AABRE: NETWORKING IN PUERTO RICO
PR-AABRE Researcher: Anastacio Emiliano, Ph.D., Department of Chemistry and Physics, University of Turabo
Cluster: Drug Design and Delivery
Collaborator: Sharon Cantrell, Ph.D. (UT)
Consulting Scientist: Abimael Rodríguez, Ph.D. (UPR, Río Piedras Campus)
Mentor: Néstor Carballeira, Ph.D. (UPR, RP)
Project Title: Potentially Bioactive Metabolites from Tropical Fungi
FUNGI DIGEST FOOD OUTSIDE THEIR BODIES by releasing enzymes that decompose organic matter in the surrounding environment. Most vascular plants could not grow without symbiotic fungi, or mycorrhizae, that inhabit their roots and supply essential nutrients by breaking down complex food sources—animal corpses and plant litter, for example—into smaller components they can absorb.
As the planet’s composters and recyclers, fungi both cause and cure a number of diseases. One of the most common mycotic infections, Athlete’s Foot, is caused by a fungus. One of the most well known antibiotics, penicillin, is derived from a fungus.
“Fungi are producers of antibiotics, but in the Caribbean, they have not yet been studied for this purpose,” says Professor of Chemistry Anastacio Emiliano. Emiliano’s research team is investigating fungal strains living in tropical marine environments around the island of Puerto Rico, for example in solar salterns, marine sediments, and mangrove trees. They also study fungi that live inside of the leaves of the Coccoloba uvifera (sea grape plant). These fungi may produce bioactive secondary metabolites— metabolic wastes that are significantly toxic to another organism. The researchers isolate these metabolites and test their bioactivity toward two of the major infections affecting humans today, tuberculosis and malaria.
Mycologist Sharon Cantrell provides fungi samples and together, the researchers decide whether the samples fit their criteria for further study. If so, they grow a small culture to test its ability to inhibit bacteria growth. They then mix the culture with a solvent in a laboratory blender and extract the compound. The remaining culture is concentrated, dried, and tested for toxicity, using brine shrimp to determine the smallest quantity or effective dose necessary to kill fifty percent of the shrimp (ED50). If the ED50 is at or below 200 parts per million, the researchers proceed to the second phase of testing by culturing 10-12 liters of the fungi and following through with column chromatography. They isolate and fractionate the compounds and repeat the ED50 test on the shrimp.
At this point, the scientists perform more chromatographic and spectrographic tests to identify the bioactive compound. If the compound has not been previously identified, its bioactivity will be tested toward malaria and tuberculosis.
These diseases, once believed to be virtually eradicated by drugs and pesticides, have developed multidrug resistances. According to the World Health Organization (WHO), among infectious diseases, TB remains the second leading killer of adults in the world with about 1.7 million TB-related deaths each year. One third of the world’s population is infected with tuberculosis, and during the next decade the WHO estimates that 300 million more people will become infected; 90 million will develop the active disease; and at least 30 million people will die. Malaria kills an estimated 1.5 million people each year, most of them African children. One child dies of malaria every thirty seconds.
Emiliano believes that fungi living in highly saline tropical waters or inside plants as endophytes (fungi living within a plant’s leaves but not necessarily parasitic) may be the key to solving problems caused by drug-resistant microbes.
aemilian@mail.suagm.edu
