Terpenoids chemical changes

The example to be described, admittedly one whose chemistry is difficult, is, nonetheless, typical of the approach. In the case of Icacinaceae, Kaplan et al. (1991) studied the increase in complexity of terpenoid compounds of selected members of the family as a function of where, in the geographic range of the family, the various genera occur. Although the work was set in a taxonomic context—using chemical features to assess the proper placement of the family—our interest lies in the chemical changes that appear to be associated with geography. 

Balance volatile (terpenoids)/ nonvolatile. Chemical changes forT>149°C pH<4-Terpene,... 

Chang, M.C.Y., Eachus, R.A., Trieu, W. et al. (2007) Engineering Escherichia coli for production of functionalized terpenoids using plant P450s. Nature Chemical Biology, 3, 274—277. 

Py-FIMS results clearly reveal the existence of a thermally extractable, bitumen-like fraction which is chemically distinct from the remaining coal components. In lignite, several biomarker compounds were noticeable in the mobile phase components while bituminous coals contain various alkylsubstituted aromatic compounds in the mobile phase. Blind Canyon coal, which contains 11% resinite, exhibits mobile phase components believed to originate from terpenoid aromatization. Curie-point Py-LVMS results illustrate the importance of the oxidation status of coal for studying the mobile phase since mild air oxidation severely changes the structural characteristics of the thermally extractable mobile phase. 

Recent studies have described the complex, constitutive, and MeJA- and insect-induced terpenoid defenses in Norway spruce and Sitka spruce at anatomical, chemical, and biochemical levels. " Miller et al. compared the effect of MeJA treatment and white pine weevil attack on induced terpenoid defenses in Sitka spruce. They found that MeJA and real insects induce very similar terpenoid responses at the biochemical and molecular levels. The cloning and functional characterization of a family of ten, functionally diverse Norway spruce TPS genes not only allowed an improved phylogeny of the conifer TPS-d gene family but also allowed a detailed molecular and biochemical characterization of induced changes in terpenoid metabolite profiles in spruce defense. Many of the products of the recently identified Norway spruce TPS genes correspond with components of terpenoid metabolite profiles after MeJA treatment or insect attack in species of spruce. Our work on Norway spruce terpenoid responses to MeJA treatment " is discussed here with an emphasis on those compounds that are products of the newly characterized spruce TPS genes. ... 

As previously discussed (see Chapter 8), many plant secondary compounds are involved in plant-plant chemical warfare called allelopathy. Terpenoids often are involved in interactions of this nature (Fig. 19.20). Many monoterpenes inhibit germination of seeds and growth of seedlings. Exposure of plants to the monoterpene vapors produces developmental and physiological changes of several types (Fischer, 1986,... 

Plant-animal communication that occurs between the primary producers (plants), primary consumers (herbivorous animals) and secondary consumers (carnivorous animals) is one of the most intriguing and sensitive processes in ecosystems. In particular volatile terpenoids play an important role as chemical cues in these interactions below- and above ground and changes in the abiotic environment may disturb this interplay in different phases (Table 94.1, [24]). 

Once in the burial environment, biodeterioration may promote further alterations in the structure of the higher terpenoids. Whilst the particular chemical character of the burial environment will dictate specific changes, once again, alterations likely to be encountered will include oxidation, hydrogenation, etc. Looking then at the composition of freshly exuded and aged resins, whilst the more stable terpenoids may be present in both, the older material is likely to exhibit a higher proportion of oxidised terpenoids. 

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