Arachnoidiscus

[emsiem]

I got this antique diatom slide few days ago. Nothing unusual, but nice.
Cleaned diatoms do not exhibit auto-fluorescence, but I wanted to try as some mountants do and it can have interesting effect.
So here, what I think is mountant fluorescing from channels in diatom structure.
Sorry, photos are not of superb quality. I just find it interesting.

Arachnoidiscus ehrenbergii diatom


Leitz NPL 16X 0.40 (crop)



Leitz PL Apo 40X 0.75
EPI Fluorescence

[René]

Quite amazing Nenad, the blobs on the edge suggest chloroplasts. So the mountant didn't penetrate all the internal structures. Did you heat up the slide?

Best wishes, René

[emsiem]

Thanks René.
Yes, chloroplast would emit red under this excitation so maybe this is the answer to my puzzle. But, surroundings where only mountant is also fluoresces red.
I didn't heat the slide.
In fact I have fresh anecdote about the slide. Yesterday I had some friends visit me and as they didn't look through scope since elementary school, I gave them to play a little bit with with my other scope (Leitz SM) and this slide. I was talking with one of them and heard "CRACK!". Other guy "focused" into this slide so much that it cracked in half (whole slide, not coverslip)! So photos I have are last :-)

Here is original (just little cropping on sides) without contrast correction so I thought it must be mountant, but you are probably right.