Alteration, indirect

Genotoxic modes of action involve genetic alterations caused by the substance interacting directly with DNA to result in a change in the primary sequence of DNA. A substance can also cause genetic alterations indirectly following interaction with other cellular processes (e.g., secondary to the induction of oxidative stress). 

Biological Corrosion The metabohc activity of microorganisms can either directly or indirectly cause deterioration of a metal by corrosion processes. Such activity can (1) produce a corrosive environment, (2) create electrolytic-concentration cells on the metal surface, (3) alter the resistance of surface films, (4) have an influence on the rate of anodic or cathodic reaction, and (5) alter the environment composition. 

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 extracellular calcium Ca -sensing receptor plays a central role in maintaining a nearly constant level of extracellular calcium by sensing small changes in Ca and directly and/or indirectly altering the translocation of calcium ions into or out of the extracellular fluid so as to normalize CaQ+. Changes in the level of expression and/or function of the CaR reset the level of CaQ+. Recently developed activators (calcimimetics)... 

Alterations to the P53 gene are the most common genetic defects known in cancer [5]. The protein product of P53 is involved in a number of pathways that directly and indirectly lead to apoptosis. Many genes that are involved in apoptosis can be induced by this protein, which is a transcriptional transactivator. The emerging hypothesis is that p53 is a central node of a complex apoptotic network that may function differ ently in diver se cell types and tissues. For example, Bax, the prototype proapoptotic member of the Bcl2 family, can be transcriptionally induced by p53 in certain, but not all, cell types. Like p53, Bax can modulate the extent to which cells are sensitive to apoptosis caused by therapeutic agents. 

Sensitive ecosystems that cannot neutralize the unnatural levels of acidity are adversely affected. Soil nutrient systems may be altered with a resulting direct or indirect damage to forest. Aquatic habitats have been chemically altered and many lakes and streams no longer support the traditional life forms. Fish have been lost from many lakes with a resulting affect on other food-web elements. 

Feedbacks may be affected directly by atmospheric CO2, as in the case of possible CO2 fertilization of terrestrial production, or indirectly through the effects of atmospheric CO2 on climate. Furthermore, feedbacks between the carbon cycle and other anthropogenically altered biogeochemical cycles (e.g., nitrogen, phosphorus, and sulfur) may affect atmospheric CO2. If the creation or alteration of feedbacks have strong effects on the magnitudes of carbon cycle fluxes, then projections, made without consideration of these feedbacks and their potential for changing carbon cycle processes, will produce incorrect estimates of future concentrations of atmospheric CO2. 

Since the binding of extraneous ions considerably alters the value of lEP of an aminoacid or protein, this point is not a constant. The term isoionic point (IP) is used to designate the pH value of a pure protein in salt-free water. The direct determination of this constant is difficult and because many proteins are insoluble in the absence of salts. The isoionic point is usually determined indirectly, that is, by measuring the lEP at different concentrations of the neutral salts and extrapolating to zero concentration The value of the isoionic point may differ from lEP by more than a pH unit (Haurowitz 1963). 

Three-spin effects arise when the nonequilibrium population of an enhanced spin itself acts to disturb the equilibrium of other spins nearby. For example, in a three-spin system, saturation of spin A alters the population of spin B from its equilibrium value by cross-relaxation with A. This change in turn disturbs the whole balance of relaxation at B, including its cross-relaxation with C, so that its population disturbance is ultimately transmitted also to C. This is the basic mechanism of indirect nOe, or the three-spin effect. 

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