The Ordovician-Silurian boundary stratotype: consequences of its approval by the IUGS

Lespérance, Pierre J., Barnes, Christopher R., Berry, William B. N., Boucot, Arthur J. & Mu En-zhi 1987 07 15: The Ordovician-Silurian boundary stratotype: consequences of its approval by the IUGS.
The Ordovician-Silurian stratotype at Dob's Linn, Scotland is the second systemic boundary approved by the International Union of Geological Sciences (IUGS). A review of the internationally accepted criteria required of a stratotype shows that few of these are possessed by the Dob's Linn section. The strongest attribute of the section is the presence of zonal graptolites, although the boundary is recognized primarily on a single biological event (base of acuminatus Zone) for which the evolutionary relationships of the taxa are not established. In approving this boundary proposal in 1985, which received only simple majority support within the Ordovician-Silurian Boundary Working Group (OSBWG) and which fails to meet most of the accepted prerequisites for a stratotype, the International Commission on Stratigraphy (ICS) and the IUGS have established an unfortunate precedent. It follows that future systemic boundaries need not meet the accepted standards. It raises serious questions on the assessment and voting procedures of the International Commission on Stratigraphy and on the credence accorded the recommendations developed by the International Subcommission on Stratigraphic Classification of IUGS.     

山药化学成分的研究

从胡椒科植物山蒟中分得两个新木脂素类成分(Ia)和(Ⅱ),以及巴豆环氧素(Crorepoxide)(Ⅲ)和β-谷甾醇(Ⅳ)。经光谱分析及化学鉴定,(Ia)、(Ⅱ)为新结构,分别命名为山蒟素 B(hancinone)、山蒟素 C(hancinone C)。     

中国豆科植物新资料

<正>一、虫豆属 Atylosia Wight et Arn,1.白蔓草虫豆 新变种图1Atylosia scarabaeoidea(Linn)Benth ,var aryrophylla Cheng f,var ,nov     

荜拔中的新酰胺成分

从荜拔地上部分乙醇提取物中分得５个化合物,经波谱分析确定其结构分别为：（α,β,α,β）－１,３－双（３,４－二甲基苯基）－２,４－双［１－（２－羰基－５,６－二氢吡啶）－甲酰基］－环丁烷（１）。     

华南胡椒化学成分的研究

从胡椒科植物华南胡椒（Ｐｉｐｅｒ ａｕｓｔｒｏｓｉｎｅｎｓｅ Ｃ．ＤＣ．）中分离出七个成分,经光谱分析和理化常数测定,分别鉴定为Ｎ－ｉｓｏｂｕｔｙｌ－３（３＇,４＇－ｍｅｔｈｙｌｅｎｅｄｉｏｘｙ－５＇－ｍｅｔｈｏｘｙｐｈｅｎｙｌ）－２Ｅ－ｔｒｉｍｏｎｏｉｅｎａｍｉｄｅ（Ｉ）、Ｎ－ｉｓｏｂｕｔｙｌ－７（３＇,４＇－ｍｅｔｙｌｅｎｅｄｉｏｘｙｐｈｅｎｙｌ）－２Ｅ,４Ｅ－ｈｅｐｔａｄｉｅｎａｍｉｄｅ（Ⅱ     

中国蜡梅属植物过氧化物同工酶的研究

采用聚丙烯酰胺凝胶电泳系统,进行了蜡梅属8种植物过氧化物同工酶的研究。结果发现：该属8种植物的酶谱差异显著,每个种均有其特征酶谱。根据其种的酶谱酶带数目、Rf、宽度及其活性强弱的不同,可将各个种加以区别,但不支持保康蜡梅和突托蜡梅作为独立种的存在,也不支持蜡梅属分为蜡梅组和新蜡梅组的观点。同时,采用排序方法对蜡梅属8种植物酶谱的相似程度进行排序结果发现：与该属8种植物酶谱分类相吻合,并从分子水平上论证了它们的亲缘关系,即保康蜡梅为蜡梅的种内变异,以作蜡梅栽培品种处理;突托蜡梅作为浙江蜡梅的变种为佳,从而为蜡梅属植物种群的合理划分,提出了新的依据和手段。     

莎草属果皮微形态特征及其分类学上的意义

首次报道了在立体显微镜及扫描电子显微镜下对莎草属(Cyperus Linn.)14种、2变种植物果皮微形态特征的观察结果。根据纹饰特点的不同,可分为三种类型:(1)网——瘤状复合纹饰;(2)网状纹饰;(3)疣状纹饰。莎草属植物在果皮微形态特征上存在的种间差异可为种的划分提供依据,并为探讨该属的系统演化提供有价值的资料。     

缬草挥发油化学成分的研究

采用气相色谱-质谱联用仪对产于太白县的缬草根和茎叶中的挥发油成分分别进行分析,从根中鉴定出45种成分,以茎叶中鉴定出67种成分,并用GC测定了每一成分在该挥发油中的含量。     

Piper longum Constituents Induce PANC-1 Human Pancreatic Cancer Cell Death under Nutrition Starvation

Pancreatic cancer is a highly aggressive form of cancer with a poor prognosis, partly due to ‘austerity’, a phenomenon of tolerance to nutrient deprivation and survival in its hypovascular tumor microenvironment. Anti-austerity agents which preferentially diminish the survival of cancer cells under nutrition starvation is regarded as new generation anti-cancer agents. This study investigated the potential of Piper longum constituents as anti-austerity agents. The ethanolic extract of Piper longum was found to have preferential cytotoxicity towards PANC-1 human pancreatic cancer cells in a nutrient-deprived medium (NDM). Further investigation led to the identification of pipernonaline ( 3 ) as the lead compound with the strongest anti-austerity activity, inducing cell death and inhibiting migration in a normal nutrient medium, as well as strongly inhibiting the Akt/mTOR/autophagy pathway. Therefore, pipernonaline ( 3 ) holds promise as a novel antiausterity agent for the treatment of pancreatic cancer.     

Chemical Profile and Biological Activities of Fungal Strains Isolated from Piper nigrum Roots: Experimental and Computational Approaches

The current report describes the chemical investigation and biological activity of extracts produced by three fungal strains Fusarium oxysporum, Penicillium simplicissimum, and Fusarium proliferatum isolated from the roots of Piper nigrum L. growing in Vietnam. These fungi were namely determined by morphological and DNA analyses. GC/MS identification revealed that the EtOAc extracts of these fungi were associated with the presence of saturated and unsaturated fatty acids. These EtOAc extracts showed cytotoxicity towards cancer cell lines HepG2, inhibited various microbacterial organisms, especially fungus Aspergillus niger and yeast Candida albicans (the MIC values of 50–100 μg/mL). In α-glucosidase inhibitory assay, they induced the IC₅₀ values of 1.00-2.53 μg/mL were better than positive control acarbose (169.80 μg/mL). The EtOAc extract of F. oxysporum also showed strong anti-inflammatory activity against NO production and PGE-2 level. Four major compounds linoleic acid (37.346 %), oleic acid (27.520 %), palmitic acid (25.547 %), and stearic acid (7.030 %) from the EtOAc extract of F. oxysporum were selective in molecular docking study, by which linoleic and oleic acids showed higher binding affinity towards α-glucosidase than palmitic and stearic acids. In subsequent docking assay with inducible nitric oxide synthase (iNOS), palmitic acid, oleic acid and linoleic acid could be moderate inhibitors.