Tetrahymena-specific biomass evaluation with a DNA-based method

Abstract

Evaluating the biomass of a specific taxon or that of a certain nutritional level is especially important for understanding an ecosystem. Although various methods are available, there is still a lack of a universally accepted approach for taxa-specific biomass evaluation. Taking cultured unicellular Tetrahymena as an example, the present study is aimed at exploring and highlighting a DNA-based method for taxa-specific biomass estimation. Results indicated that the Tetrahymena DNA yield increased linearly with increasing number of Tetrahymena cells (p < 0.001). The intra and inter real-time quantitative PCR (Q-PCR) assays were highly reproducible, and Q-PCR quantifying 18S rDNA could detect an equivalent quantity of a single cell or less. Tetrahymena-specific biomass then can be determined according to the rDNA copies quantified by Q-PCR (p < 0.002), considering both of species richness and evenness (indicated by the pooled cells of Tetrahymena species with different ratios). Observations of the present study together with some others suggest that it is possible to quantify a target micro-biomass in natural ambience via specifically-amplified genes.