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1.
Res Social Adm Pharm ; 17(11): 2006-2014, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-33775557

RESUMO

AIMS: To explore the impact of a prescribing feedback intervention on insulin prescribing. METHODS: This was a mixed-methods study in a hospital setting. An insulin prescribing feedback intervention was delivered verbally and in writing to twelve doctors. Insulin prescribing error frequency was compared to ten doctors who had not received the feedback intervention. Insulin prescribing was audited over four weeks at the start and end of the intervention period. Semi-structured interviews were conducted with participating doctors who had received feedback, and qualitative data analysed thematically to explore the impact of the intervention on their prescribing practice. RESULTS: Prescribing data were collected on 370 insulin prescriptions with 241 errors identified. A significant reduction (χ2 = 22.6, p=<0.05) in insulin prescribing error frequency was observed in the intervention group, with a non-significant increase reported in the control group. Feedback was received positively and considered valuable by doctors, supporting development of their knowledge and skills and encouraging reflection on their prescribing performance. Doctors described enhanced confidence in insulin prescribing and a desire to improve as a prescriber and avoid harm, with feedback raising awareness of their development needs. Prescribers also described enhanced team work, with greater information and feedback seeking behavior to inform future prescribing decisions. CONCLUSIONS: Feedback has potential to improve insulin prescribing and is a valued and acceptable process intervention for doctors. The impact on insulin prescribing practice is varied and complex influencing the capability, opportunity and motivation of prescribers to adapt and evolve their behavior in response to ongoing feedback.


Assuntos
Insulina , Farmacêuticos , Prescrições de Medicamentos , Retroalimentação , Hospitais , Humanos , Erros de Medicação/prevenção & controle , Projetos Piloto
2.
Nat Commun ; 10(1): 83, 2019 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-30622257

RESUMO

Mitochondrial topoisomerase IB (TOP1MT) is a nuclear-encoded topoisomerase, exclusively localized to mitochondria, which resolves topological stress generated during mtDNA replication and transcription. Here, we report that TOP1MT is overexpressed in cancer tissues and demonstrate that TOP1MT deficiency attenuates tumor growth in human and mouse models of colon and liver cancer. Due to their mitochondrial dysfunction, TOP1MT-KO cells become addicted to glycolysis, which limits synthetic building blocks and energy supply required for the proliferation of cancer cells in a nutrient-deprived tumor microenvironment. Mechanistically, we show that TOP1MT associates with mitoribosomal subunits, ensuring optimal mitochondrial translation and assembly of oxidative phosphorylation complexes that are critical for sustaining tumor growth. The TOP1MT genomic signature profile, based on Top1mt-KO liver cancers, is correlated with enhanced survival of hepatocellular carcinoma patients. Our results highlight the importance of TOP1MT for tumor development, providing a potential rationale to develop TOP1MT-targeted drugs as anticancer therapies.


Assuntos
Carcinogênese/patologia , Carcinoma Hepatocelular/patologia , DNA Topoisomerases Tipo I/metabolismo , Neoplasias Hepáticas Experimentais/patologia , Neoplasias Hepáticas/patologia , Mitocôndrias/metabolismo , Biossíntese de Proteínas , Animais , Carcinógenos/toxicidade , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/mortalidade , Núcleo Celular/metabolismo , Proliferação de Células , DNA Topoisomerases Tipo I/genética , DNA Mitocondrial/genética , DNA Mitocondrial/isolamento & purificação , Conjuntos de Dados como Assunto , Metabolismo Energético , Feminino , Fibroblastos , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Glicólise , Células HCT116 , Humanos , Fígado/citologia , Fígado/metabolismo , Fígado/patologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas Experimentais/induzido quimicamente , Neoplasias Hepáticas Experimentais/genética , Neoplasias Hepáticas Experimentais/metabolismo , Masculino , Camundongos , Camundongos Knockout , Camundongos Nus , Mitocôndrias/patologia , Prognóstico , Análise de Sobrevida , Ensaios Antitumorais Modelo de Xenoenxerto
3.
Bioinspir Biomim ; 12(5): 055003, 2017 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-28691920

RESUMO

A novel approach to fabricating and testing artificial insect wings has been developed. Utilizing these new techniques, locally harvested hawk moth (Manduca sexta) forewings are compared to engineered forewings with varying wing structures. A number of small, flexible engineered forewings were fabricated with identical planform size and shape but with variations in camber, ribbing, thickness and composition. A series of static and dynamic assessments compares the forewings in terms of structure and performance. Data from these experiments show that the fabrication method can produce artificial forewings with similar properties to that of M. sexta. Flexural stiffness (EI) data shows a maximum percent difference of 41% between the left and right natural M. sexta forewings, whereas engineered forewings have a maximum percent difference of 18%. When deflection is induced from the ventral side of the forewing, EI values are at least 9.1% higher than when it is induced from the dorsal side. According to simulations, approximately 57% of this difference can be attributed to the camber of the forewings. Fabricated forewings produced comparable amounts of lift to natural M. sexta forewings (1.00 gF and 0.96 gF at 25 Hz flapping frequency respectively).


Assuntos
Aeronaves/instrumentação , Materiais Biomiméticos , Voo Animal/fisiologia , Manduca/anatomia & histologia , Miniaturização , Modelos Anatômicos , Asas de Animais/anatomia & histologia , Animais , Aviação , Desenho de Equipamento , Dureza , Manduca/fisiologia , Modelos Animais , Modelos Biológicos , Reprodutibilidade dos Testes , Asas de Animais/fisiologia
4.
Environ Manage ; 58(1): 31-47, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27094441

RESUMO

Organizations at the local and regional scales often face the challenge of developing policy mechanisms rapidly and concurrently, whether in response to expanding mandates, newly identified threats, or changes in the political environment. In the Canadian Province of Ontario, rapid, concurrent policy development was considered desirable by 19 regional organizations tasked with developing policies for protection of drinking water sources under very tight and highly prescribed mandates. An explicit policy transfer approach was used by these organizations. Policy transfer refers to using knowledge of policies, programs, and institutions in one context in the development of policies, programs, and institutions in another. This paper assesses three online mechanisms developed to facilitate policy transfer for source water protection in Ontario. Insights are based on a survey of policy planners from the 19 regional organizations who used the three policy transfer tools, supplemented by an analysis of three policies created and transferred among the 19 regional source water protection organizations. Policy planners in the study indicated they had used policy transfer to develop source protection policies for their regions-a finding confirmed by analysis of the text of policies. While the online policy transfer tools clearly facilitated systematic policy transfer, participants still preferred informal, direct exchanges with their peers in other regions over the use of the internet-based policy transfer mechanisms created on their behalf.


Assuntos
Conservação dos Recursos Naturais/métodos , Política Ambiental/tendências , Formulação de Políticas , Recursos Hídricos , Conservação dos Recursos Naturais/legislação & jurisprudência , Política Ambiental/legislação & jurisprudência , Humanos , Ontário , Organizações , Política Pública
5.
Br Dent J ; 212(1): 4-5, 2012 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-22240668
6.
Psychooncology ; 20(8): 841-50, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20568085

RESUMO

OBJECTIVE: The objective of this study was to assess the prevalence and associated factors of sexual activity, sexual problems or sexual satisfaction in French early-stage breast cancer survivors (BCS). METHODS: Eight hundred and fifty eligible, post-treatment (6 months-5 years) female patients, aged 18-70 years, randomly selected from a consultation list, were invited to fill in questionnaires exploring quality of life (EORTC QLQ-C30 and QLQ-BR23), body image scale, and sexuality (Sexual Activity Questionnaire-SAQ; Relationship and Sexuality Scale; French Sexual Behaviour Survey-CSF). RESULTS: Fifty-three percent of BCS agreed to participate. Participating women (n=378) were younger, more often premenopausal at diagnosis and with a more recent diagnosis than non-respondents. The prevalence of sexual problems was significantly higher in BCS compared with adjusted data from a French female representative sample (p<0.0001). In logistic regression, no sexual activity (R(2) =0.37) or sexual dissatisfaction (R(2) =0.28) were associated with the feeling of emotional separation in the couple or of partner's fear of sexual intercourse, lower emotional functioning, poorer body image, or co-morbidities. In sexually active women (71% of respondents), lower frequency of sexual activity (R(2) =0.26), lower sexual pleasure (R(2) =0.22), or higher sexual discomfort (R(2) =0.22) were associated with the feeling of emotional separation in the couple or of partner's fear of sexual intercourse, lower emotional functioning, age (>50 years), nausea, or insomnia (all Hosmer-Lemeshow tests: p=NS). CONCLUSIONS: Psychological factors including the perception of the couple relationship appeared prominent in BCS women's experience of sexual problems.


Assuntos
Neoplasias da Mama/complicações , Disfunções Sexuais Psicogênicas/etiologia , Adolescente , Adulto , Idoso , Neoplasias da Mama/psicologia , Neoplasias da Mama/terapia , Distribuição de Qui-Quadrado , Feminino , França/epidemiologia , Humanos , Modelos Logísticos , Pessoa de Meia-Idade , Prevalência , Testes Psicológicos , Fatores de Risco , Comportamento Sexual/psicologia , Disfunções Sexuais Fisiológicas/epidemiologia , Disfunções Sexuais Fisiológicas/etiologia , Disfunções Sexuais Fisiológicas/psicologia , Disfunções Sexuais Psicogênicas/epidemiologia , Disfunções Sexuais Psicogênicas/psicologia , Fatores Socioeconômicos , Inquéritos e Questionários , Adulto Jovem
7.
Leukemia ; 23(8): 1446-54, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19322212

RESUMO

Omacetaxine mepesuccinate (formerly homoharringtonine) is a molecule with a mechanism of action that is different from tyrosine kinase inhibitors, and its activity in chronic myeloid leukemia (CML) seems to be independent of the BCR-ABL mutation status. Using BCR-ABL-expressing myelogenous and lymphoid cell lines and mouse models of CML and B-cell acute lymphoblastic leukemia (B-ALL) induced by wild-type BCR-ABL or T315I mutant-BCR-ABL, we evaluated the inhibitory effects of omacetaxine on CML and B-ALL. We showed that more than 90% of the leukemic stem cells were killed after treatment with omacetaxine in vitro. In contrast, less than 9 or 25% of the leukemic stem cells were killed after treating with imatinib or dasatinib, respectively. After 4 days of treatment of CML mice with omacetaxine, Gr-1(+)myeloid leukemia cells decreased in the peripheral blood of the treated CML mice. In the omacetaxine-treated B-ALL mice, only 0.8% of the B220(+)leukemia cells were found in peripheral blood, compared with 34% of the B220(+)leukemia cells in the placebo group. Treatment with omacetaxine decreased the number of leukemia stem cells and prolonged the survival of mice with BCR-ABL-induced CML or B-ALL.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Harringtoninas/farmacologia , Leucemia de Células B/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patologia , Animais , Antineoplásicos Fitogênicos/uso terapêutico , Linhagem Celular Tumoral/efeitos dos fármacos , Proteínas de Fusão bcr-abl/genética , Proteínas de Fusão bcr-abl/fisiologia , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico HSP90/biossíntese , Proteínas de Choque Térmico HSP90/genética , Harringtoninas/uso terapêutico , Mepesuccinato de Omacetaxina , Humanos , Células K562/efeitos dos fármacos , Leucemia de Células B/sangue , Leucemia de Células B/patologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Quimera por Radiação , Proteínas Recombinantes de Fusão/fisiologia , Transdução Genética
8.
J La State Med Soc ; 157(5): 269-72, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16374972

RESUMO

West Nile virus (WNV) was first detected in Louisiana during August of 2001. An outbreak of 204 human cases of neuro-invasive disease (NID) and 25 deaths occurred in 2002. In the 2 years following, lower numbers of human cases were identified (101 NID cases in 2003 and 84 in 2004) but intense localized foci were observed. The incidence of NID has been particularly high in the elderly (65 years and older). The distribution of West Nile cases has consisted of sporadic cases with a few very intense foci. Annually, human cases have occurred from June through December, with a peak number of new cases in August. As compared with other WNV serosurveys conducted in the United States, it appears that the WNV seroprevalence in Louisiana is not elevated.


Assuntos
Febre do Nilo Ocidental/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Louisiana/epidemiologia , Masculino , Pessoa de Meia-Idade , Vigilância da População , Estudos Soroepidemiológicos , Taxa de Sobrevida
9.
Plant J ; 26(2): 229-36, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11389763

RESUMO

The timing of flowering is important for the reproductive success of plants. Here we describe the identification and characterization of a new MADS-box gene, FLOWERING LOCUS M (FLM), which is involved in the transition from vegetative to reproductive development. FLM is similar in amino-acid sequence to FLC, another MADS-box gene involved in flowering-time control. flm mutants are early flowering in both inductive and non-inductive photoperiods, and flowering time is sensitive to FLM dosage. FLM overexpression produces late-flowering plants. Thus FLM acts as an inhibitor of flowering. FLM is expressed in areas of cell division such as root and shoot apical regions and leaf primordia.


Assuntos
Proteínas de Ligação a DNA/genética , Plantas/genética , Fatores de Transcrição/genética , Sequência de Aminoácidos , DNA de Plantas , Proteínas de Ligação a DNA/classificação , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Proteínas de Domínio MADS , Dados de Sequência Molecular , Mutação , Fenótipo , Fotoperíodo , Desenvolvimento Vegetal , Proteínas de Plantas , Raízes de Plantas/genética , Caules de Planta/genética , Plantas Geneticamente Modificadas , Splicing de RNA , RNA de Plantas , Reprodução/genética , Fatores de Tempo , Fatores de Transcrição/classificação
10.
Plant Cell ; 13(4): 935-41, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11283346

RESUMO

The MADS domain--containing transcription factor FLOWERING LOCUS C (FLC) acts as an inhibitor of flowering and is a convergence point for several pathways that regulate flowering time in Arabidopsis. In naturally occurring late-flowering ecotypes, the FRIGIDA (FRI) gene acts to increase FLC levels, whereas the autonomous floral promotion pathway and vernalization act to reduce FLC expression. Previous work has shown that the Landsberg erecta allele of FLC, which is not a null allele, is able to partially suppress the late-flowering phenotype of FRIGIDA and mutations in the autonomous pathway. In this study, using a null allele of FLC, we show that the late-flowering phenotype of FRIGIDA and autonomous pathway mutants are eliminated in the absence of FLC activity. In addition, we have found that the downregulation of SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 by FRI and autonomous pathway mutants also is mediated by FLC. Complete loss of FLC function, however, does not eliminate the effect of vernalization. Thus, FRI and the autonomous pathway may act solely to regulate FLC expression, whereas vernalization is able to promote flowering via FLC-dependent and FLC-independent mechanisms.


Assuntos
Proteínas de Arabidopsis , Arabidopsis/genética , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Homeodomínio/genética , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Arabidopsis/metabolismo , Arabidopsis/fisiologia , Northern Blotting , Temperatura Baixa , Proteínas de Ligação a DNA/metabolismo , Regulação para Baixo , Genes Supressores , Proteínas de Homeodomínio/metabolismo , Proteínas de Domínio MADS , Mutação , Fenótipo , Proteínas de Plantas/metabolismo , RNA de Plantas/análise , Fatores de Transcrição/metabolismo
11.
Am J Obstet Gynecol ; 184(4): 538-43, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11262450

RESUMO

OBJECTIVE: Our purpose was to determine the rates of recurrence, persistence, and progression of cervical intraepithelial neoplasia in women who were seropositive for human immunodeficiency virus after excisional therapy with and without highly active antiretroviral therapy. STUDY DESIGN: The records of 118 women with cervical intraepithelial neoplasia, 56 of whom were infected with human immunodeficiency virus and 62 of whom were not infected, were examined to compare outcomes. Demographic, behavioral, and clinical indices were analyzed. RESULTS: Of 54 women infected with human immunodeficiency virus, 31 (57.4%) had persistent or recurrent cervical intraepithelial neoplasia, in comparison with 10 (16.7%) of 60 noninfected women (P <.01). Progression occurred in 4 (16.7%) of 54 in the infected group and in 3 (5.0%) of 60 in the noninfected group (P <.05). In 21 (60.0%) of 35 infected women, in comparison with 8 (32%) of 25 noninfected women, disease persisted 6 months after diagnosis if treatment was not given (P <.05). Of 19 infected women, 10 (52.6%) had recurrent disease after treatment, compared with 2 (5.7%) of 35 noninfected women (P <.01). Risk factors for recurrence in women who were seropositive for human immunodeficiency virus included margin involvement of specimens obtained by loop electrosurgical excision (87.5% vs 20.0%l; P <.05). Exposure to highly active antiretroviral therapy, including therapy with protease inhibitors, was associated with a lower recurrence or persistence rate (17.6% vs. 70.3%; P <.05) and a lower progression rate (0% vs. 24%; P <.05). CONCLUSION: Women infected with human immunodeficiency virus had high rates of recurrent and persistent cervical intraepithelial neoplasia despite standard therapy. Low CD4(+) levels and margin involvement of specimens obtained by loop electrosurgical excision are risk factors for recurrence. The use of highly active antiretroviral therapy is associated with a lower risk of recurrence, persistence, and progression of cervical intraepithelial neoplasia.


Assuntos
Terapia Antirretroviral de Alta Atividade , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Displasia do Colo do Útero/complicações , Displasia do Colo do Útero/cirurgia , Adulto , Contagem de Linfócito CD4 , Conização , Eletrocirurgia , Feminino , Infecções por HIV/transmissão , Inibidores da Protease de HIV/uso terapêutico , Soropositividade para HIV/complicações , Humanos , Recidiva , Estudos Retrospectivos , Fatores de Risco , Abuso de Substâncias por Via Intravenosa , Displasia do Colo do Útero/patologia
12.
Environ Manage ; 27(1): 27-35, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11083906

RESUMO

Initiatives in the Neponset, Ipswich, and Sudbury-Assabet-Concord watersheds highlight how watershed-scale innovation in engaging nongovernment participants is influenced, but not dominated, by the statewide program, the Massachusetts Watershed Initiative. The presence or absence of three elements--external support, process, and issue--and the order in which they occur, shape the viability of collaborative watershed-scale management initiatives. External support includes providing personnel or funding from outside an initiative. Process is the interaction among individuals undertaking watershed-wide policy development and/or implementation. An issue is an attention-requiring concern, vital to a watershed, that can most effectively be addressed by a coordinated strategy among different parties. A process generated by an issue is sustainable and amenable to enhancement through external support. The contribution of external support is most apparent when outside assistance is provided after an issue has crystallized into clear problem needs that can be addressed through specific research projects or implementation activities. Process is central in shaping issues, utilizing external support, and generating management results. The outcomes of voluntary processes in the three watershed initiatives highlight how the evolution of the Massachusetts Watershed Initiative leads to, and depends upon, the development of watershed-scale initiatives.


Assuntos
Conservação dos Recursos Naturais/legislação & jurisprudência , Formulação de Políticas , Poluição da Água/prevenção & controle , Animais , Humanos , Relações Interinstitucionais , Massachusetts , Política Pública , Governo Estadual
13.
Science ; 290(5490): 344-7, 2000 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-11030654

RESUMO

Vernalization, the acceleration of flowering by a long period of cold temperature, ensures that many plants overwinter vegetatively and flower in spring. In Arabidopsis, allelic variation at the FRIGIDA (FRI) locus is a major determinant of natural variation in flowering time. Dominant alleles of FRI confer late flowering, which is reversed to earliness by vernalization. We cloned FRI and analyzed the molecular basis of the allelic variation. Most of the early-flowering ecotypes analyzed carry FRI alleles containing one of two different deletions that disrupt the open reading frame. Loss-of-function mutations at FRI have thus provided the basis for the evolution of many early-flowering ecotypes.


Assuntos
Proteínas de Arabidopsis , Arabidopsis/genética , Genes de Plantas , Variação Genética , Proteínas de Plantas/genética , Alelos , Substituição de Aminoácidos , Arabidopsis/fisiologia , Clonagem Molecular , Genes Recessivos , Mutação , Fases de Leitura Aberta , Proteínas de Plantas/química , Proteínas de Plantas/fisiologia , Reação em Cadeia da Polimerase , Polimorfismo Genético , Deleção de Sequência , Temperatura
14.
Am J Kidney Dis ; 36(1): E4, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10873903

RESUMO

We describe two patients with sarcoidosis with lesions of granulomatous interstitial nephritis (GIN) and postinfectious glomerulonephritis (GN). Both patients presented with heavy proteinuria, hematuria, and renal failure. Renal histology in both showed GIN and glomerular changes of proliferative GN with hump-like subepithelial deposits by electron microscopy of postinfectious GN. Antecedent history of pneumonia was present in one, and ASO titer was elevated in the other. The proteinuria and azotemia improved in both with steroid therapy. Reports of "postinfectious" or diffuse proliferative GN in patients with sarcoidosis are rare. The authors are unaware of reports of concomitant sarcoid GIN and postinfectious GN. Although acute renal insufficiency or failure can occur with GIN or other more common renal lesions primary glomerular disease should be considered in patients with sarcoidosis who present with renal dysfunction. This is a US government work. There are no restrictions on its use.


Assuntos
Injúria Renal Aguda/diagnóstico , Glomerulonefrite/diagnóstico , Nefropatias/diagnóstico , Sarcoidose/diagnóstico , Adulto , Biópsia , Diagnóstico Diferencial , Glomerulonefrite/microbiologia , Humanos , Infecções/complicações , Rim/patologia , Masculino
15.
Eat Disord ; 8(4): 311-29, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-27177303

RESUMO

Eating scales vary enormously in focus, ease, response format, and readability. As part of a larger study related to ethnicity and eating scales, we examined differences in eating scales to determine whether some scales may be more global and culture free in application than others. Ease of readability is related to the educational and cultural background of those to whom the scales are administered. Thus, 30 years of psychological literature (1968-1997) was reviewed; 40 eating disorder scales were found and requested from their authors. Using those who responded, 19 major scales were compared by focus, response format, validity, length, structure, reading level, and reading complexity. As expected, scales vary enormously in focus, length, content, and response format. Readability (as grade level) ranged from a high of 10.6 to a low of 1.1; 70% of the rated scales were rated as "highly readable."

16.
Plant J ; 20(1): 67-77, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10571866

RESUMO

We have analysed the circadian rhythm of Arabidopsis thaliana leaf movements in the accession Cvi from the Cape Verde Islands, and in the commonly used laboratory strains Columbia (Col) and Landsberg (erecta) (Ler), which originated in Northern Europe. The parental lines have similar rhythmic periods, but the progeny of crosses among them reveal extensive variation for this trait. An analysis of 48 Ler/Cvi recombinant inbred lines (RILs) and a further 30 Ler/Col RILs allowed us to locate four putative quantitative trait loci (QTLs) that control the period of the circadian clock. Near-isogenic lines (NILs) that contain a QTL in a small, defined chromo- somal region allowed us to confirm the phenotypic effect and to map the positions of three period QTLs, designated ESPRESSO, NON TROPPO and RALENTANDO. Quantitative trait loci at the locations of RALENTANDO and of a fourth QTL, ANDANTE, were identified in both Ler/Cvi and Ler/Col RIL populations. Some QTLs for circadian period are closely linked to loci that control flowering time, including FLC. We show that flc mutations shorten the circadian period such that the known allelic variation in the MADS-box gene FLC can account for the ANDANTE QTL. The QTLs ESPRESSO and RALENTANDO identify new genes that regulate the Arabidopsis circadian system in nature, one of which may be the flowering-time gene GIGANTEA.


Assuntos
Arabidopsis/genética , Ritmo Circadiano/genética , Genes de Plantas , Alelos , Arabidopsis/fisiologia , Mapeamento Cromossômico , Cruzamentos Genéticos , Ligação Genética , Homeostase , Movimento , Mutação , Folhas de Planta/fisiologia , Característica Quantitativa Herdável
17.
Dev Genet ; 25(3): 194-8, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10528260

RESUMO

The Arabidopsis mutant ga1-3 contains a deletion in an enzyme that catalyzes an early step in the synthesis of gibberellic acid. It has been shown that ga1-3 mutant plants cannot flower under 8-h short-day (SD) conditions, even after vernalization. In this article, we present data demonstrating that the ga1-3 mutation does not block the response to vernalization in intermediate photoperiods or in long-day conditions in a late-flowering, vernalization-responsive background. Thus, GA may not have a direct role in the vernalization response in Arabidopsis, but it may be required for an alternate pathway that promotes flowering in noninductive photoperiods.


Assuntos
Arabidopsis/genética , Giberelinas/biossíntese , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Temperatura Baixa , Giberelinas/genética , Mutação , Fotoperíodo
19.
Plant Cell ; 11(5): 949-56, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10330478

RESUMO

Winter-annual ecotypes of Arabidopsis are relatively late flowering, unless the flowering of these ecotypes is promoted by exposure to cold (vernalization). This vernalization-suppressible, late-flowering phenotype results from the presence of dominant, late-flowering alleles at two loci, FRIGIDA (FRI) and FLOWERING LOCUS C (FLC). In this study, we report that flc null mutations result in early flowering, demonstrating that the role of active FLC alleles is to repress flowering. FLC was isolated by positional cloning and found to encode a novel MADS domain protein. The levels of FLC mRNA are regulated positively by FRI and negatively by LUMINIDEPENDENS. FLC is also negatively regulated by vernalization. Overexpression of FLC from a heterologous promoter is sufficient to delay flowering in the absence of an active FRI allele. We propose that the level of FLC activity acts through a rheostat-like mechanism to control flowering time in Arabidopsis and that modulation of FLC expression is a component of the vernalization response.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Arabidopsis/genética , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica de Plantas , Proteínas Repressoras/genética , Fatores de Transcrição/genética , Clonagem Molecular , Temperatura Baixa , Genes de Plantas , Proteínas de Domínio MADS , Modelos Biológicos , Mutagênese , Proteínas de Plantas , Reprodução/genética , Fatores de Tempo
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