Cities are making mammals bigger

Peer-Reviewed Publication

FLORIDA MUSEUM OF NATURAL HISTORY

 

IMAGE: AN ANALYSIS OF NEARLY 140,500 MEASUREMENTS OF BODY LENGTH AND MASS FROM MORE THAN 100 NORTH AMERICAN MAMMAL SPECIES COLLECTED OVER 80 YEARS SHOWS CITY-DWELLING MAMMALS ARE LONGER AND HEAVIER THAN THE SAME SPECIES IN RURAL AREAS. view more 

CREDIT: KRISTEN GRACE/FLORIDA MUSEUM OF NATURAL HISTORY

GAINESVILLE, Fla. --- A new study shows urbanization is causing many mammal species to grow bigger, possibly because of readily available food in places packed with people.

The finding runs counter to many scientists' hypothesis that cities would trigger mammals to get smaller over time. Buildings and roads trap and re-emit a greater degree of heat than green landscapes, causing cities to have higher temperatures than their surroundings, a phenomenon known as the urban heat island effect. Animals in warmer climates tend to be smaller than the same species in colder environments, a classic biological principle called Bergmann’s Rule.

But Florida Museum of Natural History researchers discovered an unexpected pattern when they analyzed nearly 140,500 measurements of body length and mass from more than 100 North American mammal species collected over 80 years: City-dwelling mammals are both longer and heftier than their rural counterparts.

“In theory, animals in cities should be getting smaller because of these heat island effects, but we didn’t find evidence for this happening in mammals,” said study lead author Maggie Hantak, a Florida Museum postdoctoral researcher. “This paper is a good argument for why we can’t assume Bergmann’s Rule or climate alone is important in determining the size of animals.”

Hantak and her collaborators created a model that examined how climate and the density of people living in a given area – a proxy for urbanization – influence the size of mammals. As temperatures dropped, both body length and mass increased in most mammal species studied, evidence of Bergmann’s Rule at work, but the trend was stronger in areas with more people.

Surprisingly, mammals in cities generally grew larger regardless of temperature, suggesting urbanization rivals or exceeds climate in driving mammal body size, said Robert Guralnick, Florida Museum curator of biodiversity informatics.

“That wasn’t what we expected to find at all,” he said. “But urbanization represents this new disturbance of the natural landscape that didn’t exist thousands of years ago. It’s important to recognize that it’s having a huge impact.”

About a decade ago, scientists began to raise the alarm that warmer temperatures brought by climate change are causing many animal species to grow smaller over time. While many of the consequences of shifting body size are unknown, researchers cautioned that smaller animals may have smaller or fewer offspring, creating a feedback loop, and shrinking prey could also put pressure on meat-eaters to find more resources.

Guralnick and Hantak said they hope their findings will lead more researchers to add urbanization to their analyses of changing body size.

“When we think about what’s going to happen to mammalian body size over the next 100 years, a lot of people frame that as global warming causing animals to get smaller,” Guralnick said. “What if that isn’t the biggest effect? What if it’s that urbanization is going to lead to fatter mammals?”

Not all animals respond to human-induced environmental changes in the same way, Hantak added. The researchers also investigated how the effects of climate and urbanization may be tempered or amplified by the behavior and habits of certain species.

They found animals that use hibernation or torpor, a temporary way of slowing metabolic rate and dropping body temperature, shrank more dramatically in response to increases in temperature than animals without these traits. The finding could have important implications for conservation efforts, Hantak said.

CAPTION

The study showed that species that use torpor, a temporary way of slowing metabolism and lowering body temperature, were more sensitive to warming temperatures, the opposite of what scientists expected. One such species is the pallid bat, Antrozous pallidus.

CREDIT

Natalie van Hoose/Florida Museum of Natural History

CAPTION

The researchers relied on thousands of measurements taken by natural history scientists in the field and museums to capture a broad picture of how mammal body size has changed over time in human-modified environments.

CREDIT

Natalie van Hoose/Florida Museum of Natural History

“We thought species that use torpor or hibernation would be able to hide from the effects of unfavorable temperatures, but it seems they’re actually more sensitive,” she said.

While cities radically transform the landscape, they provide animals with new opportunities as well as threats, Guralnick said. The abundance of food, water and shelter and relative lack of predators in cities may help certain species succeed in comparison with their neighbors in rural areas. The results of the 2020 U.S. Census show that almost all human population growth over the past decade has occurred in the nation’s metro areas. As urbanization ramps up, animals could be divided into “winners and losers,” and mammal distributions may shift, he said.

“Animals that like living in urban environments could have a selective advantage while other species may lose out because of the continued fragmentation of landscapes,” Guralnick said. “This is relevant to how we think about managing suburban and urban areas and our wildlands in 100 years.”

While bigger is often better biologically, the long-term consequences to urban mammals of eating a diet of human food waste have yet to be determined, Hantak said.

“When you change size, it could change your whole lifestyle,” she said.

Hantak and her collaborators were able to conduct the study thanks to thousands of measurements collected by natural historians in the field and museums. The research team used information from three databases: VertNet, the National Science Foundation's National Ecological Observatory Network (NEON) and the North American Census of Small Mammals (NASCM). Cumulatively, this data offers a broadscale view of how increasing urbanization is impacting mammals with very different life histories, from wolves, bobcats and deer to bats, shrews and rodents, Guralnick said.

“Museum collections have the power to tell us stories about the natural world,” he said. “Because we have these collections, we can ask questions about what mammals looked like before humans dominated the landscape. Digitizing specimen data unlocks these resources so that everyone can make discoveries about our planet.”

The researchers published their findings in Communications Biology.

Bryan McLean of the University of North Carolina Greensboro and Daijiang Li of Louisiana State University also co-authored the study. McLean and Li are former Florida Museum postdoctoral researchers.

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JOURNAL

Communications Biology

DOI

10.1038/s42003-021-02505-3

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Mammalian body size is determined by interactions between climate, urbanization, and ecological traits.

ARTICLE PUBLICATION DATE

16-Aug-2021

COI STATEMENT

n/a

KAPITALISMUS KILLS

Night shift work is linked to increased risk of heart problems

Peer-Reviewed Publication

EUROPEAN SOCIETY OF CARDIOLOGY

 

IMAGE: THIS STUDY DEMONSTRATES THAT BOTH CURRENT AND LIFETIME NIGHT SHIFT EXPOSURES WERE ASSOCIATED WITH INCREASED RISK OF ATRIAL FIBRILLATION AND CORONARY HEART DISEASE. view more 

CREDIT: EUROPEAN HEART JOURNAL

People who work night shifts are at increased risk of developing an irregular and often abnormally fast heart rhythm called atrial fibrillation (AF), according to research published in the European Heart Journal [1].

The study is the first to investigate the links between night shift work and AF. Using information from 283,657 people in the UK Biobank database, researchers found that the longer and more frequently that people worked night shifts over their lifetimes, the greater their risk of AF. Night shift work was also linked to an increased risk of heart disease, but not to stroke or heart failure.

In addition, the researchers, led by Professor Yingli Lu, of Shanghai Ninth People’s Hospital and Shanghai JiaoTong University School of Medicine, Shanghai, China, and Professor Lu Qi, of Tulane University School of Public Health and Tropical Medicine, New Orleans, USA, investigated whether genetic predisposition to AF could play a role in the increased risk. They evaluated the overall genetic risk on the basis of 166 genetic variations known to be associated with the condition but found that the genetic risk levels did not affect the link between working night shifts and AF risk, regardless of whether participants had a low, medium or high genetic risk.

Prof. Lu said: “Although a study like this cannot show a causal link between night shifts and atrial fibrillation and heart disease, our results suggest that current and lifetime night shift work may increase the risk of these conditions.

“Our findings have public health implications for preventing atrial fibrillation. They suggest that reducing both the frequency and the duration of night shift work may be beneficial for the health of the heart and blood vessels.”

The study included 286,353 people who were in paid employment or self-employed. A total of 283,657 of these participants did not have AF when they enrolled in UK Biobank, and 276,009 did not have heart failure or stroke. Information on genetic variants was available for 193,819 participants without AF, and 75,391 of them answered in-depth questions about their lifetime employment in a questionnaire sent out in 2015. Among the participants free of heart disease and stroke when they joined the study, 73,986 provided information on their employment history. During an average follow-up time of over ten years, there were 5,777 AF cases.

The researchers adjusted their analyses for factors that could affect the results, such as age, sex, ethnicity, education, socioeconomic status, smoking, physical exercise, diet, body mass index, blood pressure, sleep duration and chronotype (whether someone was a ‘morning’ or an ‘evening’ person).

They found that people who currently worked night shifts on a usual or permanent basis had a 12% increased risk of AF compared to people who only worked during the day. The risk increased to 18% after ten or more years for those who had a lifetime duration of night shifts. Among people who worked an average of three to eight night shifts a month for ten years or more, the risk of AF increased to 22% compared to daytime workers.

Among participants currently working night shifts, or working night shifts for ten or more years, or working a lifetime of three to eight night shifts a month, the risk of coronary heart disease increased by 22%, 37% and 35% respectively compared to daytime workers.

Prof. Qi said: “There were two more interesting findings. We found that women were more susceptible to atrial fibrillation than men when working night shifts for more than ten years. Their risk increased significantly by 64% compared to day workers. People reporting an ideal amount of physical activity of 150 minutes a week or more of moderate intensity, 75 minutes a week or more of vigorous intensity, or an equivalent combination, had a lower risk of atrial fibrillation than those with non-ideal physical activity when exposed to a lifetime of night shift work. Thus, women and less physically active people may benefit particularly from a reduction in night shift work.”

A strength of the study is its size, with detailed information on over 283,000 people. In addition, it is the first study to link these data with genetic information in a population that also has detailed histories available on current shift work and lifetime employment.

Limitations of the study include the fact that it cannot show shift work causes heart problems, only that it is associated with them; some cases of atrial fibrillation may have been missed; lifetime employment was assessed only when people joined UK Biobank, was self-reported and, therefore, may have changed or be prone to some errors; there may be unknown factors that might affect the results; and the people in UK Biobank were mainly white British and so it may not be possible to generalise the findings to other ethnic groups.

Prof. Lu said: “We plan to analyse the association between night shift work and atrial fibrillation in different groups of people. This may strengthen the reliability of these results and serve as a warning to groups working in certain types of occupations to get their hearts checked early if they feel any pain or discomfort in their chests.”

(ends)

[1] “Long-term night shift work is associated with the risk of atrial fibrillation and coronary heart disease”, by Ningjian Wang et al. European Heart Journal. doi:10.1093/eurheartj/ehab505

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JOURNAL

European Heart Journal

DOI

10.1093/eurheartj/ehab505

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Long-term night shift work is associated with the risk of atrial fibrillation and coronary heart disease

ARTICLE PUBLICATION DATE

9-Aug-2021

COI STATEMENT

None declared

 

First genetic sequencing of Brazilian pit viper is completed

In an article published in PNAS, researchers affiliated with Butantan Institute describe the genome of Bothrops jararaca and suggest the origin of genes responsible for toxins in its venom.

Peer-Reviewed Publication

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO

 

IMAGE: RESEARCHERS DESCRIBE THE GENOME OF BOTHROPS JARARACA AND SUGGEST THE ORIGIN OF GENES RESPONSIBLE FOR TOXINS IN ITS VENOM view more 

CREDIT: RAFAEL MARQUES PORTO/INSTITUTO BUTANTAN

A group led by researchers at Butantan Institute and funded by São Paulo Research Foundation - FAPESP has completed the first sequencing of a Brazilian snake’s genome. The study is reported in an article published in the journal PNAS. It suggests that the nine genes that encode toxins produced by the jararaca pit viper Bothrops jararaca probably originated in genes that had different functions in the ancestral species.

“In sequencing the snake’s genome, we identified markers that enabled us to compare toxin genes with genes in the same position in the genomes of other animals, such as snakes without venom, lizards and amphibians. We found nine of the 12 toxin genes in the jararaca to be highly similar to those occupying the same position in the DNA of these other species. We concluded that most of the toxin genes probably arose from elements that already existed in the same part of the genome of the ancestor common to all these animals,” said Inácio Junqueira de Azevedo, a researcher at Butantan Institute and last author of the article.

Azevedo is a principal investigator at the Center for Research on Toxins, Immune Response and Cell Signaling (CeTICS), one of the Research, Innovation and Dissemination Centers (RIDCs) funded by FAPESP.

“These genes had physiological functions in the common ancestor of all these species. At some point they probably began playing a role similar to toxin genes or were selected for this route and lost their original functions. Our study located elements that will help scientists understand the evolution of toxins and the mechanisms that led to the recruitment of certain genes to perform this new function in the production of venom,” said Diego Dantas Almeida, first author of the article. The study was conducted during his PhD research, which was supported by FAPESP.

The sequencing also showed that two genes that encode important toxins probably originated in duplication. In any organism, a gene normally evolves more freely and ends up performing different functions when a copy performs its original functions.

In the jararaca, the copies must have come under selective pressure to produce two families of toxins that account for most of the venom’s action: snake venom metalloproteinases (SVMPs) and phospholipases A2 (PLA2). Most of the genes that encode toxins in this snake were already thought to have originated in this manner. It was impossible to determine the origin of only one of the 12 gene families that encode its toxins.

“We were able to show that non-toxic ‘ancestral’ genes exist in these two families. They’re still present in the DNA, right alongside the toxin genes. The ancestral genes have completely disappeared from the other families. They’ve probably been transformed into toxin genes,” said Vincent Louis Viala, a co-author of the article and former recipient of a postdoctoral fellowship from FAPESP.

Research effort

The Butantan Institute group began sequencing this snake’s genome in 2013. B. jararaca is responsible for a large proportion of snake-bite accidents in Brazil and is one of the most studied snakes for this reason. The sequencing produced the fundamental information on the origins of its venom they had lacked hitherto.

In addition to enhancing knowledge of the genes in an organism, sequencing its genome assembles them in the right order. This is one of the most complex parts of the task because sequencing generates a vast amount of data, which has to be processed using computational tools.

Only in recent years, after combining several methods, did the group succeed in assembling the genome satisfactorily, with the collaboration of researchers at Ohio State University in the United States. The complete genome sequence is available online to anyone who wishes to study it.

The project produced answers to several other key questions. In 2009, an analysis by Japanese researchers of certain toxin genes from Protobothrops flavoviridis, which belongs to the same family as the jararaca (Viperidae), suggested the gene that encodes the toxin VEGF-F, also present in the Brazilian snake, probably resulted from duplication of the gene VEGF-A. The Brazilian group have now shown that it is more likely to have originated in a different gene family known in the scientific literature as “PGF-like”.

The group also assembled more evidence that bradykinin-potentiating peptides (BPP), which are the basis for the anti-hypertensive drug captopril, probably originated in the gene CNP, which encodes C-type natriuretic peptides present in other vertebrates, including humans.

“The study illustrates the need to identify the context in which genes are inserted in order to understand their origin and evolution correctly,” Azevedo said.

The researchers are now working on more refined versions of the jararaca’s genome and those of other venomous snake families, hoping to find novel toxins and link them to proteins of relevance in the physiology of other organisms.
The study was also funded via a Thematic Project conducted under the aegis of the FAPESP Research Program on Biodiversity Characterization, Conservation, Restoration and Sustainable Use (BIOTA-FAPESP) and a Regular Research Grant awarded to Azevedo.

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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 http://www.fapesp.br/en and visit FAPESP news agency at http://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

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2015159118

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Tracking the recruitment and evolution of snake toxins using the evolutionary context provided by the Bothrops jararaca genome

ARTICLE PUBLICATION DATE

18-May-2021

Insects’ sense of smell gives insight into better repellent design and drug screening

Peer-Reviewed Publication

SKOLKOVO INSTITUTE OF SCIENCE AND TECHNOLOGY (SKOLTECH)

Skoltech researchers and their colleagues have studied a core element of the insect olfactory system to see how this knowledge might help in both fighting insects and using them to our advantage. The paper was published in the journal Molecular Biology Reports.

Olfaction, or the ability to detect odorous chemical substances, is one of the universal senses shared by all sorts of living organisms. How important it is for an organism’s survival varies across species, and generally the more important it is, the more intricate structures evolve to provide information about smells and odors. In insects, olfaction guides a lot of sexual and social behavior, so their chemosensing arsenal is quite diverse, with hundreds of genes encoding olfactory receptors tuned to specific compounds, or ligands.

“On the one hand, our interaction with the insect world is of great economic importance. Insects can be both our enemies (agricultural pests, vectors of dangerous infections) and friends (pollinators, producers of food substances). And the sense of smell is an important determinant of their behavior. On the other hand, the enormous diversity of insect chemoreceptors can find applications in the development of new scientific approaches, for example, in drug screening. The paradox here is that we still do not have a general picture of the olfaction mechanisms in insects,” Skoltech Professor Konstantin Lukyanov said.

Lukyanov and Skoltech PhD student Elena Sokolinskaya were part of the team that studied the functioning of Orco, a co-receptor that is fundamental to olfaction in insects, in a HEK293 cell line. Since Orco is a highly conserved constant subunit of any receptor of the OR family, meaning it’s very stable and ubiquitous, it is the most versatile target for studying insect olfactory regulation.

“We found that the functional “tuning” of the chemoreceptor, for example, its sensitivity and responsiveness, and maybe even the signal transduction mechanism, depends on the identity of its ligand-binding subunit dramatically. This means that the OR family of receptors is very diverse in its molecular functioning mechanisms,” Lukyanov said.

According to the authors, these findings can be relevant in repellent design and drug screening, although Lukyanov notes that research efforts should be targeted to specific receptors of specific insect species as “it is hardly possible to be guided by the observations and conclusions made only on the Drosophila model.”

“At the moment, we can also say that insect chemoreceptors are potentially applicable in ‘mammalian’ chemogenetics; we are currently testing a wider palette of receptors in the primary cultures of electroexcitable cells,” Lukyanov concluded.

Other organizations involved in this research include the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry and the Institute of Higher Nervous Activity and Neurophysiology.

*****

Skoltech is a private international university located in Russia. Established in 2011 in collaboration with the Massachusetts Institute of Technology (MIT), Skoltech is cultivating a new generation of leaders in the fields of science, technology and business, is conducting research in breakthrough fields, and is promoting technological innovation with the goal of solving critical problems that face Russia and the world. Skoltech is focusing on six priority areas: data science and artificial intelligence, life sciences, advanced materials and modern design methods, energy efficiency, photonics and quantum technologies, and advanced research.  Web: https://www.skoltech.ru/.

 

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JOURNAL

Molecular Biology Reports

DOI

10.1007/s11033-021-06480-0

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Impacts of OrX and cAMP-insensitive Orco to the insect olfactory heteromer activity

ARTICLE PUBLICATION DATE

10-Jun-2021

Changes in Canada’s cannabis retail market 2 years after legalization

Cannabis shops still concentrating in low-income neighborhoods

Peer-Reviewed Publication

THE OTTAWA HOSPITAL

 

IMAGE: DR. DANIEL MYRAN, A POSTDOCTORAL FELLOW AT THE OTTAWA HOSPITAL AND THE UNIVERSITY OF OTTAWA DEPARTMENT OF FAMILY MEDICINE. view more 

CREDIT: THE UNIVERSITY OF OTTAWA

A recent study by public health researchers published in Drug and Alcohol Review documents the rapid expansion of the cannabis retail market in Canada in the two years following legalization.

The researchers found that the legal cannabis market increased from 158 stores (0.5 stores per 100,000 individuals) one month after legalization to 1,183 stores (3.7 stores per 100,000 individuals) two years after legalization – a 648% increase.

Similar to the team’s previous study 6 months after legalization, they found there were twice as many cannabis stores concentrated in low-income neighbourhoods compared to high-income neighbourhoods.

There was also enormous variation in market maturity between provinces and territories. For example, Alberta and the Yukon had 24 times more cannabis stores per capita than Quebec two years after legalization.

Jurisdictions with private retail models (where cannabis stores are privately owned and operated) had more stores and saw a 913% increase in store growth over time, compared to public models (where stores are owned and operated by the government) which saw a 75% increase in store growth.

The researchers suggest the variations between jurisdictions may impact their ability to meet the public health goals of cannabis legalization – reducing harmful youth use and eliminating the illicit market.

In addition, the team notes that Canada’s legal market remained immature in many regions two years after legalization. This market immaturity cautions against studies assessing the impact of legalization on cannabis use and related- health outcomes using data only for the first two years.

“A lot of studies to date have looked at cannabis use in the year following legalization, not seen very dramatic changes, and concluded that legalization really doesn’t have much of an impact on cannabis use and related health outcomes,” said Dr. Daniel Myran, a postdoctoral fellow at The Ottawa Hospital and the University of Ottawa Department of Family Medicine.  “What our data suggests is that we should not really have expected major changes right after legalization because of market immaturity. I anticipate that its only now that the market is taking off that we will see the potential impacts of legalization on cannabis use and related health outcomes.”

###

This study comes in advance of the three-year review of the Cannabis Act by Canadian lawmakers, which will start in October 2021.

About The Ottawa Hospital 
The Ottawa Hospital is one of Canada’s top learning and research hospitals, where excellent care is inspired by research and driven by compassion. As the third-largest employer in Ottawa, our support staff, researchers, nurses, physicians, and volunteers never stop seeking solutions to the most complex health-care challenges. Our multi-campus hospital, affiliated with the University of Ottawa, attracts some of the most influential scientific minds from around the world. Backed by generous support from the community, we are committed to providing the world-class, compassionate care we would want for our loved ones. www.ohri.ca

About the University of Ottawa
The University of Ottawa is home to over 50,000 students, faculty and staff, who live, work and study in both French and English. Our campus is a crossroads of cultures and ideas, where bold minds come together to inspire game-changing ideas. We are one of Canada’s top 10 research universities—our professors and researchers explore new approaches to today’s challenges. One of a handful of Canadian universities ranked among the top 200 in the world, we attract exceptional thinkers and welcome diverse perspectives from across the globe. www.uottawa.ca

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JOURNAL

Drug and Alcohol Review

DOI

10.1111/dar.13351

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

How has access to legal cannabis changed over time? An analysis of the cannabis retail market in Canada 2 years following the legalisation of recreational cannabis

ARTICLE PUBLICATION DATE

12-Jul-2021

 

Metal pollution: If it’s in the air – and our iPhones - it’ll end up in our bones

Lead found in 12,000 Year old skeletons reflects increasing rates of lead production, toxic exposure and a harbinger of things to come, Hebrew University study finds

Peer-Reviewed Publication

THE HEBREW UNIVERSITY OF JERUSALEM

In our increasingly industrialized world, what we produce “out there” has a direct impact on what happens in here, inside our bodies.  A new study by Hebrew University of Jerusalem (HU) reveals the link between rates of metal production and toxic lead exposure in humans.  The research team closely examined human remains from a burial ground in central Italy that was in consecutive use for 12,000 years. 

They found that as worldwide lead production began and increased, so, too, did the rates of lead absorption found in people who lived during those time periods—even those not remotely involved in lead production—simply by breathing the air around them.  This observation of the toxic effects of metal pollution has wide-reaching implications for public health given the forecasted increase in production of lead and other metals to keep up with manufacturing demands for electronic devices, batteries, solar panels and wind turbines, among others.

Professor Yigal Erel at Hebrew University of Jerusalem (HU)’s Institute of Earth Sciences led the study, along with HU colleagues Prof. Liran Carmel, Adi Ticher and Ofir Tirosh, as well as, University of Vienna’s Ron Pinhasi and Sapienza University of Rome’s Alfredo Coppa. Their findings were published today in Environmental Science and Technology. 

We often think of lead in terms of paint and pipes.  However, lead production has its own rich history, beginning several millennia ago.  A big boost in lead production began 2,500 with coin production, an uptick that reached its peak during the Roman Period before declining during the Middle Ages.  Beginning 1,000 years ago, lead production was on the rise again, prompted by silver mining in Germany, then in the New World, and finally to meet the demands of the Industrial Revolution.

While increases in lead production rates are noted in our environmental archives, such as glaciers and sediments from lakes, lead concentrations in human bones and teeth seldom told the outside story of worldwide lead production rates, until now. As part of their research, the scientists analyzed bone fragments from 130 people who lived in Rome, from as early as 12,000 years ago—well before the advent of metal production—until the 17th century.  [LC1] By analyzing the elemental composition found in their bones, the researchers were able to compute the level of lead pollution over time, and showed that it closely mimicked the rate of worldwide lead production.

“This documentation of lead pollution throughout human history indicates that, remarkably, much of the estimated dynamics in lead production is replicated in human exposure. Thus, lead pollution in humans has closely followed their rates of lead production,” explained Erel. “Simply put: the more lead we produce, the more people are likely to be absorbing it into their bodies.  This has a highly toxic effect,” Erel shared.

Aside from the history lesson in lead production rates, exposure from our earlier times is a harbinger for the health effects of lead production for our ever-industrializing world today and in the future.  Studies have shown that toxic lead exposure in people, especially in children, takes place through diet, air-pollution and urban soil resuspension.  Alongside these concerns, we’re seeing an ever-mounting demand for metals in the manufacturing of electronic devices. “The close relationship between lead production rates and lead concentrations in humans in the past, suggests that without proper regulation we will continue to experience the damaging health impacts of toxic metals contamination,” Erel warned.

While those most directly affected by these dangers are people with the highest exposure to lead, namely miners and employees in recycling facilities, lead can be found throughout our daily lives in the form of batteries and the new generation of solar panels that deteriorate over time and release their toxicity into the air we breathe and the soil from which we grow our crops.  “Any expanded use of metals should go hand in hand with industrial hygiene, ideally safe metal recycling and increased environmental and toxicological consideration in the selection of metals for industrial use,” Erel concluded.

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DOI

10.1021/acs.est.1c00614

METHOD OF RESEARCH

News article

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Lead in archaeological human bones reflecting historical changes in lead production.

ARTICLE PUBLICATION DATE

15-Aug-2021

 

From coral reef to goat ranch: Uncovering the botanical history of the Guadalupe Mountains

Botanists are studying the genetics of specimens collected half a century ago to learn how plants respond to climate change in the Guadalupe Mountains

Peer-Reviewed Publication

BOTANICAL SOCIETY OF AMERICA

 

IMAGE: THESE SPECIMENS OF TORREY’S JOINTFIR (EPHEDRA TORREYANA) AND BIENNIAL WOOLLYWHITE (HYMENOPAPPIS BIENNIS) WERE COLLECTED IN THE GUADALUPE MOUNTAINS OF TEXAS IN THE 1970S AND ARE CURRENTLY BEING STORED IN THE E.L. REED HERBARIUM AT TEXAS TECH UNIVERSITY, WHERE ANY RESEARCHER CAN REQUEST ACCESS TO STUDY THEM. view more 

CREDIT: PHOTO COURTESY OF TEXAS TECH E.L. REED HERBARIUM, LICENSED UNDER CREATIVE COMMONS.

Botanists at Texas Tech University recently tested a new genetic resource on plants from the Guadalupe Mountains, a region that boasts some of the most diverse ecosystems in Texas. Called Angiosperms353, the resource has the potential to help unravel the 500-million-year history of land plants while also providing a conservation roadmap to protect vulnerable species into the future.

It was with this last goal in mind that researchers sequenced the DNA of plant specimens collected nearly 50 years ago, when the Guadalupe Mountains were first designated a national park. The researchers published their results in the journal Applications in Plant Sciences.

“By comparing them to modern specimens, we can try to figure out exactly how rising temperatures and changes in weather and land use have affected these populations,” said lead author Madeline Slimp, who conducted the study while completing her bachelor’s degree at Texas Tech.

 

The Guadalupe Mountains are a hotbed of genetic diversity

Located in the northern spur of the Chihuahuan Desert, the Guadalupe Mountains are the remains of an ancient coral reef and limestone seafloor that was uplifted by tectonic instability in the region beginning about 20 million years ago. Within that span of time, the peaks have been thrust up to over 5,000 feet above the surrounding sand dunes.

This abrupt change in elevation allows a number of rare plant ecosystems to thrive in the desert, including temperate forests, grasslands, dry slopes of cactus and creosote, and peaks crowned with firs and pine. Their distance from other ranges, such as the Rockies to the north or the Apache Mountains to the south, has also meant that many of the native plants have evolved there in isolation and can be found nowhere else on Earth.

“It’s by nature extremely diverse,” Slimp said. “There are a lot of endemic and unique specimens in that area as well as species that are at their furthest northern extent.”

 

Botanists create a benchmark for future conservation efforts

Prior to its designation as a national park, the area had been used for agriculture, with a large portion dedicated to goat livestock that heavily grazed on the rare and endemic plants.

When the land was granted protected status in 1966, biologists jumped at the opportunity to study the native flora and fauna, including two botanists who compiled an extensive inventory of everything that grew in the park. Over the course of several years, they took copious notes and collected over 3,000 specimens, with multiple individuals of the same species, that they stored for later use.

Now, nearly 50 years later, researchers are returning to the Guadalupe collections with the goal of seeing how genetic diversity has changed over time in the region.

“We can learn something about the health of a population from the amount of genetic diversity there is within a species,” said Matt Johnson, director of the E.L. Reed Herbarium at Texas Tech and senior author on the study. “This can tell us whether a particular species is in peril.”

Obtaining DNA from old plant material isn’t always easy, however; as soon as a cell dies, its contents begin to break down, which includes DNA. Collectors and curators slow down this process of degradation by keeping specimens in herbaria, repositories where plants are stored in cool, dry conditions. But ultimately, they can only forestall the inevitable.

But recent advances in technology are allowing scientists to reliably retrieve DNA strands from old specimens. Researchers now regularly sample from plants collected more than 100 years ago, before anyone fully understood what DNA was or how it carried genetic information from one generation to the next.

 

Preserved DNA offers a glimpse into the past

The techniques used in the new Angiosperms353 genetic toolkit are particularly well-suited for sifting through old, degraded DNA, and the meticulously curated Guadalupe collection presented the perfect opportunity for Slimp and her colleagues to give it a test run.

To get the widest snapshot of diversity, they strategically chose key specimens from among the more than 1,000 plant species that grow in the Guadalupe Mountains. “We chose 24 species that represent a large breadth of natural history types, including grasses, trees, shrubs, and forbs,” Slimp said.

Although the study was meant only to provide a preliminary look at past ecosystems within the park, the results of their DNA analyses revealed patterns that would have been impossible to determine from plant surveys or abundance estimates alone.

Species with small distributions, for example, are often the first to be regarded for conservation efforts. But several species restricted to areas in and around the Guadalupe Mountains, such as sandpaper oak, great sage, and mock orange, were revealed to have had surprisingly high amounts of genetic diversity. All things being equal, the more genetic diversity a species has, the more likely it will be able to adapt to changes in climate over long periods of time.

But the isolated environments of the Guadalupe Mountains, ringed on all sides by the Chihuahuan Desert, may act as a constricting vise on future plant populations. As the Earth’s climate becomes warmer, plants move up in elevation, offsetting the increase in temperature, Slimp said.

As a result, an increasing number of plants compete for limited space, and those already adapted to environments at the highest elevations are left stranded. “They may have nowhere to go once it gets too hot,” Slimp said. “We might lose a ton of biodiversity in this area.”

Now that Slimp and her colleagues have established a baseline for comparison, their next step will be sequencing the DNA of plants currently growing in the mountains to assess how the genetic health of their populations has changed during the intervening years.

“With these results, we can go back and resample the park using Angiosperms353,” Slimp said. “By better understanding what we currently have, we can get an idea of what we need to do in the future to conserve these species.”

 

Citation: Slimp, M., L. D. Williams, H. Hale, and M. G. Johnson. 2021. On the potential of Angiosperms353 for population genomic studies. Applications in Plant Sciences 9(7): e11419. https://doi.org/10.1002/aps3.11419

Applications in Plant Sciences (APPS) is a monthly, peer-reviewed, open access journal focusing on new tools, technologies, and protocols in all areas of the plant sciences. It is published by the Botanical Society of America (www.botany.org), a nonprofit membership society with a mission to promote botany, the field of basic science dealing with the study and inquiry into the form, function, development, diversity, reproduction, evolution, and uses of plants and their interactions within the biosphere. APPS is available as part of the Wiley Online Library (https://onlinelibrary.wiley.com/journal/21680450).

For further information, please contact the APPS staff at apps@botany.org.

Scrubland of the Chihuahuan Desert (IMAGE)

BOTANICAL SOCIETY OF AMERICA

CAPTION

The Chihuahuan Desert runs along the foothills of the Guadalupe Mountains, creating a barrier to dispersal to many of the plants in the National Park that require large amounts of precipitation or a near-constant source of water, such as streams and rivers, to survive.

CREDIT

Photo courtesy of Matt Johnson.

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JOURNAL

Applications in Plant Sciences

DOI

10.1002/aps3.11419

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

On the potential of Angiosperms353 for population genomic studies

ARTICLE PUBLICATION DATE

18-May-2021