Model yeast cells

Yeast cells have been used as the model system in these studies.<20,24-291 Typically,... 

Hecht, A., Laroche, T., Strahl-Bosinger, S., Gasser, S.M., and Grunstein, M. (1995) Histone H3 and H4 N-termini interact with the Silent Information Regulators Sir3 and Sir4 a molecular model for the formation of heterochromatin in yeast. Cell 80, 583-592. 

Hemoglobin and heparin present in blood samples are also PCR inhibitors. In one report, these inhibitors were removed from yeast cells (used as the model for blood cells) after DEP cell retention. The yeast cells were retained by DEP, whereas bovine hemoglobin (1 mg/mL) and heparin (13 pg/mL) were washed away [933],... 

Yeast as a source of precursors in the formation of the Acp was then studied in model experiments summarized in Table III. Only low concentrations of the Acp were present (No. 1) in an extract of yeast cells which were ground with silica gel. The amount was slightly enhanced (No. 2) when the yeast/silica gel mixture was boiled for 2 hours. 

Fig. 3.2 Biological abstraction. Yeast cells reflect anaerobic, reductive metabolism (intestine) as well as aerobic, oxidative metabolism (liver), if glycolysis is regarded as the most active pathway. Therefore, the yeast Saccharomyces cerevisiae is a good model organism for studies of xenobiotic metabolism.

An example simulation of this model is illustrated in Figure 3.6, using the parameter values and initial conditions indicated in the legend. Note that the model predicts sustained non-linear oscillations, which have been observed in yeast cells and in extracts from yeast and also mammalian cells [82],... 

Fig. 3A.1 LTSEM images of yeast cells after 24 h of induced autolysis in a model wine system, a Superficial ultrastructure of a yeast cell. b,c Images of fractured empty yeast cells which have lost most of their cytoplasmic content during the autolysis (Maitfnez-Rodrfguez AJ, Polo MC, Carrascosa AV (2001) Int J Food Microbiol 71 45-51. Copyright (2001). Elsevier)...

Martinez-Rodriguez, A.J., Polo, M.C., and Carrascosa, A.V. (2001b). Stractural and ultrastractural changes in yeast cells during autolysis in a model wine system and in sparkling wines. Int. J. Food Microbiol, 71, 45-51. 

Interactions between mannoproteins from yeast cell walls and aroma compounds have been studied by Langourieux and Crouzet (1997). They performed the experiments with crude mannoproteins extracts and observed no effect on the activity coefficient of isoamyl acetate, and a slight decrease on the activity coefficients of ethyl hexanoate and limonene. However, when they purified the mannoproteins or when they used a model glycopeptide, they did not observe any effect on limonene volatility. If the synthetic peptide was heat treated (50 °C), they observed a slight reduction on the activity coefficient of limonene. This was explained by an increase in the hydrophobicity of the glycopeptide after the thermal treatment. 

The main structural constituents of Saccharomyces cerevisiae yeast cell wall are glucans and mannans with a minor proportion of chitin (Walker 1998). Manno-proteins are located in the outer layer of the yeast cell wall and determine most of the surface properties of the wall. Vasserot et al. (1997) studied the capacity of yeast lees to adsorb anthocyanins in an attempt to reduce the detrimental effects of charcoal on the color of red musts and wines. Experiments based on model wine solutions revealed that yeast lees possess a greater affinity for anthocyanins than... 

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