共查询到20条相似文献，搜索用时 62 毫秒
1.
为获得葡萄多糖提取的最佳条件,本研究以新鲜户太8号葡萄为材料,采用水提醇沉法对不同的提取温度、液料比、乙醇体积进行单因素实验,并在此基础上采用三因素三水平正交试验对提取条件进行优化。结果表明,温度为80℃,液料比为1:2,浓缩液的6倍体积的95%乙醇进行沉淀可得到较好的提取效果。 相似文献
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响应面法优化超声提取锁阳多糖工艺研究 总被引：1，自引：0，他引：1
为探讨在超声波作用下锁阳多糖提取的工艺条件,以锁阳为原料,在单因素试验基础上,采用响应面法研究了超声提取时间、液料比和提取温度对锁阳多糖提取率的影响。结果表明:提取时间和液料比对多糖提取率均有显著影响,提取温度影响不显著;优化出锁阳多糖超声提取工艺条件为提取温度97.62℃,液料比7.75∶1、提取时间85.57 min,在此条件下锁阳多糖的理论提取率为23.1%。与传统水浸法提取相比,超声提取锁阳多糖具有明显的优势,提取时间较短,液料比和温度较低,以及较高的提取率等。 相似文献
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《中国南方果树》2020,(4)
为了更好地开发和利用神秘果资源,优化神秘果叶粗多糖的提取工艺,并评价其抗氧化能力。本研究采用单因素试验了液料比、提取温度、提取时间和提取次数;在单因素试验基础上,建立三因素三水平的正交试验设计,对提取工艺进行优化,并测定神秘果叶粗多糖的总抗氧化能力(FRAP)。结果表明,提取神秘果叶粗多糖的最佳工艺条件为液料比20∶1(V/m)、提取温度85℃、提取时间60 min,提取3次,在此条件下,神秘果叶粗多糖提取率为(4.93±0.22)%;3个因素对神秘果叶粗多糖提取率影响从大到小依次为提取温度提取时间液料比。同时发现神秘果叶粗多糖具有一定的抗氧化活性。 相似文献
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《中国蔬菜》2021,(5)
采用超声波辅助纤维素酶法对绣球菌多糖提取进行试验设计优化,以确定最佳提取条件。对超声功率、超声时间、提取温度、料液比、纤维素酶添加量等5个因素进行单因素试验,确定在超声功率570 W、纤维素酶添加量3%的条件下,选定料液比、超声时间、提取温度作为3个交互因素,进行Box-Behnken试验设计和响应面优化。预测最佳方案为料液比1∶87.62(g · mL~(-1)),提取温度38.4 ℃,超声时间94.56 min,预测多糖得率为31.49%。对最佳预测模型参数进行验证,结果表明,在料液比1∶90(g · mL~(-1)),超声温度38 ℃,提取时间95 min的条件下,对5 g绣球菌粉进行粗多糖提取,提取率达到30.60%;对50 g绣球菌粉进行粗多糖提取,第1次粗多糖提取率为31.70%,第2次粗多糖提取率为7.1%。将提取的粗多糖进行浓缩、除蛋白、除色素及透析纯化后,多糖保留率为73.20%。 相似文献
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水提法同步提取分离香菇中蛋白质和多糖的工艺研究 总被引：1，自引：0，他引：1
《食药用菌》2019,(5)
通过水提法同步提取分离香菇中的蛋白质和多糖,采用单因素实验研究料液比、提取温度、提取时间与蛋白质和多糖提取率的关系,并通过正交实验优化工艺条件。结果为,影响蛋白质提取率的主次因素为提取温度料液比提取时间;影响多糖提取率的主次因素为料液比提取温度提取时间。综合分析得到提取的最佳工艺组合为料液比20、提取温度100℃、提取时间3.5 h(二次提取)。该组合下蛋白质提取率为6.90%,多糖提取率达38.50%。 相似文献
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以红蜡蘑为试材,研究了液料比、超声功率、超声时间、超声温度、提取次数对多糖得率的影响,在单因素试验基础上,采用正交实验优化了工艺条件,对提取产物多糖进行了DPPH·、ABTS+·清除研究。结果表明:对多糖提取率影响最大的是提取次数,其次是液料比,提取时间影响最小;最佳提取工艺条件为提取3次,液料比20∶1mL·g~(-1),超声功率300 W,超声温度70℃,超声时间40 min,在此条件下多糖提取率达6.27%。多糖对DPPH·、ABTS+·有一定的清除作用,说明红蜡蘑多糖具有一定的抗氧化活性。 相似文献
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研究了提取温度、提取时间、料液比、pH和提取次数对金针菇水溶性粗多糖提取率的影响。单因素试验结果表明,pH和提取次数的影响作用较弱,二因素的适宜水平分别为7和1次;而提取温度、提取时间和料液比的影响较显著。采用Box—Behnken组合设计进一步考察3个因子对金针菇粗多糖提取率的影响。试验结果表明,对金针菇粗多糖提取率影响大小依次为：料液比〉提取时间〉提取温度;所确定的最优提取条件为：提取温度87℃,提取时间2h,料液比1：20,在此条件下金针菇粗多糖提取率为1．38％。 相似文献
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AIM: Although endovascular radiotherapy inhibits neointimal hyperplasia, the exact alterations induced by β-particles irradiation remain to be elucidated. The objective of this study was to investigate the ability and the cellular mechanism of local β-particles emission from 188Re to inhibit vascular smooth muscle cells (SMCs). METHODS: The SMCs in vitro were irradiated by 188Re with single doses of 2.6 Gy-25.8 Gy. The effects of β-particles on SMCs, such as effective irradiate doses, the period of inhibition for SMCs proliferation, the changes of cell proliferation rate and DNA synthesis rate, cell cycle progression and related gene expression, were investigated by cell count, [3H]-TdR incorporation, cell cycle progression analysis, cell viability and immunocytochemistry, respectivecy. RESULTS: β-particles irradiation with dose of 5.2 Gy could inhibit significantly SMCs proliferation. At dose of 20.6 Gy DNA synthesis inhibitory rate was 92%, SMCs proliferation rate was only 3%. Renoval of 188Re did not abolish the inhibitory effects of β-particles on SMCs proliferation. The expression of P53 was up regulation and PCNA was down regulation after irradiation. CONCLUSION: β-particles from 188 Re was significantly effective and permanent in inhibiting SMCs proliferation, and inhibitory effect was in dose-dependet manner ED50was 5 Gy, the best dose to inhibit SMCs proliferation was 20 Gy. β-particles irradiation induced SMCs to occur G0/G1 arrest, damaged the ability of SMCs reproliferation and led to cell clonogenic death. P53 and PCNA had regulatiory effects on SMCs proliferation after β-particles irradiation. 相似文献
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AIM:To study the effect of L-Arg on plasma content of endothelin (ET) and the expression of proto-oncogene c-fos mRNA in the left ventricle of rats with renovascular hypertensive hypertrophy. METHODS: The level of c-fos mRNA were measured by in situ hybridization. The ET in plasma were measured by radioimmunoassay. RESULTS:After eight weeks of treatment with L-Arg, the expression of c-fos decreased markedly (P＜0.01). The ET content in plasma also decreased significantly by L-Arg(P＜0.01).CONCLUSION: Plasma ET content and the expression of c-fos in the left ventricle of rats with renovascular hypertensive hypertrophy could be decreased by L-Arg administration. 相似文献
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《International Journal of Fruit Science》2013,13(3):101-120
Abstract Saskatoon berry (Amelanchier alnifolia Nutt., Rosaceae) and blueberry (Vaccinium corymbosum L., Ericaceae) are substantially equivalent in all characteristics that are important to the consumer, including fruit color, shape, size, nutrition, texture, and uses. In addition, both fruits are native to North America and they have practically identical historical uses and known health benefits. Their composition, processing, nutritional value and metabolism, intended uses, and levels of undesirable substances are compared. 相似文献
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多效唑对猕猴桃离体试管苗生长及内源激素的影响 总被引：18，自引：0，他引：18
多效唑（ＰＰ３３３）处理猕猴桃试管苗，降低了其生长强度；植株体内的ＧＡ３、ＩＡＡ和ＺＴ含量下降，ＡＢＡ的含量上升，乙烯释放率增加；并且能降低外源的ＧＡ３和ＩＡＡ促进生长的作用，而外源的ＧＡ３和ＩＡＡ又能不同程度地逆转多效唑的抑制作用，使植株恢复生长。 相似文献
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HU Zhi-cheng ZHU Jia-yuan ZHU Bin GUO Dong CHEN Bin ZHANG Kai HU Kun-hua LI Ming-tao TANG Bing 《园艺学报》2011,27(9):1802-1806
AIM: To investigate and screen the sensitive proteins in the formation mechanism of pathological scars by comparing the results of differential proteomic analysis between pathological scars and normal skin.METHODS: Two-dimensional gel electrophoresis was used to detect the protein expression profiles in 8 keloid patients, 8 hypertrophic scar patients and 3 matched normal skin patients.The proteins that showed differential expression of over 4-fold change were cut and analyzed by MALDI-TOF/TOF mass spectrometry.RESULTS: A two-dimensional protein profiling comparison between pathological scars and normal skin was successfully established.On average, 2 978 spots in keloid, 2 975 spots in hypertrophic scar and 3 053 spots in normal skin were identified using gel analysis software.Compared with normal skin, there were totally 36 differentially-expressed proteins in keloid and hypertrophic scar identified from the spots of over 4-fold change, including 16 proteins in both keloid and hypertrophic scar (8 up-regulated and 8 down-regulated), 11 only in keloid (9 up-regulated and 2 down-regulated) and 9 only in hypertrophic scar (4 up-regulated and 5 down-regulated).CONCLUSION: Proteomic analysis can identify the proteins with variance of pathological scars versus normal skin, thus providing probable new clues to reveal the formation mechanism of pathological scars. 相似文献
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The objective of this study was to establish a cryopreservation protocol for hawthorn shoot apices (Crataegus pinnatifida Bge.). Cryopreservation was carried out via encapsulation–dehydration, vitrification, and encapsulation–vitrification on shoot apices excised from in vitro cultures. We began by showing that cold-acclimation enhanced the regrowth of cryopreserved apices from 10.0 to 65.5% in encapsulation–dehydration. We then decided that the encapsulation–dehydration method was an optimal cryopreservation method for hawthorn shoot apices in terms of its high recovery after cryopreservation as well as its ease of use compared with vitrification and encapsulation–vitrification. In encapsulation–dehydration, the protocol leading to optimal regrowth was as follows: after cold-acclimation at 5 °C in the dark for 2 weeks, excised shoot tips were pretreated for 24 h at 25 °C on hormone-free Murashige and Skoog [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue culture. Physiol. Plant. 15, 473–497] (MS) basal medium with 0.4 mol/L sucrose, then encapsulated and precultured in liquid MS medium with 0.8 mol/L sucrose for 16 h at 25 °C. Precultured beads were dehydrated for 6 h at 25 °C in the dessicator containing 50 g silica gel to a moisture content of 15.3% (fresh-weight basis) before cryostorage for 1 h. In addition, we examined the effect of adding glycerol to both the alginate beads and loading solution to enhance regrowth after cryopreservation in encapsulation–dehydration. In the present study, it was shown that adding 0.5 mol/L glycerol resulted in high regrowth percentages (82.5–90.0%) in four Crataegus species. 相似文献
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AIM:To investigate the effect of metallothionein(MT) on proliferation of rat vascular smooth muscle cells (VSMCs) stimulated by homocysteine and its mechanism. METHODS:VSMCs proliferation was measured by [3-H]-TdR incorporation, mitogen-activated protein kinase(MAPK)activity were determined by immunoprecipitation method, the intracellular contents of MT and malondialdehyde (MDA)were assayed by -hemoglobin saturation method and TBA reaction, respectively, and lactate dehydrogenase (LDH) leakage was measured by NADH oxidation. RESULTS:Hcy(10-6-10-4 mmol/L) stimulated [3-H]-TdR incorporation by the VSMCs in a concentration-dependent manner. Compared with control, [3-H]-TdR incorporation in VSMCs treated with 0.1 mmol/L Hcy was increased by 4.2 fold (P＜0.01). Meanwhile, Hcy enhanced MAPK activity, MDA formation and LDH release (P＜0.01)in a concentration-dependent manner. Treatment of VSMCs with MT alone did not change above parameters, compared with control. However, MT (10-6-10-4 mol/L)attenuated significantly Hcy-stimulated proliferation of VSMCs (P＜0.01)in a concentration-dependent manner. And MT inhibited obviously Hcy-induced activation of MAPK activity, MDA formation and LDH release. Preincubation of VSMCs with 0.5 mmol/L ZnCl2 for 6 h induced an increase cellular MT content by 5.7-fold (P＜0.01). The MT-overexpressed VSMCs resisted Hcy-stimulating action on MAPK activity, MDA formation and LDH leakage (P＜0.01). CONCLUSION:These results show that MT has an inhibitory effect on Hcy-induced VSMCs proliferation, and that MT could inhibit Hcy-stimulated MAPK activity and lipid peroxidation. 相似文献
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Duncan Brean W. Boyle Shannon Breininger David R. Schmalzer Paul A. 《Landscape Ecology》1999,14(3):291-309
Historic landcover dynamics in a scrubby flatwoods (Tel-4) and scrub landscape (Happy Creek) on John F. Kennedy Space Center were measured using aerial images from 1943, 1951, 1958, 1969, 1979, and 1989. Landcover categories were mapped, digitized, geometrically registered, and overlaid in ARC/INFO. Both study sites have been influenced by various land use histories, including periods of range management, fire suppression, and fire management. Several analyses were performed to help understand the effects of past land management on the amount and spatial distribution of landcover within the study sites. A chi-squared analysis showed a significant difference between the frequency of landcover occurrence and management period. Markov chain models were used to project observed changes over a 100-year period; these showed current management practices being effective at Tel-4 (restoring historic landscape structure) and much less effective at Happy Creek. Documenting impacts of past management regimes on landcover has provided important insight into current landscape composition and will provide the basis for improving land management on Kennedy Space Center and elsewhere. 相似文献
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AIM: Previous studies performed with XBP-01 in vitro indicated that XBP-01 could inhibit vascular smooth muscle cells from being transformed into foam cell and could eliminate the atherosclerotic plaque in C57BL/6J mouse. This experiment is to investigate its mechanism of eliminating plaques in vitro. METHODS: The cultured porcine artery smooth muscle cells incubated with XBP-01 of 0.1 mg/L for 24 h after preincubated with oxidized low density lipoprotein of 15 mg/L for 72 h in vitro. The samples were analyzed by fluorescence microscope, confocal microscope system and flow cytometry. RESULTS: Apoptosis was triggered by being incubated with oxidized low density lipoprotein and this process was accelerated additionally by being incubated with XBP-01. CONCLUSION: XBP-01 can be effective in eliminating atherosclerotic plaque by accelerating the process in which oxidized low density lipoprotein induced smooth muscle cell apoptosis. 相似文献
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Species distribution models (SDMs) often use elevation as a surrogate for temperature or utilise elevation sensitive interpolations
from weather stations. These methods may be unsuitable at the landscape scale, especially where there are sparse weather stations,
dramatic variations in exposure or low elevational ranges. The goal of this study was to determine whether radiation, moisture
or a novel estimate of exposure could improve temperature estimates and SDMs for vegetation on the Illawarra Escarpment, near
Sydney, Australia. Forty temperature sensors were placed on the soil surface of an approximately 12,000 ha study site between
November 2004 and August 2006. Linear regression was used to determine the relationship with environmental factors. Elevation
was correlated more with moderate temperatures (winter maximums, summer minimums, spring and autumn averages) than extreme
temperatures (summer maximums, winter minimums). The correlation (r
2) between temperature and environmental factors was improved by up to 0.38 by incorporating exposure, moisture and radiation
in the regressions. Summer maximums and winter minimums were predominately determined by exposure to the NW and coastal influences
respectively, while exposure to the NE and SW was important during other seasons. These directions correspond with the winds
that are most influential in the study area. The improved temperature estimates were used in Generalised Additive Models for
37 plant species. The deviance explained by most models was increased relative to elevation, especially for moist rainforest
species. It was concluded that improving the accuracy of seasonal temperature estimates could improve our ability to explain
the patchy distribution of many species.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献