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1.
Int Heart J ; 62(2): 298-304, 2021 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-33731524

RESUMO

Radiofrequency and cryoballoon applications around the pulmonary veins (PVs) could provoke a vagal reflex (VR) by modulating the intrinsic cardiac autonomic nervous system (ICANS).This study aimed to investigate the incidence, timing, and clinical impact of a VR provoked by a laser balloon application for a PV isolation (PVI).A total of 92 consecutive paroxysmal atrial fibrillation (PAF) patients underwent a laser balloon PVI of PAF. Acute changes in the heart rate and blood pressure were recorded. The heart rate variability (HRV) was tested by Holter ECGs before and at three months following the ablation. Three hundred forty-five out of 363 PVs were successfully isolated (97%) with laser balloon applications. A VR such as sinus bradycardia (26.1%), transient sinus arrest (9.8%), transient atrioventricular block (1.1%), or a blood pressure reduction (8.7%) was observed during the laser balloon applications for the PVI. The follow-up ended at 12 months. The HRV attenuation was comparable before and at three months after the ablation procedure between that with and without a VR (P = 0.14). The PAF recurrence rate was also comparable between the two groups (P = 0.882).The laser balloon PVI often provoked a VR, however, the modulation of the ICANS was temporary and for up to three months as measured by the HRV changes after the ablation, and the freedom from any atrial fibrillation recurrence was comparable regardless of the occurrence of a VR.


Assuntos
Fibrilação Atrial/cirurgia , Ablação por Cateter/métodos , Frequência Cardíaca/fisiologia , Terapia a Laser/métodos , Taquicardia Paroxística/cirurgia , Nervo Vago/fisiopatologia , Idoso , Fibrilação Atrial/fisiopatologia , Eletrocardiografia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Taquicardia Paroxística/fisiopatologia , Fatores de Tempo
2.
Soft Matter ; 16(18): 4549-4554, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32364199

RESUMO

Membrane adhesion is a ubiquitous phenomenon in cells and is related to various biological events such as migration, morphogenesis, and differentiation. To understand the physicochemical aspects of membrane adhesion, liposome-liposome adhesion and liposome-substrate adhesion have been studied. Although membrane adhesion has been shown to increase membrane tension and inhibit lipid diffusion, the relationship between these changes and the degree of membrane adhesion have not been quantified. Here, we analyzed the dependence of membrane tension and lipid diffusion on the degree of membrane adhesion, i.e., area fraction of the adherent region. For this purpose, we developed a simple method to prepare adhered liposomes by simple electrostatic interactions between the membranes and by osmotic deflation. We found that the membrane tension of the adhered liposomes increases slightly with an increase in the area fraction of the adherent region. In addition, the lipid diffusion coefficient of the adhered liposomes is larger than that of isolated liposomes, which is consistent with the theoretical prediction. The analysis provides a framework to understand the correlation between cell adhesion and bio-membrane properties such as membrane tension and molecular diffusion.


Assuntos
Bicamadas Lipídicas/química , Lipossomos/química , Difusão , Membranas Artificiais , Osmose , Eletricidade Estática
3.
Int Heart J ; 61(2): 249-253, 2020 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-32173706

RESUMO

Cryoballoon ablation is an established catheter-based approach to treat atrial fibrillation (AF). However, thromboembolic events cannot be avoided during cryoablation. There is little data regarding the blood coagulation status during freezing.The thrombin antithrombin complex (TAT) and prothrombin fragment 1+2 (F 1+2) of patient blood were measured during cryoballoon application when the cryoballoon temperature reached the nadir in 63 AF patients. TAT was also measured from porcine blood during cryoballoon freezing in 5 pigs.The TAT and F 1+2 increased from 6.60 ± 5.65 to 9.16 ± 7.28 ng/mL (P = 0.004) and from 279.6 ± 146.4 to 323.6 ± 169.1 pmol/L (P = 0.003) between the control and during freezing, respectively. The TAT increased from 0.46 to 0.87 ng/mL during freezing compared to that of pre-freezing (P < 0.05), and it returned to 0.39 ng/mL in 30 minutes after an intravenous edoxaban administration (N.S.).Dabigatran failed to exert sufficient anticoagulant effects during cryofreezing. In contrast, intravenous edoxaban seemed to provoke anticoagulation effects under extreme low temperature circumstances.


Assuntos
Antitrombinas/uso terapêutico , Criocirurgia/efeitos adversos , Dabigatrana/uso terapêutico , Piridinas/uso terapêutico , Tiazóis/uso terapêutico , Tromboembolia/etiologia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tromboembolia/prevenção & controle
4.
Biotechnol Bioeng ; 116(11): 3136-3142, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31369146

RESUMO

Three-dimensional (3D) printers are attracting attention as a method for arranging and building cells in three dimensions. Bioprinting technology has potential in tissue engineering for the fabrication of scaffolds, cells, and tissues. However, these various printing technologies have limitations with respect to print resolution and due to the characteristics of bioink such as viscosity. We report a method for constructing of 3D tissues with a "microscopic painting device using a painting needle method" that, when used with the layer-by-layer (LbL) cell coating technique, replaces conventional methods. This method is a technique of attaching the high viscosity bioink to the painting needle tip and arranging it on a substrate, and can construct 3D tissues without damage to cells. Cell viability is the same before and after painting. We used this biofabrication device to construct 3D cardiac tissue (LbL-3D Heart) using human-induced pluripotent stem cell-derived cardiomyocytes. The constructed LbL-3D Heart chips had multiple layers with a thickness of 60 µm, a diameter of 1.1 mm, and showed synchronous beating (50-60 beats per min). The aforementioned device and method of 3D tissue construction can be applied to various kinds of tissue models and would be a useful tool for pharmaceutical applications.


Assuntos
Bioimpressão , Células-Tronco Pluripotentes Induzidas/metabolismo , Miocárdio/metabolismo , Agulhas , Impressão Tridimensional , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Miocárdio/citologia
6.
J Phys Ther Sci ; 31(8): 670-674, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31528007

RESUMO

[Purpose] This study aimed to examine the impact of changing the drop vertical jump stance time on kinematic and kinetic parameters by ordering to high jump or quick jump for consistent stance time and a more accurate assessment of anterior cruciate ligament injury risk. [Participants and Methods] The participants were 20 healthy female students. The drop vertical jump was started by instructing the participants to stand on a 30-cm platform with both legs stationary. The task was performed while the participants were instructed to perform high jump or quick jump. [Results] Stance time was significantly shorter with quick jump than with high jump. Quick jump showed significantly higher knee abduction angles at initial contact and peak vertical ground reaction force, and lower hip flexion, knee flexion, and ankle dorsiflexion angles at the lowest point of the center of mass. Quick jump showed a significantly higher peak vertical ground reaction force. The knee abduction moment at initial contact was not significantly different between the 2 conditions. [Conclusion] Quick jump was better than high jump for making stance time consistent, and the differences in kinematic and kinetic characteristics by oral instructions should be considered when using drop vertical jump.

7.
Sensors (Basel) ; 18(12)2018 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-30544609

RESUMO

Land cover classification and investigation of temporal changes are considered to be common applications of remote sensing. Water/non-water region estimation is one of the most fundamental classification tasks, analyzing the occurrence of water on the Earth's surface. However, common remote sensing practices such as thresholding, spectral analysis, and statistical approaches are not sufficient to produce a globally adaptable water classification. The aim of this study is to develop a formula with automatically derived tuning parameters using perceptron neural networks for water/non-water region estimation, which we call the Perceptron-Derived Water Formula (PDWF), using Landsat-8 images. Water/non-water region estimates derived from PDWF were compared with three different approaches-Modified Normalized Difference Water Index (MNDWI), Automatic Water Extraction Index (AWEI), and Deep Convolutional Neural Network-using various case studies. Our proposed method outperforms all three approaches, showing a significant improvement in water/non-water region estimation. PDWF performance is consistently better even in cases of challenging conditions such as low reflectance due to hill shadows, building-shadows, and dark soils. Moreover, our study implemented a sunglint correction to adapt water/non-water region estimation over sunglint-affected pixels.

8.
J Phys Ther Sci ; 29(2): 187-190, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28265136

RESUMO

[Purpose] To investigate the features of backward walking in stroke patients with hemiplegia by focusing on the joint movements and moments of the paretic side, walking speed, stride length, and cadence. [Subjects and Methods] Nine stroke patients performed forward walking and backward walking along a 5-m walkway. Walking speed and stride length were self-selected. Movements were measured using a three-dimensional motion analysis system and a force plate. One walking cycle of the paretic side was analyzed. [Results] Walking speed, stride length, and cadence were significantly lower in backward walking than in forward walking. Peak hip extension was significantly lower in backward walking and peak hip flexion moment, knee extension moment, and ankle dorsiflexion and plantar flexion moments were lower in backward walking. [Conclusion] Unlike forward walking, backward walking requires conscious hip joint extension. Conscious extension of the hip joint is hard for stroke patients with hemiplegia. Therefore, the range of hip joint movement declined in backward walking, and walking speed and stride length also declined. The peak ankle plantar flexion moment was significantly lower in backward walking than in forward walking, and it was hard to generate propulsion power in backward walking. These difficulties also affected the walking speed.

9.
J Phys Ther Sci ; 29(10): 1860-1864, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29184307

RESUMO

[Purpose] The purpose of this study was to investigate whether transcutaneous electrical nerve stimulation simultaneously combined with local heat and cold applications enhances pain relief compared with transcutaneous electrical nerve stimulation alone in patients with knee osteoarthritis. [Subjects and Methods] Fourty-five patients with knee osteoarthritis participated in this study. They were randomly assigned to the following three interventions: transcutaneous electrical nerve stimulation simultaneously combined with local heat using a hot pack; combined with local cold using a cold pack; and transcutaneous electrical nerve stimulation alone. In each intervention, the knee pain level during walking and standing up from a chair, as well as dynamic balance and gait ability were evaluated immediately before and after a single intervention using the visual analogue scale and the timed up & go test, respectively. [Results] A significant improvement in dynamic balance and gait ability was only observed immediately after transcutaneous electrical nerve stimulation simultaneously combined with local heat application, although the degree of pain relief during standing and walking were comparable among the three interventions. [Conclusion] These results suggest that transcutaneous electrical nerve stimulation simultaneously combined with local heat application can immediately improve not only knee pain during standing and walking but also dynamic balance and gait ability in patients with knee osteoarthritis.

10.
Proc Natl Acad Sci U S A ; 110(42): 17137-42, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24082137

RESUMO

Photoperiodic floral induction has had a significant impact on the agricultural and horticultural industries. Changes in day length are perceived in leaves, which synthesize systemic flowering inducers (florigens) and inhibitors (antiflorigens) that determine floral initiation at the shoot apex. Recently, FLOWERING LOCUS T (FT) was found to be a florigen; however, the identity of the corresponding antiflorigen remains to be elucidated. Here, we report the identification of an antiflorigen gene, Anti-florigenic FT/TFL1 family protein (AFT), from a wild chrysanthemum (Chrysanthemum seticuspe) whose expression is mainly induced in leaves under noninductive conditions. Gain- and loss-of-function analyses demonstrated that CsAFT acts systemically to inhibit flowering and plays a predominant role in the obligate photoperiodic response. A transient gene expression assay indicated that CsAFT inhibits flowering by directly antagonizing the flower-inductive activity of CsFTL3, a C. seticuspe ortholog of FT, through interaction with CsFDL1, a basic leucine zipper (bZIP) transcription factor FD homolog of Arabidopsis. Induction of CsAFT was triggered by the coincidence of phytochrome signals with the photosensitive phase set by the dusk signal; flowering occurred only when night length exceeded the photosensitive phase for CsAFT induction. Thus, the gated antiflorigen production system, a phytochrome-mediated response to light, determines obligate photoperiodic flowering response in chrysanthemums, which enables their year-round commercial production by artificial lighting.


Assuntos
Chrysanthemum/metabolismo , Flores/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Fotoperíodo , Proteínas de Plantas/biossíntese , Transativadores/biossíntese , Sequência de Aminoácidos , Chrysanthemum/genética , Flores/genética , Loci Gênicos/fisiologia , Dados de Sequência Molecular , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Homologia de Sequência de Aminoácidos , Transativadores/genética
11.
Semin Cell Dev Biol ; 24(4): 308-13, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23499790

RESUMO

The actin cytoskeleton is critically involved in a variety of cell functions. The Arp2/3 complex mediates branching of filamentous actin. The members of the Wiskott-Aldrich syndrome protein (WASP) family are major regulators of the complex. As such, the family proteins are also involved in numerous aspects of cell biology. In this short review, we first define the expanding WASP family. Next, we compare the domain structure of the members, and explain the known or proposed functions of each domain or region. Finally, we demonstrate the well-characterized roles of the proteins in specific cellular functions.


Assuntos
Proteínas do Citoesqueleto/fisiologia , Família de Proteínas da Síndrome de Wiskott-Aldrich/fisiologia , Citoesqueleto de Actina/metabolismo , Citoesqueleto de Actina/fisiologia , Animais , Proteínas do Citoesqueleto/metabolismo , Humanos , Família de Proteínas da Síndrome de Wiskott-Aldrich/metabolismo
12.
J Exp Bot ; 63(3): 1461-77, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22140240

RESUMO

Chrysanthemum is a typical short-day (SD) plant that responds to shortening daylength during the transition from the vegetative to the reproductive phase. FLOWERING LOCUS T (FT)/Heading date 3a (Hd3a) plays a pivotal role in the induction of phase transition and is proposed to encode a florigen. Three FT-like genes were isolated from Chrysanthemum seticuspe (Maxim.) Hand.-Mazz. f. boreale (Makino) H. Ohashi & Yonek, a wild diploid chrysanthemum: CsFTL1, CsFTL2, and CsFTL3. The organ-specific expression patterns of the three genes were similar: they were all expressed mainly in the leaves. However, their response to daylength differed in that under SD (floral-inductive) conditions, the expression of CsFTL1 and CsFTL2 was down-regulated, whereas that of CsFTL3 was up-regulated. CsFTL3 had the potential to induce early flowering since its overexpression in chrysanthemum could induce flowering under non-inductive conditions. CsFTL3-dependent graft-transmissible signals partially substituted for SD stimuli in chrysanthemum. The CsFTL3 expression levels in the two C. seticuspe accessions that differed in their critical daylengths for flowering closely coincided with the flowering response. The CsFTL3 expression levels in the leaves were higher under floral-inductive photoperiods than under non-inductive conditions in both the accessions, with the induction of floral integrator and/or floral meristem identity genes occurring in the shoot apexes. Taken together, these results indicate that the gene product of CsFTL3 is a key regulator of photoperiodic flowering in chrysanthemums.


Assuntos
Chrysanthemum/metabolismo , Chrysanthemum/fisiologia , Flores/metabolismo , Flores/fisiologia , Fotoperíodo , Proteínas de Plantas/metabolismo , Chrysanthemum/genética , Flores/genética , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Proteínas de Plantas/genética
13.
J Exp Bot ; 62(8): 2731-44, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21296763

RESUMO

The photoperiodic response is one of the adaptation mechanisms to seasonal changes of lengths of day and night. The circadian clock plays pivotal roles in this process. In Arabidopsis, LHY, CCA1, ELF3, and other clock proteins play major roles in maintaining circadian rhythms. lhy;cca1 double mutants with severe defects in circadian rhythms showed accelerated flowering under short days (SDs), but delayed flowering under continuous light (LL). The protein level of the floral repressor SVP increased in lhy;cca1 mutants under LL, and the late-flowering phenotype of lhy;cca1 mutants was partially suppressed by svp, flc, or elf3. ELF3 interacted with both CCA1 and SVP, and elf3 suppressed the SVP accumulation in lhy;cca1 under LL. These results suggest that the unique mechanism of the inversion of the flowering response of lhy;cca1 under LL may involve both the ELF3-SVP/FLC-dependent and -independent pathways. In this work, elf3-1 seeds were mutagenized with heavy-ion beams and used to identify mutation(s) that delayed flowering under LL but not long days (LDs) or SDs even without ELF3. In this screening, seven candidate lines named suppressor of elf3 1 (self1), sel3, sel5, sel7, sel14, sel15, and sel20 were identified. Genetic analysis indicated that sel20 was a new deletion allele of a mutation in the blue light receptor, CRY2. A late-flowering phenotype and decrease of FT expression in the elf3;sel20 double mutant was obvious under LL but not under SDs or LDs. These results indicated that the late-flowering phenotype in the double mutant elf3;sel20 as well as in lhy;cca1 was affected by the presence of darkness. The results suggest that CRY2 may play more essential roles in the acceleration of flowering under LL than LDs or SDs.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Criptocromos/genética , Flores/fisiologia , Luz , Mutação/genética , Fotoperíodo , Fatores de Transcrição/genética , Alelos , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/metabolismo , Flores/genética , Flores/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Genes de Plantas/genética , Genes Supressores , Hipocótilo/crescimento & desenvolvimento , Hipocótilo/efeitos da radiação , Modelos Biológicos , Fenótipo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Supressão Genética/efeitos da radiação , Fatores de Tempo
14.
J Cell Biol ; 173(4): 571-85, 2006 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-16702231

RESUMO

WAVE2 activates the actin-related protein (Arp) 2/3 complex for Rac-induced actin polymerization during lamellipodium formation and exists as a large WAVE2 protein complex with Sra1/PIR121, Nap1, Abi1, and HSPC300. IRSp53 binds to both Rac and Cdc42 and is proposed to link Rac to WAVE2. We found that the knockdown of IRSp53 by RNA interference decreased lamellipodium formation without a decrease in the amount of WAVE2 complex. Localization of WAVE2 at the cell periphery was retained in IRSp53 knockdown cells. Moreover, activated Cdc42 but not Rac weakened the association between WAVE2 and IRSp53. When we measured Arp2/3 activation in vitro, the WAVE2 complex isolated from the membrane fraction of cells was fully active in an IRSp53-dependent manner but WAVE2 isolated from the cytosol was not. Purified WAVE2 and purified WAVE2 complex were activated by IRSp53 in a Rac-dependent manner with PIP(3)-containing liposomes. Therefore, IRSp53 optimizes the activity of the WAVE2 complex in the presence of activated Rac and PIP(3).


Assuntos
Actinas/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Fosfatos de Fosfatidilinositol/metabolismo , Pseudópodes/metabolismo , Família de Proteínas da Síndrome de Wiskott-Aldrich/metabolismo , Proteínas rac de Ligação ao GTP/metabolismo , Complexo 2-3 de Proteínas Relacionadas à Actina/metabolismo , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Citosol/metabolismo , Ativação Enzimática/fisiologia , Humanos , Lipossomos/metabolismo , Proteínas do Tecido Nervoso/genética , Polímeros , Ligação Proteica/fisiologia , Transporte Proteico/fisiologia , Pseudópodes/ultraestrutura , Interferência de RNA , Frações Subcelulares/metabolismo , Proteína cdc42 de Ligação ao GTP/genética , Proteína cdc42 de Ligação ao GTP/metabolismo
15.
Environ Health Prev Med ; 16(4): 247-52, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21431790

RESUMO

OBJECTIVE: The metabolic syndrome is an important social problem affecting many people in developed countries. Obesity is a leading cause of this syndrome, hence understanding molecular mechanisms underlying obesity is of prime importance for preventive medicine to develop novel methods to alleviate the corresponding social cost as well as for pharmaceutical companies to develop antimetabolic drugs. METHODS: Since adipocytes play an important role in obesity, we explored the signaling pathways leading to differentiation of adipocytes. We used a preadipocyte cell line to monitor the differentiation of adipocytes, and virus-mediated gene transfer to assess the role of the transcription factor Stat5 in adipogenesis. Adipocyte differentiation was assessed by Northern blot and Western blot analyses as well as accumulation of fat droplets in cells. Promoter activity of the proadipogenic transcription factor peroxisome proliferator-activated receptor-gamma (PPARγ) was evaluated by luciferase assay. RESULTS: Virus-mediated gene transfer of the constitutively active form of both Stat5A and Stat5B resulted in enhanced adipocyte differentiation in the absence of fetal bovine serum (FBS) as judged by expression of proadipogenic factors as well as accumulation of fat droplets in cells. Such a proadipogenic effect of Stat5 is, in part, mediated by its ability to enhance transcription of PPARγ, a master transcriptional regulator in adipogenesis. CONCLUSION: The constitutively active form of Stat5A and Stat5B promoted adipocyte differentiation in the absence of FBS via induction of PPARγ.


Assuntos
Adipócitos/fisiologia , Adipogenia , PPAR gama/metabolismo , Fator de Transcrição STAT5/metabolismo , Células 3T3-L1 , Adipócitos/citologia , Animais , Sangue Fetal , Humanos , Camundongos , Transfecção
16.
Biomed Mater ; 16(2): 025017, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33445157

RESUMO

In this study, three-dimensional (3D) cardiac tissue constructed using the pin type bioprinter 'microscopic painting device' and layer-by-layer cell coating technique was confirmed to have drug responsiveness by three different analytical methods for cardiotoxicity assay. Recently, increasing attention has been focused on biofabrication to create biomimetic 3D tissue. Although various tissues can be produced in vitro, there are many issues surrounding the stability and reproducibility of the preparation of 3D tissues. Thus, although many bioprinters have been developed, none can efficiently, reproducibly and precisely produce small 3D tissues (µm-mm order) such as spheroids, which are most commonly used in drug development. The 3D cardiac tissue chips were successfully constructed with a similar number of cells as conventional 2D tissue using a pin type bioprinter, and corresponding drug-induced cardiotoxicities were obtained with known compounds that induce cardiotoxicity. The 3D cardiac tissue chips displayed uniform cell density and completely synchronized electrophysiological properties as compared to 2D tissue. The 3D tissues constructed using a pin type bioprinter as a biofabrication device would be promising tools for cardiotoxicity assay as they are capable of obtaining stable and reproducible data, which cannot be obtained by 2D tissue.


Assuntos
Biomimética , Bioimpressão , Cardiotoxicidade , Técnicas de Cultura de Células , Coração/fisiologia , Coração/fisiopatologia , Impressão Tridimensional , Cálcio/metabolismo , Contagem de Células , Diferenciação Celular , Descoberta de Drogas , Desenho de Equipamento , Fibroblastos/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Reprodutibilidade dos Testes
17.
Plant Sci ; 293: 110417, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32081265

RESUMO

Chrysanthemum is a typical short day (SD) flowering plant that requires a longer night period than a critical minimum duration to successfully flower. We identified FLOWERING LOCUS T-LIKE 3 (FTL3) and ANTI-FLORIGENIC FT/TFL1 FAMILY PROTEIN (AFT) as a florigen and antiflorigen, respectively, in a wild diploid chrysanthemum (Chrysanthemum seticuspe). Expression of the genes that produce these proteins, CsFTL3 and CsAFT, is induced in the leaves under SD or a noninductive photoperiod, respectively, and the balance between them determines the progression of floral transition and anthesis. However, how CsFTL3 and CsAFT are regulated to define the critical night length for flowering in chrysanthemum is unclear. In this study, we focused on the circadian clock-related gene GIGANTEA (GI) of C. seticuspe (CsGI) and generated transgenic C. seticuspe plants overexpressing CsGI (CsGI-OX). Under a strongly inductive SD (8 L/16D) photoperiod, floral transition occurred at almost the same time in both wild-type and CsGI-OX plants. However, under a moderately inductive (12 L/12D) photoperiod, the floral transition in CsGI-OX plants was strongly suppressed, suggesting that the critical night length for flowering was lengthened for CsGI-OX plants. Under the 12 L/12D photoperiod, CsAFT was upregulated in CsGI-OX plants. Giving a night break (NB) 10 h after dusk was the most effective time to inhibit flowering in wild-type plants, while the most effective time for NB was extended to dawn (12 and 14 h after dusk) in CsGI-OX plants. In wild-type plants, a red-light pulse delivered 8 or 10 h after dusk induced maximal CsAFT expression, but the length of the time period over which CsAFT could be induced by red light was extended until subjective dawn in CsGI-OX plants. Therefore, CsGI-OX plants required a longer dark period to maintain lower levels of CsAFT, and their critical night length for flowering was thus lengthened. These results suggested that CsGI has an important role in the control of photoperiodic flowering through shaping the gate for CsAFT induction by light in chrysanthemum.


Assuntos
Chrysanthemum/metabolismo , Florígeno/metabolismo , Proteínas de Plantas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Chrysanthemum/genética , Relógios Circadianos/genética , Relógios Circadianos/fisiologia , Flores , Regulação da Expressão Gênica de Plantas , Luz , Fenótipo , Fotoperíodo , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/metabolismo
18.
New Phytol ; 182(4): 838-850, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19383102

RESUMO

Circadian clock proteins play key roles in adaptations of plants to diurnal environmental conditions. The photoperiodic flowering response is one of the mechanisms of adaptation to seasonal changes in the lengths of day and night. Double mutations in two clock genes, late elongated hypocotyl (LHY) and circadian clock associated 1 (CCA1), accelerated flowering under short days (SDs) but delayed flowering under continuous light (LL) in Arabidopsis thaliana. The mechanism underlying the late flowering of lhy;cca1 mutants under LL was investigated here. Late flowering of plants with overexpression of short vegetative phase (SVP) was much more pronounced under SDs and enhanced by constans 2 (co-2) under long days (LDs), suggesting that SVP and CO act independently in the photoperiodic flowering pathway. However, how SVP and flowering locus C (FLC) mediated the effects of LHY/CCA1 and thus influenced flowering time was not completely clear. A mutant line lhy;cca1 in the Landsberg erecta (Ler) background was established, ethyl methanesulfonate (EMS)-mutagenized and used to screen suppressors of late flowering of lhy;cca1 under LL. Mutations in the clock gene early flowering 3 (ELF3) were identified as suppressors. Overexpression and loss-of-function of ELF3 influenced SVP protein accumulation. Therefore, we propose that, as well as the classical GIGANTEA (GI)-CO pathway, LHY/CCA1 regulates a pathway negatively controlling flowering locus T (FT), possibly via ELF3-SVP/FLC.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Relógios Circadianos , Proteínas de Ligação a DNA/metabolismo , Flores/fisiologia , Fatores de Transcrição/metabolismo , Alelos , Arabidopsis/genética , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Relógios Circadianos/genética , Relógios Circadianos/efeitos da radiação , Flores/genética , Flores/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Genes Supressores , Luz , Modelos Biológicos , Mutação/genética , Fenótipo , Supressão Genética/efeitos da radiação , Fatores de Tempo , Fatores de Transcrição/genética , Técnicas do Sistema de Duplo-Híbrido
19.
FASEB J ; 22(7): 2223-31, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18323403

RESUMO

The ectopic expression of the Notch receptor ligand delta-like 1 on stromal cells allows the induction of T cells from embryonic stem cells (ESCs). However, these in vitro-generated T cells are not transplantable because they are too immature to mount an immune response in an immunocompromised animal. We efficiently generated a subset of T cells called invariant natural killer T (iNKT) cells from ESCs derived from peripheral iNKT cells using somatic cell nuclear transfer (ntESCs). These iNKT cells matured autonomously in vivo and exhibited an adjuvant effect accompanying the production of interferon-gamma in an antigen-specific manner. This adjuvant effect culminated in the inhibition of inoculated tumor cell growth. Our results indicate that ntESC-derived iNKT cells are transplantable lymphocytes that will be beneficial for the induction of immune tolerance and the treatment of autoimmune diseases, tumors, and infections.


Assuntos
Núcleo Celular/imunologia , Células-Tronco Embrionárias/imunologia , Células Matadoras Naturais/imunologia , Animais , Complexo CD3/genética , Proteínas de Ligação a DNA/genética , Células-Tronco Embrionárias/citologia , Fator de Transcrição GATA3/genética , Humanos , Proteínas Nucleares/genética , Técnicas de Transferência Nuclear , Receptores de Interleucina-7/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
20.
Eur J Haematol ; 82(3): 223-30, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19018864

RESUMO

The Wiskott-Aldrich syndrome protein (WASP), which is defective in Wiskott-Aldrich syndrome (WAS) patients, is an intracellular protein expressed in non-erythroid hematopoietic cells. Previously, we have established methods to detect intracellular WASP expression in peripheral blood mononuclear cells (PBMNCs) using flow cytometric analysis (FCM-WASP) and have revealed that WAS patients showed absent or very low level intracellular WASP expression in lymphocytes and monocytes, while a significant amount of WASP was detected in those of normal individuals. We applied these methods for diagnostic screening of WAS patients and WAS carriers, as well as to the evaluation of mixed chimera in WAS patients who had previously undergone hematopoietic stem cell transplantation. During these procedures, we have noticed that lymphocytes from normal control individuals showed dual positive peaks, while their monocytes invariably showed a single sharp WASP-positive peak. To investigate the basis of the dual positive peaks (WASP(low-bright) and WASP(high-bright)), we characterized the constituent linage lymphocytes of these two WASP-positive populations. As a result, we found each WASP(low/high) population comprised different linage PBMNCs. Furthermore, we propose that the difference between the two WASP-positive peaks did not result from any difference in WASP expression in the cells, but rather from a difference in the structural and functional status of the WASP protein in the cells. It has been shown that WASP may exist in two forms; an activated or inactivated form. Thus, the structural and functional WASP status or configuration could be evaluated by flow cytometric analysis.


Assuntos
Citometria de Fluxo/métodos , Leucócitos Mononucleares/metabolismo , Proteína da Síndrome de Wiskott-Aldrich/sangue , Proteína da Síndrome de Wiskott-Aldrich/química , Anticorpos/imunologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linhagem da Célula/imunologia , Regulação da Expressão Gênica/genética , Humanos , Leucócitos Mononucleares/química , Ativação Linfocitária/imunologia , RNA Mensageiro/genética , Fatores de Tempo , Proteína da Síndrome de Wiskott-Aldrich/genética , Proteína da Síndrome de Wiskott-Aldrich/imunologia
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