Ref ID : 7750
Pilar Alonso; Comparative Study of Micro- and Amicronucleate Clones of Euplotes aediculatus Pierson. Protistologica XXI(3):289-294, 1985
Reprint
In File
Notes
Amicronucleates have been detected in a strain of Euplotes aediculatus Pierson maintained in culture for several years. Ten amicronucleate (ami) and eight micronucleate (mi) clones have been established, and their behaviour and growth rate have been compared. No marked differences have been found in both types of clones; even selfing occurred in every clone, although its frequency varied for each one. In the mi-clones, the development of the exconjugants followed the general pattern observed for normal conjugations, although a low percentage of no viable exconjugants was always recorded. In contrast, none of the ami-exconjugants survived. Curiously, most of the partners in ami-couples exhibited macronuclei with reorganization bands. Macronuclear fragmentation in ami-clones started before separation of the partners; and young exconjugants, normal in shape, possess 3-4 macronuclear fragments. Soon afterwards, such individuals became more and more swollen untill their bursting. Such a phenomenon is closely related to a misfunction of the contractile vacuole, since its contractility became gradually slower until its total arrest. Thus, the death of the exconjugants in ami-clones is due not only to the lack of oral reorganization but also to the blockade of the osmorregulation process.