Ref ID : 7693
Philip G. Carey and A. Warren; The Role of Surface Topography in the Taxonomy of Peritrich Ciliates. Protistologica XIX(1):73-89, 1983
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Relatively few taxonomic studies of Peritrich ciliates have included details of surface features. Although silver staining has become an established technique in the systematics of the group, scanning electron microscopy (SEM) has not fully realised its early potential. The few SEM studies that have been undertaken have revealed a wealth of topographic features suitable for taxonomic analysis, but no attempt has been made to capitalise on those initial findings in subsequent studies. This is due to the fact that peritrich ciliates are highly contractile and normal processing for SEM resulted in gross morphological distortion of the zooid and a loss of surface features. Many different methods of relaxation have been suggested in the literature but none ensure the retention of pellicular details in SEM preparations. In this study two compounds were investigated, the effects of which have been well documented on other ciliates. These were the chlorinated alcohol chlorbutol and the antimitotic agent cytochalasin B. It was found that chlorbutol produced reversible relaxation of the zooids in all five species of peritrichs studied. However cytochalasin B had no effect on contractility even at high concentrations. Other chlorinated alcohols were investigated but chlorbutol proved the most effective. TEM studies were undertaken to discover the mode of action of this relaxant. It is hoped that the visualisation of the true cell surface combined with the careful selection of pellicular features will re-establish SEM based analysis in the revision of this problematical group.