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Ochratoxin A (OTA) is a significant global contaminant that poses severe challenges to food safety and public health. This study aims to isolate the OTA-degrated probiotics and evaluate genetic and biological characteristic. Here, The degradation rate of a new strain named Bacillus velezensis MM35 isolated from soil was the highest (87.10% within 48 h), and its culture supernatant was the main component of OTA degradation (63.95%) by high performance liquid chromatography. Further investigation revealed that the extracellular enzyme that degrades OTA in the culture supernatant of MM35 may be a small molecule enzyme with certain heat resistance. Genome-wide analysis showed that MM35 contains a cluster of carboxypeptidases encoding OTA-degrading potential, and had good metabolic and catalytic synthesis ability, and strong application potential in the synthesis and degradation of carbohydrates and proteins. A variety of secondary metabolites with antibacterial properties, such as non-ribosomal peptide synthetase and terpenoids, were identified in its metabolites. Consistent with the predicted results, MM35 showed various enzyme production characteristics such as cellulase and xylanase. Furthermore, MM35 could inhibit the growth of a variety of pathogenic bacteria, and showed high co-aggregation ability to Escherichia coli and Salmonella typhimurium. In addition, MM35 has certain tolerance to harsh environments such as strong acid, bile salt, and high temperature. Additionally, the adhesion rate of MM35 was 5.4%, and the invasion rate was 2.1% in IPEC-J2 cells. In summary, the data suggest MM35 isolated strain has high OTA degradation efficiency, antibacterial activity and intestinal colonization, which provided a new way for the treatment of OTA contamination in food and feed industries.

Increases in the virulence and survival of some pathogens in the presence of subinhibitory concentrations of antibiotics have been reported. However, research on the effects of subinhibitory concentrations of antimicrobial substances derived from traditional Chinese medicine on pathogens is still insufficient. Glabridin is a well-known active isoflavone found in licorice roots that possesses a wide range of biological activities. Therefore, in this study, Listeria monocytogenes (L. monocytogenes) exposed to subinhibitory concentrations of glabridin was used as the research object. The minimum inhibitory concentration (MIC) was determined for L. monocytogenes. We investigated the impacts of subinhibitory concentrations of glabridin on the morphology, motility, biofilm formation, adherence, and survival of L. monocytogenes. The results indicated that the MIC of glabridin for L. monocytogenes was 31.25 μg/mL. At 1/8, 1/4, or 1/2 of the MIC, glabridin did not affect the growth, morphology, flagellar production, or biofilm formation of L. monocytogenes. However, subinhibitory concentrations of glabridin inhibited bacterial swimming and swarming motility and decreased the hemolytic activity of L. monocytogenes. Glabridin reduced the hemolytic activity of L. monocytogenes culture supernatants. The results also showed that subinhibitory concentrations of glabridin had no toxic effect on RAW264.7 cells but decreased the intracellular growth of L. monocytogenes in RAW264.7 cells. Furthermore, subinhibitory concentrations of glabridin triggered ROS production but did not induce MET formation in macrophages. In addition, glabridin did not enhance the capacity of L. monocytogenes to trigger METs or the extracellular killing of macrophages by METs. Thus, we conclude that subinhibitory concentrations of glabridin reduce L. monocytogenes motility and hemolytic activity but do not exhibit antimicrobial activity. Glabridin could be an interesting food additive as a bacteriostatic agent with anti-Listeria activity.

Since the 2004 publication of the first study describing extracellular traps (ETs) from human neutrophils, several reports have shown the presence of ETs in a variety of different animals and plants. ETs perform two important functions of immobilizing and killing invading microbes and are considered a novel part of the phagocytosis-independent, innate immune extracellular defense system. However, several pathogens can release nucleases that degrade the DNA backbone of ETs, reducing their effectiveness and resulting in increased pathogenicity. In this review, we examined the relevant literature and summarized the results on bacterial and fungal pathogens and parasites that produce nucleases to evade the ET-mediated host antimicrobial mechanism.

The protection of current influenza vaccines is limited due to the viral antigenic shifts and antigenic drifts. The universal influenza vaccine is a new hotspot in vaccine research that aims to overcome these problems. Polydopamine (PDA), a versatile biomaterial, has the advantages of an excellent biocompatibility, controllable particle size, and distinctive drug loading approach in drug delivery systems. To enhance the immunogenicities and delivery efficiencies of H9N2 avian influenza virus (AIV) epitope peptide vaccines, PDA nanoparticles conjugated with the BPP-V and BP-IV epitope peptides were used to prepare the nano BPP-V and BP-IV epitope peptide vaccines, respectively. The characteristics of the newly developed epitope peptide vaccines were then evaluated, revealing particle sizes ranging from approximately 240 to 290 nm (PDI

Traditional antibiotics have made great contributions to human health and animal husbandry since the discovery of penicillin in 1928, but bacterial resistance and drug residues are growing threats to global public health due to the long-term uncontrolled application of antibiotics. There is a critical need to develop new antimicrobial drugs to replace antibiotics. Antimicrobial peptides (AMPs) are distributed in all kingdoms of life, presenting activity against pathogens as well as anticancer, anti-inflammatory, and immunomodulatory activities; consequently, they have prospects as new potential alternatives to antibiotics. Porcine myeloid antimicrobial peptides (PMAPs), the porcine cathelicidin family of AMPs, have been reported in the literature in recent years. PMAPs have become an important research topic due to their strong antibacterial activity. This review focuses on the universal trends in the biochemical parameters, structural characteristics and biological activities of PMAPs.

Drug-resistant bacteria infections and drug residues have been increasing and causing antibiotic resistance and public health threats worldwide. Antimicrobial peptides (AMPs) are novel antimicrobial drugs with the potential to solve these problems. Here, a peptide based on our previously studied peptide PMAP-36PW was designed via N-terminal myristoylation and referred to as Myr-36PW. The fatty acid modification provided the as-prepared peptide with good stability and higher antimicrobial activity compared with PMAP-36PW in vitro. Moreover, Myr-36PW exhibited effective anti-biofilm activity against Gram-negative bacteria and may kill bacteria by improving the permeability of their membranes. In addition, the designed peptide Myr-36PW could inhibit the bacterial growth of Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa GIM 1.551 to target organs, decrease the inflammatory damage, show an impressive therapeutic effect on mouse pneumonia and peritonitis experiments, and promote abscess reduction and wound healing in infected mice. These results reveal that Myr-36PW is a promising antimicrobial agent against bacterial infections.