Oxygen energy metabolism

Atkinson, D.E. (1977). In Cellular Energy Metabolism and its Regulation. Academic Press, New York. Babcock, G.T. Wikstrom, M. (1992). Oxygen activation and the conservation of energy in cell respiration. Nature 356, 301-309. 

The reduction of the energy metabolism of normal lung tissue as indicated by decreasing oxygen-values, reflects reduced energy requirement due to reduced cellular synthesis during Rn/Rn-d exposure. 

As the power house of the cell, the mitochondrion is essential for energy metabolism. As the motor of cell death (1), this organelle is central to the initiation and regulation of apoptosis. In addition, mitochondria are critically involved in the modulation of intracellular calcium concentration and the mitochondrial respiratory chain is the major source of damaging reactive oxygen species. Mitochondria also play a crucial role in numerous catabolic and anabolic cellular pathways. 

Peripheral artery disease (PAD) patients usually feel leg pain when walking, which is caused by insufficient blood flow to keep up with energy demand. The P MRS data collected in a PAD patient group showed prolonged PCr recovery rate (or time constants) in the calf muscle after exhaustive exercise, suggesting the transition from anaerobic to aerobic energy metabolism is delayed due to impaired oxygen supply or mitochondria fimction caused by atherosclerosis. ... 

The role of oxygen in metabolism involves a paradox. Combustion of food to release and store its energy content requires a stepwise four-electron reduction of oxygen to produce harmless water, carbon dioxide, and ammonia (Figure 10.1). The first electron produces superoxide anion radical, the second produces peroxide anion, the third produces hydroxyl radical, and the fourth produces water. When this process is compartmentalized... 

Parasitic stages, on the other hand, generally do not use oxygen as the final electron acceptor but use fermentative processes to obtain most of their ATP. For these stages, an uneconomical energy metabolism is not detrimental, as the host provides the nutrients. Most adult flatworms inside the final host produce end products of a fermentative carbohydrate breakdown, such as succinate, acetate, propionate and lactate. These end products are formed via malate dismutation, a fermentative pathway, which is present in all types of parasitic worms (flatworms as well as many nematodes), but which is also present in animals like freshwater snails, mussels, oysters and other marine organisms. Malate dismutation is linked to a specially... 

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