| Soil protozoan as a large assemblage of protozoa plays an important role in the soil ecosystem. There are similarities and difference between soil protozoa and aquatic protozoa. Especially, soil ciliates, their unique living conditions, cell structure and physiology could adapt to the soil life. Encystment and excystment are one part of the soil protozoa life history, which takes an important effect on its survival. At present the scientists in many fields focus on ciliate lived in water, but there are no more studies on soil ciliates. Most studies on the ciliates are remain in the ecological functions, community characteristics and species distribution, etc., only a few small ciliates were observated on physical characteristics and its internal. In this study, we used Territricha stramenticola as the experimental material of soil ciliates, applying transmission electron microscopy(TEM) and the RAPD technology, not only in the microscopic level and sub-microscopic level, to observe and compare the structure and ultrastructure of the external morphology of the encapsulation, the ciliate cortex, the cytoplasm and its various organelle of Territricha stramenticola, but also, from gene level, the macronuclear DNAs of the normal cell and encapsulation of Territricha stramenticola were compared and studied. The results are as follows:1 The inner ultrastructure of the vegetative cell and cyst of Territricha stramenticolaThe inner ultrastructure of Territricha stramenticola is observed by using transmission electron microscopy. We found that its surface membrane is composed of the plasma membrane and the cell membrane. We also observed that there is dense fiber bundles close to ventral surface membrane in the Territricha stramenticola.Its lips, ventral cirri and mouth cortex surface membrane of material gathered under the formation of thick fiber bundle or fiber tape. These fiber bundle structure allows Territricha stramenticola's surface membrane be reinforced caterpillar to adapt its crawling life in the soil.The cyst of Territricha stramenticola contains large amounts of mitochondria cyst caterpillars and food bubbles, which may be related to food digestion and energy storage. Largest nuclear elongated cylindrical, nuclear membrane is not smooth, showing wavy. Chromatin granules scattered in large nuclei, arranged rather sloppy, and some family reunion into a high electron density of the sizes of the clumps, nucleolus high number of scattered large nucleus; membrane is divided into two layers, inner nuclear membrane and outer nuclear membrane. Inner nuclear membrane is thicker, but outer nuclear membrane is very thin.The nuclear pore-like structure makes the nuclear membrane into the dotted line. After the formation of cysts, package cyst becomes one layer.This kind of structure has not been found in other ciliates. Membrane consists of two layers of its composition. During hollow area, of which there are many small membrane separation,was their uniform square chamber.They arranged in neat rows like a square with a circle circuit in cells peripheral.Cysts have two autophagic vacuoles: organelle autophagic vacuoles, and cytoplasmic autophagic vacuoles.2 The comparison of macronuclear DNA from vegetative cell and cysts of Territricha stramenticolaThe macronuclear DNA from vegetative cell and cyst of Territricha stramenticola was comparatively analyzed by using RAPD technology in the paper. The results showed that no fragments produced using 2 random primers, 134 fragments were amplified from macronuclear DNAs of the vegetative cell and the cyst using 30 random primers, of which 54 specific fragments belonged to vegetative cell and 80 fragments were specific to the cyst. There were 20 fragments appearring in both the vegetative cell and cyst. The similarity value was 30%. The data indicated that the structures of the macronuclear DNAs in Territricha stramenticola had perhaps major changes in the process of cyst formation, which were closely related to the change in structural features and metabolic activities and to the physiological and biochemical changes in the resting state.
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