About a year ago, we published a paper on electricity-consuming phototrophic microbes in Nature Communications (Guzman et al., 2019 Nature Communications). Here is an "After the Paper" retrospective to the "Behind the Paper" article I wrote about this paper. A lot has happened since then and in the roller coaster year that 2020 has been, we have found more optimism in the microbiology we do on our shocking microbial friends than anything else. Thanks my shocking microbial friends! We owe you one!
First things first, the primary author of this work, who was a graduate student in my lab, successfully defended his thesis work last year in May 2019, shortly after this work was published. He is now a research scientist at Lawrence Livermore National Lab. This work was the pride and joy of his PhD work and rightfully so. Cracking environmental microbes in this way was only possible because of Mike's resilience. Mike developed from a bioinformatician to a microbial physiologist and geneticist, while also learning to be an electrochemist. The things he learned are serving him really well in his new job. So although this paper was just words and figures, to Mike it meant a whole lot more. Congratulations Dr. Guzman!
My lab built on this work also and we have learned that electricity-consuming microbes like our friend, Rhodopseudomonas palustris TIE-1, have many other tricks up their sleeves. For instance, we learned that TIE-1 can use a two-protein outer membrane complex (PioAB) to gobble up electrons from both soluble iron and poised electrodes (Gupta et al., 2020 mBio). Dinesh recently graduated also. So our microbial friends are keeping 2020 much more positive and exciting for us than other world events. Thanks TIE-1 for sharing your secrets with us, and helping us celebrate 2020 a bit! Congratulations Dr. Gupta! Dinesh is heading to UC Berkeley as a post-doctoral fellow.
TIE-1 kept 2020 even more interesting by letting us take many genes away from it only to return them back to it many-fold (Singh et al., 2020 Applied and Environmental Microbiology). Sorry TIE-1, if this wasn't the gift you were hoping for giving the human world two new shiny PhDs! But thanks again for helping us figure out how we can increase intracellular iron and manganese inside microbial cells. I am sure your pathogen friends would be proud of your sacrifice, and maybe share some useful genes with you in the future in the next microbial party.
As a real gift to TIE-1, we wanted to give its house a facelift. Now that we knew that TIE-1 could take electrons from poised electrodes to fix carbon dioxide, we wanted to see if it would like decorated cool electrodes to spruce up its living quarters in 2020 (much like its human friends). We modified electrodes with magnetite nanoparticle anchored graphene, and asked TIE-1 to sit on it (Karthikeyan et al., 2020 Nanotechnology). TIE-1 loved it! But nothing is really free, is it TIE-1? We asked TIE-1 to make a bucket-load of sustainable bioplastic while it was sitting, enjoying the new digs. Thanks again TIE-1! Maybe someday you just sitting around in cool digs will help us pollute planet Earth less with plastic bags and bottles!
So, you can see that TIE-1 has kept 2020 very interesting for us microbe hunters, and helped us rise higher than ever! Thanks TIE-1. We hope you liked our gift. We look forward to an even more exciting and electrifying 2021 with you and your friends!