Endangered songbird challenging assumptions about evolution

By looking at this newly emerged bird, a University of Colorado Boulder-led research team found an 'evolutionary shortcut' for speciation

UNIVERSITY OF COLORADO AT BOULDER

Research News

 

Not all species may travel the same path to existence, at least according to new findings from the University of Colorado Boulder and collaborators.

This new research, out now in Science, looked at a newly discovered, endangered songbird located only in South America--the Iberá Seedeater--and found that this bird followed a very rare evolutionary path to come into existence at a much faster pace than the grand majority of species.

By comparing this bird to a closely related neighbor (the Tawny-Bellied Seedeater) in the same group (the southern capuchino seedeaters), the researchers determined that genetic shuffling of existing variations, rather than new random mutations, brought this species into existence--and their own behaviors are keeping them apart.

This species is one of only two known examples across the globe to have traveled this path, challenging the typical assumptions of how new species form.

"One of the aspects of this paper that makes it so cool is that we were able to address this question of how the Iberá Seedeaters formed from multiple different perspectives," said Sheela Turbek, a graduate student in ecology and evolutionary biology (EBIO) at University of Colorado Boulder and the study's lead author.

"Not only did we collect on-the-ground data on who mated with one another and the identity of their offspring, but we also generated genomic data to examine how similar these two species are on a genetic level. We then zoomed out further to look at where the Iberá Seedeater fits in the context of the broader capuchino group."

"Many studies will address one of these aspects or questions but not combine all of these different pieces of information into a single study."

The southern capuchino seedeaters are a group of recently evolved songbirds found throughout South America that is branching rapidly, with many of its species in the early stages of evolution. This family is best known for the dramatic variation with the males in terms of songs and plumage color, while the females are largely indistinguishable even to the most familiar researchers.

The Iberá Seedeater, the most recent member of this family, was first discovered in the remote, swampy grasslands of Iberá National Park in northern Argentina by study co-authors Adrián S. Di Giacomo and Cecilia Kopuchian from Centro de Ecología Aplicada del Litoral, Argentina, in 2001, and then described in scientific literature in 2016.

In that national park, though, are six other closely related species of capuchinos, including the Tawny-Bellied Seedeater, that breed closely beside each other. These species, despite occupying the same environment and eating the same food, rarely interbreed.

And so, researchers wondered why--and how--the Iberá Seedeater even came to be.

They explored these questions in two ways: First, they looked at how this new species may have formed by examining the ways in which its DNA differs from the Tawny-Bellied Seedeater, and second, looking at what mechanisms might be preventing it from interbreeding with the other species that occur in the park.

To do that, Turbek went down to Argentina for the breeding season for three years, staying two and a half to three months at a time, searching for and monitoring nests, collecting blood samples from adults and nestlings, and then, in the final year, performed a behavioral experiment to see whether plumage or song played a roll in terms of species recognition.

"The field work involved in collecting the assortative mating and behavioral data is extraordinarily hard, which is why these kinds of datasets rarely exist. This study and publication are a testament to Sheela's skill and hard work in the field," said Scott Taylor, an assistant professor in EBIO at University of Colorado Boulder, an author on the paper and Turbek's advisor.

What they found is that the two birds are closely related genetically, only distinguishable by the genes involved in plumage coloration. As well, they found that the males responded most aggressively to songs and plumage variations aligning with their own species.

This all means that the species could very well reproduce and hybridize--they just choose not to, therefore reinforcing their own reproductive barriers.

On a broader level, though, when comparing the Iberá Seedeater to other capuchino species, the researchers found that the Iberá Seedeater shares genomic variants with other capuchinos in these regions, but the variants have been shuffled to form a unique combination, which, the researchers argue, could be an evolutionary shortcut that most likely underlies much of the diversity among the different subspecies of this family.

"This is a really beautiful story about a process that we have never seen in quite this way before," says co-author Irby Lovette, director of the Fuller Evolutionary Biology Program at the Cornell Lab of Ornithology.

"The classic and most common evolutionary model for new species is the accumulation of genetic mutations when those species are separated by a geographic barrier over perhaps millions of years. But here we found that genetic shuffling can happen quickly and without geographical isolation. It's almost like 'instant speciation.'"

Leonardo Campagna, a research associate at the Cornell Lab of Ornithology and the senior author on the paper, agrees:

"This is the clearest example in birds of how reshuffling of genetic variation can generate a brand-new species."

The only other organism where this type of evolution has been seen, according to Turbek, is a group of fish found in Africa called the Lake Victoria cichlids.

"It's interesting to see this mechanism operating in something as different as birds," Turbek commented.

While this study focused in part on the role of male behaviors, the researchers are very interested in taking it one step further, examining the role that female choice may also play in reproduction.

"There are many more questions that we have to address," Turbek said.

###

Other researchers on the project include Melanie Browne with Centro de Ecologia Aplicada del Litoral in Corrientes, Argentina; Wesley M. Hochachka with the Cornell Lab of Ornithology; Dario A. Lijtmaer and Pablo L. Tubaro with Museo Argentino de Ciencias Naturales Bernardino Rivadavia, Buenos Aires, Argentina; Luis Fabio Silveira with Museu de Zoologia da Universidade de Sao Paulo, Sao Paulo, Brazil; and Rebecca J. Safran with CU Boulder.

Floating gardens as a way to keep farming despite climate change

Bangladesh's historic farming systems could offer a way forward

OHIO STATE UNIVERSITY

Research News

 

COLUMBUS, Ohio - Bangladesh's floating gardens, built to grow food during flood seasons, could offer a sustainable solution for parts of the world prone to flooding because of climate change, a new study has found.

The study, published recently in the Journal of Agriculture, Food and Environment, suggests that floating gardens might not only help reduce food insecurity, but could also provide income for rural households in flood-prone parts of Bangladesh.

"We are focused here on adaptive change for people who are victims of climate change, but who did not cause climate change," said Craig Jenkins, a co-author of the study and academy professor emeritus of sociology at The Ohio State University. "There's no ambiguity about it: Bangladesh didn't cause the carbon problem, and yet it is already experiencing the effects of climate change."

Bangladesh's floating gardens began hundreds of years ago. The gardens are made from native plants that float in the rivers - traditionally, water hyacinths - and operate almost like rafts, rising and falling with the waters. Historically, they were used to continue growing food during rainy seasons when rivers filled with water.

The farmers - or their families - layer the plants about three feet deep, creating a version of raised-bed gardens that float in the water. Then, they plant vegetables inside those rafts. As the raft-plants decompose, they release nutrients, which help feed the vegetable plants. Those vegetable plants typically include okra, some gourds, spinach and eggplant. Sometimes, they also include spices like turmeric and ginger.

Floating gardens are also in use in parts of Myanmar, Cambodia and India. The United Nations Food and Agricultural Organization has named Bangladesh's floating gardens a Globally Important Agricultural Heritage System.

But as climate change has affected the volume of water in those rivers - creating extreme highs and floods, along with extreme lows and droughts - floating gardens have become a way for rural farmers to keep producing food during unpredictable weather. Climate change increases weather extremes and the severity of flooding, and droughts as well.

The researchers wanted to understand whether Bangladesh's floating gardens could be a sustainable farming practice as climate change continues to cause floods and droughts, and to see whether the gardens bring better food security to individual households.

"They've got to be able to grow specific crops that can survive with minimal soil," said Jenkins, who is also a research scientist and former director of the Ohio State Mershon Center for International Security Studies. "And in Bangladesh, a lot of small farmers that had typically relied on rice crops are moving away from those because of the effects of climate change and better returns from alternative crops."

For this study, the researchers interviewed farming families who use floating gardens, and found strong evidence that floating gardens provide stability, both in the amount of food available to feed rural populations and in a farming family's income, despite the instability created by a changing climate.

They found that farmers typically use hybrid seeds, which must be repurchased each year, to grow a diverse range of vegetables in the floating gardens. The gardens are also susceptible to pests, so farmers end up spending some money on both pesticides and fertilizers. But even with those expenses, they found, benefits outweighed costs.

Generally, entire families work on the gardens, the researchers found: Women, children and the elderly prepare seedlings and collect aquatic plants to build gardens. Men cultivate the gardens and protect them from raiders. Some families also farm fish in the waters around their floating gardens.

One farmer told the research team that he earns up to four times as much money from the gardens as from traditional rice paddies.

Still, the system could use improvements, the researchers found. Farmers often take out high-interest loans to cover the investment costs of building the beds and stocking them with plants. Lower-interest loans from responsible government or non-governmental organizations could alleviate that burden, they found.

Coastal lupine faces specific extinction threat from climate change

WASHINGTON UNIVERSITY IN ST. LOUIS

Research News

 

IMAGE: CLIMATE CHANGE REPRESENTS A SPECIFIC EXTINCTION THREAT FOR AN ENDANGERED COASTAL LUPINE PLANT KNOWN AS TIDESTROM'S LUPINE (LUPINUS TIDESTROMII), FOUND AT THE POINT REYES NATIONAL SEASHORE, CALIFORNIA, UNITED STATES. view more 

CREDIT: ELEANOR PARDINI, WASHINGTON UNIVERSITY IN ST. LOUIS

Climate change is altering the world we share with all living things. But it's surprisingly difficult to single out climate change as an extinction threat for any one particular species protected under the Endangered Species Act.

To date, the U.S. Fish and Wildlife Service has only formally considered impacts from climate change in listing actions for four animal species and one alpine tree.

But the effects of climate change extend to temperate climates as well. A new analysis of population data published in the journal Ecosphere shows that climate change represents a specific extinction threat for an endangered coastal lupine plant.

Biologists including Eleanor Pardini at Washington University in St. Louis have tracked all of the known stands of Tidestrom's lupine, Lupinus tidestromii, at Point Reyes National Seashore north of San Francisco for more than 14 years.

If average temperatures increase by one degree Celsius (1° C, or about 1.8 degrees Fahrenheit) -- a conservative assumption -- the scientists project that 90% of individual lupine plants could be lost in the next 30 years.

"In general, it is fairly difficult to conclusively say that climate change is a species threat," said Pardini, assistant director of environmental studies at Washington University and senior lecturer in Arts & Sciences.

Modeling the threat of climate change requires long-term population data, which is difficult to collect and thus not available for most species.

"We were able to perform this analysis and show climate change is an important additional threat factor for this species because we have spent considerable effort collecting a long-term dataset," Pardini said.

An overlooked threat

To date, regulators have considered climate change in their listing actions only for four animal species: the polar bear, American pika, American wolverine and Gunnison sage-grouse.

Tidestrom's lupine is different, and not just because it's a plant. It's from a more seasonally mild coastal area -- not someplace that one might think would be rocked by a few degrees of rising temperatures. The animals that have been previously considered all occur in arctic, alpine or arid regions.

"While our results on L. tidestromii could be an isolated case, they suggest that the extinction threat posed by climate change might be overlooked in temperate biomes," Pardini said.

The delicate, purple-flowering lupine is part of a dune ecosystem along the west coast of the United States that is highly disturbed. In many of these coastal places, people have planted exotic plants to be able to develop and farm closer to the beach. Over time, exotic plants have over-stabilized dunes, disrupting wind and sand movement and harming plants and animals.

For the new study, Pardini worked with Tiffany Knight and Aldo Compagnoni, both of Martin Luther University Halle-Wittenberg and the German Centre for Integrative Biodiversity Research (iDiv) in Germany. Pardini and Knight have been tracking populations of Tidestrom's lupine at Point Reyes since 2005. Compagnoni joined the team as an expert in demographic modeling incorporating climate data.

The scientists produced population trajectories for all populations of the species at Point Reyes for the next 30 years.

"Using 14 years of demographic data from 2005 to 2018 and model selection, we found that survival and fertility measures responded negatively to temperature anomalies," said Compagnoni, first author of the new study. "We then produced forecasts based on stochastic individual-based population models that account for uncertainty in demographic outcomes."

If temperatures remain at the 1990-2018 average levels, the scientists expect that the number of individual lupine plants would double over the next 30 years. However, with a 1° C increase in temperature, the number of plants will instead drop off dramatically, with an expected 90% reduction in the number of individual plants.

This scenario is conservative, as even more dramatic increases in temperature than 1° C are projected for this region of California in the next 30 years.

"Despite large uncertainties, we predict that all populations will decline if temperatures increase by 1° Celsius," Compagnoni said. "Considering the total number of individuals across all seven populations, the most likely outcome is a population decline of 90%. Moreover, we predict local extinction is certain for one of our seven populations."

"Our species has a range so small that its response to climate cannot be inferred from its geographic distribution," Pardini said. "In these cases, long-term data collection becomes an important alternative option to assess the climatic vulnerability of a species."

Some rare species that are endemic to coastal habitats are currently protected by the Endangered Species Act and by various state listings.

Many Tidestrom's lupine populations are protected against development because they occur in a national park or state parks. However, Knight expressed general concern about the proposed new regulations that would allow coastal habitats to be excluded in the future because they are economically valuable to developers. Coastal plant communities provide a wide variety of valuable ecosystem services, such as mitigating the effects of coastal erosion and flooding.

###

A mouse's bite holds venomous potential, finds new study

Startling new evidence shows mammal salivary glands and snake venom glands share a common genetic foundation.

OKINAWA INSTITUTE OF SCIENCE AND TECHNOLOGY (OIST) GRADUATE UNIVERSITY

Research News

 

IMAGE: THE TAIWAN HABU (PROTOBOTHROPS MUCROSQUAMATUS) IS AN INVASIVE SPECIES THAT HAS BECOME WELL ESTABLISHED IN OKINAWA. view more 

CREDIT: OIST/STEVEN AIRD

We are not venomous, and neither are mice - but within our genomes lurks that potential, suggest scientists from the Okinawa Institute of Science and Technology Graduate University (OIST) and the Australian National University.

Reporting this week in PNAS, the researchers found that the genetic foundation required for oral venom to evolve is present in both reptiles and mammals.

The study also provides the first concrete evidence of an underlying molecular link between venom glands in snakes and salivary glands in mammals.

"Venoms are a cocktail of proteins that animals have weaponized to immobilize and kill prey, as well as for self-defense," said first author, Agneesh Barua, a PhD student at OIST. "What's interesting about venom is that it has arisen in so many different animals: jellyfish, spiders, scorpions, snakes, and even some mammals. Although these animals evolved different ways to deliver venom, an oral system - where venom is injected through a bite - is one of the most common and well-studied."

But scientists are still zeroing in on the origin of oral venom. This latest research into snakes, a group of animals renowned and feared for their potent bite, now reveals oral venom's ancient foundation.

Previously, scientists have focused on the genes that code for the proteins that make up the toxic mixture. "However, many of the toxins currently found in venom were incorporated after the oral venom system was already established. We needed to look at the genes that were present before venom's origin, genes which enabled the rise of venom systems," Barua said.

So instead, the team searched for genes that work alongside and interact strongly with the venom genes. The scientists used venom glands collected from the Taiwan habu snake - a pit viper found in Asia.

The researchers identified around 3,000 of these 'cooperating' genes and found that they played important roles in protecting the cells from stress caused by producing lots of proteins. The genes were also key in regulating protein modification and folding.

When proteins are made, the long chains of amino acids must fold together in a specific way. Just like a wrong fold when doing origami, one misstep prevents the protein from assuming the required shape needed for it to function properly. Misfolded proteins can also accumulate and damage cells.

"The role of these genes in the unfolded protein response pathway makes a lot of sense as venoms are complex mixtures of proteins. So to ensure you can manufacture all these proteins, you need a robust system in place to make sure the proteins are folded correctly so they can function effectively," explained Barua.

The researchers then looked at the genomes of other creatures across the animal kingdom, including mammals like dogs, chimpanzees and humans, and found that they contained their own versions of these genes.

When the team looked at the salivary gland tissues within mammals, they found that the genes had a similar pattern of activity to that seen in snake venom glands. The scientists therefore think that salivary glands in mammals and venom glands in snakes share an ancient functional core that has been maintained since the two lineages split hundreds of millions of years ago.

"Many scientists have intuitively believed this is true, but this is the first real solid evidence for the theory that venom glands evolved from early salivary glands," said Barua. "And while snakes then went crazy, incorporating many different toxins into their venom and increasing the number of genes involved in producing venom, mammals like shrews produce simpler venom that has a high similarity to saliva."

The apparent ease with which the function of salivary glands can be repurposed to be venomous is startling - and could mean that scientists start looking at other mammals in an unsettling new light.

"There were experiments in the 1980s that showed that male mice produce compounds in their saliva that are highly toxic when injected into rats," said Barua. "If under certain ecological conditions, mice that produce more toxic proteins in their saliva have better reproductive success, then in a few thousand years, we might encounter venomous mice."

Whether mice are or are not on this evolutionary path is a matter that requires further investigation, but it certainly blurs the line between venomous and non-venomous species.

And although very unlikely, if the right ecological conditions ever existed, humans too could become venomous. "It definitely gives a whole new meaning to a toxic person," joked Barua.

###

POSTMODERN ALCHEMY

Lab-made hexagonal diamonds stiffer than natural diamonds

WASHINGTON STATE UNIVERSITY

Research News

 

PULLMAN, Wash. -- Nature's strongest material now has some stiff competition. For the first time, researchers have hard evidence that human-made hexagonal diamonds are stiffer than the common cubic diamonds found in nature and often used in jewelry.

Named for their six-sided crystal structure, hexagonal diamonds have been found at some meteorite impact sites, and others have been made briefly in labs, but these were either too small or had too short of an existence to be measured.

Now scientists at Washington State University's Institute for Shock Physics created hexagonal diamonds large enough to measure their stiffness using sound waves. Their findings are detailed in a recent paper in Physical Review B.

"Diamond is a very unique material," said Yogendra Gupta, director of the Institute for Shock Physics and corresponding author on the study. "It is not only the strongest -- it has beautiful optical properties and a very high thermal conductivity. Now we have made the hexagonal form of diamond, produced under shock compression experiments, that is significantly stiffer and stronger than regular gem diamonds."

Researchers have long wanted to create a material stronger than natural diamonds, which could have a variety of uses in industry. While many theorized that hexagonal diamonds would be stronger, the WSU study provides the first experimental evidence that they are.

Lead author Travis Volz, now a post-doctoral researcher at Lawrence Livermore National Laboratory, focused his dissertation work at WSU on the creation of hexagonal diamonds from graphite. For this study, Volz and Gupta used gunpowder and compressed gas to propel small graphite disks about the size of a dime at a speed of around 15,000 miles per hour onto a transparent material. The impact produced shockwaves in the disks that very rapidly transformed them into hexagonal diamonds.

Immediately after impact the researchers produced a small sound wave and used lasers to measure its movement through the diamond. Sound moves faster through stiffer material. Previously sound moved fastest through cubic diamond; in the lab-created hexagonal diamonds it moved faster.

Each process happened in several billionths of a second, or nanoseconds, but the researchers were able to make the stiffness measurements before the high velocity impact destroyed the diamond.

Stiffness is the ability of a material to resist deformation under a force or pressure -- for instance, a rock is stiffer than rubber as rubber will bend when pressed. Hardness is the resistance to scratching or other surface deformations.

Generally stiffer materials are also harder, said Volz. While the researchers weren't able to scratch the diamonds to test hardness directly, by measuring the diamonds' stiffness, they can make inferences about their hardness.

If the science advances to the point where lab-made hexagonal diamonds can be created and recovered, they could have a range of uses.

"Hard materials are useful for machining capabilities," said Volz. "Diamond has been used for a long time in drill bits, for example. Since we found that the hexagonal diamond is likely harder than the cubic diamond, it could be a superior alternative for machining, drilling or any type of application where the cubic diamond is used."

While the industrial advantages are clear, Gupta said it is still possible hexagonal diamonds could one day be used on engagement rings. Currently lab-made cubic diamonds have less value compared to their natural peers, but hexagonal diamonds would likely be more novel.

"If someday we can produce them and polish them, I think they'd be more in-demand than cubic diamonds," said Gupta. "If somebody said to you, 'look, I'm going to give you the choice of two diamonds: one is lot more rare than the other one.' Which one would you pick?"

###

Decellularized spinach serves as an edible platform for laboratory-grown meat

The veiny skeleton of a spinach leaf shows for the first time it can support the growth of artificial meat, a Boston College researcher reports

BOSTON COLLEGE

Research News

 

IMAGE: THIS DIAGRAM SHOWS THE STEPS BOSTON COLLEGE AND WPI RESEARCHERS TOOK TO ISOLATE AND SEED PRIMARY BOVINE SATELLITE CELLS ON A DECELLULARIZED SPINACH LEAF SCAFFOLD. view more 

CREDIT: FOOD BIOSCIENCE

Chestnut Hill, Mass. (3/31/21) -- Spinach, a cost-efficient and environmentally friendly scaffold, provided an edible platform upon which a team of researchers led by a Boston College engineer has grown meat cells, an advance that may accelerate the development of cultured meat, according to a new report in the advance online edition of the journal Food BioScience.

Stripped of all but its veiny skeleton, the circulatory network of a spinach leaf successfully served as an edible substrate upon which the researchers grew bovine animal protein, said Boston College Professor of Engineering Glenn Gaudette, the lead author of the new study. The results may help increase the production of cellular agriculture products to meet rising demand and reduce environmental costs.

"Cellular agriculture has the potential to produce meat that replicates the structure of traditionally grown meat while minimizing the land and water requirements," said Gaudette, the inaugural chair of BC's new Engineering Department. "We demonstrate that decellularizing spinach leaves can be used as an edible scaffold to grow bovine muscle cells as they develop into meat."

Earlier advances by Gaudette in this area garnered worldwide attention. In 2017, Gaudette and a multi-university team showed that human heart tissue could be cultivated on a spinach leaf scaffold, which was chosen because it offered a natural circulatory system that is nearly impossible to replicate with available scientific tools and techniques.

"In our previous work, we demonstrated that spinach leaves could be used to create heart muscle patches," said Gaudette. "Instead of using spinach to regrow replacement human parts, this latest project demonstrates that we can use spinach to grow meat."

Gaudette said the team, which included Worcester Polytechnic Institute graduate students Jordan Jones and Alex Rebello, removed the plant cells from the spinach leaf and used the remaining vascular framework to grow isolated cow precursor meat cells. The cells remained viable for up to 14 days and differentiated into muscle mass.

"We need environmentally and ethically friendly ways to grow meat in order to feed the growing population," said Gaudette, whose research is supported by New Harvest. "We set out to see if we can use an edible scaffold to accomplish this. Muscle cells are anchorage dependent, meaning they need to grab on to something in order to grow. In the lab, we can use plastic tissue culture plates, but plastic is not edible."

The researchers point out that the successful results will lead to further characterization of the materials and scientific processes to better understand how to meet consumer demand and gauge how large-scale production could be accomplished in accordance with health and safety guidelines.

"We need to scale this up by growing more cells on the leaves to create a thicker steak," said Guadette. "In addition, we are looking at other vegetables and other animal and fish cells."

 Study contributes to our understanding of how cocaine withdrawal affects brain circuits

The results could help clinicians understand addiction and enable people to better manage substance withdrawal

WYSS CENTER FOR BIO AND NEUROENGINEERING

VIDEO: RESEARCHERS HAVE FOUND NEW EVIDENCE OF HOW COCAINE WITHDRAWAL AFFECTS BRAIN CIRCUITS. THEY PREPARED ENTIRE INTACT MOUSE BRAINS AND MADE THEM COMPLETELY TRANSPARENT BY REMOVING LIPIDS THEN IMAGED THEM WITH THE... view more 

CREDIT: WYSS CENTER FOR BIO AND NEUROENGINEERING AND UNIVERSITY OF LAUSANNE

GENEVA, LAUSANNE, 31 March 2021: Cocaine is a highly addictive substance that, in the long term, can have adverse effects on health and wellbeing. There are around 18 million cocaine users globally, according to a UN report. Understanding how cocaine modifies brain networks could reveal potential targets for therapies to treat addiction and other neuropsychological disorders.

A new study published today in the journal Frontiers in Synaptic Neuroscience by a team of researchers from the University of Lausanne and the Wyss Center for Bio and Neuroengineering reveals that during cocaine withdrawal, neurons in a brain area associated with depression connect to neurons embedded in an anti-reward system.

When we receive a reward, neurons fire in the brain's ventral tegmental area (VTA) - a region of the brain that produces dopamine. Dopamine is a chemical messenger that creates feelings of joy or pleasure. It spreads throughout the brain, motivating us to repeat our actions and achieve the feeling of pleasure again, a central facet of addictive behavior. When we miss out on a reward, or stop taking an addictive drug, the lateral habenula - a brain area linked to depression - becomes hyperactive and sends signals to the VTA that results in depressive symptoms.

What researchers did not know, until now, is exactly where the neurons from the lateral habenula extend into the VTA and what they connect to during withdrawal from cocaine. Through a series of experiments, the team discovered that, in mice, the neurons from the lateral habenula synapse mostly to neurons in the VTA that do not produce dopamine, creating a connection to an anti-reward system that may be key in driving adverse behavior.

Manuel Mameli, PhD, Associate Professor in the Department of Fundamental Neuroscience, University of Lausanne said: "We wanted to understand why individuals experience depression when they stop taking a substance like cocaine. We knew that cocaine withdrawal induces changes to brain circuits linked to depression and reward, but our results have now taken us a step further and show that there is a reorganization of brain circuits that drive negative behavior."

The team combined their expertise in sample preparation and advanced microscopy to capture 3D images of entire intact mouse brains. They used viral 'tags' to make the neurons fluoresce, then created completely transparent samples by removing lipids, before imaging with the Wyss Center's custom-built lightsheet microscope. With data analytics and visualization tools, they identified the 3D morphology of specific neurons to understand their anatomical distribution inside the brain.

Stephane Pages, PhD, Scientific Coordinator at the Wyss Center and Senior Research Associate at the University of Geneva said: "The beauty of lightsheet imaging is being able to see which neurons connect to each other in the brain. Our microscope and data analytics capabilities pinpointed the specific neuronal connections between the two major brain areas implicated in drug withdrawal."

The results of the study also show that neurons in the anti-reward circuits not only project to the VTA but also from there into other parts of the brain resulting in a cascade of 'anti-reward' information into areas responsible for decision making and motivation, amongst others. The next step is to dissect the functionality of these non-dopamine, anti-reward, circuits to better understand how they influence behavior.

Neuronal connections between the two major brain areas implicated in drug withdrawal (IMAGE)

CAPTION

Neurons from the lateral habenula (green) mostly connect to an anti-reward network of non-dopamine neurons in the VTA. Dopamine neurons are shown in purple. Although there are some connections between the green neurons from the lateral habenula and purple dopamine neurons, these are not the majority.

CREDIT

Mameli Lab, University of Lausanne

The paper: Output-specific adaptation of habenula-midbrain excitatory synapses during cocaine withdrawal by Joseph Clerke, Patricia Preston-Ferrer, Ioannis S. Zouridis, Audrey Tissot, Laura Batti, Fabian F. Voigt, Stéphane Pagès, Andrea Burgalossi and Manuel Mameli is published in Frontiers in Synaptic Neuroscience, doi 10.3389/fnsyn.2021.643138.

Image caption: Neurons from the lateral habenula (green) mostly connect to an anti-reward network of non-dopamine neurons in the VTA. Dopamine neurons are shown in purple. Although there are some connections between the green neurons from the lateral habenula and purple dopamine neurons, these are not the majority.

Image credit: Mameli Lab, University of Lausanne

About the Wyss Center for Bio and Neuroengineering, Geneva, Switzerland

The Wyss Center is an independent, non-profit research and development organization that advances our understanding of the brain to realize therapies and improve lives.

The Wyss Center staff, together with the Center's academic, clinical and industrial collaborators, pursue innovations and new approaches in neurobiology, neuroimaging and neurotechnology.

Wyss Center advances reveal unique insights into the mechanisms underlying the dynamics of the brain and the treatment of disease to accelerate the development of devices and therapies for unmet medical needs.

The Wyss Center was established by a generous donation from the Swiss entrepreneur and philanthropist Hansjörg Wyss in 2014. Additional resources from funding agencies and other sources help the Wyss Center accelerate its mission. http://www.wysscenter.ch/

The diary of a drug fiend : Crowley, Aleister, 1875-1947 ...

https://archive.org/details/b29826433

2017-10-12 · The diary of a drug fiend by Crowley, Aleister, 1875-1947. n 80057223. Publication date 1922 Topics Crowley, Aleister, 1875-1947, Substance-Related Disorders, Drug abuse, Drug addicts ... PDF download. download 1 file . SINGLE PAGE ORIGINAL JP2 TAR download. download 1 file ...

Weight loss changes people's responsiveness to food marketing: study

UNIVERSITY OF BRITISH COLUMBIA

Research News

 

Obesity rates have increased dramatically in developed countries over the past 40 years -- and many people have assumed that food marketing is at least in part to blame. But are people with obesity really more susceptible to food marketing? And if they are, is that a permanent predisposition, or can it change over time?

According to a new study by UBC Sauder School of Business Assistant Professor Dr. Yann Cornil (he/him/his) and French researchers, people with obesity do tend to be more responsive to food marketing -- but when their weight drops significantly, so does their responsiveness to marketing.

For the study, which was published in the Journal of Consumer Psychology, the researchers followed three groups: patients with severe obesity before they had gastric bypass or other weight-loss surgeries (collectively known as bariatric surgery), as well as three and 12 months after; people with obesity who were not undergoing bariatric surgery; and people who were not obese.

To measure their responsiveness to food marketing, the researchers evaluated what's called framing effects -- that is, how branding, advertising, and labeling "frame," and thus influence food evaluations and choices. In one study, participants were asked to estimate the calorie content in well-known snacks and drinks including some, which marketers typically framed as healthy (i.e. apple juice, granola bars), and others, which are not framed as healthy (i.e. soft drinks, chocolate bars).

The researchers found that everyone underestimated the calorie content of snacks that were framed as healthy but the effect was more pronounced in people with obesity.

To further test the framing effect, the researchers had participants hypothetically choose a portion of french fries from a fast food restaurant, and gave them the nutritional information they would need to make an informed decision. The three options were always the same in quantity -- 71g, 117g, and 154g -- but in one instance they were labeled small, medium and large, and in another instance the same portions were labeled mini, small and medium: a marketing tactic aimed at making larger portions seem more reasonable.

"We measured how likely people were sensitive to that framing, and whether it would change their choice of fries quantity depending on how the portions are labeled," explains Dr. Cornil, who says the people with obesity were more likely to follow the labeling and not the actual information about quantity -- so they would choose the portion labeled "medium" even though that's quite large.

Overall the researchers, who worked closely with the Pitié-Salpêtrière Hospital in Paris, found that the people with obesity tended to be more responsive to food marketing -- but when they lost a significant amount of weight because of bariatric surgery, their level of responsiveness to food marketing dropped substantially.

"People with obesity going through bariatric surgery will become less responsive to marketing over time," says Dr. Cornil. "And after 12 months, their responsiveness to marketing reaches the level of people with more medically-recommended weight."

Dr. Cornil says it's not clear whether people with obesity become less responsive to marketing because of physiological changes following the surgery -- hormonal, neurological shifts or changes to the gut microbiota -- or because of people's desire to change their lifestyles and habits. Another possible reason, he adds, is that people's tastes tend to shift following bariatric surgery.

"The results clearly suggest a bidirectional influence between people's weight status, psychology and responsiveness to the environment -- including marketing," says Dr. Cornil. "So, it's a complex relationship."

However, had the researchers found the responsiveness to marketing remained high even after weight loss, it would have pointed to a deeper-rooted predisposition.

"That would mean people are endowed with unchangeable psychological characteristics that would always make them more responsive to marketing -- which would make it very difficult to sustain a medically-recommended weight," he explains. "But one of the positive things is that after significant weight loss, people become less responsive to marketing, such that it is more sustainable to remain at a lower body mass index."

Dr. Cornil says the findings are especially important because for years, researchers have assumed that marketing messages -- especially for foods that are high-calorie and low in nutrition -- are at least partly responsible for the obesity epidemic, but there wasn't clear empirical evidence.

"Our results provide important insights for policy-makers in charge of regulating food marketing in order to curb obesity," says Dr. Cornil.

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Unique macro-vertebrate at risk from blood sport and climate change

OKINAWA INSTITUTE OF SCIENCE AND TECHNOLOGY (OIST) GRADUATE UNIVERSITY

Research News

 

IMAGE: AN ARTISTIC DEPICTION OF A KANGASKHAN - A TWO-METER-TALL POKÉMON ENDEMIC TO AUSTRALIA. view more 

CREDIT: IMAGE BY KATERINA ZAPFE

• The kangaskhan, Australia's only species of endemic Pokemon in Pokemon Go, is commonly poached within its natural habitat by Pokemon trainers for use in fighting contests

• Researchers used several species distribution modeling algorithms to predict how climate change, on top of the already existing human-induced pressures, would impact the distribution of the kangaskhan in the future

• In addition to this, they found a way to measure how biased commonly used species distribution models are, and found that some models are so biased that their results weren't influenced by the data at all

• The researchers compared these results to previously published models for hundreds of species of Australian mammals and found similar biases

• This research has highlighted specific problems with common species distribution models, and has given scientists new statistical tools to refine them in the future

Kangaskhan (Garura kangaskhani) are two-meter-tall Pokemon, endemic to Australia. Although commonly spotted around cities and other urban areas, information is lacking about their basic biology and wider range distribution. Much of what is known is based on anecdotes from the public, especially unlicensed breeders, many of whom are not trained in scientific research. Today, kangaskhan are believed to be threatened due to frequent poaching of adults and eggs. The poaching is primarily motivated by the demand for these animals to be used in fighting contests. This pressure, combined with the fact that climate change is predicted to have a large impact in Australia over the next few decades, has resulted in a bleak outlook for this majestic Pokemon species.

Now, researchers in the Biodiversity and Biocomplexity Unit at the Okinawa Institute of Science and Technology Graduate University (OIST) have taken an extensive look at how climate change will impact the existence of suitable habitat for kangaskhan. This study was published today in Methods in Ecology and Evolution.

"Apart from seeming to prefer partly cloudy weather, very little is known about the species' climatic preferences," said lead author Dr. Dan Warren, who previously worked as a researcher in Australia. "This makes it difficult to estimate the response of kangaskhan to environmental change, or how climate change might combine with the effects of poaching to impact the species' long-term survival. For this research, we used several well-known modeling methods to gain insight into how threatened kangaskhan really are."

With data that was initially recorded by hobbyists and professional trainers seeking out kangaskhan for exploitation, the researchers attempted to shed light on what the future holds for this species. Species distribution models were the obvious way to go. These models are a common way for scientists to predict changes in the availability of suitable habitat for a species, in response to estimated shifts in environmental parameters like rainfall, humidity, temperature, and vegetation cover.

In terms of the results, the models differed on what they predicted the future to be for the kangaskhan depending on the algorithms used. Three of the models predicted a decrease in habitat suitability, though differed substantially on the magnitude of this decline. Two other models switched their answer depending on the climate estimates used, and a sixth model predicted an increase in suitability of habitat. Policymakers and stakeholders should take this uncertainty into account and err on the side of caution when it comes to safeguarding the future of kangaskhan.

Aside from revealing uncertainty surrounding the long-term survival of kangaskhan, the research has also shed light on how scientists can calculate the biases that come with species distribution models. Every one of these models comes with a level of bias and uncertainty, depending on the choices made in the modeling process. For example, when predicting the implications of climate change, the amount of future CO2 emissions needs to be considered, and yet estimating this can be tricky as it's based on human behavior. Differences in these estimates can interact with other aspects of the modeling process, resulting in biases in predictions of how climate change will affect threatened and endangered species. Scientists know about these biases but have never found a way to measure them before, until now.

"We found that we could determine the level of bias with a simple statistical test," said Dr. Warren. "And, in doing so, we realized that some of these models could be so biased that the data didn't have much effect on their results... effectively the conclusion was picked based on study design regardless of what the data actually showed," said Dr. Warren.

In addition to the kangaskhan, the researchers demonstrated similar biases for these models by reexamining a previous study that built models for 220 species of Australian mammals, as well as a study that simulated artificial organisms in order to understand how well models estimated species' environmental tolerances. The researchers hope that by revealing these biases they are providing a more secure future for kangaskhan and the rest of the world's biodiversity.

Dr. Warren emphasized that although the study itself might seem strange, what it's revealed will actually go on to help other researchers create more robust estimates of species distribution. His primary reason for choosing to do this research on a Pokemon character was to engage a broader audience with issues that conservation scientists regularly need to think about.

"It's a bit silly but it's also cool science," said Dr. Warren. "Stakeholders use these models for predicting a number of important ecological phenomena, from the effects of climate change, to the dispersal of diseases and invasive species, so having a firm understanding of the biases the models might have is important. We've just scratched the surface of what we can do with this method so I think this could be a useful tool for a whole bunch of things."

His final point was a word of caution with respect to the culture that surrounds Pokemon. "It's specifically based around over-exploitation with the tagline 'gotta catch them all.' The rarer they get, the more valuable they get. This is like some of the larger tuna species, which are in serious danger of going extinct. We might have focused on climate change in this study but, for many Pokemon (and many species around the world), overexploitation should also be a concern."

APRIL FOOLS