in vivo;left dorsolateral view
Acineria incurvata DUJARDIN,1841 a pleurostomatid ciliate found in heavily polluted freshwater and marine habitats. The distinctive oral bulge recurves dorsally and to the left at its anterior end. The bulge has a helical structure like a two-stranded string.The dorsal brush consists of a single file of obliquely oriented dikinetids bearing non-motile clavate cilia. Collected from effluent of a protein skimmer at a commercial saltwater aquarium in Boise,Idaho. January 2007.DIC. Image by Bill Bourland, he uses a Zeiss Axioskop 2 with a Spot Insight CCD camera (Diagnostic Instruments). Image copyright: William Bourland, image used under license to MBL (micro*scope).
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From the collection
Marine microbes from Idaho
|Description of Acineria incurvata: Acineria incurvata (DUJARDIN,1841) Body laterally compressed, outline more or less long and ellipsoid; rather polymorphic; right side with about 12 rows of cilia; left side with only 4 rows in the dorsal part, ventral part of the left side without cilia; mouth slit-like in the ventral part of the anterior region, trichocysts at the edge of the mouth slit; the left ventral region just behind the mouth is somewhat concave and hyaline;
Freshwater and marine. Body length about 45-200 um, but abnormal, giant individuals up to 500 um showing most organelles duplicated. Body oblong, slightly contractile, laterally compressed, rounded posteriorly, narrowing anteriorly to a blunt point. Rather variable in shape (slender to wide and plump) depending on nutritional condition. Ventral side more or less convex, dorsal side straight or concave in the anterior, convex in the posterior region. Excavated region conspicuous, shining brightly. Anterior-most dorsal top somewhat refractive, due to the rolled up oral slit. Macronucleus in two spherical to ovoid parts with a single micronucleus between them. Macronuclear parts fuse during bipartition and divide in the later fission stages. Single contractile vacuole at the posterior pole, diameter about 7 um, with 5-8 pores on the right lateral side. Cytoproct terminal, a slightly laterally located slit. Pellicle soft, flexible, with longitudinal furrows in which the cilia and bristles originate. Furrows disappear in well-fed individuals extrusomes straight to slightly fusiform, thin, about 4 um long, located along the cytostome, a small accumulation of them in the ventral side of the posterior end and even a few scattered throughout the body. Cytoplasm of normally-fed specimens rather clear, containing some small colourless spheres. Carnivorous, feeds on small hymenostome ciliates, e.g. Colpidium, Cyclidium, Glaucoma, Pseudocohnilembus, Loxocephalus, Uronema. Starved individuals feed even on 'cysts' of Euglena viridis and perhaps on bacteria. Ingestion vacuoles rather large, dividing quickly into smaller food vacuoles. Movement moderately quick, gliding on the bottom of the petri-dish or swimming in rotation along its longitudinal axis. Bipartition by transverse fission. Three different types of cilia: (1) normal cilia, about 10 um. (2) short bristles, about 0.5-1.0 um, (3) club-shaped bristles, up to 2.0 um. Eleven longitudinal kineties with cilia type 1, about 8-9 of them on the right and about 3 on the left side. In addition to the normal somatic kineties the following are found on the more differentiated left side: (1) a single kinety with cilia type 2 located to the left of the brosse kinety and often extending only to the middle of the body, its posterior basal bodies less closely spaced, (2) one brosse row of obliquely arranged, paired bristles (cilia type 3) being posteriorly continued by a row of unciliated kinetosomes (or by kinetosomes with very short bristles only), (3) one kinety consisting apically of 2-3 cilia of type 3 (probably consistuting a rudimentary brosse row) and being continued by a few unciliated kinetosomes (about 5 in the anterior third and about 3 kinetosomes in the middle of the body). Kahl (1926, 1931) described the brosse as being built up to of 3 rows of bristles. Foissner (1977/1978) observed only a file-shaped structure there, most probably suggest by the single row of paired brosse-bristles. Cytostome more or less curved, anterior overlapping to the left side but not to the right. Perioral kinety 1 left of cytostome, with paired basal bodies along the mouth, however, only the anterior basal body each bearing cilia of type 2. Perioral kinety 2 and 3 to the right of the oral slit showing closely spaced basal bodies and constituting the so-called 'mane', a conspicuous compact ciliature. Perioral kinety 2 with paired basal bodies along the oral slit, the anterior basal body bears a cilium of type 1. This kinety appears unciliated post-orally. Perioral kinety 3 with single basal bodies but ciliated along the whole body with cilia type 1.The silverline system is a linearly oriented fine-meshed lattice.