Gene Induction in Fungi – Lamarckian?
As some of you may recall I wrote that I was experimenting with laboratory propagation of volvariella volvacea (Chinese Straw Mushrooms). Recently, among several other lines of R&D, I was experimenting with hydrogels as a nutrient media. So far I’ve been using them as an agar replacement with mixed results. I think the mixed results are due to uneven moisture distribution in the fine powder form I was using but that’s neither here nor there. Since the hydrogels can be loaded with nutrients at room temperature (the big advantage over agar) I decided to play around with another sterilant that would decompose at temperatures required to melt agar. I’ve been extremely successful using ampicillin at 1mg/20ml to prevent bacterial contamination in agar cultures – haven’t had a single bacterial infection in hundreds of agar plates. Ampicillin however breaks down quickly at temperatures over 60C so it must be added to agar at a critical stage after it’s cooled down (agar melts at 95C) some but before it solidifies (about 40C). This requires pouring fast and keeping a 60C water bath on the bench. However, ampicillin is so inexpensive it can be considered free of cost compared to wide spectrum antibiotics that survive pasteurization and autoclave temperatures. Once poured, ampicillin plates must be refrigerated until use as ampicillin in solution breaks down quickly at room temperature (a matter of days).