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

More articles from Life Sciences:

nachricht Discovery of a Key Regulatory Gene in Cardiac Valve Formation
24.05.2017 | Universität Basel

nachricht Carcinogenic soot particles from GDI engines
24.05.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>