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1.
Foods ; 11(4)2022 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-35206051

RESUMO

Phaeodactylum tricornutum is a model diatom with numerous potential applications in the industry, including the production of high-value carotenoid pigments such as fucoxanthin. This compound is a potent antioxidant currently extracted mainly from brown macroalgae. Fucoxanthin exhibits several biological properties with well-known beneficial effects in the treatment and prevention of lifestyle-related diseases. P. tricornutum offers a valuable alternative to macroalgae for fucoxanthin production as it has a specific productivity that is 10-fold higher as compared with macroalgae. However, production processes still need to be optimised to become a cost-effective alternative. In this work, we investigated the optimal supplementation of nitrate in a cultivation medium that is currently used for P. tricornutum and how this nitrate concentration affects cell growth and fucoxanthin production. It has previously been shown that the addition of sodium nitrate increases productivity, but optimal conditions were not accurately determined. In this report, we observed that the continuous increase in nitrate concentration did not lead to an increase in biomass and fucoxanthin content, but there was rather a window of optimal values of nitrate that led to maximum growth and pigment production. These results are discussed considering both the scale up for industrial production and the profitability of the process, as well as the implications in the cell's metabolism and effects in fucoxanthin production.

2.
Front Plant Sci ; 12: 559967, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33897718

RESUMO

Spatial separation of the photosynthetic reactions is a key feature of C4 metabolism. In most C4 plants, this separation requires compartmentation of photosynthetic enzymes between mesophyll (M) and bundle sheath (BS) cells. The upstream region of the gene encoding the maize PHOSPHOENOLPYRUVATE CARBOXYLASE 1 (ZmPEPC1) has been shown sufficient to drive M-specific ZmPEPC1 gene expression. Although this region has been well characterized, to date, only few trans-factors involved in the ZmPEPC1 gene regulation were identified. Here, using a yeast one-hybrid approach, we have identified three novel maize transcription factors ZmHB87, ZmCPP8, and ZmOrphan94 as binding to the ZmPEPC1 upstream region. Bimolecular fluorescence complementation assays in maize M protoplasts unveiled that ZmOrphan94 forms homodimers and interacts with ZmCPP8 and with two other ZmPEPC1 regulators previously reported, ZmbHLH80 and ZmbHLH90. Trans-activation assays in maize M protoplasts unveiled that ZmHB87 does not have a clear transcriptional activity, whereas ZmCPP8 and ZmOrphan94 act as activator and repressor, respectively. Moreover, we observed that ZmOrphan94 reduces the trans-activation activity of both activators ZmCPP8 and ZmbHLH90. Using the electromobility shift assay, we showed that ZmOrphan94 binds to several cis-elements present in the ZmPEPC1 upstream region and one of these cis-elements overlaps with the ZmbHLH90 binding site. Gene expression analysis revealed that ZmOrphan94 is preferentially expressed in the BS cells, suggesting that ZmOrphan94 is part of a transcriptional regulatory network downregulating ZmPEPC1 transcript level in the BS cells. Based on both this and our previous work, we propose a model underpinning the importance of a regulatory mechanism within BS cells that contributes to the M-specific ZmPEPC1 gene expression.

3.
Support Care Cancer ; 29(4): 1863-1871, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32789624

RESUMO

PURPOSE: To evaluate the association between comorbidities as assessed by the "Adult Comorbidity Evaluation 27" (ACE-27) and the development of severe acute toxicities in patients with head and neck cancer treated with chemoradiotherapy. METHODS: Prospective, single-center cohort of patients with head and neck cancer treated with chemoradiotherapy (cisplatin 100 mg/m2 on days 1, 22, and 43; intensity-modulated radiotherapy 60 to 69.96 gray, in 30 to 33 fractions,) between June 2018 and December 2019. ACE-27 was assessed before the start of treatment. Patients were divided in two groups based on ACE-27 grading (none to mild versus moderate to severe comorbidities). Differences in incidence of severe acute toxicity and change in treatment plan between groups were examined. RESULTS: A total of 101 patients were included: 90.1% were male, and median age was 57 years. ACE-27 grading was none in 6.9% of patients, mild in 52.5%, moderate in 29.7%, and severe in 10.9%. Severe acute toxicities occurred more frequently in patients with moderate to severe comorbidities (75.6% versus 48.3%), with a statically significant difference (p = 0.006, OR 3.314, 95%-CI (1.382-7.944)). In the group with moderate to severe comorbidities, omission of at least one cisplatin cycle (75.6% versus 60.0%) and premature ending of radiotherapy (12.2% versus 5.0%) also occurred more frequently (p ≥ 0.05). CONCLUSION: In patients with head and neck cancer treated with chemoradiotherapy, the presence of moderate to severe comorbidities seems to correlate with higher incidences of severe acute toxicities. ACE-27 may identify patients at higher risk of major toxicities and assist decisions regarding treatment.


Assuntos
Antineoplásicos/efeitos adversos , Quimiorradioterapia/efeitos adversos , Neoplasias de Cabeça e Pescoço/complicações , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos
4.
Plant J ; 99(2): 270-285, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30900785

RESUMO

Compartmentation of photosynthetic reactions between mesophyll and bundle sheath cells is a key feature of C4 photosynthesis and depends on the cell-specific accumulation of major C4 enzymes, such as phosphoenolpyruvate carboxylase 1. The ZmPEPC1 upstream region, which drives light-inducible and mesophyll-specific gene expression in maize, has been shown to keep the same properties when introduced into rice (C3 plant), indicating that rice has the transcription factors (TFs) needed to confer C4 -like gene expression. Using a yeast one-hybrid approach, we identified OsbHLH112, a rice basic Helix-Loop-Helix (bHLH) TF that interacts with the maize ZmPEPC1 upstream region. Moreover, we found that maize OsbHLH112 homologues, ZmbHLH80, and ZmbHLH90, also interact with the ZmPEPC1 upstream region, suggesting that these C4 regulators were co-opted from C3 plants. A transactivation assay in maize mesophyll protoplasts revealed that ZmbHLH80 represses, whereas ZmbHLH90 activates, ZmPEPC1 expression. In addition, ZmbHLH80 was shown to impair the ZmPEPC1 promoter activation caused by ZmbHLH90. We showed that ZmbHLH80 and ZmbHLH90 bind to the same cis-element within the ZmPEPC1 upstream region either as homodimers or heterodimers. The formation of homo- and heterodimers with higher oligomeric forms promoted by ZmbHLH80 may explain its negative effect on gene transcription. Gene expression analysis revealed that ZmbHLH80 is preferentially expressed in bundle sheath cells, whereas ZmbHLH90 does not show a clear cell-specific expression pattern. Altogether, our results led us to propose a model in which ZmbHLH80 contributes to mesophyll-specific ZmPEPC1 gene expression by impairing ZmbHLH90-mediated ZmPEPC1 activation in the bundle sheath cells.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/fisiologia , Proteínas de Plantas/fisiologia , Zea mays/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Regulação da Expressão Gênica de Plantas , Técnicas de Sonda Molecular , Oryza/genética , Fotossíntese/genética , Proteínas de Plantas/genética , Regiões Promotoras Genéticas , Zea mays/metabolismo
5.
Metallomics ; 10(11): 1576-1584, 2018 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-30183791

RESUMO

Cadmium (Cd) was shown to co-localise with calcium (Ca) in oxalate crystals in the stems and leaves of Cd tolerant Gomphrena claussenii, but Cd binding remained unresolved. Using synchrotron radiation X-ray absorption near edge spectroscopy we demonstrate that in oxalate crystals of hydroponically grown G. claussenii the vast majority of Cd is bound to oxygen ligands in oxalate crystals (>88%; Cd-O-C coordination) and the remaining Cd is bound to sulphur ligands (Cd-S-C coordination). Cadmium binding to oxalate does not depend on the amount of Ca supplied or from which organs the crystals originate (stems and mature leaves). By contrast, roots contain no oxalate crystals and therein Cd is bound predominantly by S ligands. The potential to remove Cd by extraction of Cd-rich oxalate crystals from plant material should be tested in phytoextraction or phytomining strategies.


Assuntos
Amaranthaceae/metabolismo , Biomarcadores/metabolismo , Cádmio/metabolismo , Oxalato de Cálcio/metabolismo , Cálcio/metabolismo , Oxalatos/metabolismo , Caules de Planta/metabolismo , Amaranthaceae/crescimento & desenvolvimento , Caules de Planta/crescimento & desenvolvimento
6.
Mol Biol Evol ; 35(7): 1690-1705, 2018 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-29659975

RESUMO

C4 photosynthesis has evolved repeatedly from the ancestral C3 state to generate a carbon concentrating mechanism that increases photosynthetic efficiency. This specialized form of photosynthesis is particularly common in the PACMAD clade of grasses, and is used by many of the world's most productive crops. The C4 cycle is accomplished through cell-type-specific accumulation of enzymes but cis-elements and transcription factors controlling C4 photosynthesis remain largely unknown. Using the NADP-Malic Enzyme (NADP-ME) gene as a model we tested whether mechanisms impacting on transcription in C4 plants evolved from ancestral components found in C3 species. Two basic Helix-Loop-Helix (bHLH) transcription factors, ZmbHLH128 and ZmbHLH129, were shown to bind the C4NADP-ME promoter from maize. These proteins form heterodimers and ZmbHLH129 impairs trans-activation by ZmbHLH128. Electrophoretic mobility shift assays indicate that a pair of cis-elements separated by a seven base pair spacer synergistically bind either ZmbHLH128 or ZmbHLH129. This pair of cis-elements is found in both C3 and C4 Panicoid grass species of the PACMAD clade. Our analysis is consistent with this cis-element pair originating from a single motif present in the ancestral C3 state. We conclude that C4 photosynthesis has co-opted an ancient C3 regulatory code built on G-box recognition by bHLH to regulate the NADP-ME gene. More broadly, our findings also contribute to the understanding of gene regulatory networks controlling C4 photosynthesis.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Regulação da Expressão Gênica de Plantas , Malato Desidrogenase/genética , Zea mays/metabolismo , Fotossíntese , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regiões Promotoras Genéticas , Zea mays/genética
7.
Eur J Rheumatol ; 4(2): 142-144, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28638690

RESUMO

Pigmented villonodular synovitis (PVNS) is a rare proliferative disorder of the synovial membrane. This condition is usually monoarticular, can be locally destructive, and involves muscles, tendons, bursae, bones, and skin. The most commonly affected joints are the knee and hip, followed by the ankle and shoulder. Patients often present with pain, swelling, and joint effusion; however, the duration of symptoms varies. Total synovectomy is the preferred treatment for PVNS. Subtotal synovectomy is a factor of recurrence, and in diffuse PVNS, total excision is very difficult to achieve. Radiotherapy may have an adjunctive role, particularly in incomplete resection or as a treatment of salvation in recurrent cases. This treatment modality has low toxicity levels and enables satisfactory joint function. This is a case report of a rare case of diffuse PVNS of the shoulder that was treated with partial arthroscopic synovectomy and adjuvant radiotherapy. A 74-year-old male patient presented with gradual onset pain, hemarthrosis, and functional impairment of the right shoulder without previous trauma history. Magnetic resonance imaging of the shoulder demonstrated a diffuse synovial thickening that was compatible with PVNS and rotator cuff destruction. The lesion was partially excised by arthroscopy. The patient underwent adjuvant radiation therapy with a total dose of 40 Gy/20 fractions/4 weeks. At the final follow-up, i.e., 1 month after treatment, the patient had increased shoulder mobility and no pain, with a mild change in cutaneous pigmentation. Radiation therapy is safe and effective in treating and preventing recurrence of diffuse PVNS, particularly after incomplete synovectomy.

8.
Plant Physiol ; 169(3): 2275-87, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26381316

RESUMO

Plant roots can sense and respond to a wide diversity of mechanical stimuli, including touch and gravity. However, little is known about the signal transduction pathways involved in mechanical stimuli responses in rice (Oryza sativa). This work shows that rice root responses to mechanical stimuli involve the E3-ubiquitin ligase rice HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE1 (OsHOS1), which mediates protein degradation through the proteasome complex. The morphological analysis of the roots in transgenic RNA interference::OsHOS1 and wild-type plants, exposed to a mechanical barrier, revealed that the OsHOS1 silencing plants keep a straight root in contrast to wild-type plants that exhibit root curling. Moreover, it was observed that the absence of root curling in response to touch can be reverted by jasmonic acid. The straight root phenotype of the RNA interference::OsHOS1 plants was correlated with a higher expression rice ROOT MEANDER CURLING (OsRMC), which encodes a receptor-like kinase characterized as a negative regulator of rice root curling mediated by jasmonic acid. Using the yeast two-hybrid system and bimolecular fluorescence complementation assays, we showed that OsHOS1 interacts with two ETHYLENE-RESPONSE FACTOR transcription factors, rice ETHYLENE-RESPONSIVE ELEMENT BINDING PROTEIN1 (OsEREBP1) and rice OsEREBP2, known to regulate OsRMC gene expression. In addition, we showed that OsHOS1 affects the stability of both transcription factors in a proteasome-dependent way, suggesting that this E3-ubiquitin ligase targets OsEREBP1 and OsEREBP2 for degradation. Our results highlight the function of the proteasome in rice response to mechanical stimuli and in the integration of these signals, through hormonal regulation, into plant growth and developmental programs.


Assuntos
Regulação da Expressão Gênica de Plantas , Mecanotransdução Celular , Oryza/enzimologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ciclopentanos/metabolismo , Etilenos/metabolismo , Oryza/genética , Oryza/crescimento & desenvolvimento , Oryza/fisiologia , Osmose , Oxilipinas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/fisiologia , Interferência de RNA , Técnicas do Sistema de Duplo-Híbrido , Ubiquitina-Proteína Ligases/genética , Ubiquitinas/metabolismo
9.
Proteomics ; 15(1): 124-34, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25283639

RESUMO

Identification of differences between genetically modified plants and their original counterparts plays a central role in risk assessment strategy. Our main goal was to better understand the relevance of transgene presence, genetic, and epigenetic changes induced by transgene insertion, and in vitro culture in putative unintended differences between a transgenic and its comparator. Thus, we have used multiplex fluorescence 2DE coupled with MS to characterize the proteome of three different rice lines (Oryza sativa L. ssp. japonica cv. Nipponbare): a control conventional line (C), an Agrobacterium-transformed transgenic line (Ta) and a negative segregant (NSb). We observed that Ta and NSb appeared identical (with only one spot differentially abundant--fold difference ≥ 1.5), contrasting with the control (49 spots with fold difference ≥ 1.5, in both Ta and NSb vs. control). Given that in vitro culture was the only event in common between Ta and NSb, we hypothesize that in vitro culture stress was the most relevant condition contributing for the observed proteomic differences. MS protein identification support our hypothesis, indicating that Ta and NSb lines adjusted their metabolic pathways and altered the abundance of several stress related proteins in order to cope with in vitro culture.


Assuntos
Oryza/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Eletroforese em Gel Bidimensional , Regulação da Expressão Gênica de Plantas , Espectrometria de Massas , Redes e Vias Metabólicas , Oryza/química , Oryza/genética , Fotossíntese , Proteínas de Plantas/análise , Proteínas de Plantas/genética , Proteínas de Plantas/isolamento & purificação , Plantas Geneticamente Modificadas/química , Plantas Geneticamente Modificadas/genética , Proteômica , Estresse Fisiológico
10.
Acta Med Port ; 27(4): 467-72, 2014.
Artigo em Português | MEDLINE | ID: mdl-25203955

RESUMO

INTRODUCTION: Sometimes Thyroid dysfunction is an underestimated consequence of radiation exposure. The underlying mechanism is not clearly understood, but it is likely to be multifactorial. As so, the specific risk factors associated with the development of secondary radiotherapy hypothyroidism remain undefined. The direct irradiation of the thyroid gland may result more frequently in hypothyroidism. This is an irreversible condition, requiring lifelong treatment and monitoring. OBJECTIVES: To evaluate the incidence of hypothyroidism in patients with head and neck cancer who underwent neck irradiation on an intensive or adjuvant basis and determine whether it is justifiable to integrate the monitoring of parameters for evaluation of thyroid function (TSH, free fraction T3 e free fraction T4 ) in this patient group on the Institutional follow up protocol. MATERIAL AND METHODS: This is an observational, retrospective descriptive study, which comprises a group of 376 patients with head and neck cancer undergoing radiotherapy, on adjuvant or intensive basis, between the years 2007 and 2012, at Portuguese Institute of Oncology of Coimbra, E.P.E. 145 patients met all the inclusion criteria. Standardized rating scales for the definition of hypothyroidism have been used - LENT-SOMA scales (Late Effects Normal Tissues Subjective Objective Management Analysis). Grade 1 or higher was considered as a complication hypothyroidism. RESULTS: The analysis of a cohort of 145 patients was carried out. The most frequent tumor site was the larynx (26.9%). Thirty-two patients received adjuvant radiotherapy and 113 were treated with intensive schemes. The most used radiotherapy technique was intensity modulated (IMRT), performed in 86.2% patients. The overall incidence rate of hypothyroidism at 12 months was 18.6%. The diagnosis for hypothyroidism was done between 9 and 12 months after treatment radiotherapy in 51.9% of the patients with this complication. DISCUSSION: An analysis of the published literature, hypothyroidism is the most common thyroid complication after irradiation and affects a large percentage of patients undergoing cervical radiotherapy with curative intent. It has been shown that the risk of hypothyroidism increases with time after exposure, but the highest incidence appears to be in the first two years after treatment. From our analysis we obtained at 12 months, a rate of incidence of hypothyroidism of 18.6% (16.55% grade 1 and grade 2, 2.1%). CONCLUSIONS: This study found an incidence of hypothyroidism corresponding to the lowest values reported in other published studies. The short duration of follow-up considered in this analysis, may justify these results. With these results and their correlation with the available literature, the authors consider justified and recommend the inclusion of the systematic evaluation of thyroid function in the follow-up protocol of these patients.


Introdução: A disfunção tiroideia constitui uma consequência, por vezes subestimada, da exposição à radiação. O mecanismo subjacente não está claramente esclarecido, mas terá uma origem multifatorial. Os fatores de risco específicos para o desenvolvimento de hipotiroidismo secundário à radioterapia permanecem indeterminados. A irradiação direta da glândula tiroideia pode resultar, com maior frequência, em hipotiroidismo. Este é uma condição irreversível, requerendo monitorização e tratamento permanente. Objetivos: Avaliar a incidência de hipotiroidismo nos doentes portadores de neoplasias da cabeça e pescoço submetidos a irradiação cervical, a título intensivo ou adjuvante, bem como determinar se é justificável a integração no protocolo de seguimento Institucional, de parâmetros laboratoriais (TSH, T3 Livre e T4 Livre) para avaliação da função tiroideia neste grupo de doentes e qual a sua periodicidade. Material e Métodos: Este é um estudo observacional, descritivo, retrospetivo, que engloba um grupo de 376 doentes portadores de neoplasias da cabeça e pescoço, submetidos a tratamento de radioterapia, a título adjuvante ou intensivo, entre os anos de 2007 e 2012, no Instituto Português de Oncologia de Coimbra Francisco Gentil E.P.E. Cumpriram todos os critérios de inclusão 145 doentes. Foram utilizadas escalas de avaliação padronizadas para a definição de hipotiroidismo ­ LENT-SOMA scales (Late Effects Normal Tissues Subjective Objective Management Analysis). Foi considerada como complicação o hipotiroidismo Grau 1 ou superior. Resultados: Procedeu-se à análise de um grupo de 145 doentes. A localização tumoral mais frequente foi a Laringe (26,9%). Trinta e dois doentes efetuaram radioterapia adjuvante e 113 efetuaram esquemas intensivos. A técnica de radioterapia mais utilizada foi a intensidade modulada (IMRT), efetuada em 86,2% doentes. A taxa de incidência global de hipotiroidismo aos 12 meses foi de 18,6%. Em 51,9% dos doentes foi efetuado o diagnóstico de hipotiroidismo entre os 9 e os 12 meses após o tratamento de radioterapia. Discussão: Da análise da literatura publicada, o hipotiroidismo constitui a complicação tiroideia radioinduzida mais frequente e afeta uma grande percentagem de doentes submetidos a radioterapia cervical com intenção curativa. Foi demonstrado que o risco de hipotiroidismo aumenta com o tempo após a exposição, contudo a incidência mais elevada parece ser nos dois primeiros anos após o tratamento. Da nossa análise obtivemos, aos 12 meses uma taxa de incidência global de hipotiroidismo de 18,6%, (grau 1 de 16,55% e grau 2 de 2,1%). Conclusão: Neste estudo foi encontrada uma incidência de hipotiroidismo correspondente aos valores mais baixos descritos em outros estudos publicados. O curto tempo de follow-up considerado nesta análise poderá justificar os resultados obtidos. Face aos resultados obtidos, e correlacionando-os com a literatura disponível, os autores consideram justificável e recomendável a inserção da avaliação sistemática da função tiroideia no protocolo de follow-up destes doentes.


Assuntos
Neoplasias de Cabeça e Pescoço/radioterapia , Hipotireoidismo/epidemiologia , Hipotireoidismo/etiologia , Lesões por Radiação/complicações , Glândula Tireoide/efeitos da radiação , Adolescente , Adulto , Idoso , Feminino , Seguimentos , Humanos , Hipotireoidismo/fisiopatologia , Incidência , Masculino , Pessoa de Meia-Idade , Lesões por Radiação/fisiopatologia , Radioterapia/efeitos adversos , Estudos Retrospectivos , Glândula Tireoide/fisiopatologia , Adulto Jovem
11.
Plant Mol Biol ; 82(4-5): 439-55, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23703395

RESUMO

High salinity causes remarkable losses in rice productivity worldwide mainly because it inhibits growth and reduces grain yield. To cope with environmental changes, plants evolved several adaptive mechanisms, which involve the regulation of many stress-responsive genes. Among these, we have chosen OsRMC to study its transcriptional regulation in rice seedlings subjected to high salinity. Its transcription was highly induced by salt treatment and showed a stress-dose-dependent pattern. OsRMC encodes a receptor-like kinase described as a negative regulator of salt stress responses in rice. To investigate how OsRMC is regulated in response to high salinity, a salt-induced rice cDNA expression library was constructed and subsequently screened using the yeast one-hybrid system and the OsRMC promoter as bait. Thereby, two transcription factors (TFs), OsEREBP1 and OsEREBP2, belonging to the AP2/ERF family were identified. Both TFs were shown to bind to the same GCC-like DNA motif in OsRMC promoter and to negatively regulate its gene expression. The identified TFs were characterized regarding their gene expression under different abiotic stress conditions. This study revealed that OsEREBP1 transcript level is not significantly affected by salt, ABA or severe cold (5 °C) and is only slightly regulated by drought and moderate cold. On the other hand, the OsEREBP2 transcript level increased after cold, ABA, drought and high salinity treatments, indicating that OsEREBP2 may play a central role mediating the response to different abiotic stresses. Gene expression analysis in rice varieties with contrasting salt tolerance further suggests that OsEREBP2 is involved in salt stress response in rice.


Assuntos
Oryza/metabolismo , Fator de Transcrição AP-2/metabolismo , Ácido Abscísico/farmacologia , Secas , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/genética , Oryza/efeitos dos fármacos , Oryza/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Cloreto de Sódio/farmacologia , Fator de Transcrição AP-2/genética
12.
J Exp Bot ; 63(10): 3643-56, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22412187

RESUMO

Plants have evolved several mechanisms in order to cope with adverse environmental conditions. The transcription factors (TFs) belonging to the DREB1/CBF subfamily have been described as major regulators of the plant responses to different abiotic stresses. This study focused on the rice gene OsDREB1B, initially described as highly and specifically induced by cold. However, here it is shown that OsDREB1B is not only induced by low temperatures, but also by drought and mechanical stress. In order to identify novel TFs that bind to its promoter, a yeast one-hybrid system was used to screen a cold-induced cDNA expression library. Thereby seven novel Zn-finger TFs were identified that bind to the promoter of OsDREB1B. Among them, there were four Zn-finger homeodomain (ZF-HD) and three C(2)H(2)-type Zn-finger TFs. Gene expression studies showed that these TFs are differentially regulated at transcriptional level by different abiotic stress conditions, which is illustrative of the crosstalk between stress signalling pathways. Protein-protein interaction studies revealed the formation of homo- and heterodimers among the ZF-HD TFs identified, but not for the C(2)H(2)-type. Using a transactivation assay in Arabidopsis protoplasts, all the TFs identified repressed the expression of the reporter gene, driven by the promoter of OsDREB1B. This assay also showed that the dimerization observed between the ZF-HD TFs may play a role on their transactivation activity. The results here presented suggest a prominent role of Zn-finger TFs in the regulation of OsDREB1B.


Assuntos
Regulação da Expressão Gênica de Plantas , Oryza/fisiologia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo , Dedos de Zinco , Genes Reguladores , Oryza/química , Oryza/genética , Proteínas de Plantas/genética , Regiões Promotoras Genéticas , Estresse Fisiológico , Fatores de Transcrição/genética
13.
OMICS ; 15(12): 839-57, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22136664

RESUMO

Plant growth and crop production are highly reduced by adverse environmental conditions and rice is particularly sensitive to abiotic stresses. Plants have developed a number of different mechanisms to respond and try to adapt to abiotic stress. Plant response to stress such as drought, cold, and high salinity, implies rapid and coordinated changes at transcriptional level of entire gene networks. During the last decade many transcription factors, belonging to different families, have been shown to act as positive or negative regulators of stress responsive genes, thus playing an extremely important role in stress signaling. More recently, epigenetic mechanisms have been also involved in the regulation of the stress responsive genes. In this review, we have performed a comprehensive analysis of the rice transcription factors reported so far as being involved in abiotic stress responses. The impact of abiotic stresses on epigenomes is also addressed. Finally, we update the connections made so far between DNA-binding transcription factors (TFs), and epigenetic mechanisms (DNA methylation and histones methylation or acetylation) emphasizing an integrative view of transcription regulation.


Assuntos
Epigênese Genética , Regulação da Expressão Gênica de Plantas , Oryza/genética , Estresse Fisiológico/genética , Fatores de Transcrição/metabolismo , Transcrição Gênica , Metilação de DNA , Histonas/metabolismo , Oryza/metabolismo
14.
Alethéia ; (24): 69-80, jul.-dez. 2006.
Artigo em Português | Index Psicologia - Periódicos | ID: psi-32899

RESUMO

Este trabalho tem por objetivo retomar obra de 1990, intitulada Riobaldo Rosa, a vereda junguiana do Grande sertão, a fim de evidenciar a hipótese de que o romance de João Guimarães Rosa, Grande sertão: veredas comporta uma interpretação junguiana. Essa hipótese visa a demonstrar que a 'viagem' de Riobaldo, o protagonista do romance, pode ser analisada como um processo de individuação, com as suas diferentes etapas. A fim de facilitar a leitura, este artigo virá seguido de um glossário dos principais conceitos de Carl Jung usados no texto.Por fim, é necessário ter em mente que se trata de um trabalho de crítica literária, e não de psicologia, o que necessariamente implica ser o processo de individuação nele tratado um processo finito, pertencendo àquele personagem específico, e que se encerra no final da narrativa, ao contrário do de uma pessoa de carne e osso, para a qual a individuação é um processo em perene renovação.(AU)


Assuntos
Literatura , Teoria Junguiana , Individuação
15.
Aletheia ; (24): 69-80, jul.-dez. 2006.
Artigo em Português | LILACS | ID: lil-447756

RESUMO

Este trabalho tem por objetivo retomar obra de 1990, intitulada Riobaldo Rosa, a vereda junguiana do Grande sertão, a fim de evidenciar a hipótese de que o romance de João Guimarães Rosa, Grande sertão: veredas comporta uma interpretação junguiana. Essa hipótese visa a demonstrar que a 'viagem' de Riobaldo, o protagonista do romance, pode ser analisada como um processo de individuação, com as suas diferentes etapas. A fim de facilitar a leitura, este artigo virá seguido de um glossário dos principais conceitos de Carl Jung usados no texto.Por fim, é necessário ter em mente que se trata de um trabalho de crítica literária, e não de psicologia, o que necessariamente implica ser o processo de individuação nele tratado um processo finito, pertencendo àquele personagem específico, e que se encerra no final da narrativa, ao contrário do de uma pessoa de carne e osso, para a qual a individuação é um processo em perene renovação.


Assuntos
Individuação , Teoria Junguiana , Literatura
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