超声辅助从柿叶中提取熊果酸的工艺研究

通过单因素实验,以熊果酸的提取率为指标,考察了柿叶中熊果酸超声提取过程的几个影响因素;并通过正交实验,对过程参数进行了优化。结果表明,各因素对熊果酸提取效果的影响程度从高到低分别是：乙醇体积分数→提取次数→提取时间→液固比;确定的最适提取条件为：体积分数95％乙醇溶液超声提取2次,每次40min,液固比为10：1。     

响应面法优化泡桐叶中熊果酸的超声波提取工艺

为探讨泡桐叶中熊果酸的超声波提取工艺,通过中心复合设计-响应面法研究乙醇浓度(X1)、液固比(X2)、超声波提取时间(X3)对泡桐叶中熊果酸提取得率的影响。结果表明,各因素对熊果酸得率的影响顺序为乙醇浓度(X1)超声波提取时间(X3)液固比(X2);超声波辅助提取泡桐叶中熊果酸的最优工艺条件为:乙醇浓度89%,液固比31 m L/g,超声时间37 min;在此条件下,熊果酸得率为14.80 mg/g,与预测值相近,二次回归模型预测性良好。     

苦瓜中苦瓜甾苷的提取工艺研究

本研究通过单因素实验和正交实验,采用HPTLC检测方法,以苦瓜甾苷浸提量为考察指标,对影响苦瓜甾苷提取效果的各因素进行了研究。结果表明各因素对苦瓜甾苷提取效果的影响程度从高到低依次为:乙醇浓度>固液比>浸提时间>浸提温度。确定了苦瓜甾苷的最佳提取工艺参数为乙醇浓度80%,浸提温度55℃,浸提时间5h,固液比1:10。     

超声波辅助提取盐地碱蓬红色素的工艺研究

为了探讨超声波对盐地碱蓬红色素提取效果的影响,为进一步提取纯化盐地碱蓬红色素提供一定的理论依据,通过单因素和正交实验,研究了不同提取时间、温度、液固比和功率下超声波辅助对盐地碱蓬红色素提取的影响.结果表明:各因素对红色素提取效果的影响程度依次为液田比>温度>功率>时间;最佳提取工艺条件为提取时间50 min,提取温度50℃,液固比15 mL/g,超声功率800 W.超声波对盐地碱蓬红色素的提取具有一定的促进作用.     

超声辅助酸水解提取山里红叶中牡荆素的工艺优化

采用正交法优化山里红叶中牡荆素的超声辅助提取工艺。通过盐酸浓度、提取时间、固液比、超声功率、超声温度、乙醇浓度6种影响因素的单因素实验,研究它们与牡荆素提取得率之间的规律趋势;应用正交设计优化试验,研究盐酸浓度、提取时间、固液比和超声功率对山里红叶提取牡荆素得率影响大小,并确定最佳提取工艺。研究结果表明：当盐酸浓度为2 mol·L^-1、提取时间为40 min,固液比为1：20、超声功率为500 W、超声温度为50℃、乙醇浓度为50%时,效果最佳,得率为2.603 mg·g^-1;盐酸浓度具有较大显著性,且各因素影响顺序为：盐酸浓度 > 超声功率> > 提取时间 > 固液比。     

水皂角多酚的提取工艺研究

本研究通过单因素实验和正交实验 ,以提取物中水皂角总多酚含量为考察指标 ,对影响水皂角多酚提取效果的各因素进行了研究。结果表明各因素对水皂角多酚提取效果的影响程度从高到低依次为 :浸提温度 >乙醇浓度 >固液比 >浸提时间。确定了水皂角多酚的最佳提取工艺为乙醇浓度 70 % ,浸提温度 70℃ ,浸提时间 5h ,固液比 1∶10。     

千年健总黄酮的超声提取工艺

为了研究千年健黄酮的超声提取工艺,通过单因素实验,研究了超声功率、超声时间、乙醇浓度、液固比等因素对黄酮得率的影响,利用正交试验对提取工艺进行优化。结果表明,各因素的影响次序为:超声功率乙醇浓度液固比超声时间,其最佳提取工艺条件为:超声功率为300W、超声时间15min、乙醇浓度50%、液固比30:1,最佳工艺条件下黄酮提取率为0.5868%。     

野西瓜低聚糖的提取及含量测定

目的:确定野西瓜低聚糖提取工艺参数并测定其含量.方法:对提取温度、提取时间、料液比和乙醇浓度进行了单因素和L9(34)正交试验;用分光光度法测定了野西瓜中低聚糖含量.结果:影响野西瓜低聚糖提取率的4个因素的影响程度依次为:提取时间>提取温度>乙醇浓度>料液比.最佳提取条件为:提取温度70℃、提取时间70min、料液比1/25、乙醇浓度80%,在此实验条件下低聚糖得率为3.70%.结论:实验结果为野西瓜低聚糖的进一步研究提供科学依据.     

响应面法优化苦丁茶熊果酸提取工艺及其抑菌活性研究

为优化苦丁茶熊果酸的提取工艺,并探讨其抑菌活性。在单因素试验基础上,通过响应面分析法,研究了液料比、提取温度、乙醇浓度对苦丁茶熊果酸得率的影响。以金黄色葡萄球菌、枯草芽孢杆菌、生孢梭菌、铜绿假单胞菌、大肠杆菌、白色念珠菌、黑曲霉为供试菌,探究了苦丁茶熊果酸的抑菌活性及最小抑菌浓度(Minimum inhibitory concentration,MIC)。结果表明,最优提取工艺为:液料比为17∶1(mL/g)、乙醇浓度为83%、提取温度83℃;抑菌实验表明,苦丁茶熊果酸对7种菌均有一定的抑制效果,对大肠杆菌、铜绿假单胞菌的MIC为6. 25 mg/mL,对生孢梭菌、金黄色葡萄球菌、枯草芽孢杆菌的MIC为12. 5 mg/mL,对白色念珠菌、黑曲霉的MIC为25 mg/mL。     

马尾松松针挥发油提取工艺研究

本文研究水蒸气蒸馏法提取马尾松松针挥发油的工艺。通过单因素试验考察液固比、提取时间、松针长度、浸泡时间4个因素对马尾松松针挥发油得率的影响,运用L9(34)正交试验探索最佳工艺条件。结果表明,浸泡时间对挥发油提取有显著影响(P=0.045),最佳时间为7 h;液固比、提取时间、松针长度无显著影响(P>0.05)。最佳工艺条件为液固比9∶1、提取时间3 h、松针长度5 mm、浸泡时间7 h,通过验证实验验证此工艺稳定可行。     

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.