Research project analyzes medical, nutritional and environmental applications of new Antarctic bacteria
Discovered by Uruguayan scientists in 2013, two psychrophilic (cold-adapted) species have been experimented with since 2018 by a partnership between IIBCE in Montevideo and the University of São Paulo in Brazil.
Peer-Reviewed PublicationIMAGE: RESEARCH PROJECT ANALYZES MEDICAL, NUTRITIONAL AND ENVIRONMENTAL APPLICATIONS view more
CREDIT: INSTITUTO DE INVESTIGACIONES BIOLÓGICAS CLEMENTE ESTABLE
A scientific collaboration between the University of São Paulo (USP) in Ribeirão Preto, Brazil, and Clemente Estable Institute of Biological Research (IIBCE) in Montevideo, Uruguay, is experimenting with two new bacteria discovered in the Antarctic ten years ago, in order to verify the possibility of applications in healthcare, food processing and environmental rehabilitation.
An article describing part of the results appeared in the March issue of the journal ACS Synthetic Biology, a publication of the American Chemical Society.
The use of bacteria in biotechnology offers many potential benefits for human beings and the planet, including the absence of toxic waste and lack of dependence on fossil energy sources. Bacteria are microscopic organisms that have the ability to adapt to various environments and perform a range of important functions. Bacteria retrieved from terrestrial extremes have even more interesting physiological characteristics. Antarctica is the coldest continent, with temperatures ranging from -10 °C to -60 °C in winter and from -5 °C to -20 °C in summer.
Bacteria with cold-adapted enzymes are known as psychrophiles. Enzymes are proteins that catalyze specific chemical reactions. The enzymes produced by psychrophiles are very important to biotechnological processes because they remain highly active even at low temperatures. As a result, they are less expensive and more sustainable than enzymes produced by bacteria in temperate environments.
“Bacteria isolated from the environment are often very hard to ‘domesticate’ with a view to using their enzymes. We studied two bacteria belonging to the genus Pseudomonas isolated from sediment in the Antarctic. They’re both new species that have never been described before. We set out to see if we could take advantage of their metabolism with our gene editing tools and succeeded in establishing the correct functioning of several plasmids in these two bacteria, facilitating their use for expression of psychrophilic enzymes in biotech applications,” said María Eugenia Guazzaroni, last author of the article and a professor in the Biology Department of the Ribeirão Preto School of Philosophy, Sciences and Letters (FFCLRP-USP). Her research is supported by FAPESP.
Applications
Bacterial plasmids are small DNA molecules commonly used in bacterial cloning. Expression plasmids are used to produce specific proteins. The plasmid is introduced into a cell, where it replicates, and the protein is expressed by its DNA.
Expression plasmids are widely used in scientific research and by pharmaceutical and biotech firms to produce large quantities of specific recombinant proteins for the development of medical therapies with hormones or antibodies.
Psychrophilic enzymes can also be used to produce refrigerated foods such as ice cream and yogurt with enhanced quality and texture. Yet another application involves additives in detergent and washing powder to improve the efficacy of stain and dirt removal. These enzymes function at comparatively low temperatures and can therefore be used for washing laundry in cold water, economizing energy. They also improve the quality of detergent and washing powder, so that clothes and other items made of fabric are less damaged and last longer.
Psychrophilic enzymes can also be used in bioremediation to remove pollutants from cold environments such as the Antarctic.
Cross-border collaboration
The study was conducted in collaboration with Uruguayan scientists who discovered the new bacteria in 2012 in the Antarctic and have been working with the Ribeirão Preto group since 2018. “Vanesa Amarelle, a co-author of the article, visited us as a postdoctoral fellow with a scholarship for training mobility at research institutes abroad in priority areas awarded by Uruguay’s National Research and Innovation Agency [ANII] in 2018,” said Guazzaroni, who has a PhD in biochemistry and molecular biology from Zaidín Experiment Station (EEZ) in Granada, run by Spain’s National Research Council (CSIC), with postdoctoral qualifications in environmental metagenomics and functional metagenomics of extreme environments, also earned in Spain, as well as postdoctoral studies at FFCLRP-USP.
Besides Guazzaroni and Amarelle, the other co-authors of the article are Diego M. Roldán and Elena Fabiano, both of whom are affiliated with IIBCE’s Department of Microbial Biochemistry and Genomics.
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.
ARTICLE TITLE
Synthetic Biology Toolbox for Antarctic Pseudomonas sp. Strains: Toward a Psychrophilic Nonmodel Chassis for Function-Driven Metagenomics
Little-known microbes could help predict climate tipping points
Rising temperatures could push ocean plankton and other single-celled creatures toward a carbon tipping point that fuels more warming. But new research shows it’s also possible to detect early distress signals before they get there.
Peer-Reviewed PublicationIMAGE: FOUND IN LAKES AND RIVERS WORLDWIDE, SINGLE-CELLED CREATURES LIKE THESE PARAMECIUM BURSARIA CAN BOTH EAT AND PHOTOSYNTHESIZE. MICROBES LIKE THIS PLAY A DOUBLE ROLE IN CLIMATE CHANGE, RELEASING OR ABSORBING CARBON DIOXIDE -- THE HEAT-TRAPPING GREENHOUSE GAS THAT IS THE PRIMARY DRIVER OF WARMING -- DEPENDING ON WHETHER THEY RELY ON AN ANIMAL-LIKE LIFESTYLE OR A PLANT-LIKE LIFESTYLE. view more
CREDIT: DANIEL J. WIECZYNSKI, DUKE UNIVERSITY
DURHAM, N.C. -- Researchers studying a group of widespread but often overlooked microbes have identified a climate feedback loop that could accelerate climate change. But it’s not all bad news: this one comes with an early warning signal.
Using a computer simulation, a team of scientists from Duke University and the University of California, Santa Barbara, showed that most of the world’s ocean plankton and many other single-celled creatures in lakes, peatlands and other ecosystems could cross a threshold where instead of soaking up carbon dioxide, they start doing the opposite. That’s because of how warming affects their metabolism.
Because carbon dioxide is a greenhouse gas, that in turn could drive up temperatures further -- a positive feedback loop that could lead to runaway change, where small amounts of warming have an outsized impact.
But by carefully monitoring the abundances of these organisms, we might be able to anticipate the tipping point before it gets here, the researchers report in a study published June 1 in the journal Functional Ecology.
In the new study, researchers focused on a group of tiny organisms called mixotrophs, so named because they mix up two modes of metabolism: they can photosynthesize like a plant or hunt food like an animal, depending on conditions.
“They're like the Venus fly traps of the microbial world,” said first author Daniel Wieczynski, a postdoctoral associate at Duke.
During photosynthesis, they soak up carbon dioxide, a heat-trapping greenhouse gas. And when they eat, they release carbon dioxide. These versatile organisms aren’t considered in most models of global warming, yet they play an important role in regulating climate, said senior author Jean P. Gibert of Duke.
Most of the plankton in the ocean -- things like diatoms, dinoflagellates -- are mixotrophs. They’re also common in lakes, peatlands, in damp soils and beneath fallen leaves.
“If you were to go to the nearest pond or lake and scoop a cup of water and put it under a microscope, you’d likely find thousands or even millions of mixotrophic microbes swimming around,” Wieczynski said.
“Because mixotrophs can both capture and emit carbon dioxide, they're like ‘switches’ that could either help reduce climate change or make it worse,” said co-author Holly Moeller, an assistant professor at the University of California, Santa Barbara.
To understand how these impacts might scale up, the researchers developed a mathematical model to predict how mixotrophs might shift between different modes of metabolism as the climate continues to warm.
The researchers ran their models using a 4-degree span of temperatures, from 19 to 23 degrees Celsius (66-73 degrees Fahrenheit). Global temperatures are likely to surge 1.5 degrees Celsius above pre-industrial levels within the next five years, and are on pace to breach 2 to 4 degrees before the end of this century.
The analysis showed that the warmer it gets, the more mixotrophs rely on eating food rather than making their own via photosynthesis. As they do, they shift the balance between carbon in and carbon out.
The models suggest that, eventually, we could see these microbes reach a tipping point -- a threshold beyond which they suddenly flip from carbon sink to carbon source, having a net warming effect instead of a cooling one.
This tipping point is hard to undo. Once they cross that threshold, it would take significant cooling -- more than one degree Celsius -- to restore their cooling effects, the findings suggest.
But it’s not all bad news, the researchers said. Their results also suggest that it may be possible to spot these shifts in advance, if we watch out for changes in mixotroph abundance over time.
“Right before a tipping point, their abundances suddenly start to fluctuate wildly,” Wieczynski said. “If you went out in nature and you saw a sudden change from relatively steady abundances to rapid fluctuations, you would know it’s coming.”
Whether the early warning signal is detectable, however, may depend on another key factor revealed by the study: nutrient pollution.
Discharges from wastewater treatment facilities and runoff from farms and lawns laced with chemical fertilizers and animal waste can send nutrients like nitrate and phosphate into lakes and streams and coastal waters.
When Wieczynski and his colleagues included higher amounts of such nutrients in their models, they found that the range of temperatures over which the telltale fluctuations occur starts to shrink until eventually the signal disappears and the tipping point arrives with no apparent warning.
The predictions of the model still need to be verified with real-world observations, but they “highlight the value of investing in early detection,” Moeller said.
“Tipping points can be short-lived, and thus hard to catch,” Gibert said. “This paper provides us with a search image, something to look out for, and makes those tipping points -- as fleeting as they may be -- more likely to be found.”
This research was supported by grants from the Simons Foundation (689265), the National Science Foundation (1851194), and the U.S. Department of Energy (DE-SC0020362).
CITATION: "Mixotrophic Microbes Create Carbon Tipping Points Under Warming," Daniel J. Wieczynski, Holly V. Moeller and Jean P. Gibert. Functional Ecology, May 23, 2023. DOI: 10.1111/1365-2435.14350
# # #
JOURNAL
Functional Ecology
METHOD OF RESEARCH
Computational simulation/modeling
SUBJECT OF RESEARCH
Cells
ARTICLE TITLE
Mixotrophic Microbes Create Carbon Tipping Points Under Warming
ARTICLE PUBLICATION DATE
1-Jun-2023
Warming climate could turn ocean plankton microbes into carbon emitters
Peer-Reviewed PublicationVIDEO: THE MIXOTROPHIC PROTIST PARAMECIUM BURSARIA CAN EAT BACTERIA OR USE PHOTOSYNTHESIS TO GET ENERGY AND CARBON. PHOTOSYNTHESIS OCCURS INSIDE THE ENDOSYMBIOTIC CHLORELLA ALGAE (GREEN SPHERES) THAT LIVE INSIDE P BURSARIA CELLS. view more
CREDIT: DANIEL WIECZYNSKI
New research finds that a warming climate could flip globally abundant microbial communities from carbon sinks to carbon emitters, potentially triggering climate change tipping points. The findings are published in the British Ecological Society journal Functional Ecology.
- New research finds that under a warming climate, ocean plankton and other single-celled organisms, known as mixotrophic microbes – can switch from being carbon sinks to carbon emitters.
- The research also finds that changes in the behaviour of these organisms right before they switch can act as an early warning signal for climate change tipping points.
- However, increases in nutrient levels in the environment, such as nitrogen from agricultural runoff, can mute these warning signals.
Carbon sinks to carbon emitters
Mixotrophic microbes are organisms that can switch between photosynthesising like plants (absorbing carbon dioxide) and eating like animals (releasing carbon dioxide). They are globally abundant, commonly found in freshwater and marine environments, and estimated to make up the majority of marine plankton.
By developing a computer simulation that modelled how mixotrophic microbes acquire energy in response to warming, researchers at Duke University and the University of California Santa Barbara, have found that under warming conditions, mixotrophic microbes shift from being carbon sinks to carbon emitters.
The findings mean that as temperatures increase, these highly abundant microbial communities could change from having a net cooling effect on the planet to a net warming effect.
Dr Daniel Wieczynski of Duke University and lead author of the study said: “Our findings reveal mixotrophic microbes are much more important players in ecosystem responses to climate change than previously thought. By converting microbial communities to net carbon dioxide sources in response to warming, mixotrophs could further accelerate warming by creating a positive feedback loop between the biosphere and the atmosphere.”
Dr Holly Moeller of University of California Santa Barbara and co-author of the study added: “Because mixotrophs can both capture and emit carbon dioxide, they are like ‘switches’ that could either help reduce climate change or make it worse. These bugs are tiny, but their impacts can really scale up. We need models like this to understand how.”
Dr Jean-Philippe Gibert of Duke University and another co-author of the study said: “State-of-the-art predictive models of long-term climate change currently only account for microbial action in an extremely reductive, partial, or sometimes plain wrong fashion. Research like this is therefore much needed to improve our broader understanding of the biotic controls on Earth's atmospheric processes.”
An early warning system
The researchers’ model also revealed that right before mixotrophic microbe communities switch to emitting carbon dioxide, their abundance starts to fluctuate wildly. These changes could be detected in nature by monitoring mixotrophic microbe abundance and offers hope that these microbes could act as early warning signals for climate change tipping points.
Dr Wieczynski said: “These microbes may act as early indicators of the catastrophic effects of rapid climate change, which is especially important in ecosystems that are currently major carbon sinks like peatlands, where mixotrophs are highly abundant.”
However, the researchers also found these early warning signals can be muted by increases of nutrients like Nitrogen to the environment, typically caused by run off from agriculture and wastewater treatment facilities.
When higher amounts of such nutrients were included in the simulations, the researchers found that the range of temperatures over which the tell-tale fluctuations occur starts to shrink until eventually the signal disappears and the tipping point arrives with no apparent warning.
“Detecting these warning signs is going to be challenging. Especially if they're getting more subtle with nutrient pollution.” Said Dr Moeller. “However, the implications of missing them are huge. We could wind up with ecosystems in a much less desirable state, adding greenhouse gases to the atmosphere instead of removing them.”
In the study, the researchers ran simulations using a 4-degree span of temperatures, from 19 to 23 degrees Celsius. Global temperatures are likely to surge 1.5 degrees Celsius above pre-industrial levels within the next five years, and are on pace to breach 2 to 4 degrees before the end of this century.
The researchers caution that the mathematical modelling used in the study draws on limited empirical evidence to investigate the effects of warming on microbial communities. Dr Wieczynski said: “Although models are powerful tools theoretical results must ultimately be tested empirically. We strongly advocate for further experimental and observational testing of our results.”
-ENDS-
JOURNAL
Functional Ecology
METHOD OF RESEARCH
Computational simulation/modeling
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Mixotrophic microbes create carbon tipping points under warming
ARTICLE PUBLICATION DATE
1-Jun-2023
