MacConkey and EMB agar

Next week's lab on Differential and Selective Media calls for MacConkey and EMB agar. I made 800 mL of both this morning.

MacConkey--40 g powder in 800 mL of distilled water

EMB agar--28.8 g powder in 800 mL of distilled water

Both required heating and stirring until dissolved.

I only had 100 g of each of these powders, so if I have two sections of Micro in the fall, I will need to order a bottle of each.

Protozoans Lab a HUGE Hit!

The kids had an absolute blast today looking at all the different types of protozoans, algae, etc. that I ordered in for today's lab. In fact they had so much fun that they want to continue this same lab on Monday. Sure hope the specimens can live until then!

Finding time for transfers

I am trying to find time to make transfers of my original cultures to try to keep viable, pure cultures on hand, but there is just NO time! I did start making them today, but did not get finished before someone grabbed me for yet another something I HAD to do for the Academy. Oh, well, maybe I'll get to finish them tomorrow. These slants are perfect though, so I need to be sure to use that recipe next semester or whenever else I need to make more slants.

Making Nutrient Agar Slants

The nutrient agar slants I made last time didn't set well, so I'm doing it a little differently this morning. Here's the recipe I found:

23 g. nutrient agar per 1000 mL
BOIL and STIR until thoroughly dissolved.
Aliquot 5-7 mL per screw-cap test tube.
Sterilize
Set out to cool on a slant.

Hopefully this will work better.

The first REAL flop in lab!

Nothing, absolutely NOTHING worked today in lab as I had expected! In fact, the only positive I can think of about our results today might be to let the kids see that in a real science lab, where you are doing real research, things OFTEN go WRONG!

To begin, in our antibiotic resistance lab, there were NO zones of inhibition in anyone's plates. I have no idea why that might be. The antibiotics were all new and had been stored in the refrigerator, so should have been very effective. I did ask the students to brainstorm possible things we could try to do differently. They hypothesized that if we had inoculated the plates on the same day that the antibiotics were placed on the plates, that might have made a difference. Someone else said that maybe we should have wet the antibiotic disks, a fact that was supported by several plates which had developed "cracks" in the agar emanating from the antibiotic disk which seemed to suggest that the disks had absorbed the water from the nearby agar. So, I had 20 agar plates left that we could use. Students who wanted to reinoculated those plates and either placed disks on them as before or wet them with some distilled water. I had a few drops of sterile water in the aluminum foil which held the inoculating loops I had sterilized, so one group dipped their disks in the sterile water instead of using distilled water. I guess we will see if any of this changes the outcome of this lab so I'll know how to proceed next year. If nothing changes, I probably will not do this lab next year.

On the switchgrass front, only two or three of the transfers showed any growth today and probably one or two are contaminated. We will continue to watch them for the next little while. So that all students will have a plate of fungus to look at when we study fungi in the next couple weeks, I let them all make transfers out of the fully developed plates I have of two of the fungi I brought with me from UT. I really want them to be able to see the fruiting bodies and make slides of the spores if at all possible. This switchgrass pathogen project may be too ambitious for a large group of high school students, especially without Rifampicin to inhibit bacterial growth.

Switchgrass progress 2

On Thursday, most students were able to find tiny growth to make culture transfers of. There was not a lot of growth in only two days, but there was enough to get them interested. Heather from Junior League was VERY impressed with what she saw and encouraged me to apply for the grant again. I need to make lots more plates of PDA for them to make new transfers to next week. I really need to order the smaller petri dishes for this part since they can only put one transfer into a plate. I'll add that to my wish list for next semester.

Making PDA for switchgrass transferes

I decided to make 1000 mL of Potato Dextrose Agar today instead of 800 mL like I usually make when I make media. That way, there should be plenty of plates available for them to make transfers of any growth that may have come out of their plants since Tuesday. I used 39 g/1000 mL of distilled water to make the PDA.

I also decided to make more water agar and let the students surface sterilize some more plant material so they can each be sure to work with at least a couple different specimens after they are isolated.

Heather from Junior League is coming to visit us today to see what we are doing with the grant money they awarded us in the fall. I wanted her to be able to see several different steps which are involved in the research the kids are undertaking, so she will be able to see them taking cuttings of their live plants, looking for growth out of their samples we did on Tuesday, and hopefully making transfers of fungi growing out of their water agar cultures.

Working with Switchgrass

Finally, yesterday we began the lab work on the switchgrass we've been growing. It was so SLOW getting it started, but today we were ready to begin. Students evaluated their plants for disease and removed some of the diseased tissue (leaves or roots) using scissors they had sterilized in a flame using 70% ethanol. We had a near accident when one student started to go back into the alcohol with the scissors while they were still burning, and I had forgotten to put out glass petri dishes they could use to extinguish such a fire, so I have GOT to remember to put those out any time kids are sterilizing instruments with alcohol and flame.

After making their cuts, students followed the following sterilization protocol:

1. Soak one minute in 95% ethyl alcohol
2. Soak three minutes in 20% clorox
3. Soak one minute in 95% ethyl alcohol
4. Let dry on a piece of paper towel

After their samples dried, they placed the cuttings on water agar, sealed them with parafilm, and placed them in the incubator set at 37 degrees C.

Everything's ALIVE!!!

The switchgrass looks better than it's ever looked! Perhaps I should have been watering them all along from the bottom. My pathogens are doing well, except for two that weren't sealed with parafilm. They are getting a little dry. Guess I'll let the kids make some transfers out of those dishes today. I'm making water agar this morning--going to let the kids surface sterilize the plant material today and put it on plates of water agar. I sure wish I had some Rifampicin to put in with the agar, but I don't. I have autoclaved all the inoculating loops, to help prevent contamination, but I don't know if that will work. Maybe the lactic acid will be here to make PDA plates with when we do the transfers.

Back after Break!

I wonder how many of our switchgrass plants will still be alive tomorrow? I guess we'll see in the morning if you can water for 10 days from the bottom of the pan without drowning them!