| To reveal ciliates' change of ultrastructure from resting cysts to vegetative cells, and of the location pattern of Y - tubulin , the resting cells , vegetative cells and excysting cells were studied as experimental materials, by using the transmission electron microscope (TEM) , scanning electron microscope (SEM) and immunofluorescence.1. The change of ultrastructure revealed by TEMDuring the period of excystment, Euplotes encysticus cyst wall undergo a process of becoming thinner and breaking. Especially, the inner layer of cyst wall breaks into pieces. The inner structure of macronucleus changes greatly: The chromatin particles of cyst are not well distributed , and the number of nucleoli is not large; While in the midterm of excystment, the chromatin particles are well distributed and the nucleoli merge into a large sphere, and the chromatin attached to the nuclear membrane decrease; in the later stage of excystment and in the vegetative state, the chromatin particles are not spheral any more, but in all sorts of shapes, and the number of nucleoli increase. The inner membrane system becomes complicated gradually, especially the endoplasmic reticulum. Some unknown membranous structures appear. The structure of mitochondriae also changes greatly. The inner membrane of cyst's mitochondriae is vague and the boundary lines are unclear, as contrast with the structure of vegetative cells' mitochondriae which is distinct and it's boundary lines are clear. At the same time, the number of mitochondriae ridges increases. The deteriorated ciliature of cyst reconstruct during the period of excystment. For example, in the later stage of excystment, the microtubular layer appears out ofthe vesicles containing ciliatary shafts, And out of some similar vesicles, microtubule bundles beneath the kinetosomes become obvious and strong. Other structures, such as micronucleus, keep the same morphology, which means it is not relate to the process of excystment maybe. All these results illustrate the great change of inner structure during the physiological transformation from cyst to vegetative cell, and provide more documents for the study on the mechanism of cellular resting and differentiation in ciliates.2. The structure of macronucleus revealed by SEMIn vegetative cells, the appearance of macronucleus is like the word "C", or the digit of "3" when DNA is synthesizing with two replication bands (RB) at each end. The macronucleus contains chromatin particles of lμm, which is constituted of 50nm chromatin grains. The RB is also made up with 50nm chromatin grains. The chromatin particles near to RB are disintergrated. The chromatin particles are linked up with l00nm filaments. In the deep structure, there are complicate nets of filaments. As to the cysts and encysting cells, the inner structure cannot be observed successfully because of the difficulty of extracting intact macronuclei. After comparing with the macronuclear structure revealed by TEM, the existence morphology of DNA is verified. The succeeding research of cyst's and excysting cell's macronuclei by SEM will expand our knowledge of ciliate's chromatin morphology.3. The location pattern of γ-tubulinIn the vegetative cells, all the ciliary shafts are labeled with strong fluorescence, while the macronucleus and micronucleus are not. In the resting cysts, the remnant structures of microtubule on the dorsal side are labeled as "V" structures, and all these "V" structures consist in some arc-like lines. The border of dorsal side and abdominal side are also labeled, while there is not fluoresence in the abdominal side except a circle-like structure. The AZM(aboral zone of membrane) compressed in the cyst is labeled slightly. During the period of excystment, the lines of dorsal fluorensence are broken and form a crevice where the cell goes out. The fluorenscence's location pattern and distribution of Y - tubulin is similar to the a -,β- tubulin's. This phenomenon verifies the tubulin's outlet after encystment.
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