No abstract

Here, we elucidated the structural characteristics of a polysaccharide isolated from Gardenia jasminoides Ellis (labeled as GP2a) and its immunomodulatory activity. GP2a is an acidic polysaccharide with a molecular weight of 44.8 kDa, mostly comprising galacturonic acid. Methylation analysis revealed 4-GalpA (74.8%) to be the major sugar residue in GP2a. Nuclear magnetic resonance analysis indicated that its main chain comprised →4)-α-D-GalpA-6-OMe-(1→4)-α-D-GalpA-(1→ and →4)-α-D-GalpA-6-OMe-(1→2)-α-L-Rhap-(1→, with galactan and arabinans linked to the C-4 position of →2)-α-L-Rhap-(1→ residue as branched chains. Furthermore, GP2a showed no obvious toxicity to macrophages (RAW 264.7) while enhancing cell viability in a dose- and time-dependent manner. Compared with untreated cells, nitric oxide production and secretion of cytokines, such as tumor necrosis factor-α, interferon-γ, interleukin (IL)-1β, IL-6, and granulocyte macrophage colony stimulating factor, in GP2a-treated cells significantly increased after 48 h. At 300 µg/mL GP2a concentration, there was no significant difference in the cytokine levels in GP2a- and lipopolysaccharide-treated cells (the positive control). In summary, GP2a is a pectic polysaccharide with homogalacturonan and rhamnogalacturonan-I structural regions in the main chain. Based on its immunomodulatory effects in vitro, GP2a may have potential uses in functional food and medicine.

Mulching significantly increases the crop yield and quality by positively affecting the physical features of the soil. The effect of multiple mulching treatments on soil temperature, yield, and nutrient composition of green asparagus grown in a plastic tunnel was assessed. Two mulch materials: transparent plastic film (PF) and rice husk (RH), were applied and compared with non-mulching treatment (CK). The soil temperatures at the soil surface and 10 cm below it were generally higher in the PF mulch than in the CK during the spring. PF mulch accelerated early spear emergence and growth, which led to harvesting 16 days earlier than in the CK. Under the PF mulch, the early yield of spears increased by 26.6% from January to the end of March, and the annual gross income by 14.8% because of the higher price resulting from the significantly higher marketable spear length and diameter; however, they were reduced in the RH mulch. Most nutrient compositions, such as soluble sugar, ascorbic acid, rutin, flavonoid content, and total antioxidant activity, were significantly increased in the PF mulch treatment. PF mulch might benefit green asparagus production during early spring because of its ability to promote early spear emergence and growth.

The rice stripe virus (RSV) is responsible for devastating effects in East Asian rice-producing areas. The diseasespecific protein (SP) level in rice plants determines the severity of RSV symptoms. Isothermal titration calorimetry (ITC) and bimolecular fluorescence complementation (BiFC) assays confirmed the interaction between an R3H domain-containing host factor, OsR3H3, and RSV SP in vitro and in vivo. This study determined the crystal structure of SP at 1.71 Å. It is a monomer with a clear shallow groove to accommodate host factors. Docking OsR3H3 into the groove generates an SP/OsR3H3 complex, which provides insights into the protein-binding mechanism of SP. Furthermore, SP's protein-binding properties and model-defined recognition residues were assessed using mutagenesis, ITC, and BiFC assays. This study revealed the structure and preliminary protein interaction mechanisms of RSV SP, shedding light on the molecular mechanism underlying the development of RSV infection symptoms.