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Toxicity of two type II ribosome‐inactivating proteins (cinnamomin and ricin) to domestic silkworm larvae
Author(s) -
Wei Guoqing,
Liu RenShui,
Wang Qiong,
Liu WangYi
Publication year - 2004
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.20024
Subject(s) - ricin , bombyx mori , biology , ribosome inactivating protein , midgut , biochemistry , polyacrylamide gel electrophoresis , rna , ribosome , gel electrophoresis , microbiology and biotechnology , protein biosynthesis , larva , instar , enzyme , toxin , botany , gene
Cinnamomin and ricin are two type II ribosome‐inactivating proteins. They exhibited a different toxicity to domestic silkworm ( Bombyx mori ) larvae by oral feeding bioassay. The LC 50 of ricin to the silkworm larvae at third instar was much lower than that of cinnamomin. When the isolated 80S ribosome from domestic silkworm pupae was treated separately with the reduced cinnamomin or the reduced ricin, a specific RNA fragment (R‐fragment) was produced as characterized by 8 M urea‐denatured polyacrylamide gel (3.5%) electrophoresis. The purified A‐chains of both cinnamomin and ricin showed a slightly different RNA N‐glycosidase activity to the domestic silkworm pupal ribosome. It was proposed that the difference of their toxicity to domestic silkworm larvae was not related to their A‐chains but to the properties of their B‐chains. It was also found that the vomit obtained from the midgut of domestic silkworm larvae could hydrolyze these two proteins apparently to a similar extent. Arch. Insect Biochem. Physiol. 57:160–165, 2004. © 2004 Wiley‐Liss, Inc.