Dynamic covalent nano-networks comprising antibiotics and polyphenols orchestrate bacterial drug resistance reversal and inflammation alleviation.

New antimicrobial strategies are urgently needed to meet the challenges posed by the emergence of drug-resistant bacteria and bacterial biofilms. This work reports the facile synthesis of antimicrobial dynamic covalent nano-networks (aDCNs) composing antibiotics bearing multiple primary amines, polyphenols, and a cross-linker acylphenylboronic acid. Mechanistically, the iminoboronate bond drives the formation of aDCNs, facilitates their stability, and renders them highly responsive to stimuli, such as low pH and high H2O2 levels. Besides, the representative A1B1C1 networks, composed of polymyxin B1(A1), 2-formylphenylboronic acid (B1), and quercetin (C1), inhibit biofilm formation of drug-resistant Escherichia coli, eliminate the mature biofilms, alleviate macrophage inflammation, and minimize the side effects of free polymyxins. Excellent bacterial eradication and inflammation amelioration efficiency of A1B1C1 networks are also observed in a peritoneal infection model. The facile synthesis, excellent antimicrobial performance, and biocompatibility of these aDCNs potentiate them as a much-needed alternative in current antimicrobial pipelines.

GOx-encapsulated iron-phenolic networks power catalytic cascade to eradicate bacterial biofilms.

Bacterial biofilms, especially ones caused by multi-drug resistant strains, are increasingly posing a significant threat to human health. Inspired by nature, we report the fabrication of glucose oxidase-loaded iron-phenolic networks that can power the cascade reaction to generate free radicals to eradicate bacterial biofilms. A soft template, sodium deoxycholate, is employed to guarantee glucose oxidase activity during encapsulation, yielding the porous nanocomplexes after removing the template. The porous nature of nanocomplexes, characterized via transmission electron microscopy, N2 adsorption isotherms, and thermogravimetric analysis, facilitates the diffusion of substrates and products during the cascade reaction and protects glucose oxidase from protease attack. Our optimized nanocomplexes (Fe-GA/GOx) could efficiently kill drug-resistant ESKAPE pathogens, including the clinically isolated strains and eradicate their biofilms. In this regard, Fe-GA/GOx could induce over 90% of the biomass of Klebsiella pneumoniae and Staphylococcus aureus biofilms. In the murine peritonitis infection model induced by Staphylococcus aureus and pneumonia model induced by Klebsiella pneumoniae, our Fe-GA/GOx nanocomplexes could efficiently eradicate the bacteria (over 3-log reduction in colony-forming units) and alleviate the inflammatory response without notable side effects on normal tissues. Therefore, our strategy may provide an efficient alternative treatment to combat bacterial biofilms and address the emergence of drug resistance.

Protein degradation and texture properties of skate (Raja kenojei) muscle during fermentation.

This study aimed at providing new insights into protein degradation and associated textural properties of skate (Raja kenojei) muscles. The pH and ammonia content of skate muscle were found to increase with an increase in fermentation time. During the initial phase of fermentation, the skate muscle hardened prior to demonstrating a spike in its pH and ammonia content. Protein characterization of the skate myofibrils revealed that the high proteins degraded into low molecular peptides, resulting in an increase in the hydrophobic interactions of these myofibrillar protein during fermentation. Consequently, the springiness of the skate muscles significantly (p < 0.05) decreased. Consequently, the textural profile of skate muscle during fermentation has a strong correlation with fermentation time and protein degradation.

Influence of different temperatures on brining kinetics, salt concentration and texture properties of Chinese cabbage (Brassica rapa L. ssp. pekinensis) during brining with ultrasonic treatment.

The effects of ultrasound treatment at different temperatures (4, 10, and 25 ℃) on the brining process of Chinese cabbage were investigated based on their salt diffusion coefficients and texture profiles. Salt weight increased significantly, but water weight decreased in Chinese cabbage treated with ultrasound at increasing temperatures. According to Fick's second equation, the effective diffusion coefficient of Chinese cabbage showed a notable increase as temperature was increased. High temperature caused unfavorable texture properties, and among these, hardness showed the most significant decrease when brining temperature was set at 25 °C. Consequently, results from the texture profile analysis and brining kinetics modeling suggest that optimal brining conditions could be achieved at 10 °C. At this temperature, the diffusion coefficient of Chinese cabbage is higher, the brining time is reduced, and the preferred qualities of kimchi are preserved. PRACTICAL APPLICATION: Ultrasonication is an effective technology that can be utilized in kimchi manufacturing. It presents the advantage of reducing brining time while maintaining the acceptable textural properties of kimchi. This study investigated the impact of different temperatures on the texture properties and brining times of Chinese cabbage during brining and reveal a practical application worthy of further study in food industries and provide valuable information for improving the quality of kimchi.

Physicochemical characteristics and isoflavones content during manufacture of short-time fermented soybean product (cheonggukjang).

Changes in physicochemical properties, isoflavone composition, antioxidant activities, and microbial count of cheonggukjang during the manufacturing process were investigated. During fermentation, isoflavone glucosides are converted to isoflavone aglycones. After fermentation, the increased isoflavone aglycone content was determined. The total phenolic and total flavonoid content, as well as antioxidant activities, significantly increased in cheonggukjang at fermentation process. In proximate composition, fermented soybeans had the highest crude protein content. A gradual increase in the browning index and pH values was observed from the primary processing procedure to fermentation. The total bacterial count increased with each manufacturing step, except for the steamed step. The traditional processing methods for cheonggukjang from raw soybean induced several changes in chemical composition. In addition, the change of isoflavone glucosides to isoflavone aglycones during fermentation could enhance their bioavailability and antioxidant properties.