Climacostomum (clee-mack-ost-owe-mum) virens is coloured green by endosymbiotic algae. The contractile vacuole is located in the posterior end of the cell. The buccal cavitiy with the adorale membranelle is visible at the anterior. Differential interference contrast. This picture was taken by Martin Kreutz using an Olympus microscope. Image copyright: Martin Kreutz, image used under license to MBL (micro*scope).
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From the collection
Freshwater ponds of Konstanz (Germany)
|Description of Climacostomum virens: Heterotrich ciliate, dorsoventrally flattened, noncontractile, with well-developed buccal apparatus occupying the anterior 1/3-1 of the ventral surface. Cell length 162-235 microns and width 62-122 microns. Kineties on the left side of the ventral surface are postoral and kineties of the right side extend to the anterior tip of the cell. Torsion of the ventral kineties is evident and is more pronounced in some preparations than in others. A zone without kinetosomes cleaves the postoral kineties into 2 groups. Generally 4 or 5 short kineties approach this zone at a slight angle from the right, whereas the kineties bordering the left side of the zone are approximately parallel to the longitudinal cell axis. The angle of approach and the number of short kineties on the right are variable among cells. A secant zone of kineties occurs on the posterior left lateral or dorsal surface; the exact position depends upon the degree of kinety and cell tortion. All dorsal kineties do not terminate anteriorly at the same level nor do they extend as far as the adoral zone of membranelle (AZM). Kineties of the somatic cortex are uniformly composed of rows of paired kinetosomes. The buccal apparatus consists of an AZM on the left, the apical membranelles on the right, and an intervening peristomal field. Kineties of the peristomal field extend deep into the cell forming a buccal tube at the end of which are located the cytostome. Membranelles of the anterior part of the AZM consists of 2 kinetosomal rows, those of the middle region consist of 3 complete kinetosomal rows. A curtain of nemadesmata lies under the entire length of the AZM. Every apical membranelle is composed of 2 short rows of kinetosomes. The fan of 14 or 15 peristomal field kineties spirals to the left and centripetally, and then kineties descend into the cytoplasm as the buccal tube. Each kinety is composed of a series of ciliated kinetosomal pairs. Phase-contrast observations of the buccal tube of non-feeding cells reveal that the orientation of the cilia frequently reverses, sometimes being directed toward the cytostome and sometimes away from it. The haplokinety is a collar of paired, ciliated kinetosomes which completely surrounds the cytostome. The cell possess numerous algal endosymbiotes. The coiled macronucleus is without nodes and has numerous nucleoli. The macronuclear configuration and position within the cell are variable. Micronuclei are about 2 microns in diameter. |