Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Timing is everything: Bacterial attachment mimics the just-in-time industrial delivery model

01.12.2011
Understanding mechanism may aid in development of infection-fighting drugs

In the human world of manufacturing, many companies are now applying an on-demand, just-in-time strategy to conserve resources, reduce costs and promote production of goods precisely when and where they are most needed.


Caulobacter crescentus with the holdfast at top and the propelling flagellum at the opposite end.

A recent study from Indiana University Bloomington scientists reveals that bacteria have evolved a similar just-in-time strategy to constrain production of an extremely sticky cement to exactly the appropriate time and place, avoiding wasteful and problematic production of the material.

Indiana University biologists and two physicists at Brown University with IU connections have shown that certain bacteria wait until the last minute to synthesize the glue that allows them to attach permanently to surfaces. Binding efficiently to surfaces is extremely important to bacteria in the environment and for bacterial disease agents during the infection process.

The researchers found that bacteria -- including the freshwater bacterium Caulobacter crescentus and the agricultural pathogen Agrobacterium tumefaciens -- first connect to a surface with the cellular equivalents of propellers and cables and that this initial, reversible contact stimulates the synthesis of a sticky glue. This holdfast adhesin, which is composed of polysaccharide sugar molecules, is then released only at the site of surface contact to irreversibly attach the bacteria to host surfaces.

The study, "Surface contact stimulates the just-in-time deployment of bacterial adhesins," was published earlier this month in Molecular Microbiology . It describes how single bacterial cells use their flagella (the propellers) and pili (the cables) to facilitate the timely release of adhesive polysaccharides upon initial contact with other surfaces.

Microbiologists are generally interested in bacterial adhesion and formation of complex microbial communities called biofilms that can clog pipes, slow down ships and establish antibiotic-resistant infections. Efficient surface attachment strategies are advantageous to bacteria as they can increase nutrient access and resistance to environmental stress, including host defenses.

"For bacteria, surface attachment by single cells is the first step to important processes such as biofilm formation and host infection," said IU microbiologist Pamela Brown, one of the project's lead authors. "What we found is that the interaction of bacterial cells with a surface using their flagellum and pili stimulates the on-the-spot production of polysaccharide adhesins, propelling the transition from transient to permanent attachment."

The new findings also suggest that pathogenic bacteria may carefully time adhesin release to protect themselves from premature exposure to a host's immune system during infection.

The team used cutting-edge, high-resolution video microscopy to observe the single-cell attachment process in real time in the presence of a fluorescent stain that decorates the adhesive polysaccharide. They found that when Caulobacter cells are propelled to a surface by their rotating propeller-like single flagellum, the flagellar motor stopped immediately upon contact with the surface. Inhibition of flagellar rotation was quickly followed by the production of the holdfast polysaccharide adhesin, specifically from the cell pole containing the now inactive flagellum, and in contact with the surface.

"We knew that cable-like pili are present at the same pole of the cell as the flagellum, and we hypothesized that they played a key role in the process by interacting with the surface, thereby preventing the free rotation of the flagellum," said IU microbiologist Yves Brun, the project's principal investigator. Indeed, when the team made a mutation that abolished the pili, the cells became tethered to the surface by their flagellum, but its rotation continued and the cell eventually detached.

The team hypothesizes that just-in-time adhesin production may be a general phenomenon since they obtained similar results with two other bacterial species, Agrobacterium tumefaciens and Asticcacaulis biprosthecum.

"What is striking is that we found that this mechanism does more than stimulate binding to inert surfaces. It also operates when the plant pathogen Agrobacterium tumefaciens binds to host tissue," said IU microbiologist Clay Fuqua, who recently discovered the holdfast-type adhesin used by this bacterium to attach to plant tissue. "We think that the ability to rapidly deploy this permanent adhesin may be advantageous for swimming cells attempting to colonize a favorable environment."

Since pathogens such as Escherichia coli and Pseudomonas aeruginosa also attach by their pole prior to their transition from reversible to irreversible attachment, the authors hypothesize that this mechanism could also be at play during the infection process.

"Once we know more about the details of this mechanism, we may be able to design drugs that prevent this adhesin stimulation, therefore reducing the efficiency of infections," Brown said.

Research from Brun's laboratory and that of Brown University physicist Jay Tang on bacterial glues published in 2006 (IU news release here) received international attention after they showed that the holdfast "glue" released by the tiny Caulobacter cells was the strongest in nature with a pulling force of 1 micronewton, equivalent to holding three or four cars with glue spread on the surface of a quarter.

"For such a strong adhesive, it may be important to avoid producing it too early because it might lose its efficiency, or it might get the cells irreversibly bound to the wrong surface. The analogy to the human world is amazing: You don't apply glue hours before you want to use it because it cures and hardens," Brun said.

Timing is everything, and with just-in-time adhesive production, cells have a better chance for efficient surface interaction and colonization because the two main factors in reducing adhesion -- curing and coating of glue with small particles -- are inhibitory mechanisms that require time to decrease adhesiveness. The on-the-spot production of adhesins circumvents this problem.

Funding for this research was provided by the National Institutes of Health, the Indiana University Faculty Research Support Program and the Indiana METACyt Initiative of IU. Brun is the Clyde Culbertson Professor of Biology in the IU College of Arts and Sciences' Department of Biology; Brown is a postdoctoral research fellow in the Brun lab; Fuqua is a professor of biology and associate chair for research; and Tang, an associate professor of physics and engineering at Brown University, was an assistant professor of physics at IU from 1999 to 2002. Other contributors to the study include co-lead author Guanglai Li, a research assistant professor of physics at Brown University, who was a postdoctoral fellow in physics at IU from 2002 to 2003; Jing Xu, a microbiology graduate student in the Fuqua lab; and Ellen Quardokus, a research associate in the Brun lab.

For more information please contact Steve Chaplin, University Communications, at 812-856-1896 or stjchap@iu.edu.

"Surface contact stimulates the just-in-time deployment of bacterial adhesins," by Guanglai Li; Pamela J. B. Brown; Jay X. Tang; Jing Xu; Ellen M. Quardokus; Clay Fuqua; Yves V. Brun; Molecular Microbiology, published Nov. 22, 2011; DOI: 10.1111/j.1365-2958.2011.07909.x.

Steve Chaplin | EurekAlert!
Further information:
http://www.iu.edu

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

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...

Im Focus: Studying fundamental particles in materials

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...

Im Focus: Designing Architecture with Solar Building Envelopes

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...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>