响应面法优化酶辅助提取沙苑子三萜的工艺及抗氧化活性研究

旨在研究酶法辅助技术提取沙苑子三萜的工艺及体外抗氧化活性。在单因素实验的基础上,确定液料比、酶添加量、酶解温度、酶解时间4个因素的Box-benhnken的实验设计,以三萜的提取率为响应值,采用响应面法优化沙苑子三萜的提取工艺,建立并分析各因素与指标值的数学模型;采用自由基清除能力体系评价沙苑子三萜的抗氧化活性。优化分析所得的最佳工艺参数为:液料比为40 mL/g,酶添加量为500μg/mL,酶解温度为40℃,酶解时间为50 min,三萜提取率理论值为8.08%,实际值为7.98%,其RSD为0.12%。沙苑子三萜对DPPH自由基、O_2~-·自由基、羟自由基及Fe~(3+)具有较强的清除作用。因此,该方法高效、简单,可用作沙苑子三萜的提取;沙苑子三萜具有明显的体外抗氧化活性。     

马齿苋多糖双酶法提取工艺优化及其抗氧化性研究

以马齿苋多糖得率为考察指标,通过单因素试验和正交试验优化马齿苋多糖纤维素酶和果胶酶双酶法提取工艺,并对其体外抗氧化活性进行了考察。结果表明,马齿苋多糖最佳提取工艺条件为:液料比25∶1(mL/g),纤维素酶和果胶酶的添加量分别为1.5%和2.0%,酶解温度50℃,酶解时间100 min,在该提取工艺下,马齿苋多糖得率为19.83 mg/g DW。体外DPPH·和·OH清除试验表明,马齿苋多糖对两者均有较好的清除作用,体外抗氧化活性强于VC。     

双酶法提取紫山药原花青素及其抗氧化性研究

为研究紫山药原花青素的最佳提取工艺以及抗氧化活性,以紫山药为试验材料,采用BoxBehnken中心组合试验设计和响应面分析,优化双酶法提取紫山药原花青素的提取工艺,并对其体外抗氧化活性进行评价。结果表明,最佳提取工艺为纤维素酶加酶量2.19%、果胶酶加酶量2.32%、酶解时间73 min、酶解温度45℃、液料比15 mL:1 g、pH 4.5,此条件下紫山药原花青素得率为93.06 mg/g。体外抗氧化试验结果表明,双酶法提取的紫山药原花青素具有明显的抗氧化性,对DPPH自由基(DPPH·)和羟基自由基(·OH)半数抑制率浓度IC50分别为0.165、0.267 mg/mL,清除能力强于维生素C。     

虾夷扇贝裙边糖胺聚糖的提取及其体外抗氧化活性研究

以虾夷扇贝裙边为原料,采用复合蛋白酶进行酶解,研究糖胺聚糖的最佳提取工艺条件及其体外抗氧化活性。结果表明,酶解虾夷扇贝裙边提取糖胺聚糖的最优工艺条件为提取时间3.0 h,酶添加量0.8%,提取温度50℃,料液比1:2,糖胺聚糖提取率为1.27%。体外抗氧化试验结果表明,提取的虾夷扇贝裙边糖胺聚糖具有较好的抗氧化活性,可清除·OH,O_2~-·,DPPH·,其清除能力与浓度具有显著的量效关系。     

益智总黄酮超声辅助提取工艺的响应面法优化及其抗氧化活性评价

为优化益智总黄酮超声辅助提取工艺,并评价其抗氧化活性,以益智总黄酮提取率为指标,在单因素试验考察甲醇浓度、超声时间及液料比对总黄酮提取率影响的基础上,采用响应面试验设计优化了超声辅助提取工艺,利用DPPH自由基法、ABTS自由基法和FRAP法评价了其体外抗氧化活性,并分析了益智总黄酮含量与其抗氧化活性的相关性.结果表明,益智总黄酮超声辅助提取最佳工艺为:甲醇浓度100％,超声时间20 min,液料比25:1(mL/g),该条件下益智总黄酮提取率达0.757％.益智体外具有较强的抗氧化活性,其清除DPPH自由基、ABTS自由基的IC50值分别在0.851～3.188 mg/mL(相当于生药)、0.642～1.789 mg/mL(相当于生药)之间,FRAP值在0.029～0.111 mmol/L之间,总黄酮含量与清除DPPH自由基的IC50值和总抗氧化能力FRAP值呈显著相关(P<0.05),但与清除ABTS自由基IC50值相关性不显著.     

枳椇子总黄酮提取工艺优化及其抗氧化活性研究

以枳椇子为原料,采用乙醇浸提法提取枳椇子总黄酮,并考察其抗氧化活性.通过单因素试验和正交试验优化的枳椇子总黄酮提取工艺为:乙醇体积分数40％,料液比1:50(g/mL),浸提温度40℃,浸提时间15 min,枳椇子总黄酮提取率为4.52％±0.043％.枳椇子总黄酮抗氧化性能试验结果表明:枳椇子总黄酮对羟自由基、超氧阴离子自由基、DPPH自由基和ABTS自由基均具有清除效果,具有较强的抗氧化能力,不同浓度枳椇子总黄酮的抗氧化能力差异较大,且呈现明显的剂量效应.     

菠萝皮渣多糖的酶法制备及体外抗氧化活性研究

以干菠萝皮渣为原料,采用木瓜蛋白酶法提取菠萝皮渣中的多糖,通过单因素试验和响应曲面试验,确定最优的提取工艺为木瓜蛋白酶添加量1.29%,料液比1∶16(g∶mL),酶解pH值6.37,酶解时间3.24 h,多糖提取率达到4.89%;所提多糖具有清除羟自由基的能力。     

马齿苋总黄酮的超声波辅助提取工艺优化及其抗氧化、抗肿瘤活性研究

优化马齿苋中总黄酮的甲醇浸提-超声波辅助提取最佳工艺,并评价其体外抗氧化、抗肿瘤活性。以甲醇浓度、提取温度、料液比和超声功率为因素,以总黄酮提取率为指标,通过单因素试验与正交设计优选马齿苋总黄酮的超声波辅助提取条件;测定其对DPPH?和?OH的清除能力评价抗氧化活性;MTT法测定其对人肺癌细胞A549体外增殖的影响。结果表明：马齿苋总黄酮的最佳提取工艺为：料液比1:50,温度80℃,超声功率200 W,甲醇浓度90%,提取30 min,提取2次,总黄酮提取率为6.37%。马齿苋总黄酮对DPPH?清除率在4.0 mg/mL为89.80%,对?OH清除率在20.0 mg/mL为86.07%;其质量浓度为420 μg/mL时对细胞A549增殖的抑制率为74.62%,与阳性药组无显著性差异。该优化工艺准确可靠,提取率高;马齿苋总黄酮具有较强的抗氧化和抗肿瘤活性。     

响应面法优化枸杞非酶褐变产物提取工艺及其抗氧化性研究

采用响应面法对枸杞非酶褐变反应产物提取条件进行优化,并测定其体外抗氧化活性。结果表明,枸杞非酶褐变反应产物最佳提取条件为:乙醇浓度31%,料液比1∶20(g/m L),提取温度46℃,提取时间1.4 h,此条件下非酶褐变反应产物提取率为46.40%。按照最优提取工艺分离得到的组分LB-Ⅰ和LB-Ⅱ,抗氧化性测定结果表明,LB-Ⅰ和LB-Ⅱ对羟自由基和DPPH自由基均有一定的清除能力,随着提取物浓度的升高,其抗氧化能力增强,其中组分LB-Ⅰ的抗氧化能力优于LB-Ⅱ。     

龙眼果皮酶促褐变产物的提取、稳定性及抗氧化活性研究

为了研究龙眼果皮酶促褐变产物的最佳提取工艺、稳定性和抗氧化活性,以样品中总蒽醌含量为指标,通过单因素和正交试验法,考察乙醇的浓度、料液比、提取时间、提取温度4个因素对应用回流法提取褐变产物的影响,探讨提取龙眼果皮中酶促褐变产物的最佳工艺条件。采用分光光度法对褐变产物的稳定性和体外抗氧化活性进行了测定。结果表明,回流法提取酶促褐变产物最佳工艺条件为：乙醇浓度为70%,提取时间为8 h,料液比为1:2,提取温度为40℃。在试验温度范围内,酶促褐变产物比较稳定;但对光照比较敏感,尤其是在紫外光下稳定性较差;在酸性条件下的稳定性比在碱性和中性条件下好;在4种不同种类添加剂影响下,其稳定性均变差。体外抗氧化试验结果表明,龙眼果皮总蒽醌浓度为9.55 μg/mL时,对1,1-二苯基-2-三硝基苯肼自由基(DPPH?)清除率为74.1%;浓度为4.55 μg/mL时,羟基自由基(?OH)清除率达81.6%;浓度为6.70 μg/mL时,超氧阴离子自由基(?O2-)清除率达86.1%。回流法可提取龙眼果皮中酶促褐变产物。温度对酶促褐变产物稳定性影响不明显,光照、pH、食品添加剂因素影响其稳定性。酶促褐变产物具有一定的清除DPPH?、?OH和?O2-自由基的能力。     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.