禾草内生真菌对其它微生物的影响研究进展

禾草内生真菌在宿主植物的茎叶等地上组织中普遍存在,不仅能够提高禾草对生物与非生物逆境的抗性,而且能够对周围环境中的不同微生物类群产生影响。主要总结了禾草Neotyphodium/Epichlo内生真菌对病原真菌、丛枝菌根真菌和土壤微生物的影响及其作用机理。发现禾草内生真菌普遍存在对病原真菌的抑制作用,而对丛枝菌根真菌存在不对称的竞争作用,且因种类而异。禾草内生真菌对土壤微生物群落的作用则会随着土壤类型和时间等外界因素发生变化。禾草内生真菌对不同类群微生物的影响机制主要包括:通过生态位竞争、抑菌物质分泌、诱导抗病性等对病原真菌造成影响;通过根系化学物质释放、营养元素调节、侵染条件差异等对丛枝菌根真菌造成影响;通过根际沉积物和凋落物等对土壤微生物群落造成影响。禾草内生真菌产生的生物碱能提高宿主植物对包括昆虫在内草食动物采食的抗性,影响病原菌的侵入、定殖和扩展;根组织分泌物中包含次生代谢产物能够抑制菌根真菌、土传病原真菌及其它土壤微生物的侵染与群落组成;也可能通过次生代谢物影响禾草的其它抗性。因此,禾草内生真菌在植物-微生物系统中的作用应该给予更多的关注和深入研究。     

光照强度和光周期对醉马草内生真菌共生体幼苗生长和生物碱积累的影响

该研究通过测定不同光周期(8、12、14和16h·d~(-1))和光照强度(1 500、2 500和3 500lux)处理下醉马草内生真菌共生体幼苗的形态指标以及叶绿素、可溶性糖、麦角酰胺和麦角新碱的含量,以明确醉马草内生真菌共生体幼苗生长和生物碱积累的最适光照条件,为醉马草内生真菌共生体的应用提供理论依据。结果发现:(1)醉马草内生真菌共生体幼苗株高、叶绿素和可溶性糖含量随着光照时间的延长而增加,并在光周期为16h·d~(-1)时显著(P0.05)高于其他处理;根长、单株分蘖数和单株生物量均先升高后降低,且均在14h·d~(-1)处理下达到最大值。(2)随着光照强度的增加,醉马草内生真菌共生体幼苗4个形态指标以及叶绿素和可溶性糖含量均呈增加的趋势,并在光照强度为3 500lux时均达到最大值。(3)随着处理时间的延长,醉马草内生真菌共生体幼苗麦角酰胺和麦角新碱的含量在不同光周期处理下均呈上升的趋势,并在光周期为12h·d~(-1)和光照强度为2 500lux处理下麦角酰胺和麦角新碱的含量均显著高于其他处理(P0.05),且在处理第15天时达到最大值。研究表明,适宜的光照环境能显著促进醉马草内生真菌共生体幼苗生长和生物碱的积累,并以12h·d~(-1)光周期和2 500lux光照处理下最有利于麦角酰胺和的麦角新碱积累。     

Ergot Alkaloid and Endogenous Hormones Quantities and Relationship in Epichloë Endophyte: Drunken Horse Grass are Affected by Altitude

Journal of Plant Growth Regulation - Achnatherum inebrians is rich in alkaloids (ergonovine and ergine) with analgesic activities and insect resistance activities and prevents animal feeding. Many...     

青海省冬虫夏草资源适宜性区划分析

冬虫夏草是青藏高原的珍稀物种,具有较高的药用和经济价值,然而其资源的数量特征、空间分布格局及适宜度尚不清晰。本研究以青海省冬虫夏草资源生境条件为依据,以海拔、植被、土壤、气温和降水量作为主要指标,利用地理信息系统(geographic information system,GIS)的空间分析方法对青海省冬虫夏草资源适宜性及空间分布进行分析,并用野外实地采样进行验证。研究表明：玉树州的玉树市、杂多县、称多县、曲麻莱县;果洛州的玛沁县、达日县、甘德县等区域多处在适宜区;海北州的祁连县、刚察县,黄南州的泽库县、河南县、同仁县,玉树州的治多县、囊谦县,海南州的兴海县、同德县、贵南县及其他产冬虫夏草县的部分区域为较适宜区;西宁市的大通县,海东市的互助县和海西州的低海拔地区为不适宜区。整个青藏高原具有冬虫夏草分布面积占当地县域国土面积的76.2%。在青海省具有冬虫夏草分布的地区(市/州)中,玉树州和果洛州冬虫夏草分布的面积占当地县域国土面积的88.3%-99.6%,海北州、海东市、海南州、海西州、黄南州和西宁市冬虫夏草分布面积占当地县域国土面积的30.2%-96.5%。综合区划图能比较真实地反映青海省冬虫夏草资源的空间分布格局,区划结果与实地调查结果相符,表明利用空间分析方法进行冬虫夏草资源的适宜性分布区域的划分是可行的,该研究为合理开发和科学利用冬虫夏草野生资源提供理论依据。     

Real-Time Three-Dimensional Echocardiography to Assess Right Ventricle Function in Patients with Pulmonary Hypertension

Background

The convenience and availability of real-time three-dimensional echocardiography (RT3DE) makes it an attractive candidate for assessing right ventricle function. However, the viability of RT3DE is not conclusive.

Aim of Study

This study aims to evaluate RT3DE relative to cardiac magnetic resonance and 2-dimensional echocardiography (2DE) for measuring right ventricular systolic function in patients with pulmonary hypertension.

Methods

Patients with pulmonary hypertension (n = 23) underwent cardiac magnetic resonance, 2DE, and RT3DE. Specifically, 2DE was used to measure the right ventricular index of myocardial performance (RIMP), fractional area change, tricuspid annular plane systolic excursion (TAPSE), and tissue Doppler-derived tricuspid annular systolic velocity (S′). Cardiac magnetic resonance and RT3DE were used to measure right ventricular end-diastolic volume (RVEDV) and end-systolic volume (RVESV). The right ventricular ejection fraction (RVEF) was calculated.

Results

Regarding the measurements taken by 2DE, RVEF positively correlated with fractional area change (r = 0.595, P = 0.003) and S′(r = 0.489, P = 0.018), and negatively correlated with RIMP (r = −0.745, P = 0.000). There was no association between RVEF and TAPSE (r = −0.029, P = 0.896). There existed a close correlation between the values of RVEDV, RVESV, and RVEF as measured by RT3DE and CMR respectively (P<0.001); Bland-Altmanan analyses showed good agreement between them.

Conclusion

RT3DE was a viable method for noninvasive, accurate assessment of right ventricular systolic function in patients with pulmonary hypertension.     

The four and a half LIM domain protein 2 interacts with and regulates the HERG channel

Protein-protein interactions are critical for protein trafficking, localization and the regulation of ion channels. The human ether-a-go-go-related gene (herg) encodes the alpha-subunit of the potassium channel underlying the rapid component of the cardiac delayed rectifier current. To identify the cellular proteins involved in the regulation of the HERG channel, a human heart cDNA library was screened using a yeast two-hybrid system, with the N-terminus of HERG as bait. The four and a half LIM domain protein 2 (FHL2) was identified as a potential HERG partner. The interaction between these two proteins was confirmed by co-immunoprecipitation and glutathione transferase pull-down assays and immunocytochemical analysis. The physiological implication of HERG-FHL2 interaction, assessed by whole-cell, patch-clamp electrophysiology experiments, showed a significant increase in the HERG current amplitude and a faster deactivation of the tail current in human embryonic kidney 293 cells co-expressing HERG and FHL2. These data indicate that FHL2 interacts with and regulates the HERG channel. Our findings may aid in the further understanding of the molecular basis of HERG channel diversity and arrhythmogenesis in the long-QT syndrome.     

基于act序列中国西部披碱草属植物所带内生真菌的系统演化

摘要:【目的】研究中国西部披碱草属植物(Elymus spp.)所带无性世代内生真菌的系统进化关系。【方法】克隆15条分离于中国西部披碱草属植物无性世代内生真菌肌动蛋白基因(act)序列,并与下载自GenBank中内生真菌的act序列共同构建系统进化树和网络结构拓扑图。【结果】供试无性世代内生真菌act序列均为单拷贝基因。系统进化关系表明,它们与分离于北美洲披碱草属植物的有性世代内生真菌Epichlo elymi存在不同的起源,而与分离于北美洲直芒草(Achnatherum eminens)的无性世代内生真菌Neotyphodium chisosum具有较近的亲缘关系。进一步研究发现,由北美洲直芒草无性世代内生真菌N.chisosum形成的单元型Hap 8与本研究菌株所组成的单元型Hap 3之间可能存在基因流。     

The regulation of the cardiac potassium channel (HERG) by caveolin-1

Protein-protein interaction plays a key role in the regulation of biological processes. The human potassium (HERG) channel is encoded by the ether-à-go-go-related gene (herg), and its activity may be regulated by association with other cellular proteins. To identify cellular proteins that might play a role in the regulation of the HERG channel, we screened a human heart cDNA library with the N terminus of HERG using a yeast 2-hybrid system, and identified caveolin-1 as a potential HERG partner. The interaction between these 2 proteins was confirmed by coimmunoprecipitation assay, and their overlapping subcellular localization was demonstrated by fluorescence immunocytochemistry. The physiologic implication of the protein-protein interaction was studied in whole-cell patch-clamp electrophysiology experiments. A significant increase in HERG current amplitude and a faster deactivation of tail current were observed in HEK293/HERG cells in a membrane lipid rafts disruption model and caveolin-1 knocked down cells by RNA interference. Alternatively, when caveolin-1 was overexpressed, the HERG current amplitude was significantly reduced and the tail current was deactivated more slowly. Taken together, these data indicate that HERG channels interact with caveolin-1 and are negatively regulated by this interaction. The finding from this study clearly demonstrates the regulatory role of caveolin-1 on HERG channels, and may help to understand biochemical events leading to arrhythmogenesis in the long QT syndrome in cardiac patients.