Cytotoxic steroidal saponins from Trillium kamtschaticum

Eight new steroidal saponins, trillikamtosides K–R (1–8), along with three known analogues, were isolated from the whole plants of Trillium kamtschaticum. Their structures were unambiguously established by interpretation of spectroscopic data (MS and NMR) and chemical methods. Compound 1 had a rare aglycone featuring a skeleton of 16-oxaandrost-5-en-3-ol-17-one, which was reported for the first time. The isolated saponins were tested for cytotoxicities against HCT116 cells, and trillikamtoside R (8) was found to show the most cytotoxic effect with an IC₅₀ value of 4.92 μM.     

黔中喀斯特木本植物功能性状变异及其适应策略

性状变异反映了植物的生活史对策。该研究以贵州普定县天龙山10种木本植物为对象, 通过分析枝叶和根系9个功能性状的种间与种内变异, 揭示植物对喀斯特生境的适应策略。结果表明: (1) 9个性状变异程度不同, 细根组织密度的种间和种内变异系数最大, 分别达96.47%和51.44%, 小枝干物质含量的种间与种内变异最小, 分别为11.67%和6.83%。(2)种间水平的细根组织密度在不同物种中没有显著的差异, 比根长、叶厚度、叶面积、比叶面积、叶干物质含量、叶组织密度、小枝干物质含量和小枝组织密度均表现出显著的差异。在种内, 比叶面积差异显著, 其他性状差异不显著。(3)绝大多数叶和枝性状间显著相关, 比根长与比叶面积显著负相关, 其他根系性状与枝叶性状相关性不显著。总之, 与同纬度非喀斯特地区植物相比, 普定喀斯特地区植物具有较小的叶面积和比根长度, 较大的叶干物质含量、叶组织密度等一系列有利于减小蒸腾和储存养分的功能性状组合, 这可能是其适应干旱贫瘠的喀斯特环境的主要生态策略。     

Evolutionary history of a desert perennial Arnebia szechenyi (Boraginaceae): Intraspecific divergence,regional expansion and asymmetric gene flow

The complex interactions of historical, geological and climatic events on plant evolution have been an important research focus for many years. However, the role of desert formation and expansion in shaping the genetic structures and demographic histories of plants occurring in arid areas has not been well explored. In the present study, we investigated the phylogeography of Arnebia szechenyi, a desert herb showing a near-circular distribution surrounding the Tengger Desert in Northwest China. We measured genetic diversity of populations using three maternally inherited chloroplast DNA (cpDNA) fragments and seven bi-paternally inherited nuclear DNA (nDNA) loci that were sequenced from individuals collected from 16 natural populations across its range and modelled current and historical potential habitats of the species. Our data indicated a considerably high level of genetic variation within A. szechenyi and noteworthy asymmetry in historical migration from the east to the west. Moreover, two nuclear genetic groups of populations were revealed, corresponding to the two geographic regions separated by the Tengger Desert. However, analysis of cpDNA data did not show significant geographic structure. The most plausible explanation for the discrepancy between our findings based on cpDNA and nDNA data is that A. szechenyi populations experienced long periods of geographic isolation followed by range expansion, which would have promoted generalized recombination of the nuclear genome. Our findings further highlight the important role that the Tengger Desert, together with the Helan Mountains, has played in the evolution of desert plants and the preservation of biodiversity in arid Northwest China.     

A Preliminary Study on Alien Invasive Plants in Jiangsu,China

From 1985 to 2013, there were only 9 literatures reports on alien invasive plants in Jiangsu, less than 025% of total 3665 similar reports during the same period in China, and it was much disproportionate with the development level of social, economic, cultural and other aspects of the province. Through field investigation, literature review and specimen inspection, the preliminary statistics, analysis and discussion of 47 families 128 genera and 209 species of alien invasive plants in Jiangsu have been made, including their composition, origin, and the life form. All alien invasive plants were ranked into 5 grades according to the damage to ecosystem and economy: twenty two malignant invasive species; forty one serious invasive species; thirty two local invasive species; fifty one general invasive species; a left 63 species with unknown damage wait for further observation. The characteristics of alien invasive plants in Jiangsu have been discussed, and the proposals of suggestion have been made.     

过表达微小RNA miR-125b抑制肝癌细胞上皮-间质转换及促进细胞凋亡

微小RNA-125b（miR-125b）在许多恶性肿瘤的增殖、分化和凋亡等过程中具有很重要的作用,但miR-125b是否涉及肝癌的上皮 间质转换过程（EMT）还有待进一步研究。本研究通过构建过表达miR-125b的肝癌稳转细胞株,初步检测miR-125b对于肝癌的EMT过程和相关的TGF-β信号通路的影响,以及对于肝癌细胞凋亡的影响。以慢病毒载体pHRS-1cla EGFP 构建过表达miR-125b的载体质粒(pHRS-1cla-miR125b-CMV-EGFP),并对上述载体进行NheⅠ、XbaⅠ双酶切和测序鉴定,鉴定正确后,在293T细胞中进行慢病毒包装,浓缩病毒后,对MHCC97-H进行慢病毒感染并采用流式分选GFP阳性的细胞。实时定量PCR检测表明肝癌细胞稳转株MHCC97-H-PHRS-miR-125b-EGFP的miR-125b表达量是空载体转染组的6倍。Western印迹检测发现,与空载体对照组相比,MHCC97-H-PHRS-miR-125b-EGFP细胞中间质细胞标志α-SMA表达显著下调,上皮细胞标志E-cadherin表达显著上调,同样的,用Western印迹检测也发现MHCC97-H-PHRS-miR-125b-EGFP细胞中TGF-β信号通路关键下游分子Smad2和Smad4的表达显著下调,细胞凋亡检测结果表明,与对照组相比,过表达miR-125b的稳转株凋亡率增加到19.66%,加入TGF-β1后,过表达miR-125b的稳转株凋亡率进一步增加到74.7%。同样的,在体内治疗实验中,我们采用商品化的体内核酸转染试剂,在皮下肿瘤组织中过表达miR-125b mimics,结果表明miR-125b的过表达与肿瘤组织的凋亡成正相关性（r=0.83463,P < 0.01）,且免疫组化结果也表明,miR-125b过表达后,E-cadherin表达显著上调,α-SMA及Smad2和Smad4的表达显著下调。上述结果表明,我们成功构建了过表达miR-125b的肝癌细胞稳转株,并成功建立了肿瘤组织中过表达miR-125b mimics的动物模型,在体内外均观察到过表达miR-125b后对肝癌细胞EMT过程的抑制作用和对细胞凋亡的促进作用。相关研究结果加深了我们对miR-125b在肝癌中抑制肝癌发展作用机制的理解,及其作为潜在的治疗肝癌的新靶点的重要性。     

新疆南部棉区杏树对棉田主要害虫和自然天敌的影响

2008—2011年在新疆莎车县调查研究了杏树对棉田主要害虫及自然天敌种群发生的影响。研究表明杏棉间作田主要害虫及天敌种类与棉单作田一致。杏树间作种植模式对棉田牧草盲蝽Lygus pratensis、棉蓟马Thripstabaci和棉长管蚜Acyrthosiphon gossyfii的种群发生有一定影响,不利于其在田间发生;对棉蚜Aphis gossyfii、棉叶螨Tetrangchus urticae影响不大。棉田瓢虫和食虫蝽天敌受间作和棉蚜发生量的双重影响。间作有利于蜘蛛数量的增加。     

科尔沁沙地沙丘迎风坡面干沙层的空间分布

对科尔沁沙地西部地区流动沙丘和固定沙丘的迎风坡表层干沙层厚度进行观测,分析了沙丘坡面干沙层的空间分布特点.结果表明:研究区沙丘迎风坡表层干沙层厚度主要在5 ～15 cm,92.0％的流动沙丘区域和98.6％的固定沙丘区域的干沙层厚度分布在此范围内;固沙植物影响沙丘表层干沙层的厚度变化和空间分布.流动沙丘表层干沙层厚度表现出明显的空间差异性:迎风坡上部西侧区域干沙层厚度较大,下部东侧区域相对较薄,其平均厚度为(9.58±3.95) cm,干沙层厚度在0～ 40 cm范围内变化,变异系数为41％,干沙层空间分布的变异函数表现为球状模型,具有中等的空间相关性;固定沙丘的干沙层厚度表现为明显的均一性,空间差异性不明显,其平均厚度为(10.91±1.70) cm,干沙层厚度变化范围在0～20 cm,变异系数仅16％.     

浙江省外来入侵植物研究

基于国内外文献资料、标本信息和野外调查,初步整理了浙江省外来入侵植物的种类组成、生活型、原产地、危害程度和入侵途径。结果表明,浙江省现有外来人侵植物46科106属166种,种数最多的是菊科、豆科和禾本科。根据原产地分析,来源于南美洲的物种最多,约占总数的32．16％,其次为北美洲,约占总数的25．63％,欧洲排第三位,约占总数的19．59％;已产生严重危害的有23种,中等危害的60种,危害较轻的83种。还有一些物种虽然没有在表里列出,但它们具有潜在的危害,必须密切关注。同时,与之前的研究相比,我们去除了一些已报道为人侵的物种,又增加了一些新的入侵种。在此基础上,对浙江省外来入侵植物的生活型、来源及危害进行了分析,并与以往的研究进行了比较,提出了针对性的管理建议。     

Nitrogen deposition promotes phosphorus uptake of plants in a semi-arid temperate grassland

Plant and Soil - Nitrogen (N) deposition greatly influences ecosystem processes through the alteration of plant nutrition; however, there is limited understanding about the effects of phosphorus...     

Biocatalytic synthesis and in vitro release of biodegradable linear polyesters with pendant ketoprofen

Enzyme-catalyzed polycondensation for the synthesis of polyester prodrugs of ketoprofen was reported. Lipase acrylic resin from Candida antarctica (CAL-B) was used to synthesize the linear polyesters with pendent ketoprofen groups based on ketoprofen glycerol ester, poly(ethylene glycol), and divinyl sebacate. The products were characterized by GPC and (1)H NMR. The results indicated that the molecular weight and yields of the polyesters depend on experimental conditions such as temperature and feed ratio. The in vitro study showed that the drug release from the polyester was slow under physiological conditions, which indicated that the polyester could be a promising prodrug with extended pharmacological effects by delayed release of ketoprofen.