Nutritional significance of symbiotic bacteria in two species of hemoflagellates.

Symbiote-free strains of Blastocrithidia culicis and Crithidia oncopelti, obtained by chloramphenicol treatment, were compared nutritionally with normal, symbiote-containing strains. The symbiotic bacteria spare the flagellates requirements for exogenous hemin and for other nutritional factors present in liver extract.