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Phage Chemical “Crosstalk” Can Backfire, Steering Responders Into Lysogeny
Phages have been known to trade chemical messages to guide their life‑cycle decisions, but new research shows that some of those messages function more like Trojan horses than helpful signals. By releasing peptides (arbitrium) cues, one phage can mislead another into choosing dormancy at a moment when lysis would normally be favored—a strategic manipulation that shifts the competitive balance between viruses sharing the same bacterial host.
Bacteriophages rely on a simple but consequential choice each time they enter a host cell: burst the cell open to release new viral particles (lysis) or integrate into the genome and lie low (lysogeny). In recent years, researchers have uncovered that some phages don’t make this decision alone. Instead, they use short peptides—part of a communication system known as arbitrium—to optimize their lysis/lysogeny switch. High peptide levels signal that hosts are running out, nudging the phage toward dormancy; low levels encourage lytic growth.
A new study from the University of Exeter titled “Arbitrium phages can manipulate each other’s lysis/lysogeny decisions,” and published in Cell, shows that this viral messaging system isn’t as private as once thought. The team found that arbitrium signals can cross species boundaries, allowing one phage to influence the developmental decisions of another. And in some cases, that influence amounts to a molecular trick: a signal that pushes the receiving phage toward lysogeny even when conditions would normally favor lysis.
The researchers describe this as a form of phage crosstalk—and in certain contexts, a manipulative one. By secreting peptides that resemble the arbitrium signals of other phages, a virus can effectively convince its competitor to stand down. The responding phage enters lysogeny prematurely, sparing the bacterial host and reducing competition for the signaling phage’s own progeny.
“The decision to kill or lie dormant depends on the specific situation,” said Rebecca Woodhams, a PhD student at Exeter’s Centre for Ecology and Conservation. “When many bacteria are available, a phage should choose lysis and look to infect these potential hosts. When many hosts have already been killed, and few remain, lying low and waiting for better times is safer.”
The team demonstrated that non‑cognate peptides—signals produced by unrelated phages—can shift the lysis‑lysogeny balance toward early dormancy. This benefits the phage emitting the signal, which avoids competition, but imposes a fitness cost on the responder, which forgoes opportunities for replication.
Robyn Manley, PhD, a co-author on the study, noted that this dynamic complicates the idea of viral communication as cooperative: “Viral communication is not just cooperation. Sometimes, it is manipulation.”
“Antagonistic co-evolution between signal-emitting and signal-receiving phages to manipulate each other’s infection behaviors may explain the rapid diversification of arbitrium systems and their frequent horizontal exchange to escape the noise of crosstalk,” wrote the authors.
The work was carried out using soil‑associated phages and bacteria, but the implications extend far beyond a single ecological niche. Phage–phage interference like this could ripple through microbial communities, reshaping which bacteria survive and how viral populations compete in shared environments. Understanding how viruses interpret—and misinterpret—chemical cues could help researchers better predict infection outcomes or design phages that resist unwanted crosstalk.
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You know when you are at the eye doctor getting an updated prescription, and suddenly the world snaps into sharper focus? Physicists at the University of California (UC), Berkeley, have now done something similar for electron microscopy. By introducing phase contrast into a cryo‑electron microscope, they have delivered dramatically sharper images of some of biology’s smallest and most elusive proteins.
The advance comes from a new laser phase plate (LPP), described in the paper “Laser phase plate improves structure determination of small proteins by cryo‑EM,” which was published recently in Science. Led by physicist Holger Mueller, PhD, of UC Berkeley and Lawrence Berkeley National Laboratory, the team demonstrated that a laser‑driven phase plate can overcome one of cryo‑EM’s most persistent limitations: poor contrast for small proteins.
Cryo‑EM has transformed structural biology over the past decade, earning a Nobel Prize in 2017 for enabling high‑resolution structures without crystallization. But despite its impact, the technique still struggles with proteins below ~70 kilodaltons—a size range that includes about 90% of the human proteome. “Because of signal-to-noise limitations, the majority of human and animal proteins are too small to be analyzed by these methods [cryo-EM and cryoelectron tomography]. The increase in signal-to-noise ratio provided by this laser phase plate is expected to overcome these important limitations.”
The new LPP begins to address that problem. The LPP uses an intense, continuous‑wave laser to shift the phase of the electron beam itself. This produces true phase contrast without dimming or destabilizing the beam. Mueller described the laser focus as “75 kilowatts focused to a few microns… That’s more powerful than what you use for welding. It has more power than a military laser. It builds up the brightest continuous laser focus ever.”
Installed in a custom Thermo Fisher Titan Krios, the LPP immediately improved the clarity and resolvability of small proteins, including hemoglobin, which sits at the lower limit of what today’s cryo‑EM instruments can handle. As the authors wrote in the abstract: “Here, we show that the laser phase plate (LPP)… enhances the resolution in single-particle reconstruction of small proteins by improving specimen-motion correction, recovery of information from the early frames, as well as particle visualization, 3D classification, and alignment.”
These improvements were achieved using standard defocus ranges and reconstruction workflows. “For the most challenging cases—small particles, bad specimens—the laser produces a very considerable advantage,” Mueller said.
The impact extends beyond single‑particle analysis. Cryo‑electron tomography (cryo‑ET), which assembles multiple angular views of a molecule or protein into a three-dimensional image, stands to benefit even more. “With cryo-ET, we’re looking at small, very complicated cellular material that’s incredibly crowded inside the cell,” said Bridget Carragher, PhD, founding technical director of imaging at Biohub. “It’s like a forest of trees, and you’re trying to find one leaf on one tree in there. Cryo-ET needs a dramatic step forward in contrast, so we can start to see what’s going on inside the cell. That’s what the laser phase plate promises to give us.”
Biohub is developing a dual‑laser version of the system, designed to reduce component wear and minimize aberrations. Meanwhile, Mueller’s team is pushing toward imaging proteins as small as 17 kilodaltons, a threshold that would open access to vast regions of the human proteome previously invisible to cryo‑EM.
“This technology is a step function change for biology,” said Stephani Otte, PhD, Biohub’s vice president of imaging science. “What was once invisible will become visible—and that changes everything about how we understand disease.”
“The bottom line is, if you have a large protein and a really good sample—a fresh one or one frozen without bubbles, for example—you may not need the phase plate to get a single, high-quality image. But for a small protein and a bad sample, laser-on is best,” Mueller said. “This could fill an enormous gap in our knowledge of protein structures that can’t be crystallized or are too small for today’s cryo-EM. And it will be revolutionary for cryo-ET.”
The post Laser‑Driven Phase Contrast Enhances Cryo‑EM Resolution of Small Proteins appeared first on GEN – Genetic Engineering and Biotechnology News.
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STAT+: Updated: Tracking RFK Jr.’s promises to remake health in America
Updated June 11, 2026
WASHINGTON — A pledge to “Make America Healthy Again” earned Robert F. Kennedy Jr. his job atop U.S. health agencies a year and some change ago. He’s now had the opportunity to turn his words into action, with mixed results.
“All one needs” to prove the health secretary’s attentiveness is to “review my unprecedented list of accomplishments on a wide range of issues, all of which I drove,” Kennedy posted on X on Wednesday in response to a journalist.
Updated June 11, 2026
WASHINGTON — A pledge to “Make America Healthy Again” earned Robert F. Kennedy Jr. his job atop U.S. health agencies a year and some change ago. He’s now had the opportunity to turn his words into action, with mixed results.
“All one needs” to prove the health secretary’s attentiveness is to “review my unprecedented list of accomplishments on a wide range of issues, all of which I drove,” Kennedy posted on X on Wednesday in response to a journalist.
Can any of the new obesity medications in development stand out from the pack? Which company just broke records with its IPO? And will the Food and Drug Administration allow greater access to experimental peptides?
We discuss all that and more on this week’s episode of “The Readout LOUD,” STAT’s biotech podcast.
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