Bioengineers and physicists at the University of California San Diego, in a paper published in the current issue of the Proceedings of the National Academy of Sciences, have begun to address these fundamental questions.
The UC San Diego scientists focused their research on dense colonies of the rod-shaped bacteria Escherichia coli. By analyzing the spatial organization of the bacteria in a microfluidic chemostat – a kind of mini-circuit board for liquids rather than electrons – they found that growth and expansion of a dense colony of cells leads to a dynamic change from relative disorder to a remarkable re-orientation and alignment of the rod-like cells.
That finding, described in their paper “Biomechanical Ordering of Dense Cell Populations,” allowed them to develop a model of collective cell dynamics, and to use this model to “elucidate the mechanism of cell ordering, and quantify the relationship between the dynamics of cell proliferation and the spatial structure of the population.”
One of the authors, Lev S. Tsimring, at UC San Diego’s Institute of Nonlinear Science, explained the bioengineers’ use of bacteria to study the biomechanical ordering of cells.
“When environmental conditions are harsh, bacteria like to stick together. The most typical form of bacterial organization in nature is a biofilm: a dense quasi-two-dimensional colony of bacteria. Biofilms grow in and on living tissues, the surfaces of rocks and soils, and in aquatic environments,” he said, “but they’re also found in man-made systems and devices such as industrial piping and artificial implants. And bacteria are known to actively migrate toward surfaces and small cavities, where they form high-density colonies.”
At low densities, he said, bacteria and other cells communicate “remotely” by sending chemical signals – “chemotaxis” – but, as they aggregate and form dense communities, direct biomechanical contacts play a bigger and bigger role in how they organize themselves.
“Although previous studies have explored the complex signaling mechanisms in the early stages of biofilm formation,” Tsimring said, “the biomechanics of direct cellular contacts have received little attention. We focused, therefore, on the structure and dynamics of a growing two-dimensional colony of non-motile bacteria.”
His fellow researcher, Jeff Hasty, at the Institute for Nonlinear Science and UC San Diego’s Department of Bioengineering, said the team’s work provides a multiscale description of cell colony growth.
“Our results reveal how cell growth and colony expansion trigger the formation of the orientational order in the population,” Hasty said, “which, in turn, affects the mechanical and biochemical properties of the colony.”
The details of their research, the authors say, helps scientists understand how the local interaction of elementary components leads to collective behavior and the formation of a highly organized system.
Tsimring and Hasty collaborated with Scott Cookson, of the Department of Bioengineering, and Dmitri Volfson, now at Rosetta Inpharmatics LLC.
Funding for the research was provided by the National Institutes of Health, the National Science Foundation, and UC MEXUS-CONACYT.
Paul K. Mueller | Newswise Science News
Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH
Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences