Mechanism of the accumulation of free amino acids in seaweed with cell and tissue culture

1.以条斑紫菜自由丝状体相为实验藻类，研究了细菌对海藻中游离氨基酸积累的影响。用氨基酸分析仪测定氨基酸图谱。在Axnic和细菌污染的培养物之间获得了几乎相同的氨基酸图谱。而细菌污染藻类的游离氨基酸含量是Axnic藻类的1.4倍。因此，共生菌对游离氨基酸的积累负有责任。考察了生活史阶段、性别、育性和成熟度对游离氨基酸模式的影响。本研究中使用的藻类包括海带(雌、雄配子体、游动孢子囊体和孢子体)、裙带菜(雌、雄配子体、孢子体和孢子体)、条斑石藻(丝状体和菌体)、可育和不育的孔雀石。不同藻种在生活史阶段、性别、育性和成熟度等方面的游离氨基酸模式在数量和质量上存在较大差异。以日本对虾、羽衣藻属、条斑对虾为实验藻种，测定了藻类生长过程中游离氨基酸模式的变化。这些藻类的生长对游离氨基酸图谱没有影响。氨基酸含量随各海草生长发育呈现出特定的上升或下降趋势。以巨型共生绿藻--大叶橡胶藻为材料，研究了其乙醇提取物中含有相当数量的游离胱氨酸的游离氨基酸积累机理。在完整藻类的细胞液中，用高效液相色谱和硫醇特异性试剂荧光检测，检测到的是游离半胱氨酸，而不是半胱氨酸。当半胱氨酸合酶活性被测量时，瓦伦藻被发现具有非常强的活性(大约是其他藻类的5倍)。该酶定位于通过细胞分离获得的叶绿体中。

1. Effects of bacteria on the accumulation of free amino acids in seaweed were studied, using free living conchocellis phase of red alga Porphyra yezoensis as the experimental alga. Amino acid pattern was determined with amino acid analyzer. Almost the same amino acid pattern was obtained between axnic and bacteria-contaminated cultures. However, the amounts of free amino acid in bacteria-contaminated alga was 1.4-fold that of axnic one. The symbiotic bacteria, therefore, was responsible to the accumulation of free amino acids.2. Effects of the stage of life cycle, sex, fertility and maturation on the free amino acid pattern were examined. The algae used in this study were Laminaria japonica (female and male gametophytes, zoosporangial sori and sporophyte), Undaria pinnatifida (female and male gametophytes, sporophyte, and sporophyll), P.yezoensis (conchocelis phase and thalli), fertile and sterile Ulva pertusa. Free amino acid pattern differed very much in quantity and quality among the stage of life cycle, sex, fertility and maturation in each species of alga.3. Changes of free amino acid pattern during growth of algae were tested using L.japonica, U.pinnatifida, P.yezoensis as experimental algae. The growth of these algae did not affect to the free amino acid patters. However, the amino acid contents showed specific increasing or decreasing tendency with the growth of each seaweed.4. The mechanism of the accumulation of free amino acid was studied, using giant coenocytic green alga Valonia macrophysa which contains counsiderable amounts of free cystine in its ethanolic extracts. In the cell sap of the intact alga, free cysteine, not cystine, was detected using HPLC and fluorometric detection with thiol-specific reagent. When the cysteine synthase activity was measured, Valonia was found tohave very strong activity (about 5-fold) than the other algae. This enzyme localized in chloroplast obtained by cell fractionation.