Heatwaves can decrease the biomass of phytoplankton in lakes

Peer-Reviewed Publication

UNIVERSITY OF JYVÄSKYLÄ - JYVÄSKYLÄN YLIOPISTO

 

IMAGE: PHYTOPLANKTON OCCUR MOSTLY IN THE MIXED LAYER, THE DEPTH OF WHICH IS REGULATED BY WEATHER. view more 

CREDIT: SALLA AHONEN / JYU

A recently published study showed that heatwaves reduced the biomass of phytoplankton in a boreal lake. Summertime heatwaves will become more frequent and stronger with climate change and can reduce the biomass of phytoplankton in stratified lakes.

Researchers at the Department of Biological and Environmental Science at the University of Jyväskylä followed the daily biomass of phytoplankton and environmental conditions in a humic lake Jyväsjärvi in central Finland during a summer stratification period.

During that period, warmer and less dense surface water forms a mixed layer above colder and denser water at deeper depths. Phytoplankton occur mostly in the mixed layer, the depth of which is regulated by weather. The depth of the mixed layer controls light and nutrient availability of phytoplankton. Phytoplankton receive less light but more nutrients with an increasing depth of the mixed layer. Phytoplankton needs both light and nutrients for photosynthesis.

“We found that the depth of mixed layer controlled the biomass of phytoplankton. The biomass increased with deepening of the mixed layer and decreased with shallowing of the mixed layer. Phytoplankton is responsible for the primary production in lakes and thus its biomass is the source of energy to other aquatic organisms including fish”, says the lead author of the study Salla Ahonen, a doctoral researcher at the Department of Biological and Environmental Science.

Climatic drives such as wind speed and temperature difference between air and water regulate the depth of the mixed layer. During heatwaves, warm and calm weather reduces the depth of the mixed layer, whereas colder and windy weather deepens the mixed layer. Warming climate will increase heatwaves and thus the conditions that can reduce phytoplankton biomass in lakes.

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JOURNAL

Freshwater Biology

DOI

10.1111/fwb.14048 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Increasing air temperature relative to water temperature makes the mixed layer shallower, reducing phytoplankton biomass in a stratified lake

Study shows that bioprinted artificial skin can be used in cosmetics and drugs testing

The performance of a model obtained in a 3D printer was equivalent to that of the conventional model produced manually. The biomimetic material can be produced on a large scale, reducing animal testing by the cosmetics and pharmaceutical industries

Peer-Reviewed Publication

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO

 

IMAGE: IN EXPERIMENTS CONDUCTED BY SCIENTISTS AT THE UNIVERSITY OF SÃO PAULO, THE PERFORMANCE OF A MODEL OBTAINED IN A 3D PRINTER WAS EQUIVALENT TO THAT OF THE CONVENTIONAL MODEL PRODUCED MANUALLY. view more 

CREDIT: FCF-USP

Bioengineered artificial skin has become an increasingly important and reliable platform for researchers to test the safety and efficacy of drugs and cosmetics. It can be produced on a large scale and is a good substitute for animal testing. The most promising technologies for production of in vitro models include 3D bioprinting. Because it is recent, however, its performance has yet to be sufficiently validated in comparison with traditional manually produced models. This was the main aim of a study conducted by researchers at the University of São Paulo’s School of Pharmaceutical Sciences (FCF-USP) in Brazil. The results, reported in an article published in the journal Bioprinting, confirmed that the artificial skin achieved a similar performance.

In the study supported by FAPESP, the researchers compared the conventional mimetic model based on manual pipetting with extrusion bioprinting, which “allows the in vitro reconstruction of a more relevant and representative model of human skin”, according to the authors of the article.

“Calling the model ‘artificial skin’ makes it sound synthetic, but actually it’s human tissue that closely resembles natural skin and is very suitable for safety and efficacy testing of bioactive compounds,” said Silvya Stuchi Maria-Engler, a professor and researcher at FCF-USP’s Department of Clinical and Toxicological Analysis.

Quality control and performance assessment standards established by international institutions such as the Organization for Economic Cooperation and Development (OECD) were used as validation criteria. “The first was tissue morphology, which should be representative of human skin in vivo, with a stratified epidermis containing four layers: stratum basale, spinosum, granulosum and corneum. This means that in vitro reconstructed skin has the same functions as natural skin, which contains a selective barrier against the external medium for protection against chemical stressors [pollutants and topically applied products] and physical stressors [sunlight], while also retaining water,” said Denisse Esther Mallaupoma Camarena, co-first author of the article and a postdoctoral fellow at FCF-USP.

The next step was to assess the performance of the bioprinted skin as a barrier. Like natural skin, artificial skin should be able to prevent the penetration of detergents that cause irritation. To test this function, the researchers exposed the model to sodium dodecyl sulfate (SDS), a detergent that causes skin irritation, at different concentrations for 18 hours.

The last validation test entailed topical application of reference chemicals classified as irritants (such as acids, for example) or non-irritants (physiological solutions). The results showed the histology and cytoarchitecture of both in vitro reconstructed skin models to be consistent with internationally validated epidermic models. The quality of the bioprinted skin was as good as that of the manually reconstructed skin. Both responded equally well to irritants and distinguished between these and non-irritants.

“These findings prove that our bioprinted skin can be used instead of the Draize test, an acute toxicity test that applies the substance directly to rabbit skin. Besides the avoidance of animal testing, it’s less subject to human error and variability in the responses obtained by the cosmetics industry,” said Julia de Toledo Bagatin, first author of the article and a PhD candidate at FCF-USP.

“Dissemination of part of the methods developed will help increase the use of alternatives to animal testing by the cosmetics industry, reinforcing our commitment to the cause,” said Juliana Lago, penultimate author of the article and scientific manager of Natura, a major Brazilian cosmetics company. Natura supported the study by funding part of the development of the bioprinter used to make the reconstructed skin.

“Basic science done by academia produced the knowledge that served as a foundation for this project. The business-university partnership enabled us to accelerate application of this knowledge in the tissue reconstruction project and automation via bioprinting, all of which is important to our company.”

More reliable bioprinters

Although the main results of the study show that bioprinted skin can be used as a platform to test irritation in the laboratory, the researchers note the need for caution in using bioprinters. “They produce mimetic tissue by cell dispersion using a needle or conical nozzle, and depending on the system chosen, there may be cellular response alterations in the in vitro irritation test,” Maria-Engler said. “Bioprinting is now being used in many fields, so it’s extremely important to acknowledge that the dispersion system chosen can damage the reliability of the tests by leading to altered responses, such as increased inflammation.”

The researchers plan to bioprint more complex models comprising epidermis, dermis and hypodermis with representative human skin cells. This will move the model closer to reality and produce more biologically relevant responses in safety and efficacy testing of products for topical use.

About São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at www.fapesp.br/en and visit FAPESP news agency at www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe

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JOURNAL

Bioprinting

DOI

10.1016/j.bprint.2022.e00251 

ARTICLE TITLE

Bioprinted and manual human epidermis production: A compared performance for skin irritation tests

First report of rare cat discovered on Mt. Everest

New scientific finding marks the first documented discovery of Pallas’s Cat on the world’s highest mountain

Peer-Reviewed Publication

WILDLIFE CONSERVATION SOCIETY

 

IMAGE: FINDINGS FROM A NEW PAPER PUBLISHED IN CAT NEWS HAVE IDENTIFIED THE FIRST EVER REPORT OF PALLAS’S CAT ON MOUNT EVEREST, IN THE SAGARMATHA NATIONAL PARK IN NEPAL view more 

CREDIT: JULIE LARSEN/MAHER/WCS

Findings from a new paper published in Cat News have identified the first ever report of Pallas’s cat on Mount Everest, in the Sagarmatha National Park in Nepal. This groundbreaking finding is a result of the 2019 National Geographic and Rolex Perpetual Planet Everest Expedition, the most comprehensive single scientific expedition to the mountain in history. 

From April 7 to May 2, 2019, Dr. Tracie Seimon of Wildlife Conservation Society’s Zoological Health Program, based at the Bronx Zoo, co-led the Perpetual Planet Everest Expedition biology field team of scientists who collected environmental samples from two locations 6 km (3.7 miles) apart at 5,110 and 5,190 m (16,765 and 17,027 ft) elevation above sea level along Sagarmatha National Park on Mount Everest’s Southern Flank.  

“It is phenomenal to discover proof of this rare and remarkable species at the top of the world,” said Dr. Seimon. “The nearly four-week journey was extremely rewarding not just for our team but for the larger scientific community. The discovery of Pallas’s cat on Everest illuminates the rich biodiversity of this remote high-alpine ecosystem and extends the known range of this species to eastern Nepal.”

The DNA analysis of scat samples collected from both sites confirmed two Pallas’s cats inhabit Mount Everest and overlap in territory with red fox. The researchers found evidence of pika and mountain weasel DNA in the samples, an important food source for Pallas’s cat. These findings also add a new species to the list of known mammals in Sagarmatha National Park, a heavily visited and protected World Heritage site.

“This is a unique discovery not only in terms of science but also conservation as this population of Pallas’s cat is legally protected under CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora),” said National Geographic Explorer and co-author of the paper, Dr. Anton Seimon. “We hope that the confirmation of this new charismatic species will raise awareness of and education about the diversity of species at this iconic World Heritage Site.”

The number of tourists visiting Sagarmatha National Park and Mount Everest has been dramatically increasing, from just a few thousand in the 1970s to over fifty thousand in 2019. It is notable that Pallas’s cat went undetected in this park until 2019, and the new study demonstrates how conservation genetics and environmental sampling can be utilized as a powerful approach to discover and study cryptic and elusive species like Pallas’s cat. 

Future research combining camera trap surveys and collection of additional scat samples would help to better define the Pallas’s cat population, range, density, and their diet in Sagarmatha National Park. 

“The groundbreaking 2019 Perpetual Planet Everest Expedition continues to be extremely valuable to better understand the most iconic environment on our planet,” said Nicole Alexiev, Vice President of Science and Innovation Programs at National Geographic Society. “These results are a perfect illustration of why this work is important and a cornerstone of our partnership with Rolex to study and explore Earth’s critical life support systems.” 

From April to May 2019, an international, multidisciplinary team of scientists conducted the most comprehensive single scientific expedition to Mt. Everest in the Khumbu Region of Nepal as part of National Geographic and Rolex’s Perpetual Planet Expeditions partnership. Team members from eight countries, including 17 Nepalese researchers conducted trailblazing research in five areas of science that are critical to understanding environmental changes and their impacts: biology, glaciology, meteorology, geology and mapping. To learn more visit: https://www.nationalgeographic.com/environment/topic/perpetual-planet 

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METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

First report of Pallas’s cat in Sagarmatha National Park - Mount Everest Region, Nepal

ARTICLE PUBLICATION DATE

25-Jan-2023

Animals: Cat-egorising play and genuine fighting in cats

Peer-Reviewed Publication

SCIENTIFIC REPORTS

The behaviour of cat interactions has been categorised into playful, aggressive and intermediate groups that may help owners distinguish between play and genuine fighting. The study, published in Scientific Reports, suggests that cats may engage in a mixture of playful and aggressive behaviours, which could escalate into a fight if not managed by the owner.

Noema Gajdoš‑Kmecová and colleagues evaluated 105 video clips sourced from YouTube and directly from cat owners of interactions between 210 cats. Based on initial observations of the cats, the authors assembled six observable behaviour categories including wrestling, chasing and vocalisation, which they then used to assess the remaining cats. Cats were grouped based on the frequency and duration of the six behaviours. Separately, four of the authors reviewed the same videos and came up with three groups to define the interactions between cats: ‘playful’ (friendly interactions); ‘agonistic’ (aggressive interactions); or a third category, ‘intermediate’ (a mixture of both playful and aggressive behaviour).

More than a half of the cats (56.2% or 118 cats) were described by the authors as playful in their interaction, 28.6% (60 cats) were labelled as agonistic, and 15.2% (32 cats) were labelled as intermediate.

When comparing the cat behaviour groups with the three interaction groupings defined by the authors, they found that wrestling behaviour between cats was most closely associated with the playful group, while vocalization and chasing were associated with the agonistic group. The intermediate group, while observed as having characteristics of both, was more closely related to the playful group than the agonistic group. The intermediate group showed prolonged exchanges of behaviours such as laying on their back with their belly upwards, pouncing, stalking, and approaching and grooming each other.

The authors suggest that this combination of playful and aggressive behaviours may reflect a short-term disagreement in social behaviour between the cats, rather than a break-down in the relationship. The authors suggest that identifying potential tension between cats may help owners manage the relationship to avoid escalation and the need for separation.

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Article details

An ethological analysis of close-contact inter-cat interactions determining if cats are playing, fighting, or something in between

DOI: 10.1038/s41598-022-26121-1

Please link to the article in online versions of your report (the URL will go live after the embargo ends):  https://www.nature.com/articles/s41598-022-26121-1

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JOURNAL

Scientific Reports

DOI

10.1038/s41598-022-26121-1 

What you do in your garden to help pollinators work

Peer-Reviewed Publication

LUND UNIVERSITY

Have you made adjustments to your garden to make it more welcoming for pollinators? If so, you have probably made a valuable contribution, according to a new study from Lund University. The researchers evaluated the national ‘Operation: Save the Bees’ campaign, and their results indicate that what private individuals do in their gardens really can make a positive difference.

The fact that pollinating insects are crucial for the functioning of ecosystems and food supply is well known. However, many pollinating species are endangered or in decline.

In 2018, The Swedish Society for Nature Conservation launched a campaign to save bees and other pollinators, aiming to get the public involved by creating more favorable environments in private gardens. The actions that were encouraged were to create a meadow, plant flowers or set up a bee hotel. Around 11,000 Swedes responded to the call, and now researchers from Lund University have evaluated the measures.

“We wanted to investigate measures that the public themselves chose to implement in their garden, and how these can be the most efficient”, says Anna Persson, researcher at Lund University and one of the people behind the study.

Older and species-rich environments best

The result show that the greatest positive effect on the number of pollinating insects was if you had a meadow with a higher number of flowering species in your garden. As for flower plantings, it was favorable if they were older and also covered a larger area. Bee hotels, in turn, were more often inhabited if they were located in flower-rich gardens, if they were older, and if the nest holes were a maximum of one centimeter in diameter.

Anna Persson believes the study is useful when giving the right instructions to those who want to make an effort for pollinators on their own.

“For example, we can show that it will pay off to create large and species-rich meadows and flower plantings, and that it is important not to give up after a few years, because the measures improve over time. This should be emphasized in future campaigns”, she says.

She also hopes that the results can inspire more people to adapt their own green space so that it becomes more favorable for insects. Gardens often cover about thirty percent of the land area in cities and towns, so garden owners as a group have the potential to contribute to urban biodiversity to a relatively high extent.

It is important to invest in the right measures

“However, the right measures must be taken. Our results can be used when giving advice on what actually makes a difference”, says Anna Persson.

The study was carried out through so-called citizen science, where private individuals reported what measures they took in their gardens, and how many insects they saw. 3,758 people responded to the researchers' survey.

A third of Sweden's bee species are currently red-listed, which means they are endangered.

“The situation for bees and other pollinators shows that measures to help them are important. It's great that the campaign has attracted so much attention, and that citizen science can continue to contribute to new knowledge”, says Karin Lexén, Secretary General of The Swedish Society for Nature Conservation.

Citizen research and uncertainty

Since the researchers collected the data via peoples’ own estimates, there is a great deal of uncertainty in each individual data point, says Anna Persson, but adds that one can still be confident in the results given that so many responses were received.

To verify how well the rough estimate of the number of pollinators worked, the researchers also asked the participants to count the number of flower-visiting insects during ten minutes on a sunny day in July. Just over 350 responses were received, and the results were well in line with the estimated quantities.

“Our study could be affected by so-called "expectation bias". This means that people who have taken measures and created more species-rich gardens also expect to see more insects, and thus risk reporting too high a number”, concludes Anna Persson.

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JOURNAL

Frontiers in Sustainable Cities

DOI

10.3389/frsc.2022.1099100 

ARTICLE TITLE

Citizen science initiatives increase pollinator activity in private gardens and green spaces

Fear of public places is common in adults with epilepsy

Peer-Reviewed Publication

ATRIUM HEALTH WAKE FOREST BAPTIST

WINSTON-SALEM, N.C. – Jan. 26, 2023 – About 5.1 million people in the U.S. have a history of epilepsy, which causes repeated seizures. According to the Epilepsy Foundation, epilepsy is the fourth most common neurological disorder. While current research has shown an increase in anxiety and depression among people with epilepsy, little is known about this population and agoraphobia, an anxiety disorder that involves the fear of being in a public place or in a situation that might cause panic or embarrassment.

However, a recent study from Heidi Munger Clary, M.D., M.P.H., associate professor of neurology at Wake Forest University School of Medicine, shows that phobic and agoraphobic symptoms are common and associated with poor quality of life in people with epilepsy.

The study appears online in Epilepsy Research.

“We know that agoraphobia can lead to delays in patient care because of a reluctance to go out in public, which includes appointments with health care providers,” said Munger Clary, the study’s principal investigator. “So, this is an area that needs more attention in clinical practice.”

In the study, researchers conducted a cross-sectional analysis of baseline clinical data from a neuropsychology registry cohort study. Researchers analyzed a diverse sample of 420 adults, ages 18 to 75, with epilepsy who underwent neuropsychological evaluation over a 14-year period at Columbia University Medical Center in New York.

“More than one-third of the participants reported significant phobic/agoraphobic symptoms,” Munger Clary said. “We also found that phobic/agoraphobic symptoms, along with depression symptoms, were independently associated with poor quality of life, but generalized anxiety symptoms were not.”

According to Munger Clary, because phobic/agoraphobic symptoms are not routinely assessed by clinicians, the findings may suggest a need for future studies to develop more comprehensive screeners for psychiatric comorbidity in epilepsy.

“Symptoms of agoraphobia do not fully overlap with generalized anxiety or depression symptoms that are often screened in routine practice,” Munger Clary said. “Providers might want to consider more robust symptom screening methods to identify and better assist these patients. This may be important to improve health equity, given other key study findings that show those with lower education and non-white race/ethnicity had increased odds of significant phobic/agoraphobic symptoms.”

This work was supported in part by the National Institutes of Health under grants R01 NS035140, KM1 CA156709, UL1 TR001420 and 5KL2TR001421-04.

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JOURNAL

Epilepsy Research

DOI

10.1016/j.eplepsyres.2023.107092 

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Afraid to go out: Poor quality of life with phobic anxiety in a large cross-sectional adult epilepsy center sample

ARTICLE PUBLICATION DATE

25-Jan-2023

Deciphering the inner workings of a bacterium

Holistic understanding of metabolism allows prediction of growth of a key environmental microbe

Peer-Reviewed Publication

UNIVERSITY OF OLDENBURG

 

IMAGE: A ROBOT PUNCHES OUT PINHEAD-SIZED PIECES FROM A GEL LAYER. THE NARROW BLUE BANDS CONTAIN PROTEINS FROM A BACTERIAL CULTURE. SUBSEQUENTLY, THE PROTEINS CONTAINED IN THE TINY GEL PIECES WILL BE SORTED IN GREATER DETAIL. view more 

CREDIT: UNIVERSITY OF OLDENBURG/MOHSSEN ASSANIMOGHADDAM

A team led by University of Oldenburg microbiologist Prof. Dr. Ralf Rabus and his PhD student Patrick Becker has gained deep insights into the cellular mechanisms of a common environmental bacterium. The researchers examined the entire metabolic network of the bacterial strain Aromatoleum aromaticum EbN1T and used the results to develop a metabolic model with which they can predict the growth of these microbes under diverse environmental conditions.

As the researchers report in the science journal mSystems, their analysis revealed certain unexpected mechanisms that apparently enable these bacteria to adapt to rapidly changing environmental conditions. The results of the study are important for ecosystems research, a field where the Aromatoleum strain, as a representative of a key group of environmental bacteria, can serve as a model organism, and could also be of interest in the remediation of contaminated sites and for biotechnological applications.

The studied bacterial strain specialises in the utilisation of organic substances that are difficult to break down and is generally found in soil and in aquatic sediments. The microbes thrive in a variety of conditions including oxygen, low-oxygen and oxygen-free layers, and are also extremely versatile in terms of nutrient intake. They metabolise more than 40 different organic compounds including highly stable, naturally occurring substances such as components of lignin, the main structural material found in wood, and long-lived pollutants and components of petroleum.

A microbe with special abilities

In particular, substances with a benzene ring composed of six carbon atoms, known as aromatic compounds, can be biodegraded by these microbes – with or without the aid of oxygen. Due to these abilities, Aromatoleum plays an important environmental role in the complete degradation of organic compounds in soil and sediments to carbon dioxide – a process which is also useful in biological soil remediation.

The aim of the current study was to gain a holistic understanding of the functioning of this unicellular organism. To this end, the researchers cultivated the microbes under both oxic and anoxic conditions – i.e. with and without oxygen – using five different nutrient substrates. For each of these ten different growth conditions, they grew 25 cultures and then examined the various samples using molecular biology methods (technical term: multi-omics) which enable simultaneous analysis of all the transcribed genes in a cell, all the proteins produced and all its metabolic products.

Systems biology approach

"With this systems biology approach, you gain a deep understanding of all the inner workings of an organism," explains Rabus, who heads the General and Molecular Microbiology research group at the University of Oldenburg's Institute for Chemistry and Biology of the Marine Environment (ICBM). "You break down the bacterium into its individual components and then you can put them back together – in a model that predicts how fast a culture will grow and how much biomass it will produce."

Through their meticulous work, the researchers obtained a comprehensive understanding of the metabolic reactions of this bacterial strain. They found that around 200 genes are involved in the degradation processes and determined which enzymes break down the substances added as nutrients and via which intermediates the various nutrients are decomposed. The scientists incorporated their findings about the metabolic network into a growth model, and demonstrated that the model predictions largely corresponded to the measured data.

"We can now describe the organism with a level of precision that has so far only been possible with very few other bacteria," says Rabus. This holistic view of the bacteria's cellular inner workings forms the basis for a better understanding of the interactions between the analysed strain (and related bacteria) and their biotic and abiotic environment, he adds, and can also help scientists to better predict the activity of these unicellular organisms in polluted soils and thus, for example, determine the optimal conditions for the remediation of a contaminated site.

A surprising waste of energy

By combining different methods, the team was able to uncover unexpected mechanisms in the metabolism of these bacteria. Much to the researchers' surprise, it emerged that the microbe produces several enzymes which they cannot use under the given growth conditions – which at first glance would seem to be a superfluous expenditure of energy. "Usually the bacterial cells detect whether oxygen is present in their environment and then, via specific mechanisms, activate only the nutrient-specific metabolic pathway with the corresponding enzymes," Rabus explains.

But with some substrates, the microbe produced all the enzymes for aerobic and anaerobic degradation pathways regardless of oxygen levels – even though some of these enzymes were entirely superfluous. Rabus suspects that this apparent waste is in fact a strategy for surviving in an unstable environment: "Even if oxygen levels suddenly fluctuate – which is often the case in natural environments – Aromatoleum remains flexible and can utilise this nutrient and produce energy as required," the microbiologist explains, adding that so far, no other bacteria are known to use such a mechanism.

The study was conducted by a large interdisciplinary team which included researchers from the University of Oldenburg as well as scientists from a team led by Prof. Dr Dietmar Schomburg at the Technische Universität Braunschweig and a team led by PD Dr Meina Neumann-Schaal at the Leibniz Institute DSMZ in Braunschweig. The lead authors were Patrick Becker and Dr Daniel Wünsch from the University of Oldenburg and Dr Sarah Kirstein from the TU Braunschweig.

The bacterium Aromatoleum aromaticum EbN1T (outlined in black, at the bottom) interacts with the biotic and abiotic environment in many ways: anthropogenic input, the activity of other microorganisms and processes in nature generate different organic substances (different colored dots), which the bacterium uses as food. At the same time, these substances are also utilized by other microorganisms (food competition). The metabolic network within the bacterial cell converts and degrades the substances via different pathways (left). The cell in turn produces building materials such as DNA, proteins, sugar compounds or lipids (right), which it needs for growth. Depending on environmental conditions, the cell obtains energy with the help of oxygen or nitrate (NO3-) - shown on the far left of the image.

CREDIT

Ralf Rabus and Patrick Becker/University of OldenburgJOURNAL

mSystems

DOI

10.1128/msystems.00685-22 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Cells

ARTICLE TITLE

Systems Biology of Aromatic Compound Catabolism in Facultative Anaerobic Aromatoleum aromaticum EbN1T

Health impact of chemicals in plastics is handed down two generations

UC Riverside mouse study finds paternal exposure to phthalates increases risk of metabolic diseases in progeny

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - RIVERSIDE

RIVERSIDE, Calif. -- Fathers exposed to chemicals in plastics can affect the metabolic health of their offspring for two generations, a University of California, Riverside, mouse study reports.

Plastics, which are now ubiquitous, contain endocrine disrupting chemicals, or EDCs, that have been linked to increased risk of many chronic diseases; parental exposure to EDCs, for example, has been shown to cause metabolic disorders, including obesity and diabetes, in the offspring.

Most studies have focused on the impact of maternal EDC exposure on the offspring’s health. The current study, published in the journal Environment International, focused on the effects of paternal EDC exposure.

Led by Changcheng Zhou, a professor of biomedical sciences in the School of Medicine, the researchers investigated the impact of paternal exposure to a phthalate called dicyclohexyl phthalate, or DCHP, on the metabolic health of first generation (F1) and second generation (F2) offspring in mice. Phthalates are chemicals used to make plastics more durable.

The researchers found that paternal DCHP exposure for four weeks led to high insulin resistance and impaired insulin signaling in F1 offspring. The same effect, but weaker, was seen in F2 offspring.

“We found paternal exposure to endocrine disrupting phthalates may have intergenerational and transgenerational adverse effects on the metabolic health of their offspring,” Zhou said. “To the best of our knowledge, our study is the first to demonstrate this.”

In the case of paternal exposure in the study, intergenerational effects are changes that occur due to direct exposure to a stressor, such as exposure to DCHP of fathers (F0 generation) and his developing sperm (F1 generation). Transgenerational effects are changes passed down to offspring that are not directly exposed to the stressor (for example, F2 generation).

Zhou’s team focused on sperm, specifically, its small-RNA molecules that are responsible for passing information down generations. The researchers used “PANDORA-seq method,” an innovative method that showed DCHP exposure can lead to small-RNA changes in sperm. These changes are undetected by traditional RNA-sequencing methods, which lack the comprehensive overview of the small-RNA profile that PANDORA-seq provides. 

The study used only F1 males to breed with unexposed female mice to generate F2 offspring. The team found that paternal DCHP exposure induced metabolic disorders, such as impaired glucose tolerance, in both male and female F1 offspring, but these disorders were seen only in female F2 offspring. The study did not examine F3 offspring.

“This suggests that paternal DCHP exposure can lead to sex-specific transgenerational effects on the metabolic health of their progenies,” Zhou said. “At this time, we do not know why the disorders are not seen in male F2 offspring.”

Zhou stressed that the impact of exposure to DCHP on human health is not well understood, even though DCHP is widely used in a variety of plastic products and has been detected in food, water, and indoor particulate matter. DCHP has also been found in human urinary and blood samples. Indeed, the U.S. Environmental Protection Agency recently designated DCHP as one of 20 high-priority substances for risk evaluation.

“It’s best to minimize our use of plastic products,” Zhou said. “This can also help reduce plastic pollution, one of our most pressing environmental issues.”

Zhou, whose earlier mouse study showed exposure to DCHP leads to increased plasma cholesterol levels, was joined in the current study by Jingwei Liu, Junchao Shi, Rebecca Hernandez, Xiuchun Li, Pranav Konchadi, Yuma Miyake, and Qi Chen of UCR; and Tong Zhou of University of Nevada, Reno School of Medicine.

The study was partially supported by grants from the National Institutes of Health and American Heart Association. Hernandez was supported by a National Institutes of Health training grant and an American Heart Association predoctoral fellowship.

The title of the paper is “Paternal phthalate exposure-elicited offspring metabolic disorders are associated with altered sperm small RNAs in mice.”

The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment is more than 26,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual impact of more than $2.7 billion on the U.S. economy. To learn more, visit www.ucr.edu.

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JOURNAL

Environment International

DOI

10.1016/j.envint.2023.107769 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Paternal phthalate exposure-elicited offspring metabolic disorders are associated with altered sperm small RNAs in mice

ARTICLE PUBLICATION DATE

23-Jan-2023