Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study Finds Anthrax Toxins Also Harmful To Fruit Flies

31.01.2006


Deadly and damaging toxins that allow anthrax to cause disease and death in mammals have similar toxic effects in fruit flies, according to a study conducted by biologists at the University of California, San Diego.


Photo shows effect of anthrax lethal factor toxin in dorsal cells of developing fruit fly larvae. Credit: Annabel Guichard, UCSD



Their findings, which appear this week in an early online edition of the journal Proceedings of the National Academy of Sciences, show that fruit flies can be used to study the link between the biochemical activities and physiological effects of anthrax toxins.

Learning how these toxins attack developing and adult tissues is important because it can help scientists understand how they function at the molecular level and may lead to new therapeutic strategies for neutralizing their effects in humans.


Annabel Guichard, a biologist at UCSD and lead author of the study, tracked the ways that two active anthrax toxins, known as lethal factor, or LF, and edema factor, EF, cause cellular damage and death in the fruit fly Drosophila melanogaster. These toxins are required for the anthrax bacterium Bacillus anthracis to evade the host immune system and cause disease.

Using a combination of biochemical, genetic and cell biological approaches, the biologists tested whether or not the anthrax toxins were active in living Drosophila and, if so, whether they acted in the same way as they do in humans. The biologists found that anthrax toxins do alter the same signaling pathways used for cell communication in fruit flies and humans.

“Drosophila is an excellent tool to understand the effect of a toxin on its host and to determine the molecular mechanism underlying its toxicity, because the fly system is already so well characterized,” Guichard said. “We knew how anthrax toxins acted on human cells, but this study is the first to show that these toxins are active in fruit flies, suggesting that this fast breeding laboratory animal could also be used to determine the function of a variety of bacterial and viral pathogenic factors.”

Anthrax bacterium secretes three toxins, including LF and EF, and is only known to infect mammals. Because fruit flies lack components required for toxin entry into cells, they cannot actually contract the anthrax disease. However, the study finds that fruit flies can be used to test the effects of a single virulence factor, such as the LF or EF toxins, on signaling pathways shared by flies and humans.

Guichard and her co-authors applied lethal factor toxin to fruit fly embryos and larvae and observed that a component of the expected signaling pathway was inactivated, disrupting the whole molecular system and leading to death. When applied in a more limited fashion, LF interfered with the formation of sutures in the epidermis, resulting in a hole or cleft in thoracic regions of embryos and adults. This developmental process disrupted by LF treatment is similar mechanistically to wound healing, which is mediated by the same signaling pathway in humans.

The EF toxin is also lethal when applied to fly larvae and can cause severe malformation in the wings of adult fruit flies—an effect that can also be understood as an interruption of another unrelated signaling process common to flies and humans.

“We asked the simple question of whether anthrax toxins affecting mammals could act on the fly counterparts of proteins affected in humans, and the answer is yes,” said Ethan Bier, a professor of biology at UCSD who was the senior author of the study. “What this means is that similar types of analyses might identify yet unknown proteins shared by flies and humans that can be acted on by anthrax toxins. More generally, this study suggests that flies can be used as a rapid whole organism system to determine the function of a variety of bacterial and viral pathogens of unknown function. One could then test hypotheses obtained from these studies with flies in mammalian organisms such as mice.”

The biologists also anticipate that toxins such as the anthrax lethal factor toxin that have multiple host target proteins may be used to simultaneously reduce or eliminate the activities of several related proteins that perform overlapping functions in other diseases or biological processes. Such experimental tools could accelerate progress in various areas of biomedical research.

Guichard first conceived this study in 2002, to apply her experience in molecular genetic studies to research that had medical application. At that time, after the spate of anthrax-laced letters in 2001, anthrax became a charged topic in the research community and the general public.

“Anthrax is still a hot subject because of its possible use as a weapon of bioterrorism and remains a health threat in third world countries,” Guichard said. “Anthrax infections can be cured by antibiotics when detected early. But after a certain point, the toxins released in the bloodstream can kill the patient even after antibiotic treatment. The more we understand about how the toxins function, the better we’ll be able to design effective co-operative or “adjunctive” therapies.”

Other contributors to this study were Michael Karin in the department of pharmacology at UCSD’s School of Medicine, Jin Mo Park, now at Harvard Medical School and Beatriz Cruz-Moreno at UCSD. The study was supported by grants from the National Institutes of Health.

Media Contact: Kim McDonald (858) 534-7572.

Comments: Annabel Guichard (858) 534-0442, or Ethan Bier (858) 534-8792.

Kim McDonald | EurekAlert!
Further information:
http://www.ucsd.edu

More articles from Life Sciences:

nachricht Modern genetic sequencing tools give clearer picture of how corals are related
17.08.2017 | University of Washington

nachricht The irresistible fragrance of dying vinegar flies
16.08.2017 | Max-Planck-Institut für chemische Ökologie

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

Gold shines through properties of nano biosensors

17.08.2017 | Physics and Astronomy

Greenland ice flow likely to speed up: New data assert glaciers move over sediment, which gets more slippery as it gets wetter

17.08.2017 | Earth Sciences

Mars 2020 mission to use smart methods to seek signs of past life

17.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>