Termite Symbiots

[Martin Coleman]

USA

Symbiots are protists which live in the gut of termites and without which the termite would starve to death. Termites can't digest cellulose and so are dependent upon the organisms in their intestines to digest wood particles and transform them into sugars and starches which the termites can metabolize. These extraordinary creatures have not been thoroughly studied and there are still a significant number of undescribed species.
Here is a sampling with a few comments about some of their structure.

The organism above is Trichonympha campanula and is one of the more common and best studied denizens of the termite gut. It is clearly a complex micro-organism with long flagella covering most of the surface, a distinct nucleus, and a structure at the anterior end called the rostrum.Note the clear area at the posterior end. This is of special importance, because it is here that feeding takes place. If we look at the previous image which shows the detail of the rostrum, there is nothing there that suggests a cytosome (mouth). Trichonympha feeds by engulfing wood particles through this clear space by forming structures rather like pseudopodia. Flagellaare present extending down and they are, in fact, "anchored" higher up on the membrane.The yellowish particles in the lower half of the organism are wood particles and are extremely numerous, packing up the entire lower half of the body.

This one is named Streblomastix strix and is very different from Trichonympha. Perhaps the most remarkable feature of Streblomastix is the extraordinarily long flagella. Below are two additional views.

In addition to the long flagella, the body is spirally striated and quite elastic and contractile as you can see when you compare with the other two.

Another intriguing symbiont has an undulating membrane and when active looks like a miniature chainsaw.

This is Trichomitopsis. Below is another view.

All of the larger flagellates which I examined appeared to have a striated membrane which is evident in both images. In the top image, you can see, on the right, some of the flagella which are distinctly shorter than in the other two organisms we've considered.

This organism almost certainly belongs to the Hypermastigida given the exceptionally large number of flagella.

Notice that on this specimen, although the flagella are very numerous, they are considerably shorter than those in the other examples looked at.

This one appears to have groups of flagella which are arranged in tufts.
Here is a closer look at some of the features of Trichnympha.

Here there is a clear view of the ovoid macronucleus which is approximately in the center of the organism.

This image clearly shows the nucleus, the striated character of the membrane and the rostrum or "cap" at the anterior end.

Yet another view. Notice at the posterior end, to the left, there is clear space surrounding the "body".
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