Yeast colony characteristics

Colony characteristics —Smooth, cream-colored colonies on YM (yeast malt) agar... 

Cr. laurentii could not be evaluated on the same basis because as a yeast it does not produce hyphae, and only colony development (or the lack thereof) or zone production could be used as criteria. An example of a zone can be seen in Figure 2, presumably caused by the action of an extracellular enzyme on the polymer film which altered the light scattering characteristics. These zones were also detected in areas of high hyphal concentration. 

Figure 3 shows the difference, for example, between a live yeast cell and a dead one. It may turn out that the technique of CSR at a particular low frequency range will be useful as a vital test of cells. Each cell type has its own characteristic spectrum which identifies its state of being, in this case live or dead. Figure 4 illustrates the dependency on colony age. Figures 5-7 show several examples of CSR spectra for different cell lines. 

Cultural characteristics of Pectimtus species have been studied in peptone yeast extract fructose (PYF) medium (http //culturecollection.vtt.fi) and MRS medium. The beer-spoilage species form circular, entire, glistening and opaque colonies on PYF... 

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