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Four new quinoxaline-spanned cavitands having a diester hydrogen phosphate group were successfully synthesised. These phosphorous derivatives were applied in Bronsted acid-assisted catalytic conjugate addition reactions. The resul...
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Four new quinoxaline-spanned cavitands having a diester hydrogen phosphate group were successfully synthesised. These phosphorous derivatives were applied in Bronsted acid-assisted catalytic conjugate addition reactions. The results were ranked with the control of diphenyl hydrogen phosphate as well as among those four cavitands. The structure-activity relationship revealed that the catalyst centre surrounded by two trans-positioned quinoxalines significantly influences reaction profile and product distribution. This comparative study provides us an intellectual basis for future catalytic cavitand chemistry and artificial enzymatic catalysis.
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Colletotrichum orbiculare, an anthracnose disease fungus of cucurbit plants, extends penetration hyphae inside the epidermal cells of host plants. Unlike vegetative hyphae formed on a nutrient rich medium, this pathogen initially ...
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Colletotrichum orbiculare, an anthracnose disease fungus of cucurbit plants, extends penetration hyphae inside the epidermal cells of host plants. Unlike vegetative hyphae formed on a nutrient rich medium, this pathogen initially develops biotrophic penetration hyphae, which acquire nutrient resources from living host cells and secret effector proteins to suppress host defense responses. Subsequently, the nature of penetration hyphae changes from biotrophy to necrotrophy in response to the interaction with a host plant. Hence, controlling the extension of penetration hyphae is crucial for C. orbiculare infection. Here, we identified CoGRIM19 encoding Nadh-ubiquinone oxidoreductase subunit as a pathogenicity gene. Pathogenicity assays showed that the cogrim19 mutant caused no visible symptoms on cucumber cotyledons. Microscopic observations revealed that the cogrim19 mutant developed an appressorium and penetration hyphae under artificial conditions such as on coverslips or cellulose membranes, but the penetration hyphae of the mutant were retarded in the cucumber cotyledons. Microscopic observations of biotrophy-specific expression fluorescent signals revealed that the biotrophic stage was maintained in the retarded penetration hyphae of the cogrim19 mutant as the penetration of the wild type. In addition to cytological observations, pathogenicity assays using wounded leaves showed that the cogrim19 mutant had an attenuated pathogenesis. Taking our results together, CoGRIM19 is required for invasive hyphal growth inside the epidermal cells of cucumber cotyledons in C. orbiculare.
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The unfolded protein response (UPR) or the endoplasmic reticulum (ER) stress response is a homeostatic cellular response conserved in eukaryotes to alleviate the accumulation of unfolded proteins in the ER. In the present study, w...
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The unfolded protein response (UPR) or the endoplasmic reticulum (ER) stress response is a homeostatic cellular response conserved in eukaryotes to alleviate the accumulation of unfolded proteins in the ER. In the present study, we characterized the UPR in the liverwort Marchantia polymorpha to obtain insights into the conservation and divergence of the UPR in the land plants. We demonstrate that the most conserved UPR transducer in eukaryotes, IRE1, is conserved in M. polymorpha, which harbors a single gene encoding IRE1. We showed that MpIRE1 mediates cytoplasmic splicing of mRNA encoding MpbZIP7, a M. polymorpha homolog of bZIP60 in flowering plants, and upregulation of ER chaperone genes in response to the ER stress inducer tunicamycin. We further showed that MpIRE1 also mediates downregulation of genes encoding secretory and membrane proteins in response to ER stress, indicating the conservation of regulated IRE1-dependent decay of mRNA. Consistent with their roles in the UPR, Mpire1ge and Mpbzip7ge mutants exhibited higher sensitivity to ER stress. Furthermore, an Mpire1ge mutant also exhibited retarded growth even without ER stress inducers, indicating the importance of MpIRE1 for vegetative growth in addition to alleviation of ER stress. The present study provides insights into the evolution of the UPR in land plants.
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How genetic variations affect gene expression dynamics of field-grown plants remains unclear. Expression quantitative trait loci (eQTL) analysis is frequently used to find genomic regions underlying gene expression polymorphisms. ...
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How genetic variations affect gene expression dynamics of field-grown plants remains unclear. Expression quantitative trait loci (eQTL) analysis is frequently used to find genomic regions underlying gene expression polymorphisms. This approach requires transcriptome data for the complete set of the QTL mapping population under the given conditions. Therefore, only a limited range of environmental conditions is covered by a conventional eQTL analysis. We sampled sparse time series of field-grown rice from chromosome segment substitution lines (CSSLs) and conducted RNA sequencing (RNA-Seq). Then, by using statistical analysis integrating meteorological data and the RNA-Seq data, we identified 1,675 eQTLs leading to polymorphisms in expression dynamics under field conditions. A genomic region on chromosome 11 influences the expression of several defense-related genes in a time-of-day- and scaled-age-dependent manner. This includes the eQTLs that possibly influence the time-of-day- and scaled-age-dependent differences in the innate immunity between Koshihikari and Takanari. Based on the eQTL and meteorological data, we successfully predicted gene expression under environments different from training environments and in rice cultivars with more complex genotypes than the CSSLs. Our novel approach of eQTL identification facilitated the understanding of the genetic architecture of expression dynamics under field conditions, which is difficult to assess by conventional eQTL studies. The prediction of expression based on eQTLs and environmental information could contribute to the understanding of plant traits under diverse field conditions.
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Synthetic manipulation of the torsion angles in non-planar pi-conjugated dibenzo[g,p]chrysene (DBC) core was described. We prepared DBC scaffolds having four bromines at two bays, and found lithium -bromine exchange procedures ena...
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Synthetic manipulation of the torsion angles in non-planar pi-conjugated dibenzo[g,p]chrysene (DBC) core was described. We prepared DBC scaffolds having four bromines at two bays, and found lithium -bromine exchange procedures enabled to create new DBC derivatives. Crystallographic analyses revealed the largest torsion angle of 57.4 degrees in a tetra-sulfonyl-substituted DBC and the smallest torsion angle 31.8 degrees in a bis-silicon-bridged DBC. With the aid of computational method, these results mean the skeletal fused ring is flexibly movable within a range of 25.6 degrees. This study provides us an intellectual basis for development of distortion-featured functional organic materials. (c) 2022 Elsevier Ltd. All rights reserved.
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Effect of acidification on advanced oxidation performance of ozone-electrolysis was explored by experimental and theoretical approaches. A series of experiments revealed that ozone-electrolysis had a synergistic effect on 1,4-diox...
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Effect of acidification on advanced oxidation performance of ozone-electrolysis was explored by experimental and theoretical approaches. A series of experiments revealed that ozone-electrolysis had a synergistic effect on 1,4-dioxane removal. Two radical production pathways, namely ozone self-decomposition and one-electron reduction of ozone, are involved in ozone-electrolysis. A series of discussions based on the contribution of HO produced through ozone self-decomposition, chemical equilibrium of HO3/O-3(-), and equilibrium electrode potentials elucidated that acidification inhibited the one-electron reduction of ozone at the cathode through the enhancement of competitive two-electrons reduction of ozone by a change in the corresponding equilibrium electrode potential.
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In recent times, some researchers have successfully demonstrated the efficacy of UV photolysis of electrochemically generate free chlorine (UV/electro-chlorine) as for an advanced oxidation process. Since bromine as well as chlori...
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In recent times, some researchers have successfully demonstrated the efficacy of UV photolysis of electrochemically generate free chlorine (UV/electro-chlorine) as for an advanced oxidation process. Since bromine as well as chlorine is an element belonging to halogen, it is expected that UV photolysis of electrochemically generated free bromine (UV/electro-bromine) also shows an advanced oxidation effect. To elucidate the feasibility of UV/electro-bromine system, its advanced oxidation mechanism was investigated using radical probes of 1,4-dioxane and nitrobenzene. In contrast to the UV/electro-chlorine system, the advanced oxidation effect of UV/electro-bromine system was inhibited under acidic conditions due to the accumulation of photochemically inert Br-2. The most abundant radical in UV/electro-bromine system was dibromine radical anion (Br-2(-)) and the second-order reaction rate constant of Br-2(-) with 1,4-dioxane was estimated to be 2.4 x 10(5) M-1 s(-1). As a result of the abundance and the reactivity of Br-2(-), it was the main contributor to 1,4-dioxane degradation. On the other hand, nitrobenzene was mainly decomposed by direct UV photolysis because Br-2(-) does not react with nitrobenzene. The contribution of hydroxyl radical (HO) to 1,4-dioxane degradation was much lower than that of Br-2(-) because its concentration was 4-5 order of magnitude lower than that of Br-2(-). However, the HO concentration elevated with a decrease in the concentration of bromide ion (Br-). Consequently, the reactivity of Br-2(-) with pollutants and the Br- concentration have critical impacts on the advanced oxidation performance of UV/electro-bromine system.
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Artificially occurring parthenocarpy can be induced by exogenous application of plant hormones and is useful in the fruit production of many fruit crops and fruit trees. In cucumber (Cucumis sativus L.), a model species in the Cuc...
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Artificially occurring parthenocarpy can be induced by exogenous application of plant hormones and is useful in the fruit production of many fruit crops and fruit trees. In cucumber (Cucumis sativus L.), a model species in the Cucurbitaceae family, the plant hormones auxin, gibberellin, cytokinin, and brassinosteroids are known to induce parthenocarpy. In tropical squash (Cucurbita moschata L.), synthetic auxins are known to induce parthenocarpy, but the effects of gibberellin, cytokinin, and brassinosteroids are still unknown. In addition, there are few published reports on the quality of parthenocarpic fruits induced by plant hormones in tropical squash, and the effects of these hormones remain largely unknown. In this study, we examined the effects of gibberellin, cytokinin, and brassinosteroids on the parthenocarpy of tropical squash and characterized the parthenocarpic fruits induced by the plant hormones. First, we evaluated fruit set and development in unpollinated fruits of 'Kogiku', a tropical squash cultivar, treated with gibberellic acid (GA3), a synthetic cytokinin-like substance, N-(2-chloro-4-pyridyl)-N '-phenylurea (CPPU), and brassinolide (BL). CPPU promoted parthenocarpy, but GA3 and BL did not, showing that cytokinin works as an important factor for parthenocarpy in tropical squash. Next, we investigated the quality of parthenocarpic fruits from 'Kogiku' induced by a synthetic auxin, 1-naphthylacetic acid (NAA), and CPPU. Total soluble solids and myo-inositol of NAA-treated parthenocarpic fruit were higher than those of pollinated fruits, whereas fructose of NAA-treated parthenocarpic fruit and fructose and glucose of CPPU-treated parthenocarpic fruits were significantly lower than those of pollinated fruits. These results showed that parthenocarpy of tropical squash induced by auxin and cytokinin had differing effects on fruit quality.
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Gibberellins are widely used to induce seedlessness in table grape production, but are not effective for every cultivar or developmental stage. In order to characterize the potential physiological mechanism behind gibberellin-indu...
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Gibberellins are widely used to induce seedlessness in table grape production, but are not effective for every cultivar or developmental stage. In order to characterize the potential physiological mechanism behind gibberellin-induced seedlessness, we conducted tissue-specific transcriptome analysis of ovules and ovaries from cultivars with different levels of receptiveness to seedlessness induction. GA3 treatment at full bloom highly induced gibberellin signaling and various phytohormone signaling pathway genes in ovules at two days after treatment, but had less effect in ovaries, which suggests that GA3 directly affects seed development. During the development to six days after GA3 application, cell cycle-related genes in the ovules were markedly downregulated, indicating that this may be related to ovule abortion induction. The marked transcriptomic responses were largely absent in a cultivar with low receptiveness to gibberellin-induced seedlessness, suggesting a crucial role for the observed tissue-specific responses in the successful induction of seedlessness by GA3 application. Collectively, our transcriptome analysis highlights distinct tissue-specific reactions to GA3 during early berry development, providing important insights for the successful production of seedless berries by gibberellin application.
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