Food insecurity is significant among inhabitants of the region affected by the Belo Monte dam in Brazil

A study of 500 households in Altamira, a city near the dam in Pará state, showed that 61% experienced food insecurity

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A PARTIAL VIEW OF THE CITY OF ALTAMIRA, PARÁ, IN AUGUST 2022, WITH THE XINGU RIVER IN THE BACKGROUND 

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CREDIT: IGOR CAVALLINI JOHANSEN

The social and environmental impact of the Belo Monte dam and hydroelectric power plant in Pará state, Brazil, has been called a “disaster” by researchers, environmentalists and several media outlets. The damage has again been highlighted recently in an inspection report issued by the Brazilian Institute for the Environment and Renewable Natural Resources (IBAMA), an agency of the Ministry for the Environment and Climate Change. The inspectors detected silting and erosion of the Xingu River, obstacles to river navigation, a significant increase in tree mortality, and the impossibility of reproduction for several fish species, as well as disruptions to the way of life of Indigenous and river-dwelling communities.

A new study conducted with FAPESP’s support focuses specifically on food insecurity in Altamira, which is the city with the largest population in the region and has been dramatically affected by the construction of Belo Monte. Because of the megaproject, Altamira became a hub for the distribution of goods, services and the logistics essential to the construction process, with a significant impact on its population. 

Construction took place between 2011 and 2015, causing the city’s population to grow without adequate planning to assure the provision of services to residents and migrants looking for work. The shock made Altamira one of Brazil’s most violent cities. Although its population has declined since the dam was completed, the 2022 census recorded 126,279 inhabitants, 27.46% more than in 2010, when the previous census was conducted. This growth rate compares with 6.46% for Brazil’s total population growth in the same period.

The study, published in the International Journal of Environmental Research and Public Health, shows that 61% of Altamira’s households experienced some level of food insecurity and malnutrition in 2022, when the data was collected. 

“We conducted the survey in July 2022, seven years after construction ended, visiting 500 households selected as representative of the city’s socioeconomic strata and geographic areas. The scale used to measure household food insecurity is divided into three categories. We found the worst food insecurity in the poorest group, where heads of household had low levels of educational attainment and unemployment was high. In addition, the households with severe food insecurity had more members. Families displaced by the dam and resettled elsewhere also experienced severe food insecurity,” said Igor Cavallini Johansen, first author of the article. Johansen is a demographer and a postdoctoral researcher affiliated with the State University of Campinas’s Center for Environmental Studies (NEPAM-UNICAMP) in São Paulo state.

Unlike other studies of food insecurity in the context of hydroelectric developments in Brazil, this one used the Brazilian Household Food Insecurity Scale, known by the Portuguese-language acronym EBIA, Johansen said, explaining that the scale is based on a scientifically validated methodology for measuring access to sufficient food of adequate quality. 

“The survey included a questionnaire with eight standardized items. The responses were scored using the EBIA scale to arrive at a classification of food insecurity for each household in the sample,” he said.

The households were classified into the following categories: (1) food security (adequate food quantity and quality); (2) mild food insecurity (food quality impaired and uncertainty regarding future food availability; (3) moderate food insecurity (inadequate diet, food becoming scarce within the household, children prioritized over adults); (4) severe food insecurity (insufficient food for all household members).

“We formulated three hypotheses: (1) households were affected by a range of factors that together produced food insecurity; (2) poverty played a key role, and the most affected groups were those who had been forced to leave their homes and had been resettled in purpose-built housing projects, known as RUCs; and (3) besides the impact of the dam, the problem was made worse by the COVID-19 pandemic,” Johansen said.

The survey also took into account several socioeconomic variables as correlates of food insecurity, such as a wealth index (poorest, intermediate, least poor) considering the characteristics of the home, ownership of vehicles and appliances, etc.; whether respondents were monthly handouts from the Bolsa Família conditional cash transfer program; whether they had officially declared themselves affected by the dam; whether they lived in an RUC; the number of household members and over-sixties; and the head of household’s gender, skin color, age, marital status, educational attainment and employment status. 

“All three hypotheses were confirmed. Predictably, the various factors correlated with each other: the impact of the dam’s construction significantly increased the probability that household members lived in an RUC, and this increased the likelihood that a family was poor, which in turn entailed a risk of food insecurity,” Johansen said. “Access to food of the desired quantity and quality became more difficult for 69.7% of the households after construction of the dam was completed in 2015.” About half of these households (52.5%) said it had already been difficult before the pandemic, and the rest blamed the pandemic for the worsening of food insecurity since then.

“We also found that households with one or more members aged 60 and over experienced less food insecurity. This can be attributed to the contribution of old-age pensions to the household income, potentially reducing their exposure to poverty and hence to food insecurity,” he noted.

The lack of a survey conducted before the dam’s construction and based on the EBIA scale was unfortunate, Johansen added, as this could have been compared with the results obtained after its construction. “In any event, it was a shock to find that 61% of the households experienced food insecurity when the consortium that built the dam claimed to have invested BRL 6.5 billion, or about USD 1.3 billion, in social, environmental and sustainability-related measures in the region between 2016 and 2022. What was all that money used for?” he said.

The negative impact of Belo Monte is not an isolated case. Several other megaprojects implemented in the Amazon have also had significant social and environmental side effects. Another study conducted by the same research group and led by Caroline Arantes, a professor at West Virginia University in the United States showed that fishing communities lost production and income after construction of the Santo Antônio and Jirau hydroelectric projects in Porto Velho, Rondônia state. The communities were forced to adapt their fishing strategies and find other ways to earn a living in response to the impact of the dams. Household consumption of fish diminished significantly as a result. “These communities had always had fish meals every day, but after the dams were built they were able to do so only once or twice a week, if not less often,” Johansen said. The study in question is published in the Journal of Environmental Management.

Another prior study, in this case focusing on a fishing community on the Xingu River after construction of Belo Monte, showed that fish became scarce and food in general became more expensive in the region. An article on this study is published in the journal Human Ecology.

All these studies involved contributions by Professor Emilio F. Moran, principal investigator for the project “After hydropower dams: social and environmental processes that occur after the construction of Belo Monte, Jirau and Santo Antônio in Brazilian Amazon”, and supported by FAPESP via the São Paulo Excellence Chair program (SPEC). 

In addition to this grant, the study was supported by a postdoctoral scholarship awarded to Johansen, and a postdoctoral scholarship awarded to Vanessa Cristine e Souza Reis, also a member of the research group.

About São Paulo Research Foundation (FAPESP)

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

 

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JOURNAL

International Journal of Environmental Research and Public Health

DOI

10.3390/ijerph21020155 

ARTICLE TITLE

Poverty–Food Insecurity Nexus in the Post-Construction Context of a Large Hydropower Dam in the Brazilian Amazon

 

Large Hadron Collider experiment zeroes in on magnetic monopoles

by Ana Lopes, CERN

The MoEDAL detector. Credit: CERN

The late physicist Joseph Polchinski once said the existence of magnetic monopoles is "one of the safest bets that one can make about physics not yet seen." In its quest for these particles, which have a magnetic charge and are predicted by several theories that extend the Standard Model, the MoEDAL collaboration at the Large Hadron Collider (LHC) has not yet proven Polchinski right, but its latest findings mark a significant stride forward.

The results, reported in two papers posted on the arXiv preprint server, considerably narrow the search window for these hypothetical particles.

At the LHC, pairs of magnetic monopoles could be produced in interactions between protons or heavy ions. In collisions between protons, they could be formed from a single virtual photon (the Drell–Yan mechanism) or the fusion of two virtual photons (the photon-fusion mechanism). Pairs of magnetic monopoles could also be produced from the vacuum in the enormous magnetic fields created in near-miss heavy-ion collisions, through a process called the Schwinger mechanism.

Since it started taking data in 2012, MoEDAL has achieved several firsts, including conducting the first searches at the LHC for magnetic monopoles produced via the photon-fusion mechanism and through the Schwinger mechanism.

In the first of its latest studies, the MoEDAL collaboration sought monopoles and high-electric-charge objects (HECOs) produced via the Drell–Yan and photon-fusion mechanisms. The search was based on proton–proton collision data collected during Run 2 of the LHC, using the full MoEDAL detector for the first time.

The full detector comprises two main systems sensitive to magnetic monopoles, HECOs and other highly ionizing hypothetical particles. The first can permanently register the tracks of magnetic monopoles and HECOs, with no background signals from Standard Model particles. These tracks are measured using optical scanning microscopes at INFN Bologna.

The second system consists of roughly a ton of trapping volumes designed to capture magnetic monopoles. These trapping volumes—which make MoEDAL the only collider experiment in the world that can definitively and directly identify the magnetic charge of magnetic monopoles—are scanned at ETH Zurich using a special type of magnetometer called a SQUID to look for any trapped monopoles they may contain.

In their latest scanning of the trapping volumes, the MoEDAL team found no magnetic monopoles or HECOs, but it set bounds on the mass and production rate of these particles for different values of particle spin, an intrinsic form of angular momentum.

For magnetic monopoles, the mass bounds were set for magnetic charges from 1 to 10 times the fundamental unit of magnetic charge, the Dirac charge (gD), and the existence of monopoles with masses as high as about 3.9 trillion electronvolts (TeV) was excluded.

For HECOs, the mass limits were established for electric charges from 5e to 350e, where e is the electron charge, and the existence of HECOs with masses ranging up to 3.4 TeV was ruled out.

"MoEDAL's search reach for both monopoles and HECOs allows the collaboration to survey a huge swathe of the theoretical 'discovery space' for these hypothetical particles," says MoEDAL spokesperson James Pinfold.

In its second latest study, the MoEDAL team concentrated on the search for monopoles produced via the Schwinger mechanism in heavy-ion collision data taken during Run 1 of the LHC. In a unique endeavor, it scanned a decommissioned section of the CMS experiment beam pipe, instead of the MoEDAL detector's trapping volumes, in search of trapped monopoles.

Once again, the team found no monopoles, but it set the strongest-to-date mass limits on Schwinger monopoles with a charge between 2gD and 45gD, ruling out the existence of monopoles with masses of up to 80 GeV.

"The vital importance of the Schwinger mechanism is that the production of composite monopoles is not suppressed compared to that of elementary ones, as is the case with the Drell–Yan and photon-fusion processes," explains Pinfold. "Thus, if monopoles are composite particles, this and our previous Schwinger-monopole search may have been the first-ever chances to observe them."

The MoEDAL detector will soon be joined by the MoEDAL Apparatus for Penetrating Particles, MAPP for short, which will allow the experiment to cast an even broader net in the search for new particles.

More information: Search for Highly-Ionizing Particles in pp Collisions During LHC Run-2 Using the Full MoEDAL Detector, arXiv (2023). DOI: 10.48550/arxiv.2311.06509

B. Acharya et al, MoEDAL search in the CMS beam pipe for magnetic monopoles produced via the Schwinger effect, arXiv (2024). DOI: 10.48550/arxiv.2402.15682

Journal information: arXiv 

Provided by CERN ATLAS experiment places some of the tightest limits yet on magnetic monopoles

 

Ridesourcing platforms thrive on socio-economic inequality, say researchers

by Delft University of Technology

Credit: Pixabay/CC0 Public Domain

Platforms that offer rides to passengers, such as Uber and DiDi, thrive on socio-economic inequality. By modeling the behavior of passengers and self-employed drivers, researchers of TU Delft simulated the market for ridesourcing platforms, evaluating a broad spectrum of (in)equality levels in societies.

It explains why in some cities ridesourcing services can be big players in the mobility system, while in other cities they don't get off the ground. The research was published in Scientific Reports recently.

What if everybody had the same income? Or what if almost all money was held by one person? With these extremes of (in)equality, TU Delft researchers simulated the market for ridesourcing platforms, such as Uber or DiDi. They uncovered a compelling relationship between socio-economic inequality and the market share of the platforms. Oded Cats, professor of Passenger Transport Systems said, "These extremes help contextualize real-world dynamics, where all societies worldwide fall somewhere in between."

To move towards a sustainable urban mobility system, new designs prioritize the enhancement of public transport. Understanding how to reinforce public transit and improve access to public transport hubs for passengers is crucial.

"In cities like Amsterdam, with relatively low inequality, short travel distances and well-established bicycle and public transport networks, Uber is unlikely to flourish," researcher Arjan de Ruijter explains. "Therefore, transport authorities in such cities should rather focus on providing shared bikes and scooters to improve station access."

Conversely, in cities marked by significant inequality, like Johannesburg or Rio de Janeiro, Uber-like ridesourcing platforms thrive. Various explanations, taking into account driver's and passenger's behavior, emerge in the study. The platform capitalizes on a workforce willing to accept lower wages, leading to a service with limited waiting times for passengers. Moreover, it acknowledges the demand for mobility on demand among the affluent segments of unequal societies, willing to pay for a premium-like service.

These insights can explain and predict the potential dominance of Uber-like services in the design of a mobility system. Adding to that, it provides guidance for designing inclusive mobility systems and assessing the necessity for regulatory measures.

De Ruijter observed how these platforms adapt their strategies based on inequality. "In a society with high inequality, companies can charge higher commissions to drivers, as drivers have limited alternative labor opportunities."

Cats adds, "On the other hand, in societies with low inequality, all else being equal, pricing strategies must attract more selective job seekers, resulting in lower commission rates." This illustrates the interplay between socio-economic factors and the viability of ridesourcing platforms.

Because of the lack of data on ridesourcing market shares in different cities, the researchers decided to model the behavior of the key players in the market and experiment with different market settings.

Their model may also be useful in investigating inequality effects in meal and grocery delivery markets, provided by platforms such as Just Eat Takeaway and Getir. These service-platforms also seem to flourish on a group of relatively affluent users willing to pay for service, and a group of drivers willing to do low-wage work.

More information: Arjan de Ruijter et al, Ridesourcing platforms thrive on socio-economic inequality, Scientific Reports (2024). DOI: 10.1038/s41598-024-57540-x

Journal information: Scientific Reports 

Provided by Delft University of Technology How does ridesourcing substitute for public transit network?

 

Did Vesuvius bury the home of the first Roman emperor?

by University of Tokyo

A haunting sight at the archaeological site. The face of a statue of the god Dionysus as it's 

painstakingly chipped away from and brushed free of millennia of built-up deposits. 

Credit: 2024 Institute for Advanced Global Studies CC-BY-ND

A group of archaeologists, led by researchers from the University of Tokyo, announce the discovery of a part of a Roman villa built before the middle of the first century. This villa, near the town of Nola in southwestern Italy's Campania region, was found beneath a more recent, but still ancient building from the 2nd century.

Specific findings at the site, buried by multiple eruptions of Mount Vesuvius, suggest it might have been the home of Gaius Julius Caesar Augustus (Octavian), the founding emperor of the Roman Empire, as they coincide with contemporary writings by known Roman writers Tacitus, Suetonius, and Dio Cassius.

This excavation is also significant as it was previously thought that only areas to the south of Vesuvius, famously the ancient Roman cities of Pompeii and Herculaneum, were heavily damaged, but this villa is located in the valley of Somma Vesuviana to the north.

In 1929, a farmer discovered, by accident, part of an abandoned building buried in a field. Archaeologists set to work excavating the site to reveal an extravagant villa that strongly hinted at being the residence of Augustus. However, the financial condition at that time impeded further exploration of the site.

This situation changed in 2002 when the University of Tokyo began an interdisciplinary project, in collaboration with local archaeologists, to fully excavate the villa and learn about this potentially significant area. Since then, many Roman objects, beautiful marble statues—including two pieces fit enough to be displayed in a museum—a huge building with various rooms, wall paintings, stucco reliefs and mosaics have been revealed.

An archaeologist stands next to a pillar, showing the magnitude of the ancient dwelling. 

Credit: 2024 Institute for Advanced Global Studies CC-BY-ND

"Excavations around Mount Vesuvius have been ongoing since the 18th century. It was known that beneath the ash and debris from the biggest eruption in A.D. 79, various Roman artifacts lay buried," said Kohei Sugiyama, an archaeologist from the Institute for Advanced Global Studies at the University of Tokyo.

"Most exploration related to that are focused on regions to the south of the volcano as that is where the majority of ejecta fell, and damage was suffered. For over 20 years, we have excavated large sections of the villa and have recently uncovered some previously unknown rooms and other architectural elements.

"Using radiocarbon dating, and with help from volcanologists to perform extra analysis, we determined that these newly discovered sections are buried under volcanic material from the A.D. 79 eruption."

Ejected volcanic rocks from the A.D. 79 eruption of Mount Vesuvius. 

Credit: 2024 Institute for Advanced Global Studies CC-BY-ND

Pots buried under ash and other pyroclastic materials of the A.D. 79 eruption of Mount Vesuvius give clues about the levels of volcanic damage to the villa. 

Credit: 2024 Institute for Advanced Global Studies CC-BY-ND

Sugiyama and his team revealed significant destruction in the northern area of Mount Vesuvius, including damage from lava flows and pyroclastic surges, the big explosions you see people running from in movies about volcanoes.

At the site of the villa during the 2002 excavations, volcanologists in the team revealed the upper levels of the building were constructed by the mid-second century, and that the villa was built upon some of the partially obscured structures that came before it.

This finding indicates the resilience and rebuilding efforts of the people following the disaster of A.D. 79 in the area of Somma Vesuviana, unlike Pompeii, where the thick layers of volcanic ash and pyroclastic flows left the city abandoned for many centuries.

"This kind of investigation is important for several reasons," said Sugiyama. "Not only does it connect physical evidence with Augustus, who is mainly known through historic writings, but it also tells us about the local economy and society in that region at that time, which may have been more prosperous and significant than was previously thought.

"Learning about how ancient people recovered from disasters could inform how we plan for such things today. It's challenging to carry out this kind of archaeology due to the heavy machinery needed to dig down to 15 meters and move large boulders, and of course funding can often be an issue."

Provided by University of Tokyo Harnessed horse unearthed in ancient stable near Pompeii

 

Florida dolphin found with highly pathogenic avian flu: Report

by University of Florida

Credit: Pixabay/CC0 Public Domain

The case of a Florida bottlenose dolphin found with highly pathogenic avian influenza virus, or HPAIV—a discovery made by University of Florida researchers in collaboration with multiple other agencies and one of the first reports of a constantly growing list of mammals affected by this virus—has been published in Communications Biology

The report documents the discovery, the first finding of HPAIV in a cetacean in North America, from the initial response by UF's Marine Animal Rescue team to a report of a distressed dolphin in Dixie County, Florida, to the subsequent identification of the virus from brain and tissue samples obtained in a postmortem examination.

Analyses initially performed at UF's zoological medicine diagnostic laboratory ruled out the presence of other potential agents at play in the dolphin's disease, with the Bronson Animal Disease Diagnostic Laboratory in Kissimmee, Florida, verifying the presence of HPAI virus in both the lung and brain.

Those results were confirmed by the National Veterinary Services Laboratory in Ames, Iowa, which characterized the virus subtype and pathotype. The virus was confirmed to be HPAI A (H5N1) virus of HA clade 2.3.4.4b. Subsequent tissue analysis was performed at the Biosafety Level 3 enhanced laboratory at St. Jude Children's Research Hospital in Memphis.

Allison Murawski, D.V.M., a former intern with UF's aquatic animal medicine program, was first author on the study and developed a case report on the dolphin as part of her research project. She traveled to Memphis and worked closely with Richard Webby, Ph.D., who directs the World Health Organization Collaborating Center for Studies on the Ecology of Influenza in Animals and Birds at St. Jude's and served as corresponding author on the paper

Webby's laboratory investigates avian influenza cases in many species and was key in determining where the virus may have originated, what unique RNA characteristics or mutations were present that could suggest its ability to infect other mammals, and how the virus could be tracked from this source.

The researchers sequenced the genomes from local birds and looked at viruses isolated from Northeast seal populations.

"We still don't know where the dolphin got the virus and more research needs to be done," Webby said.

"This investigation was an important step in understanding this virus and is a great example where happenstance joins with curiosity, having to answer the 'why' and then seeing how the multiple groups and expertise took this to a fantastic representation of collaborative excellence," said Mike Walsh, D.V.M., an associate professor of aquatic animal health, who served as Murawski's faculty mentor.

More information: Allison Murawski et al, Highly pathogenic avian influenza A(H5N1) virus in a common bottlenose dolphin (Tursiops truncatus) in Florida, Communications Biology (2024). DOI: 10.1038/s42003-024-06173-x

Journal information: Communications Biology 

Provided by University of Florida Experts warn bird flu virus changing rapidly in largest ever outbreak

NEWS RELEASE 26-APR-2024

Florida dolphin found with highly pathogenic avian flu: Report

UNIVERSITY OF FLORIDA

The case of a Florida bottlenose dolphin found with highly pathogenic avian influenza virus, or HPAIV — a discovery made by University of Florida researchers in collaboration with multiple other agencies and one of the first reports of a constantly growing list of mammals affected by this virus — has been published in Communications Biology.

The report documents the discovery, the first finding of HPAIV in a cetacean in North America, from the initial response by UF’s Marine Animal Rescue team to a report of a distressed dolphin in Dixie County, Florida, to the subsequent identification of the virus from brain and tissue samples obtained in a postmortem examination.

Analyses initially performed at UF’s zoological medicine diagnostic laboratory ruled out the presence of other potential agents at play in the dolphin’s disease, with the Bronson Animal Disease Diagnostic Laboratory in Kissimmee, Florida, verifying the presence of HPAI virus in both the lung and brain.

Those results were confirmed by the National Veterinary Services Laboratory in Ames, Iowa, which characterized the virus subtype and pathotype. The virus was confirmed to be HPAI A (H5N1) virus of HA clade 2.3.4.4b. Subsequent tissue analysis was performed at the Biosafety Level 3 enhanced laboratory at St. Jude Children’s Research Hospital in Memphis.

Allison Murawski, D.V.M., a former intern with UF’s aquatic animal medicine program, was first author on the study and developed a case report on the dolphin as part of her research project. She traveled to Memphis and worked closely with Richard Webby, Ph.D., who directs the World Health Organization Collaborating Center for Studies on the Ecology of Influenza in Animals and Birds at St. Jude’s and served as corresponding author on the paper

Webby’s laboratory investigates avian influenza cases in many species and was key in determining where the virus may have originated, what unique RNA characteristics or mutations were present that could suggest its ability to infect other mammals, and how the virus could be tracked from this source.

The researchers sequenced the genomes from local birds and looked at viruses isolated from Northeast seal populations.

“We still don’t know where the dolphin got the virus and more research needs to be done,” Webby said.

“This investigation was an important step in understanding this virus and is a great example where happenstance joins with curiosity, having to answer the ‘why’ and then seeing how the multiple groups and expertise took this to a fantastic representation of collaborative excellence,” said Mike Walsh, D.V.M., an associate professor of aquatic animal health, who served as Murawski’s faculty mentor.

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JOURNAL

Communications Biology

DOI

10.1038/s42003-024-06173-x 

METHOD OF RESEARCH

Case study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Highly pathogenic avian influenza A(H5N1) virus in a common bottlenose dolphin (Tursiops truncatus) in Florida

ARTICLE PUBLICATION DATE

18-Apr-2024

Study suggests host response needs to be studied along with other bacteriophage research

Bacteriophage (magenta) attack Pseudomonas aeruginosa (teal) biofilms grown in 

association with respiratory epithelial cells (nuclei, yellow). Credit: Paula Zamora, 

A team of micro- and immunobiologists from the Dartmouth Geisel School of Medicine, Yale University, and the University of Pittsburgh has found evidence suggesting that future research teams planning to use bacteriophages to treat patients with multidrug-resistant bacterial infections need to also consider how cells in the host's body respond to such treatment.

In their paper published in the open-access journal PLOS Biology, the group describes experiments they conducted that involved studying the way epithelial cells in the lungs respond to bacteriophages.

Over the past decade, medical scientists have found that many of the antibiotics used to treat bacterial infections are becoming resistant, making them increasingly useless. Because of this, other scientists have been looking for new ways to treat such infections. One possible approach has involved the use of bacteriophages, which are viruses that parasitize bacteria by infecting and reproducing inside of them, leaving them unable to reproduce.

To date, most of the research involving use of bacteriophages to treat infections has taken place in Eastern Europe, where some are currently undergoing clinical trials. But such trials, the researchers involved in this new study note, do not take into consideration how cells in the body respond to such treatment. Instead, they are focused on determining which phages can be used to fight which types of bacteria, and how well they perform once employed.

The reason so little attention is paid to host cell interaction, they note, is that prior research has shown that phages can only replicate inside of the bacterial cells they invade; thus, there is little opportunity for them to elicit a response in human cells.

In this new study, the research team suggests such thinking is misguided because it fails to take into consideration the immune response in the host. To demonstrate their point, the team conducted a series of experiments involving exposing human epithelial cells from the lungs (which are the ones that become infected as part of lung diseases) to bacteriophages meant to eradicate the bacteria causing an infection.

They found that in many cases, the immune system responded by producing proinflammatory cytokines in the epithelial cells. They noted further that different phages elicited different responses, and there exists the possibility that the unique properties of some phages could be used to improve the results obtained from such therapies. They conclude by suggesting that future bacteriophage research involve inclusion of host cell response.

More information: Paula F. Zamora et al, Lytic bacteriophages induce the secretion of antiviral and proinflammatory cytokines from human respiratory epithelial cells, PLOS Biology (2024). DOI: 10.1371/journal.pbio.3002566

Journal information: PLoS Biology 

© 2024 Science X NetworkMammalian cells may consume bacteria-killing viruses to promote cellular health

Study details a common bacterial defense against viral infection

Complex of 2 proteins enhances blockage of phage replication

Peer-Reviewed Publication

OHIO STATE UNIVERSITY

COLUMBUS, Ohio – One of the many secrets to bacteria’s success is their ability to defend themselves from viruses, called phages, that infect bacteria and use their cellular machinery to make copies of themselves.

Technological advances have enabled recent identification of the proteins involved in these systems, but scientists are still digging deeper into what those proteins do.

In a new study, a team from The Ohio State University has reported on the molecular assembly of one of the most common anti-phage systems – from the family of proteins called Gabija – that is estimated to be used by at least 8.5%, and up to 18%, of all bacteria species on Earth.

Researchers found that one protein appears to have the power to fend off a phage, but when it binds to a partner protein, the resulting complex is highly adept at snipping the genome of an invading phage to render it unable to replicate.

“We think the two proteins need to form the complex to play a role in phage prevention, but we also believe one protein alone does have some anti-phage function,” said Zhangfei Shen, co-lead author of the study and a postdoctoral scholar in biological chemistry and pharmacology at Ohio State’s College of Medicine. “The full role of the second protein needs to be further studied.”

The findings add to scientific understanding of microorganisms’ evolutionary strategies and could one day be translated into biomedical applications, researchers say.

Shen and co-lead author Xiaoyuan Yang, a PhD student, work in the lab of senior author Tianmin Fu, assistant professor of biological chemistry and pharmacology at Ohio State.

The study was published April 16 in Nature Structural & Molecular Biology.

The two proteins that make up this defense system are called Gabija A and Gabija B, or GajA and GajB for short.

Researchers used cryo-electron microscopy to determine the biochemical structures of GajA and GajB individually and of what is called a supramolecular complex, GajAB, created when the two bind to form a cluster consisting of four molecules from each protein.

In experiments using Bacillus cereus bacteria as a model, researchers observed the activity of the complex in the presence of phages to gain insight into how the defense system works.

Though GajA alone showed signs of activity that could disable a phage’s DNA, the complex it formed with GajB was much more effective at ensuring phages would not be able take over the bacterial cell.

“That’s the mysterious part,” Yang said. “GajA alone is sufficient to cleave the phage nucleus, but it also does form the complex with GajB when we incubate them together. Our hypothesis is that GajA recognizes the phage’s genomic sequence, but GajB enhances that recognition and helps to cut the phage DNA.”

The large size and elongated configuration of the complex made it difficult to get the full picture of GajB’s functional contributions when bound to GajA, Shen said, leaving the team to make some assumptions about protein roles that have yet to be confirmed.

“We only know GajB helps enhance GajA activity, but we don’t yet know how it works because we only see about 50% of it on the complex,” Shen said.

One of their hypotheses is that GajB may influence the concentration level of an energy source, the nucleotide ATP (adenosine triphosphate), in the cellular environment – specifically, by driving ATP down upon detection of the phage’s presence. That would have the dual effect of expanding GajA’s phage DNA-disabling activity and stealing energy that a phage would need to start replicating, Yang said.

There is more to learn about bacterial anti-phage defense systems, but this team has already shown that blocking virus replication isn’t the only weapon in the bacterial arsenal. In a previous study, Fu, Shen, Yang and colleagues described a different defense strategy: bacteria programming their own death rather than letting phages take over a community.

This work was supported by the National Institute of General Medical Sciences.

Additional co-authors are Jiale Xie, Jacelyn Greenwald, Ila Marathe, Qingpeng Lin and Vicki Wysocki of Ohio State, and Wenjun Xie of the University of Florida.

#

Contact: Tianmin Fu, Fu.978@osu.edu

Written by Emily Caldwell, Caldwell.151@osu.edu; 614-292-8152

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JOURNAL

Nature Structural & Molecular Biology

DOI

10.1038/s41594-024-01283-w 

ARTICLE TITLE

Molecular basis of Gabija anti-phage supramolecular assemblies

ARTICLE PUBLICATION DATE

16-Apr-2024