Immature Seeds Of Phaseolus Vulgaris Research Articles

Stereoisomers of Castasterone, 3-Epicastasterone and 2,3-Diepicastasterone, in Immature Seeds of Phaseolus vulgaris

A capillary GC-MS analysis revealed that two stereoisomers of castasterone are contained in immature seeds of Phaseolus vulgaris. 400 MHz proton NMR analysis of the stereoisomers determined they are A ring epimers of castasterone, 3-epicastasterone and 2,3-diepicastasterone. In rice lamina inclination assay, 3-epicastasterone and 2,3-diepicastasterone showed reduced biological activity than that of castasterone. Together with our previous finding that 2-epicastasterone exhibits a less biological activity than CS, this result indicates that epimerization of hydroxyl at C-2 or/and C-3 is/are inactive processes to reduce biological activity of CS after exerting as a bioactive brassinosteroid in P. vulgaris.

ChemInform Abstract: 2‐Deoxy‐25‐methyldolichosterone (Ia) and 3‐epi‐2‐Deoxy‐25‐methyldolichosterone (Ib) in Immature Seeds of Phaseolus vulgaris

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Characterization of 2‐Epicastasterone from Immature Seeds of Phaseolus vulgaris

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Characterization of 2-Epicastasterone from Immature Seeds of Phaseolus vulgaris

), most likely from an A ring methaneboronate. Coupled with a distinct retention time on GC from that of CS BMB, our findings suggest that the compound is an isomer of CS.In a 400 MHz proton NMR study (Table 2), absorptions for four methyls (C-21, C-26, C-27 and C-28) and two protons at C-22 and C-23 in the side chain of the isomer of CS were exactly the same as those of CS, indicating that the side chain structure of the isomer is identical to that of CS. In addition, signals for H

2-Deoxy-25-methyldolichosterone and 3-epi-2-Deoxy-25-methyldolichosterone in Immature Seeds of Phaseolus vulgaris

2-Deoxy-25-methyldolichosterone and 3-epi-2-Deoxy-25-methyldolichosterone in Immature Seeds of Phaseolus vulgaris

Identification of a new brassinosteroid, 23-dehydro-2-epicastasterone, from immature seeds ofPhaseolus vulgaris

Identification of a new brassinosteroid, 23-dehydro-2-epicastasterone, from immature seeds ofPhaseolus vulgaris

Characterization of C29-Brassinosteroids and Their Biosynthetic Precursors in Immature Seeds of Phaseolus vulgaris

Brassinosteroids (BRs) are unique steroids which show hormonal actions in plant growth and development. The BRs can be classified into C27, C28 and C29 based on their carbon skeleton. Metabolic and molecular genetic studies revealed that the C28-BRs are generated from campesterol (CR). Recently, we demonstrated that a C27-BR, 28-norcastasterone (28-norCS) is biosynthesized from cholesterol (CHR) that carries an identical carbon skeleton to that of 28norCS. These results suggested that the C29-BRs are also biosynthesized from a phytosterol carrying the same skeleton as that of the C29-BRs. Solid evidence to support this notion, however, is not yet to be obtained. This deficiency has prompted us to investigate the presence of BRs with a C-24 ethyl group and their potent biosynthetic precursors in the immature seeds of Phaseolus vulgaris wherein 24α-ethylcholesterol, sitosterol (STR), is a major sterol, which provides a clue for possible C29-BRs biosynthesis in plants. As summarized in Table 1, the strongest peak on the total ion chromatogram (TIC) at 17.29 min gave a mass spectrum at m/z 486 (M), 471, 396, 381, 357, 255, 213, 145 and 129 whose mass spectrum and retention times on GC are identical to those of authentic 24S-ethylcholesterol (STR) trimethylsilyl (TMSi) ether, demonstrating that the compound is STR. On TIC, a peak appeared at 17.57 min showing a molecular ion at m/z 488 and prominent ions at m/z 473, 398, 383, 359, 257, 215, 147 and 131. The molecular ion and characteristic ions in the TMSi compound are 2 mass increased than those of sitosterol TMSi, suggesting that the compound is dihydro-sitosterol, most likely sitostanol (STN). As shown in Table 2, 300 MHz proton NMR of the acetylated STN compound gave the key proton resonances at δ 0.64 (Me -18, s), 0.81 (Me -19, s), 4.68 (H-3, m), 2.02 (3-OAc, s), 0.90 (Me -21, d, J = 6.6 Hz), 0.85 (Me -26, d, J = 7.2 Hz), 0.83 (Me -27, d, J = 7.2 Hz) and 0.80 (Me -29, d, J = 5.7 Hz). The signals for H-4 (δ 2.32, d) and H-6 (δ 5.38, m) in STR-acetate were not observed in the compound, however, indicating that a double bond between C-5 and C-6 in STR acetate is not present in the compound. By saturating the ring structure, most of the aforementioned proton signals from the compound are upfield shifted compared to those from STR-acetate. The downfield shifted signal for H-3 is also understandable because the absorption of H-3 (δ 4.60 m) derived from CHR-acetate is downfield shifted to δ 4.69 (m) by diminishing the double bond at C-5. Taken together, the compound is undoubtedly STN-acetate, determining that the natural structure of the compound is STN. The ethyl acetate soluble fraction (64 g) obtained from immature seeds of P. vulgaris was purified by several

ChemInform Abstract: Identification of Brassinosteroids with 24R‐Methyl in Immature Seeds of Phaseolus vulgaris.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Partial Purification of a cis-trans-Isomerase of Zeatin from Immature Seed of Phaseolus vulgaris L.

Investigation of the conversion of exogenous cis-zeatin to trans-zeatin in immature seeds of Phaseolus vulgaris L. led to the isolation of a cis-trans-isomerase from the endosperm. The enzyme was purified more than 2000-fold by chromatography on a series of fast protein liquid chromatography (anion exchange, gel filtration, and hydrophobic interaction) and concanavalin A columns. The enzymic reaction favors conversion from the cis to the trans form and requires flavin, light, and dithiothreitol. cis-Zeatin riboside is also a substrate for the enzyme. Retention on the concanavalin A column indicated that the enzyme is a glycoprotein. The enzyme was stable for at least 8 weeks when stored at -80[deg] C. The occurrence of cis-trans-isomerization suggests that cis-zeatin and cis-zeatin riboside formed by tRNA degradation could be precursors of biologically active cytokinins.

Cytolocalization of zeatin O-xylosyltransferase in Phaseolus.

Zeatin O-xylosyltransferase (EC 2.4.2.-) mediates the formation of O-xylosylzeatin from trans-zeatin and UDP-xylose in immature seeds of Phaseolus vulgaris. Tissue printing with a monoclonal antibody specific for the enzyme and a cDNA probe demonstrated that the enzyme was primarily localized and synthesized in the endosperm. Immunolocalization performed on monolayer endosperm at the free-nuclei stage and on EM sections demonstrated that the enzyme was associated with the nucleus as well as with the cytoplasm. Immunoanalysis of nuclear fractions revealed that the enzyme was retained in the nuclear pellet. Western analysis also showed that the enzyme was present in the nuclei of cotyledons and endosperm callus. The findings suggest that the enzyme may be involved in the nuclear-cytoplasmic transport of cytokinins and related molecules or, possibly, with chromatin of rapidly dividing cells.

Effects of 3-Methylgibberellin Analogs on Gibberellin 3β-Hydroxylases and Plant Growth.

Six 3-methylgibberellin analogs were synthesized, and their effects on the GA 3β-hydroxylases from immature seeds of Phaseolus vulgaris and Cucurbita maxima, and/or on the growth of dwarf rice (Oryza sativa L. cv. Tan-ginbozu) and cucumber (Cucumis sativus L. cv. Spacemaster) were investigated. 3-Methyl-GA5 and 2, 3-didehydro-3-methyl-GA9· inhibited the conversion of [2, 3-(3)H2]GA9 to [2-(3)H]GA4 by GA 3β-hydroxylases from both P. vulgaris and C. maxima at 3 μM and higher. Their C/D-ring-rearranged isomers, 2, 3-didehydro-3-methyl-DGC and 16-deoxo-2, 3-didehydro-3-methyl-DGC, inhibited 3β-hydroxylation by the enzyme from P. vulgaris threefold more strongly than the non-C/D-ring-rearranged compounds, but exhibited no effect on 3β-hydroxylation by the enzyme from C. maxima. In a dwarf rice seedling assay, 3-methyl-GA5 and 2, 3-didehydro-3-methyl-GA9 promoted shoot elongation at doses of 300 ng/plant and higher, and 3α-methyl-GA1 and 3α-methyl-GA4 at doses of 30 ng/plant and higher. In contrast 2, 3-didehydro-3-methyl-DGC inhibited shoot growth to half that of the control at a dose of 300 ng/plant, and 16-deoxo-2, 3-didehydro-3-methyl-DGC showed no effect on growth. In a cucumber seedling assay, 3α-methyl-GA4 promoted hypocotyl elongation at doses of 300 ng/plant and higher. The other C-3 methyl compounds showed no effect on the hypocotyl elongation of cucumber seedlings.

Partial Purification and Characterization of the Gibberellin A20 3β-Hydroxylase from Seeds of Phaseolus vulgaris

The GA(20) 3beta-hydroxylase present in immature seeds of Phaseolus vulgaris has been partially purified and characterized. The physical characteristics of the enzyme are similar to those of the GA 2beta-hydroxylases present in mature and immature seeds of Pisum sativum. It is acid-labile, hydrophobic, and of M(r) 45,000. The enzyme catalyzes the synthesis of GA(1), GA(5), and GA(29) from GA(20). Activity is dependent upon the presence of Fe(2+), ascorbate, 2-oxoglutarate, and oxygen. 2-Oxoglutarate does not function as a cosubstrate; in the presence of the enzyme, succinate is not a reaction product.

4α,14α-Dimethyl-5α-ergosta-7,9(11),24(28)-trien-3β-ol from Phaseolus vulgaris and Gynostemma pentaphyllum

The structure of a new 4α-methylsterol isolated from the immature seeds of Phaseolus vulgaris and the aerial parts of Gynostemma pentaphyllum has been shown to be 4α,14α-dimethyl-5α-ergosta-7,9(11),24(28)-trien-3β-ol by spectroscopic methods and by chemical correlation with obtusifoliol. This appears to be the first report of the isolation of a 4α-methylsterol with a Δ 7,9(11)-diene system from nature. Abundances and chromatographic data of all identified 4α-methylsterols isolated from G. pentaphyllum are also given.

25-Methylgramisterol and other 4α-methylsterols from Phaseolus vulgaris seeds

Thestructures of five new 4α-methylsterols isolated from the immature seeds of Phaseolus vulgaris have been shown to be 25-methylgramisterol, 24 Z-ethylidene-4α-methyl-5α-cholest-8(14)-en-3β-ol, 24 E- and 24 Z- ethylidene-4α, 14α-dimethyl-5α-cholest-8-en-3β-ol and 24 Z-ethylidene-4α, 14α-dimethyl-5α-cholest-9(11)-en-3β-ol. In addition, four known but uncommon 4α-methylsterols, 28-isocitrostadienol, 4α-methylfecosterol, 24 Z-ethylidene-4α- methylcholest-8-en-3β-ol, and 24-methylene-4α, 14α-dimethyl-5α-cholest-9(11)-en-3β-ol, together with several common 4α-methylsterols were isolated from the seeds and identified.

Metabolism of gibberellins in a cell-free system from immature seeds of Phaseolus vulgaris L.

The biosynthetic steps from gibberellin A12-aldehyde (GA12-aldehyde) to C19-GAs were studied by means of a cell-free system from the embryos of immature Phaseolus vulgaris seeds. Stable-isotope-labeled GAs were used as substrates and the products were identified by gas chromatography-mass spectrometry. Gibberellin A12-aldehyde was converted to GA4 via non-hydroxylated intermediates and to GA1 via 13-hydroxylated intermediates. 13-Hydroxylation took place at the beginning of the pathway by the conversion of GA12-aldehyde to GA53-aldehyde. The conversion of GA20 to GA5 and GA6 was also shown but no 2β-hydroxylating activity was found. Endogenous GAs from embryos and testas of 17-dold seeds were re-examined by gas chromatography-selected ion monitoring using stable-isotopelabeled GAs as internal standards. Gibberellins A9, A12, A15, A19, A23, A24, and A53 were identified for the first time in P. vulgaris, in addition to GA1, GA4, GA5, GA6, GA8, GA17, GA20, GA29, GA37, GA38 and GA44, which were previously known to occur in this species. The levels of all GAs, except the 2β-hydroxylated ones, were greater in the embryos than in the testas. Conversely, the contents of GA8 and GA29, both 2β-hydroxylated, were much higher in the testas than in the embryos.

Conversion of gibberellin A20 to gibberellins A1 and A5 in a cell-free system from Phaseolus vulgaris

The soluble fraction of a cell-free system from immature seeds of Phaseolus vulgaris L. converts gibberellin A20 (GA20) to GA1 and GA5. It does however not metabolize GA1 and GA29 to GA5, showing that in this system GA20 is converted directly to GA5. The steps from GA20 to GA1 (3-hydroxylation) and from GA20 to GA5 (Δ(2) double-bond formation) require oxygen, Fe(2+) and α-ketoglutarate, and are stimulated by ascorbate. The enzymes catalyzing these conversions bate. The enzymes catalyzing these conversions have properties similar to those of GA oxidases found in Cucurbita maxima and Pisum sativum.

Desiccation of Axes of Phaseolus vulgaris during Development of a Switch from a Development Pattern of Protein Synthesis to a Germination Pattern

Immature seeds of Phaseolus vulgaris removed from the pod at 32 days of development do not germinate unless first subjected to a desiccation treatment. This change from development to germination caused by premature drying is mirrored in the pattern of protein synthesis by the axes. Rehydrated axes from 32-day-developed seeds cease to synthesize proteins that are uniquely associated with development, but instead synthesize some proteins that are similar to those made in the germinating axes from mature dry seeds. Desiccation of 22-day-developed seeds does not lead to their germination, nor does it cause a switch from a developmental to a germination mode of protein synthesis by the axes. It is proposed that desiccation plays a role in permanently suppressing developmental protein synthesis and in inducing germination protein synthesis.