Usually I focus carefully through the viewed objects to discover the cell organelles and to get an idea of the extension of the viewed beings in the third dimension. In the Nuclearia cell shown in Figure 1 I discovered that it probably had more than one nucleus. At first it was still too mobile, so I could not be sure how many nuclei were actually in the cell. As the water under the coverslip progressively evaporated, mobility became restricted, I was able to take tomographic images and counted six large vesicular nuclei! The rod-shaped bacteria show very vividly the extent of the mucilaginous membrane around the cell. The properties “mucilaginous coat” and “multinucleated, 4-12 nuclei” ensure the identification of the species Nuclearia delicatula.
Fig. 1: Three tomograms of a Nuclearia delicatula cell showing several nuclei. Scale bar indicates 10 µm. Sample from a tropical freshwater aquarium.
Fig. 2:Nuclearia delicatula amongst red alga filaments (Audouinella spec.) Two nuclei are visible. Scale bar indicates 25 µm.
Fig. 3:Nuclearia delicatula on a red alga filament (Audouinella spec.) Nuclei and pseudopods are visible. Scale bar indicates 25 µm.