Type II pheromones

Polyunsaturated hydrocarbons and the epoxy derivatives with a longer straight chain (C17-C23) comprise a second major group [9], the Type II pheromones (A in Fig. 1). They lack a functional group at the terminal position,... 

Fig. 10A-D Diagnostic fragment ions for the GC-MS analysis of Type II pheromones A Z6,29-dienes and Z3,Z6,Z9-trienes B monoepoxy derivatives of Z3,Z6-dienes C monoepoxy derivatives of Z3,Z6,Z9-trienes D diepoxy derivatives of Z3,Z6,Z9-trienes...

LC is also useful for the preparation of Type II pheromones. Monoepoxy compounds in this class have been systematically synthesized by the oxidation... 

Fig. 12A-C Separation of Type II pheromone components by HPLC with an ODS column (4.6 mm ID X 25 cm) A a crude pheromone extract of Spilosoma imparilis (Arctiidae, 2 FE) including l,Z3,Z6,epo9-21 H (I),Z3,Z6,epo9-21 H (II),Z3,Z6,epo9-23 H (III),Z6,epo9-23 H (IV), and Z3,Z6,Z9-21 H (V) detected by UV 215 nm B a mixture of synthetic standards (ca. 1 pg each of II-V) detected by RID C the same synthetic mixture detected by UV 215 nm. The solvent system is 3.5% water in MeOH (1.0 ml/min)...

Currently, LC-MS is widely used for the analysis of polar compounds, such as medicinal metabolites and bioactive peptides, since the interface has been improved and several new ionization methods have been developed. The sensitivity and reproducibility are sufficient for a daily quantitative analysis. The usefulness of the LC-MS has been demonstrated for studies on Type II pheromones using a time-of-flight MS with electrospray ionization (ESI) [180]. Each epoxydiene derived from the (Z3,Z6,Z9)-triene shows three ion series of [M+NHJ+, [M+H]+, and [M-OH]+ with high resolution and good sensitivity, indicating its molecular formula. In addition to these, characteristic fragment... 

Biosynthesis of triene pheromone components with a triene double bond system that is n-3 (3,6,9-) are probably produced from linolenic acid [49]. Moths in the families Geometridae, Arctiidae, and Noctuidae apparently utilize linoleic and linolenic acid as precursors for their pheromones that must be obtained in the diet,since moths can not synthesize these fatty acids [50]. Most of the Type II pheromones are produced by chain elongation and decarboxylation to form hydrocarbons [51]. Oxygen is added to one of the double bonds in the polyunsaturated hydrocarbon to produce an epoxide [49]. 

The goal of this chapter is to provide an overview of the occurrence of Type II polyene pheromones and their derivatives, and their chemistry, including their biosynthesis and synthesis. The older literature in this subject area was reviewed in Millar (2000), and summarized more recently in Ando et al. (2004). Thus, this chapter will provide a comprehensive summary of all known Type II pheromone structures and their occurrence in Tables 1 1, whereas the text will focus more on work over the past ten years. The interested reader is further directed to three useful online databases, two of which focus on lepidopteran pheromones (www.tuat.ac.jp/ antetsu/review/e-List.pdf Ando, 2003 www-pherolist.slu. se/pherolist.php Witzgall et al., 2004) and the third of which covers insect pheromones in general (www.pherobase.com El-Sayed, 2008). 

Almost all known Type II pheromones are listed in Tables 18.1-18.4 (Arctiids, Geometrids, Noctuids, and Lymantriids, respectively). The few exceptions where Type II pheromones have been found in other lepidopteran families (e.g., Crambidae or Pyralidae) are discussed in the section below on taxonomic distribution of these compounds. 

The taxonomic distribution of Type II pheromones has been previously reviewed in some detail (Millar, 2000 Ando et al., 2004), and so I will focus only on the main patterns and trends, along with a discussion of more recent findings. The reader is also cautioned that these patterns and trends are heavily biased by the fact that the identification of lepidopteran pheromones has not been conducted methodically. Rather, species that are of economic importance have been most intensively studied for example, pheromones or sex attractants are known for hundreds of tortricid species, whereas few or no pheromones at all have been identified for members of other families (Ando et al., 2004). 

Second, the decarboxylase enzymes required to produce hydrocarbons apparently are not present in lepidopteran pheromone glands, but these enzymes are present in oenocyte cells where most insect hydrocarbon synthesis takes place (Blomquist et al., 1987). Thus, Lepidoptera that produce Type II pheromones must have a mechanism for transport of hydrocarbon pheromone components from the oenocytes to the pheromone gland, where... 

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