从黑曲霉提取甲壳素和壳聚糖

采用电解法从培养的黑曲霉湿菌体制甲壳素 ;采用碱提取法从培养的黑曲霉湿菌体制壳聚糖。甲壳素提取的得率干菌重量的 2 0 6 %。所得干燥壳聚糖产品的游离胺基为 93 76 % ,0 5%壳聚糖的 0 5%醋酸的运动粘度为 5 4 4 8× 10 6 m2 /s ,粘均分子量为 8 2 75× 10 4 ,含水量为 9 16 % ,产品得率为 12 11%。     

枸杞色素及多糖的不同提取次序对其得率及抗氧化活性的影响

为探究先后提取枸杞多糖及枸杞色素时对各自得率的影响。本研究通过分别考察这两种成分在提取过程中的提取溶剂、提取温度、料液比、提取次数及提取时间等因素对枸杞色素和枸杞多糖的得率影响,确定枸杞色素和枸杞多糖在提取次序不同时,两者的最佳提取工艺以及对DPPH·和·OH自由基清除率。结果表明,首先提取枸杞多糖后,枸杞色素的最佳提取工艺为采用正己烷,80℃时,料液比1∶10,提取2次,每次1 h,枸杞色素得率为2.48%,此时枸杞多糖得率为7.45%;而首先提取枸杞色素后,采用了超声辅助提取的方式提取枸杞多糖,发现超声效率为25%,料液比1∶10,提取20 min,枸杞多糖得率为5.23%,此时枸杞色素得率为3.93%。因此,首先提取枸杞多糖,使其平均得率为7.45%,而后提取枸杞色素,其平均得率为2.48%;总体上,枸杞色素1和枸杞多糖1对DPPH·自由基清除率都较高,枸杞多糖1对·OH自由基清除率较高,其抗氧化活性都接近Vc。     

杜仲药用有效成分提取方法研究

为优选杜仲的提取工艺条件 ,本实验以杜仲提取液中氯原酸的含量和浸膏得率为指标 ,采用四因素三水平正交设计法 ,筛选影响杜仲提取工艺的因素 ,探索最优的提取工艺条件。实验证明合理的提取方法为 :12倍 6 0 %的乙醇回流 3次 ,每次 2小时 ;所得杜仲提取物中氯原酸含量为 8 72mg/g生药 ,浸膏得率为 2 0 6 8%。     

辣木叶总黄酮响应面法微波萃取工艺优化及其体外降糖效果观察

利用响应面法优化微波萃取辣木叶总黄酮工艺。选取乙醇浓度、微波功率、提取时间、液料比为影响因素,总黄酮得率为评价指标。在单因素实验的基础上,通过4因素3水平Box-Behnken中心组合试验建立黄酮得率的二次多项式回归方程,研究以上因素对总黄酮得率的影响。结果表明最佳提取工艺条件为:乙醇浓度58%,微波功率397 W,提取时间8 min,液料比59∶1,该条件下,总黄酮得率为3.45%,与预期基本相符。采用Hep G2细胞研究辣木叶总黄酮体外降糖效果,检测该细胞24 h的葡萄糖摄取量。结果表明:在高糖环境下,辣木叶总黄酮能促进Hep G2细胞对葡萄糖的消耗;相同质量浓度下,经微波萃取的总黄酮降糖活性较回流提取得到的强。     

青橄榄浸膏的提取及其抗氧化活性研究

为优化青橄榄浸膏提取工艺,并探讨其抗氧化性。以茂名盛产的青橄榄为原料,采用超声波辅助乙醇提取法,以总黄酮和总多酚得率为评价指标,考察各因素对青橄榄浸膏提取效果的影响。采用邻苯三酚自氧化法、结晶紫法和DPPH清除能力评价青橄榄浸膏的抗氧化活性。结果显示,浸膏的最佳提取工艺为:乙醇体积分数70%,料液比1∶18 (g∶mL),超声提取温度50℃,时间6 min(超声提取阶段);单纯有机溶剂提取温度60℃,时间45 min(有机溶剂浸提阶段);此条件下总黄酮得率为1. 76%,总多酚得率为15. 53%。终产物浸膏在0. 3 mg/mL浓度下对超氧阴离子自由基抑制率为22. 74%,相当于同等质量浓度的抗坏血酸抑制效果的23. 47%;在0. 02 mg/mL浓度下对羟基自由基的清除率为67. 32%,相当于同等质量浓度的抗坏血酸清除效果的112. 58%;在0. 2 mmol/mL的DPPH溶液体系中,0. 15 mg/mL的浸膏对DPPH的清除率为95. 40%,相当于同等质量浓度的抗坏血酸清除效果的140. 83%;总体来讲,浸膏具有良好的抗氧化能力,虽然对超氧阴离子自由基抑制率弱于抗坏血酸,但羟基自由基的清除率及DPPH清除率均优于抗坏血酸。     

高效溶剂萃取法提取黑果枸杞花色苷及其颜色稳定性研究

为了提高黑果枸杞花色苷的提取效率以及颜色稳定性,采用高效溶剂萃取法进行提取,考察静态萃取温度、乙醇浓度、静态萃取时间、静态萃取压力和循环次数对提取效果的影响,通过响应面法优化提取工艺,并对提取的花色苷溶液进行颜色稳定性研究。结果表明:最佳提取条件为温度48℃,乙醇浓度60%,提取时间4 min,静态萃取压力8 MPa,循环2次,在此条件下,花色苷的提取得率为1.989%;保存温度为4℃、pH值为2.5时,黑果枸杞花色苷溶液较为稳定。     

银杏叶多酚的机械力辅助提取及其体外抗氧化活性研究

为优化银杏叶多酚提取工艺,通过单因素试验考察填充率、球磨转速、球磨时间、乙醇浓度、料液比、提取温度、提取时间七个因素对机械力辅助提取银杏叶多酚得率的影响,以银杏叶多酚得率为响应值,采用Box-Benhnken三因素三水平响应面设计优化工艺,同时比较了4种提取方法对银杏叶多酚提取得率和抗氧化活性的差异。结果表明,机械力辅助提取银杏叶多酚的最佳工艺条件为:填充率26%、球磨转速为400rpm、球磨时间为15min。在此条件下,银杏叶多酚的得率为7.33%。机械力辅助乙醇提取银杏叶多酚得率低于碱水提取法,但是抗氧化活性高于碱水法提取的银杏叶多酚;抗氧化活性与乙醇回流法提取的银杏叶多酚相当,但是提取得率高于乙醇回流法。此提取工艺高效可行,具有一定的参考价值。     

重金属污染土壤总DNA提取方法的研究——土壤预处理和硫酸铵铝在DNA提取中的应用

【目的】从土壤中获得高纯度、高得率和完整性好的总DNA,为重金属污染土壤微生物群落多样性的分析奠定基础。【方法】将一定浓度的硫酸铵铝增补入DNA提取液中,分别联合不同方式的土壤预处理,对所提取的土壤总DNA进行完整性、纯度和得率分析。【结果】TENP-AlNH4(SO4)2法、ABG-AlNH4(SO4)2法、Wash-AlNH4(SO4)2法和试剂盒4种提取方法获得的DNA片段均在23 kb左右,总DNA完整;Wash-AlNH4(SO4)2法提取的DNA纯度较高,A260/A230达到2.00,A260/A280达到1.62;ABG-AlNH4(SO4)2法的DNA得率最高,达到1 010μg/g土壤;这两种方法提取的DNA在纯度和浓度上均达到后续PCR等分子实验要求。通过扩增提取的土壤总DNA中16S rRNA基因,表明合适浓度的硫酸铵铝能有效去除土壤中的PCR干扰因子。【结论】本研究将土壤的预处理和一定浓度的硫酸铵铝联合使用,获得理想的重金属污染土壤的总DNA。     

不同方法提取组培百里香精油质量及成分的比较分析

采用水蒸气蒸馏法、有机溶剂萃取法、CO2超临界萃取法3种提取方法提取组培百里香精油,比较分析精油得率、精油化学成分以及相对含量,以期得出最佳提取方法。结果表明：水蒸气蒸馏法提取的百里香精油得率为O．21％,主要化学成分为：百里酚（36．53％）、间伞花烃（14．13％）、松油烯（8．09％）和石竹烯（4．14％）;有机溶剂萃取法提取的精油得率为0．19％,主要化学成分为：1,2-苯二甲酸-单-2-乙基己基酯（55．23％）、百里酚（873％）、松油烯（5．23％）;CO2超临界萃取法提取的精油得率为0．27％,主要化学成分为：百里酚（26．68％）、3-苯基-2-丙烯酸-甲酯（21．55％）、间伞花烃（9．69％）。从精油得率、精油质量以及精油主要化学成分综合比较3种方法,水蒸气蒸馏法是提取百里香精油的最佳方法。     

花椒籽黑色素提取和脱蛋白技术研究

采用二次回归正交旋转组合试验优化了花椒籽黑色素的浸提工艺,并用蛋白酶酶解-Sevag法联用脱除花椒籽黑色素中的蛋白.结果表明:影响花椒籽黑色素提取效果的因素依次为温度>NaOH浓度>料液比,花椒籽黑色素提取的优化工艺参数为NaOH浓度为1.20 mol/L,料液比为1∶24.64,温度为70℃下提取2 h,共2次,所得花椒籽色素粗品为棕黑色无定型粉末,得率为6.1%,色价为201.62,蛋白质含量为44.83%~48.63%.碱性蛋白酶脱蛋白条件为温度50℃,pH 9,加酶量为粗色素溶液(浓度为1 mg/mL)体积的6%,再用Sevag法处理3次,蛋白质脱除率可达81.23%,花椒籽黑色素色价可提高1.5倍.     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.