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.

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 July 28, 2014 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 July 28, 2014).

Share This




More Plants & Animals News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
Powered by NewsLook.com
Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
Powered by NewsLook.com
Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
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