拟细羽束梗孢发酵菌丝体中自由基清除活性成分分析

用二苯基苦基苯肼(DPPH)自由基法,首次对拟细羽束梗孢(Isaria gracilioides RCEF3 279)菌丝体的不同溶剂提取物进行了自由基清除活性的定性定量分析,发现其甲醇提取物具有较强的清除自由基活性,当菌丝浓度为10 g/L时,其甲醇提取物的自由基清除率达到了92.4％±0.3％.DPPH自显影-薄层...     

蝉拟青霉代谢产物清除DPPH自由基和抗真菌活性的研究

用二苯代苦味肼基自由基(DPPH)-TLC法和酶标仪法对一株蝉拟青霉P3菌丝体和发酵液甲醇提取物的清除自由基活性进行了定性和定量测定,发现两种提取物具有较强的清除自由基活性,在浓度为5.0mg/mL,于37℃下保温10min时,两种样品对0.4mg/mL的DPPH自由基的清除率分别可达55.52%和74.86%.以一种黑曲霉菌为指示菌,采用薄层色谱法对蝉拟青霉菌丝体和发酵液甲醇提取物进行抑菌活性试验,实验中根据抑菌圈大小判定代谢物抑菌活性的大小.同时,以致病菌白色假丝酵母菌为指示菌,采用牛津杯法对提取物进行进一步抑菌活性验证,结果表明,菌丝体和发酵液提取物样品浓度为5.0mg/mL时,其抑菌圈直径分别可达11.23mm和21.42mm.     

排风藤内生真菌PFT-2发酵产物抗氧化活性研究

采用DPPH·法及Fe3+还原力法对排风藤内生真菌PFT-2提取物的抗氧化活性进行研究,首先测定发酵液乙酸乙酯萃取物和菌丝体甲醇总提物的活性,然后测定菌丝体总提物各极性部位,即石油醚、氯仿、乙酸乙酯、正丁醇,丙酮、甲醇和水层剩余物部位的活性,同时以VC作为阳性对照。结果表明:内生真菌PFT-2菌丝体甲醇总提取物各样品抗氧化活性较强,尤其是甲醇提取物部位、丙酮提取物部位和正丁醇部位;它们对DPPH·的清除作用与Vc相当,其中甲醇提取物部位IC50值为0.023 mg/m L,活性略高于VC,同时以上提取物对Fe3+也具有很强的还原能力。     

排风藤内生真菌PFT-2发酵产物抗氧化活性研究北大核心CSCD

采用DPPH·法及Fe3+还原力法对排风藤内生真菌PFT-2提取物的抗氧化活性进行研究,首先测定发酵液乙酸乙酯萃取物和菌丝体甲醇总提物的活性,然后测定菌丝体总提物各极性部位,即石油醚、氯仿、乙酸乙酯、正丁醇,丙酮、甲醇和水层剩余物部位的活性,同时以VC作为阳性对照。结果表明:内生真菌PFT-2菌丝体甲醇总提取物各样品抗氧化活性较强,尤其是甲醇提取物部位、丙酮提取物部位和正丁醇部位;它们对DPPH·的清除作用与Vc相当,其中甲醇提取物部位IC50值为0.023 mg/m L,活性略高于VC,同时以上提取物对Fe3+也具有很强的还原能力。     

羽叶千里光不同部位提取物的抗氧化活性研究

目的:比较研究羽叶千里光根、茎、叶和花四个部位甲醇提取物的抗氧化活性.方法:采用索式提取法分别对羽叶千里光根、茎、叶和花进行甲醇提取;采用分光光度法测定提取物对二苯代苦味酰自由基(DPPH)清除能力及其在β-胡萝卜素/亚油酸体系中的抗氧化活性.结果:羽叶千里光叶甲醇提取物对DPPH的清除能力最强,其次为茎、花、根.在β-胡萝卜素/亚油酸体系中,羽叶千里光抗氧化作用强弱依次为叶、茎、根、花.结论:羽叶千里光四个部位甲醇提取物均有抗氧化活性.其中,叶甲醇提取物的抗氧化能力最强.     

银胶菊叶和花提取物对南方根结线虫的毒杀活性比较

为进一步明确银胶菊(Parthenium hysterophorus L.)的杀线虫活性,对银胶菊叶和花的不同溶剂提取物、甲醇提取物的不同萃取物以及甲醇提取物碱水层的不同极性组分对南方根结线虫(Meloidogyne incognita Chitwood)的杀虫活性进行了检测,并对不同提取物、萃取物和萃取组分进行了生物碱的定性分析.结果表明:银胶菊叶和花的蒸馏水、甲醇、乙酸乙酯和石油醚提取物的得率分别为24.5％和20.3％、19.6％和10.9％、6.8％和7.7％、2.0％和2.7％,其中,叶和花的蒸馏水和甲醇提取物的杀线虫活性均较强,而石油醚提取物的杀线虫活性最弱.用质量体积分数1.0％和0.5％的叶和花蒸馏水提取物分别处理24和48 h后试虫的校正死亡率均达到100.00％;用质量体积分数1.0％和0.5％的叶和花甲醇提取物处理48 h,试虫的校正死亡率均大于90％.叶和花甲醇提取物的碱水层、三氯甲烷Ⅰ层和Ⅱ层萃取物均具有一定的杀线虫活性,其中,用质量体积分数1.0％的花和叶碱水层萃取物以及花的三氯甲烷Ⅰ层萃取物分别处理48 h,试虫的校正死亡率均为100.00％,而三氯甲烷Ⅱ层萃取物的杀线虫活性最弱.银胶菊叶和花甲醇提取物碱水层的11个不同极性组分(A1～A11)也表现出不同程度的杀线虫活性,其中,用质量体积分数0.2％和0.1％花的A2[溶剂为V(三氯甲烷)∶V(甲醇)=10∶1]和A7[溶剂为V(三氯甲烷)∶v甲醇)=1∶1]组分以及叶的A2和A6[溶剂为V(三氯甲烷)∶V(甲醇)=2∶1]组分处理48 h后,试虫的校正死亡率均达100.00％,显著高于其他组分.定性实验结果表明:银胶菊叶和花中具有杀线虫活性的提取物、萃取物和萃取组分中均含有生物碱.研究结果说明:银胶菊花的杀线虫活性高于叶片,其毒杀活性不仅与提取部位及溶剂的种类和极性有关,还与提取物浓度及作用时间等因素有关.     

石榴果皮提取物抑菌活性研究

以12种常见的食品污染菌为供试菌,采用平板打孔法对10个品种石榴果皮的9种溶剂提取物进行抑菌效果研究,并对甲醇提取物的化学成分进行了初步分析。结果表明,甲醇提取物抑菌活性最强;石榴果皮提取物对供试菌种中的细菌的抑制效果最强,对革兰氏阳性菌的抑制效果强于对革兰氏阴性细菌的抑制效果,对酵母菌的抑制效果较弱,对霉菌几乎没有抑制作用。在供试的10个石榴品种中,‘峄城软籽’石榴果皮甲醇提取物的抑菌活性最高。化学成分系统预试结果表明,石榴果皮甲醇提取物中含有黄酮及其苷类物质、生物碱、酚类、鞣质类等成分。     

细脚拟青霉不同菌株清除DPPH自由基活性研究

在初筛基础上选择不同地理来源的10株细脚拟青霉,用二苯基苦基苯肼自由基酶标仪法比较了不同提取部位的DPPH自由基清除率。结果表明在所有供试菌株中细脚拟青霉的两个菌株清除自由基活性均较高。10株细脚拟青霉间的清除自由基活性少数相似,多数差异显著;发酵液和菌丝体提取物清除自由基活性不同;菌丝体不同溶剂先后提取所得物清除率也不同,其中氯仿提后甲醇提取物无论提取量,还是活性均较高,5分钟时的清除率最少也有66.0%(Pt02菌株),最高是Pt69菌株达到93.5%,Pt57菌株的清除率为92.8%;氯仿提取量极少,活性也不高;经氯仿和甲醇提取后的水提物,得率只有甲醇的一半左右,而活性与氯仿提取物相当,在14.11%~45.3%之间。     

根霉转化薏苡仁对其成分及抗癌活性的影响

本文以薏苡仁为材料,用一株筛选得到的根霉菌对其进行转化,转化后的薏苡仁丙酮提取物、甲醇提取物以及不同浓度乙醇的沉淀物得率明显高于未转化的薏苡仁;甲醇提取物得率增加329.60%,丙酮提取物得率增加66.7%;分离到一个转化后形成的化合物1-O-甲基-β-D-吡喃葡萄糖.MTT法活性测定表明:通过转化能增加薏苡仁丙酮提物对肿瘤细胞的细胞毒作用,并确定转化薏苡仁的活性成分仍为脂肪酸类物质;利用微生物处理中药,可以增加或改变中药的活性成分,从而达到增加或改变中药药效的目的.     

磨盘草提取物的抗氧化活性研究

目的:探究磨盘草乙醇提取物和甲醇提取物的抗氧化活性。方法:检测磨盘草乙醇提取物和甲醇提取物清除DPPH自由基能力和还原Fe~(3+)能力,评价并对比不同提取方法所得物质的抗氧化活性。结果:磨盘草乙醇提取物和甲醇提取物对DPPH自由基均具有较强的清除作用和较显著的还原Fe~(3+)能力,且随着提取液质量浓度的增加而增强。结论:磨盘草乙醇提取物和甲醇提取物均具有较强的抗氧化活性且与浓度呈现良好的量效关系。在一定质量浓度下乙醇提取物清除DPPH·能力比甲醇提取物强,甲醇提取物的还原Fe~(3+)能力比乙醇提取物强。     

窝梨果实结构及发育的研究

窝梨果实是由托杯和子房共同发育形成的假果,其横切面上,由外向内可看到表皮层,果肉,果心等几部分。表皮层,果肉由托杯发育而来,其中发布着维管束及石细胞等,果心是由子房发育而成,子房下位,５心皮组成５室,每室具２个倒生胚珠。     

Seasonal infectivity of Cacopsylla pruni, vector of European stone fruit yellows phytoplasma

Epidemiology of European stone fruit yellows was studied by focussing on the life cycle and transmission characteristics of the vector Cacopsyllapruni. The proportion of both phytoplasma positive and inoculative insects was determined for the first C. pruni adults back colonising the stone fruit trees in spring and for the new generations of the vector, hatched at the beginning of summer. We showed that in spring, as soon as the insects moved to stone fruit trees from shelter plants, they were infective. After the vector fed on infected stone fruit trees, the proportion of phytoplasma positive insects increased. The new generation colonising Prunus species also acquired the phytoplasma from their hosts although several of these insects completed the latency period on secondary hosts. Results showed that the risk of natural transmission of European stone fruit yellows-phytoplasma by C. pruni within orchards is high when the vector is present. These results have implications for the control of European stone fruit yellows.     

Analysis of Light Transport Features in Stone Fruits Using Monte Carlo Simulation

The propagation of light in stone fruit tissue was modeled using the Monte Carlo (MC) method. Peaches were used as the representative model of stone fruits. The effects of the fruit core and the skin on light transport features in the peaches were assessed. It is suggested that the skin, flesh and core should be separately considered with different parameters to accurately simulate light propagation in intact stone fruit. The detection efficiency was evaluated by the percentage of effective photons and the detection sensitivity of the flesh tissue. The fruit skin decreases the detection efficiency, especially in the region close to the incident point. The choices of the source-detector distance, detection angle and source intensity were discussed. Accurate MC simulations may result in better insight into light propagation in stone fruit and aid in achieving the optimal fruit quality inspection without extensive experimental measurements.     

Quinic acid esters of hydroxycinnamic acids in stone and pome fruit

In 21 varieties of stone and pome fruit the quinic acid esters of caffeic, p-coumaric and ferulic acids have been determined by capillary GC and HPLC. The total content of hydroxycinnamoylquinic acids was found to be between 80 and almost 900 ppm fr. wt. The results confirm that the main hydroxycinnamic acid compound in pome fruit is 5′-caffeoylquinic acid, whereas in stone fruit it is 3′-caffeoylquinic acid. Our investigations also show the regular occurrence of 3′-p-coumaroylquinic acid in stone fruit species. In sweet and sour cherries it can be the main component in concentrations of 100–200 ppm. Significant amounts of feruloylquinic acid are only found in plums and apricots. The 4′-isomers of all acids occur only in very small concentrations with the exception of 4′-p-coumaroylquinic acid in apples, the content of which exceeds that of 5′-p-coumaroylquinic acid.     

Pheromone-mediated mass trapping and population diversion as strategies for suppressing Carpophilus spp. (Coleoptera: Nitidulidae) in Australian stone fruit orchards

1 Five experiments were conducted during 1995–99 in stone fruit orchards on the Central Coast and in inland New South Wales, Australia, on the use of synthetic aggregation pheromones and a coattractant to suppress populations of the ripening fruit pests Carpophilus spp. (Coleoptera: Nitidulidae). 2 Perimeter‐based suppression traps baited with pheromone and coattractant placed at 3 m intervals around small fruit blocks, caught large numbers of Carpophilus spp. Very small populations of Carpophilus spp. occurred within blocks, and fruit damage was minimal. 3 Carpophilus spp. populations in stone fruit blocks 15–370 m from suppression traps were also small and non‐damaging, indicating a large zone of pheromone attractivity. 4 Pheromone/coattractant‐baited suppression traps appeared to divert Carpophilus spp. from nearby (130 m) ripening stone fruit. Ten metal drums containing decomposing fruit, baited with pheromone and treated with insecticide, attracted Carpophilus spp. and appeared to reduce populations and damage to ripening fruit at distances of 200–500 m. Populations and damage were significantly greater within 200 m of the drums and may have been caused by ineffective poisoning or poor quality/overcrowding of fruit resources in the drums. 5 Suppression of Carpophilus spp. populations using synthetic aggregation pheromones and a coattractant appears to be a realistic management option in stone fruit orchards. Pheromone‐mediated diversion of beetle populations from ripening fruit may be more practical than perimeter trapping, but more research is needed on the effective range of Carpophilus pheromones and the relative merits of trapping compared to attraction to insecticide‐treated areas.     

核桃果皮的发育解剖学研究

核桃果皮的发育过程可分为３个阶段,发育时期：中、内三层果皮的界线不清,维管束处于发育初期;发育中期：随着中果皮最外侧两层石细胞的出现和薄壁组织细胞体积的迅速扩大以及维管束轮数的增加,使三层果皮具较明显的界面,发育后期：中果皮的维管束递增到４－５轮,     

核果类果树DNA分子标记研究进展

介绍了DNA分子标记的种类及其在核果类果树亲缘关系上的鉴定、基因标记、定位与克隆、分子标记遗传图谱的构建以及分子标记辅助育种等上的应用进展,探讨了分子标记在核果类果树上的应用前景及尚需解决的问题。     

Comparison of Plant Pathogenic Pseudomonads from Fruit Trees

S ummary . The characteristics of 59 pathogenic pseudomonads isolated from stone fruit trees in south east England, 30 from cherry and 29 from plum, were compared with 41 isolates from pear trees in a wide range of biochemical, physiological and lesion tests. Many characteristics were common, but several consistent and stable differences were found between the stone fruit and pear groups, each of which exhibited a high level of homogeneity. The few atypical isolates in each group deviated from the majority in one or two respects only. Ten citrus and 3 lilac isolates were biochemically and physiologically indistinguishable from the pear isolates but had distinctive phage and bacteriocin sensitivities. The stone fruit isolates correspond to Pseudomonas morsprunorum and the pear isolates to Ps. syringae. The relationship between these two 'species'is discussed.