The research, led by Peng Zhao, Mengyuan Chen and Ying Kang under the corresponding authorship of Yongfeng Hu and Fan Yang at the NHC Key Laboratory of Systems Biology of Pathogens, part of the Chinese Academy of Medical Sciences and Peking Union Medical College in Beijing, set out to overcome three long-standing obstacles in anellovirus research: fragmented reference datasets, inconsistent taxonomic annotation, and pronounced geographic underrepresentation, particularly of Asian populations. Because most publicly available anellovirus genomes have been sampled from European and North American cohorts, the diversity circulating in other regions has been systematically missed, distorting estimates of global viral richness. To address this gap, the team integrated metagenomic sequencing data from 6,348 Chinese samples with all globally available ANV genomes, constructing an expanded phylogenomic resource that they call the HANVdb Resource.

The scale of the resulting expansion is striking. By harmonizing taxonomy across more than 23,000 accession-level genome records and applying a standardized species-delineation threshold based on ORF1 nucleotide identity, the researchers expanded the represented diversity of human-associated anelloviruses to 771 species-level taxa. Of these, 91 correspond to species formally recognized by the International Committee on Taxonomy of Viruses (ICTV), while a remarkable 680 represent provisional new species (PNS) that had never been catalogued before. That corresponds to an approximately eightfold increase in represented species-level diversity compared with previous reference frameworks, a jump driven largely by the inclusion of Chinese metagenomic data that captured lineages absent from Western-dominated databases.

With this expanded reference in hand, the team turned to the question of what an individual person actually carries. Profiling personal anellomes at species-level and lineage-level resolution revealed extraordinary within-host diversity. The richest individual profile in the analyzed cohorts contained 305 species-level taxa and 2,071 distinct lineages, meaning that a single person can simultaneously host hundreds of anellovirus species and thousands of genetic variants. This level of intra-host diversity rivals, and in many respects exceeds, what has been documented for bacterial communities of the gut microbiome, and it establishes the anellome as one of the most genetically heterogeneous viral communities known to colonize humans.

Beyond raw diversity, the study sought to determine whether the anellome has a stable ecological architecture. By integrating detection frequency, abundance, geographic representation, cross-cohort reproducibility and longitudinal persistence, the researchers identified recurrent “core” anellome components: species and lineages that appear consistently across individuals, cohorts and time points. Longitudinal analysis of publicly available datasets confirmed that these core lineages persist within individuals over years, behaving less like transient infections and more like stable residents of the personal virome. This finding supports the emerging view of anelloviruses as genuine commensals, viruses that establish chronic, largely asymptomatic carriage and whose presence may reflect, and even report on, the immunological state of their host.

That connection to immunity received direct support from the study’s clinical analyses. Several core lineages showed significant inverse associations with CD4 T-cell counts in HIV-infected individuals, meaning that as immune function declined, the abundance of these viral lineages rose. This pattern is consistent with the hypothesis that anellovirus replication is held in check by T-cell-mediated immune control, and it raises the possibility that anellome profiling could serve as a surrogate readout of immune competence. Such a biomarker would be attractive precisely because anelloviruses are so ubiquitous: unlike opportunistic pathogens, they are present in nearly everyone, providing a continuous signal that can be monitored through routine metagenomic sequencing of blood or other specimens.

The study also examined how the anellome is distributed across body compartments. By analyzing paired samples of peripheral blood mononuclear cells (PBMCs) and plasma from the same individuals, the researchers identified compartment-associated differences in diversity, composition and lineage enrichment. Certain lineages were preferentially associated with the cellular fraction, while others dominated the cell-free plasma fraction, indicating that anelloviruses are not passively circulating but instead occupy distinct ecological niches within the bloodstream. This compartmental organization adds a spatial dimension to anellome ecology and suggests that sampling choices, whether one sequences cells or plasma, can materially change the picture of viral diversity obtained.

Among the most technically intriguing findings concerns a specific clade of Betatorquevirus associated with TTMV::RARA, a viral-host gene fusion previously linked to disease. Within the new framework, this clade displayed higher conservation of the ORF2 protein, enrichment of RUNX1 transcription factor motifs, and a PBMC-biased distribution compared with background clades. These molecular signatures hint at mechanistic differences in how this lineage interacts with host cells, potentially including altered replication regulation or integration behavior. While the study stops short of establishing causation, the identification of such lineage-level features provides concrete, testable hypotheses for investigating viral integration-associated disease, an area of growing interest given that anellovirus sequences have been found integrated into tumor genomes in hematologic malignancies.

All of these results are packaged into a reusable analytical infrastructure. The HANVdb Resource includes a curated Human Anellome Reference Dataset v1.0 comprising 10,013 lineages, a standardized pipeline for profiling anellomes from metagenomic sequencing data, and a publicly accessible web interface for downloading reference sequences. The pipeline encompasses reference extraction and clustering, raw-read quality control, host read removal, lineage-level quantification and filtering of low-confidence detections, and the authors validated their assignments through competitive read-level cross-referencing against broad viral databases. Multidimensional scaling and self-organizing map projections of the ORF1 identity matrix provide a discretized map of global anellome sequence space, allowing any new sample to be positioned within the known diversity. The resource, funded by the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences and the National Natural Science Foundation of China, is released under open access terms to encourage adoption by other groups.

The broader significance of this work lies in reframing how scientists think about the viruses that live within us. Rather than viewing anelloviruses as a diffuse background of incidental infections, the study demonstrates that the human anellome is a structured commensal community, resolvable at species and lineage levels, with stable core members, compartment-specific organization and measurable relationships to host immunity. The eightfold expansion of catalogued diversity underscores how much remains undiscovered, particularly outside well-sampled Western populations, and the strong representation of Asian cohorts in this dataset begins to correct a longstanding geographic bias in virome research. As metagenomic sequencing becomes routine in clinical medicine, tools like the HANVdb Resource may transform anelloviruses from obscure commensals into practical indicators of immune health, and could ultimately clarify their role in the pathogenesis of hematologic disease. For now, the message is clear: the most familiar viruses in the human body are also among the least understood, and mapping them is only just beginning.

Subject of Research: Genomic diversity and ecological structure of the human anellovirus virome (anellome)

Article Title: Defining the genomic and ecological landscapes of the human anellome

Article References: Zhao, P., Chen, M., Kang, Y., Keng, J., Li, X., Feng, B., Sui, H., Dong, J., Sun, L., Jin, Q., Hu, Y., & Yang, F. (2026). Defining the genomic and ecological landscapes of the human anellome. Microbiome. https://doi.org/10.1186/s40168-026-02552-0

Image Credits: AI Generated

DOI: 10.1186/s40168-026-02552-0

Keywords: anellovirus, anellome, human virome, metagenomics, HANVdb, commensal viruses, Betatorquevirus, TTMV::RARA fusion, CD4 T-cell counts, PBMC, plasma, Microbiome journal

Head and neck squamous cell carcinoma, abbreviated HNSCC, is one of the most common cancers worldwide, arising from the flat cells that line the mucosal surfaces of the larynx, pharynx, oral cavity and related structures. Because these tumors develop in a region that is continuously bathed in saliva and colonized by hundreds of microbial species, researchers have long suspected that the oral microbiome might play an active role in the disease. The concept has gained traction under the name of the oncobiome: the idea that microorganisms within the tumor microenvironment are not passive bystanders but may influence how tumors form, how they respond to therapy, and ultimately how patients fare. The new study provides some of the most concrete evidence yet that this influence extends to survival itself.

The research was designed as a prospective study, meaning that patients were enrolled and sampled according to a predefined protocol rather than retrospectively selected from archived material. The cohort included 86 patients with laryngeal carcinoma and 38 with pharyngeal carcinoma, alongside the 66 healthy controls. Saliva was collected with informed consent under ethical approvals from the Hospital Universitario Central de Asturias and the regional ethics committee of the Principality of Asturias. The team then applied 16S rRNA gene sequencing, a technique that reads a specific genetic marker found in all bacteria, allowing researchers to identify which genera and species are present in each sample and in what relative proportions, without needing to culture the organisms in the laboratory.

The first major finding was that cancer patients and healthy controls carried clearly distinct microbial community profiles. Just as striking was the discovery of pronounced site-specific dysbiosis, meaning that the pattern of microbial imbalance differed depending on where in the upper aerodigestive tract the tumor had arisen. Pharyngeal tumors and laryngeal tumors were associated with different salivary bacterial landscapes, a detail that matters because most previous studies have treated head and neck cancer as a single entity. The anatomical context of the tumor, in other words, appears to shape the ecology of the mouth around it, and any biomarker derived from saliva would need to respect that context to be clinically useful.

Treatment itself also left a microbial fingerprint. The researchers compared microbiome composition before and after therapy and found that chemoradiotherapy, the combination of chemotherapy and radiation used in many HNSCC patients, induced a marked remodeling of the oncobiome. The most notable post-treatment change was an enrichment of Lactobacillus, a genus of lactic acid bacteria that is often abundant in altered oral environments. Whether this shift is a consequence of tissue damage, changes in saliva production and pH, or a direct selective effect of the treatment on bacterial growth remains an open question, but it demonstrates that the salivary microbiome is a dynamic system that responds to clinical intervention rather than a fixed attribute of the patient.

The centerpiece of the study, however, is a ten-bacteria salivary signature associated with poorer survival outcomes. Using statistical models, the team identified a specific combination of bacterial taxa whose collective abundance in saliva was linked to worse disease-specific survival, worse overall survival, and worse disease-free survival, the three standard endpoints used in oncology. The strength of the association was remarkable. In multivariable Cox regression analysis, which adjusts for established clinicopathological variables such as tumor stage and site, the ten-bacterial signature remained independently associated with poor prognosis, with a hazard ratio of 6.215 for disease-specific survival, 5.417 for overall survival, and 6.842 for disease-free survival, all with p values below 0.001. Hazard ratios of this magnitude indicate that patients carrying the adverse signature faced a roughly five- to seven-fold higher risk of death or recurrence compared with patients whose salivary microbiome lacked it.

Beyond the unified signature, the study uncovered tumor site-specific prognostic taxa, bacteria whose association with survival depended on where the tumor was located. In pharyngeal carcinomas, the presence of putative species belonging to the genera Prevotella, Porphyromonas and Fusobacterium correlated significantly with improved disease-specific, overall and disease-free survival. This is a counterintuitive result, because Fusobacterium in particular has been implicated in promoting colorectal tumors, yet here its presence in the saliva of pharyngeal cancer patients was associated with a favorable outcome. In laryngeal carcinomas, a different set of organisms told a different story: putative Stomatobaculum longum and Dialister were associated with favorable survival outcomes. The authors interpret these findings as support for the concept of an anatomically contextualized oncobiome, in which the prognostic meaning of a given bacterium cannot be separated from the anatomical site of the tumor it accompanies.

Technically, the study relied on ANCOM-BC, a modern differential abundance method that corrects for the compositional nature of sequencing data, to compare microbial communities between groups. Prognostic associations were then tested with univariable and multivariable Cox proportional hazards models, the standard framework for survival analysis in medicine, supplemented by Kaplan-Meier style survival analyses. The word putative in the species-level assignments reflects a limitation of 16S rRNA sequencing: because the method reads only a marker gene rather than whole genomes, it can often identify a bacterium only to the genus level, with species-level calls made by inference. Higher-resolution approaches such as shotgun metagenomic sequencing would be needed to confirm the exact species and strains involved, and the authors are explicit that validation in independent cohorts is required before any clinical implementation.

Even with those caveats, the implications are considerable. Current prognostic assessment in HNSCC rests largely on tumor staging, grading, anatomical site and a handful of molecular markers, all of which are typically obtained through invasive biopsies and imaging. A salivary microbiome signature offers something different: a non-invasive, dynamic biomarker that can in principle be sampled repeatedly over time, before treatment, during follow-up, and at the first suspicion of recurrence. Because saliva collection is cheap, painless and acceptable to patients, a validated microbial risk score could be integrated into routine surveillance, helping clinicians decide which patients need intensified follow-up imaging or adjuvant therapy and which can be monitored less aggressively. It could also, in the longer term, open the door to microbiome-targeted interventions aimed at shifting the oral ecology toward a more favorable state.

The study was conducted by researchers from the Instituto de Investigación Sanitaria del Principado de Asturias in Oviedo, the University of Oviedo, the Spanish Biomedical Research Network in Cancer, the Dairy Research Institute of Asturias, the FISABIO Foundation in Valencia, and Dartmouth’s Geisel School of Medicine, with funding from the Instituto de Salud Carlos III and co-financing from the European Union and regional institutions. The work was published open access on 9 October 2026 in Microbiome under DOI 10.1186/s40168-026-02548-w. For now, the ten-bacteria signature remains a research finding rather than a bedside test, and the authors caution that larger, independent and higher-resolution studies must confirm the result. But the message is clear: the bacteria in a patient’s saliva are not just spectators to head and neck cancer. They form a readable, quantifiable signature of the disease’s trajectory, and learning to read it may reshape how survival risk is assessed in one of the world’s most challenging cancers.

Subject of Research: Salivary microbiome signatures as prognostic biomarkers for survival and recurrence in head and neck squamous cell carcinoma

Article Title: Salivary prognostic bacterial signatures associated with survival outcomes and recurrence risk in head and neck squamous cell carcinoma

Article References: Granda-Díaz, R., Molinero, N., Sánchez-Canteli, M., Álvarez-Teijeiro, S., Mira, A., Allonca, E., Quesada, V., Margolles, A., Martínez-Camblor, P., Martín-Guillermo, E., Delgado, S., Rodrigo, J. P., & García-Pedrero, J. M. (2026). Salivary prognostic bacterial signatures associated with survival outcomes and recurrence risk in head and neck squamous cell carcinoma. Microbiome. https://doi.org/10.1186/s40168-026-02548-w

Image Credits: AI Generated

DOI: 10.1186/s40168-026-02548-w

Keywords: salivary microbiome, head and neck squamous cell carcinoma, oncobiome, 16S rRNA sequencing, prognostic biomarkers, dysbiosis, Lactobacillus, Fusobacterium, chemoradiotherapy, survival analysis, recurrence risk, Microbiome journal

The research, led by Giacomo Carta, Feng Xian, Daniel Malzl, and senior authors Manuela Schmidt and David Gómez-Varela at the University of Vienna, together with colleagues at CeMM and the Ludwig Boltzmann Institute for Network Medicine, applied metaproteomics to fecal samples collected at seven postnatal time points, beginning at day 10 and extending through weaning into early adulthood at day 48. Metaproteomics is a technique that directly measures the proteins being produced by the microorganisms living in a sample, rather than merely cataloguing which microbial genes are present. Because proteins are the functional workhorses of cells, this approach reveals what the gut ecosystem is actually doing at each moment, not just who lives there.

The experimental design was deliberately rigorous. The team studied pups from two contemporaneously raised C57BL/6 cohorts that differed only in maternal origin: one group came from a long-established local colony, while the other was born to newly purchased pregnant females from the same vendor. All animals were housed identically and ate the same food. By analyzing both cohorts and accounting for time, cohort, and sex effects, the researchers could separate genuine developmental trajectories from the influence of maternal background and sex, a distinction that is often blurred in single-cohort studies.

What emerged was a clear picture of taxonomic succession. In the earliest days of life, the gut is dominated by facultative anaerobes, microorganisms that can survive both with and without oxygen. This makes ecological sense: a newborn intestine is not yet fully anoxic, and these hardy pioneers can tolerate its residual oxygen. After weaning, the community shifted decisively toward obligate anaerobes, strict oxygen-hating bacteria that thrive in the mature, oxygen-depleted gut. Alongside this turnover, species richness and functional complexity increased steadily, and the patterns held across both cohorts and both sexes, suggesting a robust developmental program rather than a stochastic accident.

One of the study’s most striking findings concerns functional redundancy. As the community matured, different microbial species increasingly came to perform overlapping functions, so that multiple organisms could carry out the same metabolic task. This redundancy converged by postnatal day 34 and then remained stable into early adulthood. Ecologically, redundancy is a hallmark of a resilient ecosystem: if one species is lost, others can fill its functional role. The finding implies that the young gut actively builds in backups as it matures, a process that may underpin the stability of the adult microbiome and its resistance to perturbation.

Clustering of proteins by KEGG pathway categories, a standard reference system for grouping genes and proteins into metabolic and cellular functions, revealed a dynamic interplay between change and constancy. The representation of metabolic pathways shifted substantially as the animals grew, reflecting the changing nutritional landscape of the intestine, yet a core set of functions was maintained throughout development. In other words, the ecosystem remodels its periphery while preserving its essential machinery, much as a city renovates its neighborhoods while keeping power plants and water systems running.

Perhaps the most technically impressive aspect of the work is the direct detection of low-abundant dietary proteins in the fecal samples. Because mass spectrometry can identify proteins by their peptide sequences, the researchers could literally see what the animals had been eating. Milk proteins appeared only before weaning, while components of solid food increasingly predominated as the pups matured. This provides molecular-level evidence that dietary transitions coincide precisely with microbial maturation, linking the nutritional switch at weaning to the ecological handover from facultative to obligate anaerobes and the rise in functional complexity.

The maternal origin effect was equally consequential. Despite identical housing, diet, and genetic background, the two cohorts showed significantly different microbial engraftment trajectories, producing cohort-specific taxonomic and functional profiles. This finding carries a sobering message for the vast field of mouse-based biomedical research: where the mothers came from, and by extension which microbes the pups inherited at birth, can leave measurable imprints on the gut ecosystem for weeks. Studies that fail to report or control for maternal and colony origin may inadvertently introduce variability that confounds their results, a point the authors emphasize as relevant to experimental design and reproducibility.

The host side of the story proved to be just as dynamic. By profiling the intestinal proteome of the developing animals, the researchers found that host maturation mirrored microbial succession. As the microbiome shifted, the gut itself remodeled its protein landscape, with coordinated changes in metabolic pathways, absorptive functions, regulatory mechanisms, and effector molecules. Notably, this included antimicrobial peptides, the host’s own chemical weapons for shaping microbial communities, and carbohydrate-modifying enzymes, which process the complex sugars that become abundant with solid food. The picture is one of mutual choreography: the microbes and the intestine appear to mature in lockstep, each influencing the other’s trajectory.

By integrating microbial taxonomy, microbial function, dietary composition, and host biology within a single longitudinal framework, the study offers what its authors describe as a comprehensive reference for understanding how the murine gut ecosystem matures during early life. For microbiome researchers, it provides a benchmark against which developmental dynamics can be interpreted. For the broader experimental community, it delivers a practical warning about maternal origin as a hidden variable. And for anyone interested in the origins of the human microbiome, it demonstrates that the tools now exist to watch an entire ecosystem, and its host, grow up together, protein by protein, day by day.

Subject of Research: Longitudinal metaproteomic characterization of host–microbiome–diet interactions during early-life gut development in mice

Article Title: Integrative characterization of host–microbiome-diet axes during early-life development of the murine gut

Article References: Giacomo, C., Xian, F., Malzl, D., Schmidt, M., & Gómez-Varela, D. (2026). Integrative characterization of host–microbiome-diet axes during early-life development of the murine gut. Microbiome. https://doi.org/10.1186/s40168-026-02541-3

Image Credits: AI Generated

DOI: 10.1186/s40168-026-02541-3

Keywords: gut microbiome, metaproteomics, mouse development, host-microbiome interactions, diet, weaning, microbial succession, functional redundancy, maternal origin, C57BL/6, intestinal proteome, Microbiome journal

The research, led by Lingming Kong, Fengyu Shi, Hongru Kong and Haonan Xie, with Gang Chen as senior author, was carried out by teams at Wenzhou Medical University and collaborating institutions in China and the United States. The investigators focused on elderly-onset acute pancreatitis, abbreviated EOAP, and asked a deceptively simple question: does the gut microbiome of an aged organism process food differently in ways that make pancreatic injury worse? Their answer, built from mouse experiments and human clinical samples, is a carefully documented yes. The work identifies a specific microbial group, a specific metabolite and a specific cellular mechanism that together appear to convert an age-related shift in gut ecology into genuine pancreatic damage.

The starting point was a comparative analysis of metabolites. When the researchers profiled the metabolic output of the gut in aged mice and in elderly patients suffering from acute pancreatitis, two molecules stood out: phenaceturic acid, known as PAC, and phenylacetylglutamine, known as PG. Both are downstream products of phenylalanine metabolism. Phenylalanine is an essential aromatic amino acid that humans obtain from dietary protein, and gut bacteria routinely ferment it into a family of phenyl-containing compounds that are absorbed into the bloodstream and eventually excreted. In the aged animals and the elderly patients, the levels of these two phenylalanine-derived metabolites were markedly elevated compared with younger counterparts, suggesting that aging fundamentally rewires how the gut handles this amino acid.

Who was producing the extra metabolites? Metagenomic analysis of the gut communities pointed to a familiar and somewhat notorious culprit: bacteria belonging to the Escherichia-Shigella group. This cluster, which includes organisms closely related to Escherichia coli and Shigella species, was significantly more abundant in the aged mice and elderly patients. The correlation between Escherichia-Shigella expansion and elevated PAC and PG levels provided the first mechanistic thread: an age-associated bloom of particular bacteria appears to drive increased microbial processing of phenylalanine, flooding the host with metabolites that a younger gut produces in smaller quantities.

Correlation alone, however, is never enough to establish causation, and the team moved decisively to test it. Using fecal microbiota transplantation, they transferred gut communities from aged donor mice into young recipient mice. The young animals, which normally tolerate experimental pancreatic injury with a moderate inflammatory response, developed a strikingly aggravated phenotype after receiving the aged microbiota. Their pancreatitis became more severe, mirroring the pattern seen in naturally aged animals. This transfer experiment is conceptually powerful because it isolates the microbiome as a sufficient carrier of the age-related risk: the recipients’ own genomes and chronological age were unchanged, yet their disease outcome was transformed by the microbial community they received.

With the microbial contribution established, the researchers turned to the cellular level to understand how phenaceturic acid actually damages the pancreas. The pancreas’s exocrine tissue is built from acinar cells, specialized factories that produce and secrete digestive enzymes. These cells are packed with mitochondria, the organelles that generate the energy required for massive protein synthesis and export. The team found that PAC compromises mitochondrial integrity in these acinar cells. Damaged mitochondria are not merely idle; they leak reactive oxygen species, release pro-death signaling molecules and trigger quality-control responses that can themselves become destructive when overwhelmed.

One of those quality-control responses, mitophagy, sits at the center of the proposed mechanism. Mitophagy is the cellular process by which defective mitochondria are selectively engulfed and degraded, normally a protective housekeeping function that keeps the mitochondrial network healthy. The study’s findings indicate that in the context of EOAP, PAC-driven mitochondrial damage pushes mitophagy into overdrive, and rather than rescuing the cells, this excessive mitophagy coincides with enhanced cell death. The acinar cells undergo apoptosis, the programmed death pathway, at elevated rates. Widespread acinar cell death is a hallmark of severe pancreatitis because dying cells release their contents, including digestive enzymes and damage-associated molecular patterns, which amplify the inflammatory cascade and recruit further immune activation.

The chain of evidence therefore reads as follows: aging reshapes the gut microbiome, allowing Escherichia-Shigella to expand; these bacteria convert more dietary phenylalanine into phenaceturic acid and phenylacetylglutamine; elevated PAC circulates to the pancreas, where it undermines mitochondrial integrity in acinar cells; runaway mitophagy and apoptosis follow; and the resulting cell death intensifies inflammation, making the overall disease more severe. Each link in this chain was supported by the study’s combination of human sample analysis, mouse modeling, microbial transplantation and mechanistic cell biology, forming one of the more complete causal narratives in the microbiome-pancreatitis literature.

The clinical implications are considerable. Acute pancreatitis in the elderly is a growing burden as populations worldwide age, and current treatment remains largely supportive, with no approved drugs that specifically target the mechanisms of disease severity. If the findings hold up in further studies, they suggest several concrete intervention points. Microbial phenylalanine metabolism could be modulated with dietary strategies that alter protein intake or amino acid availability. The offending bacterial groups could be suppressed with targeted antimicrobials or outcompeted through microbiome-directed therapies. The metabolites themselves, PAC and PG, could serve as biomarkers, allowing clinicians to identify elderly patients at risk of severe disease before the inflammatory storm fully develops. And the downstream mitochondrial and apoptotic pathways offer pharmacological targets for drugs that stabilize mitochondrial function or restrain excessive cell death.

As with any translational study, important questions remain. The work was conducted in mouse models and human cohort samples, and the precise dose-response relationship between circulating PAC and pancreatic injury in humans will need prospective validation. It is also not yet clear whether reducing phenylalanine-derived metabolites after pancreatitis has already begun can improve outcomes, or whether the intervention window lies earlier, in maintaining a healthier microbiome throughout aging. What the study undeniably establishes is that the age-related severity of acute pancreatitis is not written solely in the pancreas or the immune system, but is partly manufactured in the gut by microbial chemistry. That reframing — treating a metabolic product of our resident bacteria as a driver of organ failure — is likely to resonate well beyond pancreatology, and it adds pancreatic disease to the expanding list of conditions, from neurodegeneration to cardiovascular disease, in which microbial metabolites of dietary amino acids are emerging as unexpected culprits.

Subject of Research: The role of gut microbiota-derived phenylalanine metabolites in exacerbating elderly-onset acute pancreatitis through mitochondrial dysfunction and cell death

Article Title: Gut microbiota-derived phenylalanine metabolites exacerbate elderly-onset acute pancreatitis by promoting mitophagy and enhancing cell death

Article References: Kong, L., Shi, F., Kong, H., Xie, H., Pan, Z., Liu, Z., Yu, D., Chen, W., Sun, H., Jin, Y., Wang, J., Ergashev, A., Li, T., Wang, Y., Zhang, J.-S., Fernandez-Zapico, M. E., Zhang, C., & Chen, G. (2026). Gut microbiota-derived phenylalanine metabolites exacerbate elderly-onset acute pancreatitis by promoting mitophagy and enhancing cell death. Microbiome. https://doi.org/10.1186/s40168-026-02518-2

Image Credits: AI Generated

DOI: 10.1186/s40168-026-02518-2

Keywords: elderly-onset acute pancreatitis, gut microbiota, phenylalanine metabolism, phenaceturic acid, phenylacetylglutamine, Escherichia-Shigella, mitophagy, apoptosis, mitochondrial dysfunction, acinar cells, fecal microbiota transplantation, Microbiome journal

The core microbiome concept rests on a simple intuition. Within any habitat type, whether a host species, a soil ecosystem, or an ocean region, some members of the microbial community appear again and again across samples, while others come and go. The recurring members are presumed to matter most: they may perform essential functions for the host, stabilize community dynamics, or define the characteristic identity of that environment. In practice, researchers have typically identified the core by counting how often particular taxa occur across samples and keeping those that pass a predefined threshold of presence or abundance. Over the past decade, a rich toolbox of occurrence-based and abundance-based measures has grown around this idea, allowing scientists to quantify which microbes constitute the stable backbone of everything from human guts to coral reefs.

What has been missing, the Clemson authors argue, is evolution. Most existing core microbiome measures treat taxa as isolated labels, blind to the branching history that connects them. That blindness creates two well-known problems. The first is inconsistency across taxonomic rank: a microbe that appears in ninety percent of samples at the species level may be split into several lineages that each fail the threshold, or lumped into a genus that trivially passes it, so conclusions flip depending on whether the analyst works with operational taxonomic units, species, genera, or families. The second is sensitivity to strain variation: closely related strains within a single species can differ enormously in their presence across samples, causing non-phylogenetic measures to register dramatic turnover where, evolutionarily speaking, almost nothing has changed.

Bewick and Camper’s solution begins with a new object they call the core community phylogeny. Rather than selecting individual taxa that pass an occurrence threshold, the approach works directly on the evolutionary tree that describes the relationships among all microbes detected across a set of samples from a single habitat type. Branches of that tree are retained if they are present in multiple samples, in effect asking not whether a particular named species is shared, but whether a particular slice of evolutionary history is shared. The result is a pruned phylogeny whose branches represent the conserved evolutionary fabric of the community, the portion of the microbial tree of life that reliably shows up in that habitat, regardless of how individual strains or species shuffle beneath it.

From this core community phylogeny, the authors derive a family of phylogenetic metrics that mirror the classic questions microbiome ecologists already ask, but answer them in evolutionary currency. The first describes the phylogenetic diversity of a core microbiome within a single habitat type, capturing how much of the tree of life the conserved branches span. The second quantifies phylogenetic turnover between core microbiomes drawn from two different habitat types, measuring how much of the conserved evolutionary history is replaced when moving from one environment to another. The third measures shared phylogenetic diversity across core microbiomes from two or more habitat types, identifying the deep, evolutionarily conserved component that persists across otherwise distinct communities. Together, these measures extend the familiar logic of phylogenetic beta diversity into the specific context of core microbiome analysis.

The technical payoff is consistency. Because the metrics are computed on branches of a phylogeny rather than on labels at a chosen rank, their values remain stable whether the underlying community data are summarized at fine or coarse taxonomic resolution. When the same microbial community is described at the level of strains, species, or higher taxa, the core community phylogeny and its associated measures converge on the same answer, because the evolutionary information is preserved at every level. Likewise, strain-level variation, which can dominate and distort occurrence-based core definitions, is absorbed naturally into the tree: closely related strains contribute overlapping branches, so their idiosyncratic patterns of presence and absence no longer masquerade as wholesale community change. The authors report that, compared with non-phylogenetic metrics, their framework shows greater consistency across taxonomic rank and phylogenetic level, along with reduced sensitivity to strain variation.

That robustness matters far beyond statistical tidiness. Meta-analyses in microbiome science are frequently hampered by the fact that different studies process their sequencing data at different resolutions, making it hazardous to compare core microbiome findings across papers, hosts, or ecosystems. A framework that integrates seamlessly across taxonomic rank and phylogenetic level allows researchers to pool and compare results without first forcing every dataset into an identical labeling scheme. It also opens the door to genuinely novel biological questions. Instead of asking which named taxa form the core of a habitat, scientists can ask which lineages, and which evolutionary functions embedded in the tree, are conserved across hosts or environments, and how deep in the tree that conservation runs. A core defined by deep branches suggests ancient, possibly co-evolved associations; a core confined to shallow branches suggests recent ecological filtering of whatever lineages happen to be available locally.

The study did not emerge from simulations alone. The acknowledgements and supplementary materials reveal an empirical foundation built from fieldwork in New Mexico, where the authors, with support from National Science Foundation awards and Clemson University programs, assembled gut and skin microbiome samples from lizards, along with the read counts, taxonomy assignments, microbial phylogenies, and metadata that accompany them. Lizards, with their partitioned gut and skin habitats on the same individual animals, provide a natural test bed for contrasting core microbiomes across habitat types and for demonstrating how phylogenetic turnover and shared diversity behave when the same host carries distinct microbial communities in different body regions. A simplified worked example accompanying the paper walks readers through the construction of core community phylogenies and the calculation of the associated metrics step by step, lowering the barrier for laboratories that want to adopt the approach.

The implications ripple outward across applied microbiome research. In human health, core microbiome analyses inform debates about which microbes are essential partners rather than transient passengers, and inconsistent rank-dependent results have complicated efforts to define a healthy reference core. In agriculture, core definitions guide the design of synthetic microbial communities and probiotic formulations for crops and livestock, where strain-level variability among commercial inoculants has been a persistent headache. In conservation and ecosystem management, comparing cores across disturbed and intact habitats depends on measures that do not change their verdict when taxonomic pipelines change. A phylogenetically grounded core concept offers each of these fields a common, evolution-aware yardstick, one in which the currency is conserved branch length rather than mutable species lists.

None of this means the era of taxon-based core microbiome analysis is over; named taxa remain indispensable for communication, culturing, and mechanistic follow-up, and phylogenetic measures complement rather than replace occurrence and abundance metrics. But the study marks a conceptual maturation for the field, aligning the core microbiome with the tree-thinking that already underpins much of ecology and evolutionary biology. As microbiome datasets continue to explode in size and diversity, tools that deliver stable answers across resolutions, and that translate the question of what is shared into the question of what evolutionary history is shared, are likely to spread quickly through the community. The core microbiome, long a moving target, may finally have a measure that holds still.

Subject of Research: Phylogenetic methods for measuring and comparing the core microbiome across habitat types

Article Title: Phylogenetic measures of the core microbiome

Article References: Bewick, S. A., & Camper, B. T. (2026). Phylogenetic measures of the core microbiome. Microbiome. https://doi.org/10.1186/s40168-026-02520-8

Image Credits: AI Generated

DOI: 10.1186/s40168-026-02520-8

Keywords: core microbiome, microbial ecology, phylogenetics, community phylogeny, phylogenetic diversity, beta diversity, taxonomic rank, strain variation, microbiome metrics, lizard microbiome, evolutionary conservation, Microbiome journal