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Production of cryopreserved semen in fish generally requires liquid nitrogen (LN), which is not always easily available in remote areas. To reduce reliance on LN, the aim of the present study was to evaluate whether electric freezer could be a feasible LN-free alternative to cryopreserve brown-marbled grouper sperm. After loading, semen straws were put directly into freezers (-30 or -80°C) for freezing and then transferred to LN for storage. Compared with the conventional LN vapour freezing (straws were put horizontally 3 cm above the surface of LN), there was a significant reduction in all tested post-thaw sperm quality parameters in samples frozen at -30°C for 10 min, including kinetic parameters (total motility: 85.0% vs. 48.6%), viability (84.7% versus 51.7%), high mitochondrial membrane potential (86.4% vs. 63.7%), ATP content (106.9 nM/10

The acid- and alkali-soluble polysaccharides (DIPs I and II) were extracted from the fruiting body of Dictyophora indusiata in this work. DIP I comprised of Glc (glucose), Fru (fructose) and Man (mannose), whereas DIP II was of Glc and Fru. Glc was the dominant monosaccharide in both DIPs with relatively molar percentage of >60%, which constructed the backbone of polysaccharide chain. The analysis of the glycosidic linkages indicated that Glc occurred as Glc 1 → 6 in DIP II. The immunological assays showed that both DIPs I and II had a noticeable effect on the hemolysis antibody level in the tested dosage range. However, DIP I could improve the weight of thymus organ and phagocytosis of monocyte. DIP II could restore delayed-type hypersensitivity reaction to dinitrofluorobenzene (DNFB), improving the activity of natural killer cells and the proliferation of splenocytes at high dose.

In this work, quercetin, p -courmaric acid and their derivatives were chosen to evaluate the prooxidant activity in NADPH/peroxidase/H 2 O 2 and DNA cleavage systems. The balance between antioxidant and prooxidant effect was not apparent. The number of hydroxyl groups, hydrophilicity, steric hindrance, concentration and affinity to peroxidase were critical for the prooxidation behaviour of tested compounds. Ortho -methoxy substitution led to a decreased prooxidant activity for p -courmaric acid. The DNA cleavage activity was in a decreasing order, quercetin = rutin > p -courmaric acid > ferulic acid > quercetin 3-O-glucoside. By calculation of Δ E (LUMO−HOMO) and ΔHOF, the reactivity of forming phenoxyl radicals was quercetin > rutin > quercetin 3-O-glucoside, which was in agreement with their DNA cleavage activities. The prooxidant activity order of p -courmaric acid and ferulic acid was in contrast to their reactivities of forming phenoxyl radical. The log P difference should play a critical role in the prooxidation behaviour.

The water-soluble Dictyophora indusiata polysaccharides (DIP) were extracted from the fruiting body of D. indusiata. The structural features of purified DIPs I and II were investigated. The results indicated that DIP I was composed of glucose (Glc) and mannose (Man) with molecular weight of 2100kDa, while DIP II comprised of xylose (Xyl), galactose (Gal), glucose (Glc) and Man with molecular weight of 18.16kDa. The glycosidic linkage of DIP I was composed of →1)-Glc-(6→: →1)-Man-(3,6→ with the ratio of 5.6:1.0, while DIP II was composed of →1)-Glc-(6→: →1)-Man-(3,6→: →1)-Xyl-(5→: →1)-Gal-(3→: →1)-Gal-(6→: with the ratio of 4.9: 15.5: 7.8: 1.0: 5.7. DIP significantly (P0.05) decreased the malondialdehyde (MDA), lipofuscin levels and increased the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities of mice. The strong in vivo antioxidant activity indicated DIP had great potential as functional food.

Banana is a climacteric fruit with desirable palatability and high nutritional value. It ripens rapidly accompanied with metabolite changes during postharvest storage. In this work, morin was applied to treat banana to delay senescence. Nuclear magnetic resonance (NMR) spectroscopy was used to monitor the changes of metabolite composition and levels in banana. The results showed that morin significantly delayed the changes of color and firmness. 1D and 2D NMR spectra reflected that the levels and composition of metabolites were changed with the senescence initiation. The principal component analysis revealed that the first principal components responsible for banana senescence were carbohydrates, amino acids, lipids and phenolics. Morin treatment delayed the transformation of starch to glucose, fructose and sucrose, accelerated the accumulations of alanine and &gamma, Amino-butyrate (GABA), postponed the generations of valine and l-aspartic acid, suppressed the degradation of saponin a. It indicated that morin was effective in delaying banana senescence.

Ziziphus jujuba Mill. var. spinosa (Z. jujuba) seeds have attracted much attention within the field of medicine due to their significant effects against disturbances of the central nervous system. Secondary metabolites composition is key to the influence of the pharmaceutical and commercial qualities of this plant. In this work, the phytochemical profile of Z. jujuba seeds was analysed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and gas chromatography-mass spectrometry (GC-MS). The UPLC-MS/MS information identified the main secondary metabolites in Z. jujuba seeds, including flavonoid C-glycosides, triterpene acids and unsaturated fatty acids. The leading chemical identified by UPLC-MS/MS was betulinic acid, and oleic acid was the leading volatile from the GC-MS results. All the samples tested showed similar phytochemical profiles, but levels of the chemical compounds varied. Principal component analysis revealed the principal secondary metabolites that could define the differences in quality. It was confirmed that the combination of UPLC-MS/MS and GC-MS was an effective technique to demonstrate the pharmaceutical quality of Z. jujuba seeds.