草莓果实采后衰老过程中能量代谢的变化

以‘红颜’草莓果实为试材,研究了果实采后衰老过程中线粒体呼吸相关酶活性及能量水平的变化,以了解能量与草莓果实衰老的关系。结果表明:随着草莓果实的衰老,草莓果实线粒体琥珀酸脱氢酶(SDH)、H+-ATPase和Ca2+-ATPase活性均明显下降,细胞色素氧化酶(CCO)活性上升;三磷酸腺苷(ATP)含量持续下降,二磷酸腺苷(ADP)和磷酸腺苷(AMP)含量上升;ATP、ADP、AMP 3种能量物质含量差异明显,其中ATP含量远高于ADP和AMP含量,ATP含量代表了草莓果实中的能量水平,且能荷(EC)与ATP协同变化;试验表明,草莓果实衰老与线粒体呼吸相关酶活性下降、线粒体功能下降而导致的能量不足有关。     

Ca~(2+)-ATPase抑制剂对采后草莓呼吸速率和花青苷含量的影响

用Ca2+-ATPase抑制剂钒酸钠(SO)和曙红(EB)浸泡处理转红期草莓果实(cv.Darselect)后表明,2者能提高果实呼吸速率,迅速促进外层果肉的花青苷生成,增加其可溶性糖含量,髓部果肉的花青苷生成和可溶性糖的变化较慢,而对果实的失重率影响不大。因此,Ca2+-ATPase抑制剂具有促进果实成熟衰老的作用。     

锦橙叶片POD动力学研究

以锦橙成熟春梢叶片提取过氧化物酶 (POD) ,分别测定了该酶的最适pH、最适温度及酶促动力学参数Km值和Vmax值 ,比较分析了常见几种POD抑制剂的作用程度。结果表明 :以邻甲氧基酚为底物 ,叶片POD的最适pH为 5 .0 ,最适温度为 32℃ ,Km值为 2 8.0 4mmol/L ,Vmax值为 147.83unit/s·gFW。在所测的 6种抑制剂 (K+、Pb2 +、CN-、Vc、硫脲及L 半胱氨酸 )中 ,CN-,Pb2 +,硫脲和L 半胱氨酸对POD表现出较强的抑制作用 ,K+对POD活性起促进作用。在一定浓度范围内 ,各种抑制剂的作用程度与其浓度具有极显著的相关性     

红芝组成型漆酶酶学性质的研究

研究了温度、pH值、金属离子和抑制剂对红芝漆酶活性和稳定性的影响,测定该漆酶的Km值和Vmax。结果表明:红芝漆酶最适反应温度为60℃,低于50℃时较稳定;最适pH值为3.0,在pH 2.5~4.0的范围表现出较强的稳定性;Cu2+、Mn2+、Mg2+对酶活有促进作用,而Cr3+、Hg2+、Fe2+和抑制剂EDTA、DMSO、SDS对酶活有抑制作用;以愈创木酚为底物时Km值为0.13 mmol/L,最大反应速率Vmax为234 nmol.mL-1.min-1。     

草莓果实发育过程中糖、pH值及ABA水平变化趋势

为了揭示草莓果实发育和成熟的生理机制,本研究以杜克拉草莓7个时期的果实为试材,分析果实发育过程中pH值、可溶性糖和ABA变化趋势.结果表明,果实发育前期可溶性糖积累以葡萄糖和果糖为主,蔗糖很低;果实进入始熟和成熟,蔗糖分别有一次快速积累的过程,全红时蔗糖含量是果糖和葡萄糖的1.25倍.以纯白期pH值最低点为界,pH值先...     

香菇中γ-谷氨酰转肽酶的分离纯化及其酶学性质研究

通过(NH4)2SO4沉淀、Phenyl Sepharose FF疏水层析分离纯化香菇中的γ-谷氨酰转肽酶(γ-Glutamyltranspeptidase,GGT),纯化后的GGT的比活力到达了19.59 U/mg.SDS-PAGE分析表明,GGT由分子量分别为28 kDa和60 kDa的两个亚基组成.酶学性质试验结果表明,GGT反应的最适温度为37 ℃,最适pH 值为7.6;金属离子Na+、K+和Ca2+对酶有激活作用,而Ag+、Cu2+、Zn2+和Fe3+则有抑制作用;试验范围内,GGT水解γ-glutamyl-p-nitroanilide的米氏动力学参数Km 值为2.601 μmol/mL,Vmax值为0.0287 μmol/min;组成的氨基酸中,Glu和Asp含量较高,Met和Cys含量较低.     

蜜柚多酚氧化酶的酶学特性与活性测定研究

以邻苯二酚为底物,采用分光光度法在420nm处测定蜜柚多酚氧化酶(PPO)的活性,研究底物浓度、pH、温度及酶液浓度对PPO活性的影响,并建立了酶促褐变反应动力学方程。结果表明:蜜柚多酚氧化酶的酶促反应符合米氏方程所描述的单底物酶促反应动力学,以邻苯二酚为底物的最大反应速度为:Vmax=22.452U/min,Km=128.2mmol/L。蜜柚多酚氧化酶作用的最适pH6.4,最适温度为10℃。不同时间的蜜柚多酚氧化酶的平均活性呈逐渐下降的趋势。     

草莓成熟过程中NAD激酶、NADP磷酸酶活性

 研究了‘春星’草莓果实成熟时NAD 激酶、NADP 磷酸酶活性及NAD 激酶部分特性。结果表明, NAD 激酶和NADP 磷酸酶活性在果实绿色期到乳白期升高, 粉红期下降, 全红期又再次升高。NAD 激酶可被Ca²⁺ 强烈抑制, 被EGTA (Ca²⁺专一性螯合剂) 激活。随着成熟进程, NAD 激酶对ATP 的依赖性增加。     

库源关系对草莓叶片光合磷酸化和Rubisco活性的影响

以温室草莓为试材,研究库源关系对叶片光合磷酸化和Rubisco活性的影响,以提高草莓叶片光合作用和果实品质.结果表明:提高草莓的负载量,可显著提高叶片净光合速率、叶绿素含量,同时,叶片中可溶性蛋白、Rubisco活性、Hill反应活性、光合磷酸化活性、ATPase活性也得到显著提高.所有处理叶片净光合速率与Rubisco活性和Ca2+ -ATPase呈显著正相关,在高负载量下净光合速率与叶绿体活性显著性升高.提高负载量能提高草莓单株产量,但是降低了果实品质,在宁夏,每株草莓留4个果实其产量和品质均较好.因此,设施条件下,负载量主要是通过调节叶片中Rubisco和叶绿体活性来影响叶片光合作用,最终调节草莓产量和果实品质.     

草莓果实成熟期花青苷、酚类物质和类黄酮含量的变化

以春星和全明星为试材,研究了不同成熟度草莓果实酚类物质、类黄酮及花青苷的动态变化。结果表明,随着果实的成熟,酚类物质和类黄酮在绿熟期有较高的含量,之后随着果实的成熟先下降,至紫红期又开始大量积累;花青苷含量随着果实的成熟逐渐增加,紫红期达最大值;低温贮藏的草莓果实酚类物质、类黄酮含量首先下降,之后随着贮藏天数的增加而不断上升;花青苷含量逐渐增加,但增加的趋势比较缓慢。     

Effects of prearuptorin C on myocardial ATPase activity and app arent Km and Vmax in spontaneously hypertensive and renovascular hypertensi ve rats

AIM:To study the effects of prearuptorin C (Pra-C) on myocardial sarcolemma Na+,K+-ATPase activity,myocardial mi tochondria Na +,K+-ATPase,Ca2+-ATPase,Mg2+-ATPase activities and apperent Km an d Vmax in spontaneously hypertensive (SHR) and renovascular hypertensive rats (R HR).METHODS:ATPase activity was measured with colourmetric method.Apparent Km and Vmax of both Na+,K+-ATPase in myocardial sarcolemma and Ca 2+-ATPase in myocardial mitochondria were calculated according to Lineweav en-Burk double-reciprocal plot method with liner regression.RESULTS:The Vmax of both Na+,K+-ATPase in myocardial sarco lemma and Ca2+-ATPase in myocardial mitochondria were lower in SHR untrea ted group than that in SD control rats,while Km was higher than that in SD cont rol rats.In RHRs untreated group,only Vmax was decreased,while the Km had no statistically change.Pra-C prevented the reduction of ATPase in amount,but no t affected their intrinsic characteristics.CONCLUSIONS:The results suggest that both amounts and affinitie s to ATP of Na+,K+-ATPase and Ca2+-ATPase were decreased in SHRs,but in RHRs,only amounts of ATPase was decreased,while their affinities to ATP we re unchanged.Treatment with Pra-C prevents the decrease in amount of ATPase.     

柑橘全爪螨Na+-K+-ATPase的生化毒理学特性研究

为明确柑橘全爪螨Na+-K+-ATPase与其抗药性之间的关系,采用微量滴度酶标板法对柑橘全爪螨敏感品系(SS)、甲氰菊酯抗性品系(FeR)和阿维菌素抗性品系(AvR)的Na+-K+-ATPase的生化毒理学特性进行了比较研究.结果表明,柑橘全爪螨Na+-K+-ATPase比活力从高到低依次为AvR、SS和FeR;柑橘...     

番茄果实采后NAD激酶活性与活性氧代谢的关系

以粉红期番茄 (Lycopersicon esculentum Mill.) 果实为试材,研究了采后果实在4℃和20℃下贮藏期间成熟衰老过程中NAD激酶（NADK,nicotinamide asenine dinucleotide kinase）活性及其底物NAD（H）、产物NADP（H）以及超氧阴离子、过氧化氢（H₂O₂）、丙二醛（MDA）含量的变化,并分析了其相互关系。结果表明,番茄果实在4℃贮藏时,NADK受到激活,贮藏前期活性比后期高;在20℃贮藏时,NADK除了在贮藏后期出现一个高峰外,整个贮藏期活性比4℃的低;NAD（H）含量的变化趋势与NADK活性的变化趋势相反。4℃贮藏的NADP（H）含量高于20℃下贮藏的,贮藏前期高于贮藏后期;同时,在4℃贮藏期间果实超氧阴离子生成速率、H₂O₂含量、膜氧化产物MDA含量以及番茄红素含量均比20℃贮藏的低,说明低温在延缓果实衰老的同时激活了NADK活性,NADK可能通过影响NAD（H）、NADP（H）的含量及比例来调控超氧阴离子生成速率和H₂O₂含量,从而调控番茄果实的成熟衰老。     

Physiological changes in boysenberry fruit during growth and ripening

Summary

Boysenberries (Rubus hybrid) were harvested at five developmental stages (green, “turning”, pink, red and purple) to study changes associated with flavour, colour and firmness, with a particular focus on the different enzymes involved in chlorophyll degradation or cell wall degradation. The level of reducing and non-reducing sugars increased 109- and 52-fold, respectively, between the “turning” and the purple stage. Titratable acidity increased by 84% between the green and the pink stage, but dropped by 41% between the red stage and full ripening. Total phenols displayed their highest values in green and “turning” fruit. Chlorophyll a and b degradation occurred mainly during the early stages of development, and was paralleled by a 2.3-fold increase in chlorophyllase activity and a 5-fold increase in Mg-dechelatase activity between the green and the red stages. Chlorophyll peroxidase activity was high at the green stage, but did not change significantly after the “turning” stage. This is the first report on the activity of chlorophyll-degrading enzymes in Rubus spp. fruits. Anthocyanins increased 11-fold between the “turning” and the pink stages, and an additional eight-fold between the pink and the purple stages. Fruit firmness decreased noticeably during ripening, with a concomitant 10.75-fold increase in polygalacturonase activity, beginning at the “turning” stage. Endo- -1,4-glucanase and -galactosidase activities rose 9.2- and 6.7-fold, respectively, after the pink stage and paralleled the major softening process taking place between the pink and purple stages, when fruit firmness decreased from 3.83 N to 0.29 N. Pectin methylesterase activity was high in pink and red fruit, but decreased by 21% as the fruit turned from red to purple. This is the first report on cell wall enzyme activities whose combined action might be required for the breakdown of natural cell wall substrates during ripening in boysenberry, as happens in other soft fruits.     

脂氧合酶与番茄采后成熟的关系

采后番茄果实组织的脂氧合酶（ＬＯＸ）活性随成熟衰老期的进程而改变，从绿熟期（ＭＧ）到转红期（Ｔ）ＬＯＸ酶的活性逐渐增高，然后降低，其模式呈现跃变型果实的特点。利用外源乙烯分别处理绿熟期、发白期和转红期的果实，其ＬＯＸ酶的活性较对照都有明显提高。用ＬＯＸ酶处理番茄果实组织，乙烯产量没有明显提高，然而电导率有大幅度增加，二羟基萘（ＤＨＮ）能部分抑制ＬＯＸ酶的这一作用。ＬＯＸ酶的活性增加需要有果蔬体内乙     

Effects of phospholamban antisense RNA on SR Ca2+-ATPase and ［Ca2+］i in rat cardiomyocytes by adeno-associated virus vector

AIM: To investigate the effect of phospholamban antisense RNA (asPLB) on the activity of sarco-endoplasmic reticulum (SR) Ca2+-ATPase, and the change of intracellular free Ca2+ concentration (［Ca2+］i) in rat cardiomyocytes by adeno-associated virus(AAV) vector. METHODS: rAAV-asPLB and rAAV-LacZ were constructed by AAV Helper-Free System. RT-PCR and Western blotting were used to determine the mRNA and protein expression of PLB. The activity of SR Ca2+-ATPase and the ［Ca2+］i were measured. RESULTS: Compared to controls, the PLB mRNA and protein expression reduced in rat cardiomyocytes transfected with rAAV-asPLB. The activity of Ca2+-ATPase was increased. In rest state, the level of ［Ca2+］i in rAAV-asPLB transfected group was decreased. The level of ［Ca2+］i was increased when induced by isoproterenol. CONCLUSION: rAAV-asPLB vector disrupts the expression of PLB, enhances the activity of Ca2+-ATPase, reduces the resting ［Ca2+］i and enhances the isoproterenol-induced ［Ca2+］i.