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几丁质酶是一类在植物抵抗病原真菌等过程中具有重要作用的蛋白质,为探讨几丁质酶在罗汉果抗根结线虫病中的调控作用,本研究基于南方根结线虫侵染下的罗汉果幼苗根系的转录组测序结果,采用生物信息学技术对筛选到的15个罗汉果几丁质酶基因进行分析。结果表明,15个罗汉果几丁质相关蛋白基因编码的氨基酸序列其N段均有一段信号肽,亚细胞定位在胞外;分子量从27 kDa到37 KDa不等;多数为酸性蛋白。基于氨基酸保守结构域和系统发育关系分析,15个罗汉果几丁质酶分属于GH18和GH19两大家族中的3个组别(Ⅰ、Ⅲ和Ⅳ)的成员,GH18家族成员三级结构预测具有典型的(α/β)_8桶状结构,而GH19家族成员三级结构预测只有α螺旋结构域。这些分析结果可为今后深入研究罗汉果几丁质酶的生物学功能和调控机制提供一定的理论依据,为罗汉果抗根结线虫病育种提供参考。 相似文献
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《广西植物》2015,(6)
罗汉果是我国常用的一种中药,用于治疗干咳、口腔溃疡及便秘等,罗汉果皂苷是罗汉果果实中的主要药效物质,为一类葫芦烷三萜皂苷类化合物。由于个别罗汉果低糖皂苷在罗汉果中含量较低,因而难以对这些皂苷有效地进一步进行代谢或药理等研究。该研究采用RP-HPLC监测50%罗汉果皂苷V的水解过程,并对其水解条件进行正交实验优化其组合,建立了酶水解50%罗汉果皂苷V以获取罗汉果次级皂苷的方法。结果表明:酶水解50%罗汉果皂苷V获得罗汉果皂苷ⅢE、Ⅲ、ⅣE和赛门苷I等次级皂苷的最佳水解条件是p H值为5.6的乙酸-乙酸钠缓冲体系,反应温度为55℃,β-葡聚糖酶活性浓度为40万U·L-1,罗汉果皂苷V的反应浓度为0.2 g·L-1,水解时间为10 h。经多次验证,该水解条件重现性好,可用于从50%罗汉果皂苷V中水解制备罗汉果皂苷ⅢE、Ⅲ、ⅣE和赛门苷I等罗汉果皂苷。该研究结果为进一步水解其他罗汉果次级皂苷提供了依据。 相似文献
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罗汉果是我国常用的一种中药,用于治疗干咳、口腔溃疡及便秘等,罗汉果皂苷是罗汉果果实中的主要药效物质,为一类葫芦烷三萜皂苷类化合物。由于个别罗汉果低糖皂苷在罗汉果中含量较低,因而难以对这些皂苷有效地进一步进行代谢或药理等研究。该研究采用RP-HPLC监测50%罗汉果皂苷V的水解过程,并对其水解条件进行正交实验优化其组合,建立了酶水解50%罗汉果皂苷V以获取罗汉果次级皂苷的方法。结果表明:酶水解50%罗汉果皂苷V获得罗汉果皂苷IIIE、III、IVE和赛门苷I等次级皂苷的最佳水解条件是pH值为5.6的乙酸-乙酸钠缓冲体系,反应温度为55 ℃,β-葡聚糖酶活性浓度为40万U·L-1,罗汉果皂苷V的反应浓度为0.2 g·L-1,水解时间为10 h。经多次验证,该水解条件重现性好,可用于从50%罗汉果皂苷V中水解制备罗汉果皂苷IIIE、III、IVE和赛门苷I等罗汉果皂苷。该研究结果为进一步水解其他罗汉果次级皂苷提供了依据。 相似文献
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罗汉果醇是罗汉果皂苷的苷元,有研究报道罗汉果皂苷V具有防癌抑癌作用。该研究采用噻唑蓝实验( MTT法)检测罗汉果醇对不同肿瘤细胞增殖的抑制情况,以及不同浓度的罗汉果醇对CNE1细胞的增殖抑制率;应用细胞克隆形成实验进一步验证罗汉果醇对CNE1细胞增殖的抑制作用;采用Annexin V/PI 双染法检测罗汉果醇对CNE1细胞凋亡的影响;以实时定量PCR技术检测罗汉果醇对CNE1细胞中Caspase-3、Sur-vivin、Bax和Bcl-2基因的mRNA 表达水平的影响。结果表明:罗汉果醇能显著抑制DU145、HepG2、A549、CNE1、CNE2细胞的增殖,其中对CNE1细胞增殖的抑制作用最为显著,并呈剂量依赖性,其半数抑制浓度IC50为(81.48±4.73)μmol·L-1;通过对CNE1细胞进一步的克隆形成实验,也验证了这一点;Annexin V/PI 双染法可见随着浓度的增加,凋亡比例增加;实时定量PCR技术检测显示罗汉果醇处理后,促凋亡基因Caspase-3、Bax的表达增加,抗凋亡基因Survivin、Bcl-2的表达减少。因此,罗汉果醇可能是通过促进Caspase-3、Bax等促凋亡基因和抑制Survivin、Bcl-2等抗凋亡基因的表达,来诱导肿瘤细胞凋亡,进而发挥抗肿瘤活性。 相似文献
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该研究以罗汉果品种“永青1号”为材料,在果实发育后期进行不同强度的遮荫处理,测定遮荫处理下果肉组织中罗汉果苷各组分含量、各种糖分的积累及其相关糖代谢酶活性、叶片光合特性的变化。结果表明:重度遮荫(70%遮荫)会导致果实中罗汉果甜苷Ⅴ含量显著提高,遮荫60 d(授粉后90 d),对照与70%遮荫处理果实中罗汉果甜苷Ⅴ含量分别为4.83%、5.79%,差异达极显著水平( P<0.01);70%遮荫处理下果实中葡萄糖、果糖含量也明显高于对照( P<0.05)。与罗汉果甜苷Ⅴ、葡萄糖、果糖含量的变化不同,遮荫60 d,70%遮荫处理下罗汉果果实中可溶性糖、蔗糖的含量分别显著(P<0.05)和极显著(P<0.01)低于对照。另外,遮荫处理导致罗汉果叶片净光合速率下降,遮荫40 d,70%遮荫处理下叶片的净光合速率显著低于对照( P<0.05)。综上说明,重度遮荫处理可以引起罗汉果果实品质的改变;光合速率下降是遮荫处理下可溶性糖含量降低的主要原因;SPS、AI、SSC活性的改变则是遮荫导致蔗糖含量降低及葡萄糖、果糖含量上升的重要因素;重度遮荫条件下,荫棚中温度降低可能是罗汉果果实中甜苷Ⅴ含量增高的关键诱因。该研究结果为罗汉果的生产及品质调控提供了理论依据。 相似文献
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Nicol JM Elekçioğlu IH Bolat N Rivoal R 《Communications in agricultural and applied biological sciences》2007,72(3):677-686
The Cereal Cyst Nematodes (CCNs) are a group of several closely related species which have been documented to cause economic yield loss on rainfed wheat production systems in several part of the world including North Africa, West Asia, China, India, Australia, America and several countries in Europe. The most commonly reported species is Heterodera avenae, however there are at least two other species H. filipjevi and H. latipons are implicated. It is well appreciated that plants under water and nutrient stress suffer greater yield loss. Control of CCNs requires maintaining nematode populations below economic thresholds. Chemicals are not environmentally sustainable or economic and the major emphasis on control has been with host genetic resistance applied with other integrated pest managent options. Unfortunately due to the number of species and pathotype variation genetic control of Cereal Cyst Nematode with plant resistance is complex. Turkey is one of the top ten wheat producers in the world and has identified these nematode as a major biotic constraint in their rainfed wheat systems. In 2001 a new joint intiative was established between CIMMYT International, the Turkish Ministry of Agriculture and (Ukurova University in Adana to understand i) the distribution of cereal nematodes on wheat; ii) assess the economic importance and improve our understanding of the population dynamics iii) culture, screen and assess known sources of resistance and identify new sources to both groups of nematodes; iv) integrate new sources of resistance into bread wheat cultivars for Turkey and International germplasm using conventional and molecular tools; v) investigate other integrated control options such as rotation and different wheat management strategies and finally vi) capacity build scientists to work in this important area. Some highlights of this work will be presented and the newly formed ICCNI - International Cereal Cyst Nematode Initative introduced. 相似文献
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Nursery blocks (48 dogwood, 27 maple, 17 peach) in 20 middle Tennessee nurseries were sampled for nematodes in March,July, and October 1981. Dogwoods and maples were grouped in three age classes: 1-2, 3-5, and 10+ years. Nematodes were extracted from soil samples, counted, and assigned to trophic groups as follows: plant parasites, microbivores, fungivores, predators, and omnivores (= Dorylaimida). Total nematode numbers per 200 cm s soil ranged from 52 to 9,166 (mean = 1,785 ± 1,420). Nematodes were more abundant in dogwood and maple than in peach blocks, and their numbers were significantly correlated with percentage of weed ground cover and number of weed species. Nematode numbers in dogwood sites were also correlated with dogwood age. Microbivores were the most abundant trophic group in all sites, followed by plant parasites, fungivores, omnivores, and predators. Nematode communities in nursery sites shared characteristics of both undisturbed and agricultural habitats. Degree and diversity of plant ground cover appeared to be the most important factors determining nematode community structure. 相似文献
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Abstract: Optimal conditions for cryopreserving of populations of root lesion nematode (Pratylenchus spp.) were determined. Nematode survival was achieved using glycerol pre-treatments in the range of 14-17% (w/w). Increasing duration of the incubation in glycerol (up to 5 days) before immersion in liquid nitrogen significantly influenced nematode survival The highest mean survival for P. thornei was 76% after incubation in glycerol for 5 days. Nematodes were able to reproduce and infect carrot disc cultures after cryopreservation. This technique has valuable applications for long-term germplasm storage and maintenance of genetic lines. 相似文献
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A. E. MacGuidwin 《Journal of nematology》1989,21(3):409-415
The abundance of Pratylenchus scribneri in soil and root habitats was compared in potato and corn plots during 1986-88. Nematodes were extracted from 100-cm³ soil samples and the roots contained within the samples. The percentage of the population recovered from soil, similar among years and crops, averaged ca. 50% at the beginning and end of the growing season and ca. 20% from early to late season. Proportionately more adults and fourth-stage juveniles than younger stages were located outside roots until harvest. In a related study, nematodes were isolated from the roots, root surfaces, and soil associated with roots of whole corn and potato plants sampled from the field. Nematode population estimates calculated from the whole plant samples were generally lower than those based on soil cores, but showed similar patterns of population growth. Nematode density per gram dry weight was highest in roots, intermediate on root surfaces, and lowest in soil. Estimates of the absolute abundance of nematodes in each of the three habitats were highest in roots or soil, depending on the sampling date, and lowest on root surfaces. This study demonstrates that P. scribneri inhabits soil environments even when host roots are present and illustrates the importance of considering all possible habitats when estimating the size of Pratylenchus spp. populations. 相似文献