Nutrient requirements Minerals

Nutritional Requirements. The nutrient requirements of mammalian cells are many, varied, and complex. In addition to typical metaboHc requirements such as sugars, amino acids (qv), vitamins (qv), and minerals, cells also need growth factors and other proteins. Some of the proteins are not consumed, but play a catalytic role in the cell growth process. Historically, fetal calf semm of 1—20 vol % of the medium has been used as a rich source of all these complex protein requirements. However, the composition of semm varies from lot to lot, introducing significant variabiUty in manufacture of products from the mammalian cells. 

Zinc is a required mineral nutrient in the diet of animals and the signs and effects of a dietary deficiency have been described in several species ( ). Nutritional zinc deficiency has also been described in humans (2). Signs of nutritional zinc deficiency may be manifest even though the individual is consuming an amount of dietary zinc that exceeds the usually designated requirement (2). Thus, bloavailabillty of dietary zinc is a factor that must be evaluated in considering adequacy of dietary intake (jl). 

ALTHOUGH ZINC WAS KNOWN as a required mineral nutrient for the diets of animals, zinc deficiency in humans diets was not recognized until the early 1960s. Individuals consuming an amount of dietary zinc exceeding the usual designated requirement still may show signs of nutritional zinc deficiency. Thus, the adequacy of zinc in humans diets must be evaluated based on the bioavailability of dietary zinc. 

Ingestad, T. (1979). Mineral nutrient requirements of Finns sylvestris and Picea abies seedlings. Physiologia Plantarum, 45, 373-80. 

The initial assumption might be that a photobiological H2 process would not require any raw materials. However, any biological process requires water and an adequate supply of macronutrients (i.e., nitrogen and phosphorus) and possibly some supplemental micronutrients, depending upon what nutrients and minerals are already present in the water supply to the process. One method to reduce raw material costs would be to utilize the waste stream from another process. For example, effluent streams from wastewater treatment anaerobic digesters are nitrogen rich, and blowdown streams from power plants are relatively pure. 

Taylor and Velbel point out that biomass storage may also decrease—i.e., the biomass does not always cause a net uptake of nutrients. If organic decay returns more nutrients to the soil solution than are taken up by plants, then a balance does not require mineral weathering, and nutrients are being lost to streams. Biomass decay can exceed biomass uptake when there is, e.g., insect defoliation of trees, storm losses of trees, timber cutting, or fire (Taylor and Velbel, 1991). 

The aerobic and anaerobic heterotrophic microbes present at vents often have complex nutrient requirements (e.g. organic acids, carbohydrates, elemental sulphur) some are believed to be mixotrophic, using both autotrophic and heterotrophic metabolisms (Karl, 1995 Kelley etal., 2002). Organic matter in sulphide mineral chimneys may come from other dead and/or pyrolysed microbes and invertebrates (e.g. worm tubes and muccus) during growth of chimneys. At most hydrothermal sites, thermal environments at moderate temperatures (50-90°C) are... 

What are required nutrients Required nutrients are substances that we must include in the diet and those that we keep track of. Sometimes this varies hy area. For example, in the United States, the only macronutrient we typically monitor is protein, as Americans get plenty of carbohydrates and fats. For micronutrients, we keep track of many vitamins and minerals, all of which are required for optimum health. 

Nonhuman primates have been used to test the cardiopathogenicity of vegetable oils. The diets that have been used in these experiments are listed in Table VI and VII. It should be recognized that the nutritional requirements of the various nonhuman primates have not been studied in detail. More research, particularly on mineral requirements and differences in nutrient requirements by the different species of monkeys, is necessary to overcome the general lack of information on the effect nutrition has on more subtle parameters of health (National Academy of Science, 1972). Nevertheless, from the examples of adequate diet given in the NAS requirements, it is apparent that most of the diets represented in Table VI and VII were nutri-... 

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