Xanthidium impar in phase contrast

KDan · Post by **KDan** » Mon Feb 06, 2012 12:53 am

Xanthidium (Arthrodesmus) impar from Ireland. Obj. CZJ 25x, Phaco.

Cactusdave · Post by **Cactusdave** » Mon Feb 06, 2012 1:38 am

Good illustration of how useful phase contrast can be with the right subject. It tends to exist in the shadow of DIC, but really they are complementary techniques in what they can reveal in transparent subjects like protozoa and algae, and if you are lucky enough to have a phase setup it's always worthwhile giving it a try when you encounter a new subject.

Mitch640 · Post by **Mitch640** » Mon Feb 06, 2012 4:27 am

Very interesting. I make sure to look closely at all the phase images posted here, in the hopes of learning more.

I would love to know what the purple rays coming out of the center of the desmid are. Phase contrast does not seem to help with the particles inside the algae, but does show the bridge and the outline of the spikes better.

uaalgae · Post by **uaalgae** » Tue Feb 07, 2012 1:17 pm

I beleive the purple rays are musilage channels formed by pores in the wall of the desmid. The purple dye filled in these channels. Desmids with pores can glide or move by producing the musilage at either end or side of the cell. They use this musilage production similar to the method of movement by diatoms that have raphes.

Mitch640 · Post by **Mitch640** » Tue Feb 07, 2012 1:29 pm

Thanks for that information. I will be looking for it from now on.