Yeast genetics

Fungi Insect cells Economical, fast, easy, high yield, well characterized genetics (yeast), glycosylation possible, able to secrete correctly folded and processed proteins Glycosylation and other post-translational modifications are often different to mammalian systems... 

Biochemistry resulted from the early elucidation of the pathway of enzymatic conversion of glucose to ethanol by yeasts and its relation to carbohydrate metaboHsm in animals. The word enzyme means "in yeast," and the earfler word ferment has an obvious connection. Partly because of the importance of wine and related products and partly because yeasts are relatively easily studied, yeasts and fermentation were important in early scientific development and stiU figure widely in studies of biochemical mechanisms, genetic control, cell characteristics, etc. Fermentation yeast was the first eukaryote to have its genome elucidated. 

Saccharomyces cerevisiae is well characterized biochemically and genetically and was the organism of choice for most of the eady experiments. However, heterologous expression seems to be better in some of the industrial strains of yeasts such as Pichiapastoris Hansenulapolymorpha Kluyveromyces lactis and Yarrowia lipolytica (25—28). 

E. Sherman and P. Wakem in C. Guthde and G. Pink, eds.. Guide to Yeast Genetics and Molecular Biology, Methods in Engymology, Vol. 194, Academic Press, New York, 1991, p. 38. 

Development of new yeast strains through genetic manipulation techniques has shown some interesting results. Strains with, eg, beta-gluconase activity are produced and have proven satisfactory. 

The fermentation in these big vessels (max 3—5 brews) is normally performed pressureless, but several investigations have been made on fermentation under pressure and using somewhat higher temperatures in order to reduce the time needed still further. Some brewers agree with the statement that no yeast yet known can tolerate this extra stress and at the same time ferment a beet of equivalent excellent quaUty, but new selected yeast strains (genetic engineering) in the future may be better suited to these conditions. 

Genetic manipulation or cloning offers many possibiUties and perhaps there will be yeast strains especially designed for special beers, ie, types, which are usehil because of low diacetyl formation, high—low ester formation, and insensitivity to pressure or high fermentation temperatures or extracellular enzymatic abiUties (P-glucanases). 

OXIDO-REDUCTASES FROM GENETICALLY ENGINEERED YEAST STRAINS AND THEIR BIO ANALYTICAL APPLICATION... 

Peterson, K. R., et al., 1997. Production of transgenic mice widi yeast artificial chromo.somes. Trends in Genetics 13 61-66. 

L Vova TS. 1984. [Study of the mutagenic effect of 5 promising pesticides in mouse bone marrow cultured human peripheral blood lymphocytes, and in the yeast Saccharomyces-cerevisiae.] Tsitol Genet 18 455-457. (Russian)... 

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