ScienceDaily (Mar. 19, 2010) — Biozentrum researchers have now discovered that Escherichia coli bacteria harness a sophisticated chemosensory and signal transduction machinery that allows them to accurately control motor rotation, thereby adjusting their swimming velocity in response to changing environments. The research results that were published online in Cell on March 18, 2010, may foster the development of novel strategies to fight persistent infections.
Trajectories of swimming E.Coli bacteria. (Credit: Image courtesy of University of Biozentrum Basel)
The research team from Switzerland and Germany, led by Alex Böhm and Urs Jenal from the Biozentrum has now discovered that E. coli, and probably many other bacteria can actively regulate their swimming velocity.
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Cell
Second Messenger-Mediated Adjustment of Bacterial Swimming Velocity
Alex Boehm1, , , Matthias Kaiser1, Hui Li2, Christian Spangler3, Christoph Alexander Kasper1, Martin Ackermann4, 5, Volkhard Kaever3, Victor Sourjik2, Volker Roth6 and Urs Jenal1
1 Biozentrum, University of Basel, CH-4056 Basel, Switzerland
2 Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, D-69120 Heidelberg, Germany
3 Institute of Pharmacology, Hannover Medical School, 30625 Hannover, Germany
4 Department of Environmental Sciences, ETH Zurich, CH-8092 Zürich, Switzerland
5 Department of Environmental Microbiology, EAWAG, CH-8092 Zürich, Switzerland
6 Department of Computer Science, University of Basel, CH-4056 Basel, Switzerland
Alex Boehm1, , , Matthias Kaiser1, Hui Li2, Christian Spangler3, Christoph Alexander Kasper1, Martin Ackermann4, 5, Volkhard Kaever3, Victor Sourjik2, Volker Roth6 and Urs Jenal1
1 Biozentrum, University of Basel, CH-4056 Basel, Switzerland
2 Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, D-69120 Heidelberg, Germany
3 Institute of Pharmacology, Hannover Medical School, 30625 Hannover, Germany
4 Department of Environmental Sciences, ETH Zurich, CH-8092 Zürich, Switzerland
5 Department of Environmental Microbiology, EAWAG, CH-8092 Zürich, Switzerland
6 Department of Computer Science, University of Basel, CH-4056 Basel, Switzerland
Received 3 November 2009;
revised 9 December 2009;
accepted 8 January 2010.
Published online: March 18, 2010.
Available online 18 March 2010.
Summary
Bacteria swim by means of rotating flagella that are powered by ion influx through membrane-spanning motor complexes. Escherichia coli and related species harness a chemosensory and signal transduction machinery that governs the direction of flagellar rotation and allows them to navigate in chemical gradients. Here, we show that Escherichia coli can also fine-tune its swimming speed with the help of a molecular brake (YcgR) that, upon binding of the nucleotide second messenger cyclic di-GMP, interacts with the motor protein MotA to curb flagellar motor output. Swimming velocity is controlled by the synergistic action of at least five signaling proteins that adjust the cellular concentration of cyclic di-GMP. Activation of this network and the resulting deceleration coincide with nutrient depletion and might represent an adaptation to starvation. These experiments demonstrate that bacteria can modulate flagellar motor output and thus swimming velocity in response to environmental cues.
Graphical Abstract
Graphical Abstract
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Highlights
► Concentration of second messenger cyclic di-GMP sets bacterial swimming velocity ► Upon cyclic di-GMP binding, YcgR interacts with the flagellar motor protein MotA ► YcgR binding to MotA acts to curb motor output in a brake-like fashion ► Pathway activation and resulting deceleration coincide with nutrient depletion
Author Keywords: CELLBIO; SIGNALING; MICROBIO
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NOTA DESTE BLOGGER:
Fui, nem sei por que, pensando que quanto mais os cientistas pesquisam o flagelo bacteriano, o mascote da teoria do Design Inteligente, eles em vez de falsificarem a nossa hipótese, mais ela é corroborada no contexto de justificação teórica - o flagelo bacteriano não pode ser explicado por processos gradualistas darwinianos ao longo de longas eras: é resultado de Design Inteligente!
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NOTA DESTE BLOGGER:
Fui, nem sei por que, pensando que quanto mais os cientistas pesquisam o flagelo bacteriano, o mascote da teoria do Design Inteligente, eles em vez de falsificarem a nossa hipótese, mais ela é corroborada no contexto de justificação teórica - o flagelo bacteriano não pode ser explicado por processos gradualistas darwinianos ao longo de longas eras: é resultado de Design Inteligente!
