Objective To address the limitations of current hair-loss treatments, we employed an in vitro human dermal papilla cell (HDPC) model and a telogen C57BL/6 mouse model to study the effects of Lactiplantibacillus plantarum CCFM1352 fermentation metabolites and bacterial preparations on the hair follicle cycle and decipher the associated molecular mechanisms. Methods HDPCs were treated with different concentrations of CCFM1352 fermentation metabolites or bacterial lysates in vitro, and cell viability as well as the expression of molecules related to Wnt/β-catenin signaling, anagen/catagen regulation, and apoptosis was assessed. Telogen C57BL/6 mice were administrated with the fermentation metabolites or heat-killed bacterial cells by gavage for 21 days, and changes in hair coverage, follicular structure, and associated signaling molecules were analyzed. Results CCFM1352 fermentation metabolites at a volume fraction of 10% increased the viability of HDPCs to 135.30%, up-regulated Wnt10b and FGF-7, down-regulated DKK1 and TGF-β1, and increased Bcl-2 and decreased Bax, inducing a favorable change pattern associated with the anagen phase. Continuous gavage of the fermentation metabolites promoted the transition of hair follicles from telogen to anagen, increased the hair coverage to 61.62%, and enhanced hair follicle density, dermal thickness, and β-catenin accumulation and nuclear translocation. However, the regulatory effects of bacterial lysate and heat-killed bacteria were weaker in both models and showed only limited improvements in some indices. Conclusion CCFM1352 fermentation metabolites could modulate Wnt/β-catenin-related molecules and the expression of key factors such as FGF-7, TGF-β1, Bcl-2, and Bax, which favors the transition of hair follicles from telogen to anagen and suggests an important role in promoting hair growth. This study provides experimental evidence for the application of bioactive metabolites from probiotics in the field of hair health.

Objective To investigate the effects of Chlamydia trachomatis plasmid protein pORF5 on cellular mitophagy and mitochondrial fission and to elucidate whether its mechanism is related to Drp1 activation. Methods HeLa cells stably expressing pORF5 and control cells were constructed by lentiviral transfection. After serum starvation treatment, the expression levels of autophagy-related proteins—microtubule-associated protein 1 light chain 3 (LC3), Beclin-1, and p62—were determined by Western blotting. Co-localization of LC3 and translocase of outer mitochondrial membrane 20 (TOMM20) was assessed by indirect immunofluorescence. Mitochondria were stained with MitoTracker Red CMXRos, and mitochondrial morphology was observed and analyzed through confocal laser scanning microscopy. Dynamin-related protein 1 (Drp1) phosphorylation and its translocation to mitochondria were examined by Western blotting and indirect immunofluorescence. To explore the role of Drp1 in autophagy and mitochondrial fission, we pretreated cells with the Drp1-specific mitochondrial division inhibitor 1 (Mdivi-1). Changes in mitochondrial morphology and Drp1 translocation were evaluated by confocal microscopy and indirect immunofluorescence. Then, Western blotting was employed to determine the expression levels of autophagy-related proteins, and indirect immunofluorescence assay to analyze LC3 fluorescence intensity and its co-localization with TOMM20. Results Compared with the control group, pORF5 significantly upregulated the expression of LC3-Ⅱ and Beclin-1, downregulated the expression of p62, and enhanced the co-localization of LC3 and TOMM20. pORF5 expression led to the fragmentation of the mitochondrial network structure. It promoted Drp1 phosphorylation at Ser616 and enhanced Drp1 translocation to mitochondria. Inhibition of Drp1 with Mdivi-1 attenuated Drp1 phosphorylation and translocation, resulting in elongated mitochondrial morphology. In addition, the Mdivi-1 inhibitor group showed downregulated expression of LC3-Ⅱ and Beclin-1, upregulated the expression of p62, and attenuated co-localization of LC3 and TOMM20. Conclusion The C. trachomatis plasmid protein pORF5 may induce mitophagy and mitochondrial fission by promoting Drp1 phosphorylation and its mitochondrial translocation.

Objective To investigate whether cinnamaldehyde affects the acquisition of exogenous plasmids via conjugative transfer in Vibrio harveyi and to elucidate the potential mechanism. Methods V. harveyi 345 was used as the recipient strain, and an Escherichia coli strain harboring the shuttle plasmid pMMB207 served as the donor. The efficiency of exogenous plasmid acquisition by V. harveyivia conjugative transfer was analyzed before and after cinnamaldehyde treatments at three different stages: Treatment 1 (cinnamaldehyde added during the early logarithmic phase of V. harveyi), Treatment 2 (cinnamaldehyde added during the plate-mating process), and Treatment 3 (cinnamaldehyde added during both stages). Changes in biofilm-forming ability of V. harveyi before and after cinnamaldehyde treatments were assessed. Furthermore, qPCR was used to monitor the changes in the expression of quorum sensing (QS)-related genes under Treatment 1 and Treatment 2. Results Cinnamaldehyde at 0.5, 1, 2, 4, and 8 µg/mL reduced the conjugative transfer efficiency by 59%, 98%, 87%, 85%, and 83% under Treatment 1 and by 51%, 85%, 36%, 93%, and 49% under Treatment 2, respectively. Under Treatment 3, cinnamaldehyde at 1, 2, and 8 µg/mL decreased the conjugative transfer efficiency by 71%, 14%, and 75%, respectively. Cinnamaldehyde treatments did not significantly alter biofilm formation. Under Treatment 1, cinnamaldehyde led to no significant changes in the expression of QS-related genes (P>0.05). Under Treatment 2, after 4 h of conjugation, the treatment with 8 µg/mL cinnamaldehyde downregulated the expression of luxM, luxN, luxS, and luxP by 1.47 to 2.94 folds (P<0.05). Meanwhile, treatments with 0.5-8 µg/mL cinnamaldehyde downregulated luxR expression by 1.16 to 3.19 folds (P<0.05). Conclusion Cinnamaldehyde suppresses conjugative plasmid transfer, most likely by attenuating quorum sensing (QS). This study elucidates the role of cinnamaldehyde as a natural compound in regulating bacterial gene transfer and the potential spread of antibiotic resistance, providing a reference for the development of novel antibacterial adjuvants.

Heyndrickxia coagulans, formerly known as Bacillus coagulans, exhibits pronounced intraspecific heterogeneity and represents an important probiotic candidate for animal feed. Objective To isolate high-quality H. coagulans strains and evaluate their potential for feed applications. Methods H. coagulans strains were isolated from spoiled fruits, soil, and feces through the plate streaking method. The isolates were identified by 16S rRNA gene sequencing. Functional assays were conducted to comprehensively evaluate their feed potential, including acid production, gastrointestinal tolerance, biosurfactant production, antimicrobial activity, protease activity, and utilization of different carbohydrates and feed raw materials. Results A total of 133 strains were isolated, among which 23 strains were identified as H. coagulans. Nine strains with strong acid-producing ability were further selected. Among them, strain N9 isolated from rotten Artocarpus heterophyllus exhibited the highest acid production, decreasing the pH to 3.89±0.05 after 24 h of incubation at 37 °C and achieving a lactic acid yield of (3 370.00±87.36) μg/mL. Following treatment with simulated gastric and intestinal fluids and bile salts, the survival rates of N9 were (73.50±1.54)% and (83.20±1.66)%, respectively. Furthermore, strain N9 showed the strongest biosurfactant production, with an oil displacement diameter of (43.00±0.46) mm. Antimicrobial assays revealed that N9 effectively inhibited three intestinal pathogens: Salmonella enterica subsp. enterica, Escherichia coli, and Staphylococcus aureus. In addition, strain N9 exhibited notable protease activity, with enzymatic characteristics well adapted to the animal intestinal environment. It was capable of utilizing carbohydrates such as xylo-oligosaccharides, as well as feed ingredients including palm kernel meal, cottonseed meal, sunflower meal, soybean meal, and wheat bran for acid production. Conclusion H. coagulans N9, isolated from rotten A. heterophyllus, demonstrates good potential for feed additive, serving as a new candidate strain for the research on probiotic application.

Objective Cyanocobalamin (CN-CbI) requires to be converted into adenosylcobalamin (Ado-CbI) to exert neuroprotective effects, yet its conversion efficiency is impaired under conditions such as chronic sleep deprivation (CSD). This study aimed to obtain a bacterial strain with high efficiency in converting CN-CbI to Ado-CbI that could enhance neuroprotective effects. Methods Lactobacillus paragasseri CCFM1526, a strain capable of converting CN-CbI to Ado-CbI, was isolated via UPLC. A mouse model of CSD was established, and the cognitive functions of mice were evaluated by the novel object recognition and Morris water maze tests. The neuronal structure in the hippocampal dentate gyrus (DG) region was observed via histological staining. Tissue vitamin B₁₂ levels were measured, and the ERK/mTOR signaling pathway along with related neural protein expression was analyzed to assess the neuroprotective mechanism of the fermentation broth. Results Compared with CN-CbI supplementation alone, the fermentation broth of L. paragasseri CCFM1526 significantly improved the cognitive function and alleviated the structural damage in the hippocampal DG region of CSD mice. Intervention with the fermentation broth increased the total vitamin B₁₂ content in the liver, serum, and brain by 10.2%, 16.3%, and 29.0%, respectively (P<0.05). Meanwhile, it activated the ERK/mTOR signaling pathway, leading to increases of 21.5%, 52.4%, 17.3%, and 19.7% in the content of myelin basic protein, postsynaptic density protein 95, brain-derived neurotrophic factor, and nerve growth factor, respectively (P<0.05). Conclusion L. paragasseri CCFM1526 converts CN-CbI into Ado-CbI through fermentation, subsequently activating the ERK/mTOR signaling pathway and upregulating the expression of neurotrophic and myelin repair-related proteins, thereby alleviating CSD-induced nerve injury.

Objective Curcumin exhibits diverse pharmacological activities, yet its clinical and industrial applications are largely limited by its poor water solubility and low oral bioavailability. The present study was designed to evaluate the anti-fatigue efficacy of curcumin fermented by Lactobacillus delbrueckii subsp. bulgaricus CCFM1520 and to preliminarily elucidate the underlying mechanism responsible for its anti-fatigue effects. Methods The bioconversion efficiency of curcumin and its metabolites by CCFM1520 were quantified viain vitro bioconversion assays. A mouse model of fatigue was established by combining forced swimming with chronic restraint stress. Mice were randomized into six groups: blank control, model, curcumin, CCFM1520, CCFM1520-curcumin synbiotic, and CCFM1520-fermented curcumin. The anti-fatigue efficacy of fermented curcumin was comprehensively assessed from behavioral parameters, serum level of oxidative stress markers [superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA)], and cerebral levels of neurotransmitters [dopamine (DA) and norepinephrine (NE)]. Real-time quantitative PCR was performed to examine the mRNA expression profiles of genes associated with the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling pathway in the skeletal muscle and the brain-derived neurotrophic factor/tyrosine kinase receptor B (BDNF/TrkB) signaling pathway in the brain tissue. Results CCFM1520 converted curcumin at an efficiency of 62.39%, efficiently converting it into tetrahydrocurcumin. Compared with unfermented curcumin, the fermented product significantly improved behavioral outcomes, including prolonged exhaustive swimming time, shortened escape latency in the water maze, and increased swimming distance. In addition, the fermented product significantly enhanced the activities of SOD and GSH-Px and reduced the content of MDA in the serum, and simultaneously elevated the levels of DA and NE in the mouse brain. Mechanism studies revealed that fermented curcumin up-regulated the mRNA levels of Nrf2 and HO-1 in the muscle tissue and BDNF and TrkB in the brain tissue. Conclusion L. delbrueckii subsp. bulgaricus CCFM1520efficiently converts curcumin into more bioactive metabolites. These metabolites exert a pronounced anti-fatigue effect by enhancing antioxidant capacity and modulating neurotransmitter balance. This study provides a novel strategy and a theoretical basis for developing high-efficacy anti-fatigue functional foods.

Phytoplankton are key primary producers in marine ecosystems, and their community composition is influenced not only by environmental factors but also by biological factors such as parasitic organisms. However, the relationships between parasitic eukaryotes and phytoplankton in coastal bays remain poorly understood. Objective To investigate the community composition, seasonal succession, and interactions of dominant phytoplankton, including diatoms, dinoflagellates, and their parasitic eukaryotes, Syndiniales, in Sanmen Bay, Zhejiang Province during summer and autumn. Methods Surface water samples were collected from Sanmen Bay in September (summer) and November (autumn) 2019. High-throughput sequencing was performed for the V4 region of the 18S rRNA gene of eukaryotic microbes. Principal coordinate analysis, co-occurrence network analysis, and bipartite network analysis were employed to explore the succession and interactions of diatom, dinoflagellate, and Syndiniales communities. Results Diatom communities exhibited pronounced seasonal variations, with the relative abundance of 36.9% in summer and 5.5% in autumn, being dominated by Cyclotella, Skeletonema, and Thalassiosira. Dinoflagellates showed similar relative abundance in summer (28.0%) and autumn (28.5%), being dominated by Gyrodinium, Heterocapsa, and Gymnodinium. Four Syndiniales groups (group I-IV) were detected in Sanmen Bay, with higher relative abundance in autumn (10.5%) than in summer (7.6%). Among Syndiniales, group I dominated in summer (49.1%), while group Ⅱ dominated in autumn (75.2%). Salinity, nitrate, nitrite, N:P ratio, and Si:N ratio were identified as the main drivers of the dominant phytoplankton and Syndiniales communities. Network analysis indicated that Syndiniales mainly interacted with diatoms and dinoflagellates, with higher interaction frequency in autumn than in summer. Syndiniales were identified as keystone taxa in the interaction network. Conclusion Seasonal succession of diatoms in Sanmen Bay was more pronounced than that of dinoflagellates. Syndiniales groups I and Ⅱ exhibited significant seasonal succession and maintained close interactions with diatoms and dinoflagellates, serving as key taxa in the interaction network. High-throughput sequencing overcame the limitations of microscopy in detecting Syndiniales, providing systematic insights into the community features and potential interactions of dominant phytoplankton and Syndiniales in Sanmen Bay. This study offers important insights into phytoplankton adaptation and interspecies interactions in eutrophic coastal bays.

Objective Planktonic bacteria are essential for marine ecosystem health, yet how mussel aquaculture influences planktonic microbial communities remains unclear. This study aims to clarify the effects of mussel aquaculture on the community structure, diversity, and assembly mechanisms of marine planktonic bacteria. Methods Sixty-eight water samples were collected from a mussel aquaculture area and surrounding areas in Shengsi, Zhejiang, during summer 2024. Integrated analyses of 16S rRNA gene amplicon sequencing data and environmental factors were performed. Results The alpha diversity of particle-attached bacteria (PAB) significantly reduced in the aquaculture area, whereas free-living bacteria (FLB) showed no significant change in alpha diversity but exhibited clear shifts in beta diversity and phylogenetic structure. Random forest analysis identified Pseudomonadales and Bdellovibrionaceae as indicator taxa within the aquaculture area, and their changes might be associated with organic matter inputs and altered nutrient conditions. Functional prediction indicated enhanced nitrogen cycling (especially nitrification and aerobic ammonia oxidation) and a shift toward reductive acetogenesis in carbon cycling, alongside suppressed methanogenesis in the aquaculture area. Microbial community assembly was governed mainly by deterministic processes (e.g., heterogeneous selection) in the aquaculture area but by stochastic processes in surrounding waters. Conclusion This study demonstrates that mussel aquaculture can reconfigure the structures, functions, and assembly mechanisms of planktonic bacterial communities, providing insights for ecological impact assessment of mariculture.

Excessive nitrogen input caused by eutrophication in nearshore waters is a major environmental stressor driving the global degradation of seagrass beds. Objective To screen and identify efficient aerobic denitrifying bacteria from seagrass bed ecosystems and elucidate their nitrogen removal performance and mechanisms, thus providing microbial resources for alleviating nitrogen loading and restoring eutrophic seagrass beds. Methods Aerobic denitrifying bacteria were isolated and screened from seagrass rhizosphere sediments in Zhifu Bay, Yantai by enrichment-domestication culture and bromothymol blue assay. The taxonomic status of the strains was determined by 16S rRNA gene sequencing. On the basis of nitrogen removal performance, an efficient aerobic denitrifying strain was selected. Single-factor and orthogonal experiments were conducted to optimize its denitrification conditions, and nitrogen balance experiments and whole-genome sequencing were employed to elucidate its nitrogen removal pathways and key functional genes. Results A total of 34 denitrifying strains were isolated from seagrass rhizosphere sediments in Zhifu Bay, Yantai. The dominant genera were Pseudomonas and Acinetobacter. A strain designated as Pseudomonas sp. S22 with high denitrification performance was selected. The denitrification conditions of this strain were optimized as follows: sodium succinate as the carbon source, C/N=15, pH 9.0, salinity (S)=30‰, and T=28 ℃. Under these conditions, the strain achieved a removal rate of 99.99% for 140 mg/L nitrate nitrogen within 36 h, demonstrating excellent nitrogen removal efficiency. Nitrogen balance analysis revealed that approximately 59.64% of the initial nitrate nitrogen was converted to gaseous nitrogen, confirming that denitrification was the dominant nitrogen removal pathway. Genomic sequencing revealed that strain S22 carried key functional genes for aerobic denitrification, including napA and nirS, providing a genetic basis for its denitrification phenotype at the molecular level. Conclusion This study systematically isolated and identified aerobic denitrifying bacteria from seagrass beds in northern China. Strain S22 exhibits outstanding nitrogen removal performance and environmental adaptability. Nitrogen balance and genomic analyses confirm that denitrification is its primary nitrogen removal pathway and the strain carries key functional genes for aerobic denitrification. Strain S22 can serve as a potential microbial resource for reducing nitrogen loading in seagrass beds. This study provides both a valuable strain and a theoretical basis for the future development of microbe-seagrass synergistic remediation technologies.

Objective To elucidate the tolerance mechanisms of Penicillium oxalicum Z2 to flavonoids present in licorice residues and to analyze its transcriptional responses under gradient stress concentrations, thereby providing a theoretical basis for breeding resistant strains and improving fermentation efficiency. Methods P. oxalicum Z2 was treated with different concentrations of licorice flavonoids (0, 0.25, 0.50, 1.00, and 2.00 mg/mL). Physiological indicators were systematically measured. Transcriptome sequencing was conducted to identify differentially expressed genes and enriched KEGG/GO pathways, revealing the molecular adaptation mechanisms of P. oxalicum Z2 under flavonoid stress. Results As the flavonoid concentration increased, P. oxalicum Z2 maintained high biomass and cellulase activity. Under the highest flavonoid concentration (2.00 mg/mL), its biomass reached 4.840 g/L, and the activities of endoglucanase, β-glucosidase, filter paper enzyme, and xylanase reached 74.78, 3.24, 6.99, and 562.5 U/mL, respectively, which were more than ten folds of those in the conventional P. oxalicum strain. Transcriptome analysis showed that the number of differentially expressed genes increased in a concentration-dependent manner, from 818 in the Low group to 3 945 in the Super group. Under low stress (≤1.00 mg/mL), the strain reprogrammed carbohydrate metabolism and ABC transporter pathways to adjust carbon utilization and sustain essential cellular activities. Under high stress (2.00 mg/mL), it further activated the ribosome and oxidative phosphorylation pathways, with 65 genes upregulated in the ribosome pathway. Conclusion This study identified key genes (e.g., EF-Tu, SecY,and FtsY) and core pathways (e.g., oxidative phosphorylation and ABC transporter), demonstrating that P. oxalicum Z2 employed tiered responses to licorice flavonoid stress. Specifically, the strain remodels sugar metabolism and transmembrane transport under low flavonoid stress to maintain survival and activates ribosome and energy metabolism compensation mechanisms under high flavonoid stress.