Report on the Activities under the Auspices of the JSPS's Invitation Program of Foreign Eminent Scientists

    According to the program of this year, which followed the last year's, Konan University invited again Dr Yoshio Masui, Professor Emeritus, University of Toronto, Canada, during the period of September 5 to December 1, 2003. The account of the activities of this year will be briefly reported as follows:

1.    Exchanges of Academic and Scientific Activities.

    (1) Exchanges within the Konan University
    A seminar was held for teachers and students of the Department of Biology on November 8. The theme was "Cell Cycle Changes during Development", in which Dr Masui presented his recent research in an easily comprehensible way, and was engaged in active discussions to exchange opinions with audience. Also he attended Prof. Sonobe' weekly lab seminars as well as the graduate course "Animal Physiology and Biochemistry" to give valuable advices to students on their research. Further, he gave guidance to graduate students for preparing papers as well as writing English for publication.

    (2) Exchanges with other Universities
    Dr Masui attended the 74th Annual Meeting of Japanese Society of Zoologists (September 17-19, Hakodate City), and gave a speech entitled "Cytostatic Factor (CSF) in Unfertilized Animal Egg: History and Perspective of the Research" in the symposium on "MI Arrest in Oocyte Maturation: CSF Research in New Perspectives".Also he visited Department of Science, Graduate School, Hokkaido University (Prof. Emeritus Katagiri) on September 20 to discuss research problems. Further, Dr Masui visited Kumamoto University to give a seminar speech entitled " Cell Cycle Changes in Developmental Processes" in School of Medicine (Prof. Yamamura) and in Faculty of Science (Prof. Abe). Then, he visited Kyusyu University and gave a seminar of the same title in the Department of Science, Graduate School (Prof. Sagata). Dr.Masui also visited Department of Biology, Yamaguchi University (Prof. Iwao) to discuss research problems on November 25.

2.    Co-operative Research.

    According to the research program entitled "Cell Biological Investigation into Parthenogenesis and Bisexual Reproduction in Daphnia", analyses ware carried out with special reference to influences of environmental factors and hormones on the mechanisms of sex determination and the formation of permanent eggs (dormant eggs). When Daphnia magna, which were propagate only through parthenogenesis by females, ware exposed to a crustacean juvenile hormone, methyl farnesoate (MF), rate of male production was increased in a concentration-dependent manner. When MF was applied to animals at different stages of oogenesis, it was found that MF acted most effectively during the period of yolk accumulation. In order to clarify whether or not MF could actually be biosynthesized in the body of Daphnia magna, the reaction that methylates farnesoic acid (the last step of MF biosynthesis) was examined using 3H-methyl methionine. Thus, it became evident that D. magna did biosynthesize MF. All in all, the results obtained suggest that MF and its analogues act on Daphnia as endocrine-disturbing agents. These research results ware presented, being entitled "The Endocrine Mechanism Involved in Sex Determination in Daphnia", at the 74th Annual Meeting of Japanese Society of Zoologists (September 17-19, Hakodate City). Further, they were published as review article entitled "An Endocrinological Approach to the Mechanism of Alterations in Sex Determination and Reproductive Pattern of Daphnia magna" in Comparative Endocrinological Society News (Vol.111, pp.4-10, 2003).