Interactions between yeast and bacteria lead to prion induction and stuck fermentations

Really glad we were finally able to get this paper out. Keep any eye out for a follow up paper about the fermentation performance of [GAR+] cells.

Cross-Kingdom Chemical Communication Drives a Heritable, Mutually Beneficial Prion-Based Transformation of Metabolism

Daniel F. Jarosz11, Jessica C.S. Brown1112, Gordon A. Walker, Manoshi S. Datta, W. Lloyd Ung, Alex K. Lancaster, Assaf Rotem, Amelia Chang13, Gregory A. Newby, David A. Weitz, Linda F. Bisson, Susan Lindquist

In experimental science, organisms are usually studied in isolation, but in the wild, they compete and cooperate in complex communities. We report a system for cross-kingdom communication by which bacteria heritably transform yeast metabolism. An ancient biological circuit blocks yeast from using other carbon sources in the presence of glucose. [GAR+], a protein-based epigenetic element, allows yeast to circumvent this “glucose repression” and use multiple carbon sources in the presence of glucose. Some bacteria secrete a chemical factor that induces [GAR+]. [GAR+] is advantageous to bacteria because yeast cells make less ethanol and is advantageous to yeast because their growth and long-term viability is improved in complex carbon sources. This cross-kingdom communication is broadly conserved, providing a compelling argument for its adaptive value. By heritably transforming growth and survival strategies in response to the selective pressures of life in a biological community, [GAR+] presents a unique example of Lamarckian inheritance.

Ever wonder what the difference is between Ale vs. Lager yeast?

Biochemistry, Molecular, Cellular & Developmental Biology

Despite being a yeast researcher, and supposedly having a pretty good handle on yeast genetics, I have always struggled to fully understand what the underlying genetic differences are between ale and lager yeasts. Thanks to a great article by Martha Harbison from Popsci, and research done by Libkind et al, I have finally figured it out!

Generally ales are fermented warmer with”top fermenting” yeast, and produce more fruity esters as a result. Lagers tend to be fermented cooler with “bottom fermenting” yeast, and produce more “reductive” or sulfur characters.

Ale vs. Larger

This description, while great for brewers was always unsatisfactory to me as someone with an interest in genetics and taxonomy. This was further complicated by the interchangeable use of S. calsbergensis and S. pastorianus. Top fermenting yeast are generally just plain old Saccharomyces cerevisiae. Bottom fermenting yeasts are generally more variable and have allotetraploid chromosomes, i.e. 4 chromosomes made up of mixed…

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