病原菌对Strobilurin类杀菌剂抗药性机理的研究进展

结合strobilurin类杀菌剂作用机制的特点,通过室内和田间研究的结果总结了病原菌对该类杀菌剂产生抗药性的主导机制。Strobilurin类杀菌剂主要结合于病原菌细胞色素bc1复合物中细胞色素b部分的Qo位点,而细胞色素b由突变率很高的线粒体基因组编码,所以病原菌很容易因该基因的突变而导致抗药性发生。至今已至少有14种寄主植物上的25种病原菌在田间表现出了对strobilurin类杀菌剂的抗药性。抗药性产生的主要机理是病原菌细胞色素b的氨基酸残基发生了单点取代。田间抗性菌株的主要取代位点是G143A、F129L和G143R。一些非靶标生物细胞色素b的143位为丙氨酸,这可能是strobilurin类杀菌剂对其表现安全性的原因之一。由于锈病病菌Puccinia spp.中内含子剪切位点恰好出现在编码G143的GGT之后,G143A的突变会导致突变菌株的死亡,因而它们在田间不会表现出抗药性。此外,Qo抑制剂阻断电子传递后会导致胞内活性氧(ROS)的增加,而ROS可以诱导细胞交替氧化酶(AOX)的表达,进而启动线粒体的旁路氧化途径,使病原菌表现出抗药性。因此,病原菌氨基酸残基的单点取代和交替氧化途径是导致病原菌对strobilurin杀菌剂产生抗药性的主导机制。     

l‐DOPA inhibited the root growth of lettuce by inducing reactive oxygen species generation

l ‐3,4‐dihydroxyphenylalanine (l ‐DOPA) is a bioactive natural compound that inhibits the growth of several plant and weed species. However, its mode of action is not yet well understood in plants. The present study was conducted to explore the mechanism of growth inhibition by l ‐DOPA in lettuce (Lactuca sativa L.). The results revealed that l ‐DOPA induced cell death and inhibited the root growth of lettuce. Moreover, 0.1 mmol L^–1 l ‐DOPA enhanced the polyphenol oxidase activity, production of reactive oxygen species ( and H₂O₂) and lipid peroxidation in the lettuce roots. The results suggest that l ‐DOPA‐induced growth inhibition in lettuce roots might be related to oxidative stress.     

干旱胁迫下甘蔗叶类黄酮及相关酶活性的变化

以两个抗旱性不同的甘蔗品种ROC22和ROC16为试材,采用聚乙二醇模拟干旱胁迫,研究了甘蔗幼苗在干旱胁迫下叶片中类黄酮含量及相关酶活性的变化.结果表明,与对照相比,10% PEG胁迫2 h至14 h,耐旱性强的ROC22品种类黄酮含量降低,耐旱性弱的ROC16品种类黄酮含量先降后升;2个品种幼苗叶片中苯丙氨酸解氨酶活性呈现先降低后升高的变化规律.ROC22叶片多酚氧化酶活性呈先升后降的变化,ROC16叶片多酚氧化酶活性下降;2个品种甘蔗叶过氧化物酶活性持续下降.     

李果实发育过程中果皮色素、糖和总酚含量及多酚氧化酶活性的变化

大石早生、龙园秋李、黑宝石、安哥诺4个李品种在果实发育过程中,果皮叶绿素、类胡萝卜素、总酚以及类黄酮含量呈下降趋势,可溶性总糖、蔗糖、果糖、葡萄糖、花青苷含量及多酚氧化酶(PPO)活性逐渐增加。除安哥诺的蔗糖、葡萄糖外,果皮花青苷与不同种类糖含量之间呈显著正相关或极显著正相关,大石早生蔗糖含量与花青苷含量呈极显著正相关,相关系数为0.9688,龙园秋李、黑宝石则呈显著正相关,相关系数分别为0.9481、0.9447;黑宝石、安哥诺果糖与花青苷含量呈显著正相关,相关系数分别为0.9358、0.8925,大石早生、龙园秋李则呈极显著正相关,相关系数分别为0.9438、0.9763;大石早生、龙园秋李、黑宝石果皮葡萄糖与花青苷含量呈显著正相关,相关系数分别为0.8940、0.9022、0.9424。龙园秋李、黑宝石这2个品种果皮总酚含量与PPO活性呈极显著负相关,相关系数分别为-0.9896、-0.9664。     

小菜蛾幼虫对拟除虫菊酯类杀虫剂的抗药性与多功能氧化酶的关系

作者就上海梅陇、广州天河和江西莲塘的小菜蛾对拟除虫菊酯的抗药性及其与微粒体多功能氧化酶(MFO)的关系进行了研究。结果表明,上海种群(R)对溴氰菊酯、氰戊菊酯和氯菊酯的 LD_(50)分别是江西种群(S)的>10414倍、2102倍和245倍。广州种群分别为>10414倍、>3569倍和1533倍。活体增效试验表明,酯酶抑制剂 TBPT 在低剂量(0.208μg/虫)时,对溴氰菊酯和氯菊酯都无增效作用,在高剂量(2.08μg/虫)时分别增效41.7倍和110倍。用 MFO的抑制剂 PB 作同样处理时,低剂量的 PB 对溴氰菊酯和氯菊酯的增效作用分别为5倍和12.9倍;高剂量的 PB 对溴氰菊酯增效562倍以上。~(14)C-氰戊菊酯代谢的离体研究结果表明,R 小菜蛾代谢~(14)C-氰戊菊酯的速度是 S 小菜蛾的2.1倍,TBPT 抑制~(14)C-杀灭菊酯的代谢约20%,而PB 抑制50%以上。由此可以得出结论,MFO 是小菜蛾对拟除虫菊酯的主要机理之一。     

卡特兰ACC氧化酶cDNA片断的克隆与序列分析

以卡特兰(Cattleya)花朵为试材,首先提取总RNA,并根据其它兰花的ACC氧化酶(1-aminocyclopropane-1-carboxylic acid oxidase,ACO)基因保守序列设计1对特异性引物,然后通过RT-PCR法,克隆得到一条卡特兰ACC氧化酶的cDNA片断,该片断长度为967 bp,共编码321个氨基酸残基。序列分析结果显示该克隆片断与已发表的其它兰花的ACC氧化酶基因序列同源性很高,均在85%以上,尤其与其近亲C.bicolor、C.inter-media、Laelia anceps的同源性均在95%以上。     

初榨橄榄油中多酚化合物的UPLC-FLD检测及其抗氧化活性研究

采用超高效液相色谱荧光检测法(UPLC-FLD)检测不同品种初榨橄榄油中6种多酚化合物的含量,并测定样品的总多酚含量及抗氧化活性,同时对多酚组分与抗氧化能力的相关性进行分析.结果表明:色谱条件为采用Cadenza色谱柱(150 mm×4.6 mm,5μm),柱温35℃,以0.1％甲酸-水(A)-乙腈(B)为流动相进行梯...     

葡萄糖氧化酶的微生物发酵生产工艺研究

葡萄糖氧化酶作为一种重要的氧化还原酶,在饲料、畜牧等行业应用广泛,可用于改善动物饲料的消化利用率。本文对葡萄糖氧化酶的发酵生产工艺、提取纯化工艺、酶学特性改进工艺及质量控制工艺作了简单介绍,以期为葡萄糖氧化酶的工业化生产和应用提供帮助。     

Effect of Qushi-Dizhuo decoction on urate transporters in hyperuricemia rats

AIM:To investigate the effects of Qushi-Dizhuo decoction (QSDZ) on the expression of uric acid transporters in rats with hyperuricemia. METHODS:Male Sprague-Dawley rats (n=60) were randomly divided into blank control group, model group, allopurinol group, and low-, middle- and high-dose QSDZ groups, with 10 rats in each. Except the blank control group, rats in the other groups were treated with adenine and potassium oxonate to prepare hyperuricemia rat model by intragastric administration once a day. Meanwhile, the rats in treatment groups were intragastric admi-nistrated with the corresponding preparation, after 28 days of continuous administration, the rats were sacrificed. Serum uric acid (UA) and creatinine (Cr) levels and xanthine oxidase (XOD) activity were measured. The morphological changes of renal tissues were observed by HE staining. The protein and mRNA expression of urate transporter1 (URAT1), glucose transporter 9 (GLUT9) and organic anion transporter 1 (OAT1) were detected by Western blot and real-time PCR. ATP-binding cassette subfamily Gmember 2 (ABCG2) and organic cation transporter 1 (OCT1) were also determined. RESULTS:Compared with the blank control group, the content of UA and Cr and the activity of XOD were significantly increased (P<0.05), the URAT1 and GLUT9 protein levels were significantly up-regulated, and the OAT1, ABCG2 and OCT1 protein levels were significantly down-regulated in model group (P<0.05). Compared with model group, the levels of serum UA and Cr and actioity of DXD were significantly decreased in QSDZ middle,high-dose group (P<0.05). The protein levels of URAT1 and GLUT9 were decreased, while the protein levels of OAT1, ABCG2 and OCT1 were increased in middle- and high-dose groups compared with model group (P<0.05). The mRNA expression of URAT1, GLUT9, OAT1, ABCG2, OCT1 was consistent with its protein expression trend. CONCLUSION:QSDZ decoction may through inhibiting the activity of XOD and regulating the expression of transporter to show its anti-hyperuricemia effect.     

Response of health-promoting bioactive compounds and related enzyme activities of table grape (Vitis vinifera L.) to deficit irrigation in greenhouse

Grape (Vitis vinifera L.) containsabundant secondary metabolites that are beneficial to humanhealth. Previous studies reported that deficit irrigation alters fruitcomposition, however, the mechanisms underlying the responseof health-promoting bioactive compounds to deficit irrigation indifferent phenological stages and those of associated metabolismrelatedenzymes remain unclear. Continual maintain irrigation (CI),deficit irrigation throughout growth seasons (DI), deficit irrigationbefore (ED) and after (LD) fruit set were performed for investigatingthe response of bioactive compounds and related enzyme activitiesin grape berries to deficit irrigation. Resveratrol, anthocyanins,phenylalanine ammonialyase (PAL) and superoxide dismutase(SOD) in grape berries were increase in DI, ED and LD treatments,whereas proanthocyanidins and polyphenol oxidase (PPO) weresignificantly increased in CI treatment. Significant differenceswere observed between the groups with respect to resveratrol,anthocyanins and PAL activity. Grapevine evapotranspirationwere decreased in ED and LD treatments, with water useefficiency increased. Principal component analysis showed a clearseparation among four treatments, and the LD had the highesttotal membership function value. Changes of bioactive compoundscontent can be attributed to PAL activity. Deficit irrigation after fruitset can promote the production of functional and superior qualitytable grape in greenhouse.