During the course of a study of leguminous plants, cytotoxicity was demonstrated by the crude saponin fraction of Albizia julibrissin. Following chromatographic purification, the structures of three novel saponins, julibrosides I-III (1-3), inclusive of a cytotoxic principle, were elucidated. A comparison of the cytotoxicity of julibrosides (1-3) and their prosapogenins (4-15) prepared by alkaline hydrolysis clearly indicated that both an alpha-L-arabinofuranosyl-(1-->4)-[beta-D-glucopyranosyl-(1-->3)]-alpha- L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl ester unit and a monoterpene-quinovopyranosyl moiety are crucial substituents for cytotoxicity among this class of compounds. The hydroxy group at C-16 of aglycon may play an important role in mediating cytotoxicity, and the N-acetyl-glucosamine moiety at C-3 seems to enhance activity because 3 showed the strongest cytotoxicity.

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Bicyclomycin is a new antibiotic obtained from the culture filtrate of Streptomyces sp. WS4545 which was identified as a new species and given the nameStreptomyces sapporonensis. Its elementary analysis and mass spectroscopic measurement suggest that the molecular formula is C12H18N2O7. There is no specific ultraviolet absorption. Bicyclomycin is active against Gramnegative bacteria, especially Escherichia colt, Klebsiella, Shigella and Salmonella species, and has no cross resistance with the usual antibiotics. It has low toxicity in mice.

Recrystallization of polycrystalline silicon (poly-Si) film by excimer laser annealing (ELA) is discussed by considering the experimental results that the three stages of nucleation, textured grain growth and secondary grain growth were observed. Although the phenomenon of nucleation in the amorphous silicon (a-Si) is understood by considering crystallization from the super cooled liquid, the growth mechanisms of the textured grain and secondary grain are not understood by this, because the melting point of poly-Si which has already been formed on the entire surface during these growth stages is higher than that of a-Si. The recrystallization mechanism considering the dislocation movement is introduced to investigate the present phenomenon. It also clarifies the reason why secondary grain growth occurs under the critical conditions of laser irradiation energy and shot number. The feasibility of nucleation through the super cooled liquid is also discussed.