Fur in Magnetospirillum gryphiswaldense Influences Magnetosomes Formation and Directly Regulates the Genes Involved in Iron and Oxygen Metabolism

Magnetospirillum gryphiswaldense strain MSR-1 has the unique capability of taking up large amounts of iron and synthesizing magnetosomes (intracellular magnetic particles composed of Fe3O4). The unusual high iron content of MSR-1 makes it a useful model for studying biological mechanisms of iron uptake and homeostasis. The ferric uptake regulator (Fur) protein plays a key role in maintaining iron homeostasis in many bacteria. We identified and characterized a fur-homologous gene (MGR_1314) in MSR-1. MGR_1314 was able to complement a fur mutant of E. coli in iron-responsive manner in vivo. We constructed a fur mutant strain of MSR-1. In comparison to wild-type MSR-1, the mutant strain had lower magnetosome formation, and was more sensitive to hydrogen peroxide and streptonigrin, indicating higher intracellular free iron content. Quantitative real-time RT-PCR and chromatin immunoprecipitation analyses indicated that Fur protein directly regulates expression of several key genes involved in iron transport and oxygen metabolism, in addition it also functions in magnetosome formation in M. gryphiswaldense

Regulation of Petrobactin and Bacillibactin Biosynthesis in Bacillus anthracis under Iron and Oxygen Variation

siderophore biosynthetic operons that are responsible for synthesis of petrobactin and bacillibactin, during variable growth conditions., a member of the bacillibactin biosynthetic operon, was only transcribed under conditions of iron-depletion, regardless of growth aeration.

"You feel dirty a lot of the time" : policing 'dirty work', contamination and purification rituals

Following the controversial adoption of spit-hoods by some UK police forces, most recently by the London Metropolitan Police in February 2019, this article contributes to and extends debates on physical and symbolic contamination by drawing on established considerations of ‘dirty work’. The article argues that, for police officers, cleansing rituals are personal and subjective. As a relatively high-prestige occupation, police officers occupy a unique position in that they are protected by a status shield. Reflections from this ethnographic study suggest that the police uniform can be used as a vehicle for contamination and staff employ purification rituals and methods of taint management