基于HPLC和NIRS建立快速检测盾叶薯蓣中3种皂苷含量的方法

建立一种快速检测盾叶薯蓣中三角叶薯蓣皂苷、盾叶新苷和薯蓣皂苷含量的方法。本研究以全国8个产地的盾叶薯蓣药材为研究对象,首先,利用HPLC-ELSD建立同时测定盾叶薯蓣中三角叶薯蓣皂苷、盾叶新苷及薯蓣皂苷含量的方法,并对不同产地的盾叶薯蓣药材进行三种皂苷的含量测定;其次,扫描盾叶薯蓣药材样品的近红外光谱,分别将盾叶薯蓣药材校正集样品的三种皂苷含量作为参考值,结合其近红外光谱图,以内部交叉验证决定系数(R~2)、校正均方根偏差(RMSEC)、预测均方根偏差(RMSEP)及预测性能指数(PI)作为评价所建定量检测模型性能的指标,利用TQ8.0分析软件结合偏最小二乘法(PLS),通过光谱预处理方法筛选、建模波段及主成分数的确定分别建立盾叶薯蓣药材中三种皂苷含量的快速检测模型;最后,分别利用验证集样品对所建三种皂苷检测模型的预测准确性进行检验。盾叶薯蓣样品中三角叶薯蓣皂苷、盾叶新苷和薯蓣皂苷含量测定方法经考察符合定量分析的要求;盾叶薯蓣药材中三角叶薯蓣皂苷定量检测模型的R~2为0.981 17、RMSEC为0.086 3、RMSEP为0.063 8、PI为90.5;盾叶新苷定量检测模型的R~2为0.982 64、RMSEC为0.042 0、RMSEP为0.027 4、PI为91.1;薯蓣皂苷定量检测模型的R~2为0.943 64、RMSEC为0.009 90、RMSEP为0.005 41、PI为85.8;经统计学检验,三个模型对三种皂苷的预测值与实测值之间无显著性差异。该方法可以相对快速、准确测定盾叶薯蓣中三角叶薯蓣皂苷、盾叶新苷及薯蓣皂苷的含量,为盾叶薯蓣药材质量的快速评价提供依据。     

盾叶薯蓣内生菌研究进展

植物内生菌是与植物协同进化的一大类微生物种群,具有抵抗病原微生物、促进宿主生长、产与宿主相似的次生代谢物等多种有益特性,是宝贵的生物资源库。盾叶薯蓣具有很高的药用价值,也是多种激素类药物合成前体的主要植物来源。从盾叶薯蓣植物分离具有有益特性的内生菌成为近年内生菌研究的热点。本文从盾叶薯蓣内生菌的分离鉴定方法和盾叶薯蓣内生菌的特性两个方面概述了近年来盾叶薯蓣内生菌的研究现状,以期为盾叶薯蓣内生菌的进一步研究开发提供参考。     

内生镰刀菌Dzf17多糖对盾叶薯蓣培养物薯蓣皂苷元积累的促进作用(英文)

从盾叶薯蓣(Dioscorea zingiberensis)内生镰刀菌(Fusarium oxysporum)Dzf17制备出胞外多糖(EPS)、菌丝水提多糖(WPS)和菌丝碱提多糖(SPS),研究了这3种多糖对盾叶薯蓣幼苗和细胞培养物薯蓣皂苷元积累的影响。3种多糖中,菌丝水提多糖对盾叶薯蓣幼苗和细胞培养物薯蓣皂苷元的积累有最明显的促进作用。向培养基中添加20 mg/L的菌丝水提多糖培养盾叶薯蓣幼苗和细胞,薯蓣皂苷元的产率分别为10.04 mg/L和2.40mg/L,是对照的3.11倍和3.87倍。结果表明,可以利用内生镰刀菌Dzf17多糖有效提高盾叶薯蓣培养物中薯蓣皂苷元的产量。     

4种薯蓣属植物的分子鉴别和亲缘关系研究

为揭示薯蓣属植物的亲缘关系,根据叶绿体matK、rbcL、trnL-F和psbA-trnH序列片段,对小花盾叶薯蓣(Dioscorea sinopatviflora)、盾叶薯蓣(D.zingibiernsis)、黄独(D.bulbifera)和山药(D.polystachya)进行种间分子鉴别研究,并探讨这4个片段在薯蓣属植物系统发育上的意义。结果表明,4种薯蓣属植物共22份材料的matK、rbcL、trnL-F和psbA-trnH序列片段的长度分别为1026~1142 bp、1156~1178 bp、744~822 bp和355~599 bp。用PAUP 4.0b10和贝叶斯推断构建的系统发育树分析表明,云南的黄独与盾叶薯蓣的亲缘关系较近;小花盾叶薯蓣与盾叶薯蓣的亲缘关系很近;而非洲的黄独与云南的黄独的亲缘关系很远。但仅用这4个cpDNA片段还不能完全区分小花盾叶薯蓣和盾叶薯蓣,这说明基于这4个序列片段的系统发育证据与4种薯蓣属植物属内的分类划分并不十分吻合。     

盾叶薯蓣响应低磷胁迫的生理代谢及基因表达特征分析

为探讨盾叶薯蓣在低磷胁迫下的生理变化、甾体皂苷类成分代谢及基因表达的响应特征，本研究选取河南南阳产盾叶薯蓣进行模拟低磷胁迫实验，在不同时期对根际基质中的磷含量(全磷、速效磷、磷酸铝盐、磷酸铁盐、磷酸钙盐)和土壤酸性磷酸酶(soil acid phosphatase, S-ACP)活性、植株根系发育特征(总根长、总投影面积、总表面积),各部位过氧化物酶(peroxidase, POD)、超氧化物歧化酶(superoxide dismutase, SOD)活性及甾体皂苷类成分含量等指标进行分析，确定盾叶薯蓣响应低磷胁迫的关键时期，并利用RNA-Seq测序对关键时期盾叶薯蓣根茎、叶片、地上茎3个部位中的基因表达特征进行分析。研究发现低磷胁迫处理后盾叶薯蓣根际基质中易吸收态磷含量显著降低，其抗氧化酶(POD、SOD)与酸性磷酸酶活性均显著升高，根系发育受阻；低磷胁迫可明显影响盾叶薯蓣中甾体皂苷的合成与积累，且不同部位响应特征不同；胁迫初期为盾叶薯蓣响应低磷胁迫的关键时期；响应低磷胁迫关键时期的盾叶薯蓣基因表达存在明显的组织特异性，对三个处理组不同部位基因表达量与代谢通路进行分析，分别从盾叶薯蓣...     

4种薯蓣属植物的psbA-trnH片段序列分析

对4种薯蓣属(Dioscorea)植物——小花盾叶薯蓣(D.sinoparviflora C.T.Ting.)、盾叶薯蓣(D.zingiberensis C.H Wright.)、黄独(D.bulbifera L.)和薯蓣(D.polystachya Turczaninow) 共22个植物类群的叶绿体psbA-trnH基因区进行PCR扩增并测序,获得了该区间的完整序列,小花盾叶薯蓣的psbA-trnH片段全长589~593 bp,盾叶薯蓣全长为575~599 bp,黄独全长为372 bp,薯蓣全长为355~368 bp。将所得序列用Bayesian推断其系统发育关系,结果发现psbA-trnH片段不能够完全区分4种薯蓣属植物种间和种内的各个分类群(不同产地),且不能区分盾叶薯蓣与小花盾叶薯蓣;推测薯蓣的演变过程可能与人工驯化有关,黄独与栽培薯蓣的亲缘关系较近,而与野生薯蓣的亲缘关系较远。     

小花盾叶薯蓣减数分裂与雄配子发育细胞学观察

运用压片法对小花盾叶薯蓣(Discorea parviflora C.T.Ting)小孢子减数分裂与雄配子体发育进行研究.结果表明:小花盾叶薯蓣细胞减数分裂中期Ⅱ染色体排列主要有4种类型:平行型、"八"字型、垂直(同面)、垂直(异面);四分体有3种类型:左右对称型、四面体型、交叉型;小花盾叶薯蓣雄配子发育可分为5个时期:单核居中期、单核靠边期、单核后期、双核初期和双核期.同时型胞质分裂和2.细胞型花粉证实了小花盾叶薯蓣所在薯蓣科是较原始的被子植物;小花盾叶薯蓣减数分裂中期Ⅱ染色体排列多样性与2n配子发生无关.     

药源植物盾叶薯蓣甾体皂苷及皂苷元的研究进展

盾叶薯蓣是重要的甾体激素类药源植物,其根茎中薯蓣皂苷元含量居薯蓣属植物之冠,为我国的特有种。为了寻找高含量的资源、筛选新的生理活性成分,多年来我国学者做了大量的研究工作。主要概括了盾叶薯蓣的资源分布、薯蓣皂苷元的提取工艺、化学成分、药理、含量测定等方面的研究。     

生物技术在薯蓣皂苷及其苷元生物合成中的应用

薯蓣皂苷及其苷元来源于药用植物盾叶薯蓣块茎,是合成甾体激素类药物的重要原料.由于野生盾叶薯蓣资源日渐枯竭及薯蓣皂苷及其苷元制备生产中的严重污染等问题,使其开发和生产面临严重的挑战.本文探讨了薯蓣皂苷及其苷元生产研究进展及存在的问题,概述了薯蓣皂苷及其苷元的代谢途径研究进展,展望了生物技术在薯蓣皂苷及其苷元生物合成中的应用前景.     

盾叶薯蓣的快速繁殖

对盾叶薯蓣（Ｄｉｏｓｃｏｒｅａ ｚｉｎｇｉｂｅｒｅｎｓｉｓ Ｗｒｉｇｈｔ）的外植体进行组织培养,筛选到诱导芽和诱导根的优化培养基和培养条件,建立了无性快速繁殖培养系,获得完整的培养植株并移栽成功。并用分光光度法初步分析了该诱导植株生长根的薯蓣皂素含量。     

文冠果种群繁殖方式及其在种群更新中的作用

以黄土高原丘陵区文冠果天然种群为研究对象,通过样地调查,分析了不同生境文冠果种群的有性和无性繁殖方式及其在种群更新中的地位.结果表明：不同坡向文冠果种群均能进行有性繁殖和无性繁殖,在阳坡、半阴坡生境,文冠果以有性繁殖为主,实生苗数量和占据空间的能力均大于萌生苗,有性繁殖在这2个生境中对种群的更新贡献较大;在半阳坡生境,文冠果以无性繁殖为主,萌生苗数量和占据空间的能力均大于实生苗,无性繁殖对种群更新的贡献较大.在相同生境条件下,文冠果幼苗生长状况均表现为萌生苗＞实生苗.同一起源的文冠果幼苗生长状况均表现为阳坡＞半阳坡＞半阴坡.2种繁殖的瓶颈期在实生苗的种子-幼苗阶段和萌生苗的幼树-成株阶段.黄土丘陵区文冠果种群在新生境定居下来的过程中,首先以实生苗入侵,当水分、光照、养分条件较好时,文冠果又以无性繁殖方式迅速占领空间,繁衍后代.     

Transthoracic Doppler echocardiography – noninvasive diagnostic window for coronary flow reserve assessment

Background

Strain Rate Imaging shows the filling phases of the left ventricle to consist of a wave of myocardial stretching, propagating from base to apex. The propagation velocity of the strain rate wave is reduced in delayed relaxation. This study examined the relation between the propagation velocity of strain rate in the myocardium and the propagation velocity of flow during early filling.

Methods

12 normal subjects and 13 patients with treated hypertension and normal systolic function were studied. Patients and controls differed significantly in diastolic early mitral flow measurements, peak early diastolic tissue velocity and peak early diastolic strain rate, showing delayed relaxation in the patient group. There were no significant differences in EF or diastolic diameter.

Results

Strain rate propagation velocity was reduced in the patient group while flow propagation velocity was increased. There was a negative correlation (R = -0.57) between strain rate propagation and deceleration time of the mitral flow E-wave (R = -0.51) and between strain rate propagation and flow propagation velocity and there was a positive correlation (R = 0.67) between the ratio between peak mitral flow velocity/strain rate propagation velocity and flow propagation velocity.

Conclusion

The present study shows strain rate propagation to be a measure of filling time, but flow propagation to be a function of both flow velocity and strain rate propagation. Thus flow propagation is not a simple index of diastolic function in delayed relaxation.     

Finite element modeling of impulsive excitation and shear wave propagation in an incompressible,transversely isotropic medium

Elastic properties of materials can be measured by observing shear wave propagation following localized, impulsive excitations and relating the propagation velocity to a model of the material. However, characterization of anisotropic materials is difficult because of the number of elasticity constants in the material model and the complex dependence of propagation velocity relative to the excitation axis, material symmetries, and propagation directions. In this study, we develop a model of wave propagation following impulsive excitation in an incompressible, transversely isotropic (TI) material such as muscle. Wave motion is described in terms of three propagation modes identified by their polarization relative to the material symmetry axis and propagation direction. Phase velocities for these propagation modes are expressed in terms of five elasticity constants needed to describe a general TI material, and also in terms of three constants after the application of two constraints that hold in the limit of an incompressible material. Group propagation velocities are derived from the phase velocities to describe the propagation of wave packets away from the excitation region following localized excitation. The theoretical model is compared to the results of finite element (FE) simulations performed using a nearly incompressible material model with the five elasticity constants chosen to preserve the essential properties of the material in the incompressible limit. Propagation velocities calculated from the FE displacement data show complex structure that agrees quantitatively with the theoretical model and demonstrates the possibility of measuring all three elasticity constants needed to characterize an incompressible, TI material.     

Study on Numerical Taxonomy of the Asexual Propagation of Scirpus planiculmis in Songliao Ecological Area

With theoretical and method ecological approach of numerical taxonomy,by selecting 8 relatively stable numerical characters in asexual propagation of Scirpus planiculmis in Songliao ecological area we have carried out the maximum synchronous branch classification for the investigation of the regularity in asexual propagation. A dendrogram of asexual propagation potency was established with maximum synchronous branch coefficients as numerical parameters and a developing level graph of asexual propagation characters in the matural propagation generations was drawn up on the basis of the total value of evolutionary steps. Thus the relativity between the ontogenesis of natural reproduction and the community competitive potency was unveiled. Based on the numerical parameters of leaped values in the asexual propagation of S. planiculmis,the key period of weed eradication was determined.     

楤木繁殖技术研究

对楤木繁殖技术进行了研究。楤木种子繁殖和扦插繁殖都用富含阔叶树腐叶的山基土作基质．播种在3月上旬进行可获70%左右的发芽率．扦插在2月上旬采用1年生枝条和2年生壮根作插穗成活率分别可达68％、76％左右。     

Signal propagation in feedforward neuronal networks with unreliable synapses

In this paper, we systematically investigate both the synfire propagation and firing rate propagation in feedforward neuronal network coupled in an all-to-all fashion. In contrast to most earlier work, where only reliable synaptic connections are considered, we mainly examine the effects of unreliable synapses on both types of neural activity propagation in this work. We first study networks composed of purely excitatory neurons. Our results show that both the successful transmission probability and excitatory synaptic strength largely influence the propagation of these two types of neural activities, and better tuning of these synaptic parameters makes the considered network support stable signal propagation. It is also found that noise has significant but different impacts on these two types of propagation. The additive Gaussian white noise has the tendency to reduce the precision of the synfire activity, whereas noise with appropriate intensity can enhance the performance of firing rate propagation. Further simulations indicate that the propagation dynamics of the considered neuronal network is not simply determined by the average amount of received neurotransmitter for each neuron in a time instant, but also largely influenced by the stochastic effect of neurotransmitter release. Second, we compare our results with those obtained in corresponding feedforward neuronal networks connected with reliable synapses but in a random coupling fashion. We confirm that some differences can be observed in these two different feedforward neuronal network models. Finally, we study the signal propagation in feedforward neuronal networks consisting of both excitatory and inhibitory neurons, and demonstrate that inhibition also plays an important role in signal propagation in the considered networks.     

文心兰试管苗丛生芽高效增殖体系的建立

分别采用细胞分裂素6-BA和Ad对文心兰试管苗增殖的作用进行研究,结果表明：在与0．2mg／L的NAA配合使用时,6-BA含量在2．0～4．0mg／L水平下的培养基较适合试管苗的增殖,最大增殖系数可达7．27,苗生长健壮,叶色鲜绿,适合进一步生根移栽;Ad在1．0～6．0mg／L的范围内增殖系数较小,苗生长缓慢、矮小。但有形成丛生苗的倾向;以2．0mg／L的6～BA和1．0mg／L的Ad组合使用,易形成丛生芽苗且苗体相对较小,增殖系数也较高;接种单株小苗较大苗易形成丛生芽苗;接种连体小芽苗,全部能形成丛生芽苗,增殖系数可达10．07,适合于进一步增殖使用。6-BA与Ad配合使用结合接种连体小芽苗可建立高效的丛生芽苗增殖体系,培养基最佳激素组合为MS 6-BA2．0mg／L Ad1．0mg／L NAA0．2mg／L 3％蔗糖 0．4％琼脂粉。     

The propagation potential. An axonal response with implications for scalp-recorded EEG

An electrophysiological response of axons, referred to as the "propagation potential," was investigated. The propagation potential is a sustained voltage that lasts as long as an action potential propagates between two widely spaced electrodes. The sign of the potential depends on the direction of action potential propagation. The electrode towards which the action potential is propagating is positive with respect to the electrode from which it is receding. For normal frog sciatic nerves the magnitude of the propagation potential was 17% of the peak of the extracellular action potential; TEA increased it to 32%. For normal earthworm median or lateral giant fibers it was 30%. A ripple pattern on the propagation potential was attributed to variation in resistance along the length of the worm. Cooling increased the duration of the propagation potential and attenuated the higher frequency components of the ripple pattern. Differential records from two widely spaced intracellular microelectrodes in the same axon differed from the propagation potential. The amplitude of the plateau relative to the peak was smaller, it decreased as the action potential propagated from one electrode site to the other, and the potential did not return to zero as rapidly as for extracellular records. When propagation was blocked by heat, the propagation potential slowly decayed. There was no ripple pattern during the decay. In a volume conductor, electrodes contacting the worm did not show the typical propagation potential, but electrodes located a few centimeters away from the worm did. Simple core-conductor models based on classical action potential theory did not reproduce the propagation potential. More complex, modified core-conductor models were needed to accurately simulate it. The results suggest that long, slowly conducting fibers can contribute to the scalp-recorded EEG.     

培养新生大鼠心肌细胞的电信号传导：多电极记录研究

利用多电极阵列同步记录技术对培养的新生大鼠单层心肌细胞的电活动进行胞外记录,观察心肌细胞在自发搏动和电刺激情况下信号在细胞间的传导模式。通过对记录信号的处理和分析,能获得诸如起搏细胞的数量和位置、动作电位的传导速度和途径以及不同起搏细胞间的相互影响等信息。研究还发现,心肌细胞阈下刺激会影响细胞的搏动和信号传导。     

ATMOSPHERIC AND UNDERWATER PROPAGATION OF BULLFROG VOCALIZATIONS

ABSTRACT

Male bullfrogs vocalize while partially submerged in shallow freshwater ponds. This imposes two potential propagation pathways, atmospheric and underwater, on transmission of their communication sounds. Propagation of pure tones, amplitude modulated (AM) broadband noise and natural calls was measured in air and underwater at three bullfrog breeding sites. In air, propagation losses were consistent with spherical spreading. No excess attenuation was observed for any tone frequency at any site. Both temporal envelope modulations and spectral cues are available to conspecific receivers at biologically realistic distances. The bullfrog's advertisement call is thus well adapted for transmission in air at the air/water interface. Underwater signal propagation differed at the three sites, consistent with substrate effects. Tone propagation showed the high-pass frequency window characteristic of shallow water. Broadband signals underwent propagation losses greater than expected by cylindrical spreading. Modulations of the envelope of natural calls remained discernible at distances where frequency-dependent propagation losses distorted the shape of the spectrum. Measurements of the propagation of the advertisement call emitted by a chorusing frog at the air/water interface confirm that periodicity cues embedded in the envelope are available to receivers both in air and underwater. High frequency cues available underwater overlap the maximal hearing sensitivity of larval conspecifics (tadpoles).