The excessive use of synthetic preservatives poses significant threats to food safety and human health. This study systematically investigated the genetic characteristics of the Limosilactobacillus fermentum (L. fermentum) z-6 strain, the antibacterial properties of the bacteriocin-like substance (FC) it produces, and its mechanism of action. The results demonstrated that this bacteriocin-like substance exhibited remarkable antimicrobial activity and exceptional stability, maintaining high activity across a broad pH range (4.0–8.0) and withstanding heat treatment at 100 °C and UV irradiation, indicating robust environmental adaptability. Its proteinaceous nature was confirmed by its detection below 1 kDa on Tricine-SDS-PAGE and its inactivation by trypsin and pepsin. The FC showed broad-spectrum inhibition against foodborne pathogens, including Salmonella enterica serovar Typhimurium, E. coli, A. baumannii, S. aureus, P. mirabilis and L. monocytogenes. Mechanistic investigation demonstrated that the FC exerts antibacterial effects primarily through membrane disruption, as evidenced by a live-dead staining assay confirming significantly enhanced permeability in Salmonella enterica serovar Typhimurium, and scanning electron microscopy revealing distinct pore formation on bacterial surfaces. It is speculated that the FC produced by z-6, due to its excellent properties and outstanding antibacterial performance, could potentially serve as a natural biopreservative.

Aeromonas hydrophila is a typical pathogen that causes fish diseases and can easily infect different fish species. This study investigated the antibacterial activity, physicochemical properties and antibacterial mechanism of the BLIS UI-11 produced by Lactobacillus plantarum HYH-11, isolated from traditional kimchi in Hebei, China. It was found that BLIS UI-11 showed excellent inhibitory effect on the growth of A. hydrophila, and it also had a good antibacterial effect on various pathogens such as Vagococcus fluvialis, Listeria monocytogenes, Aeromonas dhakensis, Aeromonas salmonicida, Salmonella Typhimurium, Escherichia coli and Staphylococcus aureus. By measuring growth kinetics, it was found that the maximum antibacterial activity was reached after 30 h of culture, and both the optical density value at 600 nm (OD₆₀₀₎ and pH basically entered the stable phase after 20 h. Whole-genome analysis and gene cluster prediction identified a RiPP-like biosynthetic gene cluster, which comprises genes encoding precursor peptides, modification enzymes, and transport/immunity components. The molecular weight of the antimicrobial active substance was detected by dialysis and Tricine-SDS-PAGE, and it was shown to be an ultra-small molecular substance (<1 kDa). BLIS UI-11 was sensitive to protease K, but its antibacterial activity remained stable after treatment with acidic environment (pH 3.0–6.0), high-temperature treatment (121 °C for 30 min), and ultraviolet irradiation (4 h). After the sub-live cell assay (PI/SYTO9) and scanning electron microscopy (SEM), BLIS UI-11 inhibited the growth of bacteria by destroying the cell membrane of A. hydrophila to deform, collapse, and form holes that lead to accounting leakage. The hemolysis assay indicated that BLIS UI-11 exhibited incomplete hemolysis, suggesting its safety for application. The results showed that BLIS UI-11 produced by strain HYH-11 has great potential as an antimicrobial agent against A. hydrophila infection.

Uncoupling protein 1 (UCP1) is a mitochondrial inner-membrane carrier classically recognized as the molecular effector of non-shivering thermogenesis in brown adipose tissue. By dissipating the proton-motive force generated by oxidative phosphorylation, UCP1 converts stored chemical energy into heat and enables adaptive thermogenesis during cold exposure. The rediscovery of metabolically active brown adipose tissue (BAT) and inducible beige adipocytes in adult humans has renewed interest in UCP1-positive thermogenic adipose tissue as a regulator of systemic metabolism and a potential target for therapeutic modulation in obesity and cardiometabolic disease. Beyond thermogenesis, accumulating evidence indicates that UCP1-positive brown/beige adipocytes and thermogenic adipose tissue are involved in lipid and glucose metabolism, mitochondrial redox homeostasis, inflammatory remodeling, organ protection, and tumor-associated metabolic adaptation, mainly through adipocyte-autonomous mechanisms and adipose–organ communication. However, UCP1 biology is complex: BAT activity measured by imaging does not directly quantify UCP1 proton conductance, non-adipose UCP1 expression is often low and technically challenging to validate, local cell-autonomous UCP1 function in non-adipose tissues remains controversial, and UCP1-independent thermogenic pathways may compensate in selected contexts. In this review, we summarize the molecular and structural basis of UCP1 function, its regulation at transcriptional and post-transcriptional levels, and its biological roles in cellular and systemic homeostasis, with explicit distinction between direct adipocyte-autonomous UCP1 functions, indirect systemic effects mediated by thermogenic adipose tissue, and preliminary or incompletely validated evidence of local UCP1 activity in non-adipose cells. We further discuss the association of UCP1-positive thermogenic adipose tissue with obesity, type 2 diabetes mellitus (T2DM), cardiovascular disease, kidney injury, liver disease, neurological disorders, and cancer. Finally, we evaluate UCP1-related thermogenic adipose tissue activity as a biomarker and therapeutic target, highlighting current limitations, safety concerns, and future directions for precision metabolic medicine.

Objective: P. mirabilis is a Gram-negative rod-shaped bacterium. In this study, the SH-8 strain of P. mirabilis was isolated from swine-derived samples, and its antibiotic resistance genes (ARGs) and transmission mechanisms were systematically characterized. Methods: The minimum inhibitory concentrations (MICs) of strain SH-8 were determined by the broth microdilution method, with genomic features analyzed through whole-genome sequencing (WGS). Results: P. mirabilis SH-8 exhibited resistance to multiple antimicrobial agents. Its genome consists of a single chromosome (3,993,987 bp; GC content 38.8%) and one plasmid. WGS identified 21 distinct ARGs in this strain, along with a class 2/1 hybrid integron. Furthermore, a heatmap analysis of resistance genes from 29 P. mirabilis isolates of diverse origins revealed a striking similarity between the resistance gene profile of SH-8 and those of other strains. Conclusions: The MDR exhibited by P. mirabilis SH-8 is primarily attributed to integron-mediated resistance gene clusters within its genome, which may pose challenges for treating opportunistic infections caused by this bacterium.

Research has demonstrated that the presence of synthetic preservatives tends to disrupt the balance of the gut microbiota, thereby posing a significant threat to food safety and human health. The present study investigates the antibacterial activity of a novel bacteriocin-like produced by Latilactobacillus sakei (L. sakei) against Escherichia coli (E. coli), as well as its mechanism of action. This study aims to validate the significant antibacterial effect of bacteriocin-like YY-1 produced by L. sakei W-1 through dialysis combined with Tricine-SDS-PAGE analysis, and to determine its molecular weight. The results of the study indicate that the molecular weight of the bacteriocin-like is less than 2.7 kDa. Moreover, this bacteriocin-like YY-1 exhibits broad-spectrum antimicrobial properties, demonstrating antibacterial activity against E. coli, S. Typhimurium, A. baumannii, P. mirabilis, S. aureus, L. monocytogenes. Furthermore, bacteriocin-like YY-1 exhibits optimal antibacterial activity at a pH of 4.0, with its activity gradually diminishing as pH increases. It is completely inactivated by trypsin treatment, while papain and proteinase K treatments significantly reduce its antibacterial activity. Additionally, this bacteriocin-like YY-1 has been demonstrated to inhibit the growth of E. coli and disrupt its normal development. The Viable/Necrotic Cell Stain and SEM observations confirmed that the bacteriocin-like compound induces cell death by forming distinct pores through the disruption of the cell membrane’s structural integrity. In summary, YY-1—a bacteriocin-like substance characterised by its low molecular weight (<2.7 kDa), broad-spectrum activity, and pore-forming mechanism—is a highly promising natural alternative to synthetic preservatives, capable of mitigating the damage caused by chemical additives to the gut microbiota.

Escherichia coli is a common porcine diarrheal pathogen transmitted via the fecal–oral route through contaminated environments and feed. This study evaluated the antimicrobial potential of a bacteriocin-like substance produced by Loigolactobacillus coryniformis WYQ-2 isolated from pickled vegetables. Its physicochemical stability, molecular mass, and antimicrobial spectrum were characterized, and the mode of action against Escherichia coli was investigated through intracellular ATP quantification, live/dead staining, and scanning electron microscopy (SEM). The substance exhibited broad-spectrum antibacterial activity, with the strongest inhibition against Escherichia coli (the diameter of the inhibition zone reached 41.35 mm). It remained stable under prolonged UV irradiation (0–2.5 h), under heating at 100 °C, and within the pH range of 3.0–9.0. Molecular mass determination revealed a low-molecular-weight peptide (<2.7 kDa). Protease susceptibility tests showed activity was reduced by trypsin and papain, slightly sensitive to proteinase K, yet relatively stable toward other tested proteases. Mechanistically, ATP levels declined markedly within 0.5–2 h of treatment, while live/dead staining and SEM confirmed membrane disruption, deformation, and surface indentations in treated Escherichia coli cells. These findings demonstrate that the WYQ-2-derived bacteriocin-like substance possesses favorable physicochemical traits and exerts antibacterial action primarily by compromising membrane integrity, highlighting its promise as a natural alternative for controlling porcine diarrheal diseases.