Research Highlights

As boreal forest wildfires increase in severity and frequency, new patterns of post-fire recovery are emerging. Research led by Jill Johnstone and colleagues at the U.S. National Science Foundation-supported Bonanza Creek Long-term Ecological Research site found that recent wildfires led to changes in tree species dominance that are persisting through post-fire succession in Alaska's boreal forests.

Boreal black spruce forests have historically been sustained by past fire cycles, but early recovery trends from more recent fires suggest that these forests may shift to deciduous or mixed tree species.

Because Alaskan black spruce forests interact with climate in several ways, shifts in tree species could have local and global implications, including changes to carbon and nutrient cycling, fire behavior, permafrost stability, and net ecosystem carbon balance, and thus have the potential to either warm or cool the atmosphere. However, to accurately model the direction and magnitude of the effect of future shifts on climate, scientists need better predictions of where these changes will occur.

To assess whether initial conditions can be used to predict long-term trajectories and to better understand the drivers behind change, Johnstone tracked post-fire succession across 89 boreal forest sites for a span of 13 years following a widespread fire season in interior Alaska.

Recovery patterns observed two years after fires were the strongest predictors of canopy dominance 13 years later. Fire severity interacted with environmental conditions and allowed deciduous tree seedlings, such as aspen and birch, to successfully establish and outgrow black spruce seedlings.

The researchers published their results in Ecosphere.

Read the full story from Phys.org here.

Microplastic fiber pollution in the ocean impacts larval lobsters at each stage of their development, according to new research. A study published in the Marine Pollution Bulletin reports that the fibers affect the animals' feeding and respiration, and they could even prevent some larvae from reaching adulthood.

"In today's ocean, organisms are exposed to so many environmental factors that affect how many make it to the next stage of life," said Paty Matrai, a study author and senior research scientist at Bigelow Laboratory for Ocean Sciences. "Lobsters play a fundamental role in the Gulf of Maine ecosystem as well as the state's economy, and it is important that we understand how pollutants impact their development."

Young lobsters grow to adulthood through four distinct developmental stages, and the researchers found that the physiology of each stage determined how the animals interacted with plastic fibers. The youngest lobsters didn't consume them - but they were plagued by fibers accumulating under the shells that protect their gills. In experiments where the larvae were exposed to high levels of fibers, the youngest larvae were the least likely to survive.

More mobile and agile, the older lobster larvae did not accumulate fibers under their shells - but they did ingest the particles and keep them in their digestive systems. This could be problematic for lobster larvae coming of age in the ocean. Fresh plastics often leach chemicals, and their surfaces can foster potentially toxic sea life.

Read the full story from EurekAlert! here.

Modern humans arrived in the westernmost part of Europe 41,000 – 38,000 years ago, about 5,000 years earlier than previously known, according to Jonathan Haws, Ph.D., professor and chair of the Department of Anthropology at the University of Louisville, and an international team of researchers. The team has revealed the discovery of stone tools used by modern humans dated to the earlier time period in a report published this week in the journal Proceedings of the National Academy of Sciences.

The tools, discovered in a cave named Lapa do Picareiro, located near the Atlantic coast of central Portugal, link the site with similar finds from across Eurasia to the Russian plain. The discovery supports a rapid westward dispersal of modern humans across Eurasia within a few thousand years of their first appearance in southeastern Europe. The tools document the presence of modern humans in westernmost Europe at a time when Neanderthals previously were thought to be present in the region. The finding has important ramifications for understanding the possible interaction between the two human groups and the ultimate disappearance of the Neanderthals.

“The question whether the last surviving Neanderthals in Europe have been replaced or assimilated by incoming modern humans is a long-standing, unsolved issue in paleoanthropology,” said Lukas Friedl, an anthropologist at the University of West Bohemia in Pilsen, Czech Republic, and project co-leader. “The early dates for Aurignacian stone tools at Picareiro likely rule out the possibility that modern humans arrived into the land long devoid of Neanderthals, and that by itself is exciting.”

Read the full story from University of Louisville here.

Scientists have linked sea urchins, otters and climate change to the destruction of reefs in the Aleutian Islands in a new study published in Science. Uncontrolled by sea otters, their natural predator, sea urchins are devouring the massive limestone reefs surrounding the Aleutian Islands — a process exacerbated by climate-driven changes in the marine environment, according to the study.

Brenda Konar, a University of Alaska Fairbanks professor at the College of Fisheries and Ocean Sciences and a co-author of the study, began diving in the Aleutians in the 1990s, just as the Aleutian sea otter population began to crash from killer whale predation. With otters gone, the urchin population boomed both in body size and density. They began eating more kelp, which grows on the reefs.

“In the past, there would be huge, vast kelp forests that went on for miles,” Konar said. “Now there are carpets of sea urchins everywhere — some places easily have 400 urchins per square meter. Kelp forests are essentially gone in the central and western Aleutians.” The Aleutian reefs and their kelp beds serve as nursery grounds for cod and other fish. The 1,200-mile archipelago helps support the annual multibillion-dollar Bristol Bay and Bering Sea fisheries.

Read the full story form University of Alaska Fairbanks here.

University of Montana scientists examined where high-severity wildfires – combined with hot, dry conditions following fire – are likely to cause shifts from ponderosa pine and Douglas-fir forests to different types of vegetation across the species’ range from Montana to New Mexico. They predict 16% of ponderosa pine and 10% of Douglas-fir forests in the Rocky Mountains could be lost by roughly 2050 due to the combination of high-severity fire and climate change. Their new study, “Fire-catalyzed Vegetation Shifts in Ponderosa Pine and Douglas-fir Forests of the Western United States,” was published Sept. 18 in the academic journal Environmental Research Letters.

“Forests in the West are increasingly affected by wildfire and climate change, and there is concern that this combination may lead to the loss of forests,” said Kimberley Davis, a research scientist in UM’s W.A. Franke College of Forestry and Conservation and the study’s lead author. “Forests may not return after wildfires if two things occur. First, there needs to be a high severity fire that kills adult trees. Second, there needs to be a failure of tree regeneration following the fire.”

If this combination occurs, and trees don’t regenerate, land cover will shift from ponderosa pine and Douglas-fir forests to shrubland, grassland or other forest types. To predict where such shifts are most likely, the authors compared projections of areas most likely to burn at high severity with projections of where the climate may be too hot and dry for trees to regenerate after fires.

“We know that ponderosa pine and Douglas-fir regeneration after wildfires is sensitive to seasonal climate conditions and that conditions are already too hot and dry for regeneration at some of our study sites,” Davis said. “We did not know how widespread these limiting climate conditions were and how that may change in the future.”

The researchers found that the area that can support tree regeneration has declined significantly since the 1980s, and they expect that trend to continue in the near-term future.

Read the full story from University of Montana here.

New research has shed light on how paddy field rice farming rapidly expanded along Asia’s coastline 2,000–3,000 years ago after freshwater conditions improved, according to an international team of earth sciences researchers that includes a University of Hawaiʻi at Mānoa archaeology professor. The findings were featured in an article in Proceedings of the National Academy of Science.

“Rice is the foundation of Asian civilizations, and our study reveals a remarkable relationship involving late Holocene coastal evolution and the rise of rice agriculture across coastal Asia,” said Professor Barry V. Rolett in the College of Social Sciences. “This model helps explain ancient DNA evidence suggesting a major Bronze Age demographic expansion of rice farmers of northern East Asian descent.”

Although rice history is well documented in the lower Yangtze homeland area, the early southward expansion of paddy rice farming was poorly known. The study investigated the process using a compilation of paleoenvironmental proxies from coastal sediment cores from Southeast China to Thailand and other areas of Southeast Asia.

Rolett explained that the emergence of coastal plains under enhanced freshwater conditions created expansive areas suitable for rice. As a result, over the past three millennia, the extent of coastal land suitable for wetland rice cultivation grew from about 16,000 to 96,000 square kilometers, or 9,941 to 59,651 square miles.

Read the full story from University of Hawi’i here.

University of Alabama at Birmingham researchers, led by Shahid Mukhtar, Ph.D., associate professor of biology in the UAB College of Arts and Sciences, have now built an interactome that includes the lung-epithelial cell host interactome integrated with a SARS-CoV-2 interactome. Applying network biology analysis tools to this human/SARS-CoV-2 interactome has revealed potential molecular mechanisms of pathogenesis for SARS-CoV-2, the virus responsible for the COVID-19 pandemic. The UAB research, published in the journal iScience, identified 33 high-value SARS-CoV-2 therapeutic targets, which are possibly involved in viral entry, proliferation and survival to establish infection and facilitate disease progression. These molecular insights may foster effective therapies, using combinations of existing drugs, for patients with COVID-19.

So far in 2019, the SARS-CoV-2 virus has killed nearly 1 million people worldwide and 200,000 in the United States.

The UAB researchers took many steps to generate the Calu-3-specific human-SARS-CoV-2 interactome, or CSI, that was the starting point for their network biology analyses.

They began from a comprehensive human interactome of experimentally validated protein-protein interactions, posted online in 2015, and then manually curated other protein-protein interactions from four subsequent interactome studies. The resulting human interactome contained 18,906 nodes and 444,633 “edges” — the term for the links between protein nodes.

Read the full story from University of Alabama at Birmingham here.

After nearly 15 years on an upward trend, awareness among Americans about high blood pressure and how to control and treat it is now on the decline, according to a new study. Even with the help of blood pressure medications, some groups, including older adults, are less likely than they were in earlier years to adequately control their blood pressure, the research found.

The study, funded by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health, appears online on Sept. 9 in JAMA. The authors say the trend could make longstanding efforts to fight heart disease and stroke—leading causes of death in the United States—even more challenging. High blood pressure, also called hypertension, is a major risk factor for heart disease. According to the Centers for Disease Control and Prevention (CDC), nearly 108 million Americans have hypertension, with a blood pressure reading of 130/80 millimeters of mercury (mm Hg) or higher or are taking medication for their blood pressure, but only 27 million are considered to have their blood pressure under control, despite it being a condition that can be managed.

“Reversing this decline is important because we don’t want to lose public health achievements built over prior decades,” said Lawrence Fine, M.D., chief of the Clinical Applications and Prevention Branch at NHLBI and a study co-author. “It is a challenge for the scientific community to investigate the causes of this unexpected downward trend, but developing more effective strategies to reverse and substantially improve blood pressure control is critical for the health of many Americans.”

The study included 18,262 U.S. adults age 18 and older, with high blood pressure. The definition of hypertension at the time of the study was defined by a blood pressure reading of 140/90 mm Hg or higher or by treating the condition with blood pressure medications. Participants with a blood pressure reading of less than 140/90 mm Hg were categorized as having controlled blood pressure.

With data from the National Health and Nutrition Examination Survey (NHANES) taken between1999 and 2018, the study authors looked at 20-year trends in high blood pressure awareness and treatment and blood pressure control. The CDC’s National Center for Health Statistics conducts NHANES.

Read the full news release from NIH here.

Dr. Bill Groutas, Wichita State University medical chemist, along with Kansas State University virologists Yunjeong Kim and Kyeong-Ok (KC) Chang published the study showing a possible therapeutic treatment for COVID-19 titled 3C-like protease inhibitors block SARS-CoV-2 replication in vitro and increase survival in MERS-CoV-infected mice which appears in the Aug. 3 issue of the prestigious medical journal Science Translational Medicine.

It reveals how small molecule protease inhibitors show potency against human coronaviruses. These coronavirus 3C-like proteases, known as 3CLpro, are strong therapeutic targets because they play vital roles in coronavirus replication.

The study demonstrates that this series of optimized coronavirus 3CLpro inhibitors blocked replication of the human coronaviruses MERS-CoV and SARS-CoV-2 in cultured cells and in a mouse model for MERS. These findings suggest that this series of compounds should be investigated further as a potential therapeutic for human coronavirus infection.

Read full story from WSU here.

There are many unanswered questions about COVID-19. A Kansas State University infectious disease scientist and collaborators are offering a possible research road map to find the answers.

Jürgen A. Richt, the Regents distinguished professor at Kansas State University in the College of Veterinary Medicine, has co-authored a critical needs assessment for coronavirus-related research in companion animals and livestock. The article, "A Critical Needs Assessment for Research in Companion Animals and Livestock Following the Pandemic of COVID-19 in Humans," appears in the journal Vector-Borne and Zoonotic Diseases. Co-authors include Tracey McNamara from Western University of Health Sciences and Larry Glickman from Purdue University.

Because of the rapid change of knowledge related to coronavirus, Richt and his collaborators wrote the article to stress importance of studying the ways that COVID-19 could spread between humans and animals. The scientists say that research should focus in several areas, including:

• The potential for companion animals, such as cats and dogs, to carry the virus.
• The economic and food security effects if the virus can spread among livestock and poultry.
• National security areas, especially among service animals such as dogs that detect narcotics or explosives because COVID-19 is known to affect smell and cause hyposmia or anosmia.

Richt's own coronavirus research at the Biosecurity Research Institute focuses on four areas: animal susceptibility and transmission of SARS-CoV-2, therapeutic treatments, diagnostics and vaccines. Richt develops models to test therapies and has collaborated with researchers nationally and internationally. He also is collaborating to test and develop potential vaccines that are safer and do not lead to vaccine-associated enhancement of the disease, which is an important issue for coronavirus vaccines.

Read the full article from KSU here