Mounting algae in fructose syrup

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Hobbyst46
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Mounting algae in fructose syrup

#1 Post by Hobbyst46 » Wed Dec 18, 2019 10:15 pm

I once thought about making semi-permanent slides (to last years, not decades) of algae without fixing and/or staining. Motivated by W. Dioni's published methods, I prepared fructose syrup from supermarket-grade fructose. About 80% (w/v) sugar, it is viscous and tends to include air bubbles and retain bubbles released among the plant leaves and stems. I fought bubbles with vacuum and other tricks, but when they are few in number, let them live. The syrup keeps very well at room temperature without mold or discoloration.

The following are images of three types of marine algae - two forms (A, B) of green filamentous and one (C) of green "leaves" from which green and red fibers tufts emerge. Sorry, no ID of any...
Alga A was mounted with glycerol and fructose syrup. Algae B and C - with syrup only. Algae samples were rinsed with distilled water, placed on the slide, excess water was removed with a piece of filter paper, covered with a slip, out-of-the-rims mountant was carefully removed with a wet Q-tip and finally, the sample was sealed with nail polish. Slides were stored in a box on a shelf at home, mostly at a temperature of 25-30C, and humidity 50-75%, without special precautions. The alga A slides are now 2.5 years old, the B and C slides are about two months old.

Brightfield images were obtained with a Plan 16X0.32 objective. All of them were taken with the same illumination and camera sensor ISO. All were referenced to the same white balance. In all images, the contrast and brightness were intensified by 50 and 70% respectively. They were also uniformly resized and cropped. No specific manipulation of colors was done. Each photo is a stack of 4-5 single images.

Unfortunately, background brightness is not uniform across the FOV, because of incompletely aligned somewhat illumination. Yet, the main point is how the mountant preformed. It would have been better to photograph the fresh algae in water, prior to mounting, as a reference of the colors, cell structure, cell size etc, for the future, but I failed to do so in time...; I also note that the syrup has an osmotic pressure, that in principle might affect plant cells some; nevertheless, the present images, at least, suggest the potential of fructose syrup to preserve alga pigments.

As always, comments are welcome.
Attachments
green marine alga A, 2.5 yrs old slides. Left- glycerol, right - fructose syrup.jpg
green marine alga A, 2.5 yrs old slides. Left- glycerol, right - fructose syrup.jpg (137.74 KiB) Viewed 2714 times
green marine alga B, 2months old slide. Fructose syrup.jpg
green marine alga B, 2months old slide. Fructose syrup.jpg (124.81 KiB) Viewed 2714 times
green leaf +green fibers+red fibers marine alga C, 2months old slide. Fructose syrup .jpg
green leaf +green fibers+red fibers marine alga C, 2months old slide. Fructose syrup .jpg (150.01 KiB) Viewed 2714 times
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

MicroBob
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Re: Mounting algae in fructose syrup

#2 Post by MicroBob » Thu Dec 19, 2019 9:13 pm

That looks pretty good! Did you use a fixative before mounting?
AS far as I know the complete identification of fibrous algae is quite difficult, perhaps not possible after preparation.
I recently came to algae "permenanent" mounts, maybe the decription gives a hint on the preparation method.

Bob

Hobbyst46
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Joined: Mon Aug 21, 2017 9:02 pm

Re: Mounting algae in fructose syrup

#3 Post by Hobbyst46 » Fri Dec 20, 2019 7:49 am

Thanks Bob,
No fixing. Freshly collected algae were rinsed with DW then mounted as described.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

Dave S
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Re: Mounting algae in fructose syrup

#4 Post by Dave S » Fri Dec 20, 2019 4:48 pm

Very interesting, thanks for posting.
Suffolk, UK

Brunel SP100 (with 4x, 10x, 40x,60x, and 100x (oil) plan objectives), and Canon EOS 4000d Camera (microscopy use only)

pigboy1537
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Joined: Sun Dec 29, 2019 6:14 am

Re: Mounting algae in fructose syrup

#5 Post by pigboy1537 » Thu Jan 30, 2020 4:58 am

I'm impressed with the results of the syrup. Even after a long time, it still looks good.

Hobbyst46
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Joined: Mon Aug 21, 2017 9:02 pm

Re: Mounting algae in fructose syrup

#6 Post by Hobbyst46 » Thu Jan 30, 2020 7:42 am

Thanks Pigboy.

It seems that the syrup preserves the chlorophylls for a long time. For that alga, it seemed to preserve the cell structure quite well.
I am not sure by how much it it effective for other plants. I recently tried the same with moss "leaves". It appears that cell structure was changed, partially destroyed, although the green color remained. Maybe chloroplasts were merged into larger bodies. When time permits I will post some results.
An intuitive, crude and "hand-waving" explanation is that the marine alga cells tolerate osmotic pressure differences better than moss leaves, which grow in a freshwater zone.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

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