杂交构树叶多酚提取工艺优化及其抗氧化活性研究

为建立和优化杂交构树叶多酚的提取工艺,本试验采用超声波辅助提取的方法,以构树叶多酚得率为考察指标,通过单因素试验研究液料比、乙醇浓度、超声时间、超声温度4个因素对构树叶多酚得率的影响;在单因素试验的基础上,借助响应面法设计4因素3水平的试验方案,对构树叶多酚提取的工艺参数进行优化,建立回归模型并进行响应面分析,最终确定最佳的提取工艺参数,并进行3次平行验证;以维生素C为对照,通过测定构树叶多酚对DPPH和ABTS自由基的清除率,评价构树叶多酚的体外抗氧化活性。结果显示：4个因素对构树叶多酚得率的影响顺序依次为：乙醇浓度（B） > 液料比（A） > 超声温度（D） > 超声时间（C）,响应面分析结果显示：两两因素之间存在交互作用,但交互作用不显著（P>0.05）;在液料比为70：1、乙醇浓度为60%、超声时间为50 min、超声温度50 ℃的条件下,构树叶多酚的得率最大,为13.62 mg/g,与响应面法的预测值接近;体外抗氧化试验结果表明,构树叶多酚可以清除DPPH和ABTS自由基,并且在高浓度情况下可以达到与维生素C相当的水平。综上,试验建立的构树叶多酚提取工艺准确、可行,同时证明构树叶多酚具有良好的抗氧化活性;该结果可为构树叶多酚的生物活性研究以及构树叶的药用价值开发提供参考。     

Evaluation of tizanidine as a marker of canine CYP1A2 activity

The dog CYP1A2 enzyme is likely an important contributor to the metabolism of veterinary drugs. Dog CYP1A2 is expressed in liver, plus it is inducible and polymorphic, creating the potential for intersubject differences in pharmacokinetics. Hence, the ability to probe dog CYP1A2 activity and inhibition is relevant toward veterinary drug development and drug–drug interaction assessment. Previous studies have relied on human probes with questionable specificity for CYP1A2, so it was hypothesized that recombinant CYP1A2 could be used to find a specific CYP1A2 substrate. Intrinsic clearance experiments demonstrated that tizanidine was a substrate of CYP1A2. Profiling of tizanidine metabolites generated by CYP1A2 identified the imidazole metabolite that was detectable in dog plasma. The imidazole metabolite was subsequently used to evaluate tizanidine as a CYP1A2 probe. Co‐administration of the CYP1A inhibitor enrofloxacin with tizanidine significantly decreased (30%; n = 3) the formation of the imidazole metabolite vs. control experiments. As enrofloxacin is a weak inhibitor, further studies are required to confirm the sensitivity of tizanidine as an in vivo probe. However, tizanidine may be a more selective CYP1A2 probe than phenacetin when conducting in vitro studies due to the presence of other phenacetin‐metabolizing enzymes in dog liver microsomes.     

早熟西瓜新品种“红双喜”的选育

"红双喜"是利用优良高代西瓜自交系‘YF8’为母本,‘S9’为父本配制的早熟花皮圆果形西瓜杂交种。早熟、丰产、抗裂果,植株长势稳健,全生育期90d左右,果实发育29~31d。商品瓜高圆形,果实绿色底覆有13~15条不规则墨绿色条带。极易坐果,果肉红色均匀,瓤脆多汁,中心可溶性固形物12%左右,边部9%,品质佳美。皮韧性好,耐贮运,单果质量7kg,667m2产量4 300kg左右。适宜西北5省区保护地及露地栽培。     

黑皮冬瓜嫁接砧木的筛选与鉴定

挑选南瓜砧、蒲瓜砧和葫芦砧共10个品种,以佛山市三水黑皮冬瓜为接穗,采用斜顶插接法嫁接,露地栽培管理,比较其产量和农艺性状。试验结果表明,DZ-01冬瓜砧、京欣砧三号和强势作为三水黑皮冬瓜的嫁接砧木,可有效降低枯萎病发病率,增产10%以上,商品性状得到明显改善,商品品质差异不显著,推广应用性强。     

Dystocia in a Rothschild giraffe leading to a caesarean section

A 9-year-old female Rothschild giraffe (Giraffa camelopardalis rothschildi), weighing approximately 900 kg, at Longleat Safari Park, Wiltshire, UK was presented with dystocia in September 2005. This paper details the surgical and anaesthetic procedures carried out performing a caesarean section to remove a dead male calf and the successful recovery of the giraffe.