PATHWAY OF TERPENE EXCRETION BY THE APPENDIX OF SAUROMATUM-GUTTATUM

Electron microscopy of the cells of the thermogenic appendix of Saurom atum guttatum has revealed a fusion event between pocket-like structur es of the rough endoplasmic reticulum (rER) and the plasma membrane. A s a result of the fusion event, many regions of the plasma membrane ha ve paired unit membranes (four leaflets instead of two). The fusion al lows the transfer of osmiophilic material from the rER pockets to the plasma membrane, where the osmiophilic material is confined to bilayer , pocket-like structures. A clear correlation is found between the pre sence of the osmiophilic compound and sesquiterpenes. Prior to heat pr oduction, the rER- and plasma-membrane pockets are electron dense, and sesquiterpenes are detectable only in tissue extracts. On the day of heat production, electron-translucent pockets are subsequently found a nd the stored sesquiterpenes are released to the atmosphere. Three ses quiterpenes have been identified by gas chromatography-mass spectromet ry as alpha-copaene and beta- and alpha-caryophyllene.