Ref ID : 4853
Giovanna Rosati; Entry of Foreign Bacteria and of its Own Epibionts (Epixenosomes) into an Hypotrichous Ciliate, Euplotidium itoi, by Cortical Invaginations. Arch.Protistenk 144:283-288, 1994
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A characteristic feature of Euplotidium itoi is the cortical band which contains epixenosomes. In some specimens the formation of deep cortical invaginations has been observed in the cortical band. These invaginations contain foreign bacteria and a few epixenosomes. Successively, intracellular vacuoles are formed, delimited by the whole cortex with the plasmamembrane inward and the alveolar system toward the ciliate cytoplasm. No signs of digestion could be observed within these vacuoles. The alveolar system is gradually dissolved in small regions. Very likely, bacteria and epixenosomes escape from the vacuole at these sites which are delimited by a single unti membrane only. Once in the Euplotidium cytoplasm bacteria are surrounded by rough endoplasmic reticulum membranes. The significance of this process, quite unusual in ciliates, is far from being understood; it is not even clear whether epixenosomes have a role in it and why it takes place only at the level of the epixenosomal band. Moreover is not known what happens to the episymbionts once introduced inside the host cell. As far as bacteria are concerned, the constant alterations of mitochondrial features found in specimens with cortical vacuoles, suggest an infectious nature.