Characterization of a germination-accelerating factor from the silkworm (Bombyx mori Linnaeus) of entomopathogenic fungus Nomuraea rileyi (Farlow) Samson.
The conidium of the entomopathogenic fungus, Nomuraea rileyi, has been found to germinate rapidly in the presence of a host insect-derived extract. This extract therefore appears to contain an important factor involved in host recognition by N. rileyi, although the substance (germination-accelerating factor, GAF) responsible for such unique germination behavior has yet to be identified. Our previous study was extended to the isolation of GAF from pupae of the silkworm, a host insect of N. rileyi. This present work subjects GAF to a structural analysis. The chemical structure of GAF is characterized as 2S-amino-tetradeca-4-ene-1,3R-diol (D-erythro-C(14)-sphingosine) based on spectroscopic data. An examination of the structure-activity relationship shows that the activity of D-erythro-C(14)-sphingosine was superior to that of sphingosines with shorter and longer carbon chains. It is suggested that the molecular species with a 14-carbon chain of a sphingosine is important for host recognition.
Kumamoto Prefectural Agriculture Research Center, Koshi, Kumamoto, Japan. noda-t-dw@pref.kumamoto.lg.jp
Takahiro
T
Noda
Masateru
M
Ono
Kazuhiko
K
Iimure
Tomohiro
T
Araki
D000818:Animals; D012831:Bombyx / Q000737:chemistry*; D006999:Hypocreales / Q000187:drug effects* / Q000254:growth & development*; D011679:Pupa / Q000737:chemistry; D013110:Sphingosine / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D013329:Structure-Activity Relationship
D013110:Sphingosine