喜树碱和10-羟基喜树碱受喜树生长发育调控的不同特点

为了揭示喜树碱(camptothecin, CPT)和10-羟基喜树碱(10-hydroxycamptothecin, HCPT)在喜树(Camptotheca acuminata Decaisne)体内代谢的生理调控机制及这两种类似物之间的关系和作用,运用高效液相色谱技术对种子形成、成熟、萌发和幼苗生长过程中喜树碱和10-羟基喜树碱的代谢动态进行了全面的研究.结果表明,喜树碱相对稳定地存在于成熟和幼嫩的组织中;10-羟基喜树碱特异性地积累在乳熟期的种子、种芽的子叶、幼嫩的真叶等幼嫩组织中,随着组织的进一步发育和成熟,其含量快速减少,成熟组织中积累极少,并且这两种生物碱的代谢在时间和数量上都呈现出相互消长的特点,由此推断,这两种生物碱不同程度地受生长发育调控的特点可能与喜树的化学防御策略密切相关,并且,它们之间可以相互转化以充分利用有限的氮素资源.     

喜树果中喜树碱和10-羟基喜树碱的匀浆提取工艺

以喜树果为原料,对匀浆法提取喜树碱和10-羟基喜树碱的工艺进行了研究,确定了最佳的工艺条件：提取溶剂为体积分数55％的乙醇,匀浆时间为8min,料液比为1：15（g／mL）。在此工艺条件下,喜树碱和10-羟基喜树碱的提取率分别为0．801‰和0．546‰。将该法与超声提取、回流提取、常温冷浸提取、水浴振荡提取进行了比较,结果表明,匀浆提取具有得率高、省时间等方面的优势,是一种高效提取喜树碱和10．羟基喜树碱的方法。     

Characterization of sorption sites and differential stress response of microalgae isolates against tannery effluents from ranipet industrial area—An application towards phycoremediation

Phycoremediation ability of microalgae namely Oscillatoria acuminate and Phormidium irrigum were validated against the heavy metals from tannery effluent of Ranipet industrial area. The microalgae species were cultured in media containing tannery effluent in two different volumes and the parameters like specific growth rate, protein content and antioxidant enzyme activities were estimated. FTIR spectroscopy was carried out to know the sorption sites interaction. The antioxidant enzymes namely superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) contents were increased in microalgae species indicating the free radical scavenging mechanism under heavy metal stress. SOD activity was 0.502 and 0.378 units/gram fresh weight, CAT activity was 1.36 and 0.256 units/gram fresh weight, GSH activity was 1.286 and 1.232 units/gram fresh weight respectively in the effluent treated microalgae species. Bio sorption efficiency for Oscillatoria acuminate and Phormidium irrigum was 90% and 80% respectively. FTIR analysis revealed the interaction of microalgae species with chemical groups present in the tannery effluent. From the results, the microalgae Oscillatoria acuminate possess high antioxidant activity and bio sorption efficiency when compared to Phormidium irrigum and hence considered useful in treating heavy metals contaminated effluents.     

不同产地和生长季节喜树叶中喜树碱含量测定

喜树(Camptotheca acuminata)是我国特有抗癌植物。本文通过测定不同产地的喜树幼嫩叶和成熟叶中喜树碱含量表明,均以四川都江堰所产喜树叶中喜树碱含量最高。不同生长月份的喜树嫩叶中喜树碱含量成一条单峰曲线,以7月喜树嫩叶中喜树碱的含量最高。     

Cu2+对喜树愈伤细胞中喜树碱合成的影响

喜树碱是一种从木本植物喜树(Camptothecaacuminata)中分离得到的抗癌活性物质,通过细胞培养合成喜树碱是喜树碱生产的一条重要途径。研究Cu~(2 )对喜树愈伤细胞培养中喜树碱积累的影响,结果表明,在B5培养基中添加0.008mg/mLCuCl2时,对喜树愈伤细胞的生长没有明显影响,但是对喜树愈伤细胞合成喜树碱的促进作用最强,喜树碱含量比未诱导前增加了约30倍。Cu~(2 )阻止培养细胞后期过氧化物酶活力的下降,并抑制花青素的生成。与黑暗培养相比,光照条件下添加Cu~(2 )更利于喜树愈伤细胞诱导合成喜树碱。     

接种后共培养时间对丛枝菌根喜树幼苗喜树碱含量的影响

在前期工作中利用蜜色无梗囊霉(Acaulospora mellea)和根内球囊霉(Glomus intraradices)从接种时期角度分析了喜树碱含量与菌根形成过程对应关系的基础上,通过温室盆栽接种试验,继续观察了这两种丛枝菌根真菌接种后与喜树(Camptothecaacuminata)幼苗的共培养时间对喜树幼苗喜树碱积累的影响。分别用两种菌根真菌每隔7d接种一批喜树幼苗,第5批接种7 d后采样,获得菌根真菌与喜树幼苗共培养时间分别为35、28、21、14、7 d的喜树幼苗样品,测定了菌根浸染状况和喜树碱含量。结果表明:(1)接种两种丛枝菌根真菌均促进了喜树幼苗喜树碱的积累,表现为喜树碱含量和产量(单株幼苗所含的喜树碱量,喜树碱含量与幼苗生物量的乘积)的显著提高。(2)从接种后共培养时间的效果看,两种菌根幼苗各器官(根、茎、叶)及全株喜树碱含量和产量均呈现随着丛枝菌根真菌与喜树幼苗共培养时间的增加而增加的趋势。两种菌根幼苗的根和茎、根内球囊霉菌根幼苗的叶片和全株的的喜树碱含量和产量,在共培养时间增加至21 d时趋于稳定,而蜜色无梗囊霉菌根幼苗的叶片和全株的喜树碱含量和产量在共培养时间增加至28 d时达到最高,其后略有降低。(3)两种丛枝菌根真菌的侵染率和侵染强度同样随共培养时间的增加而增加,至共培养28 d后无显著变化。在一定共培养时间范围内,喜树碱含量和产量的变化与丛枝菌根真菌的侵染及菌根形成之间具有对应性。     

喜树内生放线菌多样性及抗菌活性评价

从采集于云南大学的喜树中分离到了90株内生放线菌,经16SrRNA基因序列分析鉴定,分布于6个科10个属。对所有分离到的菌株进行抗菌活性检测,发现33.4%的菌株有抗菌活性。通过PCR方法,检测了PKSⅠ、PKSⅡ和NRPS基因,阳性检出率分别为31.1%,48.9%和45.6%。     

喜树花序内性别表达及性别分配

 花序内性别表达和性别分配的差异在被子植物中非常普遍。常见的变化模式是: 在顺次开放的花序内, 从早开的花到晚开的花, 生殖结构大小和数量依次减少, 晚开的花偏向雄性。通常认为资源竞争和位置效应是形成这种差异的主要原因。在喜树(Camptotheca acuminata)的聚伞花序内, 早开的头状花序在花序直径、小花直径、短雄蕊长度、坐果率、果序重量等方面与晚开的头状花序差异显著。通过去除喜树聚伞花序一级或一级和二级头状花序来控制花序内的资源分配, 从而分析影
响喜树花序内花性状、性别分配及生殖能力的主要因子。结果显示, 去除部分头状花序后, 剩余头状花序的花序直径、小花直径明显增加, 短雄蕊长度明显缩短, 位置间差异消失; 而坐果率、果序重量的位置间差异依然显著。表明资源限制对花序直径、小花直径和短雄蕊长度等影响显著, 而坐果率和果序重量受位置效应影响明显。喜树雄全同株的性别分配可能是对特定生殖状况和资源状况适应的结果。     

喜树幼枝的喜树碱积累及其组织内定位

对喜树幼枝发育过程中各组织结构变化的观察和喜树碱含量的分析,以及荧光显微技术对喜树碱的定位研究,结果表明,幼茎和幼叶表面的单细胞腺毛和幼茎及幼叶内部由1～2层细胞包围而成的分泌道是喜树碱的主要积累部位.     

Synthesis and/or accumulation of bioactive molecules in the in vivo and in vitro root

Abstract

Roots of many species are studied because of the presence of high-value bioactive molecules, yet few studies have attempted to determine the biosynthetic pathways of these compounds or the way in which synthesis is regulated. The presence of secondary metabolites in the root does not necessarily mean that this organ is also the site of synthesis. Thus the identification of organ-specific intermediate precursors and key enzymes is important for understanding the biosynthetic pathway and the regulation of bioactive molecules. This knowledge could allow researchers to predict the suitability of in vitro systems, such as regenerated roots and hairy roots, for producing the molecules of interest. In the present review, the production of bioactive molecules in in vivo roots is compared to that in in vitro untransformed and transformed roots, concentrating on recent developments in the study of the biosynthesis of the anti-cancer alkaloid camptothecin in Camptotheca acuminata Decne. The results of a recent study performed in our laboratory on the production of camptothecin and other secondary metabolites in in vivo and in vitro C. acuminata roots are also presented.