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992.
Mariana Fasanella Cecilia Bruno Yamila Cardoso Marta Lizarralde 《Zoological Journal of the Linnean Society》2013,169(3):697-710
Ctenomys (tuco‐tuco) is the most numerous genus of South American subterranean rodents and one of the most genetically diverse clades of mammals known. In particular, the genus constitutes a very interesting model for evolutionary studies of genetic divergence and conservation. Ctenomys magellanicus is the southernmost species of the group and the only one living in Isla Grande de Tierra del Fuego (Argentina). This species presents two chromosomal forms (Cm34 and Cm36) fragmented into demes distributed from the north region (steppe) to the south region (ecotone) of the island, respectively; no hybrids or overlapping areas were detected. To study the historical demography and the spatial genetic structure of the C. magellanicus population we used mitochondrial DNA (mtDNA) (D‐loop and cytochrome b) and microsatellite loci. Nine mtDNA haplotypes were identified, three of them belonging to the north and the other six to the south. Shared haplotypes between regions were not detected. mtDNA and microsatellite genotypes showed a marked pattern of population structure with low values of genetic flow between regions. The south is made up of small populations or isolated demes making up an endogamic metapopulation with unique alleles and haplotypes. Also, the results suggest a northward expansion process starting from an ancestral haplotype from the south. That population might have lived at a refuge through the adverse Pleistocene environmental conditions that took place at Tierra del Fuego. Results of this study are relevant to the conservation of C. magellanicus, suggesting that each region (north and south) might be considered as an Evolutionarily Significant Unit. © 2013 The Linnean Society of London 相似文献
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994.
Mariana Craciun 《Ethnic and racial studies》2013,36(5):729-746
Immigration historians have illuminated the institutional forces that made possible Eastern and southern European immigrants' inclusion in the white racial category in the early twentieth century, initiating their ascent into mainstream America. Sociologists have shown that their descendants assimilated into American society while maintaining symbolic attachments to their ethnic roots. But, whereas current studies of immigrant racialization have focused on the strategies of immigrants of colour for asserting a higher position in the American social hierarchy, scholars have generally overlooked such processes for phenotypically white immigrants. This paper highlights first and 1.5 generation Romanian immigrants' strategies for navigating their ambivalent relationship to Americanness. While they assumed their whiteness unproblematically, Romanian Americans sought to distinguish themselves from whites and non-whites on the basis of their ethnicity. Furthermore, they used American values to distance themselves from their former compatriots. Through moral bricolage, Romanians made strategic use of desirable traits they associated with being Romanian and American, melding them into a particularly worthy ethnic identity. 相似文献
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996.
Marcio Roberto Silva Adalgiza da Silva Rocha Ronaldo Rodrigues da Costa Andrea Padilha de Alencar Vania Maria de Oliveira Ant?nio Augusto Fonseca Júnior Mariana Lázaro Sales Marina de Azevedo Issa Paulo Martins Soares Filho Omara Tereza Vianello Pereira Eduardo Calazans dos Santos Rejane Silva Mendes ?ngela Maria de Jesus Ferreira Pedro Moacyr Pinto Coelho Mota Philip Noel Suffys Mark Drew Crosland Guimar?es 《Memórias do Instituto Oswaldo Cruz》2013,108(3):321-327
In this cross-sectional study, mycobacteria specimens from 189 tuberculosis (TB) patients living in an urban area in Brazil were characterised from 2008-2010 using phenotypic and molecular speciation methods (pncA gene and oxyR pseudogene analysis). Of these samples, 174 isolates simultaneously grew on Löwenstein-Jensen (LJ) and Stonebrink (SB)-containing media and presented phenotypic and molecular profiles of Mycobacterium tuberculosis, whereas 12 had molecular profiles of M. tuberculosis based on the DNA analysis of formalin-fixed paraffin wax-embedded tissue samples (paraffin blocks). One patient produced two sputum isolates, the first of which simultaneously grew on LJ and SB media and presented phenotypic and molecular profiles of M. tuberculosis, and the second of which only grew on SB media and presented phenotypic profiles of Mycobacterium bovis. One patient provided a bronchial lavage isolate, which simultaneously grew on LJ and SB media and presented phenotypic and molecular profiles of M. tuberculosis, but had molecular profiles of M. bovis from paraffin block DNA analysis, and one sample had molecular profiles of M. tuberculosis and M. bovis identified from two distinct paraffin blocks. Moreover, we found a low prevalence (1.6%) of M. bovis among these isolates, which suggests that local health service procedures likely underestimate its real frequency and that it deserves more attention from public health officials. 相似文献
997.
Constanza Giselle Taverna María Eugenia Bosco-Borgeat Omar Alejandro Murisengo Graciela Davel Mariana C?rtes Boité Elisa Cupolillo Cristina Elena Canteros 《Memórias do Instituto Oswaldo Cruz》2013,108(2):178-185
As the distribution of Candida species and their susceptibility to antifungal agents have changed, a new means of accurately and rapidly identifying these species is necessary for the successful early resolution of infection and the subsequent reduction of morbidity and mortality. The current work aimed to evaluate ribosomal RNA gene sequencing for the identification of medically relevant Candida species in comparison with a standard phenotypic method. Eighteen reference strains (RSs), 69 phenotypically identified isolates and 20 inconclusively identified isolates were examined. Internal transcribed spaces (ITSs) and D1/D2 of the 26S ribosomal RNA gene regions were used as targets for sequencing. Additionally, the sequences of the ITS regions were used to establish evolutionary relationships. The sequencing of the ITS regions was successful for 88% (94/107) of the RS and isolates, whereas 100% of the remaining 12% (13/107) of the samples were successfully analysed by sequencing the D1/D2 region. Similarly, genotypic analysis identified all of the RS and isolates, including the 20 isolates that were not phenotypically identified. Phenotypic analysis, however, misidentified 10% (7/69) of the isolates. Phylogenetic analysis allowed the confirmation of the relationships between evolutionarily close species. Currently, the use of genotypic methods is necessary for the correct identification of Candida species. 相似文献
998.
Filomena S. G. Silva Mariana P. C. Ribeiro Maria S. Santos Petronila Rocha-Pereira Alice Santos-Silva José B. A. Custódio 《Journal of bioenergetics and biomembranes》2013,45(4):383-396
The combination of isotretinoin (13-cis-retinoic acid) with antiestrogens seems to be a promising strategy for cancer chemotherapy. The aim of the study was to evaluate the effects of isotretinoin alone or in combination with 4-hydroxytamoxifen (OHTAM) and with its prodrug tamoxifen (TAM), on the functions of rat liver mitochondria, i.e., mitochondrial permeability transition (MPT), bioenergetic functions and adenine nucleotide translocase (ANT). Isotretinoin (5 nmol/mg protein) induced the Ca2+-dependent MPT pore opening in mitochondria energized with succinate, which was prevented by OHTAM, cyclosporine A, TAM and ANT ligands. When mitochondria were energized with glutamate/malate and in the absence of added Ca2+ isotretinoin decreased the state 3 respiration, the ATP levels, the active ANT content and increased the lag phase of the phosphorylation cycle, demonstrating that isotretinoin decreased the mitochondrial phosphorylation efficiency. These changes of isotretinoin in bioenergetic parameters were not significant in the presence of succinate. The effects of isotretinoin at 5 nmol/mg protein on the Ca2+-dependent MPT and phosphorylative efficacy may be related with interactions with the ANT. Above 10 nmol/mg protein isotretinoin strongly diminished the active ANT content, decreased the Δψ, inhibited the complex I and induced proton leak through the Fo fraction of complex V. The combination of OHTAM with isotretinoin only induced significant changes in the energy production systems at concentrations ≥5 nmol isotretinoin/mg protein. Therefore, our results suggest that isotretinoin-associated liver toxicity is possibly related with mitochondrial dysfunctions and that the combination with OHTAM may contribute to decrease its toxicity. 相似文献
999.
Mariana Lozada Nadia Guthmann Nora Baccala 《Studies on Neotropical Fauna and Environment》2013,48(2):85-90
In a transition zone between Andean forests and Patagonian steppe, local populations of five sympatric species of sigmodontine rodents (Abrothrix longipilis, A. xanthorhinus, Eligmodontia morgani, Oligoryzomys longicaudatus, Reithrodon auritus) were examined for their microhabitat use. The study area represents a herbaceous steppe with sparse bushes. Over a four-year period, monthly samples were obtained by baited traps. The vegetation cover at each trapsite was monitored. The capture frequency in a particular microhabitat turned out to be strongly correlated with the local vegetation cover. This result is interpreted as a species-specific selection at a fine spatial scale of those microsites which resemble the characteristic environment in the area of main biogeographic occurrence of each of the rodents. The data on preferential microhabitat use might gather importance considering that two of these sigmodontine species are Hantavirus reservoirs. 相似文献
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