Z. morio Hemolymph Relieves E. coli-Induced Mastitis by Inhibiting Inflammatory Response and Repairing the Blood-Milk Barrier

Enhanced virulence of mixed-species Candida biofilms isolated from intragastric balloon patient: insights from larval model

Candida species, particularly Candida albicans and C. tropicalis, are critical members of the human microbiota and are associated with systemic infections, including candidaemia. The pathogenicity is largely attributed to virulence factors such as biofilm formation, which enhances antifungal resistance and immune evasion. Despite extensive research on single-species biofilms, the dynamics of polymicrobial biofilms, especially those involving fungal‒fungal interactions, remain poorly understood. This study investigated the virulence of monomicrobial and polymicrobial biofilms of C. albicans and C. tropicalis formed in vitro, using Zophobas morio larvae as a model. Biofilms were formed from C. albicans and C. tropicalis obtained from the gastric mucosa of a patient with an intragastric balloon (IGB). The biomass and structure of the monomicrobial and mixed-species biofilms were characterized via crystal violet staining and fluorescence microscopy techniques. The virulence of suspended, adhered, and planktonic Z. morio larvae was evaluated via survival assays, monitored over 10 days. C. albicans single biofilms presented greater biomass and structural organization than C. tropicalis, while mixed-species biofilms produced the highest biomass and density. Fluorescence microscopy revealed enhanced interspecies interactions in mixed biofilms, suggesting synergistic effects. Yeasts from single biofilms impacted less on survival rates, particularly under suspended and adhered cell conditions. These findings suggest that mixed-species biofilms exhibit increased virulence due to synergistic interactions between both species. Moreover, they also suggest distinct functional roles within biofilms, where C. tropicalis contributes to cellular proliferation and C. albicans supports matrix production, collectively enhancing biofilm robustness and pathogenic potential. This study underscores the pathogenic significance of fungal‒fungal interactions in biofilms, particularly under mixed-species conditions. The enhanced virulence observed in mixed biofilms highlights the importance of targeting interspecies dynamics in antifungal strategies. The use of alternative models such as Z. morio larvae provides valuable insights into biofilm-mediated infections and potential therapeutic interventions.

Danggui Buxue Decoction Alleviates Inflammation and Oxidative Stress in Mice with Escherichia coli-Induced Mastitis

(1) Background: Bovine mastitis is a lactational disease caused by infection and milk stagnation in the mammary glands. Danggui buxue decoction (DBD), a traditional remedy for blood tonification, anti-inflammation, and antioxidation, has not been used previously to treat mastitis. (2) Methods: In this study, an Escherichia coli mastitis model was established by infecting lactating Kunming mice with clinically isolated bovine mastitis-derived E. coli. Based on this, the effects of DBD on inflammation and oxidative stress in mastitis model mice were evaluated by conducting routine blood tests, H&E staining, qRT-PCR analysis, ELISA, and microcolorimetry. (3) Results: We found that DBD treatment reduced body weight loss, abnormal organ indices, abnormal blood cell counts, pathological damage to breast tissue, and the upregulation of the expression of inflammatory factor in mice caused by E. coli infection. We also found that DBD increased the expression of antioxidants and antioxidant genes and decreased the expression of oxidation products and oxidation-related genes in breast tissue. The therapeutic effect of DBD on inflammation and oxidative stress (OS) in mice occurred through the regulation of the TLR4/NF-κB and Nrf2/HO-1 signaling pathways. (4) Conclusions: DBD imparted its anti-inflammatory and antioxidant effects by inhibiting the TLR4/NF-κB signaling pathway and activating the antioxidant Nrf2/HO-1 signaling pathway.

HCAR2 Modulates the Crosstalk between Mammary Epithelial Cells and Macrophages to Mitigate Staphylococcus aureus Infection in the Mouse Mammary Gland

Staphylococcus aureus (S. aureus) is a major zoonotic pathogen, with mammary gland infections contributing to mastitis, a condition that poses significant health risks to lactating women and adversely affects the dairy industry. Therefore, understanding the immune mechanisms underlying mammary infections caused by S. aureus is essential for developing targeted therapeutic strategies against mastitis. This study identified hydroxycarboxylic acid receptor 2 (HCAR2) as a potential regulator of S. aureus infection in mammary glands. It is demonstrated that HCAR2 deficiency exacerbates the inflammatory response and disrupts the blood-milk barrier in the mammary gland during S. aureus infection, with NLRP3 inflammasome-mediated pyroptosis playing a central role. Activation of HCAR2, on the other hand, suppressed CMPK2 expression, thereby mitigating mitochondrial damage and pyroptosis in mouse mammary epithelial cells (mMECs) induced by S. aureus. Additionally, mitochondrial DNA (mtDNA) released from S. aureus-infected mMECs activates the cGAS/STING signaling pathway in macrophages, impairing their bactericidal activity. In conclusion, this study highlights the critical role of HCAR2 in S. aureus infection of the mammary gland and provides a theoretical basis for identifying potential therapeutic targets for such infections.

Insects as a Prospective Source of Biologically Active Molecules and Pharmaceuticals-Biochemical Properties and Cell Toxicity of Tenebrio molitor and Zophobas morio Cell-Free Larval Hemolymph

Insects are of great interest as novel sources of alternative proteins and biologically active compounds, primarily anticancer agents. Protein-rich insect larval hemolymph is a prospective candidate for pharmaceutical and food industry-related research. In this study, selected biochemical properties and cell toxicity of larval hemolymph from two mealworm species, Tenebrio molitor and Zophobas morio, were analyzed. Total proteins and carbohydrates, antioxidant capacity, and the level of lipid peroxidation were determined. Human cancer (U-87) and normometabolic (MRC-5) cells were treated with different concentrations of larval hemolymph proteins, and the effects on cell viability were assayed 24, 48, and 72 h after treatments. Z. morio hemolymph was shown to be richer in total proteins, showing a higher antioxidant capacity and lipid peroxidation level than T. molitor hemolymph, which was richer in total carbohydrates. Cytotoxicity assays showed that T. molitor and Z. morio hemolymphs differently affect the viability of U-87 and MRC-5 cells in cell type-, dose-, and time-dependent manners. Hemolymph from both species was more cytotoxic to U-87 cells than to MRC-5 cells, which was particularly prominent after 48 h. Additionally, a more potent cytotoxic effect of Z. morio hemolymph was observed on both cell lines, likely due to its higher antioxidant capacity, compared to T. molitor hemolymph.

Zophobas morio larvae as a novel model for the study of Acinetobacter virulence and antimicrobial resistance

The use of mammalian models for in vivo testing of bacterial virulence raises ethical concerns and is expensive and time-consuming. As an alternative, non-mammalian models are sought. Galleria mellonella larvae have been used as a model to study several bacterial pathogens. However, their maintenance is challenging, and commercial supply is low. In this study, we aimed to establish the Zophobas morio larvae as an alternative non-mammalian model for the evaluation of the pathogenicity and antimicrobial susceptibility of Acinetobacter baumannii. We infected Z. morio with Acinetobacter strains and determined the optimal temperature and inoculum. To visualize the bacterial distribution within the larvae, hematoxylin and eosin (H&E) staining was performed. Next, a survival model of infected larvae was established, and virulence was compared between strains. The effect of antimicrobial treatment in relation to antibiotic susceptibility was studied. Our results demonstrate that Z. morio can be used as a model system for in vivo studies of A. baumannii.