茶氨酸和没食子酸在普洱茶中的含量变化

建立高效液相色谱分析茶氨酸和没食子酸的方法,对由云南大叶茶（Camellia sinensis var．assamica）生产的晒青毛茶及其加工的普洱茶中二者的含量进行分析。结果表明,普洱茶中没食子酸的含量显著增高,而茶氨酸的含量则明显降低。茶氨酸和没食子酸的含量与原料的来源和质量,以及普洱茶的后发酵生产过程均有关系。对二者含量变化的机制进行了初步的讨论。     

普洱茶中功能性微生物的筛选及其对普洱茶感官品质的影响

普洱茶的渥堆发酵过程是以晒青毛茶的内含成分为基础,在微生物分泌的胞外酶及湿热作用下,发生一系列化学变化,最终形成普洱茶独特的风味。采用稀释涂布法,根据产酶微生物的特性,经过固体平板初筛和液体茶汤培养基复筛,从普洱茶中分离得到若干株产酶菌株,并从中挑选优良菌株接种普洱茶固体发酵,考察其对普洱茶感官品质的影响。经分子生物学鉴定,D13-16为米曲霉(Aspergillus oryzae),相似度为98.62%;GJ-02为米根霉(Rhizopus cryzae),相似度为98.57%;XW-10和DF-03均为黑曲霉(Aspergillus niger),相似度分别为99.10%和99.92%。结果表明:普洱茶香气的形成主要与蛋白酶产生菌有关,DB-16发酵后香气评分达到31分(对照28,总分40);汤色主要受多酚氧化酶产生菌的影响,DF-03发酵后汤色评分达到19分(对照12,总分20);而这四种功能性微生物均在不同程度上促进了普洱茶滋味的形成。     

贮藏条件对普洱茶品质成分的影响研究

将云南普洱茶放在不同的温度、水份和时间等条件下,观察外界的不同条件对普洱茶品质成分的影响。观察结果显示:水份和温度对普洱茶贮藏的品质成分影响最为显著,在相同的贮藏时间内,提升温度以及增加水份的含量,普洱茶的茶褐素会增加,出现变色,内含的成分会有所下降,如茶多酚和儿茶素等。经过实验证明,高温、低水分是普洱茶贮藏的较好条件,能够保持茶叶色泽和香味;而低温和高水份含量则会加速普洱茶的发霉。     

铁观音加工工序中的香气成分分析

采用顶空固相微萃取（HS-SPME）法分别萃取了铁观音堆青、炒青、烘焙三个工序中产生的香气,用气质连用仪（GC／MS）对这些香气进行定性定量分析。在 SPME 所收集的铁观音堆青、炒青、烘焙工序所产生的香气成分中分别鉴定出22、32和19种主要香气成分。其中,2-乙烯基-1,1-二甲基-3-亚甲基环己烷、苯乙腈、吲哚、2-乙基己醇、癸醛均出现在三道工序的香气中。     

话普洱，品普洱

近年来,随着市场的热炒,普洱茶承载了太多的沉重使命,历史的、文化的、艺术的、商业的,过去、现在、未来,甚至担负了云南茶产业做大做强的希望。于是乎,它的热是一浪高过一浪,厂家、商家蜂拥而现,各种俗称、概念风声水起,生茶、熟茶、传统普洱茶、现代普洱茶、普洱古茶、乔木普洱茶、台地普洱茶、大树普洱茶等让人眼花缭乱,茶叶界、商界、学术界众说纷纭,莫衷一是,大有“横看成岭侧成峰”之势。     

曲霉属真菌在普洱茶后发酵中的作用

为阐明微生物在普洱茶后发酵过程中的作用及其机制,本文进行了普洱茶温湿度试验,并利用从普洱茶后发酵堆中分离鉴定的优势曲霉属真菌,进行接种试验和专用菌剂的发酵生产试验.结果提示,只有在微生物的作用下,普洱茶才具特有的感官特性,曲霉属真菌能控制后发酵的过程,改变茶叶的感官特性.曲霉属真菌的种类及组合对普洱熟茶的茶多酚组成与含量,以及没食子酸、茶氨酸、咖啡因等特征成分的含量均有显著的影响.因此,应用专用菌剂进行后发酵生产,能加快普洱茶的熟化速度,提高发酵成功率,保证产品质量的稳定性,使普洱熟茶的规范化生产成为可能.     

我国西南元江大理茶的挥发性成分及其抗氧化活性

大理茶(Camellia taliensis)为山茶科山茶属茶组植物,主要分布于云南横断山脉澜沧江至伊洛瓦底江流域,即从云南的西部及西南部至缅甸北部.在其分布区,大理茶亦被称为野生大茶树,常用于加工制作茶叶.采用水蒸气蒸馏法、GC及GC/MS联用技术,首次对大理茶的鲜幼叶和鲜幼叶及老叶分别制成的绿茶中的挥发性成分进行提取和分析,共鉴定出91个化合物.研究结果表明,大理茶鲜幼叶的主要香气成分为棕榈酸(30.52％),亚油酸(19.82％),植醇(8.75％)和亚麻酸乙酯(2.54％)等有机酸及其酯和二萜类,而制成绿茶后,其主要香气成分则为芳樟醇(28.43％),脱氢芳樟醇(1.13％),α-松油醇(11.68％),橙花醇(4.92％)和香叶醇(12.34％)等单萜醇类成分.从大理茶鲜叶到由其制成的绿茶,香气成分发生了较大变化,形成了28种原鲜叶中未检测到的香气成分,其中,(Z,Z,Z)-9,12,15-十八烷三烯-1-醇的含量分别达到1.21％(幼叶绿茶)和11.2％(老叶绿茶),是大理茶制作的绿茶的特征香气成分.DPPH和ABTS+自由基清除实验结果显示大理茶鲜叶及其制成的绿茶的挥发性成分均具有一定的抗氧化活性,但均弱于茶多酚的抗氧化活性.     

普洱茶风味的青稞茶配方研制

以青稞、普洱茶为主要原料,以感官评价为评定指标,对青稞与茶汤料液比、浸泡时间、烘烤温度、烘烤时间4个主要影响因素进行单因素试验,采用Central Composite Design设计方法,对普洱茶风味青稞茶进行4因素5水平的响应面试验设计,得到普洱茶风味青稞茶的最佳配方。结果表明：普洱茶风味青稞茶的最佳配方为青稞与茶汤料液比6.5 g/100 mL、浸泡时间15 min、烘烤温度207℃、烘烤时间10.6 min,为普洱茶风味青稞茶的工业化生产提供了科学依据。     

云南普洱茶原料晒青毛茶的化学成分

从云南临沧地区生产普洱茶的原料晒青毛茶中分离到 2 1个化合物 ,通过波谱分析分别鉴定为 :(- )表儿茶素、 (- )表没食子儿茶素、 (- )表没食子儿茶素 - 3-O -没食子酸酯、 (- )表儿茶素 - 3-O -没食子酸酯、 (- )表阿福豆素 - 3-O -没食子酸酯、 ( )儿茶素、 (± )没食子儿茶素、槲皮素、槲皮素 - 3-O - β -D -葡萄吡喃糖甙、芦丁、山奈酚、山奈酚 - 3-O - β -D -葡萄吡喃糖甙、山奈酚 - 3-O -芦丁糖甙、小木麻黄素 (strictinin)、 1,6 -O -二没食子酰基 - β -D -葡萄吡喃糖、茶倍素、绿原酸、 3α ,5α -二羟基 - 4 -α -O -咖啡酰基金鸡纳酸、松柏醇甙、没食子酸和咖啡因     

我国西南元江大理茶的挥发性成分及其抗氧化活性(英文)

大理茶 ( Camellia taliensis) 为山茶科山茶属茶组植物,主要分布于云南横断山脉澜沧江至伊洛瓦底江流域,即从云南的西部及西南部至缅甸北部。在其分布区,大理茶亦被称为野生大茶树,常用于加工制作茶叶。采用水蒸气蒸馏法、GC 及 GC/MS 联用技术,首次对大理茶的鲜幼叶和鲜幼叶及老叶分别制成的绿茶中的挥发性成分进行提取和分析,共鉴定出 91 个化合物。研究结果表明,大理茶鲜幼叶的主要香气成分为棕榈酸 ( 30. 52%) ,亚油酸 ( 19. 82%) ,植醇 ( 8. 75%) 和亚麻酸乙酯 ( 2. 54%) 等有机酸及其酯和二萜类,而制成绿茶后,其主要香气成分则为芳樟醇 ( 28. 43%) ,脱氢芳樟醇 ( 1. 13%) ,α-松油醇( 11. 68%) ,橙花醇 ( 4. 92%) 和香叶醇 ( 12. 34%) 等单萜醇类成分。从大理茶鲜叶到由其制成的绿茶,香气成分发生了较大变化,形成了 28 种原鲜叶中未检测到的香气成分,其中,( Z,Z,Z) -9,12,15-十八烷三烯-1-醇的含量分别达到 1. 21% ( 幼叶绿茶) 和 11. 2% ( 老叶绿茶) ,是大理茶制作的绿茶的特征香气成分。DPPH 和 ABTS+自由基清除实验结果显示大理茶鲜叶及其制成的绿茶的挥发性成分均具有一定的抗氧化活性,但均弱于茶多酚的抗氧化活性。     

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.