三叶鬼针草与不同本地植物竞争对土壤 微生物和土壤养分的影响

入侵植物三叶鬼针草(Bidens pilosa)对我国农牧业生产造成了重大的损失。本文主要研究三叶鬼针草入侵与不同本地植物竞争对土壤微生物群落结构和土壤养分的影响。利用磷脂脂肪酸方法(phospholipid fatty acids, PLFAs)测定土壤微生物群落组成, 同时测定土壤养分和酶活性, 并利用Canoco4.5软件分析了土壤微生物、土壤养分和土壤酶活性的相关性。结果表明: (1)三叶鬼针草对革兰氏阳性菌、革兰氏阴性菌、丛枝菌根真菌等土壤微生物具有较强的聚集能力, 且其根际土壤聚集的微生物类群与本地植物种类密切相关。(2)三叶鬼针草入侵显著增加了入侵地土壤的有机碳含量, 降低了铵态氮的含量; 土壤中的速效钾、速效磷和硝态氮的含量则与本地植物种类密切相关。(3)相关性分析表明, 16:00和16:1 ω5c对铵态氮的含量影响较大, 而三叶鬼针草入侵地16:00和16:1 ω5c的含量显著高于裸土对照, 进而推测这一状况导致了铵态氮含量的降低。(4) 15:1 anteiso A和18:1 ω5c与速效钾的含量呈显著正相关, 而其含量在狗尾草(Setaria viridis)中显著高于其他处理, 三叶鬼针草与狗尾草混种处理中土壤中速效钾的含量高于其他处理。以上结果说明, 三叶鬼针草通过改变土壤微生物群落结构影响了土壤酶活性和土壤养分, 且这种改变与入侵地本地植物种类有关。     

枯草芽孢杆菌中一种新型双向启动子的功能鉴定

本研究旨在通过转录组分析预测的方法,由地衣芽孢杆菌中筛选获得一种新型双向启动子,鉴定其启动强度。以已知强组成型启动子pShuttle-09为对照,检测其对克劳氏芽孢杆菌碱性蛋白酶基因的表达活性。成功构建了3种重组碱性蛋白酶表达载体及对应的工程菌株。在新型启动子pLA和其反向启动子pLB调控转录下,克劳氏芽孢杆菌碱性蛋白酶表达活性达到164 U/mL和111 U/mL。结果表明,pLA的启动强度明显高于pShuttle-09和pLB,pLA启动子与pLB启动子均可表达碱性蛋白酶。从而为枯草芽孢杆菌表达系统中异源基因的表达提供一个新的方向,也为原核生物中共同表达两种基因提供了新的思路。     

HIV-protease inhibitors induce expression of suppressor of cytokine signaling-1 in insulin-sensitive tissues and promote insulin resistance and type 2 diabetes mellitus

Insulin resistance, hyperglycemia, and type 2 diabetes are among the sequelae of metabolic syndromes that occur in 60-80% of human immunodeficiency virus (HIV)-positive patients treated with HIV-protease inhibitors (PIs). Studies to elucidate the molecular mechanism(s) contributing to these changes, however, have mainly focused on acute, in vitro actions of PIs. Here, we examined the chronic (7 wk) in vivo effects of the PI indinavir (IDV) in male Zucker diabetic fatty (fa/fa) (ZDF) rats. IDV exposure accelerated the diabetic state and dramatically exacerbated hyperglycemia and oral glucose intolerance in the ZDF rats, compared with vehicle-treated ZDF rats. Oligonucleotide gene array analyses revealed upregulation of suppressor of cytokine signaling-1 (SOCS-1) expression in insulin-sensitive tissues of IDV rats. SOCS-1 is a known inducer of insulin resistance and diabetes, and immunoblotting analyses revealed increases in SOCS-1 protein expression in adipose, skeletal muscle, and liver tissues of IDV-administered ZDF rats. This was associated with increases in the upstream regulator TNF-alpha and downstream effector sterol regulatory element-binding protein-1 and a decrease in IRS-2. IDV and other PIs currently in clinical use induced the SOCS-1 signaling cascade also in L6 myotubes and 3T3-L1 adipocytes exposed acutely to PIs under normal culturing conditions and in tissues from Zucker wild-type lean control rats administered PIs for 3 wk, suggesting an effect of these drugs even in the absence of background hyperglycemia/hyperlipidemia. Our findings therefore indicate that induction of the SOCS-1 signaling cascade by PIs could be an important contributing factor in the development of metabolic dysregulation associated with long-term exposures to HIV-PIs.     

Pentamerization of single-domain antibodies from phage libraries: a novel strategy for the rapid generation of high-avidity antibody reagents

We describe a novel type of molecule in which single-domain antibodies (sdAbs) isolated from a nai;ve llama single domain antibody library are linked to an oligomerization domain to generate high-avidity, antigen-binding reagents. An sdAb is fused to the B-subunit of Escherichia coli verotoxin, or shiga-like toxin, which self-assembles to form a homopentamer and results in simultaneous sdAb pentamerization and introduction of avidity. Molecular modeling indicated that this fusion protein (PDB: 1OJF), termed pentabody, has structural flexibility for binding to surface-presented antigen. In the instance of an sdAb specific for a peptide antigen, pentamerization resulted in a dramatic increase in functional affinity for immobilized antigen. The pentabody was expressed in high yield in E.coli in a non-aggregated state, and exhibited excellent thermostability and protease resistance. This technology provides a relatively rapid means of generating novel antigen-binding molecules that bind strongly to immobilized antigen. It is expected that pentavalent sdAbs will have general applicability in proteomics, immunochemical staining, cancer diagnosis and other applications in which antigens are presented multivalently.     

唐家河自然保护区大熊猫种群数量及栖息地的移动

本文根据大熊猫季节性活动规律特点,应用海拔高度路线调查法,全面收集唐家河自然保护区大熊猫的比较新鲜粪便,计获１２４个粪样材料,提取ＤＮＡ作ＤＮＡ指纹图,经微机检测,保护区有大熊猫３７只,个体数量与粪样采集量之比为１∶３３５１４,有６个家系,雌兽２１只,雄兽１６只。并搞清了保护区生态环境质量,箭竹遭受病虫害的程度,洪水对栖息地的影响,特别对引起大熊猫数量减少及栖息地移动等原因,作了较为详细的分析。     

滇东南老君山自然保护区的蕨类植物资源

在野外实地调查、标本采集、标本鉴定和文献资料整理的基础上,对滇东南老君山自然保护区的蕨类植物资源进行研究。目前共知有蕨类植物44科,115属,259种(包括变种和变型),其中有国家珍稀濒危保护蕨类植物7种。按照其用途将这些植物划分为药用、观赏、食用、指示、化工原料、编织、饲料和绿肥等7种类型。最后,讨论了其开发利用现状及前景。     

Invasion biology of Australian ectomycorrhizal fungi introduced with eucalypt plantations into the Iberian Peninsula

In the last two centuries, several species of Australian eucalypts (e.g. Eucalyptus camaldulensis and E.␣globulus) were introduced into the Iberian Peninsula for the production of paper pulp. The effects of the introduction of exotic root-symbitotic fungi together with the eucalypts have received little attention. During the past years, we have investigated the biology of ectomycorrhizal fungi in eucalypt plantations in the Iberian Peninsula. In the plantations studied, we found fruit bodies of several Australian ectomycorrhizal fungi and identified their ectomycorrhizas with DNA molecular markers. The most frequent species were Hydnangium carneum, Hymenogaster albus, Hysterangium inflatum, Labyrinthomyces donkii, Laccaria fraterna, Pisolithus albus, P. microcarpus, Rhulandiella berolinensis, Setchelliogaster rheophyllus, and Tricholoma eucalypticum. These fungi were likely brought from Australia together with the eucalypts, and they seem to have facilitated the establishment of eucalypt plantations and their naturalization. The dispersion of Australian fungal propagules may be facilitating the spread of eucalypts along watercourses in semiarid regions increasing the water lost. Because ectomycorrhizal fungi are obligate symbionts, their capacity to persist after eradication of eucalypt stands, and/or to extend beyond forest plantations, would rely on the possibility to find compatible native host trees, and to outcompete the native ectomycorrhizal fungi. Here we illustrate the case of the Australasian species Laccaria fraterna, which fruits in Mediterranean shrublands of ectomycorrhizal species of Cistus (rockroses). We need to know which other Australasian fungi extend to the native ecosystems, if we are to predict environmental␣risks associated with the introduction of Australasian ectomycorrhizal fungi into the Iberian Peninsula. This revised version was published online in July 2006 with corrections to the Cover Date.     

蔷薇科植物S-RNase特异性区域分析

S-RNase在配子体型自交不亲和性反应中起关键作用,HV区段被认为是雌蕊与花粉间特异识别的关键部位。应用生物信息学方法,对蔷薇科植物的S-RNase序列分析,并对HV区段一级结构邻近区和空间邻近区作物理化学性质分析,发现HV区C端的一段氨基酸序列符合蛋白质相互作用位点的特征;HVP区也是一个多态性区段,可能参与分子识别过程。因此,蔷薇科植物中,S-RNase与花粉S基因产物的作用方式可能为S-RNase的HVC区与花粉S基因产物先非特异性结合,再以HV区和HVP区进行分子间特异识别。     

Comprehensive evaluation of multiple cropping systems on upland red soil

According to the principles and methods of ecology and system engineering, we set up an evaluation indicator system for multi-component and multiple cropping systems, evaluated the comprehensive benefits of multi-component and multiple cropping systems using grey relation clustering analysis and screened out the optimized model based on research done in the upland red soil in Jiangxi Agricultural University from 1984 to 2004. The results show that the grey relation degree of “cabbage/potato/maize — sesame” was the highest among 23 multi-component and multiple cropping systems and was clustered into the optimized system. This indicates that “cabbage/potato/maize — sesame” can bring the best social, economic and ecological benefits, increase product yield and farmers’ income and promote sustainable development of agricultural production. Therefore, it is suitable for promotion on upland red soil. The grey relation degree of “canola/Chinese milk vetch/maize/mung bean/maize” was second, which is suitable for implementation at the city outskirts. In conclusion, these two planting patterns are expected to play important roles in the reconstruction of the planting structure and optimization of the planting patterns on upland red soil. __________ Translated from Acta Ecologica Sinica, 2006, 26(8): 2532–2539 [译自: 生态学报]     

马传染性贫血病毒基因非编码区LTR嵌合克隆的构建

在已有全长感染性克隆pLGFD3-8和pD70344的基础上,根据马传贫弱毒疫苗致弱过程中不同代次毒株LTR序列的分析,在LTR U3区选取特定的酶切位点对EIAV非编码区LTR基因进行了部分替换.将替换的全基因克隆转染驴胎皮肤细胞(FDD)并以驴白细胞(DL)传代,用逆转录酶活性检测、RT-PCR方法及Real-time RT-PCR验证其感染性.结果发现,其衍生病毒感染上述两种细胞均出现明显的细胞病变;细胞培养上清可检测到RT酶活性和RT-PCR阳性.电镜下可见大量典型的EIAV颗粒.pLGFD9-12嵌合克隆衍生病毒与其父本克隆衍生病毒pLGFD3-8具有相似的复制水平,pLGFD9-12嵌合克隆衍生病毒在DL细胞上复制水平略高于FDD细胞.此结果为进一步深入研究LTR对马传染性贫血病毒复制水平和毒力的影响奠定了基础.