Team:Charlottesville RS/Project

Project Idea

Junk Food

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Project Realization

Nitrogen is essential for all living things: animals and plants. Nitrogen forms a part of the proteins and DNA that are found in cells. Animals get nitrogen by eating plants and other animals. Just like animals, plants require nitrogen to grow and survive. But they do not get nitrogen by consuming proteins like animals do. Plants get nitrogen from water and from the soil. They get nitrogen by absorbing it in the form of nitrates and ammonium. Nitrates are the major source of nitrogen for aquatic plants. Nitrates are not utilized by aquatic organisms such as fish and aquatic insects, but nitrates are used by aquatic plants.

Why nitrates are bad in drinking water High nitrate levels in water can cause methemoglobinemia or blue baby syndrome, a condition found especially in infants under six months. The stomach acid of an infant is not as strong as in older children and adults. This causes an increase in bacteria that can readily convert nitrate to nitrite (NO2). Do not let infants drink water that exceeds 10 mg/l NO3-N. This includes formula preparation. Nitrite is absorbed in the blood, and hemoglobin (the oxygen-carrying component of blood) is converted to methemoglobin. Methemoglobin does not carry oxygen efficiently. This results in a reduced oxygen supply to vital tissues such as the brain. Methemoglobin in infant blood cannot change back to hemoglobin, which normally occurs in adults. Severe methemoglobinemia can result in brain damage and death. Pregnant women, adults with reduced stomach acidity, and people deficient in the enzyme that changes methemoglobin back to normal hemoglobin are all susceptible to nitrite-induced methemoglobinemia. The most obvious symptom of methemoglobinemia is a bluish color of the skin, particularly around the eyes and mouth. Other symptoms include headache, dizziness, weakness or difficulty in breathing. Take babies with the above symptoms to the hospital emergency room immediately. If recognized in time, methemoglobinemia is treated easily with an injection of methylene blue. Healthy adults can consume fairly large amounts of nitrate with few known health effects. In fact, most of the nitrate we consume is from our diets, particularly from raw or cooked vegetables. This nitrate is readily absorbed and excreted in the urine. However, prolonged intake of high levels of nitrate are linked to gastric problems due to the formations of nitrosamines. N-nitrosamine compounds have been shown to cause cancer in test animals. Studies of people exposed to high levels of nitrate or nitrite have not provided convincing evidence of an increased risk of cancer.

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Project Perspectives

This project is supposed to be a wet model for a mechanism of specific target finding and elimination, in particular of cancer cells. There is clear evidence that bacteria accumulate in tumor areas [4, 5]. One reason might be the immunosuppressive effect of the tumor. The possibility to discriminate cancer patients from breath samples [6, 7, 8] gives rise to the idea to use bacterial receptors for the recognition of specific molecular exudation patterns. The effect of bacterial accumulation might in this way be enhanced by the engineering of a pattern sensitive chemotaxis mechanism. Furthermore bacteria could be induced very specifically in the near environment of the tumor to metabolize a pre-curser into a tumor suppressive molecule. Both mechanisms, increased accumulation at tumor sites and tumor located drug metabolism, would lead to a potentiated selectivity for the elimination of cancer cells. If the toxin is then also cancer cell specific - as could be shown by Pastan et al. [9] - then three strong effects would fulminate into ... of course, all this is still music of the future - but we are sure: it will be the future!

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