Fungi clean up
New knowledge about fungi biochemistry opens doors for better bioremediation options
A new study has revealed the molecule at the heart of what makes fungi excellent cleanup agents for contaminated environments: the highly reactive superoxide, or O2-. The study that gave this insight was led by EMSL users from Harvard University and published in the Proceedings of the National Academy of Sciences. For their work, the research team chose the model fungus, Stilbella aciculosa, which they isolated from a treatment system used to remediate coal mine drainage water contaminated with manganese (Mn), and they focused on Mn reactions. The team found that when Stilbella cells divide, they release superoxide. Hungry to react with the elements that surround it, superoxide oxidizes—or steals an electron from—Mn(II), resulting in the formation of Mn oxides, which are also very reactive. Mn oxides in turn participate in a myriad of chemical reactions with hefty consequences for carbon, nutrient, and metal cycling and availability. For example, Mn oxides help sequester harmful lead and uranium. The research team confirmed the superoxide mechanism, showing that no Mn oxides formed if superoxide scavengers were added to the mix. Giving deeper insight into superoxide biochemistry, the team also showed that no Mn oxides were formed if the enzymes responsible for superoxide production and cell differentiation, NADPH oxidases, were inhibited. Interestingly, these contributions of fungi to the carbon, nutrient, and metal balancing act appear to be of no benefit to fungi, just an unintended side effect—but a side effect that opens new doors for better bioremediation options.
Learn more by reading the Harvard University press release about this work.
Participants: Harvard University, National Museum of Natural History, Stanford Synchrotron Radiation Lightsource
Reference: Hansel CM, CA Zeiner, CM Santelli, and SM Webb. 2012. “Mn(II) Oxidation by an Ascomycete Fungus is Linked to Superoxide Production During Asexual Reproduction.” Proceedings of the National Academy of Sciences 109(31):12621-12625. DOI 10.1073/pnas.1203885109
Acknowledgments: This project was funded by the National Science Foundation. Portions of the research were conducted at two national scientific user facilities: EMSL and the Stanford Synchrotron Radiation Lightsource.
User Proposal: 40062
Released: August 08, 2012