DNA Analysis Helps Conserve Documents

By identifying paper-degrading fungal species through DNA analysis, important historic documents and medical papers can be conserved.

Conventional methods for identifying fungi are elaborate and imprecise, and they require a large amount of sampling material as well as the propagation and microscopic identification of the sample. Now, a team of researchers in the department of medicinal chemistry at the University of Vienna (Austria), led by Dr. Guadalupe Pinar, has developed a process for quickly and unequivocally classifying fungal species on the basis of their DNA.

The new process is based on the special characteristics of the genetic material of many fungal species: a DNA region known as ITS1, which differs a lot from one strain to another when sequenced. Because each fungal species has its own typical ITS1 region and special fingerprint, large amounts of DNA are required to analyze the sequence differences in molecular biologic relationships. However, large amounts of source material are not possible when dealing with historic documents.

"We are using the polymerase chain reaction (PCR), a highly efficient process for cloning individual DNA regions,” explained Astrid Michaelsen, a member of the research team. "It allows us to produce large amounts of ITS1 fragments with a high degree of purity, even when only very small amounts of fungal material are available for the DNA extraction.”

Once sufficient ITS1 fragments have been cloned, they are applied to a gel that is subjected to an electrical charge. The samples cover different distances depending on the mutations, so each distance is characteristic of a given fungal species. An exchange of even one base pair results in differences that allow the exact species to be identified. Another advantage of this method is that even dead fungi can be used as source material.

Developing restoration and conservation measures that are tailored to each type of fungus will be carried out in cooperation with the Istituto Centrale per la Patologia del Libro (Rome, Italy), which is providing the historical samples.




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University of Vienna