Featured Research

from universities, journals, and other organizations

Differences In Gene Usage Dramatically Change Bacteria's 'Lifestyles'

Date:
December 15, 2004
Source:
Washington University School Of Medicine In St. Louis
Summary:
When and where a bacterium uses its DNA can be as important as what's in the DNA, according to researchers at Washington University School of Medicine in St. Louis. Scientists found significant differences in two bacterial organisms' use of a gene linked to processes that govern a form of antibiotic resistance. The distinction alters the bacteria's "lifestyles," or their ability to survive in different environments.

Nov. 30, 2004 — When and where a bacterium uses its DNA can be as important as what's in the DNA, according to researchers at Washington University School of Medicine in St. Louis.

Related Articles


Scientists found significant differences in two bacterial organisms' use of a gene linked to processes that govern a form of antibiotic resistance. The distinction alters the bacteria's "lifestyles," or their ability to survive in different environments.

Researchers say the finding shows that understanding such changes will likely help development of new treatments for disease-causing microorganisms.

"These differences in gene usage are harder to look for, but we're not going to understand these organisms fully unless we take into account this other dimension," says senior investigator Eduardo Groisman, Ph.D., professor of molecular microbiology and Howard Hughes Medical Institute investigator.

The study appears the week of Nov. 29 in the online edition of the Proceedings of the National Academy of Sciences and in print on Dec. 7.

One of the bacteria studied, Salmonella enterica, is a leading cause of food poisoning and illness related to animal husbandry. The other, Escherichia coli, can cause illness but more typically plays a beneficial role in the human digestive system.

The two are closely related genetically. Less than 20 percent of E. coli's genes are not found in Salmonella and just over 25 percent of Salmonella's genes lack counterparts in E. coli.

Groisman's research had previously focused on how differences in gene content made Salmonella a persistent source of illness. He identified several areas in the bacteria's DNA known as "pathogenicity islands" — clusters of genes unique to Salmonella that help it cause illness.

When complete gene maps for both bacteria became available in recent years, his interests expanded to understanding how the bacteria might use identical genes differently.

Salmonella and E. coli share the gene for an antibiotic resistance regulatory protein called PmrA. By controlling when other proteins are produced, PmrA can make the cell wall more resistant to damage from the antibiotic polymyxin B. The PmrA protein normally activates in response to high iron levels.

In a paper recently published in Genes and Development, Groisman's lab established that another protein, PmrD, also can activate PmrA in response to low magnesium levels.

In the new study, Groisman's lab discovered that E. coli has a different version of PmrD that is unable to turn on the PmrA protein in response to low magnesium.

"We're not really sure what the significance of low magnesium is, but there are some indications that it may be important to the bacteria's ability to survive in white blood cells or outside of the host in soil or water," Groisman says.

When scientists transplanted the Salmonella form of PmrD into E. coli, the bacteria gained the ability to resist polymyxin B in low magnesium environments.

Based on data still to be published, Groisman suspects that many other aspects of microbial lifestyle are affected by differences in regulation of identical genes.

He notes that the idea of different organisms making altered use of the same genes sprang from recent analyses of the human genome.

"Humans not only appear to have far fewer genes than expected, there also seem to be fewer genes that are unique to human DNA than anticipated," Groisman explains.

In addition to instructions for building proteins, DNA contains stretches of code that affect when genes are turned on and off. As life becomes more complex over the course of evolution, Groisman explains, these regulatory sections appear to take up larger portions of the DNA, allowing genes to be turned on and off in ways that are more intricately responsive to the environment and other factors.

Human DNA, Groisman speculates, may be heavily packed with the factors that allow a more complex, richer use of genes also found in other organisms.

###

Winfield MD, Groisman EA. Phenotypic differences between Salmonella and E. Coli resulting from the disparate regulation of homologous genes. Proceedings of the National Academy of Sciences, Dec. 7, 2004 101(49) 17162-17167.

Funding from the National Institutes of Health and the Howard Hughes Medical Institute.


Story Source:

The above story is based on materials provided by Washington University School Of Medicine In St. Louis. Note: Materials may be edited for content and length.


Cite This Page:

Washington University School Of Medicine In St. Louis. "Differences In Gene Usage Dramatically Change Bacteria's 'Lifestyles'." ScienceDaily. ScienceDaily, 15 December 2004. <www.sciencedaily.com/releases/2004/12/041206194710.htm>.
Washington University School Of Medicine In St. Louis. (2004, December 15). Differences In Gene Usage Dramatically Change Bacteria's 'Lifestyles'. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2004/12/041206194710.htm
Washington University School Of Medicine In St. Louis. "Differences In Gene Usage Dramatically Change Bacteria's 'Lifestyles'." ScienceDaily. www.sciencedaily.com/releases/2004/12/041206194710.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Stray Dog Follows Adventure Racing Team for 6-Day Endurance Race

Stray Dog Follows Adventure Racing Team for 6-Day Endurance Race

Buzz60 (Nov. 24, 2014) A Swedish Adventure racing team travels to try and win a world title, but comes home with something way better: a stray dog that joined the team for much of the grueling 430-mile race. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Deadly Japanese Pufferfish Discovered in Crimean Waters

Deadly Japanese Pufferfish Discovered in Crimean Waters

Reuters - Light News Video Online (Nov. 24, 2014) The capture of deadly Japanese pufferfish in the waters of Crimea is causing concern for fishermen and scientists alike. Sharon Reich reports. Video provided by Reuters
Powered by NewsLook.com
Terrifying Black Seadevil Fish Captured on First-of-Its Kind Video

Terrifying Black Seadevil Fish Captured on First-of-Its Kind Video

Buzz60 (Nov. 24, 2014) An aquarium captures a first-of-its kind video of a notoriously camera-shy fish that’s also not so camera-friendly. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Red Panda Cubs Explore the Bratislava Zoo

Red Panda Cubs Explore the Bratislava Zoo

AFP (Nov. 24, 2014) Four-month old Red Panda twins Pim and Pam still rely on their mother for breast milk at the Bratislava Zoo in Slovakia, but the precocious cubs have begun to branch out to solid foods, as well. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins