This study evaluated the effect of the structural color phenomenon in resin composites (RCs) on the color adjustment of restorations by investgating their color reproduction performance in human ...incisors of various shade. Cervical cavities were filled with a single-shade RC with 260 nm spherical fillers (Omnichroma (OMN)), conventional A2-shade RCs (Estelite Σ Quick or Clearfil AP-X), or experimental RCs with 5–50 nm fumed silica fillers (R1) and 100 nm spherical fillers (R2). Color parameters (L*C*h*) were measured using a CIE XYZ camera along the centerline of the restorations, and the color difference (∆E00) between corresponding areas of intact and restored teeth was calculated. Additionally, the reflectance spectra of OMN, R1, and R2 were investigated. OMN exhibited significantly lower ∆E00 than other tested RCs (p<0.05) and its reflection spectrum ranged from blue to red, while a blue peak was observed with R1 and R2, indicating a higher color adjustment potential of OMN.
The effect of curing mode of dual-cure resin cements on the tensile bond strength (TBS) of universal adhesives to enamel, dentin, zirconia, lithium disilicate ceramics (LDS), feldspathic porcelain ...(FP), and a Pd-Au alloy was evaluated. The substrates were bonded using Tokuyama Universal Bond (TUB) or Scotchbond Universal Adhesive (SBU), followed by luting with Estecem II (ECII) or Rely-X Ultimate (RXU), respectively, which were used either in light-curing or self-curing mode. The TBS test was performed after 24 h or 5,000 thermal cycles. Light-curing significantly improved the 24-h TBS of TUB/ECII to enamel, dentin and FP, as well as the TBS of SBU/RXU to all substrates except LDS. After thermal cycling, light-curing significantly increased the TBS of both adhesives/cements to dentin, but significant differences between curing modes were seldom observed for other substrates. This suggested that light-curing is essential for the hydrophilic dentin, but self-curing might be sufficient for other substrates.
Abstract
Plants synthesize gibberellin (GA), a diterpenoid hormone, via ent-kaurenoic acid (KA) oxidation. GA has not been detected in the moss Physcomitrium patens despite its ability to synthesize ...KA. It was recently shown that a KA metabolite, 3OH-KA, was identified as an active regulator of protonema differentiation in P. patens. An inactive KA metabolite, 2OH-KA, was also identified in the moss, as was KA2ox, which is responsible for converting KA to 2OH-KA. In this review, we mainly discuss the GA biosynthetic gene homologs identified and characterized in bryophytes. We show the similarities and differences between the OH-KA control of moss and GA control of flowering plants. We also discuss using recent genomic studies; mosses do not contain KAO, even though other bryophytes do. This absence of KAO in mosses corresponds to the presence of KA2ox, which is absent in other vascular plants. Thus, given that 2OH-KA and 3OH-KA were isolated from ferns and flowering plants, respectively, vascular plants may have evolved from ancestral bryophytes that originally produced 3OH-KA and GA.
The effect of 1-week water storage and subsequent 10,000 thermal cycles on light transmission properties (straight-line transmission (G0), diffusion (DF), the amount of transmitted light (AV)), ...translucency parameter (TP) and refractive index (RI) of four nanofilled flowable composites was examined. The composites included Filtek Supreme Ultra Flowable Restorative (FSU), Estelite Flow Quick (EFQ), Estelite Universal Flow, (EUF), and Clearfil Majesty ES Flow (ESF), all of A3 shade. For composites with lower filler load (FSU, EFQ), water storage increased G0, AV and TP, but subsequent thermocycling decreased them. An opposite tendency was found for DF. Materials with higher filler load (EUF, ESF) were not significantly affected by aging conditions. RI of EFQ and EUF containing bisphenol A polyethoxy methacrylate (Bis-MPEPP) increased significantly after thermocycling. Additionally, morphological changes were observed using scanning electron microscopy which revealed cracks within nanocluster fillers and dislocation of particles in FSU and EFQ after thermocycling.
The effect of long-term water storage on the regional ultimate tensile strength (UTS), water sorption (Wsp) and water solubility (Wsl) of conventional and bulk-fill resin composites at various depths ...was investigated. Composite specimens light-cured from one side were sectioned into beams corresponding to different depths (1–5 mm) and stored in water for 24 h, 1 week, 1 month, 6 months or 1 year. UTS increased during the first week and then gradually decreased over time, especially in deeper regions. Bulk-fill composites initially exhibited similar UTS at all depths, whereas the UTS of conventional composites at 1 mm and 5 mm differed significantly at all time points. Wsp and Wsl increased with depth and storage time, markedly at 3–5 mm after 1 month for conventional composites and after 6 months for bulk-fill composites. The signs of degradation at depths beyond 3 mm suggested that even bulk-fill composites have suboptimal properties in layers more than 3 mm in thickness.
Plant architecture is mostly determined by shoot branching patterns. Apical dominance is a well-known control mechanism in the development of branching patterns, but little is known regarding its ...role in monocots such as rice. Here, we show that the concept of apical dominance can be applied to tiller bud outgrowth of rice. In dwarf10 (d10), an enhanced branching mutant of rice, apical dominance can be observed, but the inhibitory effects of the apical meristem was reduced. D10 is a rice ortholog of MAX4/RMS1/DAD1 that encodes a carotenoid cleavage dioxygenase 8 and is supposed to be involved in the synthesis of an unidentified inhibitor of shoot branching. D10 expression predominantly occurs in vascular cells in most organs. Real-time polymerase chain reaction analysis revealed that accumulation of D10 mRNA is induced by exogenous auxin. Moreover, D10 expression is upregulated in six branching mutants, d3, d10, d14, d17, d27 and high tillering dwarf (htd1). No such effects were found for D3 or HTD1, the MAX2 and MAX3 orthologs, respectively, of rice. These findings imply that D10 transcription might be a critical step in the regulation of the branching inhibitor pathway. In addition, we present observations that suggest that FINE CULM1 (FC1), a rice ortholog of teosinte branched 1 (tb1), possibly works independently of the branching inhibitor pathway.
ABSTRACT
Evaluation of individual roles of plant hormones in fruit development is difficult because various plant hormones function simultaneously. In this study, to analyze the effect of plant ...hormones on fruit maturation one by one, plant hormones were applied to auxin-induced parthenocarpic woodland strawberry (Fragaria vesca) fruits. As a result, auxin, gibberellin (GA), and jasmonate, but, not abscisic acid and ethylene increased the proportion of ultimately mature fruits. So far, to produce comparable fruit with pollinated fruit in size, auxin with GA treatment was required in woodland strawberry. Picrolam (Pic), the most potent auxin in inducing parthenocarpic fruit, induced fruit which is comparable in size with pollinated fruit without GA. The endogenous GA level and the result of the RNA interference analysis of the main GA biosynthetic gene suggest that a basal level of endogenous GA is essential for fruit development. The effect of other plant hormones was also discussed.
Graphical Abstract
Graphical Abstract
Roles of plant hormones during fruit maturation were evaluated in auxin-induced parthenocarpic woodland strawberry fruit.
Gibberellins (GAs) are a large family of tetracyclic, diterpenoid plant hormones that induce a wide range of plant growth responses. It has been postulated that plants have two types of GA receptors, ...including soluble and membrane-bound forms. Recently, it was determined that the rice GIBBERELLIN INSENSITIVE DWARF1 (GID1) gene encodes an unknown protein with similarity to the hormone-sensitive lipases that has high affinity only for biologically active GAs. Moreover, GID1 binds to SLR1, a repressor of GA signaling, in a GA-dependent manner in yeast cells. Based on these observations, it has been concluded that GID1 is a soluble receptor mediating GA signaling in rice. More recently, Arabidopsis thaliana was found to have three GID1 homologs, AtGID1a, b, and c, all of which bind GA and interact with the five Arabidopsis DELLA proteins.
Gibberellins (GAs) are phytohormones essential for many developmental processes in plants. A nuclear GA receptor, GIBBERELLIN INSENSITIVE DWARF1 (GID1), has a primary structure similar to that of the ...hormone-sensitive lipases (HSLs). Here we analyse the crystal structure of Oryza sativa GID1 (OsGID1) bound with GA4 and GA3 at 1.9 Å resolution. The overall structure of both complexes shows an / -hydrolase fold similar to that of HSLs except for an amino-terminal lid. The GA-binding pocket corresponds to the substrate-binding site of HSLs. On the basis of the OsGID1 structure, we mutagenized important residues for GA binding and examined their binding activities. Almost all of them showed very little or no activity, confirming that the residues revealed by structural analysis are important for GA binding. The replacement of Ile 133 with Leu or Val-residues corresponding to those of the lycophyte Selaginella moellendorffii GID1s-caused an increase in the binding affinity for GA34, a 2 -hydroxylated GA4. These observations indicate that GID1 originated from HSL and was further modified to have higher affinity and more strict selectivity for bioactive GAs by adapting the amino acids involved in GA binding in the course of plant evolution.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Ethylene is the only gaseous plant hormone that regulates several aspects of plant growth, from seedling morphogenesis to fruit ripening and organ senescence. Ethylene also stimulates the germination ...of
, a root parasitic weed that severely damages crops in sub-Saharan Africa. Thus, ethylene response stimulants can be used as weed and crop control agents. Ethylene and ethephon, an ethylene-releasing compound, are currently used as ethylene response inducers. However, since ethylene is a gas, which limits its practical application, we targeted the development of a solid ethylene response inducer that could overcome this disadvantage. We performed chemical screening using
"triple response" as an indicator of ethylene response. After screening, we selected a compound with a thiourea skeleton and named it ZKT1. We then synthesized various derivatives of ZKT1 and evaluated their ethylene-like activities in
. Some derivatives showed considerably higher activity than ZKT1, and their activity was comparable to that of 1-aminocyclopropane-1-carboxylate. Mode of action analysis using chemical inhibitors and ethylene signaling mutants revealed that ZKT1 derivatives activate the ethylene signaling pathway through interactions with its upstream components. These thiourea derivatives can potentially be potent crop-controlling chemicals.
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