Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Intra and inter-annual variation in the diet of Magellanic penguin (Spheniscus magellanicus) at Martillo Island, Beagle Channel

Knowledge of seabirds’ diet at each breeding site and its temporal variation is key to understanding and evaluating how changes in marine resources affect each seabird population. In this study, we determined the diet of Magellanic penguins (MP, Spheniscus magellanicus) at Martillo Island, accounting for sex, breeding stage and year. We analyzed a total of 144 stomach contents during three consecutive breeding seasons (2006–2007, 2007–2008 and 2008–2009) and stages (incubation, early and late chick-rearing). MP fed mainly on fuegian sprat (Sprattus fuegensis), which represented 75 % of the biomass consumed by birds during the entire study. The next important prey was squat lobster (Munida gregaria), followed by Patagonian squid (Loligo gahi). Both sexes consumed similar prey items. We observed variation in diet relative composition among breeding years and stages. Fuegian sprat consumption decreased throughout the years whereas squat lobster increased. Penguins consumed a higher proportion of squat lobster and Patagonian squid during the incubation stage than in the chick-rearing stages, whereas fuegian sprat was almost the only prey item consumed during the late chick-rearing stage. MPs show certain flexibility in the use of resources probably as a response to changes in prey populations. Variability in the diet among different reproductive stages could be related to changes in the distribution and abundance of their main prey near the colony during the breeding season together with changes in the energy requirements of seabirds.Fil: Scioscia, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Raya Rey, Andrea Nélida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Saenz Samaniego, Ricardo Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Florentin, Olga Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Schiavini, Adrian Carlos Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin