AsianScientist (Jul. 27, 2011) – A group of scientists, led by Dr. Frédéric Bard at A*STAR’s Institute of Molecular and Cell Biology (IMCB), have revealed a promising method to combat lethal plant toxins such as Ricin, notorious for its potential use in bioterrorism, and Pseudomonas exotoxin (PE), mostly found in hospital-acquired infections.
The new discovery might also be useful for preventing food poisoning outbreaks caused by Diphtheria and Shiga-like toxins, as with the recent outbreak in Germany.
Ricin, a toxin that is abundant in castor beans, is able to kill an adult with the equivalent of half a grain of rice. Once purified, it is a tasteless and odorless powder, say security specialists. As it is 1,000 times more lethal than cyanide and as no antidotes are currently available, it is widely feared as a potential bio-terrorist weapon.
On the other hand, hospital-acquired infections (HAIs) endanger millions of people’s lives around the globe. An estimate by the US Centers for Disease Control and Prevention shows that HAIs result in a cost of US$45 billion and around 100,000 deaths annually.
With an increasing resistance of bacteria to antibiotics, existing treatments for HAIs are becoming less effective. Moreover, in treating food poisoning, doctors may refrain from using antibiotics as killing the bacteria causes more toxins to be released, exacerbating the symptoms of the illness.
Given the two-pronged potential security threat and the development of antibiotic resistance, a potent antidote to these deadly toxins is urgently needed.
Bard and his team used a genome-wide screen to identify the genes interacting with these toxins. Among the 22,000 genes in the human genome, they discovered that a gene called ERGIC2 is essential not only for Ricin but also for PE intoxication.
As ERGIC2 is a key component of the host cell’s internal transport pathway to reach its protein ‘factories,’ it presents an attractive therapeutic target, says Bard. He hopes that scientists will be able to develop a generic antidote that is effective against the two different types of toxins by blocking ERGIC2 function.
The article can be found at: Moreau D et al. (2011) Genome-Wide RNAi Screens Identify Genes Required for Ricin and PE Intoxications.
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Source: A*STAR.
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