Nav: Home

Unconventional cell division in the Caribbean Sea

October 11, 2016

Most bacteria divide by placing a protein called FtsZ at the division site. Traditionally, it was thought that FtsZ must organize into a ring in order to recruit a dozen of other proteins and together with them exert an homogeneous and simultaneous constricting force pinching the bacterium from side to side. Just as when one tries to squeeze a rod-shaped air-balloon with a thumb and a ring finger. Although it is still debated which one - among the division complex proteins - is generating the constricting force, it has never been debated that FtsZ forms a ring. Be it made by continuous FtsZ filaments or by short and partly overlapping ones, be it patchy, elliptic or toroid, a ring has been long believed to be sine qua non for cell division.

Bacterial cell biology textbooks have been written by studying microorganisms that can be grown in the laboratory. However, most microbes are not cultivable yet and can only be observed in their natural environment. This is the case of microbes engaging in intimate associations with multicellular organisms.

Silvia Bulgheresi and her team study the bacteria that grow and reproduce on the surface of a small family of marine nematodes, the Stilbonematinae. It is on those occurring around a tropical island in the middle of the Caribbean that the unconventional microbe was discovered. The analysis of this bacterium, the symbiont of the marine nematode Robbea hypermnestra reinvigorates the discussion about how the constrictive force that drives bacterial cell division is generated.

The symbiont is a roughly 1 x 3 μm rod-shaped bacterium attached with one pole to the surface of its nematode host. First weird thing it does, is to orient its division plane parallel to its long axis, which makes it divide longitudinally instead of transversally (like conventional rod-shaped bacteria do). But as if building a wall and pinching a membrane over an approximately three times longer distance were not challenging enough, this resourceful organism tops it up by dividing asynchronously. Namely: it first invaginates at the nematode-attached pole and then at its free pole. "But the biggest surprise came as we searched for the FtsZ ring and we found none" explains Nikolaus Leisch, first author of the paper and currently a Postdoc at the Max Plank Institute, Bremen.

The division of the R. hypermnestra symbiont leaves the dazzled scientists at a loss to know which kind of evolutionary advantage this quirky division might bring. One possible explanation is that this would allow the symbiont to remain faithful to its worm host. "Longitudinal division might have evolved to transmit host attachment to both daughter cells. In other words, to avoid that one daughter cell is lost to the sand or the sea", speculates Bulgheresi.
-end-
Publication in Nature Microbiology: Asynchronous division by non-ring FtsZ in the gammaproteobacterial symbiont of Robbea hypermnestra: Nikolaus Leisch, Nika Pende, Philipp M. Weber, Harald R. Gruber-Vodicka, Jolanda Verheul, Norbert O. E. Vischer, Sophie S. Abby, Benedikt Geier, Tanneke den Blaauwen and Silvia Bulgheresi in Nature Microbiology (2016)
DOI: 10.1038/nmicrobiol.2016.182

University of Vienna

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.
Stress may protect -- at least in bacteria
Antibiotics harm bacteria and stress them. Trimethoprim, an antibiotic, inhibits the growth of the bacterium Escherichia coli and induces a stress response.
'Pulling' bacteria out of blood
Magnets instead of antibiotics could provide a possible new treatment method for blood infection.
New findings detail how beneficial bacteria in the nose suppress pathogenic bacteria
Staphylococcus aureus is a common colonizer of the human body.
Understanding your bacteria
New insight into bacterial cell division could lead to advancements in the fight against harmful bacteria.
Bacteria are individualists
Cells respond differently to lack of nutrients.

Related Bacteria Reading:

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

Changing The World
What does it take to change the world for the better? This hour, TED speakers explore ideas on activism—what motivates it, why it matters, and how each of us can make a difference. Guests include civil rights activist Ruby Sales, labor leader and civil rights activist Dolores Huerta, author Jeremy Heimans, "craftivist" Sarah Corbett, and designer and futurist Angela Oguntala.
Now Playing: Science for the People

#521 The Curious Life of Krill
Krill may be one of the most abundant forms of life on our planet... but it turns out we don't know that much about them. For a create that underpins a massive ocean ecosystem and lives in our oceans in massive numbers, they're surprisingly difficult to study. We sit down and shine some light on these underappreciated crustaceans with Stephen Nicol, Adjunct Professor at the University of Tasmania, Scientific Advisor to the Association of Responsible Krill Harvesting Companies, and author of the book "The Curious Life of Krill: A Conservation Story from the Bottom of the World".