132 resultados para GLUCAGON-LIKE PEPTIDE-1


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Background: Several plasma membrane transporters have been shown to mediate the cellular influx and/or efflux of iodothyronines, including the sodium-independent organic anion co-transporting polypeptide 1 (OATP1), the sodium taurocholate co-transporting polypeptide (NTCP), the L-type amino acid transporter 1 (LAT1) and 2 (LAT2), and the monocarboxylate transporter 8 (MCT8). The aim of this study was to investigate if the mRNAs of these transporters were expressed and regulated by thyroid hormone (TH) in mouse calvaria-derived osteoblastic MC3T3-E1 cells and in the fetal and postnatal bones of mice. Methods: The mRNA expression of the iodothyronine transporters was investigated with real-time polymerase chain reaction analysis in euthyroid and hypothyroid fetuses and litters of mice and in MC3T3-E1 cells treated with increasing doses of triiodothyronine (T(3); 10(-10) to 10(-6) M) or with 10(-8) M T(3) for 1-9 days. Results: MCT8, LAT1, and LAT2 mRNAs were detected in fetal and postnatal femurs and in MC3T3-E1 cells, while OATP1 and NTCP mRNAs were not. LAT1 and LAT2 mRNAs were not affected by TH status in vivo or in vitro or by the stage of bone development or osteoblast maturation (analyzed by the expression of osteocalcin and alkaline phosphatase, which are key markers of osteoblastic differentiation). In contrast, the femoral mRNA expression of MCT8 decreased significantly during post-natal development, whereas MCT8 mRNA expression increased as MC3T3-E1 cells differentiated. We also showed that MCT8 mRNA was up-regulated in the femur of hypothyroid animals, and that it was down-regulated by treatment with T(3) in MC3T3-E1 cells. Conclusions: This is the first study to demonstrate the mRNA expression of LAT1, LAT2, and MCT8 in the bone tissue of mice and in osteoblast-like cells. In addition, the pattern of MCT8 expression observed in vivo and in vitro suggests that MCT8 may be important to modulate TH effects on osteoblast differentiation and on bone development and metabolism.

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Mariner-like elements are widely present in diverse organisms. These elements constitute a large fraction of the eukaryotic genome; they transpose by a ""cut-and-paste"" mechanism with their own transposase protein. We found two groups of mobile elements in the genus Rhynchosciara. PCR using primers designed from R. americana transposons (Ramar1 and Ramar2) were the starting point for this comparative study. Genomic DNA templates of four species: R. hollaenderi, R. millerii, R. baschanti, and Rhynchosciara sp were used and genomic sequences were amplified, sequenced and the molecular structures of the elements characterized as being putative mariner-like elements. The first group included the putative full-length elements. The second group was composed of defective mariner elements that contain a deletion overlapping most of the internal region of the transposase open reading frame. They were named Rmar1 (type 1) and Rmar2 (type 2), respectively. Many conserved amino acid blocks were identified, as well as a specific D,D(34) D signature motif that was defective in some elements. Based on predicted transposase sequences, these elements encode truncated proteins and are phylogenetically very close to mariner-like elements of the mauritiana subfamily. The inverted terminal repeat sequences that flanked the mariner-like elements are responsible for their mobility. These inverted terminal repeat sequences were identified by inverse PCR.

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We present Monte Carlo simulations for a molecular motor system found in virtually all eukaryotic cells, the acto-myosin motor system, composed of a group of organic macromolecules. Cell motors were mapped to an Ising-like model, where the interaction field is transmitted through a tropomyosin polymer chain. The presence of Ca(2+) induces tropomyosin to block or unblock binding sites of the myosin motor leading to its activation or deactivation. We used the Metropolis algorithm to find the transient and the equilibrium states of the acto-myosin system composed of solvent, actin, tropomyosin, troponin, Ca(2+), and myosin-S1 at a given temperature, including the spatial configuration of tropomyosin on the actin filament surface. Our model describes the short- and long-range cooperativity during actin-myosin binding which emerges from the bending stiffness of the tropomyosin complex. We found all transition rates between the states only using the interaction energy of the constituents. The agreement between our model and experimental data also supports the recent theory of flexible tropomyosin.

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Three new bimetallic oxamato-based magnets with the proligand 4,5-dimethyl-1,2-phenylenebis-(oxamato) (dmopba) were synthesized using water or dimethylsulfoxide (DMSO) as solvents. Single crystal X-ray diffraction provided structures for two of them: [MnCu(dmopba)(H(2)O)(3)]n center dot 4nH(2)O (1) and [MnCu(dmopba)(DMSO)(3)](n center dot)nDMSO (2). The crystalline structures for both 1 and 2 consist of linearly ordered oxamato-bridged Mn(II)Cu(II) bimetallic chains. The magnetic characterization revealed a typical behaviour of ferrimagnetic chains for 1 and 2. Least-squares fits of the experimental magnetic data performed in the 300-20 K temperature range led to J(MnCu) = -27.9 cm(-1), g(Cu) = 2.09 and g(Mn) = 1.98 for 1 and J(MnCu) = -30.5 cm(-1), g(Cu) = 2.09 and g(Mn) = 2.02 for 2 (H = -J(MnCu)Sigma S(Mn, i)(S(Cu, i) + S(Cu, i-1))). The two-dimensional ferrimagnetic system [Me(4)N](2n){Co(2)[Cu(dmopba)](3)}center dot 4nDMSO center dot nH(2)O (3) was prepared by reaction of Co(II) ions and an excess of [Cu(dmopba)](2-) in DMSO. The study of the temperature dependence of the magnetic susceptibility as well as the temperature and field dependences of the magnetization revealed a cluster glass-like behaviour for 3.

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This paper presents a description of nuclear magnetic resonance (NMR) of quadrupolar systems using the Holstein-Primakoff (HP) formalism and its analogy with a Bose-Einstein condensate (BEC) system. Two nuclear spin systems constituted of quadrupolar nuclei I=3/2 ((23)Na) and I=7/2 ((133)Cs) in lyotropic liquid crystals were used for experimental demonstrations. Specifically, we derived the conditions necessary for accomplishing the analogy, executed the proper experiments, and compared with quantum mechanical prediction for a Bose system. The NMR description in the HP representation could be applied in the future as a workbench for BEC-like systems, where the statistical properties may be obtained using the intermediate statistic, first established by Gentile. The description can be applied for any quadrupolar systems, including new developed solid-state NMR GaAS nanodevices.

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We describe the effect of influenza-like illness (ILI) during the outbreak of pandemic (H1N1) 2009 on health care worker (HCW) absenteeism and compare the effectiveness and cost of 2 sick leave policies for HCWs with suspected influenza. We assessed initial 2-day sick leaves plus reassessment until the HOW was asymptomatic (2-day + reassessment policy), and initial 7-day sick leaves (7-day policy). Sick leaves peaked in August 2009: 3% of the workforce received leave for ILI. Costs during May October reached R$798,051.87 (approximate to US $443,362). The 7-day policy led to a higher monthly rate of sick leave days per 100 HCWs than did the 2-day + reassessment policy (8.72 vs. 3.47 days/100 HCWs; p<0.0001) and resulted in higher costs (US $609 vs. US $1,128 per HCW on leave). ILI affected HCW absenteeism. The 7-day policy was more costly and not more effective in preventing transmission to patients than the 2-day + reassessment policy.

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This work proposes an association between musical analysis techniques developed during the twentieth and the twenty-first centuries, presented by authors like Felix Salzer and Joseph Straus, and the musical theory concepts presented by Olivier Messiaen, for the analysis of Prelude n(o) 1, La Colombe. The analysis contributes to broaden the theory concepts presented by the composer. In the Conclusion we trace lines of an authorial sonority by Olivier Messiaen.

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Few studies have prospectively addressed the effects of exercise in the inflammatory activity of patients with coronary artery disease (CAD). We sought to evaluate the consequences of an acute bout of exercise on inflammatory markers and BNP in untrained CAD patients before and after randomization to a training program. 34 CAD patients underwent a 50-min acute exercise session on a cycle-ergometer at 65% peak oxygen uptake before and after blood sampling. They were then randomized to a 4-month chronic exercise program (15 patients) or general lifestyle recommendations (19 patients), undergoing a new acute session of exercise after that. In the overall population, acute exercise caused a significant increase in C-reactive protein [CRP; 1.79 (4.49) vs. 1.94 (4.89) mg/L, P < 0.001], monokine induced by interferon-gamma [Mig; 351 (324) vs. 373 (330) pg/mL, P = 0.027] and vascular adhesion molecule-1 [VCAM-1; 226 (82) vs. 252 (110) pg/mL, P = 0.02]. After 4-months, in exercise-trained patients, there was a significant decrease in the inflammatory response provoked by the acute exercise compared to patients in the control group reflected by a significant decrease in the differences between rest and post-exercise levels of CRP [-0.29 (0.84) mg/L vs. -0.11 (0.21) mg/L, P = 0.05]. Resting BNP was also significantly lower in exercise-trained patients when compared to untrained controls [15.6 (16.2) vs. 9.7 (11.4) pg/mL, P = 0.04 and 19.2 (27.8) vs. 23.2 (27.5) pg/mL, P = 0.76; respectively]. Chronic exercise training might partially reverse the inflammatory response caused by acute exercise in CAD patients. These results suggest that regular exercise is an important nonpharmacological strategy to the improvement in inflammation in CAD patients.

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Ticks (Acari: Ixodidae) are bloodsucking ectoparasitic arthropods of human and veterinary medical importance. Tick saliva has been shown to contain a wide range of bioactive molecules with vasodilatory, antihemostatic, and immunomodulatory activities. We have previously demonstrated that saliva from Rhipicephalus sanguineus ticks inhibits the maturation of dendritic cells (DCs) stimulated with LPS. Here we examined the mechanism of this immune subversion, evaluating the effect of tick saliva on Toll-like receptor (TLR)-4 signalling pathway in bone marrow-derived DCs. We demonstrated that R. sanguineus tick saliva impairs maturation of DCs stimulated with LIPS, a TLR-4 ligand, leading to increased production of interleukin (IL)-10 and reduced synthesis of IL-12p70 and TNF-alpha. The immunomodulatory effect of the tick saliva on the production of pro-inflammatory cytokines by DCs stimulated with LPS was associated with the observation that tick saliva inhibits the activation of the ERK 1/2 and p38 MAP kinases. These effects were independent of the expression of TLR-4 on the surface of DCs. Additionally, saliva-treated DCs also presented a similar pattern of cytokine modulation in response to other TLR ligands. Since the recent literature reports that several parasites evade immune responses through TLR-2-mediated production of IL-10, we evaluated the effect of tick saliva on the percentage of TLR-2(+) DCs stimulated with the TLR-2 ligand lipoteicoic acid (LTA). The data showed that the population of DCs expressing TLR-2 was significantly increased in DCs treated with LTA plus saliva. In addition, tick saliva alone increased the expression of TLR-2 in a dose- and time-dependent manner. Our data suggest that tick saliva induces regulatory DCs, which secrete IL-10 and low levels of IL-12 and TNF-alpha when stimulated by TLR ligands. Such regulatory DCs are associated with expression of TLR-2 and inhibition of ERK and p38, which promotes the production of IL-10 and thus down-modulates the host`s immune response, possibly favouring susceptibility to tick infestations. (C) 2009 Elsevier B.V. All rights reserved.

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The characterization of a coffee gene encoding a protein similar to miraculin-like proteins, which are members of the plant Kunitz serine trypsin inhibitor (STI) family of proteinase inhibitors (PIs), is described. PIs are important proteins in plant defence against insects and in the regulation of proteolysis during plant development. This gene has high identity with the Richadella dulcifica taste-modifying protein miraculin and with the tomato protein LeMir; and was named as CoMir (Coffea miraculin). Structural protein modelling indicated that CoMir had structural similarities with the Kunitz STI proteins, but suggested specific folding structures. CoMir was up-regulated after coffee leaf miner (Leucoptera coffella) oviposition in resistant plants of a progeny derived from crosses between C. racemosa (resistant) and C. arabica (susceptible). Interestingly, this gene was down-regulated during coffee leaf miner herbivory in susceptible plants. CoMir expression was up-regulated after abscisic acid application and wounding stress and was prominent during the early stages of flower and fruit development. In situ hybridization revealed that CoMir transcripts accumulated in the anther tissues that display programmed cell death (tapetum, endothecium and stomium) and in the metaxylem vessels of the petals, stigma and leaves. In addition, the recombinant protein CoMir shows inhibitory activity against trypsin. According to the present results CoMir may act in proteolytic regulation during coffee development and in the defence against L. coffeella. The similarity of CoMir with other Kunitz STI proteins and the role of CoMir in plant development and plant stress are discussed.

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The goal of this work is to study and relate electrical and optical properties of diamond-like carbon (DLC) thin films for applications in electronic devices. DLC films were deposited in a reactive RF magnetron sputtering system on p-type silicon and glass substrates. The target was a 99.9999% pure, 6 in. diameter graphite plate and methane was used as processing gas. Eight DLC films were produced for each substrate, varying deposition time, the reactor pressure between 5 mTorr and 10 mTorr while the RF power was applied at 13.56 MHz and varied between 100, 150, 200 and 250W. After deposition, the films were analyzed by I-V and C-V measurements (Cheng et al. (2004) [1]) in order to determine the electric resistivity, photo-current response and dielectric constant, optical transmittance, used to find the optical gap by the Tauc method; and by photoluminescence analysis to determine the photoemission and confirm the optical band gap. These characteristics are compared and the influence of the deposition parameters is discussed. (C) 2011 Published by Elsevier B.V.

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The present study describes the direct regeneration of protocorm-like bodies (PLBs) in leaf explants of the tropical species Oncidium flexuosum. The explants were inoculated in a solid, modified Murashige and Skoog (MS) medium with different concentrations of the growth regulator thidiazuron (TDZ) and with or without 2,4-dichlorophenoxyacetic acid (2,4-D) and naphthalene acetic acid (NAA), and kept away from light or in a 16-h photoperiod. The presence of auxins, 2,4-D, and NAA inhibited the formation of PLBs. The highest frequency of explants that regenerated PLBs (80%) was obtained when they were maintained in a culture medium containing 1.5 mu M TDZ under dark conditions. In the same culture medium but under a 16-h photoperiod, 95% of the leaf explants presented necrosis. Therefore, darkness was crucial for the regeneration of PLBs in O. flexuosum leaf explants, which is in disagreement with the literature. PLBs developed from the division of epidermal and subepidermal cells mainly on the adaxial side of the apex region of the explant. Plants with well-developed leaves and roots grew after the PLBs were transferred to growth regulator-free medium under a 16-h photoperiod.

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Moniliophthora perniciosa is a hemibiotrophic fungus that causes witches` broom disease (WBD) in cacao. Marked dimorphism characterizes this fungus, showing a monokaryotic or biotrophic phase that causes disease symptoms and a later dikaryotic or saprotrophic phase. A combined strategy of DNA microarray, expressed sequence tag, and real-time reverse-transcriptase polymerase chain reaction analyses was employed to analyze differences between these two fungal stages in vitro. In all, 1,131 putative genes were hybridized with cDNA from different phases, resulting in 189 differentially expressed genes, and 4,595 reads were clusterized, producing 1,534 unigenes. The analysis of these genes, which represent approximately 21% of the total genes, indicates that the biotrophic-like phase undergoes carbon and nitrogen catabollite repression that correlates to the expression of phytopathogenicity genes. Moreover, downregulation of mitochondrial oxidative phosphorylation and the presence of a putative ngr1 of Saccharomyces cerevisiae could help explain its lower growth rate. In contrast, the saprotrophic mycelium expresses genes related to the metabolism of hexoses, ammonia, and oxidative phosphorylation, which could explain its faster growth. Antifungal toxins were upregulated and could prevent the colonization by competing fungi. This work significantly contributes to our understanding of the molecular mechanisms of WBD and, to our knowledge, is the first to analyze differential gene expression of the different phases of a hemibiotrophic fungus.

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Rapid alkalinization factor (RALF) is part of a growing family of small peptides with hormone characteristics in plants. Initially isolated from leaves of tobacco plants, RALF peptides can be found throughout the plant kingdom and they are expressed ubiquitously in plants. We took advantage of the small gene family size of RALF genes in sugarcane and the ordered cellular growth of the grass sugarcane leaves to gain information about the function of RALF peptides in plants. Here we report the isolation of two RALF peptides from leaves of sugarcane plants using the alkalinization assay. SacRALF1 was the most abundant and, when added to culture media, inhibited growth of microcalli derived from cell suspension cultures at concentrations as low as 0.1 mu M. Microcalli exposed to exogenous SacRALF1 for 5 days showed a reduced number of elongated cells. Only four copies of SacRALF genes were found in sugarcane plants. All four SacRALF genes are highly expressed in young and expanding leaves and show a low or undetectable level of expression in expanded leaves. In half-emerged leaf blades, SacRALF transcripts were found at high levels at the basal portion of the leaf and at low levels at the apical portion. Gene expression analyzes localize SacRALF genes in elongation zones of roots and leaves. Mature leaves, which are devoid of expanding cells, do not show considerable expression of SacRALF genes. Our findings are consistent with SacRALF genes playing a role in plant development potentially regulating tissue expansion.

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Farnesol (FOH) is a non-sterol isoprenoid produced by dephosphorylation of farnesyl pyrophosphate, a catabolite of the cholesterol biosynthetic pathway. These isoprenoids inhibit proliferation and induce apoptosis. It has been shown previously that FOH triggers morphological features characteristic of apoptosis in the filamentous fungus Aspergillus nidulans. Here, we investigate which pathways are influenced through FOH by examining the transcriptional profile of A. nidulans exposed to this isoprenoid. We observed decreased mRNA abundance of several genes involved in RNA processing and modification, transcription, translation, ribosomal structure and biogenesis, amino acid transport and metabolism, and ergosterol biosynthesis. We also observed increased mRNA expression of genes encoding a number of mitochondrial proteins and characterized in detail one of them, the aifA, encoding the Apoptosis-Inducing Factor (AIF)-like mitochondrial oxidoreductase. The Delta aifA mutant is more sensitive to FOH (about 8.0% and 0% survival when exposed to 10 and 100 mu M FOH respectively) than the wild type (about 97% and 3% survival when exposed to 10 and 100 mu M FOH respectively). These results suggest that AifA is possibly important for decreasing the effects of FOH and reactive oxygen species. Furthermore, we showed an involvement of autophagy and protein kinase C in A. nidulans FOH-induced apoptosis.