CSM News Electronic Edition Volume 1, number 9 July 10, 1993 Please submit abstracts of your papers as soon as they have been accepted for publication by sending them to CSM-News@worms.cmsbio.nwu.edu. =========================================================================== ANNOUNCEMENT For those of you with access to Gopher (if you don't know what gopher is get the Biologists Guide to Internet in the Dicty anonymous ftp archive), all of the files in the CSM archive are now also available via gopher. Point your gopher client to "gopher.nwu.edu". Select the "FTP SITES" menu item, then select the "Northwestern University" menu item. Now just select the "Dicty" menu item. Gopher greatly simplifies gaining access to these files. Gopher clients are now available at most sites. Check with your computer center. =========================================================================== ABSTRACTS OF RECENTLY ACCEPTED PAPERS Analysis of cell cycle progression during the development of Dictyostelium and its relationship to differentiation Wolfgang Zimmermann, Cornelis J. Weijer. Zoologisches Institut, Universit Munchen, Luisenstrasse 14, 8000 Munchen 2, FRG. Accepted: Developmental Biology SUMMARY Labeling with the thymidine analog 5'Bromo-deoxy uridine has been used to folow cell cycling during development of the cellular slime mould Dictyostelium discoideum. The results show that cycling continues during development and that 75% of all cells from axenicaly grown cultures go through S phase. Although cell cycle progression is temporarily blocked in all cells during early aggregation, it is specifically reinitiated in prespore cells later in development. Prestalk cells do not reenter the cycle Pulse chase experiments indicate a close correlation between cell cycle phase at the onset of development and differentiation fate. Cells in S phase and early G2 differentiate preferentially into prestalk cells; cells in the later part of G2 differentiate into prespore cells. ----------------------------------------------------------------------- Three-Dimensional Waves of Excitation During Dictyostelium Morphogenesis (Chemotaxis/numerical simulations/selforganization/reaction- diffusion coupling) in press, PNAS Oliver Steinbock*, Florian Siegert+, Stefan C. Muller*, andCornelis J. Weijer+ * Max-Planck-Institut fur Ernahrungsphysiologie, Rheinlanddamm 201, D-4600 Dortmund 1, FRG, Tel. ++49 231 1206343, Fax ++49 231 1206389 + Zoologisches Institut, Universitat Munchen, Luisenstr. 14, D- 8000 Munchen 2, FRG, Tel. ++49 89 5902359, Fax ++49 89 5902450 Abstract Cells in Dictyostelium slugs follow well defined patterns of motion. We found that the chemotactic cell response is controlled by a scroll wave of messenger concentration in the highly excitable prestalk zone of the slug, which decays in the less excitable prespore region into planar wave fronts. This phenomenon is investigated by numerical solutions of partial differential equations, which couple local nonlinear kinetics and diffusive transport of the messenger. In the interface of both regions a complex twisted scroll wave is formed, which reduces the wave frequency in the prespore zone. The spatio- temporal dynamics of waves and filaments are followed over 33 periods of rotation. ========================================================== [[END CSM-News, Volume 1, number 9]]