AXENIC PARAMECIUM-CAUDATUM .1. MASS-CULTURE AND STRUCTURE

SYNOPSIS. To establish and grow Paramecium caudatum in mass axenic culture the culture medium of Soldo, Godoy & van Wagtendonk was modified by substituting phosphatidylethanolamine (PE) for TEM‐4T and by a 10‐fold increase in folic acid. Population densities of 4000 to 6000 cells/ml and a generation time of 20–26 h are regularly obtained. Optimal growth is obtained with PE‐stigmasterol ratios between 40:1 to 400:1. Cells from 1‐day‐old axenic cultures have many lipid bodies aggregated in clumps (which disappear in 2 to 3 days) as well as foci of rough endoplasmic reticulum bordered by dictyosomes. The latter suggests a very active metabolism. Crystalline sheets found in both food vacuoles and lysosomes presumably play a role in digestion. Axenically grown cells also have abundant Golgi bodies (dictyosomes) and by late log phase become filled with lysosomes. Copyright © 1979, Wiley Blackwell. All rights reserved