Identification of 30-kDa fat body protein of Sarcophaga peregrina larvae selectively phosphorylated in the presence of 20-hydroxyecdysone as ribosomal protein S6

Previously, we showed that 20-hydroxyecdysone induces selective phosphorylation of a fat body protein of Sarcophaga peregrina with a molecular mass of about 30,000 (30-kDa protein) (Itoh, K., Ueno, K., & Natori, S. (1985) Biochem. J. 227, 683-688). This paper describes the identification of this 30-kDa protein. From the electrophoretic profile of 40S ribosomal proteins on two-dimensional polyacrylamide gel electrophoresis, the 30-kDa protein was identified as S6.     

Migration inhibition by an agarose microdroplet assay: monitoring of tumor-associated antigens on a simian virus 40-induced sarcoma.

Macrophage migration inhibition assays, with a direct agarose microdroplet method, were used to monitor TAA activity of preparations of SV-40-induced mKSA cells. These preparations included cell-free crude membranes, papain-solubilized and NP40 detergent-solubilized membrane extracts from mKSA tumor cells. The assay was extremely sensitive and could detect migration inhibition reactivity with all three types of antigenic preparations with concentrations as low at 250 ng protein/ml. The reactivities were quite reproducible from experiment to experiment using the same or different lots of these antigen preparations, and the reactivities were specific in that peritoneal exudate cells from BALB/c mice, immunized with antigenically unrelated but syngeneic plasmacytomas, were not inhibited by these antigens. The results demonstrated the usefulness of this assay in rapidly detecting small concentrations of partially purified TAA preparations by using small number of immune cells.     

In vitro growth inhibition of human intestinal bacteria by sarcotoxin IA, an insect bactericidal peptide

Sacotoxin IA, an anti-microbial peptide of insects, inhibited the growth of harmful human intestinal bacteria such as Escherichia coli, Clostridium ramosum and Clostridium paraputrificum, in vitro. Interestingly, E. coli O157 which is well-known to cause food poisoning, was most sensitive to the peptide among the bacteria tested. The peptide, however, did not affect the growth of Bifidobacterium adolescentis, Bifidobacterium longum, Lactobacillus acidophilus, Enterococcus faecalis, Bacteroides thetaiotamicron, Bacteroides uniformis and Bacteroides ovatuss which are abundant in the intestines of healthy people. The evidence suggests that sarcotoxin IA could change the composition of the intestinal flora to improve human health.