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61.
Ano Bom AP Rangel LP Costa DC de Oliveira GA Sanches D Braga CA Gava LM Ramos CH Cepeda AO Stumbo AC De Moura Gallo CV Cordeiro Y Silva JL 《The Journal of biological chemistry》2012,287(33):28152-28162
Over 50% of all human cancers lose p53 function. To evaluate the role of aggregation in cancer, we asked whether wild-type (WT) p53 and the hot-spot mutant R248Q could aggregate as amyloids under physiological conditions and whether the mutant could seed aggregation of the wild-type form. The central domains (p53C) of both constructs aggregated into a mixture of oligomers and fibrils. R248Q had a greater tendency to aggregate than WT p53. Full-length p53 aggregated into amyloid-like species that bound thioflavin T. The amyloid nature of the aggregates was demonstrated using x-ray diffraction, electron microscopy, FTIR, dynamic light scattering, cell viabilility assay, and anti-amyloid immunoassay. The x-ray diffraction pattern of the fibrillar aggregates was consistent with the typical conformation of cross β-sheet amyloid fibers with reflexions of 4.7 Å and 10 Å. A seed of R248Q p53C amyloid oligomers and fibrils accelerated the aggregation of WT p53C, a behavior typical of a prion. The R248Q mutant co-localized with amyloid-like species in a breast cancer sample, which further supported its prion-like effect. A tumor cell line containing mutant p53 also revealed massive aggregation of p53 in the nucleus. We conclude that aggregation of p53 into a mixture of oligomers and fibrils sequestrates the native protein into an inactive conformation that is typical of a prionoid. This prion-like behavior of oncogenic p53 mutants provides an explanation for the negative dominance effect and may serve as a potential target for cancer therapy. 相似文献
62.
Jose Alexandre F. Diniz‐Filho Luis Mauricio Bini Thiago Fernando Rangel Ignacio Morales‐Castilla Miguel Á. Olalla‐Tárraga Miguel Á. Rodríguez Bradford A. Hawkins 《Ecography》2012,35(3):239-249
Among the statistical methods available to control for phylogenetic autocorrelation in ecological data, those based on eigenfunction analysis of the phylogenetic distance matrix among the species are becoming increasingly important tools. Here, we evaluate a range of criteria to select eigenvectors extracted from a phylogenetic distance matrix (using phylogenetic eigenvector regression, PVR) that can be used to measure the level of phylogenetic signal in ecological data and to study correlated evolution. We used a principal coordinate analysis to represent the phylogenetic relationships among 209 species of Carnivora by a series of eigenvectors, which were then used to model log‐transformed body size. We first conducted a series of PVRs in which we increased the number of eigenvectors from 1 to 70, following the sequence of their associated eigenvalues. Second, we also investigated three non‐sequential approaches based on the selection of 1) eigenvectors significantly correlated with body size, 2) eigenvectors selected by a standard stepwise algorithm, and 3) the combination of eigenvectors that minimizes the residual phylogenetic autocorrelation. We mapped the mean specific component of body size to evaluate how these selection criteria affect the interpretation of non‐phylogenetic signal in Bergmann's rule. For comparison, the same patterns were analyzed using autoregressive model (ARM) and phylogenetic generalized least‐squares (PGLS). Despite the robustness of PVR to the specific approaches used to select eigenvectors, using a relatively small number of eigenvectors may be insufficient to control phylogenetic autocorrelation, leading to flawed conclusions about patterns and processes. The method that minimizes residual autocorrelation seems to be the best choice according to different criteria. Thus, our analyses show that, when the best criterion is used to control phylogenetic structure, PVR can be a valuable tool for testing hypotheses related to heritability at the species level, phylogenetic niche conservatism and correlated evolution between ecological traits. 相似文献
63.
Varani AM Monteiro-Vitorello CB de Almeida LG Souza RC Cunha OL Lima WC Civerolo E Van Sluys MA Vasconcelos AT 《Genetics and molecular biology》2012,35(1):149-152
The Xylella fastidiosa comparative genomic database is a scientific resource with the aim to provide a user-friendly interface for accessing high-quality manually curated genomic annotation and comparative sequence analysis, as well as for identifying and mapping prophage-like elements, a marked feature of Xylella genomes. Here we describe a database and tools for exploring the biology of this important plant pathogen. The hallmarks of this database are the high quality genomic annotation, the functional and comparative genomic analysis and the identification and mapping of prophage-like elements. It is available from web site http://www.xylella.lncc.br. 相似文献
64.
Santos PL Costa RV Braz JM Santos LF Batista AC Vasconcelos CR Rangel MR Ribeiro de Jesus A de Moura TR Leopoldo PT Almeida RP 《Nitric oxide》2012,27(1):67-71
Nitric oxide (NO) plays an important role as a leishmanicidal agent in murine macrophages. NO resistant Escherichia coli and Mycobacterium tuberculosis have been associated with poor outcomes of their resulting diseases. NO resistant Leishmania braziliensis has also been identified and exacerbates the clinical course of human leishmaniasis. We report, for the first time, natural resistance of Leishmania chagasi promastigotes to NO. These parasites were isolated from humans and dogs with visceral leishmaniasis. We also demonstrate that this resistance profile was associated with a greater survival capacity and a greater parasite burden in murine macrophages, independent of activation and after activation by IFN-γ and LPS. 相似文献
65.
Fernandes EK Rangel DE Moraes AM Bittencourt VR Roberts DW 《Journal of invertebrate pathology》2008,98(1):69-78
Heat and cold are environmental abiotic factors that restrict the use of entomopathogenic fungi as agents for biological control of insects. The thermotolerance and cold activity of 60 entomopathogenic fungal isolates, including five species of Beauveria and one isolate of Engyodontium albus (=Beauveria alba) were examined as to tolerance of temperatures that might be encountered during field use. In addition, cold activity of eight Metarhizium spp. isolates was evaluated. The isolates were from various geographic regions, arthropod hosts or substrates. High variability in conidial thermotolerance was found among the Beauveria spp. isolates after exposure to 45 °C for 2 h, as evidenced by low (0-20%), medium (20-60%), or high germination (60-80%). The thermal death point (0% germination) for three rather thermotolerant B. bassiana isolates (CG 138, GHA and ARSEF 252) was 46 °C for 6 h. At low temperatures (5 °C), with few exceptions (e.g. CG 66, UFPE 479, CG 227, CG 02), most of the B. bassiana isolates germinated well (ca. 100%). On the other hand, only one isolate of Metarhizium sp. was cold-active (i.e. ARSEF 4343 from Macquarie Island, 54.4°S, Australia). This probably is a M. frigidum isolate. The E. albus isolate (UFPE 3138) was the most susceptible isolate to both heat and cold stress. Isolates ARSEF 252 and GHA of B. bassiana, on the other hand, presented exceptionally high thermotolerance and cold activity. Some isolates with high cold activity, however, were thermosensitive (e.g. ARSEF 1682) and others with high thermotolerance had low cold activity (e.g. CG 227). An attempt to correlate the latitude of origin with thermotolerance or cold activity indicated that B. bassiana isolates from higher latitudes were more cold-active than isolates from nearer the equator, but there was not a similar correlation for heat. 相似文献
66.
A simulated continuous wave electron paramagnetic resonance spectrum of a nitroxide spin label can be obtained from the Fourier transform of a free induction decay. It has been previously shown that the free induction decay can be calculated by solving the time-dependent stochastic Liouville equation for a set of Brownian trajectories defining the rotational dynamics of the label. In this work, a quaternion-based Monte Carlo algorithm has been developed to generate Brownian trajectories describing the global rotational diffusion of a spin-labeled protein. Also, molecular dynamics simulations of two spin-labeled mutants of T4 lysozyme, T4L F153R1, and T4L K65R1 have been used to generate trajectories describing the internal dynamics of the protein and the local dynamics of the spin-label side chain. Trajectories from the molecular dynamics simulations combined with trajectories describing the global rotational diffusion of the protein are used to account for all of the dynamics of a spin-labeled protein. Spectra calculated from these combined trajectories correspond well to the experimental spectra for the buried site T4L F153R1 and the helix surface site T4L K65R1. This work provides a framework to further explore the modeling of the dynamics of the spin-label side chain in the wide variety of labeling environments encountered in site-directed spin labeling studies. 相似文献
67.
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69.
Maurício Luiz Vilela Daniela de Pita-Pereira Carina Graser Azevedo Rodrigo Espíndola Godoy Constan?a Britto Elizabeth Ferreira Rangel 《Memórias do Instituto Oswaldo Cruz》2013,108(5):578-585
Phlebotomine sandflies were captured in rural settlement and periurban
areas of the municipality of Guaraí in the state of Tocantins (TO), an endemic
area of American cutaneous leishmaniasis (ACL). Forty-three phlebotomine species
were identified, nine of which have already been recognised as ACL vectors.
Eleven species were recorded for the first time in TO. Nyssomyia
whitmani was the most abundant species, followed by
Evandromyia bourrouli, Nyssomyia antunesi
and Psychodopygus complexus. The Shannon-Wiener diversity index
and the evenness index were higher in the rural settlement area than in the
periurban area. The evaluation of different ecotopes within the rural area
showed the highest frequencies of Ev. bourrouli and Ny.
antunesi in chicken coops, whereas Ny. whitmani
predominated in this ecotope in the periurban area. In the rural settlement
area, Ev. bourrouli was the most frequently captured species in
automatic light traps and Ps. complexus was the most prevalent
in Shannon trap captures. The rural settlement environment exhibited greater
phlebotomine biodiversity than the periurban area. Ps.
complexus and Psychodopygus ayrozai naturally
infected with Leishmania (Viannia) braziliensis were
identified. The data identified Ny. whitmani as a potential ACL
vector in the periurban area, whereas Ps. complexus was more
prevalent in the rural environment associated with settlements. 相似文献
70.