Vorticella


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Vorticella

 

a genus of protozoans of the subclass Peritricha. More than 100 species are widely distributed in salt and fresh waters. Unlike other Peritricha, vorticellae are sessile, attaching themselves to a substrate by means of a nonbranching contractile stalk. The bell-shaped body lacks cilia. On the wide anterior end (adoral zone) is a double row of cilia that usually coalesce into membranelles involuted to the left (in contrast to protozoans of the subclass Spirotricha, whose membranelles curl to the right). The circumoral spiral leads to an oral opening. Vorticellae feed on small organic particles suspended in the water (for example, bacteria and detritus). In asexual reproduction, free-swimming zoospores equipped with a crown of cilia are formed as a result of division. They subsequently acquire a stalk and attach themselves to a substrate. The sexual process is a form of anisogamous conjugation, that is, the fusion of immotile macroconjugants and motile microconjugants. Some vorticellae are ectoparasites of fish.

IU. I. POLIANSKII

References in periodicals archive ?
In Vorticella, a similar expansion of a centrin gene family has been identified and consists of at least one spasmin and six centrins (Maciejewski et al.
Vorticella convallaria cells were grown in a bacteria-containing medium of boiled wheat grass according to the methods of Vacchiano et al.
Infestations associated with ciliates of the epistylid genera Epistylis and Opercularia, the vorticellid genera Vorticella and Zoothamnium, and suctorians of the acinetid genera Acineta, Acinetides and Tokophrya, have been reported from adult Macrobrachium rosenbergii cultured in ponds in Limon Province, on the Caribbean coast of Costa Rica [14, 15, 23].
10.7 4.5 Proales doliaris (Rousselet, 1895) 12.4 11.9 Proalinopsis caudatus (Collins, 1872) 5.2 9.8 Trichocerca longiseta (Schrank, 1802) 4.1 8.0 Protozoa Arcella discoides Ehrenberg, 1843 4.1 10.0 Difflugia corona Wallich, 1864 15.7 7.0 Vorticella sp.
AND ASAI, H., 2002.Phylogenetic relationships between Vorticella convallaria and other species inferred from small subunit rRNA gene sequences.
(2004) have reported 99% and 48% uptake of Zn2+ and Cr6+ by Vorticella microstoma after 96 hrs from the medium, respectively.
They sampled colonies of Carchesium polypinum Linnaeus, 1758 and individuals of Vorticella microstoma Ehrenberg, 1830 attached to transparent plastic films and found growth rates of 1.37 and 1.01 per day for the two peritrichs respectively.
The protozoans observed in the samples were Paramecium, Stylonychia, Euplotes, Chilodonella, Colpoda, Cyclidium, Metopus, Plagiopyla, Tachysoma, Tetrahymena, Vorticella, Oxytricha, Spirostomum, Amoeba and Spathidium.