Am I doing something wrong?

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malsi
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Joined: Mon Oct 21, 2019 10:56 pm

Am I doing something wrong?

#1 Post by malsi » Mon Oct 21, 2019 11:24 pm

So I just got a pretty nice Microscope (nice by my standards), and It's capable of seeing the very shape of blood cells pretty clearly. Thing is, I took a blood sample, samples from the inside of my mouth, nose, and ears, and such, but expected to find MANY bacteria. When you look at "germ" warning images, things like phones and tv remotes are ridden with bacteria. Of course, I know those are dramatizations, but shouldn't I be able to swab my phone and see at least 5 or so bacteria per slide? I'm getting almost no bacteria, no fungus, almost nothing at all after 15 slides. Are those commercials and images really GROSS exaggerations or am I cleaner than the average person? What has me worried I'm doing something wrong is, if i swab the inside of my mouth, I feel like I should see some living things in there. I'm told the mouth is a very disgusting place. At best I find a few of what i think are skin cells, but nothing else besides globs of things that seem to be too thick to see through. I assume those are clumps of skin.

I didnt even think the rain water from my gutters would be pretty clear, but they seem to be clear too. Ofc, I got a 7ppm water clarity from it, so I guess its not as dirty as I thought.

Before I make a trip to the creak just for some action, am I doing something wrong first? Should I be seeing bacteria/fungi/ anything in my bodily samples often? Especially blood. I figured the body is constantly fighting bacteria every second, but then again perhaps thats why i dont find any/much, maybe they're being destroyed too quickly. But surely I thought I'd find some gross things in my mouth. I can only seem to find water droplets and skin. =/

My equip is an OMAX and can go 4x/10x/40x/100x and my lenses are 10x and 20x So that should equate to 40x/80x/100x/200x/400x/800x/1000x/2000x unless i'm just an absolute moron and really don't understand anything at all.

P.s. im an absolute noob. I apologize in advance.

PeteM
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Re: Am I doing something wrong?

#2 Post by PeteM » Mon Oct 21, 2019 11:37 pm

I'd head down to the creek and get some mucky samples to view.

Bacteria are typically very small, and often transparent. They're hard to see.

You should be able to check some cheek cells from inside your mouth and swab them on a slide, with a cover slip over. Helps if you have polarizers (usually easy to add) to get a bit more contrast. Phase contrast even better.

Rain water is a kissing cousin to distilled water -- so what little is there or acquired on the way to the ground is also likely to be hard to see.

malsi
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Re: Am I doing something wrong?

#3 Post by malsi » Mon Oct 21, 2019 11:47 pm

When you say they are hard to see, how should I aid myself in seeing them? I've noticed pulling the light farther away from the stage helps to see detail. Should I keep the light here, or will they not appear this way? Also, the common bacteria, is it smaller or larger than a blood cell? Under my understanding, they're about 1/4th the size. But can be larger. Though I'm not sure what I'm expecting to see in a common household situation. I've probably discarded slides with them on there not knowing what I was looking for.

can you clarify, should there be bacteria from a cheek swab? Just hard to see?

wstenberg
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Re: Am I doing something wrong?

#4 Post by wstenberg » Tue Oct 22, 2019 12:08 am

Regarding cheek swabs...
Certainly there are bacteria on the surface of the cheek, but this is not a good place to go hunting for them. The epithelial lining of the cheek is constantly shedding. This prevents bacteria from adhering. Some bacteria have methods of attaching, but this is not a hospitable environment for bacteria colonization under normal circumstances. The cheek is an area that is trying to prevent bacterial infection- a line of defense. The best place to collect oral bacteria is on the teeth, around the gumline. You can use a toothpick and remove accumulated debris from along the gingival margin, then throw that toothpick away. With a clean toothpick carefully trace along the edge of the gums. You should be able to pick up a good quality of oral bacteria (it will look like a tiny white speck). Put this into a drop of water on a microscope slide. Use a cover slip. You should be able to see many bacteria. The most common cocci will be much smaller than the blood cells, maybe 30 times smaller. They are tiny. There should also be some motile rods which are a little larger. Also spirochetes which are long, thin and spiral. You will probably need to use your high power objective and oil immersion.

None of these will be easy to see with brightfield illumination. The typical way to examine these is with phase contrast or darkfield. If you use either of those methods, you can see them moving and living. You might even see an oral amoeba!

Your other option is to stain them. This process will kill them. The good news is that they will stain easily with many common stains.
William
Dallas, Texas

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MicroBob
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Re: Am I doing something wrong?

#5 Post by MicroBob » Tue Oct 22, 2019 8:21 am

Bacteria are about 1µm in diameter. The resolution of a light microscope with oil immersion objective is about 20µm. This means that you can resolve the bacterium and roughly see it's shape (. or - or ~) but not much more. To see it you have to adjust your condenser for maximum resolution - this is close to the top. Do you have an oil immersion objective? To get better contrast it will help to stain bacteria. On a stained slide you can see them with the 40:1 objective as little cloured dots.
Much work with bacteria is done by growing them on agar plated to have more material to observe. The light microscope alone can't tell too much about bacteria. It is the preparation and staining that leads to more information. Bacteria are a better subject for the professional than for the interested hobbyist.

Bob

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75RR
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Re: Am I doing something wrong?

#6 Post by 75RR » Tue Oct 22, 2019 9:52 am

.
As has been mentioned, within amateur microscopy, bacteria are not a popular subject.

This is not just because they are barely visible and so little can be distinguished apart from their shape, which is of little help in identification,

but also because there is so much more out there (or should that be in there) to see.

There can be a whole world in a drop of water – rich and varied and full of colourful life that can be seen in detail with 10x, 20x and 40x objectives.

There are also plants to be examined and chemicals to view in polarised light.

If on the other hand what you are interested in is self-diagnosis of health issues, then you should know that is not an advisable course of action and that this is not the forum for such activities.
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apochronaut
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Re: Am I doing something wrong?

#7 Post by apochronaut » Tue Oct 22, 2019 1:15 pm

MicroBob wrote:
Tue Oct 22, 2019 8:21 am
Bacteria are about 1µm in diameter. The resolution of a light microscope with oil immersion objective is about 20µm. This means that you can resolve the bacterium and roughly see it's shape (. or - or ~) but not much more. To see it you have to adjust your condenser for maximum resolution - this is close to the top. Do you have an oil immersion objective? To get better contrast it will help to stain bacteria. On a stained slide you can see them with the 40:1 objective as little cloured dots.
Much work with bacteria is done by growing them on agar plated to have more material to observe. The light microscope alone can't tell too much about bacteria. It is the preparation and staining that leads to more information. Bacteria are a better subject for the professional than for the interested hobbyist.

Bob
check your arithmetic, there Bob.

MicroBob
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Re: Am I doing something wrong?

#8 Post by MicroBob » Tue Oct 22, 2019 2:34 pm

Hi Phil,
thank you for pointing this out: The resolution is about 0,2µm, not 20µm! So the bacterium looks roughly as if seen an a 5x5 pixel matrix.

Bob
apochronaut wrote:
Tue Oct 22, 2019 1:15 pm
MicroBob wrote:
Tue Oct 22, 2019 8:21 am
Bacteria are about 1µm in diameter. The resolution of a light microscope with oil immersion objective is about 20µm. This means that you can resolve the bacterium and roughly see it's shape (. or - or ~) but not much more. To see it you have to adjust your condenser for maximum resolution - this is close to the top. Do you have an oil immersion objective? To get better contrast it will help to stain bacteria. On a stained slide you can see them with the 40:1 objective as little cloured dots.
Much work with bacteria is done by growing them on agar plated to have more material to observe. The light microscope alone can't tell too much about bacteria. It is the preparation and staining that leads to more information. Bacteria are a better subject for the professional than for the interested hobbyist.

Bob
check your arithmetic, there Bob.

MichaelG.
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Re: Am I doing something wrong?

#9 Post by MichaelG. » Wed Oct 23, 2019 7:30 am

Just a side-note: There is an interesting report in today’s News
https://news.sky.com/story/poor-toilet- ... h-11842110

‘though, of course, the accompanying image of E.coli is not representative of what we can see with the light microscope.

MichaelG.
Too many 'projects'

mnmyco
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Re: Am I doing something wrong?

#10 Post by mnmyco » Thu Oct 24, 2019 8:08 pm

You can read the field guide to bacteria for help on what can be useful when dealing with bacteria. I have a lot of experience in teaching undergraduate microbiology labs. The only thing we use microscopes for is to check microbe shape (which even its good scopes at 100x can be misleading or inconclusive) and results of a stain test.

Mnmyco

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