Calvatia gigantea is a traditional Chinese medicinal fungus known for its diverse pharmacological effects, with polysaccharides being one of its main bioactive components. In this study, a novel homogeneous water-soluble polysaccharide (CGPA1) was successfully isolated and purified from the fruiting body of Calvatia gigantea. The molecular weight of CGPA1 was determined to be 11.69 kDa. Structural characterization was performed using a combination of high-performance gel permeation chromatography (HPGPC), Fourier-transform infrared spectroscopy (FTIR), methylation analysis, and nuclear magnetic resonance (NMR) spectroscopy. The analysis data revealed that CGPA1 is primarily composed of galactose, methyl-galactose, mannose, xylose, and glucose in a molar ratio of 60.01:27.16:10.34:1.83:0.67. The backbone structure predominantly consists of α-1,6-Gal-(1 → and α-1,6 (3-MeO)-Gal-(1→, with side chains of α-Gal and α-Man. Morphological analysis using SEM, XRD, and AFM, combined with Congo red experiments, suggesting that CGPA1 adopts an amorphous granular chain conformation. Both in vitro and in vivo tests confirmed that CGPA1 can promote the migration of MSF cells and accelerate the healing of acute injured wounds. It was found to facilitate skin re-epithelialization, and collagen deposition over the healing process.
Sugars are necessary for plant growth and fruit development. Cucumber (Cucumis sativus L.) transports sugars, mainly raffinose family oligosaccharides (RFOs), in the vascular bundle. As the dominant sugars in cucumber fruit, glucose and fructose are derived from sucrose, which is the product of RFO hydrolysis by α-galactosidase (α-Gal). Here, we characterized the cucumber alkaline α-galactosidase 2 (CsAGA2) gene and found that CsAGA2 has undergone human selection during cucumber domestication. Further experiments showed that the expression of CsAGA2 increases gradually during fruit development, especially in fruit vasculature. In CsAGA2-RNA interference (RNAi) lines, fruit growth was delayed because of lower hexose production in the peduncle and fruit main vascular bundle (MVB). In contrast, CsAGA2-overexpressing (OE) plants displayed bigger fruits. Functional enrichment analysis of transcriptional data indicated that genes related to sugar metabolism, cell wall metabolism, and hormone signaling were significantly downregulated in the peduncle and fruit MVBs of CsAGA2-RNAi plants. Moreover, downregulation of CsAGA2 also caused negative feedback regulation on source leaves, which was shown by reduced photosynthetic efficiency, fewer plasmodesmata at the surface between mesophyll cell and intermediary cell (IC) or between IC and sieve element, and downregulated gene expression and enzyme activities related to phloem loading, as well as decreased sugar production and exportation from leaves and petioles. The opposite trend was observed in CsAGA2-OE lines. Overall, we conclude that CsAGA2 is essential for cucumber fruit set and development through mediation of sugar communication between sink strength and source activity.