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1.
Biosynthesis of gibberellins A12, A15, A24, A36, and A37 by a cell-free system from Cucurbita maxima
GA12-aldehyde obtained from mevalonate via ent-kaurene, ent-kaurenol, ent-kaurenoic acid and ent-7α-hydroxykaurenoic acid in a cell-free system from immature seeds of Cucurbita maxima was converted to GA12 by the same system. When Mn2+ was omitted from the system GA12-aldehyde and GA12 were converted further to several products. Among these GA15, GA24, GA36 and GA37 were conclusively identified by GC-MS. With the exception of GA37 these GAs have not previously been found in higher plants. Another biosynthetic pathway led from ent-7α-hydroxykaurenoic acid to very polar products via what was tentatively identified as ent-6α, 7α-dihydroxykaurenoic acid. An unidentified component with an MS resembling that of a dihydroxykaurenolide was also obtained from incubations with mevalonate. 相似文献
2.
Reaction of gibberellin A3 (GA3) with carrier-free tritium gas and 5% palladium on calcium carbonate as catalyst gave a complex mixture of products, several of which were isolated and identified. Three of the purified products are the radioactive forms of naturally occurring gibberellins: [3H]GA3 (1), [3H]GA1 (2) and [3H]tetrahydro GA3 (4). Another substance was isolated and tentatively identified as [3H]16,17-dihydro GA3 (3). GLC was used to determine the specific activities of 1 and 2. [3H]GA3 likely arises from palladium catalysed nonspecific exchange of GA3 alkane hydrogen atoms with tritium. [3H]GA1 is also exchange labeled but most of its radioactivity is due to tritium addition to the C-1,2 olefinic bond of GA3. 相似文献
3.
Gordon V. Hoad Bernard O. Phinney Valerie M. Sponsel Jake Macmillan 《Phytochemistry》1981,20(4):703-713
C2- and C3-derivatives of GA4 and GA9 were tested for biological activity in a range of plant assays. The activity of most of these derivatives was equal to, or less than, that of the parent GAs. However, 2β-methylGA4 and 2,2-dimethylGA4 had a higher activity than GA4 in some assays and the latter derivative was shown to be the most active GA known to date in the Forward oat first leaf, Tan-ginbozu dwarf rice and d5-maize assays. Two other derivatives, 12,16-cycloGA9 and 19-desoxyGA9 had less activity than GA9. 相似文献
4.
Masaji Koshioka Richard P. Pharis Rod W. King Noboru Murofushi Richard C. Durley 《Phytochemistry》1985,24(4):663-671
The native gibberellin A5 (GA5), as [1-3H]GA5 (3.2 Ci/mmol) was fed to seed capsules (0.58 μCi/capsule) of Pharbitis nil cv Violet at the 2-week stage of development, and its metabolism in the seeds was investigated after 43 hr. Extractable radioactivity in free GA metabolites was 38%, with 56% in GA glucosyl conjugate-like substances. Only 2.5% of the extractable radioactivity remained as [3H]GA5. Tentative identifications, based on comparisons with authentic standards after sequential chromatography on silica gel partition column → gradient-eluted C18 HPLC → isocratic-eluted C18 HPLC-radiocounting (RC), showed that [3H]GA5 was converted to at least six free GAs, GA1, GA3, GA6, GA8, GA22, GA29, a GA5 methyl ester-like metabolite, and at least twelve GA glucosyl conjugate-like substances, GA5-glucoside (GA5-G), GA5-glucosyl ester (GA5-GE), GA1-O(3)-G, GA1-O(13)-G, GA1-GE, GA3-O(3)-G, GA3-O(13)-G, GA3-GE, GA6-G or GE, GA8-O(2)-G, GA22-G or GE and GA29-O(2)-G. After lower specific activity feeds of [1,2-3H]GA5 (74 mCi/mmol; 0.1 μCi/capsule) at approximately the same stage of development, the presence of GA1, GA3, GA5, GA6, GA8 and GA29 was further confirmed by sequential (after C18 HPLC-RC) capillary gas chromatography-selected ion monitoring (GC-SIM), using six characteristic ions. However, for GA22 only a trace of the parent ion was present at the appropriate retention time. 相似文献
5.
By GC-MS the following acidic constituents of the endosperm of Echinocystis macrocarpa were identified: abscisic acid and its trans,trans-isomer, 4′-dihydrophaseic acid, GA4, GA7, iso-GA7, GA24, GA25, two isomers of GA13, GA43, ent-6α,7α,17-trihydroxy-16αH-kauran-19-oic acid and ent-6α,7α, 16β, 17-tetrahydroxykauran- 19-oic acid. The structures of the last three new natural products were confirmed by partial synthesis. ent-Kaurene was detected in the neutral fraction. 相似文献
6.
Rick C. Heupel Bernard O. Phinney Clive R. Spray Paul Gaskin Jake MacMillan Peter Hedden Jan E. Graebe 《Phytochemistry》1985,24(1):47-53
The native hormones from tassels of maize (Zea mays) were re-investigated. The previous identification by GC/SIM of GA1, GA8 and GA29 in normal tassels was confirmed by full GC/MS scans at the correct Kovats retention indices. In tassels of dwarf-1 mutants, GA44,?GA19, GA17, GA20 and the 16,17-dihydro, 7β,16α,17-trihydroxy derivative of ent-kaurenoic acid were identified by GC/MS. Gibberellin A1 was not found in the mutant tassels. [14C]Gibberellin A53 was fed to tassels of the dwarf-5 mutant. In the ethyl acetate-soluble acidic fraction from the feeds, [14C]GA44 was identified by GC/MS; [14C]GA19 and [14C]GA29 were identified by GC/SIM. The GA29 is probably a metabolite of the feeds because the dwarf-5 mutant is known to control the step copalyl pyrophosphate to ent-kaurene in the maize GA-biosynthetic pathway and because GA29 was not identified in a control experiment. The n-butanol fractions obtained from the feeds were shown, by GC/MS, to contain [14C]GA53 after hydrolysis, suggesting that conjugated [14C]GA53 is a major metabolite from GA53 feeds. [17-13C, 17-3H2]Gibberellin A20 was fed to normal, dwarf-1 and dwarf-5 tassels. In each case, analysis of the purified ethyl acetate-soluble acidic extracts by GC/MS led to the identification of [13C]GA29 and unmetabolized [13C]GA20 in which no 13C-isotope dilution was observed. 相似文献
7.
Masaji Koshioka Alan Jones Mayumi N. Koshioka Richard P. Pharis 《Phytochemistry》1983,22(7):1585-1590
The native gibberellin A4 (GA4), in radioactive form ([1,2-3H]GA4, 1.06 Ci/mmol), was fed to carrot somatic cell cultures (suspension and immobilized cell systems) and its metabolism over a 48 hr period was investigated. It was found that the [3H]GA4 was metabolized to at least two GAs, [3H]GA1 and [3H]GA8, six GA glucosyl conjugates, [3H]GA1-0(3)-glucoside, [3H]GA1-0(13)-glucoside, [3H]GA1-glucosyl ester, [3H]GA4-glucoside, [3H]GA4-glucosyl ester, a [3H]GA8 glucosyl conjugate(s) and a previously unknown [3H]GA1 glucosyl conjugate ([3H]GA1-0(3,13)-diglucoside-like compound). The GA1-diglucoside-like compound was found only in extracts of cells and was present in significant amounts (33 % of total extractable radioactivity). All other metabolites were present in both cells and medium. For extracts of the medium, no differences between the suspension and immobilized cultures existed in types of [3H]GA4 metabolites although quantitative differences were apparent. 相似文献
8.
Gibberellin A14-[17-3H] applied to seedlings of dark grown dwarf pea (Pisum sativum L. cy. Meteor) was converted to GA1, GA8, GA18, GA23, GA28, and GA38. The sequence of interconversion of GA14→ GA18 → GA38 → GA23 → GA1 → GA8 is indicated. Identifications were made by gas-liquid radiochromatography using three liquid stationary phases. 相似文献
9.
Summary Two new gibberellins, gibberellins A26 and A27 (GA26 and GA27), and their glucosides have been isolated from immature seeds of Japanese morning-glory (Pharbitis nil), together with GA8 and its glucoside. GA26, GA27 and their glucosides showed only slight growth-promoting activities on seedlings of rice, dwarf maize and cucumber. 相似文献
10.
Gibberellin Structure-Dependent Interaction between Gibberellins and Deoxygibberellin C in the Growth of Dwarf Maize Seedlings
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Hashimoto T 《Plant physiology》1987,83(4):910-914
The effects of 3-deoxygibberellin C (DGC) on the growth-promoting actions of gibberellins A1, A2, A3, A4, A5, A7, A8, A9, A13, A18, A19, A20, and A23 (GAn) as well as 13-deoxygibberellin A5 (deoxy-GA5) were tested with seedlings of gibberellin-deficient dwarf mutants (d2 and d5) of maize (Zea mays L.). It was found that DGC promoted the actions of gibberellins having both C-1 double bond and C-3 axial hydroxyl group, and it inhibited the action of gibberellins having the saturated ring A and lacking the C-3 axial hydroxyl group, whereas it did not affect that of the ones having the hydroxyl group. The presence of C-2 double bond, as in GA5 and deoxy-GA5, diminished the inhibitory action of DGC. The DGC inhibition was alleviated by raising the doses of the relevant GAs, suggesting that it is a competitive inhibition. These results and the finding that the growth of normal maize and rice seedlings are inhibited by DGC indicate that GA9, GA19, GA20 or other gibberellins having ring A of the same structure are involved in the growth of these plants as active form(s) or as intermediate(s) leading to the active form(s). 相似文献
11.
[3H]Gibberellin A1 ([3H]GA1)applied to seedlings of dwarf rice (Oryza sativa L. cv. Tanginbozu) was metabolized to GA8. Identification of GA8, was made by gas-liquid radiochromatography using three liquid stationary phases. 相似文献
12.
Noboru Murofushi Takao Yokota Akio Watanabe Nobutaka Takahashi 《Bioscience, biotechnology, and biochemistry》2013,77(5):1101-1113
Four novel gibberellins GA30, GA31, GA33, GA34, five known gibberellins GA8, GA17 (free acid and its monomethyl ester), GA19, GA27, GA29 and the gibberellin-like substances were isolated from immature seeds of evening-glory (Calonyction aculeatum). The structures of GA30, GA31, GA33 and GA34 were elucidated as IX, XVIII, XXII and XXXIV, respectively. The three gibberellin-like substances were partially characterized. 相似文献
13.
The native gibberellin A4 (GA4) was fed as [1, 2-3H]GA4 (1.3 Ci/mmol) to anise somatic cultures maintained either at a proembryo-like stage with 2,4-dichlorophenoxyacetic acid (2,4-D), or allowed to undergo embryogenic development on a - 2,4-D medium. Proembryos, although only 20% of the dry wt of embryos, absorbed 1.4-times more [3H]GA4/g dry wt than embryos. The [3H]GA4 was metabolized to GA1 and GA8, and at least six conjugates [GA4-glucoside (GA4-G), GA4 glucosyl ester (GA4-GE), GA1-0(3)-G, GA1-0(13)-G, GA1-GE and a GA8-glucosyl conjugate]. The major metabolite was GA4-G at each of two, 204 and 348 hr harvests (56–71 %), with GA8-G increasing from < 1 % to 13 % with harvest time. The percentage and amount of GA4-GE was highest at 204 hr (2% and 8 %, for embryos and proembryos, respectively), dropping to < 1 % at 348 hr, thereby indicating hydrolysis (e.g. reversible conjugation). Embryos had reduced amounts and percentages of biologically active GA4 and GA1, and most of their conjugates, but increased amounts and percentages of GA8 and its conjugate(s). This finding is consistent with the hypothesis (based on present and past work) that high levels of biologically active GAs, especially GA1, inhibit somatic embryogenesis in anise and carrot. The auxin, 2,4-D, may thus derive, at least in part, its ability to maintain the proembryo-like stage by inhibiting oxidative metabolism and conjugation of biologically active GAs. 相似文献
14.
S.T. Hoffstein R.M. Manzi K.A. Razgaitis P.E. Bender J. Gleason 《Prostaglandins & other lipid mediators》1986,31(2)
LTB4 (5s, 12R dihdroxy-6, 14-CIS-8, 10-trans-eicosatetraenoic acid) formed in activated neutrophils by lipoxygenation of arachidonic acid is an extremely potent chemotaxin. We examined structural requirements for chemotactic and aggregatory activity of the ligand using synthetic LTB4 and several of its isomers. Additionally we examined the potency of two analogs, nor- and homo- LTB4. Dose response curves for neutrophil chemotaxis to these compounds were obtained using a modified Boyden chamber. The mean distance cells moved into the filter was determined after 30 minutes. Peak chemotactic activity of LTB4 was at 10−7M. At higher concentrations, chemotactic activity was decreased. The shape of the dose response curve was similar to that of FMLP except that maximum chemotaxis to LTB4 was consistently greater than chemotaxis to FMLP. A mixture of the two epimers at C-5 and c-12 shifted the response curve to the right but did not lower maximum activity. Increasing or decreasing the chain by one carbon between the first hydroxyl group and the carboxyl group also shifted the response curve to the right without lowering maximal activity. Changing the 6 double bond from cis to trans has a greater effect. Activity was only detectable at high concentrations and maximum activity achieved was less than 50% that of LTB4. Thus the chain length between the carboxyl and C-5 hydroxyl groups, the c-5 and c-12 absolute stereochemistry and the stereochemistry of the delta6 double bond are all important structural features for chemotactic activity with delta6 stereochemistry apparently having the greatest contribution. The relative potencies of these compounds in inducing aggregation were comparable to their chemotactic potencies. The data suggested that they acted at the same receptor since even the less active isomers were able to desensitive the neutrophils to LTB4. 相似文献
15.
The application of gibberellin A4/7 (GA4/7) to the stem of previous-year (1-year-old) terminal shoots of Scots pine (Pinus sylvestris) seedlings has been observed to stimulate cambial growth locally, as well as at a distance in the distal current-year terminal shoot, but the distribution and metabolic fate of the applied GA4/7, as well as the pathway of endogenous GA biosynthesis in this species, has not been investigated. As a first step, we analysed for endogenous GAs and monitored the transport and metabolism of labelled GAs 4, 9 and 20. Endogenous GAs from the elongating current-year terminal shoot of 2-year-old seedlings were purified by column chromatography and high-performance liquid chromatography and analysed by combined gas chromatography-mass spectrometry (GC-MS). GAs 1, 3, 4, 9, 12 and 20 were identified in the stem, and GAs 1, 3 and 4 in the needles, by full-scan mass spectrometry (GAs 1, 3, 4, 9 and 12) or selected-ion monitoring (GA20) and Kovats retention index. Tritiated and deuterated GA4, GA9 or GA20 were applied around the circumference at the midpoint of the previous-year terminal shoot, and metabolites were extracted from the elongating current-year terminal shoot, the application point, and the 1-year-old needles and the cambial region above and below the application point. After purification, detection by liquid scintillation spectrometry and analysis by GC-MS, it was evident that, for each applied GA, unmetabolised [2H2]GA and [3H]radioactivity were present in every seedling part analysed. Most of the radioactivity was retained at the application point when [3H]GA9 and [3H]GA20 were applied, whereas the largest percentage of radioactivity derived from [3H]GA4 was recovered in the current-year terminal shoot. It was also found that [2H2]GA9 was converted to [2H2]GA20 and to both [2H2]GA4 and [2H2]GA1, [2H2]GA4 was metabolised to [2H2]GA1, and [2H2]GA20 was converted to [2H2]GA29. The data indicate that for Pinus sylvestris shoots (1) GAs applied laterally to the outside of the vascular system of previous-year shoots not only are absorbed and translocated extensively throughout the previous-year and current-year shoots, but also are readily metabolised, (2) the GA metabolic pathways found are closely related to the endogenous GAs identified, and (3) GA9 metabolism follows two distinctly different routes: in one, GA9 is converted to GA1 through GA4, and in the other it is converted to GA20, which is then metabolised to GA29. The results suggest that the late 13-hydroxylation pathway is an important route for GA biosynthesis in shoots of Pinus sylvestris, and that the stimulation of cambial growth in Scots pine by exogenous GA4/7 may be due to its conversion to GA1, rather than to it being active per se. 相似文献
16.
Sang-Mo Kang Abdul Latif Khan Muhammad Hamayun Javid Hussain Gil-Jae Joo Young-Hyun You Jong-Guk Kim In-Jung Lee 《Journal of microbiology (Seoul, Korea)》2012,50(6):902-909
Plant growth-promoting rhizobacteria (PGPR) producing gibberellins (GAs) can be beneficial to plant growth and development. In the present study, we isolated and screened a new strain of Promicromonospora sp., SE188, isolated from soil. Promicromonospora sp. SE188 secreted GAs into its growth medium and exhibited phosphate solubilization potential. The PGPR produced physiologically active (GA1 and GA4) and inactive (GA9, GA12, GA19, GA20, GA24, GA34, and GA53) GAs in various quantities detected by GC/MS-SIM. Solanum lycopersicum (tomato) plants inoculated with Promicromonospora sp. SE188 showed a significantly higher shoot length and biomass as compared to controls where PGPR-free nutrient broth (NB) and distilled water (DW) were applied to plants. The presence of Promicromonospora sp. SE188 significantly up-regulated the non C-13 hydroxylation GA biosynthesis pathway (GA12→GA24→GA9→GA4→ GA34) in the tomato plants as compared to the NB and DW control plants. Abscisic acid, a plant stress hormone, was significantly down-regulated in the presence of Promicromonospora sp. SE188. Contrarily, salicylic acid was significantly higher in the tomato plant after Promicromonospora sp. SE188 inoculation as compared to the controls. Promicromonospora sp. SE188 showed promising stimulation of tomato plant growth. From the results it appears that Promicromonospora sp. SE188 has potential as a bio-fertilizer and should be more broadly tested in field trials for higher crop production in eco-friendly farming systems. 相似文献
17.
Gibberellins (GAs) are a group of diterpenoid plant hormones that control plant growth and development at various stages. Biologically active GAs share the common structures of a 3β-hydroxy group, a carboxy group at C-6, and a γ-lactone between C-4 and C-10. Hydroxylation at C-2β is a major deactivation step in many plant species, and hydroxylation at C-13 has been shown to weaken the binding affinity of GAs to their receptor proteins. In rice, bioactive GA4 has also been shown to be deactivated through 16α,17-epoxidation. Moreover, 16,17-dihydro-16α,17-dihydroxy GA4 has been identified as an aglycon of its glucoside from rice. However, our knowledge on the biological activity of 16,17-epoxidized GAs is currently limited to 16,17-dihydro-16α,17-epoxy GA4. Moreover, the bioactivity of 16,17-dihydro-16α,17-dihydroxy GA4 remains unknown. Here, we synthesized 16,17-epoxidized or dihydroxylated GA derivatives and performed a structure–activity relationship study using rice seedlings. 16,17-Epoxidation of bioactive GA1 and GA4 reduced their activity to promote elongation of rice leaf sheaths. Moreover, 16,17-dihydroxylation significantly decreased the activities of 16,17-dihydro-16α,17-epoxy GAs. These results suggest that GAs are deactivated in a stepwise manner via 16,17-epoxidation and hydrolysis of these epoxy groups. 相似文献
18.
When applied to spurs of mature Prunus avium before floral initiation, gibberellins GA1, GA4 and GA3 inhibited floral initiation by 9–17%, GA7 by 43%, GA3 by 65–71% and 2,2-dimethyl GA4 by 78%. GA9 and GA20 were inactive. Thus activity only of the GAs with a C-3 hydroxyl was increased markedly by a double bond in the C-1,2 or C-2,3 position, and activity increased with increasing hydroxylation. None of the GAs affected the total number of buds (vegetative and floral) surviving in the spur. Measured by the threshold dose required for activity, seedling shoot growth responses to GA3, GA7, GA1 or GA4 resembled those of floral initiation, but di-methylation of GA4 at C-2 had no effect, and GA9 was as active as GA7. Mature shoots, including those on rooted cuttings, were less responsive to GA treatment than were juvenile shoots, with terminal shoots on mature trees more responsive than spur shoots. Spur shoot growth on mature trees responded to GA3 and to a lesser extent GA7, but not to GA1 or GA4. However, all these GAs promoted the growth of terminal shoots on mature trees to similar extents, whereas 2,2-dimethyl GA4 was less active than GA4 The differences between juvenile and mature shoot growth in sensitivity to a C-1,2 or C-2,3 double bond, and between mature shoot growth and floral initiation in GA-structure requirements, indicate that phase change alters the GA complement and/or GA receptor/transduction mechanisms of P. avium. The difference in sensitivity to 2,2-dimethyl GA4 indicates that floral initiation and growth have different requirements for GA transport and/or action. 相似文献
19.
Lack of effect of photoperiod on metabolism of exogenous GA19 and GA1 in Salix pentandra seedlings 总被引:1,自引:0,他引:1
The effect of photoperiod on metabolism of 16,17-[3H2]GA19, and 1.2-[3H2]GA1 applied to intact seedlings of Salix pentandra, was investigated. No difference was found in conversion of 16,17-[3H2]GA19 to 16,17-[3H2]GA20, and 16,17-[3H2]GA1, or in metabolism of 1,2-[3H2]GA1 to [3H]GA8 between plants grown in continuous light and plants exposed for 14 days to a 12-h photoperiod. Also, leaf discs from plants grown in long or short days, converted 16,17-[3H2]GA19 both in light and darkness. These data on metabolism of 16,17-[3H2]GA19, contrast with previous results, which have indicated a photoperiodic control of the metabolism of GA19 to GA20 in S. pentandra. Presence of these applied labelled GAs and their metabolites in different parts of seedlings was recorded, after application to intact seedlings as well as to isolated plant parts. When 16,17-[3H2]GA19 was applied through the roots of intact plants, the relative amounts of 16,17-[3H2]GA1 present in leaves and shoot apices were higher than in roots and stems. In corresponding experiments with 1,2-[3H2]GA1, relatively higher amounts of [3H2]GA8 were found in roots and stems than in leaves and shoot apices. Twenty-four hours after application of 16,17-[3H2]GA19 to isolated plant parts, 16,17-[3H2]GA20 and 16,17-[3H2]GA1 were found in leaves and roots, but not in internodes. Incubation of isolated plant parts with 1,2-[3H2]GA1 for 24 h resulted in presence of [3H]GA8 in all parts. The results mentioned above were obtained by monitoring metabolites by HPLC with on-line radio counting. The conversions of 17-[2H2]GA19 to 17-[2H2]GA20 and 17-[2H2]GA1 in shoot apices and whole seedlings, and of 17-[2H2]GA8 in whole seedlings, were confirmed by GC-MS. 相似文献
20.
Identification of Endogenous Gibberellins in the Winter Annual Weed Thlaspi arvense L 总被引:1,自引:1,他引:0
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Eleven endogenous gibberellins (GAs) were identified by combined gas chromatography-mass spectrometry in purified extracts from shoots of field pennycress (Thlaspi arvense L.): GA1,9,12,15,19,20,24,29,44,51,53. Traces of GA8 and GA25 were tentatively indicated by combined gas chromatography-mass spectrometry-selected ion monitoring. Comparison of the total ion current traces indicated that GA19 and GA44 were most abundant, while GA12,15,20,24,29,53 occurred in lesser amounts. Only small amounts of GA1,9,51 were present. The levels of GA8 and GA25 were barely detectable. Consideration of hydroxylation patterns of the ent-gibberellane ring structure indicates two families of GAs: one with a C-13 hydroxyl group (GA1,8,19,20,29,44,53) and another whose members are either nonhydroxylated (GA9,12,15,24,25) or lack a C-13 hydroxyl group (GA51). This suggests that in field pennycress there are two parallel pathways for GA metabolism with an early branch point from GA12: an early C-13 hydroxylation pathway, leading ultimately to GA1 and GA8 and a C-13 deoxy pathway culminating in the formation of GA9 and GA51. 相似文献