Investigation of effects of pest controlling methods including alternative fumigants of methyl bromide on DNA of museum objects.

点击翻译按钮获取中文摘要

Treatments for pest eradication on museum objects are often indispensable. But such treatments sometimes cause adverse effects on museum objects. When we look at natural specimens, DNA analysis for taxonomic studies have become increasing common. But some conservators had become concerned about the possibility that some fumigants may adversely affect DNA molecules of natural specimens. Thus we investigated the effects of fumigants which have been used for museum collections on DNA of especially natural specimens in this research. The effects of several treatments for pest eradication on natural specimen DNA were examined using freeze-dried mushroom and freeze-dried muscle. The data clearly showed that the fumigants methyl bromide, methyl bromide/ ethylene oxide mixed gas, ethylene oxide, propylene oxide, and methyl iodide all caused significant degradation of specimen DNA, even with a single fumigation. Subsequent steps at amplification of certain DNA fragments by PCR (polymerase chain reaction) were difficult in these samples. There were more problems in amplifying larger DNA fragments than smaller fragments. The main cause of the decreased efficiency of PCR was thought to be the degradation of template DNA. On the other hand, thermal methods (heating and low temperature), 60 percent carbon dioxide treatment, and fumigation by sulfuryl fluoride seemed scarcely to affect the DNA molecules of the specimens, allowing subsequent PCR to be successfully performed. Direct sequencing of the PCR products was also performed to check the possibility of modifications to the DNA sequences. When the PCR products were amplified to the sufficient amount for the direct sequencing, the DNA sequences were normal in our examination of the few gene regions.