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61.
The nitrogen fixer Azospirillum amazonense grew on the various disaccharides, hexoses, and pentoses tested in this study but not on polyols and on some tricarboxylic acid cycle intermediates. An active transport system was detected for sucrose and glucose but not for mannitol and 2-ketoglutarate. Six A. amazonense strains were examined for 16 carbon-metabolizing enzymes, and the results indicate that these strains employ the Entner-Doudoroff pathway to catabolize sucrose, fructose, and glucose. The hexose monophosphate and Embden-Meyerhof-Parnas pathways were not detectable. 相似文献
62.
Effects of skeletal element identity,delipidation and demineralization on the analysis of stable isotope ratios of C and N in fish bone
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Stable isotope ratios of C and N in the bone tissue of three different skeletal elements (angular, cleithrum and vertebra) of three fish species from different evolutionary lineages (Clupeiformes, Atheriniformes and Notothenioidei) were determined before (δ13Cbulk and δ15Nbulk) and after demineralization and delipidation (δ13Cdml and δ15Ndml). One of the species had cellular bone and the other two had acellular bone. Results revealed that δ15N and δ13C values from different skeletal elements were interchangeable in species with acellular bone, but caution was needed in species with cellular bone, as δ15N values varied among skeletal elements. Furthermore, δ15Nbulk values were significantly lower than δ15Ndml values in the three species, thus suggesting that they are not comparable. This difference is probably because δ15Nbulk refers to total bone protein and δ15Ndml to collagen only. 相似文献
63.
The integration of alien plants in mutualistic plant–hummingbird networks across the Americas: the importance of species traits and insularity
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Pietro K. Maruyama Jeferson Vizentin‐Bugoni Jesper Sonne Ana M. Martín González Matthias Schleuning Andréa C. Araujo Andrea C. Baquero Juliana Cardona Paola Cardona Peter A. Cotton Glauco Kohler Carlos Lara Tiago Malucelli Oscar Humberto Marín‐Gómez Jeff Ollerton Ana M. Rui Allan Timmermann Isabela G. Varassin Thais B. Zanata Carsten Rahbek Marlies Sazima Bo Dalsgaard 《Diversity & distributions》2016,22(6):672-681
64.
65.
Nobrega C Cardona PJ Roque S Pinto do O P Appelberg R Correia-Neves M 《Microbes and infection / Institut Pasteur》2007,9(14-15):1521-1529
Mycobacterial infections are among the major health threats worldwide. Ability to fight these infections depends on the host's immune response, particularly on macrophages and T lymphocytes produced by the thymus. Using the mouse as a model, and two different routes of infection (aerogenic or intravenous), we show that the thymus is consistently colonized by Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium bovis BCG. When compared to organs such as the liver and spleen, the bacterial load reaches a plateau at later time-points after infection. Moreover, in contrast with organs such as the spleen and the lung no granuloma were found in the thymus of mice infected with M. tuberculosis or M. avium. Since T cell differentiation depends, to a large extent, on the antigens encountered within the thymus, infection of this organ might alter the host's immune response to infection. Therefore, from now on, the thymus should be considered in studies addressing the immune response to mycobacterial infection. 相似文献
66.
67.
Pierre Vandurm Christine Cauvin Allan Guiguen Benoît Georges Kiet Le Van Valérie Martinelli Christelle Cardona Gladys Mbemba Jean-François Mouscadet László Hevesi Carine Van Lint Johan Wouters 《Bioorganic & medicinal chemistry letters》2009,19(16):4806-4809
Ethyl [6-bromo-1-(4-fluorophenylmethyl)-4(1H)-quinolinon-3-yl]-4-hydroxy-2-oxo-3-butenoate 1 and [6-bromo-1-(4-fluorophenylmethyl)-4(1H)-quinolinon-3-yl)]-4-hydroxy-2-oxo-3-butenoïc acid 2 were synthesized as potential HIV-1 integrase inhibitors and evaluated for their enzymatic and antiviral activity, acidic compound 2 being more potent than ester compound 1. X-ray diffraction analyses and theoretical calculations show that the diketoacid chain of compound 2 is preferentially coplanar with the quinolinone ring (dihedral angle of 0–30°). Docking studies suggest binding modes in agreement with structure–activity relationships. 相似文献
68.
Filamentous, heterocystous cyanobacteria are capable of nitrogen fixation and photoautotrophic growth. Nitrogen fixation takes place in heterocysts that differentiate as a result of nitrogen starvation. Heterocysts uphold a microoxic environment to avoid inactivation of nitrogenase, e.g. by downregulation of oxygenic photosynthesis. The ATP and reductant requirement for the nitrogenase reaction is considered to depend on Photosystem I, but little is known about the organization of energy converting membrane proteins in heterocysts. We have investigated the membrane proteome of heterocysts from nitrogen fixing filaments of Nostoc punctiforme sp. PCC 73102, by 2D gel electrophoresis and mass spectrometry. The membrane proteome was found to be dominated by the Photosystem I and ATP-synthase complexes. We could identify a significant amount of assembled Photosystem II complexes containing the D1, D2, CP43, CP47 and PsbO proteins from these complexes. We could also measure light-driven in vitro electron transfer from Photosystem II in heterocyst thylakoid membranes. We did not find any partially disassembled Photosystem II complexes lacking the CP43 protein. Several subunits of the NDH-1 complex were also identified. The relative amount of NDH-1M complexes was found to be higher than NDH-1L complexes, which might suggest a role for this complex in cyclic electron transfer in the heterocysts of Nostoc punctiforme. 相似文献
69.
Francisco Tinahones Julian Salas María Dolores Mayas Adrian Ruiz-Villalba Manuel Macias-Gonzalez Lourdes Garrido-Sanchez Manuel DeMora Inmaculada Moreno-Santos Rosa Bernal Fernando Cardona Rajaa El Bekay 《PloS one》2009,4(12)
It is well known that the adult human thymus degenerates into fat tissue; however, it has never been considered as a potential source of angiogenic factors. Recently, we have described that this fat (TAT) produces angiogenic factors and induces human endothelial cell proliferation and migration, indicating its potential angiogenic properties.
Design
Adult thymus fat and subcutaneous adipose tissue specimens were obtained from 28 patients undergoing cardiac surgery, making this tissue readily available as a prime source of adipose tissue. We focused our investigation on determining VEGF gene expression and characterizing the different genes, mediators of inflammation and adipogenesis, and which are known to play a relevant role in angiogenesis regulation.Results
We found that VEGF-A was the isoform most expressed in TAT. This expression was accompanied by an upregulation of HIF-1α, COX-2 and HO-1 proteins, and by increased HIF-1 DNA binding activity, compared to SAT. Furthermore, we observed that TAT contains a high percentage of mature adipocytes, 0.25% of macrophage cells, 15% of endothelial cells and a very low percentage of thymocyte cells, suggesting the cellular variability of TAT, which could explain the differences in gene expression observed in TAT. Subsequently, we showed that the expression of genes known as adipogenic mediators, including PPARγ1/γ2, FABP-4 and adiponectin was similar in both TAT and SAT. Moreover the expression of these latter genes presented a significantly positive correlation with VEGF, suggesting the potential association between VEGF and the generation of adipose tissue in adult thymus.Conclusion
Here we suggest that this fat has a potential angiogenic function related to ongoing adipogenesis, which substitutes immune functions within the adult thymus. The expression of VEGF seems to be associated with COX-2, HO-1 and adipogenesis related genes, suggesting the importance that this new fat has acquired in research in relation to adipogenesis and angiogenesis. 相似文献70.
Gabriel Cardona Mercè Llabrés Francesc Rosselló Gabriel Valiente 《Journal of mathematical biology》2010,61(2):253-276
Dissimilarity measures for (possibly weighted) phylogenetic trees based on the comparison of their vectors of path lengths
between pairs of taxa, have been present in the systematics literature since the early seventies. For rooted phylogenetic
trees, however, these vectors can only separate non-weighted binary trees, and therefore these dissimilarity measures are
metrics only on this class of rooted phylogenetic trees. In this paper we overcome this problem, by splitting in a suitable
way each path length between two taxa into two lengths. We prove that the resulting splitted path lengths matrices single out arbitrary rooted phylogenetic trees with nested taxa and arcs weighted in the set of positive real numbers. This
allows the definition of metrics on this general class of rooted phylogenetic trees by comparing these matrices through metrics
in spaces
Mn(\mathbb R){\mathcal{M}_n(\mathbb {R})} of real-valued n × n matrices. We conclude this paper by establishing some basic facts about the metrics for non-weighted phylogenetic trees defined
in this way using L
p
metrics on
Mn(\mathbb R){\mathcal{M}_n(\mathbb {R})}, with ${p \in \mathbb {R}_{ >0 }}${p \in \mathbb {R}_{ >0 }}. 相似文献