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Quality Evaluation of Tomato Fruits by Specific Gravity and Color 

By Wenzhong Hu, Hayato Yasutake, Toshitaka Uchino, Eriko Yasunaga, Daisuke Hamanaka, Yoshiaki Hori, 敏剛 内野, 円理子 安永, 大介 濱中 and 善昭 堀


A hybrld protein was synthesized by connecting bovine ribonuclease A (RNase A), an enzyme, and B chain of ricin, a toxic lectin from castor bean seeds, with a disulfide bridge. The preparation purified was revealed to contain one mole of RNase A and one mole of ricin B chain. The ricin B-RNase A hybrid was tested for cell binding, cellular uptake, and intoxication in four kinds of cells, rat liver and testis Leydig cells (normal and primarily cultured cells), and HeLa and BeWo cells (transformed cells). The ricin B-RNase A hybrid inhibited cellular protein synthesis equally in all four cells, while incubation of each cell mentioned above with RNase A or ricin B chain alone neither gave effect on cellular protein synthesis nor cell viability. This result inffered that the ricin B-RNase A hybrid first bound to the cell surface, internalized followed by the release of RNase A from the hybrid, resulting in the destruction of RNAs which play important roles in cellular protein synthesis. The degree of internalization of the ricin B-RNase A hybrid into cells was almost equal in four types of cells, about 10% of the bound hybrid. However, this value was about 1/3~1/2 that of ricin, a toxic lectin composed of A and B chains. From these results, ricin B-containing hybrid may be used as a universal tool to deliver a biologically active protein to a large number of different cells

Topics: Gravity, Brix value, Tomato fruits, Malic acid
Publisher: 九州大学農学部
Year: 2002
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