Linkage between light microscopic observations and molecular analysis by single-cell PCR for ciliates

The molecular analysis of ciliates for identification and phylogeny is usually conducted through PCR amplification and DNA sequencing, with DNA extracted from a large number of cells. Therefore, the analysis of ciliates is limited to only those species that can be cultured. We propose a single-cell PCR procedure to overcome the difficulty in the analysis of unculturable species. The procedure has been tested on 6 Stichotrichia strains and uncultured Levicoleps biwae cells, targeting 18S rRNA gene sequences, after carrying out microscopic observations and obtaining photographic records. This procedure enables the systematic analysis of unculturable ciliate strains in natural environments by linking the morphology and genotype of a single cell.