Mechanisms of sampling for electronic microscopic investigation of intestinal viruses

Kashnikov A. Yu.

The aim of the study is to increase the sensitivity of the method of electron microscopic detection of intestinal viruses, which are difficult to detect due to low content in the sample or small size. To solve the task, the preparation of viral preparations was supplemented by some methodical methods, concerning the concentration of viruses and the immobilization on the substrate of electron microscope mesh. The use of techniques that make it possible to detect the intestinal virus in the sample more likely was based on the use of information on the value of the Ct threshold cycle, determined by real-time PCR. To a virus with a low content in the sample (Ct ≥ 20), a modified concentration variant was used to maximize the collection of the virus for detection in an electron microscope. For viruses that are small in size (d ≤ 40 nm), which are difficult to detect by ordinary electron microscopy, special conditions have been created to facilitate their detection among the minor inclusions accompanying them. These conditions contributed to the formation of nonspecific complexes of viral particles. When preparing viral preparations intended for viewing in an electron microscope, conditions were also created that made it easier to search for the virus. For this purpose, the surface of the substrate of the electron microscope mesh was treated with techniques that not only increase the level of adsorption of the virus on the mesh, but also change the nature of its immobilization on it. The positive effect of the proposed methodical techniques is illustrated by electronograms of intestinal viruses.

Keywords:transmission electron microscopy, intestinal viruses, methods of virus concentration, threshold cycle