Transmission electron microscopy enables analyses of ultrastructural characteristics of biological samples. These samples consist mainly of elements with low atomic numbers, which results in the micrographs that lack contrast. To enhance the contrast, we use contrast agents mostly based on ions of heavy metals. The recent development of new alternative contrast agents enables an easier preparation of biological samples. New protocols are usually tested on different human and mammal samples. In these study, we used two new and rarely used contrast agents AU ZeroTM and sodium silicotungstate for preparation of fish tissue, insect tissue and plant viruses for transmission electron microscopy. We compared and evaluated the acquired micrographs with respect to conventional protocols. The results of imaging the ultrathin sections of fish liver and of insect muscle showed that agent AU ZeroTM generally adequately contrasted these samples and it enabled us to resolve the ultrastructure of our samples. Differences were observed in the case of heterochromatin and lipid droplets imaging in fish hepatocytes. The micrographs of samples in suspension showed that sodium silicotungstate is generally appropriate for detection and observation of tomato mosaic virus but did not enable a more precise observation of the virus’s ultrastructural characteristics.
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