945 resultados para Autonomes Parvovirus, Dendritische Zelle, Toll-like Rezeptoren, Tumorimmunologie
Resumo:
Alcohol dependence is a debilitating disorder with current therapies displaying limited efficacy and/or compliance. Consequently, there is a critical need for improved pharmacotherapeutic strategies to manage alcohol use disorders (AUDs). Previous studies have shown that the development of alcohol dependence involves repeated cycles of binge-like ethanol intake and abstinence. Therefore, we used a model of binge-ethanol consumption (drinking-in-the-dark) in mice to test the effects of compounds known to modify the activity of neurotransmitters implicated in alcohol addiction. From this, we have identified the FDA-approved antihypertensive drug pindolol, as a potential candidate for the management of AUDs. We show that the efficacy of pindolol to reduce ethanol consumption is enhanced following long-term (12-weeks) binge-ethanol intake, compared to short-term (4-weeks) intake. Furthermore, pindolol had no effect on locomotor activity or consumption of the natural reward sucrose. Because pindolol acts as a dual beta-adrenergic antagonist and 5-HT1A/1B partial agonist, we examined its effect on spontaneous synaptic activity in the basolateral amygdala (BLA), a brain region densely innervated by serotonin- and norepinephrine-containing fibres. Pindolol increased spontaneous excitatory post-synaptic current frequency in BLA principal neurons from long-term ethanol consuming mice but not naïve mice. Additionally, this effect was blocked by the 5-HT1A/1B receptor antagonist methiothepin, suggesting that altered serotonergic activity in the BLA may contribute to the efficacy of pindolol to reduce ethanol intake following long-term exposure. Although further mechanistic investigations are required, this study demonstrates the potential of pindolol as a new treatment option for AUDs that can be fast-tracked into human clinical studies.
Resumo:
Impulsivity and hyperactivity share common ground with numerous mental disorders, including schizophrenia. Recently, a population-specific serotonin 2B (5-HT2B) receptor stop codon (ie, HTR2B Q20*) was reported to segregate with severely impulsive individuals, whereas 5-HT2B mutant (Htr2B−/−) mice also showed high impulsivity. Interestingly, in the same cohort, early-onset schizophrenia was more prevalent in HTR2B Q*20 carriers. However, the putative role of 5-HT2B receptor in the neurobiology of schizophrenia has never been investigated. We assessed the effects of the genetic and the pharmacological ablation of 5-HT2B receptors in mice subjected to a comprehensive series of behavioral test screenings for schizophrenic-like symptoms and investigated relevant dopaminergic and glutamatergic neurochemical alterations in the cortex and the striatum. Domains related to the positive, negative, and cognitive symptom clusters of schizophrenia were affected in Htr2B−/− mice, as shown by deficits in sensorimotor gating, in selective attention, in social interactions, and in learning and memory processes. In addition, Htr2B−/− mice presented with enhanced locomotor response to the psychostimulants dizocilpine and amphetamine, and with robust alterations in sleep architecture. Moreover, ablation of 5-HT2B receptors induced a region-selective decrease of dopamine and glutamate concentrations in the dorsal striatum. Importantly, selected schizophrenic-like phenotypes and endophenotypes were rescued by chronic haloperidol treatment. We report herein that 5-HT2B receptor deficiency confers a wide spectrum of antipsychotic-sensitive schizophrenic-like behavioral and psychopharmacological phenotypes in mice and provide first evidence for a role of 5-HT2B receptors in the neurobiology of psychotic disorders
Resumo:
The identification of "stay-green" in sorghum and its positive correlation with yield increases has encouraged attempts to incorporate "stay-green"-like traits into the genomes of other commercially important cereal crops. However, knowledge on the effects of "stay-green" expression on grain quality under extreme physiological stress is limited. This study examines impacts of "stay-green"-like expression on starch biosynthesis in barley (Hordeum vulgare L.) grain under mild, severe, and acute water stress conditions induced at anthesis. The proportions of long amylopectin branches and amylose branches in the grain of Flagship (a cultivar without "stay-green"-like characteristics) were higher at low water stress, suggesting that water stress affects starch biosynthesis in grain, probably due to early termination of grain fill. The changes in long branches can affect starch properties, such as the rates of enzymatic degradation, and hence its nutritional value. By contrast, grain from the "stay-green"-like cultivar (ND24260) did not show variation in starch molecular structure under the different water stress levels. The results indicate that the cultivar with "stay-green"-like traits has a greater potential to maintain starch biosynthesis and quality in grain during drought conditions, making the "stay-green"-like traits potentially useful in ensuring food security. (C) 2013 Elsevier Ltd. All rights reserved.
Resumo:
The memoirs were written in 2000 in California and contains some of the author's diary entries during the years of the family's emigration and reminiscences of the author's father. Detailed description of family history going back to the early 19th century. The author's grandfather Moses Stern had a rawproduct business in Gelsenkirchen, Westphalia. His father Max Stern took his graduate exam (Abitur) at the Jacobsohn boarding school in 1904 and was sent to a business school in Brussles, Belgium. Work in the family business M. Stern AG. World War One and rise of the family business with branches throughout Germany and offices in New York, London, Milan and Stockholm. Due to political unrest at the end of the war the business administration moved to Essen. Description of the family background of Beate Herzberg, the author's mother. Courtship of his parents and marriage in 1922. Birth of his sister Annelore in 1923. Martin Stern was born in 1924. Description of the family household and domestic life in a well-to-do family the 1920s. Friday visits to the synagogue and celebration of Jewish holidays. Vacations at the North sea and skiinig in the Alps. Martin attended a Jewish elementary school. Rising National Socialism. After Hitler came to power in 1933 the author's father immediately started preparations for the family's emigration, but was persuaded to stay by his family. Life under National Socialism. Martin attended Gymnasium and was one of only two Jewish students in his class. Antisemitic incidents. Private lessons in piano and Hebrew. Bar Mitzvah in 1937. Recollections of performances of the Kulturbund.
Resumo:
Proteins are complex biomacromolecules playing fundamental roles in the physiological processes of all living organisms. They function as structural units, enzymes, transporters, process regulators, and signal transducers. Defects in protein functions often derive from genetic mutations altering the protein structure, and impairment of essential protein functions manifests itself as pathological conditions. Proteins operate through interactions, and all protein functions depend on protein structure. In order to understand biological mechanisms at the molecular level, one has to know the structures of the proteins involved. This thesis covers structural and functional characterization of human filamins. Filamins are actin-binding and -bundling proteins that have numerous interaction partners. In addition to their actin-organizing functions, filamins are also known to have roles in cell adhesion and locomotion, and to participate in the logistics of cell membrane receptors, and in the coordination of intracellular signaling pathways. Filamin mutations in humans induce severe pathological conditions affecting the brain, bones, limbs, and the cardiovascular system. Filamins are large modular proteins composed of an N-terminal actin-binding domain and 24 consecutive immunoglobulin-like domains (IgFLNs). Nuclear magnetic resonance (NMR) spectroscopy is a versatile method of gaining insight into protein structure, dynamics and interactions. NMR spectroscopy was employed in this thesis to study the atomic structure and interaction mechanisms of C-terminal IgFLNs, which are known to house the majority of the filamin interaction sites. The structures of IgFLN single-domains 17 and 23 and IgFLN domain pairs 16-17 and 18-19 were determined using NMR spectroscopy. The structures of domain pairs 16 17 and 18 19 both revealed novel domain domain interaction modes of IgFLNs. NMR titrations were employed to characterize the interactions of filamins with glycoprotein Ibα, FilGAP, integrin β7 and dopamine receptors. Domain packing of IgFLN domain sextet 16 21 was further characterized using residual dipolar couplings and NMR relaxation analysis. This thesis demonstrates the versatility and potential of NMR spectroscopy in structural and functional studies of multi-domain proteins.
Resumo:
Project evaluation is a process of measuring costs, benefits, risks and uncertainties for the purpose of decision-making by estimating and assessing impacts of the project to the community. The effects of impacts of toll roads are similar but different from the general non-tolled roads. Project evaluation methodologies are extensively studied and applied to various transport infrastructure projects. However, there is no definitive methodology to evaluate toll roads. This review discusses the impacts of toll roads then reviews the limitations of existing project evaluation methodologies when evaluating toll road impacts. The review identified gaps of knowledge of toll evaluations. First, the treatment of toll in project evaluation, particularly in Cost-Benefit Analysis requires further study to explore the appropriate methodology. Secondly, the project evaluation methodology needs to place strong emphasis on empirically based risk and uncertainty assessment. Addressing the limitations of the existing project evaluation methodologies leads to improvements of the methodology in practical level as well as fills the gap of knowledge of project evaluation for toll roads with respect to net impacts to the community.
Resumo:
Project evaluation is a process of measuring costs, benefits, risks and uncertainties for the purpose of decision-making by estimating and assessing impacts of the project to the community. The effects of impacts of toll roads are similar but different from the general non-tolled roads. Project evaluation methodologies are extensively studied and applied to various transport infrastructure projects. However, there is no definitive methodology to evaluate toll roads. This review discusses the impacts of toll roads then reviews the limitations of existing project evaluation methodologies when evaluating toll road impacts. The review identified gaps of knowledge of toll evaluations. First, the treatment of toll in project evaluation, particularly in Cost-Benefit Analysis requires further study to explore the appropriate methodology. Secondly, the project evaluation methodology needs to place strong emphasis on empirically based risk and uncertainty assessment. Addressing the limitations of the existing project evaluation methodologies leads to improvements of the methodology in practical level as well as fills the gap of knowledge of project evaluation for toll roads with respect to net impacts to the community.
Resumo:
Most major cities around the world experience periods of elevated air pollution levels, which exceed international health-based air quality standards (Kumar et al., 2013). Although it is a global problem, some of the highest air pollution levels are found in rapidly expanding cities in India and China. The sources, emissions, transformations and broad effects of meteorology on air pollution are reasonably well accounted in air quality control strategies in many developed cities; however these key factors remain poorly constrained in the growing cities of countries with emerging economies. We focus here on Delhi, one of the largest global population centres, which faces particular air pollution challenges, now and in the future.
Resumo:
Human parvovirus B19 is a minute ssDNA virus causing a wide variety of diseases, including erythema infectiosum, arthropathy, anemias, and fetal death. After primary infection, genomic DNA of B19 has been shown to persist in solid tissues of not only symptomatic but also of constitutionally healthy, immunocompetent individuals. In this thesis, the viral DNA was shown to persist as an apparently intact molecule of full length, and without persistence-specific mutations. Thus, although the mere presence of B19 DNA in tissue can not be used as a diagnostic criterion, a possible role in the pathogenesis of diseases e.g. through mRNA or protein production can not be excluded. The molecular mechanism, the host-cell type and the possible clinical significance of B19 DNA tissue persistence are yet to be elucidated. In the beginning of this work, the B19 genomic sequence was considered highly conserved. However, new variants were found: V9 was detected in 1998 in France, in serum of a child with aplastic crisis. This variant differed from the prototypic B19 sequences by ~10 %. In 2002 we found, persisting in skin of constitutionally healthy humans, DNA of another novel B19 variant, LaLi. Genetically this variant differed from both the prototypic sequences and the variant V9 also by ~10%. Simultaneously, B19 isolates with DNA sequences similar to LaLi were introduced by two other groups, in the USA and France. Based on phylogeny, a classification scheme based on three genotypes (B19 types 1-3) was proposed. Although the B19 virus is mainly transmitted via the respiratory route, blood and plasma-derived products contaminated with high levels of B19 DNA have also been shown to be infectious. The European Pharmacopoeia stipulates that, in Europe, from the beginning of 2004, plasma pools for manufacture must contain less than 104 IU/ml of B19 DNA. Quantitative PCR screening is therefore a prerequisite for restriction of the B19 DNA load and obtaining of safe plasma products. Due to the DNA sequence variation among the three B19 genotypes, however, B19 PCR methods might fail to detect the new variants. We therefore examined the suitability of the two commercially available quantitative B19 PCR tests, LightCycler-Parvovirus B19 quantification kit (Roche Diagnostics) and RealArt Parvo B19 LC PCR (Artus), for detection, quantification and differentiation of the three B19 types known, including B19 types 2 and 3. The former method was highly sensitive for detection of the B19 prototype but was not suitable for detection of types 2 and 3. The latter method detected and differentiated all three B19 virus types. However, one of the two type-3 strains was detected at a lower sensitivity. Then, we assessed the prevalence of the three B19 virus types among Finnish blood donors, by screening pooled plasma samples derived from >140 000 blood-donor units: none of the pools contained detectable levels of B19 virus types 2 or 3. According to the results of other groups, B19 type 2 was absent also among Danish blood-donors, and extremely rare among symptomatic European patients. B19 type 3 has been encountered endemically in Ghana and (apparently) in Brazil, and sporadical cases have been detected in France and the UK. We next examined the biological characteristics of these virus types. The p6 promoter regions of virus types 1-3 were cloned in front of a reporter gene, the constructs were transfected into different cell lines, and the promoter activities were measured. As a result, we found that the activities of the three p6 promoters, although differing in sequence by >20%, were of equal strength, and most active in B19-permissive cells. Furthermore, the infectivity of the three B19 types was examined in two B19-permissive cell lines. RT-PCR revealed synthesis of spliced B19 mRNAs, and immunofluorescence verified the production of NS1 and VP proteins in the infected cells. These experiments suggested similar host-cell tropism and showed that the three virus types are strains of the same species, i.e. human parvovirus B19. Last but not least, the sera from subjects infected in the past either with B19 type 1 or type 2 (as evidenced by tissue persistence of the respective DNAs), revealed in VP1/2- and VP2-EIAs a 100 % cross-reactivity between virus types 1 and 2. These results, together with similar studies by others, indicate that the three B19 genotypes constitute a single serotype.
Resumo:
The genome of the human pathogen Entamoeba histolytica, a primitive protist, contains non-long terminal repeat retrotransposable elements called EhLINEs. These encode reverse transcriptase and endonuclease required for retrotransposition. The endonuclease shows sequence similarity with bacterial restriction endonucleases. Here we report the salient enzymatic features of one such endonuclease. The kinetics of an EhLINE1-encoded endonuclease catalyzed reaction, determined under steady-state and single-turnover conditions, revealed a significant burst phase followed by a slower steady-state phase, indicating that release of product could be the slower step in this reaction. For circular supercoiled DNA the K-m was 2.6 x 10-8 m and the k(cat) was 1.6 x 10-2 sec-1. For linear E. histolytica DNA substrate the K-m and k(cat) values were 1.3 x 10-8 m and 2.2 x 10-4 sec-1 respectively. Single-turnover reaction kinetics suggested a noncooperative mode of hydrolysis. The enzyme behaved as a monomer. While Mg2+ was required for activity, 60% activity was seen with Mn2+ and none with other divalent metal ions. Substitution of PDX12-14D (a metal-binding motif) with PAX(12-14)D caused local conformational change in the protein tertiary structure, which could contribute to reduced enzyme activity in the mutated protein. The protein underwent conformational change upon the addition of DNA, which is consistent with the known behavior of restriction endonucleases. The similarities with bacterial restriction endonucleases suggest that the EhLINE1-encoded endonuclease was possibly acquired from bacteria through horizontal gene transfer. The loss of strict sequence specificity for nicking may have been subsequently selected to facilitate spread of the retrotransposon to intergenic regions of the E. histolytica genome.
Resumo:
Nuclear magnetic resonance (NMR) spectroscopy provides us with many means to study biological macromolecules in solution. Proteins in particular are the most intriguing targets for NMR studies. Protein functions are usually ascribed to specific three-dimensional structures but more recently tails, long loops and non-structural polypeptides have also been shown to be biologically active. Examples include prions, -synuclein, amylin and the NEF HIV-protein. However, conformational preferences in coil-like molecules are difficult to study by traditional methods. Residual dipolar couplings (RDCs) have opened up new opportunities; however their analysis is not trivial. Here we show how to interpret RDCs from these weakly structured molecules. The most notable residual dipolar couplings arise from steric obstruction effects. In dilute liquid crystalline media as well as in anisotropic gels polypeptides encounter nematogens. The shape of a polypeptide conformation limits the encounter with the nematogen. The most elongated conformations may come closest whereas the most compact remain furthest away. As a result there is slightly more room in the solution for the extended than for the compact conformations. This conformation-dependent concentration effect leads to a bias in the measured data. The measured values are not arithmetic averages but essentially weighted averages over conformations. The overall effect can be calculated for random flight chains and simulated for more realistic molecular models. Earlier there was an implicit thought that weakly structured or non-structural molecules would not yield to any observable residual dipolar couplings. However, in the pioneering study by Shortle and Ackerman RDCs were clearly observed. We repeated the study for urea-denatured protein at high temperature and also observed indisputably RDCs. This was very convincing to us but we could not possibly accept the proposed reason for the non-zero RDCs, namely that there would be some residual structure left in the protein that to our understanding was fully denatured. We proceeded to gain understanding via simulations and elementary experiments. In measurements we used simple homopolymers with only two labelled residues and we simulated the data to learn more about the origin of RDCs. We realized that RDCs depend on the position of the residue as well as on the length of the polypeptide. Investigations resulted in a theoretical model for RDCs from coil-like molecules. Later we extended the studies by molecular dynamics. Somewhat surprisingly the effects are small for non-structured molecules whereas the bias may be large for a small compact protein. All in all the work gave clear and unambiguous results on how to interpret RDCs as structural and dynamic parameters of weakly structured proteins.
Resumo:
The modern diet has become highly sweetened, resulting in unprecedented levels of sugar consumption, particularly among adolescents. While chronic long-term sugar intake is known to contribute to the development of metabolic disorders including obesity and type II diabetes, little is known regarding the direct consequences of long-term, binge-like sugar consumption on the brain. Because sugar can cause the release of dopamine in the nucleus accumbens (NAc) similarly to drugs of abuse, we investigated changes in the morphology of neurons in this brain region following short- (4 weeks) and long-term (12 weeks) binge-like sucrose consumption using an intermittent two-bottle choice paradigm. We used Golgi-Cox staining to impregnate medium spiny neurons (MSNs) from the NAc core and shell of short- and long-term sucrose consuming rats and compared these to age-matched water controls. We show that prolonged binge-like sucrose consumption significantly decreased the total dendritic length of NAc shell MSNs compared to age-matched control rats. We also found that the restructuring of these neurons resulted primarily from reduced distal dendritic complexity. Conversely, we observed increased spine densities at the distal branch orders of NAc shell MSNs from long-term sucrose consuming rats. Combined, these results highlight the neuronal effects of prolonged binge-like intake of sucrose on NAc shell MSN morphology.
Resumo:
In this communication, we report the spontaneous and reversible in vitro self-assembly of a polypeptide fragment derived from the C-terminal domain of Insulin-like Growth Factor Binding Protein (IGFBP-2) into soluble nanotubular structures several micrometres long via a mechanism involving inter-molecular disulfide bonds and exhibiting enhanced fluorescence.
Resumo:
'Like A Burden' was an exhibition developed and presented for Metro Arts Galleries in 2015. It drew together several large scale fabric works 'Heavy Thinking'; 'Quick Draw II' and 'Well Hung' within the gallery space, along with a large series of ink and pencil drawings and a lecture performance recorded and projected as a digital video. This body of work foregrounds the activist feminist voice through quotation, citation and reiteration and is part of a broader practice strategy to re-perform a subjective feminist archive.