Fungus Amongus: budding scientist helps solve medical mystery
◉ Hidden Spheres: A 7th grade science fair project has helped uncover the source of fungal infections that target patients with HIV/AIDS. One third of AIDS related deaths have been linked to infections by Cryptococcus. This fungus causes life-threatening infections in immune-compromised patients, and less commonly in healthy people, pets and animals, accounting for >1 million infections and >620,000 deaths worldwide. Named “hidden sphere” because of its tiny spores, Cryptococcus is a single-celled yeast that can propagate by budding, or it can mate in pairs to form spores that are released into the air. Fortunately, it only multiplies by budding in human hosts, and therefore cannot spread from person to person. So how do we acquire it, and what is its natural reservoir?
◉ Love is in the Air? : Cryptococcus gattii grows on the bark and leaves of the Australian Eucalyptus tree. Scientists speculate that the tropical fungus was inadvertently imported into the northwestern US along with the trees, and has spread to ten other tree species in the Vancouver/Oregon area including Coastal Douglas Fir and Coastal Western Hemlock. The fungus depends on chemical stimulants (myo-inositol and indole acetic acid) from plants for sexual reproduction, forming spores that are dispersed in the wind to be inhaled by unsuspecting people. Only mating allows fungal DNA to recombine, forming new, virulent strains that can survive in unfriendly environments such as the warm bodies of humans. After fatal outbreaks were reported in the Pacific Northwest area, patients with AIDS and other immune illnesses have been advised to stay away from forests. Historically, C. gattii has been infecting people in California for years, although the fungus has not been found on eucalyptus trees and other usual suspects there. Tracking down the environmental hideout would help warn susceptible people of the danger in the hidden spheres.
◉ Nailing the Niche : Schoolgirl Elan Filler’s father, a scientist, helped connect her with microbiologist Joseph Heitman of Duke University. For her science fair project, Elan collected fungal samples from local trees, cultured them on petri plates, and sent them to postdoc Deborah Springer who analyzed the DNA and compared it to samples found in patients in the area. They found a perfect genetic match with samples harvested from three species- Canary Island pine, New Zealand pohutukawa and American sweet gum, to patient samples collected in the past decade. With her science sleuthing recently reported in a publication in PLOS Pathogens, here’s hoping that young Elan is inspired to find her niche in research and science!
◉ Science Trivia Challenge! What does V8 vegetable juice (Campbell Soups) have to do with Cryptococcus?
#OpenAccess paper with Elan Filler as co-author: http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1004285
NPR News Story: http://goo.gl/EQa9Pp
C. gatti infections: http://en.wikipedia.org/wiki/Cryptococcus_gattii
H/T KQED SCIENCE for the news find!