An investigation of the genes that govern spore formation in the bacteria B. subtilis shows that chance plays a significant role in determining which of the microbes sacrifice themselves for the colony and which go on to form spores.
B. subtilis, a common soil bacteria, is a well-known survivor. When running short of food, it can alternatively band together in colonies or encase itself in a tough, protective spore to wait for better times. In fact, B. subtilis is so good at making spores that it's often used as a model organism by biologists who study bacterial spore formation.
"It's too early to say whether B. subtilis is truly altruistic," said co-author Oleg Igoshin, assistant professor of bioengineering at Rice University. "What is clear from this is that not all bacteria are going to look and act the same, and that's something that can be overlooked when people either study or attempt to control bacteria with population-wide approaches."
For example, Igoshin said doctors and food safety engineers might need to amend general approaches aimed at controlling bacteria with more targeted methods that also account for the uncharacteristic individual.
The new results appear in the April 15 issue of Molecular Systems Biology. The experimental work, which was done by Jan-Willem Veening, currently at Newcastle University, and by other members of Oscar Kuipers' research group at the University of Groningen in the Netherlands, focused on the B. subtilis genes that regulate both spore formation and the production cycles of two proteins -- subtilisin and bacillopeptidase. These two proteins help break apart dead cells and convert them into food. They are produced and released into the surrounding environment by B. subtilis cells that are running low on food.
From previous studies, scientists know there is some overlap between genes that control the production of the two proteins and those that control spore formation.
"Only a portion of the bacteria in a colony will form spores and only portion of the bacteria produce subtilisin, and we were interested in probing the genetic basis for this," Igoshin said. "How is it decided which cells become spores and which don't?"
Igoshin, a computational biologist, used computer simulations to help decipher and interpret the team's experimental results. He said the team found that fewer than 30 percent of individuals in a colony produce large quantities of the food-converting proteins. Even though the proteins benefit all members of the colony and help some cells to become spores, the cells that produce the proteins in bulk do not form spores themselves.
"There's a feedback loop, so that cells that start producing the proteins early get a reinforced signal to keep making them," Igoshin said. "We found that it's probabilistic events -- chance, if you will -- that dictates who is early and who is late. The early ones start working for the benefit of everyone while the later ones save valuable resources to ensure successful completion of sporulation program. Many cells will end up committing to sporulation before they had a chance to contribute to protease production"
Igoshin said a key piece of evidence confirming modeling predictions came in experiments that tracked genetically identical sister cells, some of which became protein producers and some of which didn't.
Jade Boyd | EurekAlert!
What happens in the cell nucleus after fertilization
06.12.2016 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
06.12.2016 | Materials Sciences
06.12.2016 | Medical Engineering
06.12.2016 | Power and Electrical Engineering