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991.
Marcelo L Laia Leandro M Moreira Juliana Dezajacomo Joice B Brigati Cristiano B Ferreira Maria IT Ferro Ana CR Silva Jesus A Ferro Julio CF Oliveira 《BMC microbiology》2009,9(1):12-17
Background
Citrus canker is a disease caused by the phytopathogens Xanthomonas citri subsp. citri, Xanthomonas fuscans subsp. aurantifolli and Xanthomonas alfalfae subsp. citrumelonis. The first of the three species, which causes citrus bacterial canker type A, is the most widely spread and severe, attacking all citrus species. In Brazil, this species is the most important, being found in practically all areas where citrus canker has been detected. Like most phytobacterioses, there is no efficient way to control citrus canker. Considering the importance of the disease worldwide, investigation is needed to accurately detect which genes are related to the pathogen-host adaptation process and which are associated with pathogenesis. 相似文献992.
Ghosh S Paez-Cortez JR Boppidi K Vasconcelos M Roy M Cardoso W Ai X Fine A 《The Journal of biological chemistry》2011,286(25):22678-22687
Notch3 signaling is fundamental for arterial specification of systemic vascular smooth muscle cells (VSMCs). However, the developmental role and signaling properties of the Notch3 receptor in the mouse pulmonary artery remain unknown. Here, we demonstrate that Notch3 is expressed selectively in pulmonary artery VSMCs, is activated from late fetal to early postnatal life, and is required to maintain the morphological characteristics and smooth muscle gene expression profile of the pulmonary artery after birth. Using a conditional knock-out mouse model, we show that Notch3 receptor activation in VSMCs is Jagged1-dependent. In vitro VSMC lentivirus-mediated Jagged1 knockdown, confocal localization analysis, and co-culture experiments revealed that Notch3 activation is cell-autonomous and occurs through the physical engagement of Notch3 and VSMC-derived Jagged1 in the interior of the same cell. Although the current models of mammalian Notch signaling involve a two-cell system composed of a signal-receiving cell that expresses a Notch receptor on its surface and a neighboring signal-sending cell that provides membrane-bound activating ligand, our data suggest that pulmonary artery VSMC Notch3 activation is cell-autonomous. This unique mechanism of Notch activation may play an important role in the maturation of the pulmonary artery during the transition to air breathing. 相似文献
993.
Leonardo da Silva Augusto Nilmar Silvio Moretti Thiago Cesar Prata Ramos Teresa Cristina Leandro de Jesus Min Zhang Beatriz A. Castilho Sergio Schenkman 《PLoS pathogens》2015,11(2)
Translation initiation has been described as a key step for the control of growth and differentiation of several protozoan parasites in response to environmental changes. This occurs by the activation of protein kinases that phosphorylate the alpha subunit of the translation initiation factor 2 (eIF2α), which decreases translation, and in higher eukaryotes favors the expression of stress remedial response genes. However, very little is known about the signals that activate eIF2α kinases in protozoan parasites. Here, we characterized an eIF2α kinase of Trypanosoma cruzi (TcK2), the agent of Chagas’ disease, as a transmembrane protein located in organelles that accumulate nutrients in proliferating parasite forms. We found that heme binds specifically to the catalytic domain of the kinase, inhibiting its activity. In the absence of heme, TcK2 is activated, arresting cell growth and inducing differentiation of proliferative into infective and non-proliferative forms. Parasites lacking TcK2 lose this differentiation capacity and heme is not stored in reserve organelles, remaining in the cytosol. TcK2 null cells display growth deficiencies, accumulating hydrogen peroxide that drives the generation of reactive oxygen species. The augmented level of hydrogen peroxide occurs as a consequence of increased superoxide dismutase activity and decreased peroxide activity. These phenotypes could be reverted by the re-expression of the wild type but not of a TcK2 dead mutant. These findings indicate that heme is a key factor for the growth control and differentiation through regulation of an unusual type of eIF2α kinase in T. cruzi. 相似文献
994.
Oxygen: a fundamental property regulating pelagic ecosystem structure in the coastal southeastern tropical Pacific 总被引:3,自引:0,他引:3
Bertrand A Chaigneau A Peraltilla S Ledesma J Graco M Monetti F Chavez FP 《PloS one》2011,6(12):e29558
Background
In the southeastern tropical Pacific anchovy (Engraulis ringens) and sardine (Sardinops sagax) abundance have recently fluctuated on multidecadal scales and food and temperature have been proposed as the key parameters explaining these changes. However, ecological and paleoecological studies, and the fact that anchovies and sardines are favored differently in other regions, raise questions about the role of temperature. Here we investigate the role of oxygen in structuring fish populations in the Peruvian upwelling ecosystem that has evolved over anoxic conditions and is one of the world''s most productive ecosystems in terms of forage fish. This study is particularly relevant given that the distribution of oxygen in the ocean is changing with uncertain consequences.Methodology/Principal Findings
A comprehensive data set is used to show how oxygen concentration and oxycline depth affect the abundance and distribution of pelagic fish. We show that the effects of oxygen on anchovy and sardine are opposite. Anchovy flourishes under relatively low oxygen conditions while sardine avoid periods/areas with low oxygen concentration and restricted habitat. Oxygen consumption, trophic structure and habitat compression play a fundamental role in fish dynamics in this important ecosystem.Conclusions/Significance
For the ocean off Peru we suggest that a key process, the need to breathe, has been neglected previously. Inclusion of this missing piece allows the development of a comprehensive conceptual model of pelagic fish populations and change in an ocean ecosystem impacted by low oxygen. Should current trends in oxygen in the ocean continue similar effects may be evident in other coastal upwelling ecosystems. 相似文献995.
An analytic method based on simulation and modeling of long-term 45Ca(2+) efflux data was used to estimate steady-state Ca(2+) contents (nmolCa(2+)g(-1)tissuewetwt.) and exchange fluxes (nmolCa(2+)min(-1)g(-1)tissuewetwt.) for extracellular and intracellular compartments in in vitro resting diaphragm from congestive heart failure (CHF, n=12) and sham-operated (SHAM, n=10) rats. Left hemidiaphragms were excised from experimental animals, loaded with 45Ca(2+) for 1h, and washed out with 45Ca(2+)-free perfusate for 8h. Tissue from the right hemidiaphragm was used to assess single-fiber cross-sectional area (CSA) as well as the relative proteolytic activity of Ca(2+)-dependent calpain. Kinetic analysis of 45Ca(2+) efflux data revealed that CHF was associated with increased Ca(2+) contents of extracellular and intracellular compartments as well as increased Ca(2+) exchange fluxes for all compartments. This accounted for the model prediction of a 250% increase in total diaphragm Ca(2+). Furthermore, single-fiber CSA was decreased 12% and proteolytic activity of calpain was increased twofold in CHF diaphragm relative to SHAM.CONCLUSIONS: The kinetic data are consistent with the hypothesis that diaphragm Ca(2+) overload in CHF required all intercompartmental Ca(2+) fluxes to increase. The potential relationships among Ca(2+) overload, increased activity of calpain, and wasting of the diaphragm in CHF are discussed. 相似文献
996.
Jesus Fortún Francesca Gioia Patricia Muñoz Javier Graus Elia Gómez-García de la Pedrosa Pilar Martín-Dávila Ana Saiz Antonio Vena Santiago Moreno 《Revista iberoamericana de micología》2018,35(3):159-161
Background
T2 magnetic resonance imaging (T2MR) is a new method for the diagnosis of invasive candidiasis, although most studies have analyzed its role in patients with candidemia or not infection.Case report
We present the case of a patient with arteritis and thrombosis of the hepatic graft resulted from an undocumented fungal infection in the explanted liver.T2MR in serum was a suitable diagnostic tool for the diagnosis of the deep-seated invasive candidiasis in the absence of candidemia or the isolation of the yeast in culture.Conclusions
T2MR allowed the diagnosis of deep-seated invasive candidiasis in an immunodepressed patient without candidemia, even before the onset of symptoms. 相似文献997.
The levels of haplotype diversity associated with different alpha1-antitrypsin (PI) alleles were assessed by the analysis of three microsatellites located within or close to corticosteroid-binding globulin (CBG), alpha1-antitrypsin [PI-(TG)n] and protein C inhibitor [PCI-(TG)n] loci in three populations with different historic backgrounds: Portugal, the Basque Country and S?o Tomé Príncipe (Gulf of Guinea). Unlike the more distant PCI-(TG)n repeat, allelic variation at PI-(TG)n reflected distinct phases of mutational recovery of microsatellite diversity around different founder alleles and showed a considerable differentiation between alpha1-antitrypsin protein variants. In accordance with population history, the Basque sample presented overall reduced levels of microsatellite variation. The African sample, although presenting the highest PCI-(TG)n diversity, showed a lineage-specific reduction in PI-(TG)n heterozygosity within the oldest M1Ala213 variant that could have been caused by (1) selection at a closely linked locus or (2) biases in the microsatellite mutation process leading to a stable equilibrium distribution. Age estimates of alpha1-antitrypsin variants based on microsatellite variation suggest that the Z deficiency allele appeared 107-135 generations ago and could have been spread in Neolithic times. The S mutation has an older 279- to 470-generation age, indicating that its high frequencies in Iberia did not result from a recent bottleneck and that PI*S could have originated in this region. M2 and M3 types had lower age estimates than would be expected from their wide geographical distributions, suggesting that their dispersion in Europe might have been preceded by important bottlenecks. 相似文献
998.
Background
d-α-tocopherol is a naturally occurring form of vitamin E not previously known to have antitumor activity. Synthetic vitamin E (sE) is a commonly used dietary supplement consisting of a mixture of d-α-tocopherol and 7 equimolar stereoisomers. To test for antilipid peroxidation and for antitumor activity of sE supplementation, two groups of nude mice bearing a MDA-MB 231 human breast cancer tumor were fed an AIN-76 diet, one with and one without an additional 2000 IU/kg dry food (equivalent to 900 mg of all-rac-α-tocopherol or sE). This provided an intake of about 200 mg/kg body weight per day. The mice were killed at either 2 or 6 weeks after the start of dietary intervention. During necropsy, tumor and host tissues were excised for histology and for biochemical analyses. 相似文献999.
Lianguo Wang Nicole M. De Jesus Crystal M. Ripplinger 《Journal of visualized experiments : JoVE》2015,(103)
Sarcoplasmic reticulum (SR) Ca2+ handling plays a key role in normal excitation-contraction coupling and aberrant SR Ca2+ handling is known to play a significant role in certain types of arrhythmia. Because arrhythmias are spatially distinct, emergent phenomena, they must be investigated at the tissue level. However, methods for directly probing SR Ca2+ in the intact heart remain limited. This article describes the protocol for dual optical mapping of transmembrane potential (Vm) and free intra-SR [Ca2+] ([Ca2+]SR) in the Langendorff-perfused rabbit heart. This approach takes advantage of the low-affinity Ca2+ indicator Fluo-5N, which has minimal fluorescence in the cytosol where intracellular [Ca2+] ([Ca2+]i) is relatively low but exhibits significant fluorescence in the SR lumen where [Ca2+]SR is in the millimolar range. In addition to revealing SR Ca2+ characteristics spatially across the epicardial surface of the heart, this approach has the distinct advantage of simultaneous monitoring of Vm, allowing for investigations into the bidirectional relationship between Vm and SR Ca2+ and the role of SR Ca2+ in arrhythmogenic phenomena. 相似文献
1000.
Chi-Shuo Chen Jonathan Pegan Jesus Luna Bing Xia Kara McCloskey Wei-chun Chin Michelle Khine 《Journal of visualized experiments : JoVE》2008,(13)
Embryoid bodies (EB) are aggregates of embryonic stem cells. The most common way of creating these aggregates is the hanging drop method, a laborious approach of pipetting an arbitrary number of cells into well plates. The interactions between the stem cells forced into close proximity of one another promotes the generation of the EBs. Because the media in each of the wells has to be manually exchanged every day, this approach is manually intensive.Moreover, because environmental parameters including cell-cell, cell-soluble factor interactions, pH, and oxygen availability can be functions of EB size, cell populations obtained from traditional hanging drops can vary dramatically even when cultured under identical conditions. Recent studies have indeed shown that the initial number of cells forming the aggregate can have significant effects on stem cell differentiation. We have developed a simple, rapid, and scalable culture method to load pre-defined numbers of cells into microfabricated wells and maintain them for embryoid body development. Finally, these cells are easily accessible for further analysis and experimentation. This method is amenable to any lab and requires no dedicated equipment. We demonstrate this method by creating embryoid bodies using a red fluorescent mouse cell line (129S6B6-F1).Download video file.(42M, mov) 相似文献