ABSTRACT
Devastating magnitudes of flood disasters have been occurring in various areas of Japan, and their impact has been increasing in recent years. Looking ahead, it is foreseen that rainfall and its patterns will be altered due to the climate change accompanied by global warming, and there is concern that the intensity and frequency of flood disasters might be exacerbated. This paper aims to introduce flood characteristics and management policies in Japan that have been undertaken for a long time in order to mitigate these recurrent flood disasters. It also highlights extremely devastating floods in some areas that occurred under recent climate variability, and to address the progress in the assessment of hydro-meteorological tendencies and in the promotion of dialogue among climatologists and hydrologists. Lastly, a new initiative to establish an intemational centre on water-related hazards and its risk management is presented.
Subject(s)
Disasters , Greenhouse Effect , Climate , Disaster Planning , Forecasting , Japan , Meteorological Concepts , Rain , Water MovementsABSTRACT
Human bcl-2 and bag-1 DNA were introduced into mouse hybridoma 2E3- O cells and expressed. The expression of bcl-2 in BCMGneo-bcl2 transfectants was confirmed by ELISA and that of bag-1 in pZeo-bag1 was confirmed by western blotting. In batch cultures, the over-expression of bcl-2 prolonged the culture period by 2 days and co-expression of bcl-2 and bag-1 prolonged the culture period by 3 days. The delayed increase in the dead cell number in culture of the bcl-2 and bag-1 cotransfectant indicated the additional antiapoptosis effect of bcl-2 and bag-1 cotransfection in comparison with the bcl-2 only transfection. The bcl-2 transfectants (2E3O-Bcl2) produced antibody twofold per batch culture in comparison with 2E3-O cells transfected with BCMGSneo (2E3O-Mock). Enhancement of this MoAb production was due to the improved survival of the cells and was not due to stimulation of antibody production rate per cell by Bcl-2 expression. And the bcl-2 and bag-1 co-transfectant (2E3O-Bcl2-BAG1) produced antibody approximately fourfold of 2E3O-Mock per batch culture. Enhancement of this MoAb production was due to the improved survival of the cells and was partly due to stimulation of MoAb production rate per cell in the non-growing phase by the cotransfection. The method to engineer hybridoma cells genetically with bcl-2 and bag-1 for increasing viability and productivity would be widely applied for improving antibody productivity of hybridoma cultures.
ABSTRACT
Sea urchin zygotes can be refertilized when they are deprived of the fertilization membrane and the hyaline layer. We have earlier reported that a transient increase of the intracellular Ca2+ concentration (Cai-transient) is induced in zygotes refertilized by sperm or treated with a sperm extract (spex) (M. Osawa et al., 1994, Dev. Biol. 166, 268-276). We investigated quantitative characteristics of the Cai-transient induced by sperm and spex, using a Ca2+ indicator, Indo-1. When sperm or spex was applied to zygotes, the peak value of the Cai-transient was 1.16 or 0.69 microM, respectively. Although these values were lower than the peak value of 1.95 microM measured during normal fertilization, the entire time courses of the three types of Cai-transients were similar. The Cai-transients during fertilization is known to be caused both by the IP3-induced Ca2+ release (IICR) and by a mechanism independent of IICR. The Cai-transients during refertilization and fertilization were not inhibited by an IP3 receptor inhibitor, heparin or by a G-protein inhibitor, GDPbetaS. However, heparin delayed the time courses of both Cai-transients. These results suggest that there may be two signal transduction pathways operating during refertilization, one dependent and the other independent of IICR. By contrast, both heparin and GDPbetaS inhibited the spex-induced Cai-transient. The IP3 content in spex-treated zygotes increased, and the spex-induced Cai-transient occurred even in the absence of external Ca2+. Cai-transient was not observed when spex was injected into zygotes. These data suggest that spex induces IICR in zygotes by activating certain cell surface receptors coupled to G-proteins.