Precursor plants

Boteha-Pavia, P. et al.. Regulation of carotenoid biosynthesis in plants evidence for a key role of hydroxymethylbutenyl diphosphate reductase in controhing the supply of plastidial isoprenoid precursors. Plant J. 40, 188, 2004. 

Erlander, S. R. (1998b). Starch biosynthesis. II. The statistical model for amylopectin and its precursor plant glycogen. Starch/Stdrke. 50, 275-285. 

Sulfur isotopic measurements can shed light on the origin of sulfur in coal. The 34S/32S ratio depends on the source of sulfur and the geologic processes involved during coal formation. For example, isotopic compositions are different for the two principal sources of sulfur in coal 1) the sulfur preserved from the precursor plant material, and 2) the sulfur derived from the bacterial reduction of dissolved sulfate in ambient waters. Plant assimilation of sulfur results in a slight depletion of 34S (4-4.5%c) relative to the 834S in the dissolved sulfate source (102.103). In contrast, the dissimilatory bacterial reduction of sulfate results in a large isotopic fractionation sulfide sulfur can be depleted as much as 60%o in the heavy isotope (89.104-106). 

Goupil, P., Croisille, Y., Croisille, F., and Ledoigt, G., Jerusalem artichoke invertases immunocharacterization of a soluble form and its putative precursor, Plant Sci., 54, 45-54, 1988. 

Elge, S., Brearley, C., Xia, H.J., Kehr, J., Xue, H.W., and Mueller-Roeber, B., 2001, An Arabidopsis inositol phospholipid kinase strongly expressed in procambial cells Synthesis of Ptdlns(4,5) P2 and Ptdlns(3,4,5)P3 in insect cells by 5-phosphorylation of precursors. Plant J. 26 561-571. 

Precursor Plants Rare events in populations generally cannot be detected unless 1,000 or more individuals are analyzed from each location. However, we proceeded in a slightly different manner. Seedlings of C. album were collected in areas that have never been treated with cEemicals. When transplanted in a greenhouse, one leaf per plant was cut off and left to absorb atrazine in the dark and then the amounts of chlorophyll fluorescence were recorded. 

TABLE II OCCURRENCE OF MUTANT PRECURSOR PLANTS IN POPULATIONS... 

Harley SM and Lord JM (1985). In vitro endopro-teolytic cleavage of castor bean lectin precursors. Plant Sci, 41, 111-116. 

M.-A. Pierrel, R. Atanassova, D. Werck-Reichhart, B. Fritig, and P. Saindrenan Free and conjugated benzoic acid in tobacco plants and cell cultures. Induced accumulation upon elicitation of defense responses and role as salicylic acid precursors Plant Physiol. 125 (2001) 318-328. Search for other oxygenases provides similar references. 

The principle of SNIF-NMR is based on the fact that the natural biosynthesis of any organic compound generates a unique isotope distribution at different tire molecular positions for that compound. These isotopic fingerprints are determined by the nature of the precursors, the chemical or biochemical synthesis mechanisms, the evolution of the environmental conditions, and even the physiological status of the precursor plant. Synthetic benzaldehyde lias an almost perfectly random distribution of deuterium on the benzene ring, and... 

The ash of many coals have long been known to contain beryllium in concentrations as much as 100 ppm. Since beryllium is mainly in the organic matter of the coal, it is indicative that it was a constituent of the precursor plants. 

Carotene is found in plant chioroplasts. When ingested into animals it serves as a precursor of vitamin A (the transformation occurs in the liver). 

M.p. 140°C. An amino-acid occasionally formed in the hydrolysis products of proteins and occurring in the urine of some birds as dibenzoylornithine. Ornithine is a precursor of arginine in plants, animals and bacteria. 

In plants phenol biosynthesis proceeds by building the aromatic ring from carbohydrate precursors that already contain the required hydroxyl group... 

Phenol biosynthesis in plants proceeds from carbohydrate precursors whereas the pathway in animals involves oxidation of aromatic rings... 

Aminocyclopropanecarboxylic acid an a ammo acid that is the biological precursor to ethylene in plants... 

The pentosan polysaccharides, xylan and arabinan, commonly known as hemiceUulose, are the principal precursors of furfural and are always found together with lignin and cellulose in plant materials. 

Air pollution can be considered to have three components sources, transport and transformations in the atmosphere, and receptors. The source emits airborne substances that, when released, are transported through the atmosphere. Some of the substances interact with sunlight or chemical species in the atmosphere and are transformed. Pollutants that are emitted directiy to the atmosphere are called primary pollutants pollutants that are formed in the atmosphere as a result of transformations are called secondary pollutants. The reactants that undergo transformation are referred to as precursors. An example of a secondary pollutant is O, and its precursors are NMHC and nitrogen oxides, NO, a combination of nitric oxide [10102-43-9] NO, and NO2. The receptor is the person, animal, plant, material, or ecosystem affected by the emissions. 

The second experimental problem is that incorporation of a material such as loganin (34), or even an amino acid which seems cleady to be a precursor by some biogenetic hypothesis, does not necessarily prove it is a precursor. The material fed may so completely swamp the normal pathways in the plant that the utiliza tion of what was fed generates an aberrant path which nonetheless produces the same product. 

Miscellaneous Alkaloids. Stukimic acid (57) is a precursor of anthranihc acid (28) and, in yeasts and Escherichia coli (a bacterium), anthranHic acid (o-aminobenzoic acid) is known to serve as a precursor of tryptophan (26). A similar but yet unknown path is presumed to operate in higher plants. Nonetheless, anthranHic acid itself is recognized as a precursor to a number of alkaloids. Thus damascenine [483-64-7] (134), C qH NO, from the seed coats of JSHgella damascena has been shown (95) to incorporate labeled anthranHic acid when unripe seeds of the plant are incubated with labeled precursor. 

Dehydrogenation. Dehydrogenation of / -butane was once used to make 1,3-butadiene, a precursor for synthetic mbber. There are currently no on-purpose butadiene plants operating in the United States butadiene is usually obtained as a by-product from catalytic cracking units. 

---