本研究通过设置不同浓度的脱氢乙酸钠（SD）（0即对照、0.01、0.1和1.0 mmol L^-1），研究SD延长‘巨峰’葡萄货架期的效果。结果表明0.01 mmol L^-1的SD对于延长‘巨峰’葡萄的货架期效果最好。与对照相比，0.01 mmol L^-1 SD处理的‘巨峰’葡萄果实失重率、褐变指数、过氧化氢（H₂O₂）和丙二醛含量（MDA）显著降低，且好果率、果实硬度、总可溶性固形物含量、抗坏血酸含量和超氧化物歧化酶（SOD）活性均显著升高。此外，甲基化敏感扩增多态性（MSAP）检测结果表明，0.01 mmol L^-1 SD处理后，‘巨峰’葡萄的DNA甲基化水平显著高于对照。综上，0.01 mmol L^-1 SD可用于延长‘巨峰’葡萄的货架期。本研究结果还揭示了葡萄贮藏过程中活性氧（ROS）代谢与DNA甲基化水平变化之间的密切联系。

To characterize the β-lactam resistance in veterinary clinical isolates of Haemophilus parasuis, 115 isolates were examined for the β-lactam resistance, the possession of β-lactamase, and the presence of β-lactamase genes. The genetic relationship among isolates was evaluated by pulsed-field gel electrophoresis (PFGE). Overall, the commonly detected resistance phenotypes were resistant to ampicillin (26.09%), penicillin (22.61%), amoxicillin (21.74%), cefazolin (14.78%), cefaclor (12.17%), and cefotaxime (6.96%). These strains showed high minimal inhibitory concentration (MICs) to oxacillin. 20.87% strains produced β-lactamase, and 4.35% strains showed extended-spectrum b-lactamase (ESBL) phenotype. Moreover, 19 strains harboured bla genes including TEM-1 (n=5), TEM-116 (n=10), and ROB-1 (n=5). Significantly, one strain possessed both TEM-1 and ROB-1, and displayed resistance to cefotaxime (MIC=8 mg L-1). The epidemiological analysis of PFGE revealed high genetic diversity among bla-positive isolates. This work shows that TEM- and ROB-type β-lactamases are prevalent in H. parasuis isolates in China.