studies on the agglutinins of marine algae from Taiwan

• Main Authors: Liao Woan-Ru, 廖婉茹
• Other Authors: Huang Rang
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/69379494185906793862

博士 === 國立臺灣大學 === 海洋研究所 === 88 === Abstract Agglutinins are widely distributed in nature. They are capable of agglutinating erythrocytes and other normal or transformal cells and often used in the studies for biomedical purposes. In this study, thirty species of marine macroalgae, collected from the northeastern coast of Taiwan, and marine unicellular algae were assayed for hemagglutination, followed by isolation and purification of agglutinins in the selected algae. Algal extracts in both phosphate buffer saline (PBS) and aqueous ethanol were assayed for agglutination against erythrocytes of both human normal blood groups, i.e. A,B,O,AB, and blood with coagulation disorder as well as against rate, sheep and monkey erythrocytes. The results indicate that all of the marine algae assayed can agglutinate human and animal erythrocytes. Of the macroalgae, Eucheuma serra (red alga), Ulva fasciata (green alga) and Sargassum duplicatum (brown alga) are most prominent for such agglutination, reaching 212 titers. Extract of Gracilaria lemaneiformis (red alga) is less active in hemagglutination, but it has strong afinity for B erythrocytes. Marine microalgae also contain agglutinins, with activity generally higher activity than that for macroalage. Tretreatment of erythrocytes with pronase or trypsin for 2-6 hr improves markedly the detection of algal activity in general. Moreover, algal extracts remain active in agglutination at 45 ℃. The assayed microalgae have no requirement for divalent cations in hemagglutination. Agglutinating activity of crude algal extracts decreased markedly during the storage at 4 ℃ and —20 ℃ for 6-12 months. The agglutinin of Eucheuma serra (ESA) was isolated by DEAE Column, containing 10.2 mg protein/g dry wt of algal powder, with a band of 29,000 on SDS-PAGE. ESA has the specific binding affinity for mono- and oligosaccharides. Moreover, the isolated protein from the red alga Galaxaura marginata demonstrates hemolysis activity, with molecular weight of 26,000 Kda. The protein also binds mono- and oligosaccharides. Further assay was employed for the detection of plant glycoprotein in algal extracts using antibodies of wheatgerm agglutinin (WGA) and concanavalin A (Con A) in ELISIA plate and western blotting. In light of the generally strong activities, both marine macroalgae and microalgae are a potent source of lectins for study in biochemistry and medical applications. Some of the algal agglutinins probably have played important roles in algal biology and ecology.