Tension extracellular oxygen

While tissue isolation, immortalization, and proliferative status all can severely impact cell culture differentiation, other parameters are also critical such as nutrient concentrations, serum content, hormones, growth factors and cytokines, culture substrata, extracellular matrix components, and oxygen tension. 

Seven of thirty yeast stock cultures, covering nine genera, and thirteen of thirty-nine yeasts isolated from groups gave positive reactions when screened for pectinolytic activity on pectin gel plates. The extracellular pectinolytic activity from Saccharomyces fragilis Y49 was partially constitutive and was repressed by high oxygen tensions. 

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