Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

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

30.11.2004


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.



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:
http://www.wustl.edu

More articles from Life Sciences:

nachricht New Test for Rare Immunodeficiency
23.08.2017 | Universität Basel

nachricht Repairing damaged hearts with self-healing heart cells
22.08.2017 | National University Health System

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>