Culture

Thrive announces clinical data from study of blood test to detect multiple cancers

Thrive Earlier Detection Corp., a company dedicated to extending and saving lives by incorporating earlier cancer detection into routine medical care, together with Johns Hopkins University and Geisinger Health, today announced data from the landmark DETECT-A study. DETECT-A (Detecting cancers Earlier Through Elective mutation-based blood Collection and Testing) is the first ever prospective, interventional study to use a blood test to screen for multiple types of cancers in a real-world population. The study was conducted by Johns Hopkins University and Geisinger and enrolled more than 10,000 women with no prior history of cancer. The purpose was to identify multiple cancer types in asymptomatic individuals using an early version of CancerSEEK developed in 2016 ("Thrive's blood test"). DETECT-A is the first study of a multi-cancer blood-based screening test to deliver results to physicians to manage patient care.

Cancer is the second leading cause of death in the United States with an estimated 600,000 people expected to die from the disease this year. Most of these cancers are often detected too late, and only after people start to experience symptoms. These "symptom-detected" cancers too frequently coincide with late stage, metastatic disease, and result in poor outcomes. However, when cancer is detected through screening, or are "screen-detected," the disease is often identified earlier when it can be more effectively treated, and in many cases even cured. Unfortunately, current standard-of-care screening tests, like mammography and colonoscopy, only detect less than 30% of all incident cancers. The DETECT-A study provides the first real-world evidence that we can significantly shift the paradigm from "symptom-detected" cancers to more "screen-detected" cancers via a multi-cancer blood-based test.

The key findings from this prospective, interventional study demonstrate the following:

Thrive's blood test identified cancers in individuals without any history of the disease.

Thrive's blood test more than doubled the number of cancers that were first "screen-detected." 25% of the women who were diagnosed with cancer were identified by current standard-of-care tests. By incorporating Thrive's blood test, the percentage of "screen-detected" cancers increased from 25% to 52%.

Thrive's blood test identified cancers across 10 different organs, seven of which currently have no standard-of-care screening.

Thrive's blood test can identify cancers prior to clinically evident metastasis. 65% of the cancers identified were localized or regional.

Thrive's blood test is additive and complementary to standard-of-care and was incorporated into routine medical care without discouraging patients from engaging in other forms of screening.

Thrive's blood test, in combination with imaging, minimized false positive results with 99.6% specificity.

The study's workflow (blood test plus imaging) safely guided clinical follow-up in blood test-positive participants with zero adverse events.

"This study is a seminal moment in cancer screening that advances the entire field," said Christoph Lengauer, Ph.D., co-founder and chief innovation officer of Thrive. "For the first time, a blood test was utilized in a real-world setting and was able to more than double the number of cancers first identified through screening methods. We learned that it can be both complementary to existing standard-of-care screening tools, and a significant benefit for many types of cancers like ovarian, appendix and kidney, which do not have any current screening modalities."

These data were published in Science and were presented today during the clinical plenary: Early Detection and CtDNA at the American Association for Cancer Research (AACR) Virtual Annual Meeting.

Prospective Interventional Study Design

The ability to identify multiple types of cancers through a blood draw is one of the most exciting advances in cancer diagnostics; however, prospective, interventional studies like DETECT-A are imperative to understand if a test can work in the real world. To date, retrospective and observational studies of blood-based multi-cancer tests have curated samples from participants who were already known to have cancer at the time of testing. Conversely, in DETECT-A, a prospective interventional study, participants were unaware of cancer at the time of enrollment and test results were reported to physicians and guided intervention.

DETECT-A enrolled 10,006 women with no prior history of cancer in a population with high adherence to standard-of-care cancer screening tests, such as mammography and colonoscopy. All participants were enrolled through the Geisinger Health System, enabling access to electronic medical records of participating individuals and minimizing loss to follow up.

DETECT-A utilized an early version of CancerSEEK that was developed in 2016, and analyzes 16 genes and nine proteins causatively linked to multiple types of cancer. Screening began with the analysis of a blood sample to identify potential abnormal values for at least one biomarker. Those with abnormal values were invited back for a confirmatory test to determine whether the identical biomarker was persistently abnormal and if appropriate, the individual was reviewed by a Multidisciplinary Review Committee. If a non-cancerous cause for the abnormal biomarker could not be identified, imaging was ordered. Patients with concerning imaging findings were referred to cancer specialists for further evaluation.

Study Results

Thrive's blood test doubled the number of cancers first found through screening. Among the eligible participants, 96 women developed cancers: 26 of these were first identified by Thrive's blood test, 24 were first identified by standard-of-care screening methods, and 46 were first identified by symptoms or other means. Thrive's blood test detected cancers across ten different organs, including seven organs that do not have standard-of-care screening tools available. Notably, 65% of cancers detected by Thrive's blood test were identified as local or regional disease, allowing for earlier intervention and if indicated, surgery with intent to cure. Thrive's blood test's sensitivity was 27.1% across all cancers and 31.1% for the seven cancers with no screening options. Importantly, Thrive's blood test plus standard-of-care testing had a combined sensitivity of 52.1%, underscoring that a multi-cancer blood test is both a significant added benefit and complementary to standard-of-care screening tools.

Maintaining a high specificity thereby minimizing "false-positive" results is essential for a multi-cancer blood test. Screening with Thrive's blood test alone had a 98.9% specificity, and when combined with imaging had a specificity of 99.6%. Thrive's blood test plus imaging safely and efficiently guided clinical follow-up in blood test-positive participants with zero adverse events. Holistically, in this asymptomatic population with a cancer incidence of approximately 1%, Thrive's blood test plus imaging resulted in a positive predictive value (PPV) of 40.6%, which is considerably higher than the PPV of existing single-cancer screening tests available today.

"Through this first-ever interventional study, the teams at Johns Hopkins University, Geisinger and Thrive have forged a new path and advanced the field of blood-based earlier cancer detection," said David J. Daly, chief executive officer of Thrive. "Thrive is now one step closer to realizing our vision of providing a comprehensive approach to cancer screening, helping to shift the paradigm so that in the future, most cancers can be identified through earlier detection when there is the greatest opportunity for cure."

Credit: 
Thrive Earlier Detection Corp.

Understanding how fluids heat or cool surfaces

Whether it's water flowing across a condenser plate in an industrial plant, or air whooshing through heating and cooling ducts, the flow of fluid across flat surfaces is a phenomenon at the heart of many of the processes of modern life. Yet, aspects of this process have been poorly understood, and some have been taught incorrectly to generations of engineering students, a new analysis shows.

The study examined several decades of published research and analysis on fluid flows. It found that, while most undergraduate textbooks and classroom instruction in heat transfer describe such flow as having two different zones separated by an abrupt transition, in fact there are three distinct zones. A lengthy transitional zone is just as significant as the first and final zones, the researchers say.

The discrepancy has to do with the shift between two different ways that fluids can flow. When water or air starts to flow along a flat, solid sheet, a thin boundary layer forms. Within this layer, the part closest to the surface barely moves at all because of friction, the part just above that flows a little faster, and so on, until a point where it is moving at the full speed of the original flow. This steady, gradual increase in speed across a thin boundary layer is called laminar flow. But further downsteam, the flow changes, breaking up into the chaotic whirls and eddies known as turbulent flow.

The properties of this boundary layer determine how well the fluid can transfer heat, which is key to many cooling processes such as for high-performance computers, desalination plants, or power plant condensers.

Students have been taught to calculate the characteristics of such flows as if there was a sudden change from laminar flow to turbulent flow. But John Lienhard, the Abdul Lateef Jameel Professor of Water and of mechanical engineering at MIT, made a careful analysis of published experimental data and found that this picture ignores an important part of the process. The findings were just published in the Journal of Heat Transfer.

Lienhard's review of heat transfer data reveals a significant transition zone between the laminar and turbulent flows. This transition zone's resistance to heat flow varies gradually between those of the two other zones, and the zone is just as long and distinctive as the laminar flow zone that precedes it.

The findings could potentially have implications for everything from the design of heat exchangers for desalination or other industrial scale processes, to understanding the flow of air through jet engines, Lienhard says.

In fact, though, most engineers working on such systems understand the existence of a long transition zone, even if it's not in the undergraduate textbooks, Lienhard notes. Now, by clarifying and quantifying the transition, this study will help to bring theory and teaching into line with real-world engineering practice. "The notion of an abrupt transition has been ingrained in heat transfer textbooks and classrooms for the past 60 or 70 years," he says.

The basic formulas for understanding flow along a flat surface are the fundamental underpinnings for all of the more complex flow situations such as airflow over a curved airplane wing or turbine blade, or for cooling space vehicles as they reenter the atmosphere. "The flat surface is the starting point for understanding how any of those things work," Lienhard says.

The theory for flat surfaces was set out by the German researcher Ernst Pohlhausen in 1921. But even so, "lab experiments usually didn't match the boundary conditions assumed by the theory. A laboratory plate might have a rounded edge or a nonuniform temperature, so investigators in the 1940s, 50s, and 60s often 'adjusted' their data to force agreement with this theory," he says. Discrepancies between otherwise good data and this theory also led to heated disagreements among specialists in the heat transfer literature.

Lienhard found that researchers with the British Air Ministry had identified and partially solved the problem of nonuniform surface temperatures in 1931. "But they weren't able to fully solve the equation they derived," he says. "That had to wait until digital computers could be used, starting in 1949." Meanwhile, the arguments between specialists simmered on.

Lienhard says that he decided to take a look at the experimental basis for the equations that were being taught, realizing that researchers have known for decades that the transition played a significant role. "I wanted to plot data with these equations. That way, students could see how well the equations did or didn't work," he said. "I looked at the experimental literature all the way back to 1930. Collecting these data made something very clear: What we were teaching was terribly oversimplified." And the discrepancy in the description of fluid flow meant that calculations of heat transfer were sometimes off.

Now, with this new analysis, engineers and students will be able to calculate temperature and heat flow accurately across a very wide range of flow conditions and fluids, Lienhard says.

Credit: 
Massachusetts Institute of Technology

BU researchers: Race and income shape COVID-19 risk

Underlying conditions that increase risk of severe illness or death from COVID-19 are much more common among Black, Native American, and lower-income people in the United States.

The new coronavirus does not discriminate, but discrimination and inequality have shaped the risk of severe illness and death, according to a new Boston University School of Public Health (BUSPH) study.

The study, published in the American Journal of Preventive Medicine, finds that black, Native American, and lower-income people are much more likely to have one or more of the risk factors for severe or deadly COVID-19 illness identified by the Centers for Disease Control and Prevention (CDC), such as asthma, diabetes, or being pregnant or over 65 years old.

"In many respects, COVID-19 is the latest chapter in the book about how structural disparities shape the burden of disease in America," says study lead author Mr. Matthew Raifman, a doctoral student in environmental health at BUSPH.

"Decades of structural inequities in education, employment, housing, stress, and other factors have shaped disparities in the burden of chronic diseases by race, ethnicity, and income," says study co-author Dr. Julia Raifman, assistant professor of health law, policy & management at BUSPH (the two authors are married). "Now, these structural inequities have created a context in which people who are black, American Indian, or lower income face additional risk of death if they contract COVID-19," she says.

The researchers used 2018 data on over 330,000 people from the nationally-representative Behavioral Risk Factor Surveillance System, and looked at the prevalence of the COVID-19 risk factors. They estimated that 43 percent of American adults--approximately 97 million people--have at least one risk factor, and 18 percent--approximately 40 million people--have two or more.

Among those under 65 years old, 33 percent of black and 42 percent of Native American adults had at least one risk factor, compared to 27 percent of white adults. And 11 percent of black and 18 percent of Native American respondents had multiple risk factors, compared to 8 percent of white respondents.

For those 65 years old or older, 69 percent of Native American and 61 percent of black respondents had one or more additional risk factors beyond age, compared to 54 percent of white respondents.

The researchers found that at least 25 million people living in low-income households have at least one risk factor. Among those under 65 years old, low-income respondents were almost twice as likely to have one or more risk factors than high-income respondents, and more than twice as likely to have multiple risk factors. Low income respondents over 65 years old were also more likely to have multiple risk factors beyond age.

The authors note that the inequities that contribute to chronic conditions also make these populations more likely to work in jobs that cannot be done remotely, and to live in crowded, multi-generational homes, increasing their risk of exposure to the coronavirus.

"People who are black, American Indian, or lower income are both more likely to be exposed to COVID-19 and more likely to develop severe illness if they contract the virus," Mr. Raifman says.

"As society considers return-to-work policies and recovery efforts, it's important to recognize that risk of exposure and the severity of COVID-19 is not uniform across America," he says. "There's a real risk that the rising tide of recovery will not lift all boats equally--and, worse, that it might further exacerbate disparities in health for minorities and the least affluent among us."

Policies that reduce inequities can also help fight the coronavirus, and vice versa, Dr. Raifman says.

"Policies such as freezing evictions, rent, and mortgage payments for people affected by COVID-19 may help people stay in their homes, and expanding SNAP benefits may help people have enough to eat," she says. "As COVID-19 compounds existing health disparities, it highlights the importance of policies that support more equitable health over the long term."

Credit: 
Boston University School of Medicine

Ayurveda and yoga for COVID-19 prevention

image: Dedicated to research on paradigm, practice, and policy advancing integrative health.

Image: 
Mary Ann Liebert, Inc., publishers

New Rochelle, NY, April 28, 2020--Experts in Indian traditional medicine, including the chair of the Government of India's committee charged to lead that nation's efforts on the potential uses of traditional medicine relative to COVID-19, describe how the approach of Ayurveda and yoga may help strengthen host immunity and provide an effective, accessible, and affordable means of prophylaxis of COVID-19 infection. A well-referenced description of how Ayurveda can support local and systemic prophylaxis of COVID-19 is published in JACM, The Journal of Alternative and Complementary Medicine, a peer-reviewed publication from Mary Ann Liebert, Inc., publishers, dedicated to paradigm, practice, and policy advancing integrative health. Click here to read the full-text article free on the JACM website.

The paper, entitled "Public Health Approach of Ayurveda and Yoga for COVID-19 Prophylaxis" is co-authored by Girish Tillu, PhD and Bhushan Patwardhan, PhD, AYUSH Center of Excellence, Savitribai Phule Pune University, Sarika Chaturvedi, PhD, DrDY, Patil University, and Arvind Chopra, MD, Center for Rheumatic Diseases, Pune, India. During the article's production, Patwardhan, the article's anchor author, was named by the Indian Ministry of AYUSH (Ayurveda, Yoga, Unani, Siddha, Homeopathy and Naturopathy) as chair of the 18-member Interdisciplinary Ayush Research and Development Taskforce for initiating, coordinating and monitoring efforts against COVID-19.

Ayurveda focuses on the host response and includes herbal preparations as well as measures for a healthy lifestyle to better cope with various stressors, including infection. This concept of stimulating immune function is a cornerstone of Ayurvedic practice. The authors discuss local prophylaxis, including use of Ayurvedic practices to help block virus entry to the body and passage to the lungs. This may include consumption of hot water, hot food and herbal drinks, gargling with medicated water, and steam inhalation. Systemic prophylaxis focuses on overall health and includes factors such as diet, sleep, mental relaxation, lifestyle behaviors, and yoga. The authors describe the science supporting Rasayana therapies, a specialty of Ayurveda that deals with rejuvenation and can stimulate immunity. They note botanicals that have been found to be effective in immunomodulation and restoration of immune homeostasis.

JACM Editor-in-Chief John Weeks, johnweeks-integrator.com, Seattle, WA, states: "In COVID-19 we are seeing a collision of the acute (the virus) -- and the chronic (the host conditions that increase susceptibility). The authors assemble a well-referenced argument from biomedical research and some traditional texts to make a compelling case for more increased clinician and research attention to integrating Ayurveda and Yoga with biomedical approaches as prophylactic, host-supporting measures."

Credit: 
Mary Ann Liebert, Inc./Genetic Engineering News

Spinal cord gives bio-bots walking rhythm

image: Bio-bots are propelled by a ring of muscle on a hydrogel skeleton. Illinois researchers have been the first to innervate them with rat spinal cord segments, giving the 'spinobots' a natural walking rhythm.

Image: 
Image courtesy Collin Kaufman

CHAMPAIGN, Ill. -- Miniature biological robots are making greater strides than ever, thanks to the spinal cord directing their steps.

University of Illinois at Urbana-Champaign researchers developed the tiny walking "spinobots," powered by rat muscle and spinal cord tissue on a soft, 3D-printed hydrogel skeleton. While previous generations of biological robots, or bio-bots, could move forward by simple muscle contraction, the integration of the spinal cord gives them a more natural walking rhythm, said study leader Martha Gillette, a professor of cell and developmental biology.

"These are the beginnings of a direction toward interactive biological devices that could have applications for neurocomputing and for restorative medicine," Gillette said.

The researchers published their findings in the journal APL Bioengineering.

To make the spinobots, the researchers first printed the tiny skeleton: two posts for legs and a flexible "backbone," only a few millimeters across. Then, they seeded it with muscle cells, which grew into muscle tissue. Finally, they integrated a segment of lumbar spinal cord from a rat.

"We specifically selected the lumbar spinal cord because previous work has demonstrated that it houses the circuits that control left-right alternation for lower limbs during walking," said graduate student Collin Kaufman, the first author of the paper. "From an engineering perspective, neurons are necessary to drive ever more complex, coordinated muscle movements. The most challenging obstacle for innervation was that nobody had ever cultured an intact rodent spinal cord before."

The researchers had to devise a method not only to extract the intact spinal cord and then culture it, but also to integrate it onto the bio-bot and culture the muscle and nerve tissue together - and do it in a way that the neurons form junctions with the muscle.

The researchers saw spontaneous muscle contractions in the spinobots, signaling that the desired neuro-muscular junctions had formed and the two cell types were communicating. To verify that the spinal cord was functioning as it should to promote walking, the researchers added glutamate, a neurotransmitter that prompts nerves to signal muscle to contract.

The glutamate caused the muscle to contract and the legs to move in a natural walking rhythm. When the glutamate was rinsed away, the spinobots stopped walking.

Next, the researchers plan to further refine the spinobots' movement, making their gaits more natural. The researchers hope this small-scale spinal cord integration is a first step toward creating in vitro models of the peripheral nervous system, which is difficult to study in live patients or animal models.

"The development of an in vitro peripheral nervous system - spinal cord, outgrowths and innervated muscle - could allow researchers to study neurodegenerative diseases such as ALS in real time with greater ease of access to all the impacted components," Kaufman said. "There are also a variety of ways that this technology could be used as a surgical training tool, from acting as a practice dummy made of real biological tissue to actually helping perform the surgery itself. These applications are, for now, in the fairly distant future, but the inclusion of an intact spinal cord circuit is an important step forward."

Credit: 
University of Illinois at Urbana-Champaign, News Bureau

Harnessing psyllid peptides to fight citrus greening disease

image: Asian citrus psyllids feed on a citrus tree. The psyllids deposit a bacterium in the sap that causes citrus greening disease, a scourge to the citrus industries in Florida and California, worth a combined $17 billion.

Image: 
Image BTI

ITHACA, NY, April 17, 2020 -- Citrus greening disease, also called huanglongbing (HLB), is a bacterial infection of citrus trees that results in small, misshapen and sour fruits that are unsuitable for consumption, ultimately killing the tree. Because there is no cure, HLB is a major threat to the $10 billion citrus industry in Florida, where it was first detected in 2005, and to the $7 billion industry in California, where it appeared last year.

Researchers from the Boyce Thompson Institute, the U.S. Department of Agriculture Agricultural Research Service (USDA-ARS) and the University of Washington (UW), led by Michelle Heck, investigated a seemingly unlikely source of biocontrols for HLB: neuropeptides found in the insect that carries the disease-causing bacterium. Asian citrus psyllids (Diaphorina citri) infect citrus trees with Candidatus Liberibacter asiaticus (CLas) bacterium by feeding on their leaves and stems.

Laura Fleites, a USDA T.W. Edminster Research Associate in Heck's group at BTI, focused on neuropeptides because they function as hormones in hemipteran insects - a class that includes psyllids, aphids, whiteflies, shield bugs and other crop-plaguing species - to regulate growth, development and other biological functions. Moreover, other studies have shown that analogs of insect-derived neuropeptides kill pea aphids, and insecticides based on the kinin family of neuropeptides have been developed.

"If we could develop an insecticide that is specific for Asian citrus psyllids based on one of the insect's own neuropeptides, then we could protect citrus trees from the insect that spreads CLas," Heck said. "Citrus greening disease is devastating our citrus industry, and we need to develop new ways for our citrus growers to control it."

As reported in the April 3 issue of Journal of Proteome Research, Fleites and the team characterized the full array of peptides found in the psyllids and identified 122 candidate neuropeptides. While promising, the findings offer only potential starting points for combatting HLB, because unmodified insect-derived neuropeptides lack the stability, bioavailability and half-lives needed for use as insecticides in the citrus grove.

To turn the findings into a usable product, the team is now collaborating with Ronald Nachman, a USDA researcher at College Station, Texas, Robert Shatters, a USDA researcher in Fort Pierce Florida, and Mark Trimmer from AgroSource, Inc, a small agritech company, to identify the best psyllid-derived neuropeptide for development. Then, the team will stabilize the peptide and decide the optimum method for delivering the insecticidal molecule to citrus trees - whether as a spray, by engineering trees to make the peptides themselves, or some other method.

For the study, Fleites, developed new extraction and analysis methods that other researchers could use in their investigations of insect peptides.

"Thanks to USDA support, I was able to develop techniques that enable the identification of small, functional insect peptides separately from their larger, inactive precursors," said Fleites. "Because these techniques aren't specific to psyllids, they may be useful for identifying neuropeptides in other hemipteran insects to protect crop plants."

Heck noted that this work shows how USDA grant programs can be used to fund everything from discovery to product development. "We performed the neuropeptide discovery in a study funded by NIFA, and are now doing the translational work under a different USDA grant program from APHIS," she said.

Credit: 
Boyce Thompson Institute

Hubble captures breakup of comet ATLAS

image: The NASA/ESA Hubble Space Telescope has provided astronomers with the sharpest view yet of the breakup of Comet C/2019 Y4 (ATLAS). The telescope resolved roughly 30 fragments of the comet on 20 April and 25 pieces on 23 April.

Image: 
NASA, ESA, D. Jewitt (UCLA), Q. Ye (University of Maryland)

The NASA/ESA Hubble Space Telescope has provided astronomers with the sharpest view yet of the breakup of Comet C/2019 Y4 (ATLAS). The telescope resolved roughly 30 fragments of the fragile comet on 20 April and 25 pieces on 23 April.

The comet was first discovered in December 2019 by the ATLAS (Asteroid Terrestrial-impact Last Alert System) robotic astronomical survey system in Hawai?i, USA. It brightened quickly until mid-March, and some astronomers initially anticipated that it might be visible to the naked eye in May to become one of the most spectacular comets seen in the last two decades. However, the comet abruptly began to get dimmer, leading astronomers to speculate that the icy core may be fragmenting, or even disintegrating. ATLAS's fragmentation was confirmed by amateur astronomer Jose de Queiroz, who photographed around three pieces of the comet on 11 April.

The Hubble Space Telescope's new observations of the comet's breakup on 20 and 23 April reveal that the broken fragments are all enveloped in a sunlight-swept tail of cometary dust. These images provide further evidence that comet fragmentation is probably common and might even be the dominant mechanism by which the solid, icy nuclei of comets die.

"Their appearance changes substantially between the two days, so much so that it's quite difficult to connect the dots," said David Jewitt of UCLA, leader of one of two teams who imaged the doomed comet with Hubble. "I don't know whether this is because the individual pieces are flashing on and off as they reflect sunlight, acting like twinkling lights on a Christmas tree, or because different fragments appear on different days."

"This is really exciting -- both because such events are super cool to watch and because they do not happen very often. Most comets that fragment are too dim to see. Events at such scale only happen once or twice a decade," said the leader of the second Hubble observing team, Quanzhi Ye, of the University of Maryland.

Because comet fragmentation happens quickly and unpredictably, reliable observations are rare. Therefore, astronomers remain largely uncertain about the cause of fragmentation. One suggestion is that the original nucleus spins itself into pieces because of the jet action of outgassing from sublimating ices. As this venting is likely not evenly dispersed across the comet, it enhances the breakup. "Further analysis of the Hubble data might be able to show whether or not this mechanism is responsible," said Jewitt. "Regardless, it's quite special to get a look with Hubble at this dying comet."

Hubble's crisp images may yield new clues to the breakup. The telescope has distinguished pieces as small as the size of a house. Before the breakup, the entire nucleus may have been no more than the length of two football fields.

The disintegrating ATLAS comet is currently located inside the orbit of Mars, at a distance of approximately 145 million kilometres from Earth when the latest Hubble observations were taken. The comet will make its closest approach to Earth on 23 May at a distance of approximately 115 million kilometres, and eight days later it will skirt within 37 million kilometres of the Sun.

Credit: 
ESA/Hubble Information Centre

New study finds biases against physically dirty people take root as early as age 5

image: Researchers from Boston College and Franklin & Marshall College used "twin" images of clean and dirty people to test respondents attitudes toward physically unclean people. They found people develop biases against individuals who are physically dirty as early as the age of five and carry these perceptions into adulthood.

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Journal of Experimental Child Psychology

Chestnut Hill, Mass. (4/28/2020) - The biases individuals harbor against people they see as physically dirty emerge in children as young as five years old and persist into adulthood, according to a new study by researchers from Boston College and Franklin & Marshall College, who found these prejudices extend to the sick and may hold implications for people diagnosed with Covid-19.

In three experiments involving approximately 260 respondents, the researchers found children's and adults' biases were stronger when evaluating similarly aged peers and crossed cultural boundaries when tested in the U.S. and India, according to the report, published in an advance online edition of the Journal of Experimental Child Psychology.

The findings carry social implications for the current COVID-19 crisis, as they suggest that people might adopt negative beliefs and attitudes toward those who contract the novel coronavirus, said Boston College Associate Professor of Psychology Angie Johnston, a co-author of the report "In sickness and in filth: Developing a disdain for dirty people."

"With the exponential increase in the number of confirmed cases of COVID-19, people are increasingly likely to know somebody with the virus," said Johnston. "It will be critically important for both children and adults to know to stay away from individuals who are contagious. However, it is possible that the stigma directed toward those who test positive for the coronavirus will last well beyond the course of the illness, and that other, less warranted avoidance tendencies will form and persist."

Avoiding filth and germs is typically advantageous. However, when other people are physically dirty or sick, often through no fault of their own - such as being homeless, or working a "dirty job" - the tendencies toward avoidance can lead to problematic social biases, said Joshua Rottman, an Assistant Professor at Franklin & Marshall and co-author on the report.

In their research, Johnston and Rottman found that children and adults from both the United States and India are less likely to trust information conveyed by people who are unclean, and they are also less likely to attribute positive traits - such as intelligence or kindness - to individuals they see as unclean or unhygienic.

The researchers used three experiments to measure bias in children, between the ages of five and nine, and adults against individuals who are sick or physically unclean, and determine whether these biases extend across cultures. Respondents were shown photos of identical twins, one dressed neatly in a clean setting; the other in stained, disheveled clothing in a setting littered with trash.

The team's first study found that children and adults consider clean adults to be more likely to possess favorable traits than dirty adults, and adults have particularly strong tendencies to trust information provided by clean adults.

The second study showed that only children view clean children as possessing more favorable traits than dirty children, but both children and adults selectively trust the testimony of clean children.

A third study in India uncovered similar patterns of results.

"Taken as a whole, these findings suggest that people who are perceived to be dirty will be frequently mistrusted, marginalized, maligned, and misunderstood from an early age," the researchers conclude.

"These biases are generally constant across different causes of dirtiness," said Rottman. "There are not clear differences between biases directed toward individuals who are sick versus individuals who are intentionally dirty versus individuals who are accidentally dirty."

In addition to the social implications for the current COVID-19 crisis, the findings may pertain to certain segments of society labeled as "dirty." The team is currently investigating whether dirtiness stereotypes - such as labeling immigrants as "dirty" - elicit similar social biases in children.

Credit: 
Boston College

Study reveals important flowering plants for city-dwelling honey bees

image: The researchers found that trees, like maples, oaks and willows, were the most important spring pollen sources for honey bees.

Image: 
Douglas Sponsler, Penn State

UNIVERSITY PARK, Pa. -- Trees, shrubs and woody vines are among the top food sources for honey bees in urban environments, according to an international team of researchers. By using honey bees housed in rooftop apiaries in Philadelphia, the researchers identified the plant species from which the honey bees collected most of their food, and tracked how these food resources changed from spring to fall. The findings may be useful to homeowners, beekeepers and urban land managers who wish to sustain honey bees and other bee and pollinator species.

"We know that cities can support a surprising diversity of bee species; however, cities are complex environments, and traditional floral surveying methods can be hard to implement," said Christina Grozinger, Distinguished Professor of Entomology and director of the Center for Pollinator Research, Penn State. "By analyzing the pollen that honey bees brought back to their colonies and how the weights of these colonies changed every hour, we were able to identify the flowering plants that provide the most nutrition for bees in Philadelphia, and understand how these resources change across the seasons."

The researchers installed 12 apiaries, each containing three honey bee colonies, at locations throughout Philadelphia. Each colony was equipped with a pollen trap for capturing incoming pollen and a scale for logging its weight once per hour. The team visited each apiary monthly to collect pollen samples. They sequenced the DNA from the samples to determine which plant genera were present in each sample. Their findings appeared on April 27 in the journal Ecosphere.

"Ours is the first study to combine two novel techniques -- continuous colony weight monitoring and pollen DNA metabarcoding -- to answer simultaneously the questions of 'what' and 'how much' with respect to the flowers that are available to foraging insects," said Douglas Sponsler, postdoctoral scholar in entomology, Penn State. "Colony weight patterns tell us when resources are plentiful and when they are scarce. Pollen DNA metabarcoding tells us which plants are available at a given time and how the floral community changes through the year."

The team found that the availability of floral resources in Philadelphia follows a consistent seasonal pattern -- floral resources are plentiful in spring, scarce in summer, and briefly plentiful again in late summer and early fall before becoming scarce for the remainder of the year.

Specifically, trees like maples, oaks and willows were the most important spring pollen sources. During the summer when resources were scarce, crepe myrtle, Japanese pagoda tree and devil's walking stick emerged as important species. In summer and fall, woody vines, such as Virginia creeper, English ivy and autumn clematis, dominated the pollen samples.

"Vines are not traditionally regarded as major foraging resources for pollinators, and what we discovered in our study system may be a novelty of urban ecosystems," said Sponsler. "Vines such as the ones we found thrive on the vertical surfaces of built environments, and many of them have been introduced by humans as garden plants."

According to the researchers, the study highlights at least three actionable findings.

Bees need flowering trees, so urban forestry should be a top priority in urban land management.

Many of the plants that were important in the study are associated with once-disturbed habitats that now harbor rich floral resources, so weedy areas should be valued.

While native plant species are usually the best for supporting bees and other pollinators, ornamental plant species can provide important nutritional resources as well, particularly in periods when other plants are not blooming.

"Care should be taken to avoid plants with a strong potential to become invasive," said Sponsler. "But as far as ornamentals go, summer-blooming species like Japanese pagoda tree and crepe myrtle might alleviate seasonal shortages of floral resources. In the eastern U.S., native species like eastern redbud, American linden and some varieties of hydrangea are good options for ornamental plantings."

Groziner noted that although caution should be taken in extrapolating the findings to cities beyond Philadelphia, the overall consistency of the team's findings with comparable datasets suggests that the patterns seen in the data are likely the same as would be found in similar locations. Grozinger noted that several other studies from their group have found that ornamental plants can provide good nutrition for bees, and often provide season-long blooms. More information on creating gardens for pollinators can be found on the Penn State Master Gardeners Pollinator Garden Certification Program site.

"Our data can inform urban land management, such as the design of ecologically functional ornamental plantings, while also providing practical guidance to beekeepers seeking to adapt their management activities to floral resource seasonality," Grozinger said.

Credit: 
Penn State

Hubble watches comet ATLAS disintegrate into more than 2 dozen pieces

image: These two Hubble Space Telescope images of comet C/2019 Y4 (ATLAS), taken on April 20 (left) and April 23, 2020, provide the sharpest views yet of the breakup of the solid nucleus of the comet. Hubble's eagle-eye view identifies as many as 30 separate fragments. Hubble distinguishes pieces that are roughly the size of a house. Before the breakup, the entire nucleus of the comet may have been the length of one or two football fields. Astronomers aren't sure why this comet broke apart. The comet was approximately 91 million miles (146 million kilometers) from Earth when the images were taken.

Image: 
NASA, ESA, STScI and D. Jewitt (UCLA)

These two Hubble Space Telescope images of comet C/2019 Y4 (ATLAS), taken on April 20 and 23, 2020, provide the sharpest views yet of the breakup of the fragile comet.

Hubble identified about 30 fragments on April 20, and 25 pieces on April 23. They are all enveloped in a sunlight-swept tail of cometary dust. "Their appearance changes substantially between the two days, so much so that it's quite difficult to connect the dots," said David Jewitt, professor of planetary science and astronomy at UCLA, Los Angeles, and leader of one of two teams that photographed the doomed comet with Hubble. "I don't know whether this is because the individual pieces are flashing on and off as they reflect sunlight, acting like twinkling lights on a Christmas tree, or because different fragments appear on different days."

"This is really exciting -- both because such events are super cool to watch and because they do not happen very often. Most comets that fragment are too dim to see. Events at such scale only happen once or twice a decade," said the leader of a second Hubble observing team, Quanzhi Ye, of the University of Maryland, College Park.

The results are evidence that comet fragmentation is actually fairly common, say researchers. It might even be the dominant mechanism by which the solid, icy nuclei of comets die. Because this happens quickly and unpredictably, astronomers remain largely uncertain about the cause of fragmentation. Hubble's crisp images may yield new clues to the breakup. Hubble distinguishes pieces as small as the size of a house. Before the breakup, the entire nucleus may have been no more than the length of two football fields.

One idea is that the original nucleus spun itself into pieces because of the jet action of outgassing from sublimating ices. Because such venting is probably not evenly dispersed across the comet, it enhances the breakup. "Further analysis of the Hubble data might be able to show whether or not this mechanism is responsible," said Jewitt. "Regardless, it's quite special to get a look with Hubble at this dying comet."

The comet was discovered on Dec. 29, 2019, by the ATLAS (Asteroid Terrestrial-impact Last Alert System) robotic astronomical survey system based in Hawaii. This NASA-supported survey project for Planetary Defense operates two autonomous telescopes that look for Earth-approaching comets and asteroids.

The comet brightened quickly until mid-March, and some astronomers anticipated that it might be visible to the naked eye in May to become one of the most spectacular comets seen in the last 20 years.

However, the comet abruptly started to get dimmer instead of brighter. Astronomers speculated that the icy core may be fragmenting, or even disintegrating. ATLAS' fragmentation was confirmed by amateur astronomer Jose de Queiroz, who was able to photograph around three pieces of the comet on April 11.

The disintegrating comet was approximately 91 million miles (146 million kilometers) from Earth when the latest Hubble observations were taken. If any of it survives, the comet will make its closest approach to Earth on May 23 at a distance of about 72 million miles (116 million kilometers), and eight days later it will skirt past the Sun at 25 million miles (40 million kilometers).

Credit: 
NASA/Goddard Space Flight Center

The Lancet Infectious Diseases: Contact tracing and isolation key to controlling SARS-CoV2 in Shenzhen

Contact tracing to rapidly isolate people who could be infected with coronavirus disease 2019 (COVID-19) reduced the length of time people were infectious in the community over 4 weeks (from 14 January to 12 February 2020) in Shenzhen, China, according to results from 391 cases and 1,286 of their close contacts, published in The Lancet Infectious Diseases journal.

In Shenzhen, authorities identified who to isolate based on their contact with confirmed cases, as well as isolating people who already had symptoms. The new study finds that contact tracing increased the speed at which new cases were confirmed by 2 days (an average of 5.5 days initially, reduced to 3.2 with contact tracing). It also reduced the amount of time it took to isolate infected people by 2 days (from an average of 4.6 days down to 2.7). There were only three deaths in the study group during the study period.

On January 8, 2020, authorities began to monitor travellers from Hubei province for symptoms such as a fever and cough, and after 2 weeks expanded to monitor people without symptoms as well as the wider community. Suspected cases and their close contacts provided nasal swabs, which were tested for coronavirus at 28 local hospital and 12 other centres. People with symptoms were isolated and treated in hospital before their test results were known, and those without symptoms were quarantined at dedicated facilities. Close contacts who tested negative were quarantined at home or in a dedicated facility and monitored for 14 days.

During the study period, the reproductive number among observed cases was 0.4, far below the threshold of 1 required for incidence to decline. However, since this was only among traced contacts the true reproductive number was likely higher, though the end of the local outbreak suggests it also was below 1.

"The experience of COVID-19 in the city of Shenzhen may demonstrate the huge scale of testing and contact tracing that's needed to reduce the virus spreading," says Dr Ting Ma from the Harbin Institute of Technology at Shenzhen, China. "Some of the strict control measures enforced here, such as isolating people outside their homes, might be unlikely to be replicated elsewhere, but we urge governments to consider our findings in the global response to COVID-19. To achieve similar results, other countries might be able to combine near-universal testing and intensive contact tracing with social distancing and partial lockdowns. Although no lockdown measures were introduced in Shenzhen until the end of our study period, Wuhan's lockdown could have significantly restricted the spread of coronavirus to Shenzhen." [2]

For the current study, the authors analysed data from 391 people diagnosed with COVID-19 after they showed symptoms, and 1,286 of their close contacts. The contacts were tested irrespective of whether they had symptoms in order to identify infected people who were asymptomatic. The data gave insights into the type of contact most likely to lead to transmission. Close contacts were defined as people who shared a household with infected patients up to 2 days before they started showing symptoms, or interacted with them socially by travelling or eating together.

For people who were isolated because they showed symptoms of COVID-19, it took an average of 4.6 days for them to be isolated following the first signs of infection. Contact tracing reduced this to an average of 2.7 days. For people diagnosed with COVID-19 after being contact traced and tested (87 people), a fifth (17 out of 87 people) had not yet developed any symptoms, and 30% (25 out of 87) did not have a fever.

Contact tracing also reduced the length of time between someone first experiencing symptoms and being diagnosed. It took an average of 5.5 days if people were only tested after they reported symptoms, but with contact tracing there was only a delay of an average of 3.2 days between the first symptoms and a confirmed diagnosis.

The length of time for which a person remains infectious is not yet known, but reducing the amount of time that infected people interacted with others appears to have helped reduce the virus spreading.

In this study, transmission was most likely between people who shared a household, but not all close contacts caught COVID-19, with only 11% of close contacts of this kind developing the disease. Of close contacts who travelled together with an infected person (for example on a plane, bus, train or boat), an average of 6% developed the disease. Of close contacts who shared a meal with an infected person, an average of 9% developed the disease. The authors note that these transmission rates will be higher in other countries, where measures such as isolation outside the home might not be as strict or rapid. These data do not give any insights into why some cases cause higher levels of transmission than others.

The study also provided results on the likelihood of infection by age group, the severity of symptoms according to age group, the incubation period before symptoms began, and the recovery time or time to death. The results were consistent with those from previous studies.

The authors highlight several limitations to their study, including that it is impossible to trace every potential contact an individual has. Contact tracing therefore focuses on close contacts who are most likely to be infected. They note that some infected travellers to Shenzhen could have been missed if they were only tested due to symptoms such as a fever. Their contacts might also have been missed if they were asymptomatic, because the PCR test is not sensitive enough to pick up every case.

Writing in a linked Comment, lead epidemiologist Dr Cécile Viboud (who was not involved in the study) from the National Institutes of Health, USA, says: "As we look towards post-lockdown strategies, we should examine the experience of countries that have successfully controlled SARS-CoV-2 transmission or have low mortality (eg, China, Singapore, Taiwan, South Korea, Germany, and Iceland). Successful strategies include ample testing and contact tracing, supplemented by moderate forms of social distancing. Contact tracing on the scale that is needed for the SARS-CoV-2 response is labour intensive, and imperfect if done manually. Hence new technology-based approaches are greatly needed to assist in identification of contacts, especially if case detection is aggressive. Building on the SARS-CoV-2 experience in Shenzhen and other settings, we contend that enhanced case finding and contact tracing should be part of the long-term response to this pandemic--this can get us most of the way towards control."

Credit: 
The Lancet

Skoltech research shows how a 'Swiss Army knife' protein helps phages disarm their victims

image: Ocr, a DNA mimic protein of the well-studied T7 phage, can protect the virus from BREX (for BacteRiophage EX?lusion), a poorly studied set of bacterial defense mechanisms utilized by, among others, Escherichia coli, which T7 commonly infects

Image: 
Pavel Odinev / Skoltech

Researchers from the Severinov Laboratory at Skoltech, along with their colleagues from Switzerland and Israel, have investigated a poorly studied bacterial BREX defense mechanism to show that it can be "turned off" by a multipurpose viral protein that successfully impersonates DNA. The paper was published in the journal Nucleic Acids Research.

In the never-ending war between bacteria and viruses that infect them, it is extremely important to know where your DNA is. To protect themselves from hostile invasion, bacteria have learned to "mark" their own genetic material by methylating it at specific sites in the genome. All "unmarked" DNA, such as that of a bacteriophage, is then recognized, cleaved and degraded by an army of endonucleases. These are called restriction modification (RM) systems. The phages, in turn, have learned to evade these RM systems by using DNA mimic proteins. A protein that chemically "looks" like DNA to the bacterial restriction complex can bind it and prevent from ever getting to actual phage DNA.

Skoltech PhD student Artem Isaev and his colleagues from Tel Aviv University and Philip Morris International R&D have shown that Ocr, a DNA mimic protein of the well-studied T7 phage, is in fact a multipurpose tool. Besides inhibition of RM type I systems, it can also protect the phage from BREX (for BacteRiophage EX?lusion), another set of bacterial defense mechanisms utilized by, among others, Escherichia coli, which T7 commonly infects.

"Five years ago, we knew about restriction modification, CRISPR and Toxin-Antitoxin abortive infection systems, but recently bioinformatics has shown us that it is just a small proportion of the real diversity of defensive strategies employed by bacteria to cope with phage infections. BREX was the first in a row of novel phage defense systems: they are found in around 1 in 10 of all microorganisms, and in bacteria they are even more widespread than CRISPR. Yet we still don't know the function of five out of six BREX genes and how they are working together to provide protection," Isaev says.

It is yet unknown whether BREX simply destroys the incoming phage DNA or somehow inhibits its replication, but almost all BREX mechanisms employ a BrxX methyltransferase, an enzyme in charge of "marking" bacterial DNA for self-recognition. The Ocr protein apparently binds to this methyltransferase and thus prevents the BREX system from both methylation of the host DNA and attacking the non-methylated phage genome.

"We have shown that Ocr interacts with methyltransferase and inhibits host DNA methylation. In theory, this can lead to an autoimmune response: as host DNA is no longer "marked" as such, BREX exclusion complexes should attack it. Yet, we do not see self-toxicity after expression of Ocr, which indicates that Ocr inhibits these exclusion complexes as well, and thus BREX methyltransferase should be involved at the active stage of defense. Ocr is already known as an inhibitor of type I RM systems, and these systems also require methytransferase for restriction complexes. There are other similarities between BREX and RM systems, and we hope that they would help us understand how BREX functions," Isaev explains.

Other DNA mimic proteins do not seem to overcome the BREX defense, so researchers intend to further investigate how exactly Ocr does its job. As bacterial defense systems mostly deal with DNA recognition and manipulation, they can become powerful tools for molecular biology and medicine. Molecular cloning is possible thanks to the discovery and description of RM systems, and CRISPR has brought about the age of genome editing. Moreover, studying the arsenals of bacteria and phages may prove useful in "recruiting" the viruses as novel antimicrobial agents in the fight against antibiotic-resistant bacteria.

"Bacteria have been combatting phages for more than a billion years, and this constant "arms race" is one of the major evolutionary forces in the microworld. Both sides have developed an enormous arsenal of strategies to fight each other, and a great diversity of molecular machines has been invented in the process. For me personally, it's just fascinating to study what else is hidden in the genome and what novel mechanism we can discover in the process," Isaev concludes.

Credit: 
Skolkovo Institute of Science and Technology (Skoltech)

Making sense of the viral multiverse

image: Arvind Varsani is a molecular virologist in the Biodesign Center for Fundamental and Applied Microbiomics and a researcher in ASU's School of Life Sciences

Image: 
The Biodesign Institute at Arizona State University

In November of 2019--likely, even earlier--a tiny entity measuring just a few hundred billionths of a meter in diameter began to tear apart human society on a global scale. Within a few months, the relentless voyager known as SARS-CoV-2 had made its way to every populated corner of the earth, leaving scientists and health authorities with too many questions and few answers.

Today, researchers are scrambling to understand where and how the novel coronavirus arose, what features account for the puzzling constellation of symptoms it can cause and how the wildfire of transmission may be brought under control. An important part of this quest will involve efforts to properly classify this emergent human pathogen and to understand how it relates to other viruses we may know more about.

In a consensus statement, Arvind Varsani, a molecular virologist with ASU's Biodesign Center for Fundamental and Applied Microbiomics and a host of international collaborators propose a new classification system, capable of situating coronaviruses like SARS-CoV-2 within the enormous web of viruses across the planet, known as the virosphere.

In order to adequately categorize this astonishing viral diversity, the group proposes a 15-rank classification scheme and describe how three human pathogens--severe acute respiratory syndrome coronavirus (SARS CoV), Ebola virus, and herpes simplex virus 1, fit into the new framework.

Varsani is joined by other elected executive members of the International Committee on Taxonomy of Viruses (ICTV), an all-volunteer organization of leading virologists from around the world, dedicated to designing a workable nomenclature for defining viral species. Within the ICTV, approximately 100 distinct working groups composed of specialists within all major viral families labor to bring order to the tangled skein of elements in the virosphere.

The consensus statement appears in the advanced online edition of the journal Nature Microbiology.

A cupboard of viruses

The new ranking scheme, an elaboration of the earlier binomial classification system conceived by the great 18th century taxonomist Carl Linnaeus, seeks to incorporate the full range of genetic divergence in the virosphere.

As a test case, the consensus statement shows how three human pathogens can be neatly incorporated into the new system. At the level of realm, the lowest and most inclusive in the new taxonomy, two RNA viruses, Ebola virus (EBOV) and severe acute respiratory syndrome coronavirus (SARS-CoV) are grouped as 'riboviria', while herpes simplex 1, a double-stranded DNA virus, does not belong to the realm riboviria but is classified by five traditional ranks.

Devising an inclusive viral taxonomy is of great practical importance. It can play a vital role in detecting and identifying the agents responsible for emergent epidemics in humans, livestock or plants. Establishing a virus' taxonomic status allows for clear and unambiguous communication among virologists and the broader scientific community.

"With viral metagenomic studies (which involve sequencing genetic material directly recovered from the environment), we are discovering large amounts of viruses that we can not really put into any particular order," Varsani says. "We were tasked with trying to come up with a better taxonomic framework." The new scheme relies in part on the conservation of key viral proteins and other properties found among taxonomically-related viruses for higher ranks.

The virus causing the current outbreak of coronavirus disease, for example, has recently been named "severe acute respiratory syndrome coronavirus 2" (SARS-CoV-2), after the ICTV Coronaviridae Study Group determined the virus belongs to the existing species, "severe acute respiratory syndrome-related coronavirus," based in part on conserved proteins involved in SARS-CoV-2 viral replication. (Earlier classifications of coronaviruses were largely based on studies of serological reactivity with viral spike proteins, which give coronaviruses their characteristic mace-like appearance.)

Visualizing the virosphere

Even for scientists used to dealing in mind-bendingly extreme numbers, the virosphere is almost unfathomably vast. It has been estimated that 100 viruses could be assigned to every star in the entire universe without exhausting the world's supply, estimated at 1 nonillion (or 1 followed by 30 zeros).

"One important thing about all these frameworks for viral taxonomy is that they're dynamic. As we discover more viruses, things will have to shift," Varsani says. "And the same thing has happened in the floral kingdom, where people once classified plants based on petals, leaves and other morphological features. And soon, as genetic information has come in, it has contradicted the prior classification that people had. These issues are common across plant, animal, fungal and bacterial classification and will certainly take a lot of convincing to the initial proposers of that taxonomy. Perhaps a crude example is the wrongful classification of a plant as a daisy in the Asteraceae family, but in fact it is a plant that is mimicking a daisy, because it wants a particular pollinator and is genetically not part of Asteraceae."

But the extent and genetic diversity of the virome are just the beginning of the challenges facing researchers trying to develop a comprehensive taxonomy--a mega taxonomy--of the viral world. Viral lineages, for example, are exceptionally tricky to tease out. Unlike all cellular life on earth, viruses acquire their genomic material from many sources, a property known as polyphylogeny. Phenomena including horizontal transfer of genetic elements allow viruses to freely swap elements of their identity, leaving researchers without a clear line of descent.

Further, viral mutation rates are much faster and more prolific than their cellular counterparts, owing to poor mechanisms of genomic proofreading and error correction, as well as selective pressures pushing their relentless diversification.

Unity and diversity

Compared with other organisms, diversity among viruses is extreme. They may differ in their genetic material (RNA or DNA) and basic structure, (double or single stranded), as well as the orientation of their encoded genes. A further complication involves the fact that viral genomes may be distributed across distinct units, sometimes packaged together in a virion, or in separate virus particles, all of which are needed to infect a cell for replication to occur.

While all eukaryotes share a last common ancestor, distinct from those of bacteria and archaea, allowing researchers to track their evolutionary origins and divergences many billions of years into the past, viruses lack a set of universally conserved genes needed to construct a proper phylogeny.

The new 15-rank taxonomy elaborates on the Linnaean 7-tiered system of kingdom, phylum, class, order, family, genus, species. It also borrows physiological elements of the so-called Baltimore taxonomy, (developed by Nobel Laureate David Baltimore). The Baltimore system also recognizes 7 levels but is non-hierarchical and uses variables including genome type and replication-expression strategies to guide viral classification.

The new taxonomy is a significant step forward in the quest to bring global organization to the viral world. Further, despite the extreme diversity of evolutionary histories present in polyphyletic viruses, a unity pointing to a primordial pool of virus-like genetic elements is beginning to emerge. The entire subsequent history of life on earth may be read as a ceaseless dynamic between these selfish agents and their cellular hosts.

Credit: 
Arizona State University

Perception of US democracy tanks after Trump impeachment

image: Ratings of the health of US democracy by experts and the public on a 0-100 scale. The figure shows average values across survey waves.

Image: 
Bright Line Watch and University of Rochester graphic / Mike Osadciw

While President Donald Trump's impeachment gripped the country in late 2019 and early 2020, the long-term consequences of his trial and acquittal for American democracy remain yet unclear. What's clear already, however, is that both the public's and political experts' perceptions of the health of US democracy clearly declined during this period.

Those are the findings of an academic watchdog group that conducted its latest survey between March 12 and April 15.

Since February 2017, Bright Line Watch, a nonpartisan group of political scientists, has been surveying the American public as well as colleagues in academia in an effort to gauge the relative well-being of the nation's democracy. The group, which includes University of Rochester political science professor Gretchen Helmke, has been monitoring US democratic practices and potential threats.

The Bright Line Watch surveys consist of a two-part list of more than 25 statements of democratic principles that contribute to the overall stability and performance of American democracy. The first part asks citizens and experts to rate these democratic principles on how vital they are for democracy. The second part asks both citizens and experts how the US is performing on each of these principles.

Among the experts, the latest survey recorded 63.4 on a 0-100 scale of US democratic performance-- the worst overall rating since Bright Line Watch started asking these questions in 2017.

During the last year, the experts' ratings dropped on 15 of the 27 surveyed democratic principles, while none showed improvement. The biggest declines in performance relate to accountability, institutional checks and balances, and the rights and protections of individuals.

Ratings among the public show a similar decline, dropping from 54.3 in March 2019 to 49.3 a year later. Both expert and public evaluations mark substantial declines from a peak after the 2018 elections, which the team attributes to "an apparent increase in legal and political checks on President Trump following the 2018 midterm election, including investigations into the administration and the President's associates by law enforcement officials and Congress."

Meanwhile, the recent declines continue the trend already observed in the group's October 2019 survey. That drop came after the whistleblower report on Trump's Ukraine phone call.

Worth noting is that the decrease in public ratings is driven by Americans who disapprove of the president. For this group, assessments of democracy declined between March and October 2019 and remained low in the most recent survey. By contrast, ratings were stable among Trump approvers, the team writes in its latest survey.

Key findings of Bright Line Watch's March/April 2020 survey

The survey found that experts:

rated American democracy as performing sharply worse in March 2020 than in March 2019, the group's last survey before the impeachment process began

gave a lower rating to performance on democratic principles mainly related to impeachment

compared to a year ago, were more skeptical that investigations of public officials were free of political interference

do not regard the impeachment as having constrained President Trump. On the contrary, they identify many actions he and his allies took during the impeachment process as abnormal, and indicate that the process as a whole will embolden Trump substantially, an effect that may also extend to future presidents.

The survey of the general public showed that:

Americans remain divided in their evaluation of the performance of US democracy

the views of those who approve of President Trump have remained stable over the past year

those who disapprove of the president perceive a decline in democratic performance

the gap between the two groups is widest on principles of citizen equality and on checks on executive authority.

"We cannot establish any firm causal connections between real-world events and expert responses," says Helmke. "But the fact that the biggest declines correspond to measures related to accountability and checks and balances means our latest results are certainly consistent with the concern that the impeachment and acquittal of President Trump has had negative consequences for the experts' perceptions of the health of American democracy."

The scientists found strong consensus among the expert sample that the results of the impeachment and subsequent acquittal would embolden President Trump (79 percent) and that the effect would similarly embolden future presidents (59 percent).

"In our system, checks and balances function mainly as deterrents," Helmke says. "If politicians no longer believe that they will be sanctioned for pushing--let alone breaking--the law, then future transgressions become that much more likely."

However, the Bright Line Watch team cautions that the survey was conducted under the long shadow of the novel coronavirus. While the results are largely consistent with past surveys, it is too early to tell how the pandemic might have influenced survey responses.

Credit: 
University of Rochester

Disruptions in health insurance coverage are common and affect cancer care and survival

A new study finds disruptions in health insurance coverage are common in the United States and are associated with poorer cancer care and survival. The study appears in JNCI: The Journal of the National Cancer institute.

For years, experts have known that lack of health insurance coverage is associated with poor access and receipt of cancer care and survival in the United States. Meanwhile, disruptions in coverage are common among low-income populations and little is known how these disruptions can affect cancer care, from prevention and screening to diagnosis, treatment and survival.

Disruptions can be caused by gaps in coverage, or transitions between types of coverage (e.g., public and private) or between specific health insurance plans.

To learn more, investigators led by Robin Yabroff of the American Cancer Society conducted a systematic review of studies of health insurance coverage disruptions and cancer care and outcomes published between 1980 and 2019. They identified 29 observational studies for analysis.

In those studies, from 4.3% to 32.8% of adults experienced coverage disruptions. Those with coverage disruptions were less likely to receive cancer prevention or screening, and if diagnosed with cancer, they were more likely to have advanced disease, were less likely to receive treatment, and have worse survival than their counterparts without coverage disruptions.

"Our findings were consistent across multiple cancer sites, with several studies finding a 'dose-response' relationship, meaning the longer the disruption, the worse the care," said Robin Yabroff, PhD, lead author of the study. "The consistency of these findings across the cancer control continuum in our review highlights how important it is to minimize breaks in health insurance coverage to address cancer disparities and promote health equity."

Credit: 
American Cancer Society