Allium discoloration: the precursor and formation of the red pigment in giant onion (Allium giganteum Regel) and some other subgenus Melanocrommyum species

The precursor of the orange-red pigment formed upon wounding the bulbs of Allium giganteum (Allium subg. Melanocrommyum) was isolated and shown to be S-(2-pyrrolyl)cysteine S-oxide. In addition, two other pyrrolylsulfinyl derivatives were found in an extract from the bulbs, namely, 3-(2-pyrrolylsulfinyl)lactic acid and S-(3-pyrrolyl)cysteine S-oxide. Contrary to a previous report, the latter compound was shown not to serve as the precursor of the pigment, being in fact only an artifact formed during isolation. The formation of pyrrolyl-containing compounds following disruption of A. giganteum bulbs was studied by a combination of LC-MS, LC-NMR and DART-MS. It was found that S-(2-pyrrolyl)cysteine S-oxide is cleaved by a C-S lyase (alliinase) to yield 2-pyrrolesulfenic acid. Two molecules of the latter compound give rise to highly reactive S-(2-pyrrolyl) 2-pyrrolethiosulfinate which in turn converts into red 2,2'-epidithio-3,3'-dipyrrole (dipyrrolo[2,3-d:2',3'-e]-1,2-dithiin). Several other pyrrolyl-containing compounds were detected in A. giganteum for the first time, including S-methyl 2-pyrrolethiosulfinate, S-(2-pyrrolyl) methanethiosulfinate, di(2-pyrrolyl) disulfide, and S-(2-pyrrolyl) 2-pyrrolethiosulfonate. It can be concluded that the formation of the orange-red pigment in Allium subg. Melanocrommyum species, despite sharing several analogous features, is of a different nature than the pink discoloration of onion (A. cepa).     

Isolation and identification of organosulfur compounds oxidizing canine erythrocytes from garlic (Allium sativum)

Five compounds oxidizing canine erythrocytes were isolated from an aqueous ethanol garlic extract by silica gel column chromatography and preparative thin-layer chromatography. On the basis of nuclear magnetic resonance, infrared spectroscopy, and mass spectrometry, they were identified as three known compounds: bis-2-propenyl trisulfide (1), bis-2-propenyl tetrasulfide (2), and bis-2-propenyl pentasulfide (3) as well as two novel compounds, bis-2-propenyl thiosulfonate (4) and trans-sulfuric acid allyl ester 3-allylsulfanyl-allyl ester (5). A mixture of compounds 1-3 and compounds 4 and 5 induced methemoglobin formation in canine erythrocyte suspension in vitro resulting in the oxidation of canine erythrocytes. These groups of characteristic organosulfur compounds contained in garlic probably contribute to oxidations in blood. The constituents of garlic have the potential to oxidize erythrocytes and hemoglobin, suggesting that foods containing quantities of garlic should be avoided for feeding dogs.     

Isolation and identification of phase II enzyme-inducing agents from nonpolar extracts of green onion (Allium spp.)

The objective of the study was to isolate and identify potential cancer preventive constituents from green onion based on the ability to induce quinone reductase (QR, a representative phase II enzyme) in murine hepatoma cells (Hepa 1c1c7). Crude nonpolar solvent extracts were prepared from freeze-dried green onion by sequential refluxing with hexane and then ethyl acetate, followed by liquid-liquid extraction. Active fractions were subjected to the Hepa 1c1c7 bioassay-guided steps of flash chromatography, thin layer chromatography (TLC), and high-pressure preparative liquid chromatography (HPLC) to afford pure isolates capable of inducing QR. Multiple fractions were active in inducing QR. Five pure compounds were isolated from active fractions and identified using spectroscopic methods; these were p-hydroxyphenethyl trans-ferulate (1), 5,6-dimethyl-2-pyridinecarboxylic acid (2), ferulic acid (3), 1-(6-hydroxy-[3]pyridyl)-propan-1-one (4), and N-trans-feruloyl 3-O-methyldopamine (5). p-Hydroxyphenethyl trans-ferulate (1) doubled QR specific activity in Hepa 1c1c7 cells at a level of 2.1 microg/mL (6.6 microM).     

Isolation and characterization of a bioactive mannose-binding protein from the Chinese chive Allium tuberosum

A mannose-binding protein was isolated from two different cultivars of the Chinese chive Allium tuberosum by extraction with 0.2 M NaCl, ammonium sulfate precipitation, and affinity chromatography on mannose agarose and fetuin agarose. It exhibited hemagglutinating activity toward rabbit erythrocytes. The lectin (agglutinin) was adsorbed on the mannose-agarose column, but not on the fetuin-agarose column. This A. tuberosum lectin (ATL) is unglycosylated, and not sialic acid binding. Lectins isolated from the two cultivars exhibited the same molecular mass of 25 kDa on gel filtration (Superose 12) and 12.5 kDa on SDS-polyacrylamide gel electrophoresis, indicating that they might be a dimeric protein composed of two identical subunits. The N-terminal amino acid sequence analysis of the lectin of various cultivars of A. tuberosum revealed that they were identical and showed 50%, or more, homology to the lectins from Galanthus nivalis (family Amaryllidaceae), Narcissus tazetta (family Amaryllidaceae), and Aloe arborescenes (family Liliaceae).     

Isolation and identification of hexaketides from a pigmented Monosporascus cannonballus isolate

Monosporascus cannonballus causes severe production losses to muskmelon and watermelon in the United States and other countries. Wild types of the fungus produce no pigments when grown on potato dextrose agar (PDA). After long-term storage on soil/oat hull mix, however, some isolates of the fungus produce yellow to brown pigments and no perithecia when grown on PDA. Five colored metabolites from pigmented cultures of M. cannonballus isolate TX923038 have now been identified. Two of these, monosporascone and dehydroxyarthrinone, have been isolated from other fungi, and three, demethylcerdarin, monosporascol A and azamonosporascone, have not previously been reported. The (1)H NMR and (13)C NMR of all five compounds are reported.     

牡丹花红色素理化性质研究

目前牡丹主要是用于观赏,其综合加工技术没有突破。为了为牡丹花保鲜、护色和色素加工提供理论支持,该文对从牡丹红色品种洛阳红中提取的牡丹红色素进行理化性质研究。结果显示:牡丹红色素水溶性好,颜色随pH值变化而变化。pH值小于3时比较稳定,最大吸收波长为526.5 nm。在酸性条件下该色素对光、热有很好的稳定性;耐氧化性和还原性较差;Zn²⁺、Mg²⁺、Fe²⁺、K⁺、Cu²⁺、Ca²⁺离子对牡丹花红色素的稳定性影响不大,但Sn²⁺、Fe³⁺离子可使色素溶液变色,稳定性差。     

一株红壤花生根际溶磷真菌的分离、鉴定及溶磷能力的研究

为提高磷素利用率,从花生根际土壤样品中筛选到一株溶磷能力强的菌株B1-A,结合菌落形态特征和ITS rDNA序列分析将其鉴定为黑曲霉(Aspergillus niger)。菌株B1-A的不同接种量(1%,3%,5%)在两种难溶性磷酸盐(FePO4,AlPO4)培养液的溶磷量和pH随时间动态变化表明溶磷量均与pH呈显著负相关,B1-A的溶磷量与接种量、培养时间、磷矿粉浓度有关,实验结果表明菌株B1-A在接种量为3%～5%、培养时间168 h、云南磷矿粉浓度为3 g L-1、江西磷矿粉浓度为5 g L-1时溶磷效果较好。菌株B1-A对磷酸三钙、磷酸铝、磷酸铁、磷矿粉有较强的溶解能力,最高溶磷量分别为418.7、942.3、242.2、177.4 mg L-1,有望为开发高效红壤微生物磷肥提供种质资源。     

Isolation and identification of iron-reducing bacteria from gley soils

Seventy-one facultative anaerobic bacteria, capable of reducing iron oxide in pure culture, were isolated from three differently gleyed subsoils. The bacteria were picked at random from poured plates (10⁻⁵ and 10⁻⁶) inoculated with serially diluted soil samples. An attempt was made to identify these strains by morphological and biochemical tests. Among these 71 iron-reducing bacteria, all except three were capable of reducing nitrate to nitrite and 35 reduced nitrite further into gaseous compounds (denitrification), but only one strain (Bacillus subtilis) produced H₂S. Based upon their physiological and morphological properties, 38 strains were allotted to the genus Pseudomonas, 31 sporeformers to the genus Bacillus and two were regarded to be coryneform (Arthrobacter?) bacteria. Species identified were Ps. denitrificans (23), ps. stutzeri (8) ps. fluorescens-putida (5), Bacillus cereus (6), B. cereus var. mycoides (14) and Bacillus subtilis (9). Two spore-forming bacilli, two non-pigmented pseudomonads and two coryneform type of bacteria could not be identified. The significance of the enzyme nitrate reductase (nitratase) of these bacteria for anaerobic respiration and as a mechanism of iron reduction is discussed.     

蛇口腔炎病原菌的分离与鉴定

从眼镜蛇、榕蛇、水律蛇和广蛇的口腔溃烂处以及肝、肺分离到两种细菌，经致病性试验，证实这两种细菌都具有致病性。根据形态、生长特征和生化特性，8株被鉴定为变形菌属的普通变形杆菌，6株被定为摩根氏菌属的摩根氏菌。药敏试验结果表明，普通变形杆菌和摩根氏菌均对菌必治、呋喃妥因、头孢他啶、环丙沙星敏感。采取以菌必治为主，配合环丙沙星和头孢他啶的治疗方案，总的治愈率达70．6％。     

Isolation and identification of oxamyl-degrading bacteria from UK agricultural soils

Bacteria capable of utilising oxamyl as the sole carbon source were isolated from seven different agricultural soils that had previously demonstrated enhanced oxamyl degradation in a soil incubation study. Partial sequencing and alignment of the 16S rRNA gene showed little diversity amongst isolates, with 26 of the 27 isolates demonstrating similarity to the genus Aminobacter. The most common species isolated was Aminobacter aminovorans, while a number of the isolates demonstrated an equal degree of similarity to the species Aminobacter niigataensis and Chelatobacter heintzii. One isolate was identified as Mesorhizobium sp. This is the first time that organisms involved in the degradation of oxamyl have been isolated and identified.     

Antispasmodic saponins from bulbs of red onion, Allium cepa L. var. Tropea

A phytochemical analysis of the polar extract from the red bulbs of Allium cepa L. var. Tropea, typical of Calabria, a southern region of Italy, was performed extensively for the first time, leading to the isolation of four new furostanol saponins, named tropeoside A1/A2 (1a/1b) and tropeoside B1/B2 (3a/3b), along with the respective 22-O-methyl derivatives (2a/2b and 4a/4b), almost certainly extraction artifacts. High concentrations of ascalonicoside A1/A2 (5a/5b) and ascalonicoside B (6), previously isolated from Allium ascalonicum Hort., were also found. This is the first report of furostanol saponins in this A. cepa variety. The chemical structures of the new compounds were established through a combination of extensive nuclear magnetic resonance, mass spectrometry and chemical analyses. High concentrations of quercetin, quercetin 4(I)-glucoside, taxifolin, taxifolin 7-glucoside, and phenylalanine were also isolated. The new saponins were found to possess antispasmodic activity in the guinea pig isolated ileum; such an effect might contribute to explaining the traditional use of onion in the treatment of disturbances of the gastrointestinal tract.     

Isolation and identification of antifungal and antialgal alkaloids from Haplophyllum sieversii

Bioassay-guided fractionation of the hexane/ethyl acetate/water (H/EtOAc/H2O) crude extract of the aerial parts of Haplophyllum sieversii was performed because of preliminary screening data that indicated the presence of growth inhibitory components against Colletotrichum fragariae, Colletotrichum gloeosporioides, and Colletotrichum acutatum. Fractionation was directed using bioautographical methods resulting in the isolation of the bioactive alkaloids flindersine, anhydroevoxine, haplamine, and a lignan eudesmin. These four compounds were evaluated for activity against C. fragariae, C. gloeosporioides, C. acutatum, Botrytis cinerea, Fusarium oxysporum, and Phomopsis obscurans in a dose-response growth-inhibitory bioassay at 50.0, 100.0, and 150.0 microM. Of the four compounds tested, flindersine demonstrated the highest level of antifungal activity. Additionally, flindersine, eudesmin, and haplamine were screened against the freshwater phytoplanktons Oscillatoria perornata, Oscillatoria agardhii, Selenastrum capricornutum, and Pseudanabaena sp. (strain LW397). Haplamine demonstrated selective inhibition against the odor-producing cyanobacterium O. perornata compared to the activity against the green alga S. capricornutum, with lowest observed effect concentration values of 1.0 and 10.0 microM, respectively.     

Isolation, identification, and characterization of an aluminum-tolerant bacterium Burkholderia sp. SB1 from an acidic red soil

Aluminum (Al) toxicity usually occurs in acidic soils worldwide, which is detrimental to the growth of organisms. An Al-tolerant bacterium, SB1, was isolated from an acidic red soil of Chingkang Mountain, located in Jiangxi Province of China. Polyphasic analysis, including a 16S rDNA phylogenetic tree as well as morphological and physicochemical properties, revealed that the isolate was a gramnegative, rod-shaped bacterium, which was recognized as Burkholderia sp. SB1 and had extreme acidity tolerance (pH 2.2) and excellent Al resistance (270 mg L^-1 Al³⁺). It could remove Al by up to 97.7% at a concentration of 54 mg L^-1 Al³⁺. SB1 behavior under different temperatures and antibiotics was also examined. SB1 preferred moderate temperature conditions, ranging from 25 to 37℃, and exhibited notable resistance to multiple antibiotics (including ampicillin, streptomycin, and tetracycline), except for being sensitive to chloramphenicol. Therefore, as the first reported bacterium to possess favorable Al resistance and excellent Al removal, Burkholderia sp. SB1 can potentially be used as an agent for bioremediation of Al-contaminated acidic red soils.     

广西斜纹夜蛾核型多角体病毒的分离鉴定

从广西部分地区采集到自然罹病死亡的疑似具有病毒症状的斜纹夜蛾幼虫，对其进行病毒的分离鉴定。用研磨病虫尸体得到的浆液，经分离纯化后感染连续人工饲养至第三代的健康斜纹夜蛾三龄幼虫，部分样品能诱发病毒病症状。经差速离心的提纯物，在相差显微镜下观察到外形不规则的颗粒，进一步在电镜下观察到菱形、五边型、六边形、近似圆形等形状的多角体。用依据SpltNFV DNA的egt基因保守序列设计的引物，对多角体中提取的DNA进行PCR扩增，得到了与预期一致的380bp片段。经测序分析，该PCR片段与Splt NPV egt基因在核苷酸水平上的同源性为99．4％，演绎的氨基酸水平上的同源性为100％。进一步对采自广西16个地域的疑似具有病毒症状的200份斜纹夜蛾幼虫样本进行PCR扩增，其中6个地域的62份样本呈PCR阳性，这表明，广西斜纹夜蛾自然种群中存在着SpltNPV的流行。     

Isolation and identification of boron-accumulating bacteria from contaminated soils and active sludge

High levels of boron are toxic to living organisms. The removal of boron from contaminated water is an important way of dealing with this environmental problem. For this purpose, we screened for bacteria that can absorb high levels of toxic boron from the environment. A range of boron-accumulating bacteria was isolated from boron-contaminated soil in Turkey, from uncontaminated soil in Tokyo, Japan, and from active sludge in Tokyo by semi-quantifying the boron accumulation of each single-cultured bacterium. Intracellular boron concentrations ranged from 0.3 to 1.36 nmol g⁻¹ dry weight. Nineteen isolates identified by 16S rRNA gene sequence analysis were most closely related to the genera Bacillus , Variovorax , Pseudomonas , Shewanella , Mycobacterium and Rhodococcus . To our knowledge, this is the first study examining a wide range of bacterial strains in terms of boron accumulation.     

Isolation and identification of boron-accumulating bacteria from contaminated soils and active sludge

Abstract

High levels of boron are toxic to living organisms. The removal of boron from contaminated water is an important way of dealing with this environmental problem. For this purpose, we screened for bacteria that can absorb high levels of toxic boron from the environment. A range of boron-accumulating bacteria was isolated from boron-contaminated soil in Turkey, from uncontaminated soil in Tokyo, Japan, and from active sludge in Tokyo by semi-quantifying the boron accumulation of each single-cultured bacterium. Intracellular boron concentrations ranged from 0.3 to 1.36?nmol?g^?1 dry weight. Nineteen isolates identified by 16S rRNA gene sequence analysis were most closely related to the genera Bacillus, Variovorax, Pseudomonas, Shewanella, Mycobacterium and Rhodococcus. To our knowledge, this is the first study examining a wide range of bacterial strains in terms of boron accumulation.     

Isolation of a series of apocarotenoids from the fruits of the red paprika Capsicum annuum L

Eleven apocarotenoids (1-11) including five new compounds, 4, 6, 9, 10 and 11, were isolated from the fruits of the red paprika Capsicum annuum L. The structures of new apocarotenoids were determined to be apo-14'-zeaxanthinal (4), apo-13-zeaxanthinone (6), apo-12'-capsorubinal (9), apo-8'-capsorubinal (10), and 9,9'-diapo-10,9'-retro-carotene-9,9'-dione (11) by spectroscopic analysis. The other six known apocarotenoids were identified to be apo-8'-zeaxanthinal (1), apo-10'-zeaxanthinal (2), apo-12'-zeaxanthinal (3), apo-15-zeaxanthinal (5), apo-11-zeaxanthinal (7), and apo-9-zeaxanthinone (8) which have not been previously found in paprika. These apocarotenoids were assumed to be oxidative cleavage products of C(40) carotenoid such as capsanthin in paprika.     

氧化乐果降解菌的分离与初步鉴定

利用氧化乐果无机盐培养基通过长期的摇床驯化培养，从污染土壤中筛选出了可以在高浓度氧化乐果环境下生长的菌株，并通过固体和液体培养以及有机磷显色反应最终筛选出两种生长较好的菌株，初步鉴定为曲霉，通过定量生物降解实验研究发现，在温度28℃，自然pH值，摇床150r／min，氧化乐果初始浓度为2000μg／mL，培养时间为10d，两种菌株对氧化乐果的降解率分别为70．38％和61．28％，具有很高的潜在应用价值。     

Isolation and identification of 2-methoxy-3,5-dimethylpyrazine, a potent musty compound from wine corks

The compound responsible for a "fungal must" taint evident in industry assessments of wine corks was identified as 2-methoxy-3,5-dimethylpyrazine. The identification was made on the basis of gas chromatography/odor analyses, collection of material using micropreparative techniques, determination of chemical properties of collected material, and comparison by gas chromatography/mass spectrometry with an authentic sample, synthesized from 2-hydroxy-3,5-dimethylpyrazine. 2-Methoxy-3,5-dimethylpyrazine is an extremely potent compound with an unpleasant, musty, moldy aroma and an aroma threshold in a white wine of 2.1 ng/L. While its contribution to the frequency and intensity of cork taint in bottled wine is yet to be established, it has been assessed by some wine industry personnel as second only to 2,4,6-trichloroanisole as a cause of cork taint in Australian wine.     

Isolation and identification of oligomers from partial degradation of lime fruit cutin

Complementary degradative treatments with low-temperature hydrofluoric acid and methanolic potassium hydroxide have been used to investigate the protective biopolymer cutin from Citrus aurantifolia (lime) fruits, augmenting prior enzymatic and chemical strategies to yield a more comprehensive view of its molecular architecture. Analysis of the resulting soluble oligomeric fragments with one- and two-dimensional NMR and MS methods identified a new dimer and three trimeric esters of primary alcohols based on 10,16-dihydroxyhexadecanoic acid and 10-oxo-16-hydroxyhexadecanoic acid units. Whereas only 10-oxo-16-hydroxyhexadecanoic acid units were found in the oligomers from hydrofluoric acid treatments, the dimer and trimer products isolated to date using diverse degradative methods included six of the seven possible stoichiometric ratios of monomer units. A novel glucoside-linked hydroxyfatty acid tetramer was also identified provisionally, suggesting that the cutin biopolymer can be bound covalently to the plant cell wall. Although the current findings suggest that the predominant molecular architecture of this protective polymer in lime fruits involves esters of primary and secondary alcohols based on long-chain hydroxyfatty acids, the possibility of additional cross-linking to enhance structural integrity is underscored by these and related findings of nonstandard cutin molecular architectures.