Kinetics of Growth and Nutrient Consumption in the Culture of Trichosanthes kirilowii Hairy Root

IntroductionThe hairy roots produced by Agrobacteriumrhizogenes infection are characterized by highgrowth rate and genetic stability. Thesegenetically transformed roots can produce similarhigher levels of secondary metabolites than intactplants[1] ,so hairy root cultures are a promisingmethod for producing valuable secondarymetabolites of many plants.Recently,two kindsof ribosome- inactivating proteins ( RIPs) [2 ] ,trichosanthin ( TCN ) [3 ] ,and TAP 2 9[4] wereidentified in Trichosanthes…     

Crocin Synthesis Mechanism in Crocus sativus

Saffron （Crocus sativus） cells can synthesize crocin, crocetin digentiobiosyl ester, in suspension cultures. The crocin family biosynthesis mechanism was studied using high pressure liquid chromatography （HPLC） to determinate the glucosyltransferase activity and to develop a method for synthesizing medicine from saffron cells. Previous studies indicated that two glucosyltransferases might be involved in the formation of crocetin glucosyl- and gentiobiosyl-esters. GTasel formed an ester bond between crocetin carboxyl groups and glucose moieties while GTase2 catalyzed the formation of glucosidic bonds with glucosyl ester groups at both ends of the molecule. These enzymes can catalyze the formation of crocetin glucosides in vitro. GTasel activity is higher during the first four days of crocin glucosides biosynthesis, but decreases after four days. The formation and accumulation of crocin increase during the first six days and stabilized on the eighth day.     

固液两步法的藏红花素生物合成

为提高现代生物技术生产藏红花素的产率和效率,该研究采取固液两步培养法将在固体培养基中获得的藏红花愈伤组织转移到液体培养基中进行生物合成,结果显示生物反应器比摇瓶培养更有利于生物量的积累,也更有利于2号藏红花素的合成。碳源、氮源和磷酸的消耗与藏红花素的合成密切相关。采取固液两步培养法可以有效解决藏红花素合成与藏红花素抑制细胞快速增殖的相互矛盾。该结果对具有抗癌作用的藏红花素产业化有重要意义。     

Morphological Transformation of Plant Cells in vitro and Its Effect on Plant Growth

Enhancement of cell growth in suspension cultures is urgently needed in plant cell culture engineering. This study investigates the relationship between morphological transformation and cell growth in callus and suspension cultures of saffron cells belonging to the cell line C96 induced from Crocus safivus L In the suspension culture, an unbalanced osmotic pressure between the intracell and extracell regions induced a large morphological transformation which affected normal division of the saffron cells. An increase in osmotic pressure caused by the addition of sucrose inhibits the vacuolation and shrinkage of cytoplasm in the cells. As the sucrose concentration increases, the total amount of accumulated biomass also increases. Besides the sucrose concentration, increased ionic strength and inoculation ratio also help restrain to a large extent the vacuolation and shrinkage of the cytoplasm in the suspended cells, which results in increased biomass. The conditions for optimal biomass are： Murashige and Skoog＇s （MS） medium with 40 g/L sucrose and 60% （v/v） inoculation ratio.     

紫杉细胞生长过程与营养物质消耗的动态研究

对紫杉 B10细胞系进行悬浮培养 ,并对其生长过程与营养物质的消耗过程进行了测定。结果显示 :紫衫细胞在改良 B5培养基中 ,对于碳源、硝态氮、磷以及钙、镁、钾等营养物质的消耗并不是均匀的 ,虽然培养液中的碳源和钙可以满足细胞生长速度的需要 ,但氮、磷、钾在细胞快速生长前期已经被消耗殆尽 ,后期开始出现镁离子含量不足。因此可以证明培养液中的氮、磷、钾含量不足是影响细胞快速增殖的主要因素     

雄兔背部皮下埋植慢释放雄激素药物的实验

将具有慢释放丙酸睾丸甾酮(testosterone propinete(TSP))的聚合物,即雄激素药物,植入摘除了双侧辜丸的雄兔背部皮下定期取血,测定其在体内外的释放水平。利用血球计数和组织切片等方法观测植入雄激素药物后兔子的健康状况。结果表明:雄激素药物在动物体内能长期、稳定地释放丙酸睾丸酮。实验结果与雄激素药物埋植于雄兔阴囊部位的实验结果作了对照分析。这一工作为雄激素药物多种形式的临床应用提供了依据。     

家蚕染色体的观察及核型初步分析

在改进家蚕染色体观察方法的基础上,首次以径率为参数进行了核型分析。将家蚕染色体分为三组;A组4对,B组12对,C组12对。     

用扣除杂交法分离藏红花苷合成相关基因的克隆

对藏红花苷合成的相关基因进行了初步分离与克隆实验研究,旨在分离与藏红花苷合成相关的特异性表达的cDNA克隆,为进一步从分子水平上研究藏红花素的合成机理奠定基础。实验采用经添加诱导子和合成前体、处于藏红花苷合成状态下的藏红花细胞和未添加诱导子和合成前体、处于生长状态的对照藏红花细胞为材料,采用扣除杂交法成功地分离到6条与藏红花苷合成相关的特异性表达的cDNA克隆。结果表明:其中一条与胡杨中由高盐环境引起的差异表达的一条mRNA的序列有较高的同源性。     

许俊德小说一瞥

<正> 据我的直观感觉和朋友们的描述,许俊德其人,绝对那么本本正正,也就是说从他身上你寻找不出一点别的什么东西来。在火车上,他不亚于一个刚走出一片小地方的迂讷而又不乏机警的青年,反过来,又很难把他与别人区别开来。我这样说,不是写许俊德的印象记,而是要给我阅读他的小说定下一个情绪氛围。在这样一个氛围中,我寻找进入他的小说的契机。近年来,许俊德拉拉杂杂发表小说10多万字。从题材和内容上分大致有以下几类:一是     

论华北“干槽”的形成

一、引言 地形扰动对大气环流及天气过程的影响是很重要的。很早就有人注意到气旋过山,在山背风坡形成减压区的事实,并且有许多不同的解释,虽然一系列的解释并不完满,但足以说明地形对天气过程的影响是为大家所注意的。又如落机山及西藏高原