Featured Research

from universities, journals, and other organizations

Drilling Holes Through Deadly Bacteria's Kevlar-like Hide

Date:
December 29, 2008
Source:
Rockefeller University
Summary:
To protect themselves from human defenses, disease-causing bacteria have evolved a cell wall made from a nearly impenetrable tangle of tightly woven strands. That's made it difficult for scientists to see what goes on inside these potentially deadly organisms. But that era is now over. Researchers have now figured out how to drill holes through the Kevlar-like hide of gram-positive bacteria without obliterating them, and in doing so, they've made it possible to study, from the inside out, most of the known bacteria on the planet.

Seeing through walls. An experiment shows that when dividing strep bacteria are stripped of their surface proteins (left), they begin to grow back in just minutes. One surface protein, protein M (green), anchors to the spot where sortase A (red) assembles. Before the bacteria finish dividing (right), sortase A has already begun to migrate to the new site of division.
Credit: Image courtesy of Rockefeller University

To protect themselves from human defenses, disease-causing bacteria have evolved a cell wall made from a nearly impenetrable tangle of tightly woven strands. That’s made it difficult for scientists to see what goes on inside these potentially deadly organisms. But that era is now over. Rockefeller University researchers have now figured out how to drill holes through the Kevlar-like hide of gram-positive bacteria without obliterating them, and in doing so, they’ve made it possible to study, from the inside out, most of the known bacteria on the planet.

Related Articles


The work, led by Vincent A. Fischetti, head of the Laboratory of Bacterial Pathogenesis and Immunology, provides, for the first time ever, a look inside the rapidly multiplying and highly contagious Streptococcus pyogenes, the culprit behind a myriad of diseases, including strep throat and rheumatic fever. At a time when organisms are increasingly acquiring “superbug” powers, Fischetti and his colleague Assaf Raz, a graduate student in the lab, have used the technique to look specifically at a well-known enzyme called sortase A and its distribution inside the cell. Common to all gram-positive bacteria, the enzyme functions by anchoring surface proteins to the cell wall, endowing the bacteria with their infectious properties.

“If you interfere with this process, you get naked bacteria and naked bacteria are unable to cause infection,” says Fischetti. “So the idea here is that the more we know how sortase functions inside the cell, the more strategies we’ll have to interfere with its activity stripping the bacteria of their pathogenic surface proteins.” Although the researchers worked with S. pyogenes, the approach could work on any gram-positive bacteria such as methicillin-resistant Staphylococcus aureus, or MRSA, which is increasingly becoming resistant to even our strongest antibiotics.

The technique relies on enzymes produced by viruses, called bacteriophages, which attack only bacteria. Unlike antibiotics, which take time to take effect, phage enzymes strike with blitzkrieg speed, preventing bacteria from mustering a defense. Usually, these enzymes destroy their target, leaving nothing but cellular debris behind. That’s because the pressure inside a bacterium is like a champagne bottle: Once it’s opened, it explodes. In their work, however, Fischetti and Raz figured out how to poke holes in S. pyogenes while keeping the bacteria intact. These holes provide an entryway for tags that fluoresce when they attach to molecules inside the altered bacteria, allowing scientists to visualize, from the inside out, what makes these single-celled powerhouses infectious.

In the past, if scientists wanted to study what goes on inside bacteria, they were largely limited to working with nonpathogenic types whose cell walls could be punctured with established methods. The new technique, however, allows them to directly study pathogenic bacteria and ask specific questions about them.

Fischetti and Raz were interested in whether the distribution of sortase A inside the cell affects the distribution of protein M, one of many surface proteins found on these bacteria. The researchers found that as the bacteria divide, the tagged sortase A assembles at a very specific location: the point of cell division where it anchors protein M. Interestingly, before the bacterium finishes dividing, sortase A starts to assemble at the new point of division — even before the recently formed bacteria starts dividing.

“So early assembly of sortase A at the division site allows bacteria to attach surface proteins to the cell wall as it is being built,” says Raz. “Whether or not sortase A is related to the division machinery we do not know yet, but we now have the tools to try and find out.”

Perhaps this migration is a way for bacteria to be ultra-organized. “Strep divide every 20 or 30 minutes under optimal conditions,” says Fischetti. “During that time, a lot of things are going on and the bug has to be extremely organized for all these things to happen very quickly. We now have the tools to start answering how these organisms carry out this feat. That’s one important thing that this work has accomplished. It could help us understand what makes this and other disease organisms function.”


Story Source:

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


Journal Reference:

  1. Raz et al. Sortase A localizes to distinct foci on the Streptococcus pyogenes membrane. Proceedings of the National Academy of Sciences, 2008; 105 (47): 18549 DOI: 10.1073/pnas.0808301105

Cite This Page:

Rockefeller University. "Drilling Holes Through Deadly Bacteria's Kevlar-like Hide." ScienceDaily. ScienceDaily, 29 December 2008. <www.sciencedaily.com/releases/2008/12/081227222727.htm>.
Rockefeller University. (2008, December 29). Drilling Holes Through Deadly Bacteria's Kevlar-like Hide. ScienceDaily. Retrieved March 27, 2015 from www.sciencedaily.com/releases/2008/12/081227222727.htm
Rockefeller University. "Drilling Holes Through Deadly Bacteria's Kevlar-like Hide." ScienceDaily. www.sciencedaily.com/releases/2008/12/081227222727.htm (accessed March 27, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Friday, March 27, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Jockey Motion Tracking Reveals Racing Prowess

Jockey Motion Tracking Reveals Racing Prowess

Reuters - Innovations Video Online (Mar. 26, 2015) Using motion tracking technology, researchers from the Royal Veterinary College (RVC) are trying to establish an optimum horse riding style to train junior jockeys, as well as enhance safety, health and well-being of both racehorses and jockeys. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Botswana Talks to End Illegal Wildlife Trade

Botswana Talks to End Illegal Wildlife Trade

AFP (Mar. 25, 2015) Experts are gathering in Botswana to try to end the illegal wildlife trade that is decimating populations of elephants, rhinos and other threatened species. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
Elephants Help Keep 18-Wheeler From Toppling Over

Elephants Help Keep 18-Wheeler From Toppling Over

Newsy (Mar. 25, 2015) The Natchitoches Parish Sheriff&apos;s Office discovered two elephants keeping a tractor-trailer that had gotten stuck in some mud upright on a highway. Video provided by Newsy
Powered by NewsLook.com
Baby 'pet' Orangutan Rescued from Chicken Cage Takes First Steps

Baby 'pet' Orangutan Rescued from Chicken Cage Takes First Steps

Reuters - Light News Video Online (Mar. 25, 2015) Buti, a baby orangutan who was left malnourished in a chicken cage before his rescue, takes his first steps after months of painful physical therapy. Mana Rabiee reports. Video provided by Reuters
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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