类球红细菌类胡萝卜素抗氧化活性研究

研究了研磨法、超声波法、酸溶辅助超声波法和菌体浓度对类球红细菌类胡萝卜素抗氧化活性的影响。结果表明,不同提取方法和固液比条件下,类球红细菌类胡萝卜素均具有清除DPPH自由基能力、抗脂质过氧化能力和还原能力。酸溶辅助超声波法提取的类胡萝卜素产率最高、抗氧化活性最好。类球红细菌类胡萝卜素具有一定的抗氧化活性,其抗氧化活性随菌体浓度的增加而增加。     

酶法辅助超声波法提取类球红细菌辅酶Q10条件优化

采用单因素和正交实验优化了酶法辅助超声波法提取类球红细菌辅酶Q10的提取条件。结果表明,较优的辅酶Q10提取条件:超声波总时间14 min,超声波振幅30%,超声波工作/间歇时间1 min/1 min,料液比115,溶菌酶添加量300μL,酶解pH 7.2,酶解温度37℃,酶解时间90 min。优化后辅酶Q10的提取率比优化前提高了91.9%。     

类球红细菌发酵生产类胡萝卜素条件优化

本文对类球红细菌3757产类胡萝卜素进行了发酵条件优化,结果得到了较优的培养基组成:葡萄糖2%,苹果酸钠0.5%,酵母浸粉1.3%,硫酸铵0.9%,磷酸氢二钾0.09%,磷酸二氢钾0.06%,生长因子溶液1%,p H 8.0;其中,生长因子溶液配方:维生素B1 0.1%,烟酰胺(VPP)0.1%,生物素0.0016%。较优培养条件为:接种量5%,转速200 r/min,种龄24 h,发酵温度32℃,发酵时间40 h。优化后类胡萝卜素产率较优化前提高了76.2%。     

香蕉皮类胡萝卜素提取工艺条件的研究

为探究香蕉皮类胡萝卜素提取及综合利用的可能性,采用单因素试验与正交试验相结合的方法优化香蕉皮类胡萝卜素的提取工艺条件。结果表明：其最佳提取工艺条件为：以丙酮为提取溶剂、料液比1∶25、提取温度45℃、提取时间75min,在此工艺条件下可获得最佳提取效果,类胡萝卜素提取量平均值为12.541 mg/g。另用超声波辅助提取法,得到香蕉皮中类胡萝卜素提取量平均值为13.740mg/g,在提取时间仅为20min的情况下,比普通浸提法的提取量增加了9.56%,提取效率大大提高。     

辣蓼总黄酮超声波辅助提取条件优化研究

目的:优化超声波辅助法提取辣蓼黄酮类化合物的工艺条件。方法:实验从超声温度、料液比、乙醇浓度和超声时间四个方面对黄酮类化合物的提取效果进行了探讨,通过单因素试验确定提取黄酮类化合物的较优水平,再结合正交试验确定辣蓼全草中黄酮类化合物的最优提取工艺。结果和结论:经研究所得工艺的最佳参数为:乙醇浓度60%,料液比1∶45,超声温度50℃,提取时间50 min。在此工艺条件下得到黄酮类化合物含量为55.8mg/g。由此证明辣蓼中黄酮类化合物能够利用超声波辅助法来方便有效地提取。     

正交实验优选沟眶象甲壳素的超声波提取工艺

以沟眶象干粉为原材料,通过单因素实验和正交实验优化了沟眶象甲壳素的超声波辅助酸碱法提取工艺。在不同条件下,研究超声处理的时间、功率、温度以及柠檬酸、氢氧化钠的浓度和固液比对甲壳素提取的影响,确定了沟眶象甲壳素的最佳提取工艺条件:氢氧化钠质量分数9%、固液比1︰16、温度65℃、时间50 min、超声功率60%;柠檬酸质量浓度1.8 g/L、时间25 min、固液比1︰12、室温、超声功率100%。在此工艺条件下得到的甲壳素样品得率为16.50%,比传统酸碱法提取甲壳素的得率减少2.69%,但优化后的超声波辅助酸碱法所用时间仅占传统酸碱法的4.31%,因此超声波辅助酸碱法具有明显的优势。     

类球红细菌SOD发酵条件优化

本文对类球红细菌3757产SOD进行了发酵条件优化,结果得到了较优的培养基组成(g/L):苹果酸3,胰蛋白胨4,磷酸氢二钾0.9,磷酸二氢钾O.6,硫酸镁0.2,无水氯化钙0.075,硫酸亚铁0.012,EDATA 0.02,微量元素溶液10 mL,生长因子溶液10 mL,pH 7.5。其中,微量元素溶液配方(g/L):硼酸2.8,硫酸锰1.6,钼酸钠0.76,硫酸锌0.24,硫酸铜0.04;生长因子溶液配方(g/L):维生素B_1 1,烟酰胺(VPP)1,生物素0.016,对氨基苯甲酸1。较优培养条件为:接种量5%,转速150 r/min,种龄24 h,发酵温度32℃,发酵时间24 h。优化后酶活力较优化前提高了88.0%。     

红酵母产类胡萝卜素提取工艺的优化研究

目的:从提取溶剂及提取条件等方面对红酵母产类胡萝卜素提取工艺进行了优化研究。方法:用单因子实验对提取溶剂进行了筛选;用析因试验对提取条件进行了分析研究;通过最陡爬坡实验和中心组合设计实验,优化得到了最佳的类胡萝卜素提取条件。结果:结果表明丙酮和二甲亚砜组成的复合体系是理想的提取溶剂。溶剂添加量、提取温度、提取时间、丙酮与二甲亚砜组分比例都对红酵母产类胡萝卜素提取产生一定影响,其中溶剂添加量和丙酮与二甲亚砜组成比例的影响最为显著(P<0.001)。最佳优化提取条件为:溶剂添加量为42.66%(V/V),丙酮与二甲亚砜组成比例为62.47%(V/V),温度为20℃,提取时间为90min,在此条件下红酵母产类胡萝卜素的最大提取量为5.51μg/ml。结论:实验得到了红酵母发酵产类胡萝卜素溶剂提取条件的一个非常合适的模型。     

优美红游动菌类胡萝卜素的提取条件研究

研究了优美红游动菌(Rhodoplanes elegans)的生长以及类胡萝卜素的产生,通过比较4种广泛采用的细胞破碎方法,对优美红游动菌(Rhodoplanes elegans)类胡萝卜素的提取条件进行了研究,结果表明:类胡萝卜素的产生与菌种的生长曲线相符合,菌种活化后培养45h,类胡萝卜素的含量趋于稳定;取此时培养液,采用超声波法破碎细胞(破碎功率640W,时间10min),类胡萝卜素提取效果最好,初提液类胡萝卜素的提取率约为7.62mg·(g干菌体)^-1;酸热法对色素的破坏严重。这为进一步开发利用天然色素资源提供了一定的理论依据。     

超声波辅助薯蓣总皂苷苷键裂解工艺研究

研究了超声波辅助穿山龙薯蓣总皂苷苷键裂解的工艺条件。以薯蓣总皂苷的降解率和皂苷元的收率为考察指标,探讨了超声波影响薯蓣总皂苷苷键裂解的因素,并与常规的酸解法进行比较。得出超声波辅助薯蓣总皂苷苷键裂解的单因素优化条件:当薯蓣总皂苷的浓度固定时(1×10-2g/mL),乙醇溶液作为溶剂优于水,其最佳浓度为75%,用功率为800W超声波处理总皂苷的乙醇溶液120min效果较好。实验结果表明,与常规的酸解法相比,超声波辅助降解法具有时间短、能耗低、无污染等优点。     

A method of extraction of DNA from birch

A method of DNA extraction is given which is suitable for use with birch (Betula spp.) material collected from natural populations. Such material is frequently old and insect-damaged, and contains high levels of polyphenols. The method relies on repeated extraction of the material with a high molarity urea phosphate buffer, and yields DNA suitable for RFLP analysis.     

Two-phase extraction culture of Botryococcus braunii producing long-chain unsaturated hydrocarbons

Hydrocarbon recovery was 32% and the total production of hydrocarbon in a two-phase extraction culture of Botryococcus braunii was 675 mg l^–1, which was 19% higher than that of single-phase culture. Addition of 60 ml dihexyl ether at mid-growth phase gave the highest yield. Specific growth rate and recovery of hydrocarbon in this case were 0.022 h^–1 and 26%, respectively.     

A reliable method for extraction of RNA from various conifer tissues

Summary A simple and efficient procedure suitable for extraction of high-quality RNA from cultured conifer tissues, somatic embryos, zygotic embryos, needles, stem and root tissues was developed. It produced from 100 g up to 700 g total RNA per gram tissue dependent on the types of tissues used. RNA quality was estimated by spectrophotometry, agarose gel electrophoresis, in vitro translation of mRNA, cDNA synthesis and Northern blot analysis. The method also worked well with Arabidopsis thaliana and tobacco tissues.Abbreviations CTAB cetyltrimethylammonium bromide - DEPC diethylpyrocarbonate - PVP polyvinylpyrrolidone - SDS-PAGE sodium dodecyl sulphate-polyacrylamide gel electrophoresis     

A method for extraction of total RNA fromPinus radiata and other conifers

Carbohydrates, polyphenolic compounds, terpenoids and tannins interfere with the extraction of intact, uncontaminated total RNA from conifers. A method for extraction of total RNA fromPinus radiata is described. This method uses cesium trifluoroacetate in the ultracentrifugal separation of RNA to overcome the problems of co-purification of contaminating secondary metabolites.     

Elimination of oxalate contamination in RNA isolation from<Emphasis Type="Italic">Rumex obtusifolius</Emphasis>

Many plant RNA isolation techniques aim to prevent contamination by means of secondary phenolics, carbohydrates, RNase, and other chemicals. However, when applied in our laboratory to the isolation of RNA fromRumex obtusifolius, these protocols failed to produce good quality RNA. A major problem was contamination of the RNA samples with the secondary metabolite oxalate. The relative quantities of guanidine isothiocyanate extraction buffer to plant tissue used in the protocol had significant effects on oxalate contamination. An increase in extraction buffer, from 1.5 mL in the original method to 15 mL per 200–300 mg of tissue in our protocol, removed the oxalate from the RNA. This RNA was of a good quality and was suitable for molecular biology applications.     

Use of a 'Miniprep' for rapid extraction of plasmids from vancomycin- and gentamicin-resistant Enterococcus faecium

Conventional methods of plasmid extraction are largely unsuited to diagnostic laboratories. The 'Miniprep' is a rapid method that utilises a centrifugable column to separate plasmid DNA from chromosomal DNA. We have modified this technique to extract plasmid DNA from seven strains of vancomycin- and gentamicin-resistant Enterococcus faecium (VGREF): 1% mannitol was added to the growth medium and cell lysis was achieved by incubation in 10 mg of lysozyme/ml in 10 mM Tris, 1 mM EDTA and 25% sucrose at pH 8.0. RNase A was added to plasmid eluate rather than at the lytic step. In comparison to a standard phenol/chloroform method, Miniprep completely eliminated chromosomal interference in gel electrophoresis but otherwise produced identical plasmid profiles. Plasmids obtained from the VGREF ranged from 42 to 1.3 Md. Band densities on a single elution from the Miniprep varied from 8.3 to 106.3 relative units. Double elution increased band densities from the same preparation from 30.4 to 196 relative units; mean percentage increases per track between 7.0 and 34.6%. This method is suitable to achieve plasmid DNA extraction from VGREF within 1 h, making the process more suitable for diagnostic laboratories.     

A rapid and high yielding DNA miniprep for cotton (Gossypium spp.)

A rapid DNA minipreparation method was developed for cotton and yields 500–600 μg DNA from 1.0 g fresh leaf tissue. Cotton DNA extracted using this method is completely digested with restriction enzymes, supports PCR and Southern DNA analyses and was used successfully in these applications. An erratum to this article is available at .     

Comparative studies of four protein preparation methods for proteomic study of the dinoflagellate Alexandrium sp. using two-dimensional electrophoresis

Alexandrium is a wide-spread genus of dinoflagellate causing harmful algal blooms and paralytic shellfish poisoning around the world. Proteomics has been introduced to the study of Alexandrium, but the protein preparation method is still unsatisfactory with respect to protein spot number, separation and resolution, and this has limited the application of a proteomic approach to the study of dinoflagellates. In this study we compared four protein preparation methods for the two-dimensional electrophoresis (2DE) analysis of A. tamarense: (1) urea/Triton X-100 buffer extraction with trichloroacetic acid (TCA)/acetone precipitation; (2) direct precipitation with TCA/acetone; (3) 40 mM Tris (hydroxymethyl) aminomethane (Tris) buffer extraction; and (4) 50 mM Tris/5% glycerol buffer extraction. The results showed that, among the four protein preparation methods, the method combining the urea/Triton X-100 buffer extraction and TCA/acetone precipitation allowed detection of the highest number and quality of protein spots with a clear background. Although the direct TCA/acetone precipitation method also detected a high number of protein spots with a clear background, the spot number, separation and intensity were not as good as those obtained from the urea/Triton X-100 buffer extraction with TCA/acetone precipitation method. The 40 mM Tris buffer and 50 mM Tris/5% glycerol buffer methods allowed the detection of fewer protein spots and a pH range only from 4 to 7. Subsequently, the urea/Triton X-100 buffer extraction with TCA/acetone precipitation method was successfully applied to profiling protein expression in A. catenella under light stress conditions and the differential expression proteins were identified using MALDI TOF–TOF mass spectrometry. The method developed here appears to be promising for further proteomic studies of this organism and related species.     

Electroinduced release of invertase from Saccharomyces cerevisiae

Invertase liberation from Saccharomyces cerevisiae was detected after application of series of rectangular millisecond electric pulses. Maximal yield (60% from the activity in crude extract) was achieved within 8 h after pulsation. As shown by staining SDS-PAGE for invertase activity, the main part of liberated enzyme is a high molecular weight periplasmic invertase.     

Microwave-assisted extraction of embelin from <Emphasis Type="Italic">Embelia ribes</Emphasis>

A rapid and efficient microwave-assisted extraction (MAE) process for the selective extraction of embelin from Embelia ribes was developed. Solvent selection, microwave energy input and solid loading were optimized. The rate of extraction and purity of embelin depended upon the solvent used and exposure time to microwaves. Maximum MAE was achieved in acetone with total yield of 92% (w/w) embelin with 90% (w/w) purity with 1% (w/v) raw material loading at 150 W power level in 80 s. Non-polar solvents, such as hexane and dichloromethane, were not effective for the selective extraction of embelin.