Search Results (8,224)

This study investigated the impact of green tea addition on microbial community dynamics during Daqu fermentation, a critical process in traditional baijiu production. Four Daqu variants (0%, 10%, 20%, 30% tea) were analyzed across six fermentation periods using 16S rRNA/ITS sequencing, coupled with STR, TDR, Sloan neutral model, and phylogenetic analyses. Results showed time-dependent increases in bacterial/fungal richness, with 30% tea maximizing species richness. Tea delayed bacterial shifts until day 15 but accelerated fungal reconstruction from day 6, expanding the temporal response window. While stochastic processes dominated initial assembly (77–94% bacteria, 88–99% fungi), deterministic processes intensified with tea concentration, particularly in fungi (1% → 12%). Tea increased bacterial dispersal limitation and reduced phylogenetic conservatism of endogenous factors. This work proposed a framework for rationally engineering fermentation ecosystems by decoding evolutionary-ecological rules of microbial assembly. It revealed how plant-derived additives can strategically adjust niche partitioning and ancestral constraints to reprogram microbiome functionality. These findings provided a theoretical foundation in practical strategies for optimizing industrial baijiu production through targeted ecological interventions. Full article

The gut microbiome is essential for gut health, immune regulation, and metabolism, but pathogenic bacteria like Enterococcus and Streptococcus can disrupt these processes, increasing infection risk after colorectal surgery. Prior studies show that intravenous antibiotics and surgical bowel preparation (SBP, including mechanical preparation with oral antibiotics) significantly disrupt the gut microbiota, potentially delaying postoperative recovery. However, the effects of surgical indication (e.g., diagnosis) and operation type on gut microbiome composition and function remain unclear. This study examines how SBP, resectional and non-resectional surgery, and underlying diagnoses shape the postoperative gut microbiome and microbial recovery. Methods: Fecal samples were collected from patients undergoing colonoscopy (n = 30), non-resectional (ventral mesh rectopexy, transanal surgery; n = 25), or resectional surgery with primary anastomosis (n = 26) at baseline, intraoperatively, and on postoperative days (POD) 10, 30, and 180. Microbial diversity was assessed through 16S rRNA sequencing, and short-chain fatty acid (SCFA) levels were measured to evaluate functional changes. Results: Alpha diversity (Shannon indices) decreased across all groups, recovering by POD10 in colonoscopy patients and by POD180 in non-resectional and resectional cohorts. Beta diversity (community composition) also returned to baseline by POD10 in colonoscopy patients and POD180 in non-resectional patients, but the resectional cohort did not fully recover (p < 0.001). Both surgical cohorts showed substantial losses of commensal bacteria through POD30, with notable increases in Streptococcus in resectional patients (p < 0.0001) and Enterococcus in both surgical cohorts (p < 0.0001). Functionally, only the resectional cohort experienced significant reductions in SCFA levels (p < 0.015) relative to baseline levels. Diagnosis minimally influenced long-term microbiota recovery, although cancer patients tended to have more stable microbiomes compared to patients with diverticulitis. Conclusions: These findings indicate that perioperative factors, especially surgical resection and SBP, significantly impact gut microbial recovery, with pathogenic bacteria persisting up to 6 months post-surgery. Full article

Background/Objectives: Medium- and long-chain triacylglycerol (MLCT) and 2′-fucosyllactose (2′-FL) are functional ingredients abundant in human milk; however, their effects on small intestinal development and health remain largely unknown, and no research has explored their potential combined effects. Methods: In this study, growing C57BL/6 mice (3 weeks old) were fed diets without or with 2.5 g/100 g of MLCT, 2′-FL, or the combination (MLCT + 2′-FL; 5:1) for 21 days. Body weight, major organ indices, small intestinal morphology-related indicators (small intestinal length, villus height, crypt depth, villus height/crypt depth (V/C) ratio, and epithelial cell proliferation), and intestinal barrier function markers (goblet cell and Paneth cell count, protein expression of ZO-1 and occludin, and levels of sIgA and LPS) were measured. Results: In addition to the shared promotion of epithelial cell proliferation, MLCT intervention raised villus height and crypt depth, while 2′-FL intervention elevated Paneth cell count and sIgA levels. Notably, MLCT + 2′-FL intervention offered additional advantages (increasing the V/C ratio, goblet cell count, and expression of ZO-1 and occludin) without affecting crypt depth. 16S rRNA sequencing analysis of cecal contents revealed that all three interventions mainly affected beta diversity rather than alpha diversity, and enriched differentially abundant bacterial taxa: Erysipelotrichaceae, Faecalibaculum, UBA1819, and Faecalitalea in the MLCT group; Enterobacteriaceae, Escherichia, and Allobaculum in the 2′-FL group; Bifidobacterium, Romboutsia, Clostridia, and several other bacterial taxa in the MLCT + 2′-FL group. Conclusions: These results indicate that MLCT and 2′-FL interventions alone appear to provide different benefits for small intestinal development, and their combination may confer more comprehensive advantages. Full article

Growth stage is a key factor influencing the composition and richness of the porcine gut microbiota. The stage-specific alterations in gut microbiota of indigenous Chinese pig breeds and cultivated breeds remain to be elucidated. This study conducted 16S rRNA sequencing analysis on fecal microbiota from Dahe black pigs across distinct growth stages. Samples included lactating sows, suckling piglets, weaned piglets, pigs weighing 50–100 kg, pigs weighing 120–150 kg, and pigs weighing > 200 kg. The results indicated that Escherichia shigella (12.4% vs. 16.2%), Lactobacillus (5.9% vs. 6.3%), and Rikenellaceae RC9 gut group (3.9% vs. 4.2%) were dominant genera shared between lactating sows and suckling piglets. The relative abundance of Eubacterium brachy group was significantly higher in lactating sows, whereas Flavonifractor was significantly lower compared to suckling piglets (p < 0.05). Compared to pigs weighing > 120 kg, lactating sows exhibited 22 differentially abundant genera, including Escherichia shigella, Cloacibacillus, Fusobacterium, Faecalibacterium, and Prevotella (p < 0.05). In suckling piglets, Firmicutes and Bacteroidota constituted 47.4% and 27.3% of the microbiota, respectively. Their relative abundance increased with body weight, reaching 52.6% and 33.3% in pigs weighing > 200 kg. Proteobacteria decreased from 17.3% in suckling piglets to 2.0% in >200 kg pigs. Spirochaetota declined from 2.5% in suckling piglets to 0.9% in weaned piglets and then increased to 6.9% in >200 kg pigs. Lactobacillus peaked at 15.7% in weaned piglets, while Escherichia shigella reached its maximum (16.2%) in suckling piglets, both gradually declining thereafter. Streptococcus abundance remained relatively stable (1.1% in suckling piglets; 4.5% in weaned piglets). Prevotellaceae NK3B31 group registered 2.9% in suckling piglets, increased to 7.1% in weaned piglets, and then declined to 2.6% in >200 kg pigs. Mitsuokella, Bilophila, Succinivibrio, Romboutsia, and Desulfovibrio were identified as the top five genera discriminating suckling and weaned piglets. Similarly, Lachnospiraceae XPB1014 group, Clostridium sensu stricto 1, Turicibacter, Quinella, and p 1088 a5 gut group were key discriminators between weaned piglets and 50–100 kg pigs. These identified microbial taxa represent potential candidate targets for modulating the developmental timing of growth phases in pigs, offering possibilities for either advancing or delaying specific physiological timepoints. Full article

Background/Objectives: HNSCC is a highly aggressive malignancy marked by the dysregulation of the cell cycle. In HPV⁻ HNSCC, mutations in the CDKN2A gene frequently result in the loss of the p16 protein, a key inhibitor of the cyclin D1/CDK4/6 complex. This loss results in unchecked G1/S phase progression. The CDK4/6 inhibitor palbociclib has shown therapeutic potential in HPV⁻ HNSCC by inducing G1 phase arrest and reducing cell viability. In this study, we investigated the molecular mechanisms by which palbociclib affects cell viability in HPV⁻ HNSCC. Methods: Four HPV⁻ HNSCC cell lines were treated with palbociclib, and RNA sequencing was performed to assess changes in gene expression. Cell viability was measured using the MTT assay. To further investigate protein localization, interactions, and function, we used immunofluorescence staining, co-immunoprecipitation, small molecule inhibitors, and siRNA-mediated knockdown. Results: We demonstrate that palbociclib downregulates survivin, a protein that plays dual roles in mitosis and apoptosis, thereby inhibiting cell proliferation. We also found that survivin is overexpressed in HPV⁻ HNSCC. Inhibiting survivin dimerization using the compound LQZ-7i significantly reduces cell viability and promotes its export from the nucleus to the cytoplasm. Additionally, we identified USP1, a deubiquitinase, as both a downstream target of CDK4/6 and a key regulator of survivin stability. Inhibiting USP1 activity or silencing its expression significantly reduces survivin levels. Conclusions: Our findings highlight survivin as a critical mediator of cell proliferation in HPV⁻ HNSCC and suggest that targeting the CDK4/6-USP1-survivin axis may offer a promising therapeutic strategy. Full article

Background: Streptomyces bacteria are prolific producers of secondary metabolites (SMs), including many antibiotics. However, most biosynthetic gene clusters (BGCs) remain silent under laboratory conditions. Global transcriptional regulators, such as AdpA, can activate these BGCs, but their roles in secondary metabolism are not fully understood. This study investigates the regulatory function of AdpA in Streptomyces venezuelae (AdpA_Sv), a fast-growing model species and natural chloramphenicol producer that encodes over 30 BGCs. Methods: We applied RNA-seq and ChIP-seq at 12 and 20 h—corresponding to vegetative and aerial hyphae stages—to profile the AdpA_Sv regulatory network. Results: AdpA_Sv influenced the expression of approximately 3000 genes, including those involved in primary metabolism, quorum sensing, sulfur metabolism, ABC transporters, and all annotated BGCs, and it bound to around 200 genomic sites. Integration of RNA-seq and ChIP-seq data identified a core regulon of 49–91 directly regulated genes, with additional effects likely mediated indirectly via other transcription factors or non-canonical binding sites. Motif analysis confirmed similarity to the canonical Streptomyces griseus AdpA-binding sequence, with a novel 5-bp 3′ extension. AdpA_Sv directly regulated several SM pathways, including chloramphenicol biosynthesis, potentially alleviating Lsr2-mediated repression. Conclusions: This study defines, for the first time, the direct AdpA regulon in S. venezuelae and establishes AdpA_Sv as a central regulator of secondary metabolism. Our findings highlight S. venezuelae as a promising chassis strain for heterologous expression and suggest strategies for activating silent BGCs in other Streptomyces species. Full article

Microorganisms with chitin-degrading capabilities play a crucial role in the biological control of crop pests and diseases as well as in the treatment of organic waste. In this study, a chitin-degrading bacterium, designated L2-2, was isolated from the intestine of Odorrana margaretae collected in Mount Emei, Sichuan, China. Based on physiological and biochemical characteristics, 16S rRNA gene sequencing, and phylogenetic analysis of 31 conserved housekeeping genes in the whole genome, strain L2-2 was identified as a member of the genus Roseateles, named Roseateles sp. L2-2. This strain is able to grow on agar medium with colloidal chitin as the sole carbon source and form clear hydrolysis zones. After optimizing fermentation conditions (including concentrations of nitrogen and carbon sources, culture time, and pH), the enzyme activity was increased to 3.46 U/mL, which was 24 times higher than the initial enzyme activity. Functional genome annotation showed that the strain contains genes encoding endochitinases of the GH18, GH23, and GH46 families, as well as genes encoding β-glucosidases of the GH1, GH2, GH3, and GH109 families, indicating its genetic basis for chitin-degrading potential. This study expands the diversity of known chitin-degrading bacteria and provides a promising microbial resource for the bioremediation of chitinous waste and sustainable pest control in agriculture. Full article

Antimicrobial therapy is a mainstay for treating reproductive diseases, including endometritis. Ceftiofur, a third-generation cephalosporin, is a common antibiotic used to treat equine bacterial endometritis. It is also routinely given empirically as an intra-uterine (IU) infusion in broodmare practice. We hypothesized that ceftiofur IU would disrupt the resident microbial community within the healthy uterus of mares. To test our hypothesis, eight university-owned mares were selected for characterization of the estrual uterine microbiome before and after IU ceftiofur. Double-guarded swabs of the estrual endometrium were taken before and 3 days after both IU saline and ceftiofur in a crossover design. Isolation of DNA from endometrial swabs was performed, followed by amplification of the V4 region of the 16S rRNA gene by Illumina Miseq sequencing to examine core bacterial communities present before and after ceftiofur. The uterine microbial composition of sham and ceftiofur-treated mares was not significantly different as measured by beta diversity. The only notable difference was a lower abundance of Christensenellaceae_R-7_group after ceftiofur (0.14 ± 1.05% vs. 2.89 ± 1.07% control; p = 0.0428). In conclusion, three-day treatment of ceftiofur did not change the microbial composition acutely within the mare uterus when sampled directly after treatment. Ceftiofur may have a long-term effect on the uterine microbiome, which may require sampling several weeks post treatment. In conclusion, ceftiofur does not change the healthy uterine microbiome acutely during estrus and but should still be used judiciously. Full article

The gut microbiota plays a crucial role in early childhood development. Dysbiosis in this community has been linked to risk of disease. The transition from an exclusive milk-based diet to complementary feeding and eventual weaning is crucial for the development and maturation of the gut microbiota. However, the impact of breastfeeding duration during the complementary feeding period (typically 6 to 24 months of age) on microbial development trajectories remains incompletely characterized. Here, we investigated whether prolonged breastfeeding during the complementary feeding window influences gut microbiota succession by comparing children who continued breastfeeding with those who were fully weaned at the same ages. We analyzed 16S rRNA gene sequencing profiles of fecal samples collected from a cohort of Peruvian children at 6, 12, 18, and 24 months of age. Samples were categorized into two groups: a complementary feeding group (BF), which received both complementary foods and breast milk, and a post-weaning group (NBF), which had stopped receiving breast milk for over 7 days. We conducted both alpha and beta diversity to assess within- and between-sample microbial variation. Relative abundances of microbial taxa at the phylum and genus levels were also quantified. The results showed a clear age-related increase in both species richness and species evenness across early childhood, while BF had more gradual changes relative to NBF. Marked differences in community composition were observed between BF and NBF children at 12, 18, and 24 months, respectively. Children who continued breastfeeding maintained a Bifidobacterium-rich, lower-diversity microbiota for a longer period, whereas weaned children at the same age exhibited accelerated microbiota development toward an adult-like profile enriched in Bacteroidota and Bacillota (formerly Firmicutes). These findings suggest that breastfeeding during the complementary feeding period exerts a significant influence on gut microbiota development through the first two years of life, which is most likely independent of complementary food. The study provides potential implications for children’s health and nutrition guidelines from a perspective of gut microbiota succession. Full article

Chelerythrine (CHE) is the main active component of Chelidonium majus L., possessing excellent antioxidant and anti-inflammatory properties. However, the protective effects of CHE against liver injury and its underlying mechanisms remain unclear. We aimed to investigate the effects of CHE on acute liver injury (ALI) and explore its underlying mechanisms. Mice were orally administered with or without CHE (15 and 30 mg/kg) treatment for 7 days, followed by a single intraperitoneal injection of acetaminophen (APAP, 350 mg/kg). After 24 h, serum, liver, and fecal samples were collected. Then, 16S rRNA gene sequencing, metabolomics, and transcriptomics approaches were employed to investigate the protective effects of CHE against ALI. Finally, we elucidated the role of CHE in restoring gut microbiota and metabolic disorders in the context of ALI. The results showed that CHE significantly inhibited ALT and AST levels (p < 0.001). Furthermore, CHE counteracted APAP-induced alterations in IL-6, IL-1β, TNF-α, MPO, MDA, H₂O₂, CAT, SOD, and GSH (p < 0.05). These results indicate that CHE possesses antioxidant properties and inhibits inflammatory factors, thereby protecting the organism from APAP-induced ALI. CHE treatment significantly altered gut microbiota composition, particularly increasing levels of the beneficial bacterium Barnesiella intestinihominis (p < 0.05). In addition, CHE reversed metabolic disturbances and inhibited oxidative and inflammatory signaling pathways. These findings suggest that CHE is a natural hepatoprotective agent that prevents ALI by modulating gut microbiota, related metabolites, oxidative stress, and inflammation. This study provides new insights into CHE as a potential therapeutic approach for ALI. Full article

Background: Irradiation (IR) targets cancer cells, but also the tumor microenvironment, including the tumor’s blood vessels. In addition to tumor endothelial cell (TEC) apoptosis, IR can lead to TEC activation, potentially increasing immune cell infiltration. However, the changes underlying the IR-induced activation of endothelial cells (ECs) are poorly understood. This study investigated dose- and time-dependent molecular and functional responses of murine and human EC lines to IR in vitro and TECs in vivo in murine tumor models of colorectal carcinoma. Methods: HUVEC, EA.hy926, and Hulec5a, as well as murine bEND.3, 2H11, and SVEC4-10 EC lines, were irradiated with single doses of 2–10 Gy. EC proliferation and survival after IR were assessed by staining all nuclei (Hoechst 33342) and dead cells (propidium iodide) every 24 h for 5 days using the Cytation 1 Cell Imaging Multi-Mode Reader. RNA sequencing analysis of HUVECs irradiated with 2 Gy and 5 Gy at 24 h and 72 h after IR was conducted, focusing on processes related to EC activation. To validate the RNA sequencing results, immunofluorescence staining for proteins related to EC activation, including Stimulator of Interferon Response cGAMP Interactor 1 (STING), Nuclear factor kappa B (NF-κβ), and Vascular cell adhesion molecule 1 (VCAM-1), was performed. To validate the in vitro results, the response of TEC in vivo was analyzed using publicly available RNA sequencing data of TECs isolated from MC38 colon carcinoma irradiated with a single dose of 15 Gy. Finally, murine CT26 colon carcinoma tumors were immunofluorescently stained for STING and NF-κβ 24 and 48 h after IR with a clinically relevant fractionated regimen of 5 × 5 Gy. Results: Doses of 2, 4, 6, 8, and 10 Gy led to a dose-dependent decrease in proliferation and increased death of ECs. RNA sequencing analysis showed that the effects on the transcriptome of HUVECs were most pronounced 72 h after IR with 5 Gy, with 1014 genes (661 down-regulated and 353 up-regulated) being significantly differentially expressed. Irradiation with 5 Gy resulted in HUVEC activation, with up-regulation of the immune system and extracellular matrix genes, such as STING1 (log₂FC = 0.81) and SELE (log₂FC = 1.09), respectively; and down-regulation of cell cycle markers. Furthermore, IR led to the up-regulation of immune response- and extracellular matrix (ECM)-associated signaling pathways, including NF-κβ signaling and ECM–receptor interaction, which was also observed in the transcriptome of irradiated murine TECs in vivo. This was confirmed at the protein level with higher expressions of the EC activation-associated proteins STING, NF-κβ, and VCAM-1 in irradiated HUVECs and irradiated TECs in vivo. Conclusions: IR induces changes in ECs and TECs, supporting their activation in dose- and time-dependent manners, potentially contributing to the anti-tumor immune response, which may potentially increase the infiltration of immune cells into the tumor and thus, improve the overall efficacy of RT, especially in combination with immune checkpoint inhibitors. Full article

The discovery of Asgard archaea has reshaped our understanding of eukaryotic origins, supporting a two-domain tree of life in which eukaryotes emerged from Archaea. Building on this revised framework, we propose the Pre-prokaryotic Organismal Lifeforms Existing Today (POLET) hypothesis, which suggests that relic pre-prokaryotic life forms—termed POLETicians—may persist in deep, anoxic, energy-limited environments. These organisms could represent a living bridge to the RNA world and other origin-of-life models, utilizing racemic oligoribonucleotides and peptides, non-enzymatic catalysis, and mineral-assisted compartmentalization. POLETicians might instead rely on radical-based redox chemistry or radiolysis for energy and maintenance. These biomolecules may be racemic or noncanonical, eluding conventional detection. New detection methods are required to determine such life. We propose generalized nanopore sequencing of any linear polymer—including mirror RNAs, mirror DNAs, or any novel genetic material—as a potential strategy to overcome chirality bias in modern sequencing technologies. These approaches, combined with chiral mass spectrometry and stereoisomer-resolved analytics, may enable the detection of molecular signatures from non-phylogenetic primitive lineages. POLETicians challenge the assumption that all life must follow familiar biochemical constraints and offer a compelling extension to our search for both ancient and extant forms of life hidden within Earth’s most extreme environments. Full article

Given that suckling lambs with immature rumen development rely on intestinal microbiota for nutrient utilization, investigating the composition and functional characteristics of their intestinal microbiota is therefore of paramount importance. In this study, 16S rRNA gene amplicon sequencing technology was adopted to characterize and analyze the diversity and composition of the jejunum, ileum and cecum bacterial communities of lambs at 0, 7 and 28 days of age, and to predict the functions of the bacterial communities. The α-diversity analysis results revealed that in the jejunum of lambs, the Chao1, PD, Simpson and Shannon indexes differed significantly among the three age groups (p < 0.05). In the ileum, Shannon and Simpson indexes of the 0-days-of-age group were slightly lower than those of the 7 (8.84% and 12.66% reductions, respectively) and 28-days-of-age groups (19.34% and 15.85% reductions, respectively) (0.05 < p < 0.10). In the cecum, Simpson and Shannon indexes differed significantly (p < 0.05) among the three age groups. At the phylum level, Firmicutes (64.68%) and Proteobacteria (21.76%) dominated the bacterial communities across all intestinal segments, with a total of 42 phyla detected. At the genus level, 19 dominant genera were identified in the jejunum. Except for Bifidobacterium, which showed no significant age-related variation (p > 0.05), the relative abundance of the remaining 18 genera changed significantly with age (p < 0.05). In the ileum, compared with the 0-days-of-age group, the Lactobacillus abundance was significantly higher in the 7- and 28-days-of-age groups (p < 0.05), while the Escherichia-Shigella, Mannheimia and Enterobacter abundances were significantly reduced (p < 0.05). In the cecum, the genera, including Blautia, Sellimonas and Ruminococcaceae UCG-014, exhibited significant age-related differences (p < 0.05), whereas other genera showed no significant variation (p > 0.05). Collectively, the bacterial community α-diversity, compositional structure and specific genus abundance in the jejunum, ileum and cecum of lambs demonstrated pronounced age-dependent variation and intestinal segment specificity patterns. This study provides a foundation for a deeper understanding of the succession patterns of the early digestive tract microbiota in lambs, and is conducive to the development of early nutrition strategies based on precise regulation of the microbiome. Full article

Background: The gut microbiota and the gut epithelium play a central role in maintaining systemic and brain homeostasis from early life. Stressful experiences during sensitive developmental windows can disrupt this balance, increasing long-term susceptibility to psychiatric disorders. However, the mechanisms through which early-life alterations in the microbiota influence brain development and function remain poorly understood. Here, the sex-specific impact of prenatal stress (PNS) on gut integrity and microbial composition in adult offspring was explored. Methods: Thirty dams were mated and randomly assigned to PNS or control. Offspring microbiota was analysed through 16S rRNA sequencing, intestinal morphology with morphometric analyses, and tight junctions using qPCR and immunofluorescence. Results: Exposure to PNS was associated with reduced intestinal surface area in males and shortened crypts in females. In both sexes, PNS caused a decrease in the expression of ZO-1, suggesting impaired gut barrier integrity. 16S rRNA sequencing revealed, furthermore, that PNS exposure was associated with a decrease in beneficial genera, including Akkermansia in males and Clostridia vadinBB60 in females, along with an increase in the pro-inflammatory genus Anaerotruncus, regardless of sex. Notably, some of these alterations were more pronounced in PNS-exposed animals that showed impaired sociability, highlighting gut microbiota inter-individual variability in the response to early-life adversity. Moreover, selected microbial changes show significant correlations with the behavioural outcomes, as well as with intestinal morphology or brain inflammatory markers. Conclusions: Together, these findings pinpoint the gut as a central player in stress vulnerability and highlight specific microbial signatures as promising biomarkers and therapeutic targets for stress-related disorders. Full article

Sea urchin aquaculture has experienced remarkable growth in recent years. However, this growth has been accompanied by increased disease prevalence. Notably, spotting disease has particularly severe impacts. In this study, we isolated the pathogen HZ-3-2 from 10 sea urchins with spotting disease, and it was identified as Vibrio splendidus through morphological observations, 16S rDNA sequencing, and whole-genome sequencing. Subsequently, experimental infection confirmed that V. splendidus (HZ-3-2) is the causative agent of spotting disease in this outbreak. The drug sensitivity confirmed the presence of drug resistance genes, such as CPR, QNRS5, and rsmA, which were identified in the genome. The tests indicated that V. splendidus was sensitive to various antibiotics, including fluoroquinolones and florfenicol. Finally, we used the transcriptome to explore the molecular response of the diseased sea urchin. Compared to the control group, a group of sea urchins immersed in a pathogen suspension with a concentration of 10⁷ CFU/mL (group M) resulted in 439 annotated differentially expressed genes. KEGG pathway analysis indicated significant activation of cholesterol metabolism and starch and sucrose metabolism in the S. intermedius. This study highlights the genes NPC1, AMY2A, and MGAM as critical regulators of energy metabolism, and cholesterol synthesis in infected sea urchins. These findings confirm V. splendidus as the bacterium responsible for spotting disease and provide valuable insights into the intestinal molecular response of S. intermedius to infection. Full article