986 resultados para Gill filaments
Resumo:
Senataxin, mutated in the human genetic disorder ataxia with oculomotor apraxia type 2 (AOA2), plays an important role in maintaining genome integrity by coordination of transcription, DNA replication, and the DNA damage response. We demonstrate that senataxin is essential for spermatogenesis and that it functions at two stages in meiosis during crossing-over in homologous recombination and in meiotic sex chromosome inactivation (MSCI). Disruption of the Setx gene caused persistence of DNA double-strand breaks, a defect in disassembly of Rad51 filaments, accumulation of DNA:RNA hybrids (R-loops), and ultimately a failure of crossing-over. Senataxin localised to the XY body in a Brca1-dependent manner, and in its absence there was incomplete localisation of DNA damage response proteins to the XY chromosomes and ATR was retained on the axial elements of these chromosomes, failing to diffuse out into chromatin. Furthermore persistence of RNA polymerase II activity, altered ubH2A distribution, and abnormal XY-linked gene expression in Setx⁻/⁻ revealed an essential role for senataxin in MSCI. These data support key roles for senataxin in coordinating meiotic crossing-over with transcription and in gene silencing to protect the integrity of the genome.
Resumo:
Background Research has identified associations between serum 25(OH)D and a range of clinical outcomes in chronic kidney disease and wider populations. The present study aimed to investigate vitamin D deficiency/insufficiency in dialysis patients and the relationship with vitamin D intake and sun exposure. Methods A cross-sectional study was used. Participants included 30 peritoneal dialysis (PD) (43.3% male; 56.87 ± 16.16 years) and 26 haemodialysis (HD) (80.8% male; 63.58 ± 15.09 years) patients attending a department of renal medicine. Explanatory variables were usual vitamin D intake from diet/supplements (IU day−1) and sun exposure (min day−1). Vitamin D intake, sun exposure and ethnic background were assessed by questionnaire. Weight, malnutrition status and routine biochemistry were also assessed. Data were collected during usual department visits. The main outcome measure was serum 25(OH)D (nm). Results Prevalence of inadequate/insufficient vitamin D intake differed between dialysis modality, with 31% and 43% found to be insufficient (<50 nm) and 4% and 33% found to be deficient (<25 nm) in HD and PD patients, respectively (P < 0.001). In HD patients, there was a correlation between diet and supplemental vitamin D intake and 25(OH)D (ρ = 0.84, P < 0.001) and average sun exposure and 25(OH)D (ρ = 0.50, P < 0.02). There were no associations in PD patients. The results remained significant for vitamin D intake after multiple regression, adjusting for age, gender and sun exposure. Conclusions The results highlight a strong association between vitamin D intake and 25(OH)D in HD but not PD patients, with implications for replacement recommendations. The findings indicate that, even in a sunny climate, many dialysis patients are vitamin D deficient, highlighting the need for exploration of determinants and consequences.
Resumo:
ESCRT-III proteins catalyze membrane fission during multi vesicular body biogenesis, budding of some enveloped viruses and cell division. We suggest and analyze a novel mechanism of membrane fission by the mammalian ESCRT-III subunits CHMP2 and CHMP3. We propose that the CHMP2-CHMP3 complexes self-assemble into hemi-spherical dome-like structures within the necks of the initial membrane buds generated by CHMP4 filaments. The dome formation is accompanied by the membrane attachment to the dome surface, which drives narrowing of the membrane neck and accumulation of the elastic stresses leading, ultimately, to the neck fission. Based on the bending elastic model of lipid bilayers, we determine the degree of the membrane attachment to the dome enabling the neck fission and compute the required values of the protein-membrane binding energy. We estimate the feasible values of this energy and predict a high efficiency for the CHMP2-CHMP3 complexes in mediating membrane fission. We support the computational model by electron tomography imaging of CHMP2-CHMP3 assemblies in vitro. We predict a high efficiency for the CHMP2-CHMP3 complexes in mediating membrane fission.
Resumo:
Since the establishment of Australia’s earliest formal studies in landscape architecture, landscape planning has been a traditional focus within post-graduate studies at QUT. Study in this area has evolved from an earlier emphasis on applied physical geography through to traditional techniques and processes in visual assessment and management. The emphasis on these techniques has shifted again to a more complex exploration of natural, economic, social and cultural landscapes. Recently, the School has explored more innovative and complex dimensions of human and natural landscapes. This has involved a focus on particular regions under pressure from local social and economic change. These have included the under-threat ‘picturesque’ landscapes of the Blackall Range and the Tweed Valley. Attempts to bridge the institution and the landscape have unearthed, through a studio focus, strong connections with notions of sustainable villages, roadside interpretation, way finding, local economic initiatives, special area creation, cultural heritage brokering and ecological enhancements. These initiatives have spanned both local practice interests and academic pursuits. Central to this exploration is the concept of problem solving through the investigation of the concept of ‘multiple scales’. An open, yet intensive program is being developed with a team of ‘futurist’ practitioners offering a range of experiences and perspectives to students. The program is being increasingly linked to design studios so that landscape planning and landscape design form a fabric of inquiry that works towards reclaiming complex landscapes.
Resumo:
What is ‘best practice’ when it comes to managing intellectual property rights in participatory media content? As commercial media and entertainment business models have increasingly come to rely upon the networked productivity of end-users (Banks and Humphreys 2008) this question has been framed as a problem of creative labour made all the more precarious by changing employment patterns and work cultures of knowledge-intensive societies and globalising economies (Banks, Gill and Taylor 2014). This paper considers how the problems of ownership are addressed in non-commercial, community-based arts and media contexts. Problems of labour are also manifest in these contexts (for example, reliance on volunteer labour and uncertain economic reward for creative excellence). Nonetheless, managing intellectual property rights in collaborative creative works that are created in community media and arts contexts is no less challenging or complex than in commercial contexts. This paper takes as its focus a particular participatory media practice known as ‘digital storytelling’. The digital storytelling method, formalised by the Centre for Digital Storytelling (CDS) from the mid-1990s, has been internationally adopted and adapted for use in an open-ended variety of community arts, education, health and allied services settings (Hartley and McWilliam 2009; Lambert 2013; Lundby 2008; Thumin 2012). It provides a useful point of departure for thinking about a range of collaborative media production practices that seek to address participation ‘gaps’ (Jenkins 2006). However the outputs of these activities, including digital stories, cannot be fully understood or accurately described as user-generated content. For this reason, digital storytelling is taken here to belong to a category of participatory media activity that has been described as ‘co-creative’ media (Spurgeon 2013) in order to improve understanding of the conditions of mediated and mediatized participation (Couldry 2008). This paper reports on a survey of the actual copyrighting practices of cultural institutions and community-based media arts practitioners that work with digital storytelling and similar participatory content creation methods. This survey finds that although there is a preference for Creative Commons licensing a great variety of approaches are taken to managing intellectual property rights in co-creative media. These range from the use of Creative Commons licences (for example, Lambert 2013, p.193) to retention of full copyrights by storytellers, to retention of certain rights by facilitating organisations (for example, broadcast rights by community radio stations and public service broadcasters), and a range of other shared rights arrangements between professional creative practitioners, the individual storytellers and communities with which they collaborate, media outlets, exhibitors and funders. This paper also considers how aesthetic and ethical considerations shape responses to questions of intellectual property rights in community media arts contexts. For example, embedded in the CDS digital storytelling method is ‘a critique of power and the numerous ways that rank is unconsciously expressed in engagements between classes, races and gender’ (Lambert 117). The CDS method privileges the interests of the storyteller and, through a transformative workshop process, aims to generate original individual stories that, in turn, reflect self-awareness of ‘how much the way we live is scripted by history, by social and cultural norms, by our own unique journey through a contradictory, and at times hostile, world’ (Lambert 118). Such a critical approach is characteristic of co-creative media practices. It extends to a heightened awareness of the risks of ‘story theft’ and the challenges of ownership and informs ideas of ‘best practice’ amongst creative practitioners, teaching artists and community media producers, along with commitments to achieving equitable solutions for all participants in co-creative media practice (for example, Lyons-Reid and Kuddell nd.). Yet, there is surprisingly little written about the challenges of managing intellectual property produced in co-creative media activities. A dialogic sense of ownership in stories has been identified as an indicator of successful digital storytelling practice (Hayes and Matusov 2005) and is helpful to grounding the more abstract claims of empowerment for social participation that are associated with co-creative methods. Contrary to the ‘change from below’ philosophy that underpins much thinking about co-creative media, however, discussions of intellectual property usually focus on how methods such as digital storytelling contribute to the formation of copyright law-compliant subjects, particularly when used in educational settings (for example, Ohler nd.). This also exposes the reliance of co-creative methods on the creative assets storytellers (rather than on the copyrighted materials of the media cultures of storytellers) as a pragmatic response to the constraints that intellectual property right laws impose on the entire category of participatory media. At the level of practical politics, it also becomes apparent that co-creative media practitioners and storytellers located in copyright jurisdictions governed by ‘fair use’ principles have much greater creative flexibility than those located in jurisdictions governed by ‘fair dealing’ principles.
Resumo:
In order for cells to stop moving, they must synchronously stabilize actin filaments and their associated focal adhesions. How these two structures are coordinated in time and space is not known. We show here that the actin association protein Tm5NM1, which induces stable actin filaments, concurrently suppresses the trafficking of focal-adhesion-regulatory molecules. Using combinations of fluorescent biosensors and fluorescence recovery after photobleaching (FRAP), we demonstrate that Tm5NM1 reduces the level of delivery of Src kinase to focal adhesions, resulting in reduced phosphorylation of adhesion-resident Src substrates. Live imaging of Rab11-positive recycling endosomes that carry Src to focal adhesions reveals disruption of this pathway. We propose that tropomyosin synchronizes adhesion dynamics with the cytoskeleton by regulating actin-dependent trafficking of essential focal-adhesion molecules.
Resumo:
Axon targeting during the development of the olfactory system is not always accurate, and numerous axons overextend past the target layer into the deeper layers of the olfactory bulb. To date, the fate of the mis-targeted axons has not been determined. We hypothesized that following overextension, the axons degenerate, and cells within the deeper layers of the olfactory bulb phagocytose the axonal debris. We utilized a line of transgenic mice that expresses ZsGreen fluorescent protein in primary olfactory axons. We found that overextending axons closely followed the filaments of radial glia present in the olfactory bulb during embryonic development. Following overextension into deeper layers of the olfactory bulb, axons degenerated and radial glia responded by phagocytosing the resulting debris. We used in vitro analysis to confirm that the radial glia had phagocytosed debris from olfactory axons. We also investigated whether the fate of overextending axons was altered when the development of the olfactory bulb was perturbed. In mice that lacked Sox10, a transcription factor essential for normal olfactory bulb development, we observed a disruption to the morphology and positioning of radial glia and an accumulation of olfactory axon debris within the bulb. Our results demonstrate that during early development of the olfactory system, radial glia play an important role in removing overextended axons from the deeper layers of the olfactory bulb.
Resumo:
Background: Individuals who fear falling may restrict themselves from performing certain activities and may increase their risk of falling. Such fear, reflected in the form of falls efficacy, has been measured in only a small number of studies measuring the effectiveness of exercise interventions in the elderly. This may be due to the various types of exercise that can be performed. Hence the effectiveness of exercise on falls efficacy is relatively understudied. Therefore, there is a need to measure falls efficacy as an outcome variable when conducting exercise interventions in the elderly. Methods: A total of 43 elderly community-dwelling volunteers were recruited and randomly allocated to a conventional exercise intervention, a holistic exercise intervention, or a control group. The interventions were performed 2 days per week for 10 weeks. Falls efficacy was measured at baseline and at the completion of the interventions using the Modified Falls Efficacy Scale (MFES). Results: Within group comparisons between baseline and follow-up indicated no significant improvements in falls efficacy, however, the difference for the conventional exercise group approached statistical significance (baseline 8.9 to follow-up 9.3; P = 0.058). Within group comparisons of mean difference MFES scores showed a significant difference between the conventional exercise group and the control group (conventional exercise group 0.4 vs control group −0.6; P < 0.05). Conclusion: Given the lack of significant improvements in falls efficacy found for any of the groups, it cannot be concluded whether a conventional or a holistic exercise intervention is the best approach for improving falls efficacy. It is possible that the characteristics of the exercise interventions including specificity, intensity, frequency and duration need to be manipulated if the purpose is to bring about improvements in falls efficacy.
Resumo:
Dancers investigate ever-expanding relationships to embodiment through the variety of unique choreographic signatures that are continually erupting in professional practice. They live fragmented lineages that are interrupted and redirected as they traverse between various projects led by different choreographers or the same choreographer pursuing different creative goals. As contemporary dance continues to reconceive ways of moving, the dominant lineages of dance training are less useful as reference points through which dancers can recalibrate bodily activity and thus rebalance. In this chapter, I examine the impulse towards fragmentation in contemporary dance and explore how moments of agency for dancers might arise and be seized within the complexities of this environment. These issues are discussed in relation to my encounter with a bodywork therapy of Japanese origin, Amatsu, which I studied throughout 2012, and through the teaching principles of Gill Clarke as illuminated through the Minding Motion project, which explored Clarke’s pedagogy for Tanzplan, Germany 2010 (Diehl and Lampert, 2011). Moments from performance and bodywork practice are offered as examples throughout the chapter.
Resumo:
Identifying genetic variants influencing human brain structures may reveal new biological mechanisms underlying cognition and neuropsychiatric illness. The volume of the hippocampus is a biomarker of incipient Alzheimer's disease and is reduced in schizophrenia, major depression and mesial temporal lobe epilepsy. Whereas many brain imaging phenotypes are highly heritable, identifying and replicating genetic influences has been difficult, as small effects and the high costs of magnetic resonance imaging (MRI) have led to underpowered studies. Here we report genome-wide association meta-analyses and replication for mean bilateral hippocampal, total brain and intracranial volumes from a large multinational consortium. The intergenic variant rs7294919 was associated with hippocampal volume (12q24.22; N = 21,151; P = 6.70 × 10 -16) and the expression levels of the positional candidate gene TESC in brain tissue. Additionally, rs10784502, located within HMGA2, was associated with intracranial volume (12q14.3; N = 15,782; P = 1.12 × 10 -12). We also identified a suggestive association with total brain volume at rs10494373 within DDR2 (1q23.3; N = 6,500; P = 5.81 × 10 -7).
Resumo:
Alternative dispute resolution (ADR) methods, such as arbitration, are often used instead of litigation to resolve construction disputes, as industry folklore considers litigation overly expensive and time-consuming. But is this actually the case? Do the people most involved in construction dispute resolution agree? What are the real advantages and disadvantages of using litigation or ADR? When, if ever, is litigation the most appropriate way of resolving construction disputes? To answer these questions, this paper first provides a review of the literature on the use of litigation and ADR for construction dispute resolution. This is followed by the results of a survey of construction and legal personnel with moderate to extensive experience of dispute resolution in the Australian South-East Queensland construction industry. The main results of this are that, in addition to litigation being more expensive in money and time than ADR methods, the nature of the existing relationship between the parties has an important effect on the resolution process, what happens after an unsuccessful ADR and, if adversarial, is more likely to lead to litigation. The results are then validated and verified by one of the most experienced practitioners in claims and disputes in the whole of Australia.
Resumo:
Living cells are the functional unit of organs that controls reactions to their exterior. However, the mechanics of living cells can be difficult to characterize due to the crypticity of their microscale structures and associated dynamic cellular processes. Fortunately, multiscale modelling provides a powerful simulation tool that can be used to study the mechanical properties of these soft hierarchical, biological systems. This paper reviews recent developments in hierarchical multiscale modeling technique that aimed at understanding cytoskeleton mechanics. Discussions are expanded with respects to cytoskeletal components including: intermediate filaments, microtubules and microfilament networks. The mechanical performance of difference cytoskeleton components are discussed with respect to their structural and material properties. Explicit granular simulation methods are adopted with different coarse-grained strategies for these cytoskeleton components and the simulation details are introduced in this review.
Resumo:
Chlamydial infections of fish are emerging as an important cause of disease in new and established aquaculture industries. To date, epitheliocystis, a skin and gill disease associated with infection by these obligate intracellular pathogens, has been described in over 90 fish species, including hosts from marine and fresh water environments. Aided by advances in molecular detection and typing, recent years have seen an explosion in the description of these epitheliocystis-related chlamydial pathogens of fish, significantly broadening our knowledge of the genetic diversity of the order Chlamydiales. Remarkably, in most cases, it seems that each new piscine host studied has revealed the presence of a phylogenetically unique and novel chlamydial pathogen, providing researchers with a fascinating opportunity to understand the origin, evolution and adaptation of their traditional terrestrial chlamydial relatives. Despite the advances in this area, much still needs to be learnt about the epidemiology of chlamydial infections in fish if these pathogens are to be controlled in farmed environments. The lack of in vitro methods for culturing of chlamydial pathogens of fish is a major hindrance to this field. This review provides an update on our current knowledge of the taxonomy and diversity of chlamydial pathogens of fish, discusses the impact of these infections on the health, and highlights further areas of research required to understand the biology and epidemiology of this important emerging group of fish pathogens of aquaculture species.
Resumo:
Background Schizophrenia is associated with lower pre-morbid intelligence (IQ) in addition to (pre-morbid) cognitive decline. Both schizophrenia and IQ are highly heritable traits. Therefore, we hypothesized that genetic variants associated with schizophrenia, including copy number variants (CNVs) and a polygenic schizophrenia (risk) score (PSS), may influence intelligence. Method IQ was estimated with the Wechsler Adult Intelligence Scale (WAIS). CNVs were determined from single nucleotide polymorphism (SNP) data using the QuantiSNP and PennCNV algorithms. For the PSS, odds ratios for genome-wide SNP data were calculated in a sample collected by the Psychiatric Genome-Wide Association Study (GWAS) Consortium (8690 schizophrenia patients and 11 831 controls). These were used to calculate individual PSSs in our independent sample of 350 schizophrenia patients and 322 healthy controls. Results Although significantly more genes were disrupted by deletions in schizophrenia patients compared to controls (p = 0.009), there was no effect of CNV measures on IQ. The PSS was associated with disease status (R 2 = 0.055, p = 2.1 × 10 -7) and with IQ in the entire sample (R 2 = 0.018, p = 0.0008) but the effect on IQ disappeared after correction for disease status. Conclusions Our data suggest that rare and common schizophrenia-associated variants do not explain the variation in IQ in healthy subjects or in schizophrenia patients. Thus, reductions in IQ in schizophrenia patients may be secondary to other processes related to schizophrenia risk. © Cambridge University Press 2013.
Resumo:
Schizophrenia is an idiopathic mental disorder with a heritable component and a substantial public health impact. We conducted a multi-stage genome-wide association study (GWAS) for schizophrenia beginning with a Swedish national sample (5,001 cases and 6,243 controls) followed by meta-Analysis with previous schizophrenia GWAS (8,832 cases and 12,067 controls) and finally by replication of SNPs in 168 genomic regions in independent samples (7,413 cases, 19,762 controls and 581 parent-offspring trios). We identified 22 loci associated at genome-wide significance; 13 of these are new, and 1 was previously implicated in bipolar disorder. Examination of candidate genes at these loci suggests the involvement of neuronal calcium signaling. We estimate that 8,300 independent, mostly common SNPs (95% credible interval of 6,300-10,200 SNPs) contribute to risk for schizophrenia and that these collectively account for at least 32% of the variance in liability. Common genetic variation has an important role in the etiology of schizophrenia, and larger studies will allow more detailed understanding of this disorder.