Baculovirus diversity and its effect on virulence.

The baculovirus, SpexNPV is the biggest mortality agent of natural populations of the African armyworm, Spodoptera exempta and in terms of control has displayed considerable potential as a bioinsecticide in aerial spray trials undertaken by Natural Resources International (NRI). This project was charged with assessing the diversity of natural populations of SpexNPV, a subject of direct relevance for the development of SpexNPV as a bioinsecticde and about which little was known. The genetic composition of a natural SpexNPV population was characterized using in vivo cloning techniques and RFLP analysis. Seventeen individual genotypes were isolated from the wild-type population and phylogenetic analysis was carried out to attempt to assess their potential relatedness, but no single conclusion on their shared histories could be reached. The fitness traits (pathogenicity, speed of kill and viral yield of OBs) of eight genotypes and the wild-type virus were assessed in laboratory bioassays. A nine-fold difference in pathogenicity (estimated in terms of LD50) was witnessed between the different genotypes. Genotypes and wild-type virus also varied in their speed of kill and yield and although there was evidence of a trade-off between speed of kill and yield trade-off, for a number of the genotypes, this study failed to demonstrate any statistical evidence for a general trade-off between these fitness traits. SpexNPV epizootics, from out-breaking populations of armyworm in Northern Tanzania, were sampled in 2002 and 2004. RFLP analysis was conducted on individual virus-infected larvae and revealed a high level of heterogeneity. In addition, forty percentage of all isolates analysed were identified as mixed-genotype infections by the presence of sub-molar bands in RE profiles. This genetic diversity appeared to lack any obvious population structure. Controlled mixed-genotype inoculations were carried out to assess any change in phenotype relative to single-genotype infections. Genotypes, which were found to be equally pathogenic in single-genotype infections, were combined in equal ratio. Thirteen different dual inoculations were carried out across a range of doses. Mixedgenotype infections were found to be more pathogenic, and in general, possess longer speeds of kill relative to single genotype infections. The effect on yield varied considerably between mixtures. The inclusion of more than two genotypes within the mixtures (2-, 4-, 8-, and 16-genotype inoculations) revealed a correlation between level of diversity and pathogenicity and, to a certain extent, between level of diversity and speed of kill. This appears to suggest that mixed-infections possess higher levels of fitness than single genotype infections and that genetic diversity of SpexNPV should be maintained when used as a bioinsecticide

Magical and Mysterious Resonances: Structural Principles in E. T. A. Hoffmann\u27s Kreisler Works and Robert Schumann\u27s Kreisleriana

Robert Schumann\u27s Kreisleriana, Op. 16 (1838), borrows its title from E. T. A. Hoffmann\u27s set of essays concerning his literary alter ego, Johannes Kreisler. The character of Kreisler is most prominently featured in two of Hoffmann\u27s works: the Kreisleriana essays (1814-1815) and his final novel, The Life and Opinions of the Tomcat Murr (1820-1822). This thesis explores the influence of E. T. A. Hoffmann on Schumann\u27s Kreisleriana, focusing on how structural principles derived from Hoffmann\u27s Kreisler works--duality, creating and blurring boundaries, fragmentation and irresolution, and circularity--are at work in Schumann\u27s composition. While others have treated the relationship between Schumann\u27s Kreisleriana and the prose literature programmatically, drawing connections between specific passages in the music and the stories, this thesis discusses how the nature of the influence may be better understood through structural principles such as these

The emergence of resistance to the benzimidazole anthlemintics in parasitic nematodes of livestock is characterised by multiple independent hard and soft selective sweeps

Anthelmintic resistance is a major problem for the control of parasitic nematodes of livestock and of growing concern for human parasite control. However, there is little understanding of how resistance arises and spreads or of the “genetic signature” of selection for this group of important pathogens. We have investigated these questions in the system for which anthelmintic resistance is most advanced; benzimidazole resistance in the sheep parasites Haemonchus contortus and Teladorsagia circumcincta. Population genetic analysis with neutral microsatellite markers reveals that T. circumcincta has higher genetic diversity but lower genetic differentiation between farms than H. contortus in the UK. We propose that this is due to epidemiological differences between the two parasites resulting in greater seasonal bottlenecking of H. contortus. There is a remarkably high level of resistance haplotype diversity in both parasites compared with drug resistance studies in other eukaryotic systems. Our analysis suggests a minimum of four independent origins of resistance mutations on just seven farms for H. contortus, and even more for T. circumincta. Both hard and soft selective sweeps have occurred with striking differences between individual farms. The sweeps are generally softer for T. circumcincta than H. contortus, consistent with its higher level of genetic diversity and consequent greater availability of new mutations. We propose a model in which multiple independent resistance mutations recurrently arise and spread by migration to explain the widespread occurrence of resistance in these parasites. Finally, in spite of the complex haplotypic diversity, we show that selection can be detected at the target locus using simple measures of genetic diversity and departures from neutrality. This work has important implications for the application of genome-wide approaches to identify new anthelmintic resistance loci and the likelihood of anthelmintic resistance emerging as selection pressure is increased in human soil-transmitted nematodes by community wide treatment programs

Environmental constraints on the use of anion exchange membranes in dryland wheat

Lack of growing season precipitation and the temperate climate in north central Oregon pose challenges to growing spring wheat crops. Phosphate and sulfate fertilization can improve early growth of spring wheat in this region and soil testing aids in determining rates of fertilization. In this study, anion exchange membranes (AEM) were used to assess phosphorus and sulfur supply rates in four, minimally-tilled, annually cropped spring wheat fields in north central Oregon. To determine the validity of AEM in this region, uptake of P and S by hard red spring (HRS) wheat was correlated with soil supply of P and S as predicted by AEM. I found that in low soil water content and cool soil temperature conditions, AEM did not accurately measure plant available P and S. Unlike plants, AEM are static instruments that cannot measure plant available nutrients when soil conditions limit mineralization and diffusion of plant nutrients. I also found that three consecutive years of drought across the study sites has led to P and S quantities sufficient for maximum yield potential of HRS wheat without fertilization. These results suggest that growers in north central Oregon may not necessarily need to fertilize wheat crops following a drought and that AEM may provide inaccurate information regarding soil nutrient status

Socio‑cultural implications for women’s menstrual health in the Pacific Island Countries and Territories (PICTs): a scoping review

Background: Globally, experiences of menarche and subsequent menstruation are embedded in social and cultural beliefs, norms and practices. Menarche is an important developmental milestone in sexual and reproductive health (SRH) for females. Menarche is intertwined with socio‑cultural norms, beliefs and practices, which can impact on women’s ability to manage menstruation with dignity. This paper reviews the social and cultural factors that affect women’s ability to effectively manage their menstrual health and hygiene (MHH) in Pacific Island Countries and Territories (PICTs). Methods: A scoping review was conducted following PRISMA scoping review guidelines and inclusion/exclusion criteria. An online search was conducted for peer‑reviewed publications in Medline/OVID; Medline/PubMED; PsycINFO; CINAHL; Scopus and JSTOR, and Google Scholar. A search for grey literature was conducted in Google Scholar and websites of international and local organizations. Experts in the field also contributed additional references. Extracted data were summarised in an Excel spreadsheet. Searches were conducted between May and June, 2019, and then repeated in July, 2020. Results: A total of 11 studies were included; 10 qualitative and one mixed methods study. Studies were conducted in Melanesian (n=9), Polynesian (n=1) and Micronesian (n=1) PICTs. All 11 studies reported elements of societal and personal factors; ten studies reported evidence relating to interpersonal factors; nine studies reported elements relating to environmental factors; and two studies presented evidence linked to biological factors. Managing menstrual health with dignity is challenging for many women and girls because menstruation is associated with menstrual taboos and shame. Conclusion: This review found that the MHH experiences of women in PICTs are affected by social and cultural beliefs, norms and practices. Beliefs, norms and practices about menarche need to be incorporated in SRH planning, programs and education in order to be relevant to diverse village and urban settings

'Making of a strong woman': a constructivist grounded theory of the experiences of young women around menarche in Papua New Guinea

Background: Menarche, the first menstruation, is a significant developmental milestone for females. In Papua New Guinea (PNG), menarche is an important socio-cultural event marking transition from girlhood to womanhood. PNG is a culturally and linguistically diverse nation, with wide-ranging socio-cultural beliefs and practices around menarche. This study explored post-menarcheal women’s understanding about body changes and menarche, preparation for menarche, and related cultural beliefs and practices at menarche. Methods: A constructivist grounded theory study was conducted with 98 female participants who originated from four PNG provinces: Eastern Highlands Province; East Sepik Province; Milne Bay Province; and National Capital District. The participants were purposively and theoretically sampled, with 10 focus group discussions and six individual interviews conducted using a semi-structured interview guide for data collection. Focus group discussions and interviews were voice recorded and transcribed. Data were inductively analyzed using initial, intermediate and advanced coding, memos and constant comparative methods to develop a theoretical model that explains women’s experiences at menarche. Interview participants also identified actions required to improve future experiences of girls at menarche in PNG. Results: A grounded theory comprising the core category of ‘Making of a Strong Woman’ and four interconnecting categories (‘Having Baby Sense’; ‘Beginning of Learning’; ‘Intensifying Learning’; and ‘Achieving Womanhood’) was constructed. ‘Urban’ and ‘Rural’ represented both geographical and socio-cultural intervening conditions that influence the experiences of girls at menarche. Experiences of young women at menarche were rooted in socio-cultural beliefs and practices. Women reported being physically and emotionally distressed and unprepared at onset of menarche. Mothers were considered important support, however, their ability to adequately prepare their daughters is limited by shame and secrecy. Despite these limitations, cultural practices at menarche provided an opportunity for intensive preparation of girls for womanhood. Conclusion: Limited pre-menarcheal awareness of the meaning of body changes and menarche of girls was linked to culture of shame and secrecy about open discussion on sexuality. However, traditional cultural practices provide an opportunity for collective support and focused learning for girls. Findings from this study have implications for broader sexual and reproductive health education programs in addressing menstrual health and hygiene in PNG, and the Pacific

A method for single pair mating in an obligate parasitic nematode

Parasitic nematode species have extremely high levels of genetic diversity, presenting a number of experimental challenges for genomic and genetic work. Consequently, there is a need to develop inbred laboratory strains with reduced levels of polymorphism. The most efficient approach to inbred line development is single pair mating, but this is challenging for obligate parasites where the adult sexual reproductive stages are inside the host, and thus difficult to experimentally manipulate. This paper describes a successful approach to single pair mating of a parasitic nematode, Haemonchus contortus. The method allows for polyandrous mating behaviour and involves the surgical transplantation of a single adult male worm with multiple immature adult females directly into the sheep abomasum. We used a panel of microsatellite markers to monitor and validate the single pair mating crosses and to ensure that the genotypes of progeny and subsequent filial generations were consistent with those expected from a mating between a single female parent of known genotype and a single male parent of unknown genotype. We have established two inbred lines that both show a significant overall reduction in genetic diversity based on microsatellite genotyping and genome-wide single nucleotide polymorphism. There was an approximately 50% reduction in heterozygous SNP sites across the genome in the MHco3.N1 line compared with the MoHco3(ISE) parental strain. The MHco3.N1 inbred line has subsequently been used to provide DNA template for whole genome sequencing of H. contortus. This work provides proof of concept and methodologies for forward genetic analysis of obligate parasitic nematodes

The confounding effects of high genetic diversity on the determination and interpretation of differential gene expression analysis in the parasitic nematode Haemonchus contortus

Differential expression analysis between parasitic nematode strains is commonly used to implicate candidate genes in anthelmintic resistance or other biological functions. We have tested the hypothesis that the high genetic diversity of an organism such as Haemonchus contortus could complicate such analyses. First, we investigated the extent to which sequence polymorphism affects the reliability of differential expression analysis between the genetically divergent H. contortus strains MHco3(ISE), MHco4(WRS) and MHco10(CAVR). Using triplicates of 20 adult female worms from each population isolated under parallel experimental conditions, we found that high rates of sequence polymorphism in RNAseq reads were associated with lower efficiency read mapping to gene models under default TopHat2 parameters, leading to biased estimates of inter-strain differential expression. We then showed it is possible to largely compensate for this bias by optimising the read mapping single nucleotide polymorphism (SNP) allowance and filtering out genes with particularly high single nucleotide polymorphism rates. Once the sequence polymorphism biases were removed, we then assessed the genuine transcriptional diversity between the strains, finding ≥824 differentially expressed genes across all three pairwise strain comparisons. This high level of inter-strain transcriptional diversity not only suggests substantive inter-strain phenotypic variation but also highlights the difficulty in reliably associating differential expression of specific genes with phenotypic differences. To provide a practical example, we analysed two gene families of potential relevance to ivermectin drug resistance; the ABC transporters and the ligand-gated ion channels (LGICs). Over half of genes identified as differentially expressed using default TopHat2 parameters were shown to be an artifact of sequence polymorphism differences. This work illustrates the need to account for sequence polymorphism in differential expression analysis. It also demonstrates that a large number of genuine transcriptional differences can occur between H. contortus strains and these must be considered before associating the differential expression of specific genes with phenotypic differences between strains