Featured Research

from universities, journals, and other organizations

Study Finds Anthrax Toxins Also Harmful To Fruit Flies

Date:
February 2, 2006
Source:
University Of California, San Diego
Summary:
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. Their findings show that fruit flies can be used to study the link between the biochemical activities and physiological effects of anthrax toxins.

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

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. Their findings show that fruit flies can be used to study the link between the biochemical activities and physiological effects of anthrax toxins.

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.


Story Source:

The above story is based on materials provided by University Of California, San Diego. Note: Materials may be edited for content and length.


Cite This Page:

University Of California, San Diego. "Study Finds Anthrax Toxins Also Harmful To Fruit Flies." ScienceDaily. ScienceDaily, 2 February 2006. <www.sciencedaily.com/releases/2006/02/060202081446.htm>.
University Of California, San Diego. (2006, February 2). Study Finds Anthrax Toxins Also Harmful To Fruit Flies. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2006/02/060202081446.htm
University Of California, San Diego. "Study Finds Anthrax Toxins Also Harmful To Fruit Flies." ScienceDaily. www.sciencedaily.com/releases/2006/02/060202081446.htm (accessed October 21, 2014).

Share This



More Plants & Animals News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'Cadaver Dog' Sniffs out Human Remains

'Cadaver Dog' Sniffs out Human Remains

AP (Oct. 21, 2014) Where's a body buried? Buster's nose can often tell you. He's a cadaver dog, specially trained to find human remains and increasingly being used by law enforcement and accepted in courts. These dogs are helping solve even decades-old mysteries. (Oct. 21) Video provided by AP
Powered by NewsLook.com
White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Goliath Spider Will Give You Nightmares

Goliath Spider Will Give You Nightmares

Buzz60 (Oct. 20, 2014) An entomologist stumbled upon a South American Goliath Birdeater. With a name like that, you know it's a terrifying creepy crawler. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
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