Nav: Home

Bacteria are individualists

May 12, 2016

No two bacteria are identical - even when they are genetically the same. A new study from researchers from Eawag, ETH Zurich, EPFL Lausanne, and the Max Planck Institute for Marine Microbiology in Bremen reveals the conditions under which bacteria become individualists and how they help their group grow when times get tough.

Whether you are a human or a bacterium, your environment determines how you can develop. In particular, there are two fundamental problems: What resources can you draw on to survive and grow and how do you respond if your environment suddenly changes?

The researchers recently discovered that the number of individualists in a bacterial population goes up when its food source is restricted. Their finding goes against the prevailing wisdom that bacterial populations merely respond, in hindsight, to the environmental conditions they experience. Individualists, the study finds, are able to prepare themselves for such changes well in advance.

Scarcity fosters diversity

In a recent paper, researchers working with Frank Schreiber have shown that individual cells in bacterial colonies can differ widely in how they respond to a lack of nutrients. Although all of the cells in a group are genetically identical, the way they process nutrients from their surroundings can vary from one cell to another. For example, bacteria called Klebsiella oxytoca preferentially take up nitrogen from ammonium, as this requires relatively little energy. When there isn't enough ammonium for the entire group, some of the bacteria start to take up nitrogen by fixing it from elementary nitrogen, even though this requires more energy. If the ammonium suddenly runs out altogether, these cells at least are prepared. While some cells suffer, the group as a whole can continue to grow. "Although all of the bacteria in the group are genetically identical and exposed to the same environmental conditions, the individual cells differ among themselves," says Schreiber.

Schreiber and his colleagues were only able to reveal the astonishing differences between the bacteria by studying them very closely. "We had to measure nutrient uptake by individual bacterial cells - even though these are only two Mikrometers large," explains Schreiber. "Usually, microbiologists study the collective properties of millions or even billions of bacteria. It was only thanks to the close collaboration between the research groups, and by pooling our expertise and technical equipment, that we were able to study the bacteria in such detail.

Diversity promotes flexibility

The present study shows to what extent individuality - in bacteria and in general - can be essential in a changing environment. Differences between individuals give the group new properties, enabling it to deal with tough environmental conditions. "This indicates that biological diversity does not only matter in terms of the diversity of plant and animal species but also at the level of individuals within a species," says Schreiber.

Next, Schreiber and his colleagues plan to study whether the individualistic behavior of specific individuals is of equal importance in natural environments.
-end-
Original publication

Frank Schreiber, Sten Littmann, Gaute Lavik, Stéphane Escrig, Anders Meibom, Marcel Kuypers, Martin Ackermann

Phenotypic heterogeneity driven by nutrient limitation promotes ?growth in fluctuating environments.

Nature Microbiology (2016)

doi:10.1038/nmicrobiol.2016.55

Max-Planck-Gesellschaft

Related Bacteria Articles:

Conducting shell for bacteria
Under anaerobic conditions, certain bacteria can produce electricity. This behavior can be exploited in microbial fuel cells, with a special focus on wastewater treatment schemes.
Controlling bacteria's necessary evil
Until now, scientists have only had a murky understanding of how these relationships arise.
Bacteria take a deadly risk to survive
Bacteria need mutations -- changes in their DNA code -- to survive under difficult circumstances.
How bacteria hunt other bacteria
A bacterial species that hunts other bacteria has attracted interest as a potential antibiotic, but exactly how this predator tracks down its prey has not been clear.
Chlamydia: How bacteria take over control
To survive in human cells, chlamydiae have a lot of tricks in store.
More Bacteria News and Bacteria Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#534 Bacteria are Coming for Your OJ
What makes breakfast, breakfast? Well, according to every movie and TV show we've ever seen, a big glass of orange juice is basically required. But our morning grapefruit might be in danger. Why? Citrus greening, a bacteria carried by a bug, has infected 90% of the citrus groves in Florida. It's coming for your OJ. We'll talk with University of Maryland plant virologist Anne Simon about ways to stop the citrus killer, and with science writer and journalist Maryn McKenna about why throwing antibiotics at the problem is probably not the solution. Related links: A Review of the Citrus Greening...