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Selenium is a component of the amino acids selenocysteine and selenomethionine. In humans, selenium is a trace element nutrient that functions as cofactor for glutathione peroxidases and certain forms of thioredoxin reductase. [1] Selenium-containing proteins are produced from inorganic selenium via the intermediacy of selenophosphate (PSeO 3 3 ...
Keshan disease. Keshan disease is a congestive cardiomyopathy caused by a combination of dietary deficiency of selenium and the presence of a mutated strain of Coxsackievirus, named after Keshan County of Heilongjiang province, Northeast China, where symptoms were first noted. These symptoms were later found prevalent in a wide belt extending ...
Selenium is toxic in high concentrations. As sodium selenite, the chronic toxic dose for human beings was described as about 2.4 to 3 milligrams of selenium per day. [7] In 2000, the US Institute of Medicine set the adult Tolerable upper intake levels (UL) for selenium from all sources - food, drinking water and dietary supplements - at 400 μg/day. [8]
Selenium deficiency occurs when an organism lacks the required levels of selenium, a critical nutrient in many species.Deficiency, although relatively rare in healthy well-nourished individuals, [1] can have significant negative results, [2] affecting the health of the heart and the nervous system; contributing to depression, anxiety, and dementia; and interfering with reproduction and gestation.
The selenium cycle is a biological cycle of selenium similar to the cycles of carbon, nitrogen, and sulfur. Within the cycle, there are organisms which reduce the most oxidized form of the element and different organisms complete the cycle by oxidizing the reduced element to the initial state. In the selenium cycle it has been found that ...
Nutrients in the soil are taken up by the plant through its roots, and in particular its root hairs.To be taken up by a plant, a nutrient element must be located near the root surface; however, the supply of nutrients in contact with the root is rapidly depleted within a distance of ca. 2 mm. [14] There are three basic mechanisms whereby nutrient ions dissolved in the soil solution are brought ...
In plants, it occurs as a bystander mineral, [107] sometimes in toxic proportions in forage (some plants may accumulate selenium as a defense against being eaten by animals, [108] but other plants, such as locoweed, require selenium, and their growth indicates the presence of selenium in soil). [109] The selenium content in the human body is ...
Hence, legumes are among the best sources of plant protein. When a legume plant dies in the field, for example following the harvest, all of its remaining nitrogen, incorporated into amino acids inside the remaining plant parts, is released back into the soil.