Interacting nutrients

Kemp, W. M., and Boynton, W. R. (1992). Benthic-pelagic interactions Nutrients and oxygen dynamics. In Oxygen Dynamics in the Chesapeake Bay— A Synthesis of Recent Results (Smith, D. E., Leffler, M., and Mackieman, G., eds.). Maryland Sea Grant, CoUege Park, MD. pp. 149-209. 

This change is influenced by metaboHc hormone action rarely do any of the hormones or other influencing factors act independent of each other to regulate nutrient partitioning. Complex interactions aHow for integration of influences to accommodate a coordinated chronic regulation of nutrient use for maintenance or growth so that an animal may adapt to its environment (see Feeds AND FEED ADDITIVES). 

The nutrient sparing effect of antibiotics may result from reduction or elimination of bacteria competing for consumed and available nutrients. It is also recognized that certain bacteria synthesize vitamins (qv), amino acids (qv), or proteins that may be utilized by the host animal. Support of this mode of action is found in the observed nutritional interactions with subtherapeutic use of antibiotics in animal feeds. Protein concentration and digestibiHty, and amino acid composition of consumed proteins may all influence the magnitude of response to feeding antibiotics. Positive effects appear to be largest... 

Some elements found in body tissues have no apparent physiological role, but have not been shown to be toxic. Examples are mbidium, strontium, titanium, niobium, germanium, and lanthanum. Other elements are toxic when found in greater than trace amounts, and sometimes in trace amounts. These latter elements include arsenic, mercury, lead, cadmium, silver, zirconium, beryUium, and thallium. Numerous other elements are used in medicine in nonnutrient roles. These include lithium, bismuth, antimony, bromine, platinum, and gold (Eig. 1). The interactions of mineral nutrients with... 

In the first stages of the development of an Action plan all control options are considered. In the case of lakes, this process is aided by a PC-based expert system , PACGAP, which looks at the physical and chemical characteristics of the lake to determine the most likely option for control. Once further, more detailed information has been collected on the lake s nutrient inputs and other controlling factors, amore complex interactive model can be used (Phytoplankton Response To Environmental CHange, PROTECH-2) to define the efficacy of proposed control options more accurately. This model is able to predict the development of phytoplankton species populations under different nutrient and stratification regimes. 

The indirect pathway by which air pollutants interact with plants is through the root system. Deposition of air pollutants on soils and surface waters can cause alteration of the nutrient content of the soil in the vicinity of the plant. This change in soil condition can lead to indirect or secondary effects of air pollutants on vegetation and plants. 

The interactions in the intermediate-dose category may result in effects on the reproduction cycle of species, the utilization of nutrients, the production of biomass, and the susceptibility to disease,... 

Cells make use of many different types of membranes. All cells have a cytoplasmic membrane, or plasma membrane, that functions (in part) to separate the cytoplasm from the surroundings. In the early days of biochemistry, the plasma membrane was not accorded many functions other than this one of partition. We now know that the plasma membrane is also responsible for (1) the exclusion of certain toxic ions and molecules from the cell, (2) the accumulation of cell nutrients, and (3) energy transduction. It functions in (4) cell locomotion, (5) reproduction, (6) signal transduction processes, and (7) interactions with molecules or other cells in the vicinity. 

Fish from Lake Erie are generally the least contaminated of all the Great Lakes IS), It has been speculated that contaminants in a more advanced eutrophic system become masked or removed by sedimentation within the food chain and have less opportunity to reach higher trophic levels 24), The management implications of this interaction between nutrient and contaminants needs to be further elucidated. 

A TBma,) explicit functions of the available concentrations of the other nutrients. This approach allows for a pronounced interdependence between the fluxes of the different nutrients but it does not ensure that the Redfield ratios are maintained. In the second approach the contents of the nutrients in the biota reservoir are forced to remain close to the Redfield ratios. This method was used by Mackenzie et al. (1993) in their study of the global cycles of C, N, P, and S and their interactions. They were able to demonstrate how a human perturbation in one of these element cycles could influence the cycles of the other elements. 

Soillroot interactions. High external concentrations make the acquisition of water and nutrients difficult because of the low water potential of the soil solution, and of chemical competition between saline and nutrient ions. 

Approximately 15 per cent of osteoblasts become entrapped in their own matrix to become osteocytes. Osteocytes have a vast three-dimensional network of cell processes (canaliculi), providing nourishment and cell-cell interactions. Because they are located throughout bone tissue and have an extensive canalicular network, osteocytes are assumed to be a vital component of sensing mechanical signals. Nutrients are essential for the vitality of bone tissue and are obtained from the blood supply, limiting most osteocytes to lie within 150 p.m of a blood vessel, resulting in a high cellular density 25000 osteocytes within a square millimetre of bone... 

A number of factors described as influencing carotenoid bioavailability were regrouped under the SLAMENGFll mnemonic. Species of carotenoid. Linkages at molecular level. Amount of carotenoids consumed in a meal. Matrix in which the carotenoid is incorporated. Effectors of absorption and bioconversion. Nutrient status of the host. Genetic factors. Host-related factors, and Interactions among these variables. Only the factors that affect the micellarization of the compound in the gut are discussed and summarized in Table 3.2.1. 

Different factors inclnding nntrients, bile salts, pH, and microflora present in the gastrointestinal tract dnring the digestion process can affect the bioaccessibility of a compound (Table 3.2.1). The compoimd of interest is generally consiuned together with other nutrients present in the meal and, once the compound and these nutrients are released from the food matrix during the same period, they may interact in the intestinal liunen. 

Schlemmer U. Decker H. (1993) On the mechanism of the copper-pectin interaction. In proceedings of Bioavailability 93 Nutritional, Chemical and Food Processing Implications of Nutrient Availability. U. Schlemmer (Ed.). Ettlingen, May 9-12, 494-500. 

Plant survival and crop productivity are strictly dependent on the capability of plants to adapt to different environments. This adaptation is the result of the interaction among roots and biotic and abiotic components of soil. Processes at the basis of the root-soil interaction concern a very limited area surrounding the root tissue. In this particular environment, exchanges of energy, nutrients, and molecular signals take place, rendering the chemistry, biochemistry, and biology of this environment different from the bulk soil. 

Neutral interactions are found extensively in the rhizosphere of all crop plants. Saprophytic microorganisms are responsible for many vital soil processes, such as decomposition of organic residues in soil and associated soil nutrient mineralization/turnover processes. While these organisms do not appear to benefit or harm the plant directly (hence the tenn neutral), their presence is obviously vital for soil nutrient dynamics and their ab.sence would clearly influence plant health and productivity. 

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