Link to this post | posted 28 Sep, 2022 18:34
cheryl.brown@mnstate.edu	Update: Microbacterium foliorum grows faster and more yellow with soy peptone in the media. No data yet on if that affects susceptibility to phages.

Link to this post | posted 27 Sep, 2021 14:50

cheryl.brown@mnstate.edu

Thank you. As a follow-up, are you aware of anyone else having difficulties with VWR filters recently? We have been using the same filters for 3 years and this fall is the first time we have had the problem. It seems like a QA failure. We ran a test with the current filters and some others on hand, and, using the same force in both, the other filters (also .22 micron syringe filters), only the VWR ones had the contamination problem. I have some .2 micron PES filters on hand. Can those be used in this application? We are also going to tweak the pre-filter/coffee filter step to further decrease particles in samples.

Link to this post | posted 24 Sep, 2021 19:35

cheryl.brown@mnstate.edu

We have been plagued with recurrent contamination problems on plates. One of the confusing factors was the fact that the populations of contaminants was varied. We have widespread, but inconsistent, contamination. I just ran a test yesterday, following the student protocols. I soaked the soil, ran it through a coffee filter, and then through a syringe filter. One sample was more plant material, so the broth needed no force to go through. The other sample was a fine, silty soil, and considerable pressure was needed to get it filtered. There was no obvious break or breach, as the same pressure was needed the entire time. I then plated the filtrate with sterile top agar and no culture. The "forced" plate was covered with bacteria. Is there a change in protocol needed? Additional pre-filtering?

Link to this post | posted 17 Sep, 2021 21:41
cheryl.brown@mnstate.edu	Hello all, Recently we have been having more issues with bubbles in our agar plates. I have extended the "rest" time after adding CaCl2 and dextrose to allow any foam from swirling to dissipate, but still getting bubbles in my plates. Is there an additive that works with PYCa and M. foliorum that is anti-foam or anti-bubble? Do any of you use it or have you?

Link to this post | posted 17 Sep, 2021 21:36
cheryl.brown@mnstate.edu	Hello all, Recently we have been having more issues with bubbles in our agar plates. I have extended the "rest" time after adding CaCl2 and dextrose to allow any foam from swirling to dissipate, but still getting bubbles in my plates. Is there an additive that works with PYCa and M. foliorum that is anti-foam or anti-bubble? Do any of you use it or have you?

Link to this post | posted 05 Feb, 2021 19:38
cheryl.brown@mnstate.edu	Will do. It’s worth a try. I will do side-by-side comparison with the two hosts we use. Edited 05 Feb, 2021 19:38

Link to this post | posted 04 Feb, 2021 15:13
cheryl.brown@mnstate.edu	I have another PYCa media question. Does the type of peptone you get affect the media? We have been using VWR 97064-330, but there is a non-animal, defatted soy peptone (97064-186) for less than half the price. Has anyone used this? Does the source of the proteins matter in this application?

Link to this post | posted 22 Jan, 2021 20:44
cheryl.brown@mnstate.edu	We have had some issues with our PYCa agar getting dark while being held at 45-50 C. I am trying to figure out if it could be one of the ingredients, as we did buy new yeast extract and peptone, or if this is normal and harmless.