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Biomedical subjects

Masatoshi Nakajima

Publications and source records attributed to Masatoshi Nakajima.

At least 19 recordsLinked to original sources
PubMed2006

Effect of simulated pulpal pressure on all-in-one adhesive bond strengths to dentine.

OBJECTIVES: To evaluate the durability of all-in-one adhesive systems bonded to dentine with and without simulated hydrostatic pulpal pressure (PP). METHODS: Flat dentine surfaces of extracted human molars were prepared. Two all-in-one adhesive systems, One-Up Bond F (OBF) (Tokuyama Corp., Tokyo, Japan), and Fluoro Bond Shake One (FBS) (Shofu Co., Kyoto, Japan) were applied to the dentine surfaces under either a PP of 0 or 15cm H(2)O. Then, resin composite build-ups were made. The specimens bonded under pressure were stored in 37 degrees C water for 24h, 1 and 3 months under 15cm H(2)O PP. Specimens not bonded under pressure were stored under zero PP. After storage, the specimens were sectioned into slabs that were trimmed to hourglass shapes and subjected to micro-tensile bond testing (muTBS). The data were analysed using two-way ANOVA and Holm-Sidak HSD multiple comparison tests (alpha=0.05). RESULTS: The muTBS of OBF fell significantly (p<0.05) when PP was applied during bonding and storage, regardless of storage time. In contrast, although the muTBS of OBF specimens bonded and stored without hydrostatic pressure storage fell significantly over the 3 months period, the decrease was less than half as much as specimens stored under PP. In FBS bonded specimens, although there was no significant difference between the muTBS with and without hydrostatic pulpal pressure at 24h, by 1 and 3 months of storage under PP, significant reductions were seen compared with the control group without PP. CONCLUSION: The muTBS of OBF bonded specimens was lowered more by simulated PP than by storage time; specimens bonded with FBS were not sensitive to storage time in the absence of PP, but showed lower bond strengths at 1 and 3 months in the presence of PP.

Composite Resins↗
PubMed2006

Identification of a peptide mimic of bioactive gibberellins with affinity to GA 2-oxidase.

Previously we reported the first example of peptide mimics of a small hydrophobic molecule, a phytohormone gibberellin. The second peptide mimic of gibberellin has been identified from random peptide libraries by its affinity to a type of catalyzing enzyme of gibberellins, which specifically recognizes bioactive gibberellins. These results suggest that even hydrophobic compounds can be mimicked by peptides.

Catalysis↗
PubMed2006

Mechanical properties and bond strength of dual-cure resin composites to root canal dentin.

OBJECTIVES: To evaluate the regional mechanical properties of dual-cure resin composites and their regional bond strengths to root canal dentin. METHODS: One of the following dual-cure resin composites was placed in artificial post spaces: Unifil Core (UC), Clearfil DC Core (DC), Build-It FR (BI), Clearfil DC Core-automix (DCA), and photo-cured for 60s. After 24h storage, each specimen was serially sliced to harvest eight hour-glass shaped specimens for measurement of regional ultimate tensile strength (UTS), and the remaining eight semi-circular slabs were polished for the measurement of Knoop Hardness Number (KHN). For the microtensile bond strength (muTBS) test, post cavities were prepared in human premolar roots, and the cavity surfaces treated with Clearfil SE Bond and photo-cured for 10s. The post spaces were then filled with one of the above resin composites and photo-cured for 60s. After 24h storage, each specimen was serially sliced into 8, 0.6x0.6 mm-thick beams for the muTBS test. The data were divided into coronal and apical regions and analyzed using ANOVA and post hoc test (alpha=0.05). RESULTS: UTS and KHN were affected by the type of dual-cure resin composite and region (p<0.0001). There was no relationship between UTS and KHN for each material. The auto-mix type of resin composite possessed superior UTS to that of the hand-mix type. muTBS among the four composite materials were not significantly different at both apical and coronal regions (p>0.05). Regional differences in bond strengths were found for all materials (p<0.05). SIGNIFICANCE: The UTS and KHN of the dual-cure resin composites varied among each material, however, differences in the mechanical properties of the resin core materials did not affect their adhesion to root canal dentin.

Composite Resins↗
PubMed2006

Identification and characterization of Arabidopsis gibberellin receptors.

Three gibberellin (GA) receptor genes (AtGID1a, AtGID1b and AtGID1c), each an ortholog of the rice GA receptor gene (OsGID1), were cloned from Arabidopsis, and the characteristics of their recombinant proteins were examined. The GA-binding activities of the three recombinant proteins were confirmed by an in vitro assay. Biochemical analyses revealed similar ligand selectivity among the recombinants, and all recombinants showed higher affinity to GA(4) than to other GAs. AtGID1b was unique in its binding affinity to GA(4) and in its pH dependence when compared with the other two, by only showing binding in a narrow pH range (pH 6.4-7.5) with 10-fold higher affinity (apparent K(d) for GA(4) = 3 x 10(-8) m) than AtGID1a and AtGID1c. A two-hybrid yeast system only showed in vivo interaction in the presence of GA(4) between each AtGID1 and the Arabidopsis DELLA proteins (AtDELLAs), negative regulators of GA signaling. For this interaction with AtDELLAs, AtGID1b required only one-tenth of the amount of GA(4) that was necessary for interaction between the other AtGID1s and AtDELLAs, reflecting its lower K(d) value. AtDELLA boosted the GA-binding activity of AtGID1 in vitro, which suggests the formation of a complex between AtDELLA and AtGID1-GA that binds AtGID1 to GA more tightly. The expression of each AtGID1 clone in the rice gid1-1 mutant rescued the GA-insensitive dwarf phenotype. These results demonstrate that all three AtGID1s functioned as GA receptors in Arabidopsis.

Amino Acid Sequence↗
PubMed2006

Retrospective study of five-year clinical performance of direct composite restorations using a self-etching primer adhesive system.

This study was conducted to assess the five-year clinical performance of composite restorations using a self-etching primer adhesive system, Clearfil Liner Bond II. Restorations were rated using the following scale: A--Good; B--Clinically acceptable; C--Clinically unacceptable; or D--Already replaced. The ratings were analyzed using Freedman's test (p=0.01) and Steel-Dwass test (p=0.05). A total of 83 restorations from 36 patients were identified from treatment records. Twenty-six restorations (31.3%) presented A rating and 36 restorations (43.4%) were clinically acceptable (B rating), while five (6.0%) received C rating and 16 (19.3%) had already been replaced (D rating). The mean survival rate of serviceable restorations (i.e., combined A and B ratings) after five years was 74.7%. It was found that cavity form, including cavity size, and occlusal contact seemed to influence longevity.

Acid Etching, Dental↗
PubMed2006

Regional bond strengths of a dual-cure resin core material to translucent quartz fiber post.

PURPOSE: To evaluate the microtensile bond strength (muTBS) of a dual-cure resin core material to different regions of translucent quartz fiber post in a post cavity using different surface treatments. METHODS: 30 translucent quartz fiber posts (Light-Post) were used and divided into six groups according to the surface treatments: (1) no surface treatment (Control); (2) photo-cure bonding agent, Clearfil Liner Bond 2V Bond A (PLB); (3) dual-cure bonding agent, Clearfil Liner Bond 2V Bond A+B (DLB); (4) BdA+B followed by light-cured for 20 seconds (DLB & LC); (5) silane coupling bonding agent, Clearfil Photobond with Porcelain Bond Activator (PB+PBA); (6) PB+PBA followed by light-cure for 20 seconds (PB+PBA&LC). Treated post were cemented into artificial post cavities using a dual-cure composite core material (Clearfil DC Core) and light-cured for 60 seconds from the top of the cavity. After 24-hour storage in water, each specimen was serially sliced into twelve 0.6 x 0.6 mm-thick beams for the muTBS test. The data were divided into three regions (upper/middle/bottom) and analyzed using two-way ANOVA and Dunnet's T3 multiple comparisons (alpha = 0.05). RESULTS: The highest bond strength was present in the silane coupling bonding agent group for all regions (P < 0.05). Application of the bonding agent to the post surface significantly improved the bond strength compared with control (P < 0.05). There were no significant differences in muTBS at all regions between the photo and dual-cure type bonding agents (P < 0.05). The bond strength significantly decreased at the bottom region when the post surface was treated with bonding agents (P < 0.05), whereas no regional differences in bond strength were found in the silane coupling bonding agent group (P > 0.05).

Composite Resins↗
PubMed2006

Bonding durability of a self-etching primer system to normal and caries-affected dentin under hydrostatic pulpal pressure in vitro.

PURPOSE: To evaluate the bonding durability of a self-etching primer system to normal and caries-affected dentin under hydrostatic pulpal pressure. METHODS: 18 extracted human molars with occlusal caries were used. Their occlusal dentin surfaces were ground flat to expose normal and caries-affected dentin using #600 SiC paper under running water. Clearfil SE Bond was placed on the dentin surface including the caries-affected dentin according to the manufacturer's instructions and then the crowns were built up with resin composite (Clearfil AP-X) under either a pulpal pressure of 15 cm H2O or none (control). The bonded specimens were stored in 100% humidity for 1 day (control) or for 1 week and 1 month with hydrostatic pulpal pressure. After storage, the specimens were serially sectioned into 0.7 mm-thick slabs and trimmed to an hour-glass shape with a 1 mm2 cross-section, isolated by normal or caries-affected dentin, and then subjected to the micro-tensile bond test. Data were analyzed by two-way ANOVA and Tukey's test (P< 0.05). RESULTS: Hydrostatic pulpal pressure significantly reduced the bond strength to normal dentin after 1-month storage (P< 0.05), but did not affect the bond strength to caries-affected dentin.

Analysis of Variance↗
PubMed2005

Effect of prolonged photo-irradiation time of three self-etch systems on the bonding to root canal dentine.

OBJECTIVES: To evaluate the effect of photo-irradiation time to the adhesive on the regional bond strength of a dual-cure resin core material to root canal dentine using photo and dual-cure adhesives with self-etching primer. MATERIALS AND METHODS: Post spaces were prepared in extracted premolars and then the root canal dentine was treated with one of the following bonding procedures: (1) Clearfil SE Bond Primer/Bond (SE), (2) Nano-Bond Primer/Photo-cure adhesive (PNB), (3) Nano-Bond Primer/Dual-cure adhesive (DNB). Photo-irradiation was performed for 10 or 20s from a coronal direction. The post spaces were then filled with a dual-cure composite resin (Build-It FR) and light-cured for 60s. After 24h storage, each specimen was serially sliced into 8, 0.6 x 0.6mm-thick beams for the microTBS test. The bond strength data were divided into coronal and apical regions and analysed using three-way ANOVA and Games-Howell multiple comparison (alpha=0.05). RESULTS: The microTBS of the photo-cure adhesive resin, SE and PNB, significantly decreased (p<0.05) at the apical region when the photo-irradiation time was 10s. However, the bond strength of the SE group was significantly improved at both regions when photo-irradiation time was extended to 20s (p<0.05). There were no differences in microTBS of the photo-cure adhesive resin (PNB) cured for 20s and dual-cure adhesive resin (DNB) (p>0.05). CONCLUSION: Photo-cure adhesive was effective for application on root canal dentine when the photo-irradiation time was sufficient. Extension of photo-irradiation time to the adhesive improved the bond strength depending on the type of adhesive resin.

Adhesiveness↗
PubMed2005

Microtensile bond strength of a filled vs unfilled adhesive to dentin using self-etch and total-etch technique.

OBJECTIVE: The purpose of this study was to evaluate the effect of a filled adhesive (One-Step Plus; Bisco) versus an unfilled adhesive (One-Step; Bisco) on the microtensile bond strength (muTBS) to dentin using total-etch (Uni-etch; Bisco) and self-etch (Tyrian SPE; Bisco) techniques. METHODS: Twenty extracted human third molars were ground flat to expose occlusal dentin. After the dentin surfaces were polished with 600-grit SiC paper, the teeth were randomly assigned to four groups according to the bonding agent and technique being used. Dentin surfaces were bonded with One-Step Plus+total-etch; One-Step Plus+self-etch; One-Step+total-etch and One-Step+self-etch. Composite buildups were performed with Clearfil AP-X (Kuraray Medical). Following storage in distilled water at 37 degrees C for 24 h, the bonded specimens were serially sectioned into 0.7 mm-thick slabs and then trimmed to hour-glass shapes with a 1 mm2 cross-sectional area (n=20). Microtensile bond strengths were determined using the EZ-test (Shimadzu) at a cross-head speed of 1 mm/min. Data were analyzed using two-way ANOVA and Tukey's post hoc test. RESULTS: There were no significant differences in the muTBS between One-Step Plus and One-Step adhesives when they were used with the total-etch and self-etch techniques (p>0.05). However with the total-etch technique both adhesives yielded significantly higher bond strength values than the self-etch technique (p<0.001). CONCLUSION: The filled adhesive One-Step Plus did not show any beneficial effect than the unfilled adhesive One-Step on the muTBS to dentin with total-etch and self-etch techniques. Irrespective from the adhesive type, self-etch technique revealed lower bond strengths than the total-etch technique.

Adhesives↗
PubMed2005

GIBBERELLIN INSENSITIVE DWARF1 encodes a soluble receptor for gibberellin.

Gibberellins (GAs) are phytohormones that are essential for many developmental processes in plants. It has been postulated that plants have both membrane-bound and soluble GA receptors; however, no GA receptors have yet been identified. Here we report the isolation and characterization of a new GA-insensitive dwarf mutant of rice, gid1. The GID1 gene encodes an unknown protein with similarity to the hormone-sensitive lipases, and we observed preferential localization of a GID1-green fluorescent protein (GFP) signal in nuclei. Recombinant glutathione S-transferase (GST)-GID1 had a high affinity only for biologically active GAs, whereas mutated GST-GID1 corresponding to three gid1 alleles had no GA-binding affinity. The dissociation constant for GA4 was estimated to be around 10(-7) M, enough to account for the GA dependency of shoot elongation. Moreover, GID1 bound to SLR1, a rice DELLA protein, in a GA-dependent manner in yeast cells. GID1 overexpression resulted in a GA-hypersensitive phenotype. Together, our results indicate that GID1 is a soluble receptor mediating GA signalling in rice.

Amino Acid Sequence↗
PubMed2005

Contribution of gibberellins to the formation of Arabidopsis seed coat through starch degradation.

To clarify the role of gibberellins in the seed development of Arabidopsis, we investigated the sites where gibberellins are synthesized and induce alpha-amylase genes. The spatial and temporal expression of the genes encoding gibberellin biosynthetic enzymes and alpha-amylases was examined by reverse transcription-PCR (RT-PCR) and in situ hybridization. The mRNAs of AtGA20ox2, AtGA20ox3 and AtGA3ox4 began to be detectable 5-7 d after pollination. In situ hybridization showed that these genes were expressed almost simultaneously around starch granules in the outer integument, preceding the disappearance of those granules. AtGA20ox2 and AtGA3ox4 but not AtGA20ox3 also showed their signals at the rim of the developing embryo. The alpha-amylase gene, Amy3, which responded to gibberellin, was mainly expressed in the developing seed, spatially overlapping with the expression of AtGA20ox2 and AtGA3ox4. These results suggest that gibberellins function in at least two sites of the seed: the outer integument and part of the embryo. We examined the phenotypes of a T-DNA insertion line of AtGA3ox4 and observed the following: (i) a decrease of alpha-amylase gene transcripts in young siliques; (ii) delay of starch degradation in the outer integument; (iii) disarrangement of the seed surface structure; and (iv) abnormal swelling pattern of polysaccharides after imbibition by the mature seed. These characteristics are phenotypes of plants under gibberellin starvation, because the abnormalities could be almost overcome with applied gibberellin, and the gibberellin-treated mutant was indistinguishable from the wild type. These results strongly suggest that gibberellins in the outer integument would be required for the normal formation of the Arabidopsis seed coat.

Arabidopsis↗
PubMed2005

Wnt5b partially inhibits canonical Wnt/beta-catenin signaling pathway and promotes adipogenesis in 3T3-L1 preadipocytes.

To elucidate the functional roles of Wnt5b in adipogenesis, we characterized gene expression profiles in Wnt5b overexpressing 3T3-L1 cells using microarray analysis. Of the approximately 20,000 genes screened, we found that 85 genes were up-regulated and 211 genes were down-regulated in 3T3-L1 cells overexpressing Wnt5b. Among the genes regulated by Wnt5b, the expressions of insulin like growth factor-1 (IGF-1), vascular endothelial growth factor-C (VEGF-C), and WNT1 inducible signaling pathway protein 1 (WISP-1), which were known to be up-regulated by Wnt1/beta-catenin signaling, were decreased in the Wnt5b overexpressing cells. This result was subsequently confirmed by real-time quantitative RT-PCR (IGF-1; 0.74+/-0.08 and 0.56+/-0.08, WISP-1; 0.71+/-0.03 and 0.56+/-0.08, and VEGF-C; 0.67+/-0.01 and 0.80+/-0.07, mean+/-SEM, compared with the control at zero and two days after induction of differentiation, respectively). We also found that Wnt5b overexpression in 3T3-L1 preadipocytes was able to partially prevent the inhibitory effect of Wnt3a on adipogenesis. Furthermore, the overexpression of Wnt5b was able to inhibit Wnt3a-induced activation of the canonical Wnt/beta-catenin pathway as evidenced by the reduced translocation of beta-catenin into the nucleus. These findings indicate that Wnt5b may promote adipogenesis in 3T3-L1 cells, at least in part, by antagonizing the canonical Wnt/beta-catenin pathway.

3T3-L1 Cells↗
PubMed2005

Elemental distributions and microtensile bond strength of the adhesive interface to normal and caries-affected dentin.

The aim of this study was to evaluate the microtensile bond strength (microTBS) and the elemental contents of the adhesive interface created to normal versus caries-affected dentin. Extracted human molars with coronal carious lesions were used in this study. A self-etching primer/adhesive system (Clearfil Protect Bond) was applied to flat dentin surfaces with normal and caries-affected dentin according to the manufacturer's instructions. After 24 h water storage, the bonded specimens were cross-sectioned and subjected to a microTBS test and electron probe microanalysis for the elemental distributions [calcium (Ca), phosphorus (P), magnesium (Mg), and nitrogen (N)] of the resin-dentin interface after gold sputter-coating. The microTBS to caries-affected dentin was lower than that of normal dentin. The demineralized zone of the caries-affected dentin-resin interface was thicker than that of normal dentin (approximately 3 microm thick in normal dentin; 8 microm thick in caries-affected dentin), and Ca and P in both types of dentin gradually increased from the interface to the underlying dentin. The caries-affected dentin had lost most of its Mg content. The distributions of the minerals, Ca, P, and Mg, at the adhesive interface to caries-affected dentin were different from normal dentin. Moreover, a N peak, which was considered to be the collagen-rich zone resulting from incomplete resin infiltration of exposed collagen, was observed to be thicker within the demineralized zone of caries-affected dentin compared with normal dentin.

Dental Caries↗
PubMed2005

Effect of acidic pretreatment combined with a silane coupling agent on bonding durability to silicon oxide ceramic.

This study examined the effect of different acidic treatments and the role of a phosphate monomer in a silane coupling agent on the durability of the dual-cure resin cement/silicon oxide bond. Ceramic blocks (Vita Celay Blanks) were cut into multiple 3 mm-thick slices and polished using 600 grit SiC paper. Two pairs were left untreated [controls (CTRL)], two pairs were treated with 40% phosphoric acid and rinsed with water for 30 s (PA), and another two pairs treated with 20% hydrofluoric acid followed by 30 s water rinsing (HF). Half the specimens were silanated with Tokuso Ceramics Primer (TCP) (Tokuyama) and the other half with TCP formulated without phosphate monomer (TCP-NoPM). All the pairs were bonded with Bistite II dual-cure resin cement (Tokuyama) and light cured. After 24 h water storage at 37 degrees C, 0.7 mm-thick slabs were serially sectioned. Immediately, after 6 months and after 1 year of water storage, two slabs were randomly selected from each subgroup, and sliced into beams (6 x 0.7 x 0.7 mm) for the microtensile bond strength (muTBS) test. The muTBS data were statistically analyzed using multiple Wilcoxon Signed Rank tests (p < 0.05). Failure modes were determined using a confocal laser-scanning microscope. Ceramic surface morphology after the different acidic treatments was examined using an SEM. After 1 day, in the case of silane treatment with TCP, there were no significant differences in muTBS between the control and acid-treated groups (p > 0.05), whereas with TCP-NoPM, the muTBS of the control was significantly lower than the acid-treated groups (p < 0.05). All the TCP and acid-treated TCP-NoPM groups exhibited significant reductions in muTBS after 6 months (p < 0.05). After 1 year, the muTBS of the acid-treated TCP groups were not significantly different from the control TCP group (p > 0.05). There was also no significant difference between the HF-treated TCP and TCP-NoPM groups (p > 0.05) after 1 year, all exhibiting greater than 10 MPa tensile bond strength. It is suggested that acidic pretreatment of the ceramic surface does not improve the durability of the dual-cure resin cement/silicon oxide ceramic bond when an acidic phosphate monomer is present as an activator in a ceramic primer.

Acid Etching, Dental↗
PubMed2005

Gibberellin 2-oxidases from seedlings of adzuki bean (Vigna angularis) show high gibberellin-binding activity in the presence of 2-oxoglutarate and Co2+.

Five full-length cDNA encoding gibberellin 2-oxidases, VaGA2oxA1, VaGA2oxA2, VaGA2oxB1, VaGA2oxB2, and VaGA2oxB3, were cloned from etiolated adzuki bean (Vigna angularis cv. Dainagon) seedlings, and their enzymatic characteristics were examined using recombinant enzymes fused with glutathione S-transferase (GST). Recombinant VaGA2oxA1 (rVaGA2oxA1) and rVaGA2oxA2 showed 2beta-hydroxylation activity by converting GA1, GA4, GA9, GA20, GA4-methyl ester, and 16,17-dihydro-GA4 to the corresponding 2beta-hydroxylated gibberellins, which were identified by GC/MS. rVaGA2oxB1, rVaGA2oxB2, and rVaGA2oxB3 showed similar activity by converting [3H4]-16,17-dihydro-GA4 to a metabolite showing an Rf value of 16,17-dihydro-GA34. RNA-blot analysis showed that VaGA2oxA1 and VaGA2oxA2 were the major ones expressed in etiolated hypocotyls. The addition of Co2+ instead of Fe2+ to the assay medium apparently reduced the enzymatic activity, but increased the binding of [3H4]-16,17-dihydro-GA4 to rVaGA2oxA1, indicating the possibility that VaGA2oxs can be detected as gibberellin-binding proteins under certain conditions.

Amino Acid Sequence↗
PubMed2005

Similarities and differences between the characteristics of gibberellin-binding protein and gibberellin 2-oxidases in adzuki bean (Vigna angularis) seedlings.

Gibberellin-binding proteins (GBPs) were purified ca. 230,000 fold. The characteristics of adzuki GBP were examined and compared with those of a recombinant gibberellin 2-oxidase (rVaGA2oxA1) that was fused with glutathione S-transferase (GST). VaGA2oxA1 was most abundantly expressed in etiolated adzuki bean seedlings, and VaGA2oxA1 and GBPs from adzuki bean seedlings showed gibberellin-binding activity when incubated with 2-oxoglutarate and Co2+. Both rVaGA2oxA1 and partially purified GBPs from adzuki bean seedlings showed very similar selectivity to gibberellins in binding assays, where biologically active gibberellins such as GA4, GA3, GA7, and GA1 showed higher binding affinity than biologically inactive gibberellins such as GA8, GA34, and 3-epi-GA4. The polyclonal antibody raised against rVaGA2oxA1 cross-reacted with all rVaGA2oxs (rVaGA2oxA1, rVaGA2oxA2, rVaGA2oxB1, rVaGA2oxB2, and rVaGA2oxB3) whose cDNAs were cloned from adzuki bean seedlings. Treated with the antibody, the recombinants that originally showed gibberellin-binding activity lost both binding activity and enzymatic activity. In contrast to the recombinants, the gibberellin-binding activity of GBPs from adzuki bean seedlings was hardly affected by the antibody treatment. The GBPs showed very weak gibberellin 2-oxidase-like activity, and it was not affected by the antibody treatment either. These observations suggest that a major component that showed GA-binding activity was apparently different from any gibberellin 2-oxidase cloned from the seedlings.

Carrier Proteins↗
PubMed2005

Distribution of gibberellins and expressional analysis of GA 20-oxidase genes of morning glory during fruit maturation.

Gibberellins A1/3 (GA1/3) and GA20 appeared earlier in surrounding tissues (pericarps/carpel/placenta) than in developing seeds of morning glory. The content of GA1/3 became higher in seeds than in the surrounding tissues at 9 days after anthesis (DAA), while that of GA20 stayed lower in seeds even at 12 DAA, suggesting the possibility that GA20 was translocated into seeds from the surrounding tissues and converted to GA1/3. The site of biosynthesis of GA20 in the fruits was determined by RNA-blotting and in situ hybridization of GA 20-oxidase genes (InGA20ox1, InGA20ox2). InGA20ox1 was not expressed in the surrounding tissues but in seeds, while no signal due to InGA20ox2 was detected in neither tissue. The expression of InGA20ox1 started in the seed coat near the hilum and spread in the seed coat like those of GA 3-oxidase and GA-inducible alpha-amylase genes. These observations suggest that GA biosynthesis is tissue-specifically and time-dependently regulated in the fruit of morning glory.

Fruit↗