Protecting the intellectual abilities of people at risk for psychosis

A UNIGE team has found that a class of drugs can protect the development of intellectual abilities in people at risk of psychosis, if prescribed before adolescence

UNIVERSITÉ DE GENÈVE

Research News

 

IMAGE: EFFECTS OF SSRIS ON BRAIN AND INTELLECTUAL DEVELOPMENT. ON THE LEFT SIDE: BRAIN MAP SHOWING REGIONS OF THE BRAIN PROTECTED BY THE PROLONGED ADMINISTRATION OF SSRIS COMPRISING A NETWORK OF... view more 

CREDIT: VALENTINA MANCINI

One person in 2000 suffers from a microdeletion of chromosome 22 that can lead to the development of psychotic disorders, such as schizophrenia, in adolescence. In addition to symptoms such as hallucinations or delusions, psychotic disorders also comes with a progressive decline in intelligence quotient (IQ). If current drug treatments are successful in containing psychotic symptoms, nothing can be done to prevent the deterioration of intellectual skills that leads to loss of autonomy. Researchers at the University of Geneva (UNIGE), Switzerland, have discovered that prescription of selective serotonin reuptake inhibitors (SSRIs) - a class of drugs used to treat anxiety and depression -in late childhood can reduce the deterioration of intellectual abilities, and have a neuroprotective effect on some of the brain regions affected by the psychotic illness. This study, to be read in the journal Translational Psychiatry, opens up a new field of research and new hope for people affected by the microdeletion of chromosome 22.

The average IQ is around 100 points. However, for people who may develop a psychotic illness, such as those with a microdeletion of chromosome 22, the average drops to 70-80 points. "The problem is that when a psychotic disorder occurs, such as schizophrenia, the brain frontal lobe and the hippocampus are particularly affected, which leads to the gradual deterioration of already below-average intellectual capacities", explains Valentina Mancini, a researcher in the Department of Psychiatry at UNIGE Faculty of Medicine and first author of the study. From then on, the average IQ drops to around 65-70 points, leading to a loss of autonomy that requires a protected environment. "At present, drug treatments manage to contain psychotic symptoms, such as hallucinations, anxiety or distortion of reality, but there is no treatment that can reduce the deterioration of affected people's intellectual capacities", notes the Geneva researcher.

200 patients followed over a 20 years period reveal a possible solution

The team of Stéphan Eliez, professor in the Department of Psychiatry at UNIGE Faculty of Medicine, has been following 200 patients affected by the microdeletion of chromosome 22 for the past 20 years. "30 to 40% of them developed schizophrenia psychotic disorder", he explains. "Thanks to this cohort, we found that people suffering from this syndrome lost 7 to 8 IQ points from childhood to adulthood. This figure rises to 15 IQ points for those who developed psychotic disorders."

Yet the physicians noted that two to three teenagers a year are exceptions, and even gained IQ points. Why? "We made a comprehensive analysis of these patients' medical data to find out any common feature in the treatments prescribed to them by their GP", explains Valentina Mancini. Two observations caught their attention.

The first is the prescription of small, regular doses of SSRIs - a drug that increases the levels of serotonin, a neurotransmitter involved in the regulation of behaviour - in late childhood and throughout adolescence. "These drugs increase neurogenesis and act on synaptic plasticity. They are prescribed today to reduce anxiety and depressive symptoms", explains the Geneva researcher. And the younger the patients received this treatment, at around 10-12 years of age, the more the frontal lobe and the hippocampus - and therefore the intellectual capacities - were preserved from deterioration caused by the psychotic illness. The second observation is that a neuroleptic drug - prescribed in small doses to control psychotic symptoms such as hallucinations or delusions - also seems to have a positive effect if added to SSRIs during adolescence. "These two medications, especially when combined, have thus preserved the anatomical structure of the brain affected by the degradation responsible for the decline in intellectual capacity", remarks Stéphan Eliez.

A promising discovery for the future of people at risk of psychosis

This study provides for the first time an indication of a neuroprotective preventive treatment for the development and preservation of IQ. "It should be stressed that too great a deterioration of intellectual skills progressively leads to a very problematic psychosocial dependence. Here, we could succeed in protecting this population", notes Stéphan Eliez.

Once the results of this study are confirmed, the effect of SSRIs could be tested on other types of patients and possibly prescribed preventively to people at risk of intellectual deterioration, such as individuals with other genetic syndromes like Fragile X or Down's syndrome, or children of schizophrenic parents. "We also want to investigate whether the 3% to 4% of adolescents in the general population who develop psychotic symptoms would see this risk reduced by taking this drug", continues Valentina Mancini.

The Geneva team will now compare the results obtained from their research cohort with international databases in order to confirm the neuroprotective role induced by these treatments prescribed at the end of childhood, adolescence being the critical phase for the onset of psychotic diseases.

 

Curtin study finds WA's natural 'museums of biodiversity' at risk

CURTIN UNIVERSITY

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IMAGE: A BIODIVERSE BIF IN THE MID WEST view more 

CREDIT: CURTIN UNIVERSITY

Up to three quarters of the biodiversity living on Western Australia's iconic ironstone mountains in the State's Mid West (known as Banded Iron Formations) could be difficult or impossible to return quickly to its previous state after the landscape has been mined, a Curtin University study has found.

The research published in Ecology and Evolution, discovered that the plant ecosystems are well-adapted to the characteristics of the region's ancient and nutrient-poor soils - and that the very different features of mined landscapes mean many native species are unlikely to be returned by rehabilitation.

Lead researcher Dr Adam Cross from Curtin's School of Molecular and Life Sciences said the elevation and different habitats offered by Banded Iron Formations (BIF) in an otherwise dry, mostly flat landscape, make them a sponge for biodiversity - but that their iron-rich rock made them increasingly attractive to iron-ore miners.

"Unfortunately, the chemical characteristics of some tailings and other by-products produced by mines can be more similar to material on the moon than to the ancient, highly-weathered soils of BIF, and this presents a really challenging, hostile environment for many native plant species," Dr Cross said.

The Mid West region is known for its BIF ranges, which Dr Cross describes as stunning natural 'museums', that host much of the regional florist biodiversity. He said almost every plant species from the surrounding landscape can be found on them - as well as some unique species found nowhere else.

"These collections of species have accumulated over very long periods of time, and the increased pressure to mine BIF is putting the biodiversity at risk. Once BIF are gone, that's it - we cannot recreate these iconic landforms, and our study suggests that, even if we could, the post-mining environment likely wouldn't support many of the species that used to call them home."

"BIF harbour such biodiversity because in periods where the climate has been hotter and drier, their rocky, complex soils offered a cooler, wetter refuge for many species that were unable to survive in the surrounding landscape.

"With climate change suggesting a hotter, drier outlook for the Mid West region in future decades, it is increasingly important that we preserve and conserve remaining BIF habitats and the species growing on them."

The research team looked at 538 plant species in an 82,000 hectare area in WA's Mid West, assessing their growth on different soil types across the region and examining their potential tolerance to the chemical characteristics of mined materials.

Although many species were adapted to the acidic, nutrient-poor soils of BIF, the team found at least some were tolerant of a wide range of soil types and might be used as 'pioneers' to help kick-start vegetation recovery in rehabilitation.

Dr Cross said more studies were needed to find ways to rapidly change the chemical characteristics of post-mining soils to speed up rehabilitation, and preserve the area's biodiversity.

"The mining industry needs to consider the soil properties of landforms requiring rehabilitation or ecological restoration, and the implications for vegetation establishment and plant community development, at the very earliest stages of planning or environmental impact assessment," Dr Cross said.

"Ecosystems are extremely complex; we need to recognise, appreciate and learn from this complexity when we are attempting to return biodiversity to areas that have been impacted by mining.

"We need to reach a happy medium between development and conservation to effectively continue mining in these areas, while preserving our incredible natural resources."

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The research was funded by The Centre for Mine Site Restoration at Curtin University.

The full paper Calcicole-calcifuge plant strategies limit restoration potential in a regional semi-arid Flora can be found online here: https://onlinelibrary.wiley.com/doi/10.1002/ece3.7544.

 

Newly identified atmospheric circulation enhances heatwaves and wildfires around the Arctic

HOKKAIDO UNIVERSITY

Research News

 

IMAGE: THE RELATIONSHIPS AMONG CAW, HEATWAVES, WILDFIRES, AND POLLUTION. ANOMALOUS ANTICYCLONES CHARACTERIZE THE ATMOSPHERIC CIRCULATION THAT DEVELOPS CONCOMITANTLY OVER THE THREE REMOTE REGIONS AROUND THE SUMMERTIME ARCTIC (JULY AND AUGUST). THE... view more 

CREDIT: TEPPEI J. YASUNARI, ET AL. ENVIRONMENTAL RESEARCH LETTERS. MAY 17, 2021.

Scientists have uncovered a summertime climate pattern in and around the Arctic that could drive co-occurrences of European heatwaves and large-scale wildfires with air pollution over Siberia and subpolar North America.

In recent years in summer, there have often been extremely high temperatures over Europe, including heatwaves and active wildfires in and around the Arctic such as Siberia and subpolar North America (Alaska and Canada), which have caused widespread air pollution. For instance, in July 2019, significant Alaskan wildfires were detected by satellites. The recent unusual climate phenomena are of immense concern to many people living in these regions.

A team of scientists from Japan, South Korea, and the USA, including Hokkaido University's Assistant Professor Teppei J. Yasunari, have revealed relationships among wildfires, aerosols (air pollution), and climate patterns in and around the Arctic. They have published their discoveries in the journal Environmental Research Letters. Involved in this study were Professor Hisashi Nakamura, The University of Tokyo, Japan; Dr. Nakbin Choi and Professor Myong-In Lee, Ulsan National Institute of Science and Technology, Republic of Korea; and Professor Yoshihiro Tachibana, Mie University, Japan, and two scientists from the Goddard Space Flight Center, National Aeronautics and Space Administration (NASA), USA.

"Wildfires lead to extensive air pollution, primarily in the form of inhalable particulate matter with diameters of 2.5 micrometers or smaller (PM2.5). Arctic hazes during winter and spring are typical phenomena due to aerosols existing in the Arctic. In our scientific field, it is also known that deposition of light-absorbing aerosols onto snow surfaces can induce the so-called snow darkening effect, contributing to accelerated snow melting. For these reasons, long-term assessments of PM2.5 and aerosols in the Arctic and surrounding regions are required," said Yasunari.

For their investigations, the scientists used the MERRA-2 (Modern-Era Retrospective analysis for Research and Applications, version 2) dataset and fire data by satellite, both produced by NASA, focusing on the recent period from 2003 to 2017. They assessed comprehensive air pollution (i.e., PM2.5) in the Arctic for as long as the past 15 years, seeking to clarify the relationships between variations in PM2.5 and aerosols, wildfires, and the relevant climate patterns.

"We found 13 out of the 20 months with highest PM2.5 in the Arctic during the 15 year period were in summer. The elevated PM2.5 levels were highly correlated with relatively higher organic carbon aerosol concentrations, implying active wildfires. We concluded that the summertime wildfires contributed to those months with exceptionally high PM2.5 in the Arctic. In those months, the wildfires likely occurred under extremely warm and dry conditions. Those were due to concomitantly persistent or developed high-pressure systems over Europe, Siberia, and subpolar North America, namely, Alaska and Canada," explained Yasunari.

The scientists named this climate (atmospheric circulation) pattern, the circum-Arctic wave (CAW) pattern, as a driver for enhancing the co-occurrence of heatwaves in Europe and wildfires in Siberia and subpolar North America. In fact, the CAW-like pattern was also seen in the early summer of 2019, which was outside the period of the MERRA-2 analyses.

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Joint release by Hokkaido University, Research Center for Advanced Science and Technology, the University of Tokyo, Ulsan National Institute of Science and Technology, and Mie University.

 

Safe distance: How to make sure our outdoor activities don't harm wildlife

PENSOFT PUBLISHERS

Research News

 

IMAGE: AN INFOGRAPHIC ILLUSTRATES THE SAFE DISTANCE BETWEEN HUMANS AND DIFFERENT TYPES OF ANIMALS. view more 

CREDIT: SARAH MARKES/WCS

Spending time outdoors is good for a person's body and soul, but how good is it for the wildlife around us?

Outdoor recreation has become a popular activity, especially in the midst of a pandemic, where access to indoor activities might be limited. Long known to have negative behavioural and physiological effects on wildlife, outdoor recreation is one of the biggest threats to protected areas. Human disturbance to animal habitats can lower their survival and reproduction rates, and ultimately shrink populations or eradicate them from areas where they would otherwise thrive. Still, park planners and natural resource managers often can't find clear recommendations on how to limit these impacts.

A new scholarly article in the open-access, peer-reviewed journal Nature Conservation from researchers at the Wildlife Conservation Society looked at nearly 40 years of research on recreation impacts on wildlife to try to find the point where recreation starts to impact the wildlife around us. Knowing when and to what extent a species is being disturbed can ultimately allow for more informed and effective management decisions and increase the chances of its successful conservation.

The researchers found that the impact or uncomfortable distance to humans, vehicles or trails for shorebirds and songbirds was as short as 100 meters or even less, whereas for hawks and eagles it was greater than 400 meters. For mammals, it varied even more widely, with an impact threshold of 50 meters for medium-sized rodents. Large ungulates - like elk - would rather have to stay 500 to 1,000 meters away from people.

While human disturbance thresholds can vary widely, large buffer zones around human activities and controlled visitation limits should always be considered during planning and maintenance of parks and protected areas. Based on their findings, the authors recommend that human activities should be considered to be impacting wildlife at least 250 metres away. Further, they call for future research to explicitly identify points where recreation begins or ends to impact wildlife.

Original source: Dertien JS, Larson CL, Reed SE (2021) Recreation effects on wildlife: a review of potential quantitative thresholds. Nature Conservation 44: 51-68. https://doi.org/10.3897/natureconservation.44.63270

CAPTION

Human recreation and wildlife often overlap. Here an American black bear and hikers use the same trail hours apart in Sonoma County, California, USA

CREDIT

Wildlife Conservation Society

 

Sick bats also employ 'social distancing' which prevents the outbreak of epidemics

New study from Tel Aviv University reveals that bats also resort to isolation which can assist in preventing mass contagion

TEL-AVIV UNIVERSITY

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IMAGE: IMAGES OF BATS. view more 

CREDIT: YUVAL BARKAI.

The Covid-19 pandemic has introduced us to expressions like 'lockdown', 'isolation' and 'social distancing', which became part of social conduct all over the world. Now it appears that bats also maintain social distancing which might help prevent the spread of contagious diseases in their colonies. In a new study published in Annals of the New York Academy of Science, researchers from Tel Aviv University demonstrate that sick bats, just like ill humans, prefer to stay away from their communities, probably as a means for recovery, and possibly also as a measure for protecting others. The study was conducted by postdoctoral researcher Dr. Kelsey Moreno and PhD candidate Maya Weinberg at the laboratory of Prof. Yossi Yovel, Head of the Sagol School of Neuroscience and a researcher at School of Zoology at the George S. wise Faculty of Life Sciences.

The study monitored two colonies of Egyptian fruit bats - one living in an enclosure and the other in its natural environment. To examine the behavior of bats when they get sick, the researchers injected several bats in each group with a bacteria-like protein, thereby stimulating their immune response without generating any real danger to the bats. Tests revealed symptoms such as a high fever, fatigue and weight loss, and the 'ill' bats' behavior was tracked with GPS.

The researchers discovered that the 'sick' bats chose to keep away from the colony. In the first group, they left the bat cluster of their own accord and kept their distance. In the second group the 'ill' bats likewise moved away from the other bats in the colony, and also stayed in the colony and did not go out in search of food for two successive nights.

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Images of bats.

CREDIT

Yuval Barkai.

Research student Maya Weinberg explains that this social distancing behavior is probably caused by the need to conserve energy - by avoiding the energy-consuming social interactions in the group. Weinberg emphasizes, however, that this behavior can also protect the group and prevent the pathogen from spreading within the colony. Moreover, the fact that sick bats don't leave the cave, prevents the disease from spreading to other colonies. "The bats' choice to stay away from the group is highly unusual for these animals. Normally these bats are extremely social creatures, living in caves in very crowded conditions," says Weinberg. "In fact, the 'sick' bats' behavior is very reminiscent of our own during recovery from an illness. Just as we prefer to stay home quietly under the blanket when we are ill, sick bats, living in very crowded caves, also seek solitude and peace as they recuperate."

Prof. Yovel adds that the study's findings suggest that the likelihood of bats passing pathogens to humans under regular conditions is very low, because sick bats tend to isolate themselves and stay in the cave. "We observed that during illness bats choose to stay away from the colony and don't leave the cave, and thus avoid mixing with other bats. This suggests that in order to encounter a sick bat, people must actually invade the bats' natural environment or eliminate their habitats. In other words, if we protect them, they will also protect us."

CAPTION

Prof. Yossi Yovel

CREDIT

Tel Aviv University

 

Solar energy-driven sustainable process for synthesis of ethylene glycol from methanol

DALIAN INSTITUTE OF CHEMICAL PHYSICS, CHINESE ACADEMY SCIENCES

Research News

 

IMAGE: DIRECT PHOTOCATALYTIC COUPLING OF METHANOL TO ETHYLENE GLYCOL (EG) IS HIGHLY ATTRACTIVE. THE FIRST METAL OXIDE PHOTOCATALYST, TANTALUM-BASED SEMICONDUCTOR, IS REPORTED FOR PREFERENTIAL ACTIVATION OF C-H BOND WITHIN METHANOL TO... view more 

CREDIT: CHINESE JOURNAL OF CATALYSIS

The photochemistry of the future will spring up human industry without smoke, and bring a brighter civilization based on the utilization of solar energy instead of fossil energy. Photochemistry has been used in controlling many reaction processes, especially for the challenging reactions containing selective C-H activation and C-C coupling in chemical synthesis. It is of great interests that a "dream catalytic reaction" of direct coupling of methanol to ethylene glycol (2CH3OH ? HOCH2CH2OH + H2, denoted as MTEG) could be achieved through the solar energy-driven C-H activation and C-C coupling processes, and this MTEG reaction has not been achieved through thermocatalysis yet.

Ethylene glycol (EG) is an important monomer for the manufacture of polymers (e.g., poly(ethylene terephthalate), PET), and can also be used as antifreeze and fuel additive. The annual production of EG is more than 25 million tons, which is primarily produced from petroleum-derived ethylene industrially. Methanol is a clean platform chemical, which can not only traditionally produced from natural gas and coal, but also has been directly synthesized from biomass and CO2. Thus, the solar energy-driven MTEG route provides an alternative process for sustainable synthesis of EG and H2 from methanol directly with great attractions.

Although direct photocatalytic coupling of methanol to EG is highly attractive, the reported photocatalysts for this reaction are all metal sulfide semiconductors, which may suffer from photocorrosion and have low stability. Thus, the development of non-sul?de photocatalysts for efficient photocatalytic coupling of methanol to EG and H2 with high stability is urgent but extremely challenging.

Recently, a research team led by Prof. Ye Wang from Xiamen University and Yanshan University, China reported the first metal oxide photocatalyst, tantalum-based semiconductor, for preferential activation of C-H bond within methanol to form hydroxymethyl radical (* CH2OH) and subsequent C-C coupling to EG. Compared with other metal oxide photocatalysts, such as TiO2, ZnO, WO3, Nb2O5, tantalum oxide (Ta2O5) is unique in that it can realize the selective photocatalytic coupling of methanol to EG. The co-catalyst free nitrogen doped tantalum oxide (2%N-Ta2O5) shows an EG formation rate as high as 4.0 mmol/g/h, about 9 times higher than that of Ta2O5, with a selectivity higher than 70%. The high charge separation ability of nitrogen doped tantalum oxide plays a key role in its high activity for EG production. This catalyst also shows excellent stability longer than 160 h, which has not been achieved over the reported metal sulfide photocatalysts. Tantalum-based photocatalyst is an environmentally friendly and highly stable candidate for photocatalytic coupling of methanol to EG. The results were published in Chinese Journal of Catalysis.

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About the Journal

Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top six journals in Applied Chemistry with a current SCI impact factor of 6.146. The Editors-in-Chief are Profs. Can Li and Tao Zhang.

At Elsevier http://www.journals.elsevier.com/chinese-journal-of-catalysis
Manuscript submission https://mc03.manuscriptcentral.com/cjcatal

 

Restored peatlands store carbon and mitigate climate change

ESTONIAN RESEARCH COUNCIL

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IMAGE: VIRU TEST SITE USING THE CANADIAN PEAT MOSS APPLICATION METHOD (RIGHT) AND CONTROL PATCH (LEFT) WHERE NOT USED. view more 

CREDIT: TALLINN UNIVERSITY

Estonia has almost 10,000 ha of peat production land that has lain abandoned since the Soviet era, as well as peatland that is in use at present for peat production but whose resources will be exhausted in the near future. There are also 160,000 ha of peatland that have been drained for forestry. The findings from the research conducted by Tallinn University doctoral student Anna-Helena Purre are able to be put to practical use in planning and carrying out the restoration of peatlands and thereafter in evaluating the success of the restoration. What makes these activities topical is the fact that a lot of attention will be directed to ecological restoration from 2021-2030, which the United Nations has named the UN Decade of Ecosystem Restoration.

The water level in bogs in their natural state is constantly high and the vegetation that grows in them is accustomed to such conditions - the synergy between them storing carbon dioxide from the atmosphere into the peat in these areas. As a result of draining peatlands, the bogs lose their distinctive vegetation and these areas instead become a source of carbon dioxide (CO2). This can be alleviated by ecologically restoring the areas. Purre's thesis examines the vegetation and exchange of carbon dioxide on peatlands where peat was previously produced or that have been drained for forestry. She compares these results to the vegetation and carbon dioxide flow in undisturbed bogs, assessing the success rate of restoration in restored areas in terms of bog structure (abundance of vegetation) and function (storing CO2 in peat or emitting it into the atmosphere). She also investigates the growth of vegetation and the successfulness of restoration in restored peat production areas dependent on the restoration methods used in experimental sites (species of peat mosses and the density of their spreading, plus reprofiling and fertilising of the peat surface) and the characteristics of residual peat in the experimental sites.

Purre concludes that forest drainage areas which were restored 5-10 years before the measurements were similar to undisturbed bogs in terms of structure and function, but at the same time that recovery was slower in peat production areas. "That result was somewhat expected, because in peat production areas, restoration starts with the bare peat surface and then moves towards the ecological community," she explains. "In forestry drainage, on the other hand, the vegetation already exists and begins to develop after restoration from the vegetation being dry and shade tolerant plant communities to more open and wet plant communities." Purre adds that the carbon dioxide sink function of peatland tends to recover more quickly in restored areas, whereas the development of peatland-specific vegetation needs more time. During her research she determined the impact of different methods of peatland restoration for the peat production areas on the success of restoration and assessed the viability of the moss-layer-transfer-technique developed in Canada in Estonian conditions.

The research contributed to the collection of data regarding the CO2 fluxes. Although previously greenhouse gases fluxes have been measured in the Baltic States using the opaque-chamber method, with which it is only possible to assess the amount of CO2 being emitted into the atmosphere through the ecosystem respiration, the data published in this thesis about natural bogs and restored peatlands with forest drainage are the first in the Baltic States to evaluate the entire exchange of CO2 of the ecological community, taking into consideration the amount of CO2 bind via photosynthesis, by measuring this with transparent chambers. "This is very important, since bogs in their natural state mainly store carbon dioxide, slowly bringing down the amount of carbon dioxide in the atmosphere and mitigating climate change," Purre adds. "For this reason, it is important to know when and how this function will be restored on disturbed peatlands that have undergone restoration."

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The doctoral thesis is available in Tallinn University Digital Library ETERA. https://www.etera.ee/zoom/126023/view?page=1&p=separate

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Measurement of carbon dioxide.

CREDIT

Timo Penttilä

 

How do plants hedge their bets?

UNIVERSITY OF CAMBRIDGE

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IMAGE: GENETICALLY IDENTICAL ARABIDOPSIS SEEDLINGS GERMINATING AT VARIABLE TIMES. view more 

CREDIT: KATIE ABLEY

In some environments there is no way for a seed to know for sure when the best time to germinate is.

In spring, cues like light, temperature and water may suggest to seeds that conditions are optimal for germination, but a week later an unpredictable drought or frost could kill the emerging seedlings.

So how does a plant make sure that all of its offspring are not killed at once by an ill-timed environmental stress following germination?

There is evidence that some plant species produce seeds that germinate at different times to hedge their bets against this risk. Many species produce seeds that can enter a dormant state and exist in the soil for several years and some also produce seeds that germinate at different times within a season.

This means that if lethal environmental fluctuations do occur, a fraction of a plant's offspring will survive as seeds, which can go on to germinate at another time.

This variability in germination time can be seen even with genetically identical seeds grown in an identical environment.

In agriculture, the variability in germination time can be a problem when you want to harvest the whole crop at the same time. Instead, farmers have to monitor their crops' maturity, taking measurements from multiple individual plants to estimate when the best time is to harvest.

Scientists at the Sainsbury Laboratory Cambridge University (SLCU) used the model plant, thale cress (Arabidopsis thaliana), to ask: What makes genetically identical seeds germinate at different times?

"We already know that two plant hormones - abscisic acid (ABA) that inhibits germination and gibberellic acid (GA) that promotes germination - interact with each other to control the decision to germinate, but we wanted to know how this interaction creates variability in germination times between seeds", said Dr Katie Abley, researcher at SLCU and joint first author of the research published in eLife.

"By measuring the levels of variability in germination times for hundreds of genetically distinct strains of Arabidopsis, we were able to identify two regions of DNA (genetic loci) that control how variable germination time is. Both loci contain genes that influence how sensitive seeds are to ABA and testing mutants of these genes provided evidence that they regulate variability in germination timing."

Using this new information, the researchers generated a mathematical model of the ABA-GA network to understand how the interactions between ABA and GA could cause a batch of identical seeds to have a range of germination times. They wanted to understand how the network could give rise to different levels of variability in germination time.

"We found that changing ABA sensitivity in the model replicated the experimental germination time distributions that we observed", explained Dr Pau Formosa-Jordan, joint first author and now research group leader at Max Planck Institute for Plant Breeding Research in Cologne, Germany.

"In the model, groups of seeds with higher sensitivity to ABA germinate in a more spread-out way because, upon sowing, each one of these seeds relies on stochastic fluctuations in the ABA-GA network to switch from a non-germination state to a germination state - which is known as a bistable switch behaviour. Yet, seeds with lower sensitivity to ABA more rapidly and synchronously get to the germination state after being sown, without the need for the stochastic fluctuations. Our stochastic model suggests an ABA-GA bistable switch can generate variability in germination times, with the germination time being influenced by stochastic fluctuations in the levels of hormones."

While the researchers expect there to be other genetic and biophysical effects at play that affect variability in germination time, their findings show that this plant trait is genetically controlled and high or low variability in germination times could, therefore, be specifically selected for in crop breeding programmes or to rehabilitate natural areas with highly variable environments.

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Reference

Katie Abley, Pau Formosa-Jordan, Hugo Tavares, Emily Y. T. Chan, Mana Afsharinafar, Ottoline Leyser, James C. W. Locke (2021) An ABA-GA bistable switch can account for natural variation in the variability of Arabidopsis seed germination time, eLife.

DOI: https://doi.org/10.7554/eLife.59485

Funding

This research was supported by the Gatsby Charitable Foundation.

 

Clinical-level emotional/behavioral problems in schoolchildren during the lockdown

SHINSHU UNIVERSITY

Research News

 

Efforts to contain the novel coronavirus have caused lockdowns and school closures around the world. These efforts and policies have unfortunately cut off many children from valuable resources such as the opportunity for exercise, access to clean water and food, learning, and socialization. Therefore, the effects on mental health and behavior may be found not just in adults but children. However, studies published thus far have been limited to elucidating the mood of middle school and high school students and the conditions for which mood problems occur remain unclear. Therefore, support and assistance methods to help such students, including younger children remained unclear. To fill this knowledge gap, this study conducted a follow-up study during the time Japan was under a state of emergency and schools were closed in March until May of 2020.

Associate Professor Fumito Takahashi of the Faculty of Education, Shinshu University led this cohort study on elucidating the anguish and problems faced not only by middle school and high school-aged students but also that of grade-schoolers from the first grade and above, until the third year of high school. First graders of elementary-age, who were excluded from the past self-reported surveys due to their inability to articulate their problems on self-report questionnaires, were included in this parent-reported survey, so that the problems in this age group could be understood by teachers, clinicians and policymakers. Not only was the mood of subjects under study such as depression and anxiety, but problematic behaviors such as delinquency, inattention and hyperactivity were successfully elucidated. The study showed that in fact, the inattention and hyperactivity in children grades 1 to 3 were the problems that increased the most during the lockdown.

The cohort study showed that when schools close and there are lockdowns in effect to control the spread of disease, households that have any of the following may need special assistance and support: 1) a household with (a) child(ren) under the age of ten (grades 3 and under), 2) households with low income (under 2 million yen per year) 3) households with children with developmental disabilities.

Dr. Takahashi will continue to research conditions or other support and assistance which allow children to thrive, especially those until adolescence who may have developmental disabilities so that their mental health will not worsen. Such studies aim to make environments in which "characteristics" are turned into "disabilities" fewer and to allocate social resources appropriately for those who experience difficulties so that people of all characteristics can live and thrive.

To realize such a society is not just the work of specialists such as psychiatrists and social workers, but the cooperation of guardians, local residents, pediatricians, nurses, and teachers is crucial. Policies that enable the cooperation of each actor are also important. There remains a lot to do, which means that everyone in any position has a way they can be of help.

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Acknowledgments

This research was supported by KAKENHI 19H04881 from Japan Society for the Promotion of Science (JSPS).

For more information please read: https://acamh.onlinelibrary.wiley.com/doi/10.1111/jcv2.12007