Search Results (1,115)

Biofilm formation represents a key survival strategy employed by Vibrio cholerae to adapt to the complex intestinal environment of the host. While most previous studies on V. cholerae biofilms have focused on genetic regulation and monospecies cultures, its ability to form dual-species biofilms with other intestinal pathogens is still poorly understood. In this study, using samples from both cholera patients and healthy individuals, Fusobacterium nucleatum was identified as a bacterium capable of co-aggregating with V. cholerae. Untargeted metabolomic analysis revealed that F. nucleatum-derived metabolites, specifically 6-hypoxanthine, enhance biofilm formation in V. cholerae. Further validation confirmed that these F. nucleatum-derived metabolites upregulate the biofilm-associated regulatory gene vpsT. In an adult mouse model, co-infection with F. nucleatum and V. cholerae significantly enhanced the intestinal adaptability of V. cholerae compared to infection with V. cholerae alone. Together, these findings elucidate the mechanism enabling the co-infection of F. nucleatum and V. cholerae in the host intestine, thereby shedding new light on how other pathogenic bacteria can assist in V. cholerae infection. Full article

Gastric cancer (GC) is the fifth most common cancer worldwide, with the highest incidence in East Asia. Although H. pylori is a well-known risk factor, carcinogenesis can occur independently of H. pylori infection, and approximately 43% of adults carry H. pylori as part of their native microbiota. This study aimed to identify potential oral and gastric microbial markers across different histological stages of GC in both H. pylori-positive and -negative patients. Buccal swabs and gastric mucosa samples were collected from patients with intestinal metaplasia, low-grade dysplasia, high-grade dysplasia, early GC, or advanced GC. Total DNA was extracted, and 16S rRNA gene amplicon sequencing was performed. Microbiome diversity generally remained stable across histological stages, with no directional shifts in community structure. Differential abundance analysis revealed higher relative abundances of Anaerostipes, Phocaeicola, and Collinsella in the gastric antrum of cancerous samples. Anaerostipes and Phocaeicola are typically enriched in the intestinal microbiota but are rarely observed in the stomach, suggesting their potential ecological and pathological relevance in gastric carcinogenesis. In H. pylori-negative patients, however, a different stage-associated abundance pattern was observed, in which Faecalibacterium, a genus predominantly associated with the intestinal environment, was less abundant in advanced gastric cancer samples than in earlier histological stages within the gastric body. These findings suggest that microbial changes during gastric cancer progression may follow different trajectories depending on H. pylori infection status. In oral samples, Haemophilus and Prevotella were more abundant in intestinal metaplasia than in low-grade dysplasia, and network analysis indicated links between Neisseria and Filifactor at oral and gastric sites. However, as the study population was limited to a single country and ethnicity, the applicability of these microbial markers should be carefully considered. Full article

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a multifaceted systemic condition, with the mechanisms linking intrahepatic lesions to systemic complications remaining a significant enigma in the field. This review posits that extracellular vesicles (EVs) serve as pivotal mediators facilitating communication between the liver and the entire organism. Within the hepatic environment, lipotoxic hepatocyte-derived EVs modulate macrophage populations and stellate cells, thereby promoting inflammatory and fibrotic processes. Systemically, the liver engages in bidirectional communication with adipose tissue, the intestinal tract, the cardiovascular system, and the pancreas via EVs, thus orchestrating metabolic homeostasis. Furthermore, we critically evaluate non-invasive diagnostic strategies and emerging therapies, including both natural and engineered EVs, based on EV-based interventions. We highlight the substantial potential and current challenges associated with achieving precision medicine in MASLD through targeted modulation of this specific communication network. Full article

Antibiotic feeding in shrimp farming is an optional practice conducted with the aim of preventing and controlling bacterial diseases. However, the administration of antibiotics can disrupt the microbiota of both shrimp and surrounding environment, potentially compromising host health. Given the limited effective antibiotic options in aquaculture, it is crucial to evaluate the effects of florfenicol (FF) on the intestinal health of shrimp and the associated microbial communities. This study first investigated the impact of FF on the intestinal structure of Penaeus vannamei over two feeding durations (5 and 10 days), each followed by a 10-day basal diet recovery period. Simultaneously, variations in microbial communities and antibiotic resistance genes (ARGs) in both the intestine and rearing water were explored. The results showed that intestinal damage was aggravated with the extension of FF duration and gradually recovered after FF withdrawal. Significant changes in microbial composition and β-diversity were observed in both the rearing water and intestine following FF feeding. Extending the FF treatment to 10 days led to a reduced abundance of Rhodobacteraceae and an increased abundance of Flavobacteriaceae and Vibrionaceae in the intestine after 10 days of feeding the basic diet, which may pose a potential risk to shrimp health. Based on correlation analysis of ARGs, microbial communities and pathogenic bacteria, we speculated that rearing water may serve as a reservoir for ARGs dissemination compared to the shrimp intestine. These findings are of great importance for assessing the impact of administration duration under the FF therapeutic dose and highlight the potential risks associated with its overuse in shrimp farming. Full article

In marine aquaculture environments, microplastics (MPs) and cadmium (Cd) are widespread contaminants that may jointly affect host–microbe interactions. Here, we examined the combined effects of MPs (5 mg/L) and Cd (5 μg/L) on the intestinal microbial community of pearl oysters after a 48 h exposure, followed by a 5-day recovery period. Gut microbiota dynamics were characterized using 16S rRNA gene sequencing. Alpha diversity did not vary significantly, whereas beta diversity showed marked alterations in community composition among the different exposure treatments. LEfSe analysis revealed distinct microbial biomarkers and putative pathogens under each treatment: Sulfitobacter in the MPs-alone group; Vibrio and Candidatus_Megaira in the Cd-alone group; and Tenacibaculum, Roseibacillus, and Enterovibrio across different co-exposure and recovery groups. A brief recovery period partially decreased the abundance of certain pathogens (e.g., Vibrio), yet some taxa (e.g., Enterovibrio and Tenacibaculum) remained enriched. These results indicate that exposure to MPs and Cd, whether alone or in combination, disrupts gut microbial homeostasis in pearl oysters by reshaping community structure and promoting the proliferation of potential pathogens, with some disturbances persisting after exposure ceases. Generally, our findings will aid evaluation of the ecological risks of combined pollutants in marine aquaculture systems. Full article

Gut microbial community assembly involves a critical bioenergetic trade-off, yet the gut microbes with roles in influencing intestinal metabolic homeostasis remain poorly understood in pelagic ecosystems. A central unresolved question is whether microbiome structure is primarily governed by stochastic geographic drift or by deterministic metabolic filters imposed by diet. Here, we test the metabolic release hypothesis, which posits that access to high-quality prey physiologically “releases” the host from obligate dependence on diverse fermentative symbionts. By integrating δ15N analysis with 16S rRNA metabarcoding in the anchoveta from the South Pacific waters (Engraulis ringens), we reveal a profound, diet-induced restructuring of the gut ecosystem. We demonstrate that trophic ascent triggers a deterministic collapse in microbial alpha diversity (rs = −0.683), driven by the near-complete competitive exclusion of fermentative bacteria (rs = −0.874) and the resulting dominance of a specialized proteolytic core. Mechanistically, the bioavailability of zooplankton-derived protein favors efficient endogenous hydrolysis over costly microbial fermentation, rendering functional redundancy obsolete. Crucially, we find that while metabolic function converges, taxonomic identity remains geographically structured (r = 0.532), suggesting that local environments supply the specific taxa to fulfill universal metabolic roles. These findings establish a link between δ15N as a nutritional physiology proxy of anchoveta and its gut for microbial functional state, bridging the gap between nutritional physiology and ecosystem modeling to better inform the management of global forage fish stocks. Full article

The annual nitrogen loss from the livestock production sector poses a significant threat to the global natural environment. Therefore, it is urgent to focus on improving the nutrient utilization efficiency of ruminants and promoting the sustainable development of livestock production. Twelve 60-day-old Ganxi goats with similar body weights were selected and randomly assigned to two dietary treatment groups. The control group was fed only a basal diet, while the treatment group was supplemented with 32 mg/d of Swollenin. The experiment lasted for 30 days. At the end of the experimental period, the goats were euthanized, and their intestinal contents were collected, rapidly frozen, and stored at −80 °C for subsequent metagenomic and metabolomic analyses. In the Swollenin group, we observed changes in gut microbiota structure and significantly enhanced feed conversion efficiency compared to the control group. Notably, genera such as Bacteroides, Ruminococcus, and Bifidobacterium exhibited significantly higher abundance. Following Swollenin supplementation, the gene abundance associated with the secondary bile acid biosynthesis pathway in the intestinal tract of young goats was significantly higher. The levels of primary bile acids (BAs), including taurocholic acid, glycocholic acid, taurochenodeoxycholic acid, and glycochenodeoxycholic acid, were significantly lower, while the concentrations of secondary BAs such as ursodeoxycholic acid and deoxycholic acid were significantly higher. The abundance of nitrogen-fixing and nitrogen-assimilating genes in the gut of young goats in the Swollenin group was significantly higher. Furthermore, co-occurrence network analysis revealed a strong correlation between bile acid metabolism and nitrogen metabolism pathways. These results suggest that nutritional regulation may serve as a preventive strategy to optimize the symbiotic development of animals and their gut microbiota, ultimately improving nitrogen utilization. Full article

Microplastic pollution is a growing global environmental and public health concern, driven by the increasing production and use of plastics. Due to their ubiquitous presence in the environment, humans and animals may be exposed to micro- and nanoplastics via several possible routes. For micro- and nanoplastics, the development of standardized and validated methods remains an important area of progress to support human health risk assessments. In order to monitor micro/nanoplastics’ occurrence in organisms and the environment, it is necessary to develop accurate and reliable methods to quantify and characterize micro/nanoplastics from various biological and environmental matrices. In this study, an analytical, multi-platform approach was established to characterize and quantify polystyrene nanoplastics in biological samples through a combination of sample pre-concentration, asymmetric flow field-flow fractionation, ultraviolet–visible light, dynamic light scattering detectors and pyrolysis–gas chromatography–mass spectroscopy. Several digestion methods on various rodent tissues were tested and modified, and these led to the development of tissue-specific protocols to maximize yield. These digestion protocols were then combined with a new method of concentrating and retaining plastics to prevent the loss of submicron particles. For identification and quantification, known amounts of polystyrene nanoplastics were spiked into rodent tissues (intestine, kidney and liver). This was followed up by a mouse in vivo study consisting of a single dose of PS-NPs, followed by tissue collection, digestion and analysis. Polystyrene particles were detected in the liver and kidney, but not reliably in the intestinal tissues. Full article

Extraintestinal pathogenic Escherichia coli (ExPEC) is a major cause of infections of the urinary tract, the bloodstream, and other non-intestinal sites in humans. ExPEC often resists the bactericidal action of human immune defenses including complement, antimicrobial peptides, antibodies, and cell-mediated killing. This review provides an overview of the main host defense strategies, and the mechanisms and molecules ExPEC engages to resist these human immune responses. Surface-exposed polysaccharides, outer membrane proteins, cytotoxins, and proteases are all part of the bacterial arsenal of defenses that can neutralize many of the host’s immune defenses. These factors work in concert to enable ExPEC to survive and thrive in extraintestinal environments of the human body. Full article

Metabolic-dysfunction-associated fatty liver disease (MAFLD) is a chronic liver disease characterized by abnormal lipid metabolism. The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor involved in regulating multiple physiological processes. Recent studies have demonstrated that AHR exerts a multifaceted regulatory role in liver diseases by integrating metabolic and immune signaling pathways; however, the specific role of AHR in MAFLD is not clear. In our work, a rat model of MAFLD was established by feeding wild-type (WT) and AHR knockout (AHR^−/−) rats with a high-fat, high-fructose, and high-cholesterol diet (HFHFrHCD) for 10 weeks, and then the liver injury markers, lipid-related biochemical indices and liver histopathology were examined to elucidate the effect of AHR on MAFLD progression. We discovered that AHR deficiency can elevate plasma transaminase levels, increase hepatic triglyceride (TG) and total cholesterol (TC), and exacerbate insulin resistance (IR) under an overnutrition environment. Subsequently, liver transcriptome and RT-qPCR were performed to investigate the underlying mechanism, which revealed that the hepatic bile acid synthesis was inhibited because of lower Cytochrome P450 Family 7 Subfamily A Member 1 (CYP7A1) expression in the liver when AHR was knockout. Additionally, intestinal flora dysbiosis occurred in AHR^−/− rats fed with HFHFrHCD, which might also contribute to the hepatic cholesterol accumulation. Taken together, our results suggested that AHR might play an important role in regulating cholesterol metabolism by inhibiting bile acid synthesis and breaking the steady state of the gut microbiota during the MAFLD progression. Full article

In this study, dextran-based hydrogels were synthesized in dimethyl sulfoxide via free-radical polymerization with three structurally different crosslinking agents: divinyl benzene (DVB), diethylene glycol diacrylate (DEGDA), and 4,4′-di(methacryloylamino)azobenzene (DMAAazoB). Their morphology, swelling ability, mechanical properties, and potential for controlled release of the model substance (uracil) were examined, with the results showing that the chemical structure and chain length of the crosslinking agents significantly influence the structural and functional properties of hydrogels. Hydrogels crosslinked with DMAAazoB showed the highest swelling ability at pH 3 and pH 6 (2552 and 1696%, respectively), associated with protonation effects and sponge-like morphology, while simultaneously showing the lowest mechanical strength (20 and 47 MPa). In vitro simulations of gastrointestinal digestion showed that uracil was not released in the gastric phase, while in the intestinal environment, the release was significant, especially in Dex-DMAAzoB hydrogels (88.52%). The absence of azoreductases in the simulated system indicates that the release of the drug in real conditions would likely be even more pronounced. The Dex-DAAazoB hydrogel exhibited a slight antibacterial effect, producing inhibition zones of 8 and 7 mm against Escherichia coli ATCC 8739 and Staphylococcus epidermidis ATCC 12228, respectively. In contrast, the remaining hydrogel formulations showed no detectable antibacterial activity toward either bacterial strain, indicating their microbiological inertness and supporting their suitability as carrier matrices for antitumor drug delivery in colorectal cancer therapy. The obtained results confirm that azo-crosslinked dextran hydrogels, with an optimized amount of crosslinking agent, are promising carriers for the targeted and controlled delivery of antitumor drugs to the colorectal region. Full article

An important microbial enzymatic pathway in the gut is choline/phosphatidylcholine degradation in which intestinal microbes utilize dietary choline to produce TMA via the choline utilization cluster polypeptide C (CutC) enzyme, a member of the glycyl radical enzyme family. Our goal in this theoretical work was to study the reaction mechanism and elucidate how the enzyme environment (steric and electronic) modulates the reaction path. Dissecting the effect of the enzyme environment on the reaction mechanism and shedding light on how steric and electronic effects affect the reaction path is an insightful and significant contribution of this work. Our theoretical results suggest that the final product of enzyme catalysis might be carbinolamine and not TMA and acetaldehyde. In addition, we found out that Glu₄₉₁ plays the role of a base in this reaction (a disputed fact) by temporarily abstracting a proton from the hydroxylic group of choline sometime during the reaction—with the proton transfer being critical for the reaction to proceed to completion. We also found that the choice of computational protocol not only alters the reaction energetics but can change the reaction path by creating new intermediates and transition states or eliminating existing ones. Full article

Minthostachys verticillata (Griseb.) Epling, commonly known as peperina, is an aromatic species endemic to Argentina and traditionally used for gastrointestinal ailments. Despite its extensive folkloric use and inclusion in the Argentine Pharmacopoeia, its aqueous extract (the most commonly consumed preparation) has been described in terms of major phytochemical groups, and, currently, no studies have investigated its effects on key intestinal epithelial mechanisms. This plant is also employed in the production of beverages and herbal blends, and its massive consumption highlights the importance of its scientific study. Here, the aqueous extract of M. verticillata was characterized by liquid chromatography–tandem mass spectrometry, leading to the identification of fourteen polyphenolic compounds. In intestinal cell models, the extract displayed high IC₅₀ values, supporting its safety, and exhibited concentration-dependent bioactivity. In HT-29 cells, it modulated NF-κB activation induced by TNF-α and reduced LPS-stimulated IL-8 production. Pretreatment of Caco-2 monolayers prevented the decrease in transepithelial electrical resistance, increased FITC–dextran permeability, and nitric oxide production triggered by an inflammatory cocktail. Additionally, the extract inhibited HT-29 cell migration. These results demonstrate that M. verticillata aqueous extract exerts anti-inflammatory, barrier-protective, and anti-migratory effects in vitro, providing novel insights into how its polyphenolic composition may underlie these biological activities, supporting its traditional use and potential applications in intestinal health. Full article

This study aimed to develop a dietary fiber-rich Antarctic krill composite shrimp surimi gel (AKSG) and to investigate the improvement effects of high protein (HP), high protein and dietary fiber (HPDF), and high dietary fiber (HDF) diet interventions on constipation behaviors and gut microbiota of mice. The results showed that the HPDF group significantly improved defecation in constipated mice, enhanced gastrointestinal peristalsis, and exhibited the most obvious effect on improving the colonic structure. The gut microbial analysis showed that the HPDF group increased the relative abundance of beneficial bacteria and improved the intestinal microbial environment of constipated mice. In addition, all groups effectively regulated the secretion of intestinal neurotransmitters. Inulin significantly increased the fecal water content by binding to water molecules, thus softening feces. Meanwhile, the addition of an appropriate amount of protein could further absorb water in the intestinal tract and relieve constipation. In conclusion, dietary fiber-rich AKSG might be a promising nutritious functional food for constipation relief. Full article

Chronic kidney disease (CKD) is estimated to affect 843.6 million people, accounting for more than 10% of the world’s population, making it a serious public health issue. Dietary therapy is important for suppressing CKD progression risk factors such as hypertension. Fruits granola (FGR), which is rich in dietary fiber, including β-glucan and polyphenols, is expected to contribute to improving the intestinal environment and providing anti-inflammatory effects. We previously reported that FGR consumption improves blood pressure and the intestinal environment in hemodialysis patients. However, the safety and efficacy of FGR for patients with moderate CKD remain unclear. Therefore, we examined the effects of FGR by replacing the breakfast of 24 patients with moderate CKD at least 5 days per week over a total of 2 months. Patients with moderate CKD who were attending outpatient appointments at the Department of Nephrology at Juntendo University Hospital and whose condition was stable were included. Patients with cancer or poor nutritional status were excluded from this study. The results revealed lower systolic blood pressure, low-density lipoprotein cholesterol (LDL-C) levels, and LDL-C/HDL-C ratios after FGR intake. Furthermore, N-acetyl-β-D-glucosaminidase (NAG), a marker of renal tubular damage, was also reduced. Regarding the intestinal environment, improved bowel movements and stool quality were observed. Based on the results of this FGR intervention study, consuming dietary fiber, which is often deficient in moderate CKD patients, may have contributed to reducing risks for cardiovascular disease and urinary tubular dysfunction through FGR intake. Full article