Sea cucumber protein used to inhibit development of malaria parasite

December 26, 2007

Scientists have genetically engineered a mosquito to release a sea-cucumber protein into its gut which impairs the development of malaria parasites, according to research out today (21 December) in PLoS Pathogens. Researchers say this development is a step towards developing future methods of preventing the transmission of malaria.

Malaria is caused by parasites whose lives begin in the bodies of mosquitoes. When mosquitoes feed on the blood of an infected human, the malaria parasites undergo complex development in the insect’s gut. The new study has focused on disrupting this growth and development with a lethal protein, CEL-III, found in sea cucumbers, to prevent the mosquito from passing on the parasite.

Human blood infected with malaria contains parasitic gametocytes – cells which can create parasite sperm and eggs in the gut of the insect. These then fertilise, kick-starting the parasite reproductive process and life cycle by producing invasive offspring called ookinetes.

These ookinetes then migrate through the mosquito’s stomach wall and produce thousands of ‘daughter’ cells known as sporozoites. After 10-20 days these are ready in the salivary glands to infect another human when the mosquito takes a subsequent blood meal.

The international team fused part of the sea cucumber lectin gene with part of a mosquito gene so that the mosquito would release lectin into its gut during feeding. The released lectin is toxic to the ookinete and therefore kills the parasite in the mosquito’s stomach.

In laboratory tests the research team showed that introducing lectin to the mosquito’s gut in this way significantly impaired the development of malaria parasites inside the mosquito, potentially preventing transmission to other people. Early indications suggest that this sea cucumber protein could be effective on more than one of the four different parasites that can cause malaria in humans.

Professor Bob Sinden from Imperial College London’s Department of Life Sciences, one of the authors on the paper said: “These results are very promising and show that genetically engineering mosquitoes in this way has a clear impact on the parasites’ ability to multiply inside the mosquito host.”

However, Professor Sinden explains that there is still a lot of work to do before such techniques can be used to combat the spread of malaria in real-world scenario. This is because although the sea cucumber protein significantly reduces the number of parasites in mosquitoes, it does not totally remove all parasites from all mosquitoes and as such, at this stage of development, would not be effective enough to prevent transmission of malaria to humans.

Professor Sinden says he hopes studies such as this one, which improve scientists’ understanding of the complex process by which malaria parasites are transmitted, will lead to new advances in the quest to prevent malaria.

“Ultimately, one aim of our field is to find a way of genetically engineering mosquitoes so that the malaria parasite cannot develop inside them. This study is one more step along the road towards achieving that goal, not least because it has been shown that more than one species of malaria can be killed in this way.”

About 40% of the world’s population are at risk of malaria. Of these 2.5 billion people at risk, more than 500 million become severely ill with malaria every year and more than 1 million die from the effects of the disease.

Malaria is especially a serious problem in Africa, where one in every five childhood deaths is due to the effects of the disease. An African child has on average between 1.6 and 5.4 episodes of malaria fever each year.

Citation: Yoshida S, Shimada Y, Kondoh D, Kouzuma Y, Ghosh AK, et al. (2007) Hemolytic C-type lectin CEL-III from sea cucumber expressed in transgenic mosquitoes impairs malaria parasite development. PLoS Pathog 3(12): e192. doi:10.1371/journal.ppat.0030192 (www.plospathogens.org)

Source: Public Library of Science

Explore further: Discovery of key molecules involved in severe malaria – new target for malaria vaccine

Related Stories

Discovery of key molecules involved in severe malaria – new target for malaria vaccine

December 4, 2017
Malaria is one of three major infectious diseases affecting approximately 300 million people every year, accounting for about 500,000 deaths, but effective vaccine development has not been successful. Among malaria parasites ...

Dibenzoazepine found to be effective against resistant hepatitis C

December 6, 2017
Hepatitis C is caused by a highly infectious virus affecting millions across the globe and can lead to a variety of liver ailments. While the hepatitis C virus (HCV) can sometimes be fought off and cleared by the immune system ...

A new research agenda to accelerate malaria elimination and eradication

November 30, 2017
More than 180 scientists, malaria programme leaders and policy makers from around the world have come together through a consultative process to update the research agenda for malaria elimination and eradication, first published ...

Protective antibodies following malaria infection

November 28, 2017
No effective vaccine exists to date against the tropical disease malaria. Scientists from the German Cancer Research Center (DKFZ) have now studied how the human immune system responds to natural infection by the malaria ...

A structural clue to attacking malaria's 'Achilles heel'

November 16, 2017
Researchers from The Scripps Research Institute (TSRI) and PATH's Malaria Vaccine Initiative (MVI) have shed light on how the human immune system recognizes the malaria parasite though investigation of antibodies generated ...

Researchers are hunting for a safer supplement to use in malaria-endemic countries

November 23, 2017
Treating iron deficiency—the most common nutritional deficiency in the world—is a double-edged sword. Iron supplements help, but in a paradox that has stymied health efforts for decades, they can also make existing infections ...

Recommended for you

Gene therapy improves immunity in babies with 'bubble boy' disease

December 9, 2017
Early evidence suggests that gene therapy developed at St. Jude Children's Research Hospital will lead to broad protection for infants with the devastating immune disorder X-linked severe combined immunodeficiency disorder. ...

In lab research, scientists slow progression of a fatal form of muscular dystrophy

December 8, 2017
In a paper published in the Nature journal Scientific Reports, Saint Louis University (SLU) researchers report that a new drug reduces fibrosis (scarring) and prevents loss of muscle function in an animal model of Duchenne ...

Double-blind study shows HIV vaccine not effective in viral suppression

December 7, 2017
(Medical Xpress)—A large team of researchers from the U.S. and Canada has conducted a randomized double-blind study of the effectiveness of an HIV vaccine and has found it to be ineffective in suppressing the virus. In ...

Time matters: Does our biological clock keep cancer at bay?

December 7, 2017
Our body has an internal biological or "circadian" clock, which cycles daily and is synchronized with solar time. New research done in mice suggests that it can help suppress cancer. The study, publishing 7 December in the ...

Novel harvesting method rapidly produces superior stem cells for transplantation

December 7, 2017
A new method of harvesting stem cells for bone marrow transplantation - developed by a team of investigators from the Massachusetts General Hospital (MGH) Cancer Center and the Harvard Stem Cell Institute - appears to accomplish ...

Inhibiting TOR boosts regenerative potential of adult tissues

December 7, 2017
Adult stem cells replenish dying cells and regenerate damaged tissues throughout our lifetime. We lose many of those stem cells, along with their regenerative capacity, as we age. Working in flies and mice, researchers at ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.