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)
Sunday, July 23, 2023
A defense against attacks on unmanned ground and aerial vehicles
UTA research team investigating ways to thwart cyberattacks
A University of Texas at Arlington engineering researcher is working on defenses that could thwart cyberattacks against networks of self-driving cars and unmanned aerial vehicles.
Animesh Chakravarthy, associate professor in the Department of Mechanical and Aerospace Engineering (MAE), is the principal investigator on an approximately $800,000 U.S. Department of Defense grant titled “Resilient Multi-Vehicle Networks.” MAE Professor Kamesh Subbarao, and Bill Beksi, assistant professor in the Department of Computer Science and Engineering, are co-principal investigators.
“If hackers find a way to affect 10 out of 100 self-driving cars in a given area, they might have an impact on all 100 cars because the 10 hacked cars would have a ripple effect on the other vehicles,” Chakravarthy said. “We have to make these networks of vehicles resilient to such attacks. This project is meant to detect occurrences as they happen, then provide countermeasures.
Chakravarthy and his colleagues also will attempt to determine costs associated with cyberattacks on automated vehicles, including how much time and money are wasted in traffic or in waiting for accidents to clear.
MAE Chair Erian Armanios said Chakravarthy’s research will be vital to the growth of unmanned vehicle networks.
“You need to ensure smooth and safe operations of those vehicle networks,” Armanios said. “The work of Chakravarthy, Subbarao and Beksi in this grant will achieve that.”
Dark SRF experiment at Fermilab demonstrates ultra-sensitivity for dark photon searches
IMAGE: STANDING AROUND THE DARK SRF EXPERIMENT FROM LEFT TO RIGHT ARE SQMS CENTER DIRECTOR ANNA GRASSELLINO, SQMS SCIENCE THRUST LEADER RONI HARNIK AND SQMS TECHNOLOGY THRUST LEADER ALEXANDER ROMANENKO.view more
CREDIT: PHOTO: REIDAR HAHN, FERMILAB
Scientists working on the Dark SRF experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory have demonstrated unprecedented sensitivity in an experimental setup used to search for theorized particles called dark photons.
Researchers trapped ordinary, massless photons in devices called superconducting radio frequency cavities to look for the transition of those photons into their hypothesized dark sector counterparts. The experiment has put the world’s best constraint on the dark photon existence in a specific mass range, as recently published in Physical Review Letters.
“The dark photon is a copy similar to the photon we know and love, but with a few variations,” said Roni Harnik, a researcher at the Fermilab-hosted Superconducting Quantum Materials and Systems Center and co-author of this study.
Light that allows us to see the ordinary matter in our world is made of particles called photons. But ordinary matter only accounts for a small fraction of all matter. Our universe is filled with an unknown substance called dark matter, which comprises 85% of all matter. The Standard Model that describes the known particles and forces is incomplete.
In theorists’ simplest version, one undiscovered type of dark matter particle could account for all the dark matter in the universe. But many scientists suspect that the dark sector in the universe has many different particles and forces; some of them might have hidden interactions with ordinary matter particles and forces.
Just as the electron has copies that differ in some ways, including the muon and tau, the dark photon would be different from the regular photon and would have mass. Theoretically, once produced, photons and dark photons could transform into each other at a specific rate set by the dark photon’s properties.
Innovative use of SRF cavities
To look for dark photons, researchers perform a type of experiment called a light-shining-through-wall experiment. This approach uses two hollow, metallic cavities to detect the transformation of an ordinary photon into a dark matter photon. Scientists store ordinary photons in one cavity while leaving the other cavity empty. They then look for the emergence of photons in the empty cavity.
Fermilab researchers in the SQMS Center have years of expertise working with SRF cavities, which are used primarily in particle accelerators. SQMS Center researchers have now employed SRF cavities for other purposes, such as quantum computing and dark matter searches, due to their ability to store and harness electromagnetic energy with high efficiency.
“We were looking for other applications with superconducting radio frequency cavities, and I learned about these experiments where they use two copper cavities side-by-side to test for light shining through the wall,” said Alexander Romanenko, SQMS Center quantum technology thrust leader. “It was immediately clear to me that we could demonstrate greater sensitivity with SRF cavities than cavities used in previous experiments.”
This experiment marks the first demonstration of using SRF cavities to perform a light-shining-through-wall experiment.
The SRF cavities used by Romanenko and his collaborators are hollow chunks of niobium. When cooled to ultralow temperature, these cavities store photons, or packets of electromagnetic energy, very well. For the Dark SRF experiment, scientists cooled the SRF cavities in a bath of liquid helium to around 2 K, close to absolute zero.
At this temperature, electromagnetic energy flows effortlessly through niobium, which makes these cavities efficient at storing photons.
“We have been developing various schemes trying to handle the new opportunities and challenges brought in by this ultra-high-quality superconducting cavities for this light-shining-through-wall experiment,” said study co-author Zhen Liu, an SQMS Center physics and sensing team member from the University of Minnesota.
Researchers now can use SRF cavities with different resonance frequencies to cover various parts of the potential mass range for dark photons. This is because the peak sensitivity on the mass of the dark photon is directly related to the frequency of the regular photons stored in one of the SRF cavities.
“The team has done many follow-ups and cross-checks of the experiment,” said Liu, who worked on the data analysis and the verification design. “SRF cavities open many new search possibilities. The fact we covered new parameter regions for the dark photon’s mass shows their successfulness, competitiveness and great promise for the future.”
“The Dark SRF experiment has paved the way for a new class of experiments under exploration at the SQMS Center, where these very high Q cavities are employed as extremely sensitive detectors.” said Anna Grassellino, director of the SQMS Center and co-PI of the experiment. “From dark matter to gravitational waves searches, to fundamental tests of quantum mechanics, these world’s-highest-efficiency cavities will help us uncover hints of new physics.”
Fermi National Accelerator Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
JOURNAL
Physical Review Letters
The Lancet: People on ART with low but detectible levels of HIV viral load have almost zero risk of sexually transmitting the virus to others, in-depth review suggests
Systematic review of 8 studies in more than 7,700 serodiscordant couples in 25 countries finds people living with HIV with viral loads less than 1,000 copies/mL have almost zero risk of transmitting the virus to their sexual partners. Previous studies have not been able to confirm a lack of transmission risk above 200 copies/mL.
Systematic review also consolidates and reinforces previous studies that have found there is zero risk of transmitting the virus to sexual partners when people living with HIV have an undetectable viral load.
Of the more than 320 documented sexual HIV transmissions in the study, only two involved a partner with a viral load of less than 1,000 copies/mL. In both cases, viral load testing was performed at least 50 days before transmission took place.
At least 80% of transmissions involved a partner with HIV who had a viral load greater than 10,000 copies/mL.
The findings are published alongside a new WHO policy brief providing updated guidance for HIV treatment monitoring and accompanying supportive messaging regarding transmission risks.
Together the new study and policy brief advance global efforts to achieve undetectable viral loads by expanding antiretroviral therapy (ART) for all people living with HIV and reinforce the importance of decriminalising HIV and reducing stigma and discrimination for people living with HIV.
People living with HIV who maintain low – but still detectible – levels of the virus and adhere to their antiretroviral regimen have almost zero risk of transmitting it to their sexual partners, according to an analysis published in The Lancet. The study’s findings will be presented at an official satellite session ahead of the 12th International AIDS Society Conference on HIV Science (IAS 2023). [1]
Findings from the systematic review indicate the risk of sexual transmission of HIV is almost zero at viral loads of less than 1,000 copies of the virus per millilitre of blood—also commonly referred to as having a suppressed viral load. The systematic review also confirms that people living with HIV who have an undetectable viral load (not detected by the test used) have zero risk of transmitting HIV to their sexual partners.
A new policy brief from the World Health Organization (WHO), published alongside the research paper, provides updated sexual transmission prevention and viral load testing guidance to policymakers, public health professionals, and people living with HIV based on this analysis. This guidance aims to further prevent the transmission of HIV and ultimately support global efforts to achieve undetectable viral loads through antiretroviral therapy for all people living with HIV and to prevent onward transmission to their sexual partner(s) and children. [2]
Previous research has shown people living with HIV with viral loads below 200 copies/mL have zero risk of sexually transmitting the virus. However, until now, the risk of transmission at viral loads between 200 and 1000 copies/mL was less well defined.
The authors filled this knowledge gap by searching databases for all research studies published between January 2000 and November 2022 on sexual transmission of HIV at varying viral loads. In total, eight studies were included in the systematic review, providing data on 7,762 serodiscordant couples – in which one partner was living with HIV – across 25 countries.
Lead author Laura Broyles, MD, of the Global Health Impact Group (Atlanta, USA), said: “These findings are important as they indicate that it is extremely rare for people who maintain low levels of HIV to transmit it to their sexual partners. Crucially, this conclusion can promote the expansion of alternative viral load testing modalities that are more feasible in resource-limited settings. Improving access to routine viral load testing could ultimately help people with HIV live healthier lives and reduce transmission of the virus.” [3]
Taking daily medicine to treat HIV – antiretroviral therapy, or ART – lowers the amount of the virus in the body which preserves immune function and reduces morbidity and mortality associated with the virus and helps reduce HIV progression. Without ART, people living with HIV can have a viral load of 30,000 to more than 500,000 copies/mL, depending on the stage of infection. [4]
While using lab-based plasma sample methods provides the most sensitive viral load test results, such tests are not feasible in many parts of the world. However, the new findings support the greater use of simpler testing approaches, such as using dried blood spot samples, as they are effective at categorising viral loads for necessary clinical decision-making.
Of the 323 sexual transmissions of HIV detected across all eight studies, only two involved a partner with a viral load of less than 1000 copies/mL. In both cases, the viral load test was performed at least 50 days before transmission, suggesting individuals’ viral load may have risen in the period following the test. In studies that provided the full range of viral loads in partners with HIV, at least 80% of transmissions involved viral loads greater than 10,000 copies/mL.
Co-author Dr Lara Vojnov, of WHO, said: “The ultimate goal of antiretroviral therapy for people living with HIV is to maintain undetectable viral loads, which will improve their own health and prevent transmission to their sexual partners and children. But these new findings are also significant as they indicate that the risk of sexual transmission of HIV at low viral loads is almost zero. This provides a powerful opportunity to help destigmatise HIV, promote the benefits of adhering to antiretroviral therapy, and support people living with HIV.” [3]
The authors acknowledge some limitations to their study. Some of the data analysed were imprecise due to variations across the studies in the definitions of ‘low viral load’, and in the timing and frequency of viral load testing and patient follow-up. Today, HIV treatment is recommended for everyone living with HIV and very large sample sizes would be needed to develop more precise estimates given the extremely low number of transmissions.
Further, the findings do not apply to HIV transmission from mother to child, as the duration and intensity of exposure – during pregnancy, childbirth, and breastfeeding – is much higher. Differences also exist in the way the virus is passed from mother to child as compared with sexual transmission. Ensuring pregnant and breastfeeding women have undetectable viral loads throughout the entire exposure period is key to preventing new childhood HIV infections.
Writing in a linked Comment, co-authors Linda-Gail Bekker, Philip Smith, and Ntobeko A B Ntusi (who were not involved in the study) said, “Laura N Broyles and colleagues’ systematic review in The Lancet further supports the almost zero risk for sexual transmission of HIV at levels less than 1000 copies per mL…This evidence is relevant for at least three important reasons. First, it highlights the need for viral load testing scale-up in all settings where people are living with HIV and taking ART…Second, as pointed out by Broyles and colleagues, these data are probably the best that we will ever have. Standard of care now requires that individuals are offered life-saving ART regardless of viral load…Third, and most importantly, this study provides strong support for the global undetectable equals untransmittable (U=U) campaign. This campaign seeks to popularise the concept that individuals with undetectable viral loads are not infectious to sexual partners, thereby reducing stigma and improving quality of life.”
NOTES TO EDITORS
This study was funded by the Bill & Melinda Gates Foundation. It was conducted by researchers from the Global Health Impact Group and the World Health Organization.
The secret to protecting your memory may be a staple of a bodybuilder’s diet. RUSH researchers recently discovered that a muscle-building supplement called beta-hydroxy beta-methylbutyrate, also called HMB, may help protect memory, reduce plaques and ultimately help prevent the progression of Alzheimer’s disease.
HMB is not a prescription drug or a steroid, but an over-the-counter supplement that is available in sports and fitness stores. Bodybuilders regularly use HMB to increase exercise-induced gains in muscle size and strength while improving exercise performance. HMB is considered safe even after long-term use, with no known side effects.
“This may be one of the safest and the easiest approaches to halt disease progression and protect memory in Alzheimer’s disease patients,” said Kalipada Pahan, PhD, the Floyd A. Davis, MD, Professor of Neurology and professor of neurological sciences, biochemistry and pharmacology at RUSH Medical College.
Studies in mice with Alzheimer’s disease have shown that HMB successfully reduces plaques and increases factors for neuronal growth to protect learning and memory, according to neurological researchers at RUSH.
“Understanding how the disease works is important to developing effective drugs to protect the brain and stop the progression of Alzheimer’s disease,” Pahan said.
Previous studies indicate that a family of proteins known as neurotrophic factors are drastically decreased in the brains of people with Alzheimer’s disease and have been found to help in survival and function of neurons, which are cells that receive and send messages from the body to the brain and vice versa.
“Our study found that after oral consumption, HMB enters into the brain to increase these beneficial proteins, restore neuronal connections and improve memory and learning in mice with Alzheimer’s-like pathology, such as plaques and tangles,” Pahan said.
The study findings indicate that HMB stimulates a nuclear hormone receptor called PPARα within the brain that regulates the transport of fatty acids, which is key to the success of HMB as a neuroprotective supplement.
“If mouse results with HMB are replicated in Alzheimer’s disease patients, it would open up a promising avenue of treatment of this devastating neurodegenerative disease,” Pahan said.
Alzheimer's disease is an irreversible, progressive brain disease that slowly destroys memory and thinking skills and, eventually, even the ability to carry out the simplest tasks. In most people with Alzheimer's, symptoms first appear after age 60. Alzheimer's disease is the most common cause of dementia among older people, affecting as many as 6 million Americans and more than 10% of people age 65 and older. About two-thirds of Americans with Alzheimer’s disease are women.
Results from the study, funded by the National Institutes of Health, were recently published in the Cell Reports.
UNIVERSITY OF ILLINOIS GRAINGER COLLEGE OF ENGINEERING
Researchers have identified a number of chokepoints in U.S. agricultural and food supply chains through a study that improves our understanding of agri-food supply chain security and may aid policies aimed at enhancing its resilience. The work is presented in a paper published in the July 20, 2023, issue of the journal Nature Food, “Structural chokepoints determine the resilience of agri-food supply chains in the United States,” by authors including CEE Associate Professor Megan Konar and CEE Ph.D. student Deniz Berfin Karakoc.
The agricultural and food systems of the United States are critical for ensuring the stability of both domestic and global food systems, so it is essential to understand the structural resilience of the country’s agri-food supply chains to threats, researchers write. Because the United States plays a key role in a highly integrated global food system, the resilience and security of the U.S. food supply chain has implications for global food security. Additionally, agricultural and food system security and resilience is increasingly recognized as a non-traditional defense objective in the national security community and is critical to the mission of U.S. national defense agencies.
“We were inspired to perform this research due to the supply chain disruptions during the pandemic and in response to the Executive Order on America’s Supply Chains, which highlights the importance of supply chains for national security,” Konar says. “We hope this research can contribute to more resilient and secure food supply chains.”
Chokepoints are locations that are critical for distributing agri-food commodities throughout the country. While much research on agri-food supply chains has been from the perspective of industrial firms with a focus on logistics, cost-savings and resilience, the researchers took a national and global security perspective due to growing threats such as pandemics, extreme weather events, climate shocks, and cyber and terrorist attacks. The researchers employed a complex network approach to determine the chokepoints within the agri-food supply chains in the continental U.S. for the years 2007, 2012 and 2017. They found that chokepoints were generally consistent over time.
Co-authors also include Michael J. Puma of the Center for Climate Systems Research at Columbia University and Lav R. Varshney of the Department of Electrical and Computer Engineering at the University of Illinois Urbana-Champaign.
IMAGE: RESEARCHER CASSANDRA BOYD HOLDING GARLIC AND ONION, TWO FOODS THAT THE STUDY REVEALED TO BE DENSE IN PREBIOTICS.view more
CREDIT: CASSANDRA BOYD
There is growing evidence that consuming prebiotics — certain types of fiber often found in plants that stimulate beneficial bacteria in your gut — can help to maintain a healthy gut microbiome. In a new study, scientists estimated the prebiotic content of thousands of food types by using preexisting literature to find out which foods offer the highest prebiotic content.
According to the study, foods that pack the greatest prebiotic punch are dandelion greens, Jerusalem artichokes, garlic, leeks, and onions. In addition to supporting gut microbes, prebiotic rich foods contain high amounts of fiber — something most Americans do not get enough of.
Boyd will present the findings at NUTRITION 2023, the flagship annual meeting of the American Society for Nutrition held July 22–25 in Boston.
Prebiotics, which can be thought of as food for the microbiome, are different from probiotics, which contain live microorganisms. Both can potentially benefit microbiome health, but they work in different ways.
Studies have linked higher prebiotic intake with improved blood glucose regulation, better absorption of minerals like calcium, and markers of improved digestive and immune function. Although most dietary guidelines do not currently specify a recommended daily allowance for prebiotics, the International Scientific Association for Probiotics and Prebiotics — a non-profit scientific organization that established the currently held definition of prebiotics — recommends an intake of 5 grams per day.
For the study, researchers used previously published scientific findings to analyze the prebiotic content of 8,690 foods contained in the Food and Nutrient Database for Dietary Studies, a resource many scientists use to study nutrition and health.
About 37% of the foods in the database were found to contain prebiotics. Dandelion greens, Jerusalem artichoke, garlic, leeks, and onions had the greatest amounts, ranging from about 100-240 milligrams of prebiotics per gram of food (mg/g). Other prebiotic rich foods included onion rings, creamed onions, cowpeas, asparagus, and Kellogg's All-Bran cereal, each containing around 50-60 mg/g.
“The findings from our preliminary literature review suggest that onions and related foods contain multiple forms of prebiotics, leading to a larger total prebiotic content,” said Boyd. “Multiple forms of onions and related foods appear in a variety of dishes as both flavoring and main ingredients. These foods are commonly consumed by Americans and thus would be a feasible target for people to increase their prebiotic consumption.”
Based on the team’s findings, Boyd said a person would need to consume approximately half of a small (4-ounce) onion to get 5 grams of prebiotics.
Wheat-containing items rank lower on the list. Foods with little or no prebiotic content include dairy products, eggs, oils, and meats.
The researchers hope the study will provide a basis to help other scientists assess the health impacts of prebiotics and inform future dietary guidelines. They noted that more research is needed to understand how cooking impacts prebiotic content and to better assess foods that contain multiple ingredients.
Boyd will present this research at noon EDT on Saturday, July 22, during the Food Science and Nutrition Poster Session in the Hynes Convention Center Hall C (abstract;presentation details).
Please note that abstracts presented at NUTRITION 2023 were evaluated and selected by a committee of experts but have not generally undergone the same peer review process required for publication in a scientific journal. As such, the findings presented should be considered preliminary until a peer-reviewed publication is available.
About NUTRITION 2023
NUTRITION 2023 is the flagship meeting of the American Society for Nutrition and the premier educational event for nutritional professionals around the globe. NUTRITION brings together lab scientists, practicing clinicians, population health researchers, and community intervention investigators to identify solutions to today’s greatest nutrition challenges. Our audience also includes rising leaders in the field – undergraduate, graduate, and medical students. NUTRITION 2023 will be held July 22-25, 2023 in Boston. https://nutrition.org/N23 #Nutrition2023
About the American Society for Nutrition (ASN)
ASN is the preeminent professional organization for nutrition research scientists and clinicians around the world. Founded in 1928, the society brings together the top nutrition researchers, medical practitioners, policy makers and industry leaders to advance our knowledge and application of nutrition. ASN publishes four peer-reviewed journals and provides education and professional development opportunities to advance nutrition research, practice, and education. Since 2018, the American Society of Nutrition has presented NUTRITION, the leading global annual meeting for nutrition professionals. http://www.nutrition.org
Endangered North Atlantic right whales are in 'crisis'; species approaching extinction
Emily DeLetter,
USA TODAY Wed, July 19, 2023
Officials are warning that a North American species of whale is approaching extinction.
North Atlantic right whales are an endangered species in "crisis," according to a fact sheet from the NOAA Fisheries Marine Mammal and Sea Turtle Conservation Division, with fewer than 350 individuals and fewer than 70 reproductively active females remaining.
The species of whale nearly became extinct after centuries of commercial whaling, but slowly increased to almost 500 individuals in 2010 after protections from the Marine Mammal Protection Act of 1972 and the Endangered Species Act of 1973, according to the NOAA Fisheries.
Snow Cone, a 17-year-old North Atlantic right whale. The endangered species is approaching extinction, according to the NOAA.
North Atlantic right whales can be identified by white calluses on their head. They have a broad back without a dorsal fin and a long mouth that begins above the eye, according to the World Wildlife Fund. Often found in coastal waters, they can grow to be between 45-55 feet long and can weigh up to 70 tons.
The population began declining again in 2017, and the NOAA Fisheries declared an Unusual Mortality Event for the species, which the agency defines as a "a stranding that is unexpected; involves a significant die-off of any marine mammal population; and demands immediate response."
The Unusual Mortality Event has documented 114 whales impacted since 2017: 36 have died, 33 have been seriously injured and 45 have been morbidity cases. The 114 deaths are a minimum count, according to the agency, as a majority of deaths and injuries of right whales have likely gone undetected.
The primary causes of the Universal Mortality Event for the whales are entanglements in fishing gear and vessel strikes in both U.S. and Canadian waters.
LA JOLLA, CALIF. – July 18, 2023 –Research from Sanford Burnham Prebys and the Osaka International Cancer Institute has shed new light on the anti-cancer properties of mannose, a sugar that is crucial to many physiological processes in humans and is also known to inhibit the growth of cancer cells. The findings, published in the journal eLife, suggest that mannose could be a helpful secondary treatment for cancer.
“This sugar could give cancer an extra punch alongside other treatments,” says study co-author Hudson Freeze, Ph.D., director of the Human Genetics Program at Sanford Burnham Prebys. “And because mannose is found throughout the body naturally, it could improve cancer treatment without any undesirable side effects.”
Mannose is a sugar that the body adds to proteins to stabilize their structure and help them interact with other molecules. This process, called glycosylation, is essential for life; and malfunctions in glycosylation are associated with rare, but often life-threatening, human diseases.
“Until now, the most promising therapeutic use for mannose was to treat congenital disorders of glycosylation, diseases that can cause a wide range of severe symptoms throughout the body,” says Freeze. “But we believe that there may be ways to leverage mannose against cancer and other diseases as well.”
Mannose has already been shown to inhibit the growth of several types of cancer in the lab, but scientists don’t fully understand why this happens. To learn more, the research team turned their attention to an unusual property of mannose observed in an unlikely subject: honeybees.
“It’s been known for more than a century that mannose is lethal to honeybees because they can’t process it like humans do—it’s known as ‘honeybee syndrome,’” says Freeze. “We wanted to see if there is any relationship between honeybee syndrome and the anti-cancer properties of mannose, which could lead to an entirely new approach to combat cancer.”
Using genetically engineered human cancer cells from fibrosarcoma—a rare cancer that affects connective tissue—the research team re-created honeybee syndrome and discovered that without the enzyme needed to metabolize mannose, cells replicate slowly and are significantly more vulnerable to chemotherapy.
“We found that triggering honeybee syndrome in these cancer cells made them unable to synthesize the building blocks of DNA and replicate normally,” says Freeze. “This helps explain the anti-cancer effects of mannose that have we’ve observed in the lab.”
While leveraging honeybee syndrome could be a promising supplemental cancer treatment, the researchers caution that because the effect is dependent on vital metabolic processes, more research is needed to determine which types of cancer would be most vulnerable to mannose.
“If we can find cancers that have a low activity of the enzyme that processes mannose, treating them with mannose could give just enough of a nudge to make chemotherapy more effective,” says Freeze. “Many people assume that you always discover treatments in response to the disease, but sometimes you find biology that could be useful for treatment and then have to find the disease to match it.”
In the meantime, the study speaks to the broader potential of glycosylating sugars for cancer treatment, which is still an emerging area of research.
“The glycobiology of sugar metabolism within cancer cells is still an unexplored frontier, and it could be an untapped treasure trove of potential treatments just waiting to be discovered,” adds Freeze.
###
Additional authors on the study include Yoichiro Harada, Yu Mizote, Toru Hiratsuka, Yusuke Imagawa, Kento Maeda, Yuki Ohkawa, Shigeki Higashiyama, Hideaki Tahara and Naoyuki Taniguchi, Osaka International Cancer Institute; Takehiro Suzuki and Naoshi Dohmae, RIKEN Center for Sustainable Resource Science; Akiyoshi Hirayama, Satsuki Ikeda and Junko Murai, Keio University; Mikako Nishida and Heiichiro Udono, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences; and Ayaka Ueda and Eiji Miyoshi, Osaka University.
The study was supported by the Takeda Science Foundation, JSPS KAKENHI (JP23K06645), the Rocket Fund, and the National Institutes of Health (R01DK99551).
The study’s DOI is 10.7554/eLife.83870.
About Sanford Burnham Prebys
Sanford Burnham Prebys is an independent biomedical research institute dedicated to understanding human biology and disease and advancing scientific discoveries to profoundly impact human health. For more than 45 years, our research has produced breakthroughs in cancer, neuroscience, immunology and children’s diseases, and is anchored by our NCI-designated Cancer Center and advanced drug discovery capabilities. For more information, visit us at SBPdiscovery.org or on Facebook facebook.com/SBPdiscovery and on Twitter @SBPdiscovery.
IMAGE: FAIRY CIRCLES IN THE NAMIB DESERT.view more
CREDIT: UHH/MIN/JUERGENS
For more than ten years, researchers have been discussing how the numerous circular bare patches in the middle of the African grasslands - the so-called fairy circles - can arise. In their current study "Sand termite herbivory causes Namibia's fairy circles - A response to Getzin", biologist Prof Dr Norbert Jürgens and soil scientist Dr Alexander Gröngröft from Universität Hamburg confirm that termites are the cause of the fairy circles. At the same time, they refute central arguments of the explanation put forward by ecosystem modellers that the circles are caused by self-regulation of the grasses.
As early as 2013, the Hamburg botanist Norbert Jürgens published, that purely subterranean sand termites of the genus Psammotermes cause the bare patches and, by eliminating the plants in the sandy soils, enable long-lasting storage of water after infrequent rainfall. This explanation, published in “Science”, was confirmed in the years that followed by entomologists from southern Africa (Prof Mike Picker, Dr Joh Henschel, Dr Kelly Vlieghe).
Other researchers also investigated the mysterious phenomenon, e.g. at the University of Göttingen using modelling approaches. The researchers published (Getzin et al. 2015, 2022) that the bare patches are caused by self-organisation of the grass plants, which draw water unevenly to themselves with their roots and through extensive diffusion in the sandy soils, thus causing the death of grasses in the bare patches. Furthermore, by measuring soil moisture beneath the fairy circle in 20 cm depth, they found desiccation, which they interpreted as caused fast horizontal sucking of water by the grasses of the surrounding.
Norbert Jürgens and Alexander Gröngröft now refute the central arguments of the modellers from Göttingen in the article published by PPEES: In their study, Jürgens and Gröngröft demonstrated the presence of sand termites on more than 1,700 fairy circles in Namibia, Angola and South Africa. The soil moisture measurements cited by Getzin et. al (2022) as evidence for the self-organisation hypothesis coincide with Jürgens' soil moisture measurements in 2013. However, the interpretations differ: While the modellers measure in the topsoil and interpret its drying out as withdrawal of water by the surrounding grasses, Jürgens showed in 2013 by simultaneous measurement at four different depths of up to 90 cm that the fairy circles in the subsoil store the water for a long time.
"Of even greater significance is that the analysis of my colleague Gröngröft and the measurements of the hydrological properties of the desert sand carried out in the laboratory invalidate the crucial foundations of the assumption of self-regulation," says Jürgens. "The water conductivity of the coarse-grained sand of the fairy circles, in which the termites live, is indeed very high when a lot of water is present during a heavy rain event, which can then quickly seep away in the large pores. However, the situation is completely different when the sand has released the easily movable water into the depths and has dried out to less than about eight percent of the soil volume. Then water is only stored at the points of contact between the sand grains, a continuous film of water is missing and the soil's ability to conduct water drops to very low levels. This means that at the levels of moisture found below fairy circles (≤5% by volume), very little liquid water transport can take place over short distances." The formation of dry sand layers on the soil surface directly above moist subsoil demonstrates this physical phenomenon.
"The horizontal water transports over metres in a few days assumed by the representatives of self-regulation are physically impossible according to current knowledge. The debate about opposing interpretations of a biological phenomenon is thus surprisingly decided by physics, in this case soil physics," says Jürgens. "The soil moisture measurements on the fairy circles and the soil hydraulic properties of the sand found in the laboratory thus rule out the self-regulation hypothesis as an explanation for the fairy circles. The cause for the formation of the fairy circles is thus clear - it is the sand termites that secure a considerable survival advantage through soil moisture storage."
JOURNAL
Perspectives in Plant Ecology Evolution and Systematics
