Tropical origin

Primary irritant dermatitis caused by wood contact consists of erythema and blistering, which may be accompanied by erosions and secondary infections. Irritant chemicals typically are found in the bark or the sap of the outer part of the tree. Therefore, loggers and persons involved in initial wood processing are most affected. In most reports of contact dermatitis, hardwoods of tropical origin have been implicated, although other woods, including pine, spruce, western red cedar, elm, and alder, have been cited. 

In plants of tropical origin, the first intermediate into which 14C02 is fixed is oxaloacetate, a four-carbon compound. This reaction, which occurs in the cytosol of leaf mesophyll cells, is catalyzed by phosphoenolpyru-vate carboxylase, for which the substrate is HC03, not C02. The oxaloacetate thus formed is either reduced to malate at the expense of NADPH (as shown in Fig. 20-23b) or converted to aspartate by transamination ... 

MEDITERRANEAN BASIN, WIDESPREAD TROPICAL ORIGIN AND DISTRIBUTION... 

The linear dependence of the moduli on temperature results from the en-tropic origin of the elasticity. 

Production By steam distillation from seeds of Abel-moschus moschatus (Malvaceae), a hibiscus species growing in the tropics. Origin India, South America. Composition The main component is farnesyl acetate (50-60%) (C HjgOj, Mr 264.41), accompanied by some famesol (3-5%). TTie typical odor and taste determining component is ambrettolide. 

The Magnoliaceae is of tropical origin and is believed to be the ancestral host... 

Most oilseed residues are of tropical origin they include groundnut, cotton seed and soya bean. Some seeds such as castor bean yield residues are unsuitable for animal consumption because they contain toxic substances. 

However, to date reports on structural elucidations of resin glycosides are confined to 34 species belonging to six genera, altogether listed in Table 8.2 together with the respective authorities for the species and the phytochemical references Ipomoea (23 spp.), Merremia (3), Convolvulus (3), Operculina (2) Cuscuta (2), Calystegia (1). The vast majority of these plants are of tropical origin. 

VOC). Of most concern is the emission of terpenes. Terpenes are hydrocarbons present in conifer oleo-resins. They could also be found in many hardwoods, especially of tropic origin. Natural emissions take place everywhere in our forests and the quantity released naturally is much higher than the anthropogenic emissions. The problem with the latter is the very high local concentrations that can be achieved. Terpenes have a high reactivity in the atmosphere and may contribute to the formation of ground-level ozone. 

The all-inclusive character stroma can be employed for the definition of genera, subgeneric taxa, and sometimes only species, as, for example, in Pertusaria, where stromata are found in only some of the species and then usually just weakly delimited. It is remarkable that reproductive stromata are predominantly of tropical origin. The tendency to develop stromata may serve as a family-specific character in theTrypetheliaceae and Laureraceae. 

The observation that ALN and ALA were present, often at very high levels, in the xylem and phloem sap of plants provided support for the role of these ureides as translocatory compounds. Fosse (1926) demonstrated that ALN and ALA were present in the xylem sap of A. pseudoplatanus and P. vulgaris. Bollard (1957) noted in a more extensive survey that these ureides were present in the xylem fluid of 24 of the 103 species examined. Pate and associates have extended this study to include many members of the Leguminoseae (Pate and Atkins, 1983 Pate et al., 1980). Allantoin and ALA account for 50 to 99% of the organic nitrogen in the xylem stream of many legumes of tropical origin [e.g.. 

Allantoin and ALA, which are synthesized in the nodule, are the primary products of recent Nj fixation in legumes of tropical origin. These ureides are rapidly labeled after exposure of nodulated roots of soybean (Ohyama and Kumazawa, 1978 Schubert era/., 1981 Schubert and Coker, 1982) and cowpea (Herridge et al., 1978) to labeled N2. Allantoic acid accounted for 40% of the radioactivity after exposure of soybean nodules to Nj for 10 min (Schubert and Coker, 1982 Schubert et ai, 1981). Within 30-60 min of exposure of nodulated roots to Nj, labeled ureides were detected in the xylem sap of... 

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