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AIMS: Obesity is a leading contributor to global morbidity and mortality. Short sleep duration is significantly associated with the incidence of obesity, however, it remains unclear whether this relationship is influenced by sex. The purpose of this meta-analysis was to systematically evaluate the evidence of whether the association between short sleep duration and obesity differs between males and females. DATA SYNTHESIS: The protocol was registered with PROSPERO (CRD42023374205). From inception through June 2023, Medline, Embase and Web of Science databases were searched for longitudinal cohort studies with minimum 12 months of observation. The quality of studies was assessed using the Newcastle-Ottawa Quality Assessment for Cohort Studies. Results were pooled using a random effects model. Results are expressed as ratio of odds ratios (ROR) with 95% confidence interval (CI). ROR directly estimates the relative strength of the association of interest (measured as odds ratio [OR] between females and males). Sensitivity analysis was performed and inconsistency between studies was assessed using I2 statistics. A total of 4582 articles were retrieved with the search strategy, of which 6 were included. The meta-analysis indicated that the association between short sleep duration and obesity incidence was statistically significant in both men [OR 1.26 (95% CI 1.13-1.40)] and women [OR 1.36 (95% CI 1.16-1.59)]. However, it did not differ significantly between sexes ROR (women/men) 1.04 (95%CI 0.79-1.36; I2 20.1%). CONCLUSIONS: This meta-analysis indicates that women and men who subjectively report short sleep duration have similarly increased risks of incident obesity.
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BACKGROUND: The prevalence of obesity is rising globally and effective strategies to treat obesity are needed. Intermittent fasting, a dietary intervention for weight management, has received growing interest from the general public, as well as healthcare professionals, as a form of lifestyle intervention. METHODS: We executed a rapid review using PUBMED database to identify systematic reviews that examined the impact of intermittent fasting on metabolic indices, published between 2011 and 2022. RESULTS: Intermittent fasting leads to weight loss of a similar magnitude to continuous energy restriction. Most of the evidence shows that intermittent fasting leads to greater fat loss as measured by fat mass (kg) or body fat percentage compared to an ad libitum diet, but fat loss attained during intermittent fasting is not significantly different to continuous energy restriction, although recent evidence shows intermittent fasting to be superior. There is mixed evidence for the impact of intermittent fasting on insulin resistance, fasting glucose and lipid profile. Some studies focused on populations of Muslim people, which showed that Ramadan fasting may lead to weight loss and improvement of metabolic parameters during fasting, although the effects are reversed when fasting is finished. CONCLUSIONS: Intermittent fasting is more effective than an ad libitum dietary intake, and equally or more effective as continuous energy restriction, for weight management. However, there is inconclusive evidence on whether intermittent fasting has a clinically beneficial effect on glucose and lipid metabolism.
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Jejum Intermitente , Obesidade , Humanos , Jejum , Redução de Peso , Glucose , Restrição CalóricaRESUMO
Novel gonadotrophin releasing hormone (GnRH) antagonist treatments have recently been developed in combination with hormonal add-back therapy, as an oral treatment option for women suffering from uterine fibroids. Registration trials assessing the GnRH antagonist combination preparations with relugolix, elagolix and linzagolix have assessed treatment efficacy for fibroid-related heavy menstrual blood loss in comparison to placebo. Marketing authorization has been granted by several agencies including those in Europe, the United Kingdom and the United States. While the registration trials report a robust effect on the reduction of heavy menstrual blood loss and improvement in quality of life scores, reticence is advised before widespread prescription. In this review, we demonstrate limitations in the trial data, namely a lack of generalizability due to the restricted study population, the lack of transparency in the distribution of disease-level characteristics limiting the predictability of treatment success in the real-world diverse population, and the absence of any comparison to current alternative treatment methods. Importantly, no clinically meaningful volume reductions were found with GnRH antagonist combination preparations, and long-term safety data, particularly concerning modest but stable bone mineral density decline, need further addressing. Symptoms related to uterine fibroids adversely affect many women's quality of life and effective medical treatments are lacking. However, despite the urgent need for conservative treatments, it is vitally important that novel drugs, like combination oral GnRH antagonists, undergo sufficiently rigorous evaluation of safety, effectiveness and cost-effectiveness in a representative population and are compared with alternative treatment methods before introduction into mainstream clinical practice.
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Leiomioma , Neoplasias Uterinas , Humanos , Feminino , Neoplasias Uterinas/tratamento farmacológico , Qualidade de Vida , Hormônio Liberador de Gonadotropina/uso terapêutico , Leiomioma/tratamento farmacológico , Resultado do TratamentoRESUMO
BACKGROUND: Psychological stress has an established bi-directional relationship with obesity. Mindfulness techniques reduce stress and improve eating behaviours, but their long-term impact remains untested. CALMPOD (Compassionate Approach to Living Mindfully for Prevention of Disease) is a psychoeducational mindfulness-based course evidenced to improve eating patterns across a 6-month period, possibly by reducing stress. However, no long-term evaluation of impact exists. AIMS: This study retrospectively evaluates 2-year outcomes of CALMPOD on patient engagement, weight and metabolic markers. METHOD: All adults with a body mass index >35 kg/m2 attending an UK obesity service during 2016-2020 were offered CALMPOD. Those who refused CALMPOD were offered standard lifestyle advice. Routine clinic data over 2 years, including age, gender, 6-monthly appointment attendance, weight, haemoglobin A1C and total cholesterol, were pooled and analysed to evaluate CALMPOD. RESULTS: Of 289 patients, 163 participated in the CALMPOD course and 126 did not. No baseline demographic differences existed between the participating and non-participating groups. The CALMPOD group had improved attendance across all 6-monthly appointments compared with the non-CALMPOD group (P < 0.05). Mean body weight reduction at 2 years was 5.6 kg (s.d. 11.2, P < 0.001) for the CALMPOD group compared with 3.9 kg (s.d. 10.5, P < 0.001) for the non-CALMPOD group. No differences in haemoglobin A1C and fasting serum total cholesterol were identified between the groups. CONCLUSIONS: The retrospective evaluation of CALMPOD suggests potential for mindfulness and compassion-based group educational techniques to improve longer-term patient and clinical outcomes. Prospective large-scale studies are needed to evaluate the impact of stress on obesity and the true impact of CALMPOD.
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Brassinosteroids (BRs) are required for various aspects of plant growth and development, but also participate in stress responses. The hormones convey their activity through transcriptional regulation and posttranslational modification of transcription factors and one class are basic helix-loop-helix (bHLH) proteins of the BR Enhanced Expression (BEE) subfamily, which in Arabidopsis thaliana include BEE1-3 and CESTA (CES). CES and the BEEs promote the expression of different BR-responsive genes, including genes encoding gibberellin (GA) biosynthetic and catabolizing enzymes, as well as cold-responsive genes. Interestingly, in terms of an application, CES could promote both fruit growth and cold stress tolerance when over-expressed in A. thaliana and here it was investigated, if this function is conserved in the fruit crop Solanum lycopersicum (cultivated tomato). Based on amino acid sequence similarity and the presence of regulatory motifs, a CES orthologue of S. lycopersicum, SlCES, was identified and the effects of its over-expression were analysed in tomato. This showed that SlCES, like AtCES, was re-localized to nuclear bodies in response to BR signaling activation and that it effected GA homeostasis, with related phenotypes, when over-expressed. In addition, over-expression lines showed an increased chilling tolerance and had altered fruit characteristics. The possibilities and potential limitations of a gain of SlCES function as a breeding strategy for tomato are discussed.
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OBJECTIVES: Transcervical resection of myoma (TCRM) is a widely implemented treatment for submucous fibroids. The aim of this study is to evaluate the effect of TCRM on menstrual bleeding, fibroid related symptoms and quality of life and hemoglobin (Hb) levels. STUDY DESIGN: A prospective cohort study was conducted in three teaching hospitals and two academic hospitals in the Netherlands. Patients with HMB (PBAC score > 150) and submucous fibroids (type 0, 1, 2, 3, 4 and hybrid type 2-5) scheduled for TCRM were eligible. At baseline and 3 months after TCRM a Trans Vaginal Ultrasound (TVU) was performed and a Hb sample was taken. Patients filled out the Pictorial Blood Assessment Chart (PBAC) and the Uterine Fibroid Symptom and Quality of Life (UFS-QOL) questionnaire at baseline and up to 6 months after surgery. Primary outcome was improvement in PBAC score 6 months after surgery. Secondary outcomes were improvement in PBAC score and Hb level 3 months after surgery and UFS-QOL scores 3 and 6 months after surgery. RESULTS: 126 patients were included and 104 were operated. PBAC were obtained from 98 patients. Six months after surgery, 56.6% of patients went from HMB to normal menstrual bleeding (PBAC < 150). A significant reduction in median PBAC scores of 427 (IQR 198 - 1392) (p <.0001) was found (86% improvement). UFS-QOL scores were obtained from 91 patients. Symptom severity improved from a median of 54 on a scale of 100 (IQR 44-66) at baseline to 22 (IQR 9-41) after 6 months (p <.0001) (59% improvement). Health related quality of life (HRQOL) improved from a median score of 44 on a scale of 100 (IQR 33-62) to 89 (IQR 67-97) 6 months after surgery (p <.0001) (102% improvement). CONCLUSION: TCRM significantly reduces the amount of menstrual bleeding, severity of fibroid related symptoms and improves HRQOL in patients with submucous fibroids.
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Leiomioma , Menorragia , Neoplasias Uterinas , Feminino , Hemorragia , Humanos , Leiomioma/complicações , Leiomioma/cirurgia , Menorragia/etiologia , Menorragia/cirurgia , Estudos Prospectivos , Qualidade de Vida , Neoplasias Uterinas/complicações , Neoplasias Uterinas/cirurgiaRESUMO
Ulipristal acetate (UPA) is a medical treatment for uterine fibroids and was authorized for surgical pre-treatment in 2012 after the conduct of the PEARL I and II randomized controlled trials and for intermittent treatment after the observational PEARL III and IV trials. However, UPA came into disrepute due to its temporary suspension in 2017 and 2020 because of an apparent association with liver injury. This clinical opinion paper aims to review the process of marketing authorization and implementation of UPA, in order to provide all involved stakeholders with recommendations for the introduction of future drugs. Before marketing authorization, the European Medicines Agency (EMA) states that Phase III registration trials should evaluate relevant outcomes in a representative population, while comparing to gold-standard treatment. This review shows that the representativeness of the study populations in all PEARL trials was limited, surgical outcomes were not evaluated and intermittent treatment was assessed without comparative groups. Implementation into clinical practice was extensive, with 900â000 prescribed treatment cycles in 5 years in Europe and Canada combined. Extremely high costs are involved in developing and evaluating pre-marketing studies in new drugs, influencing trial design and relevance of chosen outcomes, thereby impeding clinical applicability. It is vitally important that the marketing implementation after authorization is regulated in such way that necessary evidence is generated before widespread prescription of a new drug. All stakeholders, from pharmaceutical companies to authorizing bodies, governmental funding bodies and medical professionals should be aware of their role and take responsibility for their part in this process.
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Leiomioma , Norpregnadienos , Neoplasias Uterinas , Europa (Continente) , Feminino , Humanos , Leiomioma/complicações , Norpregnadienos/uso terapêutico , Neoplasias Uterinas/complicações , Neoplasias Uterinas/tratamento farmacológicoRESUMO
Brassinosteroids (BRs) are plant steroids that have growth-promoting capacities, which are partly enabled by an ability to induce biosynthesis of gibberellins (GAs), a second class of plant hormones. In addition, BRs can also activate GA catabolism; here we show that in Arabidopsis (Arabidopsis thaliana) the basic helix-loop-helix transcription factor CESTA (CES) and its homologues BRASSINOSTEROID-ENHANCED EXPRESSION (BEE) 1 and 3 contribute to this activity. CES and the BEEs are BR-regulated at the transcriptional and posttranslational level and participate in different physiological processes, including vegetative and reproduction development, shade avoidance, and cold stress responses. We show that CES/BEEs can induce the expression of the class III GA 2-oxidase GA2ox7 and that this activity is increased by BRs. In BR signaling - and CES/BEE-deficient mutants, GA2ox7 expression decreased, yielding reduced levels of GA110, a product of GA2ox7 activity. In plants that over-express CES, GA2ox7 expression is hyper-responsive to BR, GA110 levels are elevated and amounts of bioactive GA are reduced. We provide evidence that CES directly binds to the GA2ox7 promoter and is activated by BRs, but can also act by BR-independent means. Based on these results, we propose a model for CES activity in GA catabolism where CES can be recruited for GA2ox7 induction not only by BR, but also by other factors.
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Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Brassinosteroides/metabolismo , Regulação da Expressão Gênica de Plantas , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Reguladores de Crescimento de Plantas/metabolismoRESUMO
OBJECTIVE: Uterine fibroids can cause a variety of symptoms in women, from heavy menstrual bleeding and dysmenorrhea to bulk symptoms. The Uterine Fibroid Symptom and health-related Quality Of Life questionnaire (UFS-QOL) is a patient-reported outcome measure developed for assessing fibroid-related symptoms in a standardised way. Our aim was to translate and validate the UFS-QOL in Dutch. DESIGN: Validation study. SETTING: Patients were recruited by a gynaecologist at the outpatient clinic. PARTICIPANTS: Women with uterine fibroids. METHODS: The UFS-QOL was translated into Dutch (UFS-QOL NL) and validated through testing construct validity (comprising of structural validity and hypotheses testing), reliability, responsiveness and interpretability, assessing floor and ceiling effects and minimal important change. An option to answer 'not applicable' was added to the translated questionnaire. RESULTS: 191 women with uterine fibroids completed the UFS-QOL NL at baseline, after 2 weeks and after 3 months. The questionnaire retained the same factor structure after translation (Comparative Fit Index 0.94-0.95; Tucker-Lewis fit Index 0.93-0.95; Root Mean Square Error of Approximation 0.10-0.11) and correlations to other questionnaires (RAND 36, Hospital Anxiety and Depression Scale and Golombok Rust Inventory of Sexual Satisfaction) were generally moderate, as hypothesised (Pearson's r 0.3-0.7). We found a sufficient reliability with intraclass correlation coefficients of approximately 0.8-0.9 for all subscales. Responsiveness was sufficient when testing hypotheses comparing women who had surgery with those who did not. Cronbach's alpha was higher than 0.7 for all subscales, indicating sufficient internal consistency and there were no concerns about floor or ceiling effects. Minimal important change could not be calculated due to low correlation between the different subscales and the anchor question. CONCLUSIONS: The results support the measurement properties of the Dutch UFS-QOL for assessing fibroid-related symptoms and health-related quality of life in Dutch women with uterine fibroids.
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Leiomioma , Neoplasias Uterinas , Feminino , Humanos , Psicometria , Qualidade de Vida , Reprodutibilidade dos Testes , Inquéritos e QuestionáriosRESUMO
BACKGROUND: Obesity underlies much chronic disease. Digitalization of obesity management provides an opportunity to innovate our traditional model of health care delivery within this setting, and to transform its scalability potentially to the population level. OBJECTIVE: The objective was to assess the feasibility and effectiveness of the Low Carb Program app for weight loss, applied within our hospital-based (tier 3) obesity service. Due to the disrupting effects of the COVID-19 pandemic on our obesity service, we compared the clinical outcomes from the Low Carb Program app applied in the context of remote patient appointments over the telephone with the prepandemic traditional standard of care. METHODS: We invited patients who attended our hospital-based obesity service to engage with the Low Carb Program smartphone app. We combined this approach with remote delivery (over the telephone) of obesity management from medical and psychology members of our obesity team during the COVID-19 pandemic. Outcome variables included changes in body weight and changes in HbA1c as a marker of glycemic control. We compared data from the Low Carb Program group with a retrospective control group (n=126) that had received traditional face-to-face obesity management from our team without concomitant use of the Low Carb Program app in the pre-COVID-19 era. T test comparisons were employed, with P<.05 considered significant. RESULTS: The mean weight of participants (n=105) was 130.2 kg, with 59% (n=62) females and a mean age of 48.8 years. Most participants (90/105, 86%) completed the Low Carb Program app registration process and engaged with the Low Carb Program app program; at follow-up, most participants (88/105, 84%) had actively engaged with the Low Carb Program app within the prior 30 days. The majority of participants (58/105, 55%) self-reported outcomes within the app. Mean duration of clinical follow-up for recruited participants who received the app was 7.4 months. Paired data were available for 48 participants for body weight and 41 participants for HbA1c. Paired sample t test analysis revealed a statistically significant mean loss of body weight of 2.7 kg (P=.001) and improvement in HbA1c of 3.3 mmol/mol (P=.01). The mean weight of control group patients (n=126) was 137.1 kg, with 74% (93/126) females and a mean age of 44.4 years. The mean follow-up for this group was 6 months. Data comparisons between the app user group and the pre-COVID-19 retrospective control group revealed equivalence for loss of body weight and change in HbA1c between the two groups. CONCLUSIONS: We provide evidence to support the feasibility of implementing the Low Carb Program app combined with remote management; this is the first proof of concept for digitalized management within a hospital-based (tier 3) obesity service. We demonstrate the potential clinical efficacy of the approach in terms of improvements in body weight and glycemic control.
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BACKGROUND: In premenopausal women, treatment with direct oral factor Xa inhibitors is associated with an increased risk of heavy menstrual bleeding (HMB) compared with vitamin K antagonists (VKA). Treatment with the direct oral thrombin inhibitor dabigatran appears to be associated with a reduced risk of HMB compared with VKA. These findings come from small observational studies or post hoc analyses of trials in which HMB was not a primary outcome. Use of tranexamic acid during the menstrual period may be effective in patients with HMB, but prospective data regarding efficacy and safety in patients on anticoagulant treatment are lacking. RATIONALE AND DESIGN: A direct comparison of a factor Xa inhibitor and a thrombin inhibitor with HMB as primary outcome, as well as an evaluation of the effects of adding tranexamic acid in women with anticoagulant-associated HMB is highly relevant for clinical practice. The MEDEA study is a randomized, open-label, pragmatic clinical trial to evaluate management strategies in premenopausal women with HMB associated with factor Xa inhibitor therapy. OUTCOMES: Women using factor Xa inhibitors with proven HMB, as assessed by a pictorial blood loss assessment chart (PBAC) score of >150, will be randomized to one of three study arms: (i) switch to dabigatran; (ii) continue factor Xa inhibitor with addition of tranexamic acid during the menstrual period; or (iii) continue factor Xa inhibitor without intervention. The primary outcome is the difference in PBAC score before and after randomization. Here, we present the rationale and highlight several unique features in the design of the study.
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CONTEXT: Hypoparathyroidism is a rare disease and, as such, its natural history, long-term complications, and correct clinical management remain unclear. OBJECTIVE: To describe the natural history and clinical characteristics of the disease. DESIGN AND SETTING: To present a retrospective observational analysis from 7 specialized centers in Buenos Aires, Argentina. PATIENTS: Chronic hypoparathyroid patients followed-up between 1985 and December 2018. MAIN OUTCOME MEASURES: Data on demographics, etiology, clinical complications, biochemical parameters, dual-energy x-ray absorptiometry (DXA) values, and treatment doses were collected. RESULTS: A total of 322 subjects with chronic hypoparathyroidism were included; 85.7% were female, the mean age was 55.2â ±â 16.8 years, and the mean age at diagnosis was 43.8â ±â 16.8 years. Prevalence of surgical hypoparathyroidism was 90.7%, with the most common causes being thyroid carcinoma and benign thyroid disease. A history of hypocalcemia requiring hospitalization was present in 25.7% of the whole group and in 4.3% of patients who had a history of seizures. Overall, 40.9% of our patients had reported at least 1 neuromuscular symptom. Renal insufficiency was present in 22.4% of our patients and was significantly associated with age (Pâ <â 0.0001). Hyperphosphatemia was present in 42% of patients. A history of severe hypocalcemia, paresthesias, tetany, ganglia calcifications, seizures, and cataracts was significantly higher in nonsurgical patients. CONCLUSION: Although these patients were followed-up by experienced physicians, clinical management was heterogeneous and probably insufficient to assess all the potential complications of this chronic disease. Almost 70% of the study's group of patients met the experts' indications for considering the use of rhPTH 1-84. Being aware of this fact is the 1st step in improving our medical management of this disease in the future.
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BACKGROUND: Identifying and tracking somatic mutations in cell-free DNA (cfDNA) by next-generation sequencing (NGS) has the potential to transform the clinical management of subjects with advanced non-small cell lung cancer (NSCLC). METHODS: Baseline tumor tissue (n = 47) and longitudinal plasma (n = 445) were collected from 71 NSCLC subjects treated with chemotherapy. cfDNA was enriched using a targeted-capture NGS kit containing 197 genes. Clinical responses to treatment were determined using RECIST v1.1 and correlations between changes in plasma somatic variant allele frequencies and disease progression were assessed. RESULTS: Somatic variants were detected in 89.4% (42/47) of tissue and 91.5% (407/445) of plasma samples. The most commonly mutated genes in tissue were TP53 (42.6%), KRAS (25.5%), and KEAP1 (19.1%). In some subjects, the allele frequencies of mutations detected in plasma increased 3-5 months prior to disease progression. In other cases, the allele frequencies of detected mutations declined or decreased to undetectable levels, indicating clinical response. Subjects with circulating tumor DNA (ctDNA) levels above background had significantly shorter progression-free survival (median: 5.6 vs 8.9 months, respectively; log-rank p = 0.0183). CONCLUSION: Longitudinal monitoring of mutational changes in plasma has the potential to predict disease progression early. The presence of ctDNA mutations during first-line treatment is a risk factor for earlier disease progression in advanced NSCLC.
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Adenocarcinoma/sangue , Carcinoma Pulmonar de Células não Pequenas/sangue , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Neoplasias Pulmonares/sangue , Plasma/metabolismo , Adenocarcinoma/patologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Progressão da Doença , Feminino , Humanos , Estudos Longitudinais , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , MutaçãoRESUMO
Many developmental processes in plants are regulated by GA hormones. GA homeostasis is achieved via complex biosynthetic and catabolic pathways. GA catabolic enzymes include GA 2-oxidases that are classified into three classes. Members of class III GA 2-oxidases typically act on GA precursors containing a C20-skeleton. Here, we identified two further members of this class of GA 2-oxidases, namely AtGA2ox9 and AtGA2ox10, in the Arabidopsis (Arabidopsis thaliana) genome. Both genes encode enzymes that have functional similarities to AtGA2ox7 and AtGA2ox8, which are class III GA 2-oxidases that 2ß-hydroxylate C20-GAs. Previously unknown for GA 2-oxidases, AtGA2ox9 performs 2α-hydroxylation of C19-GAs and harbors putative desaturating activity of C20-GAs. Additionally, AtGA2ox9 and AtGA2ox10 exhibit GA 20-oxidase activity. AtGA2ox9 oxidizes carbon-20 to form tricarboxylic acid C20-GAs, whereas AtGA2ox10 produces C19-GA9 AtGA2ox9 transcript levels increase after cold treatment and AtGA2ox10 is expressed mainly in the siliques of Arabidopsis plants. Atga2ox9 loss-of-function mutants are more sensitive to freezing temperatures, whereas Atga2ox10 loss-of-function mutants produce considerably more seeds per silique than wild-type plants. We conclude that in Arabidopsis, AtGA2ox9 contributes to freezing tolerance and AtGA2ox10 regulates seed production.
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Arabidopsis/enzimologia , Arabidopsis/metabolismo , Oxigenases de Função Mista/metabolismo , Arabidopsis/genética , Flores/genética , Flores/metabolismo , Congelamento , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Giberelinas/metabolismo , Oxigenases de Função Mista/genéticaRESUMO
Bioactive gibberellins (GAs) are central regulators of plant growth and development, including seed development. GA homeostasis is achieved via complex biosynthetic and catabolic pathways, whose exact activities remain to be elucidated. Here, we isolated two cDNAs from mature or imbibed cucumber seeds with high sequence similarity to known GA 3-oxidases. We found that one enzyme (designated here CsGA3ox5) has GA 3-oxidation activity. However, the second enzyme (designated CsGA1ox/ds) performed multiple reactions, including 1ß-oxidation and 9,11-desaturation of GAs, but was lacking the 3-oxidation activity. CsGA1ox/ds overexpression in Arabidopsis plants resulted in severely dwarfed plants that could be rescued by the exogenous application of bioactive GA4, confirming that CsGA1ox/ds catabolizes GAs. Substitution of three amino acids in CsGA1ox/ds, Phe93, Pro106, and Ser202, with those typically conserved among GA 3-oxidases, Tyr93, Met106, and Thr202, respectively, conferred GA 3-oxidase activity to CsGA1ox/ds and thereby augmented its potential to form bioactive GAs in addition to catabolic products. Accordingly, overexpression of this amino acid-modified GA1ox/ds variant in Arabidopsis accelerated plant growth and development, indicating that this enzyme variant can produce bioactive GAs in planta Furthermore, a genetically modified GA3ox5 variant in which these three canonical GA 3-oxidase amino acids were changed to the ones present in CsGA1ox/ds was unable to convert GA9 to GA4, highlighting the importance of these three conserved amino acids for GA 3-oxidase activity.
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Oxigenases de Função Mista/metabolismo , Proteínas de Plantas/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Cucumis sativus/metabolismo , Giberelinas/metabolismo , Oxigenases de Função Mista/classificação , Oxigenases de Função Mista/genética , Mutagênese , Fenótipo , Filogenia , Proteínas de Plantas/classificação , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/metabolismoRESUMO
Gibberellin (GA) hormones regulate the development of plants and their responses to environmental signals. The final part of GA biosynthesis is catalyzed by multifunctional 2-oxoglutarate-dependent dioxygenases, which are encoded by multigene families. According to their enzymatic properties and physiological functions, GA-oxidases are classified as anabolic or catabolic enzymes. Together they allow complex regulation of the GA biosynthetic pathway, which adapts the specific hormonal needs of a plant during development and interaction with its environment. In this review, we combine recent advances in enzymatic characterization of the multifunctional GA-oxidases, in particular, from cucumber and Arabidopsis that have been most comprehensively investigated.
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Dioxigenases/metabolismo , Giberelinas/metabolismo , Reguladores de Crescimento de Plantas/biossíntese , Proteínas de Plantas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Plantas/enzimologia , Plantas/metabolismoRESUMO
Plants are able to sense a rise in temperature of several degrees, and appropriately adapt their metabolic and growth processes. To this end, plants produce various signalling molecules that act throughout the plant body. Here, we report that root-derived GA12, a precursor of the bioactive gibberellins, mediates thermo-responsive shoot growth in Arabidopsis. Our data suggest that root-to-shoot translocation of GA12 enables a flexible growth response to ambient temperature changes.