674 research outputs found

    Functional interaction between Epstein-Barr virus replication protein Zta and host DNA damage response protein 53BP1

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    Epstein-Barr virus (EBV; human herpesvirus 4) poses major clinical problems worldwide. Following primary infection, EBV enters a form of long-lived latency in B lymphocytes, expressing few viral genes, and it persists for the lifetime of the host with sporadic bursts of viral replication. The switch between latency and replication is governed by the action of a multifunctional viral protein Zta (also called BZLF1, ZEBRA, and Z). Using a global proteomic approach, we identified a host DNA damage repair protein that specifically interacts with Zta: 53BP1. 53BP1 is intimately connected with the ATM signal transduction pathway, which is activated during EBV replication. The interaction of 53BP1 with Zta requires the C-terminal ends of both proteins. A series of Zta mutants that show a wild-type ability to perform basic functions of Zta, such as dimer formation, interaction with DNA, and the transactivation of viral genes, were shown to have lost the ability to induce the viral lytic cycle. Each of these mutants also is compromised in the C-terminal region for interaction with 53BP1. In addition, the knockdown of 53BP1 expression reduced viral replication, suggesting that the association between Zta and 53BP1 is involved in the viral replication cycle

    Genomic signatures of inbreeding depression for a threatened Aotearoa New Zealand passerine

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    For small and isolated populations, the increased chance of mating between related individuals can result in a substantial reduction in individual and population fitness. Despite the increasing availability of genomic data to measure inbreeding accurately across the genome, inbreeding depression studies for threatened species are still scarce due to the difficulty of measuring fitness in the wild. Here, we investigate inbreeding and inbreeding depression for the extensively monitored Tiritiri Mātangi island population of a threatened Aotearoa New Zealand passerine, the hihi (Notiomystis cincta). First, using a custom 45 k single nucleotide polymorphism (SNP) array, we explore genomic inbreeding patterns by inferring homozygous segments across the genome. Although all individuals have similar levels of ancient inbreeding, highly inbred individuals are affected by recent inbreeding, which can probably be explained by bottleneck effects such as habitat loss after European arrival and their translocation to the island in the 1990s. Second, we investigate genomic inbreeding effects on fitness, measured as lifetime reproductive success, and its three components, juvenile survival, adult annual survival and annual reproductive success, in 363 hihi. We find that global inbreeding significantly affects juvenile survival but none of the remaining fitness traits. Finally, we employ a genome-wide association approach to test the locus-specific effects of inbreeding on fitness, and identify 13 SNPs significantly associated with lifetime reproductive success. Our findings suggest that inbreeding depression does impact hihi, but at different genomic scales for different traits, and that purging has therefore failed to remove all variants with deleterious effects from this population of conservation concern

    Assembly of female and male hihi genomes (stitchbird; Notiomystis cincta) enables characterization of the W chromosome and resources for conservation genomics

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    A high-quality reference genome can be a valuable resource for threatened species by providing a foundation to assess their evolutionary potential to adapt to future pressures such as environmental change. We assembled the genome of a female hihi (Notiomysits cincta), a threatened passerine bird endemic to Aotearoa New Zealand. The assembled genome is 1.06 Gb, and is of high quality and highly contiguous, with a contig N50 of 7.0 Mb, estimated QV of 44 and a BUSCO completeness of 96.8%. A male assembly of comparable quality was generated in parallel. A population linkage map was used to scaffold the autosomal contigs into chromosomes. Female and male sequence coverage and comparative genomics analyses were used to identify Z-, and W-linked contigs. In total, 94.6% of the assembly length was assigned to putative nuclear chromosome scaffolds. Native DNA methylation was highly correlated between sexes, with the W chromosome contigs more highly methylated than autosomal chromosomes and Z contigs. 43 differentially methylated regions were identified, and these may represent interesting candidates for the establishment or maintenance of sex differences. By generating a high-quality reference assembly of the heterogametic sex, we have created a resource that enables characterization of genome-wide diversity and facilitates the investigation of female-specific evolutionary processes. The reference genomes will form the basis for fine-scale assessment of the impacts of low genetic diversity and inbreeding on the adaptive potential of the species and will therefore enable tailored and informed conservation management of this threatened taonga (treasured) species

    A silent orchestra: convergent song loss in Hawaiian crickets is repeated, morphologically varied, and widespread

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    Host-parasite interactions are predicted to drive the evolution of defences and counter-defences, but the ability of either partner to adapt depends on new and advantageous traits arising. The loss of male song in Hawaiian field crickets (Teleogryllus oceanicus) subject to fatal parasitism by eavesdropping flies (Ormia ochracea) is a textbook example of rapid evolution in one such arms race. Male crickets ordinarily sing to attract females by rubbing their forewings together, which produces sound by exciting acoustic resonating structures formed from modified wing veins (‘normal-wing’). The resulting song is the target of strong sexual selection by conspecific females. However, male song also attracts female flies that squirt larvae onto males or nearby female crickets; the larvae then burrow into, consume, and ultimately kill the host. The flies thus impose strong natural selection on male song, producing silent males, which have spread rapidly in populations on two islands – Kauai and Oahu. On both islands, song loss is caused by genetic mutations that drastically reduce or eliminate sound-producing structures on the male forewing by feminising wing venation – these males are called ‘flatwing’. On recent visits to parasitized cricket populations, we discovered two additional wing phenotypes – ‘small-wing’ and ‘curly-wing’. These two phenotypes differ noticeably from flatwing, and from each other, but all have the effect of eliminating or reducing acoustic signals that attract the parasitoid fly. These discoveries illustrate how the evolutionary process can repeatedly, and through a remarkable variety of independent mechanisms, drive adaptation to the same selection pressure

    Overcoming barriers to engagement and adherence to a home-based physical activity intervention for patients with heart failure:a qualitative focus group study

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    Clinical guidelines recommend regular physical activity for patients with heart failure to improve functional capacity and symptoms and to reduce hospitalisation. Cardiac rehabilitation programmes have demonstrated success in this regard; however, uptake and adherence are suboptimal. Home-based physical activity programmes have gained popularity to address these issues, although it is acknowledged that their ability to provide personalised support will impact on their effectiveness. This study aimed to identify barriers and facilitators to engagement and adherence to a home-based physical activity programme, and to identify ways in which it could be integrated into the care pathway for patients with heart failure. A qualitative focus group study was conducted. Data were analysed using thematic analysis. A purposive sample of 16 patients, 82% male, aged 68±7 years, with heart failure duration of 10±9 years were recruited. A 12-week behavioural intervention targeting physical activity was delivered once per week by telephone. Ten main themes were generated that provided a comprehensive overview of the active ingredients of the intervention in terms of engagement and adherence. Fear of undertaking physical activity was reported to be a significant barrier to engagement. Influences of family members were both barriers and facilitators to engagement and adherence. Facilitators included endorsement of the intervention by clinicians knowledgeable about physical activity in the context of heart failure; ongoing support and personalised feedback from team members, including tailoring to meet individual needs, overcome barriers and increase confidence. Endorsement of interventions by clinicians to reduce patients' fear of undertaking physical activity and individual tailoring to overcome barriers are necessary for long-term adherence. Encouraging family members to attend consultations to address misconceptions and fear about the contraindications of physical activity in the context of heart failure should be considered for adherence, and peer-support for long-term maintenance. NCT03677271. [Abstract copyright: © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY. Published by BMJ.

    "After my husband's circumcision, I know that I am safe from diseases": Women's Attitudes and Risk Perceptions Towards Male Circumcision in Iringa, Tanzania.

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    While male circumcision reduces the risk of female-to-male HIV transmission and certain sexually transmitted infections (STIs), there is little evidence that circumcision provides women with direct protection against HIV. This study used qualitative methods to assess women's perceptions of male circumcision in Iringa, Tanzania. Women in this study had strong preferences for circumcised men because of the low risk perception of HIV with circumcised men, social norms favoring circumcised men, and perceived increased sexual desirability of circumcised men. The health benefits of male circumcision were generally overstated; many respondents falsely believed that women are also directly protected against HIV and that the risk of all STIs is greatly reduced or eliminated in circumcised men. Efforts to engage women about the risks and limitations of male circumcision, in addition to the benefits, should be expanded so that women can accurately assess their risk of HIV or STIs during sexual intercourse with circumcised men

    The rise of policy coherence for development: a multi-causal approach

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    In recent years policy coherence for development (PCD) has become a key principle in international development debates, and it is likely to become even more relevant in the discussions on the post-2015 sustainable development goals. This article addresses the rise of PCD on the Western donors’ aid agenda. While the concept already appeared in the work of Organisation for Economic Co-operation and Development (OECD) in the early 1990s, it took until 2007 before PCD became one of the Organisation’s key priorities. We adopt a complexity-sensitive perspective, involving a process-tracing analysis and a multi-causal explanatory framework. We argue that the rise of PCD is not as contingent as it looks. While actors such as the EU, the DAC and OECD Secretariat were the ‘active causes’ of the rise of PCD, it is equally important to look at the underlying ‘constitutive causes’ which enabled policy coherence to thrive well
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