Transfer of culture of a bacterivorous protist Nuclearia thermophila to feeding on monoculture of Escherichia coli

Abstract

Summary To quickly increase the cells number of the cultivated bacterivorous protist Nuclearia thermophila and minimize the diversity of bacteria in culture, for the convenience of bioinformatic processing of the sequencing results, the cultivation of N. thermophila was switched to feeding on monoculture of the bacteria Escherichia coli . Experimental selection of the medium composition showed that the PJ+WG medium with the addition of 2.5% of the LB medium ensures the propagation of E. coli and is suitable for rapid reproduction of many N. thermophila cells. A cell density of 200 cells/mm 2 was reached by the end of the first week and was about 600 cells/mm 2 by the end of the third week, with stabilization at the end of the first month at the level of ca. 700 cells/ mm 2 . The approximate duration of the cell cycle in the first week was about 24 hours, the rate of increase in the number of cells was 1.9 times a day. This enhancement is convenient for transcriptomic study of differential gene expression in the cell cycle. It is highly likely that in such cultivation conditions, many of the early culture cells will be at different stages of cell development.