Hexbyte Glen Cove New research helps explain diversity of life and paradox of sex thumbnail

Hexbyte Glen Cove New research helps explain diversity of life and paradox of sex

Hexbyte Glen Cove

Credit: Pixabay/CC0 Public Domain

There are huge differences in species numbers among the major branches of the tree of life. Some groups of organisms have many species, while others have few. For example, animals, plants and fungi each have over 100,000 known species, but most others—such as many algal and bacterial groups—have 10,000 or less.

A new study, published in the Proceedings of the Royal Society B, tested whether and might help explain this mysterious pattern.

“We wanted to understand the diversity of life,” said paper co-author John Wiens, a professor in the University of Arizona Department of Ecology and Evolutionary Biology. “Why are most living things , plants and fungi?”

Wiens worked with a visiting scientist in his lab, Lian Chen from Nanjing Forestry University in China. They estimated rates of proliferation in 17 major groups that spanned all , including bacteria, protists, fungi, plants and animals. The hard part was to estimate how many species in each group were multicellular versus unicellular and how many reproduced sexually versus asexually. For five years, Chen sifted through more than 1,100 scientific papers and characterized the reproductive modes and cellularity of more than 1.5 million species.

The researchers found that both multicellularity and sexual reproduction helped explain the rapid proliferation of animal, plant and fungal species. The rapid proliferation of these three groups explains why they now include more than 90% of Earth’s known species.

Wiens and Chen also found that the rapid proliferation of sexual species may help explain the “paradox of sex,” or why so many species reproduce sexually, despite the disadvantages of sexual reproduction.

“For sexual species, only half the individuals are directly producing offspring. In an asexual species, every individual is directly producing offspring,” Wiens said. “Sexual reproduction is not as efficient. Another disadvantage of sexual reproduction is that you do need two individuals to make something happen, and those two individuals have to be the right sexes. Asexual species, on the other hand, only need one individual to reproduce.”

Chen and Wiens found a straightforward answer to the paradox of sex. The reason there are so many sexual species is because sexual species actually proliferate more rapidly than asexual species. This had not been shown across all of life before.

They also found that another explanation for the large number of sexual species is that sexual reproduction and multicellularity are strongly associated across the tree of life, and that multicellularity helps drive the large number of sexual species.

“Multicellularity is actually more important than sexual production. We did a that showed it is probably at least twice as important for explaining these patterns of diversity as sexual reproduction,” Wiens said.

While this study alone can’t pinpoint exactly why multicellularity is so important, researchers have previously suggested that it has to do with the variety of cell types within a multicellular organism.

“If you’re a single cell, there’s not much variety there,” Wiens said. “But multicellularity allows for different tissues or cell types and allows for diversity. But how exactly it leads to more rapid proliferation will need more study.”

Chen and Wiens also tested how their conclusions might change if most living species on Earth were species of bacteria that are still unknown to science.

“Most bacteria are unicellular and asexual. But because bacteria are much older than plants, animals and fungi, they have not proliferated as rapidly, even if there are billions of bacterial species,” Wiens said. “Therefore, multicellularity and sexual reproduction still explain the rapid proliferation of animals, plants and fungi.”

Future work will be needed to understand how multicellularity and sexual drive biodiversity. Wiens is also interested in how some groups are both multicellular and reproduce sexually yet don’t proliferate rapidly.

“We have some ideas,” he said. “One example is rhodophytes, the red algae. These are mostly marine, and we know from animals that marine groups don’t seem to proliferate as rapidly.”

More information:
Lian Chen et al, Multicellularity and sex helped shape the Tree of Life, Proceedings of the Royal Society B: Biological Sciences (2021). DOI: 10.1098/rspb.2021.1265

New research helps explain diversity of life and paradox of sex (2021, July 29)

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Hexbyte Glen Cove Research team develops new tool to help farmers make crop input decisions thumbnail

Hexbyte Glen Cove Research team develops new tool to help farmers make crop input decisions

Hexbyte Glen Cove

Credit: CC0 Public Domain

Reducing greenhouse gas emissions (GHGs) and nitrogen water pollution from agriculture are top environmental priorities in the United States. Key to achieving climate goals is helping producers navigate carbon markets, while also helping the environment and improving farm income.

A new tool developed by a University of Minnesota research team allows farmers to create a budget balance sheet of any reduction plans and see the economic and environmental cost, return and margins, all customized to fields under their management.

“With these numbers in mind, farmers can make more informed decisions on nitrogen mitigation that not only saves them money, but also significantly reduces pollutants to the environment,” said Zhenong Jin, who led the research and is an assistant professor in the Department of Bioproducts and Biosystems Engineering (BBE) in the College of Food, Agricultural and Natural Resource Sciences (CFANS).

Previous tools did not allow for customized predictions for every field in the U.S. corn belt, as the computational and storage costs of running these crop models at large scale would be very expensive.

As outlined in an article published in IOPscience, the research team built a series of machine-learning-based metamodels that can almost perfectly mimic a well-tested crop model at much faster speeds. Using the metamodels, they generated millions of scenario simulations and investigated two fundamental sustainability questions—where are the mitigation hotspots, and how much mitigation can be expected under different management scenarios.

“We synthesized four simulated indicators of agroecosystem sustainability—yield, N2O emissions, nitrogen leaching, and changes in soil organic carbon—into economic net as the basis for identifying hotspots and infeasible land for mitigation,” said Taegon Kim, CFANS research associate in the BBE department. The societal benefits include from GHG mitigation, as well as improved water and air quality.

“By providing key sustainability indicators related to upstream crop production, our metamodels can be a useful tool for food companies to quantify the emissions in their supply chain and distinguish mitigation options for setting sustainability goals,” said Timothy Smith, professor of Sustainable Systems Management and International Business Management in CFANS’s BBE department.

The study, conducted in the U.S. Midwest corn belt, found that:

  • Reducing nitrogen fertilizer by 10% leads to 9.8% fewer N2O emissions and 9.6% less nitrogen leaching, at the cost of 4.9% more soil organic carbon depletion, but only a 0.6% yield reduction over the study region.
  • The estimated net total annual social benefits are worth $395 million (uncertainty ranges from $114 million to nearly $1.3 billion), including a savings of $334 million by avoiding GHG emissions and water pollution, $100 million using less fertilizer, and a negative $40 million due to yield losses.
  • More than 50% of the net social benefits come from 20% of the study areas, which thus can be viewed as hot spots where actions should be prioritized.

“Our analysis revealed hot spots where excessive can be cut without yield penalty,” said Jin. “We noticed in some places that reducing nitrogen-related pollution comes at a cost of depleting in soil, suggesting that other regenerative practices, such as cover cropping, need to be bundled with nitrogen management.”

In the future, the team will expand the framework presented in this study and develop more advanced and accurate carbon qualification models through a combination of process-based models, artificial intelligence and remote sensing.

More information:
Taegon Kim et al, Quantifying nitrogen loss hotspots and mitigation potential for individual fields in the US Corn Belt with a metamodeling approach, Environmental Research Letters (2021). DOI: 10.1088/1748-9326/ac0d21

Research team develops new tool to help farmers make crop input decisions (2021, July 15)

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Hexbyte Glen Cove New research examines why some firms prepare for natural disasters and others don't thumbnail

Hexbyte Glen Cove New research examines why some firms prepare for natural disasters and others don’t

Hexbyte Glen Cove

Credit: Unsplash/CC0 Public Domain

Despite the increasing frequency and severity of floods, storms, wildfires and other natural hazards, some firms in disaster-prone areas prepare while others do not.

That issue was examined in a new study by Jennifer Oetzel, professor, American University and Chang Hoon Oh, William & Judy Docking Professor of Strategy, University of Kansas published in the Strategic Management Journal (SMJ).

“Due to the increased frequency and severity of floods, storms, epidemics, wildfires and other anticipated over the coming decades (according to the National Oceanic and Atmospheric Administration), there is growing pressure on managers and their firms to develop strategies for managing natural disaster risk,” write the researchers.

“Preparing for future events that may never occur is challenging. Day-to-day events tend to crowd out long-term planning, but business continuity depends on managers anticipating and planning for large scale disasters. For these reasons, our goal in this study was to understand the antecedents associated with disaster preparation so that managers can better prepare for .”

They defined disaster preparedness as the acquisition of the skills and capabilities needed to reduce damage to a firm, to minimize disruption to the supply chain, and more generally, and to save lives and protect employees.

Disaster preparedness can entail a wide variety of initiatives including conducting an assessment of firm vulnerability to natural disasters, establishing a natural disaster response plan, training employees about natural , purchasing insurance, developing a business continuity plan, and arranging to move business operations temporarily to another location, among others.

Emergency preparedness pays off. A review conducted by the Wharton Risk Center that focused on floods suggested that for every dollar spent on flood risk reduction, on average, five dollars is saved through avoided and reduced losses. But despite the documented value of preparing, most firms fail to do so.

“Since not all firms located in disaster prone areas prepare for disasters, what are the antecedents to disaster preparation? To answer this question,” write the authors, “we looked at several factors that are likely to affect whether or not businesses will prepare. The first factor is organizational experience with disaster, which can be a transformational and powerful motivator for change when managers see the value of disaster preparation and planning.”

The mechanisms driving the relationship between experience and preparedness are multifaceted. Managers may fail to learn from past experiences if they do not consider a recently experienced disaster as representative of future events. Even when managers learn from experience and see preparation as valuable, they may lack the organizational influence and find that they are unable to leverage learning to inform decision-making.

Aside from experience, strategic decisions around disaster preparation are likely to be affected by managers’ subjective judgments and/or knowledge about disaster risks. Depending upon the nature of their experience, managers may either over- or under-estimate disaster risk and thus over or under prepare.

Research has also shown that willingness to learn from other organizations about how to manage natural disaster risk is also important. External sources of information provide different perspectives and may help organizations to avoid internal biases in decision making.

“Another set of factors that are presumed to affect preparation are the characteristics of disasters, including their type, frequency, and impact,” write the researchers. “Historical records and scientific data indicate whether or not a given location is subject to natural disasters and, if so, of what type.

“Natural scientists examining climate change trends are raising concerns, however, that past experiences may not be predictive of the future. In certain geographic areas (e.g., Houston, Texas), the frequency of major disasters may be increasing substantially, deviating significantly from the past.”

In conducting two studies—an international survey in 18 disaster-prone countries and a U.S. survey in New York City and Miami—Oetzel and Oh found that managers are more likely to prepare when their companies experienced prior disasters. The likelihood of preparedness is even higher when companies work with and learn from other organizations and stakeholders.

“Managers operating in locations characterized by high impact, low frequency disasters are more willing to learn from others,” they wrote. “In contrast, managers in areas characterized by low impact, high frequency , are more likely to prepare alone. Since effective disaster preparation typically entails working with, and learning from others, those companies that choose a go-it-alone strategy may misjudge disaster risk.”

The SMJ is published by the Strategic Management Society (SMS), comprised of 3,000 academics, business practitioners, and consultants from 80 countries, focuses on the development and dissemination of insights on the strategic management process, as well as on fostering contacts and interchanges around the world.

More information:
Jennifer Oetzel et al, A storm is brewing: Antecedents of disaster preparation in risk prone locations, Strategic Management Journal (2021). DOI: 10.1002/smj.3272

Provided by
Strategic Management Society

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Hexbyte Glen Cove Research suggests fly brains make predictions, possibly using universal design principles thumbnail

Hexbyte Glen Cove Research suggests fly brains make predictions, possibly using universal design principles

Hexbyte Glen Cove

Flies make exceptionally fast escape maneuvers in response to visual threats (pink star). The behavior unfolds so rapidly that there is not time for vestibular (haltere) or visual feedback to control flight. Visual prediction that flows through the vertical sensing system’s “information bottleneck” may help control flight in this open-loop interval. This information could flow directly to the wing steering muscles, as an instantiation of the so-called “control-loop” hypothesis. Credit: This image was created by authors S.E. Palmer and S. Wang, with 3D fly illustrations from D.A. Drummond.

Flies predict changes in their visual environment in order to execute evasive maneuvers, according to new research from the University of Chicago. This reliance on predictive information to guide behavior suggests that prediction may be a general feature of animal nervous systems in supporting quick behavioral changes. The study was published on May 20 in PLOS Computational Biology.

Animals use their sensory nervous systems to take in about their environments and then carry out certain behaviors in response to what they detect. However, the takes time to process this , meaning that the environment can change by the time the previous information has been fully processed.

“This is really important in predator/prey interactions,” said senior author Stephanie Palmer, Ph.D., Associate Professor of Organismal Biology and Anatomy at UChicago. “For a fly, everything is trying to eat you, and you want to avoid being eaten. However, the fly’s environment is rapidly changing, and the neurons they have are laggy. We wanted to study how were able to execute quick evasive behaviors to avoid being eaten by predators when ongoing feedback from their sensory systems hasn’t been processed.”

To answer this question, the investigators took a highly interdisciplinary approach. “This is a project born out of this new era of open science sharing,” Palmer said. “We were able to take the precise behavioral recordings made by another group and use them for a theoretical, computational neuroscience question: Does the fly’s visual system make predictions using the initial detection of a threat that can span the lag time in processing of additional feedback as the fly starts its evasive behavior?”

Previous work from first author Siwei Wang, Ph.D., a postdoctoral researcher in Palmer’s group, looked at a theoretical model of how encoding motion in the fly visual system might work. “I had an idea of how to extend these ideas to prediction, and this study allowed me to compare my model to real life behavioral data to test my theory,” Wang said.

Using detailed diagrams of the connectivity between neurons in the fly visual system, the researchers made a simulation of the visual response as they fed in the previously recorded behavioral data set. “We compared what an optimal prediction would look like and what the fly’s prediction looks like, and then we broke open the simulation to try to identify which parts were the most important for making these predictions,” Palmer said.

The authors first identified that sensory data about the fly’s visual world passes though an information bottleneck, where some of the sensory data is thrown out by the fly’s brain because it simply does not have enough computing power to handle the amount of information it is taking in. However, the fly cannot indiscriminately discard visual information, because some of it might be useful for making predictions.

The authors identified structures called axonal gap junctions, which are physical channels connecting the neurons, that mediate an optimal form of this information bottleneck and are critical for both filtering out the unnecessary information and preserving the necessary information to make predictions.

The investigators further found that a subpopulation of these vertical motion sensory neurons that are involved in making predictions is unique in that it is also directly connected to the fly’s flight steering neurons. This suggests that there is direct input from the neurons responsible for making predictions about the fly’s environment to neurons that control the fly’s behavior. This might explain how predictions that the fly is making are able to quickly influence its behavior.

Identification of these structures and the ability of the fly visual system to make predictions is likely to drive insight into how other animals’ nervous systems make similar predictions.

“Cracking open the black box of how the fly does this has revealed what we think are universal design principles that the nervous systems of other animals probably also use,” Palmer said. “We’re interested in searching for another example of -guiding behavior in another animal and asking if what we found in the fly really does apply broadly across species.”

Ultimately, this kind of theoretical neuroscience may shed light on how our human brains function. “One of our greatest challenges as humans is understanding how everything inside our head works. Insights from work on flies can be generalizable and actually give us clues to how our brains operate,” Palmer said.

Wang said the results could even have implications for understanding neurodegenerative diseases like Alzheimer’s disease, where the brain loses the ability to make predictions. If the insights gained from these fly studies hold true in humans, it could help uncover new specific targets for therapeutic intervention. “We’re still a long way from that, but this research in flies is setting the ground work to allow others to do that down the line,” Wang said.

More information:
Siwei Wang et al, Maximally efficient prediction in the early fly visual system may support evasive flight maneuvers, PLOS Computational Biology (2021). DOI: 10.1371/journal.pcbi.1008965

Research suggests fly brains make predictions, possibly using universal design principles (2021, May 20)
retrieved 21 May 2021
from https://phys.org/news/2021-05-brains-possibly-universal-principles.html

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Hexbyte Glen Cove New research may explain shortages within STEM careers thumbnail

Hexbyte Glen Cove New research may explain shortages within STEM careers

Hexbyte Glen Cove

Credit: Unsplash/CC0 Public Domain

A new study by the University of Georgia revealed that more college students change majors within the STEM pipeline than leave the career path of science, technology, engineering and mathematics altogether.

Funded by a National Institutes of Health grant and a National Science Foundation Postdoctoral Fellowship and done in collaboration with the University of Wisconsin, the study examined interviews, surveys and institutional data from 1,193 students at a U.S. midwestern university for more than six years to observe a single area of the STEM : biomedical fields of study.

Out of 921 students who stayed in the biomedical pipeline through graduation, almost half changed their plans within the biomedical fields.

“This was almost double the number of students who left biomedical fields altogether,” said Emily Rosenzweig, co-author of the study and assistant professor in the Mary Frances Early College of Education’s department of educational psychology. “This suggests that if we want to fully understand why there are shortages in certain STEM careers, we need to look at those who change plans within the pipeline, not just those who leave it.”

Rosenzweig examined students’ motivations for changing career plans and found that students were more often inspired to make a change because a new field seemed more attractive.

This finding pointed to an underexplored research area that educators, policymakers and administrators should devote more attention to in the future. Rather than focusing only on what makes students disenchanted with a particular career, factors that make alternative career paths seem valuable to students need to be considered.

“The sheer number of changes made by students who remained in the biomedical pipeline highlights the divergence of paths students take in their career decision-making,” Rosenzweig said. “We should not simply assume that students are staying on course and progressing smoothly toward intended careers just because they have not left the [STEM] pipeline.”

Ultimately, the research provides new insights about students’ motivations for choosing various careers inside the STEM pipeline and demonstrates the importance of understanding this group if schools are to promote retention in particular STEM careers.

More information:
Emily Q. Rosenzweig et al, Inside the STEM pipeline: Changes in students’ biomedical career plans across the college years, Science Advances (2021). DOI: 10.1126/sciadv.abe0985

New research may explain shortages within STEM careers (2021, May 12)
retrieved 13 May 2021
from https://phys.org/news/2021-05-shortages-stem-careers.html

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Hexbyte Glen Cove New research sets stage for development of salmonella vaccine thumbnail

Hexbyte Glen Cove New research sets stage for development of salmonella vaccine

Hexbyte Glen Cove

Salmonella forms a biofilm. Credit: CDC

With the COVID-19 vaccines on many people’s minds, some may be surprised to learn that we do not yet have vaccines for many common infectious diseases.

Take , for example, which can infect people through contaminated food, water and animals. According to the World Health Organization, non-typhoidal salmonella infection affects more than 95 million people globally each year, leading to an estimated 2 million deaths annually. There is no approved vaccine for salmonella in humans, and some strains are antibiotic-resistant.

But just as scientists spent decades doing the basic research that made the eventual development of the COVID-19 vaccines possible, University of Florida researchers led by Mariola Edelmann in the department of microbiology and cell science, UF/IFAS College of Agricultural and Life Sciences, are laying the groundwork for an effective vaccine for salmonella and other hard-to-treat bacterial infections. In their study supported by the National Institutes of Health and published in PLOS Pathogens, the UF/IFAS scientists demonstrate a novel approach to triggering immunity against salmonella.

This approach takes advantage of how cells communicate with each other, said Winnie Hui, first author of the study, which was conducted while she was a doctoral candidate in microbiology and cell science.

“Cells communicate with each other through particles called extracellular vesicles or EVs. Think of these like molecular telephones that let cells talk to each other. We wanted to know if some of those messages included information related to immune response,” said Hui, who graduated from the UF/IFAS College of Agricultural and Life Sciences in 2019 and is now a postdoctoral researcher in the UF College of Medicine, division of rheumatology and clinical immunology.

“Host EVs have not been previously studied in the context of fighting enteric bacterial infections, so that is part of what makes our approach new and adds to the field,” said Edelmann, senior author on the study, Hui’s dissertation director and an assistant professor of microbiology and .

Edelmann hypothesized that a specific type of EVs called exosomes were part of the immune response against salmonella and may one day hold the key to developing a vaccine.

To test their idea, the research team took exosomes from white blood cells infected with salmonella. Inside those exosomes, which measure just a few dozen nanometers across, they found salmonella antigens, which are bits of salmonella protein known to trigger an .

Next, the researchers wanted to know if these exosomes might function as a vaccine, helping the body build up its defenses against salmonella, said Lisa Emerson, one of the study’s co-authors and a doctoral student in Edelmann’s laboratory.

“We put the exosomes in ‘nanobubbles’ that the mice inhaled. Later, we ran tests to see how their immune systems responded,” said Emerson, who is in the UF/IFAS College of Agricultural and Life Sciences.

The researchers found that after they introduced the exosomes containing salmonella antigens, the exosomes localized to tissues that produce mucous, activating specific cells at these sites. Weeks later, mice developed antibodies against salmonella and specific cellular immune responses, which typically target this bacterium for elimination. For the researchers, this is a promising result.

“There are two types of immune responses generated when our bodies encounter a pathogen. The first one is called innate immunity, which is an immediate response to an , but it is also less specific. The other response is called adaptive immunity, and this protective response is specifically tailored to a given pathogen, but it also takes longer to develop. Exosomes generated by infected white blood stimulated both of these responses in animals,” said Hui.

While these results show promise, more research will be needed before we have a salmonella that works in humans, Hui said.

“Our study has identified a novel role of exosomes in the protective responses against salmonella, but we also think that exosomes can find broader applications for other intestinal infections and beyond,” Edelmann said.

“Exosomes have this unique capability to encapsulate precious cargo while enabling its targeted delivery to tissue of interest. For many conditions and infections, this precise delivery of therapeutic payload is what makes a difference, and we are currently also evaluating exosomes in delivering cargo to other tissues of choice,” said Edelmannn whose work is supported by several federal funds focused on the roles of extracellular vesicles in bacterial infections and disease and host-directed therapies against intestinal infections.

More information:
Winnie W. Hui et al, Antigen-encapsulating host extracellular vesicles derived from Salmonella-infected cells stimulate pathogen-specific Th1-type responses in vivo, PLOS Pathogens (2021). DOI: 10.1371/journal.ppat.1009465

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Hexbyte Glen Cove Research inside hill slopes could help wildfire and drought prediction thumbnail

Hexbyte Glen Cove Research inside hill slopes could help wildfire and drought prediction

Hexbyte Glen Cove

Jackson School Assistant Professor Daniella Rempe directing the drillers on a ridgetop borehole. Credit: Michelle Pedrazas/ UT Jackson School of Geosciences

A first-of-its-kind study led by The University of Texas at Austin has found that rock weathering and water storage appear to follow a similar pattern across undulating landscapes where hills rise and fall for miles.

The findings are important because they suggest that these patterns could improve predictions of wildfire and landslide risk and how droughts will affect the landscape, since and influence how and nutrients flow throughout landscapes.

“There’s a lot of momentum to do this work right now,” said study co-author Daniella Rempe, an assistant professor at the UT Jackson School of Geosciences Department of Geological Sciences. “This kind of data, across large scales, is what is needed to inform next-generation models of land-surface processes.”

The research was led by Michelle Pedrazas, who conducted the work while earning a master’s degree at the Jackson School. It was published in the Journal of Geophysical Research: Earth Surface.

Despite the importance of what’s happening inside hills, most computer models for simulating landscape behavior don’t go deeper than the soil due to a lack of data that can scale to large areas, Rempe said.

This study helps fill that knowledge gap, being the first to methodically sample the interiors of a sequence of slopes. The research focused on investigating the “critical zone,” the near surface layer that includes trees, soils, weathered and fractures.

“This study helps to unravel a mystery in the critical zone research community, the linkage between bedrock weathering, topography and storage of water in mountainous watersheds,” said Eric Pierce, the director of the Environmental Sciences Division at Oak Ridge National Laboratory who was not involved with the study.

In 2018, researchers from the Jackson School of Geosciences and other institutions travelled to Northern California to conduct a first-of-its-kind field study to sample the interiors of a sequence of hillslopes. The research revealed that rock weathering and water storage appear to follow a similar pattern across undulating landscapes where hills rise and fall for miles. Since weathering and water storage influence how water and nutrients flow throughout landscapes, the research could help improve predictions of wildfire and landslide risk and how droughts will affect the landscape. Credit: Michelle Pedrazas/UT Jackson School of Geosciences

The research site is in Northern California and is part of a national network of Critical Zone Observatories. The scientists drilled 35 boreholes across a series of hill slopes and their valleys to collect subsurface samples and other data. They also collected a core sample at the peak of each hill slope that captured the entire height of the hill—a distance that varied from 34 to 57 feet (10.5 to 17.5 meters).

The samples revealed deeper weathering and fracturing in hilltops and thinner weathering in valleys, in addition to weathering that penetrates deeper into shorter hill slopes than taller ones.

This finding is important because it suggests that computer models could use this scaling trend to model the extent of weathering in similar undulating terrain.

Where water is stored in the weathered rocks of hill slopes is an important question, especially during the arid summers experienced in the field area. Research led by Rempe in 2018 revealed that trees tap into water stored as “rock moisture” in the fractures and pores of critical zone rocks during droughts.

This study also revealed rock moisture in the critical zone—but only within the first 20 feet of weathered rock.

Learning more about how hill slopes store their water can help researchers determine what areas are most at risk of becoming wildfire hazards. Pedrazas said that the wildfire connection was clear when they collected the field data in 2018. Wildfires blazing in other parts of California turned the sun red and filled the sky with smoke. The setting underscored the fact that knowing what’s happening at the surface is closely connected to what’s happening within the hills.

“We were really seeing the potential impact of our research, [the importance of] where is the water, and when are trees really going to dry up, and what risk that is for society,” Pedrazas said.

More information:
Michelle A. Pedrazas et al, The relationship between topography, bedrock weathering, and water storage across a sequence of ridges and valleys, Journal of Geophysical Research: Earth Surface (2021). DOI: 10.1029/2020JF005848

Research inside hill slopes could help wildfire and drought prediction (2021, April 19)
retrieved 20 April 2021
from https://phys.org/news/2021-04-hill-slopes-wildfire-drought.html

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Hexbyte Glen Cove Lipid research may help solve COVID-19 vaccine challenges thumbnail

Hexbyte Glen Cove Lipid research may help solve COVID-19 vaccine challenges

Hexbyte Glen Cove

University of Texas at Dallas scientists developed a method to stabilize liposomes in a crystalline exoskeleton, which allows the biomolecules to remain stable at room temperature. This illustration depicts a proteoliposome — a spherical bilayer of fat molecules (white and blue) — stabilized in a structure called a zeolitic-imidazole framework composed of zinc acetate and methylimidazole. Inserted into the lipid bilayer — which mimics a cell membrane — are modeled structures of CopA proteins, with a section (in pink) that resides inside the lipid and sections above the lipid surface (brown) and slightly inside the liposome (also brown, but inside). Credit: University of Texas at Dallas

New research by University of Texas at Dallas scientists could help solve a major challenge in the deployment of certain COVID-19 vaccines worldwide—the need for the vaccines to be kept at below-freezing temperatures during transport and storage.

In a study published online April 13 in Nature Communications, the researchers demonstrate a new, inexpensive technique that generates crystalline exoskeletons around delicate liposomes and other nanoparticles and stabilizes them at room temperature for an extended period—up to two months—in their proof-of-concept experiments.

The Moderna and Pfizer/BioNTech COVID-19 vaccines use lipid nanoparticles—basically spheres of fat molecules—to protect and deliver the messenger RNA that generates a vaccine recipient’s immune response to the SARS-CoV-2 virus.

“The expense of keeping these vaccines very cold from the time they’re made to the time they’re delivered is a challenge that needs to be addressed, especially because many countries don’t have sufficient infrastructure to maintain this kind of cold chain,” said Dr. Jeremiah Gassensmith, associate professor of chemistry and biochemistry and of bioengineering at UT Dallas and a corresponding author of the study. “Although we did not include in this work the specific used in current COVID-19 vaccines, our findings are a step toward stabilizing a lipid nanoparticle in a way that’s never been done before, so far as we know.”

The idea for the research project began during a coffee-break discussion between Gassensmith and Dr. Gabriele Meloni, a corresponding co-author of the study and assistant professor of chemistry and biochemistry in the School of Natural Sciences and Mathematics at UT Dallas.

Gassensmith’s area of expertise is biomaterials and , while Meloni’s research focus is transmembrane transporter proteins. These proteins reside within cell membranes and are crucial for moving a variety of small molecules, including ions and trace metals, in and out of cells for several purposes.

“Membrane proteins sit in a , which is a lipid bilayer,” Meloni said. “To study their structure and biophysical and biochemical properties, we must extract these proteins from the membrane using detergents and then reconstitute them back into an artificial membrane—a proteoliposome—that mimics the proteins’ natural environment.”

Shell Creation

Lipid nanoparticles and liposomes are similar in structure, and neither are thermodynamically stable at room temperature, Gassensmith said. The lipid structures can fuse or aggregate, exposing any embedded or cargo to degradation.

“One of the challenges in my field of research is that both membrane proteins and lipid bilayers are very delicate and intrinsically metastable, and we’re trying to combine them in order to understand how these proteins function,” Meloni said. “We have to handle them carefully and prepare them fresh each time. They cannot be stored for long periods and are not easily shipped to colleagues in other labs.”

The researchers joined forces to develop a methodology to stabilize this kind of lipid system and demonstrated their results using transmembrane proteins from Meloni’s lab as a case study.

They mixed liposomes—some with embedded proteins, some without—with a combination of two inexpensive chemicals, zinc acetate and methylimidazole, in a buffer solution. In about a minute, a crystal matrix began to form around individual liposomes.

“We think that the lipids interact with the zinc just strongly enough to form an initial zinc-methylimidazole structure that then grows around the lipid sphere and completely envelops it, like an exoskeleton,” Gassensmith said. “It’s analogous to biomineralization, which is how certain animals form shells. We sort of co-opted nature in creating this totally fake shell, where the biomacromolecules—the lipids and proteins—catalyze the growth of this exoskeleton.”

The ability of biomimetic shells to form around biological molecules is not new, Gassensmith said, but the process hasn’t worked well with lipids or liposomes because the metal salts that comprise the shell material suck water out of the liposomes by osmosis and cause them to explode.

“One of the keys to this research was identifying the buffer solution in which everything resides,” Gassensmith said.

Building a Buffer

Three graduate students collaborated on the project to develop the unique buffer medium that allows the reaction to occur.

“The buffer medium maintains the ionic strength of the solution and keeps the pH stable so that when you add a huge amount of metal salts, it doesn’t osmotically shock the system,” said Fabián Castro BS’18, a chemistry doctoral student in Gassensmith’s lab and a lead author of the study.

Castro and co-lead authors Sameera Abeyrathna and Nisansala Abeyrathna, chemistry doctoral students (and siblings) in Meloni’s lab, worked together to develop the buffer formulation.

Once the biomolecules have grown a shell, they are locked in, and the lipids remain stable. While the exoskeleton is very stable, it has a fortuitous Achilles’ heel.

“The shell will dissolve if it encounters something that is attracted to zinc,” Gassensmith said. “So, to release and reconstitute the liposomes, we used a zinc chelating factor called EDTA (ethylenediaminetetraacetic acid), which is a common, inexpensive food additive and medicine used to treat lead poisoning.”

In addition to the laboratory experiments, in another proof-of concept exercise, Gassensmith mailed through the U.S. Postal Service a sample of the stabilized lipid particles to his mother in Rhode Island. She shipped them back to Texas, but because the COVID-19 pandemic forced the shutdown of most UT Dallas research labs in 2020, the samples sat untouched for about two months until the graduate students returned to campus to examine them. Although the informal experiment lasted much longer than the researchers had expected, the samples survived and functioned “just fine,” Gassensmith said.

“This project required two different types of expertise—my group’s expertise in membrane transport proteins and Dr. Gassensmith’s long track record working with metal-organic frameworks,” Meloni said. “Our success clearly demonstrates how such collaborative research can bring about novel and useful results.”

More information:
Fabian C. Herbert et al, Stabilization of supramolecular membrane protein–lipid bilayer assemblies through immobilization in a crystalline exoskeleton, Nature Communications (2021). DOI: 10.1038/s41467-021-22285-y

Lipid research may help solve COVID-19 vaccine challenges (2021, April 15)
retrieved 15 April 2021
from https://phys.org/news/2021-04-lipid-covid-vaccine.html

This d

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Hexbyte Glen Cove Research uncovers a critical factor in the assembly of cell division machinery in bacteria thumbnail

Hexbyte Glen Cove Research uncovers a critical factor in the assembly of cell division machinery in bacteria

Hexbyte Glen Cove

sepH is required for sporulation septation in Streptomyces venezuelae. (A) Schematic illustrating the multicellular life style of Streptomyces including the two FtsZ-dependent modes of cell division that occur in vegetative and sporogenic hyphae: cross-wall formation and sporulation septation. (B) Schematic of the predicted SepH domain organization including the N-terminal DUF3071 domain containing a helix-turn-helix (HTH) motif and the unstructured C-terminal domain. Numbers indicate corresponding amino acid positions. (C) Cryo-scanning electron micrographs of sporogenic hyphae from wild-type (WT) S. venezuelae, the ΔsepH mutant (SV56), and the complemented mutant strain ΔsepH/sepH+ (MB747). Scale bars: 2 μm. (D) Subcellular co-localization of fluorescently labeled FtsZ (FtsZ-mCherry) and SepH (SepH-YPet) in vegetative and sporulating hyphae. Fluorescent gene fusions were expressed in the WT background (MB751). White arrow heads point at co-localization at cross-walls in vegetative hyphae and the asterisk denotes a sporogenic hypha undergoing sporulation septation. Scale bar: 5 µm.

Researchers have identified a previously undescribed component that is important for the ability of bacteria to divide.

The findings by John Innes Centre researchers address the fundamental question as to how proliferate.

This work creates opportunities for further research into the cell biology of these organisms including studies aimed at better understanding the life cycle of harmful bacteria.

To grow and proliferate, bacteria (including the good and the bad) need to divide. Central to this process is a called FtsZ which assembles into a ring-like structure, called the Z-ring. For most bacteria, the Z-ring is essential to build the cell division machinery and for the synthesis of a dividing wall that allows the bacteria to physically separate.

Previously, there was little understanding of the mechanisms important for Z-ring assembly in a group of bacteria that include several medically and industrially relevant bacteria, such as the causative agent for Tuberculosis (TB), Mycobacterium tuberculosis, or the prolific antibiotic producers Streptomyces.

In a new study, researchers in the group of Dr. Susan Schlimpert identified a novel cell division protein, called SepH, in Streptomyces that directly regulates the assembly of Z-ring.

SepH is a highly conserved protein found not only in Streptomyces bacteria but also more distantly related bacteria, including several human pathogens such as M. tuberculosis and Corynebacterium diphtheriae.

Using a combination of in vivo studies, biochemical analyses and live-cell imaging, the team demonstrated that SepH has a similar function in cell division in two different model species: the filamentous-growing, antibiotic producer Streptomyces venezuelae and the single-cell, non-pathogenic cousin of M. tuberculosis, M. smegmatis.

“Having discovered a novel regulator that directly interacts with the cell division machinery, we now have the opportunity to further dissect this interaction with the aim of identifying strategies for inhibiting this interaction and thereby preventing cell division. This would be of particular interest with respect to the treatment of TB, an infection that still leads to the death of over one million people per year,” said Dr. Schlimpert.

Dr. Matt Bush, co-first author of the study said: “SepH was predicted to be a DNA-binding protein which implied that it regulates the production of other proteins. However, the protein domain that was predicted to mediate DNA-binding was in fact crucial for the interaction with the protein, FtsZ. That was unexpected and exciting, as there are not many other examples known in which the DNA-binding protein is actually mediating a protein-protein interaction.”

The next focus of research will be to gain a better mechanistic understanding of how SepH binds FtsZ and modulates FtsZ activity.

“A conserved protein directly regulates FtsZ dynamics in filamentous and unicellular actinobacteria” appeared in eLife.

More information:
Félix Ramos-León et al. A conserved cell division protein directly regulates FtsZ dynamics in filamentous and unicellular actinobacteria, eLife (2021). DOI: 10.7554/eLife.63387

Journal information:

Research uncovers a critical factor in the assembly of cell division machinery in bacteria (2021, March 22)
retrieved 22 March 2021
from https://phys.org/news/2021-03-uncovers-critical-factor-cell-division.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

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Hexbyte Glen Cove Compilation of research on PFAS in the environment thumbnail

Hexbyte Glen Cove Compilation of research on PFAS in the environment

Hexbyte Glen Cove

Per- and polyfluoroalkyl substances (PFAS) are a class of man-made chemical compounds and a current, emerging concern to environmental health. PFAS substances have unique characteristics-resistance to heat, water, oil and stains-that make them useful in a variety of industrial applications and popular in consumer goods. Many PFAS are stable and long-lasting in the environment, acquiring the name “forever chemicals.” Industrial use of some of these compounds has been halted; however, many derivatives are still in commerce and more are under development. PFAS are now found in many compartments of the environment.

In order to manage PFAs in the environment, a lot of research has been directed at understanding their sources, fate and transport in the environment, and their potential effects on humans and wildlife. Recently, Environmental Toxicology and Chemistry (ET&C) published a special issue dedicated to PFAS with 32 articles, providing a valuable summarization of risk assessment approaches for PFAS, which are needed for environmental managers and to set appropriate drinking water standards and health advisory guidelines.

The published research illustrates that PFAS are ubiquitous and raise more questions than answers about their potential toxicity to humans and wildlife. The articles in the issue report that PFAS were found near defense bases, , treatment plants and waste disposal sites but also in remote, less inhabited areas. PFAS were detected in breeding kittiwakes in Svalbard, Norway, and ducks in Australian estuaries. They were found in hens’ eggs, soil, tadpoles, zebrafish, house crickets; the list goes on. The breadth of the published research illustrates that PFAS have dispersed in every medium in the environment (soil, water and wildlife).

In some of the studies, the presence of PFAS was related to a nearby source while in others it was not determined. For example, the authors of the article that investigated PFAS in Australian ducks did find a correlation between local sources of PFAS and bioaccumulation in ducks and noted that “Human health risk assessment showed that only ducks inhabiting wetlands near local sources of PFAS were likely to pose a risk to consumers,” and continued, “Management of food consumption from these locations is an effective measure to limit exposure.” In another study published in this same issue, long-chain PFAS were found in eight across ten European glacial lakes in the Alps region, and while correlated to urban areas, could not be attributed to a specific, nearby industry source.

The issue illustrates that there are a tremendous number of PFAS substances, and it is a challenge for environmental managers and regulatory bodies to devise an approach to identify, understand and manage them all. The series provided a great review of the state of the science of PFAs risk assessment and also identified data gaps and the work needed to fill them in order to devise an effective approach to manage PFAS.

Provided by
Society of Environmental Toxicology and Chemistry

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