A team from CEITEC Masaryk University (MUNI) in collaboration with researchers from two research institutes in Norway has, for the first time, captured how echovirus 18, a member of the enterovirus genus, releases its genetic material into cells to initiate infection. The study provides a structural view of an early stage of viral infection under near-native conditions. Using cryo-electron microscopy, the researchers discovered that the virus does not release its RNA through a small pore in its capsid, as had long been assumed. Instead, its protein shell partially disassembles, creating a large opening through which the viral genetic material escapes into the host cell. A detailed understanding of this genome release mechanism could eventually help develop compounds preventing enteroviruses from infecting cells.Enteroviruses are common human pathogens causing diseases ranging from the common cold and gastrointestinal infections to severe neurological disorders. Echovirus 18, the virus investigated in this study, is known primarily as a cause of meningitis and encephalitis in children. It belongs to the picornaviruses, a family of small, non-enveloped viruses whose genetic material is protected by a protein shell, the capsid, organized with icosahedral symmetry.To replicate within a cell, the enteroviruses must release their RNA – the molecule that carries viral genetic information – from the capsid, into the cell cytoplasm. Although this step is crucial for initiating infection, it has never been observed in infected cells.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/CEITEC_Vedci_z_CEITEC_jako_prvni_zachytili_jak_enteroviry_spousteji_infekci_bunek_71d553bb0e.jpg" alt="CEITEC/Plevka Lab: CEITEC Scientists Are the First to Capture How Enteroviruses Initiate Infection: View into a cell infected by echovirus 18. Echovirus 18 is shown in green and yellow, ribosomes in violet, and actin filaments in cyan. Scale 50 nm. " srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_CEITEC_Vedci_z_CEITEC_jako_prvni_zachytili_jak_enteroviry_spousteji_infekci_bunek_71d553bb0e.jpg 221w," sizes="100vw" width="1600" height="1128">“For a long time, two main theories existed about how picornaviruses deliver their RNA genomes into cells. One proposed that the genome leaves the capsid through a small opening. The other, supported by earlier work from our laboratory, suggested that the genome escapes from partially disassembled capsids missing pentamers of capsid proteins. However, both models were based on experiments with virus particles outside cells. We wanted to go one step further and see what really happens during infection inside a cell,” says <a target="_blank" rel="noopener noreferrer" href="https://www.ceitec.eu/liya-mukhamedova-ph-d/u89248?page=publication">Liya Mukhamedova</a>, the study’s first author from CEITEC MUNI.Using cryo-electron microscopy, which allows scientists to visualize biological structures at exceptionally high resolution, the researchers observed individual echovirus 18 particles directly within infected cells. They discovered that empty virus particles in infected cells lack parts of their capsids. It is through these openings that the virus releases its RNA.The study also revealed the role of the FcRn receptor, a cell-surface molecule that enteroviruses use to enter cells. The binding of the virus to the receptor triggers structural changes in the viral particle that prime it for subsequent genome release. The team showed that receptor binding causes the loss of the so-called pocket factor, a small molecule that normally helps stabilize the virus particle. The virus otherwise remains largely intact, suggesting that receptor binding is only the first step toward uncoating, while additional factors within the cell are required to complete the process and trigger genome release.“Infection is a complex process, during which enterovirus particles sense various interactions with cell components. The binding of echovirus 18 to the FcRn host-cell receptor triggers conformational changes in the virus, priming it for genome release.” – explains <a target="_blank" rel="noopener noreferrer" href="https://www.ceitec.eu/pavel-plevka-ph-d/u26854">Pavel Plevka</a>, head of the Structural Virology Research Group.The researchers did not observe the so-called activated particles that are key intermediates in the enterovirus uncoating process. This suggests that genome release in cells occurs much faster than previous experiments had suggested.By combining structural data obtained from studies of virus particles outside living cells with observations of infected cells, the study offers a picture of how enterovirus infection begins. Moving beyond simplified experiments with isolated virus particles, it brings scientists closer to understanding the earliest stages of enterovirus infection as they occur in living cells. The study, was published in the <a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1073/pnas.2601182123">PNAS journal</a>.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/CEITEC_Vedci_z_CEITEC_jako_prvni_zachytili_jak_enteroviry_spousteji_infekci_bunek_2_3601bf1df9.jpg" alt="CEITEC/Plevka Lab: CEITEC Scientists Are the First to Capture How Enteroviruses Initiate Infection: Reconstructions of E18 particles from infected cells. The particles are rainbow-colored based on the distance from the particle center. Scale 10 nm." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_CEITEC_Vedci_z_CEITEC_jako_prvni_zachytili_jak_enteroviry_spousteji_infekci_bunek_2_3601bf1df9.jpg 245w," sizes="100vw" width="1600" height="906"><blockquote><h4>Article</h4><h4><a target="_blank" rel="noopener noreferrer" href="https://www.pnas.org/doi/10.1073/pnas.2601182123">Particles of echovirus 18 open to release their genomes in vivo</a></h4>Liya Mukhamedova, David Buchta, Zuzana Trebichalská, Yevgen Levdansky, Jana Moravcová, David Potěšil, Zbyněk Zdráhal, Dominik Hřebík, Lucie Nepovímová, Torleif Tollefsrud Gjølberg, Jan Terje Andersen, Jiří Nováček, Tibor Füzik, and Pavel PlevkaProc. Natl. Acad. Sci. U.S.A., 2026, 123, e2601182123<div>&nbsp;</div><div><a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1073/pnas.2601182123">https://doi.org/10.1073/pnas.2601182123</a></div><h6>licenced under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/">CC-BY 4.0</a></h6></blockquote><h4>Abstract</h4>Enteroviruses cause a broad spectrum of human diseases, ranging from mild respiratory or gastrointestinal infections to severe neurological disorders such as aseptic meningitis and encephalitis. Enterovirus cell entry involves receptor-mediated endocytosis followed by destabilizing rearrangements of the virus capsid that enable genome release. However, the mechanism of enterovirus genome release has not been visualized in infected cells. Here, we used cryoelectron tomography and microscopy to image echovirus 18 (E18) entry into host cells and its interaction with the neonatal Fc receptor (FcRn). 30 min postinfection, endosomes and cytoplasm contained empty capsids missing one or several pentamers of capsid proteins, providing evidence that in vivo E18 releases its genome through capsid opening. In vitro, FcRn binding induced the expulsion of pocket factors from hydrophobic pockets in VP1, priming the virus for uncoating. The cryoelectron microscopy reconstruction of genome-containing particles of E18 inside infected cells did not reveal pocket factors, indicating that receptor binding triggers the same priming process during infection. We did not detect activated particles in infected cells, suggesting that these intermediates are short-lived and rapidly release their genomes in vivo. Our results identify capsid opening as the in vivo mechanism of echovirus 18 genome release, providing structural evidence for a process previously only inferred from in vitro experiments.

CEITEC Scientists Are the First to Capture How Enteroviruses Initiate Infection 

ISC 2026 - Day 2

<h4>What if you could compress 179 days of grueling laboratory workflow into just 14 hours?</h4>In this episode of ‪ChromatographyTalk‬, ‪Organomation‬ General Manager David Oliva sits down with analytical chemist Laura Penabad to discuss her groundbreaking new research in biocatalysis and high-throughput screening. Evolving engineered enzymes typically requires checking thousands of variants—a massive bottleneck when traditional Liquid Chromatography-Mass Spectrometry (LC-MS) runs take minutes per sample. Laura reveals how her team built a modular screening platform that shatters this limitation, running samples 128 times faster than standard methods without sacrificing analytical accuracy.Laura breaks down the "orchestra" of technologies making this possible, including coupling nanoliter droplet microfluidics with Cyclic Ion Mobility-Mass Spectrometry (cIM-MS) to separate complex chemical isomers in milliseconds. She also shares the chaotic but triumphant behind-the-scenes stories of her PhD journey—from presenting a "comically bad" early poster at ASMS to recruiting an undergraduate mechanical engineer to build custom automation software from scratch.If you are an early-career researcher, a mass spec enthusiast, or curious about the future of synthetic biology and machine learning in chemistry, this episode is packed with invaluable intuition and advice.<h3>Video Transcription</h3><h4>From Months to Hours: Droplet Ion Mobility–MS for Biocatalysis Screening</h4>High-throughput screening is central to directed enzyme evolution, but conventional analytical workflows can create a difficult compromise: extremely fast screens often provide limited structural information, while techniques such as LC-MS offer much richer chemical insight at the cost of throughput. In a recent interview, analytical chemist Laura described how her work with droplet-based cyclic ion mobility mass spectrometry is helping bridge that gap—providing rapid analysis while retaining the ability to distinguish structurally similar products.Her research grew from an initially modest proof of concept into a screening platform capable of analyzing a 96-well plate in roughly ten minutes. The resulting workflow was approximately 128 times faster than a conventional three-minute LC-MS analysis, opening new possibilities for directed evolution campaigns in which thousands of enzyme variants need to be evaluated.<h4>Directed evolution needs better analytical screening</h4>Biocatalysis takes advantage of enzymes as highly selective catalysts capable of performing reactions under relatively mild conditions. Directed evolution extends those capabilities by deliberately modifying enzyme sequences, expressing large numbers of variants, screening their activity, and using the best-performing mutants as starting points for subsequent rounds of evolution.The process can be repeated multiple times, progressively steering an enzyme toward improved activity, altered substrate specificity, or even chemistry that does not occur naturally.But the effectiveness of directed evolution depends heavily on the screening step. The more variants that can be analyzed—and the more useful chemical information that can be collected for each one—the more effectively researchers can explore the enormous sequence space available to an enzyme.For Laura, this created a clear analytical challenge: develop a screening platform that was substantially faster than conventional chromatographic analysis without sacrificing the structural discrimination needed for chemically similar products.<h4>From an imperfect first experiment to a working platform</h4>The project did not begin with a polished high-throughput workflow.Laura recalled looking back at her 2023 ASMS poster, where the early system was still working with standards rather than true isomeric samples. Droplet introduction was slow—around six seconds per droplet—and the signals were far from the ideal reproducible, square, flat-topped profiles expected from replicate droplets.Nevertheless, simply producing a droplet signal represented an important first milestone.The decisive change came when the project stopped being treated merely as a demonstration that droplet ion mobility–MS could work and instead became a deliberate effort to build a robust screening platform.Laura approached the problem in modules. First came reliable droplet introduction. Then the ion mobility separation method. Quantification became another independent component. Matrix effects were introduced later, gradually making the system resemble the conditions expected with real screening samples.Each layer was tested before another was added.This stepwise strategy became one of the central principles of the project: rather than attempting to optimize the entire system simultaneously, individual components were developed, challenged, and then assembled into an increasingly realistic workflow.<h4>Finding the middle ground between speed and structural information</h4>One of the biggest analytical problems in high-throughput screening is distinguishing products with the same nominal or exact mass.Constitutional isomers may contain the same atoms and therefore generate the same mass-to-charge ratio, while differing only in how functional groups are arranged within the molecular structure. Very rapid optical or mass-based screens may therefore struggle to distinguish them.Traditional LC-MS can solve many of these problems through chromatographic separation, but a several-minute analysis rapidly becomes impractical when thousands of enzyme variants must be screened.Ion mobility offered Laura’s team another option.Rather than separating compounds on a chromatographic timescale, ion mobility can differentiate ions according to their gas-phase behavior on a much shorter timescale. In the workflow described in the interview, this created a useful compromise: not the kilohertz throughput possible with some simple screening technologies, but dramatically faster structural differentiation than conventional LC-MS.The goal was therefore not simply to achieve the fastest possible screen, but to find a middle-throughput analytical regime with enough resolving power to answer chemically meaningful questions.<h4>A 96-well plate in about ten minutes</h4>That strategy eventually produced one of the most striking results of the project.The droplet cyclic ion mobility–MS platform processed a 96-well plate in roughly ten minutes, while maintaining quantitative results comparable with the conventional LC-MS workflow used for comparison. According to the interview, this represented an approximately 128-fold increase in analysis speed relative to a three-minute LC-MS run.Laura described the successful plate experiment less as a surprise than as confirmation that the modular development strategy had worked.Before reaching that point, the workflow had already been challenged through a sequence of increasingly demanding experiments: droplet formation, ion mobility separation, calibration, matrix-containing calibration, and cross-testing analytes at different concentrations. By the time the complete plate was analyzed, each individual part of the analytical system had already been tested under progressively more realistic conditions.<h4>What does that speed mean for directed evolution?</h4>The impact becomes even clearer when the workflow is considered at the scale of an entire directed-evolution campaign.Laura’s manuscript estimated that a five-round campaign involving 5,000 variants would require approximately 179 days using the conventional LC-MS workflow but only about 14 hours using the new platform.Compressing months of analytical work into less than a day has consequences beyond laboratory productivity.It allows researchers to screen more enzyme variants and therefore sample a larger portion of sequence space. But the resulting datasets may also become increasingly valuable for computational approaches.Rather than retaining information only about the best-performing enzyme variant, researchers can preserve data describing variants that performed poorly as well as those that succeeded. When genotype and phenotype information remain linked through the well-plate workflow, these larger datasets can potentially provide richer input for machine-learning models designed to guide subsequent rounds of enzyme evolution.Faster analysis therefore does more than accelerate an existing experiment—it can change the scale and design of the experiment itself.<h4>Balancing ion mobility resolution and signal</h4>Increasing cyclic ion mobility separation time can improve resolution, but it also introduces an important trade-off: additional passes can reduce signal.Laura optimized this balance experimentally by continuously infusing mixtures containing both isomers and progressively adjusting the ion mobility conditions. After tuning parameters such as wave height and velocity, increasing the separation to three passes provided baseline resolution at the high analyte concentrations used during method development.<blockquote>Concentration, however, also mattered.</blockquote>At higher ion populations, space-charge effects could broaden peaks and reduce the baseline separation. This meant that the optimal number of passes could not be selected independently of the concentration range required by the final assay.Her broader advice for optimization is therefore application-driven: decide first what the analytical method actually needs to accomplish.More speed will almost always require sacrificing something—resolution, signal intensity, quantitative precision, or another performance parameter. The key is to identify which compromise the application can tolerate and then optimize the system around that requirement.<h4>Solving droplet carryover with a practical compromise</h4>Droplet-based workflows present their own engineering challenges, including carryover between neighboring samples.In Laura’s system, analytes showed little tendency to partition into the fluorinated oil separating aqueous droplets within the Teflon tubing. The more troublesome carryover occurred closer to electrospray ionization, where a small amount of sample could remain associated with the interface and appear when the next droplet arrived.Rather than adding excessive engineering complexity to an already elaborate platform, the researchers adopted a pragmatic solution: a sacrificial wash droplet between analytical samples.It is an example of a recurring theme throughout the project. The objective was not to construct the theoretically most sophisticated droplet system, but to create a screening workflow that remained sufficiently robust, reproducible, and practical for large numbers of samples.<h4>High-throughput analysis also requires high-throughput data processing</h4>Accelerating the mass spectrometry experiment created another bottleneck: the data.The instrument produced a continuous intensity-versus-time trace rather than a neatly organized well-plate dataset. With small experiments, Laura could manually identify individual droplets and process the results in spreadsheets. That approach quickly became unrealistic as sample numbers increased.The solution emerged through collaboration with an undergraduate mentee, Aiden, who helped develop a dedicated software tool for processing the continuous traces.Laura defined how the software should behave and how the analytical information should be organized, while Aiden developed the computational implementation. The workflow itself was subsequently adjusted to make automated data processing more reliable—for example, by introducing marker columns that allowed the software to recognize the end of each plate row.The resulting tool can accept the acquired traces together with information about plate dimensions and replicates and automatically return parameters including peak identity, duration, and the corresponding well position. A later version also generated an automatically populated heat map.The experience illustrates how improving analytical throughput often requires simultaneous development of instrumentation, experimental design, and informatics. Making the measurement faster is useful only if the resulting data can be processed at a comparable speed.<h4>Mentoring became part of the scientific process</h4>The software project also reflects another theme Laura emphasized throughout the interview: the value of mentoring.Several younger researchers contributed directly to the development of the final platform. Laura described mentees not simply as additional hands in the laboratory but as scientists capable of proposing their own hypotheses and experimental ideas.Working with undergraduate researchers also influenced the way she organized experiments.Because their available laboratory time was limited, each task needed to have a clear purpose. That encouraged a more disciplined approach to experimental planning: instead of performing experiments simply because they could be done, the team had to ask which experiment would most efficiently answer the next important question.In that sense, mentoring became another mechanism for improving the research itself.<h4>The next step: continuous, automated screening</h4>Despite the dramatic increase in analytical speed, the current workflow still includes manual operations such as loading tubing and connecting the sample stream to the mass spectrometer.The next engineering challenge is therefore automation.Laura described ongoing work using the Venturi effect to pull samples directly from wells into the droplet system. Building on previous work in the laboratory with 96-well plates, she has already tested this approach with as many as 2,000 samples.The long-term direction is clear: continuous and robust droplet generation, automated handling of thousands of samples, rapid ion mobility separation, mass spectrometric detection, and automated reconstruction of the resulting data into plate-based outputs.Combining those elements could move the system closer to the type of large-scale screening required for increasingly ambitious biocatalysis campaigns.<h4>Learning mass spectrometry one problem at a time</h4>Laura also reflected on the broader experience of developing the platform during her PhD.Ion mobility and mass spectrometry initially appeared intimidating, particularly because they combine concepts from analytical chemistry, physical chemistry, separations, instrumentation, and electrical engineering. What eventually changed was not simply learning more facts, but developing the ability to move repeatedly between theory and experiment.An unexpected result sends the researcher back to the underlying theory. A better understanding suggests a modified experiment. That experiment creates another observation, gradually building intuition about how the system behaves.Her advice to early-career scientists is therefore to accept that this process takes time.Advanced analytical techniques may initially appear overwhelming, but understanding develops incrementally through repeated interaction between theory, experimentation, failure, and refinement. Equally important, she emphasized the role of the supportive ion mobility–mass spectrometry community in making a technically demanding field more approachable for young researchers.From the first inconsistent droplets to a platform capable of processing thousands of samples, that iterative mindset ultimately shaped the entire project.<blockquote>This text has been automatically transcribed from a video presentation using AI technology. It may contain inaccuracies and is not guaranteed to be 100% correct.</blockquote><blockquote><h4>Concentrating on Chromatography Podcast</h4>Dive into the frontiers of chromatography, mass spectrometry, and sample preparation with host David Oliva. Each episode features candid conversations with leading researchers, industry innovators, and passionate scientists who are shaping the future of analytical chemistry. From decoding PFAS detection challenges to exploring the latest in AI-assisted liquid chromatography, this show uncovers practical workflows, sustainability breakthroughs, and the real-world impact of separation science. Whether you’re a chromatographer, lab professional, or researcher you'll discover inspiring content!You can find Concentrating on Chromatography Podcast in podcast apps:<ul><li><a target="_blank" rel="noopener noreferrer" href="https://open.spotify.com/show/1wZg67rCjoGju4yhqxI3tL">Spotify</a></li><li><a target="_blank" rel="noopener noreferrer" href="https://podcasts.apple.com/tz/podcast/concentrating-on-chromatography/id1788429185">Apple podcast</a></li><li><a target="_blank" rel="noopener noreferrer" href="https://podscan.fm/podcasts/concentrating-on-chromatography">podscan</a></li></ul>and on <a target="_blank" rel="noopener noreferrer" href="https://www.youtube.com/@ChromatographyTalk/videos">YouTube channel</a></blockquote>

Droplet Cyclic Ion Mobility Mass Spec: Compressing Months of Enzyme Screening Into Just 14 Hours

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Droplet Cyclic Ion Mobility Mass Spec: Compressing Months of Enzyme Screening Into Just 14 Hours

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