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1.
Eur Radiol ; 33(11): 7807-7817, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37212845

RESUMEN

OBJECTIVES: Non-contrast computed tomography (NCCT) markers are robust predictors of parenchymal hematoma expansion in intracerebral hemorrhage (ICH). We investigated whether NCCT features can also identify ICH patients at risk of intraventricular hemorrhage (IVH) growth. METHODS: Patients with acute spontaneous ICH admitted at four tertiary centers in Germany and Italy were retrospectively included from January 2017 to June 2020. NCCT markers were rated by two investigators for heterogeneous density, hypodensity, black hole sign, swirl sign, blend sign, fluid level, island sign, satellite sign, and irregular shape. ICH and IVH volumes were semi-manually segmented. IVH growth was defined as IVH expansion > 1 mL (eIVH) or any delayed IVH (dIVH) on follow-up imaging. Predictors of eIVH and dIVH were explored with multivariable logistic regression. Hypothesized moderators and mediators were independently assessed in PROCESS macro models. RESULTS: A total of 731 patients were included, of whom 185 (25.31%) suffered from IVH growth, 130 (17.78%) had eIVH, and 55 (7.52%) had dIVH. Irregular shape was significantly associated with IVH growth (OR 1.68; 95%CI [1.16-2.44]; p = 0.006). In the subgroup analysis stratified by the IVH growth type, hypodensities were significantly associated with eIVH (OR 2.06; 95%CI [1.48-2.64]; p = 0.015), whereas irregular shape (OR 2.72; 95%CI [1.91-3.53]; p = 0.016) in dIVH. The association between NCCT markers and IVH growth was not mediated by parenchymal hematoma expansion. CONCLUSIONS: NCCT features identified ICH patients at a high risk of IVH growth. Our findings suggest the possibility to stratify the risk of IVH growth with baseline NCCT and might inform ongoing and future studies. CLINICAL RELEVANCE STATEMENT: Non-contrast CT features identified ICH patients at a high risk of intraventricular hemorrhage growth with subtype-specific differences. Our findings may assist in the risk stratification of intraventricular hemorrhage growth with baseline CT and might inform ongoing and future clinical studies. KEY POINTS: • NCCT features identified ICH patients at a high risk of IVH growth with subtype-specific differences. • The effect of NCCT features was not moderated by time and location or indirectly mediated by hematoma expansion. • Our findings may assist in the risk stratification of IVH growth with baseline NCCT and might inform ongoing and future studies.


Asunto(s)
Hemorragia Cerebral , Tomografía Computarizada por Rayos X , Humanos , Estudios Retrospectivos , Tomografía Computarizada por Rayos X/métodos , Hemorragia Cerebral/diagnóstico por imagen , Hematoma/diagnóstico por imagen , Alemania/epidemiología
2.
EMBO Rep ; 20(7): e48541, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31267713

RESUMEN

Experiments in space and on free-fall platforms have yielded important insights into plant's reaction to low gravity with potential applications for space research and exploration.


Asunto(s)
Fenómenos Fisiológicos de las Plantas , Ingravidez , Producción de Cultivos/métodos , Exobiología/métodos , Simulación del Espacio/métodos
3.
Stroke ; 50(1): 83-87, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30580701

RESUMEN

Background and Purpose- Arterial ischemic stroke (AIS) in childhood is a severe disease with potentially lifelong restrictions. Apart from cardiac or prothrombotic embolism, arteriopathy has been identified as a major cause and significant target of secondary stroke prevention. The Childhood Arterial Ischemic Stroke Standardized Classification and Diagnostic Evaluation (CASCADE) criteria facilitate a structured tool for categorizing and reporting childhood strokes according to the underlying cause. Our study aims to identify the prognostic value of CASCADE classification on admission for further course of arteriopathy and risk of stroke recurrence. Moreover, we give recommendations for follow-up imaging based on different CASCADE subgroups. Methods- Between 2004 and 2017, we identified 86 children with an acute arterial ischemic stroke classified in the 7-basic and 19-expanded subgroups of the acute CASCADE criteria. All included children were diagnosed and followed-up by magnetic resonance imaging. All arteriopathic strokes (basic subgroups 1-4 of acute CASCADE criteria) were further categorized into the chronic CASCADE criteria, including progressive, stable, reversible, and indeterminate course. Outcomes were defined as stroke recurrence and course of arteriopathy according to chronic CASCADE criteria. Associations between acute CASCADE criteria classification and stroke recurrence were assessed by Fisher exact test and between acute CASCADE criteria and chronic CASCADE criteria by Fisher exact test and Mann-Whitney U test. Results- A total of 86 children were included; of these, 57 presented with arteriopathic stroke (CASCADE 1-4) and 29 as nonarteriopathic. Unilateral cerebral arteriopathy (CASCADE 2; P=0.036) and bilateral cerebral arteriopathy (CASCADE 3; P=0.016) significantly correlated with stroke recurrence, and progressive arteriopathy significantly correlated with unilateral focal cerebral arteriopathy (P<0.001). Time points of progress of arteriopathy differed; whereas patients with unilateral focal cerebral arteriopathy presented with early median progress after 11 days, patients with bilateral cerebral arteriopathy had a significantly later median progress after 124 days (P=0.005). Conclusions- Initial CASCADE classification is associated with risk of recurrent strokes and progress of arteriopathy. Moreover, time points of arteriopathic progress vary according to the underlying cause.

5.
Plant Physiol ; 169(2): 1168-78, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26243620

RESUMEN

Elevated carbon dioxide (CO2) in leaves closes stomatal apertures. Research has shown key functions of the ß-carbonic anhydrases (ßCA1 and ßCA4) in rapid CO2-induced stomatal movements by catalytic transmission of the CO2 signal in guard cells. However, the underlying mechanisms remain unclear, because initial studies indicate that these Arabidopsis (Arabidopsis thaliana) ßCAs are targeted to distinct intracellular compartments upon expression in tobacco (Nicotiana benthamiana) cells. Which cellular location of these enzymes plays a key role in native guard cells in CO2-regulated stomatal movements remains unknown. Here, we express fluorescently tagged CAs in guard cells of ca1ca4 double-mutant plants and show that the specific locations of ßCA4 at the plasma membrane and ßCA1 in native guard cell chloroplasts each can mediate rapid CO2 control of stomatal movements. Localization and complementation analyses using a mammalian αCAII-yellow fluorescent protein in guard cells further show that cytoplasmic localization is also sufficient to restore CO2 regulation of stomatal conductance. Mathematical modeling of cellular CO2 catalysis suggests that the dynamics of the intracellular HCO3 (-) concentration change in guard cells can be driven by plasma membrane and cytoplasmic localizations of CAs but not as clearly by chloroplast targeting. Moreover, modeling supports the notion that the intracellular HCO3 (-) concentration dynamics in guard cells are a key mechanism in mediating CO2-regulated stomatal movements but that an additional chloroplast role of CAs exists that has yet to be identified.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Dióxido de Carbono/metabolismo , Anhidrasas Carbónicas/metabolismo , Estomas de Plantas/fisiología , Secuencia de Aminoácidos , Arabidopsis/citología , Proteínas de Arabidopsis/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Anhidrasas Carbónicas/genética , Membrana Celular/metabolismo , Cloroplastos/genética , Cloroplastos/metabolismo , Citosol/metabolismo , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Humanos , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , Modelos Biológicos , Datos de Secuencia Molecular , Células Vegetales/metabolismo , Estomas de Plantas/metabolismo , Plantas Modificadas Genéticamente , Nicotiana/genética , Nicotiana/metabolismo
6.
J Neurol ; 271(8): 5003-5011, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38775933

RESUMEN

BACKGROUND: Hematoma volume is a major pathophysiological hallmark of acute intracerebral hemorrhage (ICH). We investigated how the variance in functional outcome induced by the ICH volume is explained by neurological deficits at admission using a mediation model. METHODS: Patients with acute ICH treated in three tertiary stroke centers between January 2010 and April 2019 were retrospectively analyzed. Mediation analysis was performed to investigate the effect of ICH volume (0.8 ml (5% quantile) versus 130.6 ml (95% quantile)) on the risk of unfavorable functional outcome at discharge defined as modified Rankin Score (mRS) ≥ 3 with mediation through National Institutes of Health Stroke Scale (NIHSS) at admission. Multivariable regression was conducted to identify factors related to neurological improvement and deterioration. RESULTS: Three hundred thirty-eight patients were analyzed. One hundred twenty-one patients (36%) achieved mRS ≤ 3 at discharge. Mediation analysis showed that NIHSS on admission explained 30% [13%; 58%] of the ICH volume-induced variance in functional outcome at smaller ICH volume levels, and 14% [4%; 46%] at larger ICH volume levels. Higher ICH volume at admission and brainstem or intraventricular location of ICH were associated with neurological deterioration, while younger age, normotension, lower ICH volumes, and lobar location of ICH were predictors for neurological improvement. CONCLUSION: NIHSS at admission reflects 14% of the functional outcome at discharge for larger hematoma volumes and 30% for smaller hematoma volumes. These results underscore the importance of effects not reflected in NIHSS admission for the outcome of ICH patients such as secondary brain injury and early rehabilitation.


Asunto(s)
Hemorragia Cerebral , Humanos , Masculino , Femenino , Anciano , Persona de Mediana Edad , Hemorragia Cerebral/fisiopatología , Hemorragia Cerebral/diagnóstico por imagen , Estudios Retrospectivos , Anciano de 80 o más Años , Recuperación de la Función/fisiología , Evaluación de Resultado en la Atención de Salud , Admisión del Paciente , Índice de Severidad de la Enfermedad
7.
Mol Plant Microbe Interact ; 26(6): 626-32, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23441577

RESUMEN

Guard cells regulate plant gas exchange and transpiration by modulation of stomatal aperture upon integrating external cues like photosynthetic effective illumination, CO2 levels and water availability and internal signals like abscisic acid (ABA). Being pores, stomata constitute a natural entry site for potentially harmful microbes. To prevent microbial invasion, stomata close upon perception of microbe-associated molecular patterns (MAMPs), and this represents an important layer of active immunity at the preinvasive level. The signaling pathways leading to stomatal closure triggered by biotic and abiotic stresses employ several common components, such as reactive oxygen species, calcium, kinases, and hormones, suggesting considerable intersection between MAMP- and ABA-induced stomatal closures, which we will discuss in this review.


Asunto(s)
Enfermedades de las Plantas/inmunología , Estomas de Plantas/inmunología , Plantas/inmunología , Transducción de Señal/inmunología , Ácido Abscísico/metabolismo , Calcio/metabolismo , Dióxido de Carbono/metabolismo , Óxido Nítrico/metabolismo , Fosfotransferasas/metabolismo , Enfermedades de las Plantas/microbiología , Fenómenos Fisiológicos de las Plantas , Proteínas de Plantas/metabolismo , Estomas de Plantas/fisiología , Plantas/enzimología , Plantas/microbiología , Especies Reactivas de Oxígeno/metabolismo , Estrés Fisiológico
8.
Front Mol Biosci ; 10: 1258374, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37860582

RESUMEN

Background: Primary ciliary dyskinesia (PCD; MIM 242650) is a rare genetic disorder characterized by malfunction of the motile cilia resulting in reduced mucociliary clearance of the airways. Together with recurring infections of the lower respiratory tract, chronic rhinosinusitis (CRS) is a hallmark symptom of PCD. Data on genotype-phenotype correlations in the upper airways are scarce. Materials and methods: We investigated the prevalence, radiologic severity, and impact on health-related quality of life (HrQoL) of CRS in 58 individuals with genetically confirmed PCD. Subgroup analysis was performed according to the predicted ultrastructural phenotype based on genetic findings. Results: Among 58 individuals harboring pathogenic variants in 22 distinct genes associated with PCD, all were diagnosed with CRS, and 47% underwent sinus surgery. A total of 36 individuals answered a German-adapted version of the 20-item Sinonasal Outcome Test (SNOT-20-GAV) with a mean score of 35.8 ± 17, indicating a remarkably reduced HrQoL. Paranasal sinus imaging of 36 individuals showed moderate-to-severe opacification with an elevated Lund-Mackay Score (LMS) of 10.2 ± 4.4. Bilateral agenesis of frontal sinus (19%) and sphenoid sinus (9.5%) was a frequent finding in individuals aged 16 years or older. Subgroup analysis for predicted ultrastructural phenotypes did not identify differences in HrQoL, extent of sinus opacification, or frequency of aplastic paranasal sinuses. Conclusion: PCD is strongly associated with CRS. The high burden of disease is indicated by decreased HrQoL. Therefore, the upper airways of PCD individuals should be evaluated and managed by ear-nose-throat (ENT) specialists. Genetically determined PCD groups with predicted abnormal versus (near) normal ultrastructure did not differ in disease severity. Further studies are needed to gain evidence-based knowledge of the phenotype and management of upper airway manifestations in PCD. In addition, individuals with agenesis of the frontal and sphenoid paranasal sinuses and chronic respiratory symptoms should be considered for a diagnostic evaluation of PCD.

9.
Cells ; 12(7)2023 03 29.
Artículo en Inglés | MEDLINE | ID: mdl-37048115

RESUMEN

Microgravity (µg) has a massive impact on the health of space explorers. Microgravity changes the proliferation, differentiation, and growth of cells. As crewed spaceflights into deep space are being planned along with the commercialization of space travelling, researchers have focused on gene regulation in cells and organisms exposed to real (r-) and simulated (s-) µg. In particular, cancer and metastasis research benefits from the findings obtained under µg conditions. Gene regulation is a key factor in a cell or an organism's ability to sustain life and respond to environmental changes. It is a universal process to control the amount, location, and timing in which genes are expressed. In this review, we provide an overview of µg-induced changes in the numerous mechanisms involved in gene regulation, including regulatory proteins, microRNAs, and the chemical modification of DNA. In particular, we discuss the current knowledge about the impact of microgravity on gene regulation in different types of bacteria, protists, fungi, animals, humans, and cells with a focus on the brain, eye, endothelium, immune system, cartilage, muscle, bone, and various cancers as well as recent findings in plants. Importantly, the obtained data clearly imply that µg experiments can support translational medicine on Earth.


Asunto(s)
MicroARNs , Vuelo Espacial , Ingravidez , Animales , Humanos , Regulación de la Expresión Génica , Diferenciación Celular , MicroARNs/genética
10.
Plant J ; 67(1): 105-18, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21426425

RESUMEN

Early rapid changes in response to the phytohormone abscisic acid (ABA) have been observed at the transcript level, but little is known how these transcript changes translate to changes in protein abundance under the same conditions. Here we have performed a global quantitative analysis of transcript and protein changes in Arabidopsis suspension cells in response to ABA using microarrays and quantitative proteomics. In summary, 3494 transcripts and 50 proteins were significantly regulated by ABA over a treatment period of 20-24 h. Abscisic acid also caused a rapid and strong increase in production of extracellular reactive oxygen species (ROS) with an average half-rise time of 33 sec. A subset of ABA-regulated transcripts were differentially regulated in the presence of the ROS scavenger dimethylthiourea (DMTU) as compared with ABA alone, suggesting a role for ROS in the regulation of these ABA-induced genes. Transcript changes showed an overall poor correlation to protein changes (r = 0.66). Only a subset of genes was regulated at the transcript and protein level, including known ABA marker genes. We furthermore identified ABA regulation of proteins that function in a branch of glucosinolate catabolism previously not associated with ABA signaling. The discovery of genes that were differentially regulated at the transcript and at the protein level emphasizes the strength of our combined approach. In summary, our dataset not only expands previous studies on gene and protein regulation in response to ABA, but rather uncovers unique aspects of the ABA regulon and gives rise to additional mechanisms regulated by ABA.


Asunto(s)
Ácido Abscísico/farmacología , Arabidopsis/metabolismo , Perfilación de la Expresión Génica/métodos , Reguladores del Crecimiento de las Plantas/farmacología , Proteómica/métodos , Especies Reactivas de Oxígeno/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Técnicas de Cultivo de Célula , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Glucosinolatos/metabolismo , Mutación , Análisis de Secuencia por Matrices de Oligonucleótidos , Proteínas Serina-Treonina Quinasas/metabolismo , ARN Mensajero/genética , ARN de Planta/genética , Estallido Respiratorio , Transducción de Señal/efectos de los fármacos , Tiourea/análogos & derivados , Tiourea/metabolismo
11.
Biomedicines ; 10(1)2022 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-35052817

RESUMEN

Calcium (Ca2+) elevation is an essential secondary messenger in many cellular processes, including disease progression and adaptation to external stimuli, e.g., gravitational load. Therefore, mapping and quantifying Ca2+ signaling with a high spatiotemporal resolution is a key challenge. However, particularly on microgravity platforms, experiment time is limited, allowing only a small number of replicates. Furthermore, experiment hardware is exposed to changes in gravity levels, causing experimental artifacts unless appropriately controlled. We introduce a new experimental setup based on the fluorescent Ca2+ reporter CaMPARI2, onboard LED arrays, and subsequent microscopic analysis on the ground. This setup allows for higher throughput and accuracy due to its retrograde nature. The excellent performance of CaMPARI2 was demonstrated with human chondrocytes during the 75th ESA parabolic flight campaign. CaMPARI2 revealed a strong Ca2+ response triggered by histamine but was not affected by the alternating gravitational load of a parabolic flight.

12.
Tomography ; 8(6): 2893-2901, 2022 12 09.
Artículo en Inglés | MEDLINE | ID: mdl-36548534

RESUMEN

BACKGROUND: Noncontrast Computed Tomography (NCCT) features are promising markers for acute hematoma expansion (HE) in patients with intracerebral hemorrhage (ICH). It remains unclear whether accurate identification of these markers is also reliable in raters with different levels of experience. METHODS: Patients with acute spontaneous ICH admitted at four tertiary centers in Germany and Italy were retrospectively included from January 2017 to June 2020. In total, nine NCCT markers were rated by one radiology resident, one radiology fellow, and one neuroradiology fellow with different levels experience in ICH imaging. Interrater reliabilities of the resident and radiology fellow were evaluated by calculated Cohen's kappa (κ) statistics in reference to the neuroradiology fellow who was referred as the gold standard. Gold-standard ratings were evaluated by calculated interrater κ statistics. Global interrater reliabilities were evaluated by calculated Fleiss kappa statistics across all three readers. A comparison of receiver operating characteristics (ROCs) was used to evaluate differences in the diagnostic accuracy for predicting acute hematoma expansion (HE) among the raters. RESULTS: Substantial-to-almost-perfect interrater concordance was found for the resident with interrater Cohen's kappa from 0.70 (95% CI 0.65-0.81) to 0.96 (95% CI 0.94-0.98). The interrater Cohen's kappa for the radiology fellow was moderate to almost perfect and ranged from 0.58 (95% CI 0.52-0.65) to 94 (95% CI 92-0.97). The intrarater gold-standard Cohen's kappa was almost perfect and ranged from 0.79 (95% CI 0.78-0.90) to 0.98 (95% CI 0.78-0.90). The global interrater Fleiss kappa ranged from 0.62 (95%CI 0.57-0.66) to 0.93 (95%CI 0.89-0.97). The diagnostic accuracy for the prediction of acute hematoma expansion (HE) was different for the island sign and fluid sign, with p-values < 0.05. CONCLUSION: The NCCT markers had a substantial-to-almost-perfect interrater agreement among raters with different levels of experience. Differences in the diagnostic accuracy for the prediction of acute HE were found in two out of nine NCCT markers. The study highlights the promising utility of NCCT markers for acute HE prediction.


Asunto(s)
Hemorragia Cerebral , Tomografía Computarizada por Rayos X , Humanos , Estudios Retrospectivos , Reproducibilidad de los Resultados , Hemorragia Cerebral/diagnóstico por imagen , Hematoma/diagnóstico por imagen , Radiólogos
13.
Transl Stroke Res ; 12(6): 958-967, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-33547592

RESUMEN

We hypothesized that imaging-only-based machine learning algorithms can analyze non-enhanced CT scans of patients with acute intracerebral hemorrhage (ICH). This retrospective multicenter cohort study analyzed 520 non-enhanced CT scans and clinical data of patients with acute spontaneous ICH. Clinical outcome at hospital discharge was dichotomized into good outcome and poor outcome using different modified Rankin Scale (mRS) cut-off values. Predictive performance of a random forest machine learning approach based on filter- and texture-derived high-end image features was evaluated for differentiation of functional outcome at mRS 2, 3, and 4. Prediction of survival (mRS ≤ 5) was compared to results of the ICH Score. All models were tuned, validated, and tested in a nested 5-fold cross-validation approach. Receiver-operating-characteristic area under the curve (ROC AUC) of the machine learning classifier using image features only was 0.80 (95% CI [0.77; 0.82]) for predicting mRS ≤ 2, 0.80 (95% CI [0.78; 0.81]) for mRS ≤ 3, and 0.79 (95% CI [0.77; 0.80]) for mRS ≤ 4. Trained on survival prediction (mRS ≤ 5), the classifier reached an AUC of 0.80 (95% CI [0.78; 0.82]) which was equivalent to results of the ICH Score. If combined, the integrated model showed a significantly higher AUC of 0.84 (95% CI [0.83; 0.86], P value <0.05). Accordingly, sensitivities were significantly higher at Youden Index maximum cut-offs (77% vs. 74% sensitivity at 76% specificity, P value <0.05). Machine learning-based evaluation of quantitative high-end image features provided the same discriminatory power in predicting functional outcome as multidimensional clinical scoring systems. The integration of conventional scores and image features had synergistic effects with a statistically significant increase in AUC.


Asunto(s)
Hemorragia Cerebral , Aprendizaje Automático , Hemorragia Cerebral/diagnóstico por imagen , Estudios de Cohortes , Humanos , Pronóstico , Estudios Retrospectivos
14.
Genes (Basel) ; 11(6)2020 06 12.
Artículo en Inglés | MEDLINE | ID: mdl-32545654

RESUMEN

Temperature elevations constitute a major threat to plant performance. In recent years, much was learned about the general molecular mode of heat stress reaction of plants. The current research focuses on the integration of the knowledge into more global networks, including the reactions of cellular compartments. For instance, chloroplast function is central for plant growth and survival, and the performance of chloroplasts is tightly linked to the general status of the cell and vice versa. We examined the changes in photosynthesis, chloroplast morphology and proteomic composition posed in Arabidopsisthaliana chloroplasts after a single or repetitive heat stress treatment over a period of two weeks. We observed that the acclimation is potent in the case of repetitive application of heat stress, while a single stress results in lasting alterations. Moreover, the physiological capacity and its adjustment are dependent on the efficiency of the protein translocation process as judged from the analysis of mutants of the two receptor units of the chloroplast translocon, TOC64, and TOC33. In response to repetitive heat stress, plants without TOC33 accumulate Hsp70 proteins and plants without TOC64 have a higher content of proteins involved in thylakoid structure determination when compared to wild-type plants.


Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Respuesta al Choque Térmico/genética , Proteínas de la Membrana/genética , Arabidopsis/crecimiento & desarrollo , Cloroplastos/genética , Proteínas del Choque Térmico HSP72/genética , Fotosíntesis/genética , Proteómica
15.
Rev Sci Instrum ; 91(3): 034504, 2020 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-32259966

RESUMEN

Plants represent an essential part of future life support systems that will enable human space travel to distant planets and their colonization. Therefore, insights into changes and adaptations of plants in microgravity are of great importance. Despite considerable efforts, we still know very little about how plants respond to microgravity environments on the molecular level, partly due to a lack of sufficient hardware and flight opportunities. The plant Arabidopsis thaliana, the subject of this study, represents a well-studied model organism in gravitational biology, particularly for the analysis of transcriptional and metabolic changes. To overcome the limitations of previous plant hardware that often led to secondary effects and to allow for the extraction not only of RNA but also of phytohormones and proteins, we developed a new experimental platform, called ARABIDOMICS, for exposure and fixation under altered gravity conditions. Arabidopsis seedlings were exposed to hypergravity during launch and microgravity during the free-fall period of the MAPHEUS 5 sounding rocket. Seedlings were chemically fixed inflight at defined time points, and RNA and phytohormones were subsequently analyzed in the laboratory. RNA and phytohormones extracted from the fixed biological samples were of excellent quality. Changes in the phytohormone content of jasmonate, auxin, and several cytokinins were observed in response to hypergravity and microgravity.


Asunto(s)
Arabidopsis/crecimiento & desarrollo , Hipergravedad , Fitocromo/metabolismo , ARN de Planta/metabolismo , Plantones/crecimiento & desarrollo , Ingravidez , Vuelo Espacial
17.
Sci Rep ; 7(1): 14235, 2017 10 27.
Artículo en Inglés | MEDLINE | ID: mdl-29079824

RESUMEN

Seed germination and postgerminative growth of Arabidopsis thaliana and various other plant species are arrested in response to unfavourable environmental conditions by signalling events involving the phytohormone abscisic acid (ABA). In this study, we showed that loss of the seed-specific WRKY DNA-BINDING PROTEIN 43 (WRKY43) conferred increased tolerance towards high salt, high osmolarity and low temperature during seed germination in Arabidopsis. The wrky43 loss of function lines displayed increased inhibition of seed germination in response to exogenous ABA; whereas lines overexpressing WRKY43 were more tolerant towards exogenous ABA. Biochemical analysis of fatty acid composition revealed that loss of WRKY43 increased polyunsaturated fatty acid content in seeds, particularly 18:2Δ9,12 and 18:3Δ9,12,15 in triacylglycerols and phospholipids, indicating an important physiological effect on fatty acid desaturation with ramifications for the tolerance of plants to cold and osmotic stress and possibly, for oilseed engineering. Molecular analyses showed that ABA-induced regulation of FUSCA3, ZAT10 and seed storage proteins were absent in the wrky43 mutant. In summary, WRKY43 encodes for a novel positive regulator of ABA-dependent gene regulation and as a potent modulator of fatty acid desaturation and seed filling, which results in increased tolerance to abiotic stress.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Ácidos Grasos Insaturados/metabolismo , Germinación , Semillas/crecimiento & desarrollo , Factores de Transcripción/metabolismo , Ácido Abscísico/farmacología , Arabidopsis/fisiología , Proteínas de Arabidopsis/genética , Respuesta al Choque por Frío/efectos de los fármacos , Elementos Transponibles de ADN/genética , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Germinación/efectos de los fármacos , Manitol/farmacología , Mutagénesis Insercional/genética , Presión Osmótica/efectos de los fármacos , Fosfolípidos/metabolismo , Estrés Salino/efectos de los fármacos , Semillas/efectos de los fármacos , Cloruro de Sodio/farmacología , Factores de Transcripción/genética , Triglicéridos/metabolismo , Regulación hacia Arriba/efectos de los fármacos
18.
Plant Signal Behav ; 10(11): e1106659, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26479147

RESUMEN

The phytohormone ABA plays a major role during plant development, e.g. seed maturation and seed germination, and during adaptation to abiotic stresses like stomatal aperture regulation. The three closely related WRKY transcription factors WRKY18, WRKY40 and WRKY60 function in ABA signal transduction. We recently demonstrated that WRKY18 and WRKY40 but not WRKY60 localize to nuclear bodies in A. thaliana mesophyll protoplasts. WRKY40, a negative regulator of ABA-dependent inhibition of seed germination, relocalizes from PNBs to the nucleoplasm in the presence of ABA in a dynamic and phosphorylation-dependent manner. We propose that subnuclear relocalization of WRKY40 might constitute a new regulatory mechanism of ABA-dependent modulation of transcription factor activity.


Asunto(s)
Ácido Abscísico/farmacología , Proteínas de Arabidopsis/metabolismo , Núcleo Celular/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Núcleo Celular/efectos de los fármacos , Luz , Modelos Biológicos , Transporte de Proteínas/efectos de los fármacos , Transporte de Proteínas/efectos de la radiación , Transducción de Señal/efectos de los fármacos , Transducción de Señal/efectos de la radiación
19.
Sci Rep ; 5: 13369, 2015 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-26293691

RESUMEN

WRKY18, WRKY40 and WRKY60 are members of the WRKY transcription factor family and function as transcriptional regulators in ABA signal transduction in Arabidopsis thaliana. Here we show that WRKY18 and WRKY40, but not WRKY60, co-localise with PIF3, PIF4 and PHYB to Phytochrome B-containing nuclear bodies (PNBs). Localisation to the PNBs is phosphorylation-dependent and is inhibited by the general Ser/Thr-kinase inhibitor Staurosporine. Upon ABA treatment, WRKY40 relocalises from PNBs to the nucleoplasm in an OST1-dependent manner. This stimulus-induced relocalisation was not observed in response to other abiotic or biotic stimuli, including NaCl, MeJA or flg22 treatment. Bimolecular fluorescence complementation experiments indicate that while PIF3, PIF4 and PHYB physically interact in these bodies, PHYB, PIF3 and PIF4 do not interact with the two WRKY transcription factors, which may suggest a more general role for these bodies in regulation of transcriptional activity.


Asunto(s)
Ácido Abscísico/farmacología , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Núcleo Celular/metabolismo , Factores de Transcripción/metabolismo , Arabidopsis/efectos de los fármacos , Núcleo Celular/efectos de los fármacos , Fluorescencia , Fitocromo B , Hojas de la Planta/metabolismo , Transporte de Proteínas/efectos de los fármacos , Protoplastos/efectos de los fármacos , Protoplastos/metabolismo , Nicotiana/metabolismo
20.
Front Plant Sci ; 6: 1176, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26734055

RESUMEN

During evolution, plants have developed mechanisms to adapt to a variety of environmental stresses, including drought, high salinity, changes in carbon dioxide levels and pathogens. Central signaling hubs and pathways that are regulated in response to these stimuli have been identified. In contrast to these well studied environmental stimuli, changes in transcript, protein and metabolite levels in response to a gravitational stimulus are less well understood. Amyloplasts, localized in statocytes of the root tip, in mesophyll cells of coleoptiles and in the elongation zone of the growing internodes comprise statoliths in higher plants. Deviations of the statocytes with respect to the earthly gravity vector lead to a displacement of statoliths relative to the cell due to their inertia and thus to gravity perception. Downstream signaling events, including the conversion from the biophysical signal of sedimentation of distinct heavy mass to a biochemical signal, however, remain elusive. More recently, technical advances, including clinostats, drop towers, parabolic flights, satellites, and the International Space Station, allowed researchers to study the effect of altered gravity conditions - real and simulated micro- as well as hypergravity on plants. This allows for a unique opportunity to study plant responses to a purely anthropogenic stress for which no evolutionary program exists. Furthermore, the requirement for plants as food and oxygen sources during prolonged manned space explorations led to an increased interest in the identi-fication of genes involved in the adaptation of plants to microgravity. Transcriptomic, proteomic, phosphoproteomic, and metabolomic profiling strategies provide a sensitive high-throughput approach to identify biochemical alterations in response to changes with respect to the influence of the gravitational vector and thus the acting gravitational force on the transcript, protein and metabolite level. This review aims at summarizing recent experimental approaches and discusses major observations.

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