The impact of fertilizer management on the oxidation status of terrestrial organic matter

The oxidative ratio (the ratio of moles of O2 produced per mole CO2 sequestered – OR) of the organic matter in the terrestrial biosphere governs the ability of the terrestrial biosphere to uptake CO2. The value of OR is known to vary between environments, but it would also be expected to vary with management. This study measured the OR of plant and soil samples from the long-term grassland plots on the Park Grass experiment at Rothamsted (SE England). The selected plots included those with different fertilizer inputs, including farmyard manure or inorganic fertilizers and an unfertilized control, each with and without lime. The measurements show that: (i) Use of inorganic fertilizer caused the OR of soil organic matter to increase. (ii) Farmyard manure (FYM) caused OR of the soil to increase but that of the vegetation decreased. (iii) Liming had the effect of decreasing OR and counteracting effects of fertilizer. (iv) The OR of the ecosystem increased with FYM application but decreased with inorganic fertilizer application. The global pattern in the use of organic amendments and inorganic fertilizers suggests that the likely impact of the predicted increase in global inorganic fertilizer use will result in a net decrease in the OR of the organic matter of the terrestrial biosphere, and an increase in its ability to act as a carbon sink. Corresponding increases in global FYM use and its impact upon global OR are unlikely to be large enough to counteract this effect

The "selfish brain" hypothesis for metabolic abnormalities in bipolar disorder and schizophrenia A hipótese do "cérebro egoísta" para alterações metabólicas no transtorno bipolar e na esquizofrenia

Metabolic abnormalities are frequent in patients with schizophrenia and bipolar disorder (BD), leading to a high prevalence of diabetes and metabolic syndrome in this population. Moreover, mortality rates among patients are higher than in the general population, especially due to cardiovascular diseases. Several neurobiological systems involved in energy metabolism have been shown to be altered in both illnesses; however, the cause of metabolic abnormalities and how they relate to schizophrenia and BD pathophysiology are still largely unknown. The "selfish brain" theory is a recent paradigm postulating that, in order to maintain its own energy supply stable, the brain modulates energy metabolism in the periphery by regulation of both allocation and intake of nutrients. We hypothesize that the metabolic alterations observed in these disorders are a result of an inefficient regulation of the brain energy supply and its compensatory mechanisms. The selfish brain theory can also expand our understanding of stress adaptation and neuroprogression in schizophrenia and BD, and, overall, can have important clinical implications for both illnesses.<br>Alterações metabólicas são frequentes em pacientes com esquizofrenia e transtorno bipolar (TB), levando a uma alta prevalência de diabetes e síndrome metabólica nessa população. Além disso, as taxas de mortalidade entre pacientes são mais altas do que na população geral, especialmente em decorrência de doenças cardiovasculares. Vários sistemas neurobiológicos envolvidos no metabolismo energético têm demonstrado alterações nas duas doenças; no entanto, a causa das alterações metabólicas e a forma como elas se relacionam com a fisiopatologia da esquizofrenia e do TB ainda são arenas em grande parte desconhecidas. A teoria do "cérebro egoísta" é um paradigma recente que postula que, para manter estável seu próprio fornecimento de energia, o cérebro modula o metabolismo da energia na periferia regulando tanto a alocação quanto a ingestão de nutrientes. Apresentamos neste artigo a hipótese de que as alterações metabólicas observadas nesses transtornos são resultado de uma regulação ineficiente do fornecimento de energia do cérebro e seus mecanismos compensatórios. A teoria do cérebro egoísta também pode expandir nosso entendimento sobre a adaptação ao estresse e a neuroprogressão na esquizofrenia e no TB, e, acima de tudo, pode ter implicações clínicas importantes para as duas doenças