Culture

Scientists have developed a new theory as to how hearing loss may cause dementia and believe that tackling this sensory impairment early may help to prevent the disease.

Hearing loss has been shown to be linked to dementia in epidemiological studies and may be responsible for a tenth of the 47 million cases worldwide.

Now, published in the journal Neuron, a team at Newcastle University, UK, provide a new theory to explain how a disorder of the ear can lead to Alzheimer's disease - a concept never looked at before.

It is hoped that this new understanding may be a significant step towards advancing research into Alzheimer's disease and how to prevent the illness for future generations.

Newcastle experts considered three key aspects; a common underlying cause for hearing loss and dementia; lack of sound-related input leading to brain shrinking; and cognitive impairment resulting in people having to engage more brain resources to compensate for hearing loss, which then become unavailable for other tasks.

The team propose a new angle which focuses on the memory centres deep in the temporal lobe. Their recent work indicates that this part of the brain, typically associated with long-term memory for places and events, is also involved in short-term storage and manipulation of auditory information.

They consider explanations for how changes in brain activity due to hearing loss might directly promote the presence of abnormal proteins that cause Alzheimer's disease, therefore triggering the disease.

Professor Tim Griffiths, from Newcastle University's Faculty of Medical Sciences, said: "The challenge has been to explain how a disorder of the ear can lead to a degenerative problem in the brain.

"We suggest a new theory based on how we use what is generally considered to be the memory system in the brain when we have difficulty listening in real-world environments."

Work on mechanisms for difficult listening is a central theme for the research group, including members in Newcastle, UCL and Iowa University, that has been supported by a Medical Research Council programme grant.

Dr Will Sedley, from Newcastle University's Faculty of Medical Sciences, said: "This memory system engaged in difficult listening is the most common site for the onset of Alzheimer's disease.

"We propose that altered activity in the memory system caused by hearing loss and the Alzheimer's disease process trigger each other.

"Researchers now need to examine this mechanism in models of the pathological process to test if this new theory is right."

The experts developed the theory of this important link with hearing loss by bringing together findings from a variety of human studies and animal models. Future work will continue to look at this area.

Astronomers have known for two decades that the expansion of the universe is accelerating, but the physics of this expansion remains a mystery. Now, a team of researchers at the University of Hawai'i at Mānoa have made a novel prediction--the dark energy responsible for this accelerating growth comes from a vast sea of compact objects spread throughout the voids between galaxies. This conclusion is part of a new study published in The Astrophysical Journal.

In the mid-1960s, physicists first suggested that stellar collapse should not form true black holes, but should instead form Generic Objects of Dark Energy (GEODEs). Unlike black holes, GEODEs do not 'break' Einstein's equations with singularities. Instead, a spinning layer surrounds a core of dark energy. Viewed from the outside, GEODEs and black holes appear mostly the same, even when the "sounds" of their collisions are measured by gravitational wave observatories.

Because GEODEs mimic black holes, it was assumed they moved through space the same way as black holes. "This becomes a problem if you want to explain the accelerating expansion of the universe," said UH Mānoa Department of Physics and Astronomy research fellow Kevin Croker, lead author of the study. "Even though we proved last year that GEODEs, in principle, could provide the necessary dark energy, you need lots of old and massive GEODEs. If they moved like black holes, staying close to visible matter, galaxies like our own Milky Way would have been disrupted.''

Croker collaborated with UH Mānoa Department of Physics and Astronomy graduate student Jack Runburg, and Duncan Farrah, a faculty member at the UH Institute for Astronomy and the Physics and Astronomy department, to investigate how GEODEs move through space. The researchers found that the spinning layer around each GEODE determines how they move relative to each other. If their outer layers spin slowly, GEODEs clump more rapidly than black holes. This is because GEODEs gain mass from the growth of the universe itself. For GEODEs with layers that spin near the speed of light, however, the gain in mass becomes dominated by a different effect and the GEODEs begin to repel each other. "The dependence on spin was really quite unexpected," said Farrah. "If confirmed by observation, it would be an entirely new class of phenomenon."

The team solved Einstein's equations under the assumption that many of the oldest stars, which were born when the universe was less than 2 percent of its current age, formed GEODEs when they died. As these ancient GEODEs fed on other stars and abundant interstellar gas, they began to spin very rapidly. Once spinning quickly enough, the GEODEs' mutual repulsion caused most of them to 'socially distance' into regions that would eventually become the empty voids between present-day galaxies.

This study supports the position that GEODEs can solve the dark energy problem while remaining in harmony with different observations across vast distances. GEODEs stay away from present-day galaxies, so they do not disrupt delicate star pairs counted within the Milky Way. The number of ancient GEODEs required to solve the dark energy problem is consistent with the number of ancient stars. GEODEs do not disrupt the measured distribution of galaxies in space because they separate away from luminous matter before it forms present-day galaxies. Finally, GEODEs do not directly affect the gentle ripples in the afterglow of the Big Bang, because they are born from dead stars hundreds of millions of years after the release of this cosmic background radiation.

The researchers were cautiously optimistic about their results. "It was thought that, without a direct detection of something different than a Kerr [Black Hole] signature from LIGO-Virgo [gravitational wave observatories], you'd never be able to tell that GEODEs existed," said Farrah. Croker added, "but now that we have a clearer understanding of how Einstein's equations link big and small, we've been able to make contact with data from many communities, and a coherent picture is beginning to form."

According to Runburg, whose primary research interest is unrelated to GEODEs, "the most exciting consequence, for me, is that previously disconnected communities of researchers now have common ground. When different communities work together, the whole always becomes something greater than the sum of the parts."

It is a well-known problem: too rarely do nature conservation initiatives, recommendations or strategies announced by politicians lead to people really changing their everyday behaviour. A German-Israeli research team led by the Helmholtz Centre for Environmental Research (UFZ) and the German Centre for Integrative Biodiversity Research (iDiv) has investigated the reasons for this. According to the team, the measures proposed by politicians do not sufficiently exploit the range of possible behavioural interventions and too rarely specify the actual target groups, they write in the journal Conservation Biology.

The protection of pollinating insects is a major issue in international nature conservation policy. Stirred up by scientific findings on high population losses of insect groups such as bees or butterflies, which, for example, affect pollination services in agriculture, Europe is putting insect protection at the forefront of environmental policy. Many governments in Europe have presented national strategies to ensure that pollinators are maintained. A team of researchers from UFZ, iDiv and Technion - Israel Institute of Technology analysed the available eight national strategy papers to protect pollinators in terms of behavioural change interventions. The result: "Nature conservation policies to preserve pollinators are often too ineffective in this respect and change little in people's behaviour," says first author and environmental psychologist Dr. Melissa Marselle, who is conducting research at the UFZ and iDiv on the impact of biodiversity on human health.

The scientists coded around 610 behavioural measures in the strategy papers. Using the "Behaviour Change Wheel" theory, which originates from health psychology and integrates 19 different behavioural models, the scientists categorized the behavioural measures for pollinator conservation into the nine different types of interventions - i.e. measures that could change people's behaviour. According to this, most of the 790 or so behavioral measures for pollinator conservation (23 percent) can be assigned to the behaviour change interventions of education and awareness raising, followed by structural measures such as planting hedges, sowing flower strips in fields or creating green spaces in the city (19 percent). Only around four percent of the behavioural measures for pollinator conservation can be summarized under the intervention of modeling, for example, peer-to-peer learning or the use of best-practice examples from farmers who work in exemplary fashion. Other little-mentioned behavioural interventions for pollinator conservation were incentive systems for farmers or municipalities (three percent) and statutory regulations (two percent). Interventions that create a financial cost to discourage a certain behaviour, such as additional taxes on the use of pesticides, did not appear in any of the policy papers for pollinator conservation.

"This shows that national biodiversity strategies focus primarily on educational and structural measures and neglect other effective instruments," says Melissa Marselle. "Educational measures to impart knowledge and to create understanding are important. But relying on education alone is not very effective if you really want to change environmental behaviour. It would be more effective to link it to a wider range of other measures." For example, clearly identifying supply chains and producer principles on labels can encourage many people to buy an organic or pollinator-friendly products - even at a higher price. Stronger financial incentives for farmers who operate sustainably would also be effective, and the certification of sustainable buildings could be linked to the use of pollinator-friendly plants as flower beds. Taxes and additional costs for consumers also ensure rapid changes in behaviour: In the UK, for example, a compulsory levy on the purchase of plastic bags has led to a decline in their use.

A further shortcoming of the strategy papers was identified as the fact that in 41 percent of the behavioural measures for pollinator conservation the target groups whose behaviour needs to change were not named and specified. The objectives are often very well described, but mostly revolve around the question of how certain actions change the environment. However, it is often not defined in more detail to whom the actions are directed and who should implement them: the public, farmers or local authorities? It could be more effective to first consider what the different actors can do, with the help of behavioural researchers, and then, building on that, to consider measures to achieve certain goals.

There are currently several important opportunities to write nature conservation strategies better. For example, the EU Biodiversity Strategy 2030, which the EU Commission adopted in May 2020, needs to be translated into national policies. In addition, at the next conference of the Convention of Biological Diversity (CBD) next year in China, global biodiversity targets for the following years will be negotiated. "Against this background, it is crucial to understand how policies need to be formulated in order to achieve effective implementation of international nature conservation policies", says Prof. Aletta Bonn, who heads the Department of Ecosystem Services at UFZ and iDiv with a research focus on interaction of people and nature.

CINCINNATI - Scientists studying neuronal energy metabolism found evidence that the loss of an important energy regulator called AMPK in neural stem cells or glial cells called astrocytes causes neuronal death in laboratory rodents. They also discovered that AMPK loss in neural stem cells or neurons causes spontaneous brain seizures in the animals.

Publishing their findings in Cell Reports, the multi-institutional research team--led by Cincinnati Children's cancer biologist Biplab Dasgupta, PhD--said deleting AMPK from astrocyte brain cells led to severe disruption of glucose and lactate metabolism in neurons. The clue came from the first ever magnetic resonance spectroscopy studies in brain-specific AMPK deletion mice done at the University of Minnesota (UM).

The collaborative study, which included Raghu Rao, MD, and Ivan Tkac, PhD, at UM, revealed that AMPK deleted mice have about 40 percent lower lactate levels, a key result that was verified in cultured astrocytes.

The findings that AMPK deleted neurons demonstrate spontaneous seizures and are vulnerable to low dose seizure-inducing agents came from the neurology laboratory of Christina Gross, PhD, of Cincinnati Children's, and appear to suggest that the popular antidiabetic drug metformin (that also activates AMPK) may mitigate epileptic seizures. Metformin is currently being tested preclinically in laboratory rodents, according to Dasgupta, a principal investigator in the Cancer and Blood Diseases Institute.

"Very little is known about how astrocytes regulate glycolysis to generate lactate and supply it to neurons to support their metabolism and proper functioning," Dasgupta said. "We show for the first time that AMP kinase (AMPK) is the bottom line of the mechanism that controls astrocytic glycolysis and lactate production in the brain. And we show that interfering with this process does little harm to astrocytes but damages neurons."
Neuronal metabolism is critical to every aspect of our lives and functioning. The question of whether glial cells like astrocytes are necessary for proper neuron metabolism and survival has been debated in the scientific field for decades.

Researchers in the current study set out to make progress toward settling that debate and they used a long list of experimental procedures to come up with some new answers. Importantly, the results obtained in mouse brains from the Dasgupta lab were recapitulated in the brains of the fruit fly Drosophila where using six different models of AMPK deletion.

Study co-author Dr. Stefanie Schirmeier at the University of Münster in Germany found that AMPK deletion in the fly glia causes neuronal death and reduces lifespan of the mutant flies. This and other results, including conservation of these functions in human astrocytes, make it possible that AMPK-controlled lactate metabolism provides life support for neurons in people, according to the researchers.

Bethesda, MD (September 1, 2020) -- The American Gastroenterological Association (AGA) published new clinical guidelines outlining an evidence-based approach for the initial gastrointestinal evaluation of chronic iron deficiency anemia in asymptomatic patients. Iron deficiency anemia is extremely common worldwide, and a gastrointestinal cause should be considered in all patients without an obvious cause for their anemia.

"Iron deficiency anemia is encountered commonly in clinical practice, yet there is significant practice variability among physicians evaluating these patients," said Cynthia W. Ko, lead guideline author from University of Washington School of Medicine, Seattle. "We're pleased to introduce this guideline, which will walk gastroenterologists through the recommended management of these patients to ensure we find and address early any underlying risk of serious diseases and provide the best possible outcomes for our patients."

Key guideline recommendations:

1. AGA strongly recommends that clinicians carefully document the presence of each iron deficiency and anemia prior to endoscopic evaluation.

2. AGA strongly recommends that gastroenterologists perform bidirectional endoscopy on asymptomatic men and postmenopausal women with iron deficiency anemia. AGA conditionally offers the same recommendation for premenopausal women and encourages shared decision making with these patients. If a patient has GI symptoms, diagnostic evaluation should be tailored accordingly. EGD/colonoscopy (or colonoscopy/EGD) should be performed at the same sitting.

3. Perform non-invasive testing for Helicobacter pylori and celiac disease in asymptomatic patients with iron deficiency anemia prior to bidirectional endoscopy. If positive, begin treatment. AGA recommends against performing routine gastric or duodenal biopsies if non-invasive tests are negative.

4. In uncomplicated asymptomatic patients with iron deficiency anemia and in whom no source of potential blood loss is identified after initial evaluation with bidirectional endoscopy and non-invasive testing, a trial of iron supplementation is recommended before routine evaluation of the small bowel with video capsule endoscopy. 

Biological sex influences the effect of amyloid beta on alterations to tau protein characteristic to Alzheimer's disease, suggesting a role for estradiol in preventing the disease in women, report scientists in the Journal of Alzheimer's Disease

Amsterdam, September 1, 2020-Alzheimer's disease (AD) is the most common neurodegenerative disease and the leading cause of dementia. It affects more women than men. A new study published in the Journal of Alzheimer's Disease indicates that factors such as age, reproductive stage, hormone levels, and the interplay with other risk factors should be considered in women and proposes a role for early menopausal estrogen replacement to protect against the development of AD.

"The risk of developing AD as well as its progression and severity are known to be very different in men and women," explained co-lead investigator Elena Tamagno, PhD, Department of Neuroscience and Neuroscience Institute of Cavalieri Ottolenghi Foundation (NICO), University of Torino, Torino, Italy. "Recent epidemiological studies showed that two thirds of AD patients are women, and this fact cannot be attributed only to their higher life expectancy. The loss of estradiol might be one of the factors leading to declining cognitive function in women."

Hallmarks of AD are the accumulation of amyloid beta peptides in amyloid plaques, and the aggregation of modified tau protein to form neurofibrillary tangles. Tau proteins are abundant in nerve cells and perform the function of stabilizing microtubules, and are pathologically altered in AD. To examine the hypothesis that biological sex influences the effect of amyloid beta 42 (AB42) peptides on these changes to tau protein, investigators gave intraventricular injections of nanomolecular concentrations of AB42 to transgenic mice expressing the wild-type human tau (hTau). In a previous study the investigators had noted that female mice did not show the alterations of tau protein characteristic of AD. In the current study they demonstrated that AB42 caused the pathological form of tau in ovariectomized female mice, but not in control females, and that estrogen replacement reversed this effect through an antioxidant activity and a decrease of tau phosphorylation.

"Our study indicates that factors such as age, reproductive stage, hormone levels, and the interplay with other risk factors should be considered in women, in order to identify the best appropriate treatment in prevention of cognitive impairment," commented co-lead investigator Massimo Tabaton, MD, Unit of Geriatric Medicine, Department of Internal Medicine and Medical Specialties (DIMI), University of Genova, Genova, Italy. "Our results suggest that an early postmenopausal estrogen replacement may be protective against AD."

"Linking estrogen deficiency to the tau changes of AD provides the missing mechanistic link to the greater risk of AD in women and significantly suggests therapeutic avenues to reduce AD," added George Perry, PhD, Editor-in-Chief of the Journal of Alzheimer's Disease and Semmes Foundation Distinguished University Chair in Neurobiology at The University of Texas at San Antonio.

AD is a major social and health problem. In the United States, approximately 5.5 million people are affected, and the number is growing as a result of the increase in life expectancy. The prevalence of dementia worldwide is estimated at 24 million people, which is expected to double by 2050. AD is characterized by progressive cognitive decline usually beginning with impairment in the ability to form recent memories, but inevitably affecting all intellectual functions and leading to complete dependence for basic functions of daily life and premature death. Women are more likely to develop the disease, independent of their longer life expectancy: one in six women over 65 develops AD, compared with one in 11 men.

Even though recognised in the Mediterranean Sea, the Macropodia czernjawskii spider crab was ignored by scientists (even by its namesake Vladimir Czernyavsky) in the regional faunal accounts of the Black Sea for more than a century. At the same time, although other species of the genus have been listed as Black sea fauna, those listings are mostly wrong and occurred either due to historical circumstances or misidentifications.

Now, scientists re-describe this, most likely, only species of the genus occurring in the Black Sea in the open-access journal Zoosystematics and Evolution.

The spider crab genus Macropodia was discovered in 1814 and currently includes 18 species, mostly occurring in the Atlantic and the Mediterranean. The marine fauna of the Black Sea is predominantly of Mediterranean origin and Macropodia czernjawskii was firstly discovered in the Black Sea in 1880, but afterwards, its presence there was largely ignored by the scientists.

After the revision of available type specimens from all available collections in the Russian museums and the Senckenberg Museum in Frankfurt-on-Main, as well as newly collected material in the Black Sea and the North-East Atlantic, a research team of scientists, led by Dr Vassily Spiridonov from Shirshov Institute of Oceanology of Russian Academy of Sciences, re-described Macropodia czernjawskii and provided the new data on its records and updated its ecological characteristics.

"The analysis of the molecular genetic barcode (COI) of the available material of Macropodia species indicated that M. czernjawskii is a very distinct species while M. parva should be synonimised with M. rostrata, and M. longipes is a synonym of M. tenuirostris", states Dr Spiridonov sharing the details of the genus analysis.

All Macropodia species have epibiosis and M. czernjawskii is no exception: almost all examined crabs in 2008-2018 collections had significant epibiosis. It normally consists of algae and cyanobacteria and, particularly, a non-indigenous species of red alga Bonnemaisonia hamifera, officially reported in 2015 at the Caucasian coast of the Black Sea, was found in the epibiosis of M. czernjawskii four years earlier.

"It improves our understanding of its invasion history. Museum and monitoring collections of species with abundant epibiosis (in particular inachid crabs) can be used as an additional tool to record and monitor introduction and establishments of sessile non-indigenous species," suggests Dr Spiridonov.

ADELPHI, Md. -- A new, miniature, low-frequency antenna with enhanced bandwidth will enable robust networking among compact, mobile robots in complex environments.

In a collaborative effort between the U.S. Army Combat Capabilities Development Command's Army Research Laboratory and the University of Michigan, researchers developed a novel design approach that improves upon limitations of conventional antennas operating at low frequencies--demonstrating smaller antennas that maintain performance.

Impedance matching is a key aspect of antenna design, ensuring that the radio transmits power through the antenna with minimal reflections while in transmit mode--and that when the antenna is in receive mode, it captures power to efficiently couple to the radio over all frequencies within the operational bandwidth.

"Conventional impedance matching techniques with passive components--such as resistors, inductors and capacitors--have a fundamental limit, known as the Chu-Wheeler limit, which defines a bound for the maximum achievable bandwidth-efficiency product for a given antenna size," said Army researcher Dr. Fikadu Dagefu. "In general, low-frequency antennas are physically large, or their miniaturized counterparts have very limited bandwidth and efficiency, resulting in higher power requirement."

With those challenges in mind, the researchers developed a novel approach that improves bandwidth and efficiency without increasing size or changing the topology of the antenna.

"The proposed impedance matching approach applies a modular active circuit to a highly miniaturized, efficient, lightweight antenna--overcoming the aforementioned Chu-Wheeler performance limit," said Army postdoctoral researcher Dr. Jihun Choi. "This miniature, actively matched antenna enables the integration of power-efficient, low-frequency radio systems on compact mobile agents such as unmanned ground and aerial vehicles."

The researchers said this approach could create new opportunities for networking in the Army.

The ability to integrate low-frequency radio systems with low size, weight, and power--or SWAP--opens the door for the exploitation of this underutilized and underexplored frequency band as part of the heterogeneous autonomous networking paradigm. In this paradigm, agents equipped with complementary communications modalities must adapt their approaches based on challenges in the environment for that specific mission. Specifically, the lower frequencies are suitable for reliable communications in complex propagation environments and terrain due to their improved penetration and reduced multipath.

"We integrated the developed antenna on small, unmanned ground vehicles and demonstrated reliable, real-time digital video streaming between UGVs, which has not been done before with such compact low-frequency radio systems," Dagefu said. "By exploiting this technology, the robotic agents could coordinate and form teams, enabling unique capabilities such as distributed on-demand beamforming for directional and secure battlefield networking."

With more than 80 percent of the world's population expected to live in dense urban environments by 2050, innovative Army networking capabilities are necessary to create and maintain transformational overmatch, the researchers said. Lack of fixed infrastructure coupled with the increasing need for a competitive advantage over near-peer adversaries imposes further challenges on Army networks, a top modernization priority for multi-domain operations.

While previous experimental studies demonstrated bandwidth enhancement with active matching applied to a small non-resonant antenna (e.g., a short metallic wire), no previous work simultaneously ensures bandwidth and radiation efficiency enhancement compared to small, resonant antennas with performance near the Chu-Wheeler limit.

The Army-led active matching design approach addresses these key challenges stemming from the trade-off among bandwidth, efficiency and stability. The researchers built a 15-centimeter prototype (2 percent of the operating wavelength) and demonstrated that the new design achieves more than threefold bandwidth enhancement compared to the same antenna without applying active matching, while also improving the transmission efficiency 10 times compared to the state-of-the-art actively matched antennas with the same size.

"In the design, a highly accurate model captures sharp impedance variation of the highly miniaturized resonant antenna" Choi said. "Based on the model, we develop an active matching circuit that enhances bandwidth and efficiency simultaneously while ensuring the circuit is fully stable."

The team published their research, A Miniature Actively Matched Antenna for Power-Efficient and Bandwidth-Enhanced Operation at Low VHF, authored by Drs. Jihun Choi, Fikadu Dagefu, Brian Sadler, and Prof. Kamal Sarabandi, in the peer-reviewed journal Institute of Electrical and Electronics Engineers Transactions on Antennas and Propagation.

"This technology is ripe for future development and transition to our various partners within the Army," Dagefu said. "We are optimistic that with the integration of aspects of our heterogeneous networking research, this technology will further develop and will be integrated into future Army communications systems."

Misfiring brain cells that control key parts of the mouth and tongue may be creating swallowing difficulties in children with neurodevelopmental disorders, according to neuroscientists with Virginia Tech and George Washington University.

In research using a mouse model of a genetic childhood disorder known as DiGeorge syndrome, scientists found brain cells called motor neurons that directly control the tongue muscles were firing spontaneously, out of sync with the mechanisms that should control their activity.

Finding ways to calm the motor neurons responsible for moving the tongue could lead to improved function in very young children who have difficulty swallowing, eating, or making sounds, but the scientists said more research is needed before developing therapies.

"We are continuing to make the case that activity of the motor neurons that command the movement of key parts of the mouth, tongue, and pharynx are disrupted by the same mechanisms causing genetic neurodevelopmental disorders," said Anthony-Samuel LaMantia, senior co-author of the study, a developmental neurobiologist, and a professor at the Fralin Biomedical Research Institute at VTC. "Our goal is to learn about the causes of these symptoms to help children as early in life as possible."

The study was published online in advance in eNeuro, an open-access journal of the Society for Neuroscience.

Problems ingesting, chewing, or swallowing food occur in up to 80 percent of children with developmental disorders and can lead to food aspiration, choking, or life-threatening respiratory infections.

Suckling, feeding, and swallowing difficulties -- known as pediatric dysphagia -- are among the most serious and frequent complications in infants. They are common in DiGeorge syndrome, which is a genetic disease caused when a small part of chromosome 22 is missing. The syndrome carries a high risk for autism spectrum disorder and schizophrenia, as well as heart, face, and limb malformations.

In the study, associate research professor Xin Wang and co-senior author David Mendelowitz, vice chair and professor of pharmacology and physiology, both with the George Washington University School of Medicine and Health Sciences, traced the motor neurons in mouse models DiGeorge syndrome from their target muscles, labeled each class of motor neuron, and recorded their electrical properties.

The motor neurons responsible for the forward and backward movement of the tongue in the DiGeorge syndrome models spontaneously fired compared with motor neurons of normal mice, and the excitatory impulses were not balanced by inhibitory responses.

As a result, the increased excitability of motor neurons affected compression and movement of the tongue muscles, which would threaten both food intake efficiency and airway safety in infants and toddlers.

New insight on how an enzyme ensures the correct growth of pollen tubes in flowering plants has been published today in the open-access journal eLife.

The study reveals an unexpected role of KATANIN in moderating the mechanical properties of the papilla cell wall in Arabidopsis thaliana (A. thaliana), thereby preventing disordered pollen tube growth and allowing the tube to find its correct path to the underlying female plant tissues. These findings suggest that KATANIN has likely played a major role in the success of flowering plants on earth more widely.

Seeds are produced in flowering plants when male and female germ cells called gametes fuse together. Male gametes are contained in the pollen grain while female gametes are found in the ovules, which are embedded in a female reproductive organ called the pistil. For successful seed production to happen, pollen grains need to meet with the surface of the pistil, which is composed of a layer of elongated cells called papillae. When a pollen grain lands on a papilla, it rehydrates and then produces a tube that will carry the male gametes toward the ovules.

Pollen tubes grow first within the papilla cell wall, exerting a physical pressure on the cell. After crossing the papilla layer, they then grow in the intercellular space of underlying tissues. The pistil then produces compounds that guide the pollen tube to the ovules where it reaches the female gametes. But how the tube orients itself when it emerges from the pollen at the papilla surface remains unknown.

"It is striking that, whatever the position of the flower and hence the pistil on the stem, the pollen tube grows to the base of the papilla in the direction of the ovules. We wanted to explore the mechanisms that allow for this proper orientation of pollen tubes on the papilla cells," says lead author Lucie Riglet, who was a PhD student in senior author Thierry Gaude's lab at the Laboratory of Plant Reproduction and Development, ENS Lyon, France, at the time the study was carried out, and is now a postdoctoral researcher at the Sainsbury Laboratory, University of Cambridge, UK.

Mechanical forces are known to play a major role in plant cell shape by controlling the orientation of cortical microtubules, which in turn mediate the deposition of cellulose microfibrils. For their study, Riglet and her team combined imaging, genetic and chemical approaches to show that the enzyme KATANIN, which cuts microtubules, also acts on cellulose microfibril orientation and confers mechanical properties to the papilla cell wall that allow for correct pollen tube orientation.

"By forcing the pollen tubes to take the right direction from their early places in the papilla, KATANIN has likely played a major role in the success of flowering plants on earth by promoting fertilisation," explains senior author Thierry Gaude, Group Leader at the Laboratory of Plant Reproduction and Development, ENS Lyon. "As KATANIN is found in most organisms, including humans, it is possible that the enzyme plays a role in regulating mechanical properties in other processes - but this is a fascinating question that remains to be explored."

Population bottlenecks contribute to the accumulation of several harmful mutations that cause age-related illnesses in killifish - a finding that may help answer a key question about aging.

The study, published today in eLife, reveals why killifish accumulate harmful mutations that cause age-related conditions such as cancer or neurodegenerative diseases that shorten lifespan. This may help scientists better understand how lifespan evolves among populations and may lead to new insights on human aging.

The very short lives of turquoise killifish - between three and nine months - make them an ideal model for studying aging. Killifish live in temporary ponds in Africa that dry up for part of the year, meaning they must hatch, mature and reproduce before this happens. Their eggs survive the dry periods in a hibernation-like state and hatch when rains fill the pond again, starting a new generation.

"Different wild turquoise killifish populations have varying lifespans, and we wanted to explore the reasons behind this," explains lead author David Willemsen, Postdoctoral Research Fellow at the Max Planck Institute for Biology of Ageing, Cologne, Germany.

For their study, Willemsen and senior author Dario Riccardo Valenzano carried out field work in savanna pools in Zimbabwe to catch and collect genome samples from the killifish for sequencing and analysing in the lab. The team then compared the genomes of killifish living in the driest environments, which have the shortest lives, with the genomes of killifish from wetter environments, which live for months longer.

The short-lived killifish have very small, often isolated populations, leading to so-called population bottlenecks which, the team found, result in harmful mutations accumulating in their populations. By contrast, the longer-lived killifish have larger populations and new fish with new genetic material frequently join their populations. Over time, these larger populations make it more efficient for natural selection to remove harmful mutations.

"Limited population sizes caused by habitat fragmentation and repeated population bottlenecks increase the chance for harmful mutations to accumulate in the population," Willemsen says. "Our work may help answer a key question about aging by suggesting that population dynamics, rather than evolutionary selection for or against specific genes, contribute to this accumulation of harmful mutations that result in aging and shorter life."

The results support a model where, given the brief rainy seasons, killifish are under strong selective constraints to survive in the absence of water as dormant embryos and to rapidly reach sexual maturation and reproduce before the water completely evaporates. However, the team believes that killifish are not selected to be short-lived. Instead, harmful mutations that affect late-life survival and reproduction (together causing aging in the killifish) accumulate over generations without being constrained by selection.

"Harmful mutations passively accumulate in killifish populations, and this is even more prominent in smaller populations which happen to live in drier environments," says senior author Dario Riccardo Valenzano, Group Leader at the Max Planck Institute for Biology and Ageing, and Principle Investigator at CECAD, the Cluster of Excellence for Ageing Research at the University of Cologne, Germany. "Our findings highlight the role of demographic constraints in shaping lifespan within species and could potentially be expanded to provide new insights on aging within other animal and human populations."

COLUMBIA, SC - September 1, 2020 - The University of South Carolina (UofSC) College of Engineering and Computing will transform the manufacturing and simulation processes used in aircraft production through a $5.7 million NASA grant. The research team's atom to airframe to spaceframe approach will make urban air mobility possible by dramatically increasing the production rate of aircraft.

Ranging from drone delivery services to air metro services to air taxis, urban air mobility refers to in-air transportation within urban areas. It is expected to be a commercially viable market by 2030. However, this will require aircraft to be built in much higher quantities and frequencies than currently being produced.

Today, high-selling aircraft like the Boeing MAXX and the Airbus A321 can be produced at a rate of 60 to 70 aircraft a month, or two to three aircraft a day. Michel van Tooren, the initiator of the NASA proposal and the former director of UofSC's SmartState Center for Multifunctional Materials and Structures, predicts that urban air transport will ultimately require 100 aircraft to be produced a day.

"How do you do that?" van Tooren says. "And if you do 100 aircraft a day and it's maybe 30 blades on an aircraft, then that's 3,000 blades a day. There's no technology available at the moment that creates such an enormous number of aircraft-quality products, and that's the big challenge."

The South Carolina team - in partnership with Boise State University, The University of Southern Mississippi, Benedict College and multiple industry partners - will work to make these production demands possible through a four-year NASA University Leadership Initiative (ULI) grant. South Carolina's research team consists of Darun Barazanchy, Wout De Backer, Jaspreet Pandher and Paul Ziehl, who coordinates and serves as the principal investigator for the project.

"In an impressively short period, the UofSC McNair Aerospace Center has become a household name in the aerospace composites world, especially in the area of thermoplastics and fastener-free joining, as well as robotics, digital commissioning, combustion and predictive maintenance," says Hossein Haj-Hariri, dean of the College of Engineering and Computing. "Receiving one of the coveted NASA ULIs is testimony to the excellence of the center, which continues to pursue and receive similarly competitive and prestigious funding in all its areas, and educates, trains and produces graduates that are at the forefront of their respective disciplines, and highly sought as a result."

Boise State and Southern Mississippi will begin the research using experimental and simulation techniques to make the thermoplastic tape that aircraft are built from stronger and more durable. This tape will then be passed to South Carolina's team, which will use advanced manufacturing processes such as automated fiber placement and automated tape layup to build aircraft parts at a higher production rate. The UofSC team will then use thermoplastic welding, instead of nuts and bolts, to fusion bond the parts together.

"It's a new level of simulation and it's a new way of manufacturing," van Tooren says. "Through it, we can transform aerospace manufacturing and open the door to large-scale urban air mobility sooner than we ever imagined."

The University Leadership Initiative was created by the NASA Aeronautics Research Mission Directorate (ARMD). This $32.8 million ULI has five team leads, including South Carolina, North Carolina Agricultural and Technical State University, Oklahoma State University, Stanford University and the University of Delaware. The ULI will allow these universities to build their own teams and formulate their own research paths in hopes that their findings support the NASA ARMD portfolio and the larger U.S. aviation community.

ITHACA, N.Y. - A new study in mice helps explain why gut microbiomes of breastfed infants can differ greatly from those of formula-fed infants.

The study, "Dietary Sphinganine Is Selectively Assimilated by Members of the Mammalian Gut Microbiome," was published in July in the Journal of Lipid Research.

Sphinganine from milk
Johnson Lab/Provided
A new technique allows researchers to track specific nutrients as they are taken up by gut microbes in a mouse's digestive tract. The image shows certain microbes (red) taking in a nutrient common in human milk called sphinganine; blue microbes have not taken it in.

The paper describes an innovative technique developed at Cornell to track the fate of metabolites - nutrients formed in or necessary for metabolism - through a mouse's digestive tract and identify how they interact with specific gut microbes.

"We think the methods are expandable to many different microbiome systems," said senior author Elizabeth Johnson, assistant professor of nutritional sciences in the College of Agriculture and Life Sciences. She noted that researchers investigating effects of a high-fat vs. low-fat diet, or a keto diet, might use the technique to track metabolites.

The methodology could reveal how specific metabolites promote specific bacteria. This could allow nutritionists to prescribe that patients eat foods containing specific metabolites to intentionally change the composition of their microbiomes, Johnson said.

Human milk and many other foods contain a class of lipid metabolites called sphingolipids. Previous research suggested that these metabolites help shape an infant's microbiome, but it was not known if they actually interact with the microbiome.

The study identified two types of gut microbes, Bacteroides and Bifidobacterium, that use sphingolipids for their own metabolism.

While very little is known about the specific roles of gut microbes in human health, Bacteroides have been implicated in both beneficial and not-so-beneficial effects, depending on context. They are generally associated with microbiomes of healthy breastfed infants. Bifidobacterium, shown for the first time in this study to process dietary sphingolipids, are considered the quintessential beneficial bacteria, comprising up to 95% of breastfed infants microbiome.

They're also a highly popular over-the-counter probiotic.

"Our lab is very interested in how the diet interacts with the microbiome in order to really understand how you can best modulate it to have positive effects on health," Johnson said. "In this study, we were able to see that yes, these dietary lipids that are a big part of [breastfed] infants diets, are interacting quite robustly with the gut microbiome."

Sphingolipids originate from three main sources: diet; bacteria that can produce them; and most host tissues.

Johnson, along with first author Min-Ting Lee, a doctoral student, and Henry Le, a postdoctoral researcher, both in Johnson's lab, created a technique to specifically track dietary sphingolipids as they passed through the mouse gut.

"We custom synthesized the sphingolipid we added to the diet," Johnson said. "It is almost identical to ones derived from breast milk but with a small chemical tag so we could trace the location of the sphingolipid once it was ingested by the mice."

Lee then used a fluorescent label that attached to cells or microbes that absorbed the tagged lipid, such that any bacteria that had taken up sphingolipids lit up red. Microbes from the mice's microbiomes were then isolated and analyzed. Populations with red microbes were separated from the others, and these were then genetically sequenced to identify the species of bacteria.

With further investigation, Le was able to identify the metabolites that Bacteroides and Bifidobacterium produce when exposed to dietary sphingolipids. Further investigations are underway to determine whether these microbially-produced metabolites are beneficial for infant health.

NASA-NOAA's Suomi NPP satellite provided a nighttime view of the Atlantic Ocean hurricane season's latest tropical cyclone off the coast of North Carolina. Ocean swells from the depression are affecting coastal North Carolina today, Sept. 1.

Tropical Depression 15 formed by 5 p.m. EDT off the coast of North Carolina and showed organized convection (rising air that forms the thunderstorms that make up a tropical cyclone). The storm has been battling vertical wind shear since its formation, which has kept it from intensifying into a tropical storm.

NASA's Night-Time View

The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided a nighttime image of 15 during the early morning hours of Sept 1 when it flew over the northwestern Atlantic Ocean. Infrared data showed the most powerful thunderstorms east of center where cloud top temperatures were as cold as or colder than minus 70 degrees Fahrenheit. Deep convection remains displaced to the east and southeast of the depression's low-level center due to increasing west-northwesterly wind shear.

The image was created using the NASA Worldview application at NASA's Goddard Space Flight Center, Greenbelt, Md.

TD15's Status

At 11 a.m. EDT (1500 UTC), NOAA's National Hurricane Center (NHC) reported the center of Tropical Depression 15 (TD 15) was located near latitude 34.7 degrees north and longitude 73.1 degrees west. TD 15 is centered about 140 miles (225 km) east-southeast of Cape Hatteras, North Carolina. The depression is moving toward the east-northeast near 14 mph (22 kph). This general motion is forecast today, followed by a turn toward the east by Thursday. On the forecast track, the center of the depression will continue to move away from the North Carolina coast today.

Maximum sustained winds remain near 35 mph (55 kph) with higher gusts. The depression could become a tropical storm later today or tonight. Gradual weakening is anticipated by late Wednesday. The system is forecast to become a remnant low on Thursday.

TD15's Effects Along the U.S. Coast

Although the depression is off the coast of North Carolina it is generating ocean swells that are affecting the U.S. coast. NHC said, "Swells generated by the depression will continue to affect portions of the Outer Banks of North Carolina through this evening, causing life-threatening surf and rip current conditions." There are no other watches or warnings in effect and the storm is forecast to move away from the coast.

About NASA's EOSDIS Worldview

NASA's Earth Observing System Data and Information System (EOSDIS) Worldview application provides the capability to interactively browse over 700 global, full-resolution satellite imagery layers and then download the underlying data. Many of the available imagery layers are updated within three hours of observation, essentially showing the entire Earth as it looks "right now."

NASA Researches Earth from Space

For more than five decades, NASA has used the vantage point of space to understand and explore our home planet, improve lives and safeguard our future. NASA brings together technology, science, and unique global Earth observations to provide societal benefits and strengthen our nation. Advancing knowledge of our home planet contributes directly to America's leadership in space and scientific exploration.

Online crowdfunding is a multibillion dollar industry, but crafting a compelling pitch that stands out among thousands of projects and lands investors is challenging. This is especially true for small-scale independent restaurant concepts where, due to intense industry competition, risk is high. Kickstarter's food category can have about 30,000 active pitches at any given time, but only about 25% achieve their fundraising goals. In other words, three out of four come up short and fail.

In text analysis of 500 crowdfunding restaurant campaigns on Kickstarter, one of the most popular crowdfunding platforms, researchers at the Conrad N. Hilton College of Hotel and Restaurant Management at the University of Houston identified linguistic styles that could tip the scales for restaurateurs seeking financial backing online.

Project descriptions that are concrete in style and deliver stories with fewer usage of first person pronouns, such as "I" and "my," are more likely to succeed, according to the findings published in the International Journal of Contemporary Hospitality Management.

Lead study author Yoon Koh, associate professor at UH's Hilton College, said concrete words allow faster processing and effectively reduces uncertainty about and strengthens confidence in anticipated business performance. According to previous research in the field of linguistics, three cues to concreteness are use of articles ("a," "an" and "the"), prepositions ("at," "since" and "for") and quantifiers ("few," "many" and "most").

"Concrete language uses specifics so investors can actually picture the idea and what this restaurant is all about. It brings more concrete images to their minds," said Koh. "For example, when discussing the location of the proposed restaurant don't say 'it's in this area.' Instead, be specific and give the exact street. Or don't say you 'have a lot of experience.' Say you've 'operated restaurants since 1995.'"

An interactive pitch that poses questions to potential investors such as: "Do you want to be part of a great new restaurant concept?" had a negative impact, according to Koh. She notes there are other ways to be interactive such as posting more updates to your project pitch (e.g. "We have reached 50% of our goal!"). Successful projects approximately tripled the number of updates of unsuccessful projects.

"The restaurant industry is ultra-competitive so getting any kind of advantage through data is big. You can know everything about your concept and industry, but if you can't use the right language to communicate it, then you may not succeed," said Koh. "A simple tweak in language style could mean the difference between achieving success, or joining the thousands of restaurant concepts that never get a chance."