New polar constituents of the pupae of the silkworm Bombyx mori L. I. Isolation and identification of methionine sulfoxide, methionine sulfone, and gamma-cyclic di-L-glutamate.
In addition to serine (L:D = 68:32), methionine sulfoxide (MSO), L-methionine sulfone (L-MSO(2)), and disodium gamma-cyclic di-L-glutamate were identified in a methanol extract of Bombyx mori L. pupae. MSO was isolated in a diastereomeric mixture of L(+)- and D(+)-MSO in a ratio of 99:1. The presence of these compounds in other developmental stages, including eggs, larvae (1st, 4th, 5th, and mature 5th instar), adults, and excrement (feces and urine) was investigated. The L(+)-isomer of MSO was present in extracts of the 1st and 5th instar larvae, adults, and eggs, but was not detected in feces or urine. The D(+)-isomer was found only in pupal stage extracts, and was excreted into the meconium with L(+)-isomer. L-MSO(2) and gamma-cyclic di-L-glutamate were not detected at other insect life stages or in the insect excrement. gamma-Cyclic di-L-glutamate is thought be produced due to blockage of the glutamate synthetic pathway (glutamine synthetase) by L-MSO(2) and Mg(2+). The biochemical role of L-MSO(2) during the pupal life stage remains unknown, but importantly, the stage-specific expression suggests that it is a candidate molecule for the induction of diapause.
Tanaka
Ryuichiro
R
Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Osaka, Japan. tanaka-r@pharm.setsunan.ac.jp
D000818:Animals; D012831:Bombyx / Q000737:chemistry* / Q000254:growth & development; D007814:Larva / Q000737:chemistry / Q000254:growth & development; D008715:Methionine / Q000031:analogs & derivatives* / Q000737:chemistry; D010456:Peptides, Cyclic / Q000737:chemistry*; D011679:Pupa / Q000737:chemistry / Q000254:growth & development
C527824:5,10-dioxo-1,6-diazacyclodecane-2,7-dicarboxylic acid; D010456:Peptides, Cyclic; C018332:methionine sulfone; D008715:Methionine; C013111:methionine sulfoxide