881 resultados para Mitochondrial inheritance
Resumo:
This paper develops a framework of risk and protective factors to conceptualise the relationship between HIV-related stigma, asset inheritance and chronic poverty among widows and caregiving children and youth in eastern Africa. Analysis of two qualitative studies with 85 participants in rural and urban areas of Tanzania and Uganda reveals that gendered and generational inequalities and stigmatisation sometimes led to property grabbing and chronic poverty. Human and social capital and preventative measures however may help widows and caregiving young people in HIV-affected households to safeguard land and other assets, within a wider supportive environment that seeks to tackle structural inequalities.
Resumo:
Age-related decline in the integrity of mitochondria is an important contributor to the human ageing process. In a number of ageing stem cell populations, this decline in mitochondrial function is due to clonal expansion of individual mitochondrial DNA (mtDNA) point mutations within single cells. However the dynamics of this process and when these mtDNA mutations occur initially are poorly understood. Using human colorectal epithelium as an exemplar tissue with a well-defined stem cell population, we analysed samples from 207 healthy participants aged 17-78 years using a combination of techniques (Random Mutation Capture, Next Generation Sequencing and mitochondrial enzyme histochemistry), and show that: 1) non-pathogenic mtDNA mutations are present from early embryogenesis or may be transmitted through the germline, whereas pathogenic mtDNA mutations are detected in the somatic cells, providing evidence for purifying selection in humans, 2) pathogenic mtDNA mutations are present from early adulthood (<20 years of age), at both low levels and as clonal expansions, 3) low level mtDNA mutation frequency does not change significantly with age, suggesting that mtDNA mutation rate does not increase significantly with age, and 4) clonally expanded mtDNA mutations increase dramatically with age. These data confirm that clonal expansion of mtDNA mutations, some of which are generated very early in life, is the major driving force behind the mitochondrial dysfunction associated with ageing of the human colorectal epithelium.
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This article explores the role of women's inheritance and ownership of property in urban Senegal. It shows how being able to inherit and own property promotes the economic and emotional security of widows and their children in urban areas, and discusses the challenges posed by legal pluralism in working on poverty alleviation and social protection in the city.
Resumo:
Although women's land rights are often affirmed unequivocally in constitutions and international human rights conventions in many African countries, customary practices usually prevail on the ground and often deny women's land inheritance. Yet land inheritance often goes unnoticed in wider policy and development initiatives to promote women's equal access to land. This paper draws on feminist ethnographic research among the Serer ethnic group in two contrasting rural communities in Senegal. Through analysis of land governance, power relations and 'technologies of the self', this article shows how land inheritance rights are contingent on the specific effects of intersectionality in particular places. The contradictions of legal pluralism, greater adherence to Islam and decentralisation led to greater application of patrilineal inheritance practices. Gender, religion and ethnicity intersected with individuals' marital position, status, generation and socio-ecological change to constrain land inheritance rights for women, particularly daughters, and widows who had been in polygamous unions and who remarried. Although some women were aware that they were legally entitled to inherit a share of the land, they tended not to 'demand their rights'. In participatory workshops, micro-scale shifts in women's and men's positionings reveal a recognition of the gender discriminatory nature of customary and Islamic law and a desire to 'change with the times'. While the effects of 'reverse' discourses are ambiguous and potentially reinforce prevailing patriarchal power regimes, 'counter' discourses, which emerged in participatory spaces, may challenge customary practices and move closer to a rights-based approach to gender equality and women's land inheritance.
Resumo:
Cardiac myocyte apoptosis is potentially important in many cardiac disorders. In other cells, Bcl-2 family proteins and mitochondrial dysfunction are probably key regulators of the apoptotic response. In the present study, we characterized the regulation of antiapoptotic (Bcl-2, Bcl-xL) and proapoptotic (Bad, Bax) Bcl-2 family proteins in the rat heart during development and in oxidative stress-induced apoptosis. Bcl-2 and Bcl-xL were expressed at high levels in the neonate, and their expression was sustained during development. In contrast, although Bad and Bax were present at high levels in neonatal hearts, they were barely detectable in adult hearts. We confirmed that H(2)O(2) induced cardiac myocyte cell death, stimulating poly(ADP-ribose) polymerase proteolysis (from 2 hours), caspase-3 proteolysis (from 2 hours), and DNA fragmentation (from 8 hours). In unstimulated neonatal cardiac myocytes, Bcl-2 and Bcl-xL were associated with the mitochondria, but Bad and Bax were predominantly present in a crude cytosolic fraction. Exposure of myocytes to H(2)O(2) stimulated rapid translocation of Bad (<5 minutes) to the mitochondria. This was followed by the subsequent degradation of Bad and Bcl-2 (from approximately 30 minutes). The levels of the mitochondrial membrane marker cytochrome oxidase remained unchanged. H(2)O(2) also induced translocation of cytochrome c from the mitochondria to the cytosol within 15 to 30 minutes, which was indicative of mitochondrial dysfunction. Myocytes exposed to H(2)O(2) showed an early loss of mitochondrial membrane potential (assessed by fluorescence-activated cell sorter analysis) from 15 to 30 minutes, which was partially restored by approximately 1 hour. However, a subsequent irreversible loss of mitochondrial membrane potential occurred that correlated with cell death. These data suggest that the regulation of Bcl-2 and mitochondrial function are important factors in oxidative stress-induced cardiac myocyte apoptosis.
Resumo:
Species of the genus Culex Linnaeus have been incriminated as the main vectors of lymphatic filariases and are important vectors of arboviruses, including West Nile virus. Sequences corresponding to a fragment of 478 bp of the cytochrome c oxidase subunit I gene, which includes part of the barcode region, of 37 individuals of 17 species of genus Culex were generated to establish relationships among five subgenera, Culex, Phenacomyia, Melanoconion, Microculex, and Carrollia, and one species of the genus Lutzia that occurs in Brazil. Bayesian methods were employed for the phylogenetic analyses. Results of sequence comparisons showed that individuals identified as Culex dolosus, Culex mollis, and Culex imitator possess high intraspecific divergence (3.1, 2.3, and 3.5%, respectively) when using the Kimura two parameters model. These differences were associated either with distinct morphological characteristics of the male genitalia or larval and pupal stages, suggesting that these may represent species complexes. The Bayesian topology suggested that the genus and subgenus Culex are paraphyletic relative to Lutzia and Phenacomyia, respectively. The cytochrome c oxidase subunit I sequences may be a useful tool to both estimate phylogenetic relationships and identify morphologically similar species of the genus Culex.
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Phylogenetic relationships among 21 species of mosquitoes in subgenus Nyssorhynchus were inferred from the nuclear white and mitochondrial NADH dehydrogenase subunit 6 (ND6) genes. Bayestan phylogenetic methods found that none of the three Sections within Nyssorhynchus (Albimanus, Argyritarsis, Myzorhynchella) were supported in all analyses, although Myzorhynchella was found to be monophyletic at the combined genes Within the Albimanus Section the monophyly of the Stroder Subgroup was strongly supported and within the Myzorhynchella Section Anopheles anrunesi and An lutzu formed a strongly supported monophyletic group The epidemiologically significant Albitarsis Complex showed evidence of paraphyly (relative to An lanet-Myzorhynchella) and discordance across gene trees, and the previously synonomized species of An. dunhami and An goeldii were recovered as sister species Finally, there was evidence of complexes in several species, including An antunesi, An deaneorum, and An. strodei (c) 2010 Elsevier B.V. All rights reserved
Resumo:
The extensive replication of mitochondria during oogenesis and the wide variability in mitochondrial DNA ( mtDNA) copy numbers present in fully grown oocytes indicate that mtDNA amount may play an important role during early embryogenesis. Using bovine oocytes derived from follicles of different sizes to study the influence of mtDNA content on development, we showed that oocytes obtained from small follicles, known to be less competent in developing into blastocysts, contain less mtDNA than those originating from larger follicles. However, because of the high variability in copy number, a more accurate approach was examined in which parthenogenetic one-cell embryos were biopsied to measure their mtDNA content and then cultured to assess development capacity. Contrasting with previous findings, mtDNA copy number in biopsies was not different between competent and incompetent embryos, indicating that mtDNA content is not related to early developmental competence. To further examine the importance of mtDNA on development, one-cell embryos were partially depleted of their mtDNA (64% +/- 4.1% less) by centrifugation followed by the removal of the mitochondrial-enriched cytoplasmic fraction. Surprisingly, depleted embryos developed normally into blastocysts, which contained mtDNA copy numbers similar to nonmanipulated controls. Development in depleted embryos was accompanied by an increase in the expression of genes (TFAM and NRF1) controlling mtDNA replication and transcription, indicating an intrinsic ability to restore the content of mtDNA at the blastocyst stage. Therefore, we concluded that competent bovine embryos are able to regulate their mtDNA content at the blastocyst stage regardless of the copy numbers accumulated during oogenesis.
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Oculoauriculovertebral spectrum (OAVS; OMIM 164210) is a complex condition characterized by defects of aural, oral, mandibular and vertebral development. The aetiology of this condition is likely to be heterogeneous; most cases are sporadic, however, familial cases suggesting autosomal recessive end autosomal dominant inheritance have been reported. In this study, we describe the clinical aspects of nine familial cases with evidence of autosomal dominant inheritance and compare them with reports in the literature. Interfamilial and intrafamilial clinical variabilities were observed in this study (reinforcing the necessity of careful examination of familial members). We suggest that oculoauriculovertebral spectrum with autosomal dominant inheritance is characterized mainly by bilateral auricular involvement and rarely presents extracranial anomalies. Clin Dysmorphol 18:67-77 (C) 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins.