990 resultados para Electronic key


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Peroxisome proliferator-activated receptors (PPARs) act as metabolic sensors and central regulators of fat and glucose homeostasis. Furthermore, PPARγ has been implicated as major catabolic regulator of bone mass in mice and humans. However, a potential involvement of other PPAR subtypes in the regulation of bone homeostasis has remained elusive. Here we report a previously unrecognized role of PPARβ/δ as a key regulator of bone turnover and the crosstalk between osteoblasts and osteoclasts. In contrast to activation of PPARγ, activation of PPARβ/δ amplified Wnt-dependent and β-catenin-dependent signaling and gene expression in osteoblasts, resulting in increased expression of osteoprotegerin (OPG) and attenuation of osteoblast-mediated osteoclastogenesis. Accordingly, PPARβ/δ-deficient mice had lower Wnt signaling activity, lower serum concentrations of OPG, higher numbers of osteoclasts and osteopenia. Pharmacological activation of PPARβ/δ in a mouse model of postmenopausal osteoporosis led to normalization of the altered ratio of tumor necrosis factor superfamily, member 11 (RANKL, also called TNFSF11) to OPG, a rebalancing of bone turnover and the restoration of normal bone density. Our findings identify PPARβ/δ as a promising target for an alternative approach in the treatment of osteoporosis and related diseases.

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Flies (Diptera, blow flies, house flies, flesh flies, horse flies, cattle flies, deer flies, midges and mosquitoes) are among the four megadiverse insect orders. Several species quickly colonize human cadavers and are potentially useful in forensic studies. One of the major problems with carrion fly identification is the lack of taxonomists or available keys that can identify even the most common species sometimes resulting in erroneous identification. Here we present a key to the adults of 12 families of Diptera whose species are found on carrion, including human corpses. Also, a summary for the most common families of forensic importance in South America, along with a key to the most common species of Calliphoridae, Muscidae, and Fanniidae and to the genera of Sarcophagidae are provided. Drawings of the most important characters for identification are also included.

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Dendritic cells (DCs) are essential antigen-presenting cells for the induction of immunity against pathogens. However, HIV-1 spread is strongly enhanced in clusters of DCs and CD4(+) T cells. Uninfected DCs capture HIV-1 and mediate viral transfer to bystander CD4(+) T cells through a process termed trans-infection. Initial studies identified the C-type lectin DC-SIGN as the HIV-1 binding factor on DCs, which interacts with the viral envelope glycoproteins. Upon DC maturation, however, DC-SIGN is down-regulated, while HIV-1 capture and trans-infection is strongly enhanced via a glycoprotein-independent capture pathway that recognizes sialyllactose-containing membrane gangliosides. Here we show that the sialic acid-binding Ig-like lectin 1 (Siglec-1, CD169), which is highly expressed on mature DCs, specifically binds HIV-1 and vesicles carrying sialyllactose. Furthermore, Siglec-1 is essential for trans-infection by mature DCs. These findings identify Siglec-1 as a key factor for HIV-1 spread via infectious DC/T-cell synapses, highlighting a novel mechanism that mediates HIV-1 dissemination in activated tissues.

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A highly efficient synthesis of the biologically important fluorescent probe dansyl α-GalCer is presented. Key in our strategy is the incorporation of the fluorescent dansyl group at an early stage in the synthesis to facilitate in the monitoring and purification of intermediates via TLC and flash column chromatography, respectively, and the use of a high yielding α-selective glycosylation reaction between the phytosphingosine lipid and a galactosyl iodide donor. The ability of dansyl α-GalCer to activate iNKT cells and to serve as a fluorescent marker for the uptake of glycolipid by dendritic cells is also presented.

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The objective of this paper is to provide diagnosis and keys of the families and species, with illustrations of the main groups. A table of all related species recorded from South America is presented, including the substrate in which they were collected and their geographical distribution. The list comprises 221 species included in 15 families, of which 70% of the species are from Brazil. Scarabaeidae is the most diverse family with 121 species, followed by Staphylinidae with 68. Also we provide one database of Coleoptera species associated with carcasses in South America.

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A new species of Entomobryidae of the genus Seira Lubbock, S. paraibensis sp. nov. is described and illustrated. The type locality of the species is the municipality of Areia, state of Paraíba, Brazil. The species was found inhabiting the Atlantic forest litter and top soil environment. S. paraibensis sp. nov. resembles S. pseudoannulata in many morphological features. This is the sixth species of the genus found and described in Paraiba so far. A key with the 11 species of Seira registered so far in Paraíba is provided. Also a list with all species of the genus from Brazil is presented.

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Ants have evolved very complex societies and are key ecosystem members. Some ants, such as the fire ant Solenopsis invicta, are also major pests. Here, we present a draft genome of S. invicta, assembled from Roche 454 and Illumina sequencing reads obtained from a focal haploid male and his brothers. We used comparative genomic methods to obtain insight into the unique features of the S. invicta genome. For example, we found that this genome harbors four adjacent copies of vitellogenin. A phylogenetic analysis revealed that an ancestral vitellogenin gene first underwent a duplication that was followed by possibly independent duplications of each of the daughter vitellogenins. The vitellogenin genes have undergone subfunctionalization with queen- and worker-specific expression, possibly reflecting differential selection acting on the queen and worker castes. Additionally, we identified more than 400 putative olfactory receptors of which at least 297 are intact. This represents the largest repertoire reported so far in insects. S. invicta also harbors an expansion of a specific family of lipid-processing genes, two putative orthologs to the transformer/feminizer sex differentiation gene, a functional DNA methylation system, and a single putative telomerase ortholog. EST data indicate that this S. invicta telomerase ortholog has at least four spliceforms that differ in their use of two sets of mutually exclusive exons. Some of these and other unique aspects of the fire ant genome are likely linked to the complex social behavior of this species.

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Pseudopsis Newman, 1834 is a genus of Pseudopsinae with about 46 species distributed worldwide, five of which have been reported for South America. In this paper P. monica sp. nov. is described and illustrated based on specimens collected in Lima, Peru. A key to South American species of Pseudopsis and a catalog are also provided.

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Although dispersal is recognized as a key issue in several fields of population biology (such as behavioral ecology, population genetics, metapopulation dynamics or evolutionary modeling), these disciplines focus on different aspects of the concept and often make different implicit assumptions regarding migration models. Using simulations, we investigate how such assumptions translate into effective gene flow and fixation probability of selected alleles. Assumptions regarding migration type (e.g. source-sink, resident pre-emption, or balanced dispersal) and patterns (e.g. stepping-stone versus island dispersal) have large impacts when demes differ in sizes or selective pressures. The effects of fragmentation, as well as the spatial localization of newly arising mutations, also strongly depend on migration type and patterns. Migration rate also matters: depending on the migration type, fixation probabilities at an intermediate migration rate may lie outside the range defined by the low- and high-migration limits when demes differ in sizes. Given the extreme sensitivity of fixation probability to characteristics of dispersal, we underline the importance of making explicit (and documenting empirically) the crucial ecological/ behavioral assumptions underlying migration models.

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To describe the psychological profile of renal transplant adolescents compared to healthy peers and to adolescents with CKD, three groups of adolescents aged 12-18 yr were selected: TX, CX, and adolescents with CKD. Psychiatric symptoms and disorders were evaluated through direct interviews (K-SADS-PL) and self-report questionnaires (YSR and CBCL). Forty TX (14 LRD and 26 DD transplant recipients), 40 CX and 20 CKD were included. Twelve of 40 (30%) TX, three of 20 (15%) CKD, and three of 40 (7.5%) CX had a history of learning difficulties (p = 0.03). Compared to CX, TX had lower total YSR competencies score (p = 0.028) and lower total CBCL competencies score (p = 0.003). Twenty-six of 40 (65%) TX, 12 of 20 (60%) CKD and 15 of 40 (37.5%) CX (p = 0.038) met DSM-IV diagnostic criteria for lifetime psychiatric disorder, with rates of depressive disorder of 35% among TX and CKD compared to 15.2% among CX (p = 0.043). Eight of 40 (20%) TX had a history of simple phobia. Nine of 40 (22.5%) TX met diagnostic criteria for ADHD as compared to one of 20 (5%) CKD and three of 40 (7.5%) CX. In the TX group, we found no significant differences in educational and psychiatric variables between LRD and DD. In conclusion, we found a high prevalence of psychiatric morbidity (depression, phobia, ADHD), educational impairment and social competence problems in the TX group. CKD scored in between TX and CX on most measures.

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AIMS: A literature review of existing research on the prevalence of alcohol use disorders (AUDs) and availability of alcohol interventions in Europe was conducted. The review also explored what is known about the gap between need and provision of alcohol interventions in Europe. METHODS: The review search strategy included: (i) descriptive studies of alcohol intervention systems in Europe; (ii) studies of alcohol service provision in Europe; and (iii) studies of prevalence of AUD and alcohol needs assessment in Europe. RESULTS: Europe has a relatively high level of alcohol consumption and the resulting disabilities are the highest in the world. Most research on implementation of alcohol interventions in Europe has been restricted to screening and brief interventions. Alcohol needs assessment methodology has been developed but has not been applied in comparative studies across countries in Europe. CONCLUSIONS: This review points to key gaps in knowledge related to alcohol interventions in Europe. There is a lack of comparative data on variations in alcohol treatment systems across European countries and there is also a lack of comparative data on the prevalence of alcohol use disorders across European countries and the relative gap between need and access to treatment. The forthcoming Alcohol Measures for Public Health Research Alliance (AMPHORA) research project work package on 'Early identification and treatment' aims to address these gaps.

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A key to 51 Australasian and Oceanian genera of Muscidae is given. The Catalogue of Australasian and Oceanian Diptera and its on line version last reviewed in May 2007 were used as taxonomic guides. Some more recently synonyms and taxonomic changes were updated. For each genus, a brief diagnosis, number of valid species in these regions and comments, when pertinent, are also included. Some morphological diagnostic characteres are illustrated in order to help the use of the key.

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Summary.  Hepatitis C virus (HCV) nonstructural protein 3-4A (NS3-4A) is a complex composed of NS3 and its cofactor NS4A. It harbours serine protease as well as NTPase/RNA helicase activities and is essential for viral polyprotein processing, RNA replication and virion formation. Specific inhibitors of the NS3-4A protease significantly improve sustained virological response rates in patients with chronic hepatitis C when combined with pegylated interferon-α and ribavirin. The NS3-4A protease can also target selected cellular proteins, thereby blocking innate immune pathways and modulating growth factor signalling. Hence, NS3-4A is not only an essential component of the viral replication complex and prime target for antiviral intervention but also a key player in the persistence and pathogenesis of HCV. This review provides a concise update on the biochemical and structural aspects of NS3-4A, its role in the pathogenesis of chronic hepatitis C and the clinical development of NS3-4A protease inhibitors.

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The kidney is a key organ in the maintenance of ion and fluid homeostasis and specific transport systems localized along the nephron guarantee this function. Due to its large functional heterogeneity, experiments on the whole organ level cannot be easily performed, and thus more refined tools are needed, like for example the development of specific recombination systems to gain knowledge on the physiological role of single proteins implicated in ion transport. This review introduces the transgenic technology developed over the past decades, and then focuses on recent strategies for generating kidney-specific gene targeting, over-expression, and gene ablation in mice, that will help to understand the physiological role of proteins implicated in salt and water balance in the kidney.

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A new species of soft scale insect from Mexico, Toumeyella fontanai Kondo & Pellizzari sp. nov. is des-cribed and illustrated. A taxonomic key to the species of scale insects of the genus Toumeyella Cockerell known in Mexico is provided.