Interfering nutrients

Humans can absorb up to 50% of dietary copper in the gastrointestinal tract, depending on the presence of other interfering nutrients. Organic complexes facilitate the transport of Cu through the cell walls. Ab-... 

Eor example, beryUium occurs at the bottom of a displacement series with NTA allowing this metal to be recovered as the hydroxide by pH adjustment of an ore processing solution all of the interfering metals remain sequestered by chelation (14). Additionally, because other metals present caimot displace iron in an iron—EHPG chelate, the chelate can be used in highly calcareous soils to supply iron as a trace nutrient in agriculture (15). 

Certain weeds are a serious problem throughout the tropics. They compete for water, space, and nutrients and have actually made some large areas virtually unusable. In addition, some of them actually penetrate into the roots and tubers of crop plants, thus making wounds through which microorganisms enter as well as interfering with a normal growth (3, 47, 52). 

Boron may be an essential nutrient in several species of aquatic vertebrates. Insufficient boron (<3 pg B/L 62 pg B/kg ration) interfered with the normal development of the South Afiican clawed frog (Xenopus laevis) during organogenesis, and substantially impaired normal reproductive function in adult frogs (Fort et al. 1998). Impaired growth of rainbow trout (Oncorhynchus mykiss) embryos was documented at <90 pg B/L, and death of zehrafish (Brachydanio rerio) embryos at <2 pg B/L (Rowe et al. 1998). 

As another point of attack, cancerous cells have high metabolic rates, which means they rely heavily on biochemical nutrients, such as the dihydrofolic acid shown in Figure 14.17. The anticancer agent methotrexate is structurally very similar to dihydrofolic acid and works by binding to dihydrofolic acid receptor sites in the cancerous cells, thereby interfering with metabolic reactions in the cells. 

Antioxidant-rich phytochemicals are micro-constituents in plants and agricultural food products. They differ from proteins, carbohydrates, and lipids, which are macro-nutrients that are abundant in plants and food products. The type and quantity of antioxidant-rich phytochemicals vary significantly from source to source. Different types of the antioxidant-rich phytochemicals may have different antioxidant and other biological activities and bio availability. Although most phytochemicals have UV absorption, using traditional spectrophotometeric methods to quantify the antioxidants is not practical as they could be significantly masked or interfered with by many other compounds in the sources. Thus, the analysis methods for antioxidant-rich phytochemicals are more complicated and sophisticated than the methods used for macro-nutrient compounds. 

Molybdenum (Mo) is an essential plant nutrient. It acts as a metallic cofactor in plant and animal enzymes. At high concentrations in forages, it can be toxic to ruminants by interfering with assimilation of copper (Cu). The range between toxicity and deficiency in animals is narrow, and therefore careful control of Mo in animal diets is essential. 

The herbicidal mode of action of benzoxazinoids is unknown. Sanchez-Moreiras et al. [127] reviewed what was known of the mode of action of BOA up until about 2003. BOA can inhibit mitochondrial function by interfering with both electron transport and mitochondrial ATPase activity [128]. A correlation between inhibition of plasma membrane H " -ATPase activity and inhibition of growth by BOA and DIBOA [129], suggests that their effects on nutrient uptake and electrolyte leakage could be caused by this primary effect [130]. BOA reduces the number of dividing meristematic... 

The presence of parasites in a host s tissues, blood-cells, bloodstream or liver must to some extent disturb his metabolism. But at present we have no evidence that it does so in a manner that can fairly be described as interfering with ins nutrition. Parasites so situated may cause specific disease, but this can hardly be called nutritional the possible diversion of nutrients from normal metabolic channels in the host s efforts to deal with his parasites is discussed in the next section. 

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