Higher organization

Even higher organisms can be used for the production of labeled compounds. Plants, tobacco, or Canna indica for example, when grown in an exclusive atmosphere of radioactive carbon dioxide, [ 002], utilize the labeled precursor as the sole source of carbon for photosynthesis. After a suitable period of growth, almost every carbon atom in the plant is radioactive. Thus, plants can serve as an available source of C-labeled carbohydrates (9). 

A U.S. EPA study (41) showed that soil vapor extraction (SVE) is an effective treatment for removing volatile contaminants from the vadose zone. Sandy soils are more effectively treated than clay or soils with higher organic content because higher air flows are possible in sand and clays—organic soils tend to adsorb or retain more contaminants. Removal of volatiles is rapid in the initial phase of treatment and thereafter decreases rapidly thereafter-an important consideration in the design of air emissions control over the life of the project. 

Metals and metalloids that form alkyl compounds, eg, methylmercury and methylarsenic acid, tributjltin, deserve special concern because these compounds are volatile and accumulate in cells they are poisonous to the central nervous system of higher organisms. Because methylmercury or other metal alkyls may be produced at a rate faster than it is degraded by other organisms, it may accumulate in higher organisms such as fish. Hg species are also reduced to elementary Hg which is soluble in water but lost by volatilization to the atmosphere (40). 

Carbohydrates, polyhydric alcohols, higher organic acids (e.g. stearic), dibasic and hydroxy-acids cg. tartaric), certain amides (yg. oxamide), alkaloids, and azo and other organic colouis char... 

Dihydropteroic acid (85) is an intermediate to the formation of the folic acid necessary for intermediary metabolism in both bacteria and man. In bacteria this intermediate is produced by enzymatic condensation of the pteridine, 86, with para-amino-benzoic acid (87). It has been shown convincingly that sulfanilamide and its various derivatives act as a false substrate in place of the enzymatic reaction that is, the sulfonamide blocks the reaction by occupying the site intended for the benzoic acid. The lack of folic acid then results in the death of the microorganism. Mammals, on the other hand, cannot synthesize folic acid instead, this compound must be ingested preformed in the form of a vitamin. Inhibition of the reaction to form folic acid Ls thus without effect on these higher organisms. 

Higher organisms are not able to synthesize glucose from acetyl CoA but must instead use one of the three-carbon precursors lactate, glycerol, or alanine, all of which are readily converted into pyruvate. 

In higher organisms, calpain superfamily contains 16 independent genes that modulate cellular function. Out of them, 14 are Ca2+-dependent cysteine proteases. The other two encode smaller regulatory proteins that... 

Immunity is the innate or acquired ability of a higher organism to successfully defend life against potentially harmful agents like infections or poisons. 

Specific immunity is a highly sophisticated defense mechanism of higher organisms. A high level of... 

Higher organisms often elaborate several physically distinct versions of a given enzyme, each of which catalyzes the same reaction. Like the members of other protein families, these protein catalysts or isozymes arise through gene duplication. Isozymes may exhibit subtle differences in properties such as sensitivity to... 

In addition, the formation of terminal metabolites may be adverse either for the organism itself, or for other organisms in the ecosystem. Microbial metabolites may also undergo purely chemical reactions to compounds that are terminal products. Examples include the formation of 5-hydroxyquinoline-2-carboxylate from 5-aminonaphthalene-2-sulfonate (Nortemann et al. 1993) or benzo[fc]naphtho[l,2- /]thiophene from benzothiophene (Kropp et al. 1994). Microbial metabolites may be toxic to both the bacteria producing them and to higher organisms. Illustrative examples of toxicity include the following ... 

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