Ancient viruses serving as gene delivery couriers to help bacteria resist antibiotics

John Innes Centre

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Left: fluorescence microscopy showing C. crescentus bacterial cells producing GTA particles (cells have been engineered to glow green when producing GTAs). Right: cryo-electron microscopy tomogram showing a ‘cross-section’ through a single C. crescentus cell producing GTA particles (magenta and yellow). Bacterial envelope layers are shown in blue, cyan, and green. A nutrient storage granule is visible (grey). Ribosomes (protein factories) are shown in orange.

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Credit: Dr Emma Banks

Research has shed important new light on the enemies-turned-allies that allow bacteria to exchange genes, including those linked to antimicrobial resistance (AMR).   

 

The insights, which expand our understanding of the major global health threat of AMR, came as John Innes Centre researchers investigated the curious phenomena of gene transfer agents (GTAs).   

These gene-carrying particles look like bacteriophages (viruses that infect bacteria), but they have been domesticated from ancient viruses and put to beneficial use under the control of the bacterial host cell.  

Acting as couriers, they take up parcels of host bacterial DNA and deliver them to neighbouring bacteria. This “selfless” sharing, known as horizontal gene transfer, can rapidly spread useful traits including genes that confer resistance to antibiotic drugs used to treat infections. 

A crucial GTA life stage is host cell lysis: the breaking down of a host cell to release DNA-packed GTA particles. Previously, it was unclear how GTA particles escape their host bacterial cells. 

In this study, which appears in Nature Microbiology, the team used a deep sequencing-based screening method to identify genes critical for GTA function in the model bacterium Caulobacter crescentus.  

This identified a three-gene control hub, LypABC, encoding bacterial proteins. When these lypABC genes were deleted, bacteria could no longer lyse to release GTA particles. In contrast, by overexpressing the lypABC hub they obtained a very high proportion of lysing cells. Together, these experiments identified LypABC as a control mechanism for GTA-mediated cell lysis.  

Surprisingly, LypABC resembles a bacterial anti-phage immune system since it contains protein domains which are typically required for defence against viruses. However, this collaborative effort between the John Innes Centre, the University of York, and the Rowland Institute at Harvard, suggests it has been repurposed to release GTA particles for gene transfer.  

They also identified a regulatory protein which is required for strict control of both GTA activation and GTA-mediated lysis. This control is important as misregulation of LypABC is highly toxic to bacterial cells.  

In highlighting the plasticity of bacterial domains, the study advances fundamental knowledge of how gene transfer occurs between bacterial cells and offers an important clue to understanding how AMR occurs.  

First author of the study Dr Emma Banks, a Royal Commission for the Exhibition of 1851 Research Fellow, said: “What’s particularly interesting is that LypABC looks like an immune system, yet bacteria are using it to release GTA particles. It suggests that immune systems can be repurposed to help bacteria share DNA with each other - a process that can contribute to the spread of antibiotic resistance.” 

The next step for the research is to discover how the LypABC control hub is activated and how it functions to control the rupture of bacterial cells and release of GTA particles. 

“A bacterial CARD-NLR-like immune system controls the release of gene transfer agents”, appears in Nature Microbiology.  

 

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Journal

Nature Microbiology

DOI

10.1038/s41564-026-02316-4 

Method of Research

Experimental study

Subject of Research

Cells

Article Title

A bacterial CARD–NLR-like immune system controls the release of gene transfer agents

Article Publication Date

16-Apr-2026

 

How gut bacteria and acute stress are linked

Possible avenue for new strategies related to acute stress responses and stress-related conditions

University of Vienna

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The gut microbiome influences numerous physiological processes. Researchers at the University of Vienna have now demonstrated for the first time that, in healthy adults, the diversity of gut bacteria and their capacity to produce certain metabolites are associated with the acute stress response - particularly stress reactivity. Higher microbial diversity was associated with stronger hormonal and subjectively perceived stress reactivity. The results suggest that the gut microbiome may play a role in regulating the acute stress response. The study was published in Neurobiology of Stress.

The gut microbiome comprises all microorganisms living in the gut, which, among other things, perform important functions in metabolism and the immune system and are also connected to the brain through various pathways. Research suggests they can modulate the stress response. However, it has remained unclear until now whether differences in the human gut microbiome are actually associated with acute stress reactivity.

The latest findings by researchers Thomas Karner, Isabella Wagner, David Berry, and Paul Forbes from the Faculty of Psychology and the Center for Microbiology and Environmental Systems Sciences (CeMESS) at the University of Vienna provide new evidence that the gut microbiome, and thus potentially also diet and lifestyle, is associated with how our bodies respond to stress. In the long term, targeted modulation of gut microbial composition and its metabolites, particularly short-chain fatty acids, could represent a possible avenue for new strategies to related to acute stress responses, stress-related conditions and improve well-being.

Stress tests, saliva samples, and more provide insight into the association

In the study, healthy participants either underwent a standardized stress test or performed a comparable, stress-free task. Stress hormones (cortisol) in saliva and subjective stress levels were measured. In addition, the gut microbiome was analyzed using stool samples. Both the composition of the microbiome and the estimated production capacity of short-chain fatty acids were examined. The results show that higher microbial diversity was associated with higher hormonal and subjective stress reactivity. Greater microbial diversity is often associated with a more stable and resilient microbial ecosystem and with greater functional flexibility, which may contribute to the appropriate regulation of stress responses.

"A stronger acute stress response is not necessarily detrimental. Appropriate activation of the stress system enables flexible adaptation to challenges and threats. A greater diversity of gut bacteria, as well as certain metabolic products, could play a supportive role in this process," explains study leader and psychologist Thomas Karner.

Complex relationship between microbial metabolites and stress reactivity

Furthermore, stress reactivity was associated with gut bacteria’s capacity to produce different metabolic products: a higher estimated capacity for butyrate production was associated with higher stress reactivity, whereas higher propionate production was associated with lower reactivity. Butyrate and propionate are short-chain fatty acids produced by gut bacteria that are involved in metabolic and immune processes and can also affect the brain. This suggests that the relationship between microbial metabolites and the acute stress response is more complex and cannot be reduced to a single direction.

The results provide new insights into possible biological mechanisms of stress regulation and underscore the role of the gut microbiome and its metabolites as potential factors influencing the stress system and the acute stress response in humans.

Summary:

• Higher gut microbial diversity is associated with higher hormonal and subjective stress reactivity in healthy adults
• Estimated capacity for short-chain fatty acid production is associated with hormonal stress reactivity. Higher butyrate production is associated with higher stress reactivity, while higher propionate production is associated with lower stress reactivity
• The findings demonstrate an association between the gut microbiome and acute stress, as well as the possible role of the gut microbiome as a factor influencing the stress system
• In the long term, changes in the gut microbiome and its metabolites, for example, through diet or targeted interventions, could represent a possible approach to influencing stress responses and stress-related conditions

About the University of Vienna: 

At the University of Vienna, curiosity has been the core principle of academic life for more than 650 years. For over 650 years the University of Vienna has stood for education, research and innovation. Today, it is ranked among the top 100 and thus the top four per cent of all universities worldwide and is globally connected. With degree programmes covering over 180 disciplines, and more than 10,000 employees we are one of the largest academic institutions in Europe. Here, people from a broad spectrum of disciplines come together to carry out research at the highest level and develop solutions for current and future challenges. Its students and graduates develop reflected and sustainable solutions to complex challenges using innovative spirit and curiosity.

You can find out more about stress here in the special feature Don't stress! in the University of Vienna’s science magazine Rudolphina.

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Journal

Neurobiology of Stress

DOI

10.1016/j.ynstr.2026.100807 

Article Title

Gut microbial diversity and inferred capacity to produce short-chain fatty acids are associated with acute stress reactivity in healthy adults

Article Publication Date

13-Apr-2026

 

Closing the carbon cycle: Unraveling the roles of light and heat in CO2 photocatalysis

Researchers reveal how photocatalytic and photothermal processes work together to enhance CO2-to-CH4 conversion

Chiba University

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Photocatalytic reduction test of CO2 using Ru–Ni–ZrO2 catalyst when the reactor was cooled with liquid (left) and when the reactor was not cooled (right).

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Credit: Professor Yasuo Izumi from Chiba University, Japan

Rising carbon dioxide (CO2) emissions from human activities are the largest contributor to global warming. According to the International Energy Agency (IEA), global CO₂ emissions reached an all-time high of 37.8 gigatons in 2024. While some of this CO2 is absorbed by soil, forests, and the oceans, a large fraction remains in the atmosphere, where it can persist for hundreds to thousands of years, leading to long-term impacts on the global climate.

To address this challenge, scientists are exploring ways to convert CO2 into useful fuels, creating a closed carbon cycle. One promising approach is photocatalytic reduction, in which CO2 is converted into methane using a catalyst powered by sunlight. However, the efficiency of this process is still too low for practical use. A key difficulty lies in understanding how the reaction occurs—whether it is driven by true photocatalytic processes involving light-induced electron excitation, or by heat generated from light, known as the photothermal effect.

Now, a team led by Professor Yasuo Izumi at the Graduate School of Science at Chiba University, Japan, has elucidated these pathways. Their study, available online on March 20, 2026, and published in Volume 148, Issue 13 of the Journal of the American Chemical Society on April 8, 2026, achieved one of the highest reported rates of CO2-to-methane conversion to date, reaching up to 10 millimoles per gram of catalyst per hour. By clarifying the underlying reaction mechanisms, their work provides important insights that could guide the design of more efficient catalysts for CO2 conversion.

The team included first author Masahito Sasaki, along with Tomoki Oyumi and Dr. Keisuke Hara from the Graduate School of Science and Engineering, Chiba University, and Associate Professor Hongwei Zhang from the Biogas Institute of the Ministry of Agriculture and Rural Affairs, China (and a former Ph.D. student at Chiba University).

Prof. Izumi explains the current challenge: “The true reaction pathway and the catalytic role responsible for it remain uncertain in photocatalysis, where charge separation, hot spots, and energetic modulation of ground and excited states are involved.”

To separate photothermal and photocatalytic effects in CO2 reduction, the researchers irradiated Ru–Ni–ZrO2 and Ni–ZrO2 catalysts with ultraviolet (UV)–visible light at varying intensities from 90 to 900 milliwatts per centimeter square (mW cm−2) while carefully controlling the temperature of the system, either maintaining it at 295 K (22 °C) using a cooling bath or allowing it to increase under irradiation.

Without the cooling bath, the Ru–Ni–ZrO2 catalyst converted CO2 to methane more than 2.7 times faster than the Ni–ZrO2 catalyst, reaching over 7.9 millimoles per gram of catalyst per hour. Under these conditions, the photothermal effects became increasingly dominant. CO2 is directly adsorbed onto Ru–Ni active sites, where it is more easily activated and dissociated into CO and oxygen atom with a low activation energy of 0.45 eV—much lower than the 0.79 eV required on pure nickel.

In contrast, when the cooling bath was applied, the reaction was primarily driven by photocatalytic processes, with some contribution from local heating. Light generates separated electrical charges on the ZrO2 surface, forming intermediate species via OCOH intermediates at oxygen vacancy sites. These intermediates are then transferred to nickel sites, where they undergo multiple hydrogenation steps to form methane. Under these conditions, localized ‘hotspots’ can form on nickel, where temperatures can reach 126 °C under strong irradiation (654 mW cm−2). At these sites, the methane formation rate is 1.72 times higher than expected from simple thermal reactions, showing that both charge separation and local heating work together.

Together, these findings show that CO2 reduction depends on a balance between photocatalytic and photothermal processes, with their relative contributions determined by temperature and light intensity. By clearly identifying how these mechanisms interact, the study provides a deeper understanding of light-driven CO2 conversion and offers a pathway toward designing more efficient catalysts.

The researchers aim to further expand this approach to produce more complex and valuable chemicals. “Going forward, we aim to further enhance the efficiency of sustainable CO2 utilization technologies using sunlight, such as the synthesis of C2 and C3 compounds and alcohols,” says Prof. Izumi.

To see more news from Chiba University, click here.

 

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Reference:
DOI: 10.1021/jacs.5c17533

Authors: Masahito Sasaki1, Tomoki Oyumi1, Keisuke Hara1, Hongwei Zhang2, and Yasuo Izumi1

Affiliations: 1Department of Chemistry, Graduate School of Science, Chiba University, Japan

2Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture and Rural Affairs, the People’s Republic of China

 

About Professor Yasuo Izumi from Chiba University, Japan
Professor Yasuo Izumi is a faculty member at the Graduate School of Science, Chiba University, Japan, studying catalytic processes on solid surfaces. His research focuses on complex reaction pathways using advanced analytical techniques to design efficient catalysts for a sustainable society. He earned his Doctor of Science from the University of Tokyo (1993), with work on supported metal cluster catalysts. Prof. Izumi’s recent research explores the photocatalytic conversion of CO₂ into fuels and valuable resources. He is a member of several scientific societies, including the Chemical Society of Japan and the American Chemical Society, and has authored over 100 publications.

 

Funding:
The study received financial support for Scientific Research B (grant numbers: 24K01522 and 20H02834) from the Japan Society for the Promotion of Science. X-ray absorption experiments were performed with the approval of the Photon Factory Proposal Review Committee (grant numbers: 2022G527, 2021G546, 2020G676, and 2019G141).

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Journal

Journal of the American Chemical Society

DOI

10.1021/jacs.5c17533 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Charge Separation and/or Hot Spots: Clarification of Efficient CO2 Reduction over Ru–Ni Nanoparticles Compared to Photocatalysis on Ru–Ni–ZrO2 Composites

Article Publication Date

18-Apr-2026

 

Why the Nordic hamstring exercise protects against injury

Training helps hamstring muscles produce force at longer lengths without overstretching muscle fibers

Journal of Sport and Health Science

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image: 

Adaptations in the hamstring muscle-tendon unit following a 9-week eccentric training program. The results demonstrate that while training allows muscle fibers to operate over significantly longer active lengths (top right), the estimated active sarcomere lengths remain near their optimal range for force production (bottom right). This suggests that the muscle adapts to the high demands of the Nordic hamstring exercise by increasing serial sarcomere number, effectively allowing the muscle to reach greater lengths without overstretching its individual functional units.

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Credit: Dr. Max Andrews from The University of Queensland Image Source Link: https://doi.org/10.1016/j.jshs.2026.101134

Hamstring injuries are among the most common injuries in sports, particularly in activities involving sprinting and rapid acceleration. They account for roughly 10% of injuries in field-based sports and often result in significant time away from competition. Despite their frequency, the mechanisms underlying the effectiveness of certain training programs in preventing these injuries remain poorly understood.

Researchers from The University of Queensland and the University of Southern Queensland, in collaboration with Stanford University, investigated how nine weeks of Nordic hamstring exercise training affects the hamstring muscle function. Published in the Journal of Sport and Health Science on March 19, 2026, the study examined how this widely used injury-prevention exercise alters the mechanics of the biceps femoris long head—the hamstring muscle most commonly injured during sprinting.

“Previous research has shown that exercises such as the Nordic hamstring exercise are very effective at reducing hamstring injury risk,” said first author Dr. Max Andrews, who conducted the study as a visiting researcher at Stanford and is now a postdoctoral fellow at The University of Queensland. “These exercises target the lengthening phase of muscle contraction and are known to increase eccentric strength and muscle fascicle length. However, we still don’t fully understand how these structural adaptations alter the muscle mechanics during exercise to produce this protective effect, which is what motivated this study.”

To investigate these changes, the researchers had participants complete nine weeks of supervised Nordic hamstring exercise training. During the training, researchers measured hamstring strength and used ultrasound imaging to track the behavior of muscle fibers, while motion capture was used to estimate changes in the length of the entire muscle–tendon unit. The researchers also estimated sarcomere lengths—the microscopic contractile units responsible for producing muscle force—by combining fascicle length measurements obtained during the exercise with previously measured serial sarcomere numbers.

After nine weeks of training, eccentric knee flexor strength increased by about 40%, allowing participants to control the Nordic hamstring exercise through a greater range of motion. During the exercise, after training participants could lean further before reaching peak force. As a result, the hamstring muscle–tendon unit reached longer lengths during the movement, while the muscle fibers themselves reached lengths about 25% greater than before training. Despite these longer fiber lengths, the estimated lengths of the sarcomeres did not change.

According to the researchers, this finding is consistent with the addition of sarcomeres in series within the muscle fibers—an adaptation for which previous work from the same group has provided evidence. By adding sarcomeres end-to-end, muscle fibers become longer while each individual sarcomere continues to operate near its optimal length during contraction. This structural adaptation allows the muscle to generate force effectively even when stretched to longer lengths, such as during sprinting.

“Following training, the muscle fibers can stretch to longer lengths during the exercise without overstretching the sarcomeres,” said senior author Dr. Patricio Pincheira, from the University of Southern Queensland. “This may be one reason why eccentric training is effective at reducing hamstring injury risk. By increasing fiber length through serial sarcomere addition, the hamstrings can generate high forces across a wider range of muscle lengths, which may allow them to stretch further without overstretching.”

Previous findings show that hamstring strains often occur during the late swing phase of sprinting, when the muscles lengthen rapidly while producing high forces. If muscle fibers can tolerate longer lengths without overstretching the sarcomeres, they may be better able to withstand these demands.

“One of the long-standing questions has been why the Nordic hamstring exercise is effective at reducing injury risk,” said Dr. Pincheira. “Our findings suggest that the muscle adapts in a way that allows it to generate force at longer lengths, which may help the hamstrings tolerate the large mechanical demands placed on them during dynamic movements.”

The findings help bridge the gap between laboratory measurements of muscle structure and the real-world effectiveness of hamstring injury-prevention programs. A better understanding of muscle adaptation to eccentric training could help refine exercise prescription in practice. This insight could ultimately enable coaches and clinicians to develop more targeted and effective strategies to reduce one of the most persistent injuries in sport.

 

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Reference
DOI: 10.1016/j.jshs.2026.101134

About The University of Queensland
The University of Queensland (UQ) is a leading public research university in Brisbane, Australia, founded in 1909. A member of the prestigious Group of Eight, it is globally recognized for excellence in teaching, research, and innovation. UQ offers diverse programs across science, engineering, medicine, business, and the humanities. Its strong research output includes contributions to major medical and technological advancements. With a vibrant international student community and world-class campuses, UQ plays a key role in shaping global knowledge and future leaders.
Website: https://www.uq.edu.au/

About Dr. Max H. Andrews from The University of Queensland
Dr. Max H. Andrews is a Postdoctoral Research Fellow in the School of Human Movement and Nutrition Sciences at The University of Queensland (UQ), Brisbane, Australia. His research focuses on muscle physiology, particularly how eccentric training influences muscle structure and helps prevent hamstring injuries. He completed his PhD at UQ, where he developed expertise in advanced imaging and neuromuscular assessment techniques. Dr Andrews’ work aims to bridge laboratory findings with real-world sports performance, contributing to improved injury prevention strategies and athlete care.

Funding information
This work was supported by the Australian Research Council Discovery Project (DP200101476), Stanford Graduate Fellowship, The University of Queensland Graduate Scholarship, National Health and Medical Research Council of Australia Fellowship (#1194937), and Wu Tsai Human Performance Alliance at Stanford University and the Joe and Clara Tsai Foundation.

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Journal

Journal of Sport and Health Science

DOI

10.1016/j.jshs.2026.101134 

Method of Research

Experimental study

Subject of Research

People

Article Title

Adaptations in biceps femoris long-head muscle-tendon mechanics during the Nordic hamstring exercise in response to 9 weeks of training

 

Saving water, generating energy and making tomato cultivation more sustainable at the same time

The method involves planting tomatoes beneath solar panels, taking advantage of the benefits to the plant provided by the shade cast by the photovoltaic installation

University of Seville

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Sustainable production of horticultural crops based on agrivoltaic systems

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Credit: University of Seville

Researchers from the University of Seville (US) and the Polytechnic University of Madrid (UPM) have demonstrated that it is possible to grow tomatoes and generate solar energy simultaneously, a key strategy for tackling global water scarcity. The study, carried out in Madrid and Seville during the spring of 2024, evaluated the use of agrovoltaic systems and regulated deficit irrigation to optimise water resources in tomato cultivation. The results show that, although using less water reduces the volume of the harvest, the overall outcome is a more efficient and sustainable process. 

This innovative combination aims to reduce the plants’ evaporative demand through the shade provided by photovoltaic panels, enabling a more efficient use of land and water. The research compared three irrigation methods: a control group with full irrigation, a regulated deficit irrigation (RDI) system based on the plant’s water status, and an agrovoltaic (AG) system that applied the same water restriction under solar panels. The study measured variables such as leaf water potential and gas exchange to monitor plant stress at different growth stages. The results indicate that, although the shade from the panels reduces available radiation, the design of the system permits adequate plant development to be maintained at most stages of the crop cycle.

One of the most notable findings is that the deficit irrigation strategy reduced water consumption by approximately 50% compared to traditional irrigation. However, this drastic reduction in water led to a yield decrease of around 20% in the RDI treatment, attributed mainly to severe water stress conditions during the ripening phase. Despite this drop in total tomato production, irrigation water productivity increased significantly in the Seville treatments, demonstrating that more fruit can be obtained for every drop of water invested.

Furthermore, the overall success of the agrovoltaic system was validated by the Land Equivalent Ratio (LER), which combines the efficiency of agricultural and electricity production. The values obtained—1.54 in Madrid and 1.67 in Seville—confirm that combined production is far more efficient than growing tomatoes and generating energy on separate plots. This implies that, although tomato yield decreases under the panels, the system’s profitability and sustainability increase thanks to the generation of clean energy in the same space.

In conclusion, the study highlights that agrovoltaics is a promising tool for the agriculture of the future, although it requires more precise irrigation management to avoid excessive stress. The researchers suggest that combining plant measurements with soil moisture sensors could further optimise these systems. This advance points to the sustainable dual use of land, offering a viable solution to the challenges of climate change and the energy transition.

The study forms part of the Ministry of Science and Innovation and the State Research Agency’s PID2021-122772OB-I00 project, entitled ‘Sustainable vegetable production based on agrovoltaic systems’. It was led by experts from the ETSIAAB at the Polytechnic University of Madrid, CEIGRAM and the ETSIA at the University of Seville. The results are published in the prestigious scientific journal Agricultural Water Management.

 

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Journal

Agricultural Water Management

DOI

10.1016/j.agwat.2026.110281 

Article Title

Regulated deficit irrigation based on plant water status and Agrivoltaic systems as possible improvements on water resources management in tomato