped the chemistry of these samples using high-energy photons. Scientists can analyze other historical artifact chemistries by applying this technique in the future.
Credit: Flinders University, South Australia, Kaurna Country

By revealing the chemistry of plant secretions, or exudates, these studies build a basis for better understanding and conserving art and tools made with plant materials.

For tens of thousands of years, Aboriginal Australians have created some of the world’s most striking artworks. Today their work continues long lines of ancestral traditions, stories of the past and connections to current cultural landscapes, which is why researchers are keen on better understanding and preserving the cultural heritage within.

In particular, knowing the chemical composition of pigments and binders that Aboriginal Australian artists employ could allow archaeological scientists and art conservators to identify these materials in important cultural heritage objects. Now, researchers are turning to X-ray science to help reveal the composition of the materials used in Aboriginal Australian cultural heritage – starting with the analysis of century-old samples of plant secretions, or exudates.

Aboriginal Australians continue to use plant exudates, such as resins and gums, to create rock and bark paintings and for practical applications, such as hafting stone points to handles. But just what these plant materials are made of is not well known.

Chemists reveal how tau proteins form tangles

MIT chemists have used nuclear magnetic resonance (NMR) spectroscopy to reveal how two different forms of the Tau protein mix to form the tangles seen in the brains of Alzheimer’s patients. 
Credit: Aurelio Dregni/Nadia El-Mammeri/Hong Lab at MIT

One of the hallmarks of Alzheimer’s disease is the presence of neurofibrillary tangles in the brain. These tangles, made of tau proteins, impair neurons’ ability to function normally and can cause the cells to die.

A new study from MIT chemists has revealed how two types of tau proteins, known as 3R and 4R tau, mix together to form these tangles. The researchers found that the tangles can recruit any tau protein in the brain, in a nearly random way. This feature may contribute to the prevalence of Alzheimer’s disease, the researchers say.

“Whether the end of an existing filament is a 3R or 4R tau protein, the filament can recruit whichever tau version is in the environment to add onto the growing filament. It is very advantageous for the Alzheimer’s disease tau structure to have that property of randomly incorporating either version of the protein,” says Mei Hong, an MIT professor of chemistry.

Hong is the senior author of the study, which appears today in Nature Communications. MIT graduate student Aurelio Dregni and postdoc Pu Duan are the lead authors of the paper.