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Using Metagenomics to Monitor Microbial Communities

Executive summary:
The Advanced Microbial Solutions Company is exploring a new approach to isolate novel organisms or gene from the environment for commercial exploitation. This approach is enabled by metagenomics, a high throughput capacity that can deal with the DNA extraction, sequencing and interpretation of microbial communities. The R

Metabolic and Biochemical Effects of Food and Exercise

Although moderate exercise can benefit health, acute and rigorous exercise regime can be sometimes hazardous to health. Regular exercise will reduce the risk of chronic diseases such as cancer, diabetes, cardiovascular diseases. However the amount of exercise required to achieve beneficial effects has not been clearly defined but to gain maximum health benefits, the frequency, intensity and the duration of exercise and pre-exercise fitness levels will be important determents. (McCutcheon et al, 1991)
Strenuous exercise can induce alterations in the physiology and viability of circulating leucocytes which cause induced immune distress. Cumulating evidence has shown that intense exercise has adverse effects on adverse aspects of health. Rigorous physical activity can trigger an acute myocardial infarction and increase the occurrence of premature ventricular depolarisations which has been associated with long-term increase in the risk of cardiovascular deaths. Number of apoptosis of lymphocytes has been shown to be induced by intense treadmill exercise and this also induces cellular and oxidative stress. Study shows that Leucocyte mitochondrial transmembrane potential (MTP), a marker of the energy and redox status of the cells declined significantly after exhaustive aerobic exercise having a temporal relationship with intravascular oxidative stress. The changes in leucocyte MTP had declined significantly after the 1st exercise and it decreased even more after the 2nd and 3rd exercise sessions. The propensity of apoptosis of PMN, lymphocytes and monocytes increased gradually after each exercise session. (Kong, 2008)
In comparison with regular and intense exercise, several evidences showed the potential risks of acute and high intensity exercise. Exercise can elicit changes in the cellular and humoral immune systems and strenuous exercise can induce inflammatory reactions and immune disturbances. In addition to the immune disturbances, the energy needed for the increased metabolic demand during prolonged exercise is produced by oxidative metabolism, which may overwhelm endogenous antioxidative capacity and cause damage to cells and tissues. An example of exercise induced oxidative damage is DNA damage of leucocytes induced by high intensity aerobic exercise. (Kong, 2008) According to studies, strenuous exercise can induce the formation of reactive oxygen species, causing oxidative stress in areas where tissues are affected. The accentuated production of the reactive oxygen species may induce increased expression of death receptors and ligands and also disruption of leucocyte MTP. The variable correlation between the change of leucocyte MTP and apoptotic regulators implies that the leucocyte mitochondrial alterations are part of systematic immune disturbance induced by both short- term and high intensity exercise. The increased inflammatory cytokines and apoptotic regulators noticed after exhaustive physical activity will have deleterious effects on peripheral blood leucocytes. (Kong, 2008)
During intense exercise regimes for short durations, it has been shown that the body’s preferred energy substrate is glycogen. Glycogen is essentially a stored form of glucose in the liver and the skeletal muscle. During high intensity exercise regime, there is a reduction in the glycogen from 90mmol- kg-1 to 40 mmol-kg-1.This 50% reduction in glycogen may decrease the rate of glycolysis and this can bring in earlier onset of fatigue. (McCutcheon et al, 1991)
What is more not only glycogen level has been changed during exercise. Carbohydrate and fatty acid can be also use as a fuel. However, it depends on exercise intensity. George Brooks in ‘crossover concept’ explains this correlation. Input of carbohydrate oxidation to ATP formation rises while lipid oxidation decreases. Carbohydrate seems to be better source of energy for exercising muscles because it can creates greater rate of acetyl CoA for Krebs cycle. Moreover, carbohydrate can be also use in anaerobic glycolysis. (Houston, 2001)
High intensity exercise lead to several immune marker changes such as low level salivary immunoglobulin (antibodies), low serum complement levels, low lymphocyte count, depressed NK cell activity and decreased neutrophil phagocytic capacity. (Mackinnon 1992; Nieman; 1994; Pedersen