Aug 06 2014 : Mirror (Pune)
Ants show the way to new antifungal drugs
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Researchers are collecting samples of antifungal bacteria found on various species of Brazilian ants that could fight off everything fungal and viral infections to cancer and Chagas disease
In the Atlantic Forest of Brazil, leaf-cutter ants carry fresh foliage back to their home colony. There, the partially digested leaves nourish a “garden“ of white fungus that the ants cultivate to feed their larvae, their queen and other ants that never leave the nest.Like human gardeners, the fungus-farming ants must protect their crop from invaders. The parasitic fungus Escovopsis poses a constant threat. Fortunately, the ants have an ally: Pseudonocardia bacteria. During more than 45 million years of symbiosis with the ants, the bacteria have evolved to produce specific antifungal compounds that kill invading Escovopsis while sparing the good fungus. The ants, meanwhile, have evolved special pockets and glands in their bodies to house and feed their bacterial partners.
A team of scientists from the US and Brazil hopes that studying the compounds these bacteria produce will lead to new drugs that combat invasive fungal infections in people, as well as new treatments for cancer and parasitic diseases.
The idea is rooted in history. Pseudonocardia belongs to a group of actinobacteria that has already provided most of the world's antibiotics as well as antifungals, antivirals, anti-clotting drugs and more. And the fungus they fight for the ants is related to fungi that cause life-threatening human disease. To date, no one has gone hunting for natural compounds in the fungusfarming ant ecosystems.
“I'm very excited. I think this project has a good chance of success, and I think it aligns ecology and drug discovery in a way that we haven't tried before,“ said Jon Clardy from the Harvard Medical School, who will co-lead the team with Monica Pupo of the University of Sao Paulo.
INCREDIBLE OPPORTUNITY
More than 200 kinds of fungus-farming ants live in South and Central America. Many of them make their homes in the diverse biomes of Brazil. Each colony may host a slightly different strain of bacteria that makes slightly different compounds to fight a slightly different invader. “We have an incredible opportunity to rigorously evaluate biodiversity in the context of therapeutic discovery and ecology,“ said Clardy.
The team's main focus will be discovering antifungal agents. The world is in desperate need of new antifungal medicines. Invasive fungal infections those that spread inside the body, as opposed to superficial infections of the skin and nails are on the rise, new strains are emerging and infections are getting resistant to drugs.
“Worldwide, more people die of invasive fungal diseases than die of malaria or tuberculosis,“ said Clardy. “What's scary is it's not widely appreciated how dangerous these diseases are because the incidence is quite low, but the mortality is typically very high.“
Aspergillosis, for example, may only affect about 2,00,000 people worldwide, but it has a mortality rate between 30 to 95 per cent. Fungal infections are a top cause of infection-related death in cancer and transplant patients.
In addition to antifungals, the team will look for natural products that could become anticancer drugs. Many chemotherapeutics act in a similar way to antifungals: They spare slowergrowing cells (like those of ants, beneficial fungi and humans) while killing faster-growing cells (like those of invading fungi and tumours). In fact, many chemotherapy drugs were originally developed as antifungals, including the immune suppressor rapamycin, which was found in soil-dwelling actinobacteria on Easter Island.
The team's third goal involves searching for antiparasitics to help treat Chagas disease, also known as the New World version of African sleeping sickness, and leishmaniasis, both of which the World Health Organisation has named neglected tropical diseases. Chagas disease is a particular burden in Brazil, where it kills as many each year as tuberculosis.
A team of scientists from the US and Brazil hopes that studying the compounds these bacteria produce will lead to new drugs that combat invasive fungal infections in people, as well as new treatments for cancer and parasitic diseases.
The idea is rooted in history. Pseudonocardia belongs to a group of actinobacteria that has already provided most of the world's antibiotics as well as antifungals, antivirals, anti-clotting drugs and more. And the fungus they fight for the ants is related to fungi that cause life-threatening human disease. To date, no one has gone hunting for natural compounds in the fungusfarming ant ecosystems.
“I'm very excited. I think this project has a good chance of success, and I think it aligns ecology and drug discovery in a way that we haven't tried before,“ said Jon Clardy from the Harvard Medical School, who will co-lead the team with Monica Pupo of the University of Sao Paulo.
INCREDIBLE OPPORTUNITY
More than 200 kinds of fungus-farming ants live in South and Central America. Many of them make their homes in the diverse biomes of Brazil. Each colony may host a slightly different strain of bacteria that makes slightly different compounds to fight a slightly different invader. “We have an incredible opportunity to rigorously evaluate biodiversity in the context of therapeutic discovery and ecology,“ said Clardy.
The team's main focus will be discovering antifungal agents. The world is in desperate need of new antifungal medicines. Invasive fungal infections those that spread inside the body, as opposed to superficial infections of the skin and nails are on the rise, new strains are emerging and infections are getting resistant to drugs.
“Worldwide, more people die of invasive fungal diseases than die of malaria or tuberculosis,“ said Clardy. “What's scary is it's not widely appreciated how dangerous these diseases are because the incidence is quite low, but the mortality is typically very high.“
Aspergillosis, for example, may only affect about 2,00,000 people worldwide, but it has a mortality rate between 30 to 95 per cent. Fungal infections are a top cause of infection-related death in cancer and transplant patients.
In addition to antifungals, the team will look for natural products that could become anticancer drugs. Many chemotherapeutics act in a similar way to antifungals: They spare slowergrowing cells (like those of ants, beneficial fungi and humans) while killing faster-growing cells (like those of invading fungi and tumours). In fact, many chemotherapy drugs were originally developed as antifungals, including the immune suppressor rapamycin, which was found in soil-dwelling actinobacteria on Easter Island.
The team's third goal involves searching for antiparasitics to help treat Chagas disease, also known as the New World version of African sleeping sickness, and leishmaniasis, both of which the World Health Organisation has named neglected tropical diseases. Chagas disease is a particular burden in Brazil, where it kills as many each year as tuberculosis.
