Encysted Nassula

[jc maccagno]

Freshwater 40X,50X 100X objectives

[Wes]

What is that structure with the arrow pointing towards it?

[jc maccagno]

Hello

The arrow is pointing to the mouth which is supported by internally stiff rods (basket or cyrtos). This is retained in the cystic form.

Thanks for looking

John

[René]

Remarkable!

Thanks for showing, René

[Mitch640]

Excellent find. Do you know what made them encyst?

[RogelioMoreno]

Hi,

Very nice!

The mouth looks like one that I found some time ago:
http://www.photomacrography.net/forum/v ... ht=nassula


Rogelio

[jc maccagno]

Hello Mitch

Initially this water sample was rich in cyanobacteria including Ocillatoria and Spirulina and other smaller algae. Many Nassula were present in the initial sample. As the population of Ocillatoria and algae declined, so did the Nassula numbers. Eventually,( about 10 days later ) the cysts appeared. I assume that the triggering factor was a shortage of food.
From what I have read this seems to be the case.
Apparently adding cyanobacteria enriched water to this sample would cause the cysts to return to their ciliate form. Incidently the water sample still contained considerable Spirulina so perhaps it is not a food source for this ciliate.

Hope that this answers your question.

John

[Mitch640]

Thanks John. It goes a long way toward my understanding of Nassula in particular and amoeba in general. I had noticed that when my jars or aquarium started aging and the water would either lose it's oxygen or some other change happened, the amoeba of all kinds, especially the testate, would just disappear. I knew there was some trigger, but not what. A lack of food would account for it also, and now that you mention it, cyanobacteria would also be gone. I thought it was lack of oxygen or maybe increase of nitrates. I have not found cysts though.