An antioxidant hydrogel dressing with wound pH indication function prepared based on silanized bacterial nanocellulose crosslinked with beet red pigment extract.

Maintaining wound moisture and monitoring of infection are crucial aspects of chronic wound treatment. The development of a pH-sensitive functional hydrogel dressing is an effective approach to monitor, protect, and facilitate wound healing. In this study, beet red pigment extract (BRPE) served as a native and efficient pH indicator by being grafted into silane-modified bacterial nanocellulose (BNC) to prepare a pH-sensitive wound hydrogel dressing (S-g-BNC/BRPE). FTIR confirmed the successful grafting of BRPE into the BNC matrix. The S-g-BNC/BRPE showed superior mechanical properties (0.25 MPa), swelling rate (1251 % on average), and hydrophilic properties (contact angle 21.83°). The composite exhibited a notable color change as the pH changed between 4.0 and 9.0. It appeared purple-red when the pH ranged from 4.0 to 6.0, and appeared light pink at pH 7.0 and 7.4, and appeared ginger-yellow at pH 8.0 and 9.0. Subsequently, the antioxidant activity and cytotoxicity of the composite was evaluated, its DPPH·, ABTS+, ·OH scavenging rates were 32.33 %, 19.31 %, and 30.06 %, respectively, and the cytotoxicity test clearly demonstrated the safety of the dressing. The antioxidant hydrogel dressing, fabricated with a cost-effective and easy method, not only showed excellent biocompatibility and dressing performance but could also indicated the wound state based on pH changes.

PaLectinL7 enhances salt tolerance of sweet cherry by regulating lignin deposition in connection with PaCAD1.

Lectin receptor-like kinases (LecRLKs), a large family of plant receptor-like kinases, play an important role in plant response to abiotic stresses. However, little information is available about the roles of LecRLKs in the salt stress response of sweet cherry (Prunus avium). Here, an L-type LecRLK gene (PaLectinL7) was characterized from sweet cherry. Subcellular localization analysis revealed that PaLectinL7 is a plasma membrane protein. The expression of PaLectinL7 was up-regulated by salt, drought and exogenously gibberellin treatments. Overexpression of PaLectinL7 in the roots of Gisela 6 enhanced its tolerance to salt stress. Additionally, transcriptome analysis showed that lignin metabolic-related genes were regulated by PaLectinL7 overexpression. Meanwhile, the lignin contents and associated enzymes (CAD and COMT) rose concurrently with PaLectinL7 overexpression under salt stress. We also found that PaCAD1, a key enzyme involved in lignin metabolism, interacted with PaLectinL7 and could be phosphorylated by PaLectinL7 in vitro, suggesting that PaLectinL7 may regulate the enzyme activity of PaCAD1. Therefore, these results indicated that PaLectinL7, as a membrane-bound regulator, promoted lignin deposition by regulating the activities of enzymes related to lignin metabolism, thus enhancing salt tolerance.