Paulinella, mixotrophic amoebe

[Rene]

This is one of those crazy things: an amoebe but also able to grow on sunlight. Professionally, very boringly called mixotrophic, but nevertheless intriguing.



It's called Paulinella chromatophora, it has 2 chromophores (duh) called cyanelles because it's not really a chloroplast, and it's not even known whether it is acually an organelle or a symbiontic cyanobacteria. But maybe that's trivial, in any case it is related to Synechococcus, an omnipresent cyanobacterium.

The wall of this amoeboid organism is typically banded with overlapping scales, well visible with an oil immersion lens:



Sample derived from a freshwater lake in the north of the Netherlands, size 25um. Images uploaded at http://www.photomacrography.net

Best wishes, René

[Ernst Hippe]

Hallo René,
danke für die Präsentation des seltenen Fundes! Für mich ein Wiedersehen nach sehr vielen Jahren - nur ein Mal.

[7an]

Hi there,

that's kinda fascinating... picture two looks like the autofluorescence of chlorophyll?
According to Takuro Nakayama et al. 2009, P. chromatophora is currently acqiuiring a cyanobacterial endosymbiont. At least one gene has already been transferred from the chromophore genome to the nuclear genome.
So the chromatophore is on its way of beeing integrated within the host cell.

Never heard about that until now, thanks for the pictures and the new stuff to read through!


Ref:
Another acquisition of a primary photosynthetic organelle is underway in Paulinella chromatophora., Curr Biol. 2009 Apr 14;19(7):R284-5., Nakayama T, Ishida K.

[Ronald Schulte]

Rene,

Nice pictures; didn't you had a Leitz Orthoplan to? I can't remember me!

Also that link to the photowebsite is a recommended one, thanks.

Greetings Ronald

[Rene]

Thanks guys, I forgot to add the top right photo is autofluorescence with a 365nm UV led and longpass barrier (>420nm). Unfortunately I haven't got a specific filterblock for cyanofluorescence (yet), but I am working on that. Images are made on an Oly inverted (IMT2) with 20x/0.7 and 60x/1.4 lenses in a 2ml sedimentation chamber. It seems the critter is rare, an inverted microscope makes it a lot easier to find.

BTW, another Paulinella species I do find regularly in marine samples is Paulinella ovalis. It is a lot smaller and has the same type of lorica with scales.



It was originally described as a chrysophyte flagellate by Wulff (as Calycomonas), it has only recently been redescribed as an amoebe. What appeared to be a flagellum sticking out of the lorica actually was a very thin pseudopodium. I have seen similar thin pseudopodial threads from this Paulinella chromatophora, but they are hard to capture on an image. You can see bits on the first lower image at high mag.

Best wishes, René

BTW, found a wonderful article by Michael Melkonian on the original description by Lauterborn: http://dblab.rutgers.edu/paulinella/pdfs/16171191.pdf