Relationships between inhibitory activity against a cancer cell line panel, profiles of plants collected, and compound classes isolated in an anticancer drug discovery project

In an attempt to determine the relationships between the plant profiles (country of collection, taxonomy, plant part) and the compound classes isolated with cytotoxic activity against a panel of human tumor cell lines, the data compiled from a 15-year anticancer drug-discovery project were subjected to an analysis of variance (ANOVA). The results indicate significant trends in cytotoxic activity relative to collection location, taxonomy, plant part, and compound classes isolated. Plant collections were made in tropical forests in six countries, with collections from Ecuador resulting in higher activity than those from Indonesia and Peru. Interestingly, collections from Florida were not statistically different than those from the countries with higher biodiversity. One hundred and forty-five families were represented in the collections, with the Clusiaceae, Elaeocarpaceae, Meliaceae, and Rubiaceae having low ED50 (half maximal effective dose) values. Especially active genera included Aglaia, Casearia, Exostema, Mallotus, and Trichosanthes. Roots and below-ground plant materials were significantly more active than above-ground materials. Cucurbitacins, flavaglines, anthraquinones, fatty acids, tropane alkaloids, lignans, and sesquiterpenoids were significantly more active than xanthones and oligorhamnosides. The results from this study should serve as a guide for future plant collection endeavors for anticancer drug discovery.     

Abscisic acid plays an important role in the regulation of strawberry fruit ripening

The plant hormone abscisic acid (ABA) has been suggested to play a role in fruit development, but supporting genetic evidence has been lacking. Here, we report that ABA promotes strawberry (Fragaria ananassa) fruit ripening. Using a newly established Tobacco rattle virus-induced gene silencing technique in strawberry fruit, the expression of a 9-cis-epoxycarotenoid dioxygenase gene (FaNCED1), which is key to ABA biosynthesis, was down-regulated, resulting in a significant decrease in ABA levels and uncolored fruits. Interestingly, a similar uncolored phenotype was observed in the transgenic RNA interference (RNAi) fruits, in which the expression of a putative ABA receptor gene encoding the magnesium chelatase H subunit (FaCHLH/ABAR) was down-regulated by virus-induced gene silencing. More importantly, the uncolored phenotype of the FaNCED1-down-regulated RNAi fruits could be rescued by exogenous ABA, but the ABA treatment could not reverse the uncolored phenotype of the FaCHLH/ABAR-down-regulated RNAi fruits. We observed that down-regulation of the FaCHLH/ABAR gene in the RNAi fruit altered both ABA levels and sugar content as well as a set of ABA- and/or sugar-responsive genes. Additionally, we showed that exogenous sugars, particularly sucrose, can significantly promote ripening while stimulating ABA accumulation. These data provide evidence that ABA is a signal molecule that promotes strawberry ripening and that the putative ABA receptor, FaCHLH/ABAR, is a positive regulator of ripening in response to ABA.     

高血压大鼠心脏和血管MAPK磷酸酶-1表达的改变及对平滑肌细胞增殖的影响

目的和方法：比较自发性高血压大鼠（SHR）和对照（WKY）大鼠心脏和主动脉丝裂素活化蛋白激酶磷酸酶－1（MKP－1）及细胞外信号调节激酶（ERK－1）的表达,并观察用磷酸钙共沉淀方法转染MKP－1基因对血管紧张素Ⅱ（Ang Ⅱ）刺激平滑肌细胞（VSMC）^3H－胸腺叫啶（^3H-TdR)掺入的影响,以探讨MKP－1在细胞增殖中的调节作用。结果：①与WKY大鼠相比,SHR心脏和主动脉MKP－1呈低表达,分别降低53％和45％（P均＜0．01）;而SHR心脏和主动脉ERK－1呈明显高表达（P均＜0．01）,SHR心脏和主动脉ERK－1与MKP－1蛋白比值明显高于WKY。②AngⅡ 10^-7mol/L刺激VSMC增殖较对照组增加257％（P＜0．01）,转染野生型MKP－1基因细胞可使AngⅡ刺激的^3H-TdR掺入较未转染的细胞降低63％（P＜0．05）,转染突变型MKP－1基因和转染空载体的VSMC对AngⅡ的刺激与单纯AngⅡ组相比无明显抑制作用（P＞0．05）。结论：SHR心血管组织中促增殖肥大的ERK－1表达较其失活的MKP－1占优势,并且MKP－1可显著抑制AngⅡ的VSMC增殖。     

Identification and hexavalent chromium reduction characteristics of <Emphasis Type="Italic">Pannonibacter phragmitetus</Emphasis>

A hexavalent chromium [Cr(VI)] reducing bacterial strain was isolated from chromium-containing slag. It was identified as Pannonibacter phragmitetus based on physiological, biochemical characteristics and 16S rRNA gene sequence analysis. This bacterium displayed great Cr(VI) reduction capability. The Cr(VI) could be completely removed in 24 h under anaerobic condition when the initial concentration was 1,917 mg L⁻¹, with the maximum reduction rate of 562.8 mg L⁻¹ h⁻¹. The Cr(VI) reduction rate increased with the increase of Cr(VI) concentration. P. phragmitetus was able to use many carbon sources such as lactose, fructose, glucose, pyruvate, citrate, formate, lactate, NADPH and NADH as electron donors, among which the lactate had the greatest power to promote the reduction process. Zn²⁺, Cd²⁺ and Ni²⁺ inhibited, while Cu²⁺, Pb²⁺, Mn²⁺ and Co²⁺ stimulated the reduction. The optimum pH and temperature for reduction were 9.0 and 30 °C, respectively. The results indicated that this strain had great potential for application in the bioremediation of chromate-polluted soil and water systems.     

抗呼吸道合胞病毒(RSV)单克隆抗体的制备及其对RSV病毒株抗原性的分析

用呼吸道合胞病毒R6(武汉地方株)活毒滴鼻加用戍二醛固定的病毒感染的Hela细胞免疫BALB/C鼠,取脾细胞与小鼠骨髓瘤SP_2/0细胞融合,培育出分泌抗呼吸道合胞病毒单克隆抗体的杂交瘤细胞13株,这些细胞的染色体数为94至104条,其分泌的抗体分别属于鼠IgC_1、IgG_(2a)、IgG_(2b)亚类。腹水荧光抗体滴度为1:10000～1:100000。其中五株单抗有中和病毒作用,尤其是两株中和放价达1:128。应用免疫转印法证实了这些单抗分别能识别RSV6种主要结构蛋白,用7株识别不同病毒结构蛋白的单抗对12株合胞病毒进行抗原性分析,可将这些病毒区分为二个血清型,即A亚型和B亚型。     

血红细胞超氧化物歧化酶(SOD)制备工艺的研究初报

本文报告了本实验室设计的由血红细胞自溶液60℃热变性, 乙醇——氯仿法除血红蛋白,旋转蒸发法减压浓缩抽去氯仿、乙醇,硫酸铵分级盐析法沉降SOD,Sepbadex G-75层析提纯SOD等步骤构成的一条成本低、设计合理、简便实用的分离纯化SOD的工艺路线。