Ref ID : 7725
Werner Reisser and Beate Kurmeier; The Endosymbiotic Unit of Climacostomum virens and Chlorella sp. Symbiotic Features of the Association and Host-symbiont Regulatory Mechanisms. Protistologica XX(2):265-270, 1984
Reprint
In File
Notes
The association of Climacostomum virens and Chlorella sp. was studied for symbiotic features and host-symbiont-regulatory mechanisms. The symbiotic chlorellae are localized in special perialgal vacuoles and support host growth by excretion of carbohydrates. Algal photosynthesis exploits host respiratory CO2 and evolves oxygen which is metabolized by the ciliate. Corroboration of algal and ciliate metabolism enables the association to grow in an axenic inorganic medium when enough light is given. In darkness additional feeding with food organisms leads to the formation of alga-free ciliates which can be infected only with chlorellae formerly isolated from green Climacostomum. Other algae are digested. The size of the endosymbiotic algal population is determined by ecological regulation, e.g. chlorellae are usually not digested but grow according to environmental conditions such as illuminance and available nutrients. Thus experiments demonstrate that the association of Climacostomum virens ad Chlorella sp. shows all the characteristics of a stable endosymbiotic unit with an ecological regulation type.