Nuclear Behavior In The Asexual Division Cycle Of Two Model Protozoa

In this study,fluorescent dye Hoechst33342 was used to observe the asexualized division cycle and the nucleus-size behavior of Stylonychia lemnae and Paramecium caudatum in detail by fluorescence microscopy,and the relationship between nuclei and microtubulinsby ?-tubulin Tubulin immunofluorescence assay at the same phase,so as to clarify the time-course and detailed process of important nuclear events in the asexual division and vegetative phase of the two ciliate nucleus shape.The nuclear behavior of ciliates was compared and discussed,and important results were obtained as follows:1.The first completed the Stylonychia lemnae tail worm under optimum temperature cultivation,asexual division cycle in a complete description of nuclear behavior of size.The division and duration of each period are defined according to the MAC behavior.At 23 ?,the time-course of asexual division cycle was about 18 h.Interphase is about 9 h;Prophase is about 4.5h;The metaphase was about 2.5h.The anaphase was about 1.5h.The telophase is about 0.5h.As the process of asexual secession progresses,the time spent on each period of nuclear action becomes shorter and shorter.The transition of the MAC replication band usually takes place simultaneously.The time of division of the MIC is not fixed,but the first division of the MIC is always completed before the completion of the division of the MAC in the metaphase fusion.During anaphase of asexual division,concentrated microtubule particles was located at both ends of the MIC,and filamentous microtubules radiate from one end to the other around the MIC.The microtubules around the anaphase of MIC form a typical spindle structure.The cleavage furrow was observed outside the worm when the new nucleus division was completed.According to the statistics and observation of the number of micronuclei,it was found that 2 MIC were in the majority under the normal condition,and 3-6 MIC were also frequently present.There was no effect of multiple micronuclei on the feeding,survival and activity of the individual cells.2.Supplemented the continuous observation of the MAC and MIC behavior in the asexual division cycle of Paramecium caudatum under the optimal temperature cultivation,and re-divided each period and duration according to the MIC behavior.Under 25 ? culture conditions,the asexual division cycle of Paramecium caudatum takes about 8.5 hours.The interval is about 2.5h;the early period is about 1h;the middle period is about 1.5h;the later period is about 2h;the final period is about 1h.The combination of Hoechst33342 and immunofluorescence tubulin showed that during the asexual division cycle of Paramecium caudatum,there is no obvious microtubule positioning around the MAC,which is considered to be amitotic.In the vegetative phase,there are dense granular microtubule structures at both ends of the MIC,which emit filamentous microtubules from both ends to the middle;no replication band is produced when the MAC is in the early stage of DNA replication;this article adds the later MAC to fold and occupy the cell most of the area,the process of curling;in the later stage,the MIC completes the division,and the internuclear tube structure will be produced when it is allocated to the future front and rear larvae.After the MIC is allocated,the internuclear tube is broken and disappears in the cell;it appears outside the cell at the end stage In the split groove,most individuals have not completed the MAC division at this time.Such individuals are mostly broken by the swimming of the front and back young ciliates in different directions in the water.