743 research outputs found
Amphibia, Hylidae, <i>Bokermannohyla sazimai</i> (Cardoso and Andrade 1982): distribution extension
Tau mutation S356T in the three repeat isoform leads to microtubule dysfunction and promotes prion-like seeded aggregation
Tauopathies are a group of neurodegenerative diseases, which include frontotemporal dementia (FTD) and Alzheimerâs disease (AD), broadly defined by the development of tau brain aggregates. Both missense and splicing tau mutations can directly cause early onset FTD. Tau protein is a microtubule-associated protein that stabilizes and regulates microtubules, but this function can be disrupted in disease states. One contributing factor is the balance of different tau isoforms, which can be categorized into either three repeat (3R) or four repeat (4R) isoforms based on the number of microtubule-binding repeats that are expressed. Imbalance of 3R and 4R isoforms in either direction can cause FTD and neurodegeneration. There is also increasing evidence that 3R tauopathies such as Pickâs disease form tau aggregates predominantly comprised of 3R isoforms and these can present differently from 4R and mixed 3R/4R tauopathies. In this study, multiple mutations in 3R tau were assessed for MT binding properties and prion-like aggregation propensity. Different missense tau mutations showed varying effects on MT binding depending on molecular location and properties. Of the mutations that were surveyed, S356T tau is uniquely capable of prion-like seeded aggregation and forms extensive Thioflavin positive aggregates. This unique prion-like tau strain will be useful to model 3R tau aggregation and will contribute to the understanding of diverse presentations of different tauopathies
The A alpha mating locus of Schizophyllum commune encodes two dissimilar multiallelic homeodomain proteins.
Soil respiration in a northeastern US temperate forest: a 22âyear synthesis
To better understand how forest management, phenology, vegetation type, and actual and simulated climatic change affect seasonal and interâannual variations in soil respiration (Rs), we analyzed more than 100,000 individual measurements of soil respiration from 23 studies conducted over 22 years at the Harvard Forest in Petersham, Massachusetts, USA. We also used 24 siteâyears of eddyâcovariance measurements from two Harvard Forest sites to examine the relationship between soil and ecosystem respiration (Re).
Rs was highly variable at all spatial (respiration collar to forest stand) and temporal (minutes to years) scales of measurement. The response of Rs to experimental manipulations mimicking aspects of global change or aimed at partitioning Rs into component fluxes ranged from â70% to +52%. The response appears to arise from variations in substrate availability induced by changes in the size of soil C pools and of belowground C fluxes or in environmental conditions. In some cases (e.g., logging, warming), the effect of experimental manipulations on Rs was transient, but in other cases the time series were not long enough to rule out longâterm changes in respiration rates. Interâannual variations in weather and phenology induced variation among annual Rs estimates of a magnitude similar to that of other drivers of global change (i.e., invasive insects, forest management practices, N deposition). At both eddyâcovariance sites, aboveground respiration dominated Re early in the growing season, whereas belowground respiration dominated later. Unusual aboveground respiration patternsâhigh apparent rates of respiration during winter and very low rates in midâtoâlate summerâat the Environmental Measurement Site suggest either bias in Rs and Re estimates caused by differences in the spatial scale of processes influencing fluxes, or that additional research on the hardâtoâmeasure fluxes (e.g., wintertime Rs, unaccounted losses of CO2 from eddy covariance sites), daytime and nighttime canopy respiration and its impacts on estimates of Re, and independent measurements of flux partitioning (e.g., aboveground plant respiration, isotopic partitioning) may yield insight into the unusually high and low fluxes. Overall, however, this dataârich analysis identifies important seasonal and experimental variations in Rs and Re and in the partitioning of Re aboveâ vs. belowground
Soil respiration in a northeastern US temperate forest: a 22âyear synthesis
To better understand how forest management, phenology, vegetation type, and actual and simulated climatic change affect seasonal and interâannual variations in soil respiration (Rs), we analyzed more than 100,000 individual measurements of soil respiration from 23 studies conducted over 22 years at the Harvard Forest in Petersham, Massachusetts, USA. We also used 24 siteâyears of eddyâcovariance measurements from two Harvard Forest sites to examine the relationship between soil and ecosystem respiration (Re).
Rs was highly variable at all spatial (respiration collar to forest stand) and temporal (minutes to years) scales of measurement. The response of Rs to experimental manipulations mimicking aspects of global change or aimed at partitioning Rs into component fluxes ranged from â70% to +52%. The response appears to arise from variations in substrate availability induced by changes in the size of soil C pools and of belowground C fluxes or in environmental conditions. In some cases (e.g., logging, warming), the effect of experimental manipulations on Rs was transient, but in other cases the time series were not long enough to rule out longâterm changes in respiration rates. Interâannual variations in weather and phenology induced variation among annual Rs estimates of a magnitude similar to that of other drivers of global change (i.e., invasive insects, forest management practices, N deposition). At both eddyâcovariance sites, aboveground respiration dominated Re early in the growing season, whereas belowground respiration dominated later. Unusual aboveground respiration patternsâhigh apparent rates of respiration during winter and very low rates in midâtoâlate summerâat the Environmental Measurement Site suggest either bias in Rs and Re estimates caused by differences in the spatial scale of processes influencing fluxes, or that additional research on the hardâtoâmeasure fluxes (e.g., wintertime Rs, unaccounted losses of CO2 from eddy covariance sites), daytime and nighttime canopy respiration and its impacts on estimates of Re, and independent measurements of flux partitioning (e.g., aboveground plant respiration, isotopic partitioning) may yield insight into the unusually high and low fluxes. Overall, however, this dataârich analysis identifies important seasonal and experimental variations in Rs and Re and in the partitioning of Re aboveâ vs. belowground
DivisĂŁo Racional de Terras: um Estudo de Caso em Londrina, PR
At present, the lands fragmentation in little parts for family interests is done by the try and mistakes method, in which, the
technician try to delimit the areas in similar dimensions and proportions for each interested. They do it based in theier perception and
experience. The aim of this paper was to define a conduct line for the treatment of questions referent to the lands division and verify if
the fragmentation proposed in a rural property at Londrina, ParanĂĄ state, in Brazil, was fair, considering as a critery, the land suitability.
The rational land division was done based at the land use capacity system. It was applied a relative value to each area portion in
agreement with its capability. As the equivalent area value of the each fragment consider the land quality, the final results should be
similar. However, there is a large diversity of territories. The datas show that the ten resultant areas of the division proposed for the
rural imovel present variated proportions of the diferents classes. Like this, with the division proposed by the expert, it was obtained
area fragments very diferents related to the land qualit
Mapeamento digital de classes de solos: caracterĂsticas da abordagem brasileira.
O solo Ă© cada vez mais reconhecido como tendo um importante papel nos ecossistemas, assim como para a produção de alimentos e regulação do clima global. Por esse motivo, a demanda por informaçÔes relevantes e atualizadas em solos Ă© crescente. Pesquisadores em ciĂȘncia do solo estĂŁo sendo demandados a gerar informaçÔes em diferentes resoluçÔes espaciais e com qualidade associada dentro do que estĂĄ sendo chamado de Mapeamento Digital de Solos (MDS). Devido ao crescente nĂșmero de trabalhos relacionados ao MDS, faz-se necessĂĄrio reunir e discutir as principais caracterĂsticas dos estudos relacionados ao mapeamento digital de classes de solos no Brasil, o que irĂĄ possibilitar uma perspectiva mais ampla dos caminhos, alĂ©m de nortear trabalhos e demandas futuras. O mapeamento de classes de solos empregando tĂ©cnicas de MDS Ă© recente no paĂs, com a primeira publicação em 2006. Entre as funçÔes preditivas utilizadas, predomina o emprego da tĂ©cnica de regressĂ”es logĂsticas. O fator de formação relevo foi empregado na totalidade dos estudos revisados. Quanto Ă avaliação da qualidade dos modelos preditivos, o emprego da matriz de erros e do Ăndice kappa tĂȘm sido os procedimentos mais usuais. A consolidação dessa abordagem automatizada como ferramenta auxiliar ao mapeamento convencional passa pelo treinamento dos jovens pedĂłlogos para a utilização de tecnologias da geoinformação e de ferramentas quantitativas dos aspectos de variabilidade do solo
Site-specific perturbations of alpha-synuclein fibril structure by the Parkinson's disease associated mutations A53T and E46K.
PMCID: PMC3591419This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Parkinson's disease (PD) is pathologically characterized by the presence of Lewy bodies (LBs) in dopaminergic neurons of the substantia nigra. These intracellular inclusions are largely composed of misfolded α-synuclein (AS), a neuronal protein that is abundant in the vertebrate brain. Point mutations in AS are associated with rare, early-onset forms of PD, although aggregation of the wild-type (WT) protein is observed in the more common sporadic forms of the disease. Here, we employed multidimensional solid-state NMR experiments to assess A53T and E46K mutant fibrils, in comparison to our recent description of WT AS fibrils. We made de novo chemical shift assignments for the mutants, and used these chemical shifts to empirically determine secondary structures. We observe significant perturbations in secondary structure throughout the fibril core for the E46K fibril, while the A53T fibril exhibits more localized perturbations near the mutation site. Overall, these results demonstrate that the secondary structure of A53T has some small differences from the WT and the secondary structure of E46K has significant differences, which may alter the overall structural arrangement of the fibrils
Avaliação da qualidade de um fertilizante produzido por compostagem conjunta de materiais orgĂąnicos e rochas moĂdas.
Ao longo de milhares de anos, diferentes povos realizaram uma agricultura baseada no manejo dos materiais disponĂveis nas propriedades rurais. Uma das formas para se atingir essa condiçãoĂ© a produção e uso de compostos orgĂąnicos. Este trabalho tevecomo objetivo avaliar a qualidade docompostoorgĂąnico produzido com fontes de nutrientesdeorigem regionalem uma propriedade rural.As matĂ©rias-primas utilizadas para a produção do fertilizanteforam cama de bovino, serragem, casca de cafĂ© e pĂł de rochas. A compostagem foi iniciada com relação C:N entre 25 e 35 e terminada com relação C:N menor que 15. A realização da aeração do condicionadorfoi feita com um compostador e, a umidificação, com um tanque pipa.AsanĂĄlisesquĂmica, orgĂąnica, biolĂłgica e sanitĂĄria indicam que o processo de compostagem foi realizado de forma correta. Com isso, o composto exibiu a maioria das garantias mĂnimas para ser enquadrado como fertilizante orgĂąnico composto classe A, o que pode melhoraras condiçÔes fĂsicas, quĂmicas e biolĂłgicas do solo, aumentando a autonomia do agricultor e diminuindo sua dependĂȘncia dos combustĂveis fĂłsseis
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Soil Respiration in a Northeastern US Temperate Forest: A 22-Year Synthesis
To better understand how forest management, phenology, vegetation type, and actual and simulated climatic change affect seasonal and inter-annual variations in soil respiration (R), we analyzed more than 100,000 individual measurements of soil respiration from 23 studies conducted over 22 years at the Harvard Forest in Petersham, Massachusetts, USA. We also used 24 site-years of eddy-covariance measurements from two Harvard Forest sites to examine the relationship between soil and ecosystem respiration (R).
R was highly variable at all spatial (respiration collar to forest stand) and temporal (minutes to years) scales of measurement. The response of R to experimental manipulations mimicking aspects of global change or aimed at partitioning R into component fluxes ranged from â70% to +52%. The response appears to arise from variations in substrate availability induced by changes in the size of soil C pools and of belowground C fluxes or in environmental conditions. In some cases (e.g., logging, warming), the effect of experimental manipulations on R was transient, but in other cases the time series were not long enough to rule out long-term changes in respiration rates. Inter-annual variations in weather and phenology induced variation among annual R estimates of a magnitude similar to that of other drivers of global change (i.e., invasive insects, forest management practices, N deposition). At both eddy-covariance sites, aboveground respiration dominated R early in the growing season, whereas belowground respiration dominated later. Unusual aboveground respiration patternsâhigh apparent rates of respiration during winter and very low rates in mid-to-late summerâat the Environmental Measurement Site suggest either bias in R and R estimates caused by differences in the spatial scale of processes influencing fluxes, or that additional research on the hard-to-measure fluxes (e.g., wintertime R, unaccounted losses of CO from eddy covariance sites), daytime and nighttime canopy respiration and its impacts on estimates of R, and independent measurements of flux partitioning (e.g., aboveground plant respiration, isotopic partitioning) may yield insight into the unusually high and low fluxes. Overall, however, this data-rich analysis identifies important seasonal and experimental variations in R and R and in the partitioning of R above- vs. belowground.Organismic and Evolutionary Biolog
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