dictyNews Electronic Edition Volume 43, number 16 July 21, 2017 Please submit abstracts of your papers as soon as they have been accepted for publication by sending them to dicty@northwestern.edu or by using the form at http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit. Back issues of dictyNews, the Dicty Reference database and other useful information is available at dictyBase - http://dictybase.org. Follow dictyBase on twitter: http://twitter.com/dictybase ========= Abstracts ========= Contact enhancement of locomotion in spreading cell colonies Joseph d’Alessandro1†, Alexandre P. Solon2, Yoshinori Hayakawa3, Christophe Anjard1,François Detcheverry1, Jean-Paul Rieu1 and Charlotte Rivière1 1 : Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France. 2: Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. 3 : Center for Information Technology in Education, Tohoku University, Sendai 980-8578, Japan. †Present address: Institut Jacques Monod (IJM), CNRS UMR 7592 and Université Paris Diderot, 75013 Paris, France Nature Physics Published online: 3 July 2017 DOI: 10.1038/NPHYS4180 full-text access to view-only version of the manuscript :http://rdcu.be/tUZU The dispersal of cells from an initially constrained location is a crucial aspect of many physiological phenomena, ranging from morphogenesis to tumour spreading. In such processes, cell–cell interactions may deeply alter the motion of single cells, and in turn the collective dynamics. While contact phenomena like contact inhibition of locomotion are known to come into play at high densities, here we focus on the little explored case of non-cohesive cells at moderate densities. We fully characterize the spreading of micropatterned colonies of Dictyostelium discoideum cells from the complete set of individual trajectories. From data analysis and simulation of an elementary model, we demonstrate that contact interactions act to speed up the early population spreading by promoting individual cells to a state of higher persistence, which constitutes an as-yet unreported contact enhancement of locomotion. Our findings also suggest that the current modelling paradigm of memoryless active particles may need to be extended to account for the history-dependent internal state of motile cells. submitted by: Charlotte Rivière [charlotte.riviere@univ-lyon1.fr] ——————————————————————————————————————— Fat-containing cells are eliminated during Dictyostelium development Jessica M. Kornke and Markus Maniak Abteilung Zellbiologie, Universität Kassel, D-34109 Kassel, Germany Biology Open, accepted Triacylglycerol is a universal storage molecule for metabolic energy in living organisms. However, Dictyostelium amoebae, that have accumulated storage fat from added fatty acids do not progress though the starvation period preceding the development of the durable spore. Mutants deficient in genes of fat metabolism, such as fcsA, encoding a fatty acid activating enzyme, or dgat1 and dgat2, specifying proteins that synthesize triacylglycerol, strongly increase their chances to contribute to the spore fraction of the developing fruiting body, but lose the ability to produce storage fat efficiently. Dictyostelium seipin, an orthologue of a human protein, that in patients causes the complete loss of adipose tissue when mutated, does not quantitatively affect fat storage in the amoeba. Dictyostelium seiP knockout mutants have lipid droplets that are enlarged in size but reduced in number. These mutants are as vulnerable as the wildtype when exposed to fatty acids during their vegetative growth phase, and do not efficiently enter the spore head in Dictyostelium development. submitted by: Markus Maniak [maniak@uni-kassel.de] ============================================================== [End dictyNews, volume 43, number 16]