Format

Send to

Choose Destination
Proc Natl Acad Sci U S A. 2017 Jul 11;114(28):7266-7271. doi: 10.1073/pnas.1621469114. Epub 2017 Jun 27.

Force generation by groups of migrating bacteria.

Author information

1
Department of Mechanical and Aerospace Engineering, Princeton University, NJ 08544; b.sabass@fz-juelich.de shaevitz@princeton.edu.
2
Institute of Complex Systems 2, Forschungszentrum Jülich, D-52425 Juelich, Germany.
3
Lewis-Sigler Institute for Integrative Genomics, Princeton University, NJ 08544.
4
Joseph Henry Laboratories of Physics, Princeton University, NJ 08544.
5
Department of Mechanical and Aerospace Engineering, Princeton University, NJ 08544.
6
Lewis-Sigler Institute for Integrative Genomics, Princeton University, NJ 08544; b.sabass@fz-juelich.de shaevitz@princeton.edu.

Abstract

From colony formation in bacteria to wound healing and embryonic development in multicellular organisms, groups of living cells must often move collectively. Although considerable study has probed the biophysical mechanisms of how eukaryotic cells generate forces during migration, little such study has been devoted to bacteria, in particular with regard to the question of how bacteria generate and coordinate forces during collective motion. This question is addressed here using traction force microscopy. We study two distinct motility mechanisms of Myxococcus xanthus, namely, twitching and gliding. For twitching, powered by type-IV pilus retraction, we find that individual cells exert local traction in small hotspots with forces on the order of 50 pN. Twitching bacterial groups also produce traction hotspots, but with forces around 100 pN that fluctuate rapidly on timescales of <1.5 min. Gliding, the second motility mechanism, is driven by lateral transport of substrate adhesions. When cells are isolated, gliding produces low average traction on the order of 1 Pa. However, traction is amplified approximately fivefold in groups. Advancing protrusions of gliding cells push, on average, in the direction of motion. Together, these results show that the forces generated during twitching and gliding have complementary characters, and both forces have higher values when cells are in groups.

KEYWORDS:

Myxococcus xanthus; bacteria; gliding; traction force; twitching

PMID:
28655845
PMCID:
PMC5514709
DOI:
10.1073/pnas.1621469114
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center