Investigations on the Tobacco necrosis virus D p60 replicase protein

Copyright: © 2013 Fang, Coutts. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedTobacco necrosis virus D (TNV-D), in the genus Betanecrovirus (family Tombusviridae), possesses a single-stranded, positive-sense RNA genome containing six open reading frames (ORFs). Two 5'-proximal ORFs (1 and 2) encode overlapping polypeptides of 22 and 82 kDa (p22 and p82, respectively) which are both required for replication. The p22 auxiliary protein contains no replication motifs but the C-terminal region, downstream of a leaky stop codon, encodes a 60 kDa polypeptide (p60) which contains conserved RNA-dependent RNA polymerase (RdRP) motifs. Here we have expressed and purified recombinant p60 and show that in vitro it binds and efficiently synthesises both TNV-D RNA and Satellite tobacco necrosis virus C RNA. Alanine scanning mutagenesis of conserved amino acids in characteristic motifs in p60 revealed that some mutations significantly reduced RNA synthesis but mutating the second asparagine residue in the conserved GDD box was lethal. The effects of mutating identical amino acids in p60 on virus replication in vivo were examined in Nicotiana benthamiana plants following infection with RNA transcribed from wild type (wt) and mutant constructs. In inoculated leaves the behaviour of the mutants paralleled the in vitro data but systemic infection was precluded in all but one mutant which had reverted to wt. This study is the first to demonstrate the nucleic acid-binding and synthetic capabilities of a betanecrovirus polymerasePeer reviewe

Breast cancer and screening prevention programmes : perceptions of women in a multicultural community in southern Thailand

Background: Breast cancer is a leading cause of morbidity and mortality among women worldwide and in Thailand. Objective: To explore perceptions of breast cancer and screening prevention programmes among a group of at-risk women in a multicultural setting in southern Thailand. Methods: Semi-structured in-depth interviews were used for data collection with 30 at-risk group women. Women from Muslim and Buddhist backgrounds were purposively included in this study. The thematic analysis method was used to analyse the data. Results: Four themes were identified from our data: perceptions of breast cancer, being diagnosed with breast cancer and anxiety, stigma: effects of breast cancer, and breast self-screening and prevention of breast cancer. The participants had some knowledge about the risk factors for breast cancer. However, participants perceived that breast cancer could occur to individual women at any time and that it was not possible to entirely prevent the disease, even when following a breast self-examination programme. However, most participants perceived that whether one would be afflicted by breast cancer depended also on Allah and their own karma. All participants were encouraged to attend breast self-screening training by healthcare providers of local health centres, but they had no confidence to perform self-screening soon after finishing the training programme. This became the reason for a lack of regular self-screening with responsibility left to health practitioners. Although participants were aware that breast self-screening should be their routine practice, there were multiple barriers to this, including accurate knowledge about breast cancer, belief, self-awareness, screening skills and healthcare facilities. Breast self-screening was recognised as an important means of early detection. However, most women did not perform this regularly, which could increase their risk of developing breast cancer. Conclusions: Public health providers need to be more concerned about the perceptions, beliefs and practices regarding breast cancer and develop prevention practices that work better for women living in more diverse cultural locations so that they may be able to follow preventive practices and reduce their vulnerability to breast cancer