Search PubMedSearch

SEARCH · Search PubMed

Results for “Enhancer Elements, Genetic”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

825 records · Page 13Linked to original sources

Asthma Exacerbation Risk and School Asthma Readiness.

OBJECTIVES: School-based asthma management is a key facet of child asthma care. We aimed to describe the proportion of students whose schools have child-specific components of asthma care, derive a composite metric of these components ("school asthma readiness"), and assess its association with asthma exacerbations (asthma risk) in the preceding year. METHODS: Within a nested cohort of children enrolled in a larger randomized clinical trial, we assessed the baseline proportion of children whose school had elements of necessary asthma care. We then derived a "school asthma readiness" composite and used ordinal logistic regression to model the association between number of asthma exacerbations in the preceding year and the composite, accounting for demographic, clinical, and school characteristics. RESULTS: Of 202 participants aged 5 to 13 years, most identified as Black (95%) and non-Hispanic (98%), and most participants (73%) had an emergency department visit for asthma in the year before enrollment. Most students' schools (79%) had awareness of the child's asthma diagnosis, whereas fewer had reliever medications and valved holding chambers (both 31%) and asthma care plans (7%). Asthma exacerbations in the prior year were associated with a significantly higher school asthma readiness in bivariate (odds ratio [OR], 1.44 [95% CI, 1.14-1.82]; P = .002) and multivariable analysis (OR, 1.31 [95% CI, 1.02-1.7]; P = .037). CONCLUSIONS: A minority of children attended schools that were equipped to manage asthma symptoms. More past exacerbations were associated with higher school readiness, suggesting that more work is needed to support proactive asthma care in schools.

Humans

Contrasting redox-related physiological responses associated with HaGATA23 and HaGATA36 during Orobanche cumana parasitism in sunflower (Helianthus annuus L.).

Helianthus annuus is an economically important Asteraceae species used for seed oil production and ornamental purposes, but its production is seriously affected by the root-parasitic plant Orobanche cumana. GATA transcription factors are zinc-finger DNA-binding regulators involved in plant development and stress adaptation. However, the molecular characteristics of GATA transcription factors in Helianthus annuus and their contribution to Helianthus annuus -Orobanche cumana interaction remain poorly understood. Here, 36 HaGATA members were retrieved from the Helianthus annuus genome and classified into four phylogenetic clades. Chromosomal placement, collinearity, gene structure, motif composition, and promoter elements varied among the 36 HaGATA members, indicating evolutionary conservation coupled with functional diversification. Expression analysis and RT-qPCR analyses revealed differential expression patterns among HaGATA genes under O. cumana stress, with HaGATA23 markedly downregulated and HaGATA36 strongly upregulated. Overexpression of HaGATA23 was associated with increased malondialdehyde (MDA) accumulation and unfavorable changes in antioxidant enzyme activities, whereas its silencing showed the opposite physiological tendency. In contrast, overexpression of HaGATA36 reduced malondialdehyde accumulation, increased peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) activities, while its silencing showed the reverse tendency. These results indicate that HaGATA23 and HaGATA36 are candidate genes associated with contrasting redox-related physiological responses during O. cumana stress. This work provides evidence that GATA transcription factors are associated with redox-related physiological responses in sunflower under O. cumana treatment and identifies HaGATA23 and HaGATA36 as functionally divergent candidate genes for further validation.

Helianthus

The cold case of state transition 7 (stt7) mutants of Chlamydomonas reinhardtii, solved by whole-genome sequencing.

The process of State Transitions (ST) corresponds to an STT7 kinase-driven redistribution of the transmembrane LHCII antenna proteins between Photosystem II (PSII) and Photosystem I (PSI), which results from changes in their phosphorylation state. For the past two decades, two LHCII-kinase mutants, stt7-1 and stt7-9, have been instrumental in the study of STs in Chlamydomonas reinhardtii, the former being a null mutant for the kinase but quasi-sterile in crosses, while the latter, although fertile, has a leaky phenotype. Using long-read sequencing, this study further characterized the genetic lesions of the stt7 mutant strains through whole-genome reconstruction and de novo chromosome assembly. In addition, two new stt7 null mutants were generated, one derived by crosses from the original stt7-1 and one obtained by Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-associated protein 9 (Cas9) technology. This work provides a comprehensive genomic characterization of the original stt7-1 null mutant, revealing extensive chromosomal rearrangements and high levels of aneuploidy, associated with increased cell size and meiotic dysfunction. Reassessment of their physiology and genetic backgrounds highlights the need for caution in interpreting genetic information. We thus produced more reliable null mutants for the LHCII-kinase, amenable to genetic crosses for the study of STs in a variety of genetic backgrounds.

Chlamydomonas reinhardtii

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

A case report of Xp21 contiguous gene deletion syndrome with adrenal crisis and sensorineural hearing loss: clinical highlights and management pitfalls.

OBJECTIVES: To report a rare association of Xp21 contiguous gene deletion syndrome (CGDS) featuring sensorineural hearing loss (SNHL), and to discuss the diagnostic and therapeutic challenges. CASE PRESENTATION: A male infant presented with a salt-wasting adrenal crisis consistent with X-linked adrenal hypoplasia congenita. His follow-up clinical course during childhood revealed global developmental delay and SNHL, the latter of which has been under-reported in the literature for this condition. At five years of age, the development of progressive proximal muscle weakness and markedly elevated creatine phosphokinase levels led to a diagnosis of Duchenne muscular dystrophy (DMD). The patient also exhibited pseudohypertriglyceridemia and elevated urinary glycerol, consistent with glycerol kinase deficiency. While initial exome sequencing failed to detect the genetic abnormality, subsequent chromosomal microarray analysis identified an Xp21 CGDS involving NR0B1, IL1RAPL1, DMD, and GK. Treatment of adrenal insufficiency with fludrocortisone and hydrocortisone was complicated by the higher steroid doses required for the management of DMD, resulting in exogenous Cushing syndrome and associated complications. CONCLUSIONS: This case highlights the necessity of evaluating for Xp21 CGDS in patients presenting with adrenal crisis and emphasizes the importance of multidisciplinary management to optimize outcomes in this complex pediatric endocrine disorder.

Humans

Epigenetics and In Silico Transcriptome Analysis of Pediatric Acute Myeloid Leukemia.

Pediatric acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy that accounts for about 15%-20% of childhood leukemias. Despite therapeutic advances, relapses remain common, and survival for high-risk patients is below 60%. Unlike adult AML, pediatric AML displays distinct genetic mutations, including FLT3-ITD, NPM1, KMT2A rearrangements, and core-binding factors (CBF) fusions, as well as extensive epigenetic dysregulation. Aberrant DNA methylation, histone modifications, and altered non-coding RNA expressions disrupt hematopoietic differentiation and activate oncogenic transcriptional networks. Recent advances in silico transcriptomic analysis have transformed the study of pediatric AML by integrating gene expression and epigenetic data to identify molecular drivers and regulatory networks. Computational RNA-seq pipelines and pathway analyses have highlighted key epigenetic regulators, including DNMT3A, TET2, and HDACs, as potential therapeutic targets. Multi-omics approaches combining transcriptomic, methylomic, and chromatin accessibility data are increasingly used to define biomarkers for diagnosis, prognosis, and therapeutic response. This review provides a comprehensive overview of the molecular and epigenetic landscape of pediatric AML, emphasizing the power of in silico transcriptome analysis to uncover disease mechanisms, refine patient stratification, and guide the development of precision-based epigenetic therapies aimed at improving long-term outcomes in children with AML.

Humans

Clinical Outcomes and Patient Experiences With Celiprolol Therapy in Vascular Ehlers-Danlos Syndrome: The First Non-European Cohort.

Vascular Ehlers-Danlos syndrome (vEDS) is a hereditary connective tissue disorder caused by heterozygous pathogenic variants in COL3A1. European studies have shown that celiprolol may reduce the risk of life-threatening vascular events, but outcomes in non-European populations and the therapy's psychological impact remain unclear. We conducted a retrospective cohort study of individuals aged ≥ 20 years with genetically confirmed vEDS in a single referral center in Japan between 2000 and 2024. Clinical, molecular, and treatment data were obtained from medical records, and semi-structured interviews were conducted with a subset of participants to assess patient experiences. Twenty-six patients were included. The mean age at celiprolol initiation was 36.9 years, with a mean follow-up of 96.6 months. All patients received celiprolol, and 61.5% reached the target dose (400 mg/day). One patient died of hepatic artery rupture; vascular events occurred in 11, while 14 remained event-free. No significant associations were observed between vascular event occurrence and genotype or celiprolol dose. Interviews with 11 patients revealed that celiprolol use provided emotional reassurance and promoted a more proactive approach to disease management. Celiprolol therapy may reduce fatal vascular events in vEDS and have a positive psychological impact, though nonfatal vascular complications remain frequent.

Humans

Applications of metal-organic frameworks in smart packaging for food freshness indication: a comprehensive review.

Smart packaging is extensively studied for its multifunctional capabilities in antimicrobial activity, preservation, and atmosphere modification. Recently emerged metal-organic frameworks (MOFs) freshness-indicating packaging becomes a key research direction in smart packaging owing to its distinctive functions and physicochemical properties. As multifunctional materials, the unique porous structure and tunable properties of MOFs provide a distinctive approach for developing food packaging applications dedicated to food freshness indication. Existing MOFs-based smart packaging still faces potential safety risks and technical challenges in practical applications, and there remains a lack of integrated discussion that combines synthesis strategies, packaging design, optimization, and safety assessment. This review elaborates on the application of MOFs in freshness-indicating smart packaging, focusing on diverse MOFs synthesis strategies, the formats of smart packaging, types of indicator signals, and qualitative/quantitative analytical methods. It also delves into the methodology concepts of MOFs-based smart packaging and evaluates MOFs safety in food packaging by addressing potential risks. Studies show that MOFs-based smart packaging achieves qualitative and semi-quantitative analysis of food freshness through multiple signal modalities such as visible color change, fluorescence, and photothermal effects. This review emphasizes that safe MOFs design is critically important and should comply with the overall migration limit of <10 mg/dm2 specified in Regulation (EC) No 1935/2004, lanthanide element limit of <0.05 mg/kg, and FDA threshold of 1.5 &#x3bc;g/person/day. Comprehensive safety assessment and intelligent sensing platforms will constitute pivotal directions for advancing MOFs-based smart packaging toward practical application.

Food Packaging

De Novo 2.2&#x2009;Mb 19q13.42-q13.43 Microdeletion Encompassing U2AF2: Support for a Haploinsufficiency Model.

U2 small nuclear RNA auxiliary factor 2 (U2AF2) is an essential pre-mRNA splicing factor involved in the early stages of pre-mRNA splicing. To date, multiple individuals have been reported with predominantly heterozygous missense variants presenting intellectual disability, speech and motor delays, seizures, hypotonia, and thin or hypoplastic corpus callosum. Here, we describe a patient with a de novo 2.2&#x2009;Mb interstitial deletion involving chromosome 19q13.42-q13.43, encompassing U2AF2, presenting with intellectual disability, epilepsy, corpus callosum hypoplasia, dysmorphic features, and congenital heart disease. The patient's clinical features overlap substantially with those reported in individuals harboring heterozygous U2AF2 variants, supporting haploinsufficiency as a plausible disease mechanism. To our knowledge, this represents the first postnatal report of complete U2AF2 gene deletion. In addition, this is the first detailed phenotypic characterization of a distal 19q chromosomal interstitial deletion, further delineating the clinical spectrum associated with this genomic region.

Humans

Modelling the effects of biological intervention in a dynamical gene network.

Cellular response to environmental and internal signals can be modeled by dynamical gene regulatory networks (GRN). In the literature, three main classes of gene network models can be distinguished: (1) non-quantitative (or data-based) models which do not describe the probability distribution of gene expressions; (2) quantitative models which fully describe the probability distribution of all genes co-expression; and (3) mechanistic models which allow for a causal interpretation of gene interactions. We propose two rigorous frameworks to model gene alteration in a dynamical GRN, depending on whether the network model is quantitative or mechanistic. We explain how these models can be used for design of experiment, or, if additional alteration data are available, for validation purposes or to improve the parameter estimation of the original model. We apply these methods to the Gaussian graphical model, which is quantitative but non-mechanistic, and to mechanistic models of Bayesian networks and penalized linear regression.

Gene Regulatory Networks

Branded packaging raises likelihood of cigarette purchasing in an experimental retail setting by increasing craving.

INTRODUCTION: Exposure to branded cigarette packaging in retail settings has been shown to be associated with purchasing behavior, but the mechanisms underlying this effect are unclear. This study tested whether cigarette craving and perceived health harms mediate the effect of branded packaging on cigarette purchasing in a simulated retail environment. METHODS: Young adults aged 21-34 who currently smoke cigarettes (n&#x2009;=&#x2009;290) completed an experimental shopping task in the RAND StoreLab, a life-sized replica of a convenience store. Participants were randomly assigned to one of two conditions: (1) branding present, in which branded cigarette packages were displayed; and (2) branding absent condition, in which branded elements were removed and packages were standardized in a brown-green color and uniform text. Cigarette purchases were recorded, and participants completed post-shopping measures of cigarette craving and perceived health harms. Causal effect decomposition analyses were used to assess whether these variables mediated the effect of study condition on the likelihood of purchasing cigarettes. RESULTS: Craving, but not perceived health harms, partially mediated the effect of branded packaging on cigarette purchasing. Exposure to branded packs increased the likelihood of purchasing by elevating craving (average mediated effect = 2.4%, 95% CI 0.2% - 5.0%, p&#x2009;=&#x2009;.03). CONCLUSIONS: Branded cigarette packaging appears to increase cigarette purchasing at least in part by increasing cigarette craving at point of sale. Interventions that address craving management in retail settings (e.g., just-in-time interventions, prn nicotine replacement therapy) may help mitigate the impact of branding on young adults' cigarette purchasing.

Humans

Whole-Genome Deep Learning Predicts Chemotherapy Response in Colorectal Cancer.

Chemotherapy response in colorectal cancer (CRC) exhibits significant heterogeneity, with current clinical predictors failing to capture complex genomic determinants of resistance. We developed a hybrid deep learning framework integrating convolutional neural networks (CNNs) and bidirectional long short-term memory (BiLSTM) networks to analyze whole-genome somatic mutations, evolutionary conservation, chromatin accessibility, and 3D genome architecture in 2,546 TCGA patients. An attention mechanism identified predictive genomic regions. The model achieved an AUC of 0.92 (95% CI: 0.89-0.94) in cross-validation and 0.88 (95% CI: 0.85-0.91) in independent validation, outperforming clinical models (&#x394;AUC = +0.18, p < 0.001). Key predictors included non-coding variants in TP53, KRAS, and PIK3CA regulatory regions. Triple-positive patients (mutations in all 3 regions) had significantly worse progression-free survival (HR = 4.7, p < 0.001). Our framework enables accurate chemotherapy response prediction and reveals novel non-coding resistance mechanisms, advancing precision oncology in CRC.

Humans

Influence of ovarian maturity, age, and mating status on&#xa0;the antennal responses of wild and laboratory reared Xyleborus affinis (Coleoptera: Curculionidae: Scolytinae) to ethanol.

Xyleborus affinis Eichthoff is a neotropical ambrosia beetle that, in certain regions such as the United States and Mexico, has been associated with exotic phytopathogenic fungi causing extensive tree mortality. Although studies relating its olfactory response to volatile compounds and trapping systems have been published, factors such as the insect's physiological condition, which can affect its recognition or response to odors, have not been studied. Here, we evaluated the electroantennographic (EAG) response of wild and&#xa0;laboratory reared X. affinis females to 70% ethanol, a compound known to attract these insects. The experimental design was developed to consider and compare the following conditions: (i) females collected inside and outside host-galleries, (ii) sexual maturity (with mature and immature ovaries), (iii) age (0, 1, 3, and 5&#x2009;d after emergence), and (iv) mating status (virgins and mated). Our results indicate that most of the wild females located outside the galleries were sexually mature but exhibited significantly lower EAG response than those inside the galleries. Regarding mating status, mated females exhibited significantly stronger antennal responses compared to virgins, whereas age did not affect antennal sensitivity. Finally, we provide images of the hitherto undescribed reproductive system of X. affinis females, a key element that enabled this investigation. The information generated offers a useful foundation for future studies aimed at understanding the physiological mechanisms and other critical factors related to sensory perception and reproductive condition. For example, factors that may influence the behavior and attraction of X. affinis females to host semiochemicals.

Animals

Mechanisms of Hematopoietic Stem Cell Aging and Emerging Rejuvenation Strategies.

Hematopoietic stem cell (HSCs) aging is a complex biological process driven by both cell-intrinsic alterations and extrinsic cues from the bone marrow niche. Understanding these mechanisms is critical for developing therapies against aging-related hematopoietic disorders. This review synthesizes recent advances in the molecular mechanisms underlying HSCs aging, including microenvironmental aging, genomic instability, epigenetic dysregulation, mitochondrial dysfunction, and aberrant nuclear mechanotransduction. We summarize that the functional decline of HSCs during aging drives a compensatory expansion of the phenotypically defined stem cell pool, leading to an aberrant increase in cell number. We also highlight aging-associated HSCs heterogeneity, including CD150high and P-selectin-positive subsets that enrich for myeloid-biased or functionally compromised HSCs states while emphasizing that surface phenotype alone may not fully indicate functional rejuvenation. Finally, we discuss emerging rejuvenation strategies-including targeting myeloid-biased HSCs, modulating inflammatory pathways, and implementing epigenetic or metabolic interventions-supported by cutting-edge technologies such as single-cell multi-omics, gene editing, and computational modeling. These approaches hold promise for counteracting age-related hematopoietic decline and restoring immune competence.

Humans

A polygenic risk score for peripheral artery disease and major adverse limb events.

BACKGROUND AND AIMS: Large-scale genome-wide association studies have identified common genetic variants that predict the risk of peripheral artery disease (PAD). This study assessed whether a polygenic risk score (PRS) is associated with PAD and the incidence of major adverse limb events (MALE) independent of clinical risk factors in patients with established cardiometabolic disease. METHODS: A genetic analysis was performed, pooling individual patient-level data from six TIMI trials. The association of a recently validated PAD PRS with prevalent PAD and the incidence of MALE (acute limb ischaemia, chronic limb-threatening ischaemia, major amputation, or peripheral revascularization) was assessed. RESULTS: A total of 68 816 patients were included in this analysis, with a median follow-up of 2.6 years. Of these, 5986 (8.7%) had known PAD at baseline. After adjusting for clinical risk factors, a higher PAD PRS was independently associated with a 15% greater odds of prevalent PAD (adjusted odds ratio per 1-SD: 1.15 [95% confidence interval 1.12-1.18], P < .0001), a magnitude of risk as strong as established clinical risk factors. A total of 577 patients experienced MALE during follow-up. A higher PAD PRS was associated with a 30% increased risk of MALE (adjusted hazard ratio per 1-SD: 1.30 [1.19-1.42], P < .0001). Adding the PAD PRS to clinical risk factors resulted in a statistically significant but modest improvement in discrimination (area under the curve went from 0.651 to 0.662 P < .0001). CONCLUSIONS: In a broad spectrum of patients with cardiometabolic disease, the PAD PRS is associated with an increased risk of PAD and the incidence of MALE beyond clinical risk factors; however, the improvement in discrimination was statistically significant but clinically modest.

Humans

Strategies for mosaic variant calling in brain disorders.

The human brain is a genomic mosaic, where postzygotic mutations arising from embryogenesis to senescence drive diverse neurodevelopmental and neurodegenerative diseases. Because of numerous sequencing artifacts at ultralow variant allele frequencies (VAFs), detecting these variants remains a significant analytical challenge. This review focuses on single-nucleotide variants and small indels, summarizing current strategies for aligning sampling methods, including bulk, laser capture microdissection, and single-cell genomics, with the expected clonal architecture of the brain. It emphasizes that mosaic detection sensitivity is fundamentally constrained by sequencing depth, since even the most advanced algorithms cannot identify variants not physically represented in the sequencing library. The review further recommends the selection of variant calling algorithms based on validated VAF detection performance, matching tools like MuTect2 and MosaicForecast to their optimal performance ranges. Furthermore, we discuss how multitissue sampling, as emphasized by the SMaHT project, addresses the matched-control dilemma and supports accurate variant classification via cross-tissue VAF gradients. Integrating these established pipelines with multiomics modalities, including transcriptomic and epigenetic data, could advance the field toward a functional understanding of how the somatic genome impacts human brain health and disease.

Humans

Cytonuclear conflict and reticulate evolution in the Morelloid clade (Solanum, Solanaceae): Insights from genome skimming and network Phylogenomics.

The Morelloid clade (black nightshades) is one of the most strongly supported clades within the megadiverse Solanum genus. It comprises 76 globally distributed, non-spiny herbaceous and suffrutescent species. While often erroneously considered poisonous weeds, several species are economically important as orphan crops. The clade is closely related to tomato and potato but, due to a lack of focused breeding efforts, remains a putative reservoir of genetic diversity for crop improvement. Despite this potential, we lack fundamental knowledge on the evolution of the Morelloid clade. The group includes polyploid species with unknown parental origins-likely reflecting reticulate processes such as hybridization, introgression, and associated backcrossing events. Prior analyses have been unable to disentangle these processes, leaving the mechanisms underlying reticulate evolution in the Morelloid clade poorly understood. Here, we use genome skimming to produce a well-supported maximum likelihood plastid phylogeny from complete circularized plastomes and a coalescent-based species tree from combined Angiosperms353 and conserved ortholog set nuclear markers. Our dataset, composed of previously published data and deep genome skimming from herbarium samples, spans 26 Morelloid species. To investigate phylogenetic discordance, we used a nuclear phylogenetic network, multispecies coalescent simulations, a fused rooted nuclear chloroplast tree, and quantification of nuclear gene tree concordance. We show that incongruence between nuclear and plastid trees is pervasive and cannot be explained by incomplete lineage sorting alone. Instead, our results demonstrate that events consistent with repeated chloroplast capture have shaped the reticulate evolutionary history of the clade, especially among African polyploid and Pan-American diploid lineages.

Phylogeny

A complete hlyCABD-like RTX operon marks a virulence-associated subset of trh-positive Vibrio parahaemolyticus from Hangzhou Bay, China.

Vibrio parahaemolyticus remains a major cause of seafood-associated gastroenteritis, yet routine surveillance still relies largely on the canonical hemolysin markers thermostable direct hemolysin (tdh) and tdh-related hemolysin (trh). To determine whether this framework overlooks accessory virulence determinants in trh-positive lineages, we analyzed 193&#xa0;V. parahaemolyticus isolates collected between 2022 and 2025 from clinical, environmental, and seafood-associated sources in the Hangzhou Bay region of China. Serotyping identified 45 serotypes, with O10:K4 predominating among clinical isolates. Both clinical and non-clinical populations showed open pan-genomes, although the non-clinical group carried a larger accessory gene pool. We identified a complete hlyCABD-like RTX operon in 10 trh-positive isolates with T3SS2-associated virulence backgrounds. These RTX-positive isolates were distributed across seven sequence types and three of five phylogenetic groups. This distribution was lineage-restricted but non-clonal. In the representative hybrid-assembled genome, the operon occurred within a mosaic genomic region containing additional virulence- and mobility-associated genes, indicating a composite pathogenicity island-like element. In the tested subset, RTX-positive isolates showed significantly greater hemolytic activity than RTX-negative trh-positive isolates. This significant difference was consistently observed in both plate-based and liquid assays, and within the RTX-positive subset, hlyA expression correlated with hemolytic activity, whereas the trh gene and the tlh (thermolabile hemolysin) gene did not. A complete hlyCABD-like RTX operon therefore identifies a hemolysis-associated subset of trh-positive V. parahaemolyticus and supports its further evaluation as an additional target for food safety surveillance.

Vibrio parahaemolyticus