Green Amoeba (now known to be a Euglena species)

[Bruce Williams]

Hi Folks,

Thank you for the warm welcome and encouraging words from all those who posted a reply to my last posting. (Hi Bernhard, good to see a familiar face - Bruce)

These pics are a bit different to my last posting. The images are cropped from original size stills captured from a video take with the Olympus SP-350 at 640X480. I used the Swift 200X achro objective with full 3X optical zoom on the camera (microscope Carton VSHLB-4). If anyone is interested I have uploaded the video to Google Video at:

http://video.google.co.uk/videoplay?doc ... 7&hl=en-GB

If you have not used the Google Video site before you can select the desired viewing size at bottom right of the video window. Obviously "original size" gives the best resolution although double size is ok if you find the original 320X240 video too small. I would love to upload to streaming video at the original 640X480 resolution if anyone knows where/how I can do that. So far I have tried Yahoo Video, Blip.tv and YouTube with similar results to Google Video.

The water is the same sample as my Stentor pics - from Stockgrove Country Park, Buckinghamshire. I would really appreciate identification if known. Am I right in thinking that the green colour is from the food ingested by the amoeba (Euglena)? The animal is moving right to left (although I guess that's obvious from the red eye spot). I think that with amoebae in particular the video medium really does add that extra dimension of understanding needed to appreciate the elegant flowing motion of the cytoplasm. Quite fascinating to watch.



Regards,
Bruce

[Thomas Ashcraft]

I might be wrong but I think that is some sort of Euglena in a motion that is termed "metaboly".

Tom

[Bruce Williams]

Hi Tom,

A quick search on the web proved you to be spot on. See:

http://silicasecchidisk.conncoll.edu/Lu ... _Main.html

Thanks for setting me straight on this one Tom. Boy this is an interesting hobby!

Regards,
bruce

[bernhardinho]

Boy this is an interesting hobby!

You bet, Bruce!!!

Now that you found that link, you know it already. It's a Euglena and the green chloroplasts haven't got anything to do with food intake, but show the result of a long evolutionary history. Google for "endosymbiont theory" and you'll find it even more fascinating.

See you

Bernhard

[beetleman]

You learn a new word here almost every day "metaboly" I think I move that way sometimes when I get out of bed in the morning Thank you Bruce for posting these great pictures and thank you Thomas for the info and the new word. I had no Idea that chloroplasts and mitochondria were being thought as "Endosymbionts". Being a theory means they are really not sure on that Bernhard right ??

[Ken Ramos]

Quite an interesting post here Bruce, great video with photographs to match. Keep it up!

[rjlittlefield]

Being a theory means they are really not sure...right ??

Yep, that's the usage here. It's an idea that could be either right or wrong, and the evidence either way is not overwhelming yet.

There's a different usage of that word "theory" that's also common in science. A world-class computational chemist once explained it to me this way: "When we say 'theory', what we really mean is some approximate model that's simple enough to be worked with, and accurate enough to be useful. It's not a question of absolutes. We know our theories are 'wrong' as in 'not exact' -- we just hope they're 'right enough'."

It's a very useful distinction. When "theory" means "model", some common phrases suddenly make a lot more sense -- like "theory of operation" in an electronic service manual, or "Bronsted-Lowry theory of acids and bases" in a chemistry textbook, or Mendel's "theory of inheritance" in genetics, or "thin lens theory of optics" in photography. They're not supposed to be either "right" or "wrong", they're just approximate models that are simple enough to work with and match pretty well to what the world actually does.

--Rik

PS. Bruce, those are nice videos! I was especially intrigued to see the little linear, slightly spiral, bacteria(?) that are swimming around and periodically seem to get stuck on the side of the Euglena. There's one visible on the upper edge of the Euglena in the lower right picture. In the movie there's another one, about twice as long, that gets stuck a short distance away, just before fade-to-black at the end.

[bernhardinho]

Hi folks,

well, Rik gave some interesting thoughts on the issue. I am certainly not a scientist and I won't make any comments on right or wrong of any theory. When I think of the "theories" in modern physics, what can we be sure about at all on this planet? ( I'm reading a book on quantum theory right now, some odd things to swallow there!!) But isn't it an interesting fact that mitochondria do feature their own DNA!!??

The bacteria, Rik, are most likely some sort of Spirillium spec.

Bernhard

[rjlittlefield]

Bernhard,

You got me thinking about quantum theory, but what I wrote was so off-topic that I moved it to the general discussion forum instead of posting here. See this posting if you're interested.

Now mitochondrial DNA, that's a worthy topic! Another time, perhaps...

--Rik

[Bruce Williams]

Thanks to all for feedback and thought provoking discussion.

I always feel a flush of embarrassment when the subject of mtDNA comes up. Back in the early 90's I had a very public arguement where I found myself (wrongly) heatedly disputing the fact that mtDNA is inherited solely through the maternal line. Later that day (still certain I was right) I spent some time researching the subject only to discover to my horror that my adversary was right and I was wrong. Naturally I had to eat humble pie the next time we met.

The one positive I got from the experience was: "No matter how 100% dead certain you are about a thing, there's always a good chance that you could be wrong!".

...and Bernhard - Endosymbiont Theory - yet again I find myself amazed at how I could have remained so completely ignorant about a concept that is so fundamental to the origins of life - thanks for the the pointer - I'm still reading.

Bruce