Navigation Links
Symbiotic microbes induce profound genetic changes in their hosts
Date:7/28/2008

MADISON Though bacteria are everywhere from the air we breathe and the food we eat to our guts and skin the vast majority are innocuous or even beneficial, and only a handful pose any threat to us. What distinguishes a welcome microbial guest from an unwanted intruder?

Research from the University of Wisconsin-Madison suggests the answer lies not with the bacteria, but with the host.

A study appearing online this week in the Proceedings of the National Academy of Sciences may help reveal what sets a platonic relationship apart from a pathogenic one. In the paper, researchers from the UW-Madison School of Medicine and Public Health and the University of Iowa identify a slew of microbe-induced genetic changes in a tiny squid, including a set of evolutionarily conserved genes that may hold the secrets to developing a mutually beneficial relationship.

"Interactions of animals with their microbiota have a profound impact on their gene expression, and to create a stable association with a microorganism requires a lot of conversation between the microbe and the host," says UW-Madison medical microbiologist Margaret McFall-Ngai, senior author of the new study.

Many studies have focused on the bacterial side of that conversation. But aside from a few "professional pathogens," like the bubonic plague-causing Yersinia pestis, most bacteria are not inherently good or bad, McFall-Ngai says. Instead, bacterial effects are highly context-dependent: She reported in 2004 that a common bacterial "toxin" which causes tissue damage under some circumstances also plays a critical role in host tissue development.

She now suggests that the outcome may rely on how the host itself responds to the bacterium. Problems most often arise when a normal balance is disrupted, she says. "A lot of these pathogens are just at the wrong place at the wrong time."

To listen into the animal-microbe conversation, McFall-Ngai takes advantage of a relatively simple host-bacterium relationship: the Hawaiian bobtail squid, a colorful critter less than two inches long that nurtures a single type of light-producing bacteria, called Vibrio fischeri. The bacteria take up residence in a specialized pouch on the squid's belly and produce light that the squid uses as anti-predator camouflage. In return, the bacteria receive easy access to nutrients from the squid.

In the new study, a team led by former UW-Madison graduate student Carlene Chun dissected the genetics of the squid host response, including a comparison with mutant bacteria unable to successfully colonize their host. They identified hundreds of genes affected by the establishment of a stable bacterial partnership, including some known to play a role in human responses to bacteria.

The involvement of several genes typically associated with responses to bacterial infection, such as members of common immune signaling pathways, suggests we may need to rethink our understanding of the main purpose of the immune system, McFall-Ngai says.

"We have thousands of bacteria that live with us, and yet there are only around 100 bacterial pathogens," she says. Given the numbers, "it seems like these pathways and these molecules are likely to be 'symbiosis' pathways more than 'anti-pathogen.'"

Her team also highlighted several genes corresponding to those previously implicated in establishing symbiotic relationships with gut bacteria in fish and mice, suggesting that the animal-bacteria conversation may be basically the same across evolution.

"All animals and plants evolved in the background of the presence of huge numbers of environmental bacteria These genes might be considered the core conserved responses of animals to interactions with bacteria" along tissue surfaces like intestine walls and skin, McFall-Ngai says. "The language is ancient and highly conserved."


'/>"/>

Contact: Margaret McFall-Ngai
mjmcfallngai@wisc.edu
608-262-2393
University of Wisconsin-Madison
Source:Eurekalert

Related biology technology :

1. New Phase III Data Demonstrate Oxycodone / Naloxone Combination Tablet Reduces Opioid-Induced Bowel Dysfunction in Patients With Chronic Severe Pain
2. Entry of Biogenerics and Decreasing Use of Amgens Epogen and Johnson & Johnsons Procrit Will Cause a $2.8 Billion Decline in the Drug Market for Chemotherapy-Induced Anemia by 2016
3. ProMetic reports continued positive data in PBI-1402 phase II trial in chemotherapy-induced anemia
4. New Therapy by Merck is Positioned to Earn Gold-Standard Status by 2011 in the Treatment of Chemotherapy-Induced Nausea and Vomiting
5. Oral PBI-1402 Demonstrates Significant Activity in Chemotherapy-Induced Anemia Phase II Clinical Trial
6. Wyeth and Progenics Receive Positive Opinion From European Committee for RELISTOR for the Treatment of Opioid-Induced Constipation in Advanced-Illness Patients
7. Two Year Study Confirms SUPPRELIN(R) LA Implant Maintains Profound Suppression of Hormones in Children With Premature Onset Puberty
8. Digital Unions RT1(TM) Software Creates Telegenetics Network for Region 3 Genetics Collaborative
9. Response Genetics Reports Second Quarter 2007 Financial Results
10. ZymoGenetics Will Hold Conference Call Today at 5:00 p.m. Eastern Time to Provide Update on rThrombin
11. Clinical Data Acquires Epidauros Biotechnologie AG, Significantly Enhancing Proprietary Genetic Biomarker Portfolio
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/5/2016)... Australian-US drug discovery and development company, Novogen Limited ... a new Chairman, Mr John O,Connor , and new ... James Garner , has also been formally appointed ... CEO, Mr Iain Ross , will resume his role ... James Garner , has also been formally appointed to the ...
(Date:2/4/2016)... ... , ... Shimadzu Scientific Instruments will showcase several new products, ... sessions, and present on the analysis of mycotoxins and medical cannabis at the ... at the Georgia World Congress Center in Atlanta, Georgia. , Attendees should ...
(Date:2/4/2016)... MENLO PARK, Calif. , Feb. 4, 2016 /PRNewswire/ ... "Company"), a biopharmaceutical company focused on the development and commercialization ... at the 18 th Annual BIO CEO & ... a.m. EST in New York, NY . ... will provide an update on the ongoing clinical trial of ...
(Date:2/4/2016)... Sinovac Biotech Ltd. ("Sinovac" or the "Company") (NASDAQ: ... China , today announced that the ... February 4, 2016 a preliminary non-binding proposal letter, dated ... V-Ming ( Shanghai ) Investment Holdings Co., ... Shenzhen ) Fund Management Co., Ltd., Beijing ...
Breaking Biology Technology:
(Date:2/2/2016)... Feb. 2, 2016  BioMEMS devices deployed ... focused on medical screening and diagnostic applications, ... Wearable devices that facilitate and assure continuous ... movement are being bolstered through new opportunities ... signal acquisition coupled with wireless connectivity and ...
(Date:2/2/2016)... 2, 2016 Technology Enhancements Accelerate Growth of X-ray ... the digital and computed radiography markets in ... Indonesia (TIM). It provides an ... as well as regional market drivers and restraints. The ... penetration and market attractiveness, both for digital and computed ...
(Date:2/1/2016)... , February 1, 2016 Rising ... to drive global touchfree intuitive gesture control market ... Rising sales of consumer electronics coupled with new ... market size through 2020   ... coupled with new technological advancements to drive global touchfree ...
Breaking Biology News(10 mins):