In the study published on December 17, 2021, in Neuron, the Salk group focused on a group of neurons in the brainstem called the lateral parabrachial nucleus, which is arranged in a core-shell configuration. They found that neurons in the core project to the amygdala, an area of the brain that processes fear and the emotional experience of pain. Neurons in the shell project to the pre-Bötzinger complex, a region that generates breathing rhythm. The core and shell neurons influence each other according to inputs from these areas, making us breathe faster when we experience pain or anxiety.

“We are the first group to demonstrate how the lateral parabrachial nucleus coordinates breathing and pain,” says the paper’s senior author, Sung Han, assistant professor in Salk’s Clayton Foundation Laboratories for Peptide Biology. “By understanding the circuits in this brain region, we may be able to tease apart breathing regulation and pain regulation to develop a medication that inhibits feelings of pain without repressing breathing, like OIRD.”

In OIRD, opioids repress breathing as well as pain; it is the major cause of death from opioids. In previous work,Han’s lab showed that opiates like morphine repress breathing by triggering specific receptors, called mu opioid receptors (MOR), leading to the inhibition of neurons that express them. They also showed that reactivating the cells that express MOR can reverse OIRD. The current work suggests additional approaches for preventing OIRD, possibly by inhibiting neurons in the region’s core (blunting fear/anxiety) while exciting similar neurons in the shell (supporting breathing).

To show how these neurons coordinate breathing with pain and emotions, the researchers first used light and chemical agents to prove that manipulating the MOR-expressing neurons in the lateral parabrachial nucleus alters breathing rate in mice. They then used fluorescent tracers to map the inputs and outputs to the MOR-expressing neurons. Their results indicated that neurons clustered in the core of the region project to the central amygdala, while neurons clustered in the surrounding shell project to the pre-Bötzinger complex. Electrophysiological recordings of one population while stimulating the other population revealed that some of those subpopulations are reciprocally connected, with an excitatory network between them. Via this network, signals of fear and pain were coordinated with breathing rhythms.

“We have found very intricate circuits involving upstream and downstream input to these neurons. By uncovering this circuit mechanism, we can better explain why breathing can often be coordinated with pain and anxiety,” says first author Shijia Liu, a graduate student in Han’s lab.

Han is eager to see the team’s discovery have a translational application. “The biggest problem these days is that opioids reduce pain but also reduce breathing, so people die,” says Han, holder of the Pioneer Fund Development Chair. “By understanding those two mechanisms in our research, maybe we can manipulate certain populations of neurons by pharmacological intervention so that we can control pain without changing the breathing.”

Han’s group is currently working on genetic analyses of the core and shell population to identify functional markers that specifically regulate pain or breathing.

Other authors on the study are Mao Ye, Gerald M. Pao, Jinho Jhang, Jonghyun Kim, Sukjae Joshua Kang, Dong-Il Kim of Salk; and Samuel Myeongsup Song and Haibei Jiang of the University of California San Diego.

The research was supported by the National Institute of Mental Health, the Brain Research Foundation, the Mary K. Chapman Foundation, the Jesse & Caryl Philips Foundation, the National Institutes of Health-National Cancer Institute and the Waitt Foundation.

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The multiyear effort was conducted by researchers at University of California, Davis; Johns Hopkins University; University of Connecticut; and Northern Arizona University; and was funded by Save the Redwoods League. The research provides the foundation to better understand redwood responses to climate impacts and pathogens.

The research team previously made available the completed giant sequoia genome research in November 2020.

“It’s remarkable how far genomics research has come since we undertook this challenge in 2017,” said David Neale, plant sciences professor emeritus at UC Davis and lead author on the new coast redwood genome research. “Our work on the coast redwood and giant sequoia genomes will enable us to develop modern genetic tools that can be used in the restoration and conservation of these ecologically important tree species.”

The league and its research partners launched the Redwood Genome project in 2017. Project partners outlined an ambitious plan to fully sequence the coast redwood and giant sequoia genomes for the first time using new conifer genetic sequencing techniques.

The genomic resources and screening tools developed in this project will help researchers quickly assess evolutionary adaptive potential in these forests and ultimately inform forest restoration and management plans.

The coast redwood genome

The coast redwood is the world’s tallest tree, and its genome is among the most complex sequenced. Nearly nine times larger than the human genome, it is also the second largest genome sequenced. The redwood genome has 26.5 billion base pairs of DNA, and it is hexaploid, meaning redwoods have six sets of chromosomes. Humans have 3 billion base pairs of DNA and are diploid, with two sets of chromosomes.

When comparing the coast redwood genome sequence to that of other conifers, researchers found hundreds of gene families unique to the coast redwood. Many are genes that help the trees respond to and fight stress, resist disease and repair after injury.

The giant sequoia genome

The giant sequoia is the world’s largest tree species and among the oldest on the planet. As reported by the research team in 2020, its genome contains 8.125 billion base pairs of DNA. Similar to the human genome, the giant sequoia genome is diploid. The reference genome produced for this study represents the first genome sequenced in the Cupressaceae family, and it lays a foundation for using genomic tools to aid in giant sequoia conservation and management.

The genomes of conifers are three to 10 times larger than the human genome. They are highly repetitive and complex. The first conifer genomes ever sequenced were the Norway spruce in 2013 and loblolly pine in 2014, 10 years after the human genome was completed.

Sequencing conifer genomes was not previously feasible due to economic and technical limitations. With technological advancements that also reduced the cost, 10 conifer genomes have now been sequenced.

About the Redwood Genome Project

In the last 160 years, commercial logging and clear-cutting claimed 95% of the coast redwood range and about one-third of the giant sequoia range. In 2020, an estimated 10%-14% of giant sequoia died from high-intensity wildfires, and in some areas the seedbank also died.

Two wildfires also burned through large sections of the giant sequoia range in 2021, and mortality from those is currently estimated to impact another 5% of the mature trees. As a result, both forests have experienced significant losses in total acreage and genetic diversity.

With these significant impacts to both populations, the league is leading restoration projects in both forest ranges. It aims to use this and future genetic research to inform efforts to restore and maintain genetic diversity and bolster the resilience of these species in the face of rapid, unprecedented environmental change.

“This ambitious scientific research provides a critical foundation for the League and the entire redwoods community,” said Joanna Nelson, Ph.D., director of science and conservation planning for Save the Redwoods League. “It will ultimately help us understand the incredible range of responses that coast redwood and giant sequoia species have exhibited in the face of climate change and how native genetic diversity has informed these responses. The Redwood Genome Project helps us see, for the first time, the full genetic diversity that has allowed these forests to adapt and survive for millennia — and could protect them against a suite of conditions they have never experienced.”

The study was supported by grants from National Science Foundation, USDA, and National Institutes of Health. Save the Redwoods League donors contributed over $1 million to the Redwood Genome Project through Forever Forest: The Campaign for the Redwoods, including a significant lead gift from Ralph Eschenbach and Carol Joy Provan. Genomic services companies Illumina, Oxford Nanopore Technologies and Dovetail Genomics contributed in-kind.

But the relationship between fire and ice, in terms of Earth’s climate, is not quite as “either or” as Frost depicted. In the case of a study presented today at the 2021 AGU Fall Meeting in New Orleans, that relationship is more “give and take.”

The team of researchers behind the recent study describe a link between dwindling sea ice and worsening wildfires in the western United States. As sea ice melts from July to October, sunlight warms the increasingly iceless, surrounding area. This ultimately brings heat and fire-favorable conditions to distant states like California, Washington, and Oregon later in autumn and early winter.

The researchers describe this relationship — its existence previously known, but its underlying mechanism now described for the first time — as similarly influential as climate patterns like the El Niño-Southern Oscillation.

“It’s not a perfect analogy, but teleconnections like this are a bit like the butterfly effect,” said Hailong Wang, an Earth scientist at the Department of Energy’s Pacific Northwest National Laboratory and coauthor of the new study. He references the popular feature of chaos theory where a butterfly’s flapping wings are thought to influence the formation of a distant tornado.

“Climate conditions in one part of the world can, over time, influence climate outcomes from thousands of kilometers away,” said Wang. “In our case, we find the Arctic region and the western United States are connected by this relationship. Regional land and sea surface warming caused by sea ice loss distantly triggers hotter and drier conditions in the West later in the year.”

Wang presented his findings virtually at an AGU press conference that explored wildfire in a changing climate on Dec. 16.

A tale of two vortices

Wang and his fellow authors found that, as Arctic sea ice melts and the surrounding land and sea surfaces warm, a vortex strengthens in the atmosphere above the heated area. This vortex, spinning counterclockwise like a cyclone, is spawned by differences in air pressure.

The powerful vortex constantly pushes the polar jet stream out of its typical pattern, diverting moist air away from the western United States. With the now wavier jet stream nudged off its usual course, a second vortex, spinning clockwise, forms under the ridge of the polar jet above the western United States. This second vortex — similar to the vortex responsible for the Pacific Northwest’s extreme heat earlier this summer — brings with it clear skies, dry conditions and other fire-favorable weather.

As the Arctic continues warming, it can sharpen the contrast between these two distantly connected systems, further exacerbating conditions in an already fire-ravaged region. More than three million acres have burned across California alone during the 2021 wildfire season.

“This dynamics-driven connection warms and dries out the western United States region,” said Yufei Zou, lead author and data scientist who was a postdoc at PNNL when the study was conducted. “By uncovering the mechanism behind that teleconnection, we hope those in charge of managing forests and preparing for wildfires will be more informed.”

Less ice, more heat

To probe the influence of Arctic sea ice in forming fire-favorable climate conditions, the study’s authors called upon the past four decades of recorded sea ice levels. The team isolated the mechanism at play through modeling conducted at the National Energy Research Scientific Computing Center, a DOE Office of Science user facility at Lawrence Berkeley National Laboratory.

Arctic sea ice has continually declined since scientists began measuring its loss in the late 1970s. End-of-summer sea ice cover has diminished by 13 percent each decade relative to the 1981-2010 average, according to the National Oceanic and Atmospheric Administration.

Arctic sea ice is projected to continue declining, eventually leading to periods of iceless Arctic waters before the 2050s. Today, even the older, thicker ice that persists year-round is now thinner and more fragile.

In addition to Wang and Zou, authors from PNNL include Philip J. Rasch and Rudong Zhang.

The new research on these unique soils, being presented on Wednesday, 15 December at AGU Fall Meeting 2021, marks the first attempt to quantify carbon capture by canopy soils. The work highlights another way old-growth forests are rich, complex ecosystems that cannot be quickly replaced by replanting forests.

Tree branches collect fallen tree leaves and other organic material over hundreds of years, like the ground does. On top of the branches, the plant litter decomposes as it accumulates, forming a carbon-rich layer that can be several inches thick. The researchers climbed up into the rainforest canopy in Costa Rica, instruments in hand, to find out just how much carbon canopy soils can contain.

Active carbon, a short-term storage pool of organic carbon, was three times higher in canopy soil compared to soils underfoot, the researchers found.

“We knew these would be really organic-rich soils, but we didn’t expect the extremely large amount of carbon compared to mineral soils,” said Hannah Connuck, an undergraduate researcher at Franklin and Marshall College who will be presenting the study results.

The researchers are still calculating the total concentration of organic carbon at their research site, but other research has found canopy soils to have up to 10 times higher concentrations of organic carbon, according to soil scientist Peyton Smith, a study co-author and Connuck’s soil science mentor at Texas A&M University.

Connuck and Smith also measured how much carbon dioxide was being released by microbial organisms living in the canopy soils, which is critical for knowing whether soils are storing or releasing carbon overall. They found that even though the microbes were releasing higher volumes of carbon dioxide than ground soils, their rate of carbon storage was rapid enough to compensate, likely making canopy soils a net carbon sink that has not been considered in carbon models yet.

“It could be a substantial carbon sink, and we need to account for it,” Smith said.

Like other soils, canopy soils take a long time to form, and therefore take a long time for a forest to recover if an area of old growth is cut down. The soils also host unique microbiomes, including highly diverse microbial organisms and canopy-specific plants like epiphytic orchids.

“It’s a good argument for keeping primary and other old-growth forests around, rather than harvesting and replanting with secondary growth forests,” Connuck said.

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To conserve these species, scientists must first know where they are. While the distributions of some plant and animal groups have been extensively mapped, comparatively little is known regarding the whereabouts of the world’s insects.

In a new study, researchers created the most detailed distribution map to date of butterflies in the American tropics, showing that areas of highest diversity coincide with regions most threatened by deforestation and development. The study specifically focused on Ithomiini, or glasswing butterflies, a large group with nearly 400 species that occur throughout much of Central and South America. Their ubiquity may make them a good indicator for the fate of other insects in the region.

“If we want to understand the diversity of insects in general, then one approach is to concentrate on groups that likely reflect the diversity of all insects and for which we have good knowledge, like butterflies,” said study co-author Keith Willmott, curator and director of the Florida Museum of Natural History’s McGuire Center for Lepidoptera and Biodiversity.

Mimicry both helps and hinders glasswings

Glasswing butterflies get their namesake from their unusual, transparent wings marked with colorful spots of alternating hues and patterns. As with many other butterfly species, such as monarchs, these markings serve as a warning. Male glasswing butterflies feed on the nectar and tissue of poisonous plants, concentrating the toxins in their abdomen and passing them on to females when mating. These toxins, a type of alkaloid, give the butterflies and their eggs a bitter taste that makes them unpalatable.

But would-be predators aren’t born innately knowing not to eat these butterflies, instead learning through trial and error. As a result, many glasswing species have evolved similar wing patterns that give them strength in numbers.

“Since different species share the same warning color patterns, they share the overall cost per species of educating predators to avoid them,” Willmott said.

This type of resemblance, called Müllerian mimicry, has helped glasswing butterflies survive and diversify in the varied habitats of the tropics, but it also comes at a cost. While this strategy is effective when all species resembling one another are thriving, the extinction of any one species could jeopardize the survival of others, Willmott explained. “This is particularly true if one of the more common species goes extinct, because all the others lose the benefit they gained from being involved in Müllerian mimicry with those butterflies.”

Glasswing butterflies are most diverse and most vulnerable at high elevations

Willmott and his colleagues have spent the last several decades trekking across mountains and forests in search of glasswings, describing new species and documenting their natural history along the way. By combining the data they’ve collected over the years with information gleaned from specimens in more than 60 museums and private collections, the researchers compiled nearly 30,000 distribution records. They used this extensive dataset to map the diversity of glasswings and the interactions between lookalike species throughout the American tropics.

Their results indicate glasswings are highly diverse in particular parts of their range, including the Amazon River basin, where their transparent wings help them blend in against the backdrop of forest gloom. But the majority of species cluster together in mountainous biodiversity hotspots. The eastern slopes of the Andes Mountains contained the top 5% of glasswing diversity, while secondary hotspots included the highlands of Central America and the Atlantic coastal forest of Brazil.

While large tracts of the Amazon rainforest remain relatively undisturbed, glasswing diversity in the tropical Andes frequently overlapped with areas at the highest risk of habitat loss due to land conversion for agriculture. This was especially true for species with restricted distributions, highlighting the pressing need for conservation efforts in these areas.

Mountainous regions create a variety of small, localized environments as they climb in elevation. The relatively young Andes, which are among the world’s highest mountains, support a correspondingly large number of species. The differences in topography, temperature and rainfall also make the Andes an ideal place to grow a variety of crops. “At the moment, loss of habitat is the most significant threat,” Willmott said. “It is just an unfortunate coincidence that areas that are good for people to live are also areas that support high animal and plant diversity.”

Lead author Maël Doré, a doctoral student at the National Museum of Natural History in Paris, also worries that climate change may further limit the range of already restricted species on the slopes of tropical mountains. As temperatures increase, species may cope by shifting their distributions to higher elevations, but whether glasswing communities will move fast enough to keep up with climate change is uncertain.

Far from the Andes, the lower and older mountains along the Brazilian Atlantic coast are home to a number of rare and endemic glasswing species, which also face threats from habitat destruction. “This region has experienced almost five centuries of human occupation, but it was also here that pioneering initiatives to protect Neotropical butterflies and their habitats were born almost 100 years ago,” said co-author André Freitas, a professor at the Universidade de Campinas in São Paulo, Brazil.

Still, Willmott and his colleagues remain optimistic. With a detailed map of where butterflies occur, conservation efforts can be directed to preserve environments and communities under threat, as well as those that are still untouched by humans.

“With more accurate maps of butterfly distributions, we can identify species and communities that currently lack protection, to more effectively focus limited resources where they are most needed,” Willmott said.