Kiwifruit bacterial canker caused by Pseudomonas syringae pv. actinidiae (Psa), has led to substantial economic losses worldwide and represents a major challenge to kiwifruit cultivation. Due to the inadequate effectiveness and environmental safety of current treatments, there is a pressing demand for novel antimicrobial compounds, such as antimicrobial peptides (AMPs). In this study, two AMPs, P255 and P256, previously designed by our group, were used to determine their efficacy against Psa in kiwifruit. P256 with a minimum inhibitory concentration of 18.75 µg/mL demonstrated stronger antimicrobial activity against Psa than did P255. P256 and P255 showed synergistic effect when combined with EDTA. In addition, they effectively inhibited the biofilm formation, and regulated the expression of genes related to Psa biofilm formation. Both peptides bound with the lipopolysaccharide of Psa, targeted the membrane and increased the permeability of Psa cell membrane, resulting in calcium leakage. P256 and P255 disrupted the cellular morphology and intracellular structure of Psa cells. They also bound to the genomic DNA of Psa and induced the accumulation of intracellular reactive oxygen species. In experiments on infected leaf discs, P256 and P255 displayed superior control of Psa compared to commercial agricultural streptomycin. Collectively, P256 and P255 efficiently controlled Psa in kiwifruit and could be further developed as a new eco-friendly bactericidal agents.
Food allergy is an adverse health condition with global distribution and prevalence, with no cure. The main approach for prevention is strict avoidance of the allergen in the food. New alternatives to prevent or reduce symptoms are necessary to improve quality of life, such as probiotics. This study aimed to evaluate the ability of Lacticaseibacillus (Lact.) rhamnosus CRL75 to prevent allergic enteritis development when administered in drinking water or in fermented milk in an ovalbumin (OVA)-induced intestinal allergy mouse model. Preventive and simultaneous administration of CRL75 in drinking water and in fermented milk significantly reduced OVA-specific immunoglobulin (Ig) E but increased OVA-specific IgG, IgG1, and IgG2a. In addition, CRL75 induced release of interferon gamma (IFN-γ) and interleukin (IL) 10, decreasing IL-4 and IL-6 in serum, and reduced eosinophil recruitment to the intestine. Splenocytes from CRL75-treated mice showed significantly reduced secretion of IL-4 and IL-6 and increased IFN-γ, IL-10, and tumor necrosis factor alpha (TNF-α). Preventive administration of CRL75 in drinking water and fermented milk reduced Th2 immune response in OVA-induced intestinal allergy, leading to a Th1 response. Lact. rhamnosus CRL75 represents a viable, useful, and affordable alternative for the design of novel functional foods aimed at contributing to the prevention of allergic enteritis. Moreover, it is the first report to compare and demonstrate that in both fermented milk or drinking water, Lact. rhamnosus CRL75 prevents and reduces allergic reactions, shifting the Th1/Th2 balance towards the Th1 response.
Hyperlipidemia, caused by dysregulated lipid metabolism, is closely associated with cardiovascular risk. This study developed a lipid-lowering beverage by fermenting lotus leaf (Nelumbo nucifera) extract with functional lactic acid bacteria (LAB). Three strains, Lactobacillus paracasei GY-L077, Lactiplantibacillus plantarum GY-L085, and Lacticaseibacillus rhamnosus RB-01, were selected from traditional fermented foods for their antibacterial activity, gamma-aminobutyric acid production, lipase production, and acid and bile salt tolerance. A composite starter was constructed and the fermentation process was optimized by response surface methodology, yielding a beverage with 4.17 × 107 CFU/mL viable cells and favorable sensory quality. In high-fat diet (HFD)-fed mice, the fermented beverage significantly suppressed body weight gain and fat accumulation, improved serum lipid profiles by reducing triglycerides, total cholesterol, and low-density lipoprotein cholesterol while increasing high-density lipoprotein cholesterol, and alleviated hepatic steatosis. 16 S rDNA sequencing showed that these effects are associated with changes in gut microbiota composition, including increased microbial diversity, a reduced Firmicutes/Bacteroidetes ratio, and increased Akkermansia abundance. These findings support LAB-fermented lotus leaf beverage as a functional food candidate for lipid improvement and provide a strategy for the high-value utilization of lotus leaves.
Histones are classical DNA-binding proteins, rich in cationic amino acids, and recently also reported as effective antimicrobial agents against a range of Gram-negative and Gram-positive pathogens. While histones with antimicrobial functions have been identified in various marine organisms, little is known regarding the identification and characterisation of innate antimicrobial proteins and peptides, including histones, from macroalgae species. This study aimed to develop an isolation and purification protocol for histones by combining in-silico analyses with wet-laboratory techniques to identify and isolate core histones from the red macroalga Chondrus crispus. The antimicrobial properties of the purified core histone were examined against a variety of pathogenic bacteria using both minimum inhibitory concentration (MIC) and disk diffusion assays. The purification of the core histone fraction was assessed using SDS-PAGE analysis. The findings indicated that the core histone extracted from C. crispus displayed antimicrobial properties against a range of Gram-positive and Gram-negative bacteria, including Escherichia coli, Staphylococcus aureus, and the marine pathogens Vibrio anguillarum and Yersinia ruckeri. Furthermore, the purified core histone was digested by trypsin into peptides. The resulting peptides exhibited enhanced bacterial inhibition against both E. coli and S. aureus. These results indicate, for the first time, that C. crispus histone proteins and peptides possess antimicrobial activity. In addition to its antimicrobial properties, the purified core histone showed minimal cytotoxic effects when tested in mammalian cells. As a result, the core histone obtained from C. crispus shows potential as a novel antimicrobial candidate, supporting further evaluation across additional mammalian cell types.
Inflammatory bowel disease (IBD) encompasses a group of chronic inflammatory disorders of the intestine, which have been associated with a rising global incidence. Autophagy plays a crucial anti-inflammatory role in the context of intestinal inflammation. This study was designed to investigate the protective effects of Lactobacillus plantarum-derived extracellular vesicles (LpEVs) against dextran sodium sulfate (DSS)-induced colitis in mice and to elucidate the underlying mechanisms associated with autophagy. In this study, mouse intestinal epithelial cells (MODE-K) were pre-incubated with LpEVs and subsequently stimulated with lipopolysaccharide (LPS) to establish an inflammatory model. Our findings indicate that LpEVs can inhibit LPS-induced inflammation. Additionally, we explored the potential effects of LpEVs in alleviating DSS-induced colitis. C57BL/6 mice received LpEVs at a dose of 1 µg/g body weight by oral gavage before the induction of colitis with DSS. The results demonstrated that LpEVs significantly alleviated the severity of DSS-induced colitis. Furthermore, LpEVs exert anti-inflammatory activities, which are accompanied by alterations in autophagy-related markers and reduced NLRP3 expression, contributing to the alleviation of intestinal inflammation. These findings support the potential application of LpEVs for colitis intervention, thereby laying a scientific foundation for Lactobacillus-derived therapeutic strategies against colitis.
