Chris and I have spent the last several months reading and brainstorming furiously to try and come up with some cool ideas for Cotyledon and to expand our knowledge of Biology (and everything else!). Along the way, we've come across tons of fascinating papers and ideas and we'd like to use these posts as a way to share and discuss them. We'll also use the blog to keep you all informed about our progress with Cotyledon and where we plan on going with it.
This is my first blog-type writing endeavour and it may take me a few weeks to get into the swing of things, so here goes...
I came across a pretty cool fungi-related paper this week (ref below). My first experience with engineering fungi was back in Dr. Nano's lab where I spent a good chunk of time trying to build a DNA construct to be assembled (through homologous recombination) in yeast. The construct was meant to allow us to test a number of different promoters and ribozome binding sites in a cyanobacterium (Synechococcus elongatus). I designed a number of small fragments with overlapping homologous ends, put them into yeast cells where the endogenous recombination system recognized the matching ends on each fragment and ligated them together into one long continous construct. The recombination process itself worked beautifully, it was simple and efficient.
Since then I've poked around into other areas of fungal research and am pretty enamoured at this point... Recycling forest debris (saprotrophs), symbiotically transferring nutrients between plants (mycorrhiza), their psychoactive effects (psilocybes), their commercial cultivation for food... not to mention their potential for biotech applications like bioremediation and biocatalysis... the list goes on.
We've come up with a few cool things to do in some Basidiomycetes and Mycorrhiza (more specifics in a later post!) and I'm thinking something like the oyster mushroom (Pleurotus ostreatus) would be a great organism to test a DIY gene gun apparatus (so much to talk about in later posts...). I picked up a few oyster mushrooms from a local grocer a few months back to start a culture with. I cut a few pieces of tissue out of the inside of the cap (protected from contaminats) and placed it in some sterilized rye grain media. Over the next several weeks, mycelia spread out from the pieces to eventually colonize the entire container. I took the now fully colonized media and placed it into an improvised growth chamber. In the chamber, I burried the culture in some used coffee grounds. The mycelia again spread out to consume the coffee grounds and I'm now patiently awaiting the formation of fruiting bodies. The whole experience has been very interesting, this species is incredibly simple to grow and will colonize cellulosic substrate very quickly.
One of the papers that I came across recently by Arjona et al. (doi:10.1016/j.mycres.2008.12.006 ) demonstrated light controlled induction of fruiting in P. Ostreatus. The mushroom growing industry has known about modulating photoperiod to induce fruiting for some time but these researchers found that stimulation with blue light alone may be sufficient to trigger the developmental process that leads to fruiting morphogenesis. They cautiously suggested that a blue light receptive cryptochrome protein may responsible for this. And this is where things get interesting. That putative cryptochrome may be part of a simple two component sensor and if (potentially a big if) it is sufficient to trigger fruiting, there could be lots of cool things to do with it.
Mushrooms are thought to fruit (form the part that's typically recognized as a mushroom – stem and cap) in reponse to environmental cues including temperature, photoperiod and nutrient availability. Endoegnous factors like circadian cycle and nutrient reserves also likely have roles. If we could pull out a single control mechanism and control it ourselves, for example through transcriptional control of a constitutively activated cryptochrome or a cryptochrome cytosolic signalling domain fused to our own extarcellular signal reception domain, we could connect fruiting body morphogenesis to any input (temperature, chemical, time of day etc.) and potentially port this to other species! Mushrooms on demand anyone?
After about 3 weeks of colonizining the coffee substrate, my P. ostreatus cultures will hopefully be pinning and fruiting soon. In the meantime, I'm going to start looking into a blue light setup, just in case. I'll be posting more pictures over the next few weeks as their development unfolds along with a number of other topics that I've been digging into.
I've started an album for Oyster mushroom pics here: Pleurotus pictures