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Arthrobacter vanishing plaques
| Link to this post | posted 10 Oct, 2024 14:19 | |
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Hi everyone, We've been working with A. globiformis this semester and have suddenly hit a standstill. For the past two weeks we have been unable to reisolate phage picked from spot plates. Students will plate a dilution series and a beautiful, dense lawn of Arthrobacter shows up, but no plaques. In addition, we have processed 60+ samples in the past few days resulting in zero phage. Any ideas greatly appreciated! |
| Link to this post | posted 10 Oct, 2024 14:32 | |
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Hi Colleen, Does the control phage provide show no plaques also? debbie |
| Link to this post | posted 10 Oct, 2024 15:29 | |
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Completely forgot that I had it! I don't use it past day 1 to avoid students reisolating it. Will let you know tomorrow when the spot plate grows. Thanks, Debbie! Colleen |
| Link to this post | posted 11 Oct, 2024 13:29 | |
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debbie There is no evidence of phage on a plate spotted with Liebe, the positive control. |
| Link to this post | posted 11 Oct, 2024 13:39 | |
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Hi Colleen, The simplest answer is that you are not propagating A. globi any longer. Do you have your original stock material? It is time to revert to that! A good practice is that all cultures be subbed from the parental strain, an F1 or F2 generation is fine, but going beyond that is problematic. Best, debbie |
| Link to this post | posted 11 Oct, 2024 13:40 | |
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Did you change batches of media around the time plating started to fail? In particular, if the Mg/Ca levels are off in the PYCa, that can significantly affect phage sorption & plating efficiency. |
| Link to this post | posted 11 Oct, 2024 13:57 | |
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Thanks, Debbie. I threw out all media and started fresh Monday, still same issue. Started new cultures from stock yesterday, they should be ready for next week's labs. In the meantime, I've started students on Gordonia terrae, which is cooperating. I'll work out the issues with the Arthrobacter and we can go back to it but we are running short on time! Thanks so much for your help! Colleen |
| Link to this post | posted 11 Oct, 2024 14:01 | |
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Terrific! You can do this! debbie |
| Link to this post | posted 16 Oct, 2024 12:59 | |
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And just like that, the phages have popped back up using a subculture from the frozen stock. We are back on track again! Thank you! |
| Link to this post | posted 16 Oct, 2024 13:00 | |
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Excellent! |