Mallomonas insignis

Images made through a microscope. All subject types.

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Charles Krebs
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Mallomonas insignis

Post by Charles Krebs »

Mallomonas insignis is a synurophyte alga. It is related to the chysophytes (like Dinobryon) but it is enclosed in a layer of siliceous scales. Very obvious are the brown/tan colored chlorophyll containing plastids.

I collected a fresh sample from my favorite (ice covered!) pond and found this species for the first time. It can look different depending on where the microscope is focused. The "inside" looks very much like a diatom. Around the cell is a "coat" of scales that reminded me of certain scaled amoeba tests. There was a single flagellum up front (not seen in these photos) and at the rear, a "tail" of scales. Interesting specimen.

In the last shot of these three I tried to get a close look at the scale "coat", and as you can see from the scale bar, we're dealing with some pretty small structures. Two "focus selections" are given to give a sense of the construction.



Image

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Cyclops
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Post by Cyclops »

Wow, some really neat images there! I got a long way to go before I can get them this good!
What objective/eyepiece combo were you using?
Canon 5D and 30D | Canon IXUS 265HS | Cosina 100mm f3.5 macro | EF 75-300 f4.5-5.6 USM III | EF 50 f1.8 II | Slik 88 tripod | Apex Practicioner monocular microscope

Ken Ramos
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Post by Ken Ramos »

Quite beautiful there Charlie :D , don't think I have ever ran across one of these. The cold weather undoubtedly will bring about some very interesting pond critters along with diatoms and various algae, since more sunlight is getting to the water now and the DO (dissolved oxygen) levels are coming up. Though most pond critters do not need a high oxygen content, they seem to be most prolific during the cooler or colder season. :)

rjlittlefield
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Post by rjlittlefield »

Wow! Yes indeed, that is some fine structure -- and beautifully captured as always! :D

But I'd have to admit that I don't really understand the construction. Does the shell have a single layer of scales that overlap like shingles? Or does it have multiple layers?

--Rik

Walter Piorkowski
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Post by Walter Piorkowski »

Excellant detail as always Charles. Providing the surface and side views are very helpfull. It's like I'm viewing with you at home.

And congrats on your winning images on the 2007 Nikon Small World calander. I recieved one the other day for having entered but alas was not chosen.

Walt

Bruce Williams
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Post by Bruce Williams »

Spectacular series of photos - so much structural beauty in such a tiny animal. Love the colours too - the silica scales look like matt glass crystal.

It would be interesting to see a brightfield photo for comparison.

Bruce

Bruce Williams
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Post by Bruce Williams »

...and yeah I know that my use of the term animal in my last posting is not exactly taxonomically correct :lol:

Charles Krebs
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Post by Charles Krebs »

Bruce... I did take a few with oblique brightfield. Unfortunately there was no A:B comparison... so don't put too much weight on this, but this might give you some idea compared to the 4-panel shot above (although I think the "situation" for the 4-panel images was better).

The scales on the subject are clear as glass, but oblique brightfield did a good job. Now that I have used DIC for about 8 months, I must say that my previous opinion that oblique brightfield is vastly underused and underrated is only reinforced. I would never say DIC isn't wonderful, but with some practice, oblique (and some other techniques like COL) can be used very effectively in many situations where DIC works well.

Image

Walt... Thanks!

Rik... it is a little difficult to visualize. Maybe I should go through all the shots to look for a better progression. I tried a 2 or 3 shot "stack" but wow, was that ever confusing! My impression was that is consisted of (at least) two interleaved layers of (roughly) diamond shaped scales. The first high mag image (upper) shows the layout pretty well. The second does get confusing since they are essentially clear and the edges are staggered and overlap.

beetleman
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Post by beetleman »

It is amazing what a little focusing can do to the structure & textures under the microscope. Wonderful little specimen & photos Charles :wink:
Take Nothing but Pictures--Leave Nothing but Footprints.
Doug Breda

Bruce Williams
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Post by Bruce Williams »

Thanks for posting the oblique brightfield image Charlie. I have to say it stacks up surprisingly well against the DIC images, particularly considering your comment about the relative shooting conditions. However I do take your point re. caution over placing too much relevance as not actually a true A:B comparison.

Anyway your results have encouraged me to read up and experiment with OB and I hope to be posting my first images fairly soon.

Bruce

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