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1.
Rev. adm. pública (Online) ; 58(3): e20230255, 2024. tab, graf
Artigo em Inglês, Português | LILACS | ID: biblio-1565206

RESUMO

Abstract This study developed and tested the validity of a scale that measures skills for managing work from home, such as: informing change, searching for information, establishing priorities, setting and adapting goals, assessing work outputs, distributing tasks, and offering feedback. Participants were 2,038 managers from three Brazilian public organizations. Exploratory, confirmatory, and multigroup factor analyses revealed an 8-item unidimensional structure, excellent reliability indices, and goodness of fit, besides invariance for gender and age groups. The short scale permits testing research models with multiple variables, comparative (voluntary vs. compulsory telework), and cross-cultural studies.


Resumen Este estudio desarrolló y probó la validez de una escala que mide las habilidades para gestionar el trabajo desde casa, como: informar cambios, buscar información, establecer prioridades, establecer y adaptar metas, evaluar los resultados del trabajo, distribuir tareas y dar feedback. Participaron 2.038 directivos de tres organizaciones públicas brasileñas. Los análisis factoriales exploratorios, confirmatorios y multigrupo revelaron una estructura unifactorial de 8 ítems, excelentes índices de confiabilidad y bondad de ajuste, además de invariancia para género y rangos etarios. La escala corta permite probar modelos de investigación con múltiples variables, estudios comparativos (teletrabajo voluntario vs. obligatorio) e interculturales.


Resumo Este estudo desenvolveu e testou a validade de uma escala que mede as habilidades para gerir o trabalho desde casa, como: relatar mudanças, buscar informações, definir prioridades, definir e adaptar metas, avaliar os resultados do trabalho, distribuir tarefas e fornecer feedback. Participaram 2.038 gestores de três organizações públicas brasileiras. As análises fatoriais exploratórias, confirmatórias e multigrupo revelaram uma estrutura unifatorial de oito itens, excelentes índices de confiabilidade e qualidade de ajuste, bem como invariância para gênero e faixas etárias. A escala curta permite testar modelos de pesquisa com múltiplas variáveis, estudos comparativos (teletrabalho voluntário versus compulsório) e estudos interculturais.


Assuntos
Organização e Administração , Aptidão , Teletrabalho
2.
Microbiol Spectr ; : e0144123, 2023 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-37695041

RESUMO

Listeria monocytogenes is ubiquitously found in nature and can easily enter food-processing facilities due to contaminations of raw materials. Several countermeasures are used to combat contamination of food products, for instance, the use of disinfectants that contain quaternary ammonium compounds, such as benzalkonium chloride (BAC) and cetyltrimethylammonium bromide (CTAB). In this study, we assessed the potential of the commonly used wild-type strain EGD-e to adapt to BAC and CTAB under laboratory growth conditions. All BAC-tolerant suppressors exclusively carried mutations in fepR, encoding a TetR-like transcriptional regulator, or its promoter region, likely resulting in the overproduction of the efflux pump FepA. In contrast, CTAB tolerance was associated with mutations in sugR, which regulates the expression of the efflux pumps SugE1 and SugE2. L. monocytogenes strains lacking either FepA or SugE1/2 could still acquire tolerance toward BAC and CTAB. Genomic analysis revealed that the overproduction of the remaining efflux system could compensate for the deleted one, and even in the absence of both efflux systems, tolerant strains could be isolated, which all carried mutations in the diacylglycerol kinase-encoding gene lmo1753 (dgkB). DgkB converts diacylglycerol to phosphatidic acid, which is subsequently reused for the synthesis of phospholipids, suggesting that alterations in membrane composition could be the third adaptation mechanism. IMPORTANCE Survival and proliferation of Listeria monocytogenes in the food industry are ongoing concerns, and while there are various countermeasures to combat contamination of food products, the pathogen still successfully manages to withstand the harsh conditions present in food-processing facilities, resulting in reoccurring outbreaks, subsequent infection, and disease. To counteract the spread of L. monocytogenes, it is crucial to understand and elucidate the underlying mechanism that permits their successful evasion. We present various adaptation mechanisms of L. monocytogenes to withstand two important quaternary ammonium compounds.

3.
Rev. psicol. organ. trab ; 21(3): 1655-1664, jul.-set. 2021. ilus
Artigo em Português | LILACS-Express | LILACS, INDEXPSI | ID: biblio-1347802

RESUMO

Muitos trabalhadores migraram para o teletrabalho durante a pandemia de COVID-19. A realização das tarefas integralmente em casa trouxe desafios, principalmente àqueles que não possuíam experiência anterior com a modalidade, como a conciliação trabalho-família e o uso de tecnologias digitais. Este estudo relata o desenvolvimento e as evidências de validade psicométrica da Escala de Habilidades para o Teletrabalho em Casa (EHTC). A pesquisa foi aplicada a 7.608 servidores de diferentes órgãos públicos brasileiros. Realizaram-se análises estatísticas descritivas, fatoriais exploratórias e confirmatórias e de confiabilidade. O instrumento possui uma estrutura empírica bifatorial que avalia habilidades para o balanceamento entre trabalho e outras atividades (soft skills) e para utilização de recursos digitais nas interações de trabalho (hard skills). A EHTC pode ser usada para identificar a adaptação e o preparo para o teletrabalho em casa e investigar associações entre essas habilidades e outros indicadores.


Many workers migrated to teleworking during the COVID-19 pandemic. Performing work tasks entirely at home brought challenges, especially for those who had no previous experience with the modality, such as work-family conciliation and the use of digital technologies. This study reports the development and evidence of psychometric validity of the Skills for Working from Home scale (SWHS). The survey was applied to 7,608 government employees from Brazilian public agencies. Descriptive statistical analyses, and exploratory, confirmatory, and reliability factor analyses were performed. The instrument has a bifactorial empirical structure that assesses skills for balancing work and other activities (soft skills) and skills for using digital communication resources in work interactions (hard skills). The SWHS can be used to identify the adaptation and preparation for working from home, as well as to investigate possible associations between these skills and other indicators.


Muchos trabajadores migraron para el teletrabajo durante la pandemia de COVID-19. Realizar las tareas íntegralmente en casa trajo desafíos, especialmente para quienes no tenían experiencia previa con la modalidad, como la conciliación trabajo-familia y el uso de tecnologías digitales. Este estudio reporta el desarrollo y las evidencias de validad psicométrica de la Escala de Habilidades para el Teletrabajo en Casa (EHTC). La investigación se aplicó a 7.608 funcionarios de organos públicos brasileños. Se realizaron análisis estadísticos descriptivos, factoriales exploratorios, confirmatorios y de confiabilidad. El instrumento posee una estructura empírica bifactorial que evalúa habilidades para equilibrar el trabajo y otras actividades (soft skills) y para el uso de recursos digitales en las interacciones laborales (hard skills). La EHTC puede ser utilizada para identificar la adaptación y preparación para el teletrabajo en casa e investigar posibles asociaciones entre estas habilidades y otros indicadores.

4.
Rev. psicol. organ. trab ; 19(4): 772-780, out.-dez. 2019. tab
Artigo em Português | LILACS | ID: biblio-1043295

RESUMO

Apesar da crescente adoção do teletrabalho no Brasil, há poucas publicações nacionais acerca dessa modalidade. Esta pesquisa tem como objetivos comparar as opiniões de 270 teletrabalhadores e 266 trabalhadores presenciais em relação ao desenho do trabalho, de acordo com a teoria de Morgeson e Humphrey (2006), e analisar a influência exercida por variáveis sociodemográficas e funcionais sobre características da tarefa e do conhecimento. Os dados foram submetidos a análises fatoriais, testes t e regressões múltiplas. Os principais resultados deste estudo mostraram que as percepções de teletrabalhadores e trabalhadores presenciais diferem em sete das dez características estudadas. Teletrabalhadores perceberam menor autonomia de decisão, variedade, significado, identificação da tarefa, complexidade, solução de problemas e especialização do que os trabalhadores presenciais. São necessários estudos que investiguem antecedentes da escolha da modalidade de trabalho pelo trabalhador e consequências do teletrabalho na motivação, no comprometimento, na saúde, na produtividade e nas interfaces entre o trabalho e a família.


Despite the increasing adoption of telework in Brazil, there are few national publications about this modality. This research aims to compare the views of 270 teleworkers and 266 face-to-face workers in relation to the design of the work, according to the Morgeson and Humphrey (2006) theory, and to analyze the influence exerted by sociodemographic and functional variables on task and knowledge characteristics. Data were submitted to factor analysis, t-tests, and multiple regressions. The main results of this study showed that the perceptions of teleworkers and face-to-face workers differ in seven of the ten characteristics studied. Teleworkers perceived less decision-making autonomy, task variety, task significance, task identity, job complexity, problem solving, and specialization than the face-to-face workers. Studies are required that investigate the antecedents of the choice of the modality and the consequences of telework on motivation, commitment, health, productivity, and interfaces between work and family.


A pesar de la creciente adopción del teletrabajo en Brasil, hay pocas publicaciones nacionales acerca de esa modalidad. Esta investigación tiene como objetivos comparar las opiniones de 270 teletrabajadores y 266 trabajadores presenciales con relación al diseño del trabajo, de acuerdo con la teoría de Morgeson y Humphrey (2006), y analizar la influencia ejercida por variables sociodemográficas y funcionales sobre características de la tarea y del conocimiento. Los datos fueron sometidos a análisis factoriales, pruebas t y regresiones múltiples. Los principales resultados mostraron que las percepciones de teletrabajadores y trabajadores presenciales difieren en siete de las diez características estudiadas. Los teletrabajadores percibieron menor autonomía de decisión, variedad, significado, identificación de la tarea, complejidad, solución de problemas y especialización que los trabajadores presenciales. Se necesitan estudios que investiguen antecedentes de la elección de la modalidad y consecuentes del teletrabajo sobre motivación, compromiso, salud, productividad e interfaces trabajo-familia.

5.
J Glob Oncol ; 4: 1-9, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30241256

RESUMO

Accessibility to immunohistochemistry (IHC) is invaluable to proper diagnosis and treatment of pediatric patients with malignant neoplasms. Whereas IHC is widely available in anatomic pathology laboratories in high-income countries, access to it in anatomic pathology laboratories of low- and middle-income countries remains a struggle, with many limitations. To advance the quality of the pathology service offered to children with cancer in areas with limited resources, a 5-day pathology training workshop was offered to pathologists and histotechnologists from various countries of the Central American and Caribbean region. An initial assessment of the workshop participants' current laboratory capacities was performed, and a regional training center was selected. Didactic and hands-on activities were offered, and review and evaluation of the IHC slides produced during the training course were compared with original slides from the participants' sites. This model of intensive 5-day training appears to be effective and can potentially be used in other budget-constrained regions. Moreover, it can serve as a continuing education activity for pathologists and histotechnologists, and as part of validations and quality improvement projects to build capacity and develop IHC assay proficiency in low- and middle-income countries.


Assuntos
Imuno-Histoquímica , Neoplasias/diagnóstico , Neoplasias/epidemiologia , Assistência ao Paciente , Região do Caribe/epidemiologia , América Central/epidemiologia , Criança , Gerenciamento Clínico , Humanos , Imuno-Histoquímica/métodos , Imuno-Histoquímica/normas , Gradação de Tumores , Estadiamento de Neoplasias , Neoplasias/terapia
6.
Molecules ; 22(3)2017 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-28273859

RESUMO

Pentacyclic triterpenes are naturally found in a great variety of fruits, vegetables and medicinal plants and are therefore part of the human diet. The beneficial health effects of edible and medicinal plants have partly been associated with their triterpene content, but the in vivo efficacy in humans depends on many factors, including absorption and metabolism. This review presents an overview of in vitro and in vivo studies that were carried out to determine the bioavailability of pentacyclic triterpenes and highlights the efforts that have been performed to improve the dissolution properties and absorption of these compounds. As plant matrices play a critical role in triterpene bioaccessibility, this review covers literature data on the bioavailability of pentacyclic triterpenes ingested either from foods and medicinal plants or in their free form.


Assuntos
Triterpenos Pentacíclicos/farmacocinética , Animais , Disponibilidade Biológica , Análise de Alimentos , Humanos , Técnicas In Vitro , Estrutura Molecular , Extratos Vegetais/farmacocinética , Plantas Medicinais/química
7.
Biopreserv Biobank ; 13(6): 421-9, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26697911

RESUMO

BACKGROUND: Biospecimens are essential resources for advancing basic and translational research. However, there are little data available regarding the costs associated with operating a biobank, and few resources to enable their long-term sustainability. To support the research community in this effort, the National Institutes of Health, National Cancer Institute's Biorepositories and Biospecimen Research Branch has developed the Biobank Economic Modeling Tool (BEMT). The tool is accessible at http://biospecimens.cancer.gov/resources/bemt.asp. METHODS: To obtain market-based cost information and to inform the development of the tool, a survey was designed and sent to 423 biobank managers and directors across the world. The survey contained questions regarding infrastructure investments, salary costs, funding options, types of biospecimen resources and services offered, as well as biospecimen pricing and service-related costs. RESULTS: A total of 106 responses were received. The data were anonymized, aggregated, and used to create a comprehensive database of cost and pricing information that was integrated into the web-based tool, the BEMT. The BEMT was built to allow the user to input cost and pricing data through a seven-step process to build a cost profile for their biobank, define direct and indirect costs, determine cost recovery fees, perform financial forecasting, and query the anonymized survey data from comparable biobanks. CONCLUSION: A survey was conducted to obtain a greater understanding of the costs involved in operating a biobank. The anonymized survey data was then used to develop the BEMT, a cost modeling tool for biobanks. Users of the tool will be able to create a cost profile for their biobanks' specimens, products and services, establish pricing, and allocate costs for biospecimens based on percent cost recovered, and perform project-specific cost analyses and financial forecasting.


Assuntos
Bancos de Espécimes Biológicos/economia , Bancos de Espécimes Biológicos/organização & administração , Administração Financeira , Modelos Econômicos , Academias e Institutos/economia , Análise Custo-Benefício , Custos e Análise de Custo , Bases de Dados Factuais , Internet , National Cancer Institute (U.S.) , Software , Inquéritos e Questionários , Pesquisa Translacional Biomédica , Estados Unidos
8.
Food Funct ; 4(11): 1595-601, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24056541

RESUMO

The composition of potatoes as determined by chemical extraction has been described extensively. It is thus quite well known that, among other compounds, potato is rich in polyphenols, vitamins and in some minerals. This paper underlines the important role of simulated gastro-intestinal in vitro digestion in the bioaccessibility of polyphenols (chlorogenic acid and derivatives, and rutin) from potatoes and sweet potatoes and their impact on iron uptake. Concentrations of polyphenols in the flesh of two potato cultivars (Nicola, white potato, and Vitelotte, purple potato) and sweet potato were measured by Ultra Performance Liquid Chromatography after boiling and after in vitro digestion. Chemical extraction underestimates polyphenol amounts that can be released during digestion and that are actually bioaccessible. Iron uptake, as evaluated by a ferritin assay, by intestinal human cells was decreased after incubation with the intestinal phase of in vitro digestion, presumably due to the presence of polyphenols.


Assuntos
Digestão , Mucosa Intestinal/metabolismo , Ipomoea batatas/metabolismo , Ferro/metabolismo , Extratos Vegetais/metabolismo , Polifenóis/metabolismo , Solanum tuberosum/metabolismo , Absorção , Linhagem Celular , Humanos , Ipomoea batatas/química , Modelos Biológicos , Extratos Vegetais/análise , Polifenóis/análise , Solanum tuberosum/química
9.
Biopreserv Biobank ; 11(2): 115-21, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24845432

RESUMO

BACKGROUND: Preservation and optimization of biosample integrity to foster relevant research results and outcomes is a guiding principle of sample management. Tracking pre-analytical biospecimen lifecycle variables and bioprocessing chain of custody data enables documentation of adherence to best, regulatory and quality biobanking practices. Knowledge of individual sample and sample set temperature variability is believed to enhance delineation of artifacts during downstream analysis. Analysis of temperature responses may elucidate understanding of temperature trends which can aid downstream interpretation and provide an empirical foundation for "fit for purpose" sample management protocols and evidence-based biobanking practices. Bluechiip and the American Type Culture Collection (ATCC) conducted a pilot to test the bluechiip technology(®) performance and validate key proofs of concept for tracking temperature of biological samples. METHODS: One hundred six (106) Corning(®) cryovials with bluechiip(®) buttons and one hundred six (106) standard Corning(®) cryovials labeled with 1-dimensional (1D) barcoded labels were evaluated. Identifiers were tracked and temperature data recorded in corresponding environments ranging from -192°C to +57°. RESULTS: Nine of ten proof of concepts, defined in collaboration with ATCC successfully demonstrated functional capabilities of the bluechiip(®) technology. Bar-code label read performance was compared, producing evidence demonstrating a high rate of failure on the bar-code arm. CONCLUSION: Temperature data collected heightened observations of sample temperature variability. Prevalence of bar-code label read failure and issues affecting reliability of barcode performance may be under-reported and unrecognized in sample management practice, particularly when the temperatures are lower than -60°C. It appears the bluechiip(®) tracking technology may offer increased reliability over one-dimensional (1D) bar-coding technology; however while promising these findings require validation in future trials, including two-dimensional (2D) bar-coding technologies.


Assuntos
Bancos de Espécimes Biológicos , Criopreservação/métodos , Temperatura , Humanos , Projetos Piloto , Reprodutibilidade dos Testes
11.
Biochem Biophys Res Commun ; 396(3): 656-61, 2010 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-20438708

RESUMO

AMP-activated protein kinase (AMPK), a known regulator of cellular and systemic energy balance, is now recognized to control cell division, cell polarity and cell migration, all of which depend on the actin cytoskeleton. Here we report the effects of A769662, a pharmacological activator of AMPK, on cytoskeletal organization and signalling in epithelial Madin-Darby canine kidney (MDCK) cells. We show that AMPK activation induced shortening or radiation of stress fibers, uncoupling from paxillin and predominance of cortical F-actin. In parallel, Rho-kinase downstream targets, namely myosin regulatory light chain and cofilin, were phosphorylated. These effects resembled the morphological changes in MDCK cells exposed to hyperosmotic shock, which led to Ca(2+)-dependent AMPK activation via calmodulin-dependent protein kinase kinase-beta(CaMKKbeta), a known upstream kinase of AMPK. Indeed, hypertonicity-induced AMPK activation was markedly reduced by the STO-609 CaMKKbeta inhibitor, as was the increase in MLC and cofilin phosphorylation. We suggest that AMPK links osmotic stress to the reorganization of the actin cytoskeleton.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Actinas/metabolismo , Citoesqueleto/metabolismo , Células Epiteliais/metabolismo , Fatores de Despolimerização de Actina/metabolismo , Actinas/ultraestrutura , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacologia , Animais , Benzimidazóis/farmacologia , Compostos de Bifenilo , Quinase da Proteína Quinase Dependente de Cálcio-Calmodulina/antagonistas & inibidores , Quinase da Proteína Quinase Dependente de Cálcio-Calmodulina/metabolismo , Linhagem Celular , Citoesqueleto/ultraestrutura , Cães , Células Epiteliais/ultraestrutura , Naftalimidas/farmacologia , Pressão Osmótica , Paxilina/metabolismo , Fosforilação , Pironas/farmacologia , Ribonucleotídeos/farmacologia , Solução Salina Hipertônica/farmacologia , Tiofenos/farmacologia , Quinases Associadas a rho/metabolismo
12.
J Physiol ; 588(Pt 13): 2315-28, 2010 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-20442269

RESUMO

This study was undertaken to investigate whether the mechanism of increased Na(+)-K(+)-2Cl(-) (NKCC1) cotransporter activity by osmotic shrinkage involved AMP-activated protein kinase (AMPK) activation. AMPK was found to phosphorylate a recombinant GST-dogfish (1-260) NKCC1 fragment at Ser38 and Ser214, corresponding to Ser77 and Ser242 in human NKCC1, respectively. Incubation of human erythrocytes with 20 microM A769662 AMPK activator increased Ser242 NKCC1 phosphorylation but did not stimulate (86)Rb(+) uptake. Under hypertonic conditions in human red blood cells (RBCs) incubated with 0.3 M sucrose, NKCC1 activity increased as measured by bumetanide-sensitive (86)Rb(+) uptake and AMPK was activated. However, there was no effect of AMPKalpha1 deletion in mouse RBCs on the increased rate of (86)Rb(+) uptake induced by hyperosmolarity. AMPK activation by osmotic shrinkage of mouse RBCs was abrogated by 10 microM STO-609 CaMKKbeta inhibitor, but incubation with STO-609 did not affect the increase in (86)Rb(+) uptake induced by hyperosmolarity. Osmotic shrinkage of human and mouse RBCs led to activation loop phosphorylation of the STE20/SPS1-related proline/alanine-rich kinase (SPAK) at Thr233, which was accompanied by phosphorylation of NKCC1 at Thr203/207/212, one of which (Thr207) is responsible for cotransporter activation. Therefore, phosphorylation-induced activation of NKCC1 by osmotic shrinkage does not involve AMPK and is likely to be due to SPAK activation.


Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Eritrócitos/metabolismo , Proteínas Serina-Treonina Quinases/fisiologia , Simportadores de Cloreto de Sódio-Potássio/sangue , Sequência de Aminoácidos , Animais , Compostos de Bifenilo , Western Blotting , Bumetanida/farmacologia , Diuréticos/farmacologia , Ativação Enzimática/fisiologia , Eritrócitos/ultraestrutura , Humanos , Técnicas In Vitro , Masculino , Espectrometria de Massas , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Confocal , Dados de Sequência Molecular , Pressão Osmótica , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Pironas/farmacologia , Rubídio/metabolismo , Simportadores de Cloreto de Sódio-Potássio/genética , Simportadores de Cloreto de Sódio-Potássio/fisiologia , Membro 2 da Família 12 de Carreador de Soluto , Tiofenos/farmacologia
14.
Pflugers Arch ; 455(6): 1129-40, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17957382

RESUMO

In rat epitrochlearis skeletal muscle, contraction inhibited the basal and insulin-stimulated rates of protein synthesis by 75 and 70%, respectively, while increasing adenosine monophosphate-activated protein kinase (AMPK) activity. Insulin, on the other hand, stimulated protein synthesis (by 30%) and increased p70 ribosomal protein S6 kinase (p70S6K) Thr389, 40S ribosomal protein S6 (rpS6) Ser235/236, rpS6 Ser240/244 and eukaryotic initiation factor-4E-binding protein-1 (4E-BP1) Thr37/46 phosphorylation over basal values. Electrical stimulation had no effect on mammalian target of rapamycin complex 1 (mTORC1) signalling, as reflected by the lack of reduction in basal levels of p70S6K, rpS6 Ser235/236, rpS6 Ser240/244 and 4E-BP1 phosphorylation, but did antagonize mTORC1 signalling after stimulation of the pathway by insulin. Eukaryotic elongation factor-2 (eEF2) Thr56 phosphorylation increased rapidly on electrical stimulation reaching a maximum at 1 min, whereas AMPK Thr172 phosphorylation slowly increased to reach threefold after 30 min. Eukaryotic elongation factor-2 kinase (eEF2K) was not activated after 30 min of contraction when AMPK was activated. This could not be explained by the expression of a tissue-specific isoform of eEF2K in skeletal muscle lacking the Ser398 AMPK phosphorylation site. Therefore, in this skeletal muscle system, the contraction-induced inhibition of protein synthesis could not be attributed to a reduction in mTORC1 signalling but could be due to an increase in eEF2 phosphorylation independent of AMPK activation.


Assuntos
Fatores de Iniciação em Eucariotos/fisiologia , Hipoglicemiantes/farmacologia , Insulina/farmacologia , Complexos Multienzimáticos/fisiologia , Contração Muscular/fisiologia , Proteínas Musculares/biossíntese , Músculo Esquelético/fisiologia , Proteínas Serina-Treonina Quinases/fisiologia , Proteínas Quinases Ativadas por AMP , Animais , Western Blotting , Estimulação Elétrica , Éxons/genética , Masculino , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Fosforilação , Biossíntese de Proteínas/fisiologia , RNA/biossíntese , RNA/genética , Ratos , Ratos Wistar , Receptor Cross-Talk/efeitos dos fármacos , Receptor Cross-Talk/fisiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Fatores de Transcrição/fisiologia
15.
Biochem Biophys Res Commun ; 345(4): 1414-24, 2006 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-16729974

RESUMO

Adiponectin (ApN) is an adipokine whose expression and plasma levels are inversely related to obesity and insulin-resistant states. The in vivo effects of a chronic expression of exogenous ApN restricted to adipose tissue are unclear. Moreover, the regulatory effects of ApN on its own expression and on that of its receptors are still unknown. In this study, we generated transgenic (Tg) mice with moderate expression of exogenous ApN targeted to adipose tissue (native full-length ApN being placed under control of the adipocyte promoter aP2). After a transient overexpression of ApN in young pups, we intriguingly observed a reduction of ApN mRNA levels and protein content in fat depots, together with a decrease of circulating ApN in adult mice. As a result, the phenotype of these adult mice included glucose intolerance, insulin resistance, and increased adiposity. Reduced expression of ApN in fat tissue was associated with diminished expression of uncoupling protein 2 involved in energy dissipation, and higher expression of fatty acid synthase, a key enzyme of lipogenesis, and of TNFalpha implicated in insulin resistance. Concomitantly, the expression of the ApN receptor AdipoR2 that mediates action of full-length ApN was downregulated, while that of AdipoR1 was unaffected. In agreement with the in vivo studies, recombinant ApN added to the culture medium of 3T3-F442A adipocytes caused a decrease in AdipoR2 and ApN mRNA levels. This treatment did not affect the expression of AdipoR1. Eventually, we demonstrated a contrario that AdipoR2 (but not R1) was specifically upregulated in fat of ApN(-/-) mice. Our in vivo and in vitro data provide evidence for a novel regulatory feedback loop by which ApN downregulates its own production and the expression of its AdipoR2 receptor.


Assuntos
Adiponectina/genética , Receptores de Superfície Celular/genética , Células 3T3 , Proteínas Quinases Ativadas por AMP , Adipócitos/citologia , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Adiponectina/sangue , Adiponectina/farmacologia , Tecido Adiposo/metabolismo , Animais , Glicemia/análise , Northern Blotting , Linhagem Celular , Regulação para Baixo/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/farmacocinética , Teste de Tolerância a Glucose , Humanos , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Complexos Multienzimáticos/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Adiponectina , Proteínas Recombinantes/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Tempo
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