Improved paclitaxel accumulation in cell suspension cultures of Taxus chinensis by brassinolide

When brassinolide was added at 17 ng l^–1 to Taxus chinensis cell suspension cultures, the paclitaxel content was increased by over 100% to 580 g g^–1 dry weight. Brassinolide may therefore be a novel regulator of paclitaxel biosynthesis.     

Brefeldin A,a cytotoxin produced by Paecilomyces sp. and Aspergillus clavatus isolated from Taxus mairei and Torreya grandis

Paecilomyces sp. and Aspergillus clavatus, which were isolated from Taxus mairei and Torreya grandis from southeast China, produced toxic metabolites when grown in liquid culture. Nuclear magnetic resonance techniques, infrared spectrometry, electrospray ionization mass spectroscopy and X-ray analysis identified brefeldin A, a bioactive metabolite produced by a number of fungal species belonging to the genera Alternaria, Ascochyta, Penicillium, Curvularia, Cercospora and Phyllosticta. This is the first report of the isolation of the cytotoxin from Paecilomyces sp. and A. clavatus. The relevance of brefeldin A to the association between these fungi and their host plants is discussed.     

MS/MS profiling of taxoids from the needles of Taxus wallichiana

Ammonium cationisation has been used for taxoid profiling of partially purified methanolic extracts of needles of Taxus wallichiana growing in different regions of the Himalayas (Kashmir, Himachal Pradesh, UP Hills, Darjeeling, Sikkim and Arunachal Pradesh) by electrospray ionisation tandem mass spectrometry (MS/MS). The MS/MS spectra of the [M + NH4]+ or [M + H]+ ions gave structurally diagnostic fragment ions which revealed information about the taxane skeleton as well as the number and nature of the substituents. The rearranged 11(15-->1)-abeo-taxanes showed a characteristic elimination of the hydroxyisopropyl group with an acetoxy/benzoyloxy group from C-9. The identification of the taxoids was achieved by comparison of the MS/MS spectra with those of authentic taxoids or was based on biogenetic grounds. The results were corroborated by liquid chromatography-MS analysis. Out of the 50 taxoids identified, 21 belonged to the rearranged class. The presence of paclitaxel in the samples from four regions was confirmed: the study also revealed the occurrence of several basic taxoids in these samples. MS/MS profiling by electrospray ionisation was shown to be a fast and reliable technique for the analysis of taxoid samples.     

Increased taxane accumulation in callus cultures of Taxus cuspidata and Taxus × media by some elicitors and precursors

In Taxus cuspidata callus, vanadyl sulfate (10 mg l^–1) induced a high (146 g g^–1 dry wt) production of 10-deacetylbaccatin III in comparison to 7 g g^–1 dry wt of the control. The content of paclitaxel in this species increased from 16 g g^–1 to 74 g g^–1 dry wt when 20 mg phenylalanine l^–1 was used. In T. media, p-aminobenzoic acid induced the highest content of 10-deacetylbaccatin III (481 g g^–1 dry wt) versus 181 g g^–1 in the control. Paclitaxel increased from 89 to 139 g g^–1 dry wt after adding chitosan (20 mg l^–1) to the cultures.     

南方红豆杉组织培养及紫杉醇的产生

南方红豆杉茎段愈伤组织在不同基本培养基及激素组合的培养基上,其平均鲜重生物量具显著差异,而干重生物量无差异。适宜浓度的ＮＡＡ可以取代常用的、但致癌活的２,４－Ｄ。     

辽东山区林下人参潜在种植区域的划分

2003年我国开始的林权制度改革使农民成为森林的经营主体,在森林经营中发挥重要作用。本文在对辽宁东部山区参农调查的基础上,分析林权制度改革中参农对人参的林下种植区的自然条件选择,并根据参农的选择结果通过GIS空间分析研究人参在林下的潜在种植区分布,为林权制度改革中林业经营规划提供理论参考。结果表明:(1)参农对人参潜在种植区条件的选择符合人参生长的生理环境需求。(2)参农一般选择阴坡或半阴坡的阔叶林或针阔混交林下作为人参种植区,坡度集中在10°～25°,海拔为300～1000m,以500m处为优选区域。(3)辽宁东部山区人参潜在种植区域主要分布在新宾县、清原县、桓仁县等地。     

Involvement of nitric oxide in cerebroside-induced defense responses and taxol production in <Emphasis Type="Italic">Taxus yunnanensis</Emphasis> suspension cells

This work was to characterize the generation of nitric oxide (NO) in Taxus yunnanensis cells induced by a fungal-derived cerebroside and the signal role of NO in the elicitation of plant defense responses and taxol production. (2S,2′R,3R,3′E,4E,8E)-1-O-β-d-glucopyranosyl-2-N-(2′-hydroxy-3′-octadecenoyl)-3-hydroxy-9-methyl-4,8-sphingadienine at 10 μg/ml induced a rapid and dose-dependent NO production in the Taxus cell culture, reaching a maximum within 5 h of the treatment. The NO donor sodium nitroprusside (SNP) potentiated cerebroside-induced H₂O₂ production and cell death. Inhibition of nitric oxide synthase activity by phenylene-1,3-bis(ethane-2-isothiourea) dihydrobromide or scavenging NO by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide partially blocked the cerebroside-induced H₂O₂ production and cell death. Moreover, NO enhanced cerebroside-induced activation of phenylalanine ammonium-lyase and accumulation of taxol in cell cultures. These results are suggestive of a role for NO as a new signal component for activating the cerebroside-induced defense responses and secondary metabolism activities of plant cells. Taxol is a trademark of Bristol-Myers Squibb, Madison, NJ.     

云南红豆杉紫杉烷2α-O-苯甲酰转运酶基因的克隆及定性

通过RACE技术,克隆了云南红豆杉紫杉烷2α-O-苯甲酰转运酶基因(TyTBT),该酶催化2-去苯甲酰-7,13-二乙酰巴卡亭Ⅲ生成7,13-二乙酰巴卡亭Ⅲ,是紫杉醇合成途径中的关键酶之一.TyTBT基因cDNA全长1481 bp,含有1 320 bp的开放读码框,编码440个氨基酸的多肽,分子量为50 050 Da,等电点为6.17.氨基酸序列比对表明TyTBT同植物酰化酶家族的其它成员有较高的相似性,超过67%,同东北红豆杉和曼地亚红豆杉的紫杉烷2α-O-苯甲酰转运酶氨基酸序列的一致性和相似性达到最高,分别为95%和96%.广泛地比对分析证明这种较高的相似性在红豆杉属的其它酶家族中具有普遍性,进化树分析表明同东北红豆杉和曼地亚红豆杉的紫杉烷2α-O-苯甲酰转运酶(TBT)的相似性高于紫杉醇合成途径中的其它酰化酶.     

南方红豆杉产紫杉醇内生真菌的分离鉴定

从南方红豆杉(Taxus chinensisvar.mairei)植株分离到内生真菌63株,其中24株经鉴定分属于19个种(属).真子囊菌纲的2个属2株,半知菌纲的14个属22株.真子囊菌纲的无毛毛壳属(Achaetomiumsp.)的1株为新发现种.半知菌纲的葡萄孢属(Botrytissp.)1株和无孢菌群(Mycelia sterlia)2株的培养液,经浓缩萃取,薄层层析检测,Rf值分别为0.404、0.404、0.401,与紫杉醇对照品Rf值一致,为南方红豆杉产紫杉醇内生真菌.     

南方红豆杉和东北红豆杉中的单体化合物对乳腺癌细胞增殖的影响

本研究采用MTT法,研究南方红豆杉和东北红豆杉中的10种不同结构类型的单体化合物对乳腺癌MCF-7细胞增殖的影响。结果表明,化合物1~10(10-9~10-5mol/L)处理MCF-7细胞48和72 h后,仅化合物4在10-7、10-6和10-5mol/L浓度对MCF-7细胞增殖均有明显抑制作用,抑制率分别为29.8%、46.4%、51.8%和43.6%、61.2%、63.2%,与紫杉醇抑制细胞增殖的活性相近,且在24~72 h范围内具有时间依赖性;化合物2仅在10-5mol/L具有明显抑制细胞增殖的作用,抑制率为44.4%和49.6%。因此,10种不同结构类型的单体化合物中,仅baccatin III类化合物2、4对MCF-7细胞增殖具有较强的抑制作用,其中化合物4作用最强,活性与紫杉醇相近。