一株产紫杉醇的红豆杉内生真菌的分离鉴定

用组织研磨涂布法对中国红豆杉中产紫杉醇的内生真菌进行分离,得到45株内生真菌;通过形态学和分子生物学手段对一株产紫杉醇的菌株Tax-4进行鉴定,其结果为黑团壳属(Massaria)。表明从中国红豆杉中分离得到了一株产紫杉醇的黑团壳属内生真菌,丰富了产紫杉醇内生真菌的资源。     

紫杉醇产生菌的筛选与发酵条件的调控

采用稀释倒平板法分别从云南红豆杉和南方红豆杉中分离出230余株内生真菌,经薄层层析、紫外及HPLC分析初步筛选,确定有5株表现出产紫杉醇的特性,其中1株真菌产率较高,约为1 mg/L.产紫杉醇的内生真菌菌丝体生长和紫杉醇积累之间存在相反的关系.低浓度乙酸铵(＜0.01 mmol/L)有利于菌丝体生长,不利于紫杉醇积累;较高浓度的乙酸铵不利于菌丝体生长而有利于紫杉醇积累.较高浓度的苯丙氨酸和酒石酸铵(＞0.05 mmol/L)有利于菌丝体生长,不利于紫杉醇积累;较低浓度的苯丙氨酸和酒石酸铵不利于菌丝体生长而有利于紫杉醇积累.亮氨酸对菌丝体生长和紫杉醇积累的影响很小;苯甲酸钠抑制菌丝体的生长和紫杉醇的积累.     

一株产紫杉醇真菌发酵条件的研究

研究了在一株产紫杉醇真菌的发酵培养中，初始糖浓度、碳源、氮源和前体饲喂对生物量和紫杉醇合成的影响。结果表明，一定氮源和前体饲喂对紫杉醇产量提高有显促进作用。在发酵过程中补加糖也有一定影响。     

南方红豆杉中产紫杉醇内生真菌的分离和筛选

从南方红豆杉中分离得到21株内生真菌,在PDA液体培养基中发酵后经HPLC检测,发现有3株能够产生紫杉醇,它们是XT5(Ectostromasp.)、XT2(botrytissp.)和XT17(Papulasporasp.),其紫杉醇产率分别是276.75μg/L、161.24μg/L和10.25μg/L.     

一株柏树内生真菌产生抗肿瘤药物紫杉醇

报道了一株从柏树中分离到的产抗癌药物紫杉醇的菌株,样品采自江苏,是第一例柏树内生菌产紫杉醇的报道,表明产紫杉醇真菌的多样性.简化和改进了提取紫杉醇的方法,可以快速得到一定量的紫杉醇满足TLC分析的需要,该方法提高了处理样品的速度,节省了时间和试剂消耗等,适用于大量样品的初筛.     

不同诱导子对曼地亚红豆杉内生真菌产紫杉醇的影响

从曼地亚红豆杉树皮中分离得到1株链格孢属(Alternaria sp.)内生真菌MF5。初期马铃薯葡萄糖(PD)培养基液体培养结果显示,MF5的发酵产物中检测到的紫杉醇质量浓度约为0.58 mg/L。为了提高MF5发酵产物中紫杉醇含量,考察添加CuSO_4、茉莉酸甲酯(MeJA)、赤霉素(GA_3)和红豆杉浸出液对MF5产紫杉醇的影响。结果表明:添加4%红豆杉浸出液,对MF5进行发酵培养,发酵产物中紫杉醇质量浓度为(2.47±0.07) mg/L;在此基础上,添加CuSO_4、MeJA、GA_3 3种诱导子也能够提高MF5产紫杉醇的能力,且同时添加3种诱导子时,MF5发酵物中紫杉醇含量最高,达到(12.58±0.80) mg/L。本研究证实了3种诱导子和红豆杉浸出液均可促进内生真菌代谢产生紫杉醇,为后续真菌发酵法生产紫杉醇打下基础。     

真菌诱导物对红豆杉细胞的影响

从红豆杉树皮、根皮中分离得到了十种真菌,由这些真菌制成的真菌诱导物加入到红豆杉细胞培养物中后,均能引起细胞发生过敏反应,细胞生长量下降,培养液ｐＨ值降低,但是各种真菌诱导物对紫杉醇合成的促进作用有很大的差别,最佳的情况为加入真菌诱导物后,紫杉醇的含量达到细胞干重的０．０７％．可为红豆杉细胞大规模培养提高紫杉醇的产量提供依据．     

高产紫杉醇真菌的筛选

从广西大学、广西北海、青岛崂山、兰州五泉山、秦皇陵、长白山、神农架等地采回松柏科植物的树枝,利用无菌分离技术从树枝中分离得到植物内共生真菌,用土豆（PDA）培养基培养并发酵,发酵产物经过抽滤、旋转蒸发等处理后采用高效液相色谱法对提取物进行检测.最终分离得到147株菌种,并筛选得到产紫杉醇真菌QHL（秦皇陵）002a,产量为77.4μg/L.     

枝状枝孢霉MD2的候选基因A00981的克隆及转基因菌株的构建

目的:为揭示真菌紫杉醇合成分子机制.方法:克隆了产紫杉醇内生真菌枝状枝孢霉MD2的候选基因A00981,该基因DNA和cDNA序列分别为969 bp和894 bp;其编码蛋白含有298个氨基酸、无跨膜结构和信号肽,与酰基辅酶A脱氢酶(ACAD)具有73%的一致性.进一步构建该基因的超表达载体pTFC-A00981,并转化枝状枝孢霉MD2,共获得9株转基因菌株.结果:Southern blot分析证明其中5株转基因菌株的外源基因是以单拷贝方式插入.结论:该结果为深入分析超表达候选基因A00981对枝状枝孢霉MD2紫杉烷类合成的影响奠定了基础.     

固态培养对产紫杉醇真菌小孢拟盘多毛孢次级代谢物生成影响

激活真菌基因组中沉默基因簇,可令其产生新的次生代谢产物,改变培养条件是有效的激活方法.本文研究了固态培养方法对一株产抗癌药物紫杉醇(Taxol)真菌——小孢拟盘多毛孢(Pestalotiopsis microspora)次级代谢产物生成的影响.实验发现固体发酵能够产生2种液体发酵中没有的产物,对其中一种产物进行了高效液相色谱(HPLC)分离纯化和定量分析.该物质的最高产量达到每克培养基质0.354mg,在HPLC谱上的保留时间和紫杉醇接近,值得进一步研究其结构和生物学活性.近年来,固体发酵技术以其独特性和环保优势,再次受到重视.本实验显示固态培养能够诱导该真菌产生2种稳定的次生代谢物,比单纯液体发酵更有优势.本研究还优化了固体发酵基质、发酵时间等条件,为进一步后续研究提供参考.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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