With the rapid advancement of genetic and protein engineering, proteins and peptides have emerged as promising drug molecules for therapeutic applications. Consequently, there has been a growing interest in the field of chemical modification technology to address challenges associated with their clinical use, including rapid clearance from circulation, immunogenicity, physical and chemical instabilities (such as aggregation, adsorption, deamination, clipping, oxidation, etc.), and enzymatic degradation. Polyethylene glycol (PEG) modification offers an effective solution to these issues due to its favorable properties. This review presents recent progress in the development and application of PEGylated therapeutic proteins and peptides (TPPs). For this purpose, firstly, the physical and chemical properties as well as classification of PEG and its derivatives are described. Subsequently, a detailed summary is provided on the main sites of PEGylated TPPs and the factors that influence their PEGylation. Furthermore, notable instances of PEG-modified TPPs (including antimicrobial peptides (AMPs), interferon, asparaginase and antibodies) are highlighted. Finally, we propose the chemical modification of TPPs with PEG, followed by an analysis of the current development status and future prospects of PEGylated TPPs. This work provides a comprehensive literature review in this promising field while facilitating researchers in utilizing PEG polymers to modify TPPs for disease treatment.

A large number of cases of infectious colitis caused by multidrug-resistant (MDR) bacteria, such as Escherichia coli, can result in colon damage and severe inflammation. Vanilla, a widely utilized flavor and fragrance compound, is extensively used in various food. However, the effect of vanilla on MDR E. coli-induced infectious colitis has received less attention. In this study, the antibacterial activity of vanillin against MDR E. coli and other bacteria was determined by the microtiter broth dilution method. The antioxidant and anti-inflammatory capacity of vanillin was assessed in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and MDR E. coli-induced mouse colitis. The results demonstrated that vanillin exhibited potent antibacterial activity against various strains of MDR E. coli, Salmonella, and Staphylococcus aureus, with a minimal inhibitory concentration (MIC) of 1.25–2.5 mg/mL and a minimum bactericidal concentration (MBC) of 5–10 mg/mL; it effectively inhibited cell division in E. coli. Vanillin also displayed remarkable antioxidant activity by suppressing the levels of malondialdehyde (MDA), superoxide dismutase (SOD), and reactive oxygen species (ROS) in LPS-stimulated RAW 264.7 cell; it significantly reduced the production of inflammatory mediators including nitroxide (NO), tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and interleukin 1β (IL-1β), while increasing interleukin 10 (IL-10). In an MDR E. coli-induced mouse colitis model, vanillin effectively inhibited inflammation by suppressing inflammatory cytokines, mitogen-activated protein kinase (MAPK), and nuclear factor κ-B (NF-κB) cell signaling pathway activation; it ameliorated changes in intestinal microflora characterized by decreased Firmicutes richness alongside increased Bacteroides richness, rebalancing the dysbiosis caused by E. coli. These findings highlight the potential pharmacological applicability of vanillin as a promising bioactive molecule for treating infectious colitis.

The global prevalence of aflatoxin B1 (AFB1) and zearalenone (ZEN) contamination in food and feed poses a serious health risk to humans and animals. Recently, enzymatic detoxification has received increasing attention, yet most enzymes are limited to degrading only one type of mycotoxin, and free enzymes often exhibit reduced stability and activity, limiting their practicality in real-world applications. In this study, the laccase CotA gene from ZEN/AFB1-degrading Bacillus subtilis ZJ-2019-1 was cloned and successfully expressed in Escherichia coli BL21, achieving a protein yield of 7.0 mg/g. The recombinant CotA (rCotA) completely degraded AFB1 and ZEN, with optimal activity at 70 °C and pH 7.0. After rCotA treatment, neither AFB1 nor ZEN showed significantly cytotoxicity to mouse macrophage cell lines. Additionally, the AFB1/ZEN degradation efficiency of rCotA was significantly enhanced by five natural redox mediators: acetosyringone, syringaldehyde, vanillin, matrine, and sophoridin. Among them, the acetosyringone-rCotA was the most effective mediator system, which could completely degrade 10 μg of AFB1 and ZEN within 1 h. Furthermore, the chitosan-immobilized rCotA system exhibited higher degradation activity than free rCotA. The immobilized rCotA degraded 27.95% of ZEN and 41.37% of AFB1 in contaminated maize meal within 12 h, and it still maintained more than 40% activity after 12 reuse cycles. These results suggest that media-assisted or immobilized enzyme systems not only boost degradation efficiency but also demonstrate remarkable reusability, offering promising strategies to enhance the degradation efficiency of rCotA for mycotoxin detoxification.

The co-occurrence of aflatoxin B1 (AFB1) and zearalenone (ZEN) in grain-based food and animal feed poses significant health risks to humans and animals due to their potent mutagenic, cytotoxic, and carcinogenic properties. Conventional physical and chemical methods are insufficient for effectively detoxifying multiple mycotoxins present in food and feed. In this study, we evaluated the capability of Bacillus subtilis ZJ-2019-1 (B. subtilis ZJ-2019-1) to simultaneously degrade AFB1 and ZEN while optimizing reaction to enhance degradation efficiency. The localization of active ingredients from B. subtilis ZJ-2019-1 was determined using high-performance liquid chromatography (HPLC). Our findings demonstrated that B. subtilis ZJ-2019-1 eliminated 60.88% of AFB1 and 33.18% of ZEN within 72 h at a concentration of 10 mg/L at 37 °C (pH 7.0) and exerted greater activity under alkaline conditions. The autoclaved and boiled supernatants of B. subtilis ZJ-2019-1 exhibited significant enhancement in the degradation of AFB1 and ZEN, achieving degradation rates of 79.85% and 100%, respectively, at a concentration of 1 mg/L within 48 h at 37 °C. Moreover, the crude enzymes from B. subtilis ZJ-2019-1 showed maximum degradation rates for AFB1 (100%) and ZEN (94.29%) within 72 h at 70 °C. Additionally, divalent cations (such as Co²⁺, Fe²⁺, Mn²⁺, and Ni²⁺) significantly augmented the activity of crude enzymes from B. subtilis ZJ-2019-1 towards mycotoxin degradation. Furthermore, when applied to corn gluten meals, B. subtilis ZJ-2019-1 strain effectively detoxify 66.08% of AFB1 and 22.01% of ZEN, surpassing the efficacy of a commercial detoxification agent on the market (34.17% for AFB1 and 2.28% for ZEN). Collectively, these findings indicated that B. subtilis ZJ-2019-1 is a promising candidate for the simultaneous removal of multiple mycotoxins in food and feed, while addressing health concerns associated with harmful mycotoxins.

Aeromonas veronii is one of the main pathogens causing various diseases in humans and animals. It is currently difficult to eradicate drug-resistant A. veronii due to the biofilm formation by conventional antibiotic treatments. In this study, a marine peptide-N6NH₂ and its analogs were generated by introducing Orn or replacing with D-amino acids, Val and Pro; their enzymic stability and antibacterial/antibiofilm ability against multi-drug resistant (MDR) A. veronii ACCC61732 were detected in vitro and in vivo, respectively. The results showed that DN6NH₂ more rapidly killed A. veronii ACCC61732 and had higher stability in trypsin, simulated gastric/intestinal fluid, proteinase K, and mouse serum than the parent peptide-N6NH₂. DN6NH₂ and other analogs significantly improved the ability of N6NH₂ to penetrate the outer membrane of A. veronii ACCC61732. DN6NH₂, N6PNH₂ and V112N6NH₂ protected mice from catheter-associated biofilm infection with MDR A. veronii ACCC61732, superior to N6NH₂ and CIP. DN6NH₂ had more potent efficacy at a dose of 5 μmol/kg (100% survival) in a mouse peritonitis model than other analogs (50–66.67%) and CIP (83.33%), and it inhibited the bacterial translocation, downregulated pro-inflammatory cytokines, upregulated the anti-inflammatory cytokine, and ameliorated multiple-organ injuries (including the liver, spleen, lung, and kidney). These data suggest that the analogs of N6NH₂ may be a candidate for novel antimicrobial and antibiofilm agents against MDR A. veronii infections.

Probiotics have grown increasingly pivotal for the health of pets, particularly dogs and cats. Emerging research demonstrates that probiotics exert a significant positive impact on gut health, including alleviating intestinal inflammation, regulating gut microbiota balance, and relieving diarrhea symptoms for pets. Regarding nutrient metabolism, probiotics aid in prevention and management of obesity and associated metabolic diseases, primarily by enhancing nutrient digestibility and regulating energy utilization and fat metabolism. Furthermore, probiotics exhibit positive effects, including antiviral activity, immune regulation, and antioxidation. Specific probiotic strains exert their functions via mechanisms such as increasing immunoglobulin levels, suppressing the expression of inflammatory factors, and boosting antioxidant enzyme activity. The underlying mechanisms primarily involve regulating metabolites (e.g., short-chain fatty acids, SCFAs), strengthening the intestinal barrier function, modulating immune responses, and optimizing the gut microbial composition. While existing studies highlight the broad potential of probiotics in preventing and managing various chronic diseases in dogs and cats, their utility in addressing acute illnesses and severe organ damage remains limited. Future research should prioritize investigating species-specific mechanisms of actions and extend to exploring potential applications in the neurological health and behavior of pets.