The novel pathway of melanosis on crustaceans and its prevention.
Grant-in-Aid for Scientific Research (B)
|Allocation Type||Single-year Grants|
|Research Institution||Kyoto university|
HIRATA Takashi Kyoto university, Graduate school of agriculture, professor, 農学研究科, 教授 (40273495)
SUGAWARA Tatsuya Kyoto university, Graduate school of agriculture, Associate professor, 農学研究科, 助教授 (70378818)
KINOSHITA Masato Kyoto university, Graduate school of agriculture, Assistant professor, 農学研究科, 助手 (60263125)
ITO Shosuke Fujita health university, School of health sciences, professor, 衛生学部, 教授 (70121431)
WAKAMATSU Kazumasa Fujita health university, School of health sciences, professor, 衛生学部, 教授 (80131259)
|Project Period (FY)
2004 – 2006
Completed(Fiscal Year 2006)
|Budget Amount *help
¥15,600,000 (Direct Cost : ¥15,600,000)
Fiscal Year 2006 : ¥3,900,000 (Direct Cost : ¥3,900,000)
Fiscal Year 2005 : ¥4,700,000 (Direct Cost : ¥4,700,000)
Fiscal Year 2004 : ¥7,000,000 (Direct Cost : ¥7,000,000)
|Keywords||Crustaceans / Melanosis / Melanin / Prawns / Hemocyanin / Phenoloxidase / Carbon dioxide / Pheomelanin / クルマエビ / 冷凍エビ / クチクラ|
The objectives of this work were to clarify the properties of hemocyanin from kuruma prawn, which shows phenoloxidase activity, especially in fronzen-thawed prawns and to develop a novel method to prevent the melanosis on prawns.
1. Hemocyanin was purified from hemolymph and cuticle. The activated hemocyanin oxidized diphenols including DOPA to produce an intermediate product DOPAchrome. Hemocyanin also catalyzed the same reaction when monophenols (tyrosine etc.) were tested as substrates.
2. Immunolocalization of hemocyanin and the blackspot development in the exoskeleton were first confirmed.
3. Induction period was clearly observed when tyrosine was oxidized by hemocyanin. The very slow rate of monophenol oxidation was responsible for the wrong conclusion that hemocyanin has no activity against monophenols
4. Trace amounts of DOPA drastically accelerated the reaction of tyrosine with oxygen catalyzed by hemocyanin. The rapid blackening observed on frozen-thawed prawns was due to monophenol oxidation stimulated by trace diphenols in prawns.
5. Carbon dioxide effectively inhibited the black spot development. Little development of black spot was observed on prawns treated with the gas for a specified period.
6. An analytical condition of pheomelanin in prawns was established. Preliminary experiments showed that pheomelanin was accumulated in prawns up to 50% among total melanins.
Research Products (15results)