It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Monday, June 29, 2020
Red Sea's coral reefs help protect the KSA coast
KING ABDULLAH UNIVERSITY OF SCIENCE & TECHNOLOGY (KAUST)
Prediction of storm surges and peak wave heights using advanced high-resolution modeling reveals the important role of offshore reefs in protecting coastal zones. The findings by KAUST researchers provide valuable design criteria for city planning in the King Abdullah Economic City (KAEC) coastal zone and highlight the economic and disaster-mitigating imperative to conserve the Red Sea's coral reefs.
"The original task was to model the maximum wave heights to set the minimum safe floor elevation for structures and roadway design in the city," says Sabique Langodan from KAUST's Red Sea Modeling and Prediction Group. "Yet with the wealth of wave and water-level observations and accurate bathymetry (water depth) near the coastline, combined with the advanced modeling and supercomputing capabilities available to us at KAUST, we extended the study to investigate the role of coral reefs in modulating the wave climate of this reef-sheltered region."
To accurately predict extreme wave heights it is necessary to model how waves transform as they pass across reefs and the shallow sea floor using long-term wave data. Many inputs go into the simulation, including a model of the physical wave transformation process, bathymetry, atmospheric forcing and sea circulation. Just as important, however, is the simulation architecture and the computational platform because they determine the resolution and accuracy of the results.
"We configured a high-resolution model using an unstructured grid, which allows us to vary the resolution of the model over the domain, from 60 kilometer cells out to sea, to cells as small as 60 meters near the coastline," says Langodan.
The researchers used a coupled wave and circulation model to account for changes in wave heights resulting from variations in water levels and currents. They combined this with meteorological fields derived from a high-resolution regional atmospheric model.
"Our high-resolution study allowed the minimum safe elevation in KAEC to be revised lower, from 4.0 meters to 2.3 meters," says group leader Ibrahim Hoteit. "Although a relatively small drop, this leads to a saving of about 90 million cubic meters of fill material equating to about 500 million USD."
However, the study also showed that the lowered safe elevation depends on the presence of the coral reefs located off the Red Sea coast, which act as a natural breakwater to provide protection to coastal areas against hazards, such as wave runup, overtopping, flooding and erosion.
"The reefs reduce wave heights by half at the coastline," says co-author Omar Knio. "Reef?protected coastlines could still be at risk of larger waves if the coastal protection offered by reefs is reduced by coral degradation or sea level rise."
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Why are plants green?
UC Riverside-led research team's model to explain photosynthesis lays out the next challenging phase of research on how green plants transform light energy into chemical energy
UNIVERSITY OF CALIFORNIA - RIVERSIDE
IMAGE: UC RIVERSIDE-LED RESEARCH TEAM'S MODEL TO EXPLAIN PHOTOSYNTHESIS LAYS OUT THE NEXT CHALLENGING PHASE OF RESEARCH ON HOW GREEN PLANTS TRANSFORM LIGHT ENERGY INTO CHEMICAL ENERGY. view more
CREDIT: GABOR LAB, UC RIVERSIDE.
RIVERSIDE, Calif. -- When sunlight shining on a leaf changes rapidly, plants must protect themselves from the ensuing sudden surges of solar energy. To cope with these changes, photosynthetic organisms -- from plants to bacteria -- have developed numerous tactics. Scientists have been unable, however, to identify the underlying design principle.
An international team of scientists, led by physicist Nathaniel M. Gabor at the University of California, Riverside, has now constructed a model that reproduces a general feature of photosynthetic light harvesting, observed across many photosynthetic organisms.
Light harvesting is the collection of solar energy by protein-bound chlorophyll molecules. In photosynthesis -- the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water -- light energy harvesting begins with sunlight absorption.
The researchers' model borrows ideas from the science of complex networks, a field of study that explores efficient operation in cellphone networks, brains, and the power grid. The model describes a simple network that is able to input light of two different colors, yet output a steady rate of solar power. This unusual choice of only two inputs has remarkable consequences.
"Our model shows that by absorbing only very specific colors of light, photosynthetic organisms may automatically protect themselves against sudden changes -- or 'noise' -- in solar energy, resulting in remarkably efficient power conversion," said Gabor, an associate professor of physics and astronomy, who led the study appearing today in the journal Science. "Green plants appear green and purple bacteria appear purple because only specific regions of the spectrum from which they absorb are suited for protection against rapidly changing solar energy."
Gabor first began thinking about photosynthesis research more than a decade ago, when he was a doctoral student at Cornell University. He wondered why plants rejected green light, the most intense solar light. Over the years, he worked with physicists and biologists worldwide to learn more about statistical methods and the quantum biology of photosynthesis.
Richard Cogdell, a renowned botanist at the University of Glasgow in the United Kingdom and a coauthor on the research paper, encouraged Gabor to extend the model to include a wider range of photosynthetic organisms that grow in environments where the incident solar spectrum is very different.
"Excitingly, we were then able to show that the model worked in other photosynthetic organisms besides green plants, and that the model identified a general and fundamental property of photosynthetic light harvesting," he said. "Our study shows how, by choosing where you absorb solar energy in relation to the incident solar spectrum, you can minimize the noise on the output -- information that can be used to enhance the performance of solar cells."
Coauthor Rienk van Grondelle, an influential experimental physicist at Vrije Universiteit Amsterdam in the Netherlands who works on the primary physical processes of photosynthesis, said the team found the absorption spectra of certain photosynthetic systems select certain spectral excitation regions that cancel the noise and maximize the energy stored.
"This very simple design principle could also be applied in the design of human-made solar cells," said van Grondelle, who has vast experience with photosynthetic light harvesting.
Gabor explained that plants and other photosynthetic organisms have a wide variety of tactics to prevent damage due to overexposure to the sun, ranging from molecular mechanisms of energy release to physical movement of the leaf to track the sun. Plants have even developed effective protection against UV light, just as in sunscreen.
"In the complex process of photosynthesis, it is clear that protecting the organism from overexposure is the driving factor in successful energy production, and this is the inspiration we used to develop our model," he said. "Our model incorporates relatively simple physics, yet it is consistent with a vast set of observations in biology. This is remarkably rare. If our model holds up to continued experiments, we may find even more agreement between theory and observations, giving rich insight into the inner workings of nature."
To construct the model, Gabor and his colleagues applied straightforward physics of networks to the complex details of biology, and were able to make clear, quantitative, and generic statements about highly diverse photosynthetic organisms.
"Our model is the first hypothesis-driven explanation for why plants are green, and we give a roadmap to test the model through more detailed experiments," Gabor said.
Photosynthesis may be thought of as a kitchen sink, Gabor added, where a faucet flows water in and a drain allows the water to flow out. If the flow into the sink is much bigger than the outward flow, the sink overflows and the water spills all over the floor.
"In photosynthesis, if the flow of solar power into the light harvesting network is significantly larger than the flow out, the photosynthetic network must adapt to reduce the sudden over-flow of energy," he said. "When the network fails to manage these fluctuations, the organism attempts to expel the extra energy. In doing so, the organism undergoes oxidative stress, which damages cells."
The researchers were surprised by how general and simple their model is.
"Nature will always surprise you," Gabor said. "Something that seems so complicated and complex might operate based on a few basic rules. We applied the model to organisms in different photosynthetic niches and continue to reproduce accurate absorption spectra. In biology, there are exceptions to every rule, so much so that finding a rule is usually very difficult. Surprisingly, we seem to have found one of the rules of photosynthetic life."
Gabor noted that over the last several decades, photosynthesis research has focused mainly on the structure and function of the microscopic components of the photosynthetic process.
"Biologists know well that biological systems are not generally finely tuned given the fact that organisms have little control over their external conditions," he said. "This contradiction has so far been unaddressed because no model exists that connects microscopic processes with macroscopic properties. Our work represents the first quantitative physical model that tackles this contradiction."
Next, supported by several recent grants, the researchers will design a novel microscopy technique to test their ideas and advance the technology of photo-biology experiments using quantum optics tools.
"There's a lot out there to understand about nature, and it only looks more beautiful as we unravel its mysteries," Gabor said.
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Gabor, Cogdell, and van Grondelle were joined in the research by Trevor B. Arp, Jed Kistner-Morris, and Vivek Aji at UCR.
The research was supported by the Air Force Office of Scientific Research Young Investigator Program, the National Science Foundation, and through a U.S. Department of the Navy's Historically Black Colleges and Universities/Minority Institutions award. Gabor was also supported through a Cottrell Scholar Award and a Canadian Institute for Advanced Research Azrieli Global Scholar Award. Other sources of funding were the NASA MUREP Institutional Research Opportunity program, the U.S. Department of Energy, the Biotechnological and Biological Sciences Research Council, the Royal Netherlands Academy of Arts and Sciences, and the Canadian Institute for Advanced Research.
The research paper is titled, "Quieting a noisy antenna reproduces photosynthetic light harvesting spectra."
The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment is more than 24,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of almost $2 billion. To learn more, email news@ucr.edu.
An international team of scientists,
Four new species of giant single-celled organisms discovered on Pacific seafloor
UNIVERSITY OF HAWAII AT MANOA
IMAGE: MOANAMMINA SEMICIRCULARIS ON THE SEAFLOOR PRIOR TO COLLECTION BY ROV. view more
CREDIT: JENNIFER DURDEN AND CRAIG SMITH, DEEPCCZ PROJECT.
Two new genera and four new species of giant, single-celled xenophyophores (protozoans belonging to a group called the foraminifera) were discovered in the deep Pacific Ocean during a joint project between scientists at the National Oceanography Centre, UK (NOC), the University of Hawai'i, and the University of Geneva. 'Moana' has inspired the name Moanammina for one of the new genera, while the second has been named Abyssalia in recognition of its abyssal habitat.
The species were described, based on morphology and genetic data, from specimens collected with the University of Hawai'i's Remotely Operated Vehicle Lu'ukai on an expedition to the western Clarion Clipperton Zone (CCZ) aboard the RV Kilo Moana in 2018. The seabed in this area is over three miles deep. The CCZ occupies a vast swathe of the Pacific Ocean with extensive seafloor polymetallic nodule deposits, and is targeted for deep-sea mining.
"We were excited to find these beautiful new xenophyophores," said Andrew Gooday, professor at NOC and lead author of the recently published findings. "It seemed appropriate to name one after 'Moana', a Hawaiian word meaning ocean. Xenophyophores are one of the most common types of large organism found on the CCZ abyssal plains, so the name of the second genus was chosen to reflect this."
Like some other types of foraminifera, xenophyophores construct shells, called tests, composed of particles that they obtain from the surrounding environment. These are often elaborate structures that can reach sizes of four inches or more.
Moanammina semicircularis sp. nov., the new species of the new genus, has a stalked, fan-shaped test, around three inches tall and three and one-half inches wide. Two other new species, Abyssalia foliformis sp. nov. and Abyssalia sphaerica sp. nov., have tests that resemble a flat leaf and an almost perfect sphere, respectively. They are remarkable for being constructed entirely of glass sponge spicules. The fourth new species is Psammina tenuis sp. nov., which has a delicate, thin, plate-like test.
"These four new species and two new genera have increased the number of described xenophyophores in the CCZ abyss to 17 (22% of the global total for this group), with many more known but still undescribed," said Gooday. "This part of the Pacific Ocean is clearly a hotspot of xenophyophore diversity."
"The abundance and diversity of these giant single-celled organisms is truly amazing!" said oceanographer Craig Smith from the UH Mānoa School of Ocean and Earth Science and Technology (SOEST), co-author and Chief Scientist of the RV Kilo Moana cruise on which the xenophyophores were discovered.
"We see them everywhere on the seafloor in many different shapes and sizes. They clearly are very important members of the rich biological communities living in the CCZ. Among other things they provide microhabitats and potential food sources for other organisms. We need to learn much more about the ecology these weird protozoans if we wish to fully understand how seafloor mining might impact these seafloor communities."
Moanammina semicircularis is genetically identical to another specimen found in 2017 in the eastern CCZ. Thus, this study provided the first genetic confirmation of wide geographic ranges (at least ~2,300 miles) for an abyssal xenophyophore species.
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More evidence of causal link between air pollution and early death
Study of more than 68 million older Americans using state-of-the-art analyses suggests that US air pollution standards are not protective enough
HARVARD T.H. CHAN SCHOOL OF PUBLIC HEALTH
Boston, MA - Strengthening U.S. air quality standards for fine particulate pollution to be in compliance with current World Health Association (WHO) guidelines could save more than 140,000 lives over the course of a decade, according to a new study from Harvard T.H. Chan School of Public Health.
The study, published June 26, 2020 in Sciences Advances, provides the most comprehensive evidence to date of the causal link between long-term exposure to fine particulate (PM2.5) air pollution and premature death, according to the authors.
"Our new study included the largest-ever dataset of older Americans and used multiple analytical methods, including statistical methods for causal inference, to show that current U.S. standards for PM2.5 concentrations are not protective enough and should be lowered to ensure that vulnerable populations, such as the elderly, are safe," said doctoral student Xiao Wu, a co-author of the study.
The new research builds on a 2017 study that showed that long-term exposure to PM2.5 pollution and ozone, even at levels below current U.S. air quality standards, increases the risk of premature death among the elderly in the U.S.
For the new study, researchers looked at 16 years' worth of data from 68.5 million Medicare enrollees--97% of Americans over the age of 65--adjusting for factors such as body mass index, smoking, ethnicity, income, and education. They matched participants' zip codes with air pollution data gathered from locations across the U.S. In estimating daily levels of PM2.5 air pollution for each zip code, the researchers also took into account satellite data, land-use information, weather variables, and other factors. They used two traditional statistical approaches as well as three state-of-the-art approaches aimed at teasing out cause and effect.
Results were consistent across all five different types of analyses, offering what authors called "the most robust and reproducible evidence to date" on the causal link between exposure to PM2.5 and mortality among Medicare enrollees--even at levels below the current U.S. air quality standard of 12 μg/m3 (12 micrograms per cubic meter) per year.
The authors found that an annual decrease of 10 μg/m3 in PM2.5 pollution would lead to a 6%-7% decrease in mortality risk. Based on that finding, they estimated that if the U.S. lowered its annual PM2.5 standard to 10 μg/m3--the WHO annual guideline--143,257 lives would be saved in one decade.
The authors included additional analyses focused on causation, which address criticisms that traditional analytical methods are not sufficient to inform revisions of national air quality standards. The new analyses enabled the researchers, in effect, to mimic a randomized study--considered the gold standard in assessing causality--thereby strengthening the finding of a link between air pollution and early death.
"The Environmental Protection Agency has proposed retaining current national air quality standards. But, as our new analysis shows, the current standards aren't protective enough, and strengthening them could save thousands of lives. With the public comment period for the EPA proposal ending on June 29, we hope our results can inform policymakers' decisions about potentially updating the standards," said co-author Francesca Dominici, Clarence James Gamble Professor of Biostatistics, Population, and Data Science.
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Other Harvard Chan School co-authors of the study included research scientist Danielle Braun and Joel Schwartz, professor of environmental epidemiology.
Funding for the study came from NIH grants R01 ES024332-01A1, P50 MD010428, R21 ES024012, R01 ES026217, R01 ES028033, MD012769, R01 ES030616, and P30 ES09089; HEI grant 4953-RFA14-3/16-4; and USEPA grants 83587201-0 and RD-83479801.
"Evaluating the Impact of Long-term Exposure to Fine Particulate Matter on Mortality Among the Elderly," Xiao Wu, Danielle Braun, Marianthi-Anna Kioumourtzoglou, Francesca Dominici, Science Advances, June 26, 2020, doi: 10.1126/sciadv.aba5692.
Visit the Harvard Chan School website for the latest news, press releases, and multimedia offerings.
Harvard T.H. Chan School of Public Health brings together dedicated experts from many disciplines to educate new generations of global health leaders and produce powerful ideas that improve the lives and health of people everywhere. As a community of leading scientists, educators, and students, we work together to take innovative ideas from the laboratory to people's lives--not only making scientific breakthroughs, but also working to change individual behaviors, public policies, and health care practices. Each year, more than 400 faculty members at Harvard Chan School teach 1,000-plus full-time students from around the world and train thousands more through online and executive education courses. Founded in 1913 as the Harvard-MIT School of Health Officers, the School is recognized as America's oldest professional training program in public health.
Report points to intergroup tensions from different interpretations of social distancing
UNIVERSITY OF BATH
Changes to lockdown measures in the UK and around the world in an effort to restart the economy could lead to wide disparity in how the public adheres to social distancing, according to a new report from psychologists at the University of Bath.
In a paper published in the British Journal of Social Psychology, the researchers warn of emerging tensions that will arise between groups who interpret messages about social distancing in different ways and the challenge this poses to policymakers.
They suggest that in March, strict lockdown guidelines supported by legal and policy changes, meant that most people adhered to the same mitigating practices including isolation and distancing.
Now that lockdown is easing in many parts of the world, with policies becoming more ambiguous, many practices now need to be negotiated on an interpersonal level, they argue. This means that ensuring compliance will increasingly rely on informal, social policing between individuals: both for those who do, versus those who do not uphold social distancing.
Over recent weeks in the UK, scenes of packed sunny beaches have filled newspapers, leading some to question the sense of others, labelled 'covidiots'. For the researchers this is a sign of mixed messaging surrounding the relaxation of lockdown with different interpretations by individuals.
They warn that morally blaming individuals for the impact of their behaviour on the pandemic - as evidenced in the recent threat to close beaches - may detract from a much-needed discussion over whether guidelines are fit for purpose and their effect on infection rates.
Equally, they draw attention to moral challenges faced by others who wish to maintain strict distancing or isolation and the challenges they now face under pressure to socialise without wanting to appear rude or overdramatic. The researchers suggest that how individuals continue to differently interpret public health messages about COVID-19 will lead to increased tensions between groups moving further into summer.
Lead researcher Annayah Prosser from the Department of Psychology at the University of Bath explains: "Strict lockdown guidelines meant that until recently everyone was adhering to the same mitigating practices such as isolation and distancing. However, now that lockdown is easing, and policy is becoming more ambiguous, many practices now need to be negotiated on an interpersonal level. For example, at the height of lockdown you didn't need to decline an invitation to a social gathering, because it was technically against the law. Now, if you decline an invitation, you could be perceived as rude, or as a 'do-gooder' who thinks they're better than everyone else."
In their report, the team outline how this person-to-person informal regulation poses difficulties for people who want to continue to maintain strict practices over time, who may increasingly face social derogation and ostracism from others who behave differently.
Annayah Prosser added: "Our main recommendation for individuals is to avoid portraying others as morally 'good' or 'bad' for their actions. People may have complex reasons for their behaviour, that may not be visible on sight or through a short social media post. These choices are tough and simplifying behaviour as 'good' or 'bad' without knowing the full story could lead to increased tensions and polarisation at a time when communities need to work together constructively to address the crisis."
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Spraying ethanol to nanofiber masks makes them reusable
POHANG UNIVERSITY OF SCIENCE & TECHNOLOGY (POSTECH)
IMAGE: EVALUATION OF BREATHING COMFORT BY INFRARED THERMAL CAMERA: (A) AIR AND MOISTURE TRANSMISSION AND (B) CO2 TRANSMISSION view more
CREDIT: HYUNG JOON CHA (POSTECH)
As the COVID-19 pandemic spreads around the world, masks have become an essential personal hygiene product as the first line of defense to protect one's respiratory system against the viruses and germs that spread through droplets in the air. It's a waste to dispose the masks after single use but troubling to reuse them. In light of this, a Korea-Japan research team recently released findings that compare and analyze the performance and functional differences of the filters used in masks after they are cleaned with ethanol.
Professor Hyung Joon Cha and doctoral candidates Jaeyun Lee and Yeonsu Jeong of the Department of Chemical Engineering at POSTECH and Professor Ick-Soo Kim and doctoral candidates Sana Ullah and Azeem Ullah of Shinshu University in Japan have been jointly analyzing the filtration efficiency, airflow rate, surface and morphological properties of the mask filters after they undergo cleaning treatments.
The research team verified the results using two types of cleaning procedures: First one was spraying 75% ethanol on the mask filter then air drying it, second was to saturate the filter in a 75% ethanol solution then air drying it.
A study of the melt-blown filters commonly used in N95 masks and the nanofiber filters produced by electrospinning found that just by spraying ethanol three or more times on the two materials or dipping them in the ethanol solution for more than five minutes effectively inhibit pathogens that can remain inside the mask filter.
The filtration efficiency of both materials in its first usage was measured at 95% and above, indicating that the wearer's respiratory system is effectively protected. It was also confirmed that surface of both materials do not allow water to adhere well, sufficiently hindering wetting by moisture or saliva (droplets).
However, the filtration efficiency of the melt-blown filter decreased by up to 64% when cleaned with ethanol solution and reused. On the other hand, the filtration efficiency of nanofiber filters when reused 10 times through ethanol spray cleaning or immersion in ethanol solution for 24 hours maintained nearly consistent high filtration efficiency.
Schematic diagram on spraying and dipping treatments of face mask filters using 75% ethanol for evaluation of reusability
The joint research team attributed this difference to the decrease in static electricity in the filters after cleaning. Melt-blown filters rely in part on the electrostatic effect of the surface when filtering particles. However, nanofiber does not rely on static electricity but filters according to the morphological properties and pore size of the surface, and is not deformed by ethanol.
Moreover, nanofiber filters have better breathability because they have much higher heat and carbon dioxide emission capabilities compared to the melt-blown filters. Biosafety tests using human skin and vascular cells also confirmed no cytotoxicity.
In summary, both mask filters have similar filtration performance in its initial use, but only nanofiber filters can be reused multiple times through a simple ethanol cleaning process.
POSTECH Professor Hyung Joon Cha explained the significance of the research by commenting, "This research is an experiment that has verified the biosafety of nanofiber masks - which have recently become a hot issue - and their ability to maintain filtration efficiency after cleaning."
In addition, Professor Ick-Soo Kim of Shinshu University added, "I hope the nanofiber masks will help everyone as a means of preventing contagion in the possible second or third wave of COVID-19.
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These research findings were recently published online in the international journal ACS Applied Nano Materials published by the American Chemical Society.
Ladder falls have long-lasting consequences for older blokes
UNIVERSITY OF QUEENSLAND
IT only takes a moment to fall off a ladder, but the psychological impacts are long-lasting, particularly for older males.
In the world's first study of long-term impacts from ladder falls, Queensland researchers have found half of fallers experience a deterioration in their psychological wellbeing for at least six months after the incident.
The University of Queensland's Dr Rob Eley said those who fell experienced sleeping problems, anxiety, depression and pain well after checking out of hospital.
"Ladder falls go far beyond that of the physical injury; they significantly impact a person's mental health and the whole family," Dr Eley said.
"It's frustrating because ladder-related falls are frequently preventable, yet they're a common cause of injuries presented at the emergency department.
"Our study found males over 55 years old are particularly at risk, making up more than half of all our ladder-related fall cases."
The researchers followed 134 Queenslanders who presented to emergency at Princess Alexandra and Nambour General Hospitals between October 2015 and October 2016 as a result of a fall from a ladder.
The team used the Assessment of Quality of Life (AQoL) scale to measure the subjects' physical and psychological recovery over time.
The patients spent an average of five days in hospital with the most common injuries including spinal fractures, rib fractures, tibia or fibula fractures, radius or ulna fractures, pelvic fractures, and traumatic pneumothorax.
The study found that most injuries occurred in non-occupational settings during home maintenance.
Of those who were employed at the time, 80 per cent required at least four weeks off work, and 16 per cent were unable to return or perform their normal function after six months.
Dr Eley said the study highlighted the need for improved safety designs and injury prevention strategies.
"Our research reinforces the need for mandated safety instructions for ladders, as well as safety features like rubber feet, hooks, extender arms, fasteners and stabilisers," Dr Eley said.
"We suggest that at the place of purchase, older men are targeted to reinforce safety instructions, and perhaps are provided with mandatory stabilising features.
"The community also needs to do more to educate people that it's OK to request help or employ home service contractors to complete tasks around the home that require a ladder.
"Ladder falls are frequently preventable and our findings demonstrate the need for preventative measures to be taken."
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This study was conducted with Queensland University of Technology and Queensland Health, funded by the Emergency Medicine Foundation, and is published in the journal, PLOS ONE. DOI: 10.1371/journal.pone.0235092.
IMAGE: AN ANIMATION DEPICTING SPECIFIC GENOMIC VARIANTS THAT CAUSE A DISEASE CALLED FAMILIAL MEDITERRANEAN FEVER (FMF) MAY ALSO CONFER INCREASED RESILIENCE TO THE PLAGUE. view more
CREDIT: CREDIT: ERNESTO DEL AGUILA III, NHGRI.
Ancient disease may increase resilience to bubonic plague
Genomic variants that cause common periodic fever have spread in Mediterranean populations over centuries, potentially protecting people from the plague
NIH/NATIONAL HUMAN GENOME RESEARCH INSTITUTE
Researchers have discovered that Mediterranean populations may be more susceptible to an autoinflammatory disease because of evolutionary pressure to survive the bubonic plague. The study, carried out by scientists at the National Human Genome Research Institute (NHGRI), part of the National Institutes of Health, determined that specific genomic variants that cause a disease called familial Mediterranean fever (FMF) may also confer increased resilience to the plague.
The researchers suggest that because of this potential advantage, FMF-causing genomic variants have been positively selected for in Mediterranean populations over centuries. The findings were published in the journal Nature Immunology.
Over centuries, a biological arms race has been fought between humans and microbial pathogens. This evolutionary battle is between the human immune system and microorganisms trying to invade our bodies. Microbes affect the human genome in many ways. For example, they can influence some of the genomic variation that accumulates in human populations over time.
"In this era of a new pandemic, understanding the interplay between microbes and humans is ever critical," said Dr. Dan Kastner, NHGRI scientific director and a co-author on the paper. "We can witness evolution playing out before our very eyes."
One such microbe is Yersinia pestis, the bacterial agent responsible for a series of well-documented bubonic plague epidemics that led to over 50 million deaths.
FMF, like the plague, is an ancient disease. It is the most common periodic fever syndrome, and symptoms of FMF include recurrent fevers, arthritis, rashes and inflammation of the tissues that line the heart, lungs, and abdominal organs. FMF may also lead to renal failure and death without treatment. The disease appears across the Mediterranean region and mostly affects Turkish, Jewish, Armenian and Arab populations.
Genomic variants in the MEFV gene cause FMF. MEFV encodes a protein called pyrin. In healthy people, pyrin plays a role in the inflammatory response of the body. Pyrin is activated when there is an immune response (for example, in the event of an infection). Pyrin increases inflammation and the production of inflammation-related molecules.
In contrast, FMF patients produce abnormal pyrin because of genomic variants (mutations) in the MEFV gene. Mutated pyrin does not need an infection or other immune trigger to be activated; rather, it is able to directly predispose people to seemingly unprovoked episodes of fever and inflammation.
The MEFV mutations also have other usual properties. Researchers have discovered that people with only one copy of a MEFV genomic variant that causes FMF do not get the disease. Also, prior to effective treatment, those with two copies have a high mortality rate by the age of 40 but usually live long enough to have children.
Despite the lower survival rate, almost 10% of Turks, Jews, Arabs and Armenians carry at least one copy of an FMF-causing genomic variant. If chance were the only factor, that percentage would be much lower.
The researchers proposed that this higher percentage was a consequence of positive natural selection, which is an evolutionary process that drives an increase in specific genomic variants and traits that are advantageous in some way.
"Just like sickle cell trait is positively selected for because it protects against malaria, we speculated that the mutant pyrin in FMF might be helping the Mediterranean population in some way," said Jae Jin Chae, Ph.D., senior author of the paper and a staff scientist in NHGRI's Metabolic, Cardiovascular and Inflammatory Disease Genomics Branch. "The mutant pyrin may be protecting them from some fatal infection."
The team turned to Yersinia pestis, the infamous bubonic plague-causing bacterium, as a possible candidate for driving the evolutionary selection for FMF mutations in the Mediterranean population.
It turns out Yersinia pestis contains a particular molecule that represses the function of pyrin in healthy individuals. In doing so, the pathogen suppresses the body's inflammatory response to the infection. This way, the body cannot fight back.
"Inflammation is a process in which white blood cells protect the body from infection. From the host's point of view, inflammation helps us survive. From the bacteria's point of view, inflammation is something to be evaded by any means available," said Daniel Shriner, Ph.D., staff scientist in the Center for Research on Genomics and Global Health at NHGRI.
Researchers were struck by the fact that Yersinia pestis affects the very protein that is mutated in FMF. They considered the possibility that FMF-causing genomic variants may protect individuals from the bubonic plague caused by Yersinia pestis.
The idea that evolution would push for one disease in a group to fight another may seem counterintuitive. But it comes down to what is the least bad option.
The average mortality rate of people with bubonic plague over centuries has been as high as 66%, while, even with a carrier frequency of 10%, less than 1% of the population has FMF. Theoretically, the evolutionary odds are in the latter's favor.
But first, the team had to verify if two of the genomic variants that cause FMF had indeed undergone positive selection in Mediterranean populations.
For this, they performed genetic analysis on a large cohort of 2,313 Turkish individuals. They also examined genomes from 352 ancient archaeological samples, including 261 from before the Christian era. The researchers tested for the presence of two FMF-causing genomic variants in both groups of samples. They also used population genetics principles and mathematical modeling to predict how the frequency of FMF-causing genomic variants changed over generations.
"We found that both FMF-causing genomic variants arose more than 2,000 years ago, before the Justinian Plague and the Black Death. Both variants were associated with evidence of positive selection," said Elaine Remmers, Ph.D., associate investigator in NHGRI's Metabolic, Cardiovascular and Inflammatory Disease Genomics Branch.
Researchers then studied how Yersinia pestis interacts with FMF-causing genomic variants. They took samples of particular white blood cells from FMF patients. In addition, they took samples from people who carry just one copy of the genomic variants (hence, do not get the disease).
The team found that Yersinia pestis does not reduce inflammation in white blood cells acquired from FMF patients and people with one copy of FMF-causing genomic variants. This finding is in stark contrast to the fact that Yersinia pestis reduces inflammation in cells without FMF-associated mutations.
The researchers thought that if Yersinia pestis does not reduce inflammation in people with FMF, then perhaps this could potentially increase patients' survival rate when infected by the pathogen.
To test this hypothesis, the researchers genetically engineered mice with FMF-causing genomic variants. They infected both healthy and genetically engineered mice with Yersinia pestis. Their results showed that infected mice with the FMF-causing genomic variant had significantly increased survival as compared to infected healthy mice.
These findings, in combination, indicate that over centuries, FMF-causing genomic variants positively selected in Turkish populations play a role in providing resistance to Yersinia pestis infection. Whether the same is true for other Mediterranean populations remains to be seen. The study offers a glimpse into the unexpected and long-lasting influence of microbes on human biology.
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BU study: Nearly half of US youth have been stalked/harassed by partners
BOSTON UNIVERSITY SCHOOL OF MEDICINE
A new, first-of-its-kind Boston University School of Public Health (BUSPH) study finds that 48% of 12-18-year-olds who have been in a relationship have been stalked or harassed by a partner, and 42% have stalked or harassed a partner.
Published in the journal Youth & Society, the analysis is part of the first nationally-representative study of non-physical youth dating abuse.
"These victimization and perpetration numbers are unacceptably high," says study lead author Dr. Emily Rothman, professor of community health sciences at BUSPH. "Unfortunately, they are in line with estimates of similar problems like dating and sexual violence victimization, so they are both shocking and unsurprising at the same time."
Previous research shows that harassing and stalking behaviors, including destroying belongings or going through social media accounts, can lead to physical violence, Rothman says.
But perhaps especially in the time of COVID, non-physical dating abuse needs to be recognized as real and harmful in its own right, she says.
"Adolescents have already been fully aware of how harmful online forms of abuse can be--that it's valid to be interested in that and to try to address it," Rothman says. "COVID has in some ways made parents, teachers, and other adults more willing to see, right now, that what we do online matters and is fully part of our real lives."
Rothman and colleagues from NORC at the University of Chicago used data from the ongoing Survey on Teen Relationships and Intimate Violence (STRiV) study to look at responses from 148 boys and 172 girls who were currently in relationships or had been in relationships in the past year. The survey asked teens if a partner had ever followed or spied on them, damaged something that belonged to them, or gone through their online accounts. The survey also asked the teens if they had ever done any of these things to a partner.
They found that rates of perpetration and victimization were similar for boys and girls: 46.5% of boys and 50.6% of girls reported stalking or harassing a partner, and 44.6% of boys and 51.1% of girls reported a partner doing these things to them.
The researchers analyzed and controlled for a range of other factors to better understand why particular teens may be at higher risk of perpetration, victimization, or both.
Among boys, having worse relationships with parents and living in neighborhoods with higher rates of violent crime were both associated with higher risk of perpetration. Among girls, being in relationships at younger age, living in neighborhoods with higher rates of violent crime, using marijuana, and using alcohol were associated with higher risk of victimization and perpetration. By race/ethnicity, the researchers found that Latino boys and Black girls faced higher risk of both victimization and perpetration.
Further research will need to untangle these associations, but Rothman says the findings show that dating abuse is shaped by forces larger than the individual.
"We know from intervention research that the way to prevent stalking and harassment, or sexual and dating violence, is partly about addressing how young people think about relationships, gender norms, and improving their social-emotional skills, but these are also influenced by the context in which they are operating," she says.
"So, addressing racism, poverty, homophobia, misogyny, and disability-related discrimination is part of the solution, too."
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About the Boston University School of Public Health
Founded in 1976, the Boston University School of Public Health is one of the top five ranked private schools of public health in the world. It offers master's- and doctoral-level education in public health. The faculty in six departments conduct policy-changing public health research around the world, with the mission of improving the health of populations--especially the disadvantaged, underserved, and vulnerable--locally and globally.
Microbiome confers resistance to cholera
Not everyone exposed to infectious diarrhea-causing bacteria gets sick
UNIVERSITY OF CALIFORNIA - RIVERSIDE
IMAGE: VIBRIO CHOLERAE BACTERIUM, WHICH IS RESPONSIBLE FOR CAUSING CHOLERA. view more
CREDIT: CENTERS FOR DISEASE CONTROL AND PREVENTION
Cholera can kill within hours if left untreated, and it sickens as many as 4 million people a year. In a new article in the journal Cell, researchers describe how gut bacteria helps people resist the disease.
Bacteria live everywhere on the planet -- even inside the human body. UCR microbiologist Ansel Hsiao studies whether the bacteria living in our bodies, collectively known as the human microbiome, can protect people from diseases caused by external bacteria such as Vibrio cholerae, which lives in waterways and causes cholera.
Hsiao's team examined the gut microbiomes from people in Bangladesh, where many suffer from cholera as a result of contaminated food, water and poor sanitation infrastructure. "When people get sick, the diarrhea gets flushed into water systems that people drink from, and it's a negative cycle," Hsiao explained.
His team wanted to see whether prior infections or other stresses, like malnutrition, make people more vulnerable, as compared to Americans who don't face these same pressures.
The findings surprised the group, which expected stressed Bangladeshi microbiomes would allow for higher rates of infection. Instead, they saw infection rates varied greatly among individuals in both populations, suggesting susceptibility is based on a person's unique microbiome composition -- not the place they're from.
Vibrio cholerae spends most of its time outside of humans in aquatic environments. It doesn't usually encounter bile, which mammals produce to help digest fats after a meal.
"Because bile is specific to the intestines of humans and animals, many microorganisms, including cholerae, have evolved ways to deal with it," Hsiao said.
Once Vibrio cholerae enters a body, the presence of bile and lack of oxygen in the gut triggers previously dormant genes that enable it to survive in its human host. These genes are responsible for cholera's virulence, helping Vibrio cholerae attach to intestinal walls and cause diarrhea.
Hsiao's team identified one bacterium in the human microbiome, Blautia obeum, that can deactivate the cholera bacterium's disease-causing mechanisms, preventing it from colonizing the intestines. They also figured out how this feat is accomplished.
Cholera patients in Haiti, where an outbreak of cholera occurred after a 7.0 earthquake in 2010
Kendra Helmer/USAID
Blautia obeum produces an enzyme that degrades salts in bile, which Vibrio cholerae uses as signals to control gene activity. When these bile salts are corrupted, the cholera-causing bacteria does not receive the signal to activate the dormant genes that cause infection.
Since it's become clear that more Blautia obeum makes people less susceptible to cholera, a focus of future studies will be how to increase its presence in the gut. "We are extremely interested now in learning which environmental factors, such as diet, can boost levels of obeum," Hsiao said.
Similar studies are also underway with regard to the virus causing another global pandemic -- SARS-CoV-2. Hsiao is collaborating with several groups trying to understand how the microbiome changes with COVID-19 infection.
"One day, we may also understand whether and how the microbiome affects COVID-19 and makes people resistant to other illnesses we don't currently have treatments for," Hsiao said.
