Arcella dentata

[Francisco]

Arcella dentata, a nice testate amoeba

[Bruce Taylor]

Really nice video, Francisco! This species is now in the genus Galeripora.

[jackieone]

What a delight! Thanks for sharing this!

[charlie g]

Thank you francisco for sharing this testate amoeba encounter.

I wonder about how heavily colonized your amoebas test seems to be...almost 'covered with fir'. Did you sense any interior cell activity, any contractile vacuoles enlarging/ then rapidly 'shrinking', any indications this

testate amoeba was alive when encountered?

I encountered a similar testate amoeba in our north temperate zone freshwaters..the individual I encountered manifested active vacuoles, and the test was not thickly colonized as your encountered testate amoba.

This for me is of interest..do freshwater testate amobae keep/ cleanse their test from being heavily colonized while alive? Over the years, I have never encountered living testate amoebae with their 'test/shells'

colonized . I never encountered empty amoebae tests/shells colonized. Your post has me thoughtful about : are amoebae tests/shells colonized in live amoebae, or in dead amoebae?

Thank you, francisco for this shared encounter, charlie guevara/finger lakes/US enclosed a freshwater living testate amoeba similar to your encountered specimen.

[Bruce Taylor]

the individual I encountered manifested active vacuoles,

Hi Charlie! Arcellid amoebae have the ability to form pockets of gas, which they use to right themselves when inverted or to relocate themselves by flotation. Here's a short paper describing the behaviour in Galeripora discoides (then known as Arcella discoides): https://onlinelibrary.wiley.com/doi/epd ... .tb04441.x

I have never encountered living testate amoebae with their 'test/shells' colonized

There are parasitic rotifers that will invade the shells of living lobose testate amoebae. Here's a video of some I encountered in the shell of Galeripora artocrea (previously Arcella artocrea): https://www.youtube.com/watch?v=JLG8j0jNgq4&t=22s I've also found them living in the shells of Netzelia tuberculata (previously Difflugia tuberculata): https://www.youtube.com/watch?app=desktop&v=Tuf0lViRWh8 I found it interesting to see multicellular animals parasitizing single-celled organisms.

[Francisco]

Really nice video, Francisco! This species is now in the genus Galeripora.

Thanks Bruce for the information.

[Francisco]

What a delight! Thanks for sharing this!

Thanks.

[Francisco]

Thanks Charlie.
Yes, Arcella was alive.
Greetings

[charlie g]

Thanks again, francisco, for sharing this protist image capture. Thanks too bruce (many thanks for numerous thoughts you post into threads)..I see your cited examples of colonized amoebae tests/ shells are all

instances of endosymbionts harboring 'inside amoebae tests'..not epibionts attached to the tests exterior surface, not attached to interior test surface.

I notice in all your links to organisms active 'inside amoebae tests', none are attached to said test, bruce. The tests themselves are 'squeeky clean'..no exterior colonies of epibionts. as is the test francisco shares.

I noted to francisco and group, how I never encountered an amobae test with such' a dense/ thick fir'..test inhabited by a live amoeba..or even an 'empty amoeba test'. Francisco's amoeba test even has a circle of diatoms adherent on it!

This really caught my curiosity, francisco, again, thank you. We share our bodies with endosymbionts, epibionts, commensal communities,symbiotic communities, mutualistic relationships, parasitic relationships, and then that huge collection of essential ( for us)

of 'microbiome communities'. So too do testate amoebae participate in webs of such relationships. Just recently we have discovered it is the microbiome community in our gut tracts..which gives our 'pee' it's yellow color. We knew the blood

breakdown products are the start materials..but we thought ( incorrectly) that our metabolic machinery produced the yellow color..not so, our gut microbiome produces that color.



I'm really now curious about amoeba tests manifesting 'thick fir', and diatoms..as does fracisco's amoeba test. charlie guevara

[Bruce Taylor]

I noted to francisco and group, how I never encountered an amobae test with such' a dense/ thick fir'

You've raised an interesting point, Charlie. In more than 10 years of cell-picking I must have looked at many thousands of individual arcellinids and I have to say...the shells of living specimens are usually quite clean, without "hitchhikers." I don't think I've ever seen one with an attached peritrich or suctorian, for instance. Shells of dead amoebae plucked from sediments are often encrusted with bacterial filaments, etc. (some more than others...old Centropyxis shells can be quite fuzzy!). When I go back to the bogs and fens this spring I'll remember to pay more attention to ectocommensals (or their absence, as the case may be!).