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

Efeito do CO2 e etileno no período de dormência de minitubérculos de batata cv. Macaca Effect of CO2 and ethylene on the dormancy period of potato cv. Macaca minitubers

Avaliou-se o efeito do CO2 e etileno no período de dormência de minitubérculos de batata da cultivar Macaca produzidos em telado durante duas safras. Imediatamente após a colheita, os minitubérculos foram submetidos aos tratamentos de abafamento com etileno (1000 mL L-1) por 72 h; CO2 (20%) por 72 h; carbureto de cálcio (200 g m-3) por 72 h; e 1-metilciclopropeno (1-MCP) (1mL L-1) por 24 h (apenas na safrinha); e imersão em solução de ethephon (840 mg L-1) por 5 s. A testemunha não recebeu nenhum tratamento. O delineamento experimental foi um fatorial (safras x tratamentos) no inteiramente casualizado, com quatro repetições de 15 minitubérculos. Em intervalos semanais foram avaliadas a respiração e a produção de etileno. A cada 15 dias avaliou-se o número de brotos e a percentagem de tubérculos brotados, calculando-se a área abaixo da curva de progressão. Os minitubérculos produzidos durante a safra, comparados com os da safrinha, apresentaram menor período de dormência e aumentaram a taxa respiratória durante o período de armazenamento, claramente relacionados com a brotação dos minitubérculos. O CO2 e etileno não promoveram o encurtamento, enquanto que o 1-MCP prolongou o período de dormência de minitubérculos de batata cv. Macaca.<br>The effect of CO2 and ethylene treatments were evaluated on the dormancy period of 'Macaca' minitubers produced in greenhouse during two growing seasons. Minitubers were treated soon after harvesting. The treatments were suffocation with ethylene (1000 mL L-1) during 72 h; CO2 (20 %) during 72 h; calcium carburet (200 g m-3) during 72 h; and 1-methylcyclopropene (1-MCP) (1 mL L-1) during 24 h (only for second season); and immersion with 2-cloroetil fosfonic acid (840 mg L-1) during 5 s. Control minitubers did not receive any treatment. The experiment was a factorial (seasons x treatments) in a randomized design, with four replications of 15 minitubers. Respiration and ethylene production were evaluated every week. Sprout number and percentage of sprouted tubers were evaluated every 15 days to obtain the area under progression curve. Minitubers produced during the first season presented shorter dormancy than those produced during the second season. First season minitubers presented an increase in respiration rate during storage that was clearly related to sprouting. CO2 and ethylene did not reduce, while 1-MCP enhanced dormancy period of potato cv. Macaca minitubers