Immunomodulation property of hexane fraction of leaves of Cinnamomum tamala Linn. in rats

The leaves of Cinnamomum tamala Linn. (CT) (Lauraceae) clinically used in Ayurveda as antidiabetic and diuretic, but no reports are available towards immunomodulating property. Its hexane fraction (CTH) was orally given to rats for 10 days and delayed type of hypersensitivity (DTH), antibody producton against sheep red blood cells (SRBCs), mitotic index in bone marrow cells and concanavalin A (Con A) mediated proliferation of lymphocytes were assessed. Further on 30 days treatment, change in body weight (BW), spleen weight, thymus weight, bone marrow cellularity and hematological changes were observed. It inhibited significantly the DTH response (IC₅₀ 1475 ± 57.19 mg kg^?1 BW), antibody production, suppressed mitotic index in bone marrow cells along with the suppression of lymphocyte proliferation against Con A (IC₅₀ 63.33 ± 1.95 µg mL^?1). In all experiments, cyclophasphamide and dexamethasone had been used as reference drug for in vivo and in vitro studies, respectively. On 30 days treatment, the CTH (800 mg kg^?1 BW and above) significantly suppressed growth rate, increase of spleen and thymus weight and low bone marrow cellularity. In hematological examination, it inhibited total white blood cell and lymphocytes count and increased per cent of polymorphs. Thus, it could be suggested that the fraction possesses immunosuppressive property at doses, higher than 800 mg kg^?1 BW in rats. Copyright © 2010 John Wiley & Sons, Ltd.     

不同土壤水分条件下香樟凋落叶覆盖对土壤碳氮循环的影响

凋落物作为森林生态系统碳库的重要组成部分对森林土壤碳、氮循环具有重要作用.为探讨香樟凋落叶对土壤碳、氮循环的影响,室内模拟研究了10%、20%和30% 3种土壤含水量条件下香樟凋落叶覆盖森林土壤中碳、氮元素的变化.结果表明: 3种含水量条件下香樟凋落叶覆盖均显著增加了土壤CO₂排放速率和土壤溶解性有机碳(WSOC)含量,但显著降低了土壤中硝态氮含量,表明香樟凋落叶覆盖能够增强土壤呼吸强度和碳矿化,抑制土壤硝化作用;香樟凋落叶覆盖能够显著增加10%含水量土壤中铵态氮含量,但降低了20%和30%含水量土壤铵态氮含量,表明香樟凋落叶覆盖对土壤铵态氮含量的影响与土壤含水量有关.香樟凋落叶中部分单萜烯浓度在不同土壤含水量条件下分别与土壤CO₂排放速率和铵态氮含量呈显著正相关,而与土壤WSOC和硝态氮含量呈显著负相关,说明香樟凋落叶覆盖对土壤碳、氮循环的影响可能与凋落叶中的单萜烯有关.     

Chemical Composition,Mosquito Larvicidal and Antimicrobial Activities,and Molecular Docking Study of Essential Oils of Cinnamomum melastomaceum,Neolitsea buisanensis and Uvaria microcarpa from Vietnam

The leaf oil compositions of two Lauraceae and one Annonaceae plants cultivated in Vietnam were analysed by GC/MS (gas chromatography-mass spectrometry) analysis. The leaf oil of the first Lauraceae plant Cinnamomum melastomaceum contained 34 identified compounds, in which benzyl benzoate (38.5 %), linalool (19.9 %), (E)-caryophyllene (10.5 %), and α-terpineol (6.9 %) were the major compounds. The leaves of the second Lauraceae plant Neolitsea buisanensis gave an oil with the main compounds (E)-β-ocimene (24.0 %), benzyl benzoate (15.8 %), bicyclogermacrene (14.9 %), and (E)-caryophyllene (6.3 %). The leaf oil of the Annonaceae plant Uvaria microcarpa consisted of the principal compounds (E)-caryophyllene (18.0 %), bicyclogermacrene (8.1 %), and δ-elemene (6.1 %). Two Lauraceae oil samples exhibited strong mosquito larvicidal activity against Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus with LC₅₀ and LD₉₀ values of less than 50 μg/mL. The Annonaceae oil sample showed strong antimicrobial activity against the fungus Aspergillus niger ATCC 1015 with the MIC (minimum inhibitory concentration) value of 32 μg/mL. In the docking approach, the major compounds (E)-caryophyllene, bicyclogermacrene, and benzyl benzoate interacted with the mosquito odorant-binding protein 3OGN, whereas (E)-caryophyllene, bicyclogermacrene, and δ-elemene also potentially interacted with the 4ZA5 protein of fungus A. niger.     

A geraniol-synthase gene from Cinnamomum tenuipilum

Geraniol may accumulate up to 86-98% of the leaf essential oils in geraniol chemotypes of the evergreen camphor tree Cinnamomum tenuipilum. A similarity-based cloning strategy yielded a cDNA clone that appeared to encode a terpene synthase and which could be phylogenetically grouped within the angiosperm monoterpene synthase/subfamily. After its expression in Escherichia coli and enzyme assay with prenyl diphosphates as substrates, the enzyme encoded by the putative C. tenuipilum monoterpene synthase gene was shown to specifically convert geranyl diphosphate to geraniol as a single product by GC-MS analysis. Biochemical characterization of the partially purified recombinant protein revealed a strong dependency for Mg2+ and Mn2+, and an apparent Michaelis constant of 55.8 microM for geranyl diphosphate. Thus, a new member of the monoterpene synthase family was identified and designated as CtGES. The genome contains a single copy of CtGES gene. Expression of CtGES was exclusively observed in the geraniol chemotype of C. tenuipilum. Furthermore, in situ hybridization analysis demonstrated that CtGES mRNA was localized in the oil cells of the leaves.     

厦门地区云南樟的引种与养护管理探究

本文以邓小平在厦门市园林植物园的手植树为例,对云南樟的生物学特性、资源分布及在厦门地区的引种情况进行分析,认为:厦门植物园内云南樟生长异常的重要原因是根系活动环境恶化;厦门南亚热带海岛气候条件是导致其速生、提前衰老的主要原因之一,并提出相应的养护管理措施。     

供氮和增温对倍增二氧化碳浓度下荫香叶片光合作用的影响

供给0～0.6 mg N的盆栽荫香(Cinnamomum burmannii)幼树分别生长在倍增CO ₂(+CO₂,731 μmol·mol^-1)和正常空气CO ₂浓度(CO ₂,365 μmol·mol^-1)的生长箱内,昼夜温度分别为25/23 ℃和32/25 ℃,自然光照下生长30 d.以生长在CO₂和25/23 ℃下的植株为对照研究增温和氮对+CO₂叶片光合作用的影响.结果表明,在+CO₂和25/23 ℃下无氮和氮处理植株的平均光合速率(Pnsat)较+CO₂和32/25 ℃下的叶片高5.1%,温度增高降低叶片Pnsat;而Pnsat随供氮而增高.在+CO₂条件下,生长在32/25 ℃下的叶片Rubisco最大羧化速率(Vcmax)和最大电子传递速率(Jmax)较25/23 ℃下的低(P＜0.05),温度增高降低+CO₂下叶片的Vcmax和Jmax在+CO2下叶片光合呼吸速率(Rp)较低,生长温度增高提升Rp.在CO₂下生长温度从25/23 ℃增至32/25 ℃,叶片的Rubisco含量(NR)和Rubisco活化中心浓度(M)降低,而供氮能增高NR和M.供氮能减缓温度增高对倍增CO₂下荫香叶片光合作用的限制.     

一种新型的油樟叶片总RNA提取方法

以油樟叶为试材,比较Trizol法、皂土法、CTAB法、Tris-SDS-异硫氰酸胍法等传统方案提取总RNA,发现效果都不理想.本文针对油樟叶片富含油脂、多酚、多糖的特点,开创性地使用了一种改良的总RNA提取流程:首次增加预处理液、乙酸乙酯抽提来减少油脂、多酚和多糖对裂解液粘稠度的影响,提取过程中使用二氯甲烷代替三氯甲烷增加对疏水性杂质的清除效果,使用混合型高盐溶液多次脱糖,结果表明使用改良的新型方法获得的油樟叶片总RNA条带清晰无明显降解,测得的A260/A280和OD260/OD230均在2.0左右,产物得率约580 μg/g,通过RT-PCR扩增出了油樟18S rRNA基因序长为113bp的特异条带,说明这种改良的新型方法获得的RNA完整性、纯度和产率都远高于常规RNA提取方法,研究探索出一种新型油樟叶片总RNA的提取方法.     

米槁组织培养不定芽发生与继代增殖

该研究以米槁的带腋芽茎段为实验材料,建立米槁不定芽诱导及增殖培养体系,探究不同消毒时间、取材时间及不同激素种类和浓度配比条件对米槁带芽茎段不定芽诱导及增殖的影响。结果表明：(1)外植体最适消毒方式为75%酒精30 s + 0.1% HgCl₂ 6.5 min,11月为外植体取材进行消毒的最佳时期。(2)最适不定芽诱导培养基为MS + 3.0 mg/L 6 BA + 0.3 mg/L IBA + 6.5 g/L琼脂+ 30 g/L蔗糖,不定芽诱导率可达到81.24%;6 BA和NAA均能促进米槁不定芽的增殖,且NAA是不定芽增殖的主要影响因素。(3)最适不定芽增殖培养基为MS + 0.1 mg/L 6 BA + 1.0 mg/L NAA + 0.3 g/L AC + 6.5 g/L琼脂 + 30 g/L蔗糖,不定芽平均增殖系数达到2.79。该研究基本建立了米槁不定芽诱导及增殖培养体系,为其深层次的资源开发、利用及快速繁殖提供了一条新的路径。     

芳樟不同无性系叶片光合色素含量及叶绿素荧光参数分析

对18个芳樟[Cinnamomum camphora (L.) Presl]无性系叶片光合色素含量和叶绿素荧光参数进行了测定,并对各参数的相关性进行了分析;基于上述测定结果对供试的18个芳樟无性系进行了聚类分析.结果表明:芳樟不同无性系叶片叶绿素a、叶绿素b及类胡萝卜素含量分别为0.60～2.26、0.24～1.15和0.14～0.50mg· g-1,差异较大,部分无性系间叶绿素a和b以及类胡萝卜素含量差异达显著水平;其中,无性系BT2叶片的叶绿素a含量在18个无性系中最高,叶绿素b及类胡萝卜素的含量也较高.各无性系间叶片的初始荧光(Fo)、PSⅡ最大光化学效率(Fv/Fm)、PSⅡ潜在活性(Fv/Fo)、PSⅡ电子传递情况(Fm/Fo)、光化学淬灭系数(Qp)、非光化学淬灭系数(NPQ)和PSⅡ实际光化学效率(Qy)差异明显,且部分无性系间的差异达显著水平;各无性系间的最大荧光(Fm)、可变荧光(Fv)和荧光下降比值(Rfd)差异不显著.在各叶绿素荧光参数中,Fo与Fm显著正相关;Fm与Fv、Fv/Fm、Fv/ Fo、Fm/Fo以及Fv/Fm与Fv、Fv/Fo、Fm/Fo、Qy间均存在极显著正相关,其中Fv/Fm与Fv/ Fo、Fm/Fo的相关系数均达0.98;Qp与NPQ、Rfd呈极显著正相关,与其他参数则总体上呈负相关;Qy与Fm、Fv、Fv/Fm、Fv/Fo、Fm/Fo以及Rfd与NPQ、Qp、Qy均存在显著或极显著正相关.采用欧氏距离法,可将18个无性系划分为2类:第1类包含16个无性系;第2类仅包含无性系PC5和WP1.第1类又可进一步划分为2个亚类:第1亚类仅包含无性系BY2;第2亚类共包含15个无性系,其中的BT1与BT2距离最短,光合生理特征最接近.根据研究结果,初步推断芳樟各无性系叶片的潜在光化学活性和电子传递情况共同影响PSⅡ光能转换效率;无性系116、187、BT1和MD1对光能的利用率较高;无性系BT2则具有良好的光合生理性能.