Navigation Links
Bacterial protein shows promise in treating intestinal parasites

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 an d 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 inf ection.

"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."
'"/>

Source:University of California - San Diego


Related biology news :

1. UF Researchers Map Bacterial Proteins That Cause Tooth Loss
2. Bacterial genome sheds light on synthesizing cancer-fighting compounds
3. New insight into autoimmune disease: Bacterial infections promote recognition of self-glycolipids
4. Say what? Bacterial conversation stoppers
5. Bacterial protein mimics host to cripple defenses
6. Bacterial switch gene regulates how oceans emit sulfur into atmosphere
7. Bacterial response to oxidation studied as toxin barometer
8. Bacterial walls come tumbling down
9. New, automated tool successfully classifies and relates proteins in unprecedented way
10. New binding target for oncogenic viral protein
11. Controversial drug shown to act on brain protein to cut alcohol use

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:2/9/2016)... Aware, Inc. (NASDAQ: AWRE ), a leading supplier of biometrics ... and year ended December 31, 2015.  --> ... was $6.9 million, an increase of 61% compared to $4.3 million ... quarter of 2015 was $2.6 million compared to $0.2 million in ... --> Higher revenue and operating income in the fourth ...
(Date:2/5/2016)... Feb. 5, 2016 ... the "Global Facial Recognition Market 2016-2020" ... http://www.researchandmarkets.com/research/5kvw8m/global_facial ) has announced the addition ... 2016-2020" report to their offering. ... ) has announced the addition of the ...
(Date:2/3/2016)... India , February 3, 2016 ... the new market research report "Automated Fingerprint Identification System ... Search, Latent Search), Application (Banking & Finance, Government, Healthcare, ... published by MarketsandMarkets, the market is expected to be ... CAGR of 21.0% between 2015 and 2020. The transformation ...
Breaking Biology News(10 mins):
(Date:2/11/2016)... 2016  Vermillion, Inc. (NASDAQ: VRML ), a ... the formation of the Steering Committee for its Pelvic ... --> Pelvic masses can present physicians and healthcare ... pregnancy is ruled out, pelvic masses may include cancers ... benign ovarian tumors and gastrointestinal and urinary tract masses. ...
(Date:2/11/2016)... , Germany and ... QGEN ; Frankfurt Prime Standard: QIA) today ... Targeted RNA Panels for gene expression profiling, expanding QIAGEN,s ... (NGS). The panels enable researchers to select from over ... changes and discover interactions between genes, cellular phenotypes and ...
(Date:2/11/2016)... , Feb. 11, 2016  Bioethics International, a not-for-profit organization ... researched, developed, marketed and made accessible to patients around the ... had named the publication of the Good Pharma ... publication is also featured as one of BMJ Open ... last year that are most frequently read. Ed ...
(Date:2/11/2016)... 2016  Spectra BioPharma Selling Solutions (Spectra) is ... biopharma companies the experience, expertise, operational delivery and ... sales teams. Created in concert with industry leading ... strategic and tactical needs of its clients by ... both personal and non-personal promotion. ...
Breaking Biology Technology: