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pH-responsive hydrogel antibacterial microspheres were prepared by complex coacervation method and used as drug carriers to load the antibiotic substitute potassium diformate (KDF). The results showed that the three-dimensional network structure of the composite hydrogel was formed among the polysaccharide components, and Zeolite A loaded with KDF was uniformly dispersed in it. The results of drug release behavior and kinetics in vitro showed that the drug release rate was higher and the release mechanism followed the Ritger-Peppas model, which indicated that the antibacterial microspheres had a good pH response. In vitro, the carrier showed broad-spectrum antibacterial activity, good biocompatibility, and degradability. Sodium carboxymethylcellulose and pectin synergistic by hydrogen bonding, potassium dicarboxylate-loaded Zeolite A is filled in a three-dimensional hydrogel network, and chitosan quaternary ammonium salts coat the outer layer. [ABSTRACT FROM AUTHOR]

To improve the application range of waterborne polyurethane (WPU), in this study, nano calcium carbonate/sodium lignosulfonate (CaCO3/SL) composites were prepared using sodium lignosulfonate (SL) wet‐modified calcium carbonate nanoparticles. Then, a series of waterborne polyurethane (WPU) nanocomposites (WPU‐CaCO3/SL) were prepared by solution mixing. Zeta, FT‐IR, XRD, SEM, and TGA were used to characterize the structure and morphology of CaCO3/SL and WPU‐CaCO3/SL. By conducting an analysis on the impact of various dosages of CaCO3/SL composite on the performance of WPU, the findings revealed that the tensile strength of WPU‐CaCO3/SL nanocomposites, when composed with a 3 wt% CaCO3/SL dosage, exhibited a significant increase of 116% from 6.93 to 14.95 mPa. The water contact angle demonstrated a significant increase from 78.3° to 90.1°. Additionally, the maximum decomposition temperature showed a noticeable rise of approximately 7°C. The WPU exhibit enhanced heat resistance, water resistance and mechanical properties, as well as exceptional ultraviolet (UV) absorption capabilities. This study provides a reference for modifying polymers with inorganic fillers and improving the optical properties of polymeric materials. Highlights: Successful modification of nano calcium carbonate using biopolymer SL.Modified CaCO3/SL can be uniformly dispersed in water.Improved thermal stability of WPU composites.WPU composites exhibit excellent mechanical properties and water resistance.Well‐dispersed CaCO3/SL improves ultraviolet radiation resistance of WPU composites. [ABSTRACT FROM AUTHOR]

As a substitute for feed antibiotics, potassium diformate (KDF) can effectively inhibit bacterial overgrowth in the gastrointestinal tract. To avoid the sudden release of KDF in the stomach, this article proposes a new controlled drug delivery system for controlled drug release. In this system, P-type zeolite molecular sieve (Zeolite P) and drug KDF are combined and embedded into the hydrogel microspheres of sodium alginate (ALG) and sodium carboxymethyl cellulose (CMC). In addition, ALG/CMC/Zeolite P composite hydrogel microspheres were prepared with Ca2+ as the crosslinking agent. The structure, composition, morphology, and thermal stability of the hydrogel microspheres were systematically characterized. The effect of the composition ratio of ALG and CMC on the swelling properties of the hydrogel microspheres was also investigated. The results revealed that ALG and CMC form a hydrogen bond and chelate with Ca2+ to form a double crosslinked network structure. Thus, Zeolite P can be effectively encapsulated in the hydrogel microspheres to form a dense three-dimensional network structure. Particularly, Zeolite P helps in improving the thermal stability of microspheres, balance the swelling properties, and control the release of KDF. The drug release results and release kinetics reveal that the ALG/CMC/Zeolite P composite hydrogel has higher drug release in an environment with pH 7.4. The release kinetics follow the Ritger–Peppas model and the first-order kinetic model, which indicates that the composite hydrogel has good specific pH sensitivity. In vitro antibacterial experiments revealed that the composite hydrogel microspheres have broad-spectrum antibacterial activity, and certain inhibitory effects on Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. [ABSTRACT FROM AUTHOR]

The development of microalgae on an industrial scale largely depends on the economic feasibility of mass production. High light induces productive suspensions during cultivation in a tubular photobioreactor. Herein, we report that high light, which inhibited the growth of Chlorella sorokiniana under autotrophic conditions, enhanced the growth of this alga in the presence of acetate., We compared pigments, proteomics and the metabolic flux ratio in C. sorokiniana cultivated under high light ( HL) and under low light ( LL) in the presence of acetate., Our results showed that high light induced the synthesis of xanthophyll and suppressed the synthesis of chlorophylls. Acetate in the medium was exhausted much more rapidly in HL than in LL. The data obtained from LC- MS/ MS indicated that high light enhanced photorespiration, the Calvin cycle and the glyoxylate cycle of mixotrophic C. sorokiniana. The results of metabolic flux ratio analysis showed that the majority of the assimilated carbon derived from supplemented acetate, and photorespiratory glyoxylate could enter the glyoxylate cycle., Based on these data, we conclude that photorespiration provides glyoxylate to speed up the glyoxylate cycle, and releases acetate-derived CO2 for the Calvin cycle. Thus, photorespiration connects the glyoxylate cycle and the Calvin cycle, and participates in the assimilation of supplemented acetate in C. sorokiniana under high light. [ABSTRACT FROM AUTHOR]

The effects of high light (HL) stress on the photosynthetic proteins of green tide-forming macroalga were studied. The naturally grown Ulva prolifera was collected from an intertidal habitat and subjected to 1000 μE m s HL for 12 h. The thylakoid membrane proteins were subsequently extracted and qualitatively analyzed using LC/MS. Quantitative analysis of the thylakoid membrane proteins showed that both PSII reaction center proteins and PSII chlorophyll antenna proteins were decreased. Comparatively, the main PSI reaction center proteins were well preserved. The cytochrome f subunit was significantly decreased, while the other subunits of cytochrome b/ f complex were maintained. These results demonstrated that the HL-induced cytochrome b might play a role in photoacclimation of U. prolifera by involving in cyclic photosynthetic electron transfer (PET) flow around PSII. The LhcSR and PsbS proteins were also identified in U. prolifera, and PsbS was noted to be significantly increased under HL stress. The long-term photoacclimation mechanism of U. prolifera under HL stress might not depend on cyclic PET flow around PSI. [ABSTRACT FROM AUTHOR]