Molecular determinants of bacterial colonisation on macroalgal surfaces

Macroalgae, the ecosystem engineers of temperate marine habitats, are particularly vulnerable to climate change. Environmental stress is linked to a decline in macroalgal health and can render the host susceptible to attack by opportunistic pathogens. Bacteria form an important part of the macroalgal holobiont; however, bacterial pathogens are also major contributors to disease in macroalgae. Despite the importance of bacterial interactions with macroalgal hosts, there remains a paucity of knowledge regarding the molecular mechanisms that facilitate bacterial colonisation in this context. The aim of work conducted in this thesis was to investigate the molecular mechanisms that facilitate bacterial colonisation and persistence on macroalgae using two model systems- the red alga Delisea pulchra and the green alga Ulva autsralis. Increased sea surface temperatures reduce the host defence capacity of D. pulchra, and increase the susceptibility of the macroalga to infection by opportunistic pathogens, including the Roseobacter species, Nautella sp. R11. This research utilised molecular techniques, including allelic exchange mutagenesis and quantitative proteomics, in combination with attachment assays and colonisation experiments to identify molecular factors that contribute to the virulence of Nautella sp. R11. This is the first study to elucidate a role for the stress-resistance enzyme, glutathione peroxidase, and two cell density dependant transcriptional regulators (VarR and RaiR) in mediating virulence in a macroalgal pathogen. The second model system focused on the mechanisms utilised by the bacterium Pseudoalteromonas tunicata to competitively colonise the surface of U. australis. The study identified a role for the P. tunicata lipoprotein, PtlL32, in mediating the interaction between the bacterial epibiont and its host macroalga. This work provides the first evidence of a role for LipL32 outside of the human pathogen, Leptospira interrogans, where the protein facilitates attachment to mammalian extracellular matrix factors. The work presented in this thesis builds upon the previously limited understanding of the molecular factors that facilitate bacterial colonisation on macroalgae and provides insight into the dual-function characteristics that confer virulence in environmental bacteria

Defining Young in the Context of Prostate Cancer

The experience of prostate cancer is for most men a major life stress with the psychological burden of this disease falling more heavily on those who are younger. Despite this, being young as it applies to prostate cancer is not yet clearly defined with varied chronological approaches applied. However, men’s responses to health crises are closely bound to life course and masculinities from which social roles emerge. This paper applied qualitative methodology (structured focus groups and semistructured interviews with expert informants) using interpretative phenomenological analysis to define what it means to be young and have prostate cancer. Structured focus groups were held with 26 consumer advisors (men diagnosed with prostate cancer who provide support to other men with prostate cancer or raise community awareness) and health professionals. As well, 15 men diagnosed with prostate cancer and in their 40s, 50s, or 60s participated in semi-structured interviews. Participants discussed the attributes that describe a young man with prostate cancer and the experience of being young and diagnosed with prostate cancer. Chronological definitions of a young man were absent or inconsistent. Masculine constructions of what it means to be a young man and life course characteristics appear more relevant to defining young as it applies to prostate cancer compared with chronological age. These findings have implications for better understanding the morbidities associated with this illness, and in designing interventions that are oriented to life course and helping young men reconstruct their identities after prostate cancer

Defining young in the context of prostate cancer

The experience of prostate cancer is for most men a major life stress with the psychological burden of this disease falling more heavily on those who are younger. Despite this, being young as it applies to prostate cancer is not yet clearly defined with varied chronological approaches applied. However, men’s responses to health crises are closely bound to life course and masculinities from which social roles emerge. This paper applied qualitative methodology (structured focus groups and semistructured interviews with expert informants) using interpretative phenomenological analysis to define what it means to be young and have prostate cancer. Structured focus groups were held with 26 consumer advisors (men diagnosed with prostate cancer who provide support to other men with prostate cancer or raise community awareness) and health professionals. As well, 15 men diagnosed with prostate cancer and in their 40s, 50s, or 60s participated in semi-structured interviews. Participants discussed the attributes that describe a young man with prostate cancer and the experience of being young and diagnosed with prostate cancer. Chronological definitions of a young man were absent or inconsistent. Masculine constructions of what it means to be a young man and life course characteristics appear more relevant to defining young as it applies to prostate cancer compared with chronological age. These findings have implications for better understanding the morbidities associated with this illness, and in designing interventions that are oriented to life course and helping young men reconstruct their identities after prostate cancer

Transnational Criminal Law or the Transnational Legal Ordering of Corruption?

To date, “transnational criminal law” has been the dominant paradigm for explaining and mapping rules on corruption in the international legal literature. Transnational criminal law is presented as a system of law descending from multilateral crime control treaties or a field or order that emerges through international political processes of regime formation. Transnational criminal lawyers identify and describe cross-border legal rules, and seek to evaluate them against liberal norms of democratic governance and individual civil and political human rights. This Article details the limits of transnational criminal conceptions of “anticorruption” through a study of proposed changes to Australian laws on corporate foreign bribery. Drawing on primary and secondary documentary sources, domestic and international, it shows that the emerging antipodean rules are only partially transnational, as that term is understood in transnational criminal law theory. Likewise, multilateral “suppression conventions” and related soft laws are but one impetus for the proposed changes to Australian federal anticorruption legislation. Rather, as the transnational legal ordering literature suggests, a recursive process appears to be at work between international organizations and local legislators, as well as transnational non-state actors, both charities and businesses. This process is marked by moments of borrowing from (former) patrons, the US and the UK. However, it is also punctuated by themes of modernization, economic efficiency, and reputation. In addition, Australian anti-corruption activities may result not just in changes to national criminal law, but also in the development of “new” – and controversial – techniques of governance

Loss of GPVI and GPIbα contributes to trauma-induced platelet dysfunction in severely injured patients

Trauma-induced coagulopathy (TIC) is a complex, multifactorial failure of hemostasis that occurs in 25% of severely injured patients and results in a fourfold higher mortality. However, the role of platelets in this state remains poorly understood. We set out to identify molecular changes that may underpin platelet dysfunction after major injury and to determine how they relate to coagulopathy and outcome. We performed a range of hemostatic and platelet-specific studies in blood samples obtained from critically injured patients within 2 hours of injury and collected prospective data on patient characteristics and clinical outcomes. We observed that, although platelet counts were preserved above critical levels, circulating platelets sampled from trauma patients exhibited a profoundly reduced response to both collagen and the selective glycoprotein VI (GPVI) agonist collagen-related peptide, compared with those from healthy volunteers. These responses correlated closely with overall clot strength and mortality. Surface expression of the collagen receptors GPIbα and GPVI was reduced on circulating platelets in trauma patients, with increased levels of the shed ectodomain fragment of GPVI detectable in plasma. Levels of shed GPVI were highest in patients with more severe injuries and TIC. Collectively, these observations demonstrate that platelets experience a loss of GPVI and GPIbα after severe injury and translate into a reduction in the responsiveness of platelets during active hemorrhage. In turn, they are associated with reduced hemostatic competence and increased mortality. Targeting proteolytic shedding of platelet receptors is a potential therapeutic strategy for maintaining hemostatic competence in bleeding and improving the efficacy of platelet transfusions

UNBOUND

UNBOUND showcases the graduating class from the fashion design school at Fanshawe College.https://first.fanshawec.ca/famd_design_fashiondesign_unbound/1007/thumbnail.jp

CG dinucleotide clustering is a species-specific property of the genome

Cytosines at cytosine-guanine (CG) dinucleotides are the near-exclusive target of DNA methyltransferases in mammalian genomes. Spontaneous deamination of methylcytosine to thymine makes methylated cytosines unusually susceptible to mutation and consequent depletion. The loci where CG dinucleotides remain relatively enriched, presumably due to their unmethylated status during the germ cell cycle, have been referred to as CpG islands. Currently, CpG islands are solely defined by base compositional criteria, allowing annotation of any sequenced genome. Using a novel bioinformatic approach, we show that CG clusters can be identified as an inherent property of genomic sequence without imposing a base compositional a priori assumption. We also show that the CG clusters co-localize in the human genome with hypomethylated loci and annotated transcription start sites to a greater extent than annotations produced by prior CpG island definitions. Moreover, this new approach allows CG clusters to be identified in a species-specific manner, revealing a degree of orthologous conservation that is not revealed by current base compositional approaches. Finally, our approach is able to identify methylating genomes (such as Takifugu rubripes) that lack CG clustering entirely, in which it is inappropriate to annotate CpG islands or CG clusters

Comparing Aerodynamic Efficiency in Birds and Bats Suggests Better Flight Performance in Birds

Flight is one of the energetically most costly activities in the animal kingdom, suggesting that natural selection should work to optimize flight performance. The similar size and flight speed of birds and bats may therefore suggest convergent aerodynamic performance; alternatively, flight performance could be restricted by phylogenetic constraints. We test which of these scenarios fit to two measures of aerodynamic flight efficiency in two passerine bird species and two New World leaf-nosed bat species. Using time-resolved particle image velocimetry measurements of the wake of the animals flying in a wind tunnel, we derived the span efficiency, a metric for the efficiency of generating lift, and the lift-to-drag ratio, a metric for mechanical energetic flight efficiency. We show that the birds significantly outperform the bats in both metrics, which we ascribe to variation in aerodynamic function of body and wing upstroke: Bird bodies generated relatively more lift than bat bodies, resulting in a more uniform spanwise lift distribution and higher span efficiency. A likely explanation would be that the bat ears and nose leaf, associated with echolocation, disturb the flow over the body. During the upstroke, the birds retract their wings to make them aerodynamically inactive, while the membranous bat wings generate thrust and negative lift. Despite the differences in performance, the wake morphology of both birds and bats resemble the optimal wake for their respective lift-to-drag ratio regimes. This suggests that evolution has optimized performance relative to the respective conditions of birds and bats, but that maximum performance is possibly limited by phylogenetic constraints. Although ecological differences between birds and bats are subjected to many conspiring variables, the different aerodynamic flight efficiency for the bird and bat species studied here may help explain why birds typically fly faster, migrate more frequently and migrate longer distances than bats

Refining transcriptional programs in kidney development by integration of deep RNA-sequencing and array-based spatial profiling

<p>Abstract</p> <p>Background</p> <p>The developing mouse kidney is currently the best-characterized model of organogenesis at a transcriptional level. Detailed spatial maps have been generated for gene expression profiling combined with systematic <it>in situ </it>screening. These studies, however, fall short of capturing the transcriptional complexity arising from each locus due to the limited scope of microarray-based technology, which is largely based on "gene-centric" models.</p> <p>Results</p> <p>To address this, the polyadenylated RNA and microRNA transcriptomes of the 15.5 dpc mouse kidney were profiled using strand-specific RNA-sequencing (RNA-Seq) to a depth sufficient to complement spatial maps from pre-existing microarray datasets. The transcriptional complexity of RNAs arising from mouse RefSeq loci was catalogued; including 3568 alternatively spliced transcripts and 532 uncharacterized alternate 3' UTRs. Antisense expressions for 60% of RefSeq genes was also detected including uncharacterized non-coding transcripts overlapping kidney progenitor markers, Six2 and Sall1, and were validated by section <it>in situ </it>hybridization. Analysis of genes known to be involved in kidney development, particularly during mesenchymal-to-epithelial transition, showed an enrichment of non-coding antisense transcripts extended along protein-coding RNAs.</p> <p>Conclusion</p> <p>The resulting resource further refines the transcriptomic cartography of kidney organogenesis by integrating deep RNA sequencing data with locus-based information from previously published expression atlases. The added resolution of RNA-Seq has provided the basis for a transition from classical gene-centric models of kidney development towards more accurate and detailed "transcript-centric" representations, which highlights the extent of transcriptional complexity of genes that direct complex development events.</p