Enzymatic Functionalization of Wood as an Antifouling Strategy against the Marine Bacterium Cobetia marina

Weissella cibaria Relieves Gut Inflammation Caused by Escherichia coli through Inflammation Modulation and Gut Microbiota Regulation

The emergence of multi-drug-resistant (MDR) pathogens has considerably challenged the development of new drugs. Probiotics that inhibit MDR pathogens offer advantages over chemical antibiotics and drugs due to their increased safety and fewer side effects. This study reported that Weissella cibaria P-8 isolated from pickles showed excellent antibacterial activity against intestinal pathogens, particularly the antibacterial activity against MDR Escherichia coli B2 was the highest. This study showed that the survival rates of W. cibaria P-8 at pH 2.0 and 0.3% bile salt concentration were 72% and 71.56%, respectively, and it still had antibacterial activity under pepsin, trypsin, protease K, and catalase hydrolysis. Moreover, W. cibaria P-8 inhibits the expression of inflammatory factors interleukin-1β, tumor necrosis factor-α, and interleukin-6, upregulates the interleukin-10 level, and increases total antioxidant capacity and superoxide dismutase enzyme activity in serum. W. cibaria P-8 also efficiently repairs intestinal damage caused by E. coli infection. The gut microbiota analysis demonstrated that W. cibaria P-8 colonizes the intestine and increases the abundance of some beneficial intestinal microorganisms, particularly Prevotella. In conclusion, W. cibaria P-8 alleviated MDR E. coli-induced intestinal inflammation by regulating inflammatory cytokine and enzyme activity and rebalancing the gut microbiota, which could provide the foundation for subsequent clinical analyses and probiotic product development.

Advanced Marine Antifouling Hydrogels Based on 7-Amino-4-methylcoumarin Fluorescence Driven by Rare-Earth Phosphorescence

At present, there are very few reports on the combination of phosphorescence and fluorescence in the field of pollution prevention. A composite antibacterial agent was designed to store energy by using the phosphorescence effect of rare earth oxides, emit light at night, and stimulate 7-amino-4-methylcoumarin to produce fluorescence and prevent algae from adhering. When complexed with PVA, it exhibited excellent characteristics as an all-weather autocatalytic phosphorescence-fluorescence antifouling hydrogel. The rare earth phosphorescent powder was prepared in a high-temperature tube furnace, coated with SiO2 on the surface for waterproofing, and then grafted with 7-amino-4-methylcoumarin to obtain a composite antibacterial agent with a phosphorescence-fluorescence effect. The composite antibacterial agent was added with PVA to obtain a hydrogel, which exhibited bactericidal rates of more than 99.98% against both Gram-positive and Gram-negative bacteria after 48 h. The results of fluorescence staining showed that the coverage rate of dead bacteria reached 41.6% after 24 h. The tensile strength of the antifouling hydrogel is up to 1.49 MPa, which is strong enough for real marine environments. Moreover, the algae coverage area of the composite hydrogel under natural light was only 2.7%, representing a 10-fold reduction compared with the control. The antifouling hydrogel has good antipollution and algae suppression performance, which is due to the fact that the rare earth phosphorescent powder when exposed to sunlight can provide a light source to stimulate 7-amino-4-methylcoumarin fluorescence at night and thereby prevent algae adhesion. After testing in the marine field and the real sea test when wrapped in a fishing net, the excellent antifouling performance was demonstrated. The functional hydrogel has great application potential in the protection of seawater-exposed structures, such as bridges and bay ports.

Urushiol-Based Benzoxazine Containing Sulfobetaine Groups for Sustainable Marine Antifouling Applications

Benzoxazine resins are new thermosetting resins with excellent thermal stability, mechanical properties, and a flexible molecular design, demonstrating promise for applications in marine antifouling coatings. However, designing a multifunctional green benzoxazine resin-derived antifouling coating that combines resistance to biological protein adhesion, a high antibacterial rate, and low algal adhesion is still challenging. In this study, a high-performance coating with a low environmental impact was synthesized using urushiol-based benzoxazine containing tertiary amines as the precursor, and a sulfobetaine moiety into the benzoxazine group was introduced. This sulfobetaine-functionalized urushiol-based polybenzoxazine coating (poly(U-ea/sb)) was capable of clearly killing marine biofouling bacteria adhered to the coating surface and significantly resisting protein attachment. poly(U-ea/sb) exhibited an antibacterial rate of 99.99% against common Gram negative bacteria (e.g., Escherichia coli and Vibrio alginolyticus) and Gram positive bacteria (e.g., Staphylococcus aureus and Bacillus sp.), with >99% its algal inhibition activity, and it effectively prevented microbial adherence. Here, a dual-function crosslinkable zwitterionic polymer, which used an "offensive-defensive" tactic to improve the antifouling characteristics of the coating was presented. This simple, economic, and feasible strategy provides new ideas for the development of green marine antifouling coating materials with excellent performance.

New Challenges in Wood and Wood-Based Materials II

Wood is a natural material that is available in large quantities and is easy to produce, making it the perfect material to consider for the circular economy [...]