Navigation Links
CRISPR system can promote antibiotic resistance
Date:7/14/2014

CRISPR, a system of genes that bacteria use to fend off viruses, is involved in promoting antibiotic resistance in Francisella novicida, a close relative of the bacterium that causes tularemia. The finding contrasts with previous observations in other bacteria that the CRISPR system hinders the spread of antibiotic resistance genes.

The results are scheduled for publication in PNAS Early Edition.

The CRISPR system has attracted considerable attention for its potential uses in genetic engineering and biotechnology, but its roles in bacterial gene regulation are still surprising scientists. It was discovered by dairy industry researchers seeking to prevent phages, viruses that infect bacteria, from ruining the cultures used to make cheese and yogurt.

Bacteria incorporate small bits of DNA from phages into their CRISPR region and use that information to fight off the phages by chewing up their DNA. Cas9, an essential part of the CRISPR system, is a DNA-chewing enzyme that has been customized for use in biotechnology.

F. novicida infects rodents and only rarely infects humans, but it is a model for studying the more dangerous F. tularensis, a potential biological weapon. The bacteria infect and replicate inside macrophages, a type of immune cell.

Researchers at the Division of Infectious Diseases of the Emory University School of Medicine and the Emory Vaccine Center were surprised to find that when the gene encoding Cas9 is mutated in F. novicida bacteria, they become more vulnerable to polymyxin B as well as standard antibiotic treatments such as streptomycin and kanamycin. They were able to trace the effects of the mutation back to a defect in "envelope integrity." Cas9 regulates production of a lipoprotein, which appears to alter membrane permeability.

"The mutant bacteria are more permeable to certain chemicals from the outside," says David Weiss, PhD, assistant professor of medicine (infectious diseases) at Emory University School of Medicine and Yerkes National Primate Research Center. "That increased permeability also seems to make them more likely to set off alarms when they are infecting mammalian cells."

Graduate student Timothy Sampson, working with Weiss, found that Cas9 mutant bacteria may be more likely to leak bits of their DNA, a trigger for immune cells to get excited. This is a large reason why Cas9 is necessary for F. novicida to evade the mammalian immune system, a finding published in a 2013 Nature paper.

The regulatory role for Cas9 does not appear to be restricted to F. novicida; Weiss's team found that a Cas9 mutant in Campylobacter jejuni, a bacterium that is a common cause of human gastroenteritis, also has increased permeability and impaired antibiotic resistance.

The findings add to recent discoveries where Cas9 has been found to be involved in virulence the ability to cause disease in a living animal or human -- in various pathogenic bacteria such as Campylobacter and Neisseria meningitides.


'/>"/>

Contact: Quinn Eastman
qeastma@emory.edu
404-727-7829
Emory Health Sciences
Source:Eurekalert

Related biology news :

1. Shortening guide RNA markedly improves specificity of CRISPR-Cas nucleases
2. Disease knowledge may advance faster with CRISPR gene probing tool
3. Electronic Access Control Systems Market is Expected to Reach USD 31.2 Billion Globally in 2019: Transparency Market Research
4. Mouse study: Natural birth may strengthen the immune system
5. Whales as ecosystem engineers
6. A single gene separates aggressive and non-aggressive lymphatic system cancer
7. Biology of infection: A bacterial ballistic system
8. Mountain ecosystems scientists to convene at University of Nevada, Reno
9. Gum disease bacteria selectively disarm immune system, Penn study finds
10. Engineers design systems to help children with special needs
11. EcoHealth 2014 connects researchers addressing impacts of global change on health and ecosystems
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/2/2016)... 2, 2016   The Weather Company , an IBM ... an industry-first capability in which consumers will be able to ... ask questions via voice or text and receive relevant information ... Marketers have long sought an advertising solution that ... be personal, relevant and valuable; and can scale across millions ...
(Date:5/20/2016)... May 20, 2016  VoiceIt is excited to ... VoicePass. By working together, VoiceIt and ... VoiceIt and VoicePass take slightly different approaches to ... both security and usability. ... this new partnership. "This marketing and ...
(Date:5/3/2016)... VILNIUS, Lithuania , May 3, 2016 /PRNewswire/ ... today released the MegaMatcher Automated Biometric Identification ... deployment of large-scale multi-biometric projects. MegaMatcher ABIS can ... and accuracy using any combination of fingerprint, face ... of MegaMatcher SDK and MegaMatcher ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... TORONTO , June 23, 2016 /PRNewswire/ - ... Ontario biotechnology company, Propellon ... the development and commercialization of a portfolio of ... cancers. Epigenetic targets such as WDR5 represent an ... contribute significantly in precision medicine for cancer patients. ...
(Date:6/23/2016)...  The Biodesign Challenge (BDC), a university competition that ... living systems and biotechnology, announced its winning teams at ... New York City . The teams, ... at MoMA,s Celeste Bartos Theater during the daylong summit. ... curator of architecture and design, and Suzanne Lee ...
(Date:6/23/2016)... 23, 2016 Apellis Pharmaceuticals, Inc. today ... trials of its complement C3 inhibitor, APL-2. The ... ascending dose studies designed to assess the safety, ... injection in healthy adult volunteers. Forty ... a single dose (ranging from 45 to 1,440mg) ...
(Date:6/23/2016)... Pleasant Prairie, WI (PRWEB) , ... June 23, ... ... sciences consultancy focused on quality, regulatory and technical consulting, provides a free ... webinar is presented on July 13, 2016 at 12pm CT at no charge. ...
Breaking Biology Technology: