Navigation Links
Fruit flies show how salmonella escapes immune defenses
Date:4/16/2008

Salmonella are wily and obnoxious bacterial invaders--escape artists capable of evading multiple immune responses and causing a harsh and debilitating intestinal infection.

Researchers have come closer to understanding how these bacteria manage to thwart two major categories of immune defenses at once and set up shop in a host organism. New results are reported in the April 2008 issue of the journal Cell Host & Microbe.

The Emory University research team used a transgenic fruit fly (drosophila) model to test a group of "effector proteins," also known as "virulence factors," secreted by invading organisms to usurp the host immune response for their own benefit.

They found that one of these proteins, named AvrA, not only shuts down the key immune signaling pathways JNK and NF-kB, but also turns off the fail safe system organisms have evolved to respond to irreversible threats. This ultimate immune defense, called apoptosis, eliminates invaders along with the infected cells through a system of programmed cell death.

In previous research, the scientists had showed that AvrA could suppress some aspects of immune system signaling in cell culture, but they wanted to study the protein in a whole animal system.

"Bacterial proteins are notoriously difficult to study," says Andrew Neish, MD, Emory professor of pathology and laboratory medicine and the study's lead scientist. "Using the drosophila system allowed us to express bacterial proteins in a controlled fashion. We were able to study salmonella infection and the associated proteins and signaling mechanisms in a whole animal, which gave us information we could not have gained from a cell culture dish."

To evaluate the effects of AvrA in natural salmonella infection in mammals, the scientists used a mouse model of salmonella infection and found that AvrA suppressed the same immune signaling pathways and apoptotic reaction as in the drosophila model. A mutant form of the salmonella lacking the AvrA protein caused an enhanced inflammatory immune response and markedly more cell death in the mouse intestine.

"Using drosophila genetics, we found a biochemical crossroad required for both immune and apoptotic pathways," says Neish. "The AvrA protein is able to key in on the exact site of the biochemical network and allow it to suppress both the inflammatory response and the apoptotic immune response at the same time. We suspect that other pathogens may target the same biochemical network to avoid elimination. These immune pathways in drosophila have been preserved across evolution and are remarkably similar to human immune pathways. This is such a powerful research system that any bacterial or viral genes would be amenable to study through this approach."


'/>"/>

Contact: Sarah Goodwin
sgoodwi@emory.edu
404-727-3366
Emory University
Source:Eurekalert

Related biology news :

1. CSHL scientists identify a mechanism that helps fruit flies lock-in memories
2. Like sweets? Youre more like a fruit fly than you think...
3. Crop scientists discover gene that controls fruit shape
4. Researchers create mathematical model of fruit fly eyes
5. The precise role of seminal proteins in sustaining post-mating responses in fruit flies
6. Kids eat more fruits, vegetables when schools offer salad bar
7. Tiny pest-eating insect fights fruit flies
8. Genome comparison of 12 fruit fly species
9. International team compares 12 fruit fly genomes
10. Ripe fruit preferred
11. Chemical in red wine, fruits and vegetables stops cancer, heart disease, depending on the dose
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/4/2017)... , April 4, 2017   EyeLock LLC ... announced that the United States Patent and Trademark Office ... broadly covers the linking of an iris image with ... transaction) and represents the company,s 45 th issued ... patent is very timely given the multi-modal biometric capabilities ...
(Date:3/30/2017)... The research team of The Hong Kong ... identification by adopting ground breaking 3D fingerprint minutiae recovery and matching ... and accuracy for use in identification, crime investigation, immigration control, security ... ... A research team led by ...
(Date:3/28/2017)... The report "Video Surveillance Market ... Storage Devices), Software (Video Analytics, VMS), and Service (VSaaS, ... to 2022", published by MarketsandMarkets, the market was valued ... to reach USD 75.64 Billion by 2022, at a ... year considered for the study is 2016 and the ...
Breaking Biology News(10 mins):
(Date:6/22/2017)... Frederick, MD (PRWEB) , ... June 22, 2017 ... ... software solutions provider, announced the release of Limfinity® version 6.5, a content-packed update ... Limfinity® framework continue to gain a larger and more diverse base of customers ...
(Date:6/20/2017)... ... June 20, 2017 , ... CTNext , Connecticut’s ... has formed a Higher Education Entrepreneurship Advisory Committee to implement the recommendations of ... other high-ranking representatives from 35 higher education institutions across the state over the ...
(Date:6/20/2017)... Fairfield, Iowa (PRWEB) , ... June 20, 2017 ... ... a chance to immediately determine the adulterants which pose the most likely threat ... 25 - 28 of this year. , IFT's annual food expo attracts ...
(Date:6/20/2017)... ... June 20, 2017 , ... National executive search firm, Slone ... assay development and biomarker expertise, as VP of Scientific Affairs at Cambridge Biomedical. ... bio-analytical assay development and sample testing services. The organization acts as a leading ...
Breaking Biology Technology: