.: Texas A&M Department of Biology, Lab of Dr. Xiaorong Lin: Cryptococcus neoformans

Cryptococcus neoformans:
Cryptococcus neoformans is the causative agent for cryptococcal meningitis, which is considered an AIDS-defining condition. Cryptococcal meningitis is the most common fungal infection of the central nervous system (CNS) and the third most frequent neurological complication in AIDS patients (> 40 million people worldwide suffer from AIDS). Cryptococcal meningitis can cause up to 30% mortality in AIDS patients in Southeast and Sub-Sahara Africa.

Human infection is acquired by inhalation of airborne fungal cells from environment. Infection is typically asymptomatic, and it can be either cleared or enter a dormant, latent form. When host immunity is compromised, the dormant form can be reactivated and disseminate hematogenously to cause systemic infection with a propensity to the CNS.

Although morphologically similar to the model budding yeast Saccharomyces cerevisiae, Cryptococcus neoformans is a capsulated basidiomycetous yeast, which belongs to a totally different phylum in the fungal kingdom.

Research in this lab is focused on characterization of virulence genes than enable this fungus to cause human diseases. The image above shows a scanning electronic photograph of a mother and daughter Cryptococcus neoformans cells (left). The right panel shows a light microscopic photograph of the yeast capsule due to exclusion of Indian ink.