108 research outputs found
Evolutionary relationships among barley and <i>Arabidopsis</i> core circadian clock and clock-associated genes
The circadian clock regulates a multitude of plant developmental and metabolic processes. In crop species, it contributes significantly to plant performance and productivity and to the adaptation and geographical range over which crops can be grown. To understand the clock in barley and how it relates to the components in the Arabidopsis thaliana clock, we have performed a systematic analysis of core circadian clock and clock-associated genes in barley, Arabidopsis and another eight species including tomato, potato, a range of monocotyledonous species and the moss, Physcomitrella patens. We have identified orthologues and paralogues of Arabidopsis genes which are conserved in all species, monocot/dicot differences, species-specific differences and variation in gene copy number (e.g. gene duplications among the various species). We propose that the common ancestor of barley and Arabidopsis had two-thirds of the key clock components identified in Arabidopsis prior to the separation of the monocot/dicot groups. After this separation, multiple independent gene duplication events took place in both monocot and dicot ancestors. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00239-015-9665-0) contains supplementary material, which is available to authorized users
High morbid-mortability and reduced level of osteoporosis diagnosis among elderly people who had hip fractures in São Paulo City
OBJECTIVE: To know the morbid-mortality following an osteoporotic hip fracture in elderly patients living in São Paulo. PATIENTS AND METHODS: This study evaluated prospectively all patient over 60 years admitted in 2 school-hospitals in the city of São Paulo in a following 6-month period due to a osteoporotic proximal femur fracture. All of them filled up the Health Assessment Questionnaire (HAQ) and had their chart reviewed. After 6 months they were re-interviewed. Linear regression analysis was utilized to determine the factors related to functional ability. RESULTS: 56 patients were included (mean age 80.7 ± 7.9 years old, 80.4% females). After the 6-month follow up the mortality rate was 23.2%. Only 30% of the patients returned to their previous activities, and 11.6% became totally dependent. Factors related to worse functional ability after fracture were HAQ before fracture, institutionalization after fracture and age (r² 0.482). The diagnosis of osteoporosis was informed only by 13.9% of them, and just 11.6% received any treatment for that. CONCLUSION: Our results showed the great impact of these fractures on mortality and in the functional ability of these patients. Nevertheless, many of our physicians do not inform the patients about the diagnosis of osteoporosis and, consequently, the treatment of this condition is jeopardized.As fraturas osteoporóticas de fêmur proximal trazem graves conseqüências quanto à morbimortalidade e à qualidade de vida, mas desconhece-se este impacto no Brasil. OBJETIVO: Conhecer a morbimortalidade decorrente deste tipo de fraturas em idosos na cidade de São Paulo. MÉTODOS: Foram incluídos todos os pacientes com mais de 60 anos internados por fraturas de fêmur proximal durante seis meses, em dois hospitais de São Paulo. Os pacientes preencheram o questionário de capacidade funcional (HAQ), tiveram seu prontuário examinado e foram reavaliados após seis meses. Utilizou-se a análise de regressão linear para determinar os fatores relacionados à capacidade funcional. RESULTADOS: Cinqüenta e seis pacientes foram incluídos no estudo (80,7 ± 7,9 anos; 80,4% mulheres). A mortalidade em seis meses foi de 23,2%. Apenas 30% retornaram plenamente às suas atividades prévias e 11,6% tornaram-se completamente dependentes. Os fatores que mais bem conseguiram prever pior capacidade funcional após a fratura foram HAQ pré-fratura, institucionalização pós-fratura e idade (r² 0,482). Somente 13,9% receberam o diagnóstico de osteoporose e 11,6% iniciaram algum tratamento. CONCLUSÕES: Os resultados do presente estudo demonstram o impacto deste tipo de fraturas sobre a mortalidade e a capacidade funcional. Entretanto, a falha médica no diagnóstico e na orientação de tratamento da osteoporose permanece elevada.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaSanta Casa de Misericórdia de São Paulo Departamento de OrtopediaUNIFESP-EPM EPMUNIFESP, EPM, EPMSciEL
A New Mechanistic Scenario for the Origin and Evolution of Vertebrate Cartilage
The appearance of cellular cartilage was a defining event in vertebrate evolution because it made possible the physical expansion of the vertebrate “new head”. Despite its central role in vertebrate evolution, the origin of cellular cartilage has been difficult to understand. This is largely due to a lack of informative evolutionary intermediates linking vertebrate cellular cartilage to the acellular cartilage of invertebrate chordates. The basal jawless vertebrate, lamprey, has long been considered key to understanding the evolution of vertebrate cartilage. However, histological analyses of the lamprey head skeleton suggest it is composed of modern cellular cartilage and a putatively unrelated connective tissue called mucocartilage, with no obvious transitional tissue. Here we take a molecular approach to better understand the evolutionary relationships between lamprey cellular cartilage, gnathostome cellular cartilage, and lamprey mucocartilage. We find that despite overt histological similarity, lamprey and gnathostome cellular cartilage utilize divergent gene regulatory networks (GRNs). While the gnathostome cellular cartilage GRN broadly incorporates Runx, Barx, and Alx transcription factors, lamprey cellular cartilage does not express Runx or Barx, and only deploys Alx genes in certain regions. Furthermore, we find that lamprey mucocartilage, despite its distinctive mesenchymal morphology, deploys every component of the gnathostome cartilage GRN, albeit in different domains. Based on these findings, and previous work, we propose a stepwise model for the evolution of vertebrate cellular cartilage in which the appearance of a generic neural crest-derived skeletal tissue was followed by a phase of skeletal tissue diversification in early agnathans. In the gnathostome lineage, a single type of rigid cellular cartilage became dominant, replacing other skeletal tissues and evolving via gene cooption to become the definitive cellular cartilage of modern jawed vertebrates
Transforming Growth Factor: β Signaling Is Essential for Limb Regeneration in Axolotls
Axolotls (urodele amphibians) have the unique ability, among vertebrates, to perfectly regenerate many parts of their body including limbs, tail, jaw and spinal cord following injury or amputation. The axolotl limb is the most widely used structure as an experimental model to study tissue regeneration. The process is well characterized, requiring multiple cellular and molecular mechanisms. The preparation phase represents the first part of the regeneration process which includes wound healing, cellular migration, dedifferentiation and proliferation. The redevelopment phase represents the second part when dedifferentiated cells stop proliferating and redifferentiate to give rise to all missing structures. In the axolotl, when a limb is amputated, the missing or wounded part is regenerated perfectly without scar formation between the stump and the regenerated structure. Multiple authors have recently highlighted the similarities between the early phases of mammalian wound healing and urodele limb regeneration. In mammals, one very important family of growth factors implicated in the control of almost all aspects of wound healing is the transforming growth factor-beta family (TGF-β). In the present study, the full length sequence of the axolotl TGF-β1 cDNA was isolated. The spatio-temporal expression pattern of TGF-β1 in regenerating limbs shows that this gene is up-regulated during the preparation phase of regeneration. Our results also demonstrate the presence of multiple components of the TGF-β signaling machinery in axolotl cells. By using a specific pharmacological inhibitor of TGF-β type I receptor, SB-431542, we show that TGF-β signaling is required for axolotl limb regeneration. Treatment of regenerating limbs with SB-431542 reveals that cellular proliferation during limb regeneration as well as the expression of genes directly dependent on TGF-β signaling are down-regulated. These data directly implicate TGF-β signaling in the initiation and control of the regeneration process in axolotls
Determination of the ratio of b-quark fragmentation fractions fs/fd in pp collisions at √s = 7 TeV with the ATLAS Detector
With an integrated luminosity of 2.47 fb−1 recorded by the ATLAS experiment at the LHC, the exclusive decays B 0s→J/ψϕ and B0d→J/ψK*0 of B mesons produced in pp collisions at √s=7 TeV are used to determine the ratio of fragmentation fractions fs/fd. From the observed B0s→J/ψϕ and B0d→J/ψK*0 yields, the quantity (fs/fd)[B(B0s→J/ψϕ)/B(B 0d→J/ψK*0)] is measured to be 0.199±0.004(stat)±0.008(syst). Using a recent theory prediction for [B(B0s→J/ψϕ)/B(B0d→J/ψK*0)] yields (fs/fd)=0.240±0.004(stat)±0.010(syst)±0.017(th). This result is based on a new approach that provides a significant improvement of the world average
Inhibition of protein ubiquitination by paraquat and 1-methyl-4-phenylpyridinium impairs ubiquitin-dependent protein degradation pathways
Intracytoplasmic inclusions of protein aggregates in dopaminergic cells (Lewy bodies) are the pathological hallmark of Parkinson’s disease (PD). Ubiquitin (Ub), alpha [α]-synuclein, p62/sequestosome 1 and oxidized proteins are major components of Lewy bodies. However, the mechanisms involved in the impairment of misfolded/oxidized protein degradation pathways in PD are still unclear. PD is linked to mitochondrial dysfunction and environmental pesticide exposure. In this work, we evaluated the effect of the pesticide paraquat (PQ) and the mitochondrial toxin 1-methyl-4-phenylpyridinium (MPP+) on Ub-dependent protein degradation pathways. No increase in the accumulation of Ub-bound proteins or aggregates was observed in dopaminergic cells (SK-N-SH) treated with PQ or MPP+, or in mice chronically exposed to PQ. PQ decreased Ub protein content, but not its mRNA transcription. Protein synthesis inhibition with cycloheximide depleted Ub levels and potentiated PQ–induced cell death. Inhibition of proteasomal activity by PQ was found to be a late event in cell death progression, and had no effect on either the toxicity of MPP+ or PQ, or the accumulation of oxidized sulfenylated, sulfonylated (DJ-1/PARK7 and peroxiredoxins) and carbonylated proteins induced by PQ. PQ- and MPP+-induced Ub protein depletion prompted the dimerization/inactivation of the Ub-binding protein p62 that regulates the clearance of ubiquitinated proteins by autophagic. We confirmed that PQ and MPP+ impaired autophagy flux, and that the blockage of autophagy by the overexpression of a dominant-negative form of the autophagy protein 5 (dnAtg5) stimulated their toxicity, but there was no additional effect upon inhibition of the proteasome. PQ induced an increase in the accumulation of α-synuclein in dopaminergic cells and membrane associated foci in yeast cells. Our results demonstrate that inhibition of protein ubiquitination by PQ and MPP+ is involved in the dysfunction of Ub-dependent protein degradation pathways
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