Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bacterial Protein Shows Promise in Treating Intestinal Parasites

27.09.2006
Scientists at the University of California, San Diego and Yale University have discovered that a natural protein produced by Bacillus thuringiensis, a bacterium sprayed on crops by organic farmers to reduce insect damage, is highly effective at treating hookworm infections in laboratory animals.

Their discovery, detailed in this week’s early online edition of the Proceedings of the National Academy of Sciences, could pave the way for the development of more effective treatments for hookworm and other soil-transmitted nematode infections, which are a major global health problem in developing countries. Many of the nearly two billion people worldwide infected with these intestinal parasites are children, who are at particular risk for anemia, malnutrition and delayed growth.

The UCSD-Yale team found that a protein produced by the bacterium Bacillus thuringiensis, or Bt, given orally to laboratory hamsters infected with hookworms was as effective in eliminating the parasites, curing anemia and restoring weight gain in the hamsters as mebendazole, one of the drugs currently recommended to treat infections in humans. The scientists also discovered that this protein, called Cry5B, targets both developing, or larval, stages and adult parasites, as well as impairs the excretion of eggs by female worms.

Hookworms cause anemia by attaching to the intestine and feeding on their host’s blood and nutrients, causing anemia and weight loss. The researchers said in their paper that because this naturally-produced protein is safe to humans and other vertebrates and can be produced inexpensively in large quantities, it has the potential to substantially improve this global health problem.

“Our ability to control parasitic nematode infections with chemotherapy on a global scale is dependent on the availability of medicines that are safe, effective, and inexpensive to manufacture,” said Michael Cappello, one of two principal authors of the study and a professor of pediatrics and epidemiology & public health at Yale School of Medicine. “We believe that Bt crystal proteins not only meet, but exceed these essential criteria.”

The discovery is particularly relevant to global health, because of concerns about the potential emergence of resistance in human intestinal nematodes to currently available medicines.

“There are only a few new agents under development for the treatment of hookworm and other intestinal parasite infections," said Raffi Aroian, an associate professor of biology at UCSD and co-principal author of the study. " Crystal toxins are safe to humans, mammals and other vertebrates. And it might be possible to improve the efficacy of current treatments by giving a drug like mebendazole and Cry5B simultaneously.”

Other authors of the study are Richard Bungiro and Lisa Harrison of the Yale medical school and Larry Bischof, Joel Griffitts and Brad Barrows of UCSD.

Aroian and his UCSD colleagues discovered five years ago that the roundworm C. elegans and other nematodes are susceptible to the effects of Cry5B, then known primarily as an insecticide. The toxin forms tiny holes in the membranes of the cells of nematodes and insects. However, since the toxin can’t bind to the cells of mammals or other vertebrates, Cry proteins can’t hurt humans.

“Crystal proteins had been used for decades to kill insects by organic farmers who sprayed their crops with Bt,” said Aroian. “Until now, however, no one has used a purified Cry protein to treat a parasitic nematode.”

Aroian met Cappello, a pediatric infectious diseases specialist who studies hookworm, at a meeting of the Burroughs-Wellcome Fund and decided to collaborate on a project to see if crystal proteins could be effective against hookworm infections. Three years ago, Aroian and his colleagues purified Cry5B toxin and sent it to Cappello, who then tested the compound in a laboratory model of hookworm infection.

“It worked on the first day,” said Aroian. “Laboratory animals treated with Cry5B survived a lethal hookworm infection, and showed no side effects from the medication.”

Colleagues in Cappello’s lab then carried out additional experiments that demonstrated that Cry5B was comparable to mebendazole for treating hookworm infection in laboratory animals. Additional studies also determined which life cycle stages of the parasite were most susceptible to Cry5B and at what concentrations.

“These experiments confirmed that the mechanism of action of Cry5B in Ancylostoma hookworms appears to be identical to that for other nematodes, including C. elegans,” said Cappello. “This suggests that crystal proteins will likely have activity against a broad range of nematodes, and could be used to treat children who are often infected with multiple intestinal parasites. Studies are underway to fully define the spectrum of activity of Cry5B as part of its preclinical development as a human therapeutic.”

The study was supported by grants from the National Institutes of Health and the Burroughs Wellcome Fund.

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

Further reports about: Aroian Cappello Cry5B Stichwort 4451 anemia hookworm intestinal nematode parasite

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>