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1.
大火草根部的化学成分   总被引:15,自引:1,他引:14  
大火草(Anemone tomentosaa(Maxim.)Pei)根状茎提取物的乙酸乙酯部分对粘虫(LeucaniaseparataWalker)有较好的非选择性拒食活性。从该部分分离得到11个化合物,通过NMR、MS等波谱分析确定它们的结构分别为4,5-二甲氧基-7-甲基香豆素(1)、4-甲氧基-5-甲基-6,7-二氧亚甲基香豆素(2)、4,7-二甲氧基-5-甲基香豆素(3)、齐墩果酸(4)、齐墩果酮酸(5)、齐墩果酸-3-O-β-D-吡喃木糖甙(6)、β-谷甾醇(7)、豆甾醇(8)、胡萝卜甙(9)、豆甾醇-3-O-β-D-吡喃葡萄糖甙(10)和过氧化麦角甾醇(11)。这些化学成分均为首次从该植物中分离得到,其中1和2为新化合物。  相似文献
2.
从狭基线纹香茶菜 (Isodonlophanthoidesvar.gerardianus [Bentham]H .Hara)的乙酸乙酯部分分离得到两个木脂素类化合物 ,经 1D、2D_NMR技术鉴定 ,分别为 1_acetoxyl_2e,6e_dipiperonyl_3,7_dioxabicyclo_[3,3,0 ]_octane (1)和 1_acetoxyl_2e_piperonyl_6e_[6_methoxyl_piperonyl]_3,7_dioxabicyclo_[3,3,0 ]_octane (2 ) ,其中 2为新化合物。  相似文献
3.
A strictly anaerobic, homoacetogenic, Gram-positive, non spore-forming bacterium, designated strain SR12T(T=type strain), was isolated from an anaerobic methanogenic digestor fed with olive mill wastewater. Yeast extract was required for growth but could also be used as sole carbon and energy source. Strain SR12Tutilized a few carbohydrates (glucose, fructose and sucrose), organic compounds (lactate, crotonate, formate and betaine), alcohols (methanol), the methoxyl group of some methoxylated aromatic compounds, and H2+CO2. The end-products of carbohydrate fermentation were acetate, formate, butyrate, H2and CO2. End-products from lactate and methoxylated aromatic compounds were acetate and butyrate. Strain SR12Twas non-motile, formed aggregates, had a G+C content of 55 mol % and grew optimally at 35°C and pH 7.2 on a medium containing glucose. Phylogenetically, strain SR12Twas related toEubacterium barkeri, E. callanderi, andE. limosumwithE. barkerias the closest relative (similarity of 98%) with which it bears little phenotypic similarity or DNA homology (60%). On the basis of its phenotypic, genotypic, and phylogenetic characteristics, we propose to designate strain SR12TasEubacterium aggreganssp. nov. The type strain is SR12T(=DSM 12183).  相似文献
4.
Summary The ability ofAcetobacterium woodii andEubacterium limosum to degrade methyl esters of acetate, propionate, butyrate, and isobutyrate was examined under growing and resting-cell conditions. Both bacteria hydrolyzed the esters to the corresponding carboxylates and methanol under either condition. Methanol was further oxidized to formate under growing but not resting conditions. Unlike the metabolism of phenylmethylethers, no H2 requirement was evident for ester biotransformation. The hydrolysis of methyl carboxylates is thermodynamically favorable under standard conditions and the mixotrophic metabolism of ester/CO2 allowed for bacterial growth. These results suggest that the degradation of methyl carboxylates may be a heretofore unrecognized nutritional option for acetogenic bacteria.  相似文献
5.
Treatment of wheat leaves with heptanoyl salicylic acid (HS) and trehalose at concentrations of 0.1 and 15 g l(-1), prior to fungal inoculation, resulted in 40% and 60% protection, respectively, against powdery mildew. The total lipid composition of Blumeria graminis f.sp. tritici (Bgt) conidia, the causal agent of wheat powdery mildew, was compared when produced on wheat leaves, respectively, untreated and treated with the two elicitors, HS and trehalose. An obvious effect was observed on lipid composition (sterol and fatty acid (FA)) of Bgt conidia produced on wheat leaves treated with HS. A total of 16 FA (C12-C24 saturated and unsaturated) as well as unusual methoxylated Fatty Acids (mFA) (3-methoxydocosanoic and 3-methoxytetracosanoic acids) were detected in the conidia. Medium chain FA were predominant in HS treated conidia (64.65%) while long chain fatty acids constituted the major compounds in untreated conidia (62%). The long chain/medium chain FA ratio decreased from 1.8 in the conidia produced on untreated leaves to 0.5 in the conidia obtained from HS treated leaves. When comparing the sterol composition of Bgt conidia produced on leaves treated with HS versus conidia obtained from untreated ones, very important changes within the two major classes can be seen. In particular, 24-methylsterols, e.g., 24-methylenecholesterol and 24-methylcholesta-7,24-dien were reduced by about 82% whereas 24-ethylsterols, e.g., 24-ethylcholesterol and 24-ethylcholesta-5,22-dienol were increased by about 85%. The 24-methylsterols/24-ethylsterols ratio was reduced by ninefold in the conidia produced from HS treated leaves.  相似文献
6.
The total fatty acids (FA) composition of Blumeria graminis f.sp. tritici conidia, the causal agent of wheat powdery mildew, was analyzed as a function of their age. A total of 19 FA (C12-C24 saturated and unsaturated) and unusual methoxylated fatty acids (mFA) were detected in young, intermediate and old conidia. Two very long chain methoxylated FA were identified by GC-MS as 3-methoxydocosanoic and 3-methoxytetracosanoic acids. Medium chain FA were predominant in young conidia (75%, including 13% of mFA) while very long chain fatty acids constituted the major compounds in old conidia (74%, including 30% of mFA). We have shown for the first time that the total FA composition is strongly correlated with the age of B. graminis f.sp. tritici (Bgt) conidia.  相似文献
7.
A psychrotolerant, obligate anaerobic, acetogenic bacterium designated strain SyrA5 was isolated from black anoxic sediment of a brackish fjord. Cells were Gram-positive, non-sporeforming rods. The isolate utilized H(2)/CO(2), CO, fructose, glucose, ethanol, ethylene glycol, glycerol, pyruvate, lactate, betaine and the methyl-groups of several methoxylated benzoic derivatives such as syringate, trimethoxybenzoate and vallinate. The optimum temperature for growth was 29 degrees C, whilst slow growth occurred at 2 degrees C. The strain grew optimally with NaCl concentrations below 2.7% (w/v), but growth occurred up to 4.3% (w/v) NaCl. Growth was observed in the range from pH 5.9 to 8.5, optimum at pH 8. The G+C content was 44.1 mol%. Based upon 16S rRNA gene sequence analysis and DNA-DNA reassociation studies, the organism was classified in the genus Acetobacterium. Strain SyrA5 shared a 16S rRNA sequence similarity with A. carbinolicum of 100%, a fthfs gene (which codes for the N5,N10 tetrahydrofolate synthetase) sequence identity of 98.5-98.7% (amino acid sequence similarities were 99.4-100%) and a RNA-DNA hybridization homology of 64-68%. Despite a number of phenotypic differences between strain SyrA5 and A. carbinolicum we propose including strain SyrA5 as a subspecies of A. carbinolicum for which we propose the name Acetobacterium carbinolicum subspecies kysingense. The type strain is SyrA5 (=DSM 16427(T), ATCC BAA-990).  相似文献
8.
Alkaline nitrobenzene oxidation, ozonation and methoxyl content determinations were applied to decomposing leaf litter of Ginkgo biloba L., Cinnamomum camphora sieb., Zelkova serrata Makino and Firmiana simplex W. F. Wight, respectively, during mulching to investigate the properties and estimate changes in lignin composition and content. Since the Klason lignin residue originated from components highly resistant to degradation by acid, the methoxyl content of Klason residue was used to estimate the lignin content of leaf litter. Quantitative analysis of presumed lignin-derived fragments, by use of alkaline nitrobenzene oxidation and ozonation methods, suggested that the estimated lignin content approximates that of the real lignin content of leaves, which is greatly overestimated by the Klason procedure. The estimated lignin contents ranged from 3.9 to 10.0% while the Klason lignan residue varied from 37.1 to 46.7% in un-mulched leaf litter. The absolute amounts of the measured lignin somewhat decreased during mulching, while the structure of lignin remaining in leaf litters after mulching was considered not to be very different from its original structure.  相似文献
9.
A strictly anaerobic, homoacetogenic, gram-positive, non spore-forming bacterium, designated strain SR12(T) (T = type strain), was isolated from an anaerobic methanogenic digestor fed with olive mill wastewater. Yeast extract was required for growth but could also be used as sole carbon and energy source. Strain SR12(T) utilized a few carbohydrates (glucose, fructose and sucrose), organic compounds (lactate, crotonate, formate and betaine), alcohols (methanol), the methoxyl group of some methoxylated aromatic compounds, and H2 + CO2. The end-products of carbohydrate fermentation were acetate, formate, butyrate, H2 and CO2. End-products from lactate and methoxylated aromatic compounds were acetate and butyrate. Strain SR12(T) was non-motile, formed aggregates, had a G+C content of 55 mol % and grew optimally at 35 degrees C and pH 7.2 on a medium containing glucose. Phylogenetically, strain SR12(T) was related to Eubacterium barkeri, E. callanderi, and E. limosum with E. barkeri as the closest relative (similarity of 98%) with which it bears little phenotypic similarity or DNA homology (60%). On the basis of its phenotypic, genotypic, and phylogenetic characteristics, we propose to designate strain SR12(T) as Eubacterium aggregans sp. nov. The type strain is SR12(T) (= DSM 12183).  相似文献
10.
When the acetogen Clostridium formicoaceticum was cultivated on mixtures of aromatic compounds (e.g., 4-hydroxybenzaldehyde plus vanillate), the oxidation of aromatic aldehyde groups occurred more rapidly than did O-demethylation. Likewise, when fructose and 4-hydroxybenzaldehyde were simultaneously provided as growth substrates, fructose was utilized only after the aromatic aldehyde group was oxidized to the carboxyl level. Aromatic aldehyde oxidoreductase activity was constitutive (activities approximated 0.8 U mg–1), and when pulses of 4-hydroxybenzaldehyde were added during fructose-dependent growth, the rate at which fructose was utilized decreased until 4-hydroxybenzaldehyde was consumed. Although 4-hydroxybenzaldehyde inhibited the capacity of cells to metabolize fructose, lactate or gluconate were consumed simultaneously with 4-hydroxybenzaldehyde, and lactate or aromatic compounds lacking an aldehyde group were utilized concomitantly with fructose. These results demonstrate that (1) aromatic aldehydes can be utilized as cosubstrates and have negative effects on the homoacetogenic utilization of fructose by C. formicoaceticum, and (2) the consumption of certain substrates by this acetogen is not subject to catabolite repression by fructose. Received: 14 May 1998 / Accepted: 7 August 1998  相似文献
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