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Objective. The incidence of stroke rising, leading to an increased demand for rehabilitation services. Literature has consistently shown that early and intensive rehabilitation is beneficial for stroke patients. Robot-assisted devices have been extensively studied in this context, as they have the potential to increase the frequency of therapy sessions and thereby the intensity. Robot-assisted systems can be combined with electrical stimulation (ES) to further enhance muscle activation and patient compliance. The objective of this study was to review the effectiveness of ES combined with all types of robot-assisted technology for lower extremity rehabilitation in stroke patients.Approach. A thorough search of peer-reviewed articles was conducted. The quality of the included studies was assessed using a modified version of the Downs and Black checklist. Relevant information regarding the interventions, devices, study populations, and more was extracted from the selected articles.Main results. A total of 26 articles were included in the review, with 23 of them scoring at least fair on the methodological quality. The analyzed devices could be categorized into two main groups: cycling combined with ES and robots combined with ES. Overall, all the studies demonstrated improvements in body function and structure, as well as activity level, as per the International Classification of Functioning, Disability, and Health model. Half of the studies in this review showed superiority of training with the combination of robot and ES over robot training alone or over conventional treatment.Significance. The combination of robot-assisted technology with ES is gaining increasing interest in stroke rehabilitation. However, the studies identified in this review present challenges in terms of comparability due to variations in outcome measures and intervention protocols. Future research should focus on actively involving and engaging patients in executing movements and strive for standardization in outcome values and intervention protocols.
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Extremidad Inferior , Robótica , Rehabilitación de Accidente Cerebrovascular , Humanos , Rehabilitación de Accidente Cerebrovascular/métodos , Rehabilitación de Accidente Cerebrovascular/instrumentación , Robótica/métodos , Robótica/instrumentación , Accidente Cerebrovascular/fisiopatología , Accidente Cerebrovascular/terapia , Terapia por Estimulación Eléctrica/métodos , Terapia por Estimulación Eléctrica/instrumentaciónRESUMEN
OBJECTIVE: Electroconvulsive therapy (ECT) is the most effective treatment for patients with severe major depressive disorder (MDD). Given the known sex differences in MDD, improved knowledge may provide more sex-specific recommendations in clinical guidelines and improve outcome. In the present study we examine sex differences in ECT outcome and its predictors. METHODS: Clinical data from 20 independent sites participating in the Global ECT-MRI Research Collaboration (GEMRIC) were obtained for analysis, totaling 500 patients with MDD (58.6 % women) with a mean age of 54.8 years. Severity of depression before and after ECT was assessed with validated depression scales. Remission was defined as a HAM-D score of 7 points or below after ECT. Variables associated with remission were selected based on literature (i.e. depression severity at baseline, age, duration of index episode, and presence of psychotic symptoms). RESULTS: Remission rates of ECT were independent of sex, 48.0 % in women and 45.7 % in men (X2(1) = 0.2, p = 0.70). In the logistic regression analyses, a shorter index duration was identified as a sex-specific predictor for ECT outcome in women (X2(1) = 7.05, p = 0.01). The corresponding predictive margins did show overlapping confidence intervals for men and women. CONCLUSION: The evidence provided by our study suggests that ECT as a biological treatment for MDD is equally effective in women and men. A shorter duration of index episode was an additional sex- specific predictor for remission in women. Future research should establish whether the confidence intervals for the corresponding predictive margins are overlapping, as we find, or not.
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Trastorno Depresivo Mayor , Terapia Electroconvulsiva , Trastornos Psicóticos , Humanos , Femenino , Masculino , Persona de Mediana Edad , Trastorno Depresivo Mayor/tratamiento farmacológico , Escalas de Valoración Psiquiátrica , Resultado del TratamientoRESUMEN
UVB radiation is biologically active; in plants, it can induce a range of molecular, biochemical, morphological and developmental responses. Although much progress has been made in elucidating UVB perception and signalling pathways under controlled laboratory conditions, understanding of the adaptive, ecological role of UVB responses is still very limited. In this study, we looked at the functional role of UVR8 under outdoor light conditions, by studying growth, photosynthetic competence and accumulation of UV absorbing pigments in a mutant lacking functional UVR8 protein. It was found that the influence of UVB on morphology is restricted to summer and is independent of UVR8. In contrast, UVB had an effect on the content of UV-absorbing pigments and the maximal efficiency of photosystem II of photosynthesis in the uvr8-1 mutant throughout the year. It is concluded that the UVR8 photoreceptor plays a role throughout the year, in the temperate climate zone, even when UVB levels are relatively low.
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Absorción de Radiación , Proteínas de Arabidopsis/metabolismo , Arabidopsis/anatomía & histología , Arabidopsis/efectos de la radiación , Proteínas Cromosómicas no Histona/metabolismo , Fotorreceptores de Plantas/metabolismo , Pigmentos Biológicos/metabolismo , Rayos Ultravioleta , Biomasa , Mutación/genética , Fenoles/metabolismo , Complejo de Proteína del Fotosistema II/metabolismo , Desarrollo de la Planta/efectos de la radiación , Hojas de la Planta/metabolismo , Hojas de la Planta/efectos de la radiación , Análisis de Regresión , Estaciones del AñoRESUMEN
Tuberous sclerosis complex (TSC) is an inherited neurocutaneous disorder. Diagnosis of early onset TSC in newborn infants is usually made by cardiac ultrasound because of circulatory problems due to cardiac rhabdomyoma. Early appearance of cortical tubers on cerebral ultrasound in newborn infants is very rare. Mostly TSC is diagnosed on MRI and not by cerebral ultrasound. Subependymal nodules are the usual presenting sign of TSC on cerebral ultrasound in neonates, which are often misdiagnosed as subependymal hemorrhage, calcifications or ischemic lesions after intrauterine germinal matrix hemorrhage. In this case report, multiple cortical and subcortical tubers are demonstrated in an extremely preterm infant, which were not observed on antenatal ultrasound. Together with cardial rhabdomyoma and the identification of the TSC2 pathogenic mutation in DNA from normal tissue the diagnosis of TSC has been confirmed. To our knowledge this is the first case report of early appearance of disseminated cortical tubers on cerebral ultrasound postnatal in an extremely preterm infant with TSC.
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Corteza Cerebral/diagnóstico por imagen , Recien Nacido Extremadamente Prematuro , Rabdomioma/diagnóstico por imagen , Esclerosis Tuberosa/diagnóstico por imagen , Proteínas Supresoras de Tumor/metabolismo , Ultrasonografía , Corteza Cerebral/fisiopatología , Resultado Fatal , Humanos , Recién Nacido , Masculino , Rabdomioma/fisiopatología , Esclerosis Tuberosa/complicaciones , Esclerosis Tuberosa/fisiopatología , Proteína 2 del Complejo de la Esclerosis TuberosaRESUMEN
Previously conducted trials comparing the gait pattern of individuals with a transfemoral amputation using a user-adaptive and a non-microprocessor-controlled prosthetic knee (NMPK) found mixed and conflicting results. Few trials, however, have compared user-adaptive to non-adaptive prosthetic knees across different walking speeds. Because of the ability of variable damping, the effect of user-adaptive knees might be more pronounced at lower or higher walking speeds. Our aim was to compare the Rheo Knee II (a microprocessor-controlled prosthetic knee) with NMPKs across varying walking speeds. In addition, we studied compensatory mechanisms associated with non-optimal prosthetic knee kinematics, such as intact ankle vaulting and vertical acceleration of the pelvis. Nine persons with a transfemoral amputation or knee disarticulation were included and measured with their own NMPK and with the Rheo Knee II. Measurements were performed at three walking speeds: preferred walking speed, 70% preferred walking speed and 115% preferred walking speed. No differences on peak prosthetic knee flexion during swing were found between prosthetic knee conditions. In addition, prosthetic knee flexion increased significantly with walking speed for both prosthetic knee conditions. At 70% preferred walking speed we found that vaulting of the intact ankle was significantly decreased while walking with the Rheo Knee II compared to the NMPK condition (P=0.028). We did not find differences in peak vertical acceleration of the pelvis during initial and mid-swing of the prosthetic leg. In conclusion, comparison of walking with the Rheo Knee II to walking with a NMPK across different walking speeds showed limited differences in gait parameters.
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Marcha , Prótesis de la Rodilla , Velocidad al Caminar , Caminata , Adulto , Anciano , Fenómenos Biomecánicos , Estudios Cruzados , Femenino , Humanos , Masculino , Persona de Mediana Edad , Diseño de Prótesis , Resultado del Tratamiento , Adulto JovenRESUMEN
Patients with schizophrenia are eight times more likely than healthy individuals to become infected with the human immunodeficiency virus (hiv). Although in vitro studies provide some data on the interaction between antipsychotics and retroviral agents, there is a lack of in vitro data on this subject. We describe the case of a 35-year-old patient who suffered from schizophrenia, polydrug abuse and an hiv infection and who also had treatment-resistant psychosis. An interaction between the antiretroviral drug ritonavir and the antipsychotic olanzapine turned out to be the cause of the treatment resistance. As far as we know, this is the first report of such a clinically relevant interaction. We present a review of the current literature on this type of interaction.
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Benzodiazepinas/efectos adversos , Infecciones por VIH/tratamiento farmacológico , Psicosis Inducidas por Sustancias/diagnóstico , Ritonavir/efectos adversos , Esquizofrenia/tratamiento farmacológico , Adulto , Antirretrovirales/efectos adversos , Antirretrovirales/uso terapéutico , Antipsicóticos/efectos adversos , Antipsicóticos/uso terapéutico , Benzodiazepinas/uso terapéutico , Interacciones Farmacológicas , Humanos , Masculino , Olanzapina , Psicosis Inducidas por Sustancias/epidemiología , Ritonavir/uso terapéuticoRESUMEN
In this study we determined if detection of the onset of gait initiation in transfemoral amputees can be useful for voluntary control of upper leg prostheses. From six transfemoral amputees inertial sensor data and EMG were measured at the prosthetic leg during gait initiation. First, initial movement was detected from the inertial sensor data. Subsequently it was determined whether EMG could predict initial movement before detection based on the inertial sensors with comparable consistency as the inertial sensors. From the inertial sensors the initial movement can be determined. If the prosthetic leg leads, the upper leg accelerometer data was able to detect initial movement best. If the intact leg leads the upper leg gyroscope data performed best. Inertial sensors at the upper leg in general showed detections at the same time or earlier than those at the lower leg. EMG can predict initial movement up to a 138 ms in advance, when the prosthetic leg leads. One subject showed consistent EMG onset up to 248 ms before initial movement in the intact leg leading condition. A new method to detect initial movement from inertial sensors was presented and can be useful for additional prosthetic control. EMG measured at the prosthetic leg can be used for prediction of gait initiation when the prosthetic leg is leading, but for the intact leg leading condition this will not be of additional value.
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Amputación Quirúrgica , Miembros Artificiales , Marcha/fisiología , Monitoreo Fisiológico/instrumentación , Adulto , Fenómenos Biomecánicos , Electromiografía , Femenino , Humanos , Pierna , Masculino , Persona de Mediana EdadRESUMEN
Observation of a potentiometric sensor's response behaviour after injection in flow injection analysis at different concentrations allowed studying "on" and "off" kinetics of the analyte's adsorption/diffusion behaviour. The alkaloid metergoline was mostly used as an example. k(on) and k(off) rate constant values were measured, and the association constant K(ass), and ΔG values of the analyte-surface interaction were calculated with an adsorption-based model which proved to be fully applicable. k(on) increased by decreasing the sensor dimensions, while koff was unaffected by miniaturization. Increasing acetonitrile concentrations in the running buffer increased k(off), while k(on) was unaffected. The experimentally determined ΔG values of the analyte-surface interaction showed a linear relation to the response of the sensor, in mV. This knowledge was applied to optimize the potentiometric detection of plant alkaloids in (U)HPLC. Sub-micromolar detection limits were obtained with the potentiometric detector/(U)HPLC combination. This is the first time that the response rates and the response itself can be modelled accurately for coated wire potentiometric sensors, and it is the first application of a potentiometric detector in UPLC.
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Cromatografía Líquida de Alta Presión , Potenciometría , Acetonitrilos/análisis , Adsorción , Alcaloides/análisis , Cocaína/análisis , Diosgenina/análisis , Cinética , Metergolina/análisis , Modelos Químicos , Papaverina/análisis , Plantas/química , Potenciometría/instrumentaciónRESUMEN
OBJECTIVES: To investigate which anthropometric adiposity measure has the strongest association with cardiovascular disease (CVD) risk factors in Caucasian men and women without a history of CVD. DESIGN: Systematic review and meta-analysis. METHODS: We searched databases for studies reporting correlations between anthropometric adiposity measures and CVD risk factors in Caucasian subjects without a history of CVD. Body mass index (BMI), waist circumference, waist-to-hip ratio, waist-to-height ratio and body fat percentage were considered the anthropometric adiposity measures. Primary CVD risk factors were: systolic blood pressure, diastolic blood pressure, high density lipoprotein (HDL) cholesterol, triglycerides and fasting glucose. Two independent reviewers performed abstract, full text and data selection. RESULTS: Twenty articles were included describing 21,618 males and 24,139 females. Waist circumference had the strongest correlation with all CVD risk factors for both men and women, except for HDL and LDL in men. When comparing BMI with waist circumference, the latter showed significantly better correlations to CVD risk factors, except for diastolic blood pressure in women and HDL and total cholesterol in men. CONCLUSIONS: We recommend the use of waist circumference in clinical and research studies above other anthropometric adiposity measures, especially compared with BMI, when evaluating CVD risk factors.
RESUMEN
The regulation of photosynthetic acclimation to canopy density was investigated in tobacco canopies and in tobacco and Arabidopsis plants with part of their foliage experimentally shaded. Both species acclimated to canopy light gradients and partial shading by allocating photosynthetic capacity to leaves in high light and adjusting chloroplast organization to the local light conditions. An investigation was carried out to determine whether signalling mediated by photoreceptors, sugars, cytokinin, and nitrate is involved in and necessary for proper photosynthetic acclimation. No evidence was found for a role for sugars, or for nitrate. The distribution of cytokinins in tobacco stands of contrasting density could be explained in part by irradiance-dependent delivery of cytokinins through the transpiration stream. Functional studies using a comprehensive selection of Arabidopsis mutants and transgenics showed that normal wild-type responses to partial shading were retained when signalling mediated by photoreceptors or cytokinins was disrupted. This indicates that these pathways probably operate in a redundant manner. However, the reduction of the chlorophyll a/b ratio in response to local shade was completely absent in the Arabidopsis Ws-2 accession mutated in PHYTOCHROME D and in the triple phyAphyCphyD mutant. Moreover, cytokinin receptor mutants also showed a reduced response, suggesting a previously unrecognized function of phyD and cytokinins.
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Aclimatación , Citocininas/metabolismo , Fotorreceptores de Plantas/metabolismo , Fotosíntesis , Hojas de la Planta/fisiología , Arabidopsis/genética , Cloroplastos/metabolismo , Transporte de Electrón , Mutación/genética , Transpiración de Plantas , Plantas Modificadas Genéticamente , Nicotiana/fisiologíaRESUMEN
The practice of coercive measures in psychiatry is controversial. Although some have suggested that it may be acceptable if patients are a danger to others or to themselves, others committed themselves to eliminate it. Ethical, legal and clinical considerations become more complex when the mental incapacity is temporary and when the coercive measures serve to restore autonomy. We discuss these issues, addressing the conflict between autonomy and beneficence/non-maleficence, human dignity, the experiences of patients and the effects of coercive measures. We argue that an appeal to respect autonomy and/or human dignity cannot be a sufficient reason to reject coercive measures. All together, these ethical aspects can be used both to support and to reject a non-seclusion approach. The total lack of controlled trials about the beneficial effects of coercive measures in different populations however, argues against the use of coercive measures.
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Servicios de Salud Mental/ética , Derechos del Paciente/ética , Psiquiatría/ética , Restricción Física/ética , Coerción , Internamiento Obligatorio del Enfermo Mental/legislación & jurisprudencia , Conducta Peligrosa , Ética Médica , Humanos , Trastornos Mentales/terapia , Autonomía Personal , Psiquiatría/métodos , Restricción Física/legislación & jurisprudenciaRESUMEN
Mass spectrometric analysis revealed the presence of auxin, mainly in conjugated form, in secretions of Heterodera schachtii and Meloidogyne incognita, with or without treatment with DMT or resorcinol. M. incognita showed the highest production rates, though treatment of M. incognita with resorcinol had a negative effect on auxin production. Analysis of auxin precursor molecules in lysates of H. schachtii, M. incognita and Caenorhabditis elegans suggested that auxin is most probably a degradation product of tryptophan and that auxin may be synthesized via several intermediates, including indole-3-acetamide which is an intermediate of a pathway so far only characterized in bacteria. Furthermore, high levels of anthranilate, a degradation product of tryptophan in animals, but possibly also a precursor for auxin were detected.
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Productos Agrícolas/parasitología , Ácidos Indolacéticos/análisis , Reguladores del Crecimiento de las Plantas/análisis , Tylenchoidea/metabolismo , Animales , Caenorhabditis elegans/metabolismo , Interacciones Huésped-Parásitos , Ácidos Indolacéticos/metabolismo , Espectrometría de Masas , Reguladores del Crecimiento de las Plantas/biosíntesis , Reguladores del Crecimiento de las Plantas/metabolismoRESUMEN
Expression of the Azospirillum brasilense ipdC gene, encoding an indole-3-pyruvate decarboxylase, a key enzyme in the production of indole-3-acetic acid (IAA) in this bacterium, is upregulated by IAA. Here, we demonstrate that the ipdC gene is the promoter proximal gene in a bicistronic operon. Database searches revealed that the second gene of this operon, named iaaC, is well conserved evolutionarily and that the encoded protein is homologous to the Escherichia coli protein SCRP-27A, the zebrafish protein ES1, and the human protein KNP-I/GT335 (HES1), all of unknown function and belonging to the DJ-1/PfpI superfamily. In addition to this operon structure, iaaC is also transcribed monocistronically. Mutation analysis of the latter gene indicated that the encoded protein is involved in controlling IAA biosynthesis but not ipdC expression. Besides being upregulated by IAA, expression of the ipdC-iaaC operon is pH dependent and maximal at acidic pH. The ipdC promoter was studied using a combination of deletion analyses and site-directed mutagenesis. A dyadic sequence (ATTGTTTC(GAAT)GAAACAAT), centered at -48 was demonstrated to be responsible for the IAA inducibility. This bacterial auxin-responsive element does not control the pH-dependent expression of ipdC-iaaC.
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Azospirillum brasilense/genética , Carboxiliasas/genética , Expresión Génica , Ácidos Indolacéticos/metabolismo , Transcripción Genética , Región de Flanqueo 5' , Secuencia de Aminoácidos , Secuencia de Bases , Concentración de Iones de Hidrógeno , Cinética , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Mapeo Físico de Cromosoma , Alineación de Secuencia , Factores de TiempoRESUMEN
In Pssu-ipt-transformed tobacco, apical dominance was released by defoliation of the upper nodes, while the apex remained intact. After defoliation, the concentration of cytokinins (CKs) increased whereas IAA remained constant, evoking an increase in the CK/IAA ratio in the buds. Moreover, defoliation resulted in a tremendous increase in the concentrations of aromatic amines (AAs): tyramine (TYR), phenethylamine (PEA) and an as yet unidentified compound. Although the total aliphatic monoamine and polyamine (PA) concentration remained constant, putrescine (PUT) and spermidine (SPD) concentrations in the axillary buds decreased, whereas the concentration of spermine (SPM) increased. Similar changes in PAs and AAs could be observed in the buds of untransformed SR1 plants after decapitation, whereas defoliation without removal of the apex had no effect. This is the first report on the possible involvement of PAs and AAs in apical dominance.
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Nicotiana/crecimiento & desarrollo , Transformación Genética , Cromatografía Líquida de Alta Presión , Nicotiana/genéticaRESUMEN
Endogenous extractable factors associated with auxin action in plant tissues were investigated, especially their effects on elongation of 1-mm coleoptile segments of maize (Zea mays L.), in the presence of saturating 10 microM indole-3-acetic acid (IAA). The relative growth response, to auxin alone, was much smaller in segments shorter than 2-3 mm compared to 10-mm segments. Fusicoccin-induced elongation, however, was less affected by shortening the segments. A reduced auxin response may result from the depletion through cut surfaces of a substance required for IAA-mediated growth. Sucrose, phenolics like flavonoids, and vitamins were ruled out as the causal factors. A partially purified methanol extract of maize coleoptiles supported longterm, auxin-controlled elongation. The active material was also found among substances bleeding from scrubbed maize coleoptiles. The active factor from maize was further purified by HPLC and characterised by the UV spectrum and its pH shift. This factor was identified as 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) by mass spectroscopy. Activity tests confirmed that pure DIMBOA from other sources sustained auxin-induced elongation of short maize coleoptile segments. However, DIMBOA only partially restored the activity lost from short segments. This indicates that an additional factor, other than DIMBOA, is required. Extracts from Avena or Cucurbita did not contain the factor DIMBOA; it was active on maize elongation, but not on Avena coleoptiles or Cucurbita hypocotyls. This narrow specificity and the lack of DIMBOA action in short-term tests with maize indicate that DIMBOA is not the general auxin cofactor but may specifically "spare" the co-auxin in maize.
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Cotiledón/crecimiento & desarrollo , Ácidos Indolacéticos/farmacología , Oxazinas/farmacología , Reguladores del Crecimiento de las Plantas/farmacología , Zea mays/crecimiento & desarrollo , Benzoxazinas , División Celular , Cotiledón/efectos de los fármacos , Glicósidos/farmacología , Oxazinas/química , Oxazinas/aislamiento & purificación , Zea mays/químicaRESUMEN
We have studied the mechanism of UV protection in two duckweed species (Lemnaceae) by exploiting the UV sensitivity of photosystem II as an in situ sensor for radiation stress. A UV-tolerant Spirodela punctata G.F.W. Meyer ecotype had significantly higher indole-3-acetic acid (IAA) levels than a UV-sensitive ecotype. Parallel work on Lemna gibba mutants suggested that UV tolerance is linked to IAA degradation rather than to levels of free or conjugated IAA. This linkage is consistent with a role for class III phenolic peroxidases, which have been implicated both in the degradation of IAA and the cross-linking of various UV-absorbing phenolics. Biochemical analysis revealed increased activity of a specific peroxidase isozyme in both UV-tolerant duckweed lines. The hypothesis that peroxidases play a role in UV protection was tested in a direct manner using genetically modified tobacco (Nicotiana sylvestris). It was found that increased activity of the anionic peroxidase correlated with increased tolerance to UV radiation as well as decreased levels of free auxin. We conclude that phenol-oxidizing peroxidases concurrently contribute to UV protection as well as the control of leaf and plant architecture.
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Magnoliopsida/efectos de la radiación , Peroxidasas/metabolismo , Rayos Ultravioleta , Ácidos Indolacéticos/metabolismo , Fenoles/metabolismo , Fotosíntesis , Plantas Tóxicas , Tolerancia a Radiación , Nicotiana/efectos de la radiaciónRESUMEN
Survival of rice (Oryza sativa) upon an extreme rise of the water level depends on rapid stem elongation, which is mediated by ethylene. A genomic clone (OS-ACS5) encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase, which catalyzes a regulatory step in ethylene biosynthesis, has been isolated from cv IR36, a lowland rice variety. Expression was induced upon short- and long-term submergence in cv IR36 and in cv Plai Ngam, a Thai deepwater rice variety. Under hypoxic conditions, abscisic acid and gibberellin had a reciprocal opposite effect on the activity of OS-ACS5. Gibberellin up-regulated and abscisic acid down-regulated OS-ACS5 mRNA accumulation. Growth experiments indicated that lowland rice responded to submergence with a burst of growth early on, but lacked the ability to sustain elongation growth. Sustained growth, characteristic for deepwater rice, was correlated with a prolonged induction of OS-ACS5. In addition, a more pronounced capacity to convert ACC to ethylene, a limited ACC conjugation, and a high level of endogenous gibberellin(20) were characteristic for the deepwater variety. An elevated level of OS-ACS5 messenger was found in cv IR36 plants treated with exogenous ACC. This observation was concomitant with an increase in the capacity of converting ACC to ethylene and in elongation growth, and resulted in prolonged survival. In conclusion, OS-ACS5 is involved in the rapid elongation growth of deepwater rice by contributing to the initial and long-term increase in ethylene levels. Our data also suggest that ACC limits survival of submerged lowland rice seedlings.
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Oryza/crecimiento & desarrollo , Oryza/genética , Agricultura/métodos , Secuencia de Bases , Clorofila/metabolismo , Cicloheximida/farmacología , Datos de Secuencia Molecular , Oryza/efectos de los fármacos , Reacción en Cadena de la Polimerasa , Regiones Promotoras Genéticas , ARN Mensajero/química , ARN Mensajero/genética , Alineación de Secuencia , Homología de Secuencia de Ácido Nucleico , AguaRESUMEN
Plant growth, development, and morphology can be affected by several environmental stimuli and by specific interactions with phytopathogens. In many cases, plants respond to pathogenic stimuli by adapting their hormone levels. Here, the interaction between the phytopathogen Rhodococcus fascians and one of its host plants, tobacco, was analyzed phenotypically and molecularly. To elucidate the basis of the cell division modulation and shoot primordia initiation caused by R. fascians, tobacco plants were infected at leaf axils and shoot apices. Adventitious meristems that gave rise to multiple-shoot primordia (leafy galls) were formed. The use of a transgenic line carrying the mitotic CycB1 promoter fused to the reporter gene coding for beta-glucuronidase from Escherichia coli (uidA), revealed that stem cortical cells were stimulated to divide in an initial phase of the leafy gall ontogenesis. Local cytokinin and auxin levels throughout the infection process as well as modulation of expression of the cell cycle regulator gene Nicta;CycD3;2 are discussed.
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División Celular , Nicotiana/microbiología , Plantas Tóxicas , Rhodococcus/fisiología , Ciclina D3 , Ciclinas/genética , Citocininas/fisiología , Ácidos Indolacéticos/metabolismo , Datos de Secuencia Molecular , ARN Mensajero/genética , ARN Mensajero/metabolismoRESUMEN
The open reading frame 8 (ORF8) is located on the TL-DNA of the phytopathogenic soil bacterium Agrobacterium rhizogenes strain A4. The predicted ORF8 protein has a particular structure and is possibly a natural fusion protein. The N-terminal domain shows homology to the A. rhizogenes rolB protein and may modulate the auxin responsiveness of host cells. The C terminus has up to 38% homology to tryptophan 2-monooxygenases (t2m). We show that ORF8 overexpressing plants contain a fivefold higher concentration of indole-3-acetamide (IAM) than untransformed plants. Protein extracts from seedlings and Escherichia coli overexpressing ORF8 show significantly higher turnover rates of tryptophan to IAM than negative controls. We conclude that the ORF8 gene product has tryptophan 2-monooxygenase activity.