In this work of quercetin’s anti-proliferation action on A. flavus, we revealed that quercetin can effectively hamper the proliferation of A. flavus in dose-effect and time-effect relationships. We tested whether quercetin induced apoptosis in A. flavus via various detection methods, such as phosphatidylserine externalization and Hoechst 33342 staining. The results showed that quercetin had no effect on phosphatidylserine externalization and cell nucleus in A. flavus. Simultaneously, quercetin reduced the levels of reactive oxygen species (ROS). For a better understanding of the molecular mechanism of the A. flavus response to quercetin, the RNA-Seq was used to explore the transcriptomic profiles of A. flavus. According to transcriptome sequencing data, quercetin inhibits the proliferation and aflatoxin biosynthesis by regulating the expression of development-related genes and aflatoxin production-related genes. These results will provide some theoretical basis for quercetin as an anti-mildew agent resource.

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.

Zearalenone (ZEA) has a strong reproductive toxicity. Reducing and eliminating ZEA from food and feed is of great significance. The aim of the present study was to screen bacteria for reduction of ZEA. A pure culture of strain ZJ-2016-1, identified asLysinibacillus sp. by 16S rRNA gene sequence analysis methods, was isolated from chicken large intestine digesta and showed to be effective in eliminating ZEA; 32 μg/ml of ZEA in Luria-Bertani medium was completely removed within 48 h by whole cells of ZJ-2016-1. Heating treatment significantly reduced the removal rate of ZEA from 95.8 to 10.4% in the culture supernatant, suggesting that the microbial reduction of ZEA was likely enzymatic. The optimal conditions for the microbial reduction of ZEA by ZJ-2016-1 included temperature of 37 °C and pH of 7.0. To sum up, these results indicated that theLysinibacillus strain is a promising bacterium resource for reducing ZEA, and its genes and enzymes involved in microbial reduction of ZEA should be further explored.

The purpose of this research was to investigate the toxicity of zearalenone (ZEN) on the growth performance, genital organs, serum hormones, biomarkers, and histopathological changes of female gilts and to evaluate the efficacy of Bacillus subtilis ZJ-2019-1 in alleviating ZEN toxicosis in gilts. Twenty-four female gilts were randomly allocated to four groups with six replicates per group and one gilt per replicate, fed on four feeds prepared previously, which were basic diet (control group, C group), ZEN diet (Z group), Zlb diet (Zlb group) containing B. subtilis ZJ-2019-1 in liquid form, and Zdb diet (Zdb group) containing B. subtilis ZJ-2019-1 in dehydrated form. The results showed that the vulva size and relative weight of reproductive organs had no significant difference in the control group, Zlb group, and Zdb group, but were significantly lower than in the Z group (p < 0.05); the relative weight of the liver was lower in the C group, Zlb group, and Zbd group than in the Z group (0.05 < p < 0.1). The concentration of serum glutamate dehydrogenase (GLDH) was lower, but follicle-stimulating hormone (FSH) was higher in the Z group, Zlb group, and Zdb group than in the Z group (0.05 < p < 0.1). Additionally, serum luteinizing hormone (LH) concentration had no significant difference in the C group, Zlb group, and Zdb group but was significantly lower than in the Z group (p < 0.05); estradiol (E2) was significantly lower in the Zlb group and Zdb group than that in C group, but significantly higher than that in Z group (p < 0.05); PRL was significantly higher in the Zlb group and Zdb group than in the C group, but was significantly lower than in Z group (p < 0.05). ZEN and its reduced metabolites were measured in biological samples after enzymatic hydrolysis of the conjugated forms. The concentration of serum ZEN and its metabolite, α-zeralenol (α-ZOL), had no significant difference in Zlb, Zdb, and control groups but was significantly lower than in the Z group (p < 0.05); urine ZEN and its metabolites, α-ZOL and β-zeralenol (β-ZOL), had no significant difference in Zlb, Zdb, and control groups but was significantly lower than in the Z group (p < 0.05). Cell damages were observed in the liver, uterus, and ovary of gilts in the Z group and alleviated in Zlb and Zdb groups, but the loss of oocytes was irreversible in the ovary. The ZEN-contaminated diet caused serious changes in female hormones and brought harm to the livers and reproductive organs, but B. subtilis ZJ-2019-1 could naturally remove the ZEN significantly, which ameliorated the reproductive impairment in gilts caused by ZEN. The addition of B. subtilis ZJ-2019-1 to ZEN-contaminated feeds could ameliorate the toxic effects effectively, regardless of liquid or dry culture. Therefore, the B. subtilis ZJ-2019-1 strain has great potential industrial applications.