Comment

Comment by Dr. Krishna Kumari Challa yesterday

Keeping bacteria contained with a stiffer, tougher scaffold
The researchers involved in the new study identified two main aspects of existing hydrogel scaffolds that needed improvement. They wrote, "We hypothesized that fulfilling two key criteria for a material enables robust and durable containment of therapeutic bacteria: (i) resistance to the internal forces generated by proliferating bacteria and (ii) mechanical toughness sufficient to withstand deformation from surrounding tissues."

And so, the team engineered an implantable polyvinyl alcohol (PVA) hydrogel with optimized stiffness and toughness to keep expanding colonies from breaking through and to resist breakage under body movement. They then embedded engineered E. coli bacteria in protective microgels within it.

The team then tested out the new scaffold in various situations. They allowed the encapsulated bacteria to sit in a nutrient broth in the lab for six months, checking in on it frequently to see if any bacteria leaked out. But the scaffold held the bacteria for the entire six-month period.

They also evaluated fatigue resistance using cyclic crack growth testing, which tests how fast a flaw grows in a material under repeated loading. The PVA material showed a high fatigue threshold that indicated a 10-fold improvement over previous agarose-based materials. The new scaffold material also outperformed agarose in mechanical robustness testing and showed that the bacteria remained inside and functional under stress.
The new ILM material was then tested out as a local drug depot in a mouse model. The mice were implanted with a pin containing the ILM and then infected with a bacteria called Pseudomonas aeruginosa, which is common in implant surgeries and known for having an inherent resistance to many common classes of antibiotics. The bacteria in the scaffold were engineered to detect P. aeruginosa and release a drug to treat the infection.

The mice implanted with the new ILM material and engineered bacteria showed significantly reduced infection, compared to controls. Engineered bacteria inside the ILM were able to successfully detect infection signals and release the antimicrobial proteins to treat the infections in mice.

The team also performed testing on cancer cells in the lab, which showed successful drug delivery using the new materials. They write, "To evaluate platform versatility beyond antimicrobial therapy, we tested ILMs in a cancer-relevant context. Conditioned media from ILMs encapsulating Escherichia coli ClearColi (Ecc) engineered to express an inducible pore-forming toxin significantly reduced viability of CT26 cancer cells compared with GFP controls."

These results represent a big step in safer microbe-based drug delivery, although long-term safety and immune responses in humans still need to be studied. Further studies will also be helpful for determining potential effects or efficacy of chronic use and broader disease applications.

Tetsuhiro Harimoto et al, Implantable living materials autonomously deliver therapeutics using contained engineered bacteria, Science (2026). DOI: 10.1126/science.aec2071

Part 2

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Comment by Dr. Krishna Kumari Challa yesterday

Implantable bacteria can now be safely contained, clearing a major hurdle for fighting infection and cancer

Researchers have long known that bacteria could potentially be used to deliver therapeutic drugs inside the human body. However, safely and successfully carrying out such a feat in humans has been a challenge. But now, researchers  have made another step forward toward the goal of using microbes as medicine. Their recent study, published in Science, details a novel method for containing engineered bacteria to keep them from infecting their host while still successfully delivering potentially life-saving medications.

Researchers have had success in engineering implantable bacteria that can sense infections and then release medications to kill other bacteria or cancer cells. These engineered bacteria must still be contained, however, to prevent dissemination and toxicity.
To do this, attempts have been made using hydrogels to encapsulate the engineered bacteria, but these often failed to prevent escape over time due to increasing pressure from expanding bacterial colonies or under physical stress from the body. Genetic containment strategies have also been attempted, but often fail due to evolutionary changes in the bacteria over time.

Yet, the idea of bacteria as living therapeutics is still attractive to scientists because of their ability to colonize a wide range of physiological environments, such as mucosa, infected sites, skin, inflamed tissues and tumors, and the ability to deliver therapeutics in response to specific biological signals, as opposed to waiting until symptoms become noticeable in a compromised person. Still, a long-term, biocompatible solution that keeps bacteria confined while allowing them to function as drug factories is crucial for these implantable living materials (ILM) to provide reliable, safe therapies.

Part 1

Comment by Dr. Krishna Kumari Challa yesterday

How the brain recombines past knowledge for flexible planning

When facing new situations or problems, humans typically rely on knowledge they acquired in the past. Specifically, neuroscience studies suggest that the brain reorganizes past experiences and previously acquired knowledge, creating mental frameworks that can help humans to solve the problems they are facing. The recombination of past knowledge into new mental structures also allows humans to flexibly plan future actions in changing environments. Past studies suggest that two key brain regions contribute to this process, the hippocampus and the medial prefrontal cortex (mPFC).

The hippocampus is a brain structure that plays a key role in the formation of memories and spatial navigation. The mPFC, on the other hand, is known to support decision-making, planning, reasoning and the integration of information.

Researchers  recently set out to investigate how the hippocampus and mPFC work together to combine past knowledge into new configurations. Their findings, published in Nature Neuroscience, suggest that this process is supported by brief bursts of high-frequency neural activity in the hippocampus, called hippocampal ripples, and the replay (i.e., re-activation) of past experiences in the brain.

The human brain excels at solving novel problems by flexibly recombining a limited set of familiar elements, often through the internal planning of sequences that assemble these elements into new configurations.

The researchers  analyzed brain activity recordings collected by the electrodes in the participants' brains during the experiment. This allowed them to understand how brain activity changed while the participants were combining past knowledge to complete the task at hand.

The brain activity patterns observed by the researchers suggest that the hippocampus and mPFC closely coordinate to recombine familiar pieces of information into new mental structures. Short bursts of brain activity (i.e., ripples) in the hippocampus appear to help the brain to reorganize stored memories.

During these ripple events, the brain appears to rapidly replay sequences of information, reorganizing familiar building blocks into new combinations that are useful for solving the problem/task at hand. Concurrently, the mPFC appears to update its activity patterns to represent the newly identified solution to a problem.

Hippocampal ripples shift mPFC representations toward the inferred relational configuration, facilitated by replay that reorganizes building blocks into candidate sequences," wrote the authors. "Replay is strongest during ripple periods, closely coordinates with mPFC activity and is predictive of efficient inferential behavior. Together, hippocampal ripples and replay emerge as a key mechanism for dynamically updating cortical representations online to support planning and inference."

This recent study offers new insight into how the human brain flexibly combines past knowledge to creatively tackle new tasks or problems.

Li He et al, Human hippocampal ripples coordinate planning sequences and compositional representations in neocortex, Nature Neuroscience (2026). DOI: 10.1038/s41593-026-02291-3

Comment by Dr. Krishna Kumari Challa yesterday

Physicists created hybrid light-matter particles that interact strongly enough to compute

Hybrid light-matter quasiparticles called exciton-polaritons, formed by coupling photons with electrons in atomically thin semiconductors, enable strong light interactions sufficient for all-optical signal switching. This approach achieves switching at extremely low energy levels (~4 quadrillionths of a joule), potentially enhancing photonic chip efficiency and supporting direct optical processing and quantum computing functions.

Zhi Wang et al, Strongly Nonlinear Nanocavity Exciton Polaritons in Gate-Tunable Monolayer Semiconductors, Physical Review Letters (2026). DOI: 10.1103/gc15-qsvf

Comment by Dr. Krishna Kumari Challa on Friday

India’s DNA map uncovers millions of missing genetic variants A vast study reveals deep diversity, hidden disease risks and exposes the limits of Eurocentric medicine.

India’s DNA map reveals amazing diversity
India’s biggest gene-sequencing effort has shed new light on the diversity of the population, identifying nearly 130 million genetic variants, almost a third of which have not been reported previously. The GenomeIndia project analysed the whole genomes of almost 10,000 people, uncovering 44 million variants that weren’t already in global scientific databases. The study also revealed genetic risk factors in some populations, such as variants in genes that affect how the body processes certain drugs, variants linked to anaesthesia-related complications and extremely high levels of genetic homozygosity — when individuals inherit identical forms of a gene at a particular chromosome location from both parents. This can be a risk factor for recessive genetic diseases.

https://www.medrxiv.org/content/10.64898/2026.03.20.26348801v1

https://www.nature.com/articles/d44151-026-00082-0?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on Friday

Are microbes the future of pollution clean-up?
Synthetic biologists are engineering bacteria to feast on oil, plastic and toxic chemicals

Microbes eat pollution — if we let them
A growing community of synthetic biologists are using biotechnology-led solutions — mostly microorganisms containing DNA tailored for a specific function — to tackle pollution ranging from microplastics and industrial waste to soils laced with heavy metals or explosive residues. But the field is held back by concerns around releasing genetically modified organisms into the environment, and the fact that current incentives make polluting profitable while cleaning up costs money.

https://www.nature.com/articles/d41586-026-01420-z?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on Friday

Autoimmune gene provides viral protection

A variant of the gene PTPN22 linked to autoimmune diseases also appears to have a protective effect against viral infections. Researchers found that in mice, the presence of this variant kick-starts the activity of natural killer cells against a type of coronavirus. Removing natural killer cells from mice without the mutation had no effect on their ability to fight off the infection, which suggests these cells are not usually involved in the antiviral response. The findings could explain why this variant is relatively common in people, despite its link to diseases such as diabetes and lupus.

https://www.pnas.org/doi/10.1073/pnas.2519903123

Comment by Dr. Krishna Kumari Challa on Friday

Prenatal exposure to chemical mixtures may influence fetal growth through the placenta

Prenatal exposure to mixtures of environmental chemicals, particularly low molecular weight phthalates, is associated with lower birthweight and altered fetoplacental blood flow, potentially mediated by imbalances in angiogenic biomarkers. Organophosphate mixtures correlated with higher foetal weight, possibly reflecting dietary factors. These findings indicate that chemical mixtures may influence foetal growth via placental mechanisms.

Bethany Knox et al, Prenatal Exposure to Mixtures of Nonpersistent Endocrine-Disrupting Chemicals and Angiogenic Biomarkers, Placental Function, and Fetal Growth, Environmental Science & Technology (2026). DOI: 10.1021/acs.est.5c13234

Comment by Dr. Krishna Kumari Challa on Friday

Common NSAIDs in first trimester show no birth defect link, data suggest
First trimester exposure to common NSAIDs, including ibuprofen, diclofenac, and naproxen, was not associated with an increased risk of major congenital malformations or defects in specific organ systems. No significant dose-response relationship was observed, indicating NSAID use in early pregnancy does not elevate birth defect risk.
Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, taken during the first trimester of pregnancy are not associated with an increased risk of major birth defects, according to a new study published in PLOS Medicine.
Pain and fever are common in early pregnancy and the options to manage them have been limited. Studies have raised safety concerns regarding acetaminophen while data on the safety of NSAIDs—which include widely used medications such as ibuprofen, diclofenac, and naproxen—has remained inconclusive.

The new study used data from the Southern Israeli Pregnancy Registry (SiPREG) to analyze 264,858 singleton pregnancies between 1998 and 2018, of which 20,202 (7.6%) were exposed to NSAIDs during the first trimester—most commonly ibuprofen (5.1%), diclofenac (1.6%), and naproxen (1.2%).

Major congenital malformations were identified from linked clinical, hospitalization, and termination records. The researchers adjusted risks for maternal and pregnancy characteristics including maternal age, ethnicity, diabetes, obesity, folic acid use, and the reason for NSAID use.

NSAID exposure was not associated with major congenital malformations overall (8.2% vs. 7.0% in unexposed pregnancies; matched adjusted relative risk = 0.99), nor with malformations in specific organ systems including the cardiovascular, musculoskeletal, central nervous system, gastrointestinal, and genitourinary systems.

No association was observed for any individual drug, and dose-response analyses found no significant link between cumulative NSAID exposure and birth defect risk.
The results provide reassuring evidence that NSAID use in early pregnancy is not associated with major birth defects.

Hasidim AA, et al. First-trimester nonsteroidal anti-inflammatory drugs exposure and risk of major congenital malformations: A retrospective register-based cohort study, PLOS Medicine (2026). DOI: 10.1371/journal.pmed.1005063

Comment by Dr. Krishna Kumari Challa on Friday

When words look like their meaning, we process them faster, new research reveals
Words whose visual letter shapes resemble their meanings—demonstrating visual iconicity—are processed more quickly and accurately, even after controlling for word frequency, length, and concreteness. Words for round or spiky objects rated higher in iconicity when containing correspondingly shaped letters, and such words are typically learned earlier. This suggests that visual features of written words can facilitate language processing.

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