Hi. There are other suppliers however you'll be looking at an extreme uptick in expense as lab supply websites are quite pricey and shipping is generally not free. If you have a microwave or stove and a scale (I'm assuming a homebrewer would) you can macguyver a recipe together and set your own plates. This is what we do in my lab at least. Food grade agar is plenty good https://www.amazon.com/Agar-Powder-Ounces-Excellent-Strength/dp/B007PJAOG4/ref=sr_1_11?dchild=1&keywords=agar&qid=1585931801&sr=8-11. Petri dishes https://www.amazon.com/Corning-Polystyrene-Petri-Dishes-Lids/dp/B06WP182KT/ref=sr_1_10?dchild=1&keywords=petri+dishes&qid=1585932135&sr=8-10. If you were to go with fisher https://www.fishersci.com/shop/products/bd-difco-dehydrated-culture-media-potato-dextrose-agar-3/p-4901946#?keyword=potato+dextrose+agar its about $74 for just agar without shipping. Grainger is more expensive at $109 but cheaper per gram https://www.grainger.com/product/ACUMEDIA-500g-Potato-Dextrose-Agar-39M260 and also has a late arrival date. Being a lab manager the cost of quick turn around on lab supplies can make your head spin and I would highly recommend amazon just because the price to performance is phenomenal. If you have "fuck you" money to spend on supplies feel free to look at lab supply websites (SigmaAldrich, FisherScientific, VWR) Fisher is usually the cheapest their kind of like the Walmart of the research world. Some smaller companies may be competitive in pricing such as Midwest Scientific, or RPIcorp. No matter how you go about it though shipping costs will be high compared to amazon and many online retailers do not offer free shipping unless you buy hundreds of dollars worth of supplies.
One thing you can do and which shouldn't be very hazardous is use simple agar (basically gelatin), boil it in water, let it rest. Then dilute some liquid yogurt and cover the agar plate with it (just enough to cover the whole agar). Let it sit for 10 minutes then remove most of the liquid. Congratulations, you now have a very rudimentary bacterial lawn (mostly Lactobacillus). If you place a bit of dust (like the one on top of your fridge) or soil in the center of the lawn, cover it and seal it (we use parafilm in the lab but maybe saran wrap will do the trick), after a day or two you will start seeing amoebae leave the dirt and spread across the plate as they eat the bacteria. You probably need an inverted microscope though... Or really thin agar plates that you can still see under a normal microscope.
Edit: Here are some examples (sped up a few times) of some amoebae I isolated a few years ago. That's an E. coli lawn, not yogurt, but the result is almost the same:
http://gifti.me/i/yovesA8dc.gif
The big things that don't move are from a fungus, which shouldn't appear easily on just water (this agar was done with a saline medium that helps isolate amoebae but that is very prone to fungi infection).
Acanthamoeba on agar (still) - notice how there is a front of amoebae moving along a bacterial lawn (upper right, they are clumps of bacteria), leaving almost nothing in their path.
If you have a normal microscope you will probably only be able to use a small objective, 10X or so. Things will seem little. If you do see cells, you might want to go to step 2, which is using an eyedropper and some water (distilled water with a bit of salt would be nice, but tap will probably work for a while) to wash the agar where the amoebae are, then looking at a drop on a microscopy slide, which should allow you to use higher magnifications and see the finer details.
See the morphological difference of the same amoeba in different media? Huge, innit?
Platyamoeba in liquid medium, inverted microscope
If you want to do this and have any questions I can probably come up with a better protocol that is easy to follow.
EDIT 2: Follow up for those interested:
Hey.
For a microscope, I was using some quite expensive ($2000+) research ones, but anything that has a 20X and a 40X objective should work. A binocular microscope (two eyepieces) will be better. I looked around a bit and these are my suggestions:
This one might work but you might want something more powerful
Here are some pipettes just like the ones I was using.
You will want some dishes to pour agar on.
Agar. You'll want to do about 1.5% agar (that's 1.5 grams for each 100ml of water, distilled water is better, tap might workçc) in an Erlenmeyer flask. Microwave and stir (is that the word? I mean move it in circles) until you don't see anything floating (if the agar is decent quality) - Careful! HOT! Use an oven mitt or something similar to hold the flask. Then pour a thin layer (2mm-3mm) on a few of those plates. They can be sealed (parafilm or saran wrap) and refrigerated. You don't want it too thick so that you can slide the plates under the low amplification objectives. If you can't get something to weigh the agar, try something like a dessert spoon (maybe a bit more) and then work from there. Maybe a tea spoon will be good for 50 ml of gel. Let it cool down until solid. Half an hour or an hour should do.
The E. coli is the bacteria I used to feed the amoebae, not the name of that amoeba. You can use diluted yogurt, preferably natural (no sugar added) to minimize growth of other things. A teaspoon per 100 ml or so might be enough. I was doing centrifugation of liquid yogurt but this should work fine.
When you do the yogurt dilution you can take a drop and place it on a slide and see how many dots you see. You don't want it to be just bacteria and you don't want too little. Something like you see here is more than enough. Pour that diluted pure yogurt on the agar plate (thin layer, enough to cover everything when you tilt it back and forth) and let sit for 10 minutes. Then tilt and pipette as much liquid as you can out. It should leave a moist layer of bacteria. Can you see it under the microscope? Does it seem like a good lawn for a hungry amoeba to graze on without having to travel a lot and without being overwhelmed by food? Adjust the yogurt dilution if you need to. You can wait a while for it to dry before you apply the sample. Different amounts of moisture might give you different kinds of protozoans. Lots of moisture will probably give you some ciliates like Paramecium. A drier medium will give you more sturdy amoebae.
Now for the sample. Go outside, grab a piece of dirt the size of your pinky's fingernail and place it on the center of the plate. Simple. Different locations (soil types, root content) and depths will give you different species (although some like Acanthamoeba are quite ubiquitous, even found in salt water). It might take a few days until you start seeing things but sometimes after a single day you will see stuff moving. Remember that these things move slowly, especially on agar, so when you see things that look like cells, stare for a while. When I show people their first amoebae, they rarely see movement at first, only when I tell them to look carefully.
Advanced technique: If you want to see different kinds of amoebae and other microorganisms on the same plate (and also make their advance easier to track), your best bet is to make an X of bacteria instead of filling the whole plate and placing the sample in the middle, like so. You can do the X with a pipette but another way to do it and that reduces the risk of tearing the agar is to place a fat drop on one side, then tilting the plate until the drop reaches the other end. Then do the same for the other line.
If you see amoebae you can pipette a drop or two over the area where you see them and suck it up and down a few times. Maybe using a little strip of parafilm to help release the amoebae from the agar will help (move it over the agar as if you were petting it). Then on a clean dish with wet filter paper (or some other absorbent paper) on the bottom, place a microscopy slide and then place a drop of the amoeba suspension on the slide. Cover the dish (basically making a moist chamber) and let it settle for about 2 hours. Suck the excess water from the slide with a pipette or some absorbent paper (on the edge of the drop), dry the bottom and enjoy.
When you do the observations, play with all the different things that the microscope has. I find the diaphragm very useful to increase contrast.
I found out that you can take decent pictures if you point your cellphone camera at the microscope lens just the right way. It's a good way to record all the diversity.
Do these things on a table or work bench that you can clean properly (75% alcohol will do) before and after. If any of the gunk you try to see gets on the materials you are using (including the microscope objectives), clean that too. I also recommend the use of gloves, for safety and for feeling more like an awesome scientist.
I suggest you do a bit of research before you buy any of these products (although I think you're safe with the pipettes). Read the reviews, compare prices, etc.
Good hunting!
