亚抑菌浓度博落回生物碱对ExPEC主要外膜蛋白和II型T-A系统表达的影响

【背景】血根碱、白屈菜红碱、原阿片碱等生物碱是我国二类新兽药博落回散和博普总碱散的主要成分,具有广泛的药理作用。【目的】研究亚抑菌浓度血根碱、白屈菜红碱、原阿片碱对肠外致病性大肠杆菌(extraintestinal pathogenic Escherichia coli,ExPEC)主要外膜蛋白及其调控基因和Ⅱ型毒素-抗毒素(toxin-antitoxin,T-A)系统基因表达的影响,初步探讨博落回生物碱对ExPEC细菌生理活动影响的可能机制。【方法】比较不同Ⅱ型T-A系统基因yafON、hicAB、prlF-yhaV缺失的ExPEC对血根碱、白屈菜红碱、原阿片碱及抗生素的最小抑菌浓度;在1/2MIC亚抑菌浓度血根碱、白屈菜红碱、原阿片碱条件下,比较它们对ExPEC野生型(wild type,WT)菌株和外膜蛋白tolC缺失菌株(ΔtolC)的不同外膜蛋白基因ompC、ompX、tolC、ompF和调控基因acrR、rob、marR、rpoS、soxS表达的影响,以及对T-A系统基因yafON、hicAB、prlF-yhaV表达的影响。【结果】T-A系统hicAB和prlF-yhaV缺...     

The Level of Particulate Matter on Foliage Depends on the Distance from the Source of Emission

One of the most dangerous inhaled pollutants is particulate matter (PM). PM in inhaled air have a negative impact on human wellbeing and health, and may even cause deaths. Where pollutants have been emitted into the outdoor atmosphere, the only possible method for cleaning the air is through phytoremediation, a form of environmental biotechnology, where plants act as biological filters for pollutants. This study compared PM levels on the leaves of Tilia cordata Mill. trees growing in locations at increasing distances from the source of the PM emission. Significant differences between individual trees growing at a distance of between 3 m and 500 m from the road edge were found in: (i) the mass of PM that accumulated on leaves (total, surface, in-wax and the three determined size fractions) and (ii) the amount of waxes deposited on leaves.     

鱼腥草体细胞胚胎发生和植株再生

目的:利用鱼腥草的叶片和叶柄为材料,进行体细胞胚胎诱导及植株再生研究。方法:运用正交设计试验,考察在改良的MS固体培养基上添加不同种类、不同浓度的植物生长物质组合及其配比对鱼腥草愈伤组织诱导、体细胞胚胎发生及植株再生的影响。结果:鱼腥草无菌苗叶片在含有2,4-D 1.0 mg/L 6-BA 0.5 mg/L的改良MS培养基上能诱导出胚性愈伤组织;胚性愈伤组织在含有6-BA 1.0 mg/L的改良的MS培养基上诱导体细胞胚的发生;叶柄在含有6-BA 1.0 mg/L改良MS培养基上直接产生体细胞胚。体细胞胚在改良的MS NAA0.1 mg/L 6-BA 1.0 mg/L的培养基上能够快速繁殖,形成大量不定芽,在不加任何激素的MS培养基上就可以萌发出不定根,发育为成完整植株,在MS IBA 1.0 mg/L的固体培养基上能够形成大量的根。结论:建立了鱼腥草体细胞胚胎发生及植株再生的体系。     

同质园栽培下的湖南鱼腥草居群叶表型性状多样性分析

将采自湖南的20个鱼腥草(Houttuynia cordata Thunb.)居群栽培于同质园内,通过测定9个叶片表型性状和6个叶片相对性状,采用方差分析、变异系数、相关性分析、主成分分析以及聚类分析等方法,对鱼腥草居群叶片形态的变异特征进行研究。结果表明:(1)同质园栽培的20个鱼腥草居群叶片15个表型性状均存在显著差异,居群间差异大于居群内差异;(2)居群内叶性状的平均变异系数变化幅度为5.63%~9.08%,说明居群内多样性程度较低,其中株洲攸县居群(P16)变异系数最高(9.08%),怀化溆浦居群(P3)变异系数最小(5.63%);(3)15个叶性状的平均变异系数变化幅度为3.71%~10.28%,说明各性状的多样性程度也较低,其中叶面积变异系数最大(10.28%),叶宽与叶中部宽之比(W_2/W_4)的变异系数最小(3.71%);(4)相关性分析显示,叶面积与叶宽、叶中部宽、叶长、叶基至叶宽处的距离、叶柄长都呈现出显著正相关,与叶尖夹角呈显著负相关,而与叶基夹角关系不大;(5)叶片15个性状中前3个主成分的贡献率为83.66%,聚类分析可将20个居群划分为心形、小心形、狭心形和大心形4类,呈现出间断分布的地理格局;(6)同质园实验说明叶表型性状多样性主要是由遗传物质决定的,对其多样性分析能为优良种质资源的选育提供理论依据。     

三白草科的比较胚胎学研究

研究了裸蒴（ＧｙｍｎｏｔｈｅｃａｃｈｉｎｅｎｓｉｓＤｅｃｎｅ）胚胎的发育,同时对三白草（Ｓａｕｒｕｒｕｓｃｈｉｎｅｎｓｉｓ（Ｌｏｕｒ）．Ｂａｉｌｌ）和蕺菜（ＨｏｕｔｔｕｙｎｉａｃｏｒｄａｔａＴｈｕｎｂ．）的胚胎也进行了观察,并对三白草科（Ｓａｕｒｕｒａｃｅａｅ）各属间的胚胎学特征进行比较,以探讨三白草科的内的系统关系。裸蒴具腺质绒毡层。小孢子同时型,极少数小孢子弱细胞的减数分裂ＩＩ不进行,形成有壁     

三种植物对狭胸散白蚁的毒杀效果

测定并比较3种植物对狭胸散白蚁Reticulitermesangustatus的毒杀效果,为应用防治狭胸散白蚁提供理论基础。本文采用闹羊花Rhododendron molle、博落回Macleaya cordata、除虫菊Pyrethrum cinerariifolium 3种常见植物为药源,选取其药用部位打成粉末,以玉米芯粉为对照,以狭胸散白蚁为靶标,测试其毒杀作用、传毒效果和趋避效果。结果表明:对狭胸散白蚁的毒杀效果以除虫菊和闹羊花为最好,当药粉质量分数达到80%,实验第7天时闹羊花和除虫菊白蚁处理组校正死亡率达到100%。传毒效果以除虫菊相对最好。随着染毒时间延长和中毒白蚁数量的增加,传毒效率也相应提高。3种植物均有一定的驱避效果,且以博落回的趋避作用最小。因此,这3种植物可用于防治狭胸散白蚁。     

Shape of leaf photosynthetic electron transport versus temperature response curve is not constant along canopy light gradients in temperate deciduous trees

Responses of foliar light-saturated net assimilation rate (A_max), capacity for photosynthetic electron transport (J_max) and mitochondrial respiration rate (R_d) to long-term canopy light and temperature environment were investigated in a temperate deciduous canopy composed of Populus tremula L. in the upper (17–28 m) and of Tilia cordata Mill. in the lower canopy layer (4–17 m). Climatic measurements indicated that seasonal average daily maximum air temperature (T_max) was 5·5 °C (range 0·7–10·5 °C) higher in the top than in the bottom of the canopy, and strong positive correlations were observed between T_max and seasonal average integrated quantum flux density (Q_int), as well as between seasonal average daily mean temperature and Q_int. Because of changes in leaf dry mass and nitrogen per unit area, A_max, J_max, and R_d scaled positively with Q_int in both species at a common leaf temperature (T). According to J_max versus T response curves and dark chlorophyll fluorescence transients, photosynthetic electron transport was less heat resistant in P. tremula with optimum temperature of J_max, T_opt, of 33·5 ± 0·6 °C than in T. cordata with T_opt of 40·7 ± 0·6 °C. This difference was suggested to manifest evolutionary adaptation of photosynthetic electron transport to cooler environments in P. tremula, the range of which extends farther north than that in T. cordata. Possibly because of acclimation to long-term canopy temperature environment, T_opt was positively related to Q_int in P. tremula, foliage of which was also exposed to higher irradiances and temperatures, but not in T. cordata, in the canopy of which quantum flux densities and temperatures were lower, and gradients in the environmental factors less pronounced. Parallel to changes in T_opt, the activation energy for photosynthetic electron transport decreased with increasing Q_int in P. tremula, indicating that J_max of leaves acclimated to colder environment was more responsive to T in lower temperatures than that of high T acclimated leaves. Similar alterations in the activation energy for mitochondrial respiration rate were also observed, indicating that acclimation to temperature of mitochondrial and chloroplastic electron transport proceeds in a co-ordinated manner, and possibly involves long-term changes in membrane fluidity properties. We conclude that, because of correlations between temperature and light, the shapes of J_max versus T, and R_d versus T response curves vary within tree canopies, and this needs to be taken account in modelling whole canopy photosynthesis.     

水青冈林中两种鹅耳枥种子萌发和幼苗的生存与生长（英文）

 千金榆(Carpinus cordata var．chinensis)和千筋树(Carpinus fargesiana)是四川省北部山地水青冈林中的两种主要落叶阔叶树。两种植物种子萌发和幼苗生存与生长的实验研究结果显示：千金榆种子秋季成熟落地后有一年多的休眠期,种子主要在落地后的第二和第三个生长季萌发;千筋树种子成熟落地后有的可在来年萌发,但大部分是在第二个生长季萌发;由于每2～3年两种树就有一个较大的结实年,每年都会有一些新的幼苗在林中出土;尽管两种树是耐荫的,但幼苗在较好光照条件下(如林窗)生存和生长明显好于在林冠遮荫的地方;施肥会加速幼苗的死亡,特别是在阴暗的林下,但在光照较好的条件下能促进幼苗的生长。结果说明两种鹅耳枥的幼苗可以在林下持续存在,但只有在较好的光照条件下,如稀疏的林冠下或林窗下才会有明显的净生长。     

CHEMICAL DEFENSE AGAINST HERBIVORY IN THE ANTARCTIC MARINE MACROALGAE IRIDAEA CORDATA AND PHYLLOPHORA ANTARCTICA (RHODOPHYCEAE)

Iridaea cordata (Turner) Bory and Phyllophora antarctica A. et E. S. Gepp (Gigartinales, Rhodophyceae) are common in many high-latitude, shallow benthic marine communities in Antarctica, but previous observations have indicated little or no exploitation by potential herbivores. We have measured retention of test disks over the mouths of the common Antarctic sea urchin Sterechinus neumayeri Meissner, and we have used this assay to examine potential chemical defenses in I. cordata and P. antarctica. Thallus disks of both macroalgal species were retained by the urchins for significantly shorter times than inert filter paper disks and much shorter times than paper disks with a feeding stimulant. Both nonpolar and polar extracts of each macroalgal species added to disks with a feeding stimulant significantly decreased retention times relative to controls. These results support the hypothesis that chemical defenses in I. cordata and P. antarctica play a role in deterring potential herbivores.     

Assessing the risk of Eccritotarsus eichhorniae to pickerelweed,Pontederia cordata in North America

The mirid Eccritotarsus eichhorniae is a newly described species with potential as a biological control agent for water hyacinth, Eichhornia crassipes, in North America. A series of quarantine-based studies quantified E. eichhorniae usage of Pontederia cordata with no-choice, adult choice, nymph choice, multi-generation, and impact tests. Although greater numbers of E. eichhorniae adults developed on E. crassipes in two separate no-choice trials, some E. eichhorniae were able to complete development on P. cordata in both trials. Adults showed a clear oviposition preference for E. crassipes and F₁ progeny reduced the mean relative growth rate of E. crassipes but not P. cordata. Naïve nymphs were more likely to leave P. cordata for E. crassipes but not all nymphs left P. cordata when given a choice. Both multi-generation trials showed a rapid increase in the density of adults and nymphs on E. crassipes over four to five generations while population densities on P. cordata did not change, indicating that this insect can maintain populations on this plant. The modest damage inflicted by a sibling species on E. crassipes, coupled with the ability of E. eichhorniae to persist on P. cordata, may pose an interpretation challenge to U.S. regulatory agencies concerned with non-target impacts by biological control agents. Another option for the continuing efforts to increase the biological control of E. crassipes is to prioritise the evaluation of other potential agents like Taosa longula Remes Lenicov (Homoptera: Dictopharidae) or Thrypticus truncatus Bickel and Hernández (Diptera: Dolichopodidae) over E. eichhorniae.