264 research outputs found
Functional characterization of 8-oxoguanine DNA glycosylase of Trypanosoma cruzi
The oxidative lesion 8-oxoguanine (8-oxoG) is removed during base excision repair by the 8-oxoguanine DNA glycosylase 1 (Ogg1). This lesion can erroneously pair with adenine, and the excision of this damaged base by Ogg1 enables the insertion of a guanine and prevents DNA mutation. In this report, we identified and characterized Ogg1 from the protozoan parasite Trypanosoma cruzi (TcOgg1), the causative agent of Chagas disease. Like most living organisms, T. cruzi is susceptible to oxidative stress, hence DNA repair is essential for its survival and improvement of infection. We verified that the TcOGG1 gene encodes an 8-oxoG DNA glycosylase by complementing an Ogg1-defective Saccharomyces cerevisiae strain. Heterologous expression of TcOGG1 reestablished the mutation frequency of the yeast mutant ogg1-/- (CD138) to wild type levels. We also demonstrate that the overexpression of TcOGG1 increases T. cruzi sensitivity to hydrogen peroxide (H2O2). Analysis of DNA lesions using quantitative PCR suggests that the increased susceptibility to H2O2 of TcOGG1-overexpressor could be a consequence of uncoupled BER in abasic sites and/or strand breaks generated after TcOgg1 removes 8-oxoG, which are not rapidly repaired by the subsequent BER enzymes. This hypothesis is supported by the observation that TcOGG1-overexpressors have reduced levels of 8-oxoG both in the nucleus and in the parasite mitochondrion. The localization of TcOgg1 was examined in parasite transfected with a TcOgg1-GFP fusion, which confirmed that this enzyme is in both organelles. Taken together, our data indicate that T. cruzi has a functional Ogg1 ortholog that participates in nuclear and mitochondrial BER. © 2012 Furtado et al
Development and characterization of highly polymorphic long TC repeat microsatellite markers for genetic analysis of peanut
<p>Abstract</p> <p>Background</p> <p>Peanut (<it>Arachis hypogaea </it>L.) is a crop of economic and social importance, mainly in tropical areas, and developing countries. Its molecular breeding has been hindered by a shortage of polymorphic genetic markers due to a very narrow genetic base. Microsatellites (SSRs) are markers of choice in peanut because they are co-dominant, highly transferrable between species and easily applicable in the allotetraploid genome. In spite of substantial effort over the last few years by a number of research groups, the number of SSRs that are polymorphic for <it>A. hypogaea </it>is still limiting for routine application, creating the demand for the discovery of more markers polymorphic within cultivated germplasm.</p> <p>Findings</p> <p>A plasmid genomic library enriched for TC/AG repeats was constructed and 1401 clones sequenced. From the sequences obtained 146 primer pairs flanking mostly TC microsatellites were developed. The average number of repeat motifs amplified was 23. These 146 markers were characterized on 22 genotypes of cultivated peanut. In total 78 of the markers were polymorphic within cultivated germplasm. Most of those 78 markers were highly informative with an average of 5.4 alleles per locus being amplified. Average gene diversity index (GD) was 0.6, and 66 markers showed a GD of more than 0.5. Genetic relationship analysis was performed and corroborated the current taxonomical classification of <it>A. hypogaea </it>subspecies and varieties.</p> <p>Conclusions</p> <p>The microsatellite markers described here are a useful resource for genetics and genomics in <it>Arachis</it>. In particular, the 66 markers that are highly polymorphic in cultivated peanut are a significant step towards routine genetic mapping and marker-assisted selection for the crop.</p
Characterisation of the relationships between rhythmic masticatory muscle activities and limb movements in patients with sleep bruxism
Medications and addictive substances potentially inducing or attenuating sleep bruxism and/or awake bruxism
Bruxism is a repetitive jaw-muscle activity characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible. It can occur during sleep, indicated as sleep bruxism, or during wakefulness, indicated as awake bruxism. Exogenous risk indicators of sleep bruxism and/or awake bruxism are, among others, medications and addictive substances, whereas also several medications seem to have the potential to attenuate sleep bruxism and/or awake bruxism. The objective of this study was to present a narrative literature on medications and addictive substances potentially inducing or aggravating sleep bruxism and/or awake bruxism and on medications potentially attenuating sleep bruxism and/or awake bruxism. Literature reviews reporting evidence or indications for sleep bruxism and/or awake bruxism as an adverse effect of several (classes of) medications as well as some addictive substances and literature reviews on medications potentially attenuating sleep bruxism and/or awake bruxism were used as starting point and guidelines to describe the topics mentioned. Additionally, two literature searches were established on PubMed. Three types of bruxism were distinguished: sleep bruxism, awake bruxism and non-specified bruxism. Generally, there are insufficient evidence-based data to draw definite conclusions concerning medications and addictive substances inducing or aggravating sleep bruxism and/or awake bruxism as well as concerning medications attenuating sleep bruxism and/or awake bruxism. There are insufficient evidence-based data to draw definite conclusions concerning medications and addictive substances inducing or aggravating sleep bruxism and/or awake bruxism as well as concerning medications attenuating sleep bruxism and/or awake bruxism.Peer reviewe
Experimental models of 'Basement'-controlled salients - application to the proterozoic fold-thrust belt of the quadrilátero ferrífero (Minas Gerais, Southeastern Brazil)
Postural assessment of patients with non-conventional knee endoprosthesis
Objective:To investigate the correlation between the sagittal and frontal alignment and possible postural asymmetries found in patients submitted to total knee stent placement for osteosarcoma.Methods:Twenty two individuals were divided into two groups according to tumor location: femur group (13 patients) and tibia group (nine patients), who were evaluated through postural analysis software (SAPO).Results:No statistically significant difference was found between groups, supporting previous result showing that both groups present the same postural asymmetries.Conclusion:We conclude that both groups have the same postural imbalances, especially the knee of the affected limb that presents hyperextension and center of gravity shifted anteriorly and laterally to the non-affected limb, indicating changes in weight bearing and influencing the gait pattern and balance. Level of Evidence II, Prospective Comparative Study.Universidade Federal de São Paulo (UNIFESP) Instituto de Oncologia PediátricaUNIFESP, Instituto de Oncologia PediátricaSciEL
Dynamical Boson Stars
The idea of stable, localized bundles of energy has strong appeal as a model
for particles. In the 1950s John Wheeler envisioned such bundles as smooth
configurations of electromagnetic energy that he called {\em geons}, but none
were found. Instead, particle-like solutions were found in the late 1960s with
the addition of a scalar field, and these were given the name {\em boson
stars}. Since then, boson stars find use in a wide variety of models as sources
of dark matter, as black hole mimickers, in simple models of binary systems,
and as a tool in finding black holes in higher dimensions with only a single
killing vector. We discuss important varieties of boson stars, their dynamic
properties, and some of their uses, concentrating on recent efforts.Comment: 79 pages, 25 figures, invited review for Living Reviews in
Relativity; major revision in 201
Pneumonia necrosante em crianças submetidas à toracoscopia por empiema pleural: incidência, tratamento e evolução clínica
Barn Owl pellets (Aves: Tyto furcata) reveal a higher mammalian richness in the Restinga de Jurubatiba National Park, Southeastern Brazil
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