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排序方式: 共有282条查询结果,搜索用时 140 毫秒
161.
Gustavo Torres de Souza Claudinéia Pereira Maranduba Camila Maurmann de Souza Danielle Luciana Aurora Soares do Amaral Francisco Carlos da Guia Rafaella de Souza Salom?o Zanette Jo?o Vitor Paes Rettore Natana Chaves Rabelo Lucas Mendes Nascimento ícaro Fran?a Navarro Pinto Júlia Boechat Farani Abrah?o Elias Hallack Neto Fernando de Sá Silva Carlos Magno da Costa Maranduba Angelo Atalla 《World journal of stem cells》2015,7(1):106-115
Despite the advances in the hematology field, blood transfusion-related iatrogenesis is still a major issue to be considered during such procedures due to blood antigenic incompatibility. This places pluripotent stem cells as a possible ally in the production of more suitable blood products. The present review article aims to provide a comprehensive summary of the state-of-theart concerning the differentiation of both embryonic stem cells and induced pluripotent stem cells to hematopoietic cell lines. Here, we review the most recently published protocols to achieve the production of blood cells for future application in hemotherapy, cancer therapy and basic research. 相似文献
162.
163.
It is well established that L-proline has several roles in the biology of trypanosomatids. In Trypanosoma cruzi, the etiological agent of Chagas'' disease, this amino acid is involved in energy metabolism, differentiation processes and resistance to osmotic stress. In this study, we analyzed the effects of interfering with L-proline metabolism on the viability and on other aspects of the T. cruzi life cycle using the proline analogue L- thiazolidine-4-carboxylic acid (T4C). The growth of epimastigotes was evaluated using different concentrations of T4C in standard culture conditions and at high temperature or acidic pH. We also evaluated possible interactions of this analogue with stress conditions such as those produced by nutrient starvation and oxidative stress. T4C showed a dose-response effect on epimastigote growth (IC50 = 0.89±0.02 mM at 28°C), and the inhibitory effect of this analogue was synergistic (p<0.05) with temperature (0.54±0.01 mM at 37°C). T4C significantly diminished parasite survival (p<0.05) in combination with nutrient starvation and oxidative stress conditions. Pre-incubation of the parasites with L-proline resulted in a protective effect against oxidative stress, but this was not seen in the presence of the drug. Finally, the trypomastigote bursting from infected mammalian cells was evaluated and found to be inhibited by up to 56% when cells were treated with non-toxic concentrations of T4C (between 1 and 10 mM). All these data together suggest that T4C could be an interesting therapeutic drug if combined with others that affect, for example, oxidative stress. The data also support the participation of proline metabolism in the resistance to oxidative stress. 相似文献
164.
We report a novel staining technique for human brain slices that distinguishes clearly gray from white matter. Previously described techniques using either Prussian blue (Berlin blue) or phthalocyanine dyes usually have included a hot phenol pretreatment to prevent white matter staining. The technique we describe here does not require hot phenol pretreatment and allows the use of brains stored for postmortem periods of one to two years prior to staining. Our technique involves staining with copper(II) phthalocyanine-tetrasulfonic acid tetrasodium salt 1% in water for 2 h followed by acetic acid treatment; this produces excellent blue staining of gray matter with little white matter staining. The stained brain slices are excellent for teaching human brain anatomy and/or pathology, or for research purposes. 相似文献
165.
166.
Simone Dell’Acqua Sofia R. Pauleta Patrícia M. Paes de Sousa Enrico Monzani Luigi Casella José J. G. Moura Isabel Moura 《Journal of biological inorganic chemistry》2010,15(6):967-976
The final step of bacterial denitrification, the two-electron reduction of N2O to N2, is catalyzed by a multi-copper enzyme named nitrous oxide reductase. The catalytic centre of this enzyme is a tetranuclear
copper site called CuZ, unique in biological systems. The in vitro reconstruction of the activity requires a slow activation
in the presence of the artificial electron donor, reduced methyl viologen, necessary to reduce CuZ from the resting non-active
state (1CuII/3CuI) to the fully reduced state (4CuI), in contrast to the turnover cycle, which is very fast. In the present work, the direct reaction of the activated form of
Pseudomonas nautica nitrous oxide reductase with stoichiometric amounts of N2O allowed the identification of a new reactive intermediate of the catalytic centre, CuZ°, in the turnover cycle, characterized
by an intense absorption band at 680 nm. Moreover, the first mediated electrochemical study of Ps. nautica nitrous oxide reductase with its physiological electron donor, cytochrome c-552, was performed. The intermolecular electron transfer was analysed by cyclic voltammetry, under catalytic conditions,
and a second-order rate constant of (5.5 ± 0.9) × 105 M−1 s−1 was determined. Both the reaction of stoichiometric amounts of substrate and the electrochemical studies show that the active
CuZ° species, generated in the absence of reductants, can rearrange to the resting non-active CuZ state. In this light, new
aspects of the catalytic and activation/inactivation mechanism of the enzyme are discussed. 相似文献
167.
María E. Peichoto Adriana F. Paes Leme Bianca A. Pauletti Isabel Correia Batista Stephen P. Mackessy Ofelia Acosta Marcelo L. Santoro 《Biochimica et Biophysica Acta - Proteins and Proteomics》2010,1804(9):1937-1942
Patagonfibrase is a 57.5-kDa hemorrhagic metalloproteinase isolated from the venom of Philodryas patagoniensis (Patagonia Green Racer), a South American rear-fanged snake. Herein we demonstrate that patagonfibrase undergoes autolysis at its pH optimum (7.5) and at 37 °C, primarily producing a ∼ 32.6 kDa fragment composed of disintegrin-like and cysteine-rich domains, as identified by mass spectrometry and N-terminal sequencing. The autolysis site for production of this fragment is similar to that observed for metalloproteinases from front-fanged Viperidae snake venoms. In the presence of Ca2+, patagonfibrase was only partially autolysed, giving rise mainly to one fragment of ∼ 52.2 kDa. In addition, calcium markedly enhanced the azocaseinolytic activity of patagonfibrase. Our findings contribute to the understanding of the structural and mechanistic bases of this family of metalloenzymes that are widely distributed among snake venoms, demonstrating that important post-translational modifications such as proteolysis can also contribute to the diversity and complexity of proteins found in rear-fanged snake venoms. 相似文献
168.
Church LD Filer AD Hidalgo E Howlett KA Thomas AM Rapecki S Scheel-Toellner D Buckley CD Raza K 《Arthritis research & therapy》2010,12(5):R184
Introduction
Th17 cells have been implicated in the pathogenesis of rheumatoid arthritis (RA). The aim of this study was to systematically analyse the phenotype, cytokine profile and frequency of interleukin-17 (IL-17) producing CD4-positive T cells in mononuclear cells isolated from peripheral blood, synovial fluid and synovial tissue of RA patients with established disease, and to correlate cell frequencies with disease activity. 相似文献169.
Silva FR Moraes GJ Gondim MG Knapp M Rouam SL Paes JL Oliveira GM 《Neotropical Entomology》2010,39(6):991-995
The spider mite Tetranychus evansi Baker & Pritchard can cause severe damage to tomato crops. The predatory mite Phytoseiulus longipes Evans was recently reported in association with T. evansi in Uruguaiana, Rio Grande do Sul State, Brazil. The objective of the present study was to evaluate the effects of P. longipes on the population of T. evansi on tomatoes under screenhouse condition. The study consisted on four experiments, in each of which 80 potted plantlets were distributed in two plots of 40 plantlets each. Two weeks later, each plantlet of both plots was infested with eight adult females of T. evansi; one week after, four adult females of P. longipes were released onto each plant of one plot. The population levels of T. evansi and the damage caused by these mites were significantly lower (P < 0.05; linear mixed-effect model) in the plots where P. longipes had been released. The results indicate the potential of this predator as a candidate for classical biological control of T. evansi by inoculative releases on tomato plants. 相似文献
170.
Rosângela V Andrade Hugo C Paes André M Nicola Maria José A de Carvalho Ana Lúcia Fachin Renato S Cardoso Simoneide S Silva Larissa Fernandes Silvana P Silva Eduardo A Donadi Elza T Sakamoto-Hojo Geraldo AS Passos Célia MA Soares Marcelo M Brígido Maria Sueli S Felipe 《BMC genomics》2006,7(1):1-13