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41.
Leipold E DeBie H Zorn S Borges A Olivera BM Terlau H Heinemann SH 《Channels (Austin, Tex.)》2007,1(4):253-262
The muO-conotoxins MrVIA and MrVIB are 31-residue peptides from Conus marmoreus, belonging to the O-superfamily of conotoxins with three disulfide bridges. They have attracted attention because they are inhibitors of tetrodotoxin-insensitive voltage-gated sodium channels (Na(V)1.8) and could therefore serve as lead structure for novel analgesics. The aim of this study was to elucidate the molecular mechanism by which muO-conotoxins affect Na(V) channels. Rat Na(V)1.4 channels and mutants thereof were expressed in mammalian cells and were assayed with the whole-cell patch-clamp method. Unlike for the M-superfamily mu-conotoxin GIIIA from Conus geographus, channel block by MrVIA was strongly diminished after activating the Na(V) channels by depolarizing voltage steps. Searching for the source of this voltage dependence, the gating charges in all four-voltage sensors were reduced by site-directed mutagenesis showing that alterations of the voltage sensor in domain-2 have the strongest impact on MrVIA action. These results, together with previous findings that the effect of MrVIA depends on the structure of the pore-loop in domain-3, suggest a functional similarity with scorpion beta-toxins. In fact, MrVIA functionally competed with the scorpion beta-toxin Ts1 from Tityus serrulatus, while it did not show competition with mu-GIIIA. Ts1 and mu-GIIIA did not compete either. Thus, similar to scorpion beta-toxins, muO-conotoxins are voltage-sensor toxins targeting receptor site-4 on Na(V) channels. They "block" Na(+) flow most likely by hindering the voltage sensor in domain-2 from activating and, hence, the channel from opening. 相似文献
42.
Santos LC Ramos EA Gurgel CA de Santana EJ Dos Santos JN 《Journal of molecular histology》2007,38(3):201-205
Objective Dental granulomas (DGs) and radicular cysts (RCs) are chronic periapical lesions frequently involving the jaws. Langerhans
cells (LCs) are dendritic cells responsible for the presentation of antigens to T lymphocytes. This study examined the expression
of LCs in DG and RCs by immunohistochemical staining.
Study Design Eighteen cases of DGs and 26 cases of RCs were analyzed using anti-CD1a marker.
Results CD1a-labeled LCs were observed in 11.1% of DGs and in 69.2% of RCs, showing a significant correlation (P < 0.0001; Fisher’s test). In DGs, LCs were only observed in granulation tissue, showing discrete immunostaining density.
In RCs, LCs exhibited both a round and a dendritic shape in all epithelial layers. Although a correlation was observed between
immunostaining density and epithelial thickness, as well as between immunostaining and inflammatory intensity, the differences
were not significant in radicular cysts.
Conclusion Langerhans cells provide important insight into the immunopathogenesis of chronic periapical lesions. 相似文献
43.
Amaral Joo Henrique Fernandes Melack John Michael Barbosa Pedro Maia Borges Alberto V. Kasper Daniele Corts Alicia Cortes Zhou Wencai MacIntyre Sally Forsberg Bruce Rider 《Ecosystems》2022,25(4):911-930
Ecosystems - Extensive floodplains and numerous lakes in the Amazon basin are well suited to examine the role of floodable lands within the context of the sources and processing of carbon within... 相似文献
44.
Srgio Henrique Borges Fabricio Baccaro Marcelo Moreira Erik Lacerda Choueri 《Biotropica》2019,51(6):903-912
The principles of island biogeography are rarely applied to the animal assemblages of Amazonian river islands. Here, we compare bird assemblages of Amazonian river islands with a variety of mainland habitats. We also examine how bird species diversity and composition are related to island physical attributes. Birds were sampled with mist nets and qualitative censuses on 11 river islands and 24 mainland sites on the lower reaches of the Rio Negro in the Brazilian Amazon. Island bird assemblages were characterized by lower species richness and a higher abundance of a few dominant species. Additionally, the species composition of the islands was distinct from that of the mainland, including the nearby floodplain habitats. The number of bird species increased with island size and habitat diversity, and decreased with degree of isolation. In addition, small islands tended to harbor an impoverished subset of the species present on larger ones. Bird species diversity and composition on Amazonian river islands are likely influenced by the ecological succession and historical events affecting island formation. Considering their small total area across the Amazon basin, these insular fluvial communities could be disproportionately threatened by river channel disturbances related to climate change or hydroelectric dam development. Abstract in Portughese is available with online material. 相似文献
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de Oliveira Hellen Oliveira de Castro Gledson Luiz Salgado Correa Lorena Oliveira Silvestre Walter Vellasco Duarte do Nascimento Sidney Vasconcelos da Silva Valadares Rafael Borges de Oliveira Guilherme Corrêa Santos Rodolfo Inacio Nunes Festucci-Buselli Reginaldo Alves Pinheiro Hugo Alves 《Photosynthesis research》2019,140(2):189-205
Photosynthesis Research - This study examined whether drought sensitivity in açaí (Euterpe oleracea Mart.) is associated with reductions in photosynthesis and increasing oxidative stress... 相似文献
48.
An important factor that hinders the management of non‐native species is a general lack of information regarding the biogeography of non‐natives, and, in particular, their rates of turnover. Here, we address this research gap by analysing differences in temporal beta‐diversity (using both pairwise and multiple‐time dissimilarity metrics) between native and non‐native species, using a novel time‐series dataset of arthropods sampled in native forest fragments in the Azores. We use a null model approach to determine whether temporal beta‐diversity was due to deterministic processes or stochastic colonisation and extinction events, and linear modelling selection to assess the factors driving variation in temporal beta‐diversity between plots. In accordance with our predictions, we found that the temporal beta‐diversity was much greater for non‐native species than for native species, and the null model analyses indicated that the turnover of non‐native species was due to stochastic events. No predictor variables were found to explain the turnover of native or non‐native species. We attribute the greater turnover of non‐native species to source‐sink processes and the close proximity of anthropogenic habitats to the fragmented native forest plots sampled in our study. Thus, our findings point to ways in which the study of turnover can be adapted for future applications in habitat island systems. The implications of this for biodiversity conservation and management are significant. The high rate of stochastic turnover of non‐native species indicates that attempts to simply reduce the populations of non‐native species in situ within native habitats may not be successful. A more efficient management strategy would be to interrupt source‐sink dynamics by improving the harsh boundaries between native and adjacent anthropogenic habitats. 相似文献
49.
Maria Isabel Mendona Eva Henriques Sofia Borges Ana Clia Sousa Andreia Pereira Marina Santos Margarida Temtem Snia Freitas Joel Monteiro Joo Adriano Sousa Ricardo Rodrigues Graa Guerra Roberto Palma dos Reis 《Genetics and molecular biology》2021,44(2)
The inclusion of a genetic risk score (GRS) can modify the risk prediction of coronary artery disease (CAD), providing an advantage over the use of traditional models. The predictive value of the genetic information on the recurrence of major adverse cardiovascular events (MACE) remains controversial. A total of 33 genetic variants previously associated with CAD were genotyped in 1587 CAD patients from the GENEMACOR study. Of these, 18 variants presented an hazard ratio >1, so they were selected to construct a weighted GRS (wGRS). MACE discrimination and reclassification were evaluated by C-Statistic, Net Reclassification Index and Integrated Discrimination Improvement methodologies. After the addition of wGRS to traditional predictors, the C-index increased from 0.566 to 0.572 (p=0.0003). Subsequently, adding wGRS to traditional plus clinical risk factors, this model slightly improved from 0.620 to 0.622 but with statistical significance (p=0.004). NRI showed that 17.9% of the cohort was better reclassified when the primary model was associated with wGRS. The Kaplan-Meier estimator showed that, at 15-year follow-up, the group with a higher number of risk alleles had a significantly higher MACE occurrence (p=0.011). In CAD patients, wGRS improved MACE risk prediction, discrimination and reclassification over the conventional factors, providing better cost-effective therapeutic strategies. 相似文献
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