Trace nutrients

The Sugars Task Force s Select Committee on Nutrition and Human Needs recommended a daily consumption of sugars at 10% of total calories, which approximates current (11%) daily intake levels in the United States. At this level, sucrose does contribute to the development of dental caries however, no firm evidence exists that it causes dietary imbalances or deficiencies of vitamins (qv), minerals, or trace nutrients (62). 

Grape and apple juices usually contain all of the trace nutrients required by Saccharomjces for fermentation of sugars to alcohol. Other fmit and diluted honey, as well as barley malt and rice extract, frequendy need additions of nitrogen, phosphoms, and potassium compounds, together with some autolyzed yeast to faciUtate the yeast growth necessary for fermentation. Stimulation oiy4.cetobacter frequendy requires the addition of autolyzed... 

Approximately 5% of the U.S. consumption of is in agriculture. Boron is a necessary trace nutrient for plants and is added in small quantities to a number of fertilizers. Borates are also used in crop sprays for fast rehef of boron deficiency. Borates, when apphed at relatively high concentration, act as nonselective herbicides. Small quantities of borates are used in the manufacture of alloys and refractories (qv). Molten borates readily dissolve other metal oxides usage as a flux in metallurgy is an important apphcation. Other important small volume apphcations for borates are in fire retardants for both plastics and ceUulosic materials, in hydrocarbon fuels for fungus control, and in automotive antifreeze for corrosion control (see Corrosion and corrosion inhibitors). Borates are used as neutron absorbers in nuclear reactors. Several borates, which are registered with the Environmental Protection Agency (EPA) can be used for insecticidal purposes, eg, TIM-BOR. 

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). 

Nutrients can be classified into three groups based on levels required in waste treatment systems. These are given in Table 9. The major nutrients can be identified from the generalized biomass formula (Ceo Hg2 O23 Ni2 P). The actual quantity needed depends on the biochemical oxygen demand (BOD) of the waste. The higher the BOD the greater the quantity of cells produced. The minor and trace nutrients are needed in small quantities and are given in terms of concentration because these are the levels needed in solution to force the small amount required inside the cell across the cell-wall membrane. 

For many of the trace nutrients, it will be difficult to find literature references to the concentrations required. It is only recently that it has been realized that these trace nutrients are required, because they were only present as contaminants in biological preparations. Indeed, many other substances may be required nutrients but at such low levels that their requirement is not easily manifest. 

The toxicity of selenium (Se) belies the fact that it is a required trace-nutrient for many biological organisms. The general order of toxicity for the most... 

Table 1. The lower, optimum and upper limit concentrations of essential trace nutrients in soils of North Eurasia.

Trace nutrient Number of samples Deficit/lower Optimum Excess/upper... 

Trace nutrient Number of samples Mean content in pasture crops Lower (deficit) Optimum for animal organisms Upper (excess)... 

We can see from Figure 3 that the moderate deficit of I, Co, Zn, Cu, Mo, B, and Mn with optimal ratios of trace metals to I and Si, is characteristic for all links of a biogeochemical food web. These biogeochemical peculiarities favor the optimal physiological regulation of exchange processes in animal and human organisms. However, a moderate deficit of essential trace nutrients weakens the human immune... 

Thus, the community effect can have a positive impact on the biouptake of certain trace nutrients. 

Although dairy interests continue to advertise milk as the perfect1 or bear perfect food, the fact remains that cows milk is not a very good source of B vitamins in terms of percent composition by weight. After all, milk solids constitute only 12-13% of fluid milk and that means a rather large intake ratio of water to solids (about 7/1)> not exactly ideal for obtaining trace nutrients such as the B vitamins. 

Mo biological uptake and processing. As an essential trace nutrient. Mo uptake and incorporation into enzymes is tightly controlled at the cellular level via selective pumps and... 

This lack of development in aquatic allelochemistry appears an anachronism. It is not. Specifically reflecting the pervasive and peculiar effects of water, analysis of allelochemical events in aquatic systems has presented unique problems. Among the most significant are (a) the widespread and unpredictable occurrence of secondary activity, and (b) the difficulties of distinguishing between ultra-trace nutrient requirements and allelochemical effects. Both generate a need for unusually rigid experimental control. 

Borax decahydrate occurs in nature as mineral, borax (tincal). It is one of the most common sodium borate ores. The compound has several industrial applications. The refined material is mostly used in household cleaning products. It is used to make pyrex and other horosilicate glasses. Borax is added to fertilizers in small quantities as a source of boron, as a trace nutrient for plants. High purity grade borax is used in cosmetics, toilet products and electrolytic capacitors. It also is used in fire retardants, adhesives and herbicides. 

Agriculture therefore depends on there being a sufficient supply of inorganic nutrients to plants. Cereals, vegetables, fruit-bearing trees or plants, and animal fodder require bioavailable nutrients, that is, nutrients in forms that they can use. Since intensive agriculture depletes many natural nutrients, synthetic nutrients (fertilizers) must be supplied.1-7 In particular, we need to fix the inert N2 of the atmosphere as soluble, reactive compounds such as nitrates, ammonia, and ammonium salts. Other major fertilizer components are sulfate, potassium, and phosphate ions. It may also be necessary to provide trace nutrients, such as cobalt compounds, or to remove excess soil acidity by treatment with lime (CaO). World fertilizer demand in the year 2001 is expected to be about 1.5 x 10s metric tons N, 7.6 x 107 metric tons P2O5, and 6.7 x 107 metric tons K2O these projections represent an... 

Several elements, particularly zinc and copper, could play a role as trace nutrients for phytoplankton. They are known to be important for growth of terrestrial plants, but neither the requirement for these nutrients nor the elemental distributions in seawater are well known. The biological availability of both zinc and copper is controlled by their complexation with organic material. Analytical methods that have the distinction of being able to discriminate chemical forms of the metal are needed. These measurements reflect the chemical reactivity and biological availability or toxicity of the metal more accurately. 

The short-term, in situ bioavailability of organic matter is a complex function of intrinsic factors, such as the chemical characteristics of the DOM itself, which include of molecular weight distribution, the nutrient contents, and the relative contribution of broad classes of compounds and are determined by the source and the diagenetic state of the matter (Amon et al., 2001). The utilization of DOM and its apparent lability are also affected by extrinsic factors regulating the metabolism of bacteria and, therefore, the utilization of the organic matter by the bacterial community. These factors include temperature, the availability of inorganic and trace nutrients, trophic interactions within microbial food webs, and even the... 

Vanadium has marked influences on cellular growth, cellular oxidation-reduction, and enzyme function. The metal is part of the active site of some enzymes, widely believed to be a required ultra trace nutrient, and is toxic in large amounts. The development of vanadium complexes as therapeutic agents for diabetes and cancer is being actively pursued. Much of the influence of vanadium on biological processes... 

---