We aimed to investigate the neuroprotective effect of Echinacoside (ECH) extracted from Cistanche tubulosa (Schenk) Wight in a mouse model of LPS-induced neuroinflammation and associated memory impairment, and the potential role of the microbiota-gut-brain axis (MGBA) in this process. Intraperitoneal injection of LPS in mice can induce inflammation, causing learning and memory impairment, and it can also affect the balance of the intestinal flora. The Morris water maze (MWM) experiment, immunohistochemistry, immunofluorescence chemistry, Nissl staining, and 16S rRNA gene sequencing of the mice intestinal flora were performed for the study. The results of the MWM experiment showed that mice treated with ECH were able to find the platform faster compared to the model group, with shorter distances moved than the C. tubulosa (Schenk) Wight extract (CTE) group, and they had more platform crossings. Immunofluorescence staining of brain cortex and hippocampal tissues showed that ECH could attenuate LPS-induced neuronal damage and reduce the expression levels of Ionized calcium-binding adapter molecule 1 (Iba-1) positive cells and the Tumor Necrosis Factor-alpha (TNF-α). 16S rRNA gene sequencing of mice intestinal flora revealed that ECH exerted beneficial effects by reshaping the structure of the intestinal flora. Our findings suggest that ECH may be beneficial for alleviating neuroinflammation-related cognitive impairments, providing theoretical support for a new neuro-psycho-pharmacological approach to MGBA-related diseases through restoring intestinal flora homeostasis.
Cell culture-based manufacturing platforms, already well-established for human influenza vaccines, are increasingly being adopted in the veterinary field as a powerful alternative to traditional embryonated hen's eggs, providing improved scalability and safety. In this study, we established a serum-free suspension culture process using Madin-Darby canine kidney (MDCK) cells for the efficient production of swine influenza virus (SIV). To optimize SIV production, we investigated multiple customized serum-free media in shaking flask cultures and selected an optimal formulation that supported efficient viral production. When this optimized medium was applied to a bioreactor culture, it supported robust cell growth, achieving a maximum viable cell density of 3.8 × 106 cells/mL prior to infection. Subsequent direct SIV infection experiments, conducted without media exchange in both shaking flask and bioreactor cultures, consistently yielded high and stable virus titers reaching a maximum log2 titer of 8.0, thus confirming the excellent scalability and reproducibility of the process. Moreover, the test trivalent vaccine developed in this study using the bioreactor-produced SIV antigen triggered high hemagglutination inhibition (HI) antibody titers and robust geometric mean titers (GMT) in animal models, thereby demonstrating superior immunogenicity to egg-based commercial vaccines. Taken together, these findings suggest that MDCK cell-based suspension culture platform may provide a scalable, high-yield, and reliable framework for the modern manufacturing of cell-based SIV vaccines.
Mechanical washing is an essential practice for reducing microbial contamination on fresh produce, yet the physiological adaptation of bacteria that persist after washing remains poorly understood. Here, we investigated the adaptive responses of lettuce-associated Escherichia coli ATCC25922 that remained attached after mechanical washing and evaluated the effects of fermented navy bean extract (FBE) and a PCC13-62-derived synthetic peptide (MFP-1). Saline washing detached only 25.1±3.9% of the attached bacterial population as the wash-removed population (WRP), while the majority of cells remained as a surface-retained population (SRP). Compared with the WRP, the SRP exhibited markedly higher survival following ampicillin treatment, accompanied by coordinated upregulation of stress-response genes (rpoS, dnaK, and dps), adhesion (csgD), and multidrug efflux (marA, acrA, acrB, and tolC) genes. In contrast, washing with FBE or MFP-1 at 200 μg/mL significantly increased recovery of the WRP to 80.8±5.4% without affecting bacterial viability, while suppressing expression of these stress-response, adhesion, and multidrug efflux genes in the ampicillin-resistant SRP (AMPR-SRP), restoring ampicillin susceptibility, and thereby reducing AMPR-SRP survival following ampicillin treatment to 2.4-2.8 log CFU/mL. These findings indicate that bacteria remaining attached after washing is associated with enhanced antibiotic resistance and concerted transcriptional activation of a proposed rpoS-centered regulatory network. FBE and MFP-1 effectively restored antibiotic susceptibility associated with transcriptional suppression of genes involved in this adaptive response, highlighting their potential as functional washing additives for improving the microbial safety of fresh produce.
Polyketides are among the most structurally diverse and therapeutically important classes of natural products, serving as antibiotics, anticancer agents, agrochemicals, and industrial pigments. Their structural complexity and limited natural availability have driven the development of microbial biosynthetic platforms as scalable and sustainable alternatives to traditional extraction or chemical synthesis. Yarrowia lipolytica, a non-conventional and metabolically versatile yeast, has emerged as a promising alternative chassis for polyketide biomanufacturing, owing to its streamlined central metabolism, high acetyl-CoA availability, and exceptional physiological robustness. Recent advances in metabolic engineering and synthetic biology have enabled extensive rewiring of Y. lipolytica metabolism to support the high-yield production of complex, high-value polyketides. This review summarizes state-of-the-art strategies, from classical metabolic rewiring to emerging approaches such as organelle engineering and subcellular compartmentalization. We further highlight representative case studies of polyketide biosynthesis in Y. lipolytica, critically assess current limitations, and explore future directions to establish this organism as a programmable, industrially viable platform for polyketide production.
Curcumin is a hydrophobic polyphenol with diverse biological activities; however, its practical application is limited by poor water solubility and low oral bioavailability. In this study, we investigated whether TSP, a previously developed water-soluble curcumin-stevioside glycoside, exerts superior anti-colitic efficacy compared with native curcumin. In LPS-stimulated macrophages, TSP more effectively suppressed IL-6 and TNF-α production than curcumin under aqueous conditions, indicating greater anti-inflammatory activity in a physiologically relevant environment. In a dextran sulfate sodium (DSS)-induced mouse colitis model, oral administration of TSP ameliorated disease severity more effectively than native curcumin administered at an equivalent curcumin dose, as evidenced by reduced body weight loss, preservation of colon length, improved histopathological features, and restoration of intestinal barrier integrity. TSP also was associated with altered gut microbial diversity and composition relative to the DSS group, including enrichment of short-chain fatty acid (SCFA)-associated taxa, particularly Akkermansia. Consistent with these compositional changes, functional prediction analysis revealed an increased abundance of microbial genetic pathways associated with SCFA biosynthesis in the TSP-treated group. Collectively, these findings demonstrate that TSP exerts superior anti-colitic effects relative to native curcumin, likely owing to its improved aqueous solubility and the resulting enhancement of curcumin availability under physiological conditions. The protective effects of TSP appear to involve both direct suppression of inflammatory responses and microbiota-mediated support of intestinal barrier homeostasis. These results highlight TSP as a promising curcumin-based candidate for functional food or adjunct therapeutic applications in inflammatory bowel disease.
The Ministry of Food and Drug Safety (MFDS) has approved 19 probiotic strains for use as functional food ingredients. Although the characteristics of individual strains have been previously reported, a comprehensive evaluation of all 19 MFDS-approved probiotic strains under a unified experimental framework has not yet been conducted. Therefore, this study systematically assessed the safety, probiotic properties, and immunomodulatory activity of the 19 MFDS-approved strains. Cytotoxicity, bile salt hydrolase (BSH) activity, D-lactate production, tolerance to simulated gastrointestinal tract (GIT) conditions, adhesion capacity, and immunomodulatory activity were evaluated. All strains showed no cytotoxicity toward Caco-2 cells. BSH activity was detected in 14 strains, whereas D-lactate production (1.14-28.88 mM) was observed only in Lactobacillaceae strains. The strains exhibited a broad range of GIT tolerance, with survival rates ranging from 23.55% to 95.58%. Lactobacillus gasseri, Bifidobacterium animalis subsp. lactis, and Bifidobacterium breve showed high survival rates (>80%), whereas Bifidobacterium bifidum and Streptococcus thermophilus exhibited relatively low tolerance (<40%). Adhesion capacity was generally similar among strains (59.84~87.82%), although B. bifidum showed the highest adhesion rate (87.82%). In contrast, Enterococcus faecium and Bifidobacterium longum subsp. longum exhibited relatively low adhesion capacities. Furthermore, 14 strains modulated immune responses in LPS-stimulated RAW 264.7 cells by regulating TNF-α and IL-6 secretion. Collectively, these findings demonstrate the overall safety and strain-specific functional properties of the 19 MFDS-approved probiotic strains and provide fundamental information for selecting suitable candidates for targeted probiotic applications.
Particulate matter (PM) acts as an environmental trigger for inflammatory airway diseases. This study investigated whether oral administration of Lacticaseibacillus paracasei ATG-E1 could therapeutically attenuate PM10 diesel exhaust particle (PM10D)-induced airway inflammation, and explored associated changes in inflammatory signaling, gut microbiota, and fecal metabolites. BALB/c mice were intranasally challenged with PM10D on days 0, 3, 6, and 8, and treated with ATG-E1 or dexamethasone after airway inflammation had been induced. Airway inflammation was evaluated using bronchoalveolar lavage fluid (BALF) cytology, flow cytometry, histopathology, enzyme-linked immunosorbent assay, reverse transcription quantitative polymerase chain reaction, and immunoblotting. Lung transcriptomics, cecal 16S rRNA profiling, and fecal metabolomics were performed, and antitussive and expectorant activities were assessed using ammonia-induced cough and phenol red secretion assays. ATG-E1 reduced inflammatory cell infiltration and neutrophilia in BALF, decreased collagen deposition, and lowered levels of pro-inflammatory mediators in BALF and lung tissue. ATG-E1 attenuated PM10D-activated IκBα and ERK phosphorylation, whereas JNK and p38 phosphorylation were not significantly altered by PM10D under the present experimental conditions. ATG-E1 also reduced caspase-1 and interleukin-1α expression. RNA sequencing revealed a broad downregulation of cytokine-cytokine receptor interaction signaling. ATG-E1 treatment was associated with gut microbiome remodeling, including enrichment of Enterorhabdus and Butyricicoccus, and altered fecal metabolite profiles were characterized by increased branched-chain fatty acids and decreased branched-chain amino acids. Functionally, ATG-E1 reduced cough frequency and increased tracheal phenol red output. Overall, L. paracasei ATG-E1 alleviated PM10D-induced airway inflammation and respiratory symptoms, in association with pulmonary immunomodulation and microbiome-associated fecal metabolite remodeling.
In this study, we identified and characterized yeast strains isolated from commercially available Korean rice wine, Kooksoondang Yetnal (KY), Haechang (HC), Yangchon Ureongii (YU), and Cheongju Sinseonju (CS) makgeolli products. ITS sequence analysis identified all the yeast isolates as Saccharomyces cerevisiae. Most makgeolli isolates exhibited better growth at 15°C than the reference strain S. cerevisiae S288C. Ploidy and whole-genome sequencing analyses of six representative strains revealed that all strains possessed diploid genomes. Phylogenetic analysis based on genome sequences indicated that all makgeolli strains clustered with the Asian-origin sake/ragi lineage. HC-CAU28, KY-CAU1, KY-CAU18, and YU-CAU13 were closely related to the Japanese sake strain K7, whereas CS-CAU12 and CS-CAU26 shared a common ancestor with the Chinese industrial bioethanol strain YJSH1 and Indonesian ragi strain Y9. Compared to S288C, the makgeolli isolates displayed similar volatile flavor profiles but produced higher levels of several flavor compounds, including acetoin, diacetyl, and benzaldehyde, consistent with higher expression of the corresponding biosynthetic genes. Notably, HC-CAU28, KY-CAU1, KY-CAU18, and YU-CAU13 did not produce a clove-like flavor 4-vinylguaiacol (4-VG), reflecting the presence of a nonsense mutation in their FDC1 genes encoding ferulic acid decarboxylase involved in conversion of ferulic acid to 4-VG. The 4-VG production activity of the fdc1 mutant strains was recovered by introducing FDC1 overexpression vectors except YU-CAU13. These findings on flavor production capacity of commercial makgeolli yeast strains, based on genomic information and validated with genetic manipulation, would provide a foundation for developing yeast starters tailored for rice wine with optimized sensory and functional properties.
Biosurfactants from lactic acid bacteria are attractive as safe, multifunctional ingredients for food and cosmetic applications, yet many remain only partially characterized. An olive-derived strain was identified as Lactiplantibacillus plantarum J2K-1229 by 16S rRNA gene and genome-based phylogeny. Grown in rapeseed oil-containing medium, it secreted extracellular material with surface/interfacial activity, and its cell-free supernatant emulsified diverse plant oils (emulsification index after 24 h, 26.67-41.33%). A purified biosurfactant fraction gave carbohydrate- and lipid-positive, ninhydrin-negative thin-layer chromatography and Fourier transform infrared bands of a hydroxylated, ester- and carboxylic acid-containing lipid. Gas chromatography, NMR, and HPAEC-PAD indicated a complex, lipid-dominant mixture with major oleic and palmitic acids, NMR signals consistent with co-extracted phenyllactic acid-type metabolites, and fructose as the only detected monosaccharide. Genome mining revealed glucosyltransferases for glucose-based glycolipids but no fructosyltransferase, suggesting that the detected fructose may represent co-extracted free fructose, possibly released as a glucansucrase by-product. The preparation inhibited Candida albicans in disk diffusion assays and was non-cytotoxic to RAW 264.7 macrophages and HaCaT keratinocytes up to 200 ppm. In lipopolysaccharide-stimulated macrophages it suppressed nitric oxide production (88.07% at 200 ppm) and inducible nitric oxide synthase expression, and in cytokine-stimulated keratinocytes it reduced TARC, MDC, and RANTES expression. Overall, this olive-derived L. plantarum produces a multicomponent, glycolipid-containing biosurfactant preparation with emulsifying, antifungal, and anti-inflammatory activities suited to cosmetic and personal-care applications.
Age-related loss of muscle strength is closely associated with frailty, reduced mobility, and loss of independence. In this study, we investigated the clinical and metabolomic features of deer antler extract fermented with Latilactobacillus curvatus HY7602. A 12-week randomized, double-blind, placebo-controlled trial was conducted in adults with reduced muscle function to evaluate the effects of daily intake of the fermented extract on muscle-related outcomes and functional performance. In parallel, exploratory untargeted LC-MS/MS-based metabolomic profiling was performed to examine biochemical changes during fermentation at three stages: extract (E), HY7602-supplemented extract (L), and fermented extract (F). After 12 weeks, the fermented deer antler extract group showed improvements in selected muscle-related outcomes compared with the placebo group, including bilateral and unilateral hand grip strength, right quadriceps strength, and Short Physical Performance Battery chair-stand performance. Metabolomic profiling revealed stage-dependent differences among the three preparation stages. Principal component analysis showed distinct clustering of E, L, and F, with the largest separation observed between E and F. Trajectory analysis suggested progressive changes in polyamine-related metabolites, amino acid derivatives, and γ-glutamyl peptides. Pathway analysis further indicated coordinated differences in nitrogen and amine metabolism, polyamine metabolism, glutathione-related metabolism, nucleotide metabolism, and central carbon metabolism. HY7602-fermented deer antler extract may support selected strength-related outcomes in adults with reduced muscle function. Metabolomic profiling characterized the fermented product and provides a foundation for future mechanistic studies.
Actinomycetes are a diverse group of microorganisms that play essential roles in environmental processes and drug discovery, particularly through the production of bioactive secondary metabolites. In Indonesia, most actinomycetes have been isolated predominantly from soil; however, the country encompasses a wide range of underexplored ecosystems, including karst ecosystems, geothermal areas, mangroves, marine organisms, and plant-associated environments. This review analyzes the biodiversity of actinomycetes across different environments in this island nation by constructing a phylogenetic tree based on 152 strains with available 16S rRNA gene sequences. This analysis revealed a broad distribution of actinomycete taxa, with the majority belonging to the genus Streptomyces. A total of 44 actinomycete-derived natural products, comprising both structurally elucidated and putatively identified compounds, have been reported in previous studies. These findings indicate that natural products from Indonesian actinomycetes remain underexplored compared with global reports. Furthermore, this review identified that molecular-level identification remains limited and suggests future studies to increase DNA sequencing efforts and deposit the resulting data in public databases to enhance taxonomic precision and facilitate future research in natural product discovery and phylogenetics.
Probiotics are increasingly recognized for their capacity to modulate gut microbiota, regulate microbial metabolic activity, and influence host immune responses, thereby contributing to the maintenance of immune homeostasis and overall health. In this study, we assessed the efficacy and safety of heat-treated Lactiplantibacillus plantarum LM1004 (HT-LM1004) in a randomized, placebo-controlled clinical trial and explored its mechanisms of action in a simulated human intestinal microbiome ecosystem. After 8 weeks of supplementation, we observed significantly enhanced natural killer (NK) cell activity with a concurrent improvement in white blood cell (WBC) counts relative to the placebo group, suggesting an overall enhancement of the host's primary immune defense baseline within the normal physiological range. Mechanistic investigations within the simulated human intestinal microbiome ecosystem demonstrated that HT-LM1004 increased microbial species diversity in the ascending colon (AC), followed by elevated richness in the transverse colon (TC) and descending colon (DC) at the End and Post time points, suggesting selective enrichment of low-abundance beneficial bacterial taxa. Metabolomics analyses indicated compartment-specific changes, especially within bile acid metabolism pathways, while non-bile acid metabolites were predominantly enriched in the DC. Short-chain fatty acid (SCFA) profiling also revealed distinct, time-dependent changes across the different gut compartments. Collectively, these results indicate that L. plantarum LM1004 boosts NK cell activity in humans by enriching low-abundance beneficial bacteria and modulating their metabolic products, underscoring its promise as a microbiome-based functional food and preventative option to support immune health.
Sarcopenia, characterized by an age-related progressive decline in skeletal muscle mass and strength, is emerging as a major public health concern in aging societies. Despite growing insights into sarcopenia pathophysiology, effective and targeted therapeutic strategies for preventing or treating age-related muscle loss remain limited. Here, we aimed to examine the effects of Weissella cibaria Wikim0187, a probiotic strain isolated from kimchi, on age-related sarcopenia. Male C57BL/6J mice aged 18 months received oral administration of Wikim0187 (1 × 109 CFU per mouse) for 4 months. Wikim0187 supplementation induced significant increases in gastrocnemius muscle mass and quadriceps muscle mass, absolute grip strength, and mean muscle fiber cross-sectional area. At the molecular level, MuRF-1 and Atrogin-1 expression was substantially reduced, whereas that of MyoD and Myogenin was markedly elevated, particularly in the quadriceps muscle. Western blot analysis confirmed a reduction in Atrogin-1 protein levels and an increase in phosphorylated Akt. In addition, gut microbiota analysis revealed significant alterations in microbial composition, with positive correlations between enriched bacterial taxa and improved clinical parameters. Taken together, these findings support the therapeutic potential of Wikim0187 as a safe and effective intervention for the prevention and treatment of sarcopenia in elderly populations.
Chronic Fatigue Syndrome (CFS) significantly impairs health-related quality of life in working-age populations, leading many individuals to use nutritional supplements for fatigue management. YC-1101, an enzymatically derived deer velvet extract, has demonstrated anti-fatigue potential in preclinical studies; however, clinical evidence in humans remains limited. This study aimed to evaluate the efficacy and safety of YC-1101 in adults with CFS. In an 8-week randomized controlled trial, 100 patients with CFS were assigned to either the YC-1101 or the placebo group. Subjective fatigue was assessed at baseline, at an interim point, and at the end of the intervention. Fatigue-related blood biomarkers and cardiorespiratory endurance were measured at baseline and postintervention. Compared with placebo, YC-1101 significantly improved Factor 1 (general and physical fatigue) of the Multidimensional Fatigue Inventory (MFI) at weeks 4 and 8, with a significant group-by-time interaction (p = 0.002), and improved the MFI items "I feel tired" and "I get tired easily" at both time points (group-by-time interaction p = 0.014 for each). YC-1101 also significantly improved fatigue-related motivation and functional interference on the Fatigue Severity Scale (FSS) at weeks 4 and 8, with significant group-by-time interactions (p = 0.040). After excluding outliers, the exercise distance to exhaustion was significantly greater in the YC-1101 group (p = 0.031), and lactate levels showed a significant group-by-time interaction at week 8 (p = 0.049). No significant differences in the safety outcomes were observed between the groups, and no adverse events were reported. Daily supplementation with YC-1101 for 8 weeks was safe, enhanced fatigue resistance, and improved exercise performance in adults with CFS, supporting its potential use in treating chronic fatigue.
In the context of the research on food ingredients, "novel microorganisms (NMs)" refers to microorganisms without a documented history of safe consumption. The utilization of these novel microorganism-derived ingredients is expanding rapidly within the food and nutrition sectors, and such ingredients are broadly classified into three categories, live microorganisms, non-viable bacteria, and purified metabolites, each characterized by distinct risk profiles and unique regulatory requirements. Despite their growing prevalence, a globally harmonized protocol for safety assessment is currently lacking, leading individual nations to implement disparate safety frameworks within their respective regulatory systems. Consequently, this review aimed to provide a scientific foundation for the standardization of safety criteria by performing a comparative analysis of established guidelines from the European Union (EFSA), United States (FDA), Canada (Health Canada), Brazil (ANVISA), Thailand (Thai FDA), India (FSSAI), Japan (FSCJ), and Australia/New Zealand (FSANZ). Our analysis identified several universal safety parameters for live NMs, including hemolytic activity, antimicrobial resistance (AMR), toxigenic potential, the production of antimicrobial substances, metabolic profiling, and toxicological assessment. While toxicological evaluation, the production of antimicrobial substances, and the absence of live NMs were the consensus criteria for the safety evaluation of non-viable bacteria and purified microbial metabolites, an allergenicity evaluation is additionally required for purified microbial metabolites. Based on our analysis, this review proposed safety standards for novel microbial food ingredients including live microorganisms, non-viable bacteria, and purified metabolites by synthesizing these diverse regulatory landscapes.
Intestinal organoids have emerged as a transformative model system in virology, bridging the gap between conventional cell lines and animal models by recapitulating the complex cellular diversity, three-dimensional architecture, and key functions of the human intestinal epithelium. This review highlights how this technology has enabled groundbreaking studies of enteric viruses, including the successful cultivation of previously uncultivable human norovirus, and has provided critical insights into the infection mechanisms of rotavirus, enterovirus A71, and Severe Acute Respiratory Syndrome Coronavirus 2. We discuss how emerging technologies, such as co-culture systems for host-microbiome interactions, vascularization techniques, and CRISPR/Cas9 gene editing, are being integrated with organoids to create more physiologically relevant microphysiological systems. Despite challenges related to immune component integration and model standardization, intestinal organoids offer a promising platform for elucidating virus-host interactions, advancing antiviral drug screening, and promoting personalized infectious disease research.
Vibrio parahaemolyticus harboring the pVA1 plasmid (VpAHPND) causes acute hepatopancreatic necrosis disease (AHPND), a major threat to global shrimp aquaculture. Although bacteriophage (phage)-based biocontrol has emerged as a promising alternative to antimicrobial agents for controlling VpAHPND, most studies have focused on disease prevention in culturing shrimp rather than post-harvest applications. In this study, a KVP40-like jumbo phage, designated vB_VpM-pA3B5, was isolated and characterized, and its biocontrol potential was evaluated in both VpAHPND-contaminated shrimp products and shrimp bioassay. Phage vB_VpM-pA3B5 exhibited a broad host range, infecting globally distributed VpAHPND strains, an AHPND-causing V. campbellii strain, and three additional Vibrio species. The phage demonstrated strong lytic activity, efficient replication, and high environmental stability. Genome analysis revealed a 243,570-bp linear dsDNA genome encoding 382 predicted ORFs and 28 tRNAs, with no virulence or antimicrobial resistance genes detected. Comparative genomic analysis indicated high synteny with the Schizotequatrovirus phages KVP40 and PVA8 and identified a unique tail fiber protein (ORF115) that may contribute to its broad host range. In VpAHPND-contaminated shrimp products, the phage efficiently reduced bacterial loads and actively replicated during storage. In the shrimp bioassay, although cumulative mortality was not reduced, phage-treated shrimp exhibited alleviated hepatopancreatic lesions and lower pirA gene loads than the VpAHPND-challenged group. These findings highlight the potential of phage vB_VpM-pA3B5 as a biocontrol agent for mitigating AHPND-associated risks in shrimp aquaculture and reducing the dissemination of VpAHPND through shrimp products.
Rhamnolipids are attractive biosurfactants for enhanced oil recovery, but the commonly used producing strains may raise biosafety concerns. In this study, a rhamnolipid-producing isolate, designated Bacillus sp. DQ-4, was obtained from oily sludge and cultivated in a glucose-based fermentation medium. The purified product, DQ-Rha, was characterized by TLC, FTIR, MALDI-TOF MS, and 1D/2D NMR (1H, 13C, 1H-1H COSY, 1H-13C HSQC, and HMBC). The combined spectroscopic results were consistent with a rhamnolipid structure, and no obvious conflicting signals were detected. DQ-Rha reduced the surface tension to 33.4 mN/m, and the DQ-4 supernatant showed an oil-spreading diameter of 89.3 mm and an emulsification index of 72.3% against diesel. In oil-displacement-related evaluations, DQ-Rha gave an oil-washing efficiency of 54.62%. In etched micromodel experiments, the total recovery factor reached 60.06%, which was comparable to that of commercial rhamnolipid (59.53%). In core flooding experiments at 85°C, injection of DQ-Rha after primary water flooding further increased the recovery factor by 10.56%, again showing performance comparable to commercial rhamnolipid. Acute oral toxicity testing in ICR mice showed no mortality or obvious toxic symptoms at 5040.6 mg/kg, and the acute oral LD50 was greater than 5000 mg/kg under the test conditions. These results suggested that DQ-Rha was a rhamnolipid biosurfactant with favorable oil-displacement-related performance and low acute oral toxicity.
The enzymatic regulation of phenylpropanoid metabolism is a critical determinant of flavonoid biosynthesis in medicinal plants. Sageretia thea is valued for its pharmacological properties associated with flavonoid production; however, the molecular mechanisms governing pathway entry remain poorly understood. In this study, we identified and functionally characterized a novel 4-coumarate:CoA ligase (St4CL1) from S. thea. Phylogenetic analysis classified St4CL1 as a Class II isoform, a group typically associated with flavonoid biosynthesis, and multiple sequence alignment revealed the presence of highly conserved functional motifs, including the AMP-binding and catalytic domains. Recombinant St4CL1, heterologously expressed in Escherichia coli, exhibited a strong preference for Mg2+ and optimal catalytic activity at pH 7.0-8.0 and 35°C. Substrate specificity analysis revealed that St4CL1 exhibited the highest relative activity toward p-coumaric acid, supporting its role in directing carbon flux into the flavonoid biosynthetic pathway. Homology modeling and molecular docking revealed a conserved substrate-binding pocket within the inter-domain cleft, and p-coumaric acid was the substrate to form a salt-bridge contact at the carboxylate-binding site, providing a structural rationale consistent with its preferred turnover. Collectively, these findings provide the first molecular evidence of the phenylpropanoid entry step in S. thea and identify St4CL1 as a promising enzymatic target for metabolic engineering to enhance flavonoid production.
This study aimed to investigate the therapeutic efficacy and underlying mechanisms of Qingxuan Zhike Granules (QXZKG) in pediatric Mycoplasma pneumoniae pneumonia (MPP), with a specific focus on its roles in modulating gut microbiota and promoting intestinal repair via the "gut-lung axis". A BALB/c mouse model of MPP was established for in-vivo experiments. Evaluations included the disease activity index (DAI), histopathological assessment of lung and intestinal tissues (H&E staining), pro-inflammatory factor levels (PCR), intestinal tight junction protein expression (Western blot), gut microbiota composition (16S rDNA sequencing), and serum lipopolysaccharide (LPS) levels. For in-vitro experiments, a Caco-2/RAW264.7 co-culture system was used to assess the effects of drug-containing serum on cell viability, apoptosis, inflammatory factor production, and barrier protein expression. QXZKG administration dose-dependently improved the DAI and body weight loss in MPP mice. It significantly alleviated pathological damage in both lung and intestinal tissues, reduced the expression of pro-inflammatory factors, and up-regulated the levels of intestinal tight junction proteins. Concurrently, QXZKG decreased serum LPS concentrations, restored gut microbiota diversity, and modulated its composition by increasing probiotic abundance and reducing opportunistic pathogens. In-vitro experiments confirmed that QXZKG-containing serum enhanced cell viability, inhibited apoptosis, reduced LPS levels, and up-regulated barrier protein expression. QXZKG is associated with modulation of the gut microbiota, enhancement of intestinal barrier function, and suppression of systemic inflammation, suggesting a potential involvement of the "gut-lung axis". These findings provide experimental evidence for the expanded clinical application of QXZKG.
