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1.
Identification and isolation of (R(S)R(C))-S-(methylthiomethyl)cysteine-4-oxide from rhizomes of Tulbaghia violacea Harv. is reported. The structure and absolute configuration of the amino acid have been determined by NMR, MALDI-HRMS, IR, and CD spectroscopy. Its content varied in different parts of the plant (rhizomes, leaves, and stems) between 0.12 and 0.24 mg g(-1) fr. wt, being almost equal in the stems and rhizomes. In addition, S-methyl- and S-ethylcysteine derivatives have been detected in minute amounts (<3 microg g(-1) fr. wt) in all parts of the plant. The enzymatic cleavage of the amino acid and subsequent odor formation are discussed. 2,4,5,7-Tetrathiaoctane-4-oxide, the primary breakdown product, has been detected and isolated for the first time.  相似文献   

2.
S-alk(en)yl-L-cysteine sulfoxides, alliinase and aroma in Leucocoryne   总被引:1,自引:0,他引:1  
Levels of S-alk(en)yl-L-cysteine sulfoxides, alliinase and enzymatically generated pyruvic acid were determined in the bulb, leaf and scape of five species and a natural hybrid of Leucocoryne (Liliaceae), a genus of ornamental geophytes indigenous to Chile. (+)-S-Methyl-L-cysteine sulfoxide (MCSO) was present in all plant parts of all species at levels between 0.09 and 1.41 mg g(-1) fr. wt. Trans-(+)-S-(1-propenyl)-L-cysteine sulfoxide (PRENCSO) was present in plant parts of three species only (L. angustipetala, L. oadorata and L. purpurea) at levels between 0.12 and 1.82 mg g(-1) fr. wt. No other S-alk(en)yl-L-cysteine sulfoxides were detected. Alliinase (EC 4.4.1.4) was detected in the leaf, bulb and scape of L. angustipetala and L. purpurea, only in the leaves of L. coquimbensis and L. purpurea x L. coquimbensis, and only in the bulb of L. odorata. Enzymatically generated pyruvic acid was detected in all plant parts of all species at levels between trace amounts and 5.33 micromol g(-1) fr. wt. As PRENCSO is produced only in Leucocoryne species exhibiting a strong and unpleasant onion-like aroma, it is probable that the enzymatic degradation of PRENCSO is the main cause of that aroma. Consequently, Leucocoryne cultivars should be selected in species and hybrids that lack the ability to synthesise PRENCSO.  相似文献   

3.
The distribution pattern of phenylphenalenone-type compounds was investigated in vegetative and reproductive organs of Xiphidium caeruleum. The highest total molar concentration, up to 30 micromol g(-1) fr. wt, was detected in the root tip and the stamen. Accumulation of specific phenylphenalenone-related metabolites including glycosides was found in the hypogeal plant parts, the leaves, and the reproductive organs of the inflorescence. Putative biosynthetic relationships and the role of these compounds in plant defence are discussed.  相似文献   

4.
The effect of seaweed liquid fertilizers (SLF) of Sargassum wightii and Caulerpa chemnitzia on growth and biochemical constituents of Vigna sinensis was studied. The seeds soaked with aqueous extract of seaweeds performed better when compared to the water soaked controls. Hundred per cent germination was recorded both in aqueous extract soaked and water soaked treatments. The low concentration (20%) of aqueous extracts of S. wightii and C. chemnitzia promoted the seedling growth including the parameters of shoot length (15.87, 14.13 cm/seedling), root length (6.42, 5.38 cm/seedling), fresh weight (4.017, 4.012 g/seedling) and dry weight (0.878, 0.865 g/seedling), chlorophyll (1.599, 1.491 mg g-1 fr. wt.), carotenoids (0.899, 0.875 mg g-1 fr. wt.), protein content of shoot (3.956, 3.474 mg g-1 fr. wt.) and root (2.926, 2.890 mg g-1 fr. wt.), amino acid content of shoot (1.447, 1.429 mg g-1 fr. wt.) and root (0.698, 0.680 mg g-1 fr. wt.), reducing sugar content of shoot (6.426, 6.233 mg g-1 fr. wt.) and root (5.118, 5.103 mg g-1 fr. wt.), total sugar content of shoot (11.846, 11.350 mg g-1 fr. wt.) and root (10.368, 10.102 mg g-1 fr. wt.), alpha-amylase (1.927, 1.819 microg min-1 mg-1 protein) and beta-amylase (1.730, 1.617 microg min-1 mg-1 protein) activities in V. sinensis. Among the two seaweeds tested, S. wightii exhibited better responses.  相似文献   

5.
Kubec R  Kim S  Musah RA 《Phytochemistry》2002,61(6):675-680
Three cysteine derivatives, (R)-S-(2-hydroxyethyl)cysteine, together with (R(S)R(C))- and (S(S)R(C))-S-(2-hydroxyethyl)cysteine sulfoxides, have been isolated from the roots of Petiveria alliacea. Furthermore, three additional amino acids, S-methyl-, S-ethyl-, and S-propylcysteine derivatives, were detected. They were present only in trace amounts (<3 microg g(-1) fr. wt), precluding determination of their absolute configurations and oxidation states. In addition, four thiosulfinates, S-(2-hydroxyethyl) (2-hydroxyethane)-, S-(2-hydroxyethyl) phenylmethane-, S-benzyl (2-hydroxyethane)- and S-benzyl phenylmethanethiosulfinates, have been found in a homogenate of the roots. The formation pathways of various benzyl/phenyl-containing compounds previously found in the plant were also discussed.  相似文献   

6.
Secondary metabolites, DIBOA, HBOA, 7-OH-HBOA and BOA, were isolated and quantified from S. dulce (Nees), a native species in Chile belonging to the Acanthaceae family. The highest DIBOA and HBOA contents were determined in leaves (9.25 mmol kg(-1) fr. wt) and root (6.81 mmol kg(-1) fr. wt), respectively. Aglycones, 7-OH-HBOA and HBOA, were isolated together from root extracts of Acanthaceae species. Both, HBOA and 7-OH-HBOA should be direct precursors in the biosynthesis of DIBOA and DIMBOA, respectively.  相似文献   

7.
On feeding 14CO2 to the shoots of lupine (25 mCi per plant) 30 min was the minimal time needed to determine the incorporation of label into bacteroid compounds. The predominant incorporation, exhibited in all root, nodule and bacteroid samples after 30 min exposure, was into sucrose (45–90% of the corresponding fraction radioactivity) of the neutral fraction; into malate (30–40%) of the acid fraction; into aspartic acid and asparagine (60–80% in sum) of the basic fraction. The composition of carbon compounds containing the greatest amount of 14C in the cytosol of nodules and in bacteroids was similar. Their radioactivity after 30 min exposure was for bacteroids (nCi per g of bacteroid fr. wt): sucrose 5.73, glucose 1.00, malate 0.15, succinate 0.11; for the nodule cytosol (nCi per g of nodule fr. wt): sucrose 200.00, glucose 8.40, malate 9.34, succinate 8.50. Thus it was demonstrated that in lupine, sucrose is the main photoassimilate entering not only into nodules but also into bacteroids. The biosynthesis of aspartic acid and asparagine occurs during nitrogen fixation in bacteroids.  相似文献   

8.
Secondary metabolites 2,4‐dihydroxy‐l,4‐benzoxazin‐3‐one(DIBOA) and 2‐benzoxazolinone (BOA) were quantified in different morphological parts of A. mollis. The highest DIBOA content was determined in the stamens of the flowers (57.0 umol g?1 fr. wt). Content of DIBOA in leaves decreased from approximately 28 μmol g?1 fr. wt for younger leaves (less than 4 wk old), to 3.0 μmol g?1 fr. wt. for the older ones (more than 13 wk of age). The concentration of BOA was lower than that of DIBOA in all parts of the plant (less than 1.5 μmol g?1 fr. wt) and showed a small variation. Younger leaves exhibit antifeeding activity against the larvae of Pseudaletia impuncta a native moth that feeds on cereals. These results suggest that DIBOA protects A. mollis species from phytophagous insects.  相似文献   

9.
The common ice plants (Mesembryanthemum crystallinum) at the stage of five leaf pairs were exposed to cadmium chloride solutions (1, 0.1, and 0.01 mM) under the conditions of water culture. After five days, the partition of cadmium and iron in the plant organs and in the cell structures of the apical root region were investigated. Plant adaptation to excess cadmium in the environment was assessed by an increase in the leaf and root weight, a change in peroxidase activity, and an accumulation of proline. The common ice plant accumulated cadmium mainly in the root system. At a high concentration of cadmium in the nutrient solution (1 mM), its content in the root exceeded 2 g/kg fr wt, while at a concentration of 0.01 mM, it was as low as 10 mg/kg. Dithizone staining of transverse sections of the root apical region showed that, after a 48-h-long exposure of plants to 0.1 mM cadmium chloride, cadmium was localized in the cell walls of endodermis and metaxylem. The level of cadmium in leaves varied from 0.5 to 18 mg/kg fr wt. However, there was only a weak correlation between cadmium accumulation and the extent of a biomass decrease in the leaves of various stories, when cadmium concentration in the medium (1 mM cadmium chloride) was toxic. This fact could be related to a marked efflux of endogenous iron from old leaves into the young ones and to a change in the cadmium/iron ratio in the tissues. Proline accumulation in the third leaf pair and in the roots occurred at a relatively low cadmium content (10–12 mg/kg fr wt) in these organs. Maxima of activity of all three forms of peroxidase, viz., soluble, ionically-bound, and covalently-bound peroxidases, in roots were found at a high accumulation of cadmium in these organs (45 mg/kg fr wt). These maxima exceeded 3–4-fold the activity in aging leaves containing 5 mg cadmium/kg fr wt. A decrease in peroxidase activity in leaves was accompanied by a 3.3-fold decrease in iron content; thus, it could be caused by a deficiency of available iron necessary for the enzyme functioning. It was concluded that the resistance of Mesembryanthemum crystallinum, a halophyte, to excess cadmium content in the medium was achieved by its predominant accumulation in roots, where excess cadmium is compartmentalized in the apoplast and seems to be subjected to detoxification through pectate formation. Moreover, the leaves and, particularly, the roots are characterized by a high activity of the antioxidant systems, such as guaiacol-dependent peroxidases, and an occurrence of proline at modest cadmium concentrations.  相似文献   

10.
From the pollen of Zea mays, three brassinosteroids, castasterone, typhasterol and teasterone, were identified by GC/MS and/or 1H NMR. Their concentrations in the pollen were shown by GC/SIM to be about 120 μg/kg fr.wt. (castasterone), 6.6 μg/kg fr.wt. (typhasterol) and 4.1 μg/kg fr.wt. (teasterone). It was also found that the anther contained a fairly large amount of brassinosteroids by a bioassay.  相似文献   

11.
Bieleski RL 《Plant physiology》1968,43(8):1297-1308
The duckweed Spirodela oligorrhiza was grown in sterile nutrient solutions that contained 1 mm phosphate-(32)P at various specific activities. In solutions with activities higher than 2 muc per mumole per ml, plant growth was inhibited after a time, and the physical appearance of the plants was affected. The critical level of radiation, at which growth was first affected, corresponded to 5 kilorads.Plants were grown for 9 days (5 generations) in a culture solution containing phosphate at 0.5 muc per mumole per ml (radiation load approx 0.5 kilorads) so that all phosphorus-containing materials in the tissue became uniformly labeled. The various radioactive compounds were extracted, chromatographed, identified, and their radioactivity was measured. From this radioactivity plus the specific activity of the supplied phosphate, the amount of each compound was calculated. The data constitute a complete balance-sheet for phosphorus in a plant tissue. The identity of 98% of the phosphorus in the tissue was determined. Inorganic phosphate (32,700 mmumoles/g fr wt) was the predominant phosphorus-containing compound; RNA (5100 mmumoles P/g fr wt) was the main organic phosphate; phosphatidyl choline (1600 mmumoles/g fr wt) was the main phospholipid, and glucose-6-phosphate (500 mmumoles/g fr wt) the main acid-soluble phosphate ester. Amounts of other phosphorus compounds are given.  相似文献   

12.
Extraction and analytical methods have been refined and newones devised to allow precise determinations by GC-EC of thelevels of abscisic acid (ABA) and indol-3ylacetic acid (IAA)in samples of maize root tips as small as 1.0 g fr. wt. Seminalroots of 5-d-old maize seedlings grown in normal (bulk density1200 kg m–3) and compacted (bulk density 1600 kg m–3)sand/garden loam mixtures have been examined. Seminal rootsfrom compacted soil had an average length of about 40% of thatof control roots and were much thicker. The ABA levels in 10mm tips of impeded roots (c. 25–35 ng g–1 fr.wt.)did not differ significantly from those of normal root tipson both a fresh and dry weight basis. The levels in 0–1mm tips were approximately double those in the remaining 1–10mm zones. IAA levels were increased by about 3 times in impededroots (176.3 as compared with 52.4 ng g–1 fr.wt) and itis concluded that this response is likely to be the main causeof the morphological and growth changes brought about by soilcompaction.  相似文献   

13.
Quaternary ammonium compounds in plants in relation to salt resistance   总被引:3,自引:0,他引:3  
Fourteen plant species exhibiting a wide range of salt resistance as halophytes, semi-resistant glycophytes and sensitive glycophytes, have been grown in nutrient solution culture under low and high salt conditions. Inorganic analyses and shoot sap osmotic pressure values of these plants confirm that osmotic compensation at high salt levels is largely achieved by the accumulation of Na salts. Choline was found in shoots and roots in the range 1.0-0.2 μmol g fr. wt?1 and varied little following salt stress. Trigonelline was found in some of the sensitive glycophytes and did not increase significantly in stressed plants. Betaine levels were high (10 μmol g fr. wt?1) in the shoot of the halophytes at low salt conditions, lower values (1–10 μmol g fr. wt?1) were found in the semi-resistant glycophytes and none detected in the sensitive glycophytes. In the two resistant groups betaine accumulated to higher levels following NaCl stress. Shoot betaine levels always exceeded root levels. Proline occurred in all plants and in all cases was accumulated following NaCl stress.  相似文献   

14.
Light-induced formation of singlet oxygen selectively oxidizes methionines in the heavy chain of IgG2 antibodies. Peptide mapping has indicated the following sensitivities to oxidation: M252 > M428 > M397. Irrespective of the light source, formulating proteins with the free amino acid methionine limits oxidative damage. Conventional peptide mapping cannot distinguish between the S- and R-diastereomers of methionine sulfoxide (Met[O]) formed in the photo-oxidized protein because of their identical polarities and masses. We have developed a method for identification and quantification of these diastereomers by taking advantage of the complementary stereospecificities of the methionine sulfoxide reductase (Msr) enzymes MsrA and MsrB, which promote the selective reduction of S- and R-diastereomers of Met(O), respectively. In addition, an MsrBA fusion protein that contains both Msr enzyme activities permitted the quantitative reduction of all Met(O) diastereomers. Using these Msr enzymes in combination with peptide mapping, we were able to detect and differentiate diastereomers of methionine sulfoxide within the highly conserved heavy chain of an IgG2 that had been photo-oxidized, as well as those in an IgG1 oxidized with peroxide. The rapid identification of the stereospecificity of methionine oxidation by Msr enzymes not only definitively differentiates Met(O) diastereomers, which previously has been indistinguishable using traditional techniques, but also provides an important tool that may contribute to understanding of the mechanisms of protein oxidation and development of new formulation strategies to stabilize protein therapeutics.Key words: immunoglobulin gamma antibody, methionine sulfoxide, oxidation, photo-oxidation, methionine sulfoxide reductase  相似文献   

15.
《MABS-AUSTIN》2013,5(3):299-308
Light-induced formation of singlet oxygen selectively oxidizes methionines in the heavy chain of IgG2 antibodies. Peptide mapping has indicated the following sensitivities to oxidation: M252 > M428 > M397. Irrespective of the light source, formulating proteins with the free amino acid methionine limits oxidative damage. Conventional peptide mapping cannot distinguish between the S- and R-diastereomers of methionine sulfoxide (Met(O)) formed in the photo-oxidized protein because of their identical polarities and masses. We have developed a method for identification and quantification of these diastereomers by taking advantage of the complementary stereospecificities of the methionine sulfoxide reductase (Msr) enzymes MsrA and MsrB, which promote the selective reduction of S- and R-diastereomers of Met(O), respectively. In addition, an MsrBA fusion protein that contains both Msr enzyme activities permitted the quantitative reduction of all Met(O) diastereomers. Using these Msr enzymes in combination with peptide mapping, we were able to detect and differentiate diastereomers of methionine sulfoxide within the highly conserved heavy chain of an IgG2 that had been photo-oxidized, as well as those in an IgG1 oxidized with peroxide. The rapid identification of the stereospecificity of methionine oxidation by Msr enzymes not only definitively differentiates Met(O) diastereomers, which previously has been indistinguishable using traditional techniques, but also provides an important tool that may contribute to understanding of the mechanisms of protein oxidation and development of new formulation strategies to stabilize protein therapeutics.  相似文献   

16.
BACKGROUND AND AIMS: Condensed tannins (CTs) in the diet affect consumers in a concentration-dependent manner. Because of their importance in plant defence against herbivores and pathogens as well as their potential application against gastrointestinal parasites of ruminants in agronomy, an understanding of the seasonal dynamics of CT concentrations during plant growth is essential. METHODS: Over a vegetation period, CT concentrations in leaves, stems and roots and the biomass proportions between these organs were investigated in Onobrychis viciifolia, Lotus corniculatus and Cichorium intybus. Based on the experimental data, a model has been suggested to predict CT concentrations in harvestable biomass of these species. KEY RESULTS: During the experiment, leaf mass fractions of plants decreased from 85, 64, 85 to 30, 18, 39 % d. wt in Onobrychis, Lotus and Cichorium, respectively, and proportions of stems and roots increased accordingly. While CT concentrations almost doubled in leaves in Onobrychis (from 52 to 86 mg g(-1) d. wt, P<0.001) and Lotus (from 25 to 54 mg g(-1) d. wt, P<0.001), they were stable at low levels in expanding leaves of Cichorium (5 mg g(-1) d. wt) and in stems and roots of all investigated species. Due to an inverse effect of the increasing CT concentrations in leaves and simultaneous dilution from increasing proportions of 'CT-poor' stems, CT concentrations in harvestable biomass were stable over time in all investigated species: 62, 26 and 5 mg g(-1) d. wt for Onobrychis, Lotus and Cichorium, respectively. CONCLUSIONS: As a consequence of the unequal distribution of tannins in different plant parts and due to the changing biomass proportions between them, various herbivores (e.g. a leaf-eating insect and a grazing ruminant) may find not only different concentrations of CT in their diets but also different CT dynamics during the season. For the prediction of seasonal variations of CT concentrations, biomass allocation and accumulation of none-CT plant material are likely to be as important predictors as the knowledge of CT synthesis and its regulation.  相似文献   

17.
Root cultures of Senecio vulgaris, S. vernalis, S. erucifolius and S. squalidus were established. The patterns of pyrrolizidine alkaloids found in these root cultures were analyzed by high-resolution GC and GC-MS and compared with the alkaloids present in the respective plants. In vitro cultured roots produce alkaloid patterns and accumulate quantities which are comparable to those found in soil grown plants. With the exception of the otonecine derivative senkirkine all pyrrolizidines accumulate as N-oxides. Only senkirkine is partially released into the medium. The cultures incorporate biosynthetic precursors, e.g. 14C-labelled putrescine or spermidine with high efficiency into the alkaloids. Senecionine N-oxide was found to be the main product of biosynthesis. Evidence is presented that senecionine N-oxide is directly transformed into senkirkine, the main alkaloid of S. vernalis root cultures.Abbreviations GC Gas chromatography - MS Mass spectroscopy - PND Phosphorous-Nitrogen-Detector - FID Flame Ionization Detector - fr.wt Fresh weight  相似文献   

18.
Glycosylation of hesperetin by plant cell cultures   总被引:3,自引:0,他引:3  
Shimoda K  Hamada H  Hamada H 《Phytochemistry》2008,69(5):1135-1140
The biotransformation of hesperetin by cultured cells of Ipomoea batatas and Eucalyptus perriniana was investigated. Three glycosides, hesperetin 3'-O-beta-D-glucopyranoside (33 microg/g fr. wt of cells), hesperetin 3',7-O-beta-D-diglucopyranoside (217 microg/g fr. wt of cells), and hesperetin 7-O-[6-O-(beta-D-glucopyranosyl)]-beta-d-glucopyranoside (beta-gentiobioside, 22 microg/g fr. wt of cells), together with three hitherto known glycosides, hesperetin 5-O-beta-d-glucopyranoside (23 microg/g fr. wt of cells), hesperetin 7-O-beta-D-glucopyranoside (57 microg/g fr. wt of cells), and hesperetin 7-O-[6-O-(alpha-L-rhamnopyranosyl)]-beta-D-glucopyranoside (beta-rutinoside, hesperidin, 13 microg/g fr. wt of cells), were isolated from cultured suspension cells of E. perriniana that had been treated with hesperetin. Oligosaccharide chains were regioselectively formed at the C-7 position of hesperetin to afford beta-gentiobioside and beta-rutinoside. On the other hand, cultured I. batatas cells converted hesperetin into hesperetin 3'-O-beta-D-glucopyranoside (60 microg/g fr. wt of cells), hesperetin 5-O-beta-D-glucopyranoside (23 microg/g fr. wt of cells), and hesperetin 7-O-beta-D-glucopyranoside (110 microg/g fr. wt of cells).  相似文献   

19.
The contents of lipids and pigments were compared in juvenile and adult algae Costaria costata [Turn.] Saund (Laminariaceae) collected in April. The total content of lipids and that of particular lipid classes increased markedly with age. In adult algae, the contents of total lipids, glyceroglycolipids, and neutral lipids doubled as compared with juvenile algae and was equal to 5.70, 1.78, and 0.81 mg/g fr wt, respectively. The content of free sterols increased with age by three times; it was equal to 0.11 mg/g fr wt in juvenile algae and 0.38 mg/g fr wt in adult algae. Total content of phospholipids changed with age to a lesser extent: 0.72 mg/g fr wt in juvenile vs. 0.92 mg/g fr wt in adult algae. Substantial changes were observed in the content of particular polar lipids. The absolute amounts of monogalactosyldiacylglycerols, sulfoquinovosyldiacylglycerols, digalactosyldiacylglycerols, phosphatidylcholines, phosphatidylglycerols, and phosphatidylinosites increased markedly with age, whereas the amount of phosphatidyl-O[N-(2-hydroxyethyl)glycines] declined. The amount of phosphatidylethanolamines did not depend on algal age. A small amount of diphosphatidylglycerols was detected only in juvenile algae. The content of photosynthetic pigments (carotenoids and chlorophylls) approximately doubled with age and, in adult algae, was equal to 0.57 and 1.23 mg/g fr wt, respectively. Total lipids of juvenile and adult algae did not differ in fatty acid composition. At all developmental stages, polyunsaturated fatty acids predominated early in spring and comprised about 80% of fatty acids. The acids of ω-3-series predominated among them.  相似文献   

20.
Summary Transformed cultures of opium poppy (Papaver somniferum L.) were established by infecting hypocotyl segments with Agrobacterium rhizogenes MAFF 03-01724. Undifferentiated calli formed on the infected site grew satisfactorily on phytohormone-free solid medium in the dark and produced opine, mikimopine, which could not be detected in a normal culture. Numerous adventitious shoots developed from transformed calli during subculture. The transformed shoots separated individually were cultured on phytohormone-free MS solid medium at 22 ° C under 14 h/day light. They displayed wider leaves and longer internodes than shoots established from seeds or non-transformed root culture. The content of morphinan alkaloids in the cultures and regenerated shoots were quantitatively analyzed by enzyme-linked immunosorbent assay and high performance liquid chromatography. HPLC analysis revealed that non-transformed shoots contained much more codeine (1310 gmg/g dry wt.) than morphine (50 g/g dry wt.), while the transformed shoot cultures did not contain morphine, although the level of morphinan alkaloids in the transformed shoots (213 g morphine equivalents/g fr. wt.) was comparable to that in non-transformed shoots (182 g morphine equivalents/g fr. wt.) by ELISA.Abbreviations MS Murashige-Skoog (Murashige and Skoog 1962) - 1/2 MS half strength MS - HF phytohormone-free - NAA 1-naphthaleneacetic acid - ELISA enzyme-linked immunosorbent assay - HPLC high performance liquid chromatography  相似文献   

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