1993 Fiscal Year Final Research Report Summary
An approach to the biochemical mechanisms of heartwood formation using cell cultures
| Project/Area Number |
03454081
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
林産学
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| Research Institution | KYUDHU UNIVERSITY |
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Principal Investigator |
SAKAI Kokki Kyushu University, Department of Forest Products, Professor, 農学部, 教授 (30015656)
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| Co-Investigator(Kenkyū-buntansha) |
TSUTSUMI Yuji Shizuoka University, Department of Forest Resources Science, Research Associate, 農学部, 助手 (30236921)
SHIRAISHI Susumu Kyushu University, Department of Forest Products, Associate Professor, 農学部, 助教授 (70226314)
KONDO Ryuichiro Kyushu University, Department of Forest Products, Associate Professor, 農学部, 助教授 (80091370)
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| Project Period (FY) |
1991 – 1993
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| Keywords | Cupressaceae / Heart wood / Thujaplicin / Hinokitiol / Biosynthesis / Elicitor / Mevaronate pathway / Cupressus lusitanica |
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| Research Abstract |
(1). Biochimistry of lignification
Lignification process has been investigated in this project since it occurs prior to the heartwood formation in forest tree cells. A peroxidase isoenzyme was found to catalyze substrate specifically the dehydrogenetive polymerization of sinapyl alcohol. This enzyme was isolated and characterized from cell cultures of Populus alba.
(2). Establishment of cell cultures that produce heartwood constituents
Callus cultures of Cupressus lusitanica (Cupressanceae) and Pinus spp. produced their heartwood constituents, beta-thujaplicin and pinosylvins, respectively, although no heartwood constituents were detected in calluses of Cryptomeria japonica and Chamaecyparis obtusa. Thus, the culture of C.lusitanica cells is regarded as a good experimental material for studying phenomena of heartwood formation.
(3). Elicitor of beta-thujaplicin accumulation in callus cultures
The addition of yeast extract to callus cultures of C.lusitanica leads to a large increase in the p
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roduction of beta-thujaplicin that act as a phyoalexin of the treated cultures. The extract was fractionated by means of ethanol precipitation, ribonucleasetreatment, gel permiation choromatography and Cu-complexation. The most effective fraction was a polysaccharide composed of maily mannose and glucose.
(4). Biosythetic pathway of beta-thujaplicin
Callus cultures of C.lusitanica was fed with ^<14>C-mevaronate, ^<14>C-glucose or ^<14>C-malonate by the shot-gun method. Elicitor was added to the callus at the same time. The results proved that beta-thujaplicins synthsized via the mevaronate pathway.
(5). An attempt to isolation of the key enzyme(s) for beta-thujaplicin biosynthesis
We tried to isolate any enzyme(s) that catalyze biosynthesis of beta-thujaplicin from isopentenyl pyrophosphate. However, such enzyme(s) have not been detected in cell-free extract of callus cultures of C.lusitanica. Isoltion of the key enzyme(s), its characterization and proof of its presence in transition zone of C.lustanica trees should be subjects to be solved in the near future. Less
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