Science and Technology
15.10.2010

Study Enzyme helps control infections by fungi and protozoa

Recently, at UFRJ, structures were analyzed in the fungi Candida albicans and Candida parapsllosis

Scientists around the world seek to understand the processes that cause the infection of various diseases, so they can develop appropriate treatments. It's what makes Professor José Roberto Meyer Fernandes, Institute of Medical Biochemistry (IBqM) UFRJ, which conducts research on parasitic protozoa and fungi. He studied ecto-enzymes, types of enzymes that are the first molecules of the invading organisms to get in contact with the host. Recently, the professor examined these structures in the fungi Candida albicans and Candida parapsllosis, which yielded two publications in international journals.

The enzymes are mostly protein biomolecules that accelerate chemical reactions inside cells. According to José Roberto, ecto-enzymes are enzymes that expose their catalytic sites (sites where chemical reactions occur) outside the cell of a unicellular organism or a tissue. The study of Candida albicans fungi that can cause oral and vaginal infections, was focused on one type of ecto-enzyme, ecto-phosphatase. "We have worked with the characterization of these enzymes with the pathogens live, intact, under the conditions of infection," says the professor.

He found that Candida albicans isolated, if obtained from HIV-positive patients has a higher activity of ecto-phosphatase. "Thus, treatment of fungi with specific inhibitors of this enzyme is effective against infection," he concluded. The work was published in Oral Diseases

The teacher's group also studied other ecto-enzyme, ecto-ATPase in a pathogenic fungus, Candida parapsllosis that affects immunocompromised individuals, especially those infected with HIV. The research led to a recent article published in FEMS Yeast Research, whose results show that this enzyme inhibitors to dramatically reduce the infection of cells by Candida epiteilais parapsllosis.

The professor and his group of doctoral students, master's and undergraduate research proposing since 2001 that the ecto-enzymes are mechanisms that allow the invasion of the host. This finding has been confirmed by other researchers in several countries and is already the subject of several reviews published. "In the case of ecto-ATPases, we have evidence both in fungi and in protozoa such as Leishmania, that there is their participation in the process of drug resistance," says the scientist.

In an article published in Experimental Parasitology, 2006, for example, he showed that Leishmania amazonensis (causative agent of cutaneous leishmaniasis) with increased ecto-ATPase activity infects more host cells than those with less activity in this direction. The work also showed that blocking this enzyme with specific antibodies reduces the infection of macrophages (large cells of connective tissue).

Source: UFRJ