It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
LEIBNIZ INSTITUTE OF PLANT GENETICS AND CROP PLANT RESEARCH
IMAGE: RESEARCHERS FROM IPK LEIBNIZ INSTITUTE HAVE INVESTIGATED HOW THE BEHAVIOR OF AN INDIVIDUAL WHEAT PLANT UNDER LIMITING LIGHT CONDITIONS INFLUENCES THE PERFORMANCE OF THE WHOLE COMMUNITY.view more
CREDIT: IPK LEIBNIZ INSTITUTE/ T. SCHNURBUSCH
One of the most significant drivers of crop evolution stems from the changes in the selection associated with the shift of plants from a highly heterogeneous and biodiverse natural environment into a homogeneous monoculture environment. Competition for resources has been considered a prevalent force in structuring plant populations under natural selection, often favoring the most competitive individual plants in a particular environment. The architecture and behavior of successful genotypes as individual plants differ from that of genotypes thriving in a community. Individual plant fitness is increased by ‘selfish’ traits, which may, like in humans, negatively impact the performance of the community
“Agriculture relies on community performance”, emphasizes Prof. Dr. Thorsten Schnurbusch, head of the research group “Plant Architecture” at IPK Leibniz Institute. “But the environment in which crops are grown, i.e. their ecology in the agricultural context, their agroecology, is hardly explored and less understood. It is surprising how less we know about the interactions among plants grown in a dense, real-world community.”
Today, crop plants are grown in high-density stands where they experience limited light availability due to mutual shading. “Therefore, by simulating canopy shade, we may get closer to the conditions plants are experiencing in high-density stands in the field, which may be helpful for studying and selecting plants for higher grain yield”, says Dr. Guy Golan, first author of the current study. “Cooperative behaviors and highly fertile inflorescences in a light-limited/shaded environment are most important for a thriving grain crop community.”
The researchers found behaviors that nourish the fitness of the individual plant as non-beneficial and, in some cases, detrimental to the performance of the whole community. The results have recently been published in the “Plant, Cell & Environment” journal as part of the Special Issue: Tradeoffs in Plant Responses to the Environment. Moreover, the researchers say that multiple phenotypes attained under simulated shade could better explain community performance of the wheat crop, advocating the use of simulated shade in breeding high-yielding cultivars.
“Having much deeper insights into these interactions, and specifically understanding their molecular and genetic components is very important to develop more resilient and resource-efficient crop plants for the future”, says Prof. Dr. Thorsten Schnurbusch. “Embracing an agroecological genetics approach may optimize communal yield by better matching crops to their environment, as either monoculture or a mixture.”
A ‘near total’ lack of transparency is making it impossible to assess the quality of corporate-led ecosystem restoration projects, according to a Lancaster University-led study published today in Science.
Efforts to rebuild degraded environments are vital for achieving global biodiversity targets. The United Nations has launched a Decade on Ecosystem Restoration, and in recent years businesses around the world have collectively pledged to plant billions of trees, hundreds of thousands of corals and tens of thousands of mangroves, with corporate-led projects offering huge potential to restore damaged and lost ecosystems around the globe.
An international team of scientists analysed publicly available sustainability reports released by 100 of the world’s largest companies and found that around two thirds of these global corporations are undertaking ecosystem restoration. However, the results highlight that despite many businesses claiming to actively rebuild damaged ecosystems, we know very little about what is actually being achieved.
The study reveals that more than 90 per cent of corporate-led restoration projects fail to report a single ecological outcome. Further, around 80 per cent of projects do not reveal how much money is invested in restoration, and a third fail to even state the area of habitat that they aim to restore.
“Restoring degraded ecosystems is an urgent challenge for this decade, and big businesses have the potential to play a vital role,” said Dr Tim Lamont of Lancaster University, lead author of the study. "With their size, resources and logistics expertise, they could help deliver the large-scale restoration we need in many places.
“However, at the moment there is very little transparency, which makes it hard for anyone to assess if projects are delivering benefits for ecosystems or people.
“When a business says it has planted thousands of trees to restore habitat and soak up carbon – how do we know if this has been delivered, if the trees will survive, and if it has resulted in a functioning ecosystem that benefits biodiversity and people? In many cases, we’ve found that the evidence provided by large corporations to support their claims is insufficient.”
Many countries require businesses to conduct Environmental Impact Assessments (EIAs) to quantify and reduce their environmental damage, and other private-sector initiatives also encourage companies to measure and disclose their biodiversity impacts. However, the study finds that current guidelines and legal frameworks around ecosystem restoration are inadequate, and are not yet resulting in appropriate reporting by businesses.
The researchers are calling for more transparency around the reporting of corporate-led ecosystem restoration projects, and for reporting to be more consistently centred around scientific principles that determine ecosystem restoration success.
Professor Jan Bebbington, Director of the Pentland Centre for Sustainability in Business at Lancaster University and co-author of the study, said: “It is clear that corporate reporting around restoration projects needs to be improved. Guidelines need to ensure that corporations are transparent when reporting and quantifying the aims and results of their sustainability efforts.
“Greater transparency will ensure that some businesses can’t get away with doing ineffective restoration and claiming reputational gain for it. But transparency is also vital for the credibility of those corporate-led schemes that are genuinely attempting to deliver significant environmental benefits. And transparency also provides opportunities for others to learn.
“There is definitely potential for businesses to be important global leaders in the restoration space. But that potential will go unrecognised, and the maximum benefits unrealised, without better regulation and transparency.”
The researchers say new improved reporting guidelines around ecosystem restoration should:
Recommend that companies clearly differentiate between restoration activities that merely mitigate the negative environmental impacts of a business’ operations from those that aim to provide wider climate, biodiversity and social justice outcomes.
Recommend a principle-based approach, drawing from conservation science, for planning and reporting, so that restoration projects in a range of different contexts can all maintain high standards across core areas.
Ensure corporations engage with and empower local stakeholders to co-design restoration projects from the outset.
Professor Rachael Garrett, a co-author of the study from the University of Cambridge, said: “Ultimately, if big businesses are going to contribute effectively to the UN Decade on Ecosystem Restoration, there needs to be transparency and consistency in reporting.
“This is in the interest of the businesses themselves, who stand to gain from demonstrating to their customers, shareholders, employees and the wider public that they are making meaningful impacts with their declared restoration efforts.
"The world’s largest corporations have the potential to lift ecosystem restoration efforts to an unprecedented scale. But their involvement has to be managed with proper evidence and accountability, to make sure the outcomes are beneficial and fair for everyone.”
The study, which was funded by the Royal Commission of 1851 and the Natural Environment Research Council (NERC), is outlined in the paper ‘Hold big business to task on ecosystem restoration’, published today in Science.
The paper’s authors are: Dr Timothy Lamont, Professor Jos Barlow, Professor Jan Bebbington and Professor Nicholas Graham of Lancaster University; Professor Thomas Cuckston of the University of Birmingham; Rili Djohani MSc of the Coral Triangle Center in Indonesia; Professor Rachael Garrett of ETH Zurich and Cambridge University; Professor Holly Jones of Northern Illinois University and Dr Tries Razak of the National Research and Innovation Agency in Indonesia.
IMAGE: GLACIER ICE IN LECONTE BAY NEAR PETERSBERG, ALASKA.view more
CREDIT: OREGON STATE UNIVERSITY
CORVALLIS, Ore. – Oregon State University research has uncovered a possible clue as to why glaciers that terminate at the sea are retreating at unprecedented rates: the bursting of tiny, pressurized bubbles in underwater ice.
Published today in Nature Geoscience, the study shows that glacier ice, characterized by pockets of pressurized air, melts much more quickly than the bubble-free sea ice or manufactured ice typically used to research melt rates at the ocean-ice interface of tidewater glaciers.
Tidewater glaciers are rapidly retreating, the authors say, resulting in ice mass loss in Greenland, the Antarctic Peninsula and other glacierized regions around the globe.
“We have known for a while that glacier ice is full of bubbles,” said Meagan Wengrove, assistant professor of coastal engineering in the OSU College of Engineering and the leader of the study. “It was only when we started talking about the physics of the process that we realized those bubbles may be doing a lot more than just making noise underwater as the ice melts.”
Glacier ice results from the compaction of snow. Air pockets between snowflakes are trapped in pores between ice crystals as the ice makes its way from the upper layer of a glacier to deep inside it. There are about 200 bubbles per cubic centimeter, meaning glacier ice is about 10% air.
“These are the same bubbles that preserve ancient air studied in ice cores,” said co-author Erin Pettit, glaciologist and professor in the OSU College of Earth, Ocean, and Atmospheric Sciences. “The tiny bubbles can have very high pressures – sometimes up to 20 atmospheres, or 20 times normal atmospheric pressure at sea level.”
When the bubbly ice reaches the interface with the ocean, the bubbles burst and create audible pops, she added.
“The existence of pressurized bubbles in glacier ice has been known for a long time but no studies had looked at their effect on melting where a glacier meets the ocean, even though bubbles are known to affect fluid mixing in multiple processes ranging from industrial to medical,” Wengrove said.
Lab-scale experiments performed in this study suggest bubbles may explain part of the difference between observed and predicted melt rates of tidewater glaciers, she said.
“The explosive bursts of those bubbles, and their buoyancy, energize the ocean boundary layer during melting,” Wengrove said.
That carries huge implications for the way ice melt is folded into climate models, especially those that deal with the upper 40 to 60 meters of the ocean – the researchers learned glacier ice melts more than twice as fast as ice with no bubbles.
“While we can measure the amount of overall ice loss from Greenland over the last decade and we can see the retreat of each glacier in satellite images, we rely on models to predict ice melt rates,” Pettit said. “The models currently used to predict ice melt at the ice-ocean interface of tidewater glaciers do not account for bubbles in glacier ice.”
Right now, data from NASA attributes about 60% of sea level rise to meltwater from glaciers and ice sheets, the authors note. More accurate characterization of how ice melts will lead to better predictions of how quickly glaciers retreat, which is important because “it’s a lot more difficult for a community to plan for a 10-foot increase in water level than it is for a 1-foot increase,” Wengrove said.
“Those little bubbles may play an outsized role in understanding critical future climate scenarios,” she added.
The Keck Foundation, the National Science Foundation and the National Geographic Society funded the research, which also included Jonathan Nash and Eric Skyllingstad of the OSU College of Earth, Ocean, and Atmospheric Sciences and Rebecca Jackson of Rutgers University.
Melting of glacier ice enhanced by bursting air bubbles
ARTICLE PUBLICATION DATE
7-Sep-2023
Disclaimer: AAAS
West Antarctic ice sheet has not reached its tipping point towards irreversible collapse – yet, new research finds
There is a limited window of time before large-scale, irreversible ice loss in the Antarctic starts, according to new research from Northumbria University
In the first study of its kind, researchers from Northumbria University examined the current state of the Antarctic ice sheet, which reveals no evidence that a tipping point towards large-scale, irreversible collapse has been crossed – yet.
However, researchers found even with no additional global warming, an irreversible collapse of some regions of the West Antarctic ice sheet is possible.
While ice loss in Antarctica is expected to continue, authors say these studies give slight hope it might be possible to avoid or delay the tipping point, but with urgent action.
There is a limited window of time before large-scale, irreversible ice loss in the Antarctic starts, according to new research from Northumbria University.
For the first time, two collaborative papers published today in The Cryosphere journal, examined whether the Antarctic ice sheet has already reached a tipping point towards permanent unstoppable retreat.
The ongoing ice loss in Antarctica has raised concerns that the West Antarctic ice sheet might already be destabilised and ‘past the point of no return’.
However, researchers have now systematically analysed this question and found there is no evidence that it has already reached its tipping point.
The modelling study – carried out by Northumbria University and several research institutions across Europe – used three different computer models to run a series of simulations to conduct a thorough inspection looking for signs of irreversible retreat of the Antarctic ice sheet in its present form.
Authors of the study say whilst ice loss in Antarctica will continue in the future, these results give slight hope that it might still be possible to avoid or delay crossing the tipping point, if urgent action is taken.
Dr Emily Hill, Research Fellow at Northumbria University and report co-author, said: “The implications are profound. We used three different numerical models which all showed that we have not yet crossed a tipping point that leads to irreversible ice loss in Antarctica.
“Using several models makes our findings even more convincing, and it is reassuring to know that we haven’t yet passed the point of no return.”
However, the researchers also ran hypothetical simulations to investigate how the ice sheet might evolve if current climate conditions stay as they are. They found that even with no additional global warming, an irreversible collapse of some marine regions of West Antarctica’s ice sheet is possible in the future.
One of their models shows the earliest that this could happen is within 300-500 years under current conditions, warning that accelerating climate change is likely to shorten this timescale further.
Antarctica’s ice masses store enough water to raise sea levels by several metres around the globe and remain one of the greatest uncertainties in future projections of the effects of climate change.
Dr Ronja Reese, Vice-Chancellor’s Fellow at Northumbria University and report co-author, said:“Accelerated ice loss at the margins of the ice sheet could signal a collapse of larger marine regions. Our experiments show that an irreversible collapse in some marine regions in West Antarctica is possible for the current climate conditions.
“Importantly, this collapse is not happening yet, as our first study shows, and it evolves over thousands of years. But we would expect that further climate warming in the future will speed this up substantially.”
The research forms part of a major £4 million EU-funded study on Tipping Points in Antarctic Climate Components (TiPACCs) bringing together experts from the UK, Norway, Germany and France to investigate the likelihood of abrupt changes in the movement of ice in the Antarctic region.
Petra Langebroek, Research Director at the Norwegian Research Centre (NORCE), and Scientific Coordinator of the European TiPACCs Project, said:“I am very proud to see this work published. This tight collaboration across different European institutes has resulted in major progress in our understanding of Antarctic ice sheet stability and tipping points.
“This is somewhat good news. We have not yet crossed these tipping point in Antarctica, which – in theory – means that the ongoing ice loss can be reduced or even stopped. Unfortunately, our research also shows that with ongoing climate change, we are headed to crossing tipping points in West Antarctica.”
Northumbria University is home to one of the world’s leading groups in the studies of the interactions between ice sheets and oceans. The team of researchers are working to explore the future of ice sheets and glaciers worldwide in a warming world. This involves understanding the causes of ongoing changes in Antarctica, Greenland and alpine areas, as well as assessing future changes and resulting impacts on human environments globally.
Pre-prints of the papers are available as follows:
1The stability of present-day Antarctic grounding lines – Part 2: Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded.Ronja Reese, Julius Garbe, Emily A. Hill, Benoît Urruty, Kaitlin A. Naughten, Olivier Gagliardini, Gaël Durand, Fabien Gillet-Chaulet, G. Hilmar Gudmundsson, David Chandler, Petra M. Langebroek, and Ricarda Winkelmann. https://tc.copernicus.org/preprints/tc-2022-105/
2The stability of present-day Antarctic grounding lines – Part 1: No indication of marine ice sheet instability in the current geometry. Emily A. Hill, Benoît Urruty, Ronja Reese, Julius Garbe, Olivier Gagliardini, Gaël Durand, Fabien Gillet-Chaulet, G. Hilmar Gudmundsson, Ricarda Winkelmann, Mondher Chekki2, David Chandler, and Petra M. Langebroek.https://tc.copernicus.org/preprints/tc-2022-104/
POTSDAM INSTITUTE FOR CLIMATE IMPACT RESEARCH (PIK)
Antarctica’s vast ice masses seem far away, yet they store enough water to raise global sea levels by several meters. A team of experts from European research institutes has now provided the first systematic stability inspection of the ice sheet’s current state. Their diagnosis: While they found no indication of irreversible, self-reinforcing retreat of the ice sheet in West Antarctica yet, global warming to date could already be enough to trigger the slow but certain loss of ice over the next hundreds to thousands of years.
“With more and more ice being lost in Antarctica over the last years, concerns have been raised whether a tipping point has already been crossed and an irreversible, long-term collapse of the West Antarctic Ice Sheet has already been initiated,” explains Ronja Reese from the Potsdam Institute for Climate Impact Research (PIK) and the Northumbria University, Newcastle. “The results of our studies deliver two messages: First, while a number of glaciers in Antarctica are retreating at the moment, we find no indication of irreversible, self-reinforcing retreat yet, which is reassuring. However, our calculations also clearly indicate that an onset of an irreversible retreat of the ice sheet in West Antarctica is possible if the current state of the climate is sustained.”
The main driver of ice loss in West Antarctica is relatively warm ocean water that amplifies melting underneath the ice shelves, which are the floating extensions of the grounded ice sheet. Melting of these ice shelves can enhance ice loss as it speeds up the grounded sections of the ice sheet. That is why the Antarctic margin with its grounding lines – the zone where the grounded and the floating ice are connected – is a key indicator of ice sheet health. An accelerated retreat of the grounding lines could indicate a forthcoming collapse of large marine regions of West Antarctica’s ice sheet - those parts of the ice sheet that are grounded below sea level.
Evolving over 10,000 years, triggered today: irreversible ice-loss and sea-level rise
Using state-of-the-art ice sheet models, the researchers not only conducted a thorough inspection of signs of irreversible retreat of marine sectors of the Antarctic ice sheet at present, they also ran simulations to investigate how the ice sheet would evolve over the next 10,000 years if current conditions remained unchanged. These hypothetical experiments indicate that even with no additional warming beyond what we have already experienced today, an irreversible collapse of some marine regions of West Antarctica’s ice sheet is possible. Because the ice reacts to changes in temperature very slowly, the authors find that collapse occurs in their simulations at the earliest in 300 to 500 years from now, under current climate forcing. A full collapse would take centuries to millennia.
“The thing with sea-level rise from Antarctica is not that changes would happen overnight as an immediate threat to coastal communities. The process of melting would happen over hundreds or thousands of years. However, the cause could be human actions today, as they have the power to trigger and commit a future of 10,000 years to several meters of global sea-level rise. And stronger warming in the future would even speed up this process,” Julius Garbe from PIK stresses.
Changes in ice discharge from Antarctica remain one of the greatest uncertainties in future projections of global sea-level rise. “The Antarctic ice is our ultimate heritage of the past, millions of years old and often coined ‘eternal’ ice. But our work shows: while current ice loss may still be reversible, a destabilization of marine sectors of the ice sheet could initiate a long-term ice loss that is slow but certain. Climate change today could already be enough to tip the scales, that is concerning. Yet, with West Antarctica not destabilized yet there is still a chance to mitigate at least some of the risk by ambitious climate action,” Ricarda Winkelmann from PIK concludes.
Emily A. Hill, Benoît Urruty, Ronja Reese, Julius Garbe, Olivier Gagliardini, Gaël Durand, Fabien Gillet-Chaulet, G. Hilmar Gudmundsson, Ricarda Winkelmann, Mondher Chekki, David Chandler, Petra M. Langebroek (2023): The stability of present-day Antarctic grounding lines – Part 1: No indication of marine ice sheet instability in the current geometry, The Cryosphere, 17, 3739–3759 [DOI: 10.5194/tc-17-3739-2023]
Ronja Reese, Julius Garbe, Emily A. Hill, Benoît Urruty, Kaitlin A. Naughten, Olivier Gagliardini, Gaël Durand, Fabien Gillet-Chaulet, G. Hilmar Gudmundsson, David Chandler, Petra M. Langebroek, Ricarda Winkelmann (2023): The stability of present-day Antarctic grounding lines – Part 2: Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded, The Cryosphere, 17, 3761–3783 [DOI: 10.5194/tc-17-3761-2023]
The world saw another year full of extreme weather events resulting from climate change in 2022, from intense storms to soaring temperatures and rising sea levels. Antarctica was no exception, according to new research published this week.
In the 33rd annual State of the Climate report, an international assessment of the global climate published Sept. 6 in the Bulletin of the American Meteorological Society, CU Boulder researchers report that the planet’s coldest and driest continent experienced both an unprecedented heatwave and extreme precipitation last year.
“My hope is that the public starts to see both the fragility and complexity of these polar regions,” said Rajashree Tri Datta, a research associate in the Department of Atmospheric and Oceanic Sciences who contributed to sections of the report related to Antarctica and the Southern Ocean.
While Antarctica may seem isolated from the rest of the world, changes to the icy continent could significantly impact the rest of the world.
“Most of the planet’s fresh water is held on the ice sheet of Antarctica. What happens there ends up affecting coasts across the world, and what affects coasts across the world impacts everything from agriculture to migration patterns,” Datta said.
In recent years, scientists have observed rapid sea ice decline and enhanced warming there. Regions of Antarctica, such as the West Antarctic Ice Sheet, have started to lose ice rapidly, contributing to sea level rise.
Datta and her team report that for six days last March, a large region of East Antarctica experienced temperatures exceeding 18 degrees Fahrenheit (10 degrees Celsius) above the historic March average from 1991 to 2020. The temperature recorded at a weather station in the interior of East Antarctica reached a record-breaking 14.7 F (-9.6C) on March 16, 2022, more than 79 F (44 C) higher than the average March temperature at that location.
Normally, March marks the transition from summer to winter in Antarctica, and the temperature drops rapidly. Following the heatwave, the Conger Ice shelf, a floating tongue of ice the size of Rome, collapsed in East Antarctica. This ice shelf had become increasingly vulnerable over the years. The collapse of floating ice shelves can often hasten the loss of upstream glaciers, resulting in ice loss and sea level rise.
As people around the world also experienced more frequent and intense heatwaves in 2022, Datta said the team’s research provides an opportunity to communicate with the public about climate change in Antarctica in a way that resonates with them.
“They know what a heatwave means. They experience it in their daily lives, and it is impacting Antarctica as well, although in very different ways” Datta said.
Unprecedented snowfall too
East Antarctica also saw an unprecedented amount of snowfall last March, tripling the month’s mean precipitation in some locations compared with the March average between 1991 and 2020. As a result, the annual balance of snow and ice retained on the surface of the ice sheet reached the highest value in the 40 years since the observational data became available.
“The strong precipitation this year is very interesting, because it offsets the ice loss around the margins of Antarctica,” Datta said. “The snowfall this year actually protected the world against sea level rise.”
Weather phenomena called atmospheric rivers—much like those that fueled record flooding in California this year—contributed to both the heatwave and the record precipitation, Datta said. These storms pull moisture from lower latitudes and delivered warm air and a large amount of precipitation to Antarctica in 2022.
While precipitation in Antarctica typically takes the form of snow, changes in these atmospheric rivers could bring enough heat to contribute to more surface melt or bring rain instead in the future, driving sea levels higher and impacting billions of people around the world, she said. Greenland, which is much warmer than Antarctica, is already experiencing many of these impacts.
The State of the Climate report, a collaboration of more than 570 international scientists, also reported that Earth’s greenhouse gas concentrations reached a new record last year. The global annual average atmospheric carbon dioxide concentration was 50% greater than the pre-industrial level, the highest measured amount in modern observational records. The amount of heat stored in the ocean continued to increase, as did global sea levels, reaching about 4 inches on average above the 1993 mean.
In another section of the report, Twila Moon, the deputy lead scientist at the National Snow and Ice Data Center at CU Boulder, reported that weather pattern shifts are also affecting the planet’s other pole.
"Observations over the past forty-plus years show a transition to a wetter Arctic, with seasonal shifts and widespread disturbances influencing the flora, fauna, physical systems, and peoples of the Arctic," Moon and her team wrote.
"The report adds pieces to the larger puzzle of how climate change can impact Antarctica,” Datta said. “Many of these dramatic events in 2022, and further research into their causes and effects, can arm us with a better understanding of our potential future.”
Herpes is not only unpleasant but it can, in some cases, also have dangerous complications and life-threatening consequences. In the journal Angewandte Chemie, a research team has now introduced a completely new approach for treating herpes. Their method is based on the inhibition of an enzyme that is needed for the release of newly formed virus particles from infected cells.
Just before an important interview or anticipated first date—always when you least need it—you feel a tingling and itching on your lip. A glance in the mirror reveals the first little blisters: herpes is back. The majority of adults carry the instigator in their bodies because, once infected, herpes simplex Type 1 viruses (HSV-1) settle into nerve ganglia. They remain in the body throughout a person’s life, inactive most of the time. If the immune system is temporarily weakened, maybe by anxiety or stress, too much sunlight, hormonal fluctuations, or a cold, an outbreak may occur. This is annoying and painful but usually harmless. However, this is not always the case: in some immunocompromised individuals or newborns there can be severe and sometimes life-threatening consequences. Dangerous complications are also a threat if the virus infects the eyes or brain; for example, corneal herpes is one of the leading causes of infection-induced blindness. Antiviral drugs can curb herpes infections but not fully vanquish them.
A team from the University of Georgia, Athens (USA), the University of Illinois at Chicago (USA), and the University of Utrecht (Netherlands), led by Deepak Shukla and Geert-Jan Boons, has now developed an alternative method for the treatment of herpes.
HSV-1 viruses dock to heparan sulfates, molecules that are made of many sugar (saccharide) units and are found in the extracellular matrix and plasma membranes of our cells. Once bound, the viruses can enter the cells. In the late stages of infection the virus causes the infected cells to increase production of heparanase, an enzyme involved in the remodeling of the extracellular matrix. It splits heparan sulfates off the surface of the cell—a prerequisite for the release of the viruses newly produced in the cell so that they can spread to other cells and tissues. The idea behind this project is to block the heparanase.
The team synthesized a series of oligosaccharides that have structures like those of heparan sulfates but are not split by the heparanase enzyme. Molecules made of six or eight saccharides strongly inhibit heparanase. By using complementary computer studies, the team was able to model the way these oligosaccharides are arranged in the enzyme’s binding cavity and determine which molecular interactions are responsible for the strong binding. Treatment of corneal cells infected with HSV-1 with the active oligosaccharides had the effect of inhibiting the virally induced excretion of heparan sulfates, significantly reducing the spread of the virus.
In addition, inhibition of heparanase through the new inhibitors can impede the migration and proliferation of immortalized cells (that is, cells with uncontrolled cell growth). This enzyme has been strongly implicated in cancer metastasis, suggesting another potential application for the inhibitors in the future.
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About the Author
Geert-Jan Boons is the UGA Foundation Distinguished Professor in Biochemical Sciences at the Department of Chemistry and the Complex Carbohydrate Research Center (CCRC) of the University of Georgia (USA), and Professor and Chair of the Department of Medicinal and Biological Chemistry of Utrecht University (The Netherlands). His group is developing methods for synthesizing complex glycans and glycoconjugates that are being used for biological and biomedical explorations with a focus on infectious diseases, immunology, and cancer.
