ReportWire

Tag: PNAS

  • Making sense of life’s random rhythms

    Making sense of life’s random rhythms

    [ad_1]

    Newswise — CLEVELAND–Life’s random rhythms surround us–from the hypnotic, synchronized blinking of fireflies…to the back-and-forth motion of a child’s swing… to slight variations in the otherwise steady lub-dub of the human heart.

    But truly understanding those rhythms—called stochastic, or random, oscillations—has eluded scientists. While researchers and clinicians have some success in parsing brain waves and heartbeats, they’ve been unable to compare or catalogue an untold number of variations and sources.

    Gaining such insight into the underlying source of oscillations “could lead to advances in neural science, cardiac science and any number of different fields,” said Peter Thomas, a professor of applied mathematics at Case Western Reserve University.

    Thomas is part of an international team that says it has developed a novel, universal framework for comparing and contrasting oscillations–regardless of their different underlying mechanisms—which could become a critical step toward someday fully understanding them.

    Their findings were recently published in Proceedings of the National Academy of Sciences.

    “We turned the problem of comparing oscillators into a linear algebra problem,” Thomas said. “What we have done is vastly more precise than what was available before. It’s a major conceptual advance.”

    The researchers say others can now compare, better understand—and even manipulate—oscillators previously considered to have completely different properties.

    “If your heart cells aren’t synchronized, you die of atrial fibrillation,” Thomas said. “But if your brain cells synchronize too much, you have Parkinson’s disease, or epilepsy, depending on which part of the brain the synchronization occurs in. By using our new framework, that heart or brain scientist may be able to better understand what the oscillations could mean and how the heart or brain is working or changing over time.”

    Swaying skyscrapers and brain waves

    Thomas said the researchers—who included collaborators from universities in France, Germany and Spain—found a new way to use complex numbers to describe the timing of oscillators and how “noisy,” or imprecisely timed, they are.

    Most oscillations are irregular to some extent, Thomas said. For example, a heart rhythm is not 100% regular. A natural variation of 5-10% in the heartbeat is considered healthy. 

    Thomas said the problem with comparing oscillators can be illustrated by considering two markedly different examples: brain rhythms and swaying skyscrapers.

    “In San Francisco, modern skyscrapers sway in the wind, buffeted by randomly shifting air currents—they’re pushed slightly out of their vertical posture, but the mechanical properties of the structure pull them back,” he said. “This combination of flexibility and resilience helps high-rise buildings survive shaking during earthquakes. You wouldn’t think this process could be compared with brain waves, but our new formalism lets you compare them.”

    How their findings might help either discipline—mechanical engineering and neuroscience—may be unknown right now, Thomas said, comparing the conceptual advance to when Galileo discovered Jupiter’s orbiting moons.

    “What Galileo realized was a new point of view, and while our discovery is not as far-reaching as Galileo’s, it is similarly a change in perspective,” he said. “What we report in our paper is an entirely new point of view on stochastic oscillators.”

     

                ###

    Case Western Reserve University is one of the country’s leading private research institutions. Located in Cleveland, we offer a unique combination of forward-thinking educational opportunities in an inspiring cultural setting. Our leading-edge faculty engage in teaching and research in a collaborative, hands-on environment. Our nationally recognized programs include arts and sciences, dental medicine, engineering, law, management, medicine, nursing and social work. About 6,000 undergraduate and 6,300 graduate students comprise our student body. Visit case.edu to see how Case Western Reserve thinks beyond the possible.

     

     

     

    [ad_2]

    Case Western Reserve University

    Source link

  • Rutgers Researchers Identify Lipid Vascular ‘ZIP code’

    Rutgers Researchers Identify Lipid Vascular ‘ZIP code’

    [ad_1]

    Newswise — New Brunswick, N.J., August 14, 2023 – Researchers at Rutgers Cancer Institute of New Jersey and Rutgers New Jersey Medical School (NJMS), together with other collaborating groups, have discovered the first lipid vascular ‘ZIP code’ in the lungs. Getting a drug to where it is needed in the human body is critical for successfully treating diseases including cancer and avoiding toxic side-effects, but it remains a major challenge. One creative option has been to identify the unique protein receptors that are present on the surface of blood vessels at specific sites in the body that act like vascular ZIP codes. These ZIP codes can be physically paired with a ligand such as a small protein or antibody that can be harnessed to guide and deliver a package such as a drug or a diagnostic imaging agent to their specific molecular addresses. Some of these ligand-receptor pairs are already undergoing testing in clinical trials with anti-cancer and anti-obesity drugs. 

    Prior to the researcher’s findings, all vascular ZIP codes have been proteins. Their discovery uncovers a previously unrecognized lipid network of ZIP codes in blood vessels and opens up a new world of possibilities for improved diagnostics and treatments, including patients with severe human respiratory diseases such as emphysema, COVID-19, COPD and lung cancer. 

    In 2008, the researchers discovered a ligand peptide that bound to the surface of lung vascular endothelial cells and could deliver a cell death notice directly to the lungs in mice. However, their usual biochemical and genetic methods failed to identify the corresponding lung vascular ZIP code that the ligand was binding to. “The problem was that we had been looking for a protein,” said Wadih Arap, MD, PhD, director of Rutgers Cancer Institute at University Hospital Newark, professor and chief of the Division of Hematology/Oncology, Department of Medicine, Rutgers NJMS and a co-lead author. “Our long series of frustrating failures led us to consider that the elusive target might be another type of molecule, perhaps a lipid; that was a eureka moment.”

    The lipid ZIP code that they discovered on lung blood vessels is called C16-ceramide (also known as palmitoyl ceramide). It belongs to a family of closely related lipid molecules that perform many important cellular functions. These include helping viruses like Ebola and SARS-CoV-2 get into cells, and also triggering cell death. Increased levels of ceramides have long been known to be associated with many lung diseases. Thus, C16-ceramide represents an unexplored avenue for many different diagnostic or therapeutic applications. As Renata Pasqualini, PhD, a resident member of Rutgers Cancer Institute and chief of the Division of Cancer Biology, Department of Radiation Oncology at NJMS another co-lead author remarked, “imaging plays such an essential role in evaluating the lungs—both, anatomically and functionally—that we felt it was an opportunity to make a clinical difference. Whether it is for pulmonary screening, establishing a diagnosis, or monitoring disease severity, our approach and findings will hopefully represent an advance in this area.” 

    To solidify their discovery of a new lipid vascular ZIP code and ligand pair, they tested their hypothesis in genetically engineered ceramide-deficient mice and showed that the ligand was no longer able to target the lungs. To begin to demonstrate what this might mean for patients, they tested two candidate medical applications. First, they showed that it could potentially be used for early diagnosis and monitoring of certain lung diseases by attaching the ligand to gold nanoparticles, which specifically lit up the lungs by using optical and molecular imaging techniques. Finally, given the ongoing COVID-19 pandemic, they showed that the ligand could also deliver a novel vaccine directly to the lungs and stimulate a local immune response, which could be more protective than currently existing vaccines that are injected into the arm.

    Daniela Staquicini, PhD, resident member of Rutgers Cancer Institute and assistant professor of the Division of Cancer Biology, Department of Radiation Oncology at Rutgers NJMS said, “this body of work actually encompasses an ensemble of three recently published manuscripts—including this one—on targeting different ZIP codes in the lung for multiple potential applications including non-invasive imaging and vaccine delivery, in which I had the privilege to serve as a co-first-author on behalf of several large teams of investigators.”

    Next, the team plans to focus on discovering more lipid vascular ZIP codes in the blood vessels that serve other organs and particularly tumors as a way to better target anti-cancer drugs and will work to further translate these discoveries into true clinical applications for patients.

    This work was recently published in the scientific journal, PNAS (10.1073/pnas.2220269120)

    A complete list of co-authors, funding, and disclosures is included in the paper here.

    About Rutgers Cancer Institute of New Jersey  As New Jersey’s only National Cancer Institute-designated Comprehensive Cancer Center, Rutgers Cancer Institute, together with RWJBarnabas Health, offers the most advanced cancer treatment options including bone marrow transplantation, proton therapy, CAR T-cell therapy and complex surgical procedures.  Along with clinical trials and novel therapeutics such as precision medicine and immunotherapy – many of which are not widely available – patients have access to these cutting-edge therapies at Rutgers Cancer Institute of New Jersey in New Brunswick, Rutgers Cancer Institute of New Jersey at University Hospital in Newark, as well as through RWJBarnabas Health facilities. To make a tax-deductible gift to support the Cancer Institute of New Jersey, call 848-932-8013 or visit www.cinj.org/giving. 

    [ad_2]

    Rutgers Cancer Institute of New Jersey

    Source link

  • How Breast Milk Boosts the Brain

    How Breast Milk Boosts the Brain

    [ad_1]

    Newswise — A new study by scientists at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University suggests that a micronutrient in human breast milk provides significant benefit to the developing brains of newborns, a finding that further illuminates the link between nutrition and brain health and could help improve infant formulas used in circumstances when breastfeeding isn’t possible.

    The study, published July 11 in the Proceedings of the National Academy of Sciences (PNAS),  also paves the way to study what role this micronutrient might play in the brain as we age.

    Researchers found that the micronutrient, a sugar molecule called myo-inositol, was most prominent in human breast milk during the first months of lactation, when neuronal connections termed synapses are forming rapidly in the infant brain. This was true regardless of the mother’s ethnicity or background; the researchers profiled and compared human milk samples collected across sites in Mexico City, Shanghai, and Cincinnati by the Global Exploration of Human Milk study, which included healthy mothers of term singleton infants.

    Further testing using rodent models as well as human neurons showed that myo-inositol increased both the size and number of synaptic connections between neurons in the developing brain, indicating stronger connectivity.

    “Forming and refining brain connectivity from birth is guided by genetic and environmental forces as well as by human experiences,” says Thomas Biederer, senior scientist on the Neuroscience and Aging Team at the HNRCA, senior author on the study, and faculty member at the Yale School of Medicine, where he leads a research group in the Department of Neurology.

    Diet is one of the environmental forces that offers many opportunities for study. In early infancy, the brain may be particularly sensitive to dietary factors because the blood-brain barrier is more permeable, and small molecules taken in as food can more easily pass from the blood to the brain.

    “As a neuroscientist, it’s intriguing to me how profound the effects of micronutrients are on the brain,” says Biederer. “It’s also amazing how complex and rich human breast milk is, and I now think it is conceivable that its composition is dynamically changing to support different stages of infant brain development.”

    Similar levels of myo-inositol across women in very different geographic locations point to its generally important role in human brain development, he observes.

    Research by others has shown that brain inositol levels decline over time as infants develop. In adults, lower than normal brain inositol levels have been found in patients with major depressive disorders and bipolar disease. Genetic alterations in myo-inositol transporters have been linked to schizophrenia. In contrast, in people with Down’s syndrome and patients with Alzheimer’s disease and Down’s syndrome, higher than normal accumulations of myo-inositol have been identified.

    “The current research does indicate that for circumstances where breastfeeding is not possible, it may be beneficial to increase the levels of myo-inositol in infant formula,” Biederer says.

    However, Biederer says it is too soon to recommend that adults consume more myo-inositol, which can be found in significant quantities in certain grains, beans, bran, citrus fruits, and cantaloupe (but which is not present in great quantities in cow’s milk). “We don’t know why inositol levels are lower in adults with certain psychiatric conditions, or higher in those with certain other diseases,” he says.

    A host of research questions remain: Are lower inositol levels in people with depression or bipolar disease a cause of those diseases, or a side effect of drugs used to treat them? Do higher than normal levels in people with Down’s syndrome and Alzheimer’s disease suggest that too much myo-inositol is problematic? What is the “right” level of myo-inositol to have in one’s brain for optimal brain health at various stages of life?

    “My colleagues at the HNRCA and I are now pursuing research to test how micronutrients like myo-inositol may impact cells and connectivity in the aging brain,” says Biederer. “We hope this work leads to a better understanding of how dietary factors interplay with age-related brain aberrations.”

    This work was supported by Reckitt Benckiser / Mead Johnson Nutrition and a gift from the Robert and Margaret Patricelli Family Foundation. Complete information on authors, funders, methodology, and conflicts of interest is available in the published paper.

    The content is solely the responsibility of the authors and does not necessarily represent the official views of Reckitt Benckiser / Mead Johnson Nutrition or the Robert and Margaret Patricelli Family Foundation.

    [ad_2]

    Tufts University

    Source link

  • Transcription Factors Contribute to Subtypes of Colorectal Cancers

    Transcription Factors Contribute to Subtypes of Colorectal Cancers

    [ad_1]

    Newswise — New research in colorectal cancers directed by investigators at the Johns Hopkins Kimmel Cancer Center suggests that expression of transcription factors — proteins that help turn specific genes on or off by binding to nearby DNA — may play a central role in the degree of DNA methylation across the genome, contributing to the development of different subtypes of these cancers. Methylation is a process in which certain chemical groups attach to areas of DNA that guide genes’ on/off switches. Studying the expression of these transcription factors in patients with colorectal cancers could reveal biomarkers to help determine overall survival in people with a subgroup of colorectal cancers who generally have better survival rates and, importantly, respond better to immune checkpoint therapy — a type of immunotherapy that releases restraints that cancer cells place on the immune response — and other treatments. Similar patterns of transcription factor expression could be seen by the researchers even in precancerous polyps, and could potentially be used by physicians to determine which patients need closer follow-up to prevent cancer development.

    A description of the work was published online July 24 in the journal Proceedings of the National Academy of Sciences.

    Aberrant DNA methylation is a well-known phenomenon occurring in cancers, explains senior study author Hariharan Easwaran, Ph.D., M.Sc., an associate professor of oncology at the Johns Hopkins Kimmel Cancer Center, but the degree of DNA methylation varies in cancers of the same tissue type. Some colon and other cancers have a very high degree of DNA methylation gains while others have much lower frequency of DNA methylation gains, he says. Traditionally, these have been described in an area of the genome known as a promoter region, which helps launch the transcription process. The exact mechanisms underlying these changes have not been clear.

    In a series of laboratory studies of genetic material taken from tubular adenomas (precancerous polyps in the colon) and colon tumors, the researchers linked cancer-specific transcription factor expression alterations to methylation alterations in colorectal cancers and their premalignant precursor lesions, which provided insights into the origins and evolution of different molecular subtypes of colorectal cancers.

    Specifically, researchers observed that some regions of the genome undergoing increased methylation tend to have binding sites for transcription factors that are downregulated, or have low expression. In some types of colon cancer, based on the types of genetic alterations associated with the cancer, transcription factors are upregulated or have higher expression.

    The findings suggest that cancer-specific methylation differences potentially evolve due to perturbation in the activity or expression of transcription factors. Similar changes in DNA methylation patterns were observed in precancerous polyps.

    “These studies highlight that the transcription factor expression changes and corresponding DNA methylation changes are early events during tumor development,” says lead study author Yuba Bhandari, Ph.D., a research associate at the Johns Hopkins Kimmel Cancer Center. “As polyps do not carry all of the key genetic changes typically found in full-blown cancer cells, the transcription factor changes may represent the earliest molecular regulators of precancerous cells, with profound impact on the genome-wide DNA methylation changes.”

    The specific set of transcription factors identified in the study may help in stratifying colorectal cancer prognosis, Easwaran adds.

    “This is particularly important, because multiple studies have shown that a certain subtype of colorectal cancers responds best to immune checkpoint blockade therapies, while others may not fare as well,” he says. “Expression profiling of relevant transcription factors may help develop better therapeutic strategies across subtypes of colorectal cancers.”

    Additional study co-authors included Rachael Powers, Sehej Parmar, Sara-Jayne Thursby, Ekta Gupta, Ozlem Kulak, Kurtis Bachman and Stephen Baylin of Johns Hopkins. Additional investigators from Janssen Research and Development in Pennsylvania and in Belgium contributed.

    The work was supported by the National Institutes of Health grants R01CA230995 and R01CA229240; National Institute of Environmental Health Sciences grant R01ES011858; National Cancer Institute grant R21CA212495; Sam Waxman Research Foundation and National Institute on Aging grant U01AG066101; Janssen Initiative; Commonwealth Grant; and Grollman Glick Scholarship.

    Baylin consults for MDxHealth. Methylation-specific PCR is licensed to MDxHealth in agreement with The Johns Hopkins University. Baylin and JHU are entitled to royalty shares received from sales. These arrangements have been reviewed and approved by The Johns Hopkins University in accordance with its conflict-of-interest policies.

    [ad_2]

    Johns Hopkins Medicine

    Source link

  • Fungus-Farming Ants Keep Gardens Healthy

    Fungus-Farming Ants Keep Gardens Healthy

    [ad_1]

    Newswise — ‘Weed early and often’ is the key to a productive garden. Interestingly, certain species of ants are also avid gardeners, a practice they’ve refined over 50 million years. They too weed their underground fungus gardens, but how they know what to weed out has been a mystery. Now, a multidisciplinary team of scientists report in PNAS on June 15 how ants distinguish the good fungus from the bad.

    People rely on sight to identify weeds but ants grow fungus underground in the dark and must have other ways to sense undesirable garden denizens. A team led by Jonathan Klassen, Ph.D., at the University of Connecticut and Marcy Balunas, Ph.D., at the University of Michigan has found that the ants sniff out diseased fungus by detecting chemicals called peptaibols.

    The team focused on the ant species Trachymyrmex septentrionalis whose habitat follows the pine barren ecosystem from Long Island all the way south to East Texas. Trachymyrmex ants grow their fungus below ground and feed it fresh organic detritus. The fungus acts almost like an external gut for the ant colony; the fungus grows up and around the fresh food laid on top of it in honeycomb shapes, produces digested food for the ants as it grows, and then secretes waste.

    Klassen Lab graduate student Katie Kyle, a co-first author on the paper, experimentally infected ant nests with Trichoderma, a naturally occurring, disease-causing fungus that infects the ants’ gardens and found that the ants began working overtime to remove the infection from the nests, increasing their waste output.

    Over the winter, while the ants were dormant, the team analyzed the fungal biomes of several different ant nests collected from different locations and found Trichoderma in all of them.

    Co-first author Sara Puckett, Ph.D., a recent graduate from the Balunas’ UConn lab, prepared extracts of Trichoderma containing the organic compounds of the fungus to determine if the weeding was triggered by one or more of these compounds or simply by the presence of the pathogen’s cells. 

    “We were curious to see if the ants were weeding because of compounds produced by the infecting fungus,” Balunas said.

    The team found the Trichoderma extract, when applied to the fungus garden, sent the ants into frenzied weeding activity just as actual Trichoderma infections had.

    Working with scientists from University of California, San Diego and University of North Carolina, Greensboro, they discovered the nests contained peptaibols, a family of compounds known to be produced by Trichoderma. However, finding which specific peptaibols were causing ant weeding proved more challenging since these extracts contained many compounds. 

    The researchers tested pure peptaibols, including two new compounds called trichokindins VIII and IX.

    It turns out that all the peptaibols tested caused some level of ant weeding, a finding that implies it may not be one particular peptaibol but rather that the whole suite of peptaibols can induce the ants to weed their garden. 

    “This suite of Trichoderma compounds inducing ant behavior is in contrast to many other natural products whose activity can often be attributed to one compound,” Balunas says.

    Although their data support peptaibols as a signal to weed, it’s not clear what exactly the ants are perceiving. It may be that the invading Trichoderma fungus produces the peptaibols and the ants detect them and then weed, note the researchers. Or perhaps the ants are detecting a secondary response from the fungus garden itself.

     The next step is to figure out those details of ant-fungus communication, Klassen says.

    “Maybe the fungus is signaling ‘I’m sick’. Maybe the fungus is detecting the peptaibols. We need to flesh out the chain of signaling,” Klassen says. 

    The findings highlight one of the few known systems where an animal responds to a disease of its beneficial symbiotic partner instead of a disease of its own body, a phenomenon that Balunas and Klassen are calling an extended defense response, and one that they look forward to continuing to tease apart.

    [ad_2]

    University of Connecticut

    Source link

  • Gender, Race Gaps in Democrats Voting: New Study

    Gender, Race Gaps in Democrats Voting: New Study

    [ad_1]

    Newswise — The enduring gender disparity in voting preferences between Democrats and Republicans stems, in part, from a greater percentage of female voters being Black and the historical trend of Black voters favoring the Democratic Party, as indicated by a recent study conducted by a group of sociologists.

    “The connection between gender and racial disparities in voting has been recognized for some time, but the exact interplay between the two has remained uncertain,” states Paula England, the Dean of Social Science at NYU Abu Dhabi and the primary author of the research published in the Proceedings of the National Academy of Sciences. “These discoveries highlight that approximately one-fourth of the gender gap in favoring the Democratic Party can be attributed to the fact that a larger proportion of female voters are Black compared to their male counterparts.”

    In every U.S. presidential election since 1980, women have consistently demonstrated a greater tendency to vote for the Democratic candidate compared to men. Importantly, prior studies have revealed that Black men face disproportionately higher rates of mortality, incarceration, and disenfranchisement resulting from criminal convictions. These disparities contribute to a reduced representation of Black men among the voting population, leading to a higher proportion of Black voters being women in relation to other racial groups.

    The study published in the Proceedings of the National Academy of Sciences (PNAS) aimed to enhance our understanding of the relationship between gender, race, and partisan voting disparities. The research team, comprising Michael Hout, a sociology professor at NYU, as well as NYU doctoral students Karyn Vilbig and Kevin Wells, conducted the study in order to shed light on the dynamics between gender and race as contributing factors to differences in voting preferences between political parties.

    To accomplish this, the authors of the study analyzed data from the General Social Survey (GSS) spanning the period from the 1980 to the 2016 presidential elections. Additionally, they replicated their analysis using data from the American National Election Surveys to ensure the robustness and consistency of their findings across different datasets. By utilizing these sources, the researchers aimed to provide a comprehensive understanding of the relationship between gender, race, and partisan voting gaps over several decades.

    The findings of their analysis revealed that the discrepancy in racial composition between genders accounted for 24% of the gender gap observed in favoring the Democratic Party. In simpler terms, since around 90% of Black voters tend to support Democrats, which is a considerably higher proportion compared to other demographic groups, the fact that a larger percentage of female voters are Black influences women’s voting preferences in favor of the Democratic Party.

    According to Paula England, a professor of sociology at NYU and the lead author of the study, while a gender gap in voting exists among White voters as well, approximately 25% of the total gender gap can be attributed solely to the variation in racial composition between male and female voters. This statement highlights the significant impact of racial demographics on the observed gender disparity in voting preferences.

    In order to eliminate the influence of another potential factor contributing to the gender gap, the researchers examined the role of income. Specifically, they focused on unmarried voters and investigated whether the higher likelihood of single women being economically disadvantaged compared to single men could explain why women tend to vote more Democratic.

    Interestingly, the study revealed that the gender gap in favoring the Democratic Party was particularly pronounced among unmarried individuals. It was observed that unmarried women, despite experiencing a higher poverty rate compared to unmarried men, displayed a stronger tendency to vote Democratic. However, the researchers also noted that although lower-income voters do exhibit a slightly higher inclination towards voting Democratic, the difference in voting preferences between lower-income and more affluent voters was not substantial. These findings suggest that while income disparities may contribute to the gender gap in voting, they do not fully account for the magnitude of the difference observed.

    The study’s authors reached the conclusion that no matter how they examined income and accounted for its influence, it had no mitigating effect on the gender gap in voting preferences. They highlighted the importance of the racial makeup of the voting population as a key factor contributing to this gap. These findings imply that although income disparities do contribute to the gap, they are not the exclusive explanation for the observed differences in voting preferences. The racial composition of the population significantly influences voting disparities as well.

     

    [ad_2]

    New York University

    Source link

  • Lung infection may be less transmissible than thought

    Lung infection may be less transmissible than thought

    [ad_1]

    Newswise — A little-known bacterium — a distant cousin of the microbes that cause tuberculosis and leprosy — is emerging as a public health threat capable of causing severe lung infections among vulnerable populations, those with compromised immunity or reduced lung function.

    Recent research found that various strains of the bacterium, Mycobacterium abscessus, were genetically similar, stoking fears that it was spreading from person to person.

    But a new study by Harvard Medical School researchers published May 22 in PNAS, calls those findings into question, offering an alternative explanation behind the genetic similarity of clinical clusters. This suggests that the pathogen may not be that prone to person-to-person transmission after all.

    “Our findings make a strong case for a different explanation behind the observed genetic similarities across strains,” said study senior author Maha Farhat, the Gilbert S. Omenn Associate Professor of Biomedical Informatics at HMS and a pulmonary disease expert at Massachusetts General Hospital. Farhat conducted the work in collaboration with Eric Rubin’s lab at the Harvard T.H. Chan School of Public Health.

    The results, Farhat added, argue against direct person-to-person transmission in clinical settings and instead point to M. abscessus infections being acquired from the home or other environmental exposures.

    In addition to having implications for the precautions that hospitals take to prevent outbreaks, it’s an important new clue into the behavior of a relatively unknown pathogen that poses serious risks for vulnerable populations.

    The research not only contributes to the understanding of M. abscessus transmission, but also suggests scientists should be cautious about assuming human transmission when they see genetic similarities in pathogens more generally, said study first author Nicoletta Commins, who conducted the research as a doctoral candidate at HMS and is now a postdoctoral fellow at the Broad Institute.

    “Our results certainly do not refute the possibility of person-to-person transmission of Mycobacterium abscessus in some cases, and more research is needed to inform best clinical practice for vulnerable patients,” she said. “However, our work supports a model in which person-to-person transmission may not be as common as it is sometimes suggested to be.”

    M. abscessus is a hardy microbe highly resistant to antibiotics and can infect the lungs of immunocompromised people. While it doesn’t pose a threat to most healthy individuals, it can cause severe infection in those with suppressed immunity or people with compromised lung function such as patients with cystic fibrosis, a genetic condition marked by recurrent lung infections and lung scarring. Notably, patients with CF who become infected with this organism become ineligible for lifesaving lung transplants.

    The earlier study that sounded the alarm about person-to-person transmission was based on genetic sequencing of M. abscessus samples obtained from cystic fibrosis patients at clinics in the United States, Australia, and Europe, including the United Kingdom. Researchers found few genetic mutations across the samples — a possible sign that the pathogen was spreading directly between humans.

    For many pathogens such as TB, for example, recent person-to-person transmission leads to only a few or no mutations between any pair of samples simply because the pathogen does not have much time to acquire genetic mutations, Farhat explained.

    “Understandably, observing the genetic similarity between M. abscessus samples caused a great deal of anxiety and fear around how these organisms could be transmitting,” she said.

    Clinicians, especially in clinics that treat cystic fibrosis patients, began taking extra precautions to avert transmission. However, follow-up investigations failed to find supporting evidence that human-to-human transmission was happening, raising questions about other possible explanations for the genetic similarities across samples.

    Farhat’s team set out to investigate a hypothesis that the samples appeared genetically similar because the pathogen was evolving at a very slow rate.

    “We thought, yeah, you observed a small number of mutations, but we don’t know how quickly these mutations are acquired, she explained. “It may be slower than we think, and links between samples that appear recent may not be.’”

    The scientists first used a large dataset of M. abscessus genomes to create a “tree of life,” a kind of genetic family tree for the bacterium.

    They looked at branches of the tree with clusters of genetically similar strains, then tried to calculate their evolutionary rate. They found that these genetically similar clusters were evolving around 10 times more slowly than typical M. abscessus strains.

    Next, they used computer modeling to determine whether the genetic similarities could be explained by the relatively small population size of these bacteria. But even when they simulated extreme population sizes, the result didn’t change. This was an indicator that the high genetic similarity is best explained by a slower evolutionary rate.

    Finally, researchers conducted experiments to see how fast different strains of M. abscessus evolved to develop resistance when exposed to antibiotics in the lab. They found that the genetically similar strains evolved much more slowly than other strains.

    “These are three separate lines of evidence supporting this idea that these clustered isolates of Mycobacterium abscessus are evolving at a slower rate,” Farhat said.

    In addition to reducing concern about person-to-person transmission, the findings provide new insight into a poorly understood pathogen.

    In particular, the results offer clues about how a bug found primarily in the environment adapts and changes after it enters the human body — information that could help scientists eventually understand how to prevent and treat infections.

    Farhat is now planning follow-up studies that would compare bacteria in the environment with samples taken from patients, to better understand why certain patients become infected.

    Authorship, funding, disclosures

    Additional authors included Mark R. Sullivan, Kerry McGowen

    Evan Koch, and Eric Rubin. The work was partly supported by the Damon Runyon Cancer Research Foundation, DRG-2415-20, with additional support from the Orchestra High Performance Compute Cluster at Harvard Medical School, funded by the NIH NCRR 1S10RR028832-01.

    [ad_2]

    Harvard Medical School

    Source link

  • Scientists Unveil Breakthrough for Cleaner Hydrogen Energy

    Scientists Unveil Breakthrough for Cleaner Hydrogen Energy

    [ad_1]

    Newswise — LAWRENCE — Chemists at the University of Kansas and U.S. Department of Energy’s Brookhaven National Laboratory have taken a big step toward splitting hydrogen and oxygen molecules to make pure hydrogen — without using fossil fuels.

    Results from pulse radiolysis experiments have laid bare the complete reaction mechanism for an important group of “water-splitting” catalysts. The KU and Brookhaven work means scientists are closer to making pure hydrogen from renewable energy, an energy source that could contribute to a greener future for the nation and world.

    Their findings appear this week in Proceedings of the National Academy of Sciences.

    “Understanding how the chemical reactions that make clean fuels like hydrogen work is very challenging — this paper represents the culmination of a project that I started in my very first year at KU,” said co-author James Blakemore, associate professor of chemistry, whose research in Lawrence forms the basis of the discovery.

    “Our paper presents data that were hard-won from specialized techniques to understand how a certain catalyst for hydrogen generation does the job,” he said. “The techniques that were used both here at KU and Brookhaven are quite specialized. Implementing these allowed us to get a full picture of how to make hydrogen from its constituent parts, protons and electrons.”

    Blakemore’s research at KU was the foundation of the breakthrough. He took his work to Brookhaven for research using pulse radiolysis, as well as other techniques, at their Accelerator Center for Energy Research. Brookhaven is one of only two places in the nation housing equipment that enables pulse radiolysis experiments.

    “It’s very rare that you can get a complete understanding of a full catalytic cycle,” said Brookhaven chemist Dmitry Polyansky, a co-author of the paper. “These reactions go through many steps, some of which are very fast and cannot be easily observed.”

    Blakemore and his collaborators made the discovery by studying a catalyst that is based on a pentamethylcyclopentadienyl rhodium complex, which is [Cp*Rh] for short. They focused on the Cp* (pronounced C-P-“star”) ligand paired with the rare metal rhodium because of hints from prior work showing that this combination would be suitable for the work.

    “Our rhodium system turned out to be a good target for the pulse radiolysis,” Blakemore said. “The Cp* ligands, as they’re called, are familiar to most organometallic chemists, and really chemists of all stripes. They’re used to support many catalysts and can stabilize a variety of species involved in catalytic cycles. One key finding of this paper gives fresh insight into how the Cp* ligand can be intimately involved in the chemistry of hydrogen evolution.”

    But Blakemore stressed the findings could lead to other improved chemical processes besides producing clean hydrogen.

    “In our work, we hope that chemists will see a study about how a common ligand, Cp*, can enable unusual reactivity,” the KU researcher said. “This unusual reactivity is relevant to the hydrogen story, but it’s actually bigger than this because Cp* is found in so many different catalysts. Chemists normally think of catalysts as being based on metals. In this way of thinking, if you’re making a new molecule, the metal is the key actor that brings the constituent parts together. Our paper shows that this isn’t always the case. Cp* can be involved in stitching the pieces together to form products.”

    Blakemore said he hoped this paper could be an opening that leads to improvements in other catalysts and systems that rely on Cp* ligands. The breakthrough, which was supported by the National Science Foundation and the DOE Office of Science, could apply more broadly to industrial chemistry. Blakemore is now working on applying techniques like those used in this work to the development of new approaches to recycling of nuclear fuels and handling of actinide species.

    KU students at the graduate and undergraduate levels also were involved in research that underpinned the breakthrough.

    “This project was a very important training vehicle for students,” Blakemore said. “Graduate student Wade Henke, the first author, is now at Argonne National Laboratory as a postdoc. Graduate student Yun Peng is the second author and kicked off the joint work with Brookhaven; both have now finished their Ph.D.s. Undergraduates also contributed to this project over the years, providing new complexes and insights that we used to frame the story that emerged in this paper.

    “All in all, I consider this a successful project and one that was a real team effort over the years.”

    [ad_2]

    University of Kansas

    Source link

  • Wealthy white homeowners more likely to see financial benefits from land conservation, study shows

    Wealthy white homeowners more likely to see financial benefits from land conservation, study shows

    [ad_1]

    Newswise — KINGSTON, R.I. – April 25, 2023 – Land conservation projects do more than preserve open space and natural ecosystems. They can also boost property values for homeowners living nearby. But a new study finds that those financial benefits are unequally distributed among demographic groups in the U.S.

    The study, by researchers from the University of Rhode Island and University of Illinois Urbana-Champaign, found that new housing wealth associated with land conservation goes disproportionately to people who are wealthy and white. In the state of Massachusetts, for example, white households in the top wealth quartile received 43% of the roughly $63 million housing wealth generated by new conservation from 1998 to 2016. That’s 140% more than would be expected under an equal demographic distribution, the researchers found. The trends found in Massachusetts hold generally over the rest of the U.S., the study showed.    

    “There’s a lot of economic inequality in the U.S. and we show that, unfortunately, conservation is adding to that,” said Corey Lang, a professor of environmental and natural resource economics at URI and a study coauthor. “That’s not to say that conservation is bad, or that we shouldn’t do it. Our primary purpose with this study was to document these disparities, and hopefully spark some debate about it.”

    The findings are published in the Proceedings for the National Academy of Sciences.

    The U.S. Forest Service estimates that about 6,000 acres of open space in the U.S. are cleared for development each day. But across the nation, organizations like municipal land trusts are working to set aside land, protecting it from future development in perpetuity. Over the past 35 years, over $80 billion in conservation funding have been approved by municipal referenda across the U.S., the researcher say.

    Those conservation efforts produce amenities that are attractive to homeowners. Conserved land provides peace and quiet, beautiful views, and recreation opportunities that are guaranteed for the foreseeable future. The value of those amenities is reflected in higher property values for people living in the vicinity.

    “Economists have studied this for a long time as a means of understanding how people value land conservation efforts, which can be fed into a cost-benefit analysis to see if new conservation efforts are justified,” Lang said. “We take a different approach in that we look at which homeowners are more likely to receive that bump in equity.”

    To do that, the researchers looked at detailed conservation records and anonymized demographic data for homeowners in Massachusetts. The team used an econometric model to estimate the extent to which land conserved between 1998 to 2016 added to the value of properties within a quarter mile of conservation areas. They found that each acre of conserved land increases the value of nearby homes by 0.018%. That means that a median-priced Massachusetts home located near 10 acres of conserved land gets a bump in value of around $659. That translates into roughly $62 million in conservation-related property wealth gains over the study period.

    Looking at the demographic breakdown of the homeowners who received that new wealth, the researchers found that 91% went to white homeowners, and 40% went to households in the highest wealth quartile. Roughly 43% went to households that were both white and in the highest wealth category—140% more than would be expected under an equal demographic distribution. In stark contrast, Black and Hispanic households in the lowest wealth quartile received only 6% of the benefits that would be expected under an equal distribution.

    The results aren’t necessarily attributable to any active or implicit discrimination on the part of conservation groups, the researchers say. The results can be shaped, for example, by several factors that yield patterns in where people live—with Black, Hispanic, and Asian households being less likely to own homes near conservation areas. Those patterns can emerge from racial and ethnic patterns of urban versus rural living in the state, and a paucity of conservable land in urban areas. There are also longstanding racial gaps in overall home ownership.

    Though the highly detailed data available for Massachusetts simply isn’t available for the rest of the U.S., the team performed an additional study to see if the Massachusetts trends likely hold across the country. They found that of the $9.8 billion in property wealth generated by conservation from 2001 to 2009 nationwide, 89% went to white households, 9% to Black and Hispanic households and 2% to Asian households.

    “Economists have done a lot to document disparities in exposure to pollution, but we know much less about equity in the distribution of the benefits from investments in valuable nature conservation,” said Amy Ando, a study coauthor who is a professor of environmental and natural resource economics at UIUC and University Fellow at the non-profit Resources for the Future. “These findings make clear there can be large environmental justice issues in who gains from the environmental goods we provide and protect, and may serve as a call for more research identifying other such inequities.”  

    Taken together, the researchers say, the results show that land conservation plays a role in maintaining wealth disparities across the U.S. While the researchers say they firmly advocate for land conservation efforts to continue, they don’t advocate any particular policy interventions to address the resulting inequity. They hope that the findings will broaden the conversation about land preservation to include issues related to distributional concerns.

    “I think more can be done to bring different groups to the table when decisions are made,” Lang said. “Making sure there’s a diversity of voices involved in these decisions is at least a start in addressing the problem that we’ve been able to document in this study.”

    The research was supported by the U.S. Department of Agriculture National Institute of Food and Agriculture (2018-67024-27695).

    [ad_2]

    University of Rhode Island

    Source link

  • Pioneering research sheds new light on the origins and composition of planet Mars

    Pioneering research sheds new light on the origins and composition of planet Mars

    [ad_1]

    Newswise — A new study has uncovered intriguing insights into the liquid core at the centre of Mars, furthering understanding of the planet’s formation and evolution.

    The research, led by the University of Bristol and published in the journal Proceedings of the National Academy of Sciences of the US, reveals the first-ever detections of sound waves travelling into the Martian core. Measurements from this acoustic energy, called seismic waves, indicate its liquid core is slightly denser and smaller than previously thought, and comprises a mixture of iron and numerous other elements.

    The findings are all the more remarkable, as the research mission was initially only scheduled to last for a little over one Mars year (two Earth years). Despite Martian storms hastening the accumulation of dust and reducing power to the NASA InSight Mars lander, NASA extended its stay, so geophysical data, including signals of marsquakes, continued to be gathered until the end of last year.

    Lead author Dr Jessica Irving, Senior Lecturer in Earth Sciences at the University of Bristol, said: “The extra mission time certainly paid off. We’ve made the very first observations of seismic waves travelling through the core of Mars. Two seismic signals, one from a very distant marsquake and one from a meteorite impact on the far side of the planet, have allowed us to probe the Martian core with seismic waves. We’ve effectively been listening for energy travelling through the heart of another planet, and now we’ve heard it.

    “These first measurements of the elastic properties of Mars’ core have helped us investigate its composition. Rather than being just a ball of iron, it also contains a large amount of sulfur, as well as other elements including a small amount of hydrogen.”

    The team of researchers used data from NASA’s InSight lander, a robotic spacecraft designed to probe the interior of Mars, to compare seismic waves travelling through the planet’s core with those transiting Mars’ shallower regions, and modelled properties of its interior.

    The InSight lander deployed a broadband seismometer on the Martian surface in 2018, allowing for the detection of seismic events, including marsquakes and meteorite impacts.  The multi-disciplinary team of scientists, including seismologists, geodynamicists and mineral physicists, used observations of two seismic events located in the opposite hemisphere from the seismometer to measure the travel times of seismic waves that passed through the core relative to seismic waves that remained in the mantle. 

    Dr Irving said: “So-called ‘farside’ events, meaning those on the opposite side of the planet to InSight, are intrinsically harder to detect because a great deal of energy is lost or diverted away as waves travel through the planet. We needed both luck and skill to find, and then use, these events. We detected no farside events in the first Martian year of operations. If the mission had ended then, this research couldn’t have happened.

    “The sol 976 marsquake was the most distant event found during the mission. The second farside event, S1000a – the first event detected on day 1,000 of operations – was particularly useful because it turned out to be a meteorite impact which we heard all the way through the planet, so we knew where the seismic signals came from. These events came after the Marsquake Service (MQS) had honed their skills on hundreds of days of Martian data; it then took a lot of seismological expertise from across the Insight Team to tease the signals out from the complex seismograms recorded by the lander.”  

    The authors used these measurements to build models describing physical properties of the core, including its size and elastic wave-speed. The results suggested Mars’ core is slightly denser and smaller than previous estimates, with a radius of approximately 1,780–1,810 km. These findings are consistent with the core having a relatively high fraction of light elements alloyed with iron, including abundant sulfur and smaller amounts of oxygen, carbon and hydrogen.

    Co-author Ved Lekic, Associate Professor of Geology at the University of Maryland College Park, in the US, said: “Detecting and understanding waves that travel through the very core of another planet is incredibly challenging, reflecting decades of efforts by hundreds of scientists and engineers from multiple countries. We not only had to utilise sophisticated seismic analysis techniques, but also deploy knowledge of how high pressures and temperatures affect properties of metal alloys, leveraging the expertise of the InSight Team.”

    Dr Irving added: “The new results are important for understanding how Mars’ formation and evolution differ from those of Earth. New theories about the formation conditions and building blocks of the red planet will need to be able to match the core’s physical properties as revealed by this new study.”

    Dr Jessica Irving and co-author Dr Anna Horleston, a seismologist from the University of Bristol, were supported with funding from the UK Space Agency.

    Paper

    ‘First observations of core-transiting seismic phases on Mars’ by Jessica Irving et al in PNAS 

    Image

    Sol 980: Instrument Context Camera (ICC) – NASA’s InSight Mars Lander

     

    [ad_2]

    University of Bristol

    Source link

  • Form Habits in No Time: No Magic Number!

    Form Habits in No Time: No Magic Number!

    [ad_1]

    Newswise — Putting on your workout clothes and getting to the gym can feel like a slog at first. Eventually, you might get in the habit of going to the gym and readily pop over to your Zumba class or for a run on the treadmill. A new study from social scientists at Caltech now shows how long it takes to form the gym habit: an average of about six months.

    The same study also looked at how long it takes health care workers to get in the habit of washing their hands: an average of a few weeks.

    “There is no magic number for habit formation,” says Anastasia Buyalskaya (PhD ’21), now an assistant professor of marketing at HEC Paris. Other authors of the study, which appears in the journal Proceedings of the National Academy of Sciences, include Caltech’s Colin Camerer, Robert Kirby Professor of Behavioral Economics and director and leadership chair of the T&C Chen Center for Social and Decision Neuroscience, and researchers from the University of Chicago and the University of Pennsylvania. Xiaomin Li (MS ’17, PhD ’21), formerly a graduate student and postdoctoral scholar at Caltech, is also an author.

    “You may have heard that it takes about 21 days to form a habit, but that estimate was not based on any science,” Camerer says. “Our works supports the idea that the speed of habit formation differs according to the behavior in question and a variety of other factors.”

    The study is the first to use machine learning tools to study habit formation. The researchers employed machine learning to analyze large data sets of tens of thousands of people who were either swiping their badges to enter their gym or washing their hands during hospital shifts. For the gym research, the researchers partnered with 24 Hour Fitness, and for the hand-washing research, they partnered with a company that used radio frequency identification (RFID) technology to monitor hand-washing in hospitals. The data sets tracked more than 30,000 gymgoers over four years and more than 3,000 hospital workers over nearly 100 shifts.

    “With machine learning, we can observe hundreds of context variables that may be predictive of behavioral execution,” explains Buyalskaya. “You don’t necessarily have to start with a hypothesis about a specific variable, as the machine learning does the work for us to find the relevant ones.”

    Machine learning also let the researchers study people over time in their natural environments; most previous studies were limited to participants filling out surveys.

    The study found that certain variables had no effect on gym habit formation, such as time of day. Other factors, such as one’s past behavior, did come into play. For instance, for 76 percent of gymgoers, the amount of time that had passed since a previous gym visit was an important predicator of whether the person would go again. In other words, the longer it had been since a gymgoer last went to the gym, the less likely they were to make a habit of it. Sixty-nine percent of the gymgoers were more likely to go to the gym on the same days of the week, with Monday and Tuesday being the most well attended.

    For the hand-washing part of the study, the researchers looked at data from health care workers who were given new requirements to wear RFID badges that recorded their hand-washing activity. “It is possible that some health workers already had the habit prior to us observing them, however we treat the introduction of the RFID technology as a ‘shock’ and assume that they may need to rebuild their habit from the moment they use the technology,” Buyalskaya says.

    “Overall, we are seeing that machine learning is a powerful tool to study human habits outside the lab,” Buyalskayasays.

    The study titled “What can machine learning teach us about habit formation? Evidence from exercise and hygiene” was funded by the Behavior Change for Good Initiative, the Ronald and Maxine Linde Institute of Economics and Management Sciences at Caltech, and the Tianqiao and Chrissy Chen Institute for Neuroscience at Caltech. 

    [ad_2]

    California Institute of Technology

    Source link

  • Feathered Dinosaurs & Feather-Feeding Beetles: A Long-Term Bond

    Feathered Dinosaurs & Feather-Feeding Beetles: A Long-Term Bond

    [ad_1]

    Newswise — New fossils in amber have revealed that beetles fed on the feathers of dinosaurs about 105 million years ago, showing a symbiotic relationship of one-sided or mutual benefit, according to an article published in Proceedings of the National Academy of Sciences of the United States of America today*. 

    The main amber fragments studied, from the Spanish locality of San Just (Teruel), contain larval moults of small beetle larvae tightly surrounded by portions of downy feathers. The feathers belonged to an unknown theropod dinosaur, either avian (a term referring to “birds” in wide sense) or non-avian, as both types of theropods lived during the Early Cretaceous and shared often indistinguishable feather types. However, the studied feathers did not belong to modern birds since the group appeared about 30 million years later in the fossil record, during the Late Cretaceous. 

    When looking at modern ecosystems, we see how ticks infest cattle, frogs capture insects with acrobatic tongues, or some barnacles grow on the skin of whales. These are just a few of the diverse and complex ecological relationships between vertebrates and arthropods, which have coexisted for more than 500 million years. The way that these two groups have interacted throughout deep time is thought to have critically shaped their evolutionary history, leading to coevolution. Nevertheless, evidence of arthropod-vertebrate relationships is extremely rare in the fossil record. 

    The larval moults preserved in the amber were identified as related to modern skin beetles, or dermestids. Dermestid beetles are infamous pests of stored products or dried museum collections, feeding on organic materials that are hard for other organisms to decay such as natural fibres. However, dermestids also play a key role in the recycling of organic matter in the natural environment, commonly inhabiting nests of birds and mammals, where feathers, hair, or skin accumulate. 

    “In our samples, some of the feather portions and other remains – including minute fossil faeces, or coprolites – are in intimate contact with the moults attributed to dermestid beetles and show occasional damage and/or signs of decay. This is hard evidence that the fossil beetles almost certainly fed on the feathers and that these were detached from its host,” explains Dr Enrique Peñalver, from the Geological and Mining Institute of Spain of the Spanish National Research Council (CN IGME-CSIC) and lead author of the study. 

    “The beetle larvae lived −feeding, defecating, moulting− in accumulated feathers on or close to a resin-producing tree, probably in a nest setting. A flow of resin serendipitously captured that association and preserved it for millions of years.” 

    “Three additional amber pieces each containing an isolated beetle moult of a different maturity stage but assigned to the same species were also studied, allowing a better understanding of these minute insects than what is usually possible in palaeontology,” says Dr David Peris, from the Botanical Institute of Barcelona (CSIC-Barcelona City Council) and co-author of the study. The most impressive, complete specimen was found in the amber deposit of Rábago/El Soplao in the northern Spain, roughly of the same age as San Just. 

    “It is unclear whether the feathered theropod host also benefitted from the beetle larvae feeding on its detached feathers in this plausible nest setting,” says Dr Ricardo Pérez-de la Fuente, from Oxford University Museum of Natural History and co-lead author of the study. “However, the theropod was most likely unharmed by the activity of the larvae since our data show these did not feed on living plumage and lacked defensive structures which among modern dermestids can irritate the skin of nest hosts, even killing them.” 

    ** 

    Notes 

    • The international and multidisciplinary team comprised researchers from the Geological and Mining Institute of Spain of the Spanish National Research Council (CN IGME-CSIC), the Botanical Institute of Barcelona (IBB-CSIC), the University of Barcelona and the Institute for Research on Biodiversity (IRBio), the Complutense University of Madrid, the ‘Parque de las Ciencias’ of Andalusia, the Autonomous University of Madrid, and the Royal Academy of Exact, Physical and Natural Sciences (Spain); the American Museum of Natural History and the Natural History Museum of Los Angeles County (United States of America); the Senckenberg Research Institute (Germany); and Oxford University Museum of Natural History (United Kingdom). 

    • Funding bodies: the project CRE, funded by the Spanish AEI/FEDER, UE Grant CGL2017-84419, the project PGC2018-094034-B-C22 (MCIU/AEI/FEDER, UE), the project CGL2014-52163, funded by the Spanish Ministry of Economy, Industry, and Competitiveness, the Secretary of Universities and Research of the Government of Catalonia and European Social Fund (2021FI_B2 00003), and the Consejería de Industria, Turismo, Innovación, Transporte y Comercio of the Gobierno de Cantabria through the public enterprise EL SOPLAO S.L. 

     

     

    About Oxford University Museum of Natural History   

    Founded in 1860 as the centre for scientific study at the University of Oxford, the Museum of Natural History now holds the University’s internationally significant collections of entomological, geological and zoological specimens. Housed in a stunning Pre-Raphaelite-inspired example of neo-Gothic architecture, the Museum’s growing collections underpin a broad programme of natural environment research, teaching and public engagement.  

    www.oumnh.ox.ac.uk  

    www.morethanadodo.com  

    [ad_2]

    University of Oxford

    Source link

  • How Will Farming Change in the Future?

    How Will Farming Change in the Future?

    [ad_1]

    Newswise — On November 15, 2022, the 8 billionth person on the planet was born. With concerns about food security on the rise, experts are asking: how will we feed everyone? Climate change, natural resource depletion, soil erosion, and fossil fuel use in farming make the task even more challenging. We need to do something differently, but what? 

    Barath Raghavan, an associate professor of computer science at USC Viterbi, is rethinking traditional farming practices by developing computational tools to help farmers design, develop, and manage sustainable farming methods.  Raghavan, a member of the California Rare Fruit Growers organization, currently grows more than 150 different edible plants in his yard. A decade ago, he started to combine his interests by researching how computing could make agriculture more sustainable.

    Raghavan calls this new area of research “computational agroecology,” uniting technology and farming expertise to develop diverse agricultural landscapes based on natural ecosystems. From crop selection to planting to irrigation, the method allows farmers to explore thousands of different potential designs to optimize food production without fossil fuel-derived pesticides.   

    “How can we design an ecosystem that is as productive and sustainable as a natural forest, but instead of producing food for wildlife, it’s producing food for people?” said Raghavan.  

    “It’s an incredibly hard problem because designing an ecosystem is a super complex, dynamic, natural system. We’re trying to build computing tools that can figure out how ecosystems work, so we can grow food plentifully and sustainably.”   

    “A totally new way to think about agriculture”

    In a new paper published in PNAS Nexus on March 16, Raghavan and his colleagues propose “a totally new way to think about agriculture and the benefits it can have for research and farming,” said Raghavan.  

    In this study, the researchers reconceptualize agriculture as a search through a “state space,” which represents all possible configurations of a system—in this context, agricultural land.  

    To better understand the concept of a state space, imagine a box of blocks: each block could be red, blue or yellow. The state space would consist of all the possible ways to arrange these blocks, such as all red, blue or green, or a combination of the three colors. 

    In the same way, a state space for an agricultural system might consist of all the possible variables that the system can take—such as crop or soil type, weather conditions, irrigation, fertilization or pest control.  

    This allows agricultural researchers and farmers to explore the different paths and strategies available—taking different “blocks” or variables and placing them together to see what works.  

    “Once we can conceive of a farm this way, we can then reframe many … farming planning questions.” Barath Raghavan. 

    Essentially, an agricultural “sandbox” to determine optimal configurations to increase crop yield, improve sustainability, and discover entirely new combinations of crops that grow well together. 

    For instance, the framework enables analytics and machine learning that could allow researchers to analyze the patterns between crop yield and soil moisture content or simulate growing different types of crops together for biodiversity.  

    “Once we can conceive of a farm this way, we can then reframe many research questions and farming planning questions as a search through the space of all possible states the farm could possibly end up in, with certain states being more desirable than others,” said Raghavan.  

    “This allows us to compare and contrast different approaches to farming, explore and combine techniques, and then search the state space in simulation for new farming techniques that have never been tried before and where trial and error in the real world would be far too expensive and time-consuming.”  

    “Playing a chess game with nature” 

    For example, in Southern California, farmers have recently discovered that high-quality coffee can grow plentifully between avocado trees. But figuring out the right way to do that, and maybe even add another couple of crops that work well together, is site specific.  

    “Each farmer doesn’t have the time or ability to do trial and error for years to figure out the right way to grow a half dozen crops on their land,” said Raghavan.

    “Instead, with the conceptual framework and eventually software framework of state spaces, a farmer could spell out an objective—such as diversified harvest with high yield and possible high profit for a specific piece of land—and have the system explore the state space and produce possible plant mixtures, placement, and management techniques that meet the farmer’s criteria.”  

    Raghavan compares the process to “playing a chess game with nature, but one that is both competitive and collaborative.”  

    “You’re making moves on the chessboard, which is your land, and nature is making moves too. Pests are going to eat one crop; a flood is going to damage another. What we are building is a computational framework that allows you to explore all the different ways that you might ‘play’ this game of chess with nature so that we can come up with the best one for your land.”  

    The group including Raghavan recently received a grant from the U.S. Department of Agriculture’s National Institute of Food and Agriculture for their research in this area. Now, the team is working through possible use cases with researchers and farmers to incorporate specific use cases and to develop software that can make it easy to simulate and explore state spaces.

    [ad_2]

    University of Southern California (USC)

    Source link

  • A gender perspective on the global migration of scholars – report

    A gender perspective on the global migration of scholars – report

    [ad_1]

    Newswise — International recognition is key to many successful academic careers, but research published today shows female scientific researchers are less internationally mobile than their male counterparts, although the gender gap has shrunk.

    Scientists tend to move from one country to another to advance their careers.  But  researchers from Oxford’s Leverhulme Centre for Demographic Science and the Max Planck Institute for Demographic Research in Germany, have found female researchers continue to be under-represented among internationally mobile researchers. In addition to moving less, female researchers also originate from and move to fewer countries, as well as migrating shorter distances, than their male counterparts.

    The study shows that gender inequality among mobile academic scientists varies across countries and over time on a global scale, and it reveals how it affects the demographic composition of the scientific workforce across the origin and the destination countries. The researchers provide a global and dynamic view on the global migration of scholars by gender.

    According to the paper, ‘While the US remained the leading academic destination worldwide, the shares of both female and male scholarly inflows to that country declined from around 25% to 20% over the study period, partially due to the growing relevance of China.’

    Lead author Xinyi Zhao, from the Leverhulme Centre and the Max Planck Institute adds, ‘Current literature points to gender inequality in science across countries. But a lack of relevant data on the migration of scholars has made it difficult to answer whether male and female scientists migrate equally.’

    Co-author Ridhi Kashyap  from Oxford’s Leverhulme Centre, says, ‘While gender inequalities remain, our findings support a growing feminisation of scholars migrating internationally. However, female researchers are still restricted in moving as globally and as freely as their male counterparts.’

    Gender gaps among researchers and international scholars favouring men were smaller in high-income and upper-middle income countries, than low-income countries. The US, UK, and Germany remained popular with female and male mobile scholars, but in these global hubs of international science, gender gaps nonetheless persisted.

    In a handful of countries such as Portugal, Brazil and Argentina, near gender equality among mobile researchers was seen. Others such as Japan and South Korea had significant gender gaps in favour of men.

    Co-author Emilio Zagheni, from the Max Planck Institute, concludes, ‘Our study indicates that opportunities for women to advance their academic careers through international mobility have increased. While we unveiled a key and welcome trend, we also note that more research is needed to understand underlying mechanisms, including the roles played by families and by science policies in shaping gender differences in the drivers and outcomes of relocations.’

    The team used bibliometric data on over 33 million scientific publications from Scopus, a global database of scholarly publications, to estimate the international migration of female and male researchers around the world from 1998 to 2017. This allowed the researchers to document and analyse cross-national trends in a systematic way.

    [ad_2]

    University of Oxford

    Source link

  • Discovery could lead to new fungicides to protect rice crops

    Discovery could lead to new fungicides to protect rice crops

    [ad_1]

    Newswise — A fungus that plagues rice crops worldwide gains entry to plant cells in a way that leaves it vulnerable to simple chemical blockers, a discovery that could lead to new fungicides to reduce the substantial annual losses of rice and other valuable cereals.

    Each year, blast disease, caused by the fungal pathogen Magnaporthe oryzae, attacks and kills plants that represent between 10% and 35% of the global rice crop, depending on weather conditions.

    University of California, Berkeley, biochemists led by Michael Marletta, professor of chemistry and of molecular and cell biology, discovered that the fungus secretes an enzyme that punches holes in the tough outer layer of rice leaves. Once inside, the fungus rapidly grows and inevitably kills the plant.

    In a paper published this week in the journal Proceedings of the National Academy of Sciences, Marletta and his colleagues describe the structure of the enzyme and how it works to help the fungus invade plants. Because the enzyme is secreted onto the surface of the rice leaf, a simple spray could be effective in destroying the enzyme’s ability to digest the wall of the plant. The scientists are now screening chemicals to find ones that block the enzyme.

    “The estimates are that if you could knock out this fungus, you could feed 60 million more people in the world,” said Marletta, the Choh Hao and Annie Li Chair in the Molecular Biology of Diseases at UC Berkeley. “This enzyme is a unique target. Our hope here is that we’ll screen to find some unique chemicals and spin out a company to develop inhibitors for this enzyme.”

    This target is one of a family of enzymes called polysaccharide monooxygenases (PMO) that Marletta and his UC Berkeley colleagues discovered a little over 10 years ago in another, more widespread fungus, Neurospora. Polysaccharides are sugar polymers that include starch as well as the tough fibers that make plants sturdy, including cellulose and lignin. The PMO enzyme breaks cellulose into smaller pieces, making the polysaccharide susceptible to other enzymes, such as cellulases, and speeding up the breakdown of plant fibers.

    “There is an urgent need for more sustainable control strategies for rice blast disease, particularly in South Asia and sub-Saharan Africa,” said Nicholas Talbot, who is Marletta’s colleague and co-author, a plant disease expert and executive director of The Sainsbury Laboratory in Norwich in the United Kingdom. “Given the importance of the polysaccharide monooxygenase to plant infection, it may be a valuable target for developing new chemistries that could be applied at much lower doses than existing fungicides and with less potential environmental impact. It might also be a target for completely chemical-free approaches, too, such as gene silencing.”

    Marletta and UC Berkeley Ph.D students Will Beeson and Chris Phillips were originally interested in these enzymes because they degrade plant cellulose much more quickly than other previously described enzymes and thus had potential to turn biomass into sugar polymers that can be fermented more readily into biofuels. Fungi use PMOs to provide a source of food.

    He and UC Berkeley colleagues subsequently found hints that some fungal PMOs may do more than merely turn cellulose into food. These PMOs were turned on in the early stages of infection, implying that they’re important in the infection process rather than providing food.

    That’s what Marletta, Talbot and their colleagues found. Led by postdoctoral fellow Alejandra Martinez-D’Alto, the UC Berkeley scientists biochemically characterized this unique PMO, called MoPMO9A, while Talbot and UC Berkeley postdoctoral fellow Xia Yan showed that knocking out the enzyme reduced infection in rice plants.

    Marletta and his UC Berkeley colleagues have found similar PMOs in fungi that attack grapes, tomatoes, lettuce and other major crops, which means the new findings may have broad application against plant fungal diseases.

    “It isn’t just rice that small molecule inhibitors could be used against. They could be widely used against a variety of different crop pathogens,” Marletta said. “I think the future for this, in terms of drug development for plant pathogens, is pretty exciting, which is why we are going to pursue both the fundamental science of it, like we always do, and try to put together pieces to spin it out as a company.”

    Biofuels lead way to attacking fungal pathogen

    Marletta specializes in identifying and studying new and unusual enzymes in human cells. But 10 years ago, when people got excited about biofuels as a way to address climate change, he was awarded a grant from UC Berkeley’s Energy Biosciences Institute to search for enzymes in other life forms that digest plant cellulose faster than the enzymes known at the time. The goal was to turn tough cellulose fibers into short-chain polysaccharides that yeast could ferment into fuel.

    “I said to two of my first-year graduate students, Chris Phillips and Will Beeson, ‘You know, there’s got to be organisms out there that eat cellulose fast,’” Marletta said. “Those are the ones we want to find, because we know the enzymes that eat it slow, and they’re not particularly useful in a biotechnology sense because they’re slow.”

    Phillips and Beeson succeeded in finding fast-acting enzymes in a common fungus, Neurospora, which is among the first fungi to attack dead trees after a fire and does a quick job of digesting wood for nutrients. They isolated the enzyme responsible, the first known PMO, and described how it worked. Since then, Marletta’s students have identified 16,000 varieties of PMO, most in fungi, but some in wood-eating bacteria. To date, these have had some success in speeding the production of biofuels as part of a cocktail of other enzymes, though they haven’t made biofuels competitive with other fuels.

    But Marletta was intrigued by a small subset of these 16,000 varieties that seemed to do more than provide nutrition for fungi. MoPMO9A, in particular, had an amino acid segment that binds to chitin, a polysaccharide that forms the outer coat of fungi, but is not found in rice. And though all PMOs are secreted, MoPMO9A was secreted during the infectious cycle of the fungus.

    Studies subsequently showed that Magnaporthe concentrates MoPMO9A in a pressurized infection cell, called the appressorium, from which it is secreted onto the plant, with one portion of the enzyme binding to the outside of the fungus. The other end of the enzyme has a copper atom embedded in its center. When the fungus slaps the loose end of the enzyme onto the rice leaf, the copper atom catalyzes a reaction with oxygen to break cellulose fibers, helping the fungus breach the leaf surface and invade the entire leaf.

    “We were curious: ‘Hey, why does this enzyme have a chitin-binding domain if it’s supposed to be working on cellulose?’” according to Marletta. “And that’s when we thought, ‘Well, maybe it’s secreted, but it sticks to the fungus. That way, when the fungus is sitting on the plant, it can have between it and the leaf the catalytic domain to punch the hole into the leaf.’”

    That proved to be the case. Marletta and Talbot are now testing other pathogens that produce PMOs to see if they use the same trick to enter and infect leaves. If so — Marletta is confident that they do — it opens avenues to attack them with a spray-on fungicide, as well.

    “The only place you find PMOs like this is in plant pathogens that have to gain access to their host. So, they’re almost certainly going to be working the same way,” Marletta said. “I think the scope of work to develop inhibitors to this particular PMO is going to be well beyond rice, even though that itself is pretty important. We’re going to be able to use them in other important crop plants.”

    Other co-authors of the paper are Alejandra Martinez-D’Alto, Tyler Detomasi, Richard Sayler and William Thomas of UC Berkeley. Marletta is a member of the Berkeley branch of the California Institute for Quantitative Biosciences (QB3). The research was funded by the National Science Foundation (CHE-1904540, MCB-1818283) and the National Institutes of Health (F32-GM143897).

    [ad_2]

    University of California, Berkeley

    Source link

  • “It’s me!” fish recognizes itself in photographs

    “It’s me!” fish recognizes itself in photographs

    [ad_1]

    Newswise — A research team led by Specially Appointed Professor Masanori Kohda from the Graduate School of Science at the Osaka Metropolitan University has demonstrated that fish think “it’s me” when they see themselves in a picture, for the first time in animals. The researchers found that the determining factor was not seeing their own body but seeing their face. These findings have been published in the Proceedings of the National Academy of Sciences.

    In this study, relevant experiments were conducted with Labroides dimidiatus, commonly known as a cleaner fish, which are known to be able to recognize themselves in mirrors and regularly attack other unfamiliar cleaner fish who intrude on their territory. Each cleaner fish was presented with four photographs: a photo of themselves; a photo of an unfamiliar cleaner; a photo of their own face on an unfamiliar cleaner’s body; and a photo of unfamiliar cleaner’s face on their own body. Interestingly, the cleaner fish did not attack photos with their own faces but did attack those with the faces of unfamiliar cleaner fish. Together these results indicate that the cleaner fish determined who was in the photograph based on the face in the photo but not the body in the similar way humans do.

    To negate the possibility that the fish considered photographs of themselves as very close companions, a photograph mark-test was conducted. Fish were presented with a photograph where a parasite-like mark was placed on their throat. Six of the eight individuals that saw the photograph of themselves with a parasite mark were observed to rub their throats to clean it off. While showing those same fish pictures of themselves without parasite marks or of a familiar cleaner fish with parasite marks did not cause them to rub their throats.

    “This study is the first to demonstrate that fish have an internal sense of self. Since the target animal is a fish, this finding suggests that nearly all social vertebrates also have this higher sense of self,” stated Professor Kohda.

    ###

    About OMU

    Osaka Metropolitan University is a new public university established by a merger between Osaka City University and Osaka Prefecture University in April 2022. For more science news, see https://www.omu.ac.jp/en/, and follow @OsakaMetUniv_en and #OMUScience.

    [ad_2]

    Osaka Metropolitan University

    Source link

  • Free speech vs. harmful misinformation: How people resolve dilemmas in online content moderation

    Free speech vs. harmful misinformation: How people resolve dilemmas in online content moderation

    [ad_1]

    Newswise — The issue of content moderation on social media platforms came into sharp focus in 2021, when major platforms such as Facebook and Twitter suspended the accounts of then U.S. President Donald Trump. Debates continued as platforms confronted dangerous misinformation about the COVID-19 and the vaccines, and after Elon Musk singlehandedly overturned Twitter’s COVID-19 misinformation policy and reinstated previously suspended accounts.

    “So far, social media platforms have been the ones making key decisions on moderating misinformation, which effectively puts them in the position of arbiters of free speech. Moreover, discussions about online content moderation often run hot, but are largely uninformed by empirical evidence,” says lead author of the study Anastasia Kozyreva, Research Scientist at the Max Planck Institute for Human Development. “To deal adequately with conflicts between free speech and harmful misinformation, we need to know how people handle various forms of moral dilemmas when making decisions about content moderation,” adds Ralph Hertwig, Director at the Center for Adaptive Rationality of the Max Planck Institute for Human Development.

    In the conjoint survey experiment, more than 2,500 U.S. respondents indicated whether they would remove social media posts spreading misinformation about democratic elections, vaccinations, the Holocaust, and climate change. They were also asked whether they would take punitive action against the accounts by issuing a warning or a temporary or indefinite suspension. Respondents were shown information about hypothetical accounts, including political leaning and number of followers, as well as the accounts’ posts and the consequences of the misinformation they contained.

    The majority of respondents chose to take some action to prevent the spread of harmful misinformation. On average, 66 percent of respondents said they would delete the offending posts, and 78 percent would take some action against the account (of which 33 percent opted to “issue a warning” and 45 percent chose to indefinitely or temporarily suspend accounts spreading misinformation). Not all misinformation was penalized equally: Climate change denial was acted on the least (58%), whereas Holocaust denial (71%) and election denial (69%) were acted on most often, closely followed by anti-vaccination content (66%).

    “Our results show that so-called free-speech absolutists such as Elon Musk are out of touch with public opinion. People by and large recognize that there should be limits to free speech, namely, when it can cause harm, and that content removal or even deplatforming can be appropriate in extreme circumstances, such as Holocaust denial,” says co-author Stephan Lewandowsky, Chair in Cognitive Psychology at the University of Bristol.

    The study also sheds light on the factors that affect people’s decisions regarding content moderation online. The topic, the severity of the consequences of the misinformation, and whether it was a repeat offense had the strongest impact on decisions to remove posts and suspend accounts. Characteristics of the account itself—the person behind the account, their partisanship, and number of followers—had little to no effect on respondents’ decisions. 

    Respondents were not more inclined to remove posts from an account with an opposing political stance, nor were they more likely to suspend accounts that did not match their political preferences. However, Republicans and Democrats tended to take different approaches to resolving the dilemma between protecting free speech and removing potentially harmful misinformation. Democrats preferred to prevent dangerous misinformation across all four scenarios, whereas Republicans preferred to protect free speech, imposing fewer restrictions.

    “We hope our research can inform the design of transparent rules for content moderation of harmful misinformation. People’s preferences are not the only benchmark for making important trade-offs on content moderation, but ignoring the fact that there is support for taking action against misinformation and the accounts that publish it risks undermining the public’s trust in content moderation policies and regulations,” says co-author Professor Jason Reifler from the University of Exeter. “Effective and meaningful platform regulation requires not only clear and transparent rules for content moderation, but general acceptance of the rules as legitimate constraints on the fundamental right to free expression. This important research goes a long way to informing policy makers about what is and, more importantly, what is not acceptable user-generated content,” adds co-author Professor Mark Leiser from the Vrije Universiteit Amsterdam.

    [ad_2]

    Max Planck Institute for Human Development

    Source link

  • Notre Dame study finds voter ID laws mobilize voters in both parties, rather than sway election results

    Notre Dame study finds voter ID laws mobilize voters in both parties, rather than sway election results

    [ad_1]

    Newswise — In the past two decades, many state governments have enacted voter identification requirements for constituents voting in their state, requiring a photo ID or other significant proof to access a ballot. These laws were intended to prevent voter fraud and increase election security, but they also sparked national debate over whether they disenfranchised disadvantaged groups such as people living in poverty or people of color, who may not have a valid ID nor be able to obtain one. 

    Many argued that implementing the ID requirements gave Republicans the electoral advantage while harming Democrats, whose supporters were more likely to be affected by the laws. Up until now, the extent to which these laws provided electoral benefits for Republican candidates and/or disadvantages for Democratic ones had not been considered. 

    In a study recently published in the Proceedings of the National Academy of Sciences, Jeffrey Harden, the Andrew J. McKenna Family Associate Professor in the Department of Political Science and concurrent associate professor in the Department of Applied and Computational Mathematics and Statistics, and Alejandra Campos, a third-year graduate student in the political science doctorate program, both at the University of Notre Dame, found that voter ID requirements motivated supporters of both parties equally to comply and participate, but had little overall effect on the actual outcomes of the elections.

    “We addressed a very simple question of whether or not these laws actually have the sort of electoral effects that people seem to think they do,” Harden said. “It was surprising to us to see that no one had really addressed that question yet.”

    The two researchers examined the effect of voter ID laws on the electoral results for significant political races at the state level (state legislatures and governorships) and federal level (U.S. Congress and president) from 2003 to 2020. The framework of the study was to find out whether a voter ID requirement affected the vote share advantage of Republican or Democratic candidates in these races. The assumption, Harden explained, is that because Democratic voters tend to be the ones who are more impacted by voter ID requirements, it is in the Democratic Party’s interest to push back against these laws and in the Republican Party’s interest to advocate for them. 

    “This suggests that one party’s candidates would benefit more, and one party’s candidates would be penalized more, by these laws,” Harden theorized. “But that’s not really what’s going on here — the long-term implications of voter ID are more nuanced than that.” 

    Rather, the researchers speculated, voter ID laws had a countermobilization effect by creating a complex series of events, happening over the course of the campaign, that resulted in supporters of both parties getting motivated and mobilized, which ultimately diminished the laws’ anticipated effects on the actual election results.

    “The parties had to take additional steps to counteract these laws,” Campos explained. “The Democratic Party, for example, mobilized their constituents to meet the ID requirements so the laws would not impact their electoral fortunes.”

    Other implications include the idea that ID requirements frustrated Democrats and enthused Republicans — motivating both groups’ supporters to vote. In addition, the researchers wrote, voters may have become accustomed to adhering to the laws, thus softening their controversial stigma in the public’s opinion and eventually reducing their effects.

    “Any impact these laws exert on voter access occurs concurrently with their effects on other elements of the electoral process,” the researchers pointed out. “What we find out, in the end, is that the results get washed out to the point where these voter ID laws don’t have much of an impact on the actual electoral outcomes.”

    With existing research pointing to the fact that voter ID laws don’t necessarily impact voter fraud or voter turnout, and Harden’s and Campos’ research indicating that they don’t have much of an effect on election results, Harden suggested we ask ourselves: “How difficult should it be in a democratic society for a person to vote?” 

    “We think this should be a part of the discussion,” both researchers said. “Future election policy may benefit from a shift in the debate.” Instead of focusing on which is more important — voting security or access — lawmakers should consider what is the minimum amount of voter responsibility required to vote, the researchers said, rather than setting up barriers to voting not supported by evidence.

    “We need to ask ourselves: Why are we doing this?” Campos noted. “We need to think seriously about the consequences of these laws and whether or not there’s any benefit to them at all.”

    Harden noted the importance of studying democratic institutions and the way in which democracy can ebb and flow within a country — and how this practice fits in ideally with the mission of Notre Dame. 

    “What we’re talking about here are reforms that make a fundamentally democratic practice (i.e., voting) more or less difficult for people,” Harden said. “Being at a university committed to truth and the common good, we need to understand if this significant reform is doing what people expect it to when they enact that reform.”

    [ad_2]

    University of Notre Dame

    Source link

  • Decades-old crustaceans coaxed from lake mud give up genetic secrets revealing evolution in action

    Decades-old crustaceans coaxed from lake mud give up genetic secrets revealing evolution in action

    [ad_1]

    Newswise — Human actions are changing the environment at an unprecedented rate. Plant and animal populations must try to keep up with these human-accelerated changes, often by trying to rapidly evolve tolerance to changing conditions.

    University of Oklahoma researchers Lawrence Weider, professor of biology, and Matthew Wersebe, a biology doctoral candidate, demonstrated rapid evolution in action by sequencing the genomes of a population of Daphnia pulicaria, an aquatic crustacean, from a polluted lake.  

    The research, which was conducted as part of Wersebe’s doctoral dissertation, was recently published in the Proceedings of the National Academy of Sciences.  Wersebe and Weider revived decades-old Daphnia resting eggs from lake sediments, a method known as resurrection ecology, which has been refined in Weider’s lab over the past several decades. They then sequenced the entire genomes of 54 different Daphnia individuals from different points-in-time, allowing them to study the genetics and evolution of the population.

    The Daphnia were collected from Tanners Lake, located in Oakdale, Minnesota. Tanners Lake has suffered significant salt pollution, stemming from the widespread use of road deicing salts in its watershed.  

    Daphnia, also known as water fleas, play critical roles in environmental monitoring. For example, they have served as important test organisms in laboratories around the world for over a century because of their sensitivity to many environmental stressors such as chemicals. In nature, Daphnia act as a keystone species in freshwater food webs globally, where they feed on algae to help keep lake and reservoir water clean and serve as a food item for recreational and commercially important fish species.

    Wersebe’s and Weider’s results indicate that rapid adaptation to salt pollution may allow lake Daphnia to persist in the face of anthropogenic salinization, maintaining the food webs and ecosystem services that Daphnia support. However, the ability of these populations to adapt will depend on the speed at which these changes are occurring and the underlying genetic makeup of the impacted populations. 

    Over the past several years, many researchers have published results defining the scope and scale of lake salinization and recent research has highlighted the ecological impacts. However, to date, the evolutionary implications are not well known. Through their study, Wersebe and Weider reported signatures of natural selection throughout the genome near genes related to osmoregulation and ion regulation, key processes for dealing with high salt. Characterizing clones for salinity tolerance revealed evidence that genetic changes may underlie rapid evolution.  

    “Work like this is the first step in designing future studies incorporating recent technological advances, such as CRISPR gene editing, allowing the creation of comprehensive genotype-to-phenotype maps and predicting the role that genetic variation plays in creating diverse forms and functions,” Wersebe said. “In fact, we found a promising gene that appears not to work properly in the older Daphnia, but a functional copy of the gene is increasing in frequency – true evolution in action.”

    Future research using these advanced technologies for cutting and pasting the non-functional gene into Daphnia would be one way to better probe the effects that mutations have on complex phenotypic traits like salinity tolerance.  

    The work was funded by the OU Department of Biology Adams Summer Scholarship, Robberson OU Graduate College Grant, Hill Fund for Research in Biology, OU Graduate Student Senate Research Grant, American Museum of Natural History Theodore Roosevelt Grant and the National Science Foundation Biogeography of Behavior student seed grant awarded to Wersebe in support of graduate research. The study was facilitated by material and technical assistance from the University of Oklahoma Biological Station in Kingston, Oklahoma, and the St. Croix Watershed Research Station in Marine-on-St. Croix, Minnesota.  

    [ad_2]

    University of Oklahoma

    Source link

  • Harmful bacteria can elude predators when in mixed colonies

    Harmful bacteria can elude predators when in mixed colonies

    [ad_1]

    Newswise — Efforts to fight disease-causing bacteria by harnessing their natural predators could be undermined when multiple species occupy the same space, according to a study by Dartmouth College researchers.

    When growing in mixed colonies, some harmful bacteria may be able to withstand attacks from the bacteria and viruses that target them by finding protection inside groups of rival species, according to a report published in the Proceedings of the National Academy of Sciences (PNAS).

    The researchers found that the intestinal bacterium Escherichia coli became surrounded by tightly packed colonies of Vibrio cholerae — which causes the deadly disease cholera — when the species were grown together. These clusters protected E. coli from the bacteria Bdellovibrio bacteriovorus that preys on both species individually, but in the study could only kill the outer layer of V. cholerae. This left the unscathed cells of E. coli and V. cholerae insulated within the colonies free to multiply.

    The findings add a new layer of complication to the development of biological antimicrobials, wherein bacteria-killing bacteria or viruses — known as bacteriophages — are deployed to fight infections, said corresponding author Carey Nadell, an assistant professor of biological sciences at Dartmouth College. These organisms can be more effective than antibiotics at penetrating bacterial colonies, or biofilms, and have emerged as a possible supplement or alternative to antibiotics. Bacteria worldwide have become more resistant to antibiotics due to the drugs’ overuse.

    Most research on predatory bacteria and phages, however, has focused on liquid cultures or single-species biofilms, Nadell said. The Dartmouth study shows that the interactions between multiple bacterial species — which are more common in real life — can be difficult to predict from studying species in isolation. , Nadell and coauthors Benjamin Wucher and James Winans, Ph.D. candidates in biological sciences at Dartmouth,In a related study published in the journal PLoS Biology in December found that E. coli also could avoid the bacteriophage T7 when embedded in groups of V. cholerae.

    “There were certain elements of our experiments that are closer to real life — a lot of infections are caused by bacteria living with other bacteria in a biofilm. They’re like a forest — they’re little ecosystems,” Nadell said.

    “For E. coli, if it grew with V. cholerae, it could do better than on its own, but V. cholerae did worse. It’s fascinating that growing together had opposite effects on each species’ chances of survival,” he said. “Our research shows that the way prey populations can resist or not resist predators can be very different in multispecies conditions. The efficacy of bacteriophages and predatory bacteria to kill off harmful bacteria might depend on the other species their prey are living with, and on the biofilm structures they produce alone versus together.”

    In the PNAS study, the protection afforded E. coli depended on how close the two bacteria were when they began growing. When sparsely populated, V. cholerae had ample room to form into tightly packed colonies that would encase E. coli, which does not grow as densely.

    But when both species started out close together, E. coli prevented V. cholerae from producing its normal group structure. This disruption caused both species to become more vulnerable to death by B. bacteriovorus.

    “When we put these species together, we observed biofilm properties we could not really predict from each alone that would have direct implications on the use of phages and predatory bacteria to kill them,” Nadell said. “Our work highlights the importance of studying other examples of multispecies biofilm structures. We feel confident that what we saw will apply to other cases, but it’s a question of when and to what extent.”

    The paper, “Breakdown of Clonal Cooperative Architecture in Multispecies Biofilms and the Spatial Ecology of Predation,” was published online by the Proceedings of the National Academy of Sciences DATE. The work was supported by the National Science Foundation (IOS 2017879 and MCB 1817352), the Simons Foundation (826672), the Human Frontier Science Program (RGY0077/2020), and a Gillman Fellowship and GAANN Fellowship from the Dartmouth College Department of Biological Sciences.

    [ad_2]

    Dartmouth College

    Source link