Development of a Wine Yeast Strain Capable of Malolactic Fermentation and Reducing the Ethyl Carbamate Content in Wine.

In winemaking, malolactic fermentation (MLF), which converts L-malic acid to L-lactic acid, is often applied after the alcoholic fermentation stage to improve the sensory properties of the wine and its microbiological stability. MLF is usually performed by lactic acid bacteria, which, however, are sensitive to the conditions of alcoholic fermentation. Therefore, the development of wine yeast strains capable of both alcoholic fermentation and MLF is an important task.

Mapping of Prion Structures in the Yeast Rnq1.

The Rnq1 protein is one of the best-studied yeast prions. It has a large potentially prionogenic C-terminal region of about 250 residues. However, a previous study indicated that only 40 C-terminal residues form a prion structure.

CAR1 as a new selective marker for genetic engineering of wine yeasts.

A common problem in engineering industrial yeasts, and wine yeasts in particular, is the lack or scarcity of selective markers for introducing desired genetic changes. Almost all such markers, which are usually auxotrophic mutations, would reduce the growth characteristics of yeast strains. However, a potentially useful marker could be the CAR1 gene encoding arginase, the deletion of which reduces the accumulation of the carcinogen ethyl carbamate in wine, making such a deletion beneficial for wine production and maintainable in wine yeast strains.

Structural Bases of Prion Variation in Yeast.

Amyloids are protein aggregates with a specific filamentous structure that are related to a number of human diseases, and also to some important physiological processes in animals and other kingdoms of life. Amyloids in yeast can stably propagate as heritable units, prions. Yeast prions are of interest both on their own and as a model for amyloids and prions in general.

Amyloid Fragmentation and Disaggregation in Yeast and Animals.

Amyloids are filamentous protein aggregates that are associated with a number of incurable diseases, termed amyloidoses. Amyloids can also manifest as infectious or heritable particles, known as prions. While just one prion is known in humans and animals, more than ten prion amyloids have been discovered in fungi.