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__//**Article Summary:**//__

Oliveira, Anderson G. et al. “Evidence that a single bioluminescent system is shared by all known bioluminescent fungal lineages.” Photochemical & Photobiological Sciences. **2012.** //11//; 848-852. [|DOI: 10.1039/C2PP25032B]
 * __Evidence that a single bioluminescent system is shared by all known bioluminescent fungal lineages.__**

__Abstract:__ -Researchers have attempted to determine the mechanism for fungal luminescence. -The involvement of a luciferase enzyme was proven only recently. -Only 71 species of fungi are known to be luminescent. -The biologists involved in this study have attempted to prove that luminescent fungi share a single bioluminescent system through cross-reaction experiments.

__Introduction:__ -All luminescent chemical reactions involve a luciferin and luciferase, but not all of these molecules are the same across species. -Bioluminescent fungi have not been studied extensively. -Only 71 of a total 100,000 species of fungi are bioluminescent, and all belong to the order Agaricales. -The species of luminescent mushrooms are unevenly spread out among four lineages. -Only recently was the involvement of a luciferase in the bioluminescent reactions of fungi proven. -The hypothesis that the same enzymatic reaction occurs in all known species would be supported by evidence for a common substrate and enzyme in all four lineages of bioluminescent fungi.

__Experimental:__

//Fungal species:// -Seven different species of luminescent fungi were collected and preserved for this experiment.

//Culture conditions:// -Mycelia were grown on petri dishes containing agar medium and harvested after 10 days, with the exception of Gerronema viridilucens, which was grown on a sugar cane molassus/yeast extract medium. -The samples were cut into 2 cm cubes and used immediately in the chemilluminescence assays. -Mycena luxaeterma and Neonothopanus gardneri were also stored at room temperature after being dried in a vacuum desiccator with CaCl2.

//Hot and cold extracts:// -Hot extracts were prepared with either lycophilized sampes or fresh mycelia. -The dried powder of mycelia was placed in vials and sealed (20 mg per vial) and the air was replaced with argon. The powder inside each vial was extracted with 80°C extraction buffer and homogenized with a stream of argon gas in an 80°C water bath for 1 minute. The vials were then cooled in an ice bath. This extracts the luciferin. -Cold extracts were prepared similarly using 5mL of cold extraction buffer. The extract was centrifuged and the supernatant was stored in ice until use. -Protein concentrations were measured with the Bradford assay.

//Chemiluminescnence assay:// -The assays were performed at 25°C in 12x50 mm test tubes with a luminometer. The integration time was 0.2 s, the sensitivity was set to 100%, and the emission intensities were measured in RLU (relative light units). -200 uL cold extract, 50 uL of 1 g/L BSA, 50 uL of hot extract, and 50 uL NADPH in extraction buffer was used. -The standard chemiluminescence assay was used on some species. -The experiments were conducted in triplicate; the observed average error was 10%. -Integrals for each light emission profile were calculated from 0 to 180 s.

__Results and Discussion:__

//Cross-reactivity of hot/cold extracts from Armillaria, Lucentipes, Mycenoid and Omphalotus lineages// -A complete cross reaction study had not been done before using the four lineages of bioluminescent fungi. -Enzymes have previously been proven to mediate the light emission from fungi. -Light emission was obtained from all combinations of extracts from the fungi used in this study. -Extracts from non-luminescent fungi did not cross-react; therefore luciferin is not a ubiquitious requirement for fungi metabolism. -//N. gardneri// and //M. Luxaeterna// may contain the highest amounts of luciferin and/or luciferase because their cross-reacted extracts produced the most light.

//Phylogenetic significance:// -The data obtained from this assay study support the hypothyesis that bioluminescent fungi lineages share an enzymatic mechanism, and perhaps similar luciferin and luciferase molecules as well. -This may support a single evolutionary origin for the reaction in fungi.

__Conclusion:__ -Cross reactions in all possible combinations of hot and cold extracts from the four lineages of bioluminescent fungi are possible. -Cross reactions with similar non-luminescent species did not work. -Therefore, the four lineages must share a similar mechanism for the bioluminescent reaction.