The article, published in Frontiers in Oncology, is a commentary rather than a new clinical study or case series. Its authors, Huizhen Du, Congcong Geng, Na Zhu, Zhao Li, Yalu Liu, Chunyan Liu, Jing Niu, Qian Wang and Hongwei Ren, introduce no additional patient data. Instead, they reassess the diagnostic evidence in a case report by Liu, Gao, Du, Ji and Li. The commentators state that the molecular association between the reported disease and FGFR1 rearrangement was already known and was not presented as a new observation.

The original report described two distinct abnormal populations in bone marrow flow cytometry. One accounted for 17.54% of cells and was identified as abnormal mast cells. A second population comprised 63.5% of nucleated cells, expressed strong CD33, weak CD11b and CD2, and lacked CD13, CD34, CD117 and CD203c. Because of this unusual phenotype, flow cytometry could not confidently establish the cellular origin of the larger population.

Bone marrow biopsy immunohistochemistry produced a different immunophenotypic pattern: the abnormal cells were reported to express CD117, CD25, CD2 and tryptase. The commentary treats this cross-platform discordance as the central diagnostic issue rather than as proof that the flow-cytometric population absolutely lacked CD117. On retrospective visual inspection of the published flow-cytometry plot, the authors say it may not be possible to distinguish complete CD117 negativity from very dim expression. The original case report also did not describe a distinct dual, dim-and-strong CD117 staining pattern on immunohistochemistry.

The authors emphasize that CD117 is useful but should not be interpreted alone. Citing a review of flow-cytometric pitfalls, they note that no single antigen is completely specific and that mast-cell identification requires a multiparameter approach incorporating marker combinations, gating strategy and awareness of interfering populations. In a case with an unusual immature phenotype, reported absence or very dim expression of CD117 or CD203c in flow cytometry should therefore prompt reconciliation with morphology, histology and complementary immunophenotyping before mast-cell differentiation is excluded. CD68 staining in the original report is not treated by the commentary as independent proof of mast-cell lineage; the interpretation instead relies on morphology and the mast-cell-associated findings, including tryptase.

FGFR1 rearrangement raises a separate classification issue. Current World Health Organization and International Consensus Classification frameworks recognize FGFR1-rearranged disease within the genetically defined spectrum of myeloid/lymphoid neoplasms with tyrosine-kinase gene fusions. These neoplasms may have heterogeneous myeloid and/or lymphoid manifestations, and eosinophilia, although present in many cases, is not obligatory. The original case included leukocytosis, splenomegaly and mildly FDG-avid enlarged hepatotactic and retroperitoneal lymph nodes. The main article did not report a lymph-node biopsy or provide an eosinophil count, leaving those aspects incompletely characterized.

The reported marrow morphology showed no dyserythropoiesis, ring sideroblasts, multinuclearity or myeloid blasts, and the original report used those observations to exclude an associated hematologic neoplasm. The commentary argues that these findings do not settle the classification question in the presence of an FGFR1 rearrangement. The complex karyotype included dic(8;11)(p12;q12); involvement of 8p11–12 is cytogenetically compatible with the FGFR1 rearrangement later demonstrated by break-apart fluorescence in situ hybridization, although the specific fusion partner was not established. The published data consequently cannot distinguish definitively between primary mast-cell leukemia carrying an FGFR1 rearrangement and an FGFR1-rearranged myeloid/lymphoid neoplasm with prominent mast-cell differentiation.

The molecular interpretation also has bounded limits. Illumina high-throughput sequencing reportedly found a wild-type KIT sequence as well as SETD2 and GNB1 mutations, while the FGFR1 rearrangement was demonstrated by FISH. The commentary says the report does not provide enough assay-level information to verify coverage of individual non-D816V KIT variants. Absence of the D816V mutation alone therefore should not be interpreted as excluding all activating KIT mutations, including reported non-D816V variants such as K509I, N819Y and I817V. The report also did not identify the CD117 antibody clone used for immunohistochemistry, confirm the flow-cytometric CD117 assessment with isotype controls, or report a separate RNA assay defining the FGFR1 fusion transcript.

Clonal identity between the phenotypically different cell populations also remains unestablished because the population reported as CD117-negative was not separately sorted for molecular analysis. The commentary’s conclusion is therefore cautious: when morphology, tissue immunophenotyping, flow cytometry and a defining genomic abnormality appear discordant, lineage assignment and disease classification require integrated review rather than reliance on CD117 or any single platform alone. Its practical contribution is to delineate what the published case establishes, what remains unresolved and which distinctions cannot be verified from the available assay and clinical information.

Subject of Research: Diagnostic and classification ambiguity in a reported FGFR1-rearranged acute mast cell leukemia case

Article Title: Commentary: Case Report: Experience of a rare case of primary acute mast cell leukemia with FGFR1 gene rearrangement

Article References: Du, H., Geng, C., Zhu, N., Li, Z., Liu, Y., Liu, C., Niu, J., Wang, Q., & Ren, H. (2026). Commentary: Case Report: Experience of a rare case of primary acute mast cell leukemia with FGFR1 gene rearrangement. Frontiers in Oncology, 16, Article 2001012. https://doi.org/10.3389/fonc.2026.2001012

Image Credits: AI Generated

DOI: 10.3389/fonc.2026.2001012

Keywords: FGFR1 rearrangement, acute mast cell leukemia, flow cytometry, CD117, immunohistochemistry, myeloid/lymphoid neoplasm, mast-cell diagnosis, case report commentary, molecular classification, Commentary, Case, Report

The study developed three multicolor panels for peripheral blood and selected solid-tissue samples, combining markers including CD45, MIL-4, panT, CD1b3, CD14, CD4 and CD8, with intracellular CD79α used to confirm B-cell identity. Analysis was performed on a BD LSRFortessa flow cytometer with BD FACSDiva software, followed by data analysis in FlowJo. The investigators used forward- and side-scatter characteristics together with fluorescence and viability information to distinguish leukocyte populations. A fluorescence-minus-one control in which the panT primary antibody was omitted was retained for routine work because the MsGp7 panT antibody produced a relatively low staining index, while an isotype control supported interpretation of intracellular CD79α staining.

Technical gating was central to the approach. In blood, CD45 was not essential, whereas it helped establish the total leukocyte compartment in solid tissues. The MIL-4-containing panel separated granulocytes and monocytes from lymphocytes and allowed neutrophils and eosinophils to be distinguished largely by side-scatter intensity. Eosinophils were provisionally identified as MIL-4-positive, high-scatter cells, an assignment supported by the larger, more abundant cytoplasmic granules visible on blood smears. Monocytes were identified as MIL-4-positive and CD14-positive cells, while the lymphocyte gate was defined as MIL-4-negative cells with lymphoid scatter characteristics. Because the panels were not always used together, CD4 and CD8 expression was interpreted within the gated lymphocyte fraction rather than across the entire leukocyte population.

Several cross-reactive reagents made the protocol implementable without custom antibody conjugation. These included guinea pig-specific anti-CD45 and anti-CD1b3 antibodies, an anti-pig CD11R1/MIL-4 reagent that also recognized guinea pig cells, cross-reactive anti-human CD14 and CD79α antibodies, and guinea pig-specific CD4 and CD8 antibodies. The MsGp7 panT antibody also replaced a previously used CT5 clone that was no longer commercially available. B-cell identification nevertheless required caution because CD1b3 was not exclusive to B lymphocytes and was also expressed by monocytes. CD14 or MIL-4 was therefore needed to exclude monocytes, and intracellular CD79α provided additional confirmation of the B-cell gate.

In 13 clinically healthy client-owned guinea pigs aged 2–3 years, both routine hematology and flow cytometry showed a lymphocyte-dominant peripheral blood profile. The median total white blood cell count was 10.9 × 10^9 cells per liter, with a range of 6.8–13.8 × 10^9 per liter. By flow cytometry, lymphocytes represented a median 62.5% of viable leukocytes, compared with 8.0% neutrophils, 8.5% eosinophils and 3.0% monocytes. Routine hematology produced broadly similar results: lymphocytes accounted for a median 67.8%, neutrophils 10.5%, eosinophils 5.3% and monocytes 2.3%. These observations establish baseline distributions for the particular client-owned crossbred cohort, not universal reference intervals for every guinea-pig population.

Flow cytometry further showed that T cells predominated within the healthy lymphocyte compartment, making up a median 78.9% of lymphocytes, while B cells accounted for 6.3%. The largest defined T-cell subset was CD4-negative, CD8-positive cells, which represented a median 50.7% of T cells. A further population lacking panT, CD1b3 and CD14 markers made up a median 5.0% of gated lymphoid cells; it was heterogeneous and may include Kurloff cells, although the study did not characterize it further. Comparisons with an independent experimental cohort found no significant difference in T/B lymphocyte ratios among guinea pigs aged 2 months, 9 months and 2–3 years: the respective medians were 15.3, 9.7 and 9.1, with a Kruskal–Wallis p-value of 0.2611.

The nine clinical animals entered the study because they had generalized peripheral lymphadenopathy, a palpable cervical mass considered consistent with lymphoid enlargement, leukocytosis driven mainly by lymphocytes, or combinations of these findings. Histopathology identified five cases of high-grade lymphoma, two thyroid gland adenocarcinomas, one fibrolipoma and one lymphadenitis. All five lymphomas occurred in animals with marked B-cell-predominant lymphocytosis, ranging from 62.8% to 95.3% of circulating lymphocytes, and low T/B ratios of 0.006 to 0.432. The five lymphoma cases had a mean age of 3.7 years and included three females and two males. By contrast, the four cases without histological evidence of lymphoid neoplasia lacked a uniform B-cell-predominant pattern, showing either T-cell predominance or a mixed lymphocyte population.

A detailed example illustrated how blood and tissue findings could be integrated. A 2.5-year-old female guinea pig presented with apathy, anorexia, generalized lymphadenopathy and a white blood cell count of 126.5 × 10^9 per liter. Flow cytometry found that 86.8% of viable blood leukocytes were lymphocytes, of which 86.2% were B cells and 11.0% were T cells, producing a T/B ratio of 0.13. The submandibular lymph node contained 96.8% B cells and 1.9% T cells, while the mesenteric lymph node and spleen each contained 91.8% B cells. Histopathology showed a monomorphic population with cellular atypia and mitotic figures, consistent with high-grade lymphoma, and PAX5 immunohistochemistry supported B-cell lineage. The marked blood lymphocytosis meant that lymphoma with peripheral blood involvement and primary B-cell leukemia both remained possible diagnoses.

The results demonstrate the panel’s potential as a clinical adjunct, but the evidence comes from a deliberately small and selected series. Tissue flow cytometry was performed in only three of the nine clinical cases, and the experimental age comparison used a separate untreated cohort. Peripheral blood may not represent the full cellular composition of an affected lymph node, while the absence of bone-marrow examination prevented definitive separation of lymphoma with a leukemic phase from primary leukemia. Histopathology remained necessary to establish the nature of the lesion, and the study did not establish prognostic thresholds, treatment responses or population-wide reference intervals. Larger studies incorporating paired blood, marrow and tissue samples would be needed to validate those applications, but the panels provide a practical and reproducible starting point for immunophenotyping guinea pig leukocytes.

Subject of Research: Flow-cytometric immunophenotyping of guinea pig leukocytes and lymphoid neoplasia

Article Title: A practical flow cytometric approach to leukocyte immunophenotyping in guinea pigs and its potential applications in lymphoid neoplasia

Article References: Štěpánová, H., Jeklová, E., Škorič, M., Jarošová, R., & Jekl, V. (2026). A practical flow cytometric approach to leukocyte immunophenotyping in guinea pigs and its potential applications in lymphoid neoplasia. Frontiers in Veterinary Science, 13, Article 1926791. https://doi.org/10.3389/fvets.2026.1926791

Image Credits: AI Generated

DOI: 10.3389/fvets.2026.1926791

Keywords: guinea pigs, flow cytometry, leukocyte immunophenotyping, B-cell lymphoma, lymphocytosis, veterinary diagnostics, CD79α, lymphoid neoplasia, practical, flow, cytometric, approach

The researchers collected F. rothmaleri during the flowering seasons of 2022 and 2023 from Montemayor del Río, Candelario and El Cabaco, three sites separated by approximately 20–50 kilometres and mountain ranges. Between 20 and 35 plants were examined per site, with individuals sampled at least three metres apart to reduce the chance of collecting rhizomatous clones. Morpho-anatomical examination identified the plants as F. rothmaleri, including a characteristic V-shaped leaf cross-section with square ribs and a non-scalloped abaxial surface. Flow cytometry of leaf tissue and counts of metaphase chromosomes from root-tip meristems confirmed the presence of tetraploid plants with 2n = 28, hexaploids with 2n = 42 and octoploids with 2n = 56. Their nuclear DNA contents were estimated as 7.54 ± 0.21 pg/2C, 12.81 ± 0.16 pg/2C and 15.58 ± 0.28 pg/2C, respectively.

The three cytotypes did not have identical geographic distributions. Montemayor del Río contained only tetraploids, El Cabaco contained only hexaploids, and Candelario held both tetraploid and octoploid individuals. Tetraploids from the two sites did not differ significantly in genome size, indicating that the apparent cytotype difference was not simply a geographic effect in the measurements. The authors also noted that the high-polyploid F. rothmaleri populations did not display the strong monoploid-genome reduction reported in some members of the Aulaxyper lineage. These features make the locality arrangement useful because the same host species and apparently the same fungal strain occur in distinct cytological contexts, including tetraploids and octoploids at one site.

Endophyte presence was detected independently by aniline blue staining of aerial tissues and by culturing disinfected stem or tiller material on potato dextrose agar. The two methods agreed for every tested plant. Infection was common at all localities, reaching 77.1% at Montemayor del Río, 82.4% at Candelario and 90.9% at El Cabaco. Rates were also similar among cytotypes: 81.5% for pooled tetraploids, 90.9% for hexaploids and 80.0% for octoploids. These measurements indicate that the association is widespread within the sampled populations and that host chromosome-set number did not appear to impose an obvious barrier to colonization. The observations do not, however, establish whether the fungus provides measurable benefits to the grasses or how infection affects their performance under stress.

No Epichloë stromata—the reproductive structures associated with sexual reproduction and horizontal transmission—were observed in the field collections. Exploratory PCR nevertheless detected both MAT1-1 and MAT1-2 mating-type idiomorphs at each of the three sites. This combination indicates that mating types capable of sexual reproduction are present among the sampled endophytes, but it does not demonstrate that sexual reproduction is occurring. The authors suggest that the endophyte may persist mainly through vertical transmission within seeds, while noting that asexual conidia might also permit water-mediated dispersal. Determining whether epiphytic conidia are produced on F. rothmaleri and how often stromata arise would be necessary to distinguish these possibilities. The mating-type result also does not rule out occasional hybridization involving other Epichloë species, although the study found no direct evidence for such events in this system.

Cultured isolates formed white, fluffy mycelium with variable appearance, but their growth rates did not differ significantly according to source population, host ploidy or the interaction between those factors. The mean growth rate across all isolates was 1.69 ± 0.21 millimetres per day. Fine-scale measurements of asexual structures did reveal variation, particularly among conidia, although individual identity accounted for the largest share of morphological variation in the permutation analysis. Average conidial length, width and area differed only marginally between two broad groups, while conidiophore width remained essentially unchanged. Conidia from isolates associated with hexaploid and some tetraploid hosts were generally smaller than those from the mixed Candelario population, and the smallest conidia and conidiophores occurred among the hexaploid-host isolates.

Multivariate analyses separated isolates more clearly by source population than by host ploidy in principal component analysis, and the first two components explained 86.6% of variation at the individual level. By contrast, linear discriminant models classified groups most successfully according to host ploidy, reaching a cross-validated accuracy of 68.8% with a kappa value of 0.459. Neither result indicates that morphology is a definitive marker of the host cytotype, because variation within groups was substantial and models based on the combined effects of population and ploidy had the weakest discriminatory power. The researchers also developed image-analysis software to measure conidial area automatically, reporting an overall mean area of 7.1 ± 1.0 micrometres squared. This digital morphometric approach was designed to make measurements more scalable and consistent, although the biological meaning of the observed host-associated patterns remains unresolved.

The fungal genome-size assay provided the strongest evidence that the isolates belonged to a common ploidy state. DAPI staining showed that every evaluated conidium contained a single nucleus, and flow cytometry produced reliable results only during the first 6–10 days of culture. Mean DNA content was 0.044 ± 0.002 pg/1C in isolates from Montemayor del Río tetraploids, 0.045 ± 0.002 pg/1C from Candelario tetraploids, 0.045 ± 0.003 pg/1C from El Cabaco hexaploids and 0.046 ± 0.002 pg/1C from Candelario octoploids. No significant differences were detected among populations or host cytotypes. The authors describe this as the first flow-cytometry estimate of Epichloë genome size and converted the common mean of about 0.045 pg/1C to approximately 42.8 megabases. That value is larger than some published E. festucae assemblies but remains within the range reported for haploid Epichloë genomes; comparisons across genera should nevertheless account for differences among sequencing and flow-cytometry methods.

Phylogenetic evidence supported the morphological and cytological identification of the fungus. Eight newly sequenced isolates were analyzed at five nuclear loci—actG, calmodulin, ITS, tefA and tubB—alongside reference Epichloë specimens and two Claviceps purpurea outgroups. Single-locus trees placed all new samples within a strongly supported E. festucae clade. Calmodulin and tubB also grouped the F. rothmaleri isolates into a subclade, with bootstrap support of 98% for calmodulin and 74% for tubB. Two polymorphic positions in the calmodulin alignment were specific to the new samples, suggesting that they could serve as candidate barcodes for this lineage. A concatenated maximum-likelihood tree and a multispecies-coalescent tree constructed with ASTRAL-III produced broadly congruent topologies. Support for the finer placement of the new lineage ranged from high in the coalescent analysis to moderate in the concatenated tree, while the broader E. festucae clade received strong support in both analyses. The authors note that the modest number of loci requires caution when interpreting some gene-tree and site-concordance values.

Taken together, the results document a polyploid host paired with a haploid endophyte across tetraploid, hexaploid and octoploid F. rothmaleri. This contrasts with other Festuca–Epichloë systems in which increased genomic complexity has been reported in both partners. The study establishes a baseline for future work rather than a complete account of the association: it did not test alkaloid profiles, fungal gene expression, plant fitness, drought tolerance, pathogen resistance or grazing responses, and it did not observe the long-term transmission of a single clonal fungal genotype through host generations. Nonetheless, its cytogenetic, morphological and molecular results show that the same E. festucae lineage can persist across markedly different host genome sizes. The system therefore offers a useful framework for asking whether polyploidy alters the endophyte’s metabolism or ecological effects without requiring a corresponding change in fungal ploidy, while the new conidial image-analysis and flow-cytometry methods may help investigators compare these traits more efficiently in other grass–endophyte associations.

Subject of Research: Characterization of a haploid Epichloë festucae strain associated with three polyploid Festuca rothmaleri cytotypes.

Article Title: Unveiling an asymmetric plant–fungal symbiosis: morphological, cytogenetic, and molecular characterization of a haploid Epichloë festucae strain associated with three polyploid cytotypes of the Iberian endemic grass Festuca rothmaleri

Article References: Sotomayor-Alge, A., Inda, L. A., Ángel-Beamonte, E., Zabalgogeazcoa, Í., & Catalán, P. (2025). Unveiling an asymmetric plant–fungal symbiosis: morphological, cytogenetic, and molecular characterization of a haploid Epichloë festucae strain associated with three polyploid cytotypes of the Iberian endemic grass Festuca rothmaleri. IMA Fungus, 16, Article e162692. https://doi.org/10.3897/imafungus.16.162692

Image Credits: AI Generated

DOI: 10.3897/imafungus.16.162692

Keywords: Epichloë festucae, Festuca rothmaleri, plant–fungal symbiosis, polyploidy, ploidy asymmetry, endophyte, flow cytometry, genome size, phylogenetics, Iberian endemic grass, Unveiling, asymmetric

The researchers prospectively enrolled children aged 6 months to 15 years who were admitted to the pediatric burn service at UF Health Shands Children’s Hospital between December 2023 and July 2025. The cohort included 14 children with small burns and nine with moderate burns. Seven healthy controls younger than 16 were undergoing elective pediatric surgery. The investigators collected blood from burn patients on hospital day 2, with a window of one day either side, and obtained later samples when clinically feasible. Control blood was collected in the operating room after induction of anesthesia and before surgery. Because sampling times were partly determined by each child’s clinical course, serial specimens were not available from every participant at every interval, and the number included in each immune assay varied.

Monocyte HLA-DR was measured by flow cytometry in circulating CD14-positive monocytes. The researchers converted median fluorescence intensity into the average number of anti-HLA-DR antibodies bound per cell, a measure reported as ABC. This analysis included seven controls, 11 small-burn patients and six moderate-burn patients. Median HLA-DR expression was significantly lower in the moderate-burn group than in healthy controls, while the small-burn group did not differ significantly from either comparison group after statistical correction for multiple comparisons. The estimated Hodges–Lehmann location shift between the moderate-burn and control groups was minus 22,939 ABC, with an exact 96.50% confidence interval from minus 33,104 to minus 12,039. Individual values varied considerably, including substantial overlap between the small-burn and moderate-burn groups.

The investigators also assessed whether burn injury altered circulating myeloid-derived suppressor cells, or MDSCs, a heterogeneous collection of immature myeloid cells described in the study as having immunosuppressive activity. Flow-cytometric phenotyping of peripheral blood mononuclear cells was performed approximately one week after injury in seven controls, six small-burn patients and six moderate-burn patients. Total MDSCs and three subsets—monocytic, polymorphonuclear and early MDSCs—showed considerable person-to-person variation. Some measures appeared numerically higher in the moderate-burn group, but neither total frequencies, subset frequencies nor absolute subset counts differed significantly among the three groups. Absolute total MDSC counts were numerically higher in moderate-burn patients, with a median of 253,685 compared with 161,336 in controls and 117,892 in the small-burn group, but the difference was not statistically significant.

Functional responsiveness was tested with a whole-blood TNF-α ELISpot assay. Diluted blood was incubated for 24 hours with or without LPS, and spots representing TNF-α-secreting cells were counted and characterized. The day-2 analysis included seven controls, seven small-burn patients and eight moderate-burn patients. LPS increased the number of spots, their size and total expression within every cohort, demonstrating that all three groups retained the capacity to respond to the stimulus. Among stimulated samples, however, the moderate-burn group produced the strongest responses. Stimulated spot-forming units, spot size and total expression were significantly higher than in controls, while total expression was also significantly higher than in the small-burn group. The small-burn cohort did not differ significantly from controls.

The magnitude of the acute functional differences was appreciable. The estimated shift in stimulated spot-forming units between moderate-burn patients and controls was 294, with an exact 95.99% confidence interval of 36 to 506. The corresponding shifts were 1.203 for stimulated spot size, with a confidence interval of 0.3966 to 2.521, and 2,503 for total expression, with a confidence interval of 974.7 to 3,686. Compared with small-burn patients, the estimated difference in total expression was 2,229, with a confidence interval of 403.2 to 3,473. These results indicate that the heightened response was specific to the moderate-burn group in this cohort rather than evidence of a general rise in every burned child.

Exploratory analyses suggested that immune measures might also differ among children with and without inpatient complications, defined in the study as graft loss, wound infection, gastrointestinal infection or bacteremia. Among burn patients with available data, those who experienced complications had larger burns: a median of 25% TBSA, compared with 11% among those without complications. Those with complications also had lower day-2 monocyte HLA-DR expression, with a median of 28,603 ABC versus 40,910 ABC. Whole-blood LPS-induced TNF-α responses did not differ significantly by complication status. These observations were exploratory, and burn size was greater in the complication group, making it difficult to separate the independent effects of severity, clinical interventions and immune markers.

Only three moderate-burn patients provided samples for a descriptive comparison at six to eight weeks after injury. Their later samples showed lower spot-forming units and total TNF-α expression than their acute day-2 samples, while spot size appeared similar. The small and incomplete dataset was not subjected to inferential testing and cannot establish how immune responsiveness changes during recovery. It nevertheless points toward a possible difference between acute and later responses. More broadly, the assays captured different immune domains: monocyte HLA-DR was a cell-specific phenotypic measurement, whereas whole-blood ELISpot responses reflected an integrated cytokine response from multiple blood-cell populations and did not identify the cellular source of TNF-α.

The study has important limitations. It was conducted at a single center with modest, assay-specific sample sizes, making it underpowered for modest differences and limiting generalizability. Nonsignificant results should not be interpreted as proof of equivalence. The cohort was predominantly male, no healthy control was African American, controls underwent diverse elective operations, and burn care—including surgery, transfusion, antibiotics, nutritional support and intensive care—varied with severity. The study was not designed to isolate those interventions’ effects. Burn depth was mixed, longitudinal sampling was incomplete, T-regulatory cells were not measured, and broader cytokine profiling and leukocyte functions such as phagocytosis, reactive oxygen species production and migration were not systematically assessed. All 30 participants were ultimately discharged in stable condition, and the research characterized early immune patterns rather than establishing that any marker predicts infection or other outcomes. Taken together, the results indicate that moderate pediatric burns were associated with concurrent phenotypic and functional innate immune alterations, rather than a uniformly weakened immune response.

Subject of Research: Early innate immune alterations in children with small and moderate burn injuries

Article Title: Moderate pediatric burn injury is associated with reduced monocyte HLA-DR expression and heightened whole-blood LPS-induced TNF-α responses

Article References: Wiggins, W. B., Rincon, J. C., Hernández-Ríos, M., Polcz, V., Rodhouse, C., Yoham, A. L., Richter, S., Cabral, A., Moldawer, L. L., Efron, P. A., Maile, R., & Larson, S. D. (2026). Moderate pediatric burn injury is associated with reduced monocyte HLA-DR expression and heightened whole-blood LPS-induced TNF-α responses. Frontiers in Pediatrics, 14, Article 1967322. https://doi.org/10.3389/fped.2026.1967322

Image Credits: AI Generated

DOI: 10.3389/fped.2026.1967322

Keywords: pediatric burns, innate immunity, monocyte HLA-DR, TNF-alpha, lipopolysaccharide, ELISpot, flow cytometry, myeloid-derived suppressor cells, immune dysregulation, Moderate, pediatric, burn

The investigators adapted a flow-cytometry-based pulse-chase labeling method to distinguish yeast cells according to their replicative histories and measure their survival under harsh environmental conditions. Baker’s yeast divides asymmetrically, allowing mother and daughter cells to be separated experimentally; mother cells typically stop budding after about 15–25 events under optimal conditions. Because yeast suspensions consist mainly of young cells, this approach provided a way to examine whether cells at earlier stages of their reproductive lives already differed in stress resistance. The experiment therefore addressed an early phase of replicative aging in a yeast model, rather than measuring only the final cessation of cell division.

The age-related pattern was consistent across all nine stress conditions tested: older cells experienced higher stress-induced mortality than younger cells. This suggests that loss of stress resistance begins as a gradual, replicative-age-dependent process and can generate heterogeneity within a clonal population, even when its members share the same ancestry. The study does not establish what cellular changes produce this decline or whether the same pattern occurs in animals or humans. Its results concern survival under the particular stresses examined and should not be interpreted as a general measure of lifespan or as evidence of a clinical benefit.

Tests of three established genetic determinants of replicative lifespan showed that they were largely unable to account for the early decline in stress resistance. Depleting mitochondrial DNA altered baseline stress resistance under some conditions but generally preserved the age-dependent decline across the tested stresses. Deleting FOB1, which extends replicative lifespan under optimal conditions, did not markedly alter the decline under either heat shock or acetic acid stress. Deleting SIR2, which shortens replicative lifespan, produced a steeper age–mortality relationship under acetic acid stress but not under heat shock. Together, these findings indicate that the genetic determinants of maximum replicative lifespan examined in the study differ from those controlling the early loss of stress resistance, although SIR2 can affect the latter in a stress-dependent manner.

Subject of Research: Experimental study of early replicative aging and stress resistance in budding yeast

Article Title: Established determinants of replicative lifespan, including mitochondrial DNA, play a limited role in early yeast stress-resistance decline

Article References: Azbarova, A. V., Galkina, K. V., & Knorre, D. A. (2026). Established determinants of replicative lifespan, including mitochondrial DNA, play a limited role in early yeast stress-resistance decline. Biogerontology, 27(6), Article 182. https://doi.org/10.1007/s10522-026-10528-8

Image Credits: AI Generated

DOI: 10.1007/s10522-026-10528-8

Keywords: budding yeast, replicative aging, stress resistance, mitochondrial DNA, SIR2, FOB1, flow cytometry, acetic acid stress, heat shock, cell mortality, Established, determinants

The study drew on 4,209 volunteers recruited between January 2022 and December 2023 through the First Affiliated Hospital of Guangzhou Medical University (Loudi Hospital), including 2,898 women and 1,311 men. All participants were healthy controls screened to exclude active immune disorders, malignancies, recent infections, and immunosuppressive therapy. Researchers measured ten immune parameters in peripheral blood using flow cytometry, covering total T cells, CD4+ and CD8+ T cell subsets, the CD4/CD8 ratio, B cells, natural killer cells, NKT cells, and expression of the checkpoint molecule PD-1 on several cell types.

Because raw immune measurements rarely follow a normal distribution, the team applied Box-Cox transformations and Tukey’s method to remove outliers before analysis, leaving between 4,123 and 4,204 reference individuals per parameter. Age-related trends were then examined with sex-stratified smooth curves and non-parametric tests, and a 1:1 propensity score matching procedure was used to build age-balanced male and female cohorts for direct comparison.

The headline finding is a sharp sexual dimorphism in B cell dynamics. In women, the proportion of CD19+ B cells rose with age, while in men it fell, producing opposite trajectories that the authors link tentatively to hormonal regulation and X-chromosome-encoded immune genes. After age matching, women had significantly higher B cell percentages than men, but a stratified analysis showed this gap was not significant before age 50 and only emerged after menopause, pointing to the postmenopausal window as the critical period.

T cell subsets told an equally striking story. In women, CD4+ helper T cells and the CD4/CD8 ratio climbed to a peak in the 55-to-59-year age group, while CD8+ cytotoxic T cells declined steadily across the lifespan. The authors describe this as a “scissor-like” pattern that closely parallels the abrupt drop in estrogen levels around menopause. Because hormone levels were not directly measured, they caution that this mechanistic interpretation remains speculative, but the timing of the immune shift aligns closely with the typical age of menopause as defined by the STRAW+10 staging framework.

PD-1, an immune checkpoint molecule best known as the target of modern cancer immunotherapies, showed a complex, cell-type-specific pattern. Women had lower PD-1 expression on CD4+ T cells and NK cells but higher PD-1 on CD8+ T cells, and the proportion of CD8+ PD-1+ cells showed a transient peak in the 60-to-64-year group. The authors suggest this may mark a window of heightened functional dysregulation in cytotoxic immunity, with potential relevance for how immune checkpoint status should be interpreted across demographic groups.

Innate immunity shifted as well. Natural killer cell percentages increased with age in both sexes, but the rise was markedly steeper in men, and the fraction of NK cells expressing PD-1 declined significantly with age in women. NKT cells, by contrast, showed no significant age-related trend. After age matching, women had higher NK cell and NKT cell proportions than men, alongside their higher CD4/CD8 ratios, reinforcing the picture of two distinct immune aging trajectories.

The findings carry practical implications. Because women generally mount stronger vaccine responses but suffer more autoimmune disease, and because PD-1 expression shapes anti-tumor immunity and postoperative infection risk, the authors argue that both sex and reproductive stage should be factored into studies of immune aging and into interventions such as vaccination strategies for middle-aged women. The observed B cell persistence in older women may represent a distinctive adaptive feature of female immunosenescence, though its consequences for humoral immunity remain to be tested.

The study has clear limitations. It is cross-sectional, so it captures age-related differences between individuals rather than tracking immune changes within the same person over time. Without menstrual records or hormone measurements, the researchers could not formally stage participants under STRAW+10 and instead used age groups as an approximation, meaning the 50-to-54-year group inevitably mixes perimenopausal and early postmenopausal women. The authors call for longitudinal studies that pair hormone monitoring with systematic reproductive staging to confirm whether the menopausal transition itself drives the immune shifts observed here.

Even with those caveats, the scale of the cohort and the consistency of the sex differences make a strong case that immunosenescence is not a single process but two, diverging sharply at midlife. For a field in which clinical trial populations and reference ranges have historically skewed male, the message is that middle-aged women may need their own immunological yardsticks, and that menopause deserves a place alongside chronological age as a variable in immune research.

Subject of Research: Sex differences in lymphocyte subset changes during the menopausal transition and immunosenescence

Article Title: Dynamic Shifts in Lymphocyte Subsets During the Menopausal Transition and Sexual Dimorphism in Immunosenescence

Article References: Xuan, C., He, L., Bohan, Z., Junming, X., Qingchao, L., & Junting, H. (2026). Dynamic Shifts in Lymphocyte Subsets During the Menopausal Transition and Sexual Dimorphism in Immunosenescence. Immunity, Inflammation and Disease, 14(10), Article e70558. https://doi.org/10.1002/iid3.70558

Image Credits: AI Generated

DOI: 10.1002/iid3.70558

Keywords: immunosenescence, menopause, lymphocyte subsets, PD-1, T cells, B cells, natural killer cells, sexual dimorphism, flow cytometry, estrogen, immune aging, propensity score matching

The research team, led by Belen Gimeno-Molina and Lynne Sykes, set out to examine how the maternal immune system interacts with the cervicovaginal microbiota in women at high risk of spontaneous preterm birth. Rather than simply measuring which bacteria were present, the investigators asked a subtler question: which of those bacteria were being recognized and bound by immunoglobulins, the antibody molecules that patrol mucosal surfaces throughout the body. Immunoglobulins are known to be present in cervicovaginal fluid, and previous work had shown that concentrations of IgG, the most abundant antibody class in blood and tissues, are lower in women whose vaginal communities are dominated by Lactobacillus species compared with women carrying more diverse, Lactobacillus-depleted communities. What remained unclear was whether these antibodies played any role in determining pregnancy outcome.

To answer that question, the team studied 100 women considered to be at high risk of spontaneous preterm birth, of whom 48 ultimately delivered preterm and 53 delivered at term. Using flow cytometry, a technique that allows individual bacterial cells to be sorted and analyzed one by one, the researchers could quantify precisely what proportion of the bacteria in each woman’s cervicovaginal fluid was coated with antibodies. The bacteria were first stained with a fluorescent dye that labels all microbial cells, and then fluorescently tagged antibodies against human IgG and IgA were used to detect immune binding. A carefully optimized gating strategy allowed the team to distinguish genuinely coated bacteria from background fluorescence, and control experiments confirmed that relevant vaginal species, including Lactobacillus crispatus, Lactobacillus iners and Gardnerella vaginalis, could be reliably detected by the method.

The results overturned a common assumption. Antibody coating is usually interpreted as a sign that the immune system is fighting an invader, yet in this study the highest proportions of IgG-coated bacteria were found in women whose vaginal communities were dominated by Lactobacillus, and especially by Lactobacillus crispatus, the species most consistently associated with reproductive health. In contrast, women with high-diversity, Lactobacillus-depleted communities, classified as community state type IV, showed lower levels of bacterial coating. In other words, the antibody response appeared to be directed at, or at least coexisting with, the microbes considered most protective rather than at the potentially harmful ones.

Delving deeper into the antibody classes involved, the researchers found a strong positive correlation between total IgG coating and coating by the IgG2 subclass, indicating that IgG2 was the dominant antibody subtype bound to the vaginal bacteria. This detail matters because different IgG subclasses recruit different arms of the immune system. IgG2 is typically associated with responses to polysaccharide antigens and tends to be less inflammatory than subclasses such as IgG1 or IgG3. Consistent with a calming rather than an activating role, the percentage of bacteria coated by IgG and IgG2 was significantly higher in women who delivered at term compared with those who delivered preterm, and the degree of IgG coating correlated negatively with the concentrations of pro-inflammatory immune mediators measured in the cervicovaginal fluid. Women with more antibody-coated bacteria, in short, carried less inflammation in the very compartment where labor is thought to be triggered.

Having established that antibodies were binding to Lactobacillus crispatus, the team went hunting for the molecular targets. Bacteria of this species decorate their surfaces with so-called S-layer proteins, or SLPs, a crystalline lattice of proteins that forms the outermost layer of the cell wall. When the researchers tested whether antibodies from the cervicovaginal fluid and from blood plasma could recognize these proteins, they found that both IgG and IgG2 bound to the S-layer proteins of Lactobacillus crispatus. There was considerable variability between individual women in the levels of antibodies directed against the two S-layer proteins studied, but the identification of these proteins as antibody targets provides the first concrete molecular handle on how the immune system might engage a beneficial vaginal bacterium in a way that is associated with immune homeostasis.

The authors interpret these findings as evidence of a mucosal microbe-immune homeostasis: a state in which the host immune system and the dominant microbial residents coexist in a regulated equilibrium. In this model, IgG coating of Lactobacillus crispatus is not a sign of conflict but of recognition, a form of immune engagement that coincides with low inflammation and, ultimately, with delivery at term. The study cannot prove causation, since it is observational and the antibody coating may be a consequence rather than a cause of a stable microbial community, but the association with pregnancy outcome held even within a cohort of women all considered high risk, which strengthens the biological plausibility of the link.

The work also reframes how scientists think about antibody responses at mucosal surfaces more broadly. In the gut, IgA coating of commensal bacteria is well established as a mechanism that keeps beneficial microbes in place and prevents them from triggering inflammation, a phenomenon sometimes described as immune inclusion rather than immune exclusion. The new findings suggest that an analogous process may operate in the vagina during pregnancy, with IgG, rather than IgA, taking the leading role. Notably, the researchers found that IgA coating did not differ significantly between women delivering at term and preterm, underscoring that the IgG response, and specifically its IgG2 component, is the signal most tightly linked to outcome.

Translational implications follow naturally from the identification of S-layer proteins as candidate antibody targets. If specific antibody profiles against Lactobacillus crispatus SLPs turn out to predict term delivery, they could form the basis of a biomarker test to identify which high-risk women are most likely to benefit from interventions aimed at establishing or maintaining a Lactobacillus crispatus-dominated vaginal community. Longer term, the S-layer proteins themselves might even serve as targets for therapies designed to encourage the immune system to embrace, rather than reject, the vaginal microbiota most associated with healthy pregnancy. The team cautions that much more work is needed, including longitudinal studies in larger and more diverse populations and experiments that directly test whether antibody coating influences bacterial function, before any clinical application can be contemplated.

For now, the study adds an important piece to the growing picture of pregnancy as a state of carefully negotiated coexistence between mother and microbes. Spontaneous preterm birth has resisted decades of effort to find reliable predictors and preventive treatments, and most research has focused on the inflammatory side of the equation, cataloguing the bacteria and immune signals present when labor begins too soon. By turning attention to the quieter half of the story, the antibodies that recognize and apparently tolerate a health-associated bacterium, the Imperial College team and their collaborators suggest that protection against early birth may lie not only in the absence of harmful inflammation but in the presence of a specific, measured immune engagement with the microbes women already carry. The 100 women who contributed samples to the study, recruited through the Imperial Academic Health Science Centre Women’s Health Research Centre, have thereby helped reveal that the boundary between immune defense and immune partnership is far blurrier than textbooks once implied, and that understanding that boundary may prove essential to keeping pregnancies on schedule.

Subject of Research: IgG antibody coating of Lactobacillus crispatus in the cervicovaginal microbiota and its association with immune homeostasis and reduced preterm birth

Article Title: IgG coating of Lactobacillus crispatus is associated with cervicovaginal immune homeostasis and reduced preterm birth rates, identifying S-layer proteins as candidate antibody targets

Article References: Gimeno-Molina, B., Decout, A., Love, R. L., Lee, Y. S., Ng, S., Malik, Z., Chan, D., Roberts, L. A., Bura, S., Mountain, K. E., Bayar, E., David, A. L., Terzidou, V., Marchesi, J. R., MacIntyre, D. A., Bennett, P. R., Collado, M. C., & Sykes, L. (2026). IgG coating of Lactobacillus crispatus is associated with cervicovaginal immune homeostasis and reduced preterm birth rates, identifying S-layer proteins as candidate antibody targets. Microbiome. https://doi.org/10.1186/s40168-026-02549-9

Image Credits: AI Generated

DOI: 10.1186/s40168-026-02549-9

Keywords: preterm birth, vaginal microbiota, Lactobacillus crispatus, IgG, immunoglobulin coating, S-layer proteins, cervicovaginal fluid, immune homeostasis, flow cytometry, mucosal immunity, pregnancy, microbiome

The study focused on colonies collected in Ouro Preto, in the southeastern Brazilian state of Minas Gerais, a mountainous region sitting at more than 1,150 meters above sea level. Between October and December 2020, the researchers located fire ant nests by their characteristic mounds of soil in grassy, sunny, open areas, marking four colonies for sampling. Importantly, the team never removed an entire colony; only fractions were collected so the brood could recover. Back in the laboratory, the researchers isolated post-defecating larvae, the developmental stage just before pupation, and dissected out the cerebral ganglion, the brain tissue where dividing cells could be captured for chromosomal analysis.

Preparing the chromosomes required a delicate protocol refined over decades of ant cytogenetics. The dissected ganglia were incubated in a hypotonic colchicine solution, a chemical that halts cells in the middle of division and allows chromosomes to condense into visible, countable structures. The tissue was then gently ruptured on a slide, and a series of acetic acid and ethanol solutions was dropped onto the preparation to spread the cells flat. After staining with Giemsa, the slides were examined under an optical microscope, and a total of 450 metaphase spreads, snapshots of chromosomes at their most condensed state, were photographed and counted across the four colonies.

The chromosome counts revealed a striking picture. Across all colonies, the researchers recorded haploid cells with 16 chromosomes, diploid cells with 32, tetraploid cells with 64, and, in a single remarkable metaphase, an octoploid cell with 128 chromosomes. The modal numbers, those observed most frequently, were the haploid and diploid counts, as expected, while the tetraploid class appeared at lower but consistent frequency. Notably, polyploid cells turned up in every colony examined, at similar frequencies, indicating that the phenomenon is not a random accident in one nest but a regular feature of the species’ biology during its immature stages.

To characterize the fine structure of the chromosomes, the team performed a karyomorphometric analysis, measuring the total length of each chromosome, the lengths of its short and long arms, and the ratio between those arms. These measurements allowed each chromosome to be classified as metacentric, submetacentric, or subtelocentric according to the position of its centromere, the pinched region that separates the arms. The resulting karyotypic formulas were elegantly consistent: the haploid complement comprised 10 metacentric, 4 submetacentric, and 2 subtelocentric chromosomes, the diploid complement doubled that arrangement, and the single tetraploid metaphase analyzed followed the same doubling pattern. The two largest metacentric and submetacentric pairs also displayed secondary constrictions, landmarks on the chromosome that often correspond to nucleolus organizer regions, sites of intense ribosomal RNA gene activity.

Chromosome counting alone cannot confirm true genome multiplication, so the researchers turned to flow cytometry, a technique that measures the DNA content of thousands of individual nuclei by their fluorescence. Brain tissue from larvae was ground in buffer, filtered, and stained with propidium iodide, a dye that binds DNA, with fruit fly Drosophila melanogaster serving as an internal calibration standard. At least 10,000 nuclei per sample were analyzed on a FACSCalibur cytometer, with three independent replicates per colony and strict quality controls rejecting any histogram with excessive variability. The resulting histograms showed not only the expected peaks for unreplicated and replicated diploid nuclei but also additional, evenly spaced peaks corresponding to 8C and 16C DNA contents, a clear signature of endoreduplicated, polyploid cell populations.

The flow cytometry data also yielded the first precise estimate of genome size for this species: 0.51 picograms of DNA per haploid genome, equivalent to roughly 498.78 megabase pairs. This value agrees with earlier estimates for related fire ants and reinforces the consistency of the cytogenetic picture. Polyploidy is, in fact, common in plants but decidedly rare in animals, which makes its regular appearance in fire ant larvae all the more intriguing. Previous surveys of fungus-farming ants, for example, failed to detect polyploid cells even with similar flow cytometry approaches, hinting that the phenomenon may be restricted to particular ant lineages rather than being widespread across the family Formicidae.

What functional advantage might polyploid cells confer on a developing ant colony? The researchers draw an analogy to the salivary glands of dipteran flies, where endoreplication produces giant polytene chromosomes packed with thousands of DNA strands, fueling massive secretory output. In fire ants, the extra gene copies in polyploid cells could accelerate the developmental rate of immature workers, allowing the brood to mature faster. Because fire ant colonies are recruiting species, in which workers signal and recruit nestmates to food resources, a faster-growing workforce means a colony can exploit its environment more rapidly, reach reproductive maturity sooner, and flood the surroundings with the winged sexuals that found new colonies. In evolutionary terms, the faster a colony converts resources into dispersing offspring, the higher its fitness, and ploidy variation in the brood stage may be one cytogenetic lever behind that speed.

The mechanism behind the polyploid cells likely involves endomitosis, a modified cell cycle in which DNA replication proceeds normally but the final step of cell division, cytokinesis, never occurs. Chromosomes accumulate within a single nucleus, generating cells with doubled, quadrupled, or octupled genome complements. Conserved developmental programs control this process in both animals and plants, and a growing body of work suggests that endoreplication provides essential biological functions during development. Intriguingly, earlier doctoral research cited by the team showed that polyploid cells in this species disappear as larvae progress to pupae and adults, meaning the phenomenon is confined to the mutable, rapidly growing immature phase, precisely the stage when accelerated growth would matter most.

Beyond its developmental implications, the study carries weight for taxonomy and invasion biology. Solenopsis is a notoriously difficult genus of more than 190 described species, whose workers lack the morphological features needed for reliable classification, and cryptic species may lurk within the fire ants now spreading across the Americas and Oceania. Karyotyping offers a powerful genetic marker where morphology fails, and the confirmation that n = 16 is the standard haploid number for S. saevissima, matching counts in congeners such as S. invicta, S. geminata, and S. richteri, strengthens the case that this chromosome number is a shared signature of the genus. With only about 7 percent of the world’s more than 16,000 ant species cytogenetically analyzed, studies like this one fill a vast gap, and they hint that chromosomal flexibility, whether through polyploidy or hybridization-driven genome shuffling, may be one of the quiet secrets behind the fire ant’s global conquest. The authors caution that the adaptive role of polyploid cells remains a hypothesis that will require testing in field studies, but the image of a tiny ant larva quietly packing 128 chromosomes into a single brain cell is a vivid reminder that some of invasion biology’s most important answers may be written at the level of the chromosome.

Subject of Research: Polyploidy and karyotype structure in the fire ant Solenopsis saevissima

Article Title: Assessing ploidy levels and karyotype structure of the fire ant Solenopsis saevissima Smith, 1855 ( Hymenoptera , Formicidae , Myrmicinae )

Article References: de Andrade, A. R. M., Cardoso, D. C., & Cristiano, M. P. (2023). Assessing ploidy levels and karyotype structure of the fire ant Solenopsis saevissima Smith, 1855 (Hymenoptera, Formicidae, Myrmicinae). Comparative Cytogenetics, 17, 59-73. https://doi.org/10.3897/compcytogen.17.100945

Image Credits: AI Generated

DOI: 10.3897/compcytogen.17.100945

Keywords: fire ants, Solenopsis saevissima, polyploidy, cytogenetics, karyotype, flow cytometry, endoreplication, invasive species, chromosomes, genome size, Formicidae, Brazil

The research team, working with living material from the Active Germplasm Bank of Embrapa Eastern Amazon in Belém, Pará, Brazil, examined five species: Oenocarpus bacaba, O. bataua, O. distichus, O. mapora, and O. minor. These are the palms that matter most to Amazonian communities, valued for food, tools, utensils, and construction materials. Seeds from multiple accessions of each species were germinated under controlled conditions, and researchers analyzed root tip cells from the resulting seedlings. The work was authorized by Brazilian federal institutions, and voucher specimens were deposited in the IAN Herbarium in Belém, ensuring the study can be verified and built upon by future researchers.

The headline finding is a striking constancy. Every single species, regardless of how different the palms look in the forest, carries exactly 36 chromosomes in its somatic cells, written as 2n = 36. Only one of these species, O. bataua, had ever been counted before, and the new work confirmed that earlier report. For the other four, these are the first chromosome numbers ever published. In a family as vast as the palms, with roughly 2,400 species across 190 genera, such baseline data is remarkably scarce. The subfamily that contains Oenocarpus, called Arecoideae, is actually the least cytogenetically explored of all five palm subfamilies, with at least five tribes lacking chromosome counts entirely.

But the story does not end with the count. When the researchers constructed detailed karyotypes, organized portraits of each species’ full chromosome set, they discovered meaningful differences hiding beneath the identical numbers. The karyotype formulas varied: O. bacaba showed two metacentric, eleven submetacentric, and five acrocentric chromosomes, while O. bataua displayed eight metacentric and ten submetacentric chromosomes with no acrocentrics at all. O. distichus, O. mapora, and O. minor each had their own distinct formulas. The position of secondary constrictions, the pinched regions on chromosomes that mark the locations of nucleolus organizer regions carrying ribosomal DNA genes, also differed from species to species, appearing on different chromosome pairs in each one.

These differences matter because they point to a mechanism. The researchers infer that structural chromosome rearrangements, particularly translocations and pericentric inversions, accumulated during the evolution of the genus, reshuffling chromosome arms while leaving the total count untouched. Transposable elements, the mobile DNA sequences that can jump around genomes, may have contributed as well. This is evolution working at the architectural level: the same number of pieces, arranged in different ways. According to the classic framework of karyotype evolution developed by G. Ledyard Stebbins, such rearrangements are important drivers of speciation because they increase asymmetry within chromosome sets and help differentiate closely related lineages from one another.

The asymmetry analysis reinforced this picture. Using two independent classification methods, one from Stebbins and one from Zarco, the team quantified how uneven the chromosomes were within and between each species’ complement. O. bataua emerged as the most symmetrical, classified in category 2b with the lowest values for both intrachromosomal and interchromosomal asymmetry. Three species, O. distichus, O. mapora, and O. minor, clustered together in category 3b, forming a visibly similar group on a scatterplot of the two asymmetry indices. O. bacaba stood apart as the most asymmetrical of all five, landing in category 3c with the highest values on both measures. Whether that asymmetry signals a more derived karyotype or simply a different evolutionary trajectory remains an open question for future work.

The team also looked at how DNA is packaged when cells are not dividing, examining the resting state known as interphase. All five species displayed semi-reticulate interphase nuclei, characterized by strongly stained chromatin clumps called chromocenters with irregular edges. This matters more than it might sound, because in the palm family, interphase nucleus type has proven remarkably constant among related species, sometimes even at the level of whole tribes. The semi-reticulate pattern is considered typical of species with medium-sized chromosomes, roughly three to five micrometers long, which is exactly what the researchers measured. The finding slots Oenocarpus neatly into established patterns of chromatin organization across the Arecaceae.

Genome size told its own story, and a more restrained one. Using flow cytometry, a technique that lasers individual nuclei to measure their DNA content, the team estimated the 2C nuclear DNA amount for each species. The values ranged narrowly from 6.46 picograms in O. bataua to 6.96 picograms in O. minor, and statistical analysis found no significant differences among the five. That uniformity is notable given the wild variation across the palm family as a whole. Other arecoid palms show 2C values from under 4 picograms in the coconut palm to more than 27 picograms in Pinanga subintegra, a spread of more than fourteenfold among diploid palms. Within genera, however, DNA amounts rarely vary much, and Oenocarpus fits that rule perfectly.

One discrepancy adds a layer of scientific intrigue. The earlier study that counted O. bataua’s chromosomes also estimated its DNA content, using an older technique called Feulgen microdensitometry, and arrived at a value more than one picogram higher than the flow cytometry result reported now. The two methods estimate DNA differently, and while results often correlate, discrepancies between them have been documented in other plants without a settled explanation. The authors suggest that reanalyzing the original specimens with flow cytometry, or sampling more genotypes across the species’ range, would clarify whether the gap reflects methodology or genuine intraspecific variation, a phenomenon documented in the coconut palm. Genotype origin and technique both appear capable of nudging genome size estimates in palms.

For the Amazonian communities who depend on these palms, and for the plant breeders working to improve them, the study delivers practical groundwork. Chromosome numbers, karyotype formulas, and genome sizes are foundational data for characterizing germplasm banks and managing breeding programs, and they anchor cytotaxonomic classifications that help distinguish species and guide conservation. The constancy of 2n = 36 across the genus, matching counts in related members of the tribe Euterpeae, confirms Oenocarpus as a conservative lineage in chromosome number while revealing a dynamic history of structural rearrangement beneath the surface. The next chapter, the authors note, involves understanding the mechanisms driving karyotype differentiation in more detail and testing the phylogenetic relationships proposed for the genus. For now, five of the Amazon’s most useful palms finally have their cellular identities on record, and their chromosomes tell a story of stability on the outside and restless change within.

Subject of Research: Cytogenetics and nuclear DNA content of five Oenocarpus palm species

Article Title: Interphase nuclei, karyotypes and nuclear DNA amounts in five species of Oenocarpus ( Arecaceae )

Article References: Oliveira, N. P. D., Gesteira, G. D. S., Padilha de Oliveira, M. D. S., & Davide, L. C. (2024). Interphase nuclei, karyotypes and nuclear DNA amounts in five species of Oenocarpus (Arecaceae). Comparative Cytogenetics, 18, 59-72. https://doi.org/10.3897/compcytogen.18.117597

Image Credits: AI Generated

DOI: 10.3897/compcytogen.18.117597

Keywords: Oenocarpus, Arecaceae, cytogenetics, karyotype, flow cytometry, chromosome number, genome size, Amazonia, speciation, chromosome rearrangement, interphase nuclei, Arecoideae

The analyzer under evaluation, known as the MUS-1, uses a technique called flow cytometry to examine urine sediment. Instead of relying solely on chemical dipstick readings, it counts cells and bacteria directly under a microscope. The system then applies artificial intelligence to interpret the resulting images, classifying them as either likely positive or likely negative for urinary tract infection. This approach could allow laboratories to screen out negative cultures before they are set up, saving time and resources.

The study, published in the journal Clinical Chemistry and Laboratory Medicine, evaluated the MUS-1 on urine samples from patients suspected of having urinary tract infections. The researchers compared the analyzer’s results with conventional urine cultures, the gold standard for diagnosis. They found that the MUS-1 could correctly identify a substantial proportion of negative cultures, allowing them to be screened out before setup.

However, the results were far from perfect. The analyzer missed a notable number of positive cultures, meaning that some infections would have gone undetected if the MUS-1 were used as the sole screening tool. The researchers emphasized that the system should be used in combination with conventional cultures, not as a replacement for them.

The study also found that the MUS-1 performed better on urine samples from male patients than on samples from female patients. The researchers suggested that this difference might be related to variations in urine sediment composition between the sexes.

Despite these limitations, the researchers concluded that the MUS-1 represents a promising step forward in the effort to reduce unnecessary urine cultures. They emphasized that further studies are needed to confirm the system’s performance and to determine the best way to integrate it into laboratory workflows.

The study behind these findings was conducted at a tertiary hospital in Türkiye over a roughly two-week enrollment window in early 2024, during which 856 midstream urine specimens were collected from outpatient clinics and intensive care units. Each specimen was transported without delay and processed so that quantitative culture and automated analysis were performed on the same sample within an hour of laboratory arrival, with the MUS-3600 reading completed within ten minutes of collection. This tight timing matters, because delays between collection and analysis can allow bacteria to multiply or cells to degrade in the tube, artificially inflating particle counts and distorting the comparison against culture. After excluding 97 specimens judged contaminated by urethral flora, the final analysis rested on 759 samples from patients aged 18 to 96, split almost evenly between 409 female and 350 male participants, with the overwhelming majority, 96 percent, coming from outpatients.

The culture methodology followed conventional microbiological practice. Urine was plated on chromogenic agar and incubated at 35 to 37 degrees Celsius for 18 to 24 hours, with a threshold of at least 10,000 colony-forming units per milliliter for a single organism or each of up to two potential pathogens defining a positive result. Organisms were identified by MALDI-TOF mass spectrometry and susceptibility testing was carried out on a VITEK 2 Compact system, ensuring that the reference standard was robust and reproducible. Specimens yielding three or more species without a dominant organism were treated as contaminated and removed from the analysis, a standard safeguard against counting mixed urethral flora as infection.

The demographic pattern of the results deserves attention. Women made up nearly three-quarters of culture-positive cases, 72.5 percent, while men accounted for only 27.5 percent, a difference that was highly statistically significant. Median age was also slightly higher among culture-positive patients, 58 versus 54 years. These distributions help explain why the analyzer’s negative predictive value reached 93.9 percent in men but only 82.1 percent in women: when the pretest probability of infection is lower, as it was among the male samples in this cohort, a screening test naturally achieves a higher proportion of correct negative calls. This is a statistical property of predictive values rather than evidence that the instrument itself performs differently by sex, although differences in urine sediment composition between sexes may also contribute.

The particle-level data reveal why morphotype classification adds value. Median bacillus counts were 294 per microliter in culture-positive samples versus zero in culture-negative ones, and total bacteria medians were 1,080 versus 337.5 per microliter, both differences highly significant. Suspected coccus counts, while also statistically different, showed a much less dramatic separation, with medians of 650 versus 328 per microliter. This weaker discrimination likely underlies the poor screening performance of the suspected cocci parameter, which achieved only 44.4 percent sensitivity and 34.5 percent positive predictive value at its derived cutoff of 859 per microliter. Gram-positive organisms and contaminants can both appear as cocci on imaging, making this category intrinsically harder to interpret.

Chemical dipstick results provided complementary signals. Nitrite positivity was rare overall, 5.4 percent of samples, but when present it strongly indicated infection: 39 of 41 nitrite-positive specimens were culture-positive, whereas only 2 of 604 nitrite-negative culture-negative samples were falsely flagged. Leukocyte esterase positivity showed a similar directional pattern, with 64.7 percent of culture-positive samples testing positive compared with 19 percent of culture-negative ones. Neither chemical parameter alone was sufficient for screening, but the concordance between the imaging-based particle counts and the dipstick findings illustrates how multimodal urinalysis data could be combined in future algorithms.

The choice of a 10,000 colony-forming unit per milliliter threshold for positivity is itself consequential. Many laboratories use 100,000 units per milliliter for midstream specimens from symptomatic patients, and lower thresholds increase sensitivity for true infection at the cost of detecting more asymptomatic bacteriuria and low-count contamination. By adopting the stricter cutoff, the investigators classified more samples as positive, which raises the bar for the analyzer’s sensitivity figures. Had a higher threshold been used, some of the low-count positives that the analyzer missed might have been reclassified as negatives, potentially improving apparent screening performance. Readers comparing this study with other evaluations of automated urinalysis should therefore pay close attention to how culture positivity was defined.

The concept of an elimination rate, the proportion of culture-negative samples that the analyzer correctly identifies as negative and thus removes from the culture workload, is central to the economic argument for such systems. With a combined white blood cell and bacilli strategy, 77.2 percent of negative cultures could theoretically be eliminated, and the corresponding negative predictive value of 87.9 percent means roughly one in eight eliminated samples would actually harbor significant growth. Whether that error rate is acceptable depends on clinical context: for a healthy outpatient with uncomplicated symptoms, a 12 percent miss rate may be tolerable if clinicians retain the option to request culture, whereas for immunocompromised or pregnant patients it would likely be unacceptable.

It is also worth noting what the study excluded. Catheterized specimens, pediatric patients, samples with insufficient volume, and specimens with gross hematuria or mucus were all left out, and essentially no outpatients had received antibiotics before culture. Real-world populations include many patients whose antibiotic exposure suppresses bacterial counts, potentially widening the gap between analyzer readings and culture results. The narrow two-week enrollment at a single center likewise limits generalizability, and seasonal variation in circulating uropathogens could shift the balance of gram-positive versus gram-negative organisms, altering the relative value of the bacilli and cocci parameters.

The MUS-3600 itself integrates two modules, an H1600 urine chemistry analyzer and a FUS360 sediment analyzer, using flow-type micro-imaging in which particles are photographed in a flowing stream and classified by artificial intelligence algorithms. This differs from impedance- and fluorescence-based flow cytometry systems that have dominated prior evaluations of automated urine screening, and direct visual classification of bacterial morphotypes is a relatively new capability among commercial platforms. Independent validation in other laboratories, with different patient mixes and different local microbiology, will be needed before such morphotype-based cutoffs can be recommended broadly.

For now, the most defensible reading of the evidence is that the MUS-3600 functions as a rule-out aid rather than a rule-in test. Its negative predictive values, particularly the 93.9 percent figure in male outpatients, suggest it can meaningfully reduce culture volume in selected populations, while its modest sensitivity means positive or equivocal results must still trigger definitive culture. Laboratories considering adoption would need to establish their own cutoffs, monitor miss rates prospectively, and define clear escalation pathways so that no symptomatic patient is denied culture on the basis of a screening result alone.

Subject of Research: Laboratory Medicine

Article Title: Screening performance of the MUS-3600 urine analyzer for urinary tract infection: comparison with urine culture

Article References: Yalçınkaya Kara, Z. M., Genç, L., Odabaşı, M. S., & Aktaş, E. (2026). Screening performance of the MUS-3600 urine analyzer for urinary tract infection: comparison with urine culture. Acta Biochimica Polonica, 73, Article 16555. https://doi.org/10.3389/abp.2026.16555

Image Credits: AI Generated

DOI: 10.3389/abp.2026.16555

Keywords: urine culture, flow cytometry, artificial intelligence, laboratory medicine, diagnostics, Screening, performance, MUS-3600, urine, analyzer, urinary, tract