Cultures, yeast

National Collection of Yeasts Cultures, maintained of the Brewing Ind. Res. Foundation, Nat-field, Surrey, England... 

Fungicidal activity was determined by the disc method and zones of inhibition were recorded by measuring the diameter (mm) of the inhibition zone. Yeast cultures (S. cerevisiae) showed growth inhibition (clear area surrounding disc) by sediment extracts from all stations when compared to control discs. HPLC analysis of sediment extracts showed more than 20 components in the migration profile of each station. Of these components, a fraction demonstrated to possess cytolytic activity in the crude extract (Ve = 24 ml) was present in all stations when compared to the migration profile of the active fraction (Figure 2). 

The required volume of 50% Ni-silica slurry (7.5 /d/100 ml of starting yeast culture) is equilibrated just before use in buffer BB by two washes each of 500 pi. The resin is collected by centrifugation at 1000 rpm for 2 min in an Eppendorf F 45-24-11 rotor to complete each wash. 

The following protocol is one of the versions of the hot phenol method and it is scaled for 100 to 150 ml of mid-log yeast culture (OD60o- 0.5-0.7). For different cell amounts, simply adjust the solution volumes. 

S.A. Siano and R. Mutharasan, NADH and flavin fluorescence responses of starved yeast cultures to substrate additions, Biotechnol. Bioeng. 34, 660-670 (1989). 

Today, there are a wide variety of laboratory protein expression systems available, ranging from cell-free systems over bacterial and yeast cultures to eukaryotic models including the Xenopus oocytes or insect and mammalian cell cultures, some of which even form polarised epithelial-like cells layers. In Table 24.1, an overview of the most important systems, as well as their particular strength and weaknesses in the expression of transmembrane transport proteins is provided. 

Yeast cultures Similar to bacterial Often misfolding, Like bacteria, functional... 

Sharp, D.G Parry, J.M. (1981a) Induction of mitotic gene conversion by 41 coded compounds using the yeast culture JDl. In de Serres, F.J. Ashby, J., eds, Progress in Mutation Research, Vol., Evaluation of Short-Term Tests for Carcinogens. Report of the International Collaborative Program, Amsterdam, Elsevier/North-Holland, pp. 491-501... 

Such changes in allocation are common in the life of a cell. Louis Pasteur was the first to describe the large (greater than tenfold) increase in glucose consumption by a yeast culture when it was shifted from aerobic to anaerobic conditions. This phenomenon, called the... 

Proper, timely addition of SO 2 Temperature control during fermentation Pure yeast cultures... 

Pure Yeast Culture. Recheck population periodically for purity. If a wild yeast population builds up significantly, discard the culture and begin again from a slant. Some wineries are using mass pitching techniques with dry or frozen yeast very successfully. This eliminates the need for any monitoring of culture population. Wild yeasts often cause unreliable and erratic fermentation rates, and this is often accompanied by off odors and off flavors in the wine. Erratic fermentations also often invite bacterial contamination. 

Storage medium for yeast cultures (MYGP/YM medium)... 

A yeast culture is fermenting glucose to ethanol. To ensure that the C02 released during fermentation is radiolabeled, what carbon(s) of glucose must be labeled with l4C ... 

Inoculate 1 mL yeast culture into the flask containing the sterilized medium. Be careful not to contaminate the pipette, plug, or the flask during the inoculation. To minimize the chance of contamination, flame the plug and the neck of the flask after removing the plug for the inoculation. 

Media and protocols for routine maintenance of E. coli strain FBR5 have been previously described (10). S. cerevisiae (Y-2034 ARS Culture Collection, Peoria, IL) was stored in 50% (v/v) glycerol stocks at -80°C. The yeast culture was routinely maintained on YPD (10 g/L of yeast extract, 20 g/L of peptone, and 20 g/L of dextrose with 20 g/L of Difco agar added for solid medium) and incubated at 32°C. 

It is possible that a toxicity threshold is not achieved at lower severities, reducing the inhibition from these conditions. The corn stover samples were consistently less inhibitory than the aspen wood samples. This is likely owing to the fact that fewer acids are inherent in the corn stover biomass than in the aspen wood biomass. For example, it was found that the pH of the corn stover hydrolysates was higher than the pH of aspen hydrolysates. Further testing is warranted to investigate the difference in the inhibition of the substrates and also to determine whether scatter is to blame for the appearance of a difference between pretreatments with and without carbonic acid when assessing the percent inhibition from Fig. 3. Pretreatment severity showed a marked effect on the degree of inhibition suffered by yeast cultures, but the presence or absence of carbonic acid appears to have had no influence on inhibition. Between the aspen wood and corn stover samples, there appeared to be a difference in inhibition rates. 

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