Genomic capacities for Reactive Oxygen Species metabolism across marine phytoplankton.

Marine phytoplankton produce and scavenge Reactive Oxygen Species, to support cellular processes, while limiting damaging reactions. Some prokaryotic picophytoplankton have, however, lost all genes encoding scavenging of hydrogen peroxide. Such losses of metabolic function can only apply to Reactive Oxygen Species which potentially traverse the cell membrane outwards, before provoking damaging intracellular reactions. We hypothesized that cell radius influences which elements of Reactive Oxygen Species metabolism are partially or fully dispensable from a cell. We therefore investigated genomes and transcriptomes from diverse marine eukaryotic phytoplankton, ranging from 0.4 to 44 µm radius, to analyze the genomic allocations encoding enzymes metabolizing Reactive Oxygen Species. Superoxide has high reactivity, short lifetimes and limited membrane permeability. Genes encoding superoxide scavenging are ubiquitous across phytoplankton, but the fractional gene allocation decreased with increasing cell radius, consistent with a nearly fixed set of core genes for scavenging superoxide pools. Hydrogen peroxide has lower reactivity, longer intracellular and extracellular lifetimes and readily crosses cell membranes. Genomic allocations to both hydrogen peroxide production and scavenging decrease with increasing cell radius. Nitric Oxide has low reactivity, long intracellular and extracellular lifetimes and readily crosses cell membranes. Neither Nitric Oxide production nor scavenging genomic allocations changed with increasing cell radius. Many taxa, however, lack the genomic capacity for nitric oxide production or scavenging. The probability of presence of capacity to produce nitric oxide decreases with increasing cell size, and is influenced by flagella and colony formation. In contrast, the probability of presence of capacity to scavenge nitric oxide increases with increasing cell size, and is again influenced by flagella and colony formation.

Canadian Northern and Indigenous health policy responses to the first wave of COVID-19.

Aims: This study aimed to compare COVID-19 health policy and programme responses in 16 Northern and Indigenous regions in Canada. The goal was to summarise strategies used to mitigate the initial spread of the pandemic while highlighting aspects that reflect Indigenous values. Methods: A scoping review of grey literature was completed, focusing on territorial, regional health authority, and community level websites. Further media analysis was conducted to reach saturation regarding policy changes and programmes implemented to prevent transmission, improve health communication, access testing, provide health services effectively, secure borders, and provide financial assistance. Common responses were mapped on the Women's College Hospital's Wholistic Framework for Safe Wellness to identify aspects that reflected Indigenous values. This framework utilises the medicine wheel to discuss physical health (body), ceremony (spirit), community health (heart), and assessment (mind). Results: The Women's College Hospital's Wholistic Framework for Safe Wellness quadrants of the body, spirit and heart were covered by most regions via health communication efforts, adaptations to traditional practices, and continuation of care during the pandemic, respectively. It was found that 13 regions had pandemic responses adapted for Indigenous populations. Conclusions: The responses in each Northern region show that protecting each community was a priority; however, policies and programmes were developed as a kaleidoscope of what can be done quickly and evaluated later. Assessment, risk, and prevention, covered by the mind quadrant of the Women's College Hospital's Wholistic Framework for Safe Wellness, were missing in initial emergency responses. Increasing capacity for emergency management in Northern and Indigenous regions will require contingency planning that acknowledges and builds off traditional knowledge.