Defence substances

Almost all types of signals, from sex pheromones to highly potent defence substances, are found among the isoprenoids. Many of these compounds seem to be directly sequestered from plants or represent simple transformation... 

There is little selectivity for the stereochemistry of the C02Et group but this fortunately did not matter in the synthesis of a natural defence substance from a sponge by G. A. Schiehser and J. D. White,... 

They are also an insect pheromone (grandisol) and defence substance (polyzonimlne), stephanine is an aporphine alkaloid, scytalone a fungal metabolite, and diosgenin is a rare vegetable saponin from Dioscorea, the Mexican yam. It is useful as animal steroids can be made from it (p. 999). 

They are also an insect pheromone (grandisol), a defence substance (polyzonimine), an important human metabolite (serotonin], a fungal metabolite (scytalone), and a toxic compound from hemlock (pelletierine). 

CisHjjO, Mr 218.34, oil, bp. 148-150°C (2.13 kPa). Alarm and defence substance of the ant species Lasius (Dendrolasius) fuliginosus K D. also occurs in the leaves of Torreya nucifera (Taxaceae) as well as in marine organisms. For synthesis, see Ut.. ... 

Gyrinidal. C,4)1,303, Mr 234.30. Defence substance of water beetles (Carabidae) of the genera Gyrinus and Dineutes produced in the so-called pygidial glands... 

CigHsgNj, Mr 282.51, yellowish oil, [a] -i-3.95° (ben-zeneX A defence substance of ladybird beetles (Coc-cinellidae) of the genus Harmonia occurring in the he-molymph of mature insects. On attack by a predator, H. is liberated by so-called reflex bleeding from the knee axilla. 

Occurrence Widely distributed in essential oils, especially of spice plants, fruit, vegetable, and meat flavor particularly important in the flavors of apple juice ( impact compound), kiwis, tea, and fresh tomatoes occurs also as an alaim or defence substance in various insects, e.g., bugs. For preparation, see Lit. used mainly in fruit and vegetable flavors. 

Insect defence substances see alarm substances, al-lelochemicals, semiochemicals, warning substances (odors), defensive secretions. 

Occurrence M. are widely distributed in the plant kingdom. They are obtained by steam distillation or by extraction from crushed plant parts (flowers, leaves, fruits, bark, roots) as essential (= volatile) oils. Since the M. are volatile the amounts of M. emitted by plants in tropical climate zones are considerable. In animal organisms, M. are present only in small amounts as pheromones or defence substances. 

Alkaloid from the marine ciliate Pseudokeronopsis rubra. Chemical defence substance. Black cryst. (MejCO). Mp 135-139 ... 

These unstable compounds were easily extracted from the intact mollusc and were separated by repeated reverse-phase liquid chromatography. The structures are based on spectroscopic data, particularly 360 MHz n.m.r. spectra, and some chemical transformations. Neither these compounds nor any likely precursors were present in the sponges which form the mollusc s diet, and it is suggested that the chloroacetylenes are chemical defence substances. 

Physiological Properties of Polyacetylenlc Compounds.- The role of polyacetylenes as phytoalexins (plant defence substances) has received considerable attention. The isolation of falcarinol,... 

Legume plants also contain many Hpophilic prenylated isoflavones (10-97), which are, in comparison with the original isoflavones, more efficient defence substances against pathogenic ilicitors (microorganisms) and animal pests (phytoalexins). They arise by prenylation of isoflavone precursors by dimethylallyl diphosphate. 

Onuma et al., 1999). The defence substances of fish have been reviewed several times (Bums, 1988 Maretic, 1988 Nair, 1988 Tachibana, 1988) more recent data on this type of compound are given by Abdul-Haqq and Shier (1991), Chhatwal and Dreyer (1992), Gwee et al. (1994), De Freitas and Malpezzi (1995), Malpezzi, De Freitas, and Rantin (1997), Church and Hodgson (2002), Geistdorfer and GoyfFon (2004) and Mebs (2006). 

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