Journal of microbiology and biotechnology最新文献

Wound healing, critical for skin recovery after surgery, trauma, and chronic damage, proceeds through inflammation, proliferation, and remodeling phases. In this study, we focused on the proliferative phase using fermentation extracts from the residuals of Adlay bran ethanol extraction and their solvent fractions. Among them, the butanol fraction exhibited the strongest antioxidant activity and significantly enhanced the proliferation of human dermal fibroblasts, as confirmed by a real-time wound closure assay. Cell cycle analysis revealed an increased proportion of cells in the S-phase and upregulation of Cyclin A1 and Cyclin B2 mRNA, indicating accelerated progression toward the G2/M phase. We then purified the butanol fraction using C18 MPLC and HPLC and identified uridine and deoxythymidine as the main components by LC-MS/MS and NMR analysis. These nucleosides derived from fermented adlay bran residues directly promote fibroblast proliferation, highlighting their potential as sustainable bioactive compounds for skin regeneration and functional ingredient development.

Recent advances in microbiome research have highlighted that age-related physiological changes are closely shaped by shifts in the gut microbial community rather than by the passage of time alone. Aging is frequently accompanied by a decline in microbial diversity and the loss of short-chain fatty acid-producing taxa, changes that weaken the intestinal barrier and contribute to the persistent low-grade inflammation described as inflammaging. These alterations intersect with immune and metabolic pathways linked to immunosenescence, cellular senescence, and mitochondrial function. In contrast, microbial ecosystems enriched with butyrate-producing and polyamine-generating species have been associated with more stable epithelial integrity, improved metabolic flexibility, and balanced immune activity. Emerging findings also indicate that the gut microbiota communicates with peripheral organs through the gut-skin, gut-muscle, and gut-brain axes, influencing tissue-specific aging processes. Evidence from animal models and human studies shows that dietary modulation, probiotics, and other microbiota-directed approaches can partially restore microbial functions relevant to aging, although responses vary considerably across individuals. Interest is also growing in postbiotic strategies, including microbial metabolites and vesicle-based components, which may offer targeted effects without requiring colonization. By integrating these mechanistic and translational insights, this review outlines how the gut microbiota contributes to aging biology and discusses the potential for microbiome-based interventions to support healthspan.

Methicillin-resistant Staphylococcus aureus (MRSA) represents a serious threat to public health due to its strong antibiotic resistance, wide dissemination, and high infection rates. Rapid identification of MRSA strains is essential for accurate diagnosis and timely treatment of related infections. In this study, we propose an analytical method for MRSA that employs a hairpin-structured locker-probe to directly regulate the trans-cleavage activity of Cas12a. This designed locker-probe connects a target-specific aptamer to an inhibitory aptamer of the CRISPR/Cas12a system. Upon binding to the specific target, the probe undergoes a conformational change that abolishes its inhibitory effect on Cas12a. As a result, the structure-switchable probe modulates Cas12a activity in a target-dependent manner. Additionally, the sensing substrate combines a "cis-cleavage trigger" and a "trans-cleavage trigger" to integrate both cis- and trans-cleavage activities of Cas12a/crRNA within a single probe. This design significantly simplifies the probe architecture while maintaining high signal amplification efficiency. The proposed method was successfully applied to detect MRSA, achieving a detection limit as low as 2.5 CFU/ml with high specificity. By exploiting the inhibitory aptamer of Cas12a as a regulatory element for MRSA analysis, this work expands the toolbox of CRISPR/Cas12a-based methodologies and offers a promising strategy for bacterial detection.

Muscle atrophy refers to the loss or wasting of muscle tissue caused by medication, aging, disease, and injury. Propionibacterium freudenreichii MJ2 (MJ2) shows anti-inflammatory and anti-obesity properties. This study aimed to determine the effects of MJ2 on dexamethasone (DEX)-induced muscle atrophy in C2C12 myoblast cell line and rats. Heat-killed P. freudenreichii MJ2 (HK-MJ2) inhibited a decrease in the diameter of DEX-treated C2C12 myotubes. Additionally, it downregulated the expression of muscle atrophy- and apoptosis-related genes (MuRF-1, Atrogin-1, and Bax/Bcl-2) in DEX-treated C2C12 cells while activating proteins (p-Akt/Akt and p-mTOR/mTOR) associated with muscle protein synthesis. Live- and HK-MJ2 treatment increased grip strength, muscle mass, and muscle fiber area in rats with DEX-induced muscle atrophy. In conclusion, both live- and HK-MJ2 increase muscle mass and muscle fiber area, resulting in the improvement of DEX-induced muscle atrophy.

Clostridioides difficile infection (CDI) is a bacterial infection of the colon that can cause diarrhea and colitis. The use of antimicrobials disrupts the intestinal microbiota, weakening colonization resistance and creating an environment in which C. difficile can establish infection. It is, therefore, necessary to identify specific bacteria that are helpful for the recovery of the intestinal microbiota in individuals with CDI. Previous studies have identified several strains that showed a negative correlation with C. difficile. Among these strains, C. hylemonae DSM 15053, which possesses the bai operon similar to Clostridium scindens, was selected. To test this hypothesis, we utilized a CDI mouse model and evaluated the inhibitory effect of C. hylemonae DSM 15053. Furthermore, to gain insights into the underlying mechanisms, we performed gut microbiota analysis. Contrary to our expectations, C. hylemonae DSM 15053 did not significantly produce SBAs. Interestingly, however, microbial diversity and richness were significantly higher in the C. hylemonae DSM 15053-treated group compared with the PBS control group. In addition, we observed a higher abundance of the genera Phocaeicola, Akkermansia, and Parabacteroides in the C. hylemonae DSM 15053 group. Moreover, metagenomic and metabolomic analyses revealed that C. hylemonae DSM 15053 mitigates CDI through a mechanism distinct from that of C. scindens KCTC 5591, which primarily functions as a regulator of bile acid metabolism.

Probiotics, including Lactiplantibacillus plantarum, have therapeutic potential to alleviate osteoporosis, which is particularly common in postmenopausal women with increasing bone fracture risk. Since live probiotics may cause adverse effects under certain conditions, such as in immunocompromised individuals, postbiotics, could be a safer alternative. In this study, we investigated whether heat-killed L. plantarum KCTC 10887BP (K-Lp, postbiotic form) has comparable therapeutic effects to live L. plantarum KCTC 10887BP (L-Lp, probiotic form) on bone loss in a mouse postmenopausal osteoporosis model. Oral administration of either L-Lp or K-Lp significantly improved bone parameters, including trabecular bone volume, thickness, and number, compared to ovariectomy (OVX) control mice. Both treatments significantly increased bone mass and bone mineral density, elevated serum procollagen 1 N-terminal propeptide levels as a marker of bone formation, and reduced the number of tartrate-resistant acid phosphatase-positive osteoclasts in femoral tissue. Furthermore, oral administration with L-LP or K-Lp increased runt-related transcription factor 2, alkaline phosphatase, and collagen type I alpha 1 chain, which are key markers for osteoblast differentiation and activation. However, no effects were observed in Sham mice. Either L-Lp or K-Lp demonstrated similar therapeutic effects against bone loss in a postmenopausal mouse model. These findings suggest that heat-killed L. plantarum KCTC 10887BP exhibited comparable effects to live bacteria in this OVX model, and that postbiotics could serve as a therapeutic alternative for osteoporotic bone loss.

Dermal extracellular matrix (ECM) deterioration is a central driver of skin aging, contributing to impaired elasticity, decreased moisturization, and uneven pigmentation. However, commonly used single-component ingredients and cell-derived bioactives provide limited coordinated cues and may therefore be insufficient to address these multifactorial processes. Here, we propose decellularized skin-derived ECM (skin ECM) as a multifunctional cosmetic ingredient through comparison with various existing cosmetic ingredients. Proteomic analysis shows that skin ECM retains diverse collagen subtypes along with glycoproteins and proteoglycans associated with dermal tensile properties and matrix regulation, more closely reflecting native dermal matrisome diversity than commercial collagen products. Skin ECM at an optimal concentration most effectively upregulates the expression of genes involved in ECM remodeling and hyaluronan-mediated hydration in human dermal fibroblasts. In comparative supplementation assay, skin ECM enhances fibroblast metabolic activity and induces the strongest expression of key ECM- and hydration-related genes among all tested ingredients. Interestingly, skin ECM reduces the expression of melanogenesis-related markers and melanin accumulation in melanoma cells under experimental conditions with α-melanocyte stimulating hormone treatment. Collectively, these findings highlight the potential of skin ECM for cosmetic applications to improve overall skin conditioning and its broader promise for anti-skin aging.

Viability PCR (v-PCR) was optimized using propidium monoazide (PMA) and Triton X-100 for the selective detection of live foodborne pathogens in this study. The colony-forming unit (CFU) method, conventionally used for detecting live foodborne pathogens, is time-consuming. Quantitative PCR (qPCR) and droplet digital PCR (ddPCR) have emerged as rapid alternatives for pathogen detection, which provide accurate detection at low bacterial concentrations. However, these methods cannot distinguish between live and dead bacteria. We investigated the optimization of v-PCR conditions using PMA concentrations (10-200 μM) and Triton X-100 concentrations (0-1%) for Salmonella enterica subsp. enterica and Cronobacter sakazakii. PMA at 100 μM effectively inhibited the amplification of dead bacteria, whereas 1% Triton X-100 enhanced PMA efficiency. The optimized v-ddPCR method successfully distinguished live from dead bacteria, although discrepancies were observed between CFU counts and ddPCR copy numbers. Triton X-100 treatment reduced these discrepancies, bringing the ddPCR copy numbers closer to CFU counts obtained from traditional culture methods. This optimized v-ddPCR protocol provides a rapid and reliable approach for detecting viable foodborne pathogens in food safety applications, that offers enhanced sensitivity compared with conventional culture-based methods.

Acne vulgaris is a prevalent inflammatory skin disorder mediated by Cutibacterium acnes, a key etiological factor. In this study, the anti-acne properties of the ethyl acetate fraction of Quercus salicina Blume (QsB-EE) against C. acnes were investigated. The QsB-EE fraction was separated into subfractions (E1-E6) using preparative HPLC. Antimicrobial and anti-virulence activities were evaluated via bacterial growth, biofilm, and lipase activity assays. Virulence gene expression was assessed using qRT-PCR, and bioactive compounds were identified by LC-MS/MS. The QsB-EE demonstrated significant antimicrobial (MIC 125 μg/ml) and strong anti-virulence effects. The E1 fraction was the most potent, exhibiting the lowest MIC (16 μg/ml), highest biofilm inhibition (86.19% at 1,000 μg/ml), and highest lipase inhibition (93.72% at 10 μg/ml). In addition, mechanistic studies confirmed that E1 significantly downregulated the expression of key virulence genes: ppa0149 (biofilm), gehA (lipase), and hyl (hyaluronidase). LC-MS/MS identified (+)-catechin as the major compound in E1, alongside kaempferol and quercetin in E5. Although further in vivo studies are warranted to evaluate the therapeutic efficacy, our findings suggest that QsB-EE possesses promising anti-acne potential by targeting C. acnes virulence factors through the active compounds concentrated in the E1 fraction.

Hemolytic uremic syndrome (HUS), a fatal complication of Shiga toxin-producing Escherichia coli (STEC) infection, is classically characterized by acute renal failure, but frequently accompanied by central nervous system (CNS) dysfunction. Because the CNS is normally protected by the blood-brain barrier (BBB), the toxin-mediated BBB injury is considered to be a major cause of neurologic sequelae in STEC infection. Here, we delineate how Shiga toxin type 1a (Stx1a) and Shiga toxin type 2a (Stx2a) compromise BBB-like endothelial barrier integrity with the human brain microvascular endothelial cell line hCMEC/D3 as an in vitro model, complemented by an endothelial-astroglial co-culture system. Stx1a/Stx2a exposure induced the MAPK pathway and ER stress, triggering caspase-mediated apoptosis and pro-inflammatory cytokines expression. Coincidentally, permeability across tight junctions was impaired, with junctional protein loss and increased paracellular permeability. Pharmacologic inhibition of caspases prevented cytotoxicity and tight junction loss, indicating a role for the apoptotic process in barrier breach. In co-cultures with transwell, human astrocytes (A172) demonstrated caspase activity and cytokine induction even without direct exposure to toxins, indicating endothelial injury-release paracrine activity in the propagation of BBB injury. Reactive oxygen species (ROS) also accumulated distal to toxin exposure and aligned with apoptotic and barrier phenotypes, indicating a ROS-caspase pathway in endothelial cell injury. Collectively, our findings show that Stx may impair BBB integrity through ROS accumulation and caspase-dependent apoptosis. This is the first study establishing hCMEC/D3 cells as a model for elucidating Stx-induced BBB disruption, providing mechanistic insights for the therapeutic development against CNS complications in HUS.