Haemoglobins are iron-containing proteins that transport oxygen in the blood of most vertebrates. The mitochondrion is the cellular organelle which consumes oxygen in order to synthesise ATP. Mitochondrial dysfunction is implicated in neurodegeneration and ageing. We find that α and β haemoglobin (Hba and Hbb) proteins are altered in their distribution in mitochondrial fractions from degenerating brain. We demonstrate that both Hba and Hbb are co-localised with the mitochondrion in mammalian brain. The precise localisation of the Hbs is within the inner membrane space and associated with inner mitochondrial membrane. Relative mitochondrial to cytoplasmic ratios of Hba and Hbb show changing distributions of these proteins during the process of neurodegeneration in the pcd5j mouse brain. A significant difference in mitochondrial Hba and Hbb content in the mitochondrial fraction is seen at 31 days after birth, this corresponds to a stage when dynamic neuronal loss is measured to be greatest in the Purkinje Cell Degeneration mouse. We also report changes in mitochondrial Hba and Hbb levels in ageing brain and muscle. Significant differences in mitochondrial Hba and Hbb can be seen when comparing aged brain to muscle, suggesting tissue specific functions of these proteins in the mitochondrion. In muscle there are significant differences between Hba levels in old and young mitochondria. To understand whether the changes detected in mitochondrial Hbs are of clinical significance, we examined Parkinson's disease brain, immunohistochemistry studies suggest that cell bodies in the substantia nigra accumulate mitochondrial Hb. However, western blotting of mitochondrial fractions from PD and control brains indicates significantly less Hb in PD brain mitochondria. One explanation could be a specific loss of cells containing mitochondria loaded with Hb proteins. Our study opens the door to an examination of the role of Hb function, within the context of the mitochondrion—in health and disease.
It is a commonplace in the history of science that reputations of scientists play important roles in the stories of scientific knowledge. I argue that to fully understand these roles we should see reputations as produced by communicative acts, consider how reputations become known about, and study the factors influencing such processes. I reapply James Secord's ‘knowledge-in-transit’ approach; in addition to scientific knowledge, I also examine how ‘biographical knowledge’ of individuals is constructed through communications and shaped by communicative contexts. My case study is Carl Sagan, widely discussed – amongst scientists, media professionals and publics – for his skill as a charismatic popularizer, his perceived arrogance, his political activism, and his debated merit as a researcher. By examining how aspects of Sagan's reputation circulated alongside his scientific work – rather than existing as a static context for his scientific work – I show how different forms of knowledge (biographical and scientific) influence each other as they circulate.
This commentary considers the topics of humour and online settings. Both have received increasing attention amongst researchers and practitioners of science communication, and both raise numerous questions around the role of informality and enjoyment in the spread of information. However, online settings also provide a great range of data with which to address these questions. Here I suggest that close consideration of technical infrastructure plays an important role in this data collection. I shall do so using case studies drawn from two popular participatory websites, reddit and Facebook, which display contrasting attitudes towards using humour. I argue that these attitudes are partly products of the different tools provided by the pages for users to show appreciation, which affect the appearance of content on the websites. I also suggest that these tools allow users to appreciate jokes in multiple ways, and by extension might provide researchers with methods for assessing different forms of engagement. AbstractPublic engagement with science and technology; Science and media Keywords
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