Navigation Links
Bacteria control how infectious they become, study finds

The results of a new study suggest that bacteria that cause diseases like bubonic plague and serious gastric illness can turn the genes that make them infectious on or off.

Knowing how disease-causing bacteria, like Yersinia pestis and E. coli, do this may one day help scientists create drugs that control the expression of these genes, thereby making the bacteria harmless, said Vladimir Svetlov, a study co-author and a research associate in microbiology at Ohio State University. The findings appear in the April 13 issue of the journal Molecular Cell.

Gene expression ?the process of turning on, or activating, genes ?is controlled by proteins called transcription factors. Every type of bacteria known to humankind contains the transcription factor NusG, which controls nearly all of a bacterium's gene expression. Without it, a microorganism will die.

“We think that NusG regulates nearly every gene in every form of bacteria,?said Irina Artsimovitch, the study's lead author and an associate professor of microbiology at Ohio State . “Say a bacterium has 3,000 genes ?NusG would regulate 2,900 of them.?

But somewhere along the evolutionary path, NusG was copied and physically changed. The result was a specialized transcription factor called RfaH. Unlike NusG, RfaH controls only a small portion of gene expression. But it happens to turn on those genes that give bacteria like E. coli and Y. pestis their ability to infect.

The researchers say that this study likely marks the first successful attempt by a laboratory to determine the structure of RfaH.

They used special X-ray techniques to study and describe RfaH proteins that they had extracted from E. coli. They found that while about two-thirds of RfaH's structure closely resembles the structure of NusG, the remaining one-third looked dramatically different. It's this latter third that appears to be the portion of the protein responsible for controlling the genes that mak e E. coli infectious.

“In contrast to NusG, which is always active, RfaH is usually inactive, because the part of the protein that is needed to activate gene expression is typically masked,?Svetlov said.

It's only when RfaH finds the appropriate target sequence on a bacterium's DNA that this small portion of the protein is unmasked and can then turn on a select group of genes. These genes let disease-causing bacteria infect their host while at the same time protecting the bacteria from the host's immune defenses.

“E. coli seems to prevent RfaH from acting unless the microorganism absolutely needs it,?Artsimovitch said. That's because bacteria like E. coli are caught in a delicate balancing act. With too little RfaH, bacteria grow too slowly. But too much RfaH, and they will die.

While RfaH's control over gene expression is limited, it seems that its structure lets it control key sequences of the genome during transcription, the process of transferring genetic information inside a cell and one of the first steps of gene expression.

“Making RfaH work only at specific sites is, in a sense, a genius way to prevent it from interfering with NusG,?Artsimovitch said. “It seems that the only genes that RfaH can't regulate are those controlled by NusG.?

Bacteria can survive without RfaH, but not without NusG. Yet without RfaH, bacteria lose the ability to infect. In previous laboratory experiments, the researchers found that pathogens lacking RfaH grow at much slower rates.

“Cells usually don't die when RfaH use changes,?Svetlov said. “Rather, bacteria seem to manipulate the protein, to play around with it. Too much RfaH will kill a cell, while too little would prevent it from infecting any living being.

“We think that RfaH is responsible for more than making a microbe infectious,?he continued. “Actually seeing what happens at the molecular level will help us figure out what else this protein regul ates.?

Svetlov and Artsimovitch conducted the study with Georgy Belogurov, a postdoctoral research associate in microbiology at Ohio State, and with researchers from the University of Alabama at Birmingham, the Howard Hughes Medical Institute and the University of Texas Southwestern Medical Center in Dallas.


'"/>

Source:Ohio State University


Related biology news :

1. Bacteria collection sheds light on urinary tract infections
2. Solution to Pollution: New Bacteria Eats Toxic Waste
3. The Bacterias guide to survival
4. UF Researchers Map Bacterial Proteins That Cause Tooth Loss
5. Bacterial genome sheds light on synthesizing cancer-fighting compounds
6. Where Bacteria Get Their Genes
7. Bacteria feed on smelly breath (and feet)
8. New insight into autoimmune disease: Bacterial infections promote recognition of self-glycolipids
9. Bacteria use hosts immune response to their competitive advantage
10. Say what? Bacterial conversation stoppers
11. Bacteria are key to green plastics, drugs
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/26/2016)... LONDON , April 26, 2016 ... EdgeVerve Systems, a product subsidiary of Infosys (NYSE: ... a partnership to integrate the Onegini mobile security ... (Logo: http://photos.prnewswire.com/prnh/20151104/283829LOGO ) The ... enhanced security to access and transact across channels. ...
(Date:4/19/2016)... April 20, 2016 The new ... a compact web-based "all-in-one" system solution for all door ... reader or the door interface with integration authorization management ... control systems. The minimal dimensions of the access control ... the building installations offer considerable freedom of design with ...
(Date:4/15/2016)... , April 15, 2016 ... the,  "Global Gait Biometrics Market 2016-2020,"  report to ... http://photos.prnewswire.com/prnh/20160330/349511LOGO ) , ,The global gait biometrics ... of 13.98% during the period 2016-2020. ... angles, which can be used to compute factors ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... 23, 2016   Boston Biomedical , an ... designed to target cancer stemness pathways, announced that ... Orphan Drug Designation from the U.S. Food and ... cancer, including gastroesophageal junction (GEJ) cancer. Napabucasin is ... inhibit cancer stemness pathways by targeting STAT3, and ...
(Date:6/23/2016)... Prostate Cancer Foundation (PCF) is pleased to announce 24 new Young ... cancer. Members of the Class of 2016 were selected from a pool of ... More About the Class of 2016 PCF Young Investigators ... ... ...
(Date:6/23/2016)... ... June 23, 2016 , ... In a new case report published ... how a patient who developed lymphedema after being treated for breast cancer benefitted from ... the paradigm for dealing with this debilitating, frequent side effect of cancer treatment. ...
(Date:6/23/2016)... (PRWEB) , ... June 23, 2016 , ... ... is exhibiting at the Pennsylvania Convention Center and will showcase its product’s latest ... ClinCapture will also be presenting a scientific poster on Disrupting Clinical Trials in ...
Breaking Biology Technology: