a kind of Amoeba?

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Aenima
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a kind of Amoeba?

#1 Post by Aenima » Thu Sep 06, 2018 12:38 am

Hi,

Wondering what this type of amoeba is, if it IS an amoeba?

I am seeing a lot of them, mostly in my moss and rainwater samples - when I google 'amoeba' I can only find images of the standard shapeless type that seems made of oozing liquid, but these seem to be more solid - I know they're not, but whenever I see one its always round. Small pseudopods do branch off but they are tiny and branch off the main body rather than the whole amoeba changing shape to form branches. I caught one trying to surround a long bit of vegetation once, and it did seem to briefly lose it's shape but generally they all look like cookies - this is what I've taken to calling them 'cookie amoebas' as they all seem to look like nut or raisin cookies.


The one time I found something online that resembled these amoebas was a thing called 'Enta amoeba' but I think I read that these are always found internally as a parasite...

edit; they also seem to be larger than the 'oozing' type

Hoping someone can point me in the right direction in identifying them?

thanks in advance for any info :)

cookieamoabeweb.jpg
cookieamoabeweb.jpg (470.27 KiB) Viewed 2890 times

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75RR
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Re: a kind of Amoeba?

#2 Post by 75RR » Thu Sep 06, 2018 6:26 am

I have not come across any 'cookie' amoeba as yet - looks interesting!
A video would be nice to see if you get the chance.
In the meantime have a look around this site:

https://www.arcella.nl/amoebozoa
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Aenima
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Re: a kind of Amoeba?

#3 Post by Aenima » Thu Sep 06, 2018 6:43 pm

thanks 75RR, i am forging ahead with that link, although it's unfamiliar territory for me - i don't fully understand a lot of the technical terms, so have to go with the images and hope to stumble onto a match visually. :)


I will sort out some video footage once i get onto my laptop - might be something in there that helps :P

Bruce Taylor
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Re: a kind of Amoeba?

#4 Post by Bruce Taylor » Sat Sep 08, 2018 1:56 pm

It is certainly an "amoeba" but it is not an Amoeba (i.e. not a member of the rather minor genus Amoeba). ;)

The word "amoeba" (lower-case) is commonly applied to any type of cell that can produce pseudopods, and your critter is certainly one of those. However, amoeboid cells are found all over the eukaryotic tree of life, so this does not narrow down the possibilities very much.

The first step is to get good look at those pseudopods. If they are blunt-ended and somewhat tubular, or broad and flat, your organism probably falls with the supergroup Amoebozoa. If they are thin and threadlike, or taper to a sharp point (as I suspect they will be), there are other possibilities. Most "filose" amoebae fall within the supergroup Rhizaria. However, the pseudopods of nucleariids (Nuclearia, more closely related to fungi than to the Rhizaria) are also fine and pointed (i.e. "filose"), and can radiate from a very compact, round cell.

If you have any pics including pseudopods, that would be a good start.

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cuxlander
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Re: a kind of Amoeba?

#5 Post by cuxlander » Sat Sep 08, 2018 6:23 pm

Hello Aenima,
I believe it is Zonomyxa violacea or an Amphizonella species.
Cheers,
Hans


Added: Se my http://hans-rothauscher.de/testaceen/pyxidicula.htm

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Aenima
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Re: a kind of Amoeba?

#6 Post by Aenima » Sat Sep 08, 2018 8:00 pm

wow, great help - many thanks Bruce, for the knowledgeable info and cuxlander your suggestion does look like it matches visually, - i quickly realised i was rather out of my depth trying to identify this amoeba myself - especially just using a google search of 'amoeba' :P so it's nice to be able to make some progress.

I will still find and post a video, hopefully for confirmation if possible, but it might not be the best footage.

edit: also i had no idea that it could be a testate variety - i was searching through the naked amoeba lists on the website :p apparently testate amoebas can have a thin transparent 'house' and appear to be naked to the inexperienced eye - good to know, thank you!

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Aenima
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Re: a kind of Amoeba? (vid added)

#7 Post by Aenima » Sat Sep 08, 2018 11:12 pm

here is a (rather sketchy) video showing one of these 'cookie amoeba's with extended pseudopods - unfortunately the view is jiggled around quite a lot due to a curious rotifer butting in and paying very close attention to the amoeba :)
apologies for the lighting and other issues - i was adjusting the GUF and other stuff during recording thinking i could edit later but never got around to it. :P





https://youtu.be/lCmhmxlFDxc

Bruce Taylor
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Re: a kind of Amoeba?

#8 Post by Bruce Taylor » Wed Sep 12, 2018 11:10 am

Helpful video. :) The pseudopods are lobose (somewhat tubular, blunt-ended), and it's clearly an amoebozoan. Cuxlander's suggestion seems like a very good one! Ferry's site has a section on microcoryciids (which seem to be found in moss, and include some purplish species): https://www.arcella.nl/microcoryciidae

Flexible tests are found in quite a few species. Indeed, some classically "naked" amoebae have coatings of rigid scales that can't be seen in the light microscope. For instance, see the marvellous SEM images Eckhard Voelcker and Steffen Clauß have produced of the "not-so-naked" amoeba Korotnevella: http://penard.de/Amoebozoa/Discosea/Flabellinia/

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Aenima
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Re: a kind of Amoeba?

#9 Post by Aenima » Wed Sep 12, 2018 10:14 pm

Bruce Taylor wrote:Helpful video. :) The pseudopods are lobose (somewhat tubular, blunt-ended), and it's clearly an amoebozoan. Cuxlander's suggestion seems like a very good one! Ferry's site has a section on microcoryciids (which seem to be found in moss, and include some purplish species): https://www.arcella.nl/microcoryciidae

Flexible tests are found in quite a few species. Indeed, some classically "naked" amoebae have coatings of rigid scales that can't be seen in the light microscope. For instance, see the marvellous SEM images Eckhard Voelcker and Steffen Clauß have produced of the "not-so-naked" amoeba Korotnevella: http://penard.de/Amoebozoa/Discosea/Flabellinia/

Excellent info - thank you, Cuxlander and Bruce Taylor :)


I have to say that link 75RR provided was a huge eye-opener - i had no idea amoebas were so varied in type/shape and with so many different species. It has put me back in amoeba mode - returning to the pond, and including chunks of nearby moss along with a scoop of pondwater - and have been scanning for amoebas. This time with a better idea of what to look for.
Found a large-ish species, quite chunky but still fluid in shape and moving around a lot more than the cookie amoebas. No pink colouring either and the whole body was involved in making pseudopods.
Still haven't caught any eating yet - except for the failed attempts from the 'cookie' amoeba to surround a long stick of vegetation, over the course of 2 hours it tried 3 times - a case of 'eyes bigger than it's ... vacuole?' :P

But yeah, perfect opportunity to use my 'mix n'match' phase contrast - amoebas seem to pop right out with it. :)

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Re: a kind of Amoeba?

#10 Post by SunshineLW » Mon Sep 17, 2018 1:56 am

Sweet images and video. Amazing technique.

You are correct about the Entamoeba being a parasite. Entamoeba is a genus of parasitic protozoa that can be either non-pathogenic or pathogenic. Pathogenic forms may damage the host's intestines and liver, often causing diarrhea.

Entamoeba histolytica trophozoite in a fecal smear, 1,000x magnification, 10 μm scale bar, stack of 15 exposures:
Entamoeba histolytica trophozoites (vegetative form) (15 stack) (Logo).jpg
Entamoeba histolytica trophozoites (vegetative form) (15 stack) (Logo).jpg (159.46 KiB) Viewed 2492 times
Entamoeba histolytica cyst in a fecal smear, trichrome stain, 1,000x magnification, 10 μm scale bar, stack of 3 exposures:
Entamoeba histolytica trichrome stain (3 stack) (Logo).jpg
Entamoeba histolytica trichrome stain (3 stack) (Logo).jpg (134.58 KiB) Viewed 2492 times
Entamoeba histolytica in liver abscess, cross-section, 1,000x magnification, 10 μm scale bar, stack of 3 exposures:
Entamoeba histolytica cross-section of liver abscess (3 stack) (Logo).jpg
Entamoeba histolytica cross-section of liver abscess (3 stack) (Logo).jpg (181.86 KiB) Viewed 2492 times
More images of Entamoeba on The Monster Hunter's Guide to Veterinary Parasitology: http://www.veterinaryparasitology.com/entamoeba.html

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Aenima
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Re: a kind of Amoeba?

#11 Post by Aenima » Wed Sep 19, 2018 9:10 pm

thanks SunshineLW - great links and info.

Yeah, I wasn't really sure about the entamoeba - it was just the only picture that I could find via basic google search - the dark round bits seemed similar, but everything else was wrong. :)

Once I had more to go by, I found many similar images and could more confidently ID the general type of amoeba I photographed. :)


thanks again to those who commented on the thread and provided info :)

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