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1.
Proc Natl Acad Sci U S A ; 120(15): e2216632120, 2023 04 11.
Artículo en Inglés | MEDLINE | ID: mdl-37011193

RESUMEN

Spatiotemporal control of cell division in the meristem is vital for plant growth. In the stele of the root apical meristem (RAM), procambial cells divide periclinally to increase the number of vascular cell files. Class III homeodomain leucine zipper (HD-ZIP III) proteins are key transcriptional regulators of RAM development and suppress the periclinal division of vascular cells in the stele; however, the mechanism underlying the regulation of vascular cell division by HD-ZIP III transcription factors (TFs) remains largely unknown. Here, we performed transcriptome analysis to identify downstream genes of HD-ZIP III and found that HD-ZIP III TFs positively regulate brassinosteroid biosynthesis-related genes, such as CONSTITUTIVE PHOTOMORPHOGENIC DWARF (CPD), in vascular cells. Introduction of pREVOLUTA::CPD in a quadruple loss-of-function mutant of HD-ZIP III genes partly rescued the phenotype in terms of the vascular defect in the RAM. Treatment of a quadruple loss-of-function mutant, a gain-of-function mutant of HD-ZIP III, and the wild type with brassinosteroid and a brassinosteroid synthesis inhibitor also indicated that HD-ZIP III TFs act together to suppress vascular cell division by increasing brassinosteroid levels. Furthermore, brassinosteroid application suppressed the cytokinin response in vascular cells. Together, our findings suggest that the suppression of vascular cell division by HD-ZIP III TFs is caused, at least in part, by the increase in brassinosteroid levels through the transcriptional activation of brassinosteroid biosynthesis genes in the vascular cells of the RAM. This elevated brassinosteroid level suppresses cytokinin response in vascular cells, inhibiting vascular cell division in the RAM.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Meristema , Brasinoesteroides/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Leucina Zippers/genética , Citocininas/metabolismo , División Celular , Regulación de la Expresión Génica de las Plantas
2.
Plant Physiol ; 195(3): 2389-2405, 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38635969

RESUMEN

Glycogen synthase kinase 3 (GSK3) is an evolutionarily conserved serine/threonine protein kinase in eukaryotes. In plants, the GSK3-like kinase BRASSINOSTEROID-INSENSITIVE 2 (BIN2) functions as a central signaling node through which hormonal and environmental signals are integrated to regulate plant development and stress adaptation. BIN2 plays a major regulatory role in brassinosteroid (BR) signaling and is critical for phosphorylating/inactivating BRASSINAZOLE-RESISTANT 1 (BZR1), also known as BRZ-INSENSITIVE-LONG HYPOCOTYL 1 (BIL1), a master transcription factor of BR signaling, but the detailed regulatory mechanism of BIN2 action has not been fully revealed. In this study, we identified BIL8 as a positive regulator of BR signaling and plant growth in Arabidopsis (Arabidopsis thaliana). Genetic and biochemical analyses showed that BIL8 is downstream of the BR receptor BRASSINOSTEROID-INSENSITIVE 1 (BRI1) and promotes the dephosphorylation of BIL1/BZR1. BIL8 interacts with and inhibits the activity of the BIN2 kinase, leading to the accumulation of dephosphorylated BIL1/BZR1. BIL8 suppresses the cytoplasmic localization of BIL1/BZR1, which is induced via BIN2-mediated phosphorylation. Our study reveals a regulatory factor, BIL8, that positively regulates BR signaling by inhibiting BIN2 activity.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Brasinoesteroides , Regulación de la Expresión Génica de las Plantas , Transducción de Señal , Brasinoesteroides/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Fosforilación , Proteínas Quinasas/metabolismo , Proteínas Quinasas/genética , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética
3.
Plant Cell Physiol ; 2024 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-38242155

RESUMEN

Drought stress is a major threat leading to global plant and crop losses in the context of the climate change crisis. Brassinosteroids (BRs) are plant steroid hormones, and the BR signaling mechanism in plant development has been well elucidated. Nevertheless, the specific mechanisms of BR signaling in drought stress are still unclear. Here, we identify a novel Arabidopsis gene, BRZ INSENSITIVE LONG HYPOCOTYL 9 (BIL9), which promotes plant growth via BR signaling. Overexpression of BIL9 enhances drought and mannitol stress resistance and increases the expression of drought-responsive genes. BIL9 protein is induced by dehydration and interacts with the HD-Zip IV transcription factor HOMEODOMAIN GLABROUS 11 (HDG11), which is known to promote plant resistance to drought stress, in vitro and in vivo. BIL9 enhanced the transcriptional activity of HDG11 for drought-stress-resistant genes. BIL9 is a novel BR signaling factor that enhances both plant growth and plant drought resistance.

4.
Physiol Plant ; 174(1): e13598, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34792189

RESUMEN

Diatoms adapt to various aquatic light environments and play major roles in the global carbon cycle using their unique light-harvesting system, i.e. fucoxanthin chlorophyll a/c binding proteins (FCPs). Structural analyses of photosystem II (PSII)-FCPII and photosystem I (PSI)-FCPI complexes from the diatom Chaetoceros gracilis have revealed the localization and interactions of many FCPs; however, the entire set of FCPs has not been characterized. Here, we identify 46 FCPs in the newly assembled genome and transcriptome of C. gracilis. Phylogenetic analyses suggest that these FCPs can be classified into five subfamilies: Lhcr, Lhcf, Lhcx, Lhcz, and the novel Lhcq, in addition to a distinct type of Lhcr, CgLhcr9. The FCPs in Lhcr, including CgLhcr9 and some Lhcqs, have orthologous proteins in other diatoms, particularly those found in the PSI-FCPI structure. By contrast, the Lhcf subfamily, some of which were found in the PSII-FCPII complex, seems to be diversified in each diatom species, and the number of Lhcqs differs among species, indicating that their diversification may contribute to species-specific adaptations to light. Further phylogenetic analyses of FCPs/light-harvesting complex (LHC) proteins using genome data and assembled transcriptomes of other diatoms and microalgae in public databases suggest that our proposed classification of FCPs is common among various red-lineage algae derived from secondary endosymbiosis of red algae, including Haptophyta. These results provide insights into the loss and gain of FCP/LHC subfamilies during the evolutionary history of the red algal lineage.


Asunto(s)
Proteínas de Unión a Clorofila , Diatomeas , Clorofila A/química , Proteínas de Unión a Clorofila/genética , Proteínas de Unión a Clorofila/metabolismo , Diatomeas/genética , Diatomeas/metabolismo , Complejos de Proteína Captadores de Luz/metabolismo , Filogenia , Xantófilas
5.
Environ Sci Technol ; 56(14): 10204-10215, 2022 07 19.
Artículo en Inglés | MEDLINE | ID: mdl-35801261

RESUMEN

Although polychlorinated biphenyls (PCBs) were commercially banned half a century ago, contamination of the environment and organisms by PCBs is still observed. PCBs show high persistence and bioaccumulation, resulting in toxicity. Among PCBs, chiral PCBs with more than three chlorine atoms at the ortho-position exhibit developmental and neurodevelopmental toxicity. Because toxicity is dependent on the atropisomer, atropisomer-specific metabolism is vital in determining toxicity. However, structural information on enantioselective metabolism remains elusive. Cytochrome P450 (CYP, P450) monooxygenases, particularly human CYP2B6 and rat CYP2B1, metabolize separated atropisomers of 2,2',3,6-tetrachlorobiphenyl (CB45) and 2,2',3,4',6-pentachlorobiphenyl (CB91) to dechlorinated and hydroxylated metabolites. Docking studies using human CYP2B6 predict 4'-hydroxy (OH)-CB45 from (aR)-CB45 as a major metabolite of CB45. Di-OH- and dechlorinated OH-metabolites from human CYP2B6 and rat CYP2B1 are also detected. Several hydroxylated metabolites are derived from CB91 by both P450s; 5-OH-CB91 is predicted as a major metabolite. CB91 dechlorination is also detected by identifying 3-OH-CB51. A stable conformation of PCBs in the substrate-binding cavity and close distance to P450 heme are responsible for high metabolizing activities. As hydroxylation and dechlorination change PCB toxicity, this approach helps understand the possible toxicity of chiral PCBs in mammals.


Asunto(s)
Bifenilos Policlorados , Animales , Citocromo P-450 CYP2B1/metabolismo , Citocromo P-450 CYP2B6/metabolismo , Sistema Enzimático del Citocromo P-450/metabolismo , Humanos , Hidroxilación , Mamíferos/metabolismo , Bifenilos Policlorados/metabolismo , Ratas , Estereoisomerismo
6.
Biosci Biotechnol Biochem ; 86(8): 1041-1048, 2022 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-35583242

RESUMEN

Brassinosteroids (BRs), a kind of phytohormone, have various biological activities such as promoting plant growth, increasing stress resistance, and chloroplast development. Though BRs have been known to have physiological effects on chloroplast, the detailed mechanism of chloroplast development and chlorophyll biosynthesis in BR signaling remains unknown. Here we identified a recessive pale green Arabidopsis mutant, Brz-insensitive-pale green1 (bpg1), which was insensitive to promoting of greening by BR biosynthesis-specific inhibitor Brz in the light. BPG1 gene encoded chlorophyll biosynthesis enzyme, 3, 8-divinyl protochlorophyllide a 8-vinyl reductase (DVR), and bpg1 accumulated divinyl chlorophylls. Chloroplast development was suppressed in bpg1. Brz dramatically increased the expression of chlorophyll biosynthesis enzyme genes, including BPG1. These results suggest that chlorophyll biosynthesis enzymes are regulated by BR signaling in the aspect of gene expression and BPG1 plays an important role in regulating chloroplast development.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Brasinoesteroides/metabolismo , Clorofila/metabolismo , Regulación de la Expresión Génica de las Plantas
7.
Biosci Biotechnol Biochem ; 86(8): 1004-1012, 2022 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-35687006

RESUMEN

Brassinolide (BL) is a possible plant growth regulator in agriculture, but the presence of a steroid skeleton hampers the field application of BL in agriculture because of its high synthetic cost. We discovered NSBR1 as the first nonsteroidal BL-like compound using in silico technology. Searching for more potent BL-like compounds, we modified the structure of NSBR1 with respect to 2 benzene rings and the piperazine ring. The activity of synthesized compounds was measured in Arabidopsis hypocotyl elongation. The propyl group of butyryl moiety of NSBR1 was changed to various alkyl groups, such as straight, branched, and cyclic alkyl chains. Another substituent, F, at the ortho position of the B ring toward the piperazine ring was changed to other substituents. A methyl group was introduced to the piperazine ring. Most of the newly synthesized compounds with the 3,4-(OH)2 group at the A ring significantly elongated the hypocotyl of Arabidopsis.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Esteroides Heterocíclicos , Brasinoesteroides , Piperazinas , Esteroides Heterocíclicos/farmacología
8.
J Plant Res ; 135(5): 681-692, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35767130

RESUMEN

Low temperature inhibits photosynthesis and negatively affects plant growth. Cucumber (Cucumis sativus L.) is a chilling-sensitive plant, and its greenhouse production requires considerable energy during the winter. Therefore, a useful stress marker for selecting chilling-tolerant cucumber cultivars is desirable. In this study, we evaluated chilling-stress damage in different cucumber cultivars by measuring photosynthetic parameters. The majority of cultivars showed decreases in the quantum yield of photosystem (PS) II [Fv/Fm and Y(II)] and the quantity of active PS I (Pm) after chilling stress. In contrast, Y(ND)-the ratio of the oxidized state of PSI reaction center chlorophyll P700 (P700+)-differed among cultivars and was perfectly inversely correlated with Y(NA)-the ratio of the non-photooxidizable P700. It has been known that P700+ accumulates under stress conditions and protects plants to suppress the generation of reactive oxygen species. In fact, cultivars unable to induce Y(ND) after chilling stress showed growth retardation with reductions in chlorophyll content and leaf area. Therefore, Y(ND) can be a useful marker to evaluate chilling-stress tolerance in cucumber.


Asunto(s)
Cucumis sativus , Complejo de Proteína del Fotosistema I , Clorofila , Frío , Fotosíntesis , Complejo de Proteína del Fotosistema I/metabolismo , Complejo de Proteína del Fotosistema II/metabolismo , Hojas de la Planta/metabolismo
9.
J Plant Res ; 134(6): 1335-1349, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34477986

RESUMEN

Although anthocyanins are widely distributed in higher plants, betalains have replaced anthocyanins in most species of the order Caryophyllales. The accumulation of flavonols in Caryophyllales plants implies that the late step of anthocyanin biosynthesis from dihydroflavonols to anthocyanins may be blocked in Caryophyllales. The isolation and characterization of functional dihydroflavonol 4-reductase (DFR) and anthocyanidin synthase (ANS) from Caryophyllales plants has indicated a lack of anthocyanins due to suppression of DFR and ANS. In this study, we demonstrated that overexpression of DFR and ANS from Spinacia oleracea (SoDFR and SoANS, respectively) with PhAN9, which encodes glutathione S-transferase (required for anthocyanin sequestration) from Petunia induces ectopic anthocyanin accumulation in yellow tepals of the cactus Astrophytum myriostigma. A promoter assay of SoANS showed that the Arabidopsis MYB transcription factor PRODUCTION OF ANTHOCYANIN PIGMENT1 (PAP1) activated the SoANS promoter in Arabidopsis leaves. The overexpression of Arabidopsis transcription factors with PhAN9 also induced ectopic anthocyanin accumulation in yellow cactus tepals. PAP homologs from betalain-producing Caryophyllales did not activate the promoter of ANS. In-depth characterization of Caryophyllales PAPs and site-directed mutagenesis in the R2R3-MYB domains identified the amino acid residues affecting transactivation of Caryophyllales PAPs. The substitution of amino acid residues recovered the transactivation ability of Caryophyllales PAPs. Therefore, loss of function in MYB transcription factors may suppress expression of genes involved in the late stage of anthocyanin synthesis, resulting in a lack of anthocyanin in betalain-producing Caryophyllales plants.


Asunto(s)
Arabidopsis , Caryophyllales , Antocianinas , Arabidopsis/genética , Arabidopsis/metabolismo , Betalaínas/metabolismo , Caryophyllales/genética , Regulación de la Expresión Génica de las Plantas , Hojas de la Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/metabolismo
10.
Plant Cell Physiol ; 61(7): 1252-1261, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32333781

RESUMEN

Angiosperms have three PsbQ-like (PQL) proteins in addition to the PsbQ subunit of the oxygen-evolving complex of photosystem II. Previous studies have shown that two PQL proteins, PnsL2 and PnsL3, are subunits of the chloroplast NADH dehydrogenase-like (NDH) complex involved in the photosystem I (PSI) cyclic electron flow. In addition, another PsbQ homolog, PQL3, is required for the NDH activity; however, the molecular function of PQL3 has not been elucidated. Here, we show that PQL3 is an assembly factor, particularly for the accumulation of subcomplex B (SubB) of the chloroplast NDH. In the pql3 mutant of Arabidopsis thaliana, the amounts of NDH subunits in SubB, PnsB1 and PsnB4, were decreased, causing a severe reduction in the NDH-PSI supercomplex. Analysis using blue native polyacrylamide gel electrophoresis suggested that the incorporation of PnsL3 into SubB was affected in the pql3 mutant. Unlike other PsbQ homologs, PQL3 was weakly associated with thylakoid membranes and was only partially protected from thermolysin digestion. Consistent with the function as an assembly factor, PQL3 accumulated independently in other NDH mutants, such as pnsl1-3. Furthermore, PQL3 accumulated in young leaves in a manner similar to the accumulation of CRR3, an assembly factor for SubB. These results suggest that PQL3 has developed a distinct function as an assembly factor for the NDH complex during evolution of the PsbQ protein family in angiosperms.


Asunto(s)
Proteínas de Arabidopsis/fisiología , Arabidopsis/metabolismo , Cloroplastos/enzimología , NADH Deshidrogenasa/metabolismo , Complejo de Proteína del Fotosistema II/fisiología , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Cloroplastos/metabolismo , Complejo de Proteína del Fotosistema I/metabolismo , Complejo de Proteína del Fotosistema II/genética , Complejo de Proteína del Fotosistema II/metabolismo , Filogenia , Hojas de la Planta/metabolismo , Tilacoides/metabolismo
11.
Plant Cell Physiol ; 61(6): 1168-1180, 2020 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-32277833

RESUMEN

In green plants, photosystem II (PSII) forms multisubunit supercomplexes (SCs) containing a dimeric core and light-harvesting complexes (LHCs). In this study, we show that Arabidopsis thaliana PsbP-like protein 1 (PPL1) is involved in the assembly of the PSII SCs and is required for adaptation to changing light intensity. PPL1 is a homolog of PsbP protein that optimizes the water-oxidizing reaction of PSII in green plants and is required for the efficient repair of photodamaged PSII; however, its exact function has been unknown. PPL1 was enriched in stroma lamellae and grana margins and associated with PSII subcomplexes including PSII monomers and PSII dimers, and several LHCII assemblies, while PPL1 was not detected in PSII-LHCII SCs. In a PPL1 null mutant (ppl1-2), assembly of CP43, PsbR and PsbW was affected, resulting in a reduced accumulation of PSII SCs even under moderate light intensity. This caused the abnormal association of LHCII in ppl1-2, as indicated by lower maximal quantum efficiency of PSII (Fv/Fm) and accelerated State 1 to State 2 transitions. These differences would lower the capability of plants to adapt to changing light environments, thereby leading to reduced growth under natural fluctuating light environments. Phylogenetic and structural analyses suggest that PPL1 is closely related to its cyanobacterial homolog CyanoP, which functions as an assembly factor in the early stage of PSII biogenesis. Our results suggest that PPL1 has a similar function, but the data also indicate that it could aid the association of LHCII with PSII.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Complejo de Proteína del Fotosistema II/metabolismo , Arabidopsis/genética , Arabidopsis/fisiología , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/fisiología , Luz , Complejo de Proteína del Fotosistema II/genética , Complejo de Proteína del Fotosistema II/fisiología , Filogenia , Estructura Terciaria de Proteína , Reacción en Cadena en Tiempo Real de la Polimerasa , Alineación de Secuencia , Tilacoides/metabolismo
12.
Plant Cell Physiol ; 59(8): 1555-1567, 2018 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-30053249

RESUMEN

Auxin and cytokinin control callus formation from developed plant organs as well as shoot regeneration from callus. Dedifferentiation and regeneration of plant cells by auxin and cytokinin stimulation are considered to be caused by the reprogramming of callus cells, but this hypothesis is still argued to this day. Although an elucidation of the regulatory mechanisms of callus formation and shoot regeneration has helped advance plant biotechnology research, many plant species are intractable to transformation because of difficulties with callus formation. In this study, we identified fipexide (FPX) as a useful regulatory compound through a chemical biology-based screening. FPX was shown to act as a chemical inducer in callus formation, shoot regeneration and Agrobacterium infection. With regards to morphology, the cellular organization of FPX-induced calli differed from those produced under auxin/cytokinin conditions. Microarray analysis revealed that the expression of approximately 971 genes was up-regulated 2-fold after a 2 d FPX treatment compared with non-treated plants. Among these 971 genes, 598 genes were also induced by auxin/cytokinin, whereas 373 genes were specifically expressed upon FPX treatment only. FPX can promote callus formations in rice, poplar, soybean, tomato and cucumber, and thus can be considered a useful tool for revealing the mechanisms of plant development and for use in plant transformation technologies.


Asunto(s)
Piperazinas/farmacología , Brotes de la Planta/efectos de los fármacos , Brotes de la Planta/metabolismo , Citocininas/metabolismo , Ácidos Indolacéticos/metabolismo , Brotes de la Planta/fisiología
13.
Blood Cells Mol Dis ; 68: 194-199, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-27866810

RESUMEN

Gaucher disease is a lysosomal storage disease caused by deficiency of glucocerebrosidase and accumulation of glucocerebroside. Three major sub-types have been described, type 2 is an acute neurological form that exhibits serious general symptoms and poor prognosis, compared with the other types. This case was a girl diagnosed with type 2 Gaucher disease at 12months of age who presented with poor weight gain from infancy, stridor, hypertonia, hepatosplenomegaly, trismus and an eye movement disorder. Enzyme replacement therapy (ERT) was administered, but she had frequent myoclonus and developmental regression. She needed artificial ventilation because of respiratory failure. She died at 11years of age. An autopsy demonstrated infiltrating CD68-positive large cells containing abundant lipids in alveoli, while in the liver, kidney and bone marrow CD68-positive cells were small and round. In the bone marrow, myelodysplastic changes were present without Gaucher cells. The infiltration of Gaucher cells in alveoli was marked, suggesting that ERT was relatively ineffective in pulmonary involvement, particularly intra-alveolar. Additional treatments are necessary to improve the neurological and pulmonary prognosis of type 2Gaucher disease.


Asunto(s)
Enfermedad de Gaucher/tratamiento farmacológico , Enfermedad de Gaucher/patología , Glucosilceramidasa/uso terapéutico , Antígenos CD/análisis , Antígenos de Diferenciación Mielomonocítica/análisis , Autopsia , Médula Ósea/efectos de los fármacos , Médula Ósea/patología , Niño , Terapia de Reemplazo Enzimático , Femenino , Enfermedad de Gaucher/complicaciones , Humanos , Riñón/efectos de los fármacos , Riñón/patología , Hígado/efectos de los fármacos , Hígado/patología , Pulmón/efectos de los fármacos , Pulmón/patología , Vísceras/efectos de los fármacos , Vísceras/patología
14.
Plant Physiol ; 173(1): 825-835, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27899534

RESUMEN

Gibberellin (GA) is a major plant hormone that regulates plant growth and development and is widely used as a plant growth regulator in agricultural production. There is an increasing demand for function-limited GA mimics due to the limitations on the agronomical application of GA to crops, including GA's high cost of producing and its leading to the crops' lodging. AC94377, a substituted phthalimide, is a chemical that mimics the growth-regulating activity of GAs in various plants, despite its structural difference. Although AC94377 is widely studied in many weeds and crops, its mode of action as a GA mimic is largely unknown. In this study, we confirmed that AC94377 displays GA-like activities in Arabidopsis (Arabidopsis thaliana) and demonstrated that AC94377 binds to the Arabidopsis GIBBERELLIN INSENSITIVE DWARF1 (GID1) receptor (AtGID1), forms the AtGID1-AC94377-DELLA complex, and induces the degradation of DELLA protein. Our results also indicated that AC94377 is selective for a specific subtype among three AtGID1s and that the selectivity of AC94377 is attributable to a single residue at the entrance to the hydrophobic pocket of GID1. We conclude that AC94377 is a GID1 agonist with selectivity for a specific subtype of GID1, which could be further developed and used as a function-limited regulator of plant growth in both basic study and agriculture.


Asunto(s)
Proteínas de Arabidopsis/agonistas , Arabidopsis/efectos de los fármacos , Ftalimidas/química , Ftalimidas/farmacología , Receptores de Superficie Celular/agonistas , Arabidopsis/metabolismo , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Germinación/efectos de los fármacos , Giberelinas/metabolismo , Hipocótilo/efectos de los fármacos , Ftalimidas/metabolismo , Plantas Modificadas Genéticamente , Receptores de Superficie Celular/química , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Transducción de Señal/efectos de los fármacos , Nicotiana/genética
15.
Plant Cell ; 27(2): 375-90, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25663622

RESUMEN

Brassinosteroids (BRs) play important roles in plant development and the response to environmental cues. BIL1/BZR1 is a master transcription factor in BR signaling, but the mechanisms that lead to the finely tuned targeting of BIL1/BZR1 by BRs are unknown. Here, we identified BRZ-SENSITIVE-SHORT HYPOCOTYL1 (BSS1) as a negative regulator of BR signaling in a chemical-biological analysis involving brassinazole (Brz), a specific BR biosynthesis inhibitor. The bss1-1D mutant, which overexpresses BSS1, exhibited a Brz-hypersensitive phenotype in hypocotyl elongation. BSS1 encodes a BTB-POZ domain protein with ankyrin repeats, known as BLADE ON PETIOLE1 (BOP1), which is an important regulator of leaf morphogenesis. The bss1-1D mutant exhibited an increased accumulation of phosphorylated BIL1/BZR1 and a negative regulation of BR-responsive genes. The number of fluorescent BSS1/BOP1-GFP puncta increased in response to Brz treatment, and the puncta were diffused by BR treatment in the root and hypocotyl. We show that BSS1/BOP1 directly interacts with BIL1/BZR1 or BES1. The large protein complex formed between BSS1/BOP1 and BIL1/BZR1 was only detected in the cytosol. The nuclear BIL1/BZR1 increased in the BSS1/BOP1-deficient background and decreased in the BSS1/BOP1-overexpressing background. Our study suggests that the BSS1/BOP1 protein complex inhibits the transport of BIL1/BZR1 to the nucleus from the cytosol and negatively regulates BR signaling.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Brasinoesteroides/metabolismo , Complejos Multiproteicos/metabolismo , Desarrollo de la Planta , Transducción de Señal , Arabidopsis/efectos de los fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Brasinoesteroides/farmacología , Núcleo Celular/efectos de los fármacos , Núcleo Celular/metabolismo , Citosol/efectos de los fármacos , Citosol/metabolismo , Oscuridad , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Proteínas Fluorescentes Verdes/metabolismo , Modelos Biológicos , Mutación/genética , Fenotipo , Desarrollo de la Planta/efectos de los fármacos , Unión Proteica/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Triazoles/farmacología
16.
Nat Chem Biol ; 12(11): 967-972, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28288097

RESUMEN

Amino-group carrier proteins (AmCPs) mediate the biosynthesis of lysine and arginine in some bacteria and archaea. Here we demonstrate that an uncharacterized AmCP-mediated biosynthetic system functions to biosynthesize the previously uncharacterized and nonproteinogenic amino acid (2S,6R)-diamino-(5R,7)-dihydroxy-heptanoic acid (DADH) in Streptomyces sp. SANK 60404. DADH is incorporated into a novel peptide metabolite, vazabitide A, featuring an azabicyclo-ring structure, by nonribosomal peptide synthetases and successive modification enzymes in this bacterium. As the AmCP-mediated machinery for DADH biosynthesis is widely distributed in bacteria, further analysis of uncharacterized AmCP-containing gene clusters will lead to the discovery of novel bioactive compounds and novel biosynthetic enzymes.


Asunto(s)
Arginina/biosíntesis , Proteínas Portadoras/metabolismo , Lisina/biosíntesis , Metabolismo Secundario , Streptomyces/metabolismo , Arginina/química , Lisina/química
17.
Anal Bioanal Chem ; 410(6): 1825-1831, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29313081

RESUMEN

We developed capillary zone electrophoresis (CZE) with indirect UV detection for the determination of fluoride (F-) in seawater using transient isotachophoresis (tITP) as an on-line concentration procedure. A method of correcting sample salinity effects was also proposed so that F- concentrations were obtained using a calibration graph. The proposed method is simple: it requires no sample pretreatment aside from dilution. The following optimum conditions were established: background electrolyte (BGE), 5 mM 2,6-pyridinedicarboxylic acid (PDC) adjusted to pH 3.5 containing 0.03% m/v hydroxypropyl methylcellulose (HPMC); detection wavelength, 200 nm; vacuum (50 kPa) injection period of sample, 5 s (254 nL); and applied voltage, 23 kV with the sample inlet side as the cathode. The limit of detection (LOD, S/N = 3) and limit of quantification (LOQ, S/N = 10) for F- reached 0.024 and 0.070 mg/L, respectively. The respective values of the relative standard deviation (RSD) of the peak area, peak height, and migration time for F- were 2.5, 3.4, and 0.30%. The proposed method was applied for the determination of F- in seawater samples collected from coastal waters of western Japan during August 26-28, 2014. Both results obtained using standard addition method and a calibration graph agreed with those obtained using a conventional spectrophotometric method.

18.
Biosci Biotechnol Biochem ; 82(10): 1770-1779, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29912637

RESUMEN

We previously found a chemical, designated as NJ15, which inhibited both auxin and brassinosteroid responses in dark-grown Arabidopsis. To study its mode of action, we performed a phenotypic screening of NJ15-low-sensitive lines among mutant pools of Arabidopsis. One line (f127) showed clear NJ15-low-sensitivity in terms of hypocotyl elongation and shoot gravitropism. After further testing, it was determined that DCR, an enzyme involved in cutin polymerization, had lost its function in the mutant, which caused its low sensitivity to NJ15. Fatty acids are the base materials for polymers such as cutin and cuticular wax. We confirmed that NJ15 affects fatty acid biosynthesis, and that it does differently from cafenstrole, a known inhibitor of cuticular wax formation. Based on these results, we propose that the target of NJ15 is likely located within the cutin polymer formation pathway. ABBREVIATIONS: Caf: cafenstrole; DEG: differentially expressed gene; FDR: false discovery rate; FOX: full length cDNA-overexpressor; VLCFA: very-long-chain fatty acid.


Asunto(s)
Arabidopsis/efectos de los fármacos , Gravitropismo/efectos de los fármacos , Hipocótilo/efectos de los fármacos , Lípidos de la Membrana/metabolismo , Brotes de la Planta/efectos de los fármacos , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Ácidos Grasos/metabolismo , Hipocótilo/crecimiento & desarrollo , Mutación , Brotes de la Planta/crecimiento & desarrollo , Polimerizacion , Reacción en Cadena en Tiempo Real de la Polimerasa , Análisis de Secuencia de ARN , Sulfonas/farmacología , Transcriptoma , Triazoles/farmacología
19.
Ecotoxicol Environ Saf ; 147: 367-372, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28869886

RESUMEN

The red-crowned crane (Grus japonensis) from eastern Hokkaido is classified as a Special Natural Monument in Japan. In this study, we determined the concentrations of persistent organic pollutants (POPs) in red-crowned crane muscle tissues (n = 47). Polychlorinated biphenyls (PCBs) had the highest median concentration (240ng/g lipid weight), followed by dichlorodiphenyltrichloroethane and its metabolites (DDTs) (150ng/g lipid weight), chlordane-related compounds (CHLs) (36ng/g lipid weight), hexachlorobenzene (HCB) (16ng/g lipid weight), hexachlorocyclohexanes (HCHs) (4.4ng/g lipid weight), polybrominated diphenyl ethers (PBDEs) (1.8ng/g lipid weight), and finally, Mirex (1.5ng/g lipid weight). Additionally, a positive correlation was found among POP concentrations. No sex differences beyond body parameters were observed. Additionally, red-crowned cranes exhibited a high enantiomeric excess of (+)-alpha-HCH, with enantiomer fractions varying from 0.51 to 0.87 (average: 0.69).


Asunto(s)
Aves/metabolismo , Disruptores Endocrinos/análisis , Monitoreo del Ambiente/métodos , Contaminantes Ambientales/análisis , Compuestos Orgánicos/análisis , Animales , Aves/crecimiento & desarrollo , Peso Corporal/efectos de los fármacos , Disruptores Endocrinos/metabolismo , Contaminantes Ambientales/metabolismo , Japón , Músculo Esquelético/química , Músculo Esquelético/metabolismo , Compuestos Orgánicos/metabolismo , Distribución Tisular
20.
Photochem Photobiol Sci ; 16(4): 606-610, 2017 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-28186216

RESUMEN

Circular dichroisms (CDs) of the o,p'-isomers of 1,1,1-trichloro- and 1,1-dichloro-2,2-bis(chlorophenyl)ethanes (DDT and DDD) were investigated experimentally and theoretically. A series of strong Cotton effect peaks in a characteristic negative-negative-positive-negative, or its mirror-imaged, pattern were observed in the CD spectra of these persistent organic pollutants. The theoretical CD spectra at the SAC-CI/B95(d) and RI-CC2/def2-TZVPP levels well reproduced the experimental ones, enabling us to unambiguously assign the absolute configuration of (+)-DDT and (-)-DDD as S.

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