Featured Research

from universities, journals, and other organizations

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

Date:
December 7, 2011
Source:
Indiana University
Summary:
Biologists and physicists have shown that certain bacteria wait until the last minute to synthesize the glue that allows them to attach permanently to surfaces.

Caulobacter crescentus with the holdfast at top and the propelling flagellum at the opposite end.
Credit: Image courtesy of Indiana University

n 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. 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 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.


Story Source:

The above story is based on materials provided by Indiana University. Note: Materials may be edited for content and length.


Journal Reference:

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

Cite This Page:

Indiana University. "Timing is everything: Bacterial attachment mimics just-in-time industrial model." ScienceDaily. ScienceDaily, 7 December 2011. <www.sciencedaily.com/releases/2011/11/111130142226.htm>.
Indiana University. (2011, December 7). Timing is everything: Bacterial attachment mimics just-in-time industrial model. ScienceDaily. Retrieved September 21, 2014 from www.sciencedaily.com/releases/2011/11/111130142226.htm
Indiana University. "Timing is everything: Bacterial attachment mimics just-in-time industrial model." ScienceDaily. www.sciencedaily.com/releases/2011/11/111130142226.htm (accessed September 21, 2014).

Share This



More Plants & Animals News

Sunday, September 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: San Diego Zoo Welcomes Cheetah Cubs

Raw: San Diego Zoo Welcomes Cheetah Cubs

AP (Sep. 20, 2014) The San Diego Zoo has welcomed two Cheetah cubs to its Safari Park. The nearly three-week-old female cubs are being hand fed and are receiving around the clock care. (Sept. 20) Video provided by AP
Powered by NewsLook.com
Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins