Dileptus eating Tetrahymena (via)
Taxa present: 1. – Lobatula lobatula (Walker and Jacob); 2. – Elphidium macellum (Fichtel and Moll); 3. – Elphidium excavatum (Terquem); 4. – Elphidium advenum (Cushman); 5. – Elphidium complanatum (D’Orbigny); 6. – Elphidium crispum (Linné); 7. – Rosalina globularis D’Orbigny; 8. – Nonion commune (D’Orbigny); 9. – Aubignyna perlucida (Heron-Allen and Earland); 10. – Haynesina germanica (Ehrenberg); 11. – Ammonia beccarii tepida (Cushman); 12. – Ammonia beccarii beccarii (Linné); 13. – Asterigerinata mamilla (Williamson); 14. – Turrispirillina sp.; 15. – Spirillina vivipara Ehrenberg; 16. – Trichohyalus aguayoi (Bermúdez). Umbilical view; 17. – Trichohyalus aguayoi (Bermúdez). Spiral view; 18. – Trochammina inflata (Montagu); 19. – Miliolinella eburnea (D’Orbigny); 20. – Quinqueloculina vulgaris D’Orbigny; 21. – Cornuspira involvens (Reuss); 22. – Miliolinella circularis (Bornemann).
Hair and there
Ciliated protozoa, like these captured by Dylan Burnette of the National Institute of Child Health and Human Development using a confocal microscope (magnified 1,700X), are a diverse group of complex, single-celled organisms characterized by superficial hair-like organelles that they undulate to move themselves along. (Other motile protists have tails or false feet.)
Protozoa are abundant and common everywhere, found in ponds, lakes, rivers, oceans, soils and inside the human body. In the last case, that can be bad news since some species are parasitical and cause disease. Malaria, giardiasis, Leishmaniasis and dysentery are all examples of diseases involving protozoa, often transmitted to humans by the bite of a parasite-carrying insect.
Ciliates are frequently used to study basic mechanisms in evolution because they replicate both asexually and through sexual reproduction.
Asexual reproduction occurs by binary fission: The micronucleus undergoes mitosis and the macronucleus elongates and splits in half. The cell then divides in two. Both new cells have a copy of the micronucleus and macronucleus.
In sexual reproduction, genetic material is exchanged, called conjugation, between two organisms of different mating types. (Mating types is akin to gender but, in the case of ciliates, the number of mating types exceeds two.) Conjugation occurs when food is rare. Two cells form a bridge between their cytoplasms, their micronuclei undergo meiosis, macronuclei disappear and the haploid micronuclei are exchanged over the bridge. The cells then separate, form new macronuclei from their micronuclei, and divide to create four new cells.
Pretty complicated for a critter measuring less than two millimeters (the thickness of a nickel) in length.
Saccinobaculus sp. and Barbulanympha sp. (via)
The oxymonad protist Saccinobaculus (foreground, at about 12 microns in diameter) orbiting the much larger parabasalid protist Barbulanympha (background, at about 100 microns in diameter), which is covered in a dense monolayer of rod-shaped symbiotic bacteria. From the hindgut of the wood-feeding roach Cryptocercus. Images by Kevin J. Carpenter. (More)
Dr Paul Hargreaves and Faye Darling call this electron microscopic image of dinoflagellates ‘MiroMira2’, but we think it looks like a couple of muffins. (More)
Ceratochoris horrida (via)
Stentor sp. (via)
A gregarine (via)
Credit: James Marden. The parasite that causes metabolic disorders in dragonflies, as it appears under an electron microscope at 100-micron scale. Known as gregarines, the parasite belongs to Apicomplexa, a group of microorganisms including protozoa that cause diseases like malaria and cryptosporidiosis. (More)
from Fan et al. 2011. Two novel marine Frontonia species, Frontonia mengi spec. nov. and Frontonia magna spec. nov. (Protozoa; Ciliophora), with notes on their phylogeny based on small-subunit rRNA gene sequence data. Int. J. Syst. Evol. Microbiol. 61(6):1476-1486.