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Induction of cuticular melanization in Spodoptera littoralis larvae by PBAN/MRCH: Development of a quantitative bioassay and structure function analysis
Author(s) -
Altstein Miriam,
Gazit Yoav,
Aziz Orna Ben,
Gabay Tal,
Marcus Ruth,
Vogel Zvi,
Barg Jacob
Publication year - 1996
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/(sici)1520-6327(1996)31:4<355::aid-arch1>3.0.co;2-v
Subject(s) - biology , bioassay , larva , function (biology) , botany , zoology , ecology , microbiology and biotechnology
PBAN (also termed melanization and reddish coloration hormone, MRCH) is a cerebral factor known to regulate sex pheromone biosynthesis and cuticular melanization in moths. In the present study we developed a quantitative method (based on computerized image analysis of cuticles) to determine the effect of Helicoverpa zea PBAN (Hez‐PBAN) on cuticular melanization and to study the structure‐activity relationship of the neuropeptide in Spodoptera littoralis larvae. The results indicate that Hez‐PBAN stimulates cuticular melanization in an interspecific manner, and that the minimal dose evoking formation of melanins is between 3–10 pmol/larva. Higher doses of Hez‐PBAN did not stimulate melanization any further. Examination of the structure‐activity relationship of Hez‐PBAN revealed that the first eight N‐terminal amino acids are not essential for the melanotropic activity and that the activity resides in the C‐terminal region. Within this region the C‐terminal amide was found to play a very important role. © 1996 Wiley‐Liss, Inc.