Related Experiment Videos
Neuraminidase activity in acanthamoeba species trophozoites and cysts
J L Pellegrin1, E Ortega-Barria, M Barza
1Division of Geographic Medicine and Infectious Diseases, New England Medical Center Hospitals, Tufts University School of Medicine, Boston, Massachusetts.
Abstract:
Acanthamoeba species, a widely distributed group of free-living amoeba, can infect humans and spread hematogenously after direct interaction with the mucosal surfaces. The mechanism underlying Acanthamoeba damage to the target cell is unknown. The authors report that trophozoites and cysts of Acanthamoeba species exhibit a neuraminidase activity that is membrane associated and released into the culture medium at the start of the logarithmic phase of growth. The enzyme activity is optimal at pH 5 and at 25-30 degrees C. Live parasites release sialic acid from human cells. Therefore, the neuraminidase of Acanthamoeba species could be relevant in the colonization and damage of the sialic acid-rich corneal epithelium and in the alterations of glycolipids associated with meningoencephalitis.
Insights
Acanthamoeba parasites possess neuraminidase activity, releasing sialic acid from human cells. This enzyme may contribute to Acanthamoeba infections, particularly in the eye and brain.
Area of Science:
- Microbiology
- Parasitology
- Biochemistry
Background:
- Acanthamoeba species are ubiquitous free-living amoebae.
- These amoebae can cause human infections, including keratitis and meningoencephalitis.
- The mechanisms of Acanthamoeba-induced cellular damage are not fully understood.
Purpose of the Study:
- To investigate the enzymatic activities of Acanthamoeba species.
- To determine the role of Acanthamoeba enzymes in host cell interactions.
Main Methods:
- Assessing neuraminidase activity in Acanthamoeba trophozoites and cysts.
- Measuring enzyme release into culture medium.
- Incubating live Acanthamoeba with human cells to observe sialic acid release.
Main Results:
- Acanthamoeba species possess membrane-associated neuraminidase activity.
- Enzyme activity is optimal at pH 5 and 25-30°C.
- Live Acanthamoeba release sialic acid from human cells.
Conclusions:
- Acanthamoeba neuraminidase may play a role in colonizing sialic acid-rich tissues like the cornea.
- This enzymatic activity could contribute to Acanthamoeba-induced tissue damage.
- Alterations in host cell glycolipids due to neuraminidase may be involved in meningoencephalitis.