Calcium maintained higher quality and enhanced resistance against chilling stress by regulating enzymes in reactive oxygen and biofilm metabolism of Chinese winter jujube fruit.

The postharvest senescence of Chinese winter jujube fruit can be effectively delayed by refrigerated storage. However, chilling injury often occurs in jujube fruit during cold storage. In this study, Chinese winter jujubes were sprayed with CaCl2 (4%) 3 times at intervals of 2 hr on the day of refrigeration. The results presented that maximum difference of 2.7 N firmness, 3.42% TAC, and 0.8 OD280 /g polyphenol content were detected in calcium-treated fruit during cold storage, but the levels of O2- , MDA, hydrogen peroxide, browning rate, electrolyte leakage, and weight loss rate were significantly inhibited (p < .05). The maximum difference of enzymes activity of CAT, POD, SOD was 2.1, 10.8, and 40.6 mol h-1 kg-1 respectively, but 21.1 mol h-1 kg-1 PPO was restrained in the treated group. In conclusion, the results provided a reliable method for inhibiting cold injury and explained the internal molecular mechanism of the fruit regulated by calcium. PRACTICAL APPLICATIONS: Refrigerated storage is an important method for extending the storage time of Chinese winter jujube fruit. However, cold damage may occur when the jujubes are stored at low temperature for long-term. It is, therefore, of great significance to find a new method and reveal the molecular mechanism. We believe that our study makes a significant contribution to the literature because it provides an effective method of maintaining higher quality and mechanistic insights into the resistance against the chilling stress of jujubes.

[Self-made metal freezing plate for cryopreservation of human epididymal sperm: An experimental study].

OBJECTIVE: To study the effect of a new human sperm freezing method on the sperm recovery rate and search for an optimal method for cryopreservation of human epididymal sperm. METHODS: We collected semen samples from 76 men with obstructive azoospermia by percutaneous epididymal sperm aspiration and divided each sample into two parts to be cryopreserved with a self-made metal freezing plate (the experimental group) or by slow freezing (the control group), respectively. We measured the percentage of progressively motile sperm (PMS) with the computer-assisted semen analysis system and compared the membrane function, DNA fragmentation index (DFI), acrosin activity and morphological abnormality of the sperm between the two groups before and after cryopreservation. RESULTS: After thawing, both the percentages of PMS and hypotonically swollen sperm were significantly higher in the experimental than in the control group (ï¼»12.0 ± 7.5ï¼½% vs ï¼»8.0 ± 5.1ï¼½%, P < 0.05; ï¼»22.0 ± 17.5ï¼½% vs ï¼»18.0 ± 20.5ï¼½%, P < 0.05), though both decreased in comparison with the pre-freezing parameters (ï¼»20.7 ± 8.8ï¼½% and ï¼»30.0 ± 13.5ï¼½%) (P < 0.05). The sperm acrosin activity was remarkably higher in the experimental than in the control group after thawing (ï¼»75.2 ± 9.5ï¼½ vs ï¼»55.7 ± 8.3ï¼½ µIU/106sperm, P < 0.05), though decreased as compared with the baseline (ï¼»120.0 ± 10.5ï¼½ µIU/106 sperm, P < 0.05). No statistically significant differences were observed between the experimental and the control groups after thawing in the percentage of morphologically abnormal sperm (ï¼»98.7 ± 8.8ï¼½% vs ï¼»98.5±9.2ï¼½%, P > 0.05) or sperm DFI ï¼»38.2 ± 8.5ï¼½% vs ï¼»39.5 ± 10.2ï¼½%, P > 0.05), though both markedly elevated in comparison with the pre-freezing parameters (ï¼»97.2 ± 9.5ï¼½% and ï¼»30.8 ± 9.7ï¼½%) (P < 0.05). The post-thaw recovery rate of sperm was significantly higher in the experimental than in the control group (ï¼»65.2 ± 12.0ï¼½% vs ï¼»52.3 ± 18.0ï¼½%, P < 0.05). CONCLUSIONS: The self-made metal freezing plate, with its advantages of low cost, high efficiency, and easy operation, can be used as an effective method for cryopreservation of human sperm to achieve a high post-thaw sperm recovery rate, progressive sperm motility, and sperm acrosin activity.

[Purification and identification of recombinant varicella-zoster virus glycoprotein E].

OBJECTIVE: To purify and identify recombinant Varicella-Zoster Virus Glycoprotein E. METHODS: The recombinant plasmid pGEX-VZVgE was induced by isopropyl-beta-D-thiogalactoside (IPTG), the fusion protein was purified with affinity chromatography column; then the purified fusion protein was cleaved by thrombin, and the product's antigenicity was examined by Western blot. RESULTS: The product of pGEX-VZVgE induced by IPTG was separated from the mixture proteins by the affinity chromatography column, the expressed fusion protein's relative molecular mass was about 98 x 10(3). After cleavage, the obtained VZV Glycoprotein E's relative molecular mass was about 72 x 10(3); the purified fusion protein and VZV Glycoprotein E were single band by SDS-PAGE. The available antigenicity of Glycoprotein E was confirmed by Western blot. CONCLUSION: Purification of VZV Glycoprotein E with affinity chromatography is an effective method. It provides a foreground for studies on the application of VZV gE.