Electron Microscopy of Cell Walls of Saccharomces cervisiae and Mycobacterium phlei in the process of DNA extraction

Saccharomyces cerevisiae와 Mycobacterium phlei에서 DNA유출에 따른 세포벽의 전자현미경적 고찰

DNA's were extracted from Saccharomyces cerevisiae and Mycobacterium phlei and the damaging cell walls of these microoragnisms were examined under an electron microscope in the extraction process in which a number of physico-chemical tratments of cells was involved. While the DNA was easily extracted from S. cerevisiae using conventional meylelded very little DNA, of M. phlei was extremely difficult to isolate and yielded very little DNA, applying various methods of isolation published earlier. When the cell walls of S. cerevisiae were examined with the electron microscope, they were not yet damaged even after the cells were treated with sodium lauryl sulfate(SLS) and ethylene diamine tetracetic acid(EDTA), but they were completely destroyed by the treatment of sodium perchlorate followed by the addition of chloroform and a vigorous agitation. Oozing cytoplasm through the broken cell walls was also observed. In the extraction of DNA from M.phlei, the pronase was not effective at the aerobic environment of the sample. When phenol was applied at the last step of DNA isolation, an extreme damage mass yielding little DNA into the solution. Unlike the cells of S.cerevisiae.M.phlei cells showed a tendency of aggregation, thus the destruction of cell walls by sodium hydroxide was seen only on the walls of peripheral cells in the aggregated mass, leaving the walls of the inner cells undamaged.