Application of method of OTE staining of ultrathin sections based on example of microsporidia (Protozoa: Microsporidia)

A comparative analysis of ultrastructure of some organelles stained by different methods of staining of ultrathin sections has been performed using the example of intracellular parasites, i.e., microsporidia. The distinctive peculiarities are revealed and the advantages and disadvantages are substantiated of the traditional method of contrasting with uranyl acetate and the nontraditional method of contrasting using black Chinese tea extract, i.e., oolong tea extract (OTE). The OTE-staining method dies the basic intracellular structures of microsporidia, which is a matter of taxonomic significance; it also reveals additional layers of the polar filament with more distinct boundaries between them. However, traditional UA-staining better reveals some structures (membranes, layers of envelope of mature spores, structure of the rough endoplasmic reticulum, Golgi complex, nuclear chromatin) and provides for higher general contrast. The OTE solution is safe to use and can be longer kept in light at room temperature without losing its activity. However, the OTE-method is time-consuming. Hence, this staining method has both advantages and disadvantages. On the whole, it can be used as an alternative to the traditional staining with uranyl acetate.