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:4/28/2016)... First quarter 2016:   , Revenues amounted ... quarter of 2015 The gross margin was 49% (27) ... the operating margin was 40% (-13) Earnings per share ... operations was SEK 249.9 M (21.2) , Outlook   ... M. The operating margin for 2016 is estimated to ...
(Date:4/15/2016)... -- Research and Markets has announced the ...  report to their offering.  ,      ... gait biometrics market is expected to grow at ... Gait analysis generates multiple variables such ... compute factors that are not or cannot be ...
(Date:3/29/2016)... 2016 LegacyXChange, Inc. (OTC: ... SelectaDNA/CSI Protect are pleased to announce our successful effort ... variety of writing instruments, ensuring athletes signatures against counterfeiting ... from athletes on LegacyXChange will be assured of ongoing ... Bill Bollander , CEO states, "By ...
Breaking Biology News(10 mins):
(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)... ... June 23, 2016 , ... Regulatory Compliance Associates® Inc. (RCA), ... free webinar on Performing Quality Investigations: Getting to Root Cause. ... no charge. , Incomplete investigations are still a major concern to the Regulatory ...
(Date:6/22/2016)... 2016 Research and Markets has announced the ... to their offering. The ... $29.3 billion in 2013. The market is expected to grow at ... to 2020, increasing from $50.6 billion in 2015 to $96.6 billion ... the forecast period (2015 to 2020) are discussed. As well, new ...
(Date:6/22/2016)... ... June 21, 2016 , ... New light-based technologies that facilitate a “look inside” ... to enable both compact, wearable devices for point-of-care diagnostics as well as powerful new ... Recent work and visionary future directions are detailed in a new open-access article by ...
Breaking Biology Technology: