Dragonflies reveal how biodiversity changes in time and space

An ecological filter in a pond, such as voracious fish that feed on dragonflies and damselflies, can help ecologists predict how biodiversity loss may impact specific habitats, according to Rice University researchers who spent four years studying seasonal changes in ponds across East Texas.

In one of the first studies of its kind, the scientists show that strong environmental “filters” — in this case, predatory fish — cause dragonfly and damselfly communities to vary regularly from year to year and season to season in ponds across East Texas. The results, which appear online this week in the journal Ecology Letters, show how an ecological filter can help ecologists predict how biodiversity loss may impact specific habitats.

Thousands of Earth’s species are becoming extinct each year and the rate is increasing. Scientists have struggled to predict consequences of biodiversity loss, in part because of the uncertainty about natural variations in composition of communities across time and space.

“Ecologists tend to think about biodiversity in space — we locate biodiversity hotspots and use maps to show how biodiversity varies in different habitats — but not in time,” said Volker Rudolf, associate professor of biosciences at Rice and the lead scientist on the new study. “In reality, biodiversity changes over time just as much and in many different ways.

“There are ecological theories that suggest that community dynamics should be connected in both time and space, but we typically just infer the temporal dynamics from the spatial patterns,” he said. “In a sense, people have sort of done this backward. They assume that if these dynamics happen over time, then here’s what we should see in space. In our case, we don’t assume. We actually show what happens.”

In their study, Rudolf and his students collected and analyzed more than 18,000 insects, amphibians and fish in quarterly visits each year from 2011 to 2015 at 45 remote ponds in the Davy Crockett and Angelina national forests about 80 miles north of Houston.

Study co-author Nick Rasmussen said dragonflies — and their diminutive cousins, damselflies — were the perfect organisms to study biodiversity in East Texas because more than 60 species live there.

“We’ve got a lot of the tropical species, and a lot of the North American species, and if you go out and look at a specific pond, you’ll see there is a lot of variation in what species is where,” said Rasmussen, a postdoctoral researcher at the University of California, Davis, who earned his Ph.D. at Rice in 2012. “There’s a pretty good understanding that specific factors can influence what species show up in a given pond, and those could be things like fish, canopy cover, water temperature and how often the pond dries out. But on top of that, everything is seasonal. Species change with summer, winter and wet and dry seasons.”

One of the main things the team wanted to investigate was the extent that each pond varied, not just from season to season but also from year to year during the same season. By returning each fall, winter, spring and summer to the same ponds for four years, they quantified four sets of season-by-season changes (i.e., spring to summer) as well as four sets of year-to-year changes (i.e. summer to summer) for each site.

In analyzing the differences, Rudolf’s team found systematic differences in the temporal and spatial patterns of dragonfly diversity across ponds with different top predators. In ponds that were associated with the presence of predatory fish like bass, the top predators brought an order to both the type of dragonflies that were able to live in a pond and how dragonfly communities changed over the seasons and years.

“If you look at any of the fish ponds, you can observe dramatic changes in the composition of communities from season to season, but the changes are pretty consistent among years for each pond with the same fish predators,” said study lead author Benjamin Van Allen, a postdoctoral researcher at the University of California, San Diego, who earned his Ph.D. at Rice in 2014. “Looking at one fish pond throughout the year gives you a good idea of what happens in the rest of them.”

In contrast, the ponds that lacked fish showed far more diversity from pond to pond in the types of dragonfly species that were present. They also failed to change as consistently with seasons and years as ponds with strong top predators. Without a strong filter, the community of dragonflies in ponds that lacked fish “drifted” over time and did not go back to the same place each year, Van Allen said.

Co-author Chris Dibble, a postdoctoral researcher at Indiana University who earned his Ph.D. at Rice in 2014, said, “What this tells us is that if we want to get a sense of total biodiversity in habitats with strong filters, then we should pick a few example sites and measure them several times throughout the year. If no strong filter is present, then our study suggests that it would be more efficient to measure as many sites possible, but at fewer points in time. It’s also important to note that strong filters can also include strong climatic or environmental conditions, in addition to biotic factors like predators.”

Rudolf said the study suggests that ecological stress brought on by overfishing, overhunting, habitat loss and climate change could have very different effects on habitats with and without filters. He said the study shows how important it is for ecologists to account for such differences as they seek to quantify and conserve remaining biodiversity.

“These spatial and temporal components are really connected,” he said. “A common mechanism can drive them. In a larger context, that means that we can use simple rules to infer something about biodiversity and how it changes over time and space in various habitats and patches.”

Self-powered system makes smart windows smarter

Smart windows equipped with controllable glazing can augment lighting, cooling and heating systems by varying their tint, saving up to 40 percent in an average building’s energy costs.

These smart windows require power for operation, so they are relatively complicated to install in existing buildings. But by applying a new solar cell technology, researchers at Princeton University have developed a different type of smart window: a self-powered version that promises to be inexpensive and easy to apply to existing windows. This system features solar cells that selectively absorb near-ultraviolet (near-UV) light, so the new windows are completely self-powered.

“Sunlight is a mixture of electromagnetic radiation made up of near-UV rays, visible light, and infrared energy, or heat,” said Yueh-Lin (Lynn) Loo, director of the Andlinger Center for Energy and the Environment, and the Theodora D. ’78 and William H. Walton III ’74 Professor in Engineering. “We wanted the smart window to dynamically control the amount of natural light and heat that can come inside, saving on energy cost and making the space more comfortable.”

The smart window controls the transmission of visible light and infrared heat into the building, while the new type of solar cell uses near-UV light to power the system.

“This new technology is actually smart management of the entire spectrum of sunlight,” said Loo, who is a professor of chemical and biological engineering. Loo is one of the authors of a paper, published June 30, that describes this technology, which was developed in her lab.

Because near-UV light is invisible to the human eye, the researchers set out to harness it for the electrical energy needed to activate the tinting technology.

“Using near-UV light to power these windows means that the solar cells can be transparent and occupy the same footprint of the window without competing for the same spectral range or imposing aesthetic and design constraints,” Loo added. “Typical solar cells made of silicon are black because they absorb all visible light and some infrared heat — so those would be unsuitable for this application.”

In the paper published in Nature Energy, the researchers described how they used organic semiconductors — contorted hexabenzocoronene (cHBC) derivatives — for constructing the solar cells. The researchers chose the material because its chemical structure could be modified to absorb a narrow range of wavelengths — in this case, near-UV light. To construct the solar cell, the semiconductor molecules are deposited as thin films on glass with the same production methods used by organic light-emitting diode manufacturers. When the solar cell is operational, sunlight excites the cHBC semiconductors to produce electricity.

At the same time, the researchers constructed a smart window consisting of electrochromic polymers, which control the tint, and can be operated solely using power produced by the solar cell. When near-UV light from the sun generates an electrical charge in the solar cell, the charge triggers a reaction in the electrochromic window, causing it to change from clear to dark blue. When darkened, the window can block more than 80 percent of light.

Nicholas Davy, a doctoral student in the chemical and biological engineering department and the paper’s lead author, said other researchers have already developed transparent solar cells, but those target infrared energy. However, infrared energy carries heat, so using it to generate electricity can conflict with a smart window’s function of controlling the flow of heat in or out of a building. Transparent near-UV solar cells, on the other hand, don’t generate as much power as the infrared version, but don’t impede the transmission of infrared radiation, so they complement the smart window’s task.

Davy said that the Princeton team’s aim is to create a flexible version of the solar-powered smart window system that can be applied to existing windows via lamination.

“Someone in their house or apartment could take these wireless smart window laminates — which could have a sticky backing that is peeled off — and install them on the interior of their windows,” said Davy. “Then you could control the sunlight passing into your home using an app on your phone, thereby instantly improving energy efficiency, comfort, and privacy.”

Joseph Berry, senior research scientist at the National Renewable Energy Laboratory, who studies solar cells but was not involved in the research, said the research project is interesting because the device scales well and targets a specific part of the solar spectrum.

“Integrating the solar cells into the smart windows makes them more attractive for retrofits and you don’t have to deal with wiring power,” said Berry. “And the voltage performance is quite good. The voltage they have been able to produce can drive electronic devices directly, which is technologically quite interesting.”

Davy and Loo have started a new company, called Andluca Technologies, based on the technology described in the paper, and are already exploring other applications for the transparent solar cells. They explained that the near-UV solar cell technology can also power internet-of-things sensors and other low-power consumer products.

“It does not generate enough power for a car, but it can provide auxiliary power for smaller devices, for example, a fan to cool the car while it’s parked in the hot sun,” Loo said.

New clues found to common respiratory virus

By age 2, most children have been infected with respiratory syncytial virus (RSV), which usually causes only mild cold symptoms. But people with weakened immune systems, such as infants and the elderly, can face serious complications, including pneumonia and — in some cases — death.

Now, scientists studying the virus, led by researchers at Washington University School of Medicine in St. Louis, have found clues to how RSV causes disease. They mapped the molecular structure of an RSV protein that interferes with the body’s ability to fight off the virus. Knowing the structure of the protein will help them understand how the virus impedes the immune response, potentially leading to a vaccine or treatment for this common infection.

“We solved the structure of a protein that has eluded the field for quite some time,” said Daisy Leung, PhD, an assistant professor of pathology and immunology, and of biochemistry and molecular biophysics at Washington University School of Medicine in St. Louis, and the study’s co-senior author. “Now that we have the structure, we’re able to see what the protein looks like, which will help us define what it does and how it does it. And that could lead, down the road, to new targets for vaccine or drug development.”

The study is published June 30 in Nature Microbiology.

Each year in the United States, more than 57,000 children younger than 5 years old are hospitalized due to RSV infection, and about 14,000 adults older than 65 die from it.

There is no approved vaccine for RSV and treatment is limited — the antiviral drug ribavirin is used only in the most severe cases because it is expensive and not very effective — so most people with RSV receive supportive care to make them more comfortable while their bodies fight off the virus.

For people with weakened immune systems, though, fighting RSV can be tough because the virus can fight back. Scientists have long known that a non-structural RSV protein is key to the virus’s ability to evade the immune response. However, the structure of that protein, known as NS1, was unknown. Without seeing what the protein looked like, scientists were unable to determine exactly how NS1 interfered with the immune system.

“It’s an enigmatic protein. Everybody thinks it does many different things, but we’ve never had a framework to study how and why the protein does what it does,” said co-senior author Gaya Amarasinghe, PhD, an associate professor of pathology and immunology.

Leung, Amarasinghe and colleagues used X-ray crystallography — a technique that involves crystallizing the protein, bouncing X-rays off it, and analyzing the resulting patterns — to determine the 3-D structure of NS1. Then, in a detailed analysis of the structure, they identified a piece of the protein, known as the alpha 3 helix, which might be critical for suppressing the immune response.

To test their hypothesis, the researchers created different versions of the NS1 protein, some with the alpha 3 helix region intact, and some with it mutated. In collaboration with others — Rohit Pappu, PhD, the Edwin H. Murty Professor of Biomedical Engineering, Michael Holtzman, MD, the Selma and Herman Seldin Professor of Medicine, Maxim Artyomov, PhD, an assistant professor of pathology and immunology, and Christopher Basler, PhD, of Georgia State University — they tested the functional impact of helix 3 and created a set of viruses containing the original or the mutant NS1 genes, and measured the effect on the immune response when they infected cells with these viruses.

They found that the viruses with the mutated helix region did not suppress the immune response while the ones with the intact helix region did.

“One of the surprising things we found was that this protein does not target just one set of genes related to the immune response, but it globally modulates the immune response,” said Amarasinghe, also an associate professor of molecular microbiology, and of biochemistry and molecular biophysics.

The findings show that the alpha 3 helix region is necessary for the virus to dial the body’s immune response down. By suppressing the immune response, the virus gives itself a better chance of surviving and multiplying, or in other words, of causing disease. RSV usually can only cause disease in people whose immune systems are already weak, so a vaccine or treatment that targets the alpha 3 helix to prevent immune suppression may be just what people need to be able to successfully fight off the virus, the researchers said.

Discovery could influence methods to control bacteria on medical and other surfaces

A flexible tail allows swimming bacteria to thin the surrounding liquid and to free themselves when trapped along walls or obstacles. This finding could influence how bacterial growth on medical, industrial, and agricultural surfaces is controlled. The new study by researchers at Penn State University, published in a recent issue of the Royal Society journal Interface, used mathematical models to understand how bacteria with flagella — a collection of spinning hairs used for propulsion that act together like a tail — overcome forces from the flow of a liquid and navigate complex environments.

“Bacteria are the most abundant organisms on the planet and are often found in liquids,” said Mykhailo Potomkin, research associate in mathematics at Penn State and an author of the study. “We know from recent experimental studies that bacteria can reduce the effective viscosity — the internal friction — of a solution, which helps them move more easily.

“In solutions where the concentration of bacteria is large, this is due to collective movement of bacteria effectively thinning the solution, but a decrease of viscosity was also observed in dilute solutions where bacteria are less abundant,” Potomkin added. “This effect has been explained by bacterial tumbling — random changes in direction of the bacteria — but a similar decrease in viscosity was also reported in strains of bacteria that don’t perform this tumbling behavior. Our work suggests that the bacteria’s flagella may be responsible.”

Using a mathematical model, the research team demonstrated that flexible flagella allow bacteria to overcome local forces between molecules, reducing viscosity and effectively thinning the liquid. This understanding might have important implications for the creation of biomimetic materials — human-made materials that mimic biology — to alter properties of a solution for biomedical or industrial purposes.

“In order to understand whether we can control the viscosity of a solution, we need to understand how bacteria control it,” said Potomkin. “Flagella play a key role in this control. We also investigated how bacteria use flagella to navigate a more complex environment by introducing walls into our model. Bacteria tend to accumulate on walls or obstacles and they often get stuck swimming along walls. We demonstrated that having flexible elastic flagella can sometimes help bacteria to escape such entrapment, for example when nutrients are added to the solution and increase bacteria motility.”

Bacteria that build up on biomedical devices (e.g. catheters) and industrial and agricultural pipes and drains in the form of biofilms are difficult to remove and can be resistant to biocides and antibiotics. Understanding how bacteria can escape from walls could eventually inform ways to control or prevent the formation of these often damaging biofilms. Another application may be the ability to develop better ways to trap bacteria, for example to identify types of bacteria in a liquid or to filter them out.

“Our results indicate that if you want to trap bacteria, simple traps may not be enough,” said Igor Aronson, holder of the Huck Chair and Professor of Biomedical Engineering, Chemistry, and Mathematics at Penn State and senior author on the paper. “We would need to produce something more sophisticated. Using elastic flagella is one way motile bacteria respond to their environment to persist in harsh conditions.”

In addition to Potomkin and Aronson, the research team includes Leonid Berlyand, professor of mathematics at Penn State, and Magali Tournus, postdoctoral researcher at Penn State at the time of the research and current lecturer at Aix Marseille University in France. The research was funded by the National Institutes of Health and supported by the U.S. Department of Energy and the Huck Institutes of the Life Sciences.

Story Source:

Materials provided by Penn State. Note: Content may be edited for style and length.

Colon cancer nuclear pore dynamics are captured by HS-AFM

One of the key reasons for cancer mortality is caused by the highly invasive behaviour of cancer cells, which is often due to aggressive metastasis. Metastasis is facilitated by various growth factors and cytokines secreted from cells of the immune system, which operate through various signaling pathways. Remarkably, these signaling pathways enter the nucleus through the nuclear pore complex (NPC), which is supposed to act as a doorkeeper to the nucleus. NPC is in fact a nanomachine consisting of multiple copies of about 30 different proteins, collectively called nucleoporin.

Although small molecules are able to go through the nuclear pores rather freely, molecules larger than 40 kDa could do so effectively only by binding to specific transporter proteins that interact with FG-Nups (nucleoporins have repeating units of two amino acids, that are phenylalanine (which is often referred to as “F”) and glycine, “G”) which are the tentacle proteins having specific and selecting roles in pore transportation. Although different models are proposed, how FG-Nups exactly participates in the nucleus-cytoplasm transport remains largely unknown. Nonetheless, the concomitant assessment of nanoscopic structures and dynamics has been technically unfeasible, a situation prevailing throughout cell biology research. The direct visualization of NPC dynamics at nano scale resolution was thought to be “mission impossible.”The research team of Kanazawa University investigated this important issue and obtained the groundbreaking results by combined high-resolution live cell imaging, electron microscopy, and high-speed AFM (HS-AFM) which is developed by themselves to investigate the native nanoscopic spatial and temporal dynamics in NPC structures in the colon cancer cells.

1. First, they generated NPC stable cell lines expressing GFP (green fluorescent protein) and confirmed by fluorescent microscopy.

2. Next, they isolated the highly purified nuclear envelope which was confirmed by the use of negative stain electron microscopy and confocal microscopy.

3. Then, they started the observation of spatiotemporal changes at millisecond and nanometer scale of native state NPC structure in colon cancer cells by combining high resolution live cell imaging and electron microscopy.

4. Notably, they performed the observation of living nuclear envelope and nuclear pores using HS-AFM.

The research team of Kanazawa University was indeed successful in imaging the dynamics of NPC proteins in cancer cells, which are the building blocks of the nuclear pore, for the first time. MLN8237/alisertib, an apoptotic and autophagic inducer, is currently under several cancer clinical trials. This drug was reported to inhibit nucleoporin expression and activities. They visualized native and drug-treated FG-Nups by HS-AFM. In particular, the extended and retracted FG-Nups having a spider cobweb appearance were lost in drug-treated samples. The research team concluded that via HS-AFM, they visualized the deformation and loss of FG-Nups nuclear pore barrier which might be the first nano dying code discovered in the world.

The present study by the research team of Kanazawa University enabled visualization of structure and dynamics of the nuclear membrane pore at nanometer scale, and it is shown that deformation and loss of the nuclear membrane pore barrier would be one of the dying codes of cancer cells. These findings stand for a new paradigm in our understanding of nuclear transport, which has, up to this point, remained an enigmatic problem in the whole nano-medicine and cell biology field. Current findings are based on the crowning bio-imaging technology developed at Kanazawa University. This study has huge implication to use HS-AFM in medical application — acting as a novel “nano-endoscopy” to visualize intra-cellular organelle (such as nucleus and nuclear pores) molecular dynamics in cancer cells and other diseases.

Story Source:

Materials provided by Kanazawa University. Note: Content may be edited for style and length.

How the liver unclogs itself

A multi-disciplinary team of researchers from the Mechanobiology Institute, Singapore (MBI) at the National University of Singapore (NUS), the Institute of Bioengineering and Nanotechnology (IBN) of A*STAR, and BioSyM, Singapore-MIT Alliance for Research and Technology have described the mechanical principles adopted by liver cells as they remove excess bile during obstructive cholestasis. This study was published online in the Journal of Hepatology earlier this year.

The research team comprises team leader Professor Hanry Yu, who is a Principal Investigator at MBI and IBN; Mr Kapish Gupta, who is a graduate student at MBI and first author of the paper; as well as their fellow MBI researchers — Associate Professor Virgile Viasnoff, Associate Professor Low Boon Chuan, and Assistant Professor Pakorn (Tony) Kanchanawong.

New mechanism discovered in the liver’s response to blocked bile ducts

Biliary atresia is a rare, life-threatening liver disease that affects infants, and in particular, babies of Asian and African American descent. Although the cause of the disease remains unclear, the first symptoms are usually detected within weeks of birth.

Dubbed the ‘chemical factory’ of our body, the liver performs over 500 biological functions. Foremost among them is the synthesis and storage of essential biochemical substances, as well as the elimination or neutralisation of harmful toxins from the blood.

One of the most important functions of the liver is the production of bile, which is responsible for the organ’s detoxifying effects. Bile flows through a network of tubes known as the biliary tract, into the small intestine. During its passage the bile digests fats, and absorbs essential fatty acids. It also facilitates the elimination of waste products via the faeces.

In babies suffering from biliary atresia, bile accumulates in the biliary ducts. This means that liver function is ultimately impeded and without surgical intervention, long-term liver damage or cirrhosis will occur.

To date there are no drugs available to treat biliary atresia. However, there is renewed hope that this may one day change, with recent findings from research conducted at MBI revealing how liver cells already possess the ability to eliminate excess bile from tubes located inside the liver, which feed bile into the biliary ducts.

How liver cells eliminate bile from blocked ducts

The key to the liver’s ability to eliminate excess bile is the fact that the ‘tubes’ through which bile enters the biliary tract are not merely a set of inactive pipes, but are actually hollow spaces between living cells. The walls of the tubes are essentially the outside surfaces of the cells.

To investigate how the liver responds to bile accumulation, the research team used an artificial culture system, which allowed the easy manipulation of cultured liver cells. They then used high-end imaging techniques to visualise the dynamics of the tubes that develop within this culture system.

The team sought to investigate the response of the cells that line a blocked bile duct by obstructing the bile tract artificially and observing what happened. What they found was that as the bile accumulated behind the blockage, the tube began to swell or bulge, and this put pressure on the cells that make up the wall of the tube.

The key to the removal of excess bile lies in the internal structure of the cell itself. Immediately adjacent to the cell membrane is a network of protein cables or filaments known as the actin cortex. This structure serves to strengthen the cell, and help it retain its shape and integrity even when external forces are applied to the cell surface — external forces like the increased pressure from a build-up of fluid. Normally the actin cortex is able to counter the forces applied to it, and even when some damage to the network is incurred, it is quickly fixed by proteins that can reassemble the actin filaments.

However, when the pressure becomes too great, the actin cortex will rupture, and it will not be repaired. Although the bile cannot simply pass through the membrane, it can, as the researchers discovered, push the membrane into the cell, through the gap in the ruptured actin cortex. As this occurs a bubble-like vesicle forms inside the cell, and it is inside this vesicle that the bile enters and passes through the cell. The bile is essentially packaged inside these vesicles for its transport through the cell, and away from the site where it had accumulated.

Although the liver does not stop producing bile even when the biliary ducts are blocked, it is now evident that the liver does have a process in place to look after itself when a potentially damaging amount of bile builds up inside a blocked duct.

It is hoped that this mechanism may one day be therapeutically targeted to improve the prognosis for infants with biliary atresia. As the researchers showed, the rate of vesicle formation, and hence the uptake of excess bile into liver cells, can indeed be adjusted using drugs, at least in the cell culture setting. Improving the effectiveness of this naturally occurring mechanism, by increasing, for example, the rate of vesicle formation, may indeed encourage bile elimination from the blocked duct so as to avoid long-term liver damage and increase the effectiveness of surgical intervention.

Miniature technology, big hope for disease detection

The field of medicine is always on the lookout for better disease diagnostic tools — simpler, faster, and cheaper technologies to enhance patient treatment and outcomes. Currently, microfluidic bioassay devices are the preferred diagnostic tools that allow clinicians to measure the concentration of disease biomarkers within a patient’s biological sample, such as blood. They can indicate the likelihood of a disease based on a comparison of the biomarker concentration in the sample relative to the normal level. To detect this concentration, the patient’s sample is passed across a surface containing immobilized bioreceptors, or “biomarker-capturing” molecules that have been attached to this surface. A researcher can then record the biomarker abundance, determine whether the level is normal, and reach a diagnosis. Since the efficiency of these devices relies on how intact and functional the attached bioreceptors are, immobilizing these bioreceptors without causing damage has proved daunting.

Over the last two decades, microcontact printing, which uses a rubber stamp to immobilize the bioreceptors, has been established as a robust method to create a variety of assays with multiple applications. Yet this method also has its flaws, particularly when utilized at the nano scale — the scale where proteins and DNA reign. At this scale, the harsh and elaborate techniques currently used compromise the device’s resolution, whether by deforming the stamp or damaging the bioreceptors, thus yielding data somewhat unmanageable for use in diagnostics or other applications. However, in a recent article published in the journal Analyst, researchers at the Okinawa Institute of Science and Technology Graduate University (OIST) describe a new sequence of printing steps that have rectified these issues.

For microcontact printing, “you need a stamp, an ink, and a surface, and then you create your pattern on your surface. It’s as simple as that,” explains Shivani Sathish, OIST PhD student in the Micro/Bio/Nanofluidics Unit, and first author on the paper.

The stamp is made of polydimethylsiloxane, which is a flexible solid similar to the rubber used in everyday stamps. The ink is a solution composed of silicon- and oxide-containing molecules called APTES, and the surface is glass. After coating the stamp with the ink, the stamp is pressed onto the glass, and then removed after a short incubation. The result is a patterned layer of APTES on the glass — a checkerboard of regions with or without APTES. Next, a microfluidic device, which contains one or more microchannels configured to guide fluid through specified pathways, is sealed over the patterned glass. Finally, the bioreceptors are chemically linked to the APTES regions within the microfluidic channels. The device as a whole is about the size of a postage stamp.

The system is now ready for use as a diagnostic assay. To carry out the assay, a fluid sample from a patient is delivered through the microfluidic device attached to the glass. If the pertinent disease biomarker is present, the molecule will “stick” to the areas containing the bioreceptors.

What is important about the APTES solution is its convenient chemistry. “Depending on your bioreceptor of interest, you just have to choose the appropriate chemistry to link the molecule with the APTES,” Ms. Sathish explains. Or in other words, one stamp can be used to prepare an assay with the ability to immobilize a variety of different bioreceptors — one stamp allows for multiple tests and diagnoses on a single surface. This feature would be advantageous for diagnosing complex diseases such as cancer, which relies on tests that can detect multiple markers to improve the diagnosis.

In their research, Ms. Sathish and colleagues developed an improved technique to create the most optimal disease diagnostic device for use at the nano scale. Here, they first patterned nanoscale features of APTES using an ink made of APTES in water, as opposed to harsh chemicals, which eliminated the stamp-swelling issue. Then, they immobilized the bioreceptors onto the surface as the very last step of the process, after patterning the APTES and attaching the microfluidic device. By attaching the bioreceptors as the final step, the researchers avoided exposing them to extreme and damaging conditions. They then demonstrated the efficacy of the final device by running an assay to capture the biomarkers interleukin 6 and human c-reactive protein, two substances that are often elevated in the body during inflammation.

“The final goal is to create a point-of-care device,” explains OIST Professor Amy Shen, who headed the research.

“If you get your bioreceptors pre-immobilized within microfluidic devices you can then use them as diagnostic tools as and when required,” Ms. Sathish continues. “[Eventually] instead of having a whole clinical team that processes your sample…we’re hoping that the patients can do it themselves at home.”

The Black Forest and climate change

As the climate change progresses, droughts are expected to become more and more common and more intense in Europe, as in many parts of the globe. However, many plants are not able to handle this kind of climate. This includes the Norway spruce, which is Germany’s most important commercial tree species and accounts for the majority of trees in the Black Forest. Valentia Vitali and Prof. Dr. J├╝rgen Bauhus from the Chair of Silviculture at the University of Freiburg are thus studying other types of needle-leaved conifers to find alternatives. Conifers play a far greater role in commercial forestry and climate protection than broad-leaved trees.

In their article “Silver Fir and Douglas Fir Are More Tolerant to Extreme Droughts than Norway Spruce in South-Western Germany” published in the journal Global Change Biology, the scientists concluded that the native silver fir and the Douglas fir, which was imported from the Americas, are suitable tree replacements for the Norway spruce in the long run.

Extreme droughts are believed to be one of the greatest challenges of climate change facing commercial forestry in the medium term, the researchers said. In their study of how forests in Central Europe might adjust to climate change, Vitali and Bauhus studied the past growth of more than 800 trees at different altitudes in the Black Forest. They looked at annual tree rings before, during, and after the extreme summer droughts of 1976 and 2003 to determine which conifers best withstand droughts and which recover the quickest and fullest after dry spells.

They discovered that silver and Douglas firs are far less affected by drought than spruces. That the silver fir, which suffered severely from acid rain falls in the 1970s and 1980s and was considered endangered, is now an alternative native tree species for the future is both a positive and surprising finding, the scientists said. While the Douglas fir is the more productive replacement species for the Norway spruce, silver firs have a greater positive effect on biodiversity. The scientists therefore recommend that spruce forests, which are at high risk of drought stress, be replaced with mixed-species forests silver and Douglas firs, with silver firs being the more suitable tree for higher altitudes in the Black Forest.

Story Source:

Materials provided by University of Freiburg. Note: Content may be edited for style and length.

Japanese children learn to write through rhythm

How do we learn to write? Associate Professor NONAKA Tetsushi (Kobe University Graduate School of Human Development and Environment) looked at the development of writing skills in Japanese first-grade students learning the hiragana script. By quantifying their pen movements, he revealed the process of learning distinct temporal patterns of movement in such a way to differentiate a set of subtle features of each symbol. These aspects of handwriting development have been largely neglected in research carried out in Latin alphabet communities. The findings were published on June 13 in Developmental Psychobiology.

Previous research based on the Latin alphabet explains the acquisition of writing skills during childhood as a combination of two processes: the acquisition of visual representations and the development of fine motor skills to produce the desired trajectory of the pen. This study looked at the development of movement dynamics of handwriting in 1st graders at the Kobe University Elementary School who learned to write hiragana, a phonetic script used for Japanese. He examined how their movements were influenced by the social norms of the classroom environment in which those 1st graders participated over the first three months of the primary school.

During the study, the children were repeatedly encouraged to pay attention to the specific requirements for writing each character, including stroke endings, stroke order and rhythm of movement. While he observed individual variation in handwriting development among six students studying in the same classroom, two common trends were quantitatively demonstrated. Firstly, the pen movements became clearly differentiated for each type of stroke ending (stop, sweep or jump). Secondly, a consistent temporal structure of movement gradually emerged for each stroke.

This demonstrates that the process of handwriting development as explained by Latin alphabet-based research — acquiring fine motor skills in hands, plus storing the shapes in the head — cannot fully explain the handwriting skill development process for hiragana script. At least in this particular language community, learning the temporal pattern of movement corresponding to a letter seems highly important, based on which the invariant features of a letter — the traces of the specific temporal pattern of movement — can be discriminated as such. The study also suggests that the process of learning to write by differentiating physical movements may be linked to a phenomenon specific to Chinese character-based cultures known as “air writing,” when people unconsciously move their fingers while trying to recall a certain character.

Story Source:

Materials provided by Kobe University. Note: Content may be edited for style and length.