dictyNews
Electronic Edition
Volume 43, number 16
July 21, 2017
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Abstracts
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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 [[log in to unmask]]
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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 [[log in to unmask]]
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[End dictyNews, volume 43, number 16]
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