RT Journal Article SR Electronic T1 Improved methods for bulk cultivation and fixation of Loxodes ciliates for fluorescence microscopy JF bioRxiv FD Cold Spring Harbor Laboratory SP 2022.05.29.493905 DO 10.1101/2022.05.29.493905 A1 Brandon Kwee Boon Seah A1 Christiane Emmerich A1 Aditi Singh A1 Estienne Swart YR 2022 UL http://biorxiv.org/content/early/2022/05/29/2022.05.29.493905.abstract AB Loxodes is one of the best ecologically characterized ciliate genera with numerous intriguing physiological abilities, including gravity-sensing organelles and nitrate respiration. However, these cells have been considered challenging to cultivate in bulk, and are poorly preserved by conventional fixatives used for fluorescence microscopy. Here we describe methods to grow and harvest Loxodes cells in bulk with liquid soil extract medium, as well as a new fixative called ZFAE (zinc sulfate, formaldehyde, acetic acid, ethanol) that can fix Loxodes cells more effectively than buffered formaldehyde or methanol. We show that ZFAE is compatible with immunofluorescence and the nuclear stain DAPI. Loxodes is thus now amenable to long-term maintenance, large-scale growth, and modern cell biology investigations of monoclonal strains in laboratory conditions.Competing Interest StatementThe authors have declared no competing interest.