Small-scale foragers left more than footprints on the landscape

Peer-Reviewed Publication

PENN STATE

 

IMAGE: ARCHAEOLOGICAL SITES IN SOUTHWEST MADAGASCAR CONTAIN A VARIETY OF ARTIFACTS, INCLUDING DECORATED CERAMICS AND SHELL TOOLS. view more 

CREDIT: DYLAN DAVIS, PENN STATE

Archaeological sites like the Great Wall of China and the pyramids can be seen with the naked eye from space, but for ancient societies that did not build, their traces on the landscape are more difficult to find. Now Penn State researchers have used satellite data to identify areas in coastal southwest Madagascar where indigenous foragers altered their surroundings.

“One of the things I’m interested in is exploring the different ways that people leave a footprint on the landscape and understanding how long the traces of that footprint last,” said Dylan S. Davis, graduate student in anthropology, Penn State. “For a small-scale society that doesn’t build structures, how do they impact the landscape, and will that impact last thousands of years?”

Using high-resolution PlanetScope satellite imaging and vegetative indices to show how the landscape co-evolved with humans, and then a random forest algorithm and statistics to quantify the amount that humans changed their surroundings, the researchers were able to identify areas of human alteration.  They report their results in Frontiers in Ecology and Evolution.

Archaeologists often looked at agricultural and pastoral societies in the past and catalogued the changes these lifestyles make in the landscape. Permanent or semi-permanent housing, fields and other structures dot the area and, in some places, completely change the natural landscape, but the impact on the landscape of hunter-gatherers is usually confined to temporary living locations and the remains are a few broken pieces of pottery, fire pits or animal bones. The assumption was that these communities did not alter the overall landscape.

In coastal southwestern Madagascar, most archaeological sites for fishing and gathering communities are ephemeral. There are no large buildings, but the record of use for some rock shelters goes back thousands of years. Even though these sites were only occupied part of the year, they were inhabited year after year.

“What we found was that the areas surrounding these sites, that appear to be pristine, are not,” said Davis. “We see a slight shift in the soil’s capacity to absorb water. This is indicated by a shift in spectral reflectiveness seen in the satellite images.”

The study area encompassed 250 to 300 square miles and showed that 17% of that area was changed by humans.

“The landscape changes may be subtle, but they are widespread,” said Davis.

The researchers compared the areas around known archaeological sites to areas without known sites and found a statistical difference between the forests. They found indications that the distribution of plants differed between known sites and uninhabited areas.

“What we don’t know is whether these types of changes in soil chemistry allowed people to occupy the areas in time of drought,” said Kristina Douglass, assistant professor of anthropology and African studies. "Or whether it allowed the ground to retain moisture and grow different plants.”

Douglass notes that animals in this area are drought-adapted so a slight increase in moisture could make a big difference in the animals that occupied the areas around inhabited sites.

According to the researchers, there are long-lasting, landscape-scale effects of settlement, and their work reinforces previous research that found that ancient communities actively modified their ecological surroundings in ways that increased the suitability of previously settled areas.

“We underestimate the impacts that non-agriculture societies have on shaping landscapes. These are subtle, but can be discovered,” said Douglass. “Looking at landscapes across the world, we find that people modified more of the world than we thought before.”

The National Science Foundation, National Geographic Society, Lewis and Clark Fund Grant from the American Philosophical Society, Explorers Club, NASA Space Grant Consortium, Sigma Xi, and Penn State Institute for Computational and Data Sciences supported this work.

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JOURNAL

Frontiers in Ecology and Evolution

DOI

10.3389/fevo.2021.689399 

ARTICLE TITLE

Remote Sensing Reveals Lasting Legacies of Land-Use by Small-Scale Foraging Communities in the Southwestern Indian Ocean

ARTICLE PUBLICATION DATE

3-Sep-2021

How a bacterium may help solve the plastic pollution crisis

Researchers from Nara Institute of Science and Technology find that the bacterium Ideonella sakaiensis can not only degrade petroleum-based plastics but can also sustainably produce biodegradable plastics

Peer-Reviewed Publication

NARA INSTITUTE OF SCIENCE AND TECHNOLOGY

 

IMAGE: I. SAKAIENSIS GROWN ON POLY(ETHYLENE TEREPHTHALATE) (PET) ACCUMULATES POLY(3-HYDROXYBUTYRATE) (PHB). view more 

CREDIT: SHOSUKE YOSHIDA

Ikoma, Japan – Plastic pollution is one of the most pressing environmental issues of our time. The accumulation of petroleum-based plastics is having devastating effects on our environment, wildlife and human health. In a recent study published in Scientific Reports, researchers from Nara Institute of Science and Technology revealed a bacterium that is not only able to degrade difficult-to-recycle petroleum-based plastics but can also sustainably produce more environmentally friendly biodegradable plastics.

Petroleum-based plastics, including poly(ethylene terephthalate) (PET), are extensively used in everyday products, such as single-use plastic bottles, textiles and food wrappers. While such products are disposed of rapidly after use, they persist in the environment for hundreds of years. The plastic pollution resulting from our throw-away culture has now exceeded manageable levels and is overwhelming the planet’s ability to deal with it. The environmental impacts are becoming increasingly obvious, with wildlife and human health increasingly threatened.

Although reducing the manufacture of unnecessary single-use plastics and improving waste management systems will help ease the pollution crisis, our reliance on the convenience of plastic products is unlikely to be abated any time soon. Researchers are therefore looking at alternative approaches to “clean up” the more persistent plastics from our environment and it appears that microbes may offer some promising solutions.

“Certain bacteria harbor the necessary enzymes to degrade PET, the most problematic plastic environmentally,” explains senior author Shosuke Yoshida. “Our research has shown that the bacterium Ideonella sakaiensis converts PET into poly(3-hydroxybutyrate) (PHB), a type of poly(hydroxyalkanoate) (PHA) plastic that is biodegradable,” he continues.

This finding is particularly promising because it addresses two current problems for the sustainability of plastics: degrading the most persistent form of petroleum-based plastic while sustainably producing biodegradable plastics.

“We believe that this discovery could be significant in tackling plastic pollution,” Yoshida states, “as we show that the PET-degradation and PHB-synthesis pathways are functionally linked in I. sakaiensis. This might provide a novel pathway where a single bacterial species breaks down difficult-to-recycle PET plastics and uses the products to make biodegradable PHA plastics.”

Given the overwhelming challenge of dealing with worldwide plastic pollution, this novel bacterial approach may be a significant part of the solution.

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Resource

Title: Direct fermentative conversion of poly(ethylene terephthalate) into poly(hydroxyalkanoate) by Ideonella sakaiensis

Authors: Ryoga Fujiwara, Rikako Sanuki, Hiroharu Ajiro, Toshiaki Fukui & Shosuke Yoshida

Journal: Scientific Reports

Information about Yoshida’s lab can be found at the following website: https://bsw3.naist.jp/eng/courses/courses312.html

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JOURNAL

Scientific Reports

DOI

10.1038/s41598-021-99528-x 

ARTICLE TITLE

Direct fermentative conversion of poly(ethylene terephthalate) into poly(hydroxyalkanoate) by Ideonella sakaiensis

Road impacts on ecosystems in sub-Saharan Africa

Peer-Reviewed Publication

INTERNATIONAL INSTITUTE FOR APPLIED SYSTEMS ANALYSIS

Sub-Saharan Africa is developing rapidly. With growing economies and increased trade, major road infrastructure plans have been developed for the region, which also hosts some of the world’s most unique and diverse ecosystems. New research looked into how roads might impact ecosystems in the region.

Sub-Saharan Africa is one of the most biologically diverse places on the planet. It is home to a variety of iconic flora and fauna such as the African elephant, the baobab tree, and the chimpanzee, and also generates a range of ecosystem goods and services that sustain the livelihoods of many people. Road developments in the region are expected to have large and potentially harmful impacts on natural ecosystems across the region. Many in the conservation community believe that although these roads may benefit growing African communities and economies, they will also promote the overexploitation of African natural resources and further biodiversity loss.

Most of the current literature on the ecological effects of roads tends to focus on single species, and the effects noted are almost always easily identifiable and quantifiable. Roads however, affect entire ecosystems, including plant and animal communities, regional hydrology, geological formations, and even the chemistry of the air above. Previous research efforts have concentrated on the outcome rather than the mechanisms underlying road-species interactions.

Wanting to consider a more multidimensional approach, a new study by researchers from the International Institute of Applied Systems Analysis (IIASA), Austria and the University of Cape Town (UCT), South Africa published in Environmental Research Letters, set out to analyze the impacts past road projects in the region have had on ecosystems inside and outside protected areas across sub-Saharan Africa. The researchers reviewed 137 peer reviewed articles in search of documented reports of the effects of roads and their underlying mechanisms in areas across the region. Reports and evidence were divided into the four main regions of sub-Saharan Africa: Central Africa, East Africa, southern Africa, and West Africa. When analyzing the effects on biodiversity, specific taxonomic groups were also reviewed separately. All effects noted by the researchers contained identified mechanisms such as roads acting as barriers to movement or as a habitat, and by facilitating access, specifically to previously inaccessible land, markets, cities, and economic opportunities.

“Mitigating and managing the effects of future road development in sub-Saharan Africa will require researchers and environmental assessment practitioners to predict where interactions will happen and whether it is likely to affect ecosystem functionality. Thus far, our understanding of how roads can impact natural ecosystems has been dominated by research from North America and Europe. Apart from the difference in biophysical characteristics, the stark differences in socioeconomic, political, and demographic factors in the region leads to unique ways in which roads can interact with ecosystems,” explains IIASA Young Scientists Summer Program (YSSP) alumna Lavinia Perumal, lead author of the study currently associated with UCT.

The results show that roads both inside and outside protected areas, for the most part, had negative impacts on biodiversity. While protected areas were slightly more effective at reducing road-related animal mortality, the data shows that roads inside protected areas still restrict animal movement. Another interesting finding was that these interactions were not the same between regions, leading the authors to conclude that while new road development in and around protected areas across sub-Saharan Africa is problematic, they may pose the greatest risks in Central Africa.

Overall, it was clear that roads play a significant role in altering species distribution and land use patterns throughout the region. The researchers found that road-induced access was one of the main mechanisms by which these impacts developed. Access for illegal hunters and loggers into natural habitats and to markets often influenced species abundance and movement. Accessibility, specifically access to previously inaccessible land, markets, cities, and economic opportunities, was also associated with an increase in built-up area, urbanization, logging, and cropland expansion in the region. Although there were reports of roads having no significant or even a positive impact on species, there was less certainty around the mechanisms causing these effects since many were either speculated or unknown.

The researchers point out that for a developing region like sub-Saharan Africa, this is as much a socioeconomic issue as it is environmental. It is impossible to ignore the role of poverty, gender, governance, or even food insecurity as the reported effects do not always operate in isolation and are often dependent on several biophysical and socioeconomic factors. Poaching, illegal harvests, human-wildlife conflict, and future land use are all things that also need to be taken into account. In fact, land use change is predicted to be one of the largest drivers of biodiversity loss in Africa, which can be worrying for conservationists, as road development is one of the first steps in the facilitation of land use.

“Although it is important to protect ecologically sensitive areas, the complex nature of accessibility in sub-Saharan Africa should not be ignored in future road design and conservation strategies. Achieving a balance of both environmental and development needs is a challenge that the region is going to have to address,” concludes study coauthor and IIASA researcher Matthias Jonas.

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Reference
Perumal, L., New, M.G., Jonas, M., Liu, W. (2021). The impact of roads on sub-Saharan African ecosystems: A systematic review. Environmental Research Letters. DOI: 10.1088/1748-9326/ac2ad9

About IIASA:

The International Institute for Applied Systems Analysis (IIASA) is an international scientific institute that conducts research into the critical issues of global environmental, economic, technological, and social change that we face in the twenty-first century. Our findings provide valuable options to policymakers to shape the future of our changing world. IIASA is independent and funded by prestigious research funding agencies in Africa, the Americas, Asia, and Europe. www.iiasa.ac.at

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JOURNAL

Environmental Research Letters

DOI

10.1088/1748-9326/ac2ad9 

ARTICLE TITLE

The impact of roads on sub-Saharan African ecosystems: A systematic review

ARTICLE PUBLICATION DATE

19-Oct-2021

Disclaimer: AAAS and EurekA

Agricultural runoff contributes to global warming - New study helps us figure out how and what we can do about it

Mechanics of how rivers, bearing increased loads of nitrogen, emit greenhouse gasses revealed by UMass Amherst Researcher

Peer-Reviewed Publication

UNIVERSITY OF MASSACHUSETTS AMHERST

 

IMAGE: MATTHEW WINNICK view more 

CREDIT: UMASS AMHERST

AMHERST, Mass. – Nitrous oxide (N2O) is a potent greenhouse gas, with 300 times the warming ability of carbon dioxide. Due to fertilizer runoff from farm fields, an increasing load of nitrogen is washing into rivers and streams, where nitrogen-breathing microbes break some of the fertilizer down into N2O, which the river releases into the atmosphere as it tumbles toward the ocean. But, until now, scientists haven’t had a clear picture of how the process works, what fraction of the runoff winds up as N2O or what steps might be taken to mitigate N2O emissions.

“Humans are fundamentally altering the nitrogen cycle,” says Matthew Winnick, sole author of the new paper, published recently in AGU Advances, and professor of geosciences at the University of Massachusetts Amherst. “We’ve changed how nitrogen moves through the environment.” Much of this change can be attributed to enormous amounts of nitrogen-rich chemical fertilizers, spread upon agricultural fields, which run off into streams and rivers when it rains, and get converted to nitrate.

Scientists have long known that microbes in the soil and streambed contribute to the “denitrification process,” whereby nitrate is converted to either harmless dinitrogen gas or N2O. But the exact mechanics of the conversion processes have remained a mystery, as evidenced by the wide range of N2O emissions estimates—somewhere between .5% and 10% of global emissions—annually attributable to streams.

Winnick’s innovation was to revisit a large experimental dataset that quantified N2O in 72 streams across the US using a combination of chemical reaction models, which can trace how nitrogen is transformed through a stream system, and stream turbulence models, which capture how the mechanical forces of the river itself deliver nitrate to the stream’s bed, which is where denitrification occurs.

This novel combination, pairing the high resolution of the chemical reaction model with the turbulence model, allowed Winnick to see how nitrate moved from the stream to the streambed and was key to his discovery. 

It turns out that what effectively determines the production of N2O is “denitrification efficiency,” or the fraction of nitrate, delivered to the streambed, that is subjected to the various reactions in the denitrification process. The greater the streambed’s efficiency in converting nitrate, the less N2O is released. But where denitrification efficiency is low, Winnick found comparatively higher levels of N2O emissions.

Furthermore, the bed of the stream to which the nitrate is delivered also plays an important role. Streambeds studded with small anoxic zones, or patches starved of oxygen, also help prevent the release of N2O.

Winnick suggests that this new understanding of nitrogen cycling could help inform efforts at climate-change mitigation. “Increasing the ability of streams to process anthropogenic nitrogen may also reduce proportional N2O emissions,” he writes.

Contacts: Matthew Winnick, mwinnick@umass.edu

                 Daegan Miller, drmiller@umass.edu

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JOURNAL

AGU Advances

DOI

https://doi.org/10.1029/2021AV000517 

ARTICLE TITLE

Stream Transport and Substrate Controls on Nitrous Oxide Yields From Hyporheic Zone Denitrification

ARTICLE PUBLICATION DATE

14-Oct-2021

Climate change affects animal behavior

Peer-Reviewed Publication

UNIVERSITY OF HELSINKI

 

IMAGE: THE RUDDY TURNSTONE (ARENARIA INTERPRES) IS A MARINE WADER BIRD, HERE PICTURED ON A SEASHORE OCCUPIED BY HUMAN SETTLEMENT AT WHITBY, UK. view more 

CREDIT: PETRI NIEMELÄ

Humans are shaping environments at an accelerating rate. Indeed, one of the most important current topics of research is the capacity of animals to adapt to human-induced environmental change and how that change affects the expression of animal traits.

With the help of data collected on a little over one hundred animal species, researchers from the University of Helsinki and Lancaster University studied which behavioural traits are the most sensitive to human-induced environmental change, and to which human-induced changes in the environment animals respond the most sensitively. From the largest to the smallest, the groups of organisms included in the study were fish, birds, crustaceans and mammals. In addition, insects, amphibians and lizards were represented.

All the behavioural traits included in the study – aggression, activity, boldness, sociability and exploration of their environment – changed markedly due to environmental change brought about by humans.

“The biggest change was seen in the animals’ activity in exploring their environment. Animals have a strong response to all forms of environmental change, but climate change engendered the greatest change in animal behaviour,” says Postdoctoral Researcher Petri Niemelä from the Faculty of Biological and Environmental Sciences, University of Helsinki.

In addition to climate change, the other forms of human-induced environmental change included in the modelling were changes in carbon dioxide concentration and nutrient levels, alien species and other biotic changes caused by humans, as well as direct human impact through, for example, urbanisation or other human disturbances.

Changes in activity or other behaviour can often be the initial change in animals instigated by climate change.

“Behavioural change can serve as a buffer with which animals avoid the immediate negative effects of environmental change. For instance, such change can compensate for low reproductive success or increased mortality caused by environmental change. By changing their behaviour, animals can also gain more information on the altered environment.”

The researchers of the University of Helsinki and Lancaster University based the study on a survey of over a thousand scholarly, peer-reviewed, publications, from which the data needed for the analysis were collected on a little over one hundred animal species. The study was published as an open-access publication in the international OIKOS journal series in September 2021.

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JOURNAL

Oikos

DOI

10.1111/oik.08366 

METHOD OF RESEARCH

Meta-analysis

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Understanding behavioural responses to human-induced rapid environmental change: a meta-analysis

ARTICLE PUBLICATION DATE

15-Sep-2021

UVA protection of most sunscreens only a quarter of touted SPF

Peer-Reviewed Publication

ENVIRONMENTAL WORKING GROUP

WASHINGTON – Many sunscreens offer just a quarter of their stated SPF protection against ultraviolet A rays that increase the risk of skin cancer, a new Environmental Working Group study finds.

For the study, EWG scientists tested 51 sunscreens with SPF between 15 and 110.

“Most of the products we tested reduced UV radiation only by half of what would be expected from looking at the SPF on the label,” said David Andrews, Ph.D., a senior scientist at EWG and the lead author of the study unveiled today.

The new research, published in the peer-reviewed journal Photodermatology, Photoimmunology & Photomedicine, used laboratory tests and computer modeling to assess UV ray absorption.

EWG scientists found sunscreens often fell far short of the claims of protection against UVA rays that cause aging, immune harms and greater cancer risks. Most sunscreens also failed to live up to boasts of protection related to UVB rays, which are largely responsible for sunburn.

On average, sunscreens tested in a laboratory but not on people provided a meager 24 percent of UVA protection, compared to the labeled SPF value. That’s much lower than what’s required of sunscreens sold in Europe.

Sunscreen broad spectrum protection often missing

EWG’s research found that most sunscreens provided just 42 to 59 percent of the labeled SPF. Consumers are left without protection against both UVA and UVB.

“Even more concerning is the lack of adequate broad spectrum protection, and that’s a public health problem,” Andrews said. “Broad spectrum products provide protection from UVA rays that are associated with skin cancer, free radical generation and immune harm.

“The sunscreen industry has for too long focused on advertising higher and higher SPF values and UVB rays, not on providing products with stronger UVA protection,” he said.

The findings echo a study released by Food and Drug Administration scientists in 2019 that conceded current sunscreen standards are inadequate. They said switching to sunscreens with higher UVA protection instead of higher SPFs might reduce skin cancer risks.

“Most sunscreen products sold in the U.S. don’t offer adequate protection against both UVA and UVB rays,” said Carla Burns, senior director of cosmetic science at EWG and one of the new study’s coauthors.

“For years, EWG has warned consumers about the safety and efficacy of sunscreens. U.S. store shelves have products that overstate their sun protection claims based on UVB, or sunburn, reduction – without providing similar UVA protection,” Burns said.

“Balanced protection of ultraviolet radiation is important because of the long-term health issues linked to UV exposure – especially harmful UVA rays, which are linked to immunotoxicity and skin cancers,” she added.

Consumers are getting burned by misleading sunscreens

Most evaluations of sunscreen efficacy focus primarily on skin redness, or sunburn, caused by UVB rays. Current U.S. regulations ignore the relationship between the labeled SPF and measured UVA protection.

EWG decided to test 51 sunscreens sold in the U.S. with SPF values from 15 to 110 to assess their broad spectrum protection against both types of UV rays. Scientists used UV-absorption testing and compared those results with computer-modeled protection and the SPF values on product labels.

The findings mean consumers are not only being burned because of misleading sunscreen labels but may also be increasing their risk of skin cancer.

According to the National Cancer Institute, the rate of new melanoma cases among U.S. adults has tripled since the 1970s, from 7.9 per 100,000 people in 1975 to 22.4 per 100,000 in 2018. Although the reasons are unclear, scientists have established that risk factors include family history, indoor tanning, fair skin, freckles, moles, UV radiation and severe sunburns. Growing evidence links UVA exposure to skin cancer.

Skin cancer is one of the most common types of cancer worldwide and the most diagnosed cancer in the U.S. The three most common forms of skin cancer

are basal cell carcinoma, with 4.3 million cases in the U.S. annually; squamous cell carcinoma, with 1.1 million cases annually; and melanoma, with an estimated 106,000 cases annually. But melanoma is the deadliest form of skin cancer, so it warrants particular attention.

“Sunscreen products must be effective, and the ingredients should not cause health harm. Our study shows that sunscreens are not adequately effective, especially at reducing UVA radiation, and the ingredients used in these products have not been fully vetted for safety,” said Andrews.

“An overhaul of sunscreen products and how they are regulated is long overdue. But sunscreens are still important tools in reducing UV exposure – it’s just that some products are better than others,” he added.

FDA renews call for data from sunscreen makers

In September, the FDA released its proposed order detailing lingering concerns about sunscreens. Because of safety uncertainties about the active ingredients in their products, including oxybenzone, the agency also renewed a call for data from manufacturers. Oxybenzone is a potential hormone-disrupting chemical that is readily absorbed by the body  

Sunscreen makers failed to answer the FDA’s 2019 call to conduct studies on the health effects of sunscreens, including the extent chemicals in the products can enter the bloodstream. The FDA says two new studies on the absorption of sunscreen chemicals reinforce the need for the data the agency has sought for more than two years.

“Sunscreen chemicals like oxybenzone pose significant health concerns, but the sunscreen industry continues to bury its head in the sand,” said Scott Faber, EWG’s senior vice president for government affairs. “We’re grateful the FDA continues to demand basic data on the health effects of these chemicals.”

EWG guide identifies sufficiently protective sunscreens

In May 2021, EWG researchers rated the safety and efficacy of more than 1,800 products that advertise sun protection – including recreational sunscreens, daily-use SPF products and lip balms with SPF. They found that only a quarter of the products reviewed offer adequate protection and do not contain worrisome ingredients like oxybenzone.

“The sunscreen market is flooded with products that provide poor UVA protection,” said Faber. “Sunscreen sales have increased dramatically, so sunscreen companies can certainly afford to conduct the studies needed to ensure their customers are safe.”

Current regulations and the U.S. marketplace promote SPF products that reduce sunburn instead of sunscreens that provide better broad spectrum protection. So consumers should make sun safety a daily habit by covering up with clothing, seeking shade, planning around the sun, and using sunscreen when needed.

EWG’s Guide to Sunscreens is one of the only tools available to help consumers find sufficiently protective products made without ingredients that may pose health concerns.

Shoppers can also download EWG’s Healthy Living App to get ratings and safety information on sunscreens and other personal care products right at their fingertips. EWG’s sunscreen label decoder can also help consumers looking for safer sunscreens.

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The Environmental Working Group is a nonprofit, non-partisan organization that empowers people to live healthier lives in a healthier environment. Through research, advocacy and unique education tools, EWG drives consumer choice and civic action. Visit www.ewg.org for more information.

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DOI

10.1111/phpp.12738 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Laboratory testing of sunscreens on the U.S. market finds lower in vitro SPF values than on labels and even less UVA protection

New study calls for mitigation, monitoring of common grease-proofing food packaging chemicals

Peer-Reviewed Publication

IOWA STATE UNIVERSITY

 

IMAGE: KEITH VORST WITH BITS OF RECYCLED BOTTLES INSIDE ONE OF HIS LABORATORIES IN THE FOOD SCIENCES BUILDING. VORST IS STUDYING POTENTIAL MITIGATION STRATEGIES SUCH AS HIGH VOLTAGE ATMOSPHERIC COLD PLASMA TO CHANGE THE CHEMISTRY OF PFAS. view more 

CREDIT: CHRISTOPHER GANNON/IOWA STATE UNIVERSITY NEWS SERVICE

AMES, Iowa – Chemicals used to “grease proof” everything from food packaging to carpets have built up in the environment for decades and contaminate ecosystems across the globe, and a new study is calling for a better understanding of the risks posed by these chemicals

The study, published in the academic journal Trends in Food Science & Technology, collects the proceedings of a symposium chaired by an Iowa State University scientist and issued a call to action on the need for new and better ways to detect and mitigate this class of chemical compounds, collectively known as per- and polyfluoroalkyl substances (PFAS). Evidence indicates exposure to high levels can lead to adverse health effects for humans and other species, and the study stresses the need for new ways to measure and study exposures to these synthetic chemicals from various sources including food.

PFAS accumulate in the environment and do not break down on their own. For instance, the compounds can contaminate waterways after leaching from products discarded in landfills, said Keith Vorst, director of the Polymer and Food Protection Consortium and an associate professor of food science and human nutrition at Iowa State. These entirely manmade chemicals have been used in a wide range of products since the 1940s, and some states have enacted legislation to restrict their use. But their ability to persist in the environment means the compounds that already exist can continue to contaminate the environment.

“They’re out there, we need to be aware of them, and it’s really hard to eliminate them,” Vorst said. “We need to work on mitigation strategies, and we need to be monitoring them and better understand the risks they pose.”

What are PFAS?
PFAS often have been used to coat food packaging as a barrier to keep grease from escaping. Vorst said paper wrappers on hamburgers are often coated in these compounds to prevent grease from leaking onto consumers’ hands. The compounds have also been used widely to coat carpets, in car interiors and in fire-fighting foams.

Some PFAS are no longer produced in the United States, but Vorst said more than 5,000 separate compounds qualify under this category, making it difficult for regulations to keep up with newly developed chemicals.

Studies have indicated that exposure to high levels of some of these chemicals can cause reproductive and developmental, liver and kidney, and immunological effects in laboratory animals, according to the Environmental Protection Agency. The EPA reports the most consistent findings are increased cholesterol levels among exposed populations, and studies have found limited evidence for links between high levels of certain PFAS and low infant birth weights, effects on the immune system, cancer and thyroid hormone disruption. (https://www.epa.gov/pfas/basic-information-pfas)

Monitoring and mitigation
The new paper emerged out of a virtual symposium held in June of 2020 organized by the Institute for the Advancement of Food and Nutrition Sciences. The symposium featured scientists, engineers and regulatory professionals from public, private and academic institutions. The symposium addressed science gaps for exposure routes, detection and quantification of PFAS in food. Speakers also noted that, based on limited data to date, there is little PFAS detected in food.

Polymer and Food Protection Consortium researchers Greg Curtzwiler, an assistant professor of food science and human nutrition, and Paulo Silva, adjunct assistant professor of food science and human nutrition, are working with Vorst in the laboratory to study potential mitigation strategies such as high voltage atmospheric cold plasma to change the chemistry of PFAS. This process could work by passing materials that contains PFAS, such as product packaging or even drinking water, through an engineered atmosphere to mitigate the compounds. The research team has tested the method and is working with Iowa State to patent the technology. Vorst’s PFPC lab has been testing new methodologies to detect and monitor PFAS levels in various environments as well. Much of this research was funded by the ISU Polymer and Food Protection Consortium.

“We’re looking at continuous monitoring of exposure limits,” Vorst said. “We’re trying to develop threshold limits for packaging and products. We’re also looking at how we can change these chemistries to get them out of the environment, make them less persistent or sequester them.”

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DOI

10.1016/j.tifs.2021.05.038 

METHOD OF RESEARCH

Meta-analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Risk assessment of per- and polyfluoroalkyl substances (PFAS) in food: Symposium proceedings

ARTICLE PUBLICATION DATE

19-Oct-2021

Cat bacteria treats mouse skin infection, may help you and your pets as well

Researchers identify a bacteria on healthy cats that produces antibiotics against severe skin infections; the findings may lead to new bacteriotherapies for humans and their pets

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - SAN DIEGO

 

IMAGE: TO IDENTIFY CANDIDATES FOR A NEW BACTERIOTHERAPY AGAINST SKIN INFECTION, RESEARCHERS FIRST SCREENED VARIOUS BACTERIA FROM DOGS AND CATS AND CO-CULTURED THEM WITH <EM>S. PSEUDINTERMEDIUS</EM> IN LIQUID AND AGAR ANTIMICROBIAL ASSAYS. view more 

CREDIT: UC SAN DIEGO HEALTH SCIENCES

Researchers at University of California San Diego School of Medicine used bacteria found on healthy cats to successfully treat a skin infection on mice. These bacteria may serve as the basis for new therapeutics against severe skin infections in humans, dogs and cats. 

The study, published in eLife on October 19, 2021, was led by Richard L. Gallo, MD, PhD, Distinguished Professor and chair of the Department of Dermatology at UC San Diego School of Medicine, whose team specializes in using bacteria and their products to treat illnesses — an approach known as “bacteriotherapy.” 

Skin is colonized by hundreds of bacterial species that play important roles in skin health, immunity and fighting infection. All species need to maintain a diverse balance of healthy skin bacteria to fight potential pathogens.

“Our health absolutely depends on these ‘good’ bacteria,” said Gallo. “They rely on our healthy skin to live, and in return some of them protect us from ‘bad’ bacteria. But if we get sick, ‘bad’ bacteria can take advantage of our weakened defenses and cause infection.” 

This is the case with methicillin-resistant Staphylococcus pseudintermedius (MRSP), a bacterium commonly found on domesticated animals that becomes infectious when the animals are sick or injured. MRSP is an emerging pathogen that can jump between species and cause severe atopic dermatitis, or eczema. These infections are common in dogs and cats, and can also occur in humans, though rates of human infection vary around the world. As its name suggests, MRSP is resistant to common antibiotics and has been difficult to treat in clinical and veterinary settings. 

To address this, researchers first screened a library of bacteria that normally live on dogs and cats and grew them in the presence of MRSP. From this, they identified a strain of cat bacteria called Staphylococcus felis (S. felis) that was especially good at inhibiting MRSP growth. They found that this special strain of S. felis naturally produces multiple antibiotics that kill MRSP by disrupting its cell wall and increasing the production of toxic free radicals.

“The potency of this species is extreme,” said Gallo. “It is strongly capable of killing pathogens, in part because it attacks them from many sides — a strategy known as ‘polypharmacy.’ This makes it particularly attractive as a therapeutic.” 

Bacteria can easily develop resistance to a single antibiotic. To get around this, S. felis has four genes that code for four distinct antimicrobial peptides. Each of these antibiotics is capable of killing MRSP on their own, but by working together, they make it more difficult for the bacteria to fight back.

Having established how S. felis kills the MRSP, the next step was to see whether it could work as a therapy on a live animal. The team exposed mice to the most common form of the pathogen and then added either S. felis bacteria or bacterial extract to the same site. The skin showed a reduction in scaling and redness after either treatment, compared with animals that had no treatment. There were also fewer viable MRSP bacteria left on the skin after treatment with S. felis.

Next steps include plans for a clinical trial to confirm whether S. felis can be used to treat MRSP infections in dogs. Bacteriotherapies like this one can be delivered via topical sprays, creams or gels that contain either live bacteria or purified extract of the antimicrobial peptides. 

While these products are in development, what should pet owners do in the meantime?

“Don’t stop washing your pets to keep these ‘good’ bacteria on them,” said Gallo. “Skin has evolved to protect the ‘good’ bacteria, so soap and detergents don’t usually wash the good guys off.”

“It may even be possible that living with a healthy cat provides humans with some protection against MRSP,” Gallo said, “so this may be an argument in support of pet ownership.”

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This study is part of a growing line of work by Gallo’s group to develop bacteriotherapies for inflammatory skin diseases and skin cancers.

Co-authors include: Alan M. O'Neill, Kate A. Worthing, Nikhil Kulkarni, Fengwu Li, Teruaki Nakatsuji, Dominic McGrosso, Robert H. Mills, Gayathri Kalla, Joyce Y. Cheng, Kit Pogliano, Joe Pogliano and David J. Gonzalez, all at UC San Diego, and Jacqueline M. Norris at the University of Sydney. 

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JOURNAL

eLife

DOI

10.7554/eLife.66793 

ARTICLE PUBLICATION DATE

19-Oct-2021

COI STATEMENT

Richard L. Gallo is a co-founder, scientific advisor, inventor, consultant and has equity in MatriSys Biosciences and is a consultant, receives income and has equity in Sente. Kate A. Worthing is a co-inventor of technology described in this study that has been disclosed to the University of California San Diego.