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Alginate oligosaccharides (AOs), derived from alginate degradation, exhibit diverse biological activities and hold significant promise in various fields. The enzymatic preparation of AOs relies on alginate lyases, which offers distinct advantages. In contrast to the conventional use of sodium alginate derived from brown algae as the substrate for the enzymatic preparation of AOs, AO preparation directly from brown algae is more appealing due to its time and energy efficiency. Thus, the identification of potent alginate lyases and cost-effective brown algae substrates is crucial for optimizing AO production. Herein, we identified and characterized an alginate lyase, AlyP18, capable of efficiently decomposing algae, from a marine bacterium Pseudoalteromonas agarivorans A3 based on secretome analysis. AlyP18 is a mesothermal, endo-type and bifunctional alginate lyase with high enzymatic activity. Two brown algae substrates, Laminaria japonica roots and Macrocystis pyrifera, were used for the AO preparation by AlyP18. Upon optimization of AlyP18 hydrolysis parameters, the substrate degradation efficiency and AO production reached 53% and ~32% for L. japonica roots, respectively, and 77% and ~46.5% for M. pyrifera. The generated AOs primarily consisted of dimers to pentamers, with trimers and tetramers being dominant. This study provides an efficient alginate lyase and alternative brown algal feedstock for the bioconversion of high-value AOs from brown algae. [ABSTRACT FROM AUTHOR]

Background: Acanthopanax senticosus (Rupr. et Maxim.) is commonly used in Traditional Chinese Medicine. Syringin is a major ingredient of phenolic glycoside in Acanthopanax senticosus. Objective: This study was performed to investigate whether Syringin could protect high glucose-induced bone marrow mesenchymal stem cells (BMSCs) injury, cell senescence, and osteoporosis by inhibiting JAK2/STAT3 signaling. Methods: BMSCs isolated from both the tibia and femur of mice were induced for osteogenesis. The cell senescence was induced using the high glucose medium. The cells were treated with 10 and 100 ^mol/l Syringin. Immunohistochemistry staining was performed to determine the p-galactosidase (SA-p-gal) levels in differentially treated BMSCs. MTT assay and flow cytometry analysis were also performed to assess cell viability and cell cycle. The level of ROS in cells with different treatment was measured by using flow cytometry with DCF-DA staining. Calcium deposition and mineralized matrices were detected with alizarin red and ALP staining, respectively. Osteogenesis related genes OCN, ALP, Runx2, and BMP-2 were detected by RT-PCR. Levels of senescence-related proteins including p53 and p21, as well as JAK2, p-JAK2, STAT3, and p-STAT3 were detected by Western blot analysis. Results: Syringin treatment reversed the phenotypes of senescence caused by high glucose in BMSCs, including the arrest of G0/G1 cell cycle, enhanced SA-p-gal activity, and impaired cell growth. Syringin also decreased the elevated ROS production and the levels of p53, p21, and JAK2/STAT3 signaling activation. In addition, Syringin also enhanced the osteogenic potential determined by ARS and ALP staining, as well as increasing OCN, ALP, Runx2, and BMP-2 expressions. Conclusion: Syringin protects high glucose-induced BMSC injury, cell senescence, and osteoporosis by inhibiting JAK2/STAT3 signaling. [ABSTRACT FROM AUTHOR]

SUMMARY: In the field, necrosis area induced by pathogens is usually surrounded by a red circle in apple fruits. However, the underlying molecular mechanism of this phenomenon remains unclear. In this study, we demonstrated that accumulated salicylic acid (SA) induced by fungal infection promoted anthocyanin biosynthesis through MdNPR1‐MdTGA2.2 module in apple (Malus domestica). Inoculating apple fruits with Valsa mali or Botryosphaeria dothidea induced a red circle surrounding the necrosis area, which mimicked the phenotype observed in the field. The red circle accumulated a high level of anthocyanins, which was positively correlated with SA accumulation stimulated by fungal invasion. Further analysis showed that SA promoted anthocyanin biosynthesis in a dose‐dependent manner in both apple calli and fruits. We next demonstrated that MdNPR1, a master regulator of SA signaling, positively regulated anthocyanin biosynthesis in both apple and Arabidopsis. Moreover, MdNPR1 functioned as a co‐activator to interact with and enhance the transactivation activity of MdTGA2.2, which could directly bind to the promoters of anthocyanin biosynthetic and regulatory genes to promote their transcription. Suppressing expression of either MdNPR1 or MdTGA2.2 inhibited coloration of apple fruits, while overexpressing either of them significantly promoted fruit coloration. Finally, we revealed that silencing either MdNPR1 or MdTGA2.2 in apple fruits repressed SA‐induced fruit coloration. Therefore, our data determined that fungal‐induced SA promoted anthocyanin biosynthesis through MdNPR1‐MdTGA2.2 module, resulting in a red circle surrounding the necrosis area in apple fruits. Significance Statement: Pathogen‐stimulated salicylic acid promotes anthocyanin biosynthesis through MdNPR1‐MdTGA2.2 module, which facilitates formation of a red circle surrounding the necrosis region induced by pathogens. This work not only dissects a possible pathway that uncovers the molecular mechanism of pathogen‐induced anthocyanin accumulation but also complements and extends the biotic factors that modulate anthocyanin synthesis in plants. [ABSTRACT FROM AUTHOR]

Transition metal/nitrogen-doped carbon catalysts (M–N–C) show superior catalytic activity in electrocatalytic CO2 reduction due to their high atomic efficiency. In this work, a series of electrocatalysts with cobalt phthalocyanine (CoPc) highly dispersed on M–N–C were prepared. Compared to the pure M–N–C materials, all CoPc/M–N–C catalysts showed a significantly enhanced activity for CO2 reduction and suppressed hydrogen evolution reaction. Among these catalysts, CoPc/Fe–N–C exhibits an outstanding activity and selectivity for CO2 reduction with 99% faradaic efficiency for CO at a potential of −0.48 V vs. RHE. Obviously, such a composite strategy is considered as one of the effective methods to improve the selectivity of CO2 to CO. [ABSTRACT FROM AUTHOR]