Voracious Soil Amoebae

Image gallery of amoebae with large appetites

By Paul James (UK)

 

I had assumed for many years that Amoebae fed exclusively on diatoms, bacteria, spores and cysts etc.. We have seen the food vacuoles frequently to support this either in the living state or by inspection of books on the matter. Recently, I was amazed to witness under the coverslip, about 20 soil amoeba engulfing more than seemed possible. They were in one way or another engulfing or injesting long bulky strands of algae, a surprising feat and feeding habit not known to me. At first I thought they were going through the motions of assessing the size of the 'prey' but soon realised as I viewed a few more that these were serious attempts to injest and digest the algae.

Whether this episodic event is actually caused through enforced conditions I cannot say, but I have not seen a spectacle like this since, and therefore wonder if circumstances that motivated these amoebae to feed like this have ceased to exist, which may change as warmer weather follows this spring?

The following images are typical of a series taken from samples of 'cultured' soil Amoebae which have been existing in jars for some years. Naturally I recorded many images and some are shown below that are proof of these amazing gastronomic events.

Here an amoeba has settled down to consume and digest the entire length.

Note lack of pseudopodia.

Later on the filament has been entirely injested
This individual seems content to digest a little at a time
Another example of a lengthy algal specimen nearing

digestive disintegration

Another starting the long process
Haematoccus pluvialis.....another large dish !
Nothing like starting in the middle.
Amoeba at full stretch. This is a single image from a series showing its attempt to injest the

algal filament which eventually failed and so the amoeba moved on.

Almost completely digested Haematococcus in amoeba on left and initial

breakdown of same in amoeba on right.

These images were captured using various illumination techniques such asbrightfield, phase contrast and COL, implemented at various times using the Zeiss Photomicroscope and Minolta F300 digital camera.


All comments welcome by the author Paul James

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