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1.
Plant Cell ; 35(2): 874-888, 2023 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-36427255

RESUMO

The endosperm is a nutritive tissue supporting embryo growth in flowering plants. Most commonly, the endosperm initially develops as a coenocyte (multinucleate cell) and then cellularizes. This process of cellularization is frequently disrupted in hybrid seeds generated by crosses between different flowering plant species or plants that differ in ploidy, resulting in embryo arrest and seed lethality. The reason for embryo arrest upon cellularization failure remains unclear. In this study, we show that triploid Arabidopsis thaliana embryos surrounded by uncellularized endosperm mount an osmotic stress response that is connected to increased levels of abscisic acid (ABA) and enhanced ABA responses. Impairing ABA biosynthesis and signaling aggravated triploid seed abortion, while increasing endogenous ABA levels as well as the exogenous application of ABA-induced endosperm cellularization and suppressed embryo growth arrest. Taking these results together, we propose that endosperm cellularization is required to establish dehydration tolerance in the developing embryo, ensuring its survival during seed maturation.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Endosperma/genética , Endosperma/metabolismo , Proteínas de Arabidopsis/metabolismo , Triploidia , Desidratação , Arabidopsis/metabolismo , Sementes/metabolismo , Regulação da Expressão Gênica de Plantas/genética
2.
Plant J ; 117(6): 1873-1892, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38168757

RESUMO

Global climate change is predicted to result in increased yield losses of agricultural crops caused by environmental conditions. In particular, heat and drought stress are major factors that negatively affect plant development and reproduction, and previous studies have revealed how these stresses induce plant responses at physiological and molecular levels. Here, we provide a comprehensive overview of current knowledge concerning how drought, heat, and combinations of these stress conditions affect the status of plants, including crops, by affecting factors such as stomatal conductance, photosynthetic activity, cellular oxidative conditions, metabolomic profiles, and molecular signaling mechanisms. We further discuss stress-responsive regulatory factors such as transcription factors and signaling factors, which play critical roles in adaptation to both drought and heat stress conditions and potentially function as 'hubs' in drought and/or heat stress responses. Additionally, we present recent findings based on forward genetic approaches that reveal natural variations in agricultural crops that play critical roles in agricultural traits under drought and/or heat conditions. Finally, we provide an overview of the application of decades of study results to actual agricultural fields as a strategy to increase drought and/or heat stress tolerance. This review summarizes our current understanding of plant responses to drought, heat, and combinations of these stress conditions.


Assuntos
Mudança Climática , Secas , Resposta ao Choque Térmico , Produtos Agrícolas/genética , Desenvolvimento Vegetal , Estresse Fisiológico/genética
3.
J Exp Bot ; 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38721634

RESUMO

As sessile organisms, plants enter periods of dormancy in response to environmental stresses to ensure continued growth and reproduction in future. During dormancy, plant growth is suppressed, adaptive/survival mechanisms are exerted, and stress tolerance increases over a prolonged period until the plants resume their development or reproduction under favorable conditions. In this review, we focus on seed dormancy and bud dormancy, which are critical for adaptations to fluctuating environmental conditions. We provide an overview of the physiological characteristics of both types of dormancy as well as the importance of the phytohormones abscissic acid and gibberellin for establishing and releasing dormancy, respectively. Additionally, recent epigenetic analyses have revealed that dormancy establishment and release are associated with the removal and deposition of histone modifications at the loci of key regulatory genes influencing phytohormone metabolism and signaling, including DELAY OF GERMINATION 1 and DORMANCY-ASSOCIATED MADS-box genes. We discuss our current understanding of the physiological and molecular mechanisms required to establish and release seed dormancy and bud dormancy, while also describing how environmental conditions control dormancy depth, with a focus on the effects of histone modifications.

4.
Sensors (Basel) ; 24(7)2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38610231

RESUMO

The purpose of this study was to investigate the relationship between clinical outcomes and lateral thrust before and after unicompartmental knee arthroplasty (UKA) using inertial measurement sensor units. Eleven knees were evaluated with gait analysis. The varus angular velocity was used to evaluate lateral thrust. The femorotibial angle (FTA) and hip-knee-ankle angle (HKA) were used to evaluate lower-limb alignment, and the Oxford Knee Score (OKS) and Japanese Orthopaedic Association Score (JOA) were used to evaluate clinical outcomes. The mean pre-UKA peak varus velocity was 37.1 ± 9.8°/s, and that for post-UKA was 28.8 ± 9.1°/s (p = 0.00003), such that instabilities clearly improved. Assuming the definition of lateral thrust is when the varus angular velocity is more than 28.1°/s, 81.8% of patients had lateral thrust preoperatively, but this decreased to 55.6% postoperatively, such that the symptoms and objective findings improved. Both OKS and JOA improved after surgery. In addition, HKA was -7.9° preoperatively and -5.8° postoperatively (p = 0.024), and FTA was 181.4° preoperatively and 178.4° postoperatively (p = 0.012). There was a positive correlation between postoperative JOA and FTA, indicating that changes in postoperative alignment affected clinical outcomes. This study quantitatively evaluated the disappearance of lateral thrust by UKA, and it found that the stability can be achieved by UKA for unstable knees with lateral thrust.


Assuntos
Artroplastia do Joelho , Osteoartrite , Humanos , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/cirurgia , Extremidade Inferior , Articulação do Tornozelo
5.
Plant Physiol ; 185(4): 2003-2021, 2021 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-33566101

RESUMO

The Polycomb Repressive Complex 2 (PRC2) is well-known for its role in controlling developmental transitions by suppressing the premature expression of key developmental regulators. Previous work revealed that PRC2 also controls the onset of senescence, a form of developmental programmed cell death (PCD) in plants. Whether the induction of PCD in response to stress is similarly suppressed by the PRC2 remained largely unknown. In this study, we explored whether PCD triggered in response to immunity- and disease-promoting pathogen effectors is associated with changes in the distribution of the PRC2-mediated histone H3 lysine 27 trimethylation (H3K27me3) modification in Arabidopsis thaliana. We furthermore tested the distribution of the heterochromatic histone mark H3K9me2, which is established, to a large extent, by the H3K9 methyltransferase KRYPTONITE, and occupies chromatin regions generally not targeted by PRC2. We report that effector-induced PCD caused major changes in the distribution of both repressive epigenetic modifications and that both modifications have a regulatory role and impact on the onset of PCD during pathogen infection. Our work highlights that the transition to pathogen-induced PCD is epigenetically controlled, revealing striking similarities to developmental PCD.


Assuntos
Apoptose/fisiologia , Arabidopsis/genética , Arabidopsis/microbiologia , Arabidopsis/fisiologia , Interações Hospedeiro-Patógeno/fisiologia , Complexo Repressor Polycomb 2/genética , Complexo Repressor Polycomb 2/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Interações Hospedeiro-Patógeno/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia
6.
J Microsc ; 288(2): 117-129, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-34028848

RESUMO

We improved the three-dimensional spatial resolution of laser scanning transmission microscopy by exploiting the saturated absorption of dye molecules. The saturated absorption is induced by the high-intensity light irradiation and localises the signal within the centre of the focal spot. Our numerical calculation indicates that the spatial resolution in transmission imaging is significantly improved for both lateral and axial directions using nonlinear transmitted signals induced by saturated absorption. We experimentally demonstrated the improvement of the three-dimensional resolution by observing fine structures of stained rat kidney tissues, which were not able to be visualised by conventional laser scanning transmission microscopy.


Confocal laser scanning microscopy is a powerful technique for three-dimensional imaging to study structures in a specimen. The use of confocal pinhole provides three-dimensional spatial resolution in various types of optical microscopes, such as fluorescence, reflection and scattering. However, in transmission microscopy, the confocal pinhole cannot provide the same effect because the spatial information on the optical axial is not transferred in the imaging system. Therefore, the three-dimensional distribution of light absorbers cannot be observed by laser scanning transmission microscopy. In this paper, we propose the use of saturated absorption to image the three-dimensional distribution of light absorbers in a sample by laser scanning transmission microscopy. The saturated absorption is induced by the high-intensity light irradiation and occurs prominently at the centre of a focal spot. The information of the saturated absorption signal within the focal spot is transferred to the transmitted light, providing the capability of optical sectioning in transmission imaging. In our research, we theoretically and experimentally confirmed that light absorption by dye molecules is saturable at the high illumination intensity, and the saturated absorption signal can be extracted by harmonic demodulation. We obtained the images of a stained rat kidney tissue by selectively detecting the nonlinear transmission signals induced by saturable absorption of the dye molecules. We confirmed the high depth discrimination capability of our technique clearly visualised the fine structures in the specimen that cannot be observed by a conventional laser scanning absorption microscope.


Assuntos
Lasers , Animais , Ratos , Fenômenos Químicos , Microscopia Confocal
7.
Proc Natl Acad Sci U S A ; 115(47): E11178-E11187, 2018 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-30397148

RESUMO

The plant hormone abscisic acid (ABA) is accumulated after drought stress and plays critical roles in the responses to drought stress in plants, such as gene regulation, stomatal closure, seed maturation, and dormancy. Although previous reports revealed detailed molecular roles of ABA in stress responses, the factors that contribute to the drought-stress responses-in particular, regulation of ABA accumulation-remain unclear. The enzyme NINE-CIS-EPOXYCAROTENOID DIOXYGENASE 3 (NCED3) is essential for ABA biosynthesis during drought stress, and the NCED3 gene is highly induced by drought stress. In the present study, we isolated NGATHAs (NGAs) as candidate transcriptional regulators of NCED3 through a screen of a plant library harboring the transcription factors fused to a chimeric repressor domain, SRDX. The NGA proteins were directly bound to a cis-element NGA-binding element (NBE) in the 5' untranslated region (5' UTR) of the NCED3 promoter and were suggested to be transcriptional activators of NCED3 Among the single-knockout mutants of four NGA family genes, we found that the NGATHA1 (NGA1) knockout mutant was drought-stress-sensitive with a decreased expression level of NCED3 during dehydration stress. These results suggested that NGA1 essentially functions as a transcriptional activator of NCED3 among the NGA family proteins. Moreover, the NGA1 protein was degraded under nonstressed conditions, and dehydration stress enhanced the accumulation of NGA1 proteins, even in ABA-deficient mutant plants, indicating that there should be ABA-independent posttranslational regulations. These findings emphasize the regulatory mechanisms of ABA biosynthesis during early drought stress.


Assuntos
Ácido Abscísico/biossíntese , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Dioxigenases/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Proteínas de Plantas/metabolismo , Estresse Fisiológico/genética , Fatores de Transcrição/metabolismo , Regiões 5' não Traduzidas/genética , Ácido Abscísico/genética , Proteínas de Arabidopsis/genética , Dioxigenases/genética , Secas , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Regiões Promotoras Genéticas/genética , Estresse Fisiológico/fisiologia , Fatores de Transcrição/genética , Ativação Transcricional/genética
8.
Int Heart J ; 62(6): 1379-1386, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34853228

RESUMO

Clinical studies have indicated that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, also known as statins, can potentially inhibit chronic heart failure. In the Stat-LVDF study, a difference was noted in terms of the effect of lipophilic pitavastatin (PTV) and hydrophilic rosuvastatin (RSV) on plasma BNP, suggesting that statin lipophilicity and pharmacokinetics change the pleiotropic effect on heart failure in humans. Therefore, we assessed the beneficial effects of PTV on hypertrophy in cardiac myocytes compared with RSV at clinically used doses. Cultured cardiomyocytes were stimulated with 30 µM phenylephrine (PE) in the presence of PTV (250 nM) or RSV (50 nM). These doses were calculated based on the maximum blood concentration of statins used in clinical situations in Japan. The results showed that PTV, but not RSV, significantly inhibits the PE-induced increase in cell size and leucine incorporation without causing cell toxicity. In addition, PTV significantly suppressed PE-induced mRNA expression of hypertrophic response genes. PE-induced ERK phosphorylation was inhibited by PTV, but not by RSV. Furthermore, PTV significantly suppressed the angiotensin-II-induced proline incorporation in primary cultured cardiac fibroblasts. In conclusion, a clinical dose of PTV was noted to directly inhibit cardiomyocyte hypertrophy and cardiac fibrosis, suggesting that lipophilic PTV can be a potential drug candidate against chronic heart failure.


Assuntos
Inibidores de Hidroximetilglutaril-CoA Redutases/administração & dosagem , Miócitos Cardíacos/efeitos dos fármacos , Quinolinas/administração & dosagem , Rosuvastatina Cálcica/administração & dosagem , Actinas/genética , Actinas/metabolismo , Animais , Fator Natriurético Atrial/genética , Fator Natriurético Atrial/metabolismo , Células Cultivadas , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Expressão Gênica , Hipertrofia , Leucina/metabolismo , Peptídeo Natriurético Encefálico/genética , Peptídeo Natriurético Encefálico/metabolismo , Fosforilação/efeitos dos fármacos , RNA Mensageiro/metabolismo , Ratos Sprague-Dawley
9.
Plant Physiol ; 180(3): 1677-1690, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31123093

RESUMO

Functional diversification of transcription factors allows the precise regulation of transcriptomic changes under different environmental conditions. The NUCLEAR FACTOR Y (NF-Y) transcription factor comprises three subunits, NF-YA, NF-YB, and NF-YC, and is broadly diversified in plant species, whereas Humans (Homo sapiens) have one protein for each subunit. However, there remains much to be learned about the diversified functions of each subunit in plants. Here, we found that NF-YB2 and NF-YB3, which have the greatest sequence similarity to each other among NF-YB family proteins in Arabidopsis (Arabidopsis thaliana), are functionally diversified and specifically activate dehydration-inducible and heat-inducible genes, according to environmental conditions. Overexpression of NF-YB2 and NF-YB3 specifically enhanced drought and heat stress tolerance, respectively, and each single knockout mutant showed adverse stress-sensitive phenotypes. Transcriptomic analyses confirmed that overexpression of NF-YB2 and NF-YB3 largely affected the transcriptomic changes under dehydration and heat stress conditions, respectively. The DNA-binding profiles of each protein in planta also suggested that dehydration and heat stress increased the DNA-binding activity of NF-YB2 and NF-YB3 to dehydration-inducible and heat stress-inducible target genes, respectively. Moreover, phylogenetic analysis suggested that the NF-YB proteins of angiosperm plants belong to divergent NF-YB2 and NF-YB3 subgroups. These results demonstrate the functional diversification of NF-Y through evolutionary processes and how plants adapt to various abiotic stresses under fluctuating environments.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Fator de Ligação a CCAAT/genética , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas , Transativadores/genética , Adaptação Fisiológica/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Fator de Ligação a CCAAT/metabolismo , Secas , Variação Genética , Resposta ao Choque Térmico , Fenótipo , Plantas Geneticamente Modificadas , Transativadores/metabolismo
10.
Proc Natl Acad Sci U S A ; 114(40): E8528-E8536, 2017 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-28923951

RESUMO

DEHYDRATION-RESPONSIVE ELEMENT BINDING PROTEIN 2A (DREB2A) acts as a key transcription factor in both drought and heat stress tolerance in Arabidopsis and induces the expression of many drought- and heat stress-inducible genes. Although DREB2A expression itself is induced by stress, the posttranslational regulation of DREB2A, including protein stabilization, is required for its transcriptional activity. The deletion of a 30-aa central region of DREB2A known as the negative regulatory domain (NRD) transforms DREB2A into a stable and constitutively active form referred to as DREB2A CA. However, the molecular basis of this stabilization and activation has remained unknown for a decade. Here we identified BTB/POZ AND MATH DOMAIN proteins (BPMs), substrate adaptors of the Cullin3 (CUL3)-based E3 ligase, as DREB2A-interacting proteins. We observed that DREB2A and BPMs interact in the nuclei, and that the NRD of DREB2A is sufficient for its interaction with BPMs. BPM-knockdown plants exhibited increased DREB2A accumulation and induction of DREB2A target genes under heat and drought stress conditions. Genetic analysis indicated that the depletion of BPM expression conferred enhanced thermotolerance via DREB2A stabilization. Thus, the BPM-CUL3 E3 ligase is likely the long-sought factor responsible for NRD-dependent DREB2A degradation. Through the negative regulation of DREB2A stability, BPMs modulate the heat stress response and prevent an adverse effect of excess DREB2A on plant growth. Furthermore, we found the BPM recognition motif in various transcription factors, implying a general contribution of BPM-mediated proteolysis to divergent cellular responses via an accelerated turnover of transcription factors.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Regiões Promotoras Genéticas , Termotolerância , Fatores de Transcrição/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Desidratação , Resposta ao Choque Térmico , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/metabolismo , Proteólise , Estresse Fisiológico , Ubiquitina-Proteína Ligases/genética
11.
J Nat Prod ; 82(7): 1791-1796, 2019 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-31268714

RESUMO

NFAT-133, isolated from Streptomyces sp., is an immunosuppressive, antidiabetic, and antitrypanosomal aromatic polyketide with three contiguous stereocenters. The first enantioselective total synthesis of the proposed structure of NFAT-133 [(10R,11R,12S)-1] and its C10 epimer [(10S,11R,12S)-1] was achieved from a known aromatic ester (5) by a 10-step sequence that featured chiral auxiliary-directed asymmetric alkylation and the Evans asymmetric aldol reaction as the chirality-inducing steps. The 1H and 13C NMR data as well as the specific rotation value of natural NFAT-133 were not identical to those of the proposed structure, but were in good agreement with those of its C10 epimer. This led us to conclude that the absolute configuration of NFAT-133 should be revised to 10S, 11R, and 12S.


Assuntos
Pentanóis/química , Pentanonas/química , Estrutura Molecular , Pentanóis/síntese química , Pentanonas/síntese química , Análise Espectral/métodos , Estereoisomerismo
12.
Proc Natl Acad Sci U S A ; 113(15): 3986-90, 2016 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-27035956

RESUMO

It is thought that strong electron correlation in an insulating parent phase would enhance a critical temperature (Tc) of superconductivity in a doped phase via enhancement of the binding energy of a Cooper pair as known in high-Tc cuprates. To induce a superconductor transition in an insulating phase, injection of a high density of carriers is needed (e.g., by impurity doping). An electric double-layer transistor (EDLT) with an ionic liquid gate insulator enables such a field-induced transition to be investigated and is expected to result in a high Tc because it is free from deterioration in structure and carrier transport that are in general caused by conventional carrier doping (e.g., chemical substitution). Here, for insulating epitaxial thin films (∼10 nm thick) of FeSe, we report a high Tc of 35 K, which is 4× higher than that of bulk FeSe, using an EDLT under application of a gate bias of +5.5 V. Hall effect measurements under the gate bias suggest that highly accumulated electron carrier in the channel, whose area density is estimated to be 1.4 × 10(15) cm(-2) (the average volume density of 1.7 × 10(21) cm(-3)), is the origin of the high-Tc superconductivity. This result demonstrates that EDLTs are useful tools to explore the ultimate Tc for insulating parent materials.

13.
Sensors (Basel) ; 19(7)2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30939859

RESUMO

A semiconductor array pH image sensor consisting of four separated blocks was fabricated using charged coupled device (CCD) and complementary metal oxide semiconductor (CMOS) technologies. The sensing surface of one of the four blocks was Si3N4 and this block responded to H⁺. The surfaces of the other three blocks were respectively covered with cation sensitive membranes, which were separately printed with plasticized poly (vinyl chloride) solutions including Na⁺, K⁺, and Ca2+ ionophores by using an ink-jet printing method. In addition, each block of the image sensor with 128 × 128 pixels could have a calibration curve generated in each independent measurement condition. The present sensor could measure the concentration image of four kinds of ions (H⁺, K⁺, Na +, Ca2+) simultaneously at 8.3 frames per second (fps) in separated regions on a chip.

14.
Eur J Clin Pharmacol ; 74(11): 1461-1469, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30051214

RESUMO

PURPOSE: Clinical responses to oral tramadol show a large variation in cancer patients. This study aimed to evaluate the impacts of cytochrome P450 (CYP) genotype and serum inflammatory markers on the plasma concentrations of tramadol and its demethylated metabolites and drug tolerability in cancer patients. METHODS: The predose plasma concentrations of tramadol and its demethylated metabolites were determined at day 4 or later in 70 Japanese cancer patients treated with oral tramadol. The CYP genotypes, serum interleukin-6 (IL-6) and C-reactive protein (CRP) levels, and the duration of tramadol treatment were evaluated. RESULTS: The CYP2D6 genotype did not affect the plasma tramadol concentration. The plasma concentration of O-desmethyltramadol and its ratio to tramadol were lower in the CYP2D6 intermediate and poor metabolizer (IM + PM) group than in the normal metabolizer (NM) group (P = 0.002 and P = 0.023). The plasma concentration of N-desmethyltramadol and its ratio to tramadol were higher in the CYP2D6 IM + PM group than in the NM group (P = 0.001 and P = 0.001). The CYP2B6*6 and CYP3A5*3 alleles had no effect on the plasma concentrations of tramadol and its demethylated metabolites. The serum IL-6 and CRP levels were inversely correlated with the plasma concentration ratios of N-desmethyltramadol to tramadol and of N,O-didesmethyltramadol to O-desmethyltramadol. The serum IL-6 level was associated with the treatment duration of oral tramadol. CONCLUSIONS: The CYP2D6 genotype but not the CYP2B6 and CYP3A5 genotypes affected the plasma concentrations of O- and N-desmethyltramadol through alteration of the tramadol metabolic pathway. The serum IL-6 level was associated with N-demethylation activity and tramadol tolerability.


Assuntos
Analgésicos Opioides/administração & dosagem , Citocromo P-450 CYP2D6/genética , Sistema Enzimático do Citocromo P-450/genética , Tramadol/administração & dosagem , Administração Oral , Idoso , Analgésicos Opioides/efeitos adversos , Analgésicos Opioides/farmacocinética , Povo Asiático/genética , Proteína C-Reativa/metabolismo , Dor do Câncer/tratamento farmacológico , Feminino , Genótipo , Humanos , Interleucina-6/sangue , Masculino , Pessoa de Meia-Idade , Neoplasias/tratamento farmacológico , Fatores de Tempo , Tramadol/efeitos adversos , Tramadol/análogos & derivados , Tramadol/farmacocinética
15.
Adv Exp Med Biol ; 1081: 189-214, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30288711

RESUMO

Plant responses to drought stress have been analyzed extensively to reveal complex regulatory gene networks, including the detection of water deficit signals, as well as the physiological, cellular, and molecular responses. Plants recognize water deficit conditions at their roots and transmit this signal to their shoots to synthesize abscisic acid (ABA) in their leaves. ABA is a key phytohormone that regulates physiological and molecular responses to drought stress, such as stomatal closure, gene expression, and the accumulation of osmoprotectants and stress proteins. ABA transporters function as the first step for propagating synthesized ABA. To prevent water loss, ABA influx in guard cells is detected by several protein kinases, such as SnRK2s and MAPKs that regulate stomatal closure. ABA mediates a wide variety of gene expression machineries with stress-responsive transcription factors, including DREBs and AREBs, to acquire drought stress resistance in whole tissues. In this chapter, we summarize recent advances in drought stress signaling, focusing on gene networks in cellular and intercellular stress responses and drought resistance.


Assuntos
Aclimatação , Secas , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Genes de Plantas , Proteínas de Plantas/genética , Plantas/genética , Ácido Abscísico/metabolismo , Desidratação/genética , Estado de Hidratação do Organismo/genética , Desenvolvimento Vegetal , Proteínas de Plantas/metabolismo , Plantas/metabolismo , Transdução de Sinais , Água/metabolismo
16.
Plant Cell ; 26(12): 4954-73, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25490919

RESUMO

DEHYDRATION-RESPONSIVE ELEMENT BINDING PROTEIN2A (DREB2A) is a key transcription factor for drought and heat stress tolerance in Arabidopsis thaliana. DREB2A induces the expression of dehydration- and heat stress-inducible genes under the corresponding stress conditions. Target gene selectivity is assumed to require stress-specific posttranslational regulation, but the mechanisms of this process are not yet understood. Here, we identified DNA POLYMERASE II SUBUNIT B3-1 (DPB3-1), which was previously annotated as NUCLEAR FACTOR Y, SUBUNIT C10 (NF-YC10), as a DREB2A interactor, through a yeast two-hybrid screen. The overexpression of DPB3-1 in Arabidopsis enhanced the expression of a subset of heat stress-inducible DREB2A target genes but did not affect dehydration-inducible genes. Similarly, the depletion of DPB3-1 expression resulted in reduced expression of heat stress-inducible genes. Interaction and expression pattern analyses suggested the existence of a trimer comprising NF-YA2, NF-YB3, and DPB3-1 that could synergistically activate a promoter of the heat stress-inducible gene with DREB2A in protoplasts. These results suggest that DPB3-1 could form a transcriptional complex with NF-YA and NF-YB subunits and that the identified trimer enhances heat stress-inducible gene expression during heat stress responses in cooperation with DREB2A. We propose that the identified trimer contributes to the target gene selectivity of DREB2A under heat stress conditions.


Assuntos
Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/fisiologia , Arabidopsis/fisiologia , DNA Polimerase II/fisiologia , Regulação da Expressão Gênica de Plantas , Resposta ao Choque Térmico/genética , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , DNA Polimerase II/genética , DNA Polimerase II/metabolismo , Técnicas de Silenciamento de Genes , Regiões Promotoras Genéticas , Protoplastos/metabolismo , Técnicas do Sistema de Duplo-Híbrido
17.
Ther Drug Monit ; 39(6): 625-631, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28976420

RESUMO

BACKGROUND: No information on the pharmacokinetic characteristics of amlodipine (AML) metabolites is available. This study aimed to develop a method based on isocratic liquid chromatography coupled to tandem mass spectrometry for the simultaneous determination of AML and its 2 major metabolites, dehydroamlodipine (DH-AML) and O-des[2-aminoethyl]-O-carboxymethyl DH-AML (CM-DH-AML), and to use it for monitoring this drug in hypertensive patients. METHODS: Acetonitrile-deproteinized plasma specimens were separated using an octadecyl-silica column (3-µm particle size) with a mobile phase consisting of 50% methanol containing 0.15% of formic acid in water. The run time was 9 minutes. The mass spectrometer was run in the positive ion electrospray ionization mode. This method was applied for the determination of AML and its metabolites in plasma samples from patients treated with this drug. RESULTS: The calibration curves in human plasma of AML, DH-AML, and CM-DH-AML were linear over the concentration ranges of 0.5-64, 1-64, and 0.5-64 ng/mL, respectively, and their lower limits of quantification were 0.5, 1, and 0.5 ng/mL, respectively. Their extraction recovery rates and matrix factors in human plasma were 94.8%-109.0% and 97.0%-101.4%, respectively. The intra-assay and interassay imprecisions and accuracies were within 10.8% and 95.4%-111.2%, respectively. The plasma concentration ranges of AML, DH-AML, and CM-DH-AML were 6.5-20.9, 1.4-10.9, and 5.6-38.3 ng/mL, respectively. CONCLUSIONS: The present method with acceptable analytical performance can be helpful for monitoring the plasma concentration of AML, including the determination of its metabolites in patients with hypertension.


Assuntos
Anlodipino/sangue , Anlodipino/metabolismo , Cromatografia Líquida/métodos , Hipertensão/sangue , Hipertensão/tratamento farmacológico , Espectrometria de Massas em Tandem/métodos , Anlodipino/química , Anti-Hipertensivos/sangue , Anti-Hipertensivos/química , Anti-Hipertensivos/metabolismo , Humanos , Estrutura Molecular , Sensibilidade e Especificidade
18.
Plant Biotechnol J ; 14(8): 1756-67, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-26841113

RESUMO

The enhancement of heat stress tolerance in crops is an important challenge for food security to facilitate adaptation to global warming. In Arabidopsis thaliana, the transcriptional regulator DNA polymerase II subunit B3-1 (DPB3-1)/nuclear factor Y subunit C10 (NF-YC10) has been reported as a positive regulator of Dehydration-responsive element binding protein 2A (DREB2A), and the overexpression of DPB3-1 enhances heat stress tolerance without growth retardation. Here, we show that DPB3-1 interacts with DREB2A homologues in rice and soya bean. Transactivation analyses with Arabidopsis and rice mesophyll protoplasts indicate that DPB3-1 and its rice homologue OsDPB3-2 function as positive regulators of DREB2A homologues. Overexpression of DPB3-1 did not affect plant growth or yield in rice under nonstress conditions. Moreover, DPB3-1-overexpressing rice showed enhanced heat stress tolerance. Microarray analysis revealed that many heat stress-inducible genes were up-regulated in DPB3-1-overexpressing rice under heat stress conditions. However, the overexpression of DPB3-1 using a constitutive promoter had almost no effect on the expression of these genes under nonstress conditions. This may be because DPB3-1 is a coactivator and thus lacks inherent transcriptional activity. We conclude that DPB3-1, a coactivator that functions specifically under abiotic stress conditions, could be utilized to increase heat stress tolerance in crops without negative effects on vegetative and reproductive growth.


Assuntos
Proteínas de Arabidopsis/genética , DNA Polimerase II/genética , Regulação da Expressão Gênica de Plantas , Glycine max/fisiologia , Oryza/fisiologia , Estresse Fisiológico/genética , Proteínas de Arabidopsis/metabolismo , Fator de Ligação a CCAAT/genética , DNA Polimerase II/metabolismo , Oryza/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Protoplastos , Glycine max/genética , Fatores de Transcrição/genética
19.
Eur J Clin Pharmacol ; 72(12): 1463-1470, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27566315

RESUMO

PURPOSE: Elevated serum proinflammatory cytokines are associated with the reduction of cytochrome P450 enzyme (CYP) activity. This study aimed to evaluate the oxycodone pharmacokinetics, central symptoms, and serum proinflammatory cytokines based on cachexia stage in cancer patients. METHODS: Forty-seven cancer patients receiving extended-release oxycodone were enrolled. Predose plasma concentrations of oxycodone and its metabolites were normalized with the daily dose and body weight. The central symptoms and serum level of proinflammatory cytokines were investigated at each cachexia stage. RESULTS: The plasma concentrations of oxycodone in patients with cachexia and refractory cachexia were significantly higher than that in patients with precachexia. The metabolic ratio to noroxycodone in patients with cachexia was significantly lower than that in patients with precachexia. The patients with a higher cachexia stage had a higher serum level of interleukin-6 (IL-6), but not tumor necrosis factor-α and interleukin-1ß. The serum IL-6 level was correlated with the plasma concentration of oxycodone and inversely with the metabolic ratio to noroxycodone. The incidence of somnolence was not associated with the plasma oxycodone concentration. In contrast, the cachexia stage and its associated serum IL-6 level were correlated with the incidence of somnolence. CONCLUSIONS: Cancer cachexia raised the plasma exposure of oxycodone through the reduction of CYP3A metabolic pathway. The reduction of CYP3A in cachectic cancer patients was associated with an elevation of serum IL-6. Although cachectic cancer patients with higher serum IL-6 levels had the symptom of somnolence, the alterations in oxycodone pharmacokinetics were not related to the incidence of symptom.


Assuntos
Analgésicos Opioides/farmacocinética , Caquexia/sangue , Citocromo P-450 CYP3A/metabolismo , Interleucina-6/sangue , Oxicodona/farmacocinética , Idoso , Analgésicos Opioides/efeitos adversos , Analgésicos Opioides/sangue , Caquexia/tratamento farmacológico , Preparações de Ação Retardada/farmacocinética , Delírio/induzido quimicamente , Depressão/induzido quimicamente , Distúrbios do Sono por Sonolência Excessiva/induzido quimicamente , Feminino , Humanos , Interleucina-1beta/sangue , Masculino , Pessoa de Meia-Idade , Neoplasias/sangue , Neoplasias/tratamento farmacológico , Oxicodona/efeitos adversos , Oxicodona/sangue , Fator de Necrose Tumoral alfa/sangue
20.
iScience ; 27(2): 108855, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38318384

RESUMO

The subnuclear distribution of centromeres is cooperatively regulated by condensin II and the linker of nucleoskeleton and cytoskeleton (LINC) complex. However, other nuclear membrane structures and nuclear proteins are probably involved in centromere dynamics and distribution. Here, we focused on the nuclear pore complex (NPC), which is known to regulate gene expression, transcription memory, and chromatin structure in addition to transport between the cytoplasm and nucleoplasm. We report here that some nucleoporins (Nups), including Nup85, Nup133, CG1, Nup93b, and NUA, are involved in centromere scattering in Arabidopsis thaliana. In addition, the centromere dynamics after metaphase in nup mutants were found to be similar to that of the condensin II mutant. Furthermore, both biochemical and genetic approaches showed that the Nups interact with the LINC complex. These results suggest that Nups regulate centromere scattering cooperatively with condensin II and the LINC complex.

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