Checked plates of P. larvae MYPGP agar that were incubated at 37C with 5%CO2 and those incubated at 37C in an anaerobic chamber. These plates have been incubating for seven days.
Unfortunately, it seems that the plates grown in 5%CO2 were contaminated as evident by the pictures below:
Additionally, it appears that P. larvae growth was extremely inhibited in the anaerobic environment. Pictures of the two MYPGP plates containing P. larvae that were grown in the anaerobic chamber for seven days is seen below:
The growth seen from the anaerobic chamber is no where near what is typically observed in 5% CO2. This leads me to the conclusion that the lack of oxygen does not increase spore formation in P. larvae. In the future I will continue to incubate P. larvae on MYPGP agar plates at 37C with 5%CO2 and not in an anaerobic environment.
As for the contamination seen in the top two plates; I believe I know the cause. The cell spreaders used to spread the 100 uL culture were the last two in the bag and I believe that someone else who has been using my spreaders had less than ideal aseptic technique when removing the spreaders. The borrowing of lab supplies despite being labelled continues to be a problem in the lab (pipet tips, spreaders, inoculation needles, etc) and I was hesitant to even use those last two spreaders from the used bag. I do not believe that the culture that these plates were inoculated from was contaminated as they had undergone heat treatment previously to kill off any non-spores present.
Additionally, I was informed that the CO2 incubator had a kink in the CO2 gas hose for an unknown period of time until it was discovered here on the seventh day. This likely means that the concentration of CO2 was not at a constant 5% throughout the time these plates had been incubating.
//EWW
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