Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Differences in gene usage dramatically change bacteria’s ’lifestyles’


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. 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.

Michael Purdy | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht Make way for the mini flying machines
21.03.2018 | American Chemical Society

nachricht New 4-D printer could reshape the world we live in
21.03.2018 | American Chemical Society

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

TRAPPIST-1 planets provide clues to the nature of habitable worlds

21.03.2018 | Physics and Astronomy

The search for dark matter widens

21.03.2018 | Materials Sciences

Natural enemies reduce pesticide use

21.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>