Microworld

world of amoeboid organisms

Moist chamber preparations are well suited for studying Microgromia and related species. These small amoeboids often built their shell attached to the cover slip, which makes it an ideal position for observations with a 100X oil immersion objective. A moist chamber preparation is in fact a short culture, which can kept for several days in good conditions.
In September 2012 when I controlled some of my Microgromia-cultures, I saw one shell filled with two cells, obviously both cells had just divided.

Microgromia haeckeliana
This shell contains two cells. Shell = 11 µm. The same shell shortly after one cell left.

One hour later, when I looked again, the shell contained one cell. A quick search showed a naked flagellate at a distance of 870 µm. This flagellate seemed to be the daughter cell, a swarmer or zoospore. It was spherical and a flagellum was moving. I couldn’t see if it had one ore two flagellae.
Soon after I found it, the organism made a string of plasm, which became later the peduncle or pseudopodienstiel. It was a little broadened at the end. Probably that part was attached to the glass as an anchor point.

Microgromia haeckeliana
The yellow arrows point to the flagellum or flagellae.
Microgromia haeckeliana
The shell is ready. A flagellum is still visible inside the shell. Soon after it had disappeared. The cell forms branching and sometimes anastomosing granulopodia to catch bacteria.
Microgromia haeckeliana
The new shell two days later.
Microgromia haeckeliana
Two bacteria (arrows) are transported to the shell.
Microgromia haeckeliana
Ferry Siemensma, created March 3, 2019; last modified January 31, 2021
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