When the brain tracks time, it must decide whether its regions should rely on a shared timing signal or tack time separately. A recent study in Nature Communications provides evidence that the brain uses both approaches, switching between them depending on the situation.

A group at the Institute of Science Tokyo simultaneously measured the activity of thousands of neurons in two mouse brain regions and found that the areas sometimes shared timing information but maintained more independent representations at other times. The researchers, led by Associate Professor Riichiro Hira, maintained that this flexibility enables the brain to remain stable as it adapts to changing requirements.

A Task Built to Catch the Brain Switching Modes

Hira’s team created a task to highlight this timing mystery. They trained mice to expect rewards at intervals that switched between 6 and 12 seconds, without any break to mark the end of one trial and the start of the next. Since there was no pause, the mice had to keep updating their internal sense of time throughout the experiment, instead of resetting their mental stopwatch for each new trial.

The mice eventually figured out the pattern. At first they expected a reward every six seconds even if the time they had to wait was longer than this, but by the end of the training session, their behavior indicated that they had learned to anticipate both reward intervals. This showed that the mice were capable of keeping track of both durations and of predicting which one would come next.

While the mice performed the task, the researchers recorded activity in their secondary motor cortex and the posterior parietal cortex using wide-field two-photon calcium imaging. Both regions play key roles in planning, prediction, and working memory.

Two Regions, Two Kinds of Mistakes

The neurons fired in sequence in each brain area, with different cells becoming active at different times. This sequence showed that each region was monitoring the passage of time.

The researchers also identified two kinds of errors in the neural activity. In some cases, both areas made the same mistake when assessing the passage of time. These coherent errors suggested that both regions sometimes shared the same timing drift. In other instances, only one region was inaccurate while the other remained correct. These independent errors suggested that one region could temporarily maintain a different timing representation from the other. Independent errors were more frequent than coherent ones, and this ratio remained the same in all the mice examined.

If the brain regions were just randomly out of sync, you’d expect the ratio to change. However, it didn’t, which suggests that the brain has a built-in way to balance working together and working independently.

Modeling the Switch Between Coherence and Independence

To identify this mechanism, the team built a computational model with two recurrent neural networks linked by sparse, long-range connections and exposed to the same background noise. The model produced the same 2-to-1 ratio of independent to coherent errors seen in the mice.

The model also discovered that the limited connections between the networks tended to cause them to become synchronized, while the common noise caused them to move in separate directions. Hira provided an explanation of the interaction saying, “We found sparse inter-regional connectivity promotes synchronization between the two regions, whereas widespread fluctuations prevent complete synchronization, allowing each region to preserve its own temporal representation.” Neither force takes precedence; instead, a compromise is reached which allows communication between the regions.

The findings challenge the idea that brain regions rely on a single synchronized timing system. It indicates that the brain can adjust how different parts are coordinated, rather than just turning that coordination on or off.

What a Flexible Clock Could Mean for the Brain

Hira’s team believes that there are implications beyond simple timing circuits. “In the future, our results may contribute to a better understanding of cognition, neurological disorders involving disrupted inter-regional coordination, and the development of brain-inspired artificial intelligence and robotic control systems that combine stability with flexibility,” said Hira.

This last idea may prove most important in the years ahead. Engineers building AI and robotic systems face a similar challenge: how to let separate parts work on their own when needed, yet still come back into sync. The mouse brain shows that sparse connections and shared background fluctuations can achieve this balance. This could point to a design principle that even applies to systems with no biological components.

Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds an MBA, a Bachelor of Science in Business Administration, and a data analytics certification. His work focuses on breaking scientific developments, with an emphasis on emerging biology, cognitive neuroscience, and archaeological discoveries.

The United States Space Development Agency (SDA), in support of the U.S. Space Force, has awarded contracts to L3Harris Technologies and Sierra Space Corporation to build and deliver 36 Accelerated Missile Defense Tranche 3 (AMDT3) space vehicles (SVs) designed to operate in four distinct orbital planes.

Part of the Tracking Layer for Tranche 3 of the Proliferated Warfighter Space Architecture (PWSA), the space vehicles will support the White House’s space-based segment ‘Golden Dome for America’ antimissile defense system to expand the country’s missile tracking and defense network, with a projected delivery date of 2028.

36 Space Vehicles Orbiting in Four Separate Planes Will Aid Missile Defense

According to a statement announcing the awards, the 36 space vehicles will operate across four separate orbital planes. Half of the vehicles covering two of the four orbital planes will be made by Sierra Space Corporation. The statement from the SDA describes the vehicles as “missile warning/missile tracking” SVs loaded with specialized sensor packages. An official at the SDA speaking on background told The Debrief that the details of the sensor technologies and capabilities are not available at this time.

The second half of the vehicle order covering the other two orbital planes will be made by defense technology company L3Harris Technologies. Their award calls for 18 Hypersonic and Ballistic Tracking Space Sensor (HBTSS)-like missile defense variant SVs.

When The Debrief asked the SDA for clarification on the term “variant” space vehicles, the official explained that this designation represents the different types of sensor packages that each company will provide. For the L3Harris award, the SDA explained that their sensor is an advancement on earlier work performed with the Missile Defense Agency under the Hypersonic and Ballistic Tracking Space Sensor (HBTSS) program.

Infrared Sensors Will Integrate with a Low-Latency Communication Network

When discussing the significance of the twin awards, the SDA said their deployment will expand the company’s missile defense sensing established in previous phases “in support of homeland defense and theater defense.”

“Each AMDT3 SV will be interoperable with all SDA Tranche 1, Tranche 2, and Tranche 3 SVs and will operate in an integrated fashion through a common ground system,” the statement explained.

They also note that the tracking layer is equipped with infrared sensors “that will integrate with a low-latency communication network.”

“With these awards, SDA is accelerating the deployment of the Tracking Layer to provide the homeland, our deployed forces, and allies with global, persistent indications, detection, identification, warning, tracking, and defense against advanced and evolving missile threats,” explained G.P. Sandhoo, Space Force Portfolio acquisition executive for Missile Warning and Tracking and SDA director. “AMDT3 expands upon SDA’s previous and current Tracking Layer generations — Tranches 1, 2 and 3 — marking another milestone in delivering a resilient, global missile warning, missile tracking, and missile defense capability.”

Future Satellites Will Offer Even Greater Capability to the Warfighter

Although a specific delivery date for each of the company’s separate awards was not made public, the announcement did say they are expected to be available for launch “by the end of 2028.” Once aloft and in their respective orbital planes, the missile tracking and defense space vehicles will be operated and maintained by the U.S. Space Force.

When asked by The Debrief if there are any plans to add capabilities beyond detection and tracking to the multi-layer system in the future, the SDA said future improvements are one of the main pillars of the organization’s business model.

“We use spiral development to deliver new generations of satellites (we call them “tranches”) every few years,” the SDA explained. “Each new tranche represents an enhancement over the previous and offers greater capability to the warfighter, either through additional sensing coverage, or through technology advances (or potentially both).” 

Christopher Plain is a Science Fiction and Fantasy novelist and has spent the last six years as Associate News Editor and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him at christopher@thedebrief.org

ChatGPT Health is returning with substantially wider access, giving more iPhone users the option to connect information from Apple Health directly to the AI assistant.

The expansion follows a limited test introduced in January. OpenAI is now gradually making the dedicated Health experience available to eligible ChatGPT Free, Go, Plus and Pro users in the United States who are at least 18 years old.

Despite the close Apple connection, this is not a feature created by Apple or built directly into the Health app. OpenAI operates the service through ChatGPT, while Apple Health serves as one of the sources users can voluntarily connect.

Once permission is granted, ChatGPT can examine selected health and fitness information stored on iPhone, including activity, sleep, workouts and other measurements collected by compatible apps and devices. Users can then ask questions about changes over time without manually exporting records or uploading screenshots during every conversation.

ChatGPT Health Reaches More iPhone Users

ChatGPT Health originally appeared as a limited early-access experience for a small group of testers. The expanded rollout replaces that narrow availability with support for eligible adult users across the United States, although OpenAI says access may take several weeks to reach every account.

The feature works on the ChatGPT website and iOS app, but connecting Apple Health requires an iPhone. Users also need a recent version of the ChatGPT app before the Health option appears in the sidebar or More menu.

Apple Health is only one part of the system. ChatGPT can also connect to supported medical-record portals, One Medical and Function Health. Bringing those sources together allows the assistant to answer questions using a broader personal context than activity data alone.

A user could ask how sleep duration has changed across several weeks, whether workout frequency declined after a schedule change or how recent laboratory results compare with earlier tests. ChatGPT can also help organize questions before a medical appointment or summarize changes found across connected records.

Information from third-party fitness services can reach ChatGPT through Apple Health when those apps already share their data with the iPhone database. That may include measurements from platforms such as Garmin, Oura, Whoop, Strava and MyFitnessPal, depending on which categories each service makes available.

Not every proprietary score transfers. An app may calculate its own readiness, recovery or sleep score without writing that exact result into Apple Health. ChatGPT can only use the information made available through the connected source and approved by the user.

After synchronization, health information can inform responses throughout ChatGPT rather than remaining limited to conversations opened from the Health tab. The assistant normally asks for permission before using connected information, and users can also add “@Health” to a prompt when they specifically want a response based on their records.

Apple Health Data Gains a Conversational Layer

The appeal of the integration comes from turning a large collection of measurements into questions expressed in ordinary language.

Apple Health can already organize trends, highlights, medications, laboratory results and activity records. ChatGPT adds a conversational layer capable of comparing those categories or explaining them in a more personalized format.

Someone preparing for an annual physical could ask for a summary of meaningful changes since the previous appointment. A runner might request a comparison between training volume, sleep and resting heart rate. Another user could ask which information deserves discussion with a clinician after receiving new laboratory results.

That does not make ChatGPT a doctor. OpenAI says the feature is intended to support medical care rather than diagnose conditions or recommend treatment. Urgent symptoms and emergencies still require professional assistance.

The distinction is especially important because health data can appear more conclusive than it is. A change in heart rate, sleep or activity may have several explanations that cannot be determined from an iPhone record alone. Wearables can identify patterns, but they do not automatically reveal the medical cause behind them.

ChatGPT may help users notice relationships and prepare better questions. It should not be treated as the final authority on whether a symptom is harmless, whether medication should change or whether professional care is unnecessary.

The service is also read-only. ChatGPT can examine approved Apple Health information but cannot alter the original records stored on iPhone. It cannot add a diagnosis, change a medication list or write new measurements back into the Health app.

Users retain control over which Apple Health categories are shared. Someone may allow access to steps, workouts and sleep while withholding reproductive health, medications or other sensitive information.

That selective approach may be more appropriate than approving every category simply because the option is available. A useful response does not always require a complete health history.

Privacy Becomes the Central Decision

Connecting Apple Health to ChatGPT creates a different privacy relationship from using health features entirely within the Apple ecosystem.

Apple designs the Health app around on-device protections and user-controlled permissions. ChatGPT Health requires selected information to synchronize with OpenAI systems so the company can analyze it and generate personalized responses.

OpenAI says connected Apple Health data, medical records and conversations using that information are not used to train its foundation models or target advertising. The company also applies additional encryption and isolation protections to health information.

Users can disconnect Apple Health at any time. OpenAI says synchronized data from the disconnected source will be deleted from its systems within 30 days.

Previous conversations are handled separately. Information already included in ChatGPT conversation history remains until those chats are deleted, even after the Apple Health connection is removed.

Memory introduces another consideration. Conversations using Health can create memories when ChatGPT memory is enabled, although OpenAI says memories are not generated directly from synchronized health data. Temporary Chat or separate project memory can reduce how much personal context continues across future conversations.

The new Health experience should also not be confused with the existing ChatGPT integration inside Apple Intelligence. Siri and Writing Tools can use ChatGPT for certain requests without requiring the dedicated ChatGPT app or a connected account.

ChatGPT Health is a separate OpenAI service with its own account, permissions, privacy controls and health-data connections. Using ChatGPT through Siri does not automatically give OpenAI access to Apple Health.

That separation gives users a meaningful choice. They can continue keeping health information inside Apple apps, share only selected categories with ChatGPT or connect medical records for a more comprehensive view.

The expanded rollout makes one of the most personal databases on iPhone available to conversational AI. Its usefulness will depend not only on the quality of the answers, but also on whether users understand exactly which information they are sharing and where it goes after leaving the device.

The post ChatGPT Health Expands Apple Health Access appeared first on AppleMagazine.

I dispense what might be called valuable insight to my friends, as well as in this public forum. My friends know the danger: they might become the topic of a column, which is true for my buddy Jeff, who left a bag containing his passport behind at a hotel. Fortunately, he had an AirTag in his bag. That was, however, just the beginning of the journey. (Jeff gave me permission to share his story.)¹

To avoid suspense, I’ll tell you that Jeff doesn’t have his bag back, but will soon.

Grate news

Jeff was out of town on business for a few days—he’s one of those nearly extinct creatures called a “full-time technology reporter“—and was carrying his passport to Texas not because it’s another country (it hasn’t seceded yet), but because he lacks a Real ID-upgraded driver’s license. He had a small bag with a few items, including the passport and an AirTag, that he didn’t need to carry, so he used the hotel safe. There have been many articles written about how unsafe hotel safes are, but it feels as if you’re in a decent hotel, it’s still another bar for someone to get through to steal your stuff.

Leaving in a bit of a rush, Jeff didn’t retrieve the bag from the safe. When he realized it wasn’t with him, thousands of miles later, he was peeved. Shouldn’t the “left behind” feature in Find My have alerted him? Find My showed the bag’s location, however. For some reason, it appeared as if it were in the hotel parking lot. I catastrophized with him, assuming it was stolen. He called the hotel, which said it wasn’t in lost and found.

A staff member went out, looked in the parking lot, and said the rough location was a grate—perhaps the bag had been stolen and someone had found the AirTag and dropped it through the slats? Which would imply that a hotel employee or a thief had managed to get into Jeff’s room after he left, open the safe, leave the hotel, and rummage through the bag in the parking lot before absconding.

That wasn’t the case (or valise). The hotel called back the next day. The previous staffer didn’t know, for some reason, that valuable left-behind items were tagged and placed in a safe in the basement, presumably below or near the parking lot. His bag, containing his passport and other items, would be sent back to him.

Jeff’s experience reveals several aspects of the Find My tracking system that you can take advantage of in advance or use if you’ve lost something or left it behind.

Don’t leave me!

Every device and item you have can be set to alert you when you “leave it behind.” I believe this setting is enabled by default, though Apple’s documentation isn’t clear on this point. All of my devices and items have it enabled, and Jeff found it was turned on for all his gear. Here’s how to check:

1. In a native Find My app, select the device (like a Mac) or an item (an AirTag or other Find My network item) in the list of such things.
2. On an iPhone, iPad, or Apple Watch, the action sheet appears. On a Mac, click the info (i) icon next to the item’s name on the map. In the upcoming version 27 operating system releases on all platforms, tap or click the More (…) button that appears when you select the device from the list.
3. Tap or click Notify When Left Behind, which should already show On. (In the 27 releases, tap or click When Left Behind.)
4. If disabled, turn it on.

Here’s a crucial detail: examine the “Notify me, except at” list. You can manually add to this set of locations (tap or click New Location). However, it primarily grows when you’re notified by an item or device being left behind, and then you tap or click in the notification to ignore it at that location. You are presented with the option to just exclude that item or device from that location or all of your equipment.

It’s very easy to approve that exclude-all button. (Jeff did not; his list didn’t include the hotel.) This can be convenient when you’re at a hotel, a friend’s house, or another location for a few days or frequently, and sometimes leave Find My-tracked stuff there. But once you ignore the location, you won’t get notified in the future. You can modify the list by hand, too.

Jeff may instead have been tripped up by the safe acting as a Faraday cage—a metal mesh or box that shields electromagnetic signals from passing through. The AirTag and other Find My items use Bluetooth to broadcast a rotating identifier at regular intervals.² If the safe blocked that signal, Jeff’s iPhone lost contact with the AirTag the moment the bag went in—a few days before he left. With no fresh separation between the phone and the item at departure time, the alert may have lacked the necessary trigger. Jeff was on the verge of sharing the location with the hotel when they found it.

Apple says this takes longer than the few days Jeff was on his trip: “You can see its last known location for up to seven days in the Find My app.” After seven days, the device or item’s location will appear as “No location found” or “Offline.” Jeff could see the item’s location, which made the lack of notification seem like a bug.

Now for the grate part (not great part): once Jeff’s bag was removed from the safe in his former room, it would have been carried through the hotel and detected by every iPhone, iPad, or Mac nearby. When it reached the hotel’s lost-and-found safe, the rough location would likely still be relatively close before it entered that particular Faraday cage. At which point, when Jeff looked at Find My, he saw it at (or under) the parking lot.

Sack attack

The hotel works with a service that handles the return. Jeff paid both a whopping and reasonable $60 to have it sent two-day air back to him. Fair enough! Unfair enough, days after he paid, the bag is still at the hotel (as I write this). Jeff will, of course, follow its progress via Find My.

[Got a question for the column? You can email glenn@sixcolors.com or use /glenn in our subscriber-only Discord community.]

Safari Notify Me gives Apple’s browser a useful new role in online shopping: watching a product page after the shopper has closed it. Instead of repeatedly returning to check whether an item is available or whether its price has changed, users can ask Safari to monitor the page and send an alert when the requested update appears.

The feature arrives as online shopping becomes increasingly fragmented. Prices can change several times during a promotion, popular items disappear within minutes and retailers often require shoppers to join separate mailing lists for availability alerts. Dedicated tracking apps can help, but each adds another account, extension or subscription.

Safari Notify Me places the monitoring tool inside the browser already being used to view the product. It is simple enough for occasional purchases while potentially useful for expensive electronics, limited releases, event registrations and products that move in and out of stock.

Safari Notify Me Watches the Page for You

Safari Notify Me is designed to monitor changes on a specific webpage. The user identifies what should be watched, such as a lower price, a product returning to stock or registration becoming available. Safari then checks the page and sends a notification after detecting the relevant change.

Apple has presented price changes and product restocks as central examples, though the feature is not restricted to shopping. It may also help with reservations, ticket availability, enrollment openings or other pages where one detail changes over time.

For shopping, the advantage is immediate. A customer can leave the product page without relying on memory, leaving dozens of tabs open or refreshing the site throughout the day.

The browser becomes temporarily responsible for the follow-up.

This differs from a retailer’s own email alert. Store notifications usually depend on the business offering the feature, and they may focus only on inventory. Safari can monitor the page according to the user’s request, potentially covering price and availability without requiring another marketing subscription.

How Safari Price Alerts Help

Online prices are rarely as stable as the label suggests. Retailers adjust discounts, respond to competitors, launch short promotions and change prices according to stock levels.

A shopper interested in a Mac accessory, appliance or expensive display may not want to purchase immediately at the listed price. Checking the page every day is inefficient, while joining a store mailing list can produce far more promotional email than useful information.

Safari price alerts create a quieter alternative. The user can identify the product and wait for the browser to report a meaningful change.

The feature does not replace price history. Safari may detect that the amount has dropped, but that does not necessarily prove the new price is the lowest offered during the year. Dedicated price-tracking services may still provide charts, comparisons and retailer-specific history.

Safari Notify Me is better understood as a page-change assistant. It tells the shopper that something requested has happened. The decision to purchase remains with the user.

Restock Alerts May Be Even More Useful

Restock monitoring may become the feature’s strongest shopping use. Limited products can return without warning and sell out before a retailer’s email reaches every subscriber.

This often happens with game consoles, graphics hardware, collectibles, seasonal products, concert merchandise and popular configurations of newly released devices. Size and color variations can also return separately, making a general product alert less useful.

Safari restock alerts can focus on the page the user is already viewing. A notification provides a reason to return without requiring the tab to remain open.

The browser cannot reserve the item or guarantee that inventory will remain available. A notification may also arrive after other buyers have begun ordering. Safari removes the repeated checking, but it does not control the retailer’s inventory system.

That limitation is reasonable. Notify Me helps users notice the opportunity; it does not turn Safari into an automated purchasing bot.

Using Safari Notify Me

The feature is intended to require little setup. Users begin on the relevant product or registration page and tell Safari which change they want it to watch.

To create a Safari Notify Me alert:

Open the webpage in Safari > Select Notify Me > Describe the price, availability or page change to monitor > Allow Safari notifications when requested

The exact options shown may depend on the device, webpage and software version. Apple is introducing the feature with its new operating-system releases, and availability may vary by language or region.

A useful request should be specific. Asking Safari to report when the item returns to stock is more actionable than asking for any page change. For price monitoring, the user may request a reduction or watch for a particular target when the page supports enough information.

Once the alert is active, there is no need to keep the product page open. Safari sends a notification after detecting the requested update, allowing the user to return directly to the page.

A Better Use for Apple Intelligence

Safari Notify Me is a practical example of Apple Intelligence operating as an assistant rather than a writing tool. It interprets what the user wants, watches for a future condition and reports back when that condition appears.

The feature does not need to generate a long answer or place a chatbot beside every shopping page. Its value comes from removing a repetitive task.

That restrained approach fits Safari. The browser already manages passwords, private browsing, tab organization, Reader and tracking protections. Monitoring a page extends that utility without turning Safari into a retailer or shopping marketplace.

It may also reduce the need for third-party extensions among casual users. Someone who occasionally watches one product does not necessarily need a dedicated deal platform with wish lists, affiliate links and account registration.

Specialized services will remain useful for serious bargain hunting. Safari covers the simpler request: tell me when this exact page changes in the way I care about.

Notifications Need Restraint

Any feature built around alerts can become noisy when used too freely. Monitoring every product considered during casual browsing could fill Notification Center with price changes and restocks that no longer feel relevant.

Safari Notify Me works better when reserved for purchases with genuine intent. A few focused alerts are easier to understand and act upon than dozens of loosely defined page watches.

Users should also remove alerts after buying the item or losing interest. A notification for a product purchased weeks earlier adds clutter without saving time.

Safari notifications can be managed through the device’s normal notification settings. Disabling all Safari alerts may also silence other useful browser notifications, so reviewing individual watches inside Safari is preferable when available.

Price Is Not the Only Shopping Decision

A lower price can encourage a quick purchase, but shoppers should still review the seller, return policy, warranty and delivery estimate. Notify Me reports a page change; it does not evaluate whether the store is reliable or whether the offer has hidden conditions.

A product may return through a third-party marketplace seller at a higher price. A discount may apply only after a membership, coupon or trade-in. Limited inventory can also create pressure to buy before reading the terms.

Safari’s privacy protections and fraud warnings remain relevant, but users should confirm that the page belongs to the intended retailer before entering payment information.

The alert is a starting signal, not an endorsement.

Safari Becomes More Useful After the Tab Closes

Browsers traditionally stop being helpful once users leave a page. Safari Notify Me changes that relationship by allowing selected pages to remain useful without remaining visible.

For shoppers, that means fewer repeated searches, fewer forgotten products and less dependence on promotional email. Price and restock alerts can operate quietly until there is a reason to return.

The feature will not replace advanced shopping trackers, and it cannot guarantee inventory. Its appeal is that most users do not need those larger systems for every purchase.

Sometimes the entire shopping problem is waiting for one price to fall or one button to change from unavailable to buy. Safari Notify Me allows the browser to handle that wait.

The post Safari Notify Me Makes Online Shopping Easier appeared first on AppleMagazine.

The Samsara Tracking Label hides a BLE system that can offer real-time location in a disposable package.

Meta’s Mouse-Tracking Pause Meta has switched off a program that quietly watched its own staff work. On Monday,

Clair Health will track inflammation and bloating markers, energy levels, and cycle phase classification to give insights into cycle irregularities and perimenopause, as well as hormonal fluctuations, and how to navigate those changes.

In a groundbreaking advance for microbiome science and viral ecology, researchers at Rice University have unveiled a revolutionary RNA barcoding system that reveals intricate interactions between bacteriophages—viruses that infect bacteria—and their bacterial hosts within complex microbial communities. This novel technique, recently described in the prestigious journal Nature Communications, offers an unprecedented lens through which scientists can decode the vast and hidden landscape of phage-host dynamics, potentially transforming microbiome engineering and therapeutic interventions.

Bacteriophages, the most abundant biological entities on our planet, orchestrate microbial ecosystems by infecting bacteria, altering their metabolic functions, and facilitating horizontal gene transfer—a natural mechanism for distributing genetic material across bacterial populations. Despite their ubiquity and ecological importance, unraveling which specific phages interact with which bacterial hosts in natural and engineered environments has remained an elusive challenge, primarily due to limitations in traditional culture-based methods and the complexity of microbial consortia.

The team, led by Lauren Stadler, Associate Professor of Civil and Environmental Engineering at Rice University, has pioneered a synthetic biology platform leveraging RNA-addressable modification, originally designed to monitor gene transfer via bacterial conjugation. Central to this approach is an engineered ribozyme that inserts unique molecular barcodes directly into the 16S ribosomal RNA of bacterial recipients following successful DNA transfer from a phage. This molecular tagging allows precise identification of host organisms through RNA sequencing, bypassing the need for labor-intensive bacterial culturing and enabling high-throughput analysis directly within environmental samples.

Applied to the well-characterized bacteriophage P1—known for its DNA transfer capabilities among enteric bacteria—the system revealed not only anticipated host range patterns but also uncovered a surprising new group of hosts in environmental wastewater samples: members of the order Aeromonadales, including Aeromonas hydrophila. This finding is particularly striking given that Aeromonas hydrophila had not previously been identified as a P1 host, underscoring the technology’s capability to unmask previously hidden phage-bacterial relationships within complex ecosystems.

The ability to detect these cross-order interactions is more than a mere academic curiosity; it offers critical insights into gene flow mechanisms that may fuel the spread of antibiotic resistance and influence microbial community stability. Traditional methodologies often confuse surface attachment of phages with genuine infection and DNA transfer. However, the RNA barcoding approach distinctly traces successful transduction events, allowing researchers to discriminate true host interactions from transient viral contacts.

Moreover, the Rice research team demonstrated that subtle genetic variations in phage tail fibers—protein structures critical for host recognition and binding—can drastically redefine a phage’s host range. By engineering phage particles with different tail fiber compositions and deploying their barcoding system within wastewater microbial consortia, they mapped how each fiber variant targeted a unique subset of bacteria. These insights provide an invaluable blueprint for designer phages with tailored host specificity, potentially catalyzing advancements in phage therapy and targeted microbiome modulation.

The implications of this technology extend far beyond wastewater treatment plants. As microbiome research continues to gain momentum in medicine, agriculture, and environmental science, the ability to efficiently monitor and understand viral gene exchange pathways promises to accelerate the development of phage-based alternatives to antibiotics, precision microbiota editing, and enhanced bioremediation strategies. Because the system is compatible with standard amplicon sequencing techniques, it lends itself to scalable deployment for large environmental surveys and clinical studies alike.

This innovative research was carried out through an interdisciplinary collaboration spanning Rice University’s civil and environmental engineering, biosciences, bioengineering, and chemical and biomolecular engineering departments, as well as the Systems, Synthetic and Physical Biology Graduate Program. The team included notable contributors such as James Chappell, associate professor of biosciences, and Jonathan Silberg, Stewart Memorial Professor of BioSciences, alongside doctoral graduate Zachary LaTurner—now a postdoctoral researcher at UC Berkeley’s Innovative Genomics Institute—and Rice graduate students Matthew Dysart, Samuel Schwartz, and Elizabeth Zeng.

In a broader context, this study spotlights the transformative potential of synthetic biology tools to decode biological complexity, enabling researchers to untangle the dense web of microbial interactions that govern health and disease in humans, animals, and natural environments. By providing a scalable, sensitive, and accurate method to chart phage-host relationships, the RNA barcoding system represents a major leap forward—a new frontier in the quest to harness viruses as precision instruments in biotechnology and medicine.

As bacteriophages gain recognition as powerful alternatives to traditional antimicrobial therapies amidst rising antibiotic resistance, tools like this RNA-based system will be crucial for understanding and safely deploying phage interventions. The meticulously engineered approach that allows direct observation of viral gene transfer events opens avenues for designing phages that deliver beneficial genes or selectively eliminate harmful microbial species with surgical precision, revolutionizing future therapeutic and environmental applications.

Rice University’s pioneering work injects fresh momentum into the fast-evolving field of microbiome science, providing a versatile, high-throughput technique to explore viral influences on bacterial populations in situ. This innovation promises to inspire a wave of research initiatives aimed at mapping the viral “dark matter” within microbiomes—complex microbial ecosystems influencing global biogeochemical cycles, human health, and industrial processes.

As scientists embrace this RNA barcoding platform, the microbial world’s hidden dialogues—encoded in viral gene transfers—may soon be decoded with clarity and scale that were previously unimaginable. Unlocking these intricate viral-bacterial conversations not only enriches our fundamental understanding of microbial ecology but also propels the design of next-generation biotechnologies, setting the stage for a paradigm shift in how we interact with the microbiome and its viral inhabitants.

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Subject of Research: Bacteriophage-host interactions and microbial gene transfer dynamics using RNA barcoding technology

Article Title: Cross-order detection of bacteriophage transduction in microbial communities using RNA barcoding

News Publication Date: 23-Mar-2026

Web References: https://www.nature.com/articles/s41467-026-70995-y

References: DOI 10.1038/s41467-026-70995-y

Image Credits: Rice University

Keywords

Bacteriophages, RNA barcoding, microbial communities, bacteriophage host range, synthetic biology, horizontal gene transfer, phage therapy, wastewater microbiology, microbial ecology, viral-host interactions, microbiome engineering, DNA transduction

In a groundbreaking advance at the intersection of bioengineering and microbiology, researchers at Harvard’s John A. Paulson School of Engineering and Applied Sciences have unveiled a pioneering device known as a pico-calorimeter. This remarkable instrument is capable of directly detecting heat signals emanating from minute populations of living cells, a feat that until now has remained technologically elusive due to the vanishingly small scale of these thermal signatures. By enabling real-time metabolic tracking at unprecedented sensitivity, the pico-calorimeter promises to revolutionize our understanding and monitoring of cellular activity, bacterial growth, and antibiotic response.

At the core of this innovation is the principle that living cells, as they metabolize nutrients, grow, divide, and react to external stimuli such as drugs, intrinsically emit heat. This metabolic heat, although incredibly subtle, offers a direct, unmediated insight into the physiological state of cells. Unlike conventional methods that infer cellular metabolism indirectly through oxygen consumption or chemical byproducts, the pico-calorimeter provides a direct calorimetric measurement, offering a more immediate and accurate assay of cellular energetics.

The technical architecture of the device is a marvel of microengineering. It consists of three ultrafine glass capillaries aligned on a delicately micromachined membrane with near-atomic precision. One of these capillaries harbors the biological sample suspended in a liquid growth medium, while the remaining two serve as thermodynamic reference points. As the bacteria or other cells within the sample metabolize and proliferate, they release minute quantities of heat. This thermal flux generates infinitesimal temperature gradients relative to the reference capillaries, which are then transduced into electrical signals by a nearby thermopile—an exquisitely sensitive heat-to-electricity converter capable of resolving fluctuations on the order of picowatts.

A critical enhancement in this iteration of the pico-calorimeter lies in its housing within a vacuum chamber. This vacuum environment thermally isolates the sensor assembly from ambient thermal noise, dramatically amplifying sensitivity by nearly an order of magnitude compared to antecedent designs. The prior versions employed liquid droplets on suspended membranes, which, while innovative, presented operational challenges and limited sensitivity. The current vacuum-sealed, microfluidic integration advances robustness, usability, and measurement fidelity, marking a milestone in the delicate art of thermal detection at the cellular scale.

Demonstrating the device’s prowess, the research team employed the pico-calorimeter to monitor Escherichia coli growth dynamics, beginning with an initial seed population as modest as thirty to forty individual bacterial cells. This capability to detect and analyze such small biological communities unveils immense potential for applications ranging from fundamental microbiology to clinical diagnostics. Notably, the device was employed to examine bacterial metabolic responses upon introduction of antibiotics with varying mechanisms of action—chloramphenicol, rifampicin, and ampicillin—capturing differential heat signatures indicative of altered cellular viability and activity.

These direct calorimetric measurements have revealed metabolic perturbations well in advance of what traditional culture-based microbiological assays could discern. This capability is particularly transformative in clinical scenarios such as sepsis, where detecting and characterizing bacterial populations at extremely low concentrations in blood is vital but presently time-consuming. The pico-calorimeter’s sensitivity could drastically truncate diagnostic timelines from days to hours, allowing more timely and targeted antimicrobial interventions.

Beyond measuring growth and antibiotic susceptibility, the pico-calorimeter enables continuous, real-time monitoring of fundamental cellular parameters including viability, proliferation rate, and stress responses. This temporal resolution offers researchers the invaluable ability to dynamically track cellular states and transitions, capturing metabolic shifts as cells respond to environmental perturbations or pharmacological treatments. Such insights may open new frontiers in cell biology, pharmacodynamics, and personalized medicine.

This breakthrough device represents the culmination of roughly two decades of meticulous research in the Vlassak laboratory, with contributions building from initial exploration of nano-calorimetry techniques aimed at materials science phenomena such as phase transitions in shape memory alloys and metallic glasses. The interdisciplinary bridge extended to biological systems has ushered in ultrasensitive calorimetry methods capable of assessing metabolic heat production in large cells and complex embryonic development processes, laying foundational expertise for this current bio-calorimetric leap.

Technologically, the fabrication of the pico-calorimeter draws upon state-of-the-art micro- and nanofabrication facilities, including the Harvard Center for Nanoscale Systems. The integration of microfluidics and micromachined sensing elements within thermally isolated environments exemplifies the cutting-edge convergence of materials science, electrical engineering, and biological instrumentation. The multidisciplinary synergy underscores the technological sophistication essential for detecting thermal signals billions of times smaller than everyday heat fluxes.

Commercially, the Harvard Technology Development office has filed multiple patents covering the pico-calorimeter and its applications in antimicrobial susceptibility testing. Juanjuan Zheng, a pivotal figure in this research and founder of an innovative startup, is leveraging the technology to deliver practical, label-free, real-time metabolic readouts. These tools hold promise for broad adoption in life sciences research, pharmaceutical development, and clinical diagnostics, harnessing the power of heat measurement to glean functional insights from minute biological samples.

As the research community embraces this transformative platform, interest has surged from a diverse array of scientific domains. The ability to capture direct metabolic information from tiny, dynamic living systems resolves a long-standing challenge in single-cell and small-population analysis. This heralds a new era where functional metabolic data provides early and actionable information on biological states, ranging from cellular growth and stress response to drug efficacy and resistance patterns.

In essence, the Harvard pico-calorimeter transcends conventional bioanalytical tools by transforming infinitesimal heat emissions into a vivid metabolic narrative. This technological breakthrough not only augments our scientific toolkit but also possesses the potential to accelerate biomedical discovery, enhance therapeutic precision, and ultimately improve patient outcomes by enabling rapid, noninvasive interrogation of cellular function. The implications for healthcare, research, and biotechnology are profound, heralding an exciting frontier where the subtle warmth of life becomes an unequivocal signal of cellular health and response.

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Subject of Research: Cells
Article Title: A pico-calorimeter for cellular metabolism and antimicrobial susceptibility testing
References: Proceedings of the National Academy of Sciences
Image Credits: Vlassak Group / Harvard SEAS
Keywords: Calorimetry, Chemical analysis, Life sciences, Biophysics, Single cell profiling, Single molecule analysis, Materials science, Physics, Applied sciences and engineering, Applied physics, Engineering, Electrical engineering, Chemical engineering, Mechanical engineering, Health and medicine, Biomedical engineering