Bizarre Protozoan (Stentor) Disintegration
A stentor ciliate disintegrates right before your eyes. I was observing a large drop of pond water in a Petri dish on low power with a Zeiss 4x NA 0.14 Planapo and a projection eyepiece (10x), 1.6x multiplier on the trinocular head totalling 60x. *No coverslip* used. What I witnessed would certainly be bizarre to the layman but for scientists and experienced microscopists, this might not be that unusual a phenomenon. Camera used was a Sony A7III.
That said, it was certainly a remarkable spectacle for both layman and perhaps scientists alike, although more so for the former. Normally, a protozoan would burst if a coverslip was used - as the water droplet dries away, it exerts pressure on the cell. Or in another situation whereby a cell was pricked with a very fine needle. However, in this case, it was observed in a Petri dish with no pressure exerted on the animal. As none of the two factors occurred, the most likely reason(s) would be cytolysis among others, although I stand corrected being only an amateur naturalist.
According to a Wikipedia source:
Cytolysis, or osmotic lysis, occurs when a cell bursts due to an osmotic imbalance that has caused excess water to diffuse into the cell. Water can enter the cell by diffusion through the cell membrane or through selective membrane channels called aquaporins, which greatly facilitate the flow of water. It occurs in a hypotonic environment, where water moves into the cell by osmosis and causes its volume to increase to the point where the volume exceeds the membrane's capacity and the cell bursts. The presence of a cell wall prevents the membrane from bursting, so cytolysis only occurs in animal and protozoa cells which do not have cell walls.
The reverse process is plasmolysis. It occurs in a hypertonic environment, where water moves out of the cell.
Or another possible factor I found in a Google resources search (if there are factors not listed, please educate me): Contractile vacuole failure. “If there is too much water, the contractile vacuole works to pump out the water. This helps to protect the cell: if there is too much water in the cell, it will swell and swell until eventually it ruptures, destroying the cell.” “The point of the contractile vacuole is to pump water out of the cell through a process called osmoregulation, the regulation of osmotic pressure. It occurs in freshwater protists, but mainly in the kingdom Protista as a whole.” Source - study.com.
NOTE: After stentor imploded, a small portion of the cell fragment survives. Unfortunately, I lost track of the fragment remnant to see if it grew to a normal stentor. I come across at least one video in YouTube (Russian) that documented the same phenomenon.
Comments to Chew Yen Fook are welcomed.
Protozoan implodes and disintegrates. Dramatic footage captured. (1080P recommended).
Music credits: Royalty free music by Kevin Macleod. See YouTube video outside of embedded frame for details.
Published in the April 2019 edition of Micscape.
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