| Abstract: | The comparative analysis of the ultrastructure of various types of parasitophorous vacuoles (PV) induced by microsporidians is given. The data on the occurrence of PV in the hosts belonging to different systematic phyla are summarised. It is concluded, that the formation of PV around microsporidians might take place either in certain parasite species or in the special type of the invaded cells, or could be connected with the development in the unspecific host. The variety of fine structure of PV might be explained by an extremely broad range of hosts (from protists to mammalians), with different level of development of their immune system (defence reactions). Three basic types of PV are proposed according the organization of their envelopes (walls): (1) a single membrane originated from the host cell plasmalemma (hosts: Aves and Mammalia); (2) a single membrane derived from the host ER (hosts: Pisces); (3) a single- or double-membrane host ER (hosts: protists, invertebrates and animals of other systematic groups). It was assumed that the formation of the PV around microsporidians reflects more primitive host-parasite interactions, than the development of the parasite in a direct contact with the host cell cytoplasm. |
