Micronuclear influence on the cell morphological structures in Uroleptus sp.(Ciliata,Protozoa) during asexual propagation

Amicronucleate cell lines of a spirotrichous ciliate Uroleptus sp. were generated by microsurgery. Compared with the normal cells and the micronucleates regenerated after microsurgery, the amicronucleates exhibited a higher rate of abnormality in the cell morphological structures, especially in undulating membranes (UM) and adoral zone of membranelles (AZM). During stationary phase, about 23% of amicronucleate cells (36/155) entirely lost their UM,and these cells showed abnormal AZM at the same time. Furthermore, some amicronucleates showed an abnormal number of macronuclei, e.g., only one macronucleus in some cells and four macronuclei in others replaced the normal two,and the macronuclei divided in the non-dividing phase in a few of the cells. The result suggests that the micronucleus of Uroleptus sp. is indispensable for sustaining the normal cell morphological structures, especially in the stabilization of the oral apparatus, and for maintaining the normal number of macronuclei.