Particle capture by Favella sp. (Ciliata, Tintinnina)
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Particle capture by the tintinnid ciliate, Favella sp., was investigated with high-speed video microscopy. Experiments with microspheres and algal cells indicate that within the size range 1–19 p.m. behavioral responses are partly responsible for the differential capture of large over small particles. For example, 4 μm microspheres or Isochrysis [spheiical diameter (ESD) - 4.5 μ are only captured if they are encountered in the inner zones of the encounter area. Ten micrometer microspheres or Heterocapsa(14–19 – are captured with a greater efficiency than smaller particles from the inner zones, but can also be captured from the outer zone of the encounter area. Capture of particles from the outer zone is associated with cilialy reversal. Microsp1ieres and algal cells of similar size are captured in a similar manner.Keywords:
Ciliata
Particle (ecology)
Micrometer
Video microscopy
Particle capture by the tintinnid ciliate, Favella sp., was investigated with high-speed video microscopy. Experiments with microspheres and algal cells indicate that within the size range 1–19 p.m. behavioral responses are partly responsible for the differential capture of large over small particles. For example, 4 μm microspheres or Isochrysis [spheiical diameter (ESD) - 4.5 μ are only captured if they are encountered in the inner zones of the encounter area. Ten micrometer microspheres or Heterocapsa(14–19 – are captured with a greater efficiency than smaller particles from the inner zones, but can also be captured from the outer zone of the encounter area. Capture of particles from the outer zone is associated with cilialy reversal. Microsp1ieres and algal cells of similar size are captured in a similar manner.
Ciliata
Particle (ecology)
Micrometer
Video microscopy
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To the existing genera of sphenophryid ciliates (Sphenophrya, Pelecyophrya, and Gargarius) described by Chatton and Lwoff, a new genus, Lwoffia, is added. The genotype, L. cilifera, was found on the gills of Brachidontes recurvus near Fort Myers, Florida. Functional cilia persist throughout the life history of L. cilifera, and are disposed in two systems on either side of the body, in much the same way as the rows of infraciliature in Pelecyophrya tapetis. The attachment surface is proportionately more extensive than that of P. tapetis, and in form is much like that of species of Sphenophrya. Division produces equal and fully-differentiated ciliates, rather than an ancistrocomid-like embryo from the parent ciliate, and in this respect is similar to division in Gargarius gargarius.
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Abstract The feeding of the marine ciliate Euplotes mutabilis was studied using bacteria (Vibrio natriegens) doubly labelled with 3H-thymidine and 14C-leucine. In the presence of abundant bacteria (30 × 106 bacteria ml−1), an average Euplotes cell (initially without food vacuoles) with a protein content of 12 ng consumed 16 × 103 bacteria in the first hour and 27 × 103 bacteria over four hours, accumulating about 60% of the bacterial protein into ciliate macromolecules. Euplotes which had been starved or under-fed to reduce cell protein biomass to 7 or 9 ng consumed significantly fewer bacteria, but the gross growth efficiency for protein did not change. The rate of consumption of bacteria by large Euplotes of protein content 15 ng was initially less than that of 12 ng cells, and it decreased markedly before the end of a 4-hour experiment. Recently divided cells ingested bacteria rapidly, but showed a reduced gross growth efficiency of about 40%. At low bacterial concentrations (6 × 106 bacteria ml−1) the rates of ingestion were markedly reduced to between 1 2 and 1 3 of maximal levels; the smallest cells could not sustain feeding activity at the low prey concentration and gross growth efficiency fell from 43 to 20% during a 4-hour experiment. The strategy adopted by Euplotes in response to local fluctuations in food supply involves rapid consumption with high growth efficiency in times of plenty, but slow shrinkage without cell division to survive in times of shortage.
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The morphology and ciliature of a new freshwater ciliate, Frontonia apoacuminata sp. nov., isolated from an artificial pond in Qingdao, PR China, were investigated using live observation and silver staining methods. The main features separating F. apoacuminata sp. nov. from its congeners are as follows: a broad elliptical body that is slightly pointed at the posterior end, four ophryokineties, one or two spherical micronuclei of a 'compact' type, a dorsally positioned contractile vacuole, and peniculi 1-3 each with five kinetosome rows though the left-most two rows in peniculus 3 are extremely shortened (with only two or three kinetosomes each). Additionally, an improved diagnosis of F. acuminata is provided. Phylogenetic analyses based on the small subunit ribosomal RNA (SSU rRNA) gene show that F. apoacuminata sp. nov. clusters with F. atra, F. minuta, F. acuminata and F. terricola. These five species group with Disematostoma, Marituja and Stokesia rather than with other Frontonia species, causing polyphyly of the genus Frontonia.
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Contractile vacuole
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Molecular Phylogenetics
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Macronucleus
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ABSTRACT. The identification of Favella ehrenbergii , a marine planktonic ciliate, has largely been based on its lorica features. This approach is potentially problematic given the polymorphic lorica during this organism's life cycle. We isolated a population of F. ehrenbergii from the coastal waters of Incheon, Korea, and revealed its infraciliature using the protargol staining method. Phylogenetic analysis based on small subunit rRNA gene sequences was also performed. Results showed that this population possessed 16 collar membranelles (CM) and about 100 somatic kineties. These features are highly conserved, even in later dividers. As such, the number of CM and somatic kineties can be used as key characteristics for identification of Favella species.
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Protist
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Species identifications of tintinnid ciliates are based on characteristics of the lorica housing the ciliate cell. Molecular characterization of tintinnid ciliates has revealed the occurrence of cryptic species, genetically distinct forms with similar loricas, as well as polymorphic species in which genetically identical forms have distinct loricas. Among this latter category may be forms currently recognized as species of the genus Salpingacantha, erected by Kofoid and Campbell for forms originally described as varieties of species of Salpingella with ‘teeth’ on the margin of the lorica oral opening. Some workers have expressed the opinion that the genus is artificial and notably a recent molecular study suggested that Salpingella and Salpingacantha are likely synonyms. In this short communication we report on finding morphologically distinct loricas (containing ciliate cells) of Salpingacantha in single samples from stations in the North Pacific and Arctic Oceans in 2010, 2015 and 2016. We found up to 5 distinct Salpingacantha forms co-occurring, often with abundant Salpingella acuminata populations suggesting that some Salpingacantha species may be varieties of Salpingella acuminata. While we lack genetic data needed for definitive proof of polymorphism, here we document remarkable gradual gradients in morphology suggestive of polymorphism.
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Species complex
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