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101.
Filipe Anibal Carvalho‐Costa Silvia M Dos Santos Marize Quinhones Pires Catarina Macedo Lopes François Noireau Raquel S. Pacheco 《Journal of vector ecology》2010,35(2):295-300
Chagas disease remains a public health concern in Brazil and other Latin American countries, mainly due to the potential domiciliation of native triatomine species. We analyzed the genetic variability of Triatoma pseudomaculata in sylvatic and peridomestic ecotopes throughout three localities in the northeastern state of Bahia, Brazil. We studied polymorphisms generated by random amplified polymorphic DNA (RAPD) and isoenzyme electrophoresis analyses. Based on RAPD analysis, each specimen was assigned to one of three genetic clusters. Although all sylvatic specimens from one locality were grouped into the same cluster, sylvatic and peridomestic specimens from the other two localities were broadly distributed between the remaining two clusters, suggesting that geographic population structuring was not occurring. Furthermore, isoenzyme analysis suggested that distinct populations were in Hardy‐Weinberg equilibrium. Low statistical values for Wright's Fst index also supported the absence of population structuring and suggested the occurrence of panmixia. We conclude that genetic flow occurs between sylvatic and peridomestic T. pseudomaculata populations, probably as a consequence of passive and active dispersion of the insects, associated with deforestation and anthropic transformations. 相似文献
102.
Eliane S. Meier Felix Kienast Peter B. Pearman Jens‐Christian Svenning Wilfried Thuiller Miguel B. Araújo Antoine Guisan Niklaus E. Zimmermann 《Ecography》2010,33(6):1038-1048
Abiotic factors such as climate and soil determine the species fundamental niche, which is further constrained by biotic interactions such as interspecific competition. To parameterize this realized niche, species distribution models (SDMs) most often relate species occurrence data to abiotic variables, but few SDM studies include biotic predictors to help explain species distributions. Therefore, most predictions of species distributions under future climates assume implicitly that biotic interactions remain constant or exert only minor influence on large‐scale spatial distributions, which is also largely expected for species with high competitive ability. We examined the extent to which variance explained by SDMs can be attributed to abiotic or biotic predictors and how this depends on species traits. We fit generalized linear models for 11 common tree species in Switzerland using three different sets of predictor variables: biotic, abiotic, and the combination of both sets. We used variance partitioning to estimate the proportion of the variance explained by biotic and abiotic predictors, jointly and independently. Inclusion of biotic predictors improved the SDMs substantially. The joint contribution of biotic and abiotic predictors to explained deviance was relatively small (~9%) compared to the contribution of each predictor set individually (~20% each), indicating that the additional information on the realized niche brought by adding other species as predictors was largely independent of the abiotic (topo‐climatic) predictors. The influence of biotic predictors was relatively high for species preferably growing under low disturbance and low abiotic stress, species with long seed dispersal distances, species with high shade tolerance as juveniles and adults, and species that occur frequently and are dominant across the landscape. The influence of biotic variables on SDM performance indicates that community composition and other local biotic factors or abiotic processes not included in the abiotic predictors strongly influence prediction of species distributions. Improved prediction of species' potential distributions in future climates and communities may assist strategies for sustainable forest management. 相似文献
103.
Brian J. Goodfellow Iven C. N. Duarte Anjos L. Macedo Brian F. Volkman Sofia G. Nunes I. Moura John L. Markley José J. G. Moura 《Journal of biological inorganic chemistry》2010,15(3):409-420
The Ni(II) and Zn(II) derivatives of Desulfovibrio vulgaris rubredoxin (DvRd) have been studied by NMR spectroscopy to probe the structure at the metal centre. The βCH2 proton pairs from the cysteines that bind the Ni(II) atom have been identified using 1D nuclear Overhauser enhancement (NOE)
difference spectra and sequence specifically assigned via NOE correlations to neighbouring protons and by comparison with
the published X-ray crystal structure of a Ni(II) derivative of Clostridium pasteurianum rubredoxin. The solution structures of DvRd(Zn) and DvRd(Ni) have been determined and the paramagnetic form refined using
pseudocontact shifts. The determination of the magnetic susceptibility anisotropy tensor allowed the contact and pseudocontact
contributions to the observed chemical shifts to be obtained. Analysis of the pseudocontact and contact chemical shifts of
the cysteine Hβ protons and backbone protons close to the metal centre allowed conclusions to be drawn as to the geometry
and hydrogen-bonding pattern at the metal binding site. The importance of NH–S hydrogen bonds at the metal centre for the
delocalization of electron spin density is confirmed for rubredoxins and can be extrapolated to metal centres in Cu proteins:
amicyanin, plastocyanin, stellacyanin, azurin and pseudoazurin. 相似文献
104.
Luciane A. Faine Danielle M.H. Cavalcanti Martina Rudnicki Simone Ferderbar Sandra M.D. Macedo Heraldo P. Souza Sandra H.P. Farsky Lisardo Boscá Dulcineia Saes Parra Abdalla 《The Journal of nutritional biochemistry》2010,21(2):125-132
The vascular effects of nitrolinoleate (LNO2), an endogenous product of linoleic acid (LA) nitration by nitric oxide-derived species and a potential nitrosating agent, were investigated on rat endothelial-leukocyte interactions. Confocal microscopy analysis demonstrated that LNO2 was capable to deliver free radical nitric oxide (·NO) into cells, 5 min after its administration to cultured cells, with a peak of liberation at 30 min. THP-1 monocytes incubated with LNO2 for 5 min presented nitrosation of CD40, leading to its inactivation. Other anti-inflammatory actions of LNO2 were observed in vivo by intravital microscopy assays. LNO2 decreased the number of adhered leukocytes in postcapillary venules of the mesentery network. In addition to this, LNO2 reduced mRNA and protein expression of β2-integrin in circulating leukocytes, as well as VCAM-1 in endothelial cells isolated from postcapillary venules, confirming its antiadhesive effects on both cell types. Moreover, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, a nitric oxide scavenger, partially abolished the inhibitory action of LNO2 on leukocyte-endothelium interaction, suggesting that the antiadhesion effects of LNO2 involve a dual role in leukocyte adhesion, acting as a nitric oxide donor as well as through nitric oxide-independent mechanisms. In conclusion, LNO2 inhibited adhesion molecules expression and promoted ·NO inactivation of the CD40–CD40L system, both important processes of the inflammatory response. 相似文献
105.
Zeina Daher Ghislaine Recorbet Benoît Valot Frank Robert Thierry Balliau Sophie Potin Benoît Schoefs Eliane Dumas‐Gaudot 《Proteomics》2010,10(11):2123-2137
Despite the recognized importance of non‐photosynthetic plastids in a wide array of plant processes, the root plastid proteome of soil‐grown plants still remains to be explored. In this study, we used a protocol allowing the isolation of Medicago truncatula root plastids with sufficient protein recovery and purity for their subsequent in‐depth analysis by nanoscale capillary LC‐MS/MS. Besides providing the first picture of a root plastid proteome, the results obtained highlighted the identification of 266 protein candidates whose functional distribution mainly resembled that of wheat endosperm amyloplasts and tobacco proplastids together with displaying major differences to those reported for chloroplasts. Most of the identified proteins have a role in nucleic acid‐related processes (16%), carbohydrate (15%) and nitrogen/sulphur (12%) metabolisms together with stress response mechanisms (10%). It is noteworthy that BLAST searches performed against the proteins reported in different plastidomes allowed detecting 30 putative root plastid proteins for which homologues were previously unsuspected as plastid‐located, most of them displaying a common putative role in participating in the plant cell responses against abiotic and/or biotic stresses. Taken together, the data obtained provide new insights into the functioning of root plastids and reinforce the emerging idea for an important role of these organelles in sustaining plant defence reactions. 相似文献
106.
107.
108.
A. Z. Miller M. A. Rogerio-Candelera L. Laiz J. Wierzchos C. Ascaso M. A. Sequeira Braga M. Hernández-Mariné A. Maurício A. Dionísio M. F. Macedo C. Saiz-Jimenez 《Microbial ecology》2010,60(1):55-68
This study is aimed to assess the formation of photosynthetic biofilms on and within different natural stone materials, and to analyse their biogeophysical and biogeochemical deterioration potential. This was performed by means of artificial colonisation under laboratory conditions during 3 months. Monitoring of microbial development was performed by image analysis and biofilm biomass estimation by chlorophyll extraction technique. Microscopy investigations were carried out to study relationships between microorganisms and the mineral substrata. The model applied in this work corroborated a successful survival strategy inside endolithic microhabitat, using natural phototrophic biofilm cultivation, composed by cyanobacteria and algae, which increased intrinsic porosity by active mineral dissolution. We observed the presence of mineral-like iron derivatives (e.g. maghemite) around the cells and intracellularly and the precipitation of hausmannite, suggesting manganese transformations related to the biomineralisation. 相似文献
109.
J. M. Maia C. E. Costa de Macedo E. L. Voigt J. B. S. Freitas J. A. G. Silveira 《Biologia Plantarum》2010,54(1):159-163
The aim of this work was to investigate the role of the antioxidant enzymes in salt tolerance comparing the salt-sensitive
(Pérola) and a salt-tolerant (Pitiúba) cultivar of cowpea [Vigna unguiculata (L.) Walp.]. Salt stress (100 mM NaCl for 8 d) reduced the leaf growth rate more in the sensitive cultivar. The salt-induced
decrease in the relative water content, Na+ accumulation and increase in leaf electrolyte leakage was similar in both cultivars. Salt stress induced a higher increase
in the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and phenol peroxidase (POX) in the tolerant cultivar
than in sensitive one. 相似文献
110.
Joana Tomomi Sumikawa Marlon Vilela de Brito Maria Ligia Rodrigues Macedo Adriana F. Uchoa Antonio Miranda Ana Paula U. Araujo Rosemeire A. Silva-Lucca Misako Uemura Sampaio Maria Luiza Vilela Oliva 《Phytochemistry》2010,71(2-3):214-220
Three plant proteinase inhibitors BbKI (kallikrein inhibitor) and BbCI (cruzipain inhibitor) from Bauhinia bauhinioides, and a BrTI (trypsin inhibitor) from B. rufa, were examined for other effects in Callosobruchus maculatus development; of these only BrTI affected bruchid emergence. BrTI and BbKI share 81% identities in their primary sequences and the major differences between them are the regions comprising the RGD and RGE motifs in BrTI. These sequences were shown to be essential for BrTI insecticidal activity, since a modified BbKI [that is a recombinant form (BbKIm) with some amino acid residues replaced by those found in BrTI sequence] also strongly inhibited insect development. By using synthetic peptides related to the BrTI sequence, YLEAPVARGDGGLA-NH2 (RGE) and IVYYPDRGETGL-NH2 (RGE), it was found that the peptide with an RGE sequence was able to block normal development of C. maculatus larvae (ED50 0.16% and LD50 0.09%), this being even more effective than the native protein. 相似文献