Trichomonads from Poikilotherms: Nutritional and Physiological Notes*

Abstract

SYNOPSIS. Several trichomonads from poikilotherms ( Hypotrichomonas acosta, Monocercomonas colubrorum and M. sp., Trichomonas batrachorum , and Tritrichomonas augusta ) grew in a nearly‐defined medium to a level of 10–40% that permitted with media containing casein digests; T. augusta (4 strains) grew best. The defined medium contained TEM‐4T (a semisynthetic fat based on beef‐tallow fatty acids) and ascorbyl “palmitate” as sources of fatty acids. Besides ascorbyl palmitate, thiomalic and ascorbic acids, and tocopherol served as reducers and antiöxidants. High concentrations of nucleotides (adenylic, cytidylic, guanylic, and uridylic acids) seemed necessary. Indigo carmine was a useful redox indicator; the flagellates never grew in the oxidized zone. Extra trace elements and amino acids or rich natural media permitted better growth at about 34.5°C—the upper temperature limit for these trichomonads, raising the issue of a biochemical basis of a thermal barrier to the invasion of warmblooded hosts. Except for the limited carbohydrate in the nucleotides, carbohydrate could be omitted, the main substrates being a combination of glycerol, acetate, and gylcero‐phosphate, posing the question of the identity of the anaerobic, presumably non‐glycolytic, energy‐yielding pathway.