General

Bacteria of the genus Holospora (H. elegans, arrows) colonize the micronucleus (MI) of the ciliate Paramecium caudatum (‘endonuclear symbionts’). The bacteria actively invade the ciliate and the nucleus and are also given to the daughter cell during division. Some bacteria are also released to the environment to infect new hosts. The macronucleus is also visible […]

Paramecium bursaria (Video) is a model ciliate in protist science that lives in symbiosis with algae (green). Here, we see the characteristic two contractile vacuoles with the collecting channels, the cell mouth (slit-like depression with many moving cilia in the middle of the cell) and the macronucleus (appears ellipsoidal in grey).

Individuals of Vorticella chlorellata posess a stalk with which they are attached to other plankton or debris. In this combination they are too large to be ingested by predators. The symbiotic algae (green) provide photosynthetic products to the ciliates and are able to synthesize UV sunscreen compounds (MAAs).

Pelagostrombidium fallax feeds on planktonic algae and digests everything but the chloroplast (=’stolen chloroplast’ or ‘kleptoplast’). From the kleptoplasts (photosynthesis), the ciliate receives additional nutrients.

Paradileptus elephantinus is a huge ciliate that even ingests rotifers (small metazoans).

Lagynus elegans prefers the oxygen-depleted zones in a lake.

Coleps hirtus viridis is a ciliate commonly found in lakes and ponds that receives nutrients from its algal symbionts (photosynthesis). Here we see the characteristic cortical plates.

Bursaridium sp. is a ciliate living in the plankton of alpine lakes above the treeline. Compared to other planktonic ciliates it is a relatively large species (ca. 150 x 120 µm). Bursaridium sp. feeds on algae that provide UV sunscreen compounds (MAAs) to the ciliate.