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Genome mining of alkaliphilic cyanobacterial consortia: identification of biosynthetic gene clusters in Sodalinema and associated heterotrophs.

Alkaline soda lakes are high-pH environments that host specialized microbial communities with potential for biotechnology and natural product discovery. We characterized three Sodalinema-dominated cyanobacterial consortia enriched from Canadian soda lakes over 510 days. Using hybrid metagenomic sequencing and metatranscriptomics across pH, alkalinity, and temperature gradients, we reconstructed high-quality metagenome-assembled genomes and assessed functional activity. All consortia converged toward cyanobacteria dominance and exhibited temperature optima between 21°C and 30°C. Phylogenetic analysis placed Sodalinema genomes within a distinct clade affiliated with Candidatus Sodalinema alkaliphilum. Genomic analysis indicated complete biosynthetic pathways for vitamin B5, vitamin B7, and the molybdenum cofactor, but incomplete pathways for vitamins B1, B9, and B12, consistent with patterns observed in Sodalinema yuhuli. Metatranscriptomic profiles showed increased expression of genes involved in phycocyanin and carotenoid biosynthesis at pH 10.2 relative to pH 8.5. Biosynthetic gene cluster analysis revealed that most secondary metabolic potential resided in heterotrophic community members. Roseinatronobacter encoded pathways for N-acyl homoserine lactones, osmoprotectants, betalactones, and prodigiosin, while Alkalimonas, Wenzhouxiangella, and members of the Kiloniellales encoded clusters for lanthipeptides, cyclodipeptides, hydrogen cyanide, and pyrroloquinoline quinone. These findings indicate functional partitioning within the consortia and highlight the contribution of heterotrophs to secondary metabolism.IMPORTANCEAlkaline soda lakes contain microbial communities adapted to high pH that remain underexplored for biotechnology. This study focuses on Sodalinema, a filamentous cyanobacterium that dominates enriched consortia from Canadian soda lakes, and its associated heterotrophic partners. We show that while Sodalinema drives primary productivity, heterotrophic bacteria encode most of the pathways for antimicrobial and signaling compounds. These interactions may support community stability and defense against competing microorganisms. By linking genomic potential with gene expression, this work identifies alkaline cyanobacterial consortia as a source of bioactive compounds and provides a framework for exploring extremophilic microbial communities for natural product discovery.

Sodalinema

Spatially confined electrochemical strategy with DNA-assembled nanogaps for SNP detection.

Accurate detection of low-abundance single nucleotide polymorphisms (SNPs) against a large excess of homologous wild-type sequences requires both selective molecular recognition and effective transduction of small sequence differences into measurable signals. Here, we report a spatially confined electrochemical strategy that couples sequence-selective recognition with size-dependent mass-transport gating. DNA-hybridization-driven self-assembly of gold nanoparticles (AuNPs) forms a three-dimensional self-assembled electrode (3D-SAE) with a DNA-defined interparticle architecture. Competitive probes (SP/WP) convert single-base recognition into distinct molecular-size states: the SNP-associated pathway preferentially triggers a hybridization chain reaction (HCR), generating bulky AuNP-anchored HCR/methylene blue complexes (Au@HCR/MB) with reduced electrochemical accessibility through the porous 3D-SAE, whereas the wild-type pathway does not trigger HCR and maintains a high-current response from more readily accessible MB-containing species. Thus, sequence recognition is translated into a molecular-size difference and subsequently into an electrochemical signal through differential mass transport. Under buffer conditions, the platform achieved a statistically estimated detection limit of ∼0.47 fM and a quantitative range of 1 fM-100 pM. It discriminated a 0.1% mutant abundance in a fragmented genomic-DNA background. The downstream signal-transduction chemistry is enzyme-free and isothermal. This work establishes a mechanistical recognition-size-conversion-mass-transport-gating architecture for electrochemical nucleic acid analysis.

Polymorphism, Single Nucleotide

Measurable Residual Disease and the Unresolved Biology of Leukemic Stem Cells.

Measurable residual disease (MRD) testing has transformed the management of hematologic cancers by enabling detection of residual malignant cells after therapy. Current approaches rely on qPCR and next-generation sequencing to monitor leukemia-associated somatic mutations, while multiparameter flow cytometry identifies aberrant leukemic immunophenotypes. Although these methods provide valuable prognostic and therapeutic information, MRD negativity remains an imperfect surrogate for cure. Most MRD platforms evaluate CD45+, rapidly dividing leukemic populations and fail to detect quiescent cells that may survive cytotoxic therapies which efficiently target proliferating hematopoietic cells. Relapse frequently occurs despite deep molecular remission, suggesting persistence of rare leukemic stem cells (LSCs) that are intrinsically resistant to chemotherapy and targeted therapies. The paradox of relapse despite molecular remission could be explained by the presence of very small embryonic-like stem cells (VSELs) which are pluripotent, quiescent stem cells sitting at the top of cellular hierarchy in multiple adult tissues including bone marrow. A pluripotent VSEL divides through asymmetrical cell division to give rise to two cells of different sizes and fates, smaller cell is to self-renew while the bigger is lineage-restricted and tissue-committed progenitor which undergoes extensive epigenetic changes, divides rapidly and undergoes clonal expansion before further differentiation. Dysfunctions of VSELs initiate both solid and hematologic cancers. Based on this view, somatic mutations monitored during MRD assessment possibly represent downstream consequences of clonal expansion rather than the initiating drivers of disease persistence. Thus, exclusive monitoring of somatic mutations and CD45 + leukemic populations possibly overlook rare, small-sized, CD45- VSELs that contribute to therapeutic resistance and relapse.

Humans

From buffalo to human: Klebsiella pneumoniae in high-somatic cell count milk as an overlooked link in the one health chain.

High somatic cell count (SCC) is a critical indicator of udder health and milk quality in buffalo milk production. However, in many low-income regions, SCC monitoring is often underemphasized, allowing a proportion of high-SCC buffalo milk to enter the food chain and potentially compromising food safety and public health. Klebsiella pneumoniae (K. pneumoniae) is a common zoonotic pathogen found in high-SCC milk, yet systematic investigations into the prevalence and characteristics in high-SCC buffalo milk remain limited. In this study, 23 K. pneumoniae strains were screened out from 460 bacterial isolates obtained from high-SCC buffalo milk samples from Guangxi, China, with an isolation rate of 5.0%. These isolates were comprehensively characterized using whole-genome sequencing and comparative genomic analyses. The results revealed that 78.26% (18/23) of the isolates shared high genomic similarity with the human reference strain ATCC 13883, and the ST37 clone exhibited a pronounced potential of cross-species transmission. All isolates harbored core adhesion factors and intrinsic resistance genes. Notably, several strains displayed high-risk features: strain 419 carried the K1 capsular serotype, strain 326 possessed a complete yersiniabactin synthesis gene cluster, and strain 320 exhibited a multidrug-resistant phenotype. Phenotypic assays further demonstrated a positive correlation between biofilm formation capacity and virulence in Galleria mellonella. Metabolic pathway enrichment analyses suggested that K. pneumoniae has undergone substantial adaptation to the nutrient-rich buffalo milk environment. Collectively, these findings confirm that raw high-SCC buffalo milk serves as a significant reservoir for high-risk zoonotic K. pneumoniae. While industrial thermal processing effectively eliminates viable pathogens, the resilient antimicrobial resistance determinants within these isolates pose a persistent risk of horizontal gene dissemination along the food chain, providing critical evidence for enhancing pre-processing milk quality regulations within a One Health framework.

Animals

Vitamin D Supplementation Modulates Base Excision Repair (BER) Machinery in Systemic Sclerosis: A Prospective Longitudinal Study.

Systemic sclerosis (SSc) is a chronic, autoimmune, fibrotic disorder involving immune dysregulation, vascular abnormalities and progressive fibrosis. Although oxidative stress and defective DNA repair have been implicated in its pathogenesis, the impact of vitamin D on DNA repair pathways remains unclear. This study aimed to investigate the expression of DNA repair enzymes in SSc, explore their relationship with vitamin D status and assess the effects of vitamin D supplementation on the transcriptional expression of these enzymes. Peripheral blood samples were collected from 52 female patients with SSc and 31 age-matched healthy controls (HCs). Gene expression levels of base excision repair (BER) enzymes (APE1 and OGG1) and nucleotide excision repair (NER) enzymes (XPA and XPC) were analyzed. Serum vitamin D levels were measured and correlated with disease activity scores. In a prospective arm of the study, patients received six months of vitamin D supplementation and their DNA repair capacity was evaluated pre- and post-intervention. Baseline expression of APE1 and OGG1 was significantly lower in SSc patients than in HCs, whereas expression of the NER genes remained unchanged, indicating selective impairment of the BER pathway. Vitamin D deficiency was prevalent in SSc and inversely correlated with disease severity. Supplementation significantly increased serum vitamin D levels and up-regulated APE1 and OGG1 expression; while NER genes remained unaffected. These findings are consistent with evidence of elevated oxidative DNA lesions in SSc and support a mechanistic link between BER activity and the repair of oxidative DNA damage. SSc patients exhibit reduced transcription of BER-specific enzymes associated with vitamin D deficiency andrestoration of vitamin D levels partially rescues BER enzyme expression. These findingshighlight a potentially modifiable axis linking micronutrient status, genomic stability and disease activity and provide a rationale for investigating vitamin D optimization as an adjunctive strategy to enhance DNA repair and potentially attenuate inflammatory and fibrotic processes in SSc.

Humans

TNF-NF-κB signaling mediates immune-biomineralization crosstalk during shell repair under ocean acidification in Mytilus edulis.

Ocean acidification (OA) impairs biomineralization in bivalves, but its effects on immune-biomineralization crosstalk during shell repair remain unknown. Here, we exposed adult Mytilus edulis bearing standardized shell perforations to three pH levels (8.1, 7.9, and 7.7) for up to 40 days. OA slowed early repair and caused microstructural disorganization and an approximately 87% reduction of compressive strength at pH 7.7, yet the damaged area appeared largely closed by day 15, suggesting a decoupling between morphological closure and functional recovery. In addition, transcriptomic profiling of hemocytes and mantle tissue, based on an average of 6.5 Gb of clean reads per sample mapped to the M. edulis reference genome (NCBI Assembly GCF_000511035.1), revealed that these shell-level defects were accompanied by coordinated immune and metabolic reprogramming. Hemocytes, the primary immune effector cells of bivalves, exhibited pH- and time-dependent shifts with moderate acidification (pH 7.9) promoting inflammatory transcripts, whereas severe acidification (pH 7.7) suppressed these signals while upregulating stress-associated pathways; both treatments consistently downregulated lysosomal proteases and NF-κB negative regulators. The mantle, a primarily mineralizing organ, paradoxically upregulated immune-related genes while suppressing oxidative phosphorylation and extracellular matrix pathways. This tissue-level imbalance, with hemocytes recruited but functionally constrained and mantle metabolically suppressed yet immunologically activated, points to TNF-NF-κB pathway modulation as a key mediator of shell repair under acidification. Our findings demonstrate that visible shell closure masks underlying structural and mechanical failure, and that immune regulation, rather than simple suppression or activation, critically shapes the repair outcome. These results advocate for multifunctional indicators beyond closure area to assess shell integrity in acidified marine environments.

Animals

Prevalence of POMC allele associated with obesity in feline population in Vietnam.

Feline obesity is an increasingly important health problem influenced by both genetic predisposition and husbandry practices. This study investigated the prevalence and phenotypic relevance of the feline proopiomelanocortin (POMC) c.28G > C (p.Gly10Arg) variant in a Vietnamese cat population and evaluated environmental factors associated with obesity. A total of 63 clinically healthy cats were classified as normal weight (body condition score [BCS] 5-6/9; n = 40) or obese (BCS ≥7/9; n = 23). Genotyping was performed using a newly developed PCR-restriction fragment length polymorphism assay and validated by Sanger sequencing. Ventral subcutaneous adipose tissue (VSAT) thickness was measured ultrasonographically as an objective indicator of adiposity. Genotyping revealed a high prevalence of the risk-associated C allele, with 45/63 cats (71.4%) carrying the GC genotype and 18/63 (28.6%) carrying the CC genotype, whereas the GG genotype was not detected, giving a Callele frequency of 64.3%. Obese cats had significantly greater body weight and VSAT thickness than normal-weight cats. Neuter status and ad libitum feeding were significantly associated with obesity, whereas diet type, housing, exercise frequency, and begging behavior were not. Although genotype distribution did not differ significantly between normal and obese cohorts, obese CC cats showed significantly greater VSAT thickness than obese GC cats, indicating an allele-dosage effect on adiposity. These findings suggest that the POMC c.28G > C variant is a useful risk-informative marker and that combining genetic screening with objective fat assessment may support earlier identification and prevention of feline obesity in Vietnam under routine laboratory conditions and guide personalized management strategies in practice.

Animals

TNFα-dependent modulation of WT1-MMP9 regulatory axis links developmental and inflammatory pathways in glaucoma.

Glaucomas are heterogeneous optic neuropathies associated with extracellular matrix dysregulation, abnormal ocular morphogenesis, and inflammatory signaling. Targeted deep sequencing of 586 primary congenital glaucoma (PCG) cases and 1,757 controls identified rare pathogenic variants in multiple genes, including WT1 and MMP9. Notably, WT1 variants clustered within the nuclear export sequence. Further, functional analyses showed that combined wt1-pax6 suppression in zebrafish disrupted ocular morphogenesis, highlighting developmental interdependence. In human trabecular meshwork cells, WT1 acted as a transcriptional repressor of MMP9, while TNF-α signaling triggered nitric oxide-dependent nuclear export of WT1, resulting in delayed MMP9 upregulation. This effect was reversible by inhibiting nuclear export or nitric oxide synthase. A patient-derived mutation in the nuclear-export region of WT1, disrupted this regulatory switch, causing abnormal MMP9 expression. These findings position WT1 as an important regulator linking developmental and inflammatory mechanisms in glaucoma pathogenesis.

anterior segment dysgenesis

Performance comparison of rapid and native barcoding methods for Oxford Nanopore sequencing of Poliovirus Viral Protein 1 (VP1) amplicons.

Accurate and timely sequencing of poliovirus is critical for global eradication efforts, particularly for molecular epidemiology based on the typing region of the genome, viral protein 1 (VP1). While Oxford Nanopore Technologies (ONT) sequencing has expanded capabilities for poliovirus surveillance, the relative performance of different ONT library preparation methods, including ligation-based (Native Barcoding) and transposase-based (Rapid Barcoding) approaches, has not been systematically evaluated. In this study, we compared rapid barcoding and native barcoding workflows for sequencing VP1 amplicons from 17 type 2 poliovirus-positive samples, each processed in triplicate. Native barcoding generated significantly more sequencing output, producing approximately 2.3-fold greater total read yield than rapid barcoding, and demonstrated higher run-to-run reproducibility (R2 = 0.979-0.998 vs. 0.847-0.929, respectively; p&#x202f;<&#x202f;0.001). In addition, native barcoding generated 80% of the total yield achieved by rapid barcoding within approximately 7&#x202f;h, whereas rapid barcoding required approximately 40&#x202f;h to reach the same output. Despite these differences, both methods produced identical VP1 consensus sequences across all samples, with comparable read quality (median per-base Q-scores of approximately Q17-Q18). Rapid barcoding provided substantial practical advantages, reducing hands-on library preparation time (55 vs. 200&#x202f;min) and per-sample cost ($12.82 vs. $16.54), while simplifying workflow and reducing technical complexity. These findings indicate that sequencing yield may not be a determinant of downstream analytical outcomes for poliovirus VP1 ONT sequencing. Rapid barcoding therefore represents a cost-effective and efficient approach for routine poliovirus surveillance, whereas native barcoding remains advantageous in applications requiring rapid data generation or maximal sequencing depth.

Poliovirus

Integrated multi-omics analyses identify an RAS-SLC11A2-associated molecular framework linking iron metabolism with PCOS-related cardiometabolic risk.

INTRODUCTION: PCOS is a common endocrine disorder with elevated cardiometabolic risk, yet the role of the renin-angiotensin system (RAS)-iron metabolism axis in this comorbidity remains unclear. We explored its underlying mechanisms and evaluated the therapeutic potential of gentiopicroside. METHODS: Integrated multi-omics analyses combining transcriptomics, single-cell RNA sequencing, Mendelian randomization, machine learning, molecular docking, and in vitro functional assays were performed to identify shared molecular pathways and therapeutic targets across PCOS, hypertension, NAFLD, and T2DM. RESULTS: SLC11A2 was consistently dysregulated in PCOS transcriptomic datasets, and associated with iron metabolism, inflammatory response and oxidative stress pathways. Genetic analyses validated RAS-related regulation in hypertension susceptibility and revealed shared genetic architecture between PCOS and cardiometabolic traits. Network and single-cell analyses characterized SLC11A2-associated molecular patterns in disease-relevant cell types; machine learning identified disease-classifying molecular signatures. Gentiopicroside alleviated inflammatory and oxidative stress phenotypes, including reduced IL-6 expression and reactive oxygen species accumulation. CONCLUSION: This study defines an RAS-SLC11A2 molecular framework linking iron metabolism dysregulation to PCOS-related cardiometabolic risk, elucidating the mechanisms connecting ovarian dysfunction, inflammation, oxidative stress and hypertension, and supports gentiopicroside as a promising therapeutic candidate.

Humans

Spore-forming Clostridia as overlooked determinants of microbial risk in wastewater reuse systems.

Using treated municipal wastewater for crop irrigation is a key strategy to combat drought-induced water scarcity. However, current wastewater reclamation standards systematically underestimate risks from spore-forming pathogens. As highlighted in a recent minireview by A. Mrozinski, C. Le Mar&#xe9;chal, and E. Topp in Applied and Environmental Microbiology (92:e00173-26, 2026, https://doi.org/10.1128/aem.00173-26), Clostridioides difficile and Clostridium perfringens survive conventional disinfection, persist indefinitely in agricultural soils, and harbor critical antibiotic resistance genes. To safeguard the food supply and protect public health, regulatory frameworks must shift from relying solely on standard vegetative bacterial indicators and include monitoring resilient, spore-forming pathogens.

Clostridium

Dynamics and virulence of Enterobacteriaceae reservoirs harboring blaCTX-M group 1 in community wastewater.

UNLABELLED: Extended-spectrum beta-lactamase (ESBL)-producing bacteria are ubiquitous and can cause serious infections. Here, we examined untreated community wastewater influent as a reservoir for blaCTX-M group 1 organisms and their virulence potential. Raw influent samples (n = 268) were collected from four wastewater treatment plants (WWTPs) representing dense urban populations. We observed that blaCTX-M group 1 levels were high at all WWTPs and only ~1-2 log10 lower and not correlated to common human-specific microbiome fecal markers, Lachno3 and HF183, indicating a lack of connection to human fecal inputs. Concentrations of blaCTX-M group 1 genes and markers for presumptive host organisms Escherichia coli and Klebsiella pneumoniae were influenced by travel time and season. Amplicon sequencing revealed high diversity of blaCTX-M group 1-9 genes, with 63% belonging to group 1. Selective culture and 16S rRNA gene sequencing showed blaCTX-M group 1 isolates were 26% E. coli, 26% K. pneumoniae, 40% other Enterobacteriaceae, and 8% Aeromonas. Overall, E. coli averaged 3.6E7 cells/L, with 3% of all E. coli found to contain blaCTX-M group 1. Whole-genome sequencing of blaCTX-M group 1 E. coli from wastewater revealed resistance and virulence gene profiles similar to clinical isolates and distinct from other wastewater ESBL-resistant and non-resistant E. coli. Interpretation of wastewater data needs to consider both the existence of environmental reservoirs that contain potentially pathogenic organisms and the strong influence the dynamics of the conveyance system can have on final concentrations measured at the WWTP. IMPORTANCE: The CTX-M enzyme family is highly abundant in nosocomial, community, and environmental settings and is leading to treatment of infections with carbapenem antibiotics, a last-line therapeutic option. The progressive increase of the clinically relevant blaCTX-M group 1 resistance genes in the human population warrants investigation, particularly to understand the establishment and dynamics of environmental reservoirs. This study utilized molecular and culture methods to gain insight into the possible origin, abundance, and dynamics of blaCTX-M group 1 genes in untreated wastewater influent samples. We found extremely high levels of these genes, with Escherichia coli as a major host organism that closely resembled clinical strains, suggesting they are seeded and propagate in sewer pipe systems. The significance of our research is in developing approaches to monitor antimicrobial resistance reservoirs in community wastewater, which could shed light on global burdens and potential transmission cycles and indicate increasing inputs of clinically relevant strains originating from human populations.

E. coli

Immunohistochemical evaluation of Ki-67 and GLI1 in sporadic and nevoid basal cell carcinoma syndrome-associated odontogenic keratocysts.

INTRODUCTION: Odontogenic keratocyst (OKC) is a developmental odontogenic cyst that may occur sporadically (OKCsp) or in association with nevoid basal cell carcinoma syndrome (NBCCS) (OKC-sy). NBCCS is an autosomal dominant disorder characterised by morphological abnormalities and an increased predisposition to several neoplasms, including basal cell carcinomas. Mutations in the tumour suppressor gene PTCH1 have been reported in patients with OKC and NBCCS. PTCH1 participates in a signalling cascade that culminates in the translocation of GLI transcription factors to the nucleus, thereby activating target genes involved in cell proliferation. Aberrant GLI1 expression has been associated with increased proliferation in lung adenocarcinoma and other cancers. OBJECTIVE: To compare GLI1 and Ki-67 protein expression in OKCs associated with NBCCS versus sporadic OKCs. MATERIALS AND METHODS: We included 13 OKCsp and 9 OKCsy from a children's hospital and university ... Immunohistochemistry was performed using anti-GLI1 and anti-Ki-67 to assess GLI1 expression and cell proliferation. RESULTS: No significant differences were observed in GLI1 or Ki-67 expression in the epithelial component of OKCsy versus OKCsp. A positive correlation between GLI1 and Ki-67 expression was detected in the total sample (r = 0.71, p < 0.05). CONCLUSION: The positive correlation between GLI1 and Ki-67 expression in OKCs suggests an association between SHH pathway activity and cell proliferation in both sporadic and syndromic lesions.

GLI1

Insights into specific and nonspecific butyrate-producing pathways during the in vitro fecal fermentation of butyrylated starch.

Butyrylated starch is a special type-4 resistant starch with butyrate-carrying attribute. In this study, the unique butyrate-producing capability of butyrylated starch was deeply investigated by focusing on its specific and nonspecific butyrate-producing pathways, respectively, using specially designed substrates as controls. In vitro fermentation studies revealed that butyrylated and isobutyrylated starches generated high levels of butyrate and isobutyrate, respectively, highlighting the role of butyryl group metabolism in the specificity of butyrate production. Carboxylesterase assays have demonstrated that butyryl group metabolism is primarily facilitated by carbohydrate esterases expressed in the gut microbiota. Combined with 16S rRNA sequencing and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, it was found that butyrylated starch fermentation did not significantly enhance traditional butyrate synthesis pathways but modified the balance between the butyryl-CoA:acetyl-CoA transferase and butyrate kinase pathways by altering the gut microbiota composition, specifically by upregulating the relative abundance of indicator species such as Bacteroides, the Lachnospiraceae_NK4A136_group, and Parabacteroides. These insights offer theoretical guidance for designing butyrylated starch structures and regulating intestinal health.

Starch

Acetazolamide to prevent ventilatory drive withdrawal in REM sleep apnoea: a randomised controlled trial.

BACKGROUND: Obstructive sleep apnoea (OSA) pathogenesis during rapid-eye movement (REM) sleep has been linked to dips in ventilatory drive and downstream genioglossus hypotonia. The carbonic anhydrase inhibitor acetazolamide is known to increase ventilatory drive and improve OSA severity. Therefore, we tested the effect of acetazolamide on REM-predominant OSA severity (apnoea hypopnoea index (AHI) and hypoxic burden, co-primary outcomes) and underlying physiological mechanisms (ventilatory drive, ventilation and pharyngeal muscle activity). METHODS: 11 participants with REM-predominant OSA per baseline polysomnography (REM AHI/non-REM AHI&#x2265;2) were allocated to receiving acetazolamide 500&#x2009;mg for three nights (first night at half dose) or placebo according to a randomised, crossover, double-blind design. Detailed physiological polysomnography with recording of diaphragm and genioglossus electromyography was conducted after each intervention, with a 1-week washout in between. RESULTS: As hypothesised, acetazolamide reduced AHI by 35.5% (95% CI 23.1% to 46.3%) and hypoxic burden by 35.9% (95% CI 21.1% to 48.4%) vs placebo (p<0.001), meeting the primary endpoint. Mechanistic analysis in REM revealed that, unexpectedly, acetazolamide did not mitigate dips in ventilatory drive versus placebo (first decile (+0.1 (-1.0 to 1.3) L/min, p=0.8). Rather, acetazolamide reduced collapsibility (increased ventilation at eupneic drive: +1.4 (1.2 to 1.8) L/min) and raised muscle responsiveness (ventilation vs drive slope: +32 (25 to 41) %ventilation/drive, p<0.001; genioglossus versus drive slope: +0.33 (0.13 to 0.54) %max/(L/min), p=0.001). CONCLUSIONS: Acetazolamide modestly improved REM OSA, with meaningful improvements in upper airway physiology, but failed to mitigate the dips in ventilatory drive responsible for REM OSA. TRIAL REGISTRATION NUMBER: NCT05589792.

Humans

Genomic epidemiology of extended-spectrum beta-lactamase-producing Escherichia coli across humans, poultry and wastewater sectors in Douala, Cameroon.

BACKGROUND: The global health threat of antimicrobial resistance involves the human, animal and environmental sectors. Data from Cameroon are scarce. OBJECTIVES: This study aimed to define extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-Ec) rates and associated risk factors across the three sectors in Douala, Cameroon, and to define molecular characteristics of isolates. METHODS: From June 2022 to May 2023, we collected blood cultures from hospitalized patients, rectal swabs from healthy pregnant women, caeca from broiler chickens and environmental wastewater. Samples were screened for ESBL-Ec using CHROMAgar&#x2122; ESBL and cefotaxime-supplemented Tryptone Bile X-glucuronide agar. Antimicrobial susceptibility testing was performed by disk diffusion following EUCAST guidelines. Whole-genome sequencing was carried out using Illumina technology. RESULTS: Of 628 samples, 374 yielded ESBL-Ec. Prevalence was 54.6% (131/240) in pregnant women, 70.4% (169/240) in chickens and 93.1% (67/72) in wastewater. The proportion of ESBL-Ec among E. coli-positive-blood cultures was 9.2% (7/76). Multi-family household living was independently associated with ESBL-Ec carriage among pregnant women (adjusted odds ratio&#x200a;=&#x200a;1.7, 95% CI 1.0-3.1, P&#x200a;=&#x200a;0.03). High co-resistance (>70%) was observed for tetracycline, ciprofloxacin and trimethoprim/sulfamethoxazole. Sequencing of 32 isolates revealed 45 distinct resistance genes, including blaCTX-M-15 (n&#x200a;=&#x200a;13, 40.6%), blaCTX-M-55 (n&#x200a;=&#x200a;11, 34.4%) and last-resort antibiotic resistance genes mcr-1 and bla OXA-181. High-risk sequence types included ST131 (pregnant women) and ST10 (chickens). Notably, ST48 was shared between pregnant women and chickens, and ST155 between pregnant women and wastewater. CONCLUSION: Cross-sectoral ESBL-Ec in Douala exhibits high genomic diversity and alarming resistance. The occurrence of last-resort genes requires immediate One Health surveillance and coordinated interventions.

Journal Article

Metabolomics and genomics reveal high diversity and concentrations of cyanopeptides during a Microcystis bloom.

Cyanobacterial blooms are an immense global problem that release complex mixtures of poorly characterized biologically active cyanopeptides into freshwater. In this study, metabolomics and genomics were used to assess the diversity and concentrations of cyanopeptides during a dense Microcystis bloom during the late summer of 2023 in Lake Champlain, a large transboundary lake situated between Canada and the United States. Despite the relatively low genetic diversity of the bloom determined by 16S rRNA metabarcoding, 151 cyanopeptides were detected by non-targeted metabolomics. This represents the most recorded cyanopeptides from a single lake plankton bloom event to date. Fifty-two cyanopeptides were previously reported and 99 represent putative new structures. Standards from the microcystin, cyanopeptolin, microginin, and anabaenopeptin groups were used to either quantify or approximate respective cyanopeptide concentrations over the sampling period. Cyanopeptolins were the most diverse (n&#x202f;=&#x202f;68) cyanopeptides and the second most abundant, reaching 12,892&#x202f;&#x3bc;g/L. Microginins were the second most diverse (n&#x202f;=&#x202f;24) and reached the highest concentrations (18,262&#x202f;&#x3bc;g/L). Anabaenopeptins were the third most diverse (n&#x202f;=&#x202f;17) cyanopeptides, reaching 4,818&#x202f;&#x3bc;g/L. Only 8 microcystins were detected, reaching 4,935&#x202f;&#x3bc;g/L, where MC-LR was the dominant congener. Target cyanopeptide biosynthesis genes for microcystins (mcyE), cyanopeptolins (mcnC), anabaenopeptins (apnD), microviridins (mdnC), and aeruginosins (aerA) were also quantified using digital droplet PCR (ddPCR). The gene copy numbers for mcyE, mcnC, and apnD were highly correlated with their corresponding cyanopeptide concentrations. Overall, the studied Microcystis bloom produced a very diverse cyanopeptide mixture with high cyanopeptide concentrations including non-microcystin groups.

Microcystis

Heat stress in cereal crops: reproductive development and grain filling.

Increasingly frequent extreme heat events threaten cereal production and food security under a changing climate. The reproductive-to-grain formation continuum of cereals is particularly vulnerable to elevated temperatures, as heat stress disrupts developmental processes from inflorescence formation and fertilization to grain filling and quality establishment. These disruptions reduce reproductive success, impair yield formation, and compromise grain quality. A comprehensive understanding of the developmental, physiological, molecular, and genetic basis of cereal heat tolerance is therefore essential for developing climate-adapted crops. This review summarizes recent advances in understanding heat stress during cereal reproduction and grain filling across major cereal crops. We first discuss how heat stress affects sequential developmental processes, including inflorescence development, gametophyte development, flowering and pollination, fertilization, and grain filling. We then integrate emerging evidence on cross-cutting mechanisms that connect stage-specific heat responses, focusing on hormonal and redox homeostasis, carbohydrate metabolism and source-sink coordination, proteostasis and endomembrane organization, and genome stability and multilayered gene regulation. Finally, we summarize the genetic basis of cereal heat tolerance by highlighting genetic determinants, favorable alleles, and their potential applications in breeding. We further discuss current bottlenecks and future opportunities for breeding heat-tolerant cereals.

Cereals