Featured Research

from universities, journals, and other organizations

Bacteria use lethal cytotoxins to evade antibiotic treatment

Date:
November 18, 2013
Source:
Aarhus University
Summary:
Bacteria that cause infectious diseases produce a number of cytotoxins, and an international research team has now found the mechanism behind one of these toxins. The new results could make it possible in future to develop new treatment methods to impair the cytotoxic activity and thereby reduce the severity of infectious diseases.

The figure shows the bacterial 70S ribosome with the cleavage point for the cytotoxin VapC20 marked with red. To the right is transfer RNA, which is cleaved by a similar mechanism in the pathogenic organism Shigella flexneri. Behind this is an RNA gel showing the actual cleavage reaction in the ribosome.
Credit: Ditlev E. Brodersen

In spite of the fact that the first antibiotics were discovered almost a century ago, infectious diseases such as tuberculosis, encephalitis and meningitis are still serious diseases for humans in the twenty-first century. The World Health Organization (WHO) estimates that there are more than 8 million new cases of tuberculosis per year on a global scale, and that more than 300,000 of these are due to multidrug-resistant strains that are not only difficult to treat, but are also emerging rapidly in regions such as Eastern Europe.

Bacterial tolerance is not just due to resistance, but also to the formation of persistent cells that have gone into a dormant state where they are no longer sensitive to antibiotics. On the molecular level, this process is controlled by a number of advanced cytotoxins produced by the bacteria themselves in order to survive. In Mycobacterium tuberculosis -- the organism that causes tuberculosis -- there are no fewer than 88 such toxins, all of which presumably help the organism to survive.

In a new article in the journal Nature Communications, an international team of researchers with the participation of the Department of Molecular Biology and Genetics, Aarhus University, has revealed the mechanism behind one of these toxins -- VapC20. It turns out that when the toxin is activated, it destroys the tuberculosis bacteria's own protein 'factory' (the ribosome) by cleavage. The bacteria are thereby unable to produce proteins in the short term, and thus avoid the effect of antibiotics that also often attack the ribosome.

When treatment with antibiotics is completed, the pathogenic bacteria 'wake up' and are ready to synthesise new ribosomes. Surprisingly, it appears that the location in the ribosome that is cleaved by VapC20 is the same place that is destroyed by the strong cytotoxins α-sarcin andricin, which are found in plants such as castor beans and are twice as venomous as cobra snake poison.

Further analysis of the cleavage point in the ribosome also shows that the mechanism is presumably general for a number of the many toxins, and the new knowledge could therefore be used in future to develop new ways of treating pathogenic bacteria by impairing their ability to use such cytotoxins.


Story Source:

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


Journal Reference:

  1. Kristoffer S. Winther, Ditlev E. Brodersen, Alistair K. Brown, Kenn Gerdes. VapC20 of Mycobacterium tuberculosis cleaves the Sarcin–Ricin loop of 23S rRNA. Nature Communications, 2013; 4 DOI: 10.1038/ncomms3796

Cite This Page:

Aarhus University. "Bacteria use lethal cytotoxins to evade antibiotic treatment." ScienceDaily. ScienceDaily, 18 November 2013. <www.sciencedaily.com/releases/2013/11/131118091753.htm>.
Aarhus University. (2013, November 18). Bacteria use lethal cytotoxins to evade antibiotic treatment. ScienceDaily. Retrieved April 17, 2014 from www.sciencedaily.com/releases/2013/11/131118091753.htm
Aarhus University. "Bacteria use lethal cytotoxins to evade antibiotic treatment." ScienceDaily. www.sciencedaily.com/releases/2013/11/131118091753.htm (accessed April 17, 2014).

Share This



More Plants & Animals News

Thursday, April 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Great British Farmland Boom

The Great British Farmland Boom

Reuters - Business Video Online (Apr. 17, 2014) Britain's troubled Co-operative Group is preparing to cash in on nearly 18,000 acres of farmland in one of the biggest UK land sales in decades. As Ivor Bennett reports, the market timing couldn't be better, with farmland prices soaring over 270 percent in the last 10 years. Video provided by Reuters
Powered by NewsLook.com
Flamingo Frenzy Ahead of Zoo Construction

Flamingo Frenzy Ahead of Zoo Construction

AP (Apr. 17, 2014) With plenty of honking, flapping, and fluttering, more than three dozen Caribbean flamingos at Zoo Miami were rounded up today as the iconic exhibit was closed for renovations. (April 17) Video provided by AP
Powered by NewsLook.com
Change of Diet Helps Crocodile Business

Change of Diet Helps Crocodile Business

Reuters - Business Video Online (Apr. 16, 2014) Crocodile farming has been a challenge in Zimbabwe in recent years do the economic collapse and the financial crisis. But as Ciara Sutton reports one of Europe's biggest suppliers of skins to the luxury market has come up with an unusual survival strategy - vegetarian food. Video provided by Reuters
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. 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