[(18)O]-oxygen incorporation reveals novel pathways in spiroacetal biosynthesis by Bactrocera cacuminata and B. cucumis.
The origins of the oxygen atoms in 1,7-dioxaspiro[5.5]undecane (1) and hydroxyspiroacetal (2) from Bactrocera cacuminata, and in 2,8-dimethyl-1,7-dioxaspiro[5.5]undecane (3) and hydroxyspiroacetal (4) from B. cucumis, have been investigated by incorporation studies from both [(18)O(2)]-dioxygen and [(18)O]-water. Combined GC-MS examination and high-field NMR analysis have demonstrated that all oxygen atoms in 1 and 2 from B. cacuminata are dioxygen derived, but in contrast, the spiroacetals 3 and 4 from B. cucumis incorporate one ring oxygen from water and one ring oxygen (and the hydroxyl oxygen in 4) from [(18)O(2)]-dioxygen. These results reveal not only the generality of monoxygenase mediation of spiroacetal formation in Bactrocera sp., but also an unexpected complexity in their biosynthesis. A general paradigm accommodating these and other observations is presented.
Fletcher
Mary T
MT
Department of Chemistry and Centre for Magnetic Resonance, The University of Queensland, Brisbane 4072, Australia.
Wood
Barry J
BJ
Brereton
Ian M
IM
Stok
Jeanette E
JE
De Voss
James J
JJ
Kitching
William
W
D000080:Acetals / Q000378:metabolism*; D000818:Animals; D004175:Diptera / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010103:Oxygen Isotopes; D013141:Spiro Compounds / Q000378:metabolism*
D000080:Acetals; D010103:Oxygen Isotopes; D013141:Spiro Compounds; D010100:Oxygen